New Unusual Semiconductor is a SwitchHitter

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. New record: 3-D-printed optical-electronic integration Explore further ( — A research group in Germany has discovered a semiconducting material that can switch its semiconducting properties — turning from one type of semiconductor to another — via a simple change in temperature. This intriguing behavior may make the material useful in efforts to create better performing integrated circuits, which form the backbone of almost all electronic devices.center_img Semiconductors are essential to integrated circuits, and any significant advances in semiconductor materials could mean big changes for the future of electronic technologies. For example, this new finding may further developments in data-storage technology. At a more fundamental level, the material could change how semiconductor chips are designed.”This new material may be able to help simplify chip production in the future,” the study’s corresponding researcher, chemist Tom Nilges of the University of Muenster, in Germany, said to “Instead of using two materials to build transistors for integrated circuits, there is now a reasonable chance that this job could be performed by a single material.”The material is a compound containing silver, tellurium, and bromine, abbreviated Ag10Te4Br3. At three distinct temperatures—290 degrees Kelvin (K), 317 K, and 390 K (62, 111, and 242 degrees Fahrenheit, respectively)—the material changes from a p-type semiconductor (excess positively charged “holes,” or electron absences) to an n-type (excess negative carriers), and back to a p-type. These changes are reversible.Silver-based semiconducting compounds tend to have many interesting electrical properties, mainly because they can conduct both electrons and silver ions exceptionally well. This makes them useful in a variety of electronics applications. For example, they are being eyed as good candidates for a certain type of memory device.Another possible application for these materials is in the relatively cheap production of electricity without the simultaneous emission of planet-warming greenhouse gases. Ag10Te4Br3 may be particularly suited to this, as it has interesting thermal properties. For example, over the temperature range 355 K – 410 K, the material displays a strong and broad endothermic response, meaning it absorbs a large amount of heat from its surroundings.In addition, it does not rapidly adjust its temperature in relation to its surroundings — it has a very low “thermal diffusivity” — and displays a huge thermopower drop, meaning the voltage across the material changes rapidly in response to changing temperature. Such a large thermopower change has not before been observed.The ability of Ag10Te4Br3 to switch from p-type to n-type and back again is the result of several complex structural changes it undergoes in response to the changing temperature. In combination, these changes allow the material’s electrical properties to morph so dramatically. Some of the tellurium ions form mobile chains; the silver ions coordinate to those chains. There is also a shift in the concentration of charge carriers—electrons and holes—which is connected with the chain-forming tendency of tellurium.Future research into Ag10Te4Br3 may focus on its potential to allow fine-tuning of its physical properties, beyond the changes caused by temperature alone.Citation: Nilges et al. Nature Materials 8, 101-108 (2009); advance online publication, (doi:10.1038/nmat2358)Copyright 2007 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Citation: New, Unusual Semiconductor is a Switch-Hitter (2009, January 30) retrieved 18 August 2019 from read more

Energy harvesting skin generates power from air conditioners

first_img The researchers, Soobum Lee from the University of Notre Dame in the US and Byeng Youn from Seoul National University in South Korea, have published their study on the EH skin in a recent issue of Smart Materials and Structures and IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. The research was partially supported by the POSCO Genesis Program.“EH skin is a new and innovative design paradigm for vibration and thermal energy harvesting,” Youn told “The EH skin was proposed to overcome the disadvantages of a traditional cantilever-type EH device and enables a power-generating skin structure. The cantilever-type EH devices require a bulky device fixture, resulting in significant energy loss due to imperfect clamping. To the contrary, the EH skin enables a compact and highly efficient EH implementation as a part of a vibrating structure.”The EH skin works by taking advantage of the piezoelectric effect, which is the ability of some materials to produce electricity when subjected to mechanical stress. Previous research has shown that PZT (lead zirconate titanate) has the highest energy conversion efficiency compared to other piezoelectric materials. In the new study, the researchers designed and fabricated a skin made of thin PZT patches, which are directly attached to a vibrating surface using a conductive epoxy. As the researchers explained, attaching thin piezoelectric patches is a well-known method for vibration control. However, the patches have never been used to harvest energy, as far as the researchers know.In their experiments, the researchers used the piezoelectric skin to harvest the vibrations of a condensing unit in an outdoor air conditioner. They optimized the topology and the shape of the piezoelectric skin so that it would convert the condensing unit’s vibrations into electricity as efficiently as possible. The design concept is based on a segment-type design scheme, introduced by the researchers in an earlier study, that segments piezoelectric patches to eliminate the energy cancellation effect. Soobum Lee and Byeng D. Youn. “A design and experimental verification methodology for an energy harvester skin structure.” Smart Mater. Struct. 20 (2011) 057001 (9pp). DOI: 10.1088/0964-1726/20/5/057001Soobum Lee and Byeng D. Youn. “A new piezoelectric energy harvesting design concept: multimodal energy harvesting skin.” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control Vol 58 Issue 3. Pages 419-442, March 2011. DOI: 10.1109/TUFFC.2011.5733266 Explore further Citation: Energy harvesting skin generates power from air conditioners (2011, April 20) retrieved 18 August 2019 from (Left) This cooler condensing unit on the campus of the University of Maryland provides a high vibration level for energy harvesting. (Right) The researchers chose the top plate of the unit as a design space for the EH skin due to its relatively high vibration level. Image credit: Lee and Youn. ©2011 IOP Publishing Ltd. A personal tour of the Australian Synchrotron, and a few of its impacts on Australia 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. ( — Devices that harvest ambient energy from the surrounding environment have become popular since, for some applications, they eliminate the need for batteries that must constantly be replaced. One of the most widely available forms of ambient energy is vibration, which occurs in buildings, machines, bridges, staircases, and the human body, among other places. The most common type of device used to harvest vibration energy is the cantilever, which generates electricity by bending. In a new study, researchers have developed an energy harvesting (EH) device in the form of a flat skin rather than a cantilever, and have shown that it can generate enough power to operate multiple wireless sensor nodes. When testing the skin, the researchers found that it could generate power at an average of 3.7 mW, which is sufficient for operating wireless sensor units. As the researchers explained, self-powered wireless sensors could eliminate the need for battery replacement, leading to significant cost savings.“According to the US Department of Energy, maintenance costs for battery use in wireless sensor applications are estimated at $80-500 per replacement, including labor, which exceeds the sensor’s cost,” Youn said. “At the same time, about half a billion wireless sensor nodes were consumed by 2010, according to ON World, and this consumption will continue to grow substantially over the years. If EH skin is successfully implemented for self-powered wireless sensors, sustainability and maintainability will be significantly improved with a great economic gain.”Some of the applications of wireless sensors include the structural health monitoring of buildings as well as building automation systems, which monitor and control the mechanical and lighting systems in a building.“Building automation is one of the key research areas in the future that can enhance the energy sustainability of buildings by reducing electric energy consumption in lighting by 60%, in climate control by 45%, and in heating by 25%,” Youn said, citing a 2007 LonMark survey carried out by researchers at Technical College Biberach in Germany. “This is possible by monitoring the temperature, humidity, and motion using self-powered wireless sensors. The application of the self-powered sensors to the prognostics and health management area will enable smart health monitoring systems, which are free from battery replacement, to anticipate system failure in advance and make an optimal decision on maintenance. This will reduce maintenance costs significantly in many engineering fields, such as (nuclear) power plants, transportation, buildings, automotives, and defense applications.”In the future, the researchers plan to utilize multiple vibration modes in the EH skin to significantly enhance the power conversion efficiency. They also plan to develop a multifunctional EH skin that can perform energy harvesting, energy storage, noise reduction, and load carrying. Future applications could also include using the EH skin in aircraft and ground vehicles. More information: Copyright 2010 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of last_img read more

Samsung defends Android Galaxy S3 PenTile display

first_img © 2012 Phys.Org Citation: Samsung defends Android Galaxy S3 PenTile display (2012, May 14) retrieved 18 August 2019 from 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. ( — So what’s a hot new Galaxy S3 smartphone doing with a PenTile AMOLED display like this? That is a question that surprised developers and smartphone blog sites earlier this month when Samsung announced in London its new Galaxy S3 with a 4.8-inch 720p resolution display that uses a PenTile subpixel layout. Expectations were that the Galaxy S3 would carry another type of upgraded display The PenTile design had drawn disappointed reviews when it had earlier appeared on the Galaxy Nexus phone. This week, however, a Samsung spokesperson stepped forward to explain why PenTile was still chosen: Samsung wants the S3 phone displays to last longer. Samsung’s Philip Berne, a marketing manager, discussed the PenTile instead of RGB matrix decision. (RGB stands for “red green blue,” referring to the subpixel matrix used in displays. The PenTile pixel system uses sub-pixels in a different formation than do RGB displays.)Berne told MobileBurn that the choice came down to durability and longevity. Samsung, he said, determined that PenTile AMOLED displays have proven to be more reliable than those with RGB layouts. Displays that use AMOLED technology have a tendency to deteriorate over time. Blue subpixels on AMOLED displays degrade the fastest, quicker than the red or green subpixels. With a PenTile layout, the subpixels are arranged RGBG (red, green, blue, green), so they feature more green subpixels and fewer red or blue subpixels than an RGB format.As a result, AMOLED displays with a PenTile layout have a longer lifespan than those with RGB layouts. Those who have panned the PenTile arrangement in the past complained that the screen does not look as crisp as an RGB display and that, with the PenTile display, images may appear fuzzy around the edges. Berne, however, pointed out in MobileBurn that improvements were made. He said that, in comparison with the 4.65-inch 720p Super AMOLED screen on the Google Galaxy Nexus, the Samsung 4.8-inch display on the Galaxy S3 features smaller gaps in its subpixel matrix, to minimize fringing effects in a PenTile layout.Still, it seems that the PenTile decision this week has generated mixed reactions, if not emotions, from smartphone bloggers and developers. “No plus here,“ was one reaction to the news that the panel is featuring a PenTile RBGB pixel arrangement. Another comment was “Nice processor, shame about the PenTile.” Longevity may be a bigger plus, however, for average Samsung consumers than for a more demanding, pixel-sensitive, user base. What’s more, favorable reactions among Samsung Galaxy S3 reviewers were also forthcoming. They said they found no problem created by the display design.“We really could not see any issues with the screen,” wrote Dan Seifert in MobileBurn. Elsewhere, several Android forum contributors said that PenTile effects can only be seen if you are really looking for them. Samsung demonstrates 10.1-inch, 300dpi WQXGA penTile RGBW prototype tablet displaylast_img read more

Study shows city life may cause permanent change in circadian clock for

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. Citation: Study shows city life may cause permanent change in circadian clock for blackbirds (2013, June 5) retrieved 18 August 2019 from ( —An international team of researchers working in Germany has found that blackbirds that live in the city tend to have different circadian rhythm cycles than do blackbirds that live in a nearby forest. In their paper published in Proceedings of the Royal Society B, the researchers describe the results of their field and lab study comparing activity times of the two groups of birds. Explore further © 2013 More information: Clocks for the city: circadian differences between forest and city songbirds, Published 5 June 2013 doi: 10.1098/rspb.2013.0593AbstractTo keep pace with progressing urbanization organisms must cope with extensive habitat change. Anthropogenic light and noise have modified differences between day and night, and may thereby interfere with circadian clocks. Urbanized species, such as birds, are known to advance their activity to early morning and night hours. We hypothesized that such modified activity patterns are reflected by properties of the endogenous circadian clock. Using automatic radio-telemetry, we tested this idea by comparing activity patterns of free-living forest and city European blackbirds (Turdus merula). We then recaptured the same individuals and recorded their activity under constant conditions. City birds started their activity earlier and had faster but less robust circadian oscillation of locomotor activity than forest conspecifics. Circadian period length predicted start of activity in the field, and this relationship was mainly explained by fast-paced and early-rising city birds. Although based on only two populations, our findings point to links between city life, chronotype and circadian phenotype in songbirds, and potentially in other organisms that colonize urban habitats, and highlight that urban environments can significantly modify biologically important rhythms in wild organisms.center_img Researchers and most people who live in cities have known for some time that birds that live in cities tend to become active earlier in the morning than do birds that live in the country—or in this case a forest. In this new effort, the researchers wanted to know if birds that live in the city had permanent changes to their circadian cycle.To find out, they captured six blackbirds that lived in Munich and another six that lived in a forest approximately 25 miles away. Each bird was outfitted with a radio transmitter that allowed the researchers to monitor their activity. Each of the birds was then released back into the environment where it was found. Birds from both groups were monitored for a week then were all recaptured and taken back to a lab. In the lab, all of the birds were put into isolation chambers where ambient light was held fixed and sound was cut off. Inside, the birds were unable to determine the time of day. Their activity was monitored for ten days, after which the birds were released back to where they had been captured.In analyzing the data obtained from their efforts, the researchers found that blackbirds native to the city became active on average 29 minutes before the sun came up in the morning. Forest birds on the other hand, rose with the sun. They also found that the city birds tended to keep busy for approximately 6 minutes longer at the end of the day than their forest dwelling city cousins.In the lab, the isolation was meant to determine if the differences in activity were specifically tied to temporal city life or whether the changes had become permanent. Watching the birds indicated the change was more likely the latter. The city birds demonstrated faster biological clocks—they went through their circadian day on average 50 minutes faster than did the birds from the forest. The researchers also found their behavior rhythms tended to weaken faster as well.The research team acknowledges that their sample size is too small to form definite conclusions, but add that their findings do suggest that city living may impact biological cycles. For that reason, they suggest more research be conducted to discern whether there is a similar difference for people and if so, what impact it might have. Blackbirds in the spotlight: City birds that experience light at night ready to breed earlier than their rural cousins Journal information: Proceedings of the Royal Society B Turdus merula. Credit: Andreas Trepte / Wikipedialast_img read more

Class Connect

first_imgChiranjiv Bharati School, Palam Vihar hosted a British Council Connecting Classrooms Meet onFriday  in its premises. It was a commendable initiative by Archna Luthra, Trustee and the School Principal Sangeeta Saxena. Principals and senior teacher coordinators were invited from Gurgaon to help them add an international dimension to their teaching and learning process helping their students to have a broader international outlook.last_img

Mumbais life line halted commuters go on rampage

first_imgThe trouble started at Diva station in Thane district after rail services were disrupted when pantograph of a local train broke between Thakurli and Dombivali stations on Up slow line, triggering violent protests by passengers.During stone pelting by protestors, a motorman of a Kalyan-CST local got injured which led to a flash strike by motormen. However, the services resumed on the Central and Harbour lines as motormen called off their stir after being assured adequate police protection. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJI“All railway services on the Up and Down lines have been restored completely. Trains are running as usual now. I wish to appeal to the people not to block railway lines when an incident like this takes place. Stopping trains further derails our efforts to restore services in case of a mishap,” Central Railway’s senior PRO Anil Kumar Jain told PTI.Tempers flared up as hundreds of commuters found themselves stranded on Friday morning. Angry protestors squatted on tracks and pelted stones at the railway property. Also Read – Health remains key challenge in India’s development: KovindThey also set on fire at least three vehicles, including a police jeep, a Thane civic official said.In the protests, seven automatic ticket vending machines (ATVMs), three booking counters at Diva railway station, Level Crossing Gate Boom at Diva level crossing, two booking counters and six ATVMs at Dombivali station and 10 EMU rakes were damaged, Jain said.Also the motormen’s union called for suspension of operations, until assured of proper police protection. Railway Minister Suresh Prabhu said firm steps will be taken by authorities to ensure that the problems faced by commuters due to overload of passengers are eased.“For the last many years, the suburban rail services are facing an overload of passengers. The number of people taking trains is only increasing with time, but services have not increased correspondingly, which causes problems. There needs to be a long term solution to this problem, for which I will speak to the Chief Minister and come out with a plan that will ease commuter tensions,” Prabhu told reporters here.last_img read more

Repoll after ballot grab during counting

first_imgJalpaiguri: A repoll has been ordered in two booths of Jalpaiguri’s Rajganj on Sunday after suspected Trinamul activists snatched ballot papers from the counting centre. Officials said it was rare that a repoll had been ordered because of ballots taken away or damaged during counting .The state election commission ordered the repoll on Friday after “information” that 450-odd ballot papers were taken away from the counting centre at Mahendranath High School on Thursday. Later, some of the papers found near a bus stand.The papers related to votes cast on May 14 at booth numbers 189/1 and 189/2. “The commission has decided that on Sunday (May 20), re-poll would be held in two booths, followed by counting on May 21,” said a Jalpaiguri official.A BJP leader said the party had filed a complaint with the poll panel saying the Trinamul group had grabbed the ballots and demanding a repoll.last_img read more

Simple tips to look your best on your DDay

first_imgEvery woman wants to be the centre of attraction and look perfect on special day. Start your skin care from taking at least six to eight hours sleep and eat a lot of super foods as they help in repairing skin cells, says an expert.1. Sleep better: Start your skin care from taking at least six to eight hours sleep everyday for avoiding dark circles or tired eyes. Good proportion of sleep helps to rejuvenate you and balance your hormones. This is the most important thing you need to look like a princess on your special day and also drink 12-15 glasses of water daily to remove toxins from your body. Also Read – Add new books to your shelf2. Eat super foods: A lot of vitamins and antioxidants super foods can help you fight with skin problems. It can also repair your skin cells. You need to eat Vitamin C rich citrus fruits everyday like papaya, kiwi fruit, guava and watermelon. 3. Cleansing your skin: Leave your regular cleansing routine aside for winters. Swap your cleansing milk for rose water, honey, turmeric, sandalwood paste or even saffron face wash to boost your glowing skin naturally.  Also Read – Over 2 hours screen time daily will make your kids impulsive4. Homemade herbal face packs: This is the natural way to get smooth, glowing and supple skin. There are some home-made face packs given below:-5. Tulsi face pack for removing sun tan: Tulsi is known for its antibacterial, anti-fungal properties. Due to its healing properties, tulsi helps in removing sun tan, pigmentation and dark patches. Method: Crush a few tulsi leaves with a little rose water, add two tablespoon of fine sugar, add one tablespoon of lemon juice. Now properly mix it and apply the mixture to your face and neck. Leave it for 10 minutes. While removing the pack gently scrub your face in circular motions especially the sun tan areas. Wash your face using cold water and pat dry.  6. Rose petal face pack for bridal glow: Rose has been the main ingredient in making beauty products from many years. You can prepare a rose petal face pack with some rose petals which gives natural glowing skin. Method: Crush the rose petals with some milk for oily skin and with milk cream for dry skin. Apply the face pack for 20 minutes and wash with lukewarm water. Apply this face pack twice a week.last_img read more