Printable Flexible CarbonNanotube Transistors

first_img Applications for these flexible electronics include electronic paper, RFID (radio frequency identification) tags to track goods and people, and “smart skins,” which are materials and coatings containing electronic circuitry that can indicate changes in temperature or pressure, such as on aircraft or other objects.Printing circuits onto plastic is not a new achievement. Researchers have created printed circuits at room temperature using various semi-conducting polymers as the carrier transport medium, and many, many research groups across the globe continue to work toward perfecting the process and product.“A problem with these polymers is that they have limited carrier mobility, meaning electrons travel through them fairly slowly. This limits the speed of the devices made from them to only a few kilohertz,” said UMass Lowell Professor Xuejun Lu, the study’s corresponding researcher, to PhysOrg.com.Modern computers, by comparison, have speeds from hundreds of megahertz to more than one gigahertz.As part of the printed-electronics effort, carbon nanotubes have been investigated as a medium for high-speed transistors, with very promising results. But one method of depositing the nanotubes onto the plastic, “growing” them with heat, requires very high temperatures, typically around 900°C, which is a major obstacle for fabricating electronic devices.Additionally, transistors made from single carbon nanotubes or low-density nanotube films, which are produced by depositing a small amount of a nanotube solution onto a substrate, can carry only a small amount of current. High-density films (more than than 1,000 nanotubes per square micrometer, or millionth of a meter) are better, but most are not of sufficient quality, containing carbon “soot” that covers the nanotubes’ sidewalls and hinders carrier flow.To help solve these issues, Brewer Science, Inc. developed an electronic-grade carbon-nanotube solution. The researchers deposited a tiny droplet of the solution onto a plastic transparency film at room temperature using a syringe, a method similar to ink-jet printing.“Our electronic-grade solutions contain ultrapure carbon nanotubes without using any surfactant. Our printed transistor’s carrier mobility is much higher than similar devices developed by other groups, it exhibits a speed of 312 megahertz, and can carry a large current,” said Dr. Xuliang Han, Senior Research Engineer at Brewer Science. This research is described in the November 16, 2007, online edition of Micro & Nano Letters.Citation: Micro & Nano Letters — December 2007 — Volume 2, Issue 4, p. 96-98Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Scientists from the University of Massachusetts Lowell and Brewer Science, Inc. have used carbon nanotubes as the basis for a high-speed thin-film transistors printed onto sheets of flexible plastic. Their method may allow large-area electronic circuits to be printed onto almost any flexible substrate at low cost and in mass quantities. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore furtherlast_img read more

Scientists Make TemperatureRegulating Coffee Mug

first_imgThe PCM absorbs the warmth of the mug’s content, stores it and brings it down to the optimal temperature. Then the PCM helps maintain the content’s temperature at this optimal level by slowly releasing the stored heat back into the mug’s contents. Image credit: Fraunhofer IBP. (PhysOrg.com) — A well-insulated mug may keep your coffee somewhat warm, but now scientists have designed a high-tech mug that can keep drinks hot or cold at the perfect temperature for up to half an hour. Citation: Scientists Make Temperature-Regulating Coffee Mug (2009, August 25) retrieved 18 August 2019 from https://phys.org/news/2009-08-scientists-temperature-regulating-coffee.html Intel, STMicroelectronics Deliver Industry’s First Phase Change Memory Prototypes Researchers Klaus Sedlbauer and Herbert Sinnesbichler from the Fraunhofer Institute for Building Physics have created the temperature-regulating mug using phase change material (PCM). PCM is capable of storing and releasing large amounts of heat by changing its phase, such as changing from a solid to a liquid. To design the new mug, the researchers first created a hollow porcelain shell filled with ribbons of highly conductive aluminum. The aluminum formed a honeycomb structure, which the researchers filled with solid PCM. When the mug is filled with a hot beverage, the PCM absorbs the heat and melts like wax into a liquid. This process cools the beverage down to the optimal temperature. As the beverage cools over time, the PCM slowly releases the stored heat back into the drink, maintaining the optimal temperature for up to 30 minutes.As the scientists note, different drinks have different optimal temperatures. Warm drinks such as coffee and tea are best enjoyed at 58° C (136.4° F), beer tastes best at 7° C (44.6° F), and ice-cold drinks are best at -12° C (10.4° F). Since different types of PCM have different chemical properties and melting temperatures, the scientists can make different mugs for different beverages. The downside for the consumer is that there is not a single mug for hot and cold drinks.The researchers hope that, if they can find a business partner, the PCM mugs could be on sale by the end of the year. However, despite the fact that PCM is relatively inexpensive, the mugs will still probably cost significantly more than most mugs. Besides mugs, PCM could have other interesting applications. For instance, researchers are investigating the possibility of using it to keep perishable foods from spoiling, and even putting it on museum walls to protect paintings in the case of a fire, since PCM is non-flammable. PCM already has commercial uses in construction materials, where it is embedded in walls and ceilings to maintain a comfortable room temperature. Some winter jackets also contain PCM for providing greater warmth. In addition, due to their long-term memory capabilities, PCM could be used for storing computer data without the need for an electric current.via: Spiegel© 2009 PhysOrg.com 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

Thermodynamic analysis reveals large overlooked role of oil and other energy sources

first_imgA newer model of economic growth includes not only capital and labor, but also energy and creativity as production factors. Energy is placed on equal footing as capital and labor. Credit: R. Kümmel. The Second Law of Economics: Energy, Entropy, and the Origins of Wealth Citation: Thermodynamic analysis reveals large overlooked role of oil and other energy sources in the economy (2014, December 31) retrieved 18 August 2019 from https://phys.org/news/2014-12-thermodynamic-analysis-reveals-large-overlooked.html (Phys.org)—The laws of thermodynamics are best known for dealing with energy in the context of physics, but a new study suggests the same concepts could help improve economic growth models by accounting for energy in the economic sphere. Polluting China for the sake of economic growth In neoclassical growth models, there are two main contributing factors to economic growth: labor and capital. However, these models are far from perfect, accounting for less than half of actual economic growth. The rest of the growth is accounted for by the Solow residual, which is thought to be attributed to the difficult-to-quantify factor of “technological progress.”Although neoclassical growth models help economists understand economic growth, the fact that they leave so much economic growth unexplained is a little unsettling. Even Robert A. Solow, the founder of neoclassical growth theory, stated that the neoclassical model “is a theory of growth that leaves the main factor in economic growth unexplained.” Energy, a powerful factor of production In a new study published in the New Journal of Physics, Professor Reiner Kümmel at the University of Würzburg and Dr. Dietmar Lindenberger at the University of Cologne argue that the missing ingredient represented by the Solow residual consists primarily of energy. They show that, for thermodynamic reasons, energy should be taken into account as a third production factor, on an equal footing with the traditional factors capital and labor. (By definition, labor represents the number of work hours per year. Capital refers to the capital stock that is listed in the national accounts, which consists of all energy-converting devices, information processors, and the buildings and installations necessary for their protection and operation. Energy includes fossil and nuclear fuels, as well as alternative energy sources.)The new proposal lies in stark contrast to neoclassical growth models, in which the production factors have very different economic weights, representing their productive powers. In neoclassical growth models, these economic weights or “output elasticities” are set equal to each production factor’s cost share: Labor’s cost share is 70%, capital’s is 25%, and energy’s is just 5%. Real-world implicationsTo test their model on reality, Kümmel and Lindenberger applied it to reproduce the economic growth of Germany, Japan, and the US from the 1960s to 2000, paying particular attention to the two oil crises. In neoclassical models, reductions of energy inputs by 7%, as observed during the first energy crisis in 1973-1975, should have caused total economic output reductions of only 0.35%, whereas observed reductions were up to an order of magnitude larger. By using the larger weight of energy, the new model can explain a much larger portion of the total output reductions during this time. If correct, their findings have major implications. First, the new model doesn’t require the Solow residual at all; this residual disappears from the graphs that show the empirical and the theoretical growth curves. Energy, along with the addition of a smaller “human creativity” factor, accounts for all of the growth that neoclassical models attribute to technological progress.Second, and somewhat unsettling, is the impact that the findings may have in the real world. In 2012, the International Monetary Fund stated in its World Economic Outlook that “…if the contribution of oil to output proved to be much larger than its cost share, the effects could be dramatic, suggesting a need for urgent policy action.” According to the authors’ analysis, the high productive power of cheap energy and the low productive power of expensive labor has implications that we can easily observe. On one hand, the average citizens of highly industrialized countries enjoy a material wealth that is unprecedented in history. On the other hand, cheap, powerful energy-capital combinations are increasingly replacing expensive, weak labor in the course of increasing automation. This combination kills jobs for the less skilled part of the labor force. It is also why far fewer people work in agriculture and manufacturing today than in the past, and more people work in the service sector—although even here, computers and software are replacing labor or causing job outsourcing to low-wage countries. This well-known trend can be understood by the new model’s message that energy is cheaper and more powerful than labor. Where is equilibrium?At the heart of Kümmel and Lindenberger’s model is the concept of thermodynamic equilibrium. As the researchers explain, economies are supposed to operate in an equilibrium where an objective, such as profit or overall welfare, has a maximum. To maximize these objectives, neoclassical economics assumes that there are no constraints on the combinations of capital, labor, and energy. With no constraints, economic equilibrium is characterized by the equality of output elasticities and cost shares, which is one of the assumptions of neoclassical growth models as described above.In their new model, Kümmel and Lindenberger apply the same optimization principles, but also take into account technological constraints on production factor combinations. In reality, a production system cannot operate at more than full capacity, and its degree of automation at a given time is limited by the quantities of energy-conversion devices and information processors that the system can accommodate at that time. Further, legal and social obligations may place “soft” constraints on the production factors, particularly labor.In the new model, these technological constraints on the production factors prevent modern industrial economies from reaching the neoclassical equilibrium where the output elasticities of capital, labor and energy are equal to these factors´ cost shares. Rather, the equilibrium of real-life economies, which are limited by technological constraints, is far from the neoclassical equilibrium.While the model provides a new perspective of economic growth, the ultimate question still remains: what kinds of strategies will stimulate economic growth and reduce unemployment and emissions? Whatever the answer, the results here suggest that it must account for the pivotal role of energy in economic production.”Within the present legal framework of the market, one needs economic growth to ban the specter of unemployment,” the researchers explain. “Energy-driven economic growth, in turn, may lead to increasing environmental perturbations, because, according to the first and second law of thermodynamics, nothing happens in the world without energy conversion and entropy production. And entropy production is associated with the emissions of heat and particles, notably carbon dioxide as long the world uses fossil fuels at the present rate.”Kümmel is also the author of a book on the subject called The Second Law of Economics: Energy, Entropy, and the Origins of Wealth. Explore further More information: Reiner Kümmel and Dietmar Lindenberger. “How energy conversion drives economic growth far from the equilibrium of neoclassical economics.” New Journal of Physics. DOI: 10.1088/1367-2630/16/12/125008 (Left) Economic growth and (right) contributions of the three main production factors to economic growth in Germany in the late 20th century. Credit: R. Kümmel. The Second Law of Economics: Energy, Entropy, and the Origins of Wealth In their analysis, the researchers found that, unlike in neoclassical models, the economic weights of energy and labor are not equal to their cost shares. While the economic weight of energy is much larger than its cost share, that of labor is much smaller. This means that energy has a much higher productive power than labor, which is mainly because energy is relatively cheap while labor is expensive. © 2014 Phys.org Journal information: New Journal of Physics 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

Reviving the languages

first_imgBol Bosh, a website about the diverse languages, literatures and folklore of Kashmir, curated by Asiya Zahoor was launched at Oxford Bookstore Connaught Place in the Capital. Author Namita Gokhale launched the website on 5 August followed by a presentation and discussion with Basharat Ali and Asiya Zahoor.Bol Bosh in Kashmiri refers to communication, in the most endearing way. It aims to focus on those languages and oral and folk literatures in particular that are lesser known. Though these literatures are aesthetically appealing, culturally rich and historically significant, they have a very less or no visibility. By bringing these on a digital platform Bol Bosh aims to make such narratives accessible to the wider world. Some of the languages that are being revived through Bol Bosh are Pashtu, Gojri, Pahari, Dogri, Kohistani, Sheikhagal, Poguli, Shina, Bhaderwahi, Ladhki and Burushaski. Also Read – ‘Playing Jojo was emotionally exhausting’Asiya Zahoor lives and teaches in Baramulla, Kashmir. Her persisting passion for education since childhood led her to volunteer for teaching various schools in adjacent villages of Baramulla in addition to teaching at a colleges. She has known education as a tool of empowerment. Her interest in language and literature drove her to Oxford University. Basharat Ali pursued his Bachelor’s Degree from Government College Baramulla, University of Kashmir. From his childhood he had the urge and desire to contribute to his society by being a change. Ali has dedicated himself selflessly to the development of the society.last_img read more

Its all about Delhi

first_imgDHF (Delhi Heritage Foundation) organised the first talk under the Delhi Heritage Lecture Series on ‘Establishment and Growth of Hindu College in the Walled City: Post 1857 Intellectual Hulchul’ by Kavita Sharma (Former Principal Hindu College), Director IIC at its headquarter on 13 August. The session was a part of elaborate initiatives planned to present the unexplored of Delhi for its own residents and spread awareness. DHF has been set up with a mission to preserve and promote heritage of one of the oldest cities in the country. Also Read – ‘Playing Jojo was emotionally exhausting’The key objectives of DHF are – to preserve and promote the heritage, culture, monuments and history of Delhi and to encourage public involvement in heritage preservation.DHF has signed the Memorandum of Understanding (MOU) with Delhi Walks, a walking tour vertical founded by Sachin Bansal to connect and showcase both the historical and contemporary facets of Delhi as mélange of cultures. Another MOU has been signed with Shoobh Group Welfare Society under the banner of Bharat Gauba, a non-profit community based organisation, which has worked on different social issues and shall be taking Delhi heritage to schools and colleges through a wide array of specially designed programmes. It will soon be announcing a major initiative that includes lectures series, seminars, conferences, workshops and publications.last_img read more

Of classic symphony

first_imgBe all set to be mersmerised by the duet performance by sitar exponent, Azeem Ahmed Alvi and tabla player Ustad Akram Khan Sitar Player on December 21 at the Triveni Kala Sangam at Mandi house in the Capital. Azeem Alvi’s composition has been composed in different taals like rupak, ektaal, teental. Azeem will play raag yaman with alaap jod jhaha. The composition in rupak tala will start after half beat. On the other hand Ustad Akram Khan will accompany the taals on table Azeem Ahmed Alvi, is one of India’s leading and Internationally known artiste in world music. Born in the family of classical Indian music as a tradition for six generations, he is deeply rooted in the Indian classical music and studied under Ustad Mohsin Ali Khan till the age of six. He gained his true potential and skill India’s biggest Sitar living legend, also from this family and his ‘Guru’ Padmashree awarded, Ustad Shahid Parvez Khan and his father  the renowned and respected Sitar maestros Ustad Sayyed Ahmed Alvi. Also Read – ‘Playing Jojo was emotionally exhausting’Only in his twenties, Azeem Ahmed Alvi has established a strong foothold in the contemporary music scene both, in India and abroad. Already known to be one of the foremost sitar players of the world, he aspires to bridge the gap between Indian classical and western contemporary music. Through his musical expertise, he has dabbled in diverse genres like Sufi, Flamenco, Jazz, Electronica and Western Classical music.In 2012, he took his passion for traditional Indian music and the Sitar to a new level with the creation of his NGO, the Raag Mantra Music Foundation. He has recently concluded his 15th European tour with Harry Stojka when he performed at the Jazz Festival in Vienna, Stuttgart in Germany at the World Music Festival, Jazz-Fest in Nurnberg, Germany amongst many others. Also Read – Leslie doing new comedy special with NetflixAkram Khan received his initial training in music from Late Ustad Niazu Khan who was famous for his technical style and guidance. He is also fortunate to have learnt from his great grandfather Ustad Mohd Shafi Khan. He continues his riyas and training under the able guidance of his father Ustad Ashmat Ali Khan. He has also undergone formal training at The Prayag Sangeet Samiti, Allahabad and passed the Sangeet Praveen (Master Of Music) From there apart from Sangeet Visharad at Chandigarh. He has a Bachelor’s degree in Commerce. He is also a top grade artiste from All India Radio, New Delhi.When: December 21 Where: Amphitheater, Triveni Kala Sangam,  Mandi Houselast_img read more