Paper highlights need for correctly measuring solar cell efficiency

first_img Sharp develops solar cell with world’s highest conversion efficiency ( — As the pace of solar cell research continues to accelerate, the question for every new design is “what’s its efficiency?” Since measuring how efficiently a solar cell converts sunlight into electricity involves several factors, making a correct measurement can be challenging. Henry Snaith, a physicist at the University of Oxford who designs solar cells, estimates that compounding small mistakes in measuring efficiency can result in overestimations of up to five times that of the actual value. More information: Henry Snaith. “How should you measure your excitonic solar cells?” Energy Environ. Sci., 2012, Accepted Manuscript. DOI: 10.1039/C2EE03429Hvia: Chemistry World To address this problem, Snaith has written a guide for researchers on correctly measuring solar cell efficiency for different types of solar cells. As he explains in the paper published in Energy & Environmental Science, a uniform method for measuring efficiency is essential for enabling valid comparisons. “There’s an ongoing stream of papers in which it’s not entirely clear exactly how the measurements have been made,” Snaith said in an article in Chemistry World. “If, for example, someone claims their hybrid solar cell has an efficiency of 4% when it’s really more like 1%, that makes it problematic for someone else to write an exciting paper when they’ve genuinely improved something to 1.5%.”One of the most common potential sources of error that Snaith identifies involves how to mask the cells, which determines the size of the test area. Other problems can occur due to light source calibration and how the cell is positioned during testing. Snaith outlines standards for all these steps, and explains how small deviations can inadvertently cause errors.Snaith emphasized that the purpose of the guide is not to find fault, but to address the challenges involved in the rapidly growing field of solar cell technology that is attracting researchers from diverse backgrounds. He hopes that the guide will encourage new ideas and increase the rate of new breakthroughs.“The research field of photovoltaics is booming due to the recognized imperative to realize long-term solutions to clean and inexpensive power generation,” he writes. “…If these standard protocols are adhered to across the field, then a much better comparison between literature values of efficiency can be made and more rapid and well-directed technological advancements will occur.” © 2011 Citation: Paper highlights need for correctly measuring solar cell efficiency (2012, February 27) retrieved 18 August 2019 from A new guide outlines the correct procedures for measuring solar cell efficiency. Image credit: Wikimedia Commons CC BY 3.0 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

Tardigrade brought back to life after being frozen for thirty years

first_imgAcutuncus antarcticus, an individual representing the SB-3 strain, showing Chlorella sp. inside its stomach. Scale bar, 100 μm. Credit: Cryobiology (2015). DOI: 10.1016/j.cryobiol.2015.12.003 Explore further A huge chunk of a tardigrade’s genome comes from foreign DNA 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. (—A trio of researchers with Japan’s National Institute of Polar Research has found that a microscopic creature known as a tardigrade, was able to “come back to life” after being frozen for over thirty years. In their paper published in the journal Cryobiology, the team reports on where the tardigrade was found, how it was frozen, the technique they used to thaw the creature and how its offspring fared. More information: Megumu Tsujimoto et al, Recovery and reproduction of an Antarctic tardigrade retrieved from a moss sample frozen for over 30 years, Cryobiology (2015). DOI: 10.1016/j.cryobiol.2015.12.003AbstractLong-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers. In the available studies of long-term survival of micrometazoans, instances of survival have been the primary observation, and recovery conditions of animals or subsequent reproduction are generally not reported. We therefore documented recovery conditions and reproduction immediately following revival of tardigrades retrieved from a frozen moss sample collected in Antarctica in 1983 and stored at −20 °C for 30.5 years. We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade, Acutuncus antarcticus, providing the longest records of survival for tardigrades as animals or eggs. One of the two resuscitated individuals and the hatchling successfully reproduced repeatedly after their recovery from long-term cryptobiosis. This considerable extension of the known length of long-term survival of tardigrades recorded in our study is interpreted as being associated with the minimum oxidative damage likely to have resulted from storage under stable frozen conditions. The long recovery times of the revived tardigrades observed is suggestive of the requirement for repair of damage accrued over 30 years of cryptobiosis. Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms. Tardigrades (also known as water bears, because of the shape of their head) are one of the hardiest creatures on Earth, they can be frozen, boiled, put in a vacuum, dried to the point of having almost no moisture left in their body, and still return to living a normal life once put back into a normal environment. They can also apparently survive being frozen for decades, no worse for the wear. The team in Japan reports that two tardigrades were found among a sample of moss collected at Showa Station in Antarctica in November 1983—both were put into a freezer and kept at approximately minus 20 degrees C. Then, in 2014, the team decided it was time to thaw them to see if they could be revived, and if so, how well they fared.Both tardigrades (named SB-1 and SB-2) were placed in a warm environment and allowed to thaw—both showed signs of life on the first day. SB-2 failed to fully revive, but SB-1began to move around in just under a week and was back to its old self by the end of two weeks—it later laid eggs which hatched normal healthy tardigrades. The team reports that the original moss sample also contained a tardigrade egg, which was also frozen under the same conditions as the adult tardigrades, and it was thawed as well. They report that the egg eventually hatched and that the tardigrade from it survived to adulthood and eventually would up laying eggs of its own, which in turn hatched several healthy offspring.This new effort marks a record number of years for revival of a tardigrade after being frozen (the previous record was nine years), but not for any creature—the current record holder is a nematode that survived being frozen for almost 39 years. Such creatures are able to withstand such conditions because they put themselves into a state known as cryptobiosis, which is where all metabolic processes stop. Citation: Tardigrade brought back to life after being frozen for thirty years (2016, January 18) retrieved 18 August 2019 from © 2016 Phys.orglast_img read more

New nanosheet coating could replace nonrecyclable metalized films in food packaging

first_imgHigh aspect ratio LDH nanosheets. a Schematic showing (I) calcination (interlayer water and anions are removed by calcination) and (II) reconstruction process and the preferential growth inhibition in a high dielectric constant solution: thickness growth is much slower than the diameter growth, giving high aspect ratio nanosheets. TEM image (b), AFM image (c) and height profiles (d) of the LDH NS reconstructed in glycine solution. The inset in TEM image represents the diameters measured by TEM. e Mean aspect ratio of the original LDH, LDH NS and control LDH reconstructed in water (Water-LDH). Aspect ratio was calculated by diameter divided by thickness of individual particles from AFM measurements of samples at more than three different spots. Error bar represents the standard deviation from more than 30 measurements. f Estimation of crystallite sizes calculated from Scherrer equation (Eq. (2)) confirming the significant growth inhibition along the c-axis. The red box with dotted line and the blue circle with dotted line represent the estimation of the diameter growth and thickness growth with reaction time. Error bar represents standard error in the curve fitting. g IR spectra: formation of hydrogen bonding evidenced by a red shift of the asymmetric vibration of COO− group of glycine and that part of the group is shifted to orthogonal position (νas⊥(COO−) = 1557 cm−1) during reconstruction in glycine solution. The black lines are assigned to the asymmetric vibration of COO− group and the red line is attributed to the shift to orthogonal position of part of the group. Credit: Nature Communications (2019). DOI: 10.1038/s41467-019-10362-2 The shiny silver coating often used to keep packaged foods fresh is most often seen on the insides of bags of potato chips and candy bars. What many people may not realize is that the familiar silver coating makes such packaging very difficult to recycle because the metal film must be removed from the plastic, which means most of it winds up in a landfill. In this new effort, the researchers have come up with a replacement for the metalized films that are fully and easily recyclable.The new film was made using an inexpensive process that produces thin films made from water and amino acids. More specifically, they were made by first creating a nanosheet of non-toxic synthetic clays. The nanosheet was then stabilized using amino acids. The resultant films are transparent, and most importantly, do not allow gases or water vapor to pass through. In practice, the films would be applied to a plastic, such as those already used in packaging, such as polyethylene terephthalate—the same kind of plastic also used in water bottles. The researchers have already tested the film by exposing it to several gases currently in use in food packing and found it to be approximately 50 percent less permeable. They also put it through physical abuse tests to make sure it could stand up to the processes that packaged foods must endure. They report that it withstood such abuse as well as the metalized films currently in use.The researchers note that because the films are synthetic, their final makeup is in the control of companies that use it as a packing replacement. But they also acknowledge much more testing will need to be done with the films before companies would be willing to switch over to using it instead of the more familiar metalized films. A team of researchers at the University of Oxford, in the U.K., has developed a new type of nanosheet coating for food packaging that could replace the metalized films currently in use. In their paper published in the journal Nature Communications, the group describes their process and hopes that their product might make a whole class of food packing more recyclable. Citation: New nanosheet coating could replace nonrecyclable metalized films in food packaging (2019, June 13) retrieved 18 August 2019 from More information: Jingfang Yu et al. High gas barrier coating using non-toxic nanosheet dispersions for flexible food packaging film, Nature Communications (2019). DOI: 10.1038/s41467-019-10362-2 © 2019 Science X Networkcenter_img Making products more biodegradable with starch Explore further Journal information: Nature Communications 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

KMC joins hands with CESC in bid to check power theft

first_imgKolkata: In a major stride to prevent power theft, the Kolkata Municipal Corporation (KMC) is installing new technology in coordination with the CESC.This technology will be implemented in a planned manner in all the markets under the KMC, where there have been numerous complaints of power pilferage by illegal hooking. The detailed plan on how to go about this venture has already been prepared by the Lighting & Electricity department of the KMC. Also Read – Rain batters Kolkata, cripples normal life”It is impossible to track those people who indulge in power theft through hooking or other means. However, to curb such practice, we are using timers in our lights and at the same time connecting the main switches with Miniature Circuit Breaker (MCB),” said a senior official of the KMC’s lighting department. The timer will ensure that electricity could not be used beyond a specified time, while the NCB technology will result in tripping of power as soon as there is any overload in the line connected with the Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedmain switch. Elaborating on the technology, the official said if MCB is connected with a main switch that can light up 5 lamps with a capacity of 100W each in a specified area, the power will trip if somebody tries to draw power by hooking, “The technology is being integrated in a way that this power tripping can be monitored by us centrally,” the official added. The expenditure for putting the technology in place will vary depending upon the length of wiring and the coverage area. “We will gradually extend this technology to control theft in the lights of the KMC on all the roads across the city. Work has already started,” said Manzar Iqbal, Member Mayor in Council (Lighting & Electricity). The KMC is also working upon replacing all high pressure sodium vapor lamp fittings (HPSV) and Metal Halide Fittings with LED lights to bring down the level of carbon emission and at the same time reduce consumption of electricity.last_img read more

Early life stress may up binge eating in females

first_imgStress during pregnancy may cause female children to exhibit binge-eating-like behaviour in adulthood, a study conducted on mice has showed.Although stressed mothers passed along binge eating-related epigenetic tags on their DNA, the mouse pups’ tendency to binge surfaced only when they too were subjected to stressful situations,the researchers said.”The price we pay later in life – whether it’s psychiatric disorders, metabolic syndromes, or heart-related illnesses – is heavily impacted by the way your brain was programmed early in life,” said Alon Chen, a neurobiologist at the Weizmann Institute in Israel. Also Read – Add new books to your shelf”We have established a model where we can actually show that early life stress increases the likelihood of binge eating in females,” Chen said.For the study, detailed in the journal Cell Metabolism, the researchers genetically engineered a line of mice, where they manipulated the hormone system that controls cortisol – stress hormones – release to increase the anxiety levels of pregnant mothers during their third trimester.The mouse pups’ tendency to binge only surfaced when they were placed in a stressful situation where the researchers restricted their access to food.In addition, measuring the eating habits of stressed mice showed that those born to stressed mothers were more likely to eat large amounts of food during short windows of time. However, putting the young mice on a diet with “balanced” levels of nutrients such as Vitamin B12 and folate, the researchers were able to prevent their binge eatinglast_img read more

ECs monitoring panel to keep check on election material ads

first_imgDarjeeling: Election-related advertisements and campaign posts on social media will be under strict scrutiny by the Election Commission during the forthcoming general elections this time.”A monitoring and certification committee has been constituted at the district level as per the direction of the Election Commission. Any sort of advertisement or campaign advertisements or materials will not be allowed to be printed or broadcast before prior certification from the monitoring and certification committee,” stated Joyoshi Das Gupta, District Magistrate and District Election Officer (DEO.) Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseHowever, there is a time-frame for this. Any candidate or party will have to submit material being published or broadcast three days before. For individuals it will be seven days. The advertisements or campaign materials for print will be checked and certified within 48 hours. For electronic, it will be on the same day. “Nothing will be allowed to be published or broadcast without prior clearance or certification. This is to ensure that the model code of conduct is not violated,” added the DEO. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataCandidates along with the parties fielding their candidates will have to file separate affidavits stating if they have any criminal cases (whether ongoing or convicted) in a prescribed format. The affidavits will be filed thrice (separately by the candidate and the party from the last date of withdrawal of nomination to 48 hours before the closing of polls). A new app has also been launched by the Election Commission. Known as the Citizen’s Vigil App it will be used to keep a strict check. “If any person is found violating the norms, then citizens have to take a video clip and upload it through the app. The complaint will come to the district centre from where a team will scrutinise the matter. The case will be disposed of within an hour. Cases like distribution of liquor, cash to voters can be reported through the app.last_img read more

Soulmate Bringing together maestros and promising artists

first_imgTwenty art maestros are coming up to present a plethora of artwork at a group exhibition titled ‘Soulmate’. Curated by Renu Khera, Director of National Institute of Fine Arts, the show illustrating art as the reflection of the soul, will be held from June 1 – 4 at Visual Arts Gallery, New Delhi.The exhibition puts forth the various facets of Indian mythology, religious thoughts, vintage theme, culture, life and nature. An amalgamation of artworks by the artists of Indian origin from across the world, the exhibition features names like Sujata Bajaj, Niladri Paul Bratin Khan, Arpan Bhowmik, G Subramanian, Swati Pasari Also Read – Add new books to your shelfand Sandeep Chhatraband among others.The event will also bring together promising upcoming artists to showcase their work. “All the 20 different artists have different mediums of work and different thought processes. So to see them together under one roof is truly going to be an unforgettable experience for the spectators”, says Renu Khera, curator of the show.Bratin Khan, one of the artists and the master of traditional and folklore themes, will bring alive the themes of Indian mythology. Fragile, emotive and rich in colour, Bratin’s works use the traditional method of tempera painting, which goes back to the Indian miniatures. Seven to eight coats of transparent color are put on the surface, one after another to get a complete tone. Simple but evocative, Arpan Bhowmik’s art is a study in contrast. Bhowmik’s paintings showcase the vintage theme of a heritage city, Kolkata bringing the city and its humdrum affairs to life with his brushstrokes. Whereas, a painter and a collagist, G. Subramanian uses the medium of collage, and layers it along with acrylic paint and ink washes in brilliant hues to create mixed media works. Also Read – Over 2 hours screen time daily will make your kids impulsiveNiladri Paul’s work bears ample testimony to his talent, integrity and awareness of his surrounding reality. Deriving inspiration from everyday life, he captures vividly the mood and spirit of his subjects. The young and vibrant artist from Kolkata, Swati Pasari, describes her latest collection of sculptures as ‘Celebrating Life’. Through her collection, she has made an attempt to understand her own personality and life around her. “My paintings are a reflection of my thought process. When I paint, I think and feel inner peace and beauty, serenity and calmness. So my paintings manifest these feelings. As I go along with the creations, I build on the idea of what the painting should look like”, says Swati.”They say that you have to be lost in order to be found. Every artist strives for inner peace, and art is only a method of finding inner wholesomeness”, adds Swati.last_img read more

Bad behaviour towards spouse is more impactful

first_imgRefraining from bad behaviour toward a significant other during stressful life events is more important than showing positive gestures, a study has found.Compared with positive behaviour, negative ones tend to trigger more intense and immediate responses, researchers said. How a couple works together during trying times is associated with individual well-being as well as satisfaction with the relationship.”When people face stressful life events, they are especially sensitive to negative behaviour in their relationships, such as when a partner seems to be argumentative, overly emotional, withdrawn or fails to do something that was expected,” said researcher Keith Sanford, a professor at Baylor University in the US. Also Read – Add new books to your shelf”In contrast, they’re less sensitive to positive behaviour,” he said. The study also found that low doses of a behaviour are most important, and over time, more extreme levels have less impact. After negative behaviour reaches a certain saturation point, it appears that stress is only minimally affected by further increases in the dose of relationship problems,” he said.For the study, published in Journal of Family Psychology, researchers surveyed couples experiencing stressful life events to measure their behaviour, relationship satisfaction, personal well-being and quality of life. Also Read – Over 2 hours screen time daily will make your kids impulsiveIn the first study, 325 couples who were married or living with a partner all reported experiences of at least one of six possible stressful events within the past month, including: losing a job, becoming a primary caregiver of an older relative, experiencing a parent’s death, and experiencing bankruptcy, foreclosure or repossession of a house or car. The second study included 154 people who were either married or living with a partner and experiencing a serious medical issue meeting one or more of these criteria: a condition requiring hospitalisation or a trip to the emergency room, a serious chronic condition and a life-threatening condition.All participants reported that they had visited a medical practitioner within the past year for treatment of their conditions.All participants also were asked questions about how rewarding their relationships were, their general well-being and their quality of life. The second study, examining couple’s behaviour showed lower levels of negative behaviour than the first study dealing with other types of stressful issues.last_img read more

Showcasing unity of Gandhis India

first_imgAmid the celebrations of Mahatma Gandhi’s 150th birth anniversary, Khadi and Village Industries Commission decided to mark the occasion with practical display of Gandhian thoughts on village industries.With the co-operation of 150 highly-skilled potters from across the nation, the commission has finally started the project of making a 150-square-meter wall mural made of kulhad at Morbi, Gujrat. The potters have brought clay of their respective regions which have been mixed to produce the Kulhads for the mural. 3,870 kulhads (75 mm diameter and 90 mm height ) out of 5,000 will be produced on electric pottery wheels given by KVIC. Also Read – Add new books to your shelfTalking about the project, Vinai Kumar Saxena, Chairman, KVIC said that it was like starting a yajna (holy ritual) when 150 pandits (common surname of potters in many parts of India) gathered here to introduce the unity of Indian civilization with their individuality. Noted Gandhian philosopher and Mahatma Gandhi’s granddaughter Tara Gandhi Bhattacharjee believes that making the grand mural of Mahatma Gandhi is the fittest tribute to him and his philosophy on Khadi. The philosopher said, “As Bapu always advocated for empowering the village craftsmen and laid stress on adoption of swadeshi products, this grand mural – made directly from the village artisans – will definitely showcase the cultural integrity and unity of Gandhi’s India.” Also Read – Over 2 hours screen time daily will make your kids impulsiveExpressing his happiness on this tributary endeavour of KVIC, the Minister of State for MSME Giriraj Singh stated that it would certainly be a tribute with a difference. “It will really be a proud moment for the nation when KVIC’s grand mural will prominently be displayed in the heart of the national Capital – showcasing the combined ‘sweaty’ efforts of village potters across the nation,” he said. Present at the ceremony, 98-year-veteran Gandhian Gokul Dasji Kala, also hailed KVIC’s novel way of paying tribute to Mahatma Gandhi. It may be noted that the Meenakshi Lekhi, New Delhi Lok Sabha MP along with KVIC Chairman and NDMC Chairman made a vast survey for the selection of prominent site – where the 150 square meter wall mural could be mounted. Later, main building of NDMC in Connaught Place was unanimously decided to be the place for installing the mural. The artwork designed by an Ahmedabad-based designer terracotta and ceramic art studio, Clay Club Innovations, is expected to be unveiled on January 30 – the ‘Shaheed Diwas’ and Martyr day of Mahatma Gandhi. KVIC has also requested the Prime Minister to grace the function as the Chief Guest. So far, KVIC has distributed more than 5,000 Electric Potter Wheels’ sets in the country under its ambitious ‘Kumhaar Sashaktikaran Yojana’ and the distribution of another 7,000 Electric Potter Wheels is in the pipeline.last_img read more

Railway service from New Jalpaiguri to Darjeeling suspended

first_imgDarjeeling: As rains continued in the Hills, there were reports of more landslides in the Darjeeling and Kalimpong districts.The Darjeeling Himalayan Railway service from New Jalpaiguri to Darjeeling has been suspended owing to the tracks being blocked with debris, rocks and trees from a landslide. Darjeeling and Kalimpong Hills have been witnessing incessant rainfall for the past few days triggering landslides. On Tuesday, a landslide on the National Highway 55 in between Tindharia and Ghayabari resulted in the suspension of Darjeeling Himalayan Railway services from NJP to Darjeeling. “We are trying to clear the debris, rocks and trees that have fallen on the tracks. As soon as the lines are clear the NJP-Darjeeling services will resume,” stated a DHR official. The Darjeeling to Kurseong section is however functioning normally. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataThe NH55 between Kurseong and Siliguri was also closed to vehicular traffic owing to this landslide. Earth movers were pressed into service to clear the debris. By evening part of the debris were cleared thereby allowing vehicles to ply. A landslide at the Ghayabari bypass road from Ghayabari caused the road to sink. A part of the road was washed away. In Darjeeling town, there was a landslide in front of Loreto Convent school. Debris and soil from the slide blocked the road to the school. Earth movers were pressed into service to clear the road. The vulnerable hill side was covered with tarpaulin sheets to stop seepage of water. Also Read – Lightning kills 8, injures 16 in stateBlocked drains and Jhoras further aggravated the situation. After a visit to the landslide site, Anit Thapa, Chairman, Gorkhaland Territorial Administration stated: “We have requested the Municipality to give priority to cleaning up the drains and jhoras to ensure smooth flow of water.” He then visited the Ghoom Jorebungalow area. “There are multiple slides in the Ghoom Jorebungalow area. Houses and roads have been damaged. We have called for a report of the damages. The earth moving equipment have been kept on standby. We are on alert and keeping a close tab on the situation. The GTA will also provide tarpaulin sheets in case of shortage,” added Thapa. Meanwhile, in Upper Rongpo Bustee in Kalimpong the house of one Manju Tamang was fully damaged in a landslide. However, there was no report of any human casualty. The Indian Meteorological Department in a weather bulletin has issued orange warning (heavy rainfall to very heavy rainfall) for July 10 to July 12. As per the bulleting Kalimpong received 14 cm of rainfall and Darjeeling 10 cm of rainfall in the past 24 hours.last_img read more