tag:theconversation.com,2011:/fr/topics/leds-12757/articles
LEDs – The Conversation
2023-12-11T19:02:41Z
tag:theconversation.com,2011:article/218931
2023-12-11T19:02:41Z
2023-12-11T19:02:41Z
8 ways to tone down the Christmas lights to help wildlife – and why we should
<figure><img src="https://images.theconversation.com/files/563148/original/file-20231204-17-esyf9q.jpg?ixlib=rb-1.1.0&rect=32%2C5%2C3551%2C2018&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Christmas_lights_galore.jpg">Agnostic Preachers Kid/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The Australian government has launched a campaign asking people to “<a href="https://www.dcceew.gov.au/campaign/light-pollution">switch off light pollution” to protect wildlife</a>. So, what does the science say? Should we rethink Christmas lights? </p>
<p>In <a href="https://biodiversitycouncil.org.au/media/uploads/2023_12/biodiversity_council_2023_impacts_of_artificial_light_on_wildlife.pdf">our latest report</a>, we reviewed research into the effects of artificial light at night on mammals, frogs, birds and reptiles. We found artificial lights cause problems for a wide range of species, and energy-efficient <a href="https://www.pnas.org/doi/10.1073/pnas.2309539120">LED lights</a> often <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jez.2163">make matters worse</a>. </p>
<p>Most people don’t realise their outdoor lights can harm wildlife. <a href="https://digitalcommons.usu.edu/hwi/vol16/iss1/12/">At Christmas the problem grows</a> because many people put up more decorative lights. </p>
<p>Here we offer eight easy ways to reduce light pollution at Christmas while still showing your festive spirit.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/VAJf3iWqJo0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Bright flashing Christmas lights make our gardens stressful for wildlife (The Biodiversity Council)</span></figcaption>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/getting-smarter-about-city-lights-is-good-for-us-and-nature-too-69556">Getting smarter about city lights is good for us and nature too</a>
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<h2>Easy ways to help</h2>
<p>These eight <a href="https://darksky.org/resources/guides-and-how-tos/lighting-principles/">simple actions</a> will help you support local wildlife while also enjoying festive decorations. Most will save electricity too. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A big red bow on a tree in front of a house" src="https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Daytime decorations are a great way to be festive without contributing to light pollution.</span>
<span class="attribution"><span class="source">Jaana Dielenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<ol>
<li><p>Switch to daytime decorations such as big red bows on trees. Better still, plant a <a href="https://flowerhub.com.au/eduhub/article/7-Native-Australian-Flowers-Associated-with-Christmas">garden with festive colour</a>. Bottlebrush, woolly bush, Christmas bush and Christmas bells are all gorgeous native Australian plants that bloom brightly over Christmas.</p></li>
<li><p>Instead of covering your house and fence, which can also trap animals and block their movement, make your decorative lights window displays. At bedtime, close your curtains so indoor lights cannot disturb either sleeping or active animals outside.</p></li>
<li><p>Don’t leave lights on all night. Pick a short period, and avoid dusk or dawn when animals can be most active. Timers are helpful.</p></li>
<li><p>Instead of bright white or blue lights, use warm colours such as amber or red, as they are less harmful to wildlife. </p></li>
<li><p>Use low-intensity lights – they are supposed to look pretty, not light up a surgery.</p></li>
<li><p>When using spotlights, keep them angled downward and focused on where you need them. Use shields to stop light shining into the sky or nearby vegetation.</p></li>
<li><p>Leave your trees and shrubs as dark refuges for nocturnal wildlife – don’t load them up with lights.</p></li>
<li><p>Camping or travelling? Minimising your light pollution is a great way to help animals in the bush and along the coast. Thousands of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110114">young seabirds</a> and <a href="https://www.dcceew.gov.au/campaign/light-pollution/turtles">baby turtles</a> die on their first trip because artificial lights attract them and cause them to move in the wrong direction. </p></li>
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<a href="https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bright red botttlebrush flowers against a blue sky" src="https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plants like bottlebrushes and Christmas bells can add a festive feel to gardens.</span>
<span class="attribution"><span class="source">Zeynel Cebeci/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bright-city-lights-are-keeping-ocean-predators-awake-and-hungry-68965">Bright city lights are keeping ocean predators awake and hungry</a>
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<h2>Why get involved?</h2>
<p>Research in Australia and overseas has found artificial light at night has a <a href="https://biodiversitycouncil.org.au/media/uploads/2023_12/biodiversity_council_2023_impacts_of_artificial_light_on_wildlife.pdf">wide range of harmful effects</a> on many types of animals, from making them <a href="https://www.sciencedirect.com/science/article/pii/S0269749121003559">stressed</a> and <a href="https://digitalcommons.usu.edu/hwi/vol16/iss1/12/">more vulnerable to predators</a>, to changing their <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0085069">reproduction</a> and making migrating birds more likely to <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2101666118">crash into windows</a>. </p>
<p>It’s such a significant issue for our wildlife that the Australian government launched the “<a href="https://www.dcceew.gov.au/campaign/light-pollution/mammals">Let’s switch off light pollution</a>” campaign in November.</p>
<p>You might not realise how <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/geb.12404">important</a> your garden is to wildlife, because most of our mammals and frogs, and many birds and reptiles, are active at night and are great at hiding as they try to stay out of sight of predators. </p>
<p>Depending on where you live, your yard may be visited at night by <a href="https://www.environment.nsw.gov.au/get-involved/sydney-nature/wildlife/mammals-in-sydney">possums, bats, bettongs</a>, <a href="https://www.australiangeographic.com.au/topics/wildlife/2017/10/the-native-animals-youll-find-in-an-aussie-backyard/">bandicoots</a>, gliders, antechinus, echidnas, koalas, owls, tawny frogmouths, bush stone curlew, frogs, snakes, moths and geckos. </p>
<p>You can help these animals by minimising the amount of <a href="https://www.dcceew.gov.au/sites/default/files/documents/fs-light-pollution-guidelines.pdf">artificial light</a> you shine outdoors. </p>
<p>By stopping lights shining up into the sky or out into the distance, you can also help animals further away. <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1708574114">Migrating birds</a> flying high overhead, <a href="https://www.aims.gov.au/information-centre/news-and-stories/blinded-light-tracking-baby-sea-turtles">baby sea turtles</a> and even <a href="https://www.science.org/content/article/blinding-nemo-artificial-lights-prevent-clownfish-eggs-hatching#:%7E:text=Experiment%20suggests%20light%20pollution%20threatens%20sea%20creatures&text=The%20experiment%20included%2010%20clownfish,them%20hatched%2C%20National%20Geographic%20reports.">fish</a> in the coast can be disturbed by artificial <a href="https://link.springer.com/article/10.1007/s11252-021-01149-9">sky glow</a>, which they <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0017307">see from far away</a>. </p>
<p>Unfortunately, increasingly common energy-efficient <a href="https://www.pnas.org/doi/10.1073/pnas.2309539120">LED lights</a> appear to have <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jez.2163">greater impacts</a> on many animal species <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12758">than other lighting types</a> because they are rich in short-wavelength white and blue light. That means minimising the amount of scattered light has become more important than ever. </p>
<p>Blue light at night is a <a href="https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side">problem for humans too</a> and can make it hard to sleep, which is why many mobile phones have a night-light setting that reduces blue light and makes the phone glow appear orange-tinted. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large tree covered in fairy lights at night" src="https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Trees provide vital habitat for wildlife, but when they are lit like this few animals can use them.</span>
<span class="attribution"><span class="source">Mick Haupt/Unsplash</span></span>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/yes-the-state-of-the-environment-is-grim-but-you-can-make-a-difference-right-in-your-own-neighbourhoood-187259">Yes, the state of the environment is grim, but you can make a difference, right in your own neighbourhoood</a>
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<h2>Your lighting choices make a difference</h2>
<p>At Christmas and year-round, minimising light pollution is a great way to help wildlife. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bandicoots occur in many urban areas around Australia. Artificial lighting disturbs the bandicoot’s vision and makes them more visible to predators.</span>
<span class="attribution"><span class="source">Mark Gillow/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
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<p>Light pollution is not the only problem facing our wildlife, but it can make it much harder for animals to survive other pressures. </p>
<p>For some species, such as <a href="https://www.jstor.org/stable/44973632">seabirds</a>, light pollution is one of the biggest threats to their survival. </p>
<p>Even though urban areas are already <a href="https://www.science.org/doi/full/10.1126/sciadv.1600377">bright at night</a>, your <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2101666118">actions still make a difference</a>. </p>
<p>Like other types of pollution such as carbon emissions, <a href="https://darksky.org/news/light-is-energy-estimating-the-impact-of-light-pollution-on-climate-change/">light pollution adds up</a>. This means every <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110114">light you can turn off</a>, turn down or stop pointing into nature helps. If many people get involved, the difference we can make will be enormous. </p>
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<strong>
Read more:
<a href="https://theconversation.com/artificial-light-at-night-can-change-the-behaviour-of-all-animals-not-just-humans-183028">Artificial light at night can change the behaviour of all animals, not just humans</a>
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<img src="https://counter.theconversation.com/content/218931/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaana Dielenberg works for the Biodiversity Council. The Biodiversity Council was founded by 11 universities and receives support from The Ian Potter Foundation, The Ross Trust, Trawalla Foundation, The Rendere Trust, Isaacson Davis Foundation, Coniston Charitable Trust and Angela Whitbread. Jaana is employed by The University of Melbourne and is a Charles Darwin University Fellow.</span></em></p><p class="fine-print"><em><span>Sarah Bekessy receives funding from the Australian Research Council, the National Health and Medical Research Council, the Ian Potter Foundation and the European Commission. She is a lead councillor of the Biodiversity Council, a board member of Bush Heritage Australia, a member of WWF's Eminent Scientists Group and a member of the Advisory Group for Wood for Good.</span></em></p><p class="fine-print"><em><span>Loren Fardell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
A new report from the Biodiversity Council reveals the disturbing effects of artificial light on
Australia’s nocturnal animals. Here’s how you can help wildlife at Christmas and all year round.
Jaana Dielenberg, University Fellow, Charles Darwin University
Loren Fardell, Research Fellow, The University of Queensland
Sarah Bekessy, Professor in Sustainability and Urban Planning, Leader, Interdisciplinary Conservation Science Research Group (ICON Science), RMIT University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/208859
2023-10-02T19:11:50Z
2023-10-02T19:11:50Z
What has the Nobel Prize in Physics ever done for me?
<figure><img src="https://images.theconversation.com/files/551265/original/file-20230930-15-nkkytb.jpeg?ixlib=rb-1.1.0&rect=53%2C0%2C6000%2C3997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/luminous-white-led-bulb-on-wooden-2096282497">Shutterstock</a></span></figcaption></figure><p>Each October, physics is in the news with the awarding of the Nobel Prize. The work acknowledged through this most prestigious award often seems far removed from our everyday lives, with prizes given for things like “<a href="https://www.nobelprize.org/prizes/physics/1966/">optical methods for studying Hertzian resonances in atoms</a>” and “<a href="https://www.nobelprize.org/prizes/physics/1999/">elucidating the quantum structure of electroweak interactions</a>”.</p>
<p>However, these lauded advances in our basic understanding of the world often have very real, practical consequences for society.</p>
<p>To take just a few examples, Nobel-winning physics has given us portable computers, efficient LED lighting, climate modelling and radiation treatment of cancer. </p>
<h2>Thin magnets and portable computers</h2>
<p>In 2007, the physics Nobel was awarded jointly to Peter Grünberg and Albert Fert for the discovery of “<a href="https://www.nobelprize.org/prizes/physics/2007/press-release/">giant magnetoresistance</a>”. </p>
<p>In the late 1980s, Grünberg and Fert (and their research groups) were independently studying very thin layers of magnets. They both noticed that electricity flowed through the layers differently depending on the direction of the magnetic fields.</p>
<p>These teams were looking to understand fundamental properties of very thin magnets. However, their findings led to something we now take for granted: portable computers. </p>
<figure class="align-center ">
<img alt="A photo of an opened hard drive on a yellow background." src="https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The ‘giant magnetoresistance’ effect won its discoverers the 2007 Nobel Prize in Physics – and made portable hard drives possible.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hard-disk-drive-open-cover-computer-2115380288">Shutterstock</a></span>
</figcaption>
</figure>
<p>At the time, most computers stored information on a hard disk drive made of a magnetic material. To read the information from the drive, a very small and very accurate magnetic field sensor is needed. </p>
<p>The discovery of giant magnetoresistance allowed for the development of far more sensitive sensors, which in turn made hard disk drives and computers smaller. (Today, magnetic hard disk drives are being overtaken by even smaller <a href="https://en.wikipedia.org/wiki/Solid-state_drive">solid state drives</a>.)</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-store-data-on-magnets-the-size-of-a-single-atom-82601">How to store data on magnets the size of a single atom</a>
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</p>
<hr>
<p>In short, we would not have laptops without the discovery that won the 2007 Nobel Prize in Physics. </p>
<p>The effect of this research – like that of so much fundamental research – was completely unanticipated.</p>
<h2>A light bulb moment</h2>
<p>Sometimes, however, physics research does have a practical goal all along. One such example is the quest for energy-efficient lighting.</p>
<p>Old-fashioned incandescent light bulbs are highly inefficient. Because they work by heating a wire until it glows, they waste a lot of energy as heat. In fact, less than 10% of the energy they consume goes to producing light. </p>
<p>In the 1980s, scientists realised light emitting diodes, or LEDs – small electronic components that emit light of a specific colour – would make more efficient light sources. But there was a problem. Although red and green LEDs had been developed in the middle of the twentieth century, nobody knew how to make a blue LED.</p>
<p>LEDs are thin sandwiches of materials that respond to electricity in a very particular way. When an electron moves from one energy level to another inside the material, it emits light of a specific colour. </p>
<p>All three colours of light (red, green and blue) would be needed to produce the kind of white light people want in their homes and workplaces. </p>
<figure class="align-center ">
<img alt="A photo of a strip of blue LED lights against a dark background." src="https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The invention of blue LEDs made it possible to create white light far more efficiently than with incandescent bulbs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vertical-shot-blue-led-tape-glowing-2101501642">Shutterstock</a></span>
</figcaption>
</figure>
<p>In the early 1990s, in the culmination of almost 30 years of work by many groups, the missing blue LEDs were found. In 2014, Isamu Akasaki, Hiroshi Amano and Shuji Nakamura <a href="https://www.nobelprize.org/prizes/physics/2014/press-release/">received the physics Nobel</a> for the discovery. </p>
<p>The layers of material chosen to make up the sandwich, plus the quality of each layer, had to be refined in order to make the first blue LED. Since the initial discovery, materials scientists have continued to improve the design and manufacture to make blue LEDs more efficient.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/your-phone-screen-just-won-the-nobel-prize-in-physics-32456">Your phone screen just won the Nobel Prize in physics</a>
</strong>
</em>
</p>
<hr>
<p>Lighting accounts for up to 20% of total electricity consumption. LEDs use roughly <a href="https://www.sustainability.vic.gov.au/energy-efficiency-and-reducing-emissions/save-energy-in-the-home/lighting/choose-the-right-led-lighting">one sixth as much energy</a> as incandescent light bulbs. They also last much longer, with a lifetime of around 25,000 hours. </p>
<h2>Climate models, radiation and beyond</h2>
<p>Environmental endeavours are probably not what springs to mind when you think of the Nobel Prize in Physics. Yet another example also comes to mind, the study of a chaotic and complex system with great importance to us all: Earth’s climate.</p>
<p>Half of the 2021 Nobel Prize in Physics was given to Syukuro Manabe and Klaus Hasselmann, scientists who developed <a href="https://www.nobelprize.org/prizes/physics/2021/summary/">early models for Earth’s weather and climate</a>. Their work also linked global warming to human activity.</p>
<figure class="align-right ">
<img alt="A black and white photograph portrait of a woman." src="https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=815&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=815&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=815&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1025&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1025&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1025&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Marie Curie was awarded the Nobel Prize in Physics in 1903 for her work on radioactivity.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Marie_Curie#/media/File:Marie_Curie_c._1920s.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Of the 222 people awarded the physics Nobel since 1901, <a href="https://theconversation.com/and-then-there-were-three-finally-another-woman-awarded-a-nobel-prize-in-physics-104323">only three have been women</a>. The most famous of those three is perhaps Marie Curie, who took home one quarter of the prize in 1903. </p>
<p>Curie’s work on understanding how atoms can decay into other kinds of atoms, producing nuclear radiation, profoundly changed life in the twentieth century.</p>
<p>The study of nuclear radiation led to the development of nuclear weapons, but also to radiation treatment for cancer. And further, it has led to carbon dating to determine the age of artefacts, allowing us to better understand <a href="https://www.ansto.gov.au/news/radiocarbon-dating-supports-aboriginal-occupation-of-south-australia-for-29000-years">ancient civilisations</a>. </p>
<p>So when we find out who is awarded the 2023 Nobel Prize in Physics, no matter what it’s for – and prospects include research on quantum computing, “slow light” and “self-assembling matter” – we can be sure of one thing. The awarded research will likely end up affecting our lives in extraordinary ways that may not at first be apparent.</p><img src="https://counter.theconversation.com/content/208859/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Livesey does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
The science that wins the Nobel Prize in Physics each year can be hard to get your head around – but it often has real everyday implications.
Karen Livesey, Senior Lecturer of Physics, University of Newcastle
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/199383
2023-02-23T13:15:36Z
2023-02-23T13:15:36Z
Night skies are getting 9.6% brighter every year as light pollution erases stars for everyone
<figure><img src="https://images.theconversation.com/files/510410/original/file-20230215-24-phgv5z.jpg?ixlib=rb-1.1.0&rect=747%2C249%2C5060%2C1458&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">All human development, from large cities to small towns, shines light into the night sky. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/evobenny/38510489362/">Benny Ang/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>For most of human history, the stars blazed in an otherwise dark night sky. But starting around the Industrial Revolution, as artificial light increasingly lit cities and towns at night, the stars began to disappear.</p>
<p>We are <a href="https://scholar.google.com/citations?user=OrRLRQ4AAAAJ&hl=en&oi=ao">two</a> <a href="https://noirlab.edu/science/about/scientists-at-noirlab">astronomers</a> who depend on dark night skies to do our research. For decades, astronomers have been <a href="https://about.ifa.hawaii.edu/facility/mauna-kea-observatories/">building telescopes</a> in the <a href="https://www.smithsonianmag.com/travel/star-trekking-chile-astronomy-180955798/">darkest places</a> on Earth to <a href="https://doi.org/10.1007/s00159-010-0032-2">avoid light pollution</a>. </p>
<p>Today, most people live in cities or suburbs that <a href="https://doi.org/10.1038/457027a">needlessly shine light into the sky at night</a>, dramatically reducing the <a href="https://doi.org/10.1126/sciadv.1600377#body-ref-R3">visibility of stars</a>. Satellite data suggests that light pollution over North America and Europe has remained <a href="https://www.science.org/doi/10.1126/sciadv.1701528">constant or has slightly decreased</a> over the last decade, while <a href="https://www.mdpi.com/2072-4292/9/8/798">increasing in other parts of the world</a>, such as Africa, Asia and South America. However, satellites miss the blue light of LEDs, which are <a href="http://dx.doi.org/10.2760/759859">commonly used for outdoor lighting</a> – resulting in an underestimate of light pollution.</p>
<p>An international citizen science project called <a href="https://globeatnight.org">Globe at Night</a> aims to measure how everyday people’s view of the sky is changing.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A number of panels showing different numbers of stars." src="https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Globe at Night survey asks users to select which panel – each representing different levels of light pollution – best matches the sky above them.</span>
<span class="attribution"><a class="source" href="https://globeatnight.org/webapp/">The Globe at Night</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Measuring light pollution over time</h2>
<p>Relying on citizen scientists makes it much easier to take multiple measurements of the night sky over time from many different places. </p>
<p>To provide data to the project, volunteers enter the date and time, their location and local weather conditions into an <a href="https://globeatnight.org/webapp/">online reporting page</a> anytime an hour or more after sunset on certain nights each month. The page then shows eight panels, each displaying a constellation visible at that time of year – like Orion in January and February, for example. The first panel, representing a light-polluted night sky, only shows the few brightest stars. Each panel shows progressively more and fainter stars, representing darker and darker skies. The participant then matches what they see in the sky with one of the panels. </p>
<p>The Globe at Night team launched the report page as an online app in 2011, just at the beginning of widespread adoption of LEDs. In <a href="https://doi.org/10.1126/science.abq7781">the recent paper</a>, the team filtered out data points taken during twilight, when the Moon was out, when it was cloudy or when the data was unreliable for any other reason. This left around 51,000 data points, mostly taken in North America and Europe. </p>
<p>The data shows that the night sky got, on average, <a href="https://doi.org/10.1126/science.abq7781">9.6% brighter every year</a>. For many people, the night sky today is twice as bright as it was eight years ago. The brighter the sky, the fewer stars you can see.</p>
<p>If this trend continues, a <a href="https://eos.org/articles/starry-nights-are-disappearing">child born today</a> in a place where 250 stars are visible now would only be able to see 100 stars on their 18th birthday. </p>
<h2>Causes, impacts and solutions</h2>
<p>The main culprits driving increasing brightness of the night sky are urbanization and the growing use of <a href="http://dx.doi.org/10.2760/759859">LEDs for outdoor lighting</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two pictures of the constellation Orion with one showing many times more stars." src="https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The more light pollution there is, the fewer stars a person can see when looking at the same part of the night sky. The image on the left depicts the constellation Orion in a dark sky, while the image on the right is taken near the city of Orem, Utah, a city of about 100,000 people.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/79297308@N00/3180280752">jpstanley/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The loss of dark skies, both from light pollution and also from <a href="https://doi.org/10.1093/mnrasl/slab030">increasing numbers of satellites orbiting Earth</a>, threatens our ability as astronomers to do <a href="https://doi.org/10.1007/s00159-021-00138-3">good science</a>. But everyday people feel this loss too, as the degradation of dark skies is also a loss of human <a href="https://www.darksky.org/light-pollution/night-sky-heritage/">cultural heritage</a>. Starry night skies have inspired artists, writers, musicians and philosophers for thousands of years. For many, a star-filled sky provides an irreplaceable sense of awe.</p>
<p>Light pollution also interferes with the daily cycle of light and dark that <a href="https://ec.europa.eu/research-and-innovation/en/horizon-magazine/light-pollution-altering-plant-and-animal-behaviour">plants and animals</a> use to regulate sleep, nourishment and reproduction. Two-thirds of the world’s key biodiversity areas are <a href="https://www.upi.com/Science_News/2019/02/11/Light-pollution-affects-most-of-the-planets-key-wildlife-areas/1451549899187">affected by light pollution</a>.</p>
<p>Individuals and their communities can make simple changes to <a href="https://www.darksky.org/light-pollution/light-pollution-solutions/">reduce light pollution</a>. The secret is using the right amount of light, in the right place and at the right time. Shielding outdoor light fixtures so they shine downward, using bulbs that emit more yellow-colored light instead of white light and putting lights on timers or motion sensors can all help reduce light pollution.</p>
<p>The next time you are far away from a major city or another source of light pollution, look up at the night sky. A view of the roughly <a href="https://www.theatlantic.com/technology/archive/2013/11/how-many-stars-are-there-in-the-sky/281641/">2,500 stars you can see with the naked eye</a> in a truly dark sky might convince you that dark skies are a resource worth saving.</p><img src="https://counter.theconversation.com/content/199383/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Impey receives funding from the National Science Foundation and Epic Games.</span></em></p><p class="fine-print"><em><span>Connie Walker works for NSF's NOIRLab and the International Astronomical Union. She is a member of the American Astronomical Society's COMPASSE and on the Board of Directors for the International Dark-Sky Association.</span></em></p>
With the help of thousands of citizen scientists, a new study measured exactly how much brighter night skies are getting every year.
Chris Impey, University Distinguished Professor of Astronomy, University of Arizona
Connie Walker, Scientist, National Optical-Infrared Astronomy Research Laboratory
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/154028
2021-06-24T13:16:19Z
2021-06-24T13:16:19Z
Europe is running out of semiconductors – here’s what it can learn from tech survivor Osram
<figure><img src="https://images.theconversation.com/files/408142/original/file-20210624-23-1ixxvwh.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Germany's Osram dominates the market in automotive LEDs.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-detail-on-one-led-headlights-1283222458">i viewfinder</a></span></figcaption></figure><p>The <a href="https://theconversation.com/how-the-world-ran-out-of-semiconductors-156532">shortage of semiconductor chips</a> has exposed the vulnerability of European high-tech manufacturers that rely heavily on chip imports from Asia. The automotive sector alone, traditionally a European high-tech stronghold, is <a href="https://finance.yahoo.com/news/automotive-chip-shortage-cost-estimate-040100144.html">expected to</a> take a US$110 billion (£79 billion) hit over the coming years as a result.</p>
<p>In 2020, high-tech products <a href="https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Production_and_international_trade_in_high-tech_products#Manufacturing_of_high-tech_products">represented approximately 20%</a> of total exports from the European Union by value, with other major sectors including pharmaceuticals, telecoms, aerospace and armaments. Enjoying annual growth rates upward of 10% before the semiconductor shortage and employing more than 3.5 million workers, high-tech is the fastest growing European industry by far. </p>
<p>Considering the importance and apparent vulnerability of the sector, the EU is scrambling to implement initiatives to encourage domestic chip manufacturing and reboot innovation at home. After all, Europe accounted for about 44% of global semiconductor manufacturing in 1990, compared to <a href="https://www.bloomberg.com/news/newsletters/2021-04-27/europe-is-trying-to-reclaim-its-lost-chipmaking-glory">only around 10% today</a>. This slow decline was the result of manufacturers failing to adapt after domestic first-generation cellphone makers Nokia, Ericsson and Siemens <a href="https://knowledge.insead.edu/strategy/the-strategic-decisions-that-caused-nokias-failure-7766">were usurped</a> by American and Asian competition. </p>
<p>Yet in the midst of this struggle for technological self-sufficiency, a European powerhouse in high-tech manufacturing was created by the <a href="https://uk.finance.yahoo.com/news/ams-ag-ams-announces-start-064017790.html">acquitision of</a> German LED (light-emitting diode) manufacturer Osram by Austrian sensor specialist AMS. The combined company is among Europe’s largest semiconductor firms and holds the <a href="https://seekingalpha.com/article/4415523-top-semiconductor-stocks-in-europe">largest market share</a> in chips supplied to the automotive sector. </p>
<p>It is the latest in a series of mergers and takeovers in semiconductors that are representative of what has been happening in high-tech industries as a whole. Products which were once the exclusive domain of western manufacturers have become increasingly commodified as Asian manufacturers catch up, boosted by government subsidies that have left established companies struggling to compete. Yet at the same time, highly profitable and strategically important niche applications are emerging, which point to opportunities. </p>
<p>To understand why some companies have failed to adapt to a rapidly changing business environment, while others are driving innovation, it’s worth looking at the history of Osram in more detail.</p>
<h2>Spotlight on Osram</h2>
<p>Osram traces its roots back some 115 years to Austrian chemist <a href="https://www.britannica.com/biography/Carl-Auer-Freiherr-von-Welsbach">Carl Auer von Welsbach</a>, who greatly improved on Thomas Edison’s light-bulb designs with the use of a metal filament in 1906. Osram-branded bulbs started manufacturing the same year and went on to become the flagship product for one of the <a href="https://new.siemens.com/global/en/company/about/history/stories/siemens-and-osram.html">biggest lighting companies</a> in the world. Osram later played a key role in the development other lighting technologies, including compact fluorescent light bulbs.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=211&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=211&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=211&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=265&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=265&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406009/original/file-20210613-72921-ucpvll.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=265&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some of Osram’s greatest hits in lighting, L to R: Von Welsbach’s gas mantle and early incandescent light bulb with an osmium filament; first high-frequency electrical ballast for compact fluorescent lamps; high-efficient blue LED with yellow phosphor for white-light generation; heart rate detection using efficient green LEDs in smart watches; quantum dots in LEDs.</span>
<span class="attribution"><span class="source">Wikimedia Commons, Michael Weinold. Adapted from patents: US409530A, US976528A, US4415839A, EP0118100A1, US7078732B1, US20200046275A1 and US10763400B2</span></span>
</figcaption>
</figure>
<p>Key to Osram’s survival over the years has been its ability to adapt by proactively seeking out new markets. Following <a href="https://www.theguardian.com/environment/2012/aug/31/lightbulbs-incandescent-europe">the global effort</a> to phase out incandescent lamps in the 2000s, Osram was well placed to capitalise. Scientists at Osram and the German Fraunhofer Institute <a href="https://patents.google.com/patent/US7078732B1/en">had patented</a> a white LED as early as 1996. This was only weeks after the Japanese researchers that would go on to win the <a href="https://www.nobelprize.org/prizes/physics/2014/summary/">2014 Nobel Prize in physics</a> for their ground-breaking invention, and Osram’s early start in LED research established its IP portfolio.</p>
<p>But when highly subsidised <a href="https://www.nytimes.com/2014/06/18/business/as-led-industry-evolves-china-elbows-its-way-to-the-fore.html">Chinese companies</a> entered the market after 2010, LEDs for general illumination became increasingly ubiquitous and less profitable. Osram instead focused on developing market segments that demanded high-performance LEDs. </p>
<p>Backed by its in-house strength in research and development, fruitful university collaborations, and production capacity in the EU, Osram secured market leadership positions in niche applications like <a href="https://finance.yahoo.com/news/grow-lights-market-worth-4-133000928.html">horticultural lighting</a> for high-yield agriculture, infrared sensors for <a href="https://finance.yahoo.com/news/the-heart-rate-monitor-on-the-apple-watch-is-crazy-118446671314.html?soc_src=unv-sh&soc_trk=pi">heart rate monitoring</a> and lights and sensors for the <a href="https://finance.yahoo.com/news/drowsiness-fatigue-related-road-accidents-150000674.html">automotive industry</a>. </p>
<p><strong>High-performance LED development</strong></p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=357&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=357&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=357&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=449&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=449&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406010/original/file-20210613-73791-wdfwmo.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=449&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Historical development of specialised applications of light-emitting diodes.</span>
<span class="attribution"><span class="source">Wikimedia Commons, Michael Weinold</span></span>
</figcaption>
</figure>
<p>Osram stayed ahead of the competition by moving to niches where higher device performance and electrical efficiency were of paramount importance, rather than low manufacturing cost. The company’s product and IP portfolio today <a href="https://doi.org/10.1016/j.techfore.2010.06.017">remains among</a> the industry’s largest in <a href="https://www.lens.org/">key patent classes</a>. And the takeover by AMS shouldn’t be seen as a sign of failure. It creates a global leader in high-tech optical solutions that has a much better chance of staying ahead of emerging Asian competition in these niche sectors.</p>
<p>Other western companies have not navigated the lighting sector as successfully. General Electric, a long-time competitor, had opted against developing its own LED research department, instead procuring chips from overseas manufacturers to include in its lamps. Faced with increasing economic pressure, and unable to fall back on more specialised products, the company that traces its roots back to Edison had little choice but to <a href="https://theconversation.com/general-electrics-exit-from-lighting-business-is-a-warning-to-other-players-in-the-sector-140181">sell its lighting unit</a> in 2020.</p>
<h2>Lessons to learn</h2>
<p><a href="https://www.ceenrg.landecon.cam.ac.uk/research/climate-change-and-energy-policy/what-factors-drive-innovation-in-energy-technologies-the-role-of-technology-spillovers-and-government-investment">My department’s research</a> has shown that maintaining in-house research capabilities and academic collaborations will be key to the survival of European high-tech companies in the near future. Governments can support these efforts of private industry by strengthening the academic landscape in Europe. This can be achieved through projects like the <a href="https://ec.europa.eu/info/research-and-innovation/funding/funding-opportunities/funding-programmes-and-open-calls/horizon-europe_en">Horizon Europe Programme</a>, which funds both basic university research and collaborative efforts with industry.</p>
<p>In the long run, the best way to ensure the resilience of Europe’s high-tech industries is to “backshore” manufacturing of these products to Europe. With Sino-US tensions only expected to mount in the coming years, this would largely decouple strategic industry sectors from economic sanctions and mitigate geopolitical risks. It would also reduce the risk of the <a href="https://link.springer.com/article/10.1057%2Fs41267-017-0087-7">IP theft</a> in overseas manufacturing.</p>
<p>Two of Europe’s largest suppliers of semiconductor components have already moved a significant part of their production back to Europe: <a href="https://finance.yahoo.com/news/1-infineon-says-meet-chip-102249642.html">Infineon Technologies</a> in Austria and <a href="https://finance.yahoo.com/news/bosch-opens-german-chip-plant-120412027.html">Bosch</a> in Germany. This was enabled by unprecedented levels of factory automation and advanced robotics that is known as the <a href="https://www.forbes.com/sites/bernardmarr/2018/09/02/what-is-industry-4-0-heres-a-super-easy-explanation-for-anyone/?sh=7f79bfc29788">fourth industrial revolution</a>. As the Osram experience shows, controlling the most important parts of your technology is often the secret to long-term survival.</p><img src="https://counter.theconversation.com/content/154028/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Weinold receives funding from the Swiss Study Foundation. The research project of which he is a part receives funding from the Alfred P Sloan Foundation.</span></em></p>
The global semiconductor shortage is causing problems for Europe because it has mostly abandoned manufacturing them.
Michael Weinold, Researcher, Cambridge Centre for Environment, Energy and Natural Resource Governance, University of Cambridge
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/146773
2020-10-02T16:40:43Z
2020-10-02T16:40:43Z
What the world can learn from clean energy transitions in India, China and Brazil
<figure><img src="https://images.theconversation.com/files/359915/original/file-20200924-14-1okfu13.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4493%2C2081&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Jenson / shutterstock</span></span></figcaption></figure><p>If the world is to transition to a climate-compatible future, much will turn on new innovations in clean energy and whether they can be deployed at a large scale. This is especially critical for emerging economies, which are developing their infrastructure and undergoing economic growth and urbanisation at an <a href="http://www.nature.com/articles/d41586-018-02409-z">unprecedented scale</a> and pace, yet still often lack the support for technological innovation found in wealthier countries.</p>
<p>Six of these emerging economies – Brazil, China, India, Indonesia, Mexico and South Africa – contributed <a href="https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-stats-review-2020-full-report.pdf">more than 40%</a> of the global CO₂ emissions in 2019. That’s 1.5 times the combined emissions from the US and Europe. Yet at the same time China, India, and Brazil were the first, fourth and sixth <a href="https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-stats-review-2020-full-report.pdf">largest producers of renewable electricity</a>. These three countries – the largest emerging economies – are now at a crucial juncture, faced with immense potential to become major innovators in the development of clean energy technology. </p>
<p>In a <a href="https://iopscience.iop.org/article/10.1088/2516-1083/abb52b">new paper</a> we explored how fast-growing countries can not only develop their own sustainable systems but provide a source of learning and knowledge to influence global trends. We did this by investigating specific clean energy success stories in the three countries.</p>
<h2>India’s remarkable transition to LEDs</h2>
<p>First is India’s 130-fold expansion of its market for light emitting diode (LED) bulbs in just five years. LED bulbs are more energy efficient and last much longer than incandescent bulbs, tube lights, and compact fluorescent bulbs. In India they are primarily being used for residential lighting and street lamps.</p>
<p>India’s LED transition is estimated to save more than <a href="http://www.ujala.gov.in/">40 terawatt hours (TWh)</a> of electricity each year – roughly enough to power <a href="https://cprindia.org/news/6519">37 million average Indian households</a> or the whole of Denmark for one year. In three years, the country grew from a negligible share of the global LED market to <a href="https://www.sciencedirect.com/science/article/abs/pii/S2214629620300657">about 10%</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph showing big growth in LED light in India." src="https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359892/original/file-20200924-22-qmfej.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lamp sales for different lighting technologies in India. The LED lighting market grew from annual sales of 5 million bulbs to 669 million.</span>
<span class="attribution"><span class="source">Khosla et al (Data: ELCOMA)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Solar energy soars in China</h2>
<p>An equally remarkable transition occurred in China, which has become the top manufacturer and largest market of solar photovoltaic (PV) cells and modules, accounting for 69% of global production. In the past 40 years, solar panel costs have <a href="https://www.sciencedirect.com/science/article/pii/S0301421518305196#f0005">declined by more than 99%</a>, driven recently by low-cost manufacturing in China.</p>
<p>Between 2014 and 2018, <a href="https://iea-pvps.org/wp-content/uploads/2020/02/5319-iea-pvps-report-2019-08-lr.pdf">China added about 158 gigawatts</a> of solar PV – about the same as the <a href="https://www.eia.gov/outlooks/aeo/data/browser/#/?id=19-IEO2019&region=0-0&cases=Reference&start=2010&end=2018&f=A&linechart=Reference-d080819.2-19-IEO2019&sid=Reference-d080819.6-19-IEO2019&sourcekey=0">total power generation capacity of Brazil</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph of solar pv cell production in selected countries." src="https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359894/original/file-20200924-16-1x8r43s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">China’s manufacturing capacity increased more than 25 times during 2008-2017.</span>
<span class="attribution"><span class="source">Khosla et al (Data: IEA-PVPS annual Trends Reports and National Survey Reports for China, Japan, Malaysia, South Korea and the US)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Biofuels in Brazil</h2>
<p>A third success story is that of Brazil’s long-term growth to become the largest producer, exporter and market for ethanol biofuel made from sugarcane.</p>
<p>Ethanol-run vehicles increased their share of Brazil’s new car sales from <a href="http://www.virapagina.com.br/anfavea2019/">30% in 1980 to 90% in 1985</a>. After ethanol stagnated in the 1990s, biofuels were revived by the introduction of flex-fuel vehicles which use any mix of gasoline and ethanol. Their share increased from negligible in 2003 to <a href="http://www.virapagina.com.br/anfavea2019/">85% of new cars sold</a> just five years later – and has remained constant since.</p>
<p>There are some environmental and socioeconomic impacts. These include deforestation for sugarcane plantations, soil erosion, air and water pollution, and the <a href="https://www.tni.org/files/download/ethanol_monopoly_brazil.pdf">consolidation of land ownership</a> among large ethanol producers. But when you look at the <a href="https://irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-P10-Production_of_Liquid-Biofuels.pdf">full lifecycle of sugarcane ethanol fuel</a>, from crop to car, its greenhouse gas emissions are lower than those from gasoline or corn ethanol. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph of ethanol production in Brazil, China and the rest of the world" src="https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359896/original/file-20200924-17-htzetf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ethanol production by country between 2000-2018. Note that US ethanol is almost entirely from corn, whereas Brazil’s is from sugarcane which has lower life-cycle carbon emissions.</span>
<span class="attribution"><span class="source">Khosla et al (Data: OECD)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Three lessons for the rest of the world</h2>
<p>Based on these unexpected clean-energy transitions, we have identified three insights relevant across emerging economies.</p>
<p><strong>1. Public sector enterprises are crucial</strong></p>
<p>In all three cases businesses with significant equity owned by governments played a crucial role. In India, a <a href="https://www.theclimategroup.org/news/indian-government-slashing-costs-led-lights-households">joint venture of four public-sector utilities</a> called EESL bought energy-efficient LED bulbs in bulk, reduced prices using competitive bidding, ran national marketing campaigns, and sold the bulbs to customers through new distribution channels.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"640110425627996160"}"></div></p>
<p>In China, public sector enterprises provided venture capital investments and loans that enabled rapid expansion of private sector solar startups. In Brazil, the leading public oil company bridged the gap between ethanol production and consumer point-of-purchase by buying ethanol from mills, providing storage and transport, and distributing fuel through the country’s largest network of fuel pumps.</p>
<p><strong>2. Domestic choices in a global economy</strong></p>
<p>Second is the need to reinforce complementary links between the global economy and domestic technology choices. For example, India was able to accelerate its LED market because its bulk procurement and bulb distribution policies complemented access to China’s large scale low-cost LED manufacturing. Equally, China’s early domestic support for export-oriented hi-tech manufacturing complemented the growing demand for solar cells in Germany.</p>
<p><strong>3. R&D that unites academia and industry</strong></p>
<p>Finally, engagement between industry and universities and public sector research institutions is essential. For example, Brazil could develop the technology to make ethanol compete on cost with gasoline only because of strong links between public sector research institutes and industry, including the government-funded “<a href="https://revistapesquisa.fapesp.br/wp-content/uploads/2013/07/054-057_genomacana_esp50.pdf">Sugarcane Genome Project</a>”.</p>
<p>Our analysis shows that it is possible for emerging economies to begin from a technologically and economically disadvantaged position and yet successfully accelerate the transition to clean energy technologies. These lessons provide good news, since success or failure in this endeavour will have long-term energy and climate consequences for all.</p><img src="https://counter.theconversation.com/content/146773/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ajinkya Shrish Kamat has not received any funding for the paper discussed in this article. Funding he has received at MIT is independent of this work and is related to other research topics.</span></em></p><p class="fine-print"><em><span>Venkatesh Narayanamurti currently receive funding from the Sloan Foundation on the role of spillovers in clean energy technologies. The work on the perspective was independent of that funding and it is related to other problems.</span></em></p><p class="fine-print"><em><span>Radhika Khosla does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Our research identified three key lessons.
Radhika Khosla, Senior Researcher at the Smith School of Enterprise and the Environment, University of Oxford, University of Oxford
Ajinkya Shrish Kamat, Postdoctoral Associate, Institute for Data, Systems, and Society, Massachusetts Institute of Technology (MIT)
Venkatesh Narayanamurti, Benjamin Peirce Professor of Technology and Public Policy, Harvard University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/133658
2020-09-01T10:57:17Z
2020-09-01T10:57:17Z
How a new solar and lighting technology could propel a renewable energy transformation
<p>The demand for cheaper, greener electricity means that the energy landscape is changing faster than at any other point in history. This is particularly true of <a href="https://www.greentechmedia.com/articles/read/solar-pv-has-become-cheaper-and-better-in-the-2010s-now-what">solar-powered electricity</a> and <a href="https://www.cnbc.com/2019/12/30/battery-developments-in-the-last-decade-created-a-seismic-shift-that-will-play-out-in-the-next-10-years.html">battery storage</a>. The cost of both has dropped at unprecedented rates over the past decade and energy efficient technologies such as <a href="https://www.mordorintelligence.com/industry-reports/led-lighting-market">LED lighting</a> have also expanded.</p>
<p>Access to cheap and ubiquitous solar power and storage will transform the way we produce and use power, allowing electrification of the transport sector. There is potential for new chemical-based economies in which we <a href="https://link.springer.com/article/10.1007%2Fs40243-017-0088-2">store renewable energy as fuels</a>, and support new devices making up an “<a href="https://www.forbes.com/sites/jacobmorgan/2014/05/13/simple-explanation-internet-things-that-anyone-can-understand/#5070dd621d09">internet of things</a>”.</p>
<p>But our current energy technologies won’t lead us to this future: we will soon hit efficiency and cost limits. The <a href="https://iopscience.iop.org/book/978-0-7503-2152-5">potential for future reductions</a> in the cost of electricity from silicon solar, for example, is limited. The manufacture of each panel demands a fair amount of energy and factories are <a href="https://pubs.rsc.org/en/content/articlelanding/2015/ee/c5ee01509j#!divAbstract">expensive to build</a>. And although the cost of production can be squeezed a little further, the costs of a solar installation are now <a href="http://energy.mit.edu/research/future-solar-energy/">dominated by the extras</a> – installation, wiring, the electronics and so on. </p>
<figure class="align-center ">
<img alt="Two workers with white gloves work on a solar panel." src="https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/355805/original/file-20200901-16-tiw12a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Workers in a factory of a Chinese solar panel maker in Hangzhou, China.</span>
<span class="attribution"><span class="source">EPA/STR</span></span>
</figcaption>
</figure>
<p>This means that current solar power systems are unlikely to meet the required fraction of our 30 TeraWatt (TW) global power requirements (they produce less than 1 TW today) <a href="https://pubs.rsc.org/en/content/articlehtml/2016/ee/c6ee00484a">fast enough</a> to address issues such as climate change.</p>
<p>Likewise, our current LED lighting and display technologies are too expensive and not of good enough colour quality to realistically replace traditional lighting in a short enough time frame. This is a problem, as lighting currently accounts for <a href="https://www.theguardian.com/environment/2015/dec/07/plan-for-10-billion-ultra-efficient-leds-lights-up-paris-climate-summit">5%</a> of the world’s carbon emissions. New technologies are needed to fill this gap, and quickly.</p>
<h2>Halide perovskites</h2>
<p><a href="http://www.strankslab.com/">Our lab in Cambridge</a>, England, is working with a promising new family of materials known as <a href="https://www.scientificamerican.com/article/perovskite-solar-cells-could-beat-the-efficiency-of-silicon/">halide perovskites</a>. They are semiconductors, conducting charges when stimulated with light. Perovskite inks are deposited onto glass or plastic to make extremely thin films – around one hundredth of the width of a human hair – made up of metal, halide and organic ions. When sandwiched between electrode contacts, these films make <a href="https://www.nature.com/articles/nnano.2015.90">solar cell or LED devices</a>. </p>
<p>Amazingly, the colour of light they absorb or emit can be changed simply by tweaking their chemical structure. By changing the way we grow them, we can tailor them to be more suitable for absorbing light (for a solar panel) or emitting light (for an LED). This allows us to make different colour solar cells and LEDs emitting light from the ultra-violet, right through to the visible and near-infrared. </p>
<p>Despite their cheap and versatile processing, these materials have been shown to be remarkably efficient as both solar cells and light emitters. Perovskite solar cells hit <a href="https://www.nrel.gov/pv/cell-efficiency.html">25.2% efficiency in 2019</a>, hot on the heels of crystalline silicon cells at 26.7%, and perovskite LEDs are already <a href="https://www.nature.com/articles/s41586-018-0575-3">approaching</a> off-the-shelf organic light-emitting diode (OLED) performances.</p>
<p>These technologies are <a href="https://www.bbc.co.uk/news/business-51799503">rapidly being commercialised</a>, particularly on the solar cell front. UK-based Oxford Photovoltaics has <a href="https://www.oxfordpv.com/news/oxford-pv-places-first-equipment-order-meyer-burger">built a production line</a> and is filling its first purchase orders <a href="https://www.theguardian.com/business/2020/aug/15/uk-firms-solar-power-breakthrough-could-make-worlds-most-efficient-panels-by-2021">in early 2021</a>. Polish company Saule Technologies released prototype products at the end of 2018, including a <a href="https://sauletech.com/saule-technologies-and-skanska-change-construction-industry/">perovskite solar façade pilot</a>. Chinese manufacturer Microquanta Semiconductor expects to produce more than <a href="http://www.xinhuanet.com/english/2020-08/05/c_139267152.htm">200,000 square meters</a> of panels in its production line before year-end. The US-based Swift Solar (a company I co-founded) is pioneering <a href="https://www.swiftsolar.com/">high-performance</a> cells with lightweight, flexible properties. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&rect=144%2C46%2C1646%2C1083&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=352&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=352&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=352&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=442&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=442&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354685/original/file-20200825-24-1vlfw9t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=442&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Coloured perovskite light-emitting inks that can be cast down into thin films.</span>
<span class="attribution"><span class="source">© Sandeep Pathak</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Between <a href="https://www.nature.com/articles/d41586-019-01985-y">these and other companies</a>, there is rapid progress being made.</p>
<h2>Solar windows and flexible panels</h2>
<p>Unlike conventional silicon cells, which need to be very uniform for high efficiency, perovskite films are comprised of <a href="https://science.sciencemag.org/content/348/6235/683">mosaic “grains”</a> of highly variable size (from nano-meters to millimeters) and chemistry – and yet they perform nearly as well as the best silicon cells today. What’s more, small blemishes or <a href="https://www.nature.com/articles/s41586-020-2184-1">defects</a> in perovskite films do not lead to significant power losses. Such defects would be catastrophic for a silicon panel or a commercial LED.</p>
<p>Although we are still trying to understand this, these materials are forcing the community to rewrite the textbook for what we consider as an ideal semiconductor: they can have very good optical and electronic properties in spite of – or <a href="https://www.nature.com/articles/s41578-019-0125-0">perhaps even because of – disorder</a>.</p>
<figure class="align-center ">
<img alt="Light emitted from mosaic grains in a perovskite film" src="https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=481&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=481&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=481&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352239/original/file-20200811-18-1hh57dz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=605&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Light emitted from mosaic grains in a perovskite film.</span>
<span class="attribution"><span class="source">Dane deQuilettes/Sam Stranks</span></span>
</figcaption>
</figure>
<p>We could hypothetically use these materials to make “designer” coloured solar cells that blend in to buildings or houses, or solar windows that look like tinted glass yet generate <a href="https://www.youtube.com/watch?v=2ccar3uqWsw">power</a>. </p>
<p>But the real opportunity is to develop highly efficient cells beyond the efficiency of silicon cells. For example, we can layer two different coloured perovskite films together in a <a href="https://www.nature.com/articles/s41560-018-0190-4">“tandem” solar cell</a>. Each layer would harvest different regions of the solar spectrum, increasing the overall efficiency of the cell. </p>
<p>Another example is what Oxford PV are pioneering: adding a perovskite layer on top of a standard silicon cell, boosting the efficiency of the existing technology <a href="https://www.scientificamerican.com/article/perovskite-solar-cells-could-beat-the-efficiency-of-silicon/">without significant additional cost</a>. These tandem layering approaches could quickly create a <a href="https://pubs.rsc.org/en/content/articlelanding/2017/ee/c7ee01232b#!divAbstract">boost in efficiency</a> of solar panels beyond 30%, which would reduce both the panel and system costs while also reducing their <a href="https://cen.acs.org/energy/solar-power/Perovskite-solar-cells-score-highly/98/i30">energy footprint</a>.</p>
<p>These perovskite layers are also being developed to manufacture flexible solar panels that can be processed to roll like newsprint, further <a href="https://pubs.acs.org/doi/10.1021/acsenergylett.7b00964">reducing costs</a>. Lightweight, high-power solar also opens up possibilities for powering electric vehicles and communication satellites.</p>
<p>For LEDs, perovskites can achieve fantastic <a href="https://www.nature.com/articles/s41566-019-0543-y">colour quality</a> which could lead to advanced <a href="https://pubs.acs.org/doi/10.1021/acs.nanolett.8b04200">flexible display technologies</a>. Perovskites could also give cheaper, higher quality <a href="https://onlinelibrary.wiley.com/doi/10.1002/pssa.201800120">white lighting</a> than today’s commercial LEDs, with the “colour temperature” of a globe able to be manufactured to give cool or warm white light or any desired shade in between. They are also generating excitement as building blocks for <a href="https://science.sciencemag.org/content/363/6431/1068.abstract">future quantum computers</a>, as well as <a href="https://www.nature.com/articles/s41586-018-0451-1">X-Ray detectors</a> for extremely low dose medical and security imaging.</p>
<p>Although the first products are already emerging, there are still challenges. One key issue is demonstrating <a href="https://www.nature.com/articles/s41560-019-0529-5">long-term stability</a>. But the research is promising, and once these are resolved, halide perovskites could truly propel the transformation of our energy production and consumption.</p><img src="https://counter.theconversation.com/content/133658/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sam Stranks is a co-founder of Swift Solar, Inc.</span></em></p>
Halide perovskites are cheap, versatile and remarkably efficient as both solar cells and light emitters.
Sam Stranks, Lecturer in Energy and Royal Society University Research Fellow, University of Cambridge
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/129640
2020-01-15T17:54:56Z
2020-01-15T17:54:56Z
The pitfalls of eco-efficiency
<figure><img src="https://images.theconversation.com/files/309262/original/file-20200109-80159-15kaa41.jpg?ixlib=rb-1.1.0&rect=0%2C38%2C5184%2C3406&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Changing incandescent light bulbs (right) to LEDs (left) is an example of eco-efficiency, but it can also have unintended consequences.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?u=http%3A%2F%2Fdownload.shutterstock.com%2Fgatekeeper%2FW3siZSI6MTU3NDM3MjU2MSwiYyI6Il9waG90b19zZXNzaW9uX2lkIiwiZGMiOiJpZGxfMTExNjU3NDE4NCIsImsiOiJwaG90by8xMTE2NTc0MTg0L2h1Z2UuanBnIiwibSI6MSwiZCI6InNodXR0ZXJzdG9jay1tZWRpYSJ9LCJtcmNUWnZtUTM0d3JrZ2ZiY1lsYmhzL21RY2MiXQ%2Fshutterstock_1116574184.jpg&pi=33421636&m=1116574184&src=f6ac3cc3-e22c-4c3e-b3e1-39a9496c715f-1-51">Shutterstock</a></span></figcaption></figure><p>The saying “the road to hell is paved with good intentions” can be applied to many situations, and among them are companies’ efforts to preserve natural resources. For example, changes intended to reduce resource use can in the end have the opposite effect.</p>
<p>For a company, “eco-efficiency” means using fewer natural resources in the production process to obtain the same quality and quantity of a particular product. Coca-Cola and Nestlé, for example, strive to reduce their water use and Siemens is trying to use less electricity. This environmental effort is important, knowing that Coca-Cola needs 70 litres of water to produce 1 litre of soda and that they are responsible for considerable plastic pollution.</p>
<p>While “greener” products are very much in vogue, energy savings have the advantage of lowering production costs. Offering consumers products that are less resource intensive also sends out a positive signal. Let’s take a closer look at the mechanics of such an approach and how it can sometimes backfire.</p>
<h2>Rebound effects</h2>
<p>Many believe that an eco-efficiency approach aligns business’ economic objectives with the environmental objectives of reducing the use of natural resources. However, it is not that simple. We need to distinguish between the natural resources used per unit produced – often highlighted by companies engaged in an eco-efficiency approach – and the natural resources consumed overall, which are linked to global demand for these resources. It is this last point that determines the environmental impact.</p>
<p>For example, let’s examine the case of a car that is more fuel efficient, travelling more miles per gallon of gasoline. Less fuel is required to make the same trip, which also means that the same trip has now become cheaper. This money savings can encourage us to drive more, and therefore to consume more petrol – this is known as the “rebound effect”.</p>
<p>We observe the same effect for LED bulbs, which cost less to use than incandescent bulbs. We can make fewer efforts to turn off these low-consumption lights than those with incandescent bulbs, which can paradoxically can increase energy use.</p>
<p>By reducing production costs, eco-efficiency can thus have a “cost effect”: As production costs decrease, the selling price also decreases and, consequently, demand and production can rise. We consume more, which runs counter to our environmental objectives. This argument seems valid in mass markets. When total resource use increases as a result of an eco-efficiency policy, it is said that there is a “rebound”, with an ultimately negative impact on the environment.</p>
<h2>The case of luxury goods</h2>
<p>But there is also what we call a “negative rebound”, when resource use decreases more than expected. This is the case for luxury goods or niche markets, when companies use the green credentials of their products as a sign of differentiation. The consumer is then ready to pay more for greener products – for example for electric or hybrid cars or recyclable batteries. Today, hybrid cars are more expensive to produce than conventional ones, the process being relatively new and cost of development needing to be amortized. But at the same time, price is also higher because consumers are attracted to hybrid cars.</p>
<p>If companies take advantage of this and increase their prices, this results in a decrease in the quantities demanded and therefore in the total resources consumed. In the end, the environmental benefit is greater than expected. Paradoxically, it is when companies raise their prices for more eco-efficient products that the environmental impact will be most favourable.</p>
<p>To be genuinely beneficial to the environment, eco-efficiency policies must therefore not encourage demand too much and manage both the efficiency of resource use and the total amount of resources consumed. Such an holistic eco-efficiency management carefully balances the impact on price and demand, ensuring that good intentions become good environmental deeds.</p>
<hr>
<p><em>Stanko Dimitrov (Associate Professor at the University of Waterloo, Canada) and Frank Figge (Professor at Kedge Business School) contributed to this article.</em></p><img src="https://counter.theconversation.com/content/129640/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Régis Chenavaz ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>
Often presented as one of the best ways to save energy, eco-efficiency often proves to be less effective than one might think.
Régis Chenavaz, Enseignant-chercheur en économie et marketing, Kedge Business School
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/100345
2018-09-04T14:07:02Z
2018-09-04T14:07:02Z
How solar kits and battery lamps are replacing kerosene across Africa
<figure><img src="https://images.theconversation.com/files/233877/original/file-20180828-86120-12mug3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many rural communities across Africa have dropped kerosene lighting for various electrical lights.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>For decades, people in rural Africa have been using sooty kerosene lamps to dimly light their homes. But in recent years households, even in poor areas, have started to <a href="https://www.sciencedirect.com/science/article/pii/S0973082616310444">replace</a> their kerosene lamps with non-rechargeable dry-cell battery driven lamps and solar kits. This is happening largely without any governmental or donor involvement. These devices are equipped with light-emitting diodes (LED) that have become significantly <a href="https://www.mckinsey.com/%7E/media/mckinsey/dotcom/client_service/automotive%20and%20assembly/lighting_the_way_perspectives_on_global_lighting_market_2012.ashx">cheaper</a> over the years. This has, in turn, made them a highly efficient technology affordable, even for poor people living in rural areas. </p>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0973082616310444">study</a> covering seven countries across sub-Saharan Africa shows how privately supplied dry-cell battery driven lamps as well as solar kits have facilitated a lighting transition. Cheap supplies of disposable batteries and lamps mostly from China, have found their way into the most remote villages in the region. </p>
<p>A quote from a Senegalese expert we engaged with in the field summarises this transition:</p>
<blockquote>
<p><em>Chinese torches have electrified Africa, not World Bank.</em> </p>
</blockquote>
<p>At least for basic electric lighting provision this seems to be true. Obviously, LED torches do not replace the need for more powerful electricity that can be used for productive purposes.</p>
<p>The lighting transition away from kerosene is a remarkable development that challenges the traditional understanding of how mass electrification happens – and how mass adoption of a technology shapes up. The convention is that these processes are initiated from the top by governmental or non-governmental organisations supported by a development agent like the World Bank or its <a href="https://www.lightingglobal.org/">Lighting Global</a> programme, which specialises in supporting sustainable growth of the global off-grid lighting market. </p>
<p>But, in the case of dry-cell battery driven lamps, the technology has diffused without any top-down support. It’s an amazing tale of technology diffusion that has happened without any institutional support.</p>
<h2>The transition away from kerosene</h2>
<p>We came across an intriguing example in small villages in rural Rwanda we were surveying for a <a href="https://academic.oup.com/wber/article/31/3/631/2433616">randomised controlled trial on solar kits</a>. We found that people had replaced kerosene lamps with dry-cell battery LED lamps. Slightly better-off households were using ready-made flashlight – either smaller torches or much brighter multi-diode lamps. </p>
<p>Even the poorest people could afford the investment by hand-crafting one-diode torches, connected to disposable batteries tied by banana leaves. We were told by a number of people that kids had brought the idea from school, where it spread through word-of-mouth channels.</p>
<p>Admittedly, our lighting transition study covers only selected places in seven countries. But the similarity of these patterns across all of them suggests it can be generalised to other regions. </p>
<p>And the economic argument – affordability and scalability of LED-lamps – seems to be universal. LED torches are cheaper to run than kerosene lamps. In addition, the scalability from handcrafting dim one-diode lights (that come at less than a dollar) to bright multi-diode lamps (that can cost several dollars) solves the liquidity constraint problem attached to more lumpy investments. </p>
<p>LED seems to be a perfectly adaptive pro-poor technology. Households can scale the investment according to their ability to pay. Not least, rural dwellers everywhere have a high preference for LED over kerosene.</p>
<h2>How about quality?</h2>
<p>The concern of many donor agencies – including Lighting Global – is that the quality of these LED lamps and low cost solar lanterns is poor, particularly when it comes to their durability. Based on this assumption they advocate quality verified products.</p>
<p>Yet, in a case <a href="https://www.sciencedirect.com/science/article/pii/S1364032117315290">study</a> in Burkina Faso we showed that this is only true when one considers the absolute quality, not the quality relative to the upfront costs. For a household with low purchasing power it is not rational to invest in a high-quality kit that lasts, say, twice as long but costs three times as much. Given that poor people don’t have much cash and have many other urgent and essential things to deal with, it’s perfectly reasonable that they would prefer a cheaper solar lamp over a more expensive one – even if it breaks sooner.</p>
<p>This raises concerns about the inappropriate disposal of electronic waste. The shorter durability of non-quality-verified products and the surging consumption of dry-cell batteries in rural Africa is leading to more and more electronic waste. This increasing environmental burden needs to be addressed. Here, quality-verified solar kits and their licensed vendor network can have an important role, as we argue <a href="https://journals.openedition.org/factsreports/pdf/4222">in another paper</a>.</p>
<h2>Conclusion</h2>
<p>The LED dissemination success story has provided poor people in Africa with access to clean lighting sources. </p>
<p>This suggests that expectations about the impact of electrification have to be updated. Most notably, positive health effects by a reduction of kerosene induced air pollution as it was <a href="https://www.sciencedirect.com/science/article/pii/S0095069617304825">observed in El Salvador</a> might not materialise anymore in Africa. At the same time, policy makers should have an eye on an emerging new problem: the massive increase of electronic waste in areas were no waste management system is in place.</p><img src="https://counter.theconversation.com/content/100345/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jörg Peters has done consultancy work for foundations, bilateral and multilateral donor organizations such as World Bank, GIZ, 3ie, and Social Impact. He is affiliated with RWI - Leibniz Institute for Economic Research. His research group at RWI receives funding from the German Federal Ministry for Economic Affairs and Energy, the Ministry of Innovation, Science, and Research of the State of North Rhine-Westphalia, 3ie, and the Federal Ministry of Education and Research.</span></em></p>
A lighting revolution is underway across Africa that’s occurred largely without government or donor involvement.
Jörg Peters, Professor, University of Passau
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/99156
2018-07-02T17:47:38Z
2018-07-02T17:47:38Z
Graphene and the atomic crystals that could see next big breakthrough in tech
<figure><img src="https://images.theconversation.com/files/225738/original/file-20180702-116135-1nfm3nz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ready layer one. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/illustration-graphene-molecule-luminous-atoms-crystal-1026845797?src=UWnzYyZVG66GP5lzo-hoig-1-10">tschub</a></span></figcaption></figure><blockquote>
<p>What could we do with layered structures with just the right layers? What would the properties of materials be if we could really arrange the atoms the way we want them?</p>
</blockquote>
<p>The curious American physicist <a href="https://fs.blog/richard-feynman/">Richard Feynman</a> asked these questions in his landmark 1959 lecture, <a href="http://www.phy.pku.edu.cn/%7Eqhcao/resources/class/QM/Feynman%27s-Talk.pdf">There’s Plenty of Room at the Bottom</a>. It bustled with profound ideas about “manipulating and controlling things on the atomic scale”, using quantum mechanics. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=719&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=719&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=719&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=904&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=904&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225736/original/file-20180702-116139-52rp50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=904&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Atomic adventurer: Richard Feynman.</span>
<span class="attribution"><a class="source" href="https://it.wikipedia.org/wiki/File:Richard-feynman.jpg#/media/File:Richard-feynman.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Far-fetched at the time, now manipulating layers of atoms is a major research area. To realise Feynman’s vision, researchers at IBM and Bell Labs in the US had to devise a new approach to constructing materials layer by layer: <a href="https://warwick.ac.uk/fac/sci/physics/current/postgraduate/regs/mpagswarwick/ex5/growth/pvd/">molecular beam epitaxy</a> or MBE. </p>
<p>This can be likened to spray painting with atoms. You start by vaporising ultra-pure source materials like gallium, aluminium or indium, and combine them with the likes of arsenic or phosphorus. The vaporised atoms fly through a vacuum chamber towards a base layer made of similar materials. The atoms stick to it and slowly build up a crystal one atomic layer at a time. The ultra-high vacuum ensures impurities are minimal. </p>
<h2>Atomic architects</h2>
<p>While the process is relatively slow – typically only a few atomic layers per minute – the precision is remarkable. It allows technicians to stack different <a href="http://ethw.org/Semiconductors">semiconductor</a> materials on top of each other to create crystals known as <a href="https://theconversation.com/beyond-graphene-scientists-are-creating-an-atomic-lego-set-of-2d-wonder-materials-81709">heterostructures</a>, which can have extremely useful properties. By alternately stacking layers of aluminium arsenide and gallium arsenide, for example, you could produce a material that is extremely good at storing electricity. </p>
<p>Once this technique had been perfected in 1990s and 2000s, scientists were able to control the number of electrons and their energies in a particular crystal. And since light then interacts with these electrons, having more control over electron behaviour means you also gain more control of how they are stimulated by light. </p>
<p>Heterostructures have led to many new discoveries, particularly regarding the quantum behaviour of particles such as electrons within them. Nobel Prizes in Physics have been awarded five separate times (<a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1973/index.html">1973</a>, <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1985/index.html">1985</a>, <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1998/">1998</a>, <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2000/">2000</a>, and <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2014/">2014</a>), and the resulting materials have revolutionised civilisation. </p>
<p>Semiconductor heterostructures enable solar cells, LEDs, lasers and ultra-fast transistors. Even the internet would otherwise be impossible: the lasers which send the light pulses that encode the bits of information online are made from heterostructures, as are the photodetectors that measure these light pulses and decode the information.</p>
<p>There are restrictions, however. The atomic size, spacing and arrangement of these heterostructures cannot be too dissimilar between layers without defects arising. This limits the possible material combinations and the potential to freely engineer the electronic and optical properties. </p>
<p>Also, crystals naturally consist of atoms which form bonds in all three directions. This means there are always unsatisfied atoms with “dangling” bonds at the edges. Foreign impurities seek these bonds and create defects that can destroy other properties. This becomes especially important with smaller crystals, preventing them being integrated to their full extent into modern transistors, lasers and so forth. </p>
<h2>Enter 2D crystals</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=712&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=712&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=712&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=895&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=895&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225730/original/file-20180702-116123-e1wmih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=895&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graphene.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-illustration-graphene-material-molecular-grid-761990035?src=xMi-LIYHLvwuYH0jv2AyFQ-1-1">Olive Tree</a></span>
</figcaption>
</figure>
<p>The ultimate in ultra-thin sheets of materials is a single layer of atoms. Fortunately, nature devised such “two-dimensional crystals”. The most famous is <a href="https://theconversation.com/uk/topics/graphene-992">graphene</a>, which is just carbon atoms arranged in a hexagonal pattern. </p>
<p>Graphene is stronger than steel and conducts electricity better than copper. It has many unique and sometimes exotic electronic, optical and mechanical properties – as recognised by the <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2010/press.html">Nobel Prize in Physics</a> for its discovery in 2010. </p>
<p>In a perfect graphene crystal, all the atoms are completely bonded to one another and there are no dangling bonds. It is famously possible to produce graphene by peeling apart layers of graphite using scotch tape: graphite is actually many layers of graphene all held together by <a href="https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Intermolecular_Forces/Van_der_Waals_Forces">Van der Waals forces</a>, which are far weaker than the bonds in each constituent sheet of graphene. </p>
<p>Besides graphene, there are many other 2D crystals, each with unique properties. Several occur naturally as gems in the ground, such as molybdnimum disulphide, an important industrial lubricant. Others can be made by molecular beam epitaxy, such as the insulator boron nitride, and crystals in the same family of <a href="https://www.sciencedirect.com/science/article/pii/S1369702116302917">transition metal dichalcogenides</a> as molybdnimum disulphide. </p>
<p>Like graphene is to graphite, scientists “peel off” (or exfoliate) single 2D sheets from larger quantities of these compounds. The inherent thinness of these sheets means they can behave quite differently from the heterostructures described earlier. Different atomically thin materials can be insulating, semiconducting, metallic, magnetic or even superconducting.</p>
<p>Scientists are also able to pick, place and combine these materials at will to form new heterostructures, known as Van der Waals heterostructures, with different properties to the 2D sheets. Crucially, these don’t have the same limitations as their cousins made by molecular beam epitaxy. They can comprise layers of very different atomic crystals, enabling unprecedented and unlimited possibilities for combining different materials.</p>
<p>For example, you can combine magnetic layers with semiconductors and insulators without attracting contaminants like moisture or oxides between layers – impossible with epitaxial heterostructures. This can be used to create devices that control magnetism using electricity, which is the basis for magnetic memory in hard drives. </p>
<p>You can also stack together two identical atomic layers with one turned at an angle. This creates a lattice called a moiré pattern, which provides a new degree of freedom to engineer the electronic and optical properties. The images we are using to demonstrate this at the <a href="https://royalsociety.org/science-events-and-lectures/2018/summer-science-exhibition/exhibits/atomic-architects/">current Royal Society Summer Exhibition</a> in London give a flavour of how this works:</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=288&fit=crop&dpr=1 600w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=288&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=288&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=362&fit=crop&dpr=1 754w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=362&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/225919/original/file-20180703-116126-1b5pgj2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=362&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Moire power to your elbow.</span>
<span class="attribution"><span class="source">University of Heriot-Watt</span></span>
</figcaption>
</figure>
<p>While Van der Waals heterostructures are still in their infancy, impressive new physics and capabilities are already emerging. These include smaller, lighter, more flexible and more efficient versions of solar cells, LEDs, transistors and magnetic memory. </p>
<p>In future, we can expect surprises not previously dreamed of. An early example is the <a href="https://www.nature.com/articles/nature26160">recent discovery</a> that when you twist two layers of graphene at a “magic angle” relative to each other, the electrons become superconducting. This breakthrough, not clearly understood yet, could unlock 30-year-old mysteries of how electrons can navigate superconductors without losing any energy. It might allow us to use superconductors at room temperature, with potential benefits for everything from medical imaging and quantum computers to transmitting electricity long distances. </p>
<p>Predicting technological outcomes is not easy, however. As Herbert Kroemer, who shared the Nobel Prize in 2000 for developing semiconductor heterostructures used in high-speed and opto-electronics, <a href="https://www.ece.ucsb.edu/Faculty/Kroemer/pubs/11_03Speculations.pdf">often said</a>: </p>
<blockquote>
<p>The principal applications of any sufficiently new and innovative technology always have been and will continue to be applications created by that technology.</p>
</blockquote><img src="https://counter.theconversation.com/content/99156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Gerardot does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Layering substances like graphene in new ways could help us to build quantum computers or transmit electricity over long distances.
Brian Gerardot, Chair in Emerging Technologies, Heriot-Watt University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/89631
2018-01-09T22:22:28Z
2018-01-09T22:22:28Z
Improving upon the sun: LED lights fuel plant growth in space
<figure><img src="https://images.theconversation.com/files/201223/original/file-20180108-83547-sgjx71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Light-emitting diodes (LEDs) used in medical devices and for growing plants, like potatoes seen here, are used by NASA to grow plants in space. The U.S. space agency plans to grow food on future spacecraft and on other planets as a food supplement for astronauts. </span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>If you’ve ever seen the film <em>The Martian</em>, you’re familiar with “plants in space.” The protagonist in the film, played by Matt Damon, successfully harvests potatoes on Mars to feed himself when he’s stranded on the planet.</p>
<p>Far-fetched? Not at all. </p>
<p>Here at the University of Guelph in our Controlled Environment Systems Research Facility (CESRF), we’ve been investigating controlled-environment plant production and how best to get the most out of plants in terms of food, oxygen, fresh water and carbon dioxide scrubbing — in other words, human life support —for decades. Since the mid-1990s, we’ve been home to the Space and Advanced Life Support Agriculture (SALSA) program.</p>
<p>These research activities form Canada’s contribution to the niche field of space exploration known as <a href="https://motherboard.vice.com/en_us/article/43qd4q/this-biologist-wants-to-grow-vegetables-on-mars">“biological life support”</a> — or plants in space. </p>
<p>Research and technology developments in this field include:</p>
<ol>
<li>Biofiltration of indoor air (with terrestrial applications to mitigate “sick building syndrome”);</li>
<li>Disinfection methods that leave no toxic residue;</li>
<li>Ideal candidate crop selection as a source of food on long-term space exploration missions;</li>
<li>Reduced pressure studies to develop low-mass, inflatable “greenhouses” for the moon and Mars;</li>
<li>Environment control “recipes” for light, CO2, temperature, humidity, nutrients and water and, of course, a host of sensors of these environmental variables to facilitate plant growth.</li>
</ol>
<p>Among the more recent tools in the pursuit of high-density production of a range of crops are light-emitting diodes (LEDs) as a source of photosynthetic energy. In our research facility, we’re working to refine and perfect LED technology. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=903&fit=crop&dpr=1 600w, https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=903&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=903&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1135&fit=crop&dpr=1 754w, https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1135&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/201390/original/file-20180109-36019-2alqcb.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1135&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A prototype of a high-density modular plant production unit with genetically similar lettuce plants growing under three different light spectrum regimes (red, white and blue).</span>
<span class="attribution"><span class="source">University of Guelph, CESRF</span></span>
</figcaption>
</figure>
<p>The advent of ever-increasing intensity and efficiency of LEDs has expanded their use beyond cars and street lights. We now routinely consider LEDs as supplemental, or even sole-source, lighting for plants. </p>
<p>LEDs have a unique narrow wave band of light that represents a small sub-section of the solar spectrum. There are many examples of LEDs that virtually fill the spectrum of visible light and beyond to include ultraviolet bands and far-red to infra-red components. </p>
<p>We know quite a bit about how plants respond to various wavelengths, and certain combinations of wavelengths of light, based on research with filters and other more conventional lights that include high-pressure sodium, metal halide and fluorescent lighting. </p>
<h2>Improving upon the sun</h2>
<p>However, LEDs offer the opportunity to design a spectrum and assess the responses of plants to some very unusual colour combinations. </p>
<p>Among the suite of environmental variables that optimize plant production, the most powerful in determining just how a plant responds to its context is lighting. </p>
<p>Indeed, with the new attributes of LED lights, we can seemingly improve upon the sun in the production of various plant commodities.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/201389/original/file-20180109-36025-1rae0ib.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Results of lettuce plants grown under the three different light spectra showing differences in accumulated biomass and expressions of anthocyanin (pigment) in the leaves. These plants also tasted different, indicating additional secondary metabolite responses to the colour of the light.</span>
<span class="attribution"><span class="source">University of Guelph, CESRF.</span></span>
</figcaption>
</figure>
<p>The latest <a href="http://urbanagnews.com/blog/developing-the-right-light-recipes-for-greenhouse-vegetable-crops/">research findings</a> on various spectral qualities — colours, in other words — <a href="http://urbanagnews.com/blog/determining-the-potential-benefits-of-leds-on-plants/">provide details on specific responses</a> in some plants related to the plant’s size, shape and photosynthetic efficiency. We can even modify the content of metabolic compounds that influence the colour, taste and medicinal properties of a plant. </p>
<p>Those medicinal properties have attracted the scientific and industry communities in the evolving <a href="https://www.nutraceuticalsworld.com/issues/2016-10/view_columns/phytopharmaceutical-an-emerging-platform/">phyto-pharmaceutical</a> — medicines from plants — sector. </p>
<p>Low-cost production of reproducible, high-quality medicinal compounds is the main focus of the sector, and the range of commodities is growing rapidly. They include cancer drugs, vaccines for a range of viral pathogens, antibodies and, of course, cannabis or marijuana. Cannabis has a new-found status due to changes in laws <a href="https://globalnews.ca/news/3867467/marijuana-legalization-canada-progress/">in Canada</a> and elsewhere governing the use of this unique plant.</p>
<p>But these technologies, especially LED lights born in Canada’s space exploration research community, bring with them the responsibility to get it right — and the danger of getting it wrong is very real. </p>
<p>Early attempts in the recreational cannabis community a number of years ago when LEDs were deployed as a photosynthetic light source in efforts to reduce energy usage in basements and closets didn’t work so well. </p>
<p>It became obvious to those early pioneers growing cannabis under LEDs that something was amiss. The vague idea that some red and blue lights would do the job was quickly dispelled, but the stigma of those early failures still haunts the proponents of LEDs in that sector today.</p>
<h2>‘Refining recipes’</h2>
<p>We’ve come a long way since those missteps and misconceptions about how to use LEDs, but we have more work to do.</p>
<p>Researchers at the University of Guelph’s CESRF have been working with industry collaborators in the phyto-pharmaceutical sector (Plant Form Corporation), the medical cannabis sector (ABcann Medicinals Inc.), the LED sector (Intravision Light Systems) and the controlled environment sector (Conviron Ltd.) to refine recipes of environment control to grow plants for medicinal purposes.</p>
<p>We’re also working to develop the best management practices to serve these industry sectors and the Canadian public — as we seek to make the most of the latest technologies in controlled environment plant production.</p>
<p>And given U.S. President Donald Trump’s <a href="http://www.cnn.com/2017/12/11/politics/trump-astronauts-moon/index.html">recent comments about sending American astronauts back to the moon and Mars</a>, there’s every likelihood that we’ll get to test our “plants in space” expertise some time soon.</p><img src="https://counter.theconversation.com/content/89631/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Dixon receives funding from Natural Sciences and Engineering Research Council, Ontario Centres of Excellence, ABcann Medicinals Inc., PlantForm Corporation, IntraVision Light Systems Canada. </span></em></p>
LED lights can actually improve upon the sun and help grow plants in space. A Canadian team of researchers is helping to refine and perfect LED technology.
Michael Dixon, Professor and Director of the Controlled Environment Systems Research Facility, University of Guelph
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/87544
2017-11-15T14:42:33Z
2017-11-15T14:42:33Z
So much for COP23 – there’s a whole class of carbon emissions we’re totally ignoring
<p>“Further, faster ambition together” is the mission statement of the global leaders attending the <a href="https://cop23.unfccc.int">23rd Conference</a> of the Parties to the UN Convention on Climate Change (COP23) in Bonn. It has been met <a href="https://theconversation.com/five-things-that-should-happen-at-the-bonn-climate-talks-but-probably-wont-86560">with a mixture</a> of scepticism and urgency, particularly after the <a href="https://theconversation.com/five-things-that-should-happen-at-the-bonn-climate-talks-but-probably-wont-86560">new raised projections</a> for this year’s global carbon emissions suggested a peak has yet to be reached. </p>
<p>As part of the conference, cities and regions across the world are adopting the <a href="https://cop23.unfccc.int/news/cities-and-regions-adopt-bonn-fiji-commitment-on-climate-action">Bonn-Fiji Commitment</a> on climate action. It <a href="http://www.cities-and-regions.org/cop23/wp-content/uploads/2017/11/bonn-fiji-commitment-of-local-and-regional-leaders.pdf">aims to</a> remove up to 1.3 billion tons of CO₂ equivalent per year by curbing emissions at the local level. The <a href="http://www.coalitionforurbantransitions.org/home/news/newurbanleadershipcouncilaimstomakeeconomiccaseforbettercities">system</a> being <a href="http://www.worldbank.org/en/topic/climatechange/brief/city-climate-planner-certificate-program">put in place</a> to deliver the commitment does appear impressive, but look more carefully and it seems to see sustainable cities in very much the same way as usual: primarily cutting emissions from heat and transport and by installing more renewable energy. </p>
<p>This is all essential but it misses an important part of the picture. My main area of interest is the sustainability of buildings, a key component of reducing city emissions. For years, policies and regulations have focused on reducing the energy demands of buildings while we live, shop and work in them. As a result, the potential to reduce carbon in other stages of a building’s life has remained largely untapped.</p>
<h2>The big unsaid</h2>
<p>What I mean here is the carbon emissions involved in making, renovating and then eventually dismantling the building. This includes everything from mining the materials for the cement to chopping down the trees for the floorboards to transporting everything to the building site to digging the foundations; and then later from knocking the building down to disposing of its constituent parts. </p>
<p>We sometimes refer to the emissions while a building is functioning as the operational carbon, and all the other emissions across its life cycle as the <a href="https://www.sciencedirect.com/science/article/pii/S0301479716305746">embodied carbon</a>. Focusing on one and not the other is puzzling to say the least – we’re effectively trying to take the carbon out of our energy bills while paying no attention to the carbon in the buildings themselves. </p>
<p>While you can intervene along the way to improve the carbon emissions of a building’s energy use, there’s nothing you can do later about the emissions during construction. Not only that, interventions to improve a building’s energy efficiency actually make the total embodied carbon worse. </p>
<p>We rightly love insulation as a means of reducing a building’s heat requirement, but we install it with no regard for the carbon emissions produced in the process. And while, say, replacing fluorescent lighting with LEDs is an efficiency improvement that you can see, the carbon impact of the building will remain invisible until it has had an irreversible effect on the global environment. </p>
<p>The EU talks about <a href="https://ec.europa.eu/energy/en/topics/energy-efficiency/buildings/nearly-zero-energy-buildings">Nearly Zero Energy Buildings</a> (nZEBs) as the goal of its energy efficiency regulations. The closer it gets to this goal, the greater the share of the building’s environmental impacts when you look at carbon emissions overall. If we ever achieve nZEBs, embodied carbon will be the totality of emissions and it will be far too late to start worrying about it then. Even now, it can make up <a href="http://sturgiscarbonprofiling.com/wp-content/uploads/2010/05/RICS.RedefiningZero.pdf">as much as 90%</a> of the whole-life emissions on some buildings, while its share <a href="http://www.sciencedirect.com/science/article/pii/S0378778813004143?via%3Dihub">is growing</a> across the board. </p>
<h2>What to do</h2>
<p>So how to move forward? The most effective strategy is prevention, and a great deal can be done by designing our buildings with resource efficiency in mind. We tend to put much more materials into buildings than we need to – <a href="http://rspa.royalsocietypublishing.org/content/470/2168/20140170">steel being</a> a case in point. Buildings will still stand using much less steel, we just need to change the regulations. </p>
<p>There are <a href="https://www.sciencedirect.com/science/article/pii/S0301479716305746">also various other things</a> we can do: pre-manufacturing component parts under controlled industrial conditions is an important way of saving emissions. Sourcing materials closer to home needs to be taken more seriously, as does recycling materials from old buildings and using waste to help us build. A great example is the <a href="http://arts.brighton.ac.uk/business-and-community/the-house-that-kevin-built">Brighton Waste House</a> in the south of England, which showed for instance that you can fill cavity walls with everything from old clothes to videotapes. </p>
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<p>What this all requires is concerted and coordinated action from all the key stakeholders. Unfortunately, the COP23 Bonn-Fiji Commitment is only the latest initiative to essentially ignore this issue. Governments have <a href="http://www.sciencedirect.com/science/article/pii/S136403211730998X?via%3Dihub">broadly failed</a> to pass regulations around embodied carbon, and the topic is often relegated to the margins or completely ignored when it comes to policymakers’ <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/651148/20171005_-_Progress_report_response.pdf">sustainability agendas</a>. This is despite the fact that industry bodies and NGOs have actually led the way <a href="http://www.icevirtuallibrary.com/doi/pdf/10.1680/jensu.17.00032">by producing</a> a fair amount of guidance in this area. </p>
<p>Governments and other policy players are <a href="http://www.sciencedirect.com/science/article/pii/S136403211730998X?via%3Dihub">not even</a> managing to agree on how to undertake a whole-life carbon assessment. If they don’t do this accurately, we’re liable to end up with a gap between how much embodied carbon we think we are creating and how much ends up being released into the atmosphere. This, too, needs much more attention. </p>
<p>The whole problem is particularly relevant at a time when the Intergovernmental Panel on Climate Change <a href="http://www.ipcc.ch/pdf/assessment-report/ar5/syr/AR5_SYR_FINAL_SPM.pdf">is saying</a> there’s an urgent need to reduce carbon emissions sooner rather than later as it is too risky to rely on <a href="http://www.icevirtuallibrary.com/doi/pdf/10.1680/jensu.16.00020">yet unproven technologies</a> to save us at some point in the future. </p>
<p>Compared to some of the carbon reduction required to meet the commitments in the <a href="https://theconversation.com/what-will-the-world-actually-look-like-at-1-5-c-of-warming-68763">Paris Agreement</a> – weaning us off electricity from fossil fuels, say – focusing on the embodied carbon emissions in buildings is actually low-hanging fruit. It is time for policy people to step up their game and join the challenge while there is still time. And once they have tackled buildings they should start considering all the other embodied carbon emissions that they have been ignoring, too.</p><img src="https://counter.theconversation.com/content/87544/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Francesco Pomponi receives funding from the EPSRC. </span></em></p>
The CO2 we produce when we put up buildings is large and virtually unregulated.
Francesco Pomponi, Vice Chancellor's Research Fellow, Edinburgh Napier University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/81639
2017-07-27T15:04:44Z
2017-07-27T15:04:44Z
The scientific reason you don’t like LED bulbs — and the simple way to fix them
<figure><img src="https://images.theconversation.com/files/179991/original/file-20170727-8486-1sch1ar.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>There’s a handy trick for reading station signs that otherwise fly past in a blur as you travel in a high-speed train. Look at one side of the window and then immediately at the other side of the window. When you change your gaze, your eyes will automatically make a rapid jerking movement, known as a saccade. If the direction of the saccade is the same as that of the train, your eyes will freeze the image for a split second, long enough to read the station name if you time things right. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/books/NBK10991/">Saccades are</a> very fast movements of the eyes. Their exact speed depends on the size of the movement, but large saccades can move the eyes at the same rate as a high-speed train. The image of the station name becomes visible because it is travelling at the same speed as the eye, and the images before and after the saccade are blurred and so don’t interfere with the image of the sign. This shows us that our vision is still working when our eyes move rapidly during saccades. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180001/original/file-20170727-8492-y4e1h4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Blink and you’ll miss it.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Scientists used to think we could see no more than about 90 flashes of light a second but now we know <a href="https://www1.essex.ac.uk/psychology/overlays/2014-222.pdf">it’s more like 2,000</a> because the eyes move so rapidly when we change gaze from one point to another. During the eye movement, the flicker of light creates a pattern that we can see. And this has some surprising consequences for our health thanks to the way some types of lighting can affect us. In particular, it could discourage people from using more energy-saving LED lightbulbs.</p>
<p>Most lighting is electric and powered by an alternating current supply, which makes the bulbs continually dim and then brighten again at a very fast rate. Unlike filament lamps and to a lesser extent fluorescent lamps, LEDs don’t just dim but effectively <a href="https://www1.essex.ac.uk/psychology/overlays/2010-195.pdf">turn on and off completely</a> (unless the current is maintained in some way).</p>
<h2>Health concerns</h2>
<p>We know from earlier work on fluorescent lighting that even though the flicker is too fast to be visible, it remains a likely health hazard. In 1989, my colleagues and I compared fluorescent lighting that flickered 100 times a second with lights that appeared the same but didn’t flicker. <a href="https://www1.essex.ac.uk/psychology/overlays/1989-82.pdf">We found</a> that office workers were half as likely on average to experience headaches under the non-flickering lights.</p>
<p>No similar study has yet been performed for LED lights. But because LED flickering is even more pronounced, with the light dimming by 100% rather than the roughly 35% of fluorescent lamps, there’s a chance that LEDs could be even more likely to cause headaches. At best, it’s likely to put some people off using LED bulbs because of the annoying, distracting effect of the flickering, which we know can be detected during saccades.</p>
<p>One obvious way of avoiding the flicker is to operate the lamps with a direct current so the light is constant, but this involves <a href="http://ieeexplore.ieee.org/abstract/document/7070737/?reload=true">more expensive</a>, shorter-lived components. Another solution is to design the lights so that the flicker can’t be detected. But just how fast must the flicker be in order to be harmless?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180000/original/file-20170727-22996-1kd5bkc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">See the light.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>To find out, my colleagues and I asked people to make a saccade across a flickering source of light and to report when they could see a pattern of multiple images of the light during the eye movement. When the light flickered 1,000 times a second the pattern could clearly be seen. At about 3,000 per second, <a href="https://www1.essex.ac.uk/psychology/overlays/2013-207.pdf">the images became invisible</a>.</p>
<p>In contrast, some LEDs flash only 400 times per second. This flicker is still far too rapid to be seen directly, but some people can see multiple images of the lamps every time they make a saccade, which is unpleasantly distracting. The flickering of these LEDs may limit the uptake of the bulbs, just as many people <a href="http://www.huffingtonpost.com/frank-morgan/why-i-dont-like-energyeff_b_2047147.html">dislike energy-saving fluorescent lamps</a>.</p>
<p>When you buy an LED bulb, you currently have no way of telling whether or not it will flicker. But there are already <a href="https://standards.ieee.org/findstds/standard/1789-2015.html">standards for LEDs</a> that would limit flicker to acceptable levels. So ensuring these are met could make a big difference to our attempt to make our homes and workplaces more energy efficient.</p><img src="https://counter.theconversation.com/content/81639/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnold J Wilkins received funding from the Medical Research Council and the Wellcome Trust.</span></em></p>
That flicker in the corner of your eye isn’t your imagination.
Arnold J Wilkins, Professor of Psychology, University of Essex
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/75666
2017-04-21T11:59:44Z
2017-04-21T11:59:44Z
Scientists have worked out how dung beetles use the Milky Way to hold their course
<figure><img src="https://images.theconversation.com/files/164673/original/image-20170410-8855-epopod.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Insects navigate in much the same way that ancient humans did: using the sky. Their primary cue is the position of the sun, but insects can <a href="dx.doi.org/10.1007/s00114-004-0525-9">also detect properties of skylight</a> (the blue light scattered by the upper atmosphere) that give them indirect information about the sun’s position. Skylight cues include gradients in brightness and colour across the sky and the way light is polarised by the atmosphere. Together, these sky “compass cues” allow many insect species to hold a stable course.</p>
<p>At night, as visual cues become harder to detect, this process becomes more challenging. Some can use the light of the moon but one insect, the nocturnal dung beetle <em>Scarabaeus satyrus</em>, uses light from the Milky Way to orient itself. To find out exactly how this process works, my colleagues and I constructed an artificial Milky Way, using LEDs, to test the beetles’ abilities. <a href="http://rstb.royalsocietypublishing.org/content/372/1717/20160079">We found</a> that they rely on the difference in brightness between different parts of the Milky Way to work out which way to go.</p>
<p><em>Scarabaeus satyrus</em> holds its course with apparent ease every night. They take to the air at dusk in the African Savanna, in search of the fresh animal droppings on which they feed. But they are not alone and, to escape competition from other dung beetles, they construct a piece of <a href="https://books.google.com/books?isbn=1444341987">dung into a ball and roll it</a> a few meters away from the dung pile before burying and consuming it.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165831/original/image-20170419-6395-1dtpf5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Where am I supposed to take this thing?</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>To avoid returning to their starting point, they maintain a straight path while rolling their ball. Scientists discovered that the beetles could do this even on moonless clear nights. So in 2009, a group of researchers took some beetles on a trip to the <a href="http://www.planetarium.co.za">planetarium in Johannesburg</a>, and watched them try to orient themselves under different star patterns.</p>
<p><a href="http://bit.ly/2otpafg">They found</a> the beetles could hold their course well when the planetarium displayed just the Milky Way, the streak of light across the night sky produced by the disc-shaped arrangement of the stars in our galaxy. But the beetles became disoriented when only the brightest stars in the sky were shown.</p>
<p>What was still unclear was exactly what kind of compass cue the beetles extracted from the Milky Way. We knew, for example, that <a href="http://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/Soitec-Documents/Final-EIR-Files/references/rtcref/ch9.0/rtcrefaletters/F1%202014-12-19_Emlen1975.pdf">night-migrating birds learn the constellations</a> surrounding the sky’s northern centre of rotation, much as sailors did before the advent of modern navigation systems. These constellations remain in the northern part of the sky as the Earth rotates, and so are a reliable reference for north–south journeys.</p>
<p>The planetarium experiments had shown that the beetles don’t use constellations of bright stars, but perhaps they could learn patterns within the Milky Way instead. My colleagues and I then proposed that the beetles might perform a brightness comparison, identifying either the brightest point in the Milky Way or a brightness gradient across the sky that is influenced by the Milky Way.</p>
<h2>Artificial Milky Way</h2>
<p>We used our artificial night sky to test this theory, constructing <a href="dx.doi.org/10.1098/rstb.2016.0079">a simplified Milky Way streak</a> that simulated different patterns of stars and brightness gradients. We found that the beetles became lost when given a pattern of stars within the artificial Milky Way. The beetles only maintained their heading when the two sides of the streak differed in brightness. </p>
<p>This suggests nocturnal beetles do not use the intricate star patterns within the Milky Way as their compass cue, but instead identify a brightness difference across the night sky to set their heading. This is similar to what their <a href="dx.doi.org/10.1242/jeb.101154">day-active relatives</a> do when the sun is not visible but instead orient themselves using the brightness gradient of the daytime sky.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164663/original/image-20170410-8846-n7u3of.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Night-time compass.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This brightness-comparison strategy may be less sophisticated than the way <a href="dx.doi.org/10.%202307/4083330">birds</a> and human sailors identify specific constellations, but it’s an efficient solution to interpreting the complex information present in the starry sky—given how small the beetles’ eyes and brains are. In this way, they overcome the limited bandwidth of their information processing systems and do more with less, just as humans have learnt to do with technology.</p>
<p>This straightforward brightness comparison strategy is particularly effective over short distances. So although <em>Scarabaeus satyrus</em> is the only species known to hold its course in this way, the technique may also be used by many other nocturnal animals that perform short journeys at night.</p><img src="https://counter.theconversation.com/content/75666/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Foster receives funding from the Swedish Research Council, the Knut and Alice Wallenberg foundation, Carl Trygger's foundation for Scientific Research, the Lars Hierta Memorial foundation and the Royal Physiographic Society of Lund. </span></em></p>
New research shows the insects use the brightness of different stars to work out which direction to go.
James Foster, Postdoctoral fellow in functional zoology, Lund University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/61191
2016-06-17T19:48:57Z
2016-06-17T19:48:57Z
American Medical Association warns of health and safety problems from ‘white’ LED streetlights
<figure><img src="https://images.theconversation.com/files/127004/original/image-20160616-15101-15ih6si.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New LED-based streetlights are whiter than traditional ones and contain more blue light, which can disrupt people's circadian rhythms.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/meltedplastic/3907444366/in/photolist-6XhF5s-6XhDPN-84rvQK-6XdELi-nk8mKa-bozwY7-nX5Gjv-nX5Gpv-CYzzJ2-EdFbd-9MsGBc-9FRkyB-9nFzAm-ae6mBR-DsSjmc-w7qUJ3-DS4cc7-cjLNf1-7uxic1-6GAqUS-9ZJJKv-bEjMHE-92V95B-7JHUhR-88AaoS-9ZJGKC-9ZKbjw-9ZFPvT-9ZJGrE-9ZJwzj-5f51Pd-4MzuwD-8gBcuc-G15VgH-HRqKjg-HXPEqk-HRqJYg-H3323R-Cvn2CQ-5YBSnB-yvKfzC-uvesbh-vrGYfq-vaMZjx-uvesdG-uvesaA-vsAk5Z-vpWiuC-vaEw3w-vaMZhP">meltedplastic/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>The American Medical Association (AMA) has just adopted an <a href="http://www.ama-assn.org/ama/pub/news/news/2016/2016-06-14-community-guidance-street-lighting.page">official policy statement</a> about street lighting: cool it and dim it.</p>
<p>The statement, adopted unanimously at the AMA’s <a href="http://www.ama-assn.org/sub/meeting/">annual meeting</a> in Chicago on June 14, comes in response to the rise of new LED street lighting sweeping the country. An AMA committee issued guidelines on how communities can choose LED streetlights to “minimize potential harmful human health and environmental effects.”</p>
<p>Municipalities are replacing existing streetlights with efficient and long-lasting LEDs to save money on energy and maintenance. Although the streetlights are delivering these benefits, the AMA’s stance reflects how important proper design of new technologies is and the close connection between light and human health.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=649&fit=crop&dpr=1 600w, https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=649&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=649&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=816&fit=crop&dpr=1 754w, https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=816&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/127006/original/image-20160616-15101-9db9n8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=816&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Light is composed of light of different colors (red, blue and green) and some LED streetlights have a relatively high portion of blue light, which can disrupt people’s circadian rhythms.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/flakepardigm/3538195638">flakepardigm/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The AMA’s statement recommends that outdoor lighting at night, particularly street lighting, should have a color temperature of no greater than 3000 Kelvin (K). <a href="http://www.ies.org/lighting/science/color.cfm">Color temperature</a> (CT) is a measure of the spectral content of light from a source; how much blue, green, yellow and red there is in it. A higher CT rating generally means greater blue content, and the whiter the light appears.</p>
<p>A white LED at CT 4000K or 5000K contains a high level of short-wavelength blue light; this has been the choice for a number of cities that have recently retrofitted their street lighting such as <a href="http://crosscut.com/2013/03/streetlights-seattle-led/">Seattle</a> and <a href="http://www.nytimes.com/2015/03/24/nyregion/new-led-streetlights-shine-too-brightly-for-some-in-brooklyn.html?_r=0">New York</a>. </p>
<p>But in the wake of these installations have been complaints about the harshness of these lights. An extreme example is the city of Davis, California, where the residents demanded a <a href="http://volt.org/lessons-learned-davis-ca-led-streetlight-retrofit/">complete replacement</a> of these high color temperature LED street lights. </p>
<p>Can communities have more efficient lighting without causing health and safety problems? </p>
<h2>Two problems with LED street lighting</h2>
<p>An incandescent bulb has a color temperature of 2400K, which means it contains far less blue and far more yellow and red wavelengths. Before electric light, we burned wood and candles at night; this artificial light has a CT of about 1800K, quite yellow/red and almost no blue. What we have now is very different.</p>
<p>The new “white” LED street lighting which is rapidly being retrofitted in cities throughout the country has two problems, according to the AMA. The first is discomfort and glare. Because LED light is so concentrated and has high blue content, it can cause severe glare, resulting in pupillary constriction in the eyes. Blue light scatters more in the human eye than the longer wavelengths of yellow and red, and sufficient levels can <a href="http://www.sciencedirect.com/science/article/pii/S001448351400236X">damage the retina</a>. This can cause problems seeing clearly for safe driving or walking at night.</p>
<p>You can sense this easily if you look directly into one of the control lights on your new washing machine or other appliance: it is very difficult to do because it hurts. Street lighting can have this same effect, especially if its blue content is high and there is not appropriate shielding. </p>
<p>The other issue addressed by the AMA statement is the impact on human circadian rhythmicity.</p>
<p>Color temperature reliably predicts spectral content of light – that is, how much of each wavelength is present. It’s designed specifically for light that comes off the tungsten filament of an incandescent bulb. </p>
<p>However, the CT rating does not reliably measure color from fluorescent and LED lights.</p>
<p>Another system for measuring light color for these sources is called correlated color temperature (CCT). It adjusts the spectral content of the light source to the color sensitivity of human vision. Using this rating, two different 3000K light sources could have fairly large differences in blue light content.</p>
<p>Therefore, the AMA’s recommendation for CCT below 3000K is not quite enough to be sure that blue light is minimized. The actual spectral irradiance of the LED – the relative amounts of each of the colors produced – should be considered, as well.</p>
<h2>The reason lighting matters</h2>
<p>The AMA policy statement is particularly timely because the new <a href="https://theconversation.com/new-atlas-shows-extent-of-light-pollution-what-does-it-mean-for-our-health-60836">World Atlas of Artificial Night Sky Brightness</a> just appeared last week, and street lighting is an important component of light pollution. According to the AMA statement, one of the considerations of lighting the night is its impact on human health. </p>
<p>In previous articles for The Conversation, I have described how lighting affects our <a href="https://theconversation.com/a-dark-night-is-good-for-your-health-39161">normal circadian physiology</a>, how this could lead to some <a href="https://theconversation.com/the-mystery-of-breast-cancer-40036">serious health consequences</a> and most recently how <a href="https://theconversation.com/are-we-sleep-deprived-or-just-darkness-deprived-49412">lighting the night affects sleep</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/127156/original/image-20160617-11094-1evgmoc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">LEDs (the yellow device) produce a highly concentrated light, which makes glare a problem for LED streetlights since it can hamper vision at night.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/razor512/16600609643/in/photolist-rhWsTD-dE8A7B-yBCYNY-t5UGAN-bXWE3U-4p8H4S-iq3cH8-7wHEoe-4jiKuU-oMH3Dt-oMHC6C-4jZ4dv-p5cNgx-dEKPCn-7ijh4j-7wHCAe-6b8ts3-8aJ4av-cWTn5h-7wMpty-7wHFNM-atfx2A-atfxco-dSPin4-atfwQw-7LQwRU-4ow14n-4Kx9Vn-2qfzLE-4ow14g-4ovTrH-bpNru1-8Gr13D-4KxaTa-4ovTrP-2qfzLU-4Kx8Tz-7k9vW-4KS9bc-5oAF8A-96rBMt-7CGWT1-6dEsf7-qHxTX4-7gYKTE-oMHCeo-p3aVGG-oMHaAq-oMH9Jf-7TTyaN">razor512/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>In the case of white LED light, it is estimated to be <a href="http://www.sciencedirect.com/science/article/pii/S030147971100226X">five times more effective at suppressing melatonin</a> at night than the high pressure sodium lamps (given the same light output) which have been the mainstay of street lighting for decades. Melatonin suppression is a marker of circadian disruption, which includes disrupted sleep. </p>
<p>Bright electric lighting can also <a href="http://www.sciencedirect.com/science/article/pii/S0169534715001603">adversely affect wildlife</a> by, for example, disturbing migratory patterns of birds and some aquatic animals which nest on shore.</p>
<h2>Street lighting and human health</h2>
<p>The AMA has made three recommendations in its new policy statement:</p>
<p>First, the AMA supports a “proper conversion to community based Light Emitting Diode (LED) lighting, which reduces energy consumption and decreases the use of fossil fuels.”</p>
<p>Second, the AMA “encourage[s] minimizing and controlling blue-rich environmental lighting by using the lowest emission of blue light possible to reduce glare.”</p>
<p>Third, the AMA “encourage[s] the use of 3000K or lower lighting for outdoor installations such as roadways. All LED lighting should be properly shielded to minimize glare and detrimental human and environmental effects, and consideration should be given to utilize the ability of LED lighting to be dimmed for off-peak time periods.”</p>
<p>There is almost never a completely satisfactory solution to a complex problem. We must have lighting at night, not only in our homes and businesses, but also outdoors on our streets. The need for energy efficiency is serious, but so too is minimizing human risk from bad lighting, both due to glare and to circadian disruption. <a href="http://www.edisontechcenter.org/LED.html">LED technology</a> can optimize both when properly designed.</p><img src="https://counter.theconversation.com/content/61191/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard G. "Bugs" Stevens does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
The American Medical Association (AMA) issued guidelines for communities to reduce harmful effects of LED streetlights. A medical researcher explains what can go wrong.
Richard G. "Bugs" Stevens, Professor, School of Medicine, University of Connecticut
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/60847
2016-06-14T23:37:48Z
2016-06-14T23:37:48Z
22 ways to cut your energy bills (before spending on solar panels)
<p>Winter is here! Despite many Australians opting not to heat their homes to the point of complete comfort, many of us nevertheless will soon receive a nasty surprise when the energy bills arrive.</p>
<p>With Australia’s historically cheap energy, old housing stock in many areas, mild climate and frequent emphasis on low building costs, many homes are little more than “<a href="http://www.theage.com.au/comment/australian-houses-are-just-glorified-tents-in-winter-20150608-ghj2ox.html">glorified tents</a>” when it comes to thermal performance. </p>
<p>Besides wanting smaller bills, many residents also want to improve comfort, <a href="http://www.thefifthestate.com.au/arts-and-letters/how-to-wipe-out-household-energy-bills-in-9-steps/76854">lessen their environmental impact</a> and <a href="https://theconversation.com/energy-star-ratings-for-homes-good-idea-but-it-needs-some-real-estate-flair-54056">boost their home’s value</a>.</p>
<p>So here is a list of 22 things you can do to improve your home’s energy performance – some cheap, some free, and some that can even make you some money up-front as well as cutting your bills. Of course, to reach the ultimate goal of a home <a href="http://www.domain.com.au/news/welcome-to-victorias-most-sustainable-community-the-cape-at-cape-paterson-20151218-glno5i/">heated and powered by 100% renewable electricity</a> you may still wish to put some solar panels on your roof, but why not consider the following actions first?</p>
<p><strong>1. Make sure you get the <a href="https://www.energymadeeasy.gov.au/">maximum discount</a></strong> on your energy bills. Although not available everywhere, in Victoria discounts of up to 38% are available on gas or electricity. Ring up your retailer and just ask, or threaten to switch, or better yet seek out a retailer that doesn’t treat their discounts like <a href="http://www.powershop.com.au/toolkit/">state secrets</a>.</p>
<p><strong>2. Monitor your power usage</strong> with the help of a <a href="http://www.smartmeters.vic.gov.au/interactive-devices">“smart” electricity meter or in-home electricity display</a>. This real-time (or near-real-time) information is more useful than the coarse monthly data commonly printed on energy bills. It can help identify appliances that have inadvertently been left on or those that draw excessive power when not in use.</p>
<p><strong>3. Heat your water off-peak</strong>. If you have a resistive-electric hot water storage tank, make sure it heats up at night, when off-peak power rates apply. In some areas, “<a href="http://switchon.vic.gov.au/bills-pricing-and-meters/flexible-pricing">time of use</a>” rates are available.</p>
<p><strong>4. Get rid of your ‘garage fridge’</strong>. It can cost hundreds of dollars a year to run an <a href="https://www.washingtonpost.com/news/wonk/wp/2014/11/26/why-its-not-okay-to-have-a-second-refrigerator/">inefficient 20-year-old fridge</a>, especially if it’s in a garage that hits 50°C in summer.</p>
<p><strong>5. Ditch your super-hot plasma</strong>. If you have a <a href="http://www.sustainability.vic.gov.au/services-and-advice/households/energy-efficiency/at-home/appliances/tvs-and-home-entertainment-systems">10-year-old television</a> that gets so hot you can fry an egg on the screen, check out the newer models that can use <a href="http://reg.energyrating.gov.au/comparator/product_types/32/search/">one-tenth of the electricity</a>.</p>
<p><strong>6. Install a modern showerhead</strong>, such as those designed with <a href="http://pure-electric.com.au/products/methven-kiri-satinjet-ultra-low-flow-4.5-litre">double-impinging jet technology</a> that use only 5 litres of water per minute. Old showerheads can pass up to 35 litres per minute. Why not grab a bucket and stopwatch and test yours?</p>
<p><strong>7. Insulate any exposed hot water pipes</strong>, including the <a href="http://www.valvecosy.com.au/">pressure-relief valve on your hot water tank</a>. Make sure hot water pipes do not <a href="http://mei.insights4.net.au/switching-gas-report-available-here">run uninsulated straight into the soil</a> in your garden. <a href="https://sites.google.com/site/homeenergyefficiencyresource/home/hot-water-cylinder-work/increase-insulation-of-existing-hot-water-cylinder">Insulate electrically heated storage tanks</a> where it is safe to do so.</p>
<p><strong>8. Check your heaters and air conditioning</strong>. Gas heating systems should be checked at least every two years by a qualified person, not least to keep <a href="http://www.esv.vic.gov.au/For-Consumers/Gas-and-electrical-safety-in-the-home/Gas-safety-in-the-home/Heating-your-home-safely-with-gas">poisonous carbon monoxide gas</a> at bay. All heating or cooling system filters should be cleaned regularly to improve energy efficiency and air quality.</p>
<p><strong>9. Inspect your ducts</strong>. Poorly installed or degraded ductwork can lead to big energy losses, which can go unnoticed for decades. Ensure that small children or animals have not gone under your house and damaged your gas heating ducts. Check also that air returns are properly “boxed-in” and do not draw air in from the wall cavity instead of from the living space. However, cleaning the inside of your ducts is not critical for energy saving, and risks damaging them in the process.</p>
<p><strong>10. <a href="http://passivehouse.com.au/page/blower-door-testing">Banish drafts</a></strong>, for instance by plastering over those ubiquitous <a href="http://www.hobsonsbay.vic.gov.au/files/f66b552b-d808-43b8-b55c-a41e00e00c4e/Blocking-Draughts-FAQ.pdf">wall vents</a> – relics from the days when homes relied on unflued heaters or gas lights. Seal off unused chimneys and fill any other cracks, gaps or holes around <a href="http://ecomasterstore.com.au/products/draughtdodgers-for-doors">doors</a>, windows, skirting boards, floorboards and architraves. Remember to close air-conditioning ceiling vents in winter. Ventilation should be controlled by opening windows, not by having permanent holes in the walls.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/126475/original/image-20160614-29222-124i05b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Older houses can be full of drafts, including from wall vents which are a throwback to times when homes were full of indoor pollution.</span>
<span class="attribution"><span class="source">Bidgee/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><strong>11. <a href="http://efficiencymatrix.com.au/our-videos/">Eliminate ceiling-mounted downlights</a></strong> wherever possible. A small number of modern wide-beam LEDs can adequately replace a larger quantity of narrow-beam halogen downlights. Aim to have as few holes cut into your ceiling as possible, because these holes let heat escape in winter and let it in during summer.</p>
<p><strong>12. Install <a href="https://shop.ata.org.au/shop/led-downlight-insulating-cover">downlight covers</a></strong> over all downlights that protrude into accessible attic spaces. Not only does this reduce <a href="http://www.fire.nsw.gov.au/page.php?id=709">fire hazards</a> and keep out insects, but it will also reduce air flow through the roof.</p>
<p><strong>13. Replace all regularly used lights with LEDs</strong>. LEDs use a tenth of the energy of halogen or incandescent bulbs, so will pay for themselves in just a few months (even less in places where <a href="http://www.sustainability.vic.gov.au/services-and-advice/households/energy-efficiency/toolbox/how-to/replace-12-volt-halogen-downlights">free replacement</a> is on offer). Replace less regularly used bulbs with LEDs as and when they burn out, and vow never to buy a non-LED bulb again.</p>
<p><strong>14. Insulate your attic…</strong>. If you don’t have roof insulation, buy some. If you do, check it meets the recommended “<a href="http://www.yourhome.gov.au/passive-design/insulation">R value</a>” for your climate. Ensure all vertical attic surfaces (walls, skylight tunnels) are also insulated, and include a <a href="http://www.thefifthestate.com.au/innovation/building-construction/insulation-how-to-make-the-right-decision/72343">layer of aluminium</a> in your attic space. <a href="http://www.ata.org.au/wp-content/uploads/Thermal-Imaging-Presentation.pdf">Thermal imaging</a> can be used to identify existing flaws, such as gaps or sections of insulation inadvertently moved by tradespeople working in the attic. </p>
<p><strong>15. …and your floors and walls too</strong>. In cooler Australian climate zones, <a href="http://www.ecomaster.com.au/what-is-underfloor-insulation/">floor</a> and wall insulation can help keep heat in, making your home warmer and cheaper to operate.</p>
<p><strong>16. Cover your windows from the inside…</strong> with drapes, curtains or blinds. This will keep in heat at night and on cold winter days, and keep out the sun in summer. Cheaper or do-it-yourself thermal window treatments such as plastic films or even bubble wrap can be applied in some situations (just don’t expect to win any design awards).</p>
<p><strong>17. …and the outside</strong>. Trees, plants, external awnings, blinds or shade sails can all keep out the summer sun and stop windows getting hot. Remember that <a href="http://www.ata.org.au/wp-content/uploads/Thermal-Imaging-Presentation.pdf">significant heat will reflect</a> onto windows from sizzling decks, paved areas and walls (but not lawns). It’s better to keep out the sun in the first place rather than try to cool your house down.</p>
<p><strong>18. Double glazing</strong> for windows cuts out noise, improves security and <a href="https://www.ata.org.au/news/atas-new-green-home-heating-e-book">saves energy too</a>. For many Australian climate zones, I recommend that homeowners never buy a window in future that isn’t double-glazed. <a href="http://www.diydoubleglaze.com.au/ATA.pdf">Retrofit options</a> options such as “secondary glazing” are also available.</p>
<p><strong>19. Fit a pool cover</strong> if you have a swimming pool. Not only will this stop the water cooling down overnight in summer, but a cover can also minimise cleaning, chemical use and the running time for your filter pump. Consider upgrading to a <a href="http://www.energyrating.gov.au/products/swimming-pool-pumps">more efficient pump</a> if yours is more than a decade old, and ensure it does not run for more hours each day than required.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/126477/original/image-20160614-17209-1doru8y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Remember to cover up when not sunbathing.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3ABackyard_swimming_pool_in_Queensland.JPG">Kgbo/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><strong>20. Use reverse-cycle to heat your home…</strong>. If your home has <a href="https://theconversation.com/hot-summer-nights-and-cold-winter-evenings-how-to-be-comfortable-and-save-money-all-year-long-51046">reverse-cycle air conditioning (also known as a heat pump)</a>, this may be the cheapest way to heat, especially as <a href="https://theconversation.com/its-cold-in-my-house-and-the-price-of-gas-is-going-up-what-can-i-do-44824">gas prices rise</a>. On heat mode, reverse-cycle units harvest <a href="https://theconversation.com/the-cheapest-way-to-heat-your-home-with-renewable-energy-just-flick-a-switch-47087">free renewable ambient heat from the air outside your home</a> and pump it up to the toasty temperature you need inside. Having installed high-efficiency reverse-cycle units, I can heat my own home for <a href="http://renew.org.au/articles/comfortably-ahead-a-tale-of-two-heaters/">one-third of the cost</a> of ducted gas heating.</p>
<p><strong>21. …and your water</strong>. If your hot water system is nearing its use-by date, consider replacing it with a heat pump. This is an especially good option for homes that already have <a href="https://theconversation.com/get-more-out-of-your-solar-power-system-by-using-water-as-a-battery-37807">solar panels and low feed-in tariffs</a>.</p>
<p><strong>22. If you can <a href="http://energyfreedom.com.au/">eliminate all gas use</a></strong> in your home (for <a href="http://mei.insights4.net.au/switching-gas-report-available-here">space heating, water heating and cooking</a>), you can eliminate your gas bill with its nearly A$1 per day fixed supply charges.</p>
<h2>And then there is solar…</h2>
<p>In Australia these days, you won’t be paid much money for selling your electricity back to the grid. However, it might still pay to install solar if you can <a href="http://reneweconomy.com.au/2015/solars-inconvenient-truth-its-all-about-self-consumption-19817">consume most of the energy yourself</a>, by running your pool pumps, appliances, space heating and cooling devices, hot water system and even an electric car with solar electricity harvested during the day. </p>
<p>In future, as <a href="https://www.ata.org.au/news/grid-connected-batteries-economically-attractive-by-2020-ata-report">electricity storage batteries get cheaper</a>, there may be even more economic reasons to have solar panels on your roof.</p>
<p>This article doesn’t list every possible <a href="http://www.thefifthestate.com.au/politics/local-government/how-gamification-is-saving-brisbane-renters-thousands-on-energy-bills/82684">behavioural trick</a> or <a href="http://www.yourhome.gov.au/">home improvement</a>. Sadly, some homes will never be fantastic energy performers without significant modification. But hopefully there are a few things on this list that will work for you – even if it’s only a case of finally covering that drafty doorstep, or giving your creaking “beer fridge” a dignified retirement.</p><img src="https://counter.theconversation.com/content/60847/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>In addition to his role at the University of Melbourne, Tim has conducted over 400 home energy assessments/consultations working or volunteering with organisations such as the not-for-profit Moreland Energy Foundation - Positive Charge.</span></em></p>
There are loads of things you can do to cut your energy bills - and many don’t involve stumping up any cash up-front at all.
Tim Forcey, Energy Advisor, Melbourne Energy Institute, The University of Melbourne
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/57404
2016-06-13T13:28:10Z
2016-06-13T13:28:10Z
Why you should get ready to say goodbye to the humble lightbulb
<figure><img src="https://images.theconversation.com/files/126293/original/image-20160613-29205-1gffexx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">University of Bath</span></span></figcaption></figure><p>Lightbulbs are disappearing. The traditional incandescent bulbs that revolutionised daily life in the 20th century have largely already gone and the energy efficient fluorescent bulbs that replaced them are now also on their way out. In their place, we now have highly efficient light emitting diodes (LEDs), which are small semiconductor devices that produce light when an electric current is passed through them.</p>
<p>But even these are often arranged in a device that looks something like a conventional lightbulb. The technology that comes next could do away with the concept of rooms having a single light source and instead build light into ceilings and walls. This new type of organic LED (OLED) will redefine how we think about lighting.</p>
<p>OLEDs are not bulbs but films of layered organic semiconductors, meaning that they are made from carbon and hydrogen, just like organic life. There are <a href="http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=19353440">two main families</a> of OLED: those based on small molecules and those employing polymers. Organic LEDs aren’t connected to organic food or farming but they are very efficient and do not contain toxic metals, such as mercury, so they are a <a href="http://www.sciencedirect.com/science/article/pii/S1369702112701396">green technology</a>.</p>
<p>Conventional LEDs produce sharp points of light and cannot produce white light so LED bulbs usually mix different colours to approximate natural light but often do so with a blue tinge. In contrast, OLEDs emit a soft, diffuse light that’s colour can be tuned to mimic natural light as closely as the old incandescent lamps. The technology provides fast switch-on times, wide operating temperatures and no noise. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=472&fit=crop&dpr=1 600w, https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=472&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=472&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=593&fit=crop&dpr=1 754w, https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=593&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/126297/original/image-20160613-29238-13yynom.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=593&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Alison Walker and colleague Enrico Da Como experimenting with OLED panels.</span>
<span class="attribution"><span class="source">University of Bath</span></span>
</figcaption>
</figure>
<p>But perhaps the most interesting thing about OLEDs is that the films they are made from are just 0.3mm wide and can be moulded into flexible, transparent lighting panels and twisted into different shapes. This means OLED lights won’t just be small fittings placed in the middle of a ceiling. Instead, they can be made in a variety of sizes and shapes and fitted to different parts of a room, or even used to create animated screens or <a href="http://www.cnet.com/uk/news/lg-displays-latest-oled-tv-sticks-to-the-wall-is-under-1mm-thick/">wirelessly updatable wallpaper</a>.</p>
<p>It also means they could be made using <a href="http://semimd.com/blog/tag/oleds/">additive manufacturing</a> processes – essentially printing the entire technology onto a wall or ceiling panel or other flexible base. This would reduce waste because you only print what you need and you can manufacture the lights locally, reducing their environmental impact. They also don’t require the high temperature curing ovens used to make conventional LEDs.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/1Fij_own6jg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>An <a href="http://www.explainthatstuff.com/how-oleds-and-leps-work.html">OLED lighting panel</a> comprises multiple layers of organic material that are each tens of nanometers thick. These are sandwiched between two electrodes, a transparent conducting base layer and a metallic top layer. When electricity passes between these electrodes, it causes the organic material in between to emit light. Certain organic molecules in the layers act as “dopants” which determine the wavelength and so the colour of the light.</p>
<h2>Bringing the cost down</h2>
<p>Despite all the advantages of OLEDs, it may still take a while for them to take over from existing light fittings. The main reason we don’t already have OLEDs in our homes is the price tag. <a href="http://www.inter-lumi.com/m_article/16-At-what-price-consumers-will-adopt-OLED-lighting.html">Industry experts</a> expect OLED lighting will become a major market by 2020-2023, when OLED panels are expected to cost €200 per square metre (down from €7,000 today).</p>
<p>Cheaper OLEDs should be made possible by developing faster manufacturing methods. <a href="http://www.techhive.com/article/3018446/smart-tv/oled-vs-led-theres-just-no-comparison.html">We also need</a> to find a way to ensure the blue light emitting molecules in OLEDS last as long as those that produce green and red emissions. OLEDWorks, a New York-based lighting company that bought the OLED division from Philips Lighting in 2015, already has <a href="http://electronicdesign.com/leds/oled-lighting-flickers-through-growing-pains">several products</a> with 50,000-hour lifespans – comparable to existing LED lights. Once these goals are achieved we should be prepared for any part of a room – or object within it – to light up when we flick the switch.</p><img src="https://counter.theconversation.com/content/57404/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alison Walker receives funding from the European Union Horizon 2020, H2020, research and innovation programme for the project Extmos, EXTended Model of Organic Semiconductors under grant agreement 64617, and the Seventh Framework Programme Initial Training Network Destiny, DyE SensiTIzed cells with eNhanced stabilitY under grant agreement 316494 both of which she coordinates. In addition she is funded by the H2020 Energy Oriented Centre of Excellence, EoCoE under grant agreement 676629. She is also funded by the UK Engineering and Physical Sciences Research Council Centre for Doctoral Training in New and Sustainable Photovoltaics (which she coleads), the Supersolar hub, and Doctoral Training Award studentships and by the University of Bath for studentships.</span></em></p>
Flexible light-emitting screens mean you soon won’t need bulbs because your wallpaper – or even your furniture – will light up at the flick of a switch.
Alison Walker, Professor of physics, University of Bath
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/35934
2015-01-13T10:28:17Z
2015-01-13T10:28:17Z
Light technologies illuminate global challenges
<figure><img src="https://images.theconversation.com/files/68735/original/image-20150112-23795-1y2yua4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Light of every hue.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/puuikibeach/8379040816">davidd</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>During these dark winter months, spare a thought for artificial lights. From strings of lights adding holiday cheer to artificial sunlamps alleviating seasonal affective disorder, they brighten our days. And light’s applications can go much further than that. The United Nations designated 2015 as the <a href="http://www.light2015.org/">International Year of Light and Light-Based Technologies</a> to raise awareness of how photonic technologies offer solutions to international challenges. Light technology is now an active area of research in energy, health and agriculture.</p>
<h2>First lighting the way</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=828&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=828&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=828&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1041&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1041&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68731/original/image-20150112-23804-1a3k0h0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1041&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Thomas Edison with some of his incandescent bulbs.</span>
</figcaption>
</figure>
<p>In the late 1800s, Thomas Edison created a practical light bulb, an electrically-powered, long-lasting light source that significantly changed our work, play and sleep habits. The ability to control light in new ways transformed how we experience and see the world. Light-based technologies such as optical fiber networks allow us to connect rapidly with people worldwide over the internet. Light emitting diodes (LEDs) are now everywhere from consumer electronics like smart phones to light bulbs for home lighting.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68718/original/image-20150112-23792-crwkn6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">CoeLux’s artificial skylight harnesses technology to mimic our most vital light source: the sun.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/hllwy/16056183572">James Holloway</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>One recent example is the artificial skylight invented by researchers who spent over ten years refining the <a href="http://www.coelux.com/">CoeLux</a> system. This invention, which received <a href="http://luxreview.com/news/498/lux-awards-2014-the-winners">Lux Awards 2014</a> Light Source Innovation of the Year, can fill a room’s ceiling mimicking sunlight from different latitudes, from the equator to northern Europe. The key to its success in replicating a sunny sky uses nanostructured materials to scatter light from LEDs in the same way tiny particles scatter sunlight in the atmosphere – so-called Rayleigh scattering. Funding for this project from the European Commission enabled scientific advances in light management and nanotechnology as well as the completion of a device that may improve quality of life in indoor settings, from hospitals to underground parking garages.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68734/original/image-20150112-23812-deuif.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blue LEDs were the missing link.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/psychlist1972/5894900905/">Pete Brown</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Illuminating research</h2>
<p>Only recently has the full utility of LEDs been realized for general lighting. While red and green LEDs had been in commercial use for more than a decade, the missing color for producing white light was blue. Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura cracked the blue conundrum in the early 1990s. Now, thanks to their work, white light LEDs are ubiquitous. In recognition of this energy-saving invention, they received the Nobel Prize in <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/">Physics</a> last year.</p>
<p>Light was also recognized in the Nobel Prize category of <a href="http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2014/">Chemistry</a> last year for light-based microscopy tools that use a few tricks to sense the presence of a single molecule. Microscopy had been limited by diffraction, where two adjacent objects can only be resolved if they are separated by more than half the wavelength of light used for imaging. But Nobel laureates Eric Betzig, Stefan Hell and W.E. Moerner all took different approaches using similar principles to get beyond the diffraction barrier in order to control the fluorescence of individual molecules to view them in high detail. By turning the light emitted from the molecules on or off, the scientists could reconstruct the location of the molecules at the nanometer scale.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=299&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=299&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=299&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68749/original/image-20150112-23812-1rzs0uw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscope images of human protein vimentin. Note the higher resolution on the right.</span>
<span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:STED_microscopy_image_of_Vimentin_with_25nm_resolution.jpg">Fabian Göttfert, Christian Wurm</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Here’s how it works: a fraction of fluorescent molecules or proteins is first excited by a weak light pulse. Then after their emission fades, another subgroup of fluorescent molecules are excited. This cycle of on and off continues, and then the images are processed and superimposed to form a high-resolution map of individual proteins. The ability to peer into the nano-world of living cells to observe, for example, how proteins aggregate in the earliest stages of diseases like Alzheimer’s and Huntington’s, has just begun. Understanding disease progression at the single-molecule level could help identify when early intervention might be advantageous. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68725/original/image-20150112-23786-s9wx59.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Let there be light in the darkness.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/martinaphotography/6420386691">martinak15</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Investors must see the light</h2>
<p>Light is a unifying science across fields like chemistry and physics, improving our lives and the world. But learning how to manipulate light is costly and takes time. Technologies are largely built on investments in basic science research as well as, of course, serendipity and circumstantial opportunities. Take LEDs for example. <a href="http://spectrum.ieee.org/tech-talk/geek-life/history/rcas-forgotten-work-on-the-blue-led">Research in blue LEDs</a> started more than 40 years ago at Radio Corporation of America, but changes in the company’s funding structure stymied their development for two decades — until last year’s Nobel Prize winners solved the materials problem and the scale-up process. </p>
<p>Continued and sustained support of fundamental research is critical for future technologies not yet imagined or seen but that could have a transformative impact on our daily lives. For example, in agriculture, more effective harvesting of solar energy and its conversion into heat via greenhouses could enable year-round production as well as access to crops not currently available in certain climates.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=234&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=234&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=234&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=294&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=294&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68746/original/image-20150112-23786-1p5wnhk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=294&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">(Left) Cartoon of nanoparticle lasers. (Right) Electron microscopy image of an array of bow-tie nanolasers.</span>
<span class="attribution"><span class="source">Teri Odom</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In my own work as a chemistry researcher, my group invented a <a href="http://dx.doi.org/10.1021/nl303086r">laser the size of a virus particle</a>, which should not be possible based on traditional ways to control light but is, thanks to metal nanoparticles that can squeeze light into small volumes. These tiny lasers are promising light sources that can be used to send and receive data with high bandwidths as well as to detect trace molecules or bio-agents.</p>
<p>Construction of our nano-laser required precise control over the shape and location of the adjacent gold nanoparticles. That such nanostructures could even be made is because of the decades-long investment by the electronics industry in developing nanofabrication tools to make the tiny components in computers. Investments in both fundamentals and applications are critical, as has been highlighted by last year’s Nobel Prizes in Chemistry and Physics.</p>
<p>The UN’s designation of this International Year of Light will spotlight the potentials of these kinds of innovations and the need to continue investing in future technologies. From new ways to shake off those winter blues to manipulating light in small spaces, the trajectory for artificial light is bright indeed.</p><img src="https://counter.theconversation.com/content/35934/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Teri Odom receives funding from the National Science Foundation.</span></em></p>
During these dark winter months, spare a thought for artificial lights. From strings of lights adding holiday cheer to artificial sunlamps alleviating seasonal affective disorder, they brighten our days…
Teri Odom, Professor of Chemistry, Northwestern University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/32456
2014-10-07T14:40:20Z
2014-10-07T14:40:20Z
Your phone screen just won the Nobel Prize in physics
<p>You’ve probably got the fruits of this year’s Nobel laureates’ handiwork in your pocket. In fact, if you’re reading this on your phone or a relatively recent flat-screen monitor, you’re more than likely staring at some of them right now.</p>
<p><a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/">The 2014 Nobel Prize in physics</a> has been awarded to <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/akasaki-facts.html">Isamu Akasaki</a>, <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/amano-facts.html">Hiroshi Amano</a> and <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/nakamura-facts.html">Shuji Nakamura</a> for their pioneering work on blue LEDs, or light-emitting diodes. Blue LEDs are important for two reasons: first, the blue light has specific applications of its own and second, because it’s a vital component of the white light which makes white LEDs, and therefore LED computer and phone screens, possible.</p>
<h2>A flash of inspiration</h2>
<p>So, what is an LED? Fundamentally, the simplest LEDs are two pieces of <a href="http://en.wikipedia.org/wiki/Semiconductor">a semiconductor material</a> sandwiched together. Semiconductors, as their name suggests, are materials which don’t conduct electricity all that well.</p>
<p>This property might seem to demarcate them as thoroughly unremarkable, but in fact this propensity for unimpressive transmission of electrical currents has a huge advantage to technologists: its flexibility. If you take a semiconductor – silicon, for example – and mix in tiny amounts of impurities during manufacture, you can radically alter its electrical properties.</p>
<p>The two broad types of semiconductor you can make are called n-type and p-type. To make an n-type semiconductor, the impurity you add needs to be something which has lots of electrons. This gives the semiconductor an excess of electrons, and makes it a slightly better conductor of electricity.</p>
<p>A p-type semiconductor is the opposite: you add a chemical element which has a deficiency of electrons compared to the semiconductor around it, and you end up with an excess of “holes” – missing electrons, stolen from the semiconductor by the impurities you’ve added. (Counter-intuitively, this also increases the conductivity, because these holes can carry current too!) But it’s when you stick n-type and p-type together that the real magic happens. </p>
<p>Pass a current through your newly-manufactured p–n junction, and the electrons flow from the n-type material into the p-type, whereupon they promptly fall into the holes. As they plummet, they give off a tiny flash of light. </p>
<p>The colour of that light is determined by the semiconductor you’ve used. Silicon, for example, while great for computer chips, isn’t so brilliant for lighting. Light emitted by a silicon LED would be deep into the infra-red range, and invisible to the human eye. Infra-red LEDs are nonetheless very useful: they’re how your remote control allows you to zap instructions to your TV from your sofa. But even here, silicon isn’t used because for <a href="http://en.wikipedia.org/wiki/Direct_and_indirect_band_gaps">quite subtle reasons</a> it’s a very inefficient infra-red light source.</p>
<h2>Lightbulb moment</h2>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/61049/original/6cpmwt8h-1412688850.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The door to a Nobel.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/gnackgnackgnack/4154323430/sizes/l/in/photolist-7k6ZC3-95dV2b-7253Mg-7293wd-7253Bt-2kyd1-qXvPL-HNr9C-biLDXr-61XwJf-5yZ5oP-5yZ66X-5z4n1y-5z4npq-3TXm9p-kVFGcv-kVEgDU-ou1CN-6kpmGz-jjyy4C-6p5pkB-h1H8pU-2kkFA-61XwNm-kVL2La-2kkFy-cR2Gp-gYCr3H-6GNQQv-4a5R1b-2kgCm-2kqRE-2kkFB-2kkFz-4X8fJU-6HjJrL-6HjJos-ndGkcG-h3njwb-jjBinQ-is4dzp-7SeJW3-ubVAr-biLAVM-jraGQR-fmFMDR-4Knibr-7MYZnV-4kEXxV-4kEXzc-4kEXvx/">Patrick Brosset</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>So, if you want to manufacture an LED which emits a certain colour of light, you just need to find a material which has the right properties to give off the colour of light you’re interested in. In some cases this turns out to be quite simple. Red LEDs were available <a href="http://ledmuseum.candlepower.us/1960.htm">from the early 1960s</a>, using materials based on gallium arsenide. Green LEDs followed shortly thereafter using gallium phosphide. However, blue proved something of a challenge. The first commercially available blue LEDs came onto the market in 1989 and were based on silicon carbide but, much like pure silicon, they were phenomenally inefficient.</p>
<p>This is where our Nobel laureates step in. A better choice for producing blue light is gallium nitride (as you’ve probably noticed, gallium something-ide is where it’s at when it comes to making light from electricity). Unfortunately, it’s far trickier to coax bright light from this than the other gallium compounds. </p>
<p>First, it proved very hard to grow high-quality crystals of gallium nitride. Typically, it’s easiest to grow a crystal on a surface which has a similar crystal structure, but gallium nitride’s complex atomic layout makes that somewhat challenging. Then, making the LEDs more efficient requires a complex layering of even more materials, deviating somewhat from the idealised p–n junction LED we just met. Varying widths of the layers in this quantum sandwich can even alter the exact colour of light emitted (theoretically these “blue” LEDs could be tweaked to emit green, yellow or even orange light).</p>
<h2>From blue to white</h2>
<p>In spite of their complex manufacture, blue LEDs are now ubiquitous. For example, they can be found inside Blu-ray players. Blue light has a short wavelength, which allows the pits on a Blu-ray disc to be smaller and closer together than on a DVD, <a href="http://www.scientificamerican.com/article/whats-a-dvd-and-how-does/">which is read with red light</a>. This means that we can pack over five times as much data onto a disk the same size as a DVD.</p>
<p>Their biggest impact, however, is surely in giving us the ability to produce white LEDs. White light is actually a mixture of all the colours of the rainbow, as you can see if you split it up with a prism, or indeed if you catch a <a href="https://www.youtube.com/watch?v=ZowYVDQDDZ4">multicoloured reflection</a> in the surface of a Blu-ray disc, DVD or CD. However, the human eye has <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.html">just three types of colour receptor</a> inside it: red, green and blue.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/61054/original/29v4dfkt-1412690647.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Nobel Prize in your hand.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/highwaysagency/11235762823/sizes/l/in/photolist-i7SdQF-3wcTbc-nUszt2-mu88Ju-6TrRGS-9bnWFi-oq2r8z-nCh79p-bySXDx-8g4HF1-cdKWQA-kJ1f7r-maPTkS-cJawN-4TK6eD-8apr6p-2U28F-5z5baU-nUKPxV-8g1rH4-6bSThp-awfPTp-UFe2C-3wjpXk-4inwq2-3wep8T-6NKeLD-9p1wou-HctH2-7x6fxX-7gLtAT-agFyEa-8g4HYL-4cLKvG-maP7Nz-KomJ4-5NwjMu-UE9kX-4HCbFp-5vF2oF-HcuR4-4irAWj-6NQY8A-DNH41-aJBm4v-aPBv9X-hH4To6-o8P2RT-8asAUG-fKj2e-HcsXy/">Highways Agency</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We can therefore make something which looks like white light using only these three colours. Combining red and green LEDs with blue ones allows us to create highly efficient white lighting, providing around 20 times as much light as an equivalent incandescent bulb. White LEDs are slowly making their way onto ceilings of homes, shops and factories around the world, but their real ubiquity today is as the back-light for computer and phone screens. Unlock your phone or turn on a recent flat-screen monitor, and red, green and blue LEDs shining through a layer of liquid crystal allows you to browse the web, watch movies, and even read this article.</p>
<p>As well as being a technological marvel, Akasaki, Amano and Nakamura’s Nobel Prize is a testament to tenacity in experimental science. As much as deft theoretical insight, the development of blue LEDs required hours of trial and error in the lab, performing the same procedures under subtly different conditions, trying to maximise the efficiency and cost-effectiveness of this finicky process.</p>
<p>The result is a technology which is all around us in the developed world, and making headway into the developing world too. These laureates’ bright idea could well be the light source of the 21st century and, when the movie version comes out, we can even watch their story on Blu-ray on an LED-backlit TV.</p><img src="https://counter.theconversation.com/content/32456/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Steele does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
You’ve probably got the fruits of this year’s Nobel laureates’ handiwork in your pocket. In fact, if you’re reading this on your phone or a relatively recent flat-screen monitor, you’re more than likely…
Andrew Steele, Post-doctoral research fellow, London Research Institute
Licensed as Creative Commons – attribution, no derivatives.