Month: August 2019

August 31, 2019

Physicists Store Images in Vapor

first_img“During the storage time, there are no light fields in the experimental system,” Shuker explained. “All the information carried by the light (in our case the 3D intensity and phase pattern) is converted to the quantum state of the atoms in the vapor (specifically, the coherence between the sub-levels of the ground state). If it was easy to detect the coherence level of the quantum state of the atoms, we would notice that an effective ‘image’ exists – but this is not easily performed (maybe the easiest way is to convert it back to light – as we do in the restoring stage of the experiment).”Due to the diffusion of the gas atoms, the recovered images looked somewhat blurry and had a decreased signal-to-noise ratio. To improve the image resolution, the researchers developed a technique to minimize image degradation caused by the movement of the atoms. The technique is similar to the phase-shift lithography technique used to reduce optical spreading, where the phases of neighboring image features are flipped so that light between them will interfere destructively. The researchers shifted the phases of image features by 180 degrees, so that atoms of opposite phases that diffused to the areas between lines in the image had amplitudes that cancelled, and no light was emitted that blurred the image lines.Storing images in vapor – or, as the researchers describe, “converting optical information to atomic coherence” – could be useful for various image processing and correlation applications, as well as quantum information processing and even quantum communication. The scientists also predict that it should be possible to store more elaborate images, including temporal images, or movies.“The storage-of-light technique (generally, not only images) might have important applications in future quantum information devices,” Shuker said. “The most ‘straight-forward’ application is a ‘memory device’ for the basic information unit of quantum information – the qubit. “Furthermore, the ability to convert quantum information from one representation (a light pulse) to another (atomic coherence) might prove very useful, since each of them has its unique benefits. Photons are excellent carriers of information, and atomic coherence is a good place to store the information – and maybe even process it, since atoms interact with the environment much better than photons.”More information: Shuker, M.; Firstenberg, O.; Pugatch, R.; Ron, A.; and Davidson, N. “Storing Images in Warm Atomic Vapor.” Physical Review Letters 100, 223601 (2008).Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Explore further The original image (left), the image slowed for 6 microseconds (middle), and the image stored for 2 microseconds (right). The technique to improve image resolution was not used for these images. Credit: M. Shuker, et al. ©2008 APS. NIST’s compact atomic gyroscope displays new twists Books are written on solid pieces of paper for an obvious reason: the atoms in a solid don’t move around much, keeping the words and pictures in place for centuries. Trying to store letters and images in a gas medium, on the other hand, seems a little far-fetched. Atoms in a gas are constantly moving around, which would move the images around with them. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.center_img Citation: Physicists Store Images in Vapor (2008, June 23) retrieved 18 August 2019 from https://phys.org/news/2008-06-physicists-images-vapor.html But physicists from the Technion-Israel Institute of Technology in Haifa, Israel, and the Weizmann Institute of Science in Rehovot, Israel, have recently demonstrated how to store images in a warm atomic vapor. With their method, which is based on electromagnetically induced transparency, the researchers could store complex images for up to 30 microseconds in rubidium vapor. To improve the resolution of the retrieved images, the physicists also developed a method to minimize the effect of the diffusion of the gas atoms on the images’ visibility. Images stored for 30 microseconds. The left table shows actual and predicted images without the technique to improve image resolution. The right table shows actual and predicted images with the technique to improve image resolution, where a phase shift was applied to cancel light emission between the lines. Credit: M. Shuker, et al. ©2008 APS. “The basic concepts of the storage of light have been known for several years now, as well as possible applications,” Moshe Shuker of the Technion-Israel Institute of Technology told PhysOrg.com. “What triggered our work was a paper by Howell’s group in Rochester in which they showed they can slow images and delay them for several nanoseconds. We wondered would it be possible to store images – and for how long? Since we used slowing delays and storage durations in the range of microseconds, we immediately noticed the effect of the diffusion of the atoms.”In their technique, the researchers first stored an image (for example, the number “2”) in a light pulse. When that light pulse hits a gas of atoms, it is strongly absorbed, and excites the atoms. But when a second light beam is aimed at the gas, it drives the atoms to a unique quantum state, and causes the first pulse to pass through the vapor. This phenomenon is called electromagnetically induced transparency.As previous experiments have shown, when the second light beam is shut off while the first pulse is inside the vapor, the first pulse can be completely stopped (and be temporarily stored inside the vapor). Then, by starting up the second beam again, the first pulse can be recovered. Here, the physicists used this method to capture, store, and restore complex 3D light fields. The scientists slowed images on a light pulse to a group velocity of 8,000 meters per second, a velocity that allowed the images to be stored in atomic vapor for several microseconds. They directed two light beams to a 5-cm-long vapor cell containing 52°C rubidium gas and a neon gas for buffering. Once half of the first light pulse (containing the image) had exited the vapor cell, the researchers turned off the second beam, so that the remaining half of the image was stored in the vapor. As the researchers explained, during storage, the image was encoded in the quantum state of the ensemble of atoms. After 30 microseconds, the researchers turned the second pulse back on, and the image was then recovered as it left the vapor cell.last_img read more

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Remove software for smartphone can zap photo items w video

first_img Explore further Citation: Remove software for smartphone can zap photo items (w/ video) (2012, February 15) retrieved 18 August 2019 from https://phys.org/news/2012-02-software-smartphone-zap-photo-items.html Scalado, an imaging technology company, is taking advantage of a booming user trend of depending on a single smart device for communication and picture taking functions; “mobile imaging” is an industry slice of the mobile device pie. Scalado last year laid claim to control of a third of the total market for mobile imaging. The company’s various imaging technologies are embedded in millions of mobile devices, according to the company.Last year, Scalado released Rewind, where a “perfect” group shot can be achieved, perfect in the sense that it satisfies the user. Out of a photo burst, the picture-taker can choose which faces or items they like best and merge them into one optimal image. The application, which is processor intensive, was showcased and at the time GigaOM explained how it works: After the picture is taken, the software uses facial recognition to zero in on each member; tapping a face in the picture creates a circular control around the person’s image. A turn of the circle scrolls through images of the face; the best one can be selected and chosen and “stitched” into the final image. Company co-founder Fadi Abbas has said that the company is set to redefine the way memories are edited, searched, and shared at any time on any screen. According to the press release, Remove is the first of other innovations planned for this year. Removal is in prototype but according to reports a fuller version will be showcased at the 2012 Mobile World Conference in Barcelona later this month. The strategy won’t be to make Remove something you can download off an Internet-based app store. Rather, the company plans to go the route of licensing the technology to OEMs. Smartphone makers such as Samsung or HTC, for example, could make Remove a feature for their devices. (PhysOrg.com) — A Swedish company focused on mobile-device imaging technology, Scalado, plans to show object-removal software for the smartphone at this month’s Mobile World Congress in Barcelona. The software lets you remove anything in a photo that you’re taking, with just a screen tap. The only requirements are that the object has to be moving — unwanted pedestrians as you try to capture something on the city streets, for example — for the application to capture and delete. Also, the camera needs to stay still and focused on the subject while you touch each moving item chosen for removal. Remove goes to work by capturing several images in a row, analyzing them to identify which objects are moving and their position in each frame. The user gets to delete what is not wanted and to keep what is wanted for a “clean” final shot. More information: www.scalado.com/display/en/Home Augmented reality in an iPhone app This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2011 PhysOrg.comlast_img read more

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Nanosuits help small creatures survive a vacuum

first_img © 2013 Phys.org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Journal information: Proceedings of the National Academy of Sciences (A–D) A living Drosophila larva was exposed to high vacuum with electron-beam irradiation for 60 min. (F and G) Before SEM observation, a different larva (light micrograph in F) was placed in the observation chamber without electron-beam irradiation for 60 min. (H and I) The specimen collapsed completely when subsequently observed by SEM. Each small white square in C and H is shown magnified in D and I, respectively. (E and J) TEM images are shown of vertical sections through the surface of each animal. The layer between the arrowheads in E indicates the limits of the newly formed outer membrane, not present in J. An outer layer covering the animal represents ECSs in B and G. Credit: (c) 2013 PNAS, doi: 10.1073/pnas.1221341110 More information: A thin polymer membrane, nano-suit, enhancing survival across the continuum between air and high vacuum, PNAS, Published online before print April 15, 2013. doi: 10.1073/pnas.1221341110 AbstractMost multicellular organisms can only survive under atmospheric pressure. The reduced pressure of a high vacuum usually leads to rapid dehydration and death. Here we show that a simple surface modification can render multicellular organisms strongly tolerant to high vacuum. Animals that collapsed under high vacuum continued to move following exposure of their natural extracellular surface layer (or that of an artificial coat-like polysorbitan monolaurate) to an electron beam or plasma ionization (i.e., conditions known to enhance polymer formation). Transmission electron microscopic observations revealed the existence of a thin polymerized extra layer on the surface of the animal. The layer acts as a flexible “nano-suit” barrier to the passage of gases and liquids and thus protects the organism. Furthermore, the biocompatible molecule, the component of the nano-suit, was fabricated into a “biomimetic” free-standing membrane. This concept will allow biology-related fields especially to use these membranes for several applications. Exposure to a high vacuum causes living things to become dehydrated, collapse and die. This poses a problem for scientists who want to study fine structures on small organisms, because they must use SEMs to view these structures. They can only observe dead creatures, so do not get a true picture of how these structures appear on living ones.Hariyama and his team tested how long different kinds of organisms would live in an SEM. As expected, almost all of the living things they studied died quickly. However, to their surprise, fruit fly larvae moved around for a full hour while in the SEM.When the researchers placed fruit fly larvae in a high vacuum SEM observation chamber, but waited an hour before exposing the larvae to electron beams, the larvae all died, indicating that electrons somehow aided the other group’s survival.The researchers found that treatment with electron radiation causes a gooey extracellular substance (ECS), which normally covers fruit fly larvae, to polymerize, forming a 50-100 nanometer thick surface layer. They called this layer, between 1,000 and 2,000 times thinner than a human hair, a “nanosuit.” This nanosuit, while flexible enough to allow the larvae to move, acts as a protective barrier against the vacuum, preventing severe dehydration and enabling the larvae to survive.Hariyama and his team found that they could cause nanosuits to form on fruit fly larvae, as well as on other insects with ECS coatings, by exposing them to ionized plasma particles as well as electrons.They were able to create protective nanosuits for mosquitoes, which do not have natural coatings, by immersing them in Tween 20, a non-toxic chemical found in detergents, and then exposing them to plasma radiation. The researchers point out that plasma and energetic electrons, which exist throughout the universe, could help coated organisms form their own protective nanosuits and survive the vacuum of space.center_img Explore further Citation: Nanosuits help small creatures survive a vacuum (2013, April 16) retrieved 18 August 2019 from https://phys.org/news/2013-04-nanosuits-small-creatures-survive-vacuum.html (Phys.org) —Scientists use scanning electron microscopes (SEMs) to study tiny structures in small organisms. SEMs can only work in a high vacuum, and exposure to such a vacuum normally causes living things to die very quickly. Therefore, until now, scientists have been unable to study living specimens using SEMs. Takahiko Hariyama of the Hamamatsu University School of Medicine in Japan and his colleagues report that they were able to create “nanosuits” for small organisms by bombarding these organisms with electron beams or plasma radiation. In their paper, published in the Proceedings of the National Academy of Sciences, Hariyama’s team reports that these nanosuits provide protection against a high vacuum, allowing the organisms to stay alive in SEMs while scientists analyze them. Ticks found able to survive being subjected to electron microscopylast_img read more

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Study shows rising ocean acidification likely to cause shrimp to taste bad

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Researchers determine optimum cooking times for shrimp and salmon © 2014 Phys.org Explore further Shrimp, as most everyone knows, is wildly popular the world over—but that popularity may be in jeopardy in the future if findings by the team with this new research prove true. Prior research has suggested that the oceans are growing more acidic as they absorb more carbon dioxide from the atmosphere. That increase, the team suggests, along with an increase in temperatures is likely to cause stress to shrimp, which it now appears, will likely cause them to be less pleasurable to the human palate.It is no secret that animals living under stressful conditions wind up suffering degradations in taste—slaughterhouses, for example, attempt to surprise cows, pigs, chickens, etc., with a sudden isolated swift death so that they (and the other livestock) will not stress about their fate beforehand. Now it appears that creatures living in the sea may surprise us in the future with how they taste if they are forced to live under increasingly stressful conditions.The researchers raised shrimp for three weeks in water with a pH level of 7.5 (the level predicted for the oceans by 2100) rather than the normal 8—the water temperature was slightly higher than normal as well to reflect a gradual warming of the oceans by the end of this century. Other shrimp were raised under current normal conditions. All of the shrimp were cooked by professional chefs and fed to volunteer shrimp lovers who rated the shrimp on how well they tasted.The researchers found that the shrimp raised under normal current conditions were 3.4 times as likely to be deemed the tastiest among all the shrimp, while those raised in acidic/warm water were found to be 2.6 times as likely to be described as the worst tasting. The researchers also found that the fish raised in the more acidic/warmer water were 1.6 times as likely to die during the three week test. Thus, unless shrimp learn to adapt to the new conditions so they will not feel stressed, they might just find their numbers increasing as people find them less tasty. Citation: Study shows rising ocean acidification likely to cause shrimp to taste bad (2014, December 23) retrieved 18 August 2019 from https://phys.org/news/2014-12-ocean-acidification-shrimp-bad.html (Phys.org)—A study conducted by a small team of researchers with members from the U.K., Sweden and Canada has revealed that in the future as the oceans become more acidic, it appears likely that the taste of shrimp will become less appealing. In their paper published in the Journal of Shellfish Research, the team describes how they raised test shrimp in higher than normal acidic water and then held taste tests with volunteers. More information: First Evidence of Altered Sensory Quality in a Shellfish Exposed to Decreased pH Relevant to Ocean Acidification, Journal of Shellfish Research 33(3):857-861. 2014 dx.doi.org/10.2983/035.033.0320 ABSTRACTUnderstanding how seafood will be influenced by coming environmental changes such as ocean acidification is a research priority. One major gap in knowledge relates to the fact that many experiments are not considering relevant end points related directly to production (e.g., size, survival) and product quality (e.g., sensory quality) that can have important repercussions for consumers and the seafood market. The aim of this experiment was to compare the survival and sensory quality of the adult northern shrimp (Pandalus borealis) exposed for 3 wk to a temperature at the extreme of its thermal tolerance (11°C) and 2 pH treatments: pH 8.0 (the current average pH at the sampling site) and pH 7.5 (which is out of the current natural variability and relevant to near-future ocean acidification). Results show that decreased pH increased mortality significantly, by 63%. Sensory quality was assessed through semiqualitative scoring by a panel of 30 local connoisseurs. They were asked to rate 4 shrimp (2 from each pH treatment) for 3 parameters: appearance, texture and taste. Decreased pH reduced the score significantly for appearance and taste, but not texture. As a consequence, shrimp maintained in pH8.0 had a 3.4 times increased probability to be scored as the best shrimp on the plate, whereas shrimp from the pH 7.5 treatment had a 2.6 times more chance to be scored as the least desirable shrimp on the plate. These results help to prove the concept that ocean acidification can modulate sensory quality of the northern shrimp P. borealis. More research is now needed to evaluate impacts on other seafood species, socioeconomic consequences, and potential options. A deep sea shrimp out in open water. Credit: National Oceanic and Atmospheric Administrationlast_img read more

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Unusual polyketide metabolites found to give potato rotting bacteria ability to live

first_img(Phys.org)—A team of researchers affiliated with several institutions in Germany has discovered the means by which the common bacteria Clostridium puniceum, which causes pink slime rot in potatoes, is able to survive in an oxygen-rich environment. In their paper published in the journal Science, the team describes the experiments they conducted that led to their discovery and what it might mean for fighting potato rotting in the future. Citation: Unusual polyketide metabolites found to give potato rotting bacteria ability to live in an oxygen-rich environment (2015, November 6) retrieved 18 August 2019 from https://phys.org/news/2015-11-unusual-polyketide-metabolites-potato-bacteria.html Explore further Potatoes are one of the four main food types grown in the world today, which means they make up a substantial portion of the human diet. But growing them has proven to be challenging because they are prone to bacterial infections, which currently result in approximately 65 billion kilograms of lost potatoes every year. Unlike the famous potato blight that caused such misery in Ireland back in the 19th century, most modern infections are bacterial, rather than fungal. In this new effort, the researchers looked at one of the more problematic bacteria, C.puniceum, to see if they could learn how it is able to survive where potatoes are stored, because it is normally anaerobic.Their experiments started with injecting the bacteria into potatoes in their lab and then watching as things developed. Once the bacteria was fully engaged, they studied it under a microscope and discovered that it excreted two unusual polyketide metabolites— clostrubins, type A and type B. To determine if the molecules had something to do with giving the bacteria an ability to live in an oxygen rich environment, the team studied its genes and identified which were responsible for causing the clostrubins to be excreted and then genetically altered some of them so that they were no longer able to do so. Those bacteria, the researchers found, were no longer able to live where oxygen was present, suggesting that the expression of the clostrubins played an essential role in allowing them to live where potatoes are stored.But that wasn’t all—the researchers also found that the clostrubins also served as an anti-bacterial agent against competing bacteria, such as those that cause ring and soft rot and other potato diseases. Thus more study might lead to new types of antibacterial agents for use in warding off potato infections. © 2015 Phys.org More information: G. Shabuer et al. Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory, Science (2015). DOI: 10.1126/science.aac9990AbstractAround 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment.center_img Journal information: Science Researchers find the genome of the cultivated sweet potato has bacterial DNA Source: Wikipedia This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Study shows foraging gene works nearly the same in humans and fruit

first_img Prior research has shown that forms of a gene called PRKG1, known to have an impact on foraging, are present in a wide variety of animals, including both humans and fruit flies (both of whom have a known history of foraging for food). In humans, the form of the gene is a nucleotide polymorphism genotype called rs13499. Prior research has also shown that one variant of the gene in fruit flies nudges them to be “sitters” and another “rovers.” When entering an area with fruit, sitters are likely to first tour the perimeter of the area, then move inward. Rovers, on the other hand, jump right in, going after the first fruit they see. The researchers in this new effort wondered if the same gene in humans might have a similar effect, so they developed experiments to find out.College volunteers used a touchscreen tablet to find as many berries as possible hidden among fruit plants in a virtual scene. They could navigate around the virtual environment and click on fruit to pick it. Each of the volunteers also gave a tissue sample for DNA testing.The researchers found that some volunteers took a perimeter-first approach, while others dove right in. In comparing their genes, the researchers found the same variant responsible for instigating sitter behavior in fruit flies also did so in human sitters and likewise for the rovers. The researchers also noted that the search paths taken by the human volunteers and the sitter and rover fruit flies were nearly identical.The researchers claim their experiments show that distinct search patterns connected to goal pursuit in humans can be associated with PRKG1 variants. Drosophila sp fly. Credit: Muhammad Mahdi Karim / Wikipedia. GNU Free Documentation License, Version 1.2 © 2019 Science X Network Citation: Study shows foraging gene works nearly the same in humans and fruit flies (2019, February 20) retrieved 18 August 2019 from https://phys.org/news/2019-02-foraging-gene-humans-fruit-flies.html An epigenetic key to unlock behavior change Journal information: Proceedings of the National Academy of Sciencescenter_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further More information: Andriy A. Struk et al. Self-regulation and the foraging gene (PRKG1) in humans, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1809924116 A team of researchers from Canada, the U.K. and the U.S. has found that a gene known to influence foraging in fruit flies has a similar effect on humans. In their paper published in Proceedings of the National Academy of Sciences, the group describes experiments they carried out with college student volunteers and what they found.last_img read more

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Nanoscale Lamb wavedriven motors in nonliquid environments

first_img LEFT: A stepping rotary motor. (A) Schematic showing that a specific number (n) of light pulses are emitted at a 1-kHz repetition rate when the light source senses a positive edge on every trigger input. The 1-Hz electric trigger signal is generated by a waveform generator. (B) Step angle of the motor increasing linearly with the light pulse number (n) for one of the trigger inputs. The motor rotates about 0.1° for every single light pulse. (C) Stepping rotation of the motor when the light pulse numbers (n) are 500 and 200. RIGHT: One example application, demonstrating a micromirror for laser scanning. (A) Schematic representation of a rotary plate used as a micromirror to deflect the light beam. The reflected beam rotates 2θ when the plate rotates θ. The distance between the plate and the far field white screen is L (6.4 cm). The relationship between the position of the laser spot on the white screen (y) and the rotation angle of the reflected light (2θ) is y = L × tan(2θ). (B) Sequencing optical images of the laser spot (the center of which is marked with red circles) on the screen in the far field. (C) Experimentally measured and theoretically expected position of the laser spot on the white screen. The rotational speed of the plate, actuated by light pulses at a repetition rate of 5 kHz in the experiment, is 0.95 rpm (0.1 rad/s). The preconceived relationship between y and t is y = L × tan(2ωt + θ0) = 6.4tan(0.2t + θ0). θ0 is the initial angle. Credit: Science Advances, doi: 10.1126/sciadv.aau8271 Light can induce mechanical rotation remotely, instantly and precisely. Light induced micro/nanoscale rotation can generate extensive applications in mechanical actuation, to manipulate biomolecules and deliver cargo. In liquid environments, scientists have demonstrated light-driven rotation by transferring linear and angular momentum to micro-sized objects. In nonliquid environments, dominant forces of adhesion prevent the motion of micro-sized objects. Since adhesion can seriously impede the operation of rotary motors actuated by momentum transfer, liquid is typically used to minimize unwanted impacts. In the present work, Lu et al. deviated from this long-held view to report on a light-actuated motor, where the forces of adhesion in air counterintuitively allowed rotation. The process was assisted by the Lamb wave (a thermo-elastic expansion generated by plasmonic heating of the absorbed pulse light) and the geometrical configuration of the plate-fiber. In the work, Lu et al. demonstrated a light-actuated micromirror with a scanning resolution of 0.001 degrees. They controlled the rotation velocity and stop resolution of the motor (gold plate on a microfiber) by varying the repetition rate and pulse wave in the setup. The scientists showed the motor crawl step-wise, with sub nanometer locomotion resolution in the experiment. The work offers unprecedented application potential to integrate in micro-opto-electromechanical systems, outer-space all-optical precision mechanics and controls, and as laser scanning for miniature lidar systems (light-based navigation/mapping systems). © 2019 Science X Network To construct the microfibers, Lu et al. used a flame-heated drawing technique and synthesized the gold plate containing a single crystal with an atomic smooth surface, in the shape of hexagons or triangles as previously reported. They then experimentally suspended the uniformly fine-drawn optical microfiber in air, or vacuum and placed the gold plate on it using a probe. They used scanning electron microscopy (SEM) imaging to view the plate-microfiber system. During instantaneous on/off movements of a continuous wave (CW) laser, the scientists observed subtly weak azimuthal movement of the gold plate. The movement was due to the expansion/contraction of the gold plate, the accidental effect triggered the pulsed delivery of a supercontinuum light into the microfiber. Using this process, the scientists showed how the gold plate revolved around the microfiber as the light pulses were guided into the setup where Van der Waals forces were responsible for the tight adherence of the plate to the microfiber. Incidentally, since the separation between the gold plate and microfiber was so small, the Van der Waals forces became dominant. When the scientists conducted the same experiment in liquid, the forces of adhesion became smaller, in this instance the gold plate moved away from the microfiber and stopped rotating, showing the necessity of adhesion forces for motion in this setup. For additional insight into the mechanism, the scientists conducted finite element coupled thermal and elastic simulations. The results confirmed the experimental outcomes and indicated that the propagation direction of the Lamb wave generated in the plate-microfiber system was independent of the direction of light propagation within the microfiber. Lu et al. propose using the nanoscale motor thus developed in a variety of fields including micro-opto-electromechanical systems in outer space, during energy conversion and in vacuum high-precision mechanics. The rotating plate can also be used as a scanning micromirror to deflect a laser beam as shown in the study, for laser scanning in miniature lidar systems to map the world in 3D or as laser display systems and optical modulating/switching for integrated microsystems. The new discovery of light-actuated locomotion can open a new era of optical driving and manipulation at the sub-nanometer resolution of locomotion for controlled motion. The work will allow physicists and materials scientists to explore the new landscape of optical nanomanipulation in environments that require a new paradigm, beyond the existing liquid-based function. Citation: Nanoscale Lamb wave-driven motors in nonliquid environments (2019, March 19) retrieved 18 August 2019 from https://phys.org/news/2019-03-nanoscale-lamb-wave-driven-motors-nonliquid.html The motor also worked in vacuum, where the gas pressure was about nine orders of magnitude lower than in air. The rotation speed was linearly proportional to the repetition rate of light pulses and increased linearly, to show that a single light pulse could actuate the motor to rotate at an extremely fine angle. Lu et al. used a waveform generator to produce a signal that could trigger the light source to emit a specific number of pulses and calculated the angle between the microfiber and plate using the projection method. Each light pulse actuated the motor to rotate at a constant angle. The scientists confirmed this result with further experiments.The scientists ruled out optical forces as the driving force during rotation, since the use of CW laser sources of different wavelengths did not cause any rotation to occur; only a pulsed light source with a single wavelength (1064 nm) could drive the motor to rotate. Indicating that pulses played an essential role to generate motion. Previous studies had similarly shown that pulsed light could excite coherent phonons to induce lattice expansion and contraction, to propagate light-induced acoustic waves for many practical applications in optofluidics and bioimaging. Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College of Optical Science and Engineering, Department of Electrical and Computer Engineering, School of Engineering and the Institute of Advanced Technology in China and Singapore, developed a vacuum system and achieved rotary locomotion where a micrometer-sized, metal hexagonal plate approximately 30 nm in thickness revolved around a microfiber. They powered the motor (plate-fiber) using a pulsed light, which was guided on the fiber by an optically excited Lamb wave. The procedure enabled a plate-fiber geometry motor favorable for optomechanical applications in practice; results of the study are now published on Science Advances. The present results were specifically observed since Lu et al. generated a pulsed light-induced Lamb wave on the thin gold plate placed on the surface of the microfiber, to move the plate across the microfiber surface. They illuminated the phenomenon by explaining that first, when a pulsed laser is focused on a line on the surface of a light-absorbing film, surface acoustic waves known as Rayleigh waves can be generated. The pulsed light is then absorbed by the film to locally heat the surface, causing thermo-elastic expansion to generate surface acoustic waves that can clean adhesive particles on the surface. The Rayleigh wave and Lamb wave have similar patterns of motion, therefore, for instance, when the thickness of a film/plate is smaller than the wavelength of a Rayleigh wave, the Rayleigh wave will gradually transition to a Lamb wave. Explore further Researchers report new light-activated micro pump Journal information: Science Advances Light-actuated rotation of a motor in air. A motor that is driven by a pulsed supercontinuum light with different repetition rates in air (movie sped up 10x). Credit: Science Advances, doi: 10.1126/sciadv.aau8271 Schematic illustration of an experimental setup with a hexagonal gold plate on a microfiber and a pulsed supercontinuum light delivered into the microfiber, with light power measured at the output (pulse duration 2.6 ns, repetition rate 5 kHz, wavelength 450 to 2400 nm). Credit: Science Advances, doi: 10.1126/sciadv.aau8271 , Proceedings of the Royal Society A More information: 1. Nanoscale Lamb wave–driven motors in nonliquid environments advances.sciencemag.org/content/5/3/eaau8271 Jinsheng Lu et al. 08 March 2019, Science Advances.2. On Waves Propagated along the Plane Surface of an Elastic Solid londmathsoc.onlinelibrary.wile … .1112/plms/s1-17.1.4 Lord Rayleigh, November 1885, Proceedings of the London Mathematical Society.3. On waves in an elastic plate royalsocietypublishing.org/doi … .1098/rspa.1917.0008 Horace Lamb, March 1917, Proceedings of the Royal Society A.4. Light-driven nanoscale plasmonic motors www.ncbi.nlm.nih.gov/pubmed/20601945?dopt=Abstract Liu M. et al., 2010 Nature Nanotechnology. , Nature Nanotechnology Practical applications of the plate-fiber geometry motor demonstrates a light-actuated rotary micromirror in the lab. Credit: Science Advances, doi: 10.1126/sciadv.aau8271 LEFT: Light-actuated rotation of a motor in air and vacuum. (A) Schematic of experimental configuration showing that a pulsed supercontinuum light (pulse duration, 2.6 ns; repetition rate, 5 kHz; wavelength, 450 to 2400 nm) is delivered into a microfiber and light power is measured by a power meter at the output end. The microfiber is suspended in air or vacuum, and the gold plate is placed on it and then rotates around it due to the actuation of the pulsed light. (B) False-color scanning electron micrograph of a gold plate (side length, 11 μm; thickness, 30 nm) below a microfiber with a radius of 880 nm. Note that the plate-microfiber system is placed on a silicon substrate after rotation experiments. (C) Sequencing optical microscopy images of the anticlockwise revolving gold plate around the microfiber in air (sample A, 5 kHz). The measured average light power is 0.6 mW. (D) Sequencing SEM images of a clockwise revolving gold plate (long side length, 10.5 μm; short side length, 3.7 μm; thickness, 30 nm) around a microfiber (radius, 2 μm) in vacuum. The measured average light power is 1.5 mW. Arrows in (C) and (D) represent the direction of light propagation. Gray circles and yellow lines below (C) and (D) denote the microfiber and plate, respectively. Red curve arrows indicate the rotation direction of the plate. RIGHT: Relationship between rotation speed and repetition rate. (A) Effective width (Weff) of the plate obtained from every frame of experimental videos (sample A, 1 kHz). (B) Fourier transformation of the effective width to obtain its variation frequency (i.e., rotation speed of the plate). (C) Light-actuated rotation speed of the motor increases linearly with repetition rate of light pulses, and different samples give similar results. The power for every light pulse remains the same when the repetition rate is changed. Credit: Science Advances, doi: 10.1126/sciadv.aau8271 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Written on the dancing body

first_imgNatya Tarangini is all set with their next edition of Parampara series titled Bhavayami– an aesthetic representation of dance, music and literature that kick starts on 3 September in the Capital. The three-day event will showcase two dance and music concerts every evening. Yamini Reddy will be opening the stage on 3 September with her Kuchipudi dance along with her group from Hyderabad followed by Ambi and Bindu Subramanium in a fusion band titled SubraMania. Also Read – ‘Playing Jojo was emotionally exhausting’Born to the legendary Kuchipudi exponents, Raja and Radha Reddy in 1982, Yamini has got dance in inheritance from her parents. She has been awarded the YuvaRatna Award, Youth Vocational Excellence award by the District Rotaract Organisation, the Young Achievers award by FLO Delhi and Hyderabad, the Devadasi National Award and the Bismillah Khan Yuva Puraskar by Sangeet Natak Akademi. She has also participated in national and international festivals. SubraMania is the band featuring Bindu and Ambi Subramaniam. Their performances include fusion, jazz, pop-rock and Indian music. They perform their own original material in addition well-known standards and classics. Also Read – Leslie doing new comedy special with NetflixThe second day (4 September) will feature Kathak duet by Vidha and Abhimanyu Lal (son of Kathak maestro Pt. Durga Lal) followed by Sarod recital by Ayaan Ali Khan (younger son of Ustad Amjad Ali Khan).Vidha has received Sri Krishana Gana Sabha endowment award 2010, Chennai and made a Guinness world record for taking most numbers of Kathak spins (103) in one minute in 2011. Abhimanyu Lal has been awarded Shri Krishana Gana Sabha endowment award and Nritya Jayantika award. He has performed at the highest level in India and abroad in many prestigious dance festivals like Sydney dance festival at Seymour centre-Australia 2014, 64th Indian republic day celebration in Dubai 2013, LondonOlympics 2012 and many more. Ayaan Ali Khan represents the seventh generation of a musical lineage known as the SeniaBangash School. The younger son and disciple of the Sarod titan Amjad Ali Khan, Ayaan stepped into the world of music and the Sarod, at a very early age. Ayaan has been performing concerts in India and world-wide, since he gave his solo debut at the age of eight. The last day (5 September) will feature Bhavana Reddy (daughter and disciple of Padmabhuashans Dr.s Raja Radha Reddy and Kaushalya Reddy) performing traditional Kuchipudi dance followed by Indo-Western rock music concert along with her group from Los Angeles. She is an acclaimed Kuchipudi dancer and singer-songwriter. She released her self-produced debut EP Tangled In Emotions. Her music is a blend of Indian concept of melodies with western harmonies held together by a string of poetry.last_img read more

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A day of students and the scribe

first_imgThe occasion was graced by the presence of Hindi fiction author, Prem Pal Sharma and Manas Ranjan Mahapatra, editor at the National Book Trust of India, who was instrumental in the publication of the translations of Cheng’s book. Cheng was accompanied R Sangitha and Kusha Grover, students, in an enrapturing rendition of Water in all three languages. Following was an exciting and energetic interaction ever witnessed by the young learners of Ahlcon. Also Read – ‘Playing Jojo was emotionally exhausting’The author spoke to the students about his passion and motivation for writing. Cheng shared, ‘I started reading as soon as I could hold a book and began my writing career by writing on the walls at the age of three’. He is influenced by the utopian world of Narnia created by C.S. Lewis, his favourite author.When asked his opinion about the moral lessons he wishes to teach the children, Cheng said ‘I doesn’t start writing with a didactic in mind. Instead, I simply write what occurs to me at the time.’ In conversation with the Principal Ashok Pandey, Cheng lamented one possible reason for the children, shunning books and reading is that their parents don’t read themselves. The bookWater conveys the message to value this resource and endeavour to save it.last_img read more

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French sporting fraternity honours victims of the Paris terror attacks

first_imgA minute’s silence will be observed ahead of all French football, rugby and basketball matches this weekend as the world of sport moved to honour the 12 victims of the Charlie Hebdo attack on Thursday. The tribute was observed during the Ligue 1 match between Lille and Evian yesterday night followed by an emotional rendition of La Marseillaise, the French national anthem, as players of both teams wore black armbands. France’s professional football league said that a minute’s silence will also be observed at all Ligue 1 and Ligue 2 matches this weekend. “Following the terrible attack yesterday at Charlie Hebdo, the French Football Federation has decided to observe a minute’s silence on all pitches of the Hexagon (France) this weekend, during national, regional and district competitions. The entire family of French football joins the general spirit of solidarity and affirms its support for the families of the victims,” the FFF said in a statement.last_img read more

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