While the cost of solar power has dropped significantly from the early 2000s, there is still plenty of room for the technology to become cheaper, making it even more attractive as a substitute for fossil fuels. Currently, the cost of the land to build solar installations on and the labor required are the most expensive parts of a solar project. The panels themselves only account for about 20 percent of the cost, but if the solar panels had a much greater energy output, there could be fewer of them generating the same amount of energy, meaning less land required and fewer labor hours. Researchers at the University of California Riverside think they've developed a technology that achieves just that and could lead to much less expensive solar power in the future. The scientists have developed a coating for solar panels that allows them to use the infrared portion of the light spectrum that usually passes right through solar cells without being converted into electricity, essentially wasted energy. They say the new material effectively reshapes the solar spectrum so that it better matches the photovoltaic materials in the solar cells. The infrared portion is then absorbed and used, boosting the conversion efficiency by at least 30 percent. The coating includes cadmium selenide or lead selenide semiconductor nanocrystals combined with organic molecules. The resulting material does what they call "upconverting" photons so that they are readily absorbed by the solar cells. “The key to this research is the hybrid composite material – combining inorganic semiconductor nanoparticles with organic compounds. Organic compounds cannot absorb in the infrared but are good at combining two lower energy photons to a higher energy photon. By using a hybrid material, the inorganic component absorbs two photons and passes their energy on to the organic component for combination. The organic compounds then produce one high-energy photon. Put simply, the inorganics in the composite material take light in; the organics get light out,” said Christopher Bardeen, a professor of chemistry at the university and one of the lead researchers. Besides making solar panels better, this material could also be used to improve things like biological imaging, data storage and organic light-emitting diodes.
News Article | December 18, 2015
Earlier this week on Twitter, I came across quite the sonic phenomena . If you take an mp3 file, convert it to MIDI, then convert it back to mp3, it sounds totally nuts. Just give a couple of these songs a quick listen so you know what you’re dealing with: Weird, right? Andy Baio, a technologist who is an old school blogger and journalist, former CTO of Kickstarter, and founder of the XOXO Festival remixed a couple of songs in this style (after discovering the Carey one on Tumblr) and wrote about it on his blog, calling the version of "All I Want for Christmas Is You" a "terrible and amazing thing to listen to." "The resulting version sounds like Mariah as a player piano—none of the original recording is preserved, only a series of hyperactive notes matching the frequencies of the original song," Baio wrote. "Incredibly, you can still make out the lyrics and music, though likely only if you're familiar with the original song." Baio is right. If you spend your days wandering the mall or listening to Christmas radio, you probably recognize Mariah's impressive vocal intro, though it sounds like she's screaming them from somewhere underwater through an alien voice recorder or something. If you haven't heard the song before, it probably sounds like a stampede of children are jumping on an FAO Schwartz floor xylophone. Before I get into why this isn't merely a "cool thing" but potentially a useful discovery for the field of psychoacoustics , let's discuss what's happening here, technologically speaking. MIDI stands for Musical Instrument Digital Interface—it's a file type with a complex and important history, but I mostly just remember it as the file format that countless bros in college used to make bad songs in Garage Band. It serves more or less as a file format that allows instruments to talk to each other and to talk to a computer—play a ‘C’ note on a MIDI keyboard, and the computer will transcribe it so that you can then play it back as a different computerized instrument altogether (these are called “fonts”). "MIDI is a description of the music—there's nothing in MIDI that says 'play this note in this way,' it says 'here's the note to play—it's a C-note, and play it using this type of instrument,'" Baio told me. "It's recording the fact you hit these notes at this specific time, but it's not recording the sound wave performance of those notes." For this reason, MIDI files are really small and were popular in the early days of the web as a way of putting music on websites. In this case, the MIDI converter is essentially flattening all of the instruments and vocals into one sound track and is recording the sound frequencies of these notes and spitting them out. Baio then used a free online MIDI to MP3 converter to turn them back into an MP3 file, played by a grand piano "font." Basically a piano is playing Carey's vocal notes, the backing vocals, the shimmering drums, the bass, the guitar, the Christmas bells, and everything else in that song, very very quickly. An artist did this with an actual piano back in 2009, and the idea can be visualized in this YouTube video: So, that's how it works. But why does it sound like the vocals are actually there? To be clear, they’re not: There is no vocal or verbal information there whatsoever, you’re merely perceiving notes being hit by a digital piano to be not only a human voice, but a recognizable one with actual words. It is, as the video above suggests, an “auditory illusion.” "If you run a song that you don't know and you try to make out the words, you can't. Your brain is filling in the gaps. If you know the words, the lyrics and the song, you can hear the points very very clearly—the piano is enunciating these words," Baio said. "I think it's your brain filling in the blanks with what you're familiar with." That makes sense, but it's not quite that simple. I emailed James Dias, a researcher at the University of California Riverside's Audiovisual Speech and Audition Laboratory, to learn what's actually going on here. It seems as though Baio may have stumbled onto what could perhaps be a (slightly) new area to focus on for speech researchers. "This is really cool! I've not run into this specific case before. However, the phenomenon seems similar to other acoustic transformations used in speech research," Dias wrote. Dias said that a field of research called sine-wave speech may help explain what’s happening with Baio’s MIDI phenomenon. Dias pointed to the experiment I embedded just above this paragraph in which a person’s voice was converted into a series of bleeps and bloops—“think R2D2,” Dias said—to determine if any meaning could be pulled from them. When listened to out of context, humans can’t decipher much of anything from the sample in the video. But listening to a human speak the “words” that are being converted before hearing the sine-waves changes the context immediately. "The most impressive improvements in identifying speech from sine-wave signals is observed after presenting people with the untransformed signal first and then asking them to identify the speech within the sine-wave replica of that same signal," he added. "Years of studying sine-wave speech has revealed that people can identify not only the speech spoken, but also characteristics of the speaker, such as gender, age, and even accent." Dias says that MIDI is perhaps doing the same thing here. Your brain is only able to recognize the vocals (and the lyrics) once you know what the vocals and lyrics are. "Knowledge of the songs themselves can improve the experience of actually hearing the singer’s voice,” he wrote. “The best example of the effect was, for me, the video of Smash Mouth’s All Star, where you can often see Steve Harwell mouthing the words along with the audio,” which adds a “visual advantage” to the effect. "I myself have never heard of MIDI transformations as a topic of speech research,” he added.”It looks like you have stumbled upon something that may be related to research investigating the influence of other acoustic transformations on speech perception." And that's how a silly little audio transformation that sounds cool and terrible and otherworldly all at the same time could—and maybe should—become the topic of serious research.
Suggestively called Cryptomaster, the herein studied daddy longlegs genus, represented until recently by a single species, is not only difficult to find in the mountains of southwest Oregon, but had also stayed understudied for several decades since its establishment in 1969. Inspired by much newer records of the previously known species, called after the notorious Hebrew monster Leviathan, an American team of researchers from University of California Riverside and the San Diego State University, led by Dr. James Starrett, undertook a new search for mysterious endemic harvestmen, which was successfully concluded with the discovery of another beast, Cryptomaster behemoth. Their work is available in the open-access journal ZooKeys. The Cryptomaster daddy longlegs belong in the largest and incredibly diverse harvestman suborder, called the Laniatores, which are characterized by having relatively short legs and preference for hiding underneath logs, stones and leaf litter in tropical and temperate forests. Typical for many of these well over four thousand species is that they might inhabit very restricted geographic regions and yet be strikingly genetically diverse. This is why when the authors understood about the recently expanded distributional range of the Leviathan's namesake across different mountain ranges, they did not take long to assume that there could be more species having settled nearby. Curiously, both Cryptomaster daddy longlegs species showed two forms of their species, a smaller and a larger one, but neither form was genetically different enough to suggest the presence of a separate group. The scientists observed the variation in both males and females from across both species and all their known localities. Having its localities further increased as a result of the present study, C. leviathan shows surprisingly small genetic distance between its populations. In contrast, its sibling species is so far known to occupy far more restricted range, yet shows considerably more genetic variations. Bearing the name of the huge notorious Hebrew monster Leviathan, the first member of the harvestman genus has won its name because of its excessive size when compared to its relatives within the family of travunioid daddy longlegs. Following the already established trend, the new species is called Cryptomaster behemoth after another large monster known from the Book of Job. "This research highlights the importance of short-range endemic arachnids for understanding biodiversity and further reveals mountainous southern Oregon as a hotspot for endemic animal species," point out the authors in conclusion. Explore further: Two new iguanid lizard species from the Laja Lagoon, Chile More information: James Starrett et al. A new monster from southwest Oregon forests: Cryptomaster behemoth sp. n. (Opiliones, Laniatores, Travunioidea), ZooKeys (2016). DOI: 10.3897/zookeys.555.6274
News Article | August 29, 2016
Contrary to a prevailing theory, coral larvae could not survive the five-thousand-kilometer trip across the Pacific Ocean to replenish endangered corals in the eastern Pacific, according to new research. Researchers used a supercomputer to simulate billions of coral larvae traveling on ocean currents over a 14.5-year period. The simulations showed that even during extreme environmental events that speed ocean currents, like the 1997-1998 El Niño, coral larvae could not survive long enough to make the trip from coral reefs in the western and central Pacific to help corals in the east recover from environmental damage. "Our study uses computer simulations to allow us to answer questions about coral biology that we can't answer in the field," said Iliana Baums, associate professor of biology at Penn State University and a coauthor of the research paper. "The information we gain can help direct conservation efforts for these vital organisms. Without living corals, beaches would erode at an alarming rate -- there are already areas in the Caribbean that are losing a meter of beach a year due to reef loss. Reefs provide habitats for one of the most diverse ecosystems in the world and they are extremely economically important for fisheries, coastal protection, tourism, the aquarium trade, and as sources for new pharmaceuticals. The reefs in the eastern Pacific that we study are particularly important because they survive in inhospitable conditions, and understanding how they do this could be critical when designing strategies for reef conservation as the climate continues to change." The research, by an international team of scientists from the University of Bristol in the United Kingdom, Penn State University, the Rosenstiel School of Marine and Atmospheric Science in Miami, the University of California Riverside, and the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory, will be published by the journal Nature Communications on August 23, 2016. The study used a state-of-the-art numerical model run on Bristol University's BlueCrystal supercomputer to track the dispersal of simulated coral larvae from 636 reef locations in the Pacific. The supercomputer enabled the researchers to deal with the very large computational demands required to explicitly test, for the first time, a long-standing theory that El Niño events could promote long-distance dispersal of coral larvae across the Pacific Ocean. The researchers used the simulations to identify reefs that either are important sources of larvae to other reefs, or are very isolated from such sources and therefore potentially more vulnerable to disturbances. One such area is the Eastern Tropical Pacific, a large area stretching from Baja California in the north to the coastline of Ecuador and the Galapagos Islands in the south. Coral reefs in this region have been around for thousands of years despite living in particularly hostile environments for reef formation with limited suitable coastline, cool temperatures, and frequent disturbances. Eastern Tropical Pacific reefs are sparsely distributed and are also very isolated, both within the region itself and from the more diverse reefs of the central and western Pacific. "We simulated the dispersal of over five billion model larvae from 636 reefs throughout the central and eastern Pacific from 1997 to 2011," said Sally Wood, postdoctoral research associate in coral reef ecosystem modeling in the School of Earth Sciences at the University of Bristol and a coauthor of the paper. "This time period crucially covered a range of oceanographic conditions -- ocean currents are highly variable over time -- including the extreme El Niño of 1997-1998. Contrary to the theory that eastward dispersal may happen during El Niño events, we found no such dispersal." As is happening worldwide at the moment during the current El Niño event, the large El Niño in 1997-1998 wiped out a lot of the corals in the eastern Pacific. Usually corals recover from events like this through a combination of proliferation of survivors and colonization by larvae that are brought in sporadically by the currents from nearby unaffected reefs. However, the new research shows that coral reefs in the far eastern Pacific Ocean, separated from the nearest reefs by over 5,000 km of open ocean, could be on their own when it comes to recovery from mass mortality events such as happened in 1998. Biologists have been interested in this region since Darwin, who regarded the deep ocean that separates the eastern and western Pacific as an impassable barrier. Several of the same species can be found on both sides of the barrier, suggesting that the barrier has at some point been breached, but it is not clear when or how frequently this has occurred, or in what direction. Genetics is commonly used to detect connections between populations by measuring the level of genetic relatedness, similar to a paternity test. Recent genetic data for corals indicate that eastern and western populations of some species have been isolated for at least the previous few generations -- possibly thousands of years in long-lived corals. "We compared these genetic data to the larvae dispersal data that we simulated," said Baums. "The two data sets lined up pretty well, suggesting that our simulations are doing a good job of capturing what is actually happening in nature." "Coral larvae are tiny and can survive for a maximum of about 120 days," said Baums. "The larvae travel mainly by ocean currents to establish new colonies, but because of their small size it is currently impossible to track them across the vast distances of the Pacific Ocean to know if healthy populations of corals in the western Pacific could help to rejuvenate decimated populations of corals in the eastern Pacific. For the first time, our computer simulations combined with genetic data allowed us to test whether the larvae could survive this journey."
An international team from University of California Riverside and the University of Augsburg in Germany has taken a new approach to unraveling the properties of novel two-dimensional semiconductors, materials with unique properties that could offer improved integration of optical communication with standard silicon-based devices. As part of the groundswell of research into new materials for electronic and optoelectronic applications, the work helps improve our knowledge of monolayer films. The study, which was reported in Nature Communications [Preciado et al. Nat. Commun. (2015) DOI: 10.1038/ncomms9593], involved the development of a single-atomic-layer-thin film of molybdenum disulfide on a substrate of lithium niobate, which is employed in a range of electronic devices that use high-frequency signals, such as cell phones and radar installations. Lithium niobate is the archetypical ferroelectric material and the key substrate for many applications, including surface acoustic wave radio frequencies devices and integrated optics. Although it offers a unique combination of properties, its lack of optical activity and semiconducting transport have up to now hampered its application in optoelectronics. On applying electrical pulses to the lithium niobate, the team produced very high-frequency sound waves – "surface acoustic waves" – that run along the surface of lithium niobate like tremors. These surface waves allowed them to listen to how the illumination of lithium niobate by laser light changes the electric properties of molybdenum disulfide. Cell phones use resonances of these surface waves to filter electric signals in the same way that a glass can resonate when tapped at exactly the right pitch. As a glass fills up with liquid, the tone at which it resonates alters, and this tone can help identify how full the glass is. Similarly, the team could “hear” the lithium niobate sound waves and were able to infer how much current the laser light was allowing to flow in the molybdenum disulfide. In addition, they fabricated transistor structures onto the molybdenum disulfide films that proved the accuracy of the analysis. Their prototypical device presents electrical characteristics that are competitive with molybdenum disulfide devices on silicon, and the surface acoustic waves allowed them to realize a sound-driven battery and an acoustic photodetector, which could lead to new ways to non-invasively investigate the electrical properties of monolayer films. As UC Riverside team leader Ludwig Bartels points out, “The well-established nature of the substrates and the processes to create surface acoustic waves makes the novel technique facile and ready to be applied. In particular, even remote, wireless sensing applications appear to be within reach.”