Will Europe Be Powered by the Sahara

first_img First of all, there is the fact that Africa is not exactly connected by land to Europe. The Initiative has a plan for that, though. The Guardian reports that power lines will stretch across the Mediterranean to provide as much as 15% of Europe’s electric power by 2050. Another issue is the fact that there are some, er, less than stable countries involved. Just as energy from oil can be disrupted by conflict and political turmoil in African nations, solar energy in the Sahara could be impacted by problems in the region. And, of course, if Saharan countries agree to allow such farms on their land, it is likely that some of the power will have to go to African cities, and that there will be leases to pay and perhaps royalties. It is likely that some sort of financial arrangement will have to be made, and could affect the project’s profitability.The technology to be used for the solar farms is described by The Guardian:The solar technology involved is known as concentrated solar power (CSP) which uses mirrors to concentrate the sun’s rays on a fluid container. The super-heated liquid then drives turbines to generate electricity. The advantage over solar photovoltaic panels, which convert sunlight directly to electricity, is that if sufficient hot fluid is stored in containers, the generators can run all night.The technology has been around for years, but never used on this scale. There are hopes that, if everything goes well, the first power station of the project could be build by 2015.© 2009 PhysOrg.com Image source: U.S. government via Wikimedia Commons Citation: Will Europe Be Powered by the Sahara (2009, November 4) retrieved 18 August 2019 from https://phys.org/news/2009-11-europe-powered-sahara.html (PhysOrg.com) — Europe has long been interested in developing alternative energy sources. And, one of the more interesting places that some Europeans are looking for solar power is the Sahara. With the vast amounts of sun beating down on the Saharan desert, it seems an ideal place for solar panels. The Desertec Industrial Initiative, a consortium of 12 companies, including Siemens and Deutsche Bank, aims to make Saharan solar power for Europe a reality. But it won’t exactly be easy. Desert power: A solar renaissance Explore further 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

Researchers find way to measure speed of spinning object using lights orbital

first_img © 2013 Phys.org Citation: Researchers find way to measure speed of spinning object using light’s orbital angular momentum (2013, August 2) retrieved 18 August 2019 from https://phys.org/news/2013-08-orbital-angular-momentum.html 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. Most everyone is familiar with the Doppler Effect—it’s what makes the sound of sirens change in pitch as they pass by. Scientists have been using this phenomenon in various ways for years to learn more about the world around us—one application was determining that most observable stars and galaxies are moving away from us, which led to the theory of the expansion of the universe. Scientists have also learned over the years that the Doppler Effect can be applied to rotating objects as well so long as the light source is not aligned with the axis of rotation–light waves reflected off turbo blades, for example, are different depending on if they are moving towards or away from the source.In this new effort, the researchers found a way to measure the spin speed of an object that is not observed at an angle by taking advantage of a characteristic of light known as orbital angular momentum (OAM). This is where electromagnetic energy associated with light flows forward in the direction of propagation while also continuously moving around its own axis. In essence, it’s light moving through space like a corkscrew. The researchers found that light can be imbued with OAM if it is reflected off a rotating object and it was this discovery that led to its use in calculating the spin speed of the object. Specifically, they found they could calculate the spin speed of the object by measuring the OAM in the light that has been reflected back by it.To test their theory, the researchers fired a laser at a spinning plate in their lab then used a light detector to measure the degree of OAM. Because the plate was spinning, it gave off both positive and negative OAM—the degree of difference between the two gave the researchers the speed of rotation of the object.Because the new method allows for determining spin speed head-on and from a distance, it might be used to determine the spin speed of planets, or back here on Earth to fine tune wind turbines. More information: Detection of a Spinning Object Using Light’s Orbital Angular Momentum, Science 2 August 2013: Vol. 341 no. 6145 pp. 537-540 DOI: 10.1126/science.1239936ABSTRACTThe linear Doppler shift is widely used to infer the velocity of approaching objects, but this shift does not detect rotation. By analyzing the orbital angular momentum of the light scattered from a spinning object, we observed a frequency shift proportional to product of the rotation frequency of the object and the orbital angular momentum of the light. This rotational frequency shift was still present when the angular momentum vector was parallel to the observation direction. The multiplicative enhancement of the frequency shift may have applications for the remote detection of rotating bodies in both terrestrial and astronomical settings. Doppler shift. Light scattered from a moving surface can be Doppler-shifted in frequency. This frequency shift can be observed for (A) translation and (B) rotation. Credit: Science 2 August 2013: Vol. 341 no. 6145 pp. 537-540 DOI: 10.1126/science.1239936center_img Journal information: Science Explore further Hall effect at the speed of light: How can you demonstrate relativistic effects with your mobile phone? (Phys.org) —Researchers in Scotland have devised a way to use the Doppler Effect to discern the spin speed of a rotating object where the object is directly facing the light source. In their paper published in the journal Science, the team describes lab experiments they conducted that allowed them to observe a frequency shift proportional to the product of the rotation frequency of an object and the orbital angular momentum of the light.last_img read more

Anticounterfeit polymers work like fingerprints

first_img Anti-counterfeit ‘fingerprints’ made from silver nanowires Credit: Wiley Explore further The best tags use non-deterministic coding, meaning that even if you do the exact same process to make the anti-counterfeit tag as you did for another tag, the two tags will still be different from each other. This makes them desirable for anti-counterfeit. However, there is a cost to using these tags. Non-deterministic tags have a higher degree of randomness but their complexity, or security level, and their decoding strategy are difficult to tailor for various products. This makes many of these types of anti-counterfeit tags inefficient for industrial use.Park and Kwon used the way fingerprints produce unique patterns to design an unclonable and configurable anti-counterfeit tag. Their process involved coating substrates, such as nanoparticles, with silica polymers and subsequently drying the polymer-coated substrate to allow the substrate to shrink, causing to polymer to wrinkle. To test whether their polymer tags were functionally similar to fingerprints, they subjected their polymers to similar techniques used to read fingerprints. In these techniques fingerprint patterns, called minutiae, are studied to identify unique minutia points. Using the fingerprint algorithm, this technique successfully identified minutia points on the silica polymer proving that a known, and ubiquitous technique, can be used to identify security tags. Furthermore, they found that, compared to synthetic human fingerprints, the polymer tags contained more randomized minutia patterns, meaning individual tags were more unique than individual fingerprints.While the wrinkling pattern was not reproducible, even using the same conditions and substrate, Park and Kwon were able to control minutiae density. By varying the reaction time for the coating process or wavelength of UV used for the photopolymerization step they were able to control the wavelength of the minutiae pattern. Wavelength increased proportionally as coating time increased or as the energetic strength of UV light decreased.The greater the complexity of the wrinkle pattern, the higher the security of the tag. Complexity is proportional to density of minutiae per unit length, and density is inversely proportional to wavelength. Therefore, by changing the reaction time or UV strength, the polymer wrinkle wavelength can be tuned for a desired security level. Park and Kwon point out in their paper that “To our knowledge, the presented fingerprinting approach is the first, among nondeterministic codes, to enable tuning of coding capacity or security level.”Lastly, Park and Kwon tested their polymer tag on various objects and under varying conditions. They found that their tag remained intact under high temperatures, sonication, and repetitive swelling and shrinking. Overall, the wrinkle pattern of silica polymers overlaid on a substrate produced a security tag that can be used to ensure the authenticity of various products. The tag has a tunable security level by adjusting the density of minutia in the wrinkle pattern, and the tags are easy to read using the same technology used for fingerprint analysis. (Phys.org)—When it comes to tagging items to prove their authenticity, the goal is to stay ahead of counterfeit technology. The best tags are unique, complex, easy to read, and difficult to reproduce. One naturally-occurring authentication “tag” is fingerprints, which are difficult to replicate, but are easy to read. Wook Park and Sunghoon Kwon from Seoul National University developed a process for making anti-counterfeit tags from wrinkled silica polymers that is based on the way fingerprints are used for identification. Their work is published in Advanced Materials. © 2015 Phys.orgcenter_img Citation: Anti-counterfeit polymers work like fingerprints (2015, February 16) retrieved 18 August 2019 from https://phys.org/news/2015-02-anti-counterfeit-polymers-fingerprints.html Journal information: Advanced Materials 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. More information: “Biomimetic microfingerprints for anti-counterfeiting strategies” Hyang Jong Bea, Sangwook Bea, Cheolheon Park, Sangkwon Han, Junhoi Kim, Lily Nari Kim, Kibeom Kim, Suk-Heung Song, Wook Park, and Sunghoon Kwon, Advanced Materials, 2015 DOI: 10.1002/adma.201405483AbstractAn unclonable, fingerprint-mimicking anti-counterfeiting strategy is presented that encrypts polymeric particles with randomly generated silica film wrinkles. The generated wrinkle codes are as highly unique as human fingerprints and are technically irreproducible. Superior to previous physical unclonable functions, codes are tunable on demand and generable on various geometries. Reliable authentication of real-world products that have these microfingerprints is demonstrated using optical decoding methods.last_img read more

Mystery of peryton reception at Australian observatory solved Its from microwave ovens

first_img Citation: Mystery of peryton reception at Australian observatory solved: It’s from microwave ovens (2015, April 13) retrieved 18 August 2019 from https://phys.org/news/2015-04-mystery-peryton-reception-australian-observatory.html 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. (Phys.org)—A team of researchers working at Australia’s Parkes Observatory has found the source of at least one kind of peryton—a type of radio signal similar to Fast Radio Bursts (FRBs) which are known to come from somewhere else in the galaxy—microwave ovens in a kitchen nearby. The team has written about their investigation and findings in a paper they have uploaded to the arXiv preprint server. © 2015 Phys.org More information: Identifying the source of perytons at the Parkes radio telescope, arXiv:1504.02165 [astro-ph.IM] arxiv.org/abs/1504.02165Abstract”Perytons” are millisecond-duration transients of terrestrial origin, whose frequency-swept emission mimics the dispersion of an astrophysical pulse that has propagated through tenuous cold plasma. In fact, their similarity to FRB 010724 had previously cast a shadow over the interpretation of “fast radio bursts,” which otherwise appear to be of extragalactic origin. Until now, the physical origin of the dispersion-mimicking perytons had remained a mystery. We have identified strong out-of-band emission at 2.3—2.5 GHz associated with several peryton events. Subsequent tests revealed that a peryton can be generated at 1.4 GHz when a microwave oven door is opened prematurely and the telescope is at an appropriate relative angle. Radio emission escaping from microwave ovens during the magnetron shut-down phase neatly explain all of the observed properties of the peryton signals. Now that the peryton source has been identified, we furthermore demonstrate that the microwaves on site could not have caused FRB 010724. This and other distinct observational differences show that FRBs are excellent candidates for genuine extragalactic transients. For several years space scientists have been studying radio signals that emanate from unknown sources—some from somewhere nearby, others from the distant galaxy. The ones that were found to come from close sources have been named perytons—theories about their origin have typically focused on meteorological and/or terrestrial phenomena. No one really knows the source of FRBs, but scientists have suspected it should be possible to track down the source of perytons, since they come from somewhere nearby. To learn more, the research team set up a real-time radio interference monitor at the Parkes site and then waited for the telescope to detect some perytons—they did not have to wait long, this past January, the telescope picked up three peryton signals, but so did the interference monitor. Analysis of data from the device suggested the source was similar to that emitted from microwave ovens. Taking a closer look, the team found they could reproduce the peryton signals received by the telescope by simply opening the door to a microwave in the break room before its timer went off—that tiny moment of time when the magnetron was still pumping out microwaves when the door was open—that allowed for a very short burst of microwave activity that was of course picked up by the telescope.It is still not clear if microwave ovens can be blamed for all instances of peryton reception, but it is a sure bet that any site that hears such signals in the future will first check to see if they are originating around lunch or dinner time. The finding does not suggest FRBs might be generated by a more earthly source, however, since their signals arrive from just one point in space and unlike perytons, they happen at random times.center_img The time-frequency structure of the three January perytons. In the case of events on 2015-01-19 and 2015-01-23 the summed 13-beam data is shown. For 2015-01-22 only beam 01 is plotted as the outer beam data was not recorded to disk. Credit: arXiv:1504.02165 [astro-ph.IM] Journal information: arXiv Explore further Snapshot of cosmic burst of radio waveslast_img read more

Memory shape alloy can be bent 10 million times and still snaps

first_imgIt is not yet clear why the new alloy has such super bending properties, but the researchers suspect that it has to do with its ability to switch from one crystalline form to another, and then of course, back again without suffering from molecular knots, which for most alloys introduce imperfections, which lead to failure. Superelastic iron alloy could be used for heart and brain surgery Transforming Puzzles. Mixtures of the phases possible under the cofactor conditions that have been achieved in a real material by Chluba et al. These structures have zero energy and no stress. The domains in these microstructures are easily rearranged and likely contribute to the exceptional repeatability of the alloy discovered by Chluba et al. Credit: Xian Chen and Richard James © 2015 Phys.org Memory shape alloys got their name by the unique property of being able to be bent and returning to their original shape automatically. Such metals can have their shape altered by subjecting them to physical bending, or by heating them. Up till now, no such alloy was able to snap back after being subjected to bending more than a few thousand times—scientists would like to bump that number up significantly because it would allow for creating devices that are more durable—artificial aortic valves, for example, or as a replacement for liquids in refrigerating devices. But despite a lot of effort, no one had been able to find a way to make that happen.The researchers with the team readily acknowledge that their find was largely luck, they were tinkering with different mixtures, in this case, adding a little bit of cobalt to an already existing alloy made of nickel, copper and titanium. The resulting alloy surprised them during initial testing. Because such an alloy had never been created, neither had a means for testing its durability—they had to come up with two types of testing devices, one to repeatedly bend and allow for release, very quickly and another for heating and cooling. Both types of tests wound up having to run for weeks to reach the ten million mark. More information: Ultralow-fatigue shape memory alloy films Science 29 May 2015: Vol. 348 no. 6238 pp. 1004-1007 DOI: 10.1126/science.1261164 ABSTRACTFunctional shape memory alloys need to operate reversibly and repeatedly. Quantitative measures of reversibility include the relative volume change of the participating phases and compatibility matrices for twinning. But no similar argument is known for repeatability. This is especially crucial for many future applications, such as artificial heart valves or elastocaloric cooling, in which more than 10 million transformation cycles will be required. We report on the discovery of an ultralow-fatigue shape memory alloy film system based on TiNiCu that allows at least 10 million transformation cycles. We found that these films contain Ti2Cu precipitates embedded in the base alloy that serve as sentinels to ensure complete and reproducible transformation in the course of each memory cycle. Journal information: Sciencecenter_img (Phys.org)—A combined team of researchers from the University of Kiel in Germany and the University of Maryland in the U.S. has created a shape memory alloy that is able to be bent and snap back to its original form up to ten million times. In their paper published in the journal Science, the team describes how they came up with the alloy and why they believe it could have a wide variety of uses. Richard James of the University of Minnesota offers a Perspective piece on the work done by the team in the same journal issue. 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. Transforming Puzzles. Mixtures of the phases possible under the cofactor conditions that have been achieved in a real material by Chluba et al. These structures have zero energy and no stress. The domains in these microstructures are easily rearranged and likely contribute to the exceptional repeatability of the alloy discovered by Chluba et al. Credit: Xian Chen and Richard James Explore further Citation: Memory shape alloy can be bent 10 million times and still snaps back (2015, May 29) retrieved 18 August 2019 from https://phys.org/news/2015-05-memory-alloy-bent-million-snaps.htmllast_img read more

Airquality sensors on cars at heart of AclimaGoogle partnership

first_img Explore further Sensors to map air pollution represent an ambitious project involving Google. A number of tech sites are talking about its activities in strapping Aclima sensors to Street View cars. Aclima is in the business of delivering “internet-connected sensor networks.” Video: NASA Researcher discusses the air quality of three cities The initial test was done in Denver, said Lunden, where they were able to instrument three Google Street View vehicles.Constine in TechCrunch said the three cars collected 150 million air quality data points over a month of driving around Denver. “They measured for chemicals that are hazardous to breathe, like nitrogen dioxide, nitric oxide, ozone, carbon monoxide, carbon dioxide, methane, black carbon, particulate matter, and Volatile Organic Compounds (VOCs).”Dave Gershgorn in Popular Science pointed out that “This partnership also comes on the heels of a Google pledge to reduce its own environmental impact. The company joined 12 other industry leaders in signing the American Business Act on Climate Pledge on Monday, pledging to power its Bay Area headquarters on 100 percent renewable energy and reduce water consumption.” © 2015 Tech Xplore Constine said “Independent scientific analysis confirmed that the mobile sensor system worked for collecting street-by-street data and could improve upon the regional network of sensors operated by the Environmental Protection Agency.”Aclima blogged recently: ” To assess if air quality is meeting – or exceeding – public health standards, the EPA relies on an extensive network of stationary equipment, placed in urban areas, that measure carbon monoxide, nitrogen dioxide, sulfur dioxide, particulate matter, hydrocarbons and photochemical oxidants. The monitoring network is designed for air quality regulation, but does not give a detailed picture of a community or urban area such that people can get a real sense of what air pollution is in their immediate surroundings. Aclima’s mobile sensing platform on Street View cars complements EPA’s regional air measurement network by introducing a new body of knowledge about air quality at the street level.”Over the next year they will test to see how viable it is to measure air pollution in more cities. They are planning on expanding to the Bay area, working with community groups and scientists to explore possibilities. This may be a transformative step to advancing air quality monitoring. “Our hope is that one day this information is as accessible as the weather,” said Herzl, where people can access the information on a daily basis and that, together, make smarter decisions that add up to change.On the other hand, there is the question of just how much impact air pollution data unleashed on a city population, down to the streets where they live, might have. How much will residents and leaders be willing to put up with findings, once they learn more about the air quality they breathe? Could such hyper-local data make changes that affect the well-being of residents?Herzl said citizens, scientists, policy-makers and governments around the world need access to this information. She said for the first time there can be a human-scale understanding of what is happening in our environment, and how it is directly affecting us.Herzl offered an example to TechCrunch: “We know that trees absorb pollution, NO2 specifically. If we can know where pollution hotspots are, we can know where to put green spaces.”center_img The finalized prototype of Google self-driving car. Citation: Air-quality sensors on cars at heart of Aclima-Google partnership (2015, July 31) retrieved 18 August 2019 from https://phys.org/news/2015-07-air-quality-sensors-cars-heart-aclima-google.html Their work cuts across three platforms—indoors, outdoors and on vehicles. Referring to the latter, Aclima said, “Vehicles and buses that drive repetitive routes through cities offer perfect platforms for Aclima sensing technology. We outfit vehicles to take community-scale snapshots of pollution and greenhouse gases. In just a few days of driving, an interconnected urban system comes into focus.”Aclima CEO Davida Herzl said many factors inform the quality of life we experience in cities in a video titled “Aclima and Google —How Cities Live and Breathe.”On any city day one can see what Melissa Lunden, director of research, Aclima, sees, as told in the video: “We’ve got buses. We’ve got trucks. We’ve got cars in traffic buildups….all are emitting pollutants that go into the mix of the city.”Aclima is on a fundamental mission toward improving human health through environmental protection. They talk about their plug-and-play sensor modules that are calibrated and adapted to provide detailed, environmental data. The networks measure a broad spectrum of variables, including noise, humidity, carbon monoxide, particulate matter and methane. A fuller list of the variables can be found on the company’s site.Google has been working with Aclima for the past year and a half, said Senior Writer Josh Constine in TechCrunch. 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

Scientists grow highquality graphene from tea tree extract

first_img Journal information: Nano Letters Explore further Is graphene hydrophobic or hydrophilic? (Phys.org)—Graphene has been grown from materials as diverse as plastic, cockroaches, Girl Scout cookies, and dog feces, and can theoretically be grown from any carbon source. However, scientists are still looking for a graphene precursor and growth method that is sustainable, scalable, and economically feasible, since these are all requirements for realizing widespread commercialization of graphene-based devices. Citation: Scientists grow high-quality graphene from tea tree extract (2015, August 21) retrieved 18 August 2019 from https://phys.org/news/2015-08-scientists-high-quality-graphene-tea-tree.html More information: Mohan V. Jacob, et al. “Catalyst-Free Plasma Enhanced Growth of Graphene from Sustainable Sources.” Nano Letters. DOI: 10.1021/acs.nanolett.5b01363center_img In a new study, researchers have grown graphene from the tea tree plant Melaleuca alternifolia, the same plant used to make essential oils in traditional medicine. The researchers demonstrated that they could fabricate large-area, nearly defect-free graphene films from tea tree oil in as little as a few seconds to a few minutes, whereas current growth methods usually take several hours. Unlike current methods, the new method also works at relatively low temperatures, does not require catalysts, and does not rely on methane or other nonrenewable, toxic, or explosive precursors.The scientists, Prof. Mohan V. Jacob at James Cook University in Queensland, Australia, and collaborators from institutions in Australia, Singapore, Japan, and the US, have published a paper on the new technique for growing graphene from tea tree extract in a recent issue of Nano Letters.”This research realizes fabrication of good-quality, few-layer graphene from an environmentally friendly precursor,” Jacob told Phys.org. “Overall, large-area graphene fabrication using a fast, environmentally friendly precursor and process at a relatively low fabrication temperature is the major significance of this work.”For growing graphene, the researchers used a technique called plasma-enhanced chemical vapor deposition. The researchers fed the vaporized tea tree extract into a heated tube, much in the same way as done with methane gas in previous versions. As soon as they switched the plasma on using electrodes, the vapor was almost instantly transformed into graphene film. In every graphene growth method, the final graphene product turns out a little differently. The graphene grown here has a particularly large surface area and long edges, with the scientists estimating the total length of the edges in one square centimeter to be 2.6 km (1.6 miles). Graphene edges have a strong influence on the material’s overall properties, with long edges offering advantages for many applications, including battery electrodes and chemical sensors. Another unique characteristic of the graphene grown here is that it is one of the most hydrophobic graphene samples to date. In general, hydrophobicity increases as 2D graphene attains more layers, becoming more 3D. In support of this relation, microscope images here revealed 3D nanoscale features on the graphene’s surface, which are likely responsible for the strong hydrophobicity. These results suggest that this graphene may have applications for creating various superhydrophobic coatings and surfaces, such as for medical devices and textiles that repel water.The researchers also expect that the graphene films produced from the tea tree extract have potential applications in next-generation nonvolatile memory devices called memristors, which store memory in their levels of electrical resistance. They demonstrated this possibility by sandwiching a semiconductor between graphene and aluminum, creating a device that exhibits memristive properties.The researchers plan to further explore these applications and others in the future.”We will be focusing on optimizing the material properties and implementing the material in various electronics applications,” Jacob said. © 2015 Phys.org (Left) Tea tree leaf. (Right) Microscope images of graphene grown from tea tree oil for (a) 1 second, (b) 1 minute, (c) 2 minutes, and (d) 4 minutes. Credit: Jacob, et al. ©2015 American Chemical Society 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

Astronomers investigate pulsar wind nebula DA 495

first_img Citation: Astronomers investigate pulsar wind nebula DA 495 (2019, May 27) retrieved 18 August 2019 from https://phys.org/news/2019-05-astronomers-pulsar-nebula-da.html More information: A. Coerver, et al. Multiwavelength Investigation of Pulsar Wind Nebula DA 495 with HAWC, VERITAS, and NuSTAR.arXiv:1905.07327v1 [astro-ph.HE]. arxiv.org/abs/1905.07327 Astronomers have carried out a multiwavelength investigation of a pulsar wind nebula (PWN), designated DA 495, to unveil its mysterious physical nature. Results of the study, based on observations using HAWC and VERITAS ground-based observatories as well as NASA’s NuSTAR spacecraft, are presented in a paper published May 17 on arXiv.org. Explore further X-ray observations reveal insights into the nature of the pulsar wind nebula 3C 58 VERITAS image of DA 495. Credit: Coerver et al., 2019. 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. © 2019 Science X Network Pulsar wind nebulae (PWNe) are nebulae powered by the wind of a pulsar. Pulsar wind is composed of charged particles; when it collides with the pulsar’s surroundings, in particular with the slowly expanding supernova ejecta, it develops a PWN.Particles in PWNe lose their energy to radiation and become less energetic with distance from the central pulsar. Multiwavelength studies of these objects, including X-ray observations, especially using spatially-integrated spectra in the X-ray band, have the potential of uncovering important information about particle flow in these nebulae. This could unveil important insights into the nature of PWNe in general.Discovered about half a century ago, DA 495 (G65.7+1.2) was first identified as a point source in the Dominion Astrophysical (DA) survey. Subsequent observations of this source have revealed that it is located some 3,260 light years away from the Earth, and has an extended structure and a non-thermal spectrum. These suggest DA 495 could be a Crab nebula–like supernova remnant.However, more recent observations of DA 495, especially in X-rays and gamma-rays, provided evidence that the object is a PWN in an evolutionary state somewhere between the Crab and Vela-X nebulae. This makes it an excellent target for studies focused on investigating life cycles of PWNe.Moreover, still very little is known about physical properties of DA 495, which encourages scientists to conduct more observations of this mysterious object.Recently, a team of astronomers led by Anna Coerver of Columbia University has reinvestigated DA 495 using new X-ray data from observations performed with Nuclear Spectroscopic Telescope Array (NuSTAR). The study was complemented by analysis of the archival datasets from the High Altitude Water Cherenkov Observatory (HAWC) and Very Energetic Radiation Imaging Telescope Array System (VERITAS).”In this paper we presented new observations from NuSTAR. We combined this new analysis with recent TeV gamma-ray observations and the current radio analysis to create a broadband spectral energy distribution for DA 495,” the astronomers wrote in the paper.The research mainly confirmed previous findings regarding such parameters as photon index, neutral hydrogen absorption, blackbody temperature, and a blackbody radius. In particular, the photon index, at a level of 2.0, is typical for a PWN.However, the astronomers found some evidence that DA 495 may not be a PWN at all. They noted that the radio and TeV emission from this object could be also explained by a thick shell containing relativistic hadrons. Such structure could be accelerated from a supernova shock interacting with some slow supernova ejecta.”This challenges the current interpretation and requires further investigation by future TeV gamma-ray observations,” the paper reads.Therefore, these findings deepen the mystery of the physical nature of DA 495. That is why Coerver’s team proposes more observations of this source, especially in radio to infrared bands and spatially resolved gamma-rays. Such studies have the potential to provide more hints into the physical conditions and radiation mechanisms in this peculiar object.last_img read more

HC bench to hear appeal on Monday

first_imgCalcutta: A Calcutta High Court division bench will on Monday hear separate appeals by the state election commission, the Bengal government and Trinamul against a single bench’s order stalling the panchayat poll process. As a result of the appeals filed on Friday, matters being handled by the single bench of Justice Subrata Talukdar are likely to be referred to the division bench of Justice Biswanath Sommader and Justice Arindam Mukherjee. Also Read – Heavy rain hits traffic, flights Halting the poll process through an interim order on Thursday, Justice Talukdar had asked the election commission to explain on Monday what it had done about Opposition complaints that its nominees were being prevented from filing nominations. On Friday, the commission, the government and Trinamul urged the division bench to hear their appeals on an “urgent basis”. Justice Somadder, the senior judge on the bench, asked the parties to file their appeals right away. “The poll process has already been delayed. The division bench will hear the case again and it will take more time. So there is every possibility of the election dates being deferred,” said a senior lawyer not connected with the case. Inputs from The Telegraphlast_img read more

Package for rainhit farmers before session ends Khadse

first_imgAssuring that a comprehensive financial package for farmers affected by unseasonal rains would be announced before the Budget session ends, Maharashtra government on Wednesday said it was planning a group insurance scheme to help the kin of farmers who committed suicide. Under the group insurance scheme, the kin of the farmers who committed suicide would get Rs two lakh.However, not satisfied with the government’s reply to the marathon debate which took place on Tuesday, the Opposition Congress and NCP staged a walkout as their demand for loan waiver and Rs 25,000 per hectare assistance was not accepted. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIReplying to the debate on the issue in the Assembly, state revenue minister Eknath Khadse, who also heads the agriculture department, said, “I have sought permission of the House on this issue and if needed, the MLA fund and salary for a period of one-year would be freezed.” The minister also said that uncertain climatic changes have caused havoc with the state repeatedly experiencing unseasonal rains and hailstorms in addition to drought.”Panchnamas (evaluation) of some districts are awaited. Even on Tuesday, there was unseasonal rain in some districts. So at the end of the session, we will announce a financial package for the farmers,” he said. Also Read – Health remains key challenge in India’s development: KovindAdmitting that the Centre has not acted on its demand for Central assistance of Rs 6,013 crore, Khadse said the reason was that after the proposal was sent for it, the state repeatedly faced unseasonal rains and hailstorms.”The Centre has asked us for a single proposal, which is not possible as the hardships of farmers do not seem to end because of unpredictable climate. But, (Union Home Minister) Rajnath Singh and (Agriculture Minister) Radha Mohan Singh have assured us that the Centre would give more funds to the state than given by the previous governments,” he said.last_img read more