A new device generates energy from shadows
By leveraging the difference between lit and shadowed areas, a new energy source perfect for wearables is invented.
- Mobile devices used both indoors and out may benefit from a new energy collection system that thrives on mixed and changing lighting conditions.
- Inexpensive new collection cells are said to be twice as efficient as commercial solar cells.
- The system's "shadow effect" would also maker it useful as a sensor for tracking traffic.
For all of its promise, solar energy depends on the capture of light, and the more the better. For residents of sunny climes, that's great, with rooftop collection panels, and solar farms built by utilities in wide open, sunny spaces that can provide power to the rest of us. Now, though, a team of scientists at the National University of Singapore (NUS) has announced success at deriving energy from…shadows.
We've got plenty of them everywhere. "Shadows are omnipresent, and we often take them for granted," says research team leader Tan Swee Ching, who notes how shadows are usually anathema for energy collection. "In conventional photovoltaic or optoelectronic applications where a steady source of light is used to power devices, the presence of shadows is undesirable, since it degrades the performance of devices." His team has come up with something quite different, and Tan claims of their shadow-effect energy generator (SEG) that, "This novel concept of harvesting energy in the presence of shadows is unprecedented."
The research is published in the journal Energy & Environmental Science.
How it works
Image source: Royal Society of Chemistry/NUS
The energy produced by the SEG is generated from the differential between shadowed and lit areas. "In this work," says Tan. "We capitalized on the illumination contrast caused by shadows as an indirect source of power. The contrast in illumination induces a voltage difference between the shadow and illuminated sections, resulting in an electric current."
SEG cells are less expensive to produce than solar cells. Each SEG cell is a thin film of gold on a silicon wafer, and an entire system is a set of four of these cells arrayed on a flexible, transparent plastic film. Experiments suggest the system, in use, is twice as efficient as commercial solar cells.
An SEG cell's shadow effect works best when it is half in light and half in shadow, "as this gives enough area for charge generation and collection respectively," says co-team leader Andrew Wee. When the SEG is entirely in shadow or in light, it doesn't produce a charge.
Gold in them that shadows
To be sure, the amount of energy that NUS researchers have thus far extracted is small, but it's enough to power a digital watch. The researchers envision the SEG system harvesting ambient light to power smart phones and AR glasses that are used both outdoors and indoors. While such devices can run on solar batteries, solar is only replenished outdoors, and the SEG could "scavenge energy from both illumination and shadows associated with low light intensities to maximize the efficiency of energy harvesting," says Tan. It seems clear that we're on the cusp of the era of wearables — AR visionwear, smart fabrics, smart watches, and so on — and so Tan considers the arrival of the SEG "exciting and timely."
The researchers also note an additional application for which the SEG seems a natural: It can function as a self-powered sensor for monitoring moving objects. The shadow caused by a passing object would trigger the SEG sensor, which can then record the event.
Next up for the team is investigating constructing cells using other, less costly materials than gold to make them even less expensive to produce.
Famous physicists like Richard Feynman think 137 holds the answers to the Universe.
- The fine structure constant has mystified scientists since the 1800s.
- The number 1/137 might hold the clues to the Grand Unified Theory.
- Relativity, electromagnetism and quantum mechanics are unified by the number.
Younger Americans support expanding the Supreme Court and serious political reforms, says new poll.
- Americans under 40 largely favor major political reforms, finds a new survey.
- The poll revealed that most would want to expand the Supreme Court, impose terms limits, and make it easier to vote.
- Millennials are more liberal and reform-centered than Generation Z.
A 2020 study published in the journal of Psychological Science explores the idea that fake news can actually help you remember real facts better.
- In 2019, researchers at Stanford Engineering analyzed the spread of fake news as if it were a strain of Ebola. They adapted a model for understanding diseases that can infect a person more than once to better understand how fake news spreads and gains traction.
- A new study published in 2020 explores the idea that fake news can actually help you remember real facts better.
- "These findings demonstrate one situation in which misinformation reminders can diminish the negative effects of fake-news exposure in the short term," researchers on the project explained.
Previous studies on misinformation have already paved the way to a better understanding<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU1NzQ4NC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNjE2Mjg1Nn0.hs_xHktN1KXUDVoWpHIVBI2sMJy6aRK6tvBVFkqmYjk/img.jpg?width=1245&coordinates=0%2C800%2C0%2C823&height=700" id="fc135" class="rm-shortcode" data-rm-shortcode-id="246bb1920c0f40ccb15e123914de1ab1" data-rm-shortcode-name="rebelmouse-image" alt="fake news concept of misinformation and fake news in the media" />
How does misinformation spread?
Credit: Visual Generation on Shutterstock<p><strong>What is the "continued-influence" effect?</strong></p><p>A challenge in using corrections effectively is that repeating the misinformation can have negative consequences. Research on this effect (referred to as "continued-influence") has shown that information presented as factual that is later deemed false can still contaminate memory and reasoning. The persistence of the continued-influence effect has led researchers to generally recommend avoiding repeating misinformation. </p><p>"Repetition increases familiarity and believability of misinformation," <a href="https://engineering.stanford.edu/magazine/article/how-fake-news-spreads-real-virus" target="_blank" rel="noopener noreferrer">the study explains</a>.</p><p><strong>What is the "familiarity-backfire" effect?</strong></p><p>Studies of this effect have shown that increasing misinformation familiarity through extra exposure to it leads to misattributions of fluency when the context of said information cannot be recalled. <a href="https://journals.sagepub.com/doi/10.1177/0956797620952797#" target="_blank" rel="noopener noreferrer">A 2017 study</a> examined this effect in myth correction. Subjects rated beliefs in facts and myths of unclear veracity. Then, the facts were affirmed and myths corrected and subjects again made belief ratings. The results suggested a role for familiarity but the myth beliefs remained below pre-manipulation levels. </p>