Carbon Nanotube Windmills Powered by Electron Wind

first_img Explore further The proposed (a) nanomotor and (b) nanodrill, where the red inner CNT rotates due to an electron wind. The nanomotor is attached to gold electrodes, which act as electron reservoirs, while the nanodrill has one end contacted to a mercury electrode. Credit: S.W.D. Bailey, et al. Tiny tubes move into the fast lane As Steven Bailey, Ilias Amanatidis, and Colin Lambert explain in a recent issue of Physical Review Letters, the new drive mechanism could be useful for future NEMS (nanoelectromechanical structures) technologies. “[Previously,] thoughts have been directed towards ‘pushing’ the motor to make it turn, whereas our suggestion harnesses an intrinsic property of the device: the change in momentum of electrons or phonons, for example,” Bailey told PhysOrg.com.The researchers describe the proposed nanomotor as a carbon nanotube (CNT) windmill, although the device looks more like a telescope than the conventional spinning blades of a windmill. It consists of a double-walled CNT, where the outer tube is clamped to two external electrodes, and the shorter inner tube is free to move and rotate. In a version called the CNT drill, the outer tube is clamped to just one electrode, while one end of the free inner tube is in contact with a mercury electrode, but is still free to rotate. The devices are called windmills because they’re powered by an applied dc voltage between the electrodes, which produces a “wind” of electrons.As it moves through the CNT, the flow of electrons acquires angular momentum, producing a tangential force that causes the inner nanotube to rotate. The researchers calculated that the electron wind can produce a force that significantly exceeds the inter-wall friction – sometimes by as much as three orders of magnitude. Depending on the applied voltage, the rotating inner tube can reach CNT breakdown velocities of up to 8,000 meters per second.The electron-wind-powered nanomotor could have a range of applications. For instance, by using a voltage pulse to make the inner tube rotate at a specific angle, it could be used as a switch or memory element in nanoscale magnetic memory devices; or, by putting the CNT in contact with a reservoir of atoms or molecules, the nanomotor could act as a nanofluidic pump.The physicists also suggest that the motor could be powered in different ways. In one possibility, the electrodes could be replaced with reservoirs of atoms or molecules. Then, an applied pressure difference could drive the atoms or molecules across the CNT, and their angular momentum could cause the inner tube to rotate. Similarly, a temperature difference between the ends of the CNT could create a flux of phonons that could also drive the motor. Other CNT-based nanomotors have been developed, including multi-walled CNTs with a similar structure to the CNT windmill. However, these previous designs have been powered by electrostatic forces that require metallic plates and gates, which aren’t needed in the new design. The researchers hope that the efficiency and simplicity of the CNT windmills will provide advantages over electrostatic and other nanomotors in the future.“The capability to engineer nanoscale motors is at the same stage as that of microscale motors in the 1990s,” Bailey said. “The manufacturing techniques to deal with the very low dimensions are always playing catch up with experimental groups, which are making very rapid progress, and we predict that to test out the CNT windmill will not require much change to established procedures within these groups. Indeed, there should be much less construction involved in making the nanomotor devices. The engineering simplicity of the CNT windmill will be the greatest advantage in the future.”More information: Bailey, S.W.D; Amanatidis, I.; and Lambert, C.J. “Carbon Nanotube Electron Windmills: A Novel Design for Nanomotors.” Physical Review Letters 100, 256802 (2008).Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Theoretical physicists from Lancaster University in the UK have designed a nanomotor that operates by a novel mechanism: an electron wind. Citation: Carbon Nanotube Windmills Powered by ‘Electron Wind’ (2008, July 8) retrieved 18 August 2019 from https://phys.org/news/2008-07-carbon-nanotube-windmills-powered-electron.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.last_img read more

Stretchable Nanotube Films May Advance Medical Electronics Update

first_img(PhysOrg.com) — One of the issues hindering the development of medical electronic devices capable of being implanted in the human body is the lack of suitable materials. Most semiconducting materials are stiff and brittle, while human tissue is soft and pliable. Scientists at the University of California, Los Angeles (UCLA), appear to have taken a key step forward in implantable electronics research. A nanotube film placed over printed “UCLA” lettering prior to stretching. Image courtesy Qibing Pei. Will carbon nanotubes replace indium tin oxide? Explore further The group studied a very thin nanotube-based material and measured how it responds electrically and optically to extreme strains. As described in the April 22, 2009, online edition of Applied Physics Letters, they found that the material continues to conduct electricity when subjected to strains of more than 700 percent – that is, stretched to seven times its starting dimensions – ceasing to perform only when cracks developed.Implantable medical electronic devices can monitor a variety of bodily functions, including blood pressure, temperature, fluid flow; they can also sense chemical, electrical, and even magnetic properties within the body. But certain devices would require significant flexibility without compromising performance. Currently, the best materials for electronic medical devices develop cracks under less than 10 or 20 percent strain. “Using nanotubes is an obvious solution to the problems that have faced the development of these materials because they have high length-to-width ratios, which means they can bridge the cracked regions to maintain conductivity,” said co-author Qibing Pei, a UCLA materials science professor, to PhysOrg.com.Thin films of randomly distributed carbon nanotubes have been widely studied for a variety of electronics applications. They have displayed a variety of interesting and useful properties, such as very high flexibility, which is key for implantable medical electronics. There have been conflicting studies regarding the toxicity of carbon nanotubes, although recent studies concluded that they are not toxic to mice.The UCLA team first deposited the nanotubes onto a highly elastic substrate so that the films could be properly stretched. They performed the stretching slowly, straining the material both uniformly – with equal strain applied to each end of the film – and non-uniformly. They applied a voltage across the film as it was stretched, measuring the changing electrical response.The group also studied the optical properties of the films, which are transparent before stretching but are rather dark. Prior to stretching, they placed the films over printed letters, observing that the letters appear crisp. As strain is increased the letters became “fuzzy”; simultaneously, the films lightened in color.Using a scanning electron microscope, the group investigated the structural changes that occur during stretching and how they affect the films’ electrical and optical properties. When the nanotubes are spray-deposited, they appear to be uniformly distributed but actually form clusters. As strain is applied the clusters begin to break up, but because the nanotubes are long and thin they form connections between the clusters, which do not disappear but rather become less dense. Thus, the conduction pathways remain intact.The fuzziness that appears in the films is due to the spreading out of the nanotubes, which absorb and scatter light. The color change is due to the thinning of the films, which allows more light to pass through.The researchers say that the films could be made to conduct under even greater strains, with the development of ways to more uniformly deposit the nanotubes onto the substrate or applying a top coat to the films to fill in cracks.More information: Applied Physics Letters 94, 161108 (2009), http://link.aip.org/link/?APPLAB/94/161108/1Copyright 2009 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. 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: Stretchable Nanotube Films May Advance Medical Electronics (Update) (2009, May 4) retrieved 18 August 2019 from https://phys.org/news/2009-05-stretchable-nanotube-advance-medical-electronics.htmllast_img read more

Sony unveils 3D and color epaper displays at this weeks SID 2011

first_img Sony’s 13.3 inch flexible color e-paper. Explore further Sony’s 3D displays come in a 10 inch and 23 inch size and can deliver a 3D image without the use of any special glasses. The method uses a backlight for 3D images positioned between an LCD panel and a backlight for normal 2D images. Switching between 2D and 3D is accomplished by lighting one of the two backlights.The backlight for the 3D images are LED’s placed on the light guide plate and its edges. On the light guide plate scatter patterns are produced at even intervals in the horizontal direction to direct light to the outside. More information: At the 49th SID International Symposium, Seminar & Exhibition Sony unveiled their new 3D glasses free display and flexible color e-paper. 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. Sony’s 3D 10 inch and 23 inch displays deliver 3D images without the use of any special glasses. The 3D effect is produced by the LED light sources being reflected on the scatter patterns to go to the back side of the panel as if lights are partially controlled by using “parallax barriers.” The result shows different images to the right and left eye. Sony’s 24-inch 3D LCD display has six viewpoints, and its pixel count is 960 x 360, and its brightness is 86.1cd/m2. 3D images are best viewed between distances of 80 to 160cm. The 2D mode, the pixel count of the display becomes 1,920 x 1,080 and has a brightness of 192cd/m2.Sony states that the new method can be applied to displays between 4 to 30 inches and hopes to commercialize it within a few years.center_img via Tech-On e-paper, Tech-On 3D display Sharp Introduces 3D LCD Color Monitor that provides a stereoscopic display Citation: Sony unveils 3D and color e-paper displays at this week’s SID 2011 (2011, May 20) retrieved 18 August 2019 from https://phys.org/news/2011-05-sony-unveils-3d-e-paper-week.html © 2010 PhysOrg.com (PhysOrg.com) — Sony unveiled a 13.3 inch flexible color e-paper device and two glass free 3D displays. The announcement was made at the 49th SID International Symposium, Seminar & Exhibition which is the world’s largest academic conference on display technologies. The conference is being held this week in Los Angeles, CA (USA). Sony’s 13.3 inch flexible color e-paper has a thickness of 150 microns and weighs 20g and uses a plastic substrate. The e-paper display has a 13% color gamut (NTSC), a reflectance of 10% and a 100,000:1 contrast ratio.The display’s 800 x 1200 pixel array consists of red, green, blue, and white sub-pixels. The sub-pixel measures 169 microns x 169 microns and the resolution and gradation of the screen are 75ppi and 16, respectively.The e-paper display is manufactured by applying adhesive to the glass substrate and attaching a plastic substrate. Amorphous TFTs are then formed on it with a180°C or lower temperature process. The plastic substrate is then finally removed from the glass substrate.last_img read more

Team suggests sublimating ice to propel CubeSats

first_img © 2015 Phys.org Explore further MIT lab developing ion microthrusters for cubesats Citation: Team suggests sublimating ice to propel CubeSats (2015, March 19) retrieved 18 August 2019 from https://phys.org/news/2015-03-team-sublimating-ice-propel-cubesats.html More information: Conceptual design of a low-pressure micro-resistojet based on a sublimating solid propellant, Acta Astronautica, Volume 108, March–April 2015, Pages 30–39. www.sciencedirect.com/science/ … ii/S0094576514005001AbstractIn the current and future trend towards smaller satellite missions, the development of a simple and reliable propulsion system with performance and characteristics in line with the typical requirements of nano-satellites and CubeSats plays a crucial role for enhancing the capabilities of this type of missions. This paper describes the design of a micro-resistojet using water stored in the frozen state (ice) as propellant, operating under sublimation conditions at low pressure. The low operating pressure allows for using the vapor pressure of ice as the only method of propellant feeding, thereby allowing for extremely low thrust and electric power usage. The results of an extensive set of numerical simulations for optimizing the thruster geometry in terms of power ratio and specific impulse produced are discussed. In addition, the design of the complete propulsion system is described. It makes use of a limited number of moving parts and two power sources, one in the thruster to increase the propellant temperature and one in the tank to maintain the propellant storage conditions. Results show that the proposed design represents an alternative option capable of meeting the typical requirements of small satellite missions by means of an intrinsically green propellant such as water, with the pressure inside the system never exceeding 600 Pa. Optimization results showed an optimum thrust to power ratio in range 0.2–1.2 mN/W for an expansion slot aspect ratio of 2.5.via Newscientist Tiny satellites that have earned the nickname CubeSats, have become very popular in recent years—their small size allows for many of them to be launched from one rocket, dramatically reducing costs. But they all have one thing in common—lack of a propulsion system. That means they are not able to maintain an orbital altitude, which dooms them to reentry after just a few months. It also prevents them from being sent out into deeper space, such as to the moon, or even to other parts of the solar system. Thus far, several projects have been announced with researchers looking to find a way to balance weight and size relative to the amount of thrust that can be generated. In this new effort the researchers think the solution is to use and ice and a solar collector.The team calls its system Ion Electrospray Propulsion System—it would work by taking advantage of ice sublimating in a space environment. The water molecules would be directed at a plate heated by solar power, which would cause them to move faster—directing them through a nozzle would generate just enough thrust, the team believes, to allow for controlling a CubeSat. The problem of course is how to keep the water frozen while a CubeSat is sitting on a launch-pad. The team does not have an answer for that but believe that if a solution can be found, their engine would be feasible—it would also require just five ounces of ice. That tiny bit of water might present another problem however, as it would account for ten percent of the allowable weight of a CubeSat, meaning there would be less for electronics or other gear. Also there is an issue of power utilization—heating the plate would take away from power that is currently used for other hardware.Whole fleets of CubeSats or CubeExplorers doing both academic and amateur research is an exciting proposition, perhaps if ice does turn out to be the best fuel for them, NASA or commercial rocket companies will start providing freezing compartments for whole crates of CubeStas as part of a package deal. 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. CubeSats launched from the International Space Station on 4 October 2012. Credit: NASA (Phys.org)—A trio of researchers affiliated with Delft University in The Netherlands, has come up with a new way to provide propulsion for CubSats—use frozen water as fuel. In their paper published in Acta Astronautica, the team outlines their design and suggest there is just one hurdle still standing in their way—a means of keeping the water frozen while a CubeSat is awaiting launch.last_img read more

Food is fair in Surajkund

first_imgThe most sought after mela is back again. Touted as one of the most entertaining crowd pullers, SurajKund International Crafts Mela brought together some delectable dishes from across the India in Haryana this year.The food court spread in the sprawling area of the mela has a fantastic range of cuisines with a regional uniqueness. To keep special care of the health and hygiene of the visitors, the authority has ensured that cleanliness is maintained and there is a provision of several garbage bins in the mela premises. Drinking water has also been made available at various places for the convenience of the visitors. Also Read – ‘Playing Jojo was emotionally exhausting’Focussing on the food stalls which display specialities and delicacies of their respective states. From Mumbai’s bhelpuri to Jaipur’s Dal Bhatti Churma and theme state Karnataka’s Sukka Chicken, Masala Dosa and filter coffee and Bihar’s Lithi Chokha, the mela has different state cuisines to be relished. Aloo tikki, Golgappe, Chaat, flavoured milk and Pav Bhaji are the most popular street foods at the Mela. Bhelpuri and Kulfi are other food items high on demand. Also Read – Leslie doing new comedy special with NetflixThe cuisine of the theme state, Karnataka offers a wide variety of food items, which include Bijapur Mirchi, Chakkali, Khadak Rotti, Shavige Bath, Uppittu, Chicken Sukka, Akki Rotti, Kyatsandra Ttiol, Gokak Karadantu and Dharwad Pedha.‘People are very happy to eat authentic South Indian delicacies at out stall. They take keen interest in knowing about our recipes,’ said K. Seenappa, Assistant General Manager, Karnataka State Tourism Development Corporation. The wines of Karnataka are also being displayed at the Mela purely for promotional purposes. Praveen Deshpande at the Karnataka wine counter, says, ‘The concept of manufacturing wines is relatively new in India, so we are aggressively marketing our wines in the Northern region, as people here are fond of wine and even the climate is well suited for wine consumption.’ He further added that an array of wines like Cabernet Sauvignon, Martot and Cabernet Franc are being produced in their state from French varieties of grapes spread over an area of 2,000 acres.Hot Gulab Jamuns, Gajar Ka Halwa teamed up with ice cold chuskis are some desserts served. The famous Banarasi paans adds to a mouth freshening experience. Cultural performances in the food court add to the wholesome entertainment.DETAILAt: Surajkund Mela Grounds, FaridabadOn till: 15 FebruaryTimings: All daylast_img read more

Maha CLP authorises Sonia Gandhi to nominate leader

first_imgMaharashtra Congress legislature party met here on Thursday and authorised party president Sonia Gandhi to nominate their leader even as former chief minister Prithviraj Chavan said he was not in the race for the post.A one-line resolution moved by state party chief Manikrao Thakre authorising Sonia Gandhi to select the new CLP leader was adopted unanimously.Earlier, leader of the Congress party in Lok Sabha Mallikarjun Kharge, central observer for the election, met the legislators individually to ascertain their views on the new CLP leader.last_img

Wenger rues lack of efficiency

first_imgA subdued and sombre Arsene Wenger was left to rue Arsenal’s lack of efficiency after his team lost 2-1 at home to Manchester United on Saturday in a game they dominated. ‘We have not dominated many games against United like we did today but we were not efficient enough and made defensive mistakes. We had plenty of opportunities to win the game and we are very disappointed. We were a bit naive,’ Wenger told a news conference. Wenger’s misery was compounded by injuries to midfielder Jack Wilshere and goalkeeper Wojciech Szczesny, who were both forced off in the second half.  ‘Jack has an ankle injury. I don’t know how bad it is yet. Wojciech is not bad,’ he said.Arsenal have slipped to eighth in the EPL table, 15 points behind Jose Mourinho’s Chelsea.last_img

Books restoring a legacy

first_imgThese are the times when photographs  are digital and they are saved in the latest gadgets and written works are coming in an e-book format. Film-maker and actor Aparna Sen released a book on  photography titled ‘IMAGES’ and politician Jaya Jaitly released a book on contemporary art titled ‘VOICES’ at the India Habitat Centre on Monday.Edited by art historian and curator Dr Alka Pande, the books produced under the aegis of India Habitat Centre were released to also celebrate the completion of 15 years of the Visual Arts Gallery, which has showcased and promoted some of the most seminal exhibitions over the last fifteen years. Also Read – ‘Playing Jojo was emotionally exhausting’The book ‘IMAGES’ features seven seminal essays on the evolution, growth and importance of the art of photography by names like Bandeep Singh, Robert Pledge, Nathalie Herschdorfer and Ashim Ghosh apart from featuring works of eleven photographers who have been past winners of the annual Habitat Photography award since 2003.The book ‘VOICES’ features twenty decisive essays on the Indian and world contemporary art by influential names like Nissar Allana, Jaya Jaitly, Alka Pande, Jonathan Faiers, Raj Liberhan, Diana Campbell Betancourt, Peter Nagy among others apart from featuring the top twenty exhibitions at Visual Arts Gallery over the last 15 years. Also Read – Leslie doing new comedy special with NetflixAfter the book release, eminent photographer Bandeep Singh read out excerpts from IMAGES which was followed by a book reading from his book NO COUNTRY by author Kalyan Ray. Young photographers who have been the past winners of India Habitat Centre Photography Fellowship were then awarded by Raj Liberhan, former director, IHC.Rakesh Kacker (Director, India Habitat Centre), Alka Pande (curator), Dr Linus Von Castelmur (Ambassador of Switzerland to India and Bhutan), Aparna Sen (filmmaker and actor), Jaya Jaitly (politician), Kalyan Ray (author), Bandeep Singh (photographer), Aditya Arya (photographer), Sandeep Biswas (artist), Avinash Pasricha (photographer) with wife Kiran, Madhu Jain (columnist), Humra Querishi (columnist), Harinder Singh with wife Kirandeep Kaur (art patron) among others were present on the occasion.last_img read more

Timely police intervention saves two minors from rogue appcab driver

first_imgKolkata: Two minor girls were saved on time from being taken away by an app-cab driver, thanks to the prompt action of two traffic sergeants from Shyambazar Traffic Guard.The incident occurred on Wednesday evening near Shyambazar Seven Point crossing. Sources informed that two women from Rajasthan aged about 50 years were seen crying and screaming near R G Kar Road and Raja Dinendra Street crossing on Wednesday evening around 6:10 pm. On seeing them, on-duty traffic sergeant of Shyambazar Traffic Guard Kajal Das went to the ladies. Also Read – Rain batters Kolkata, cripples normal lifeOn enquiring, he was told that they had booked an app-cab from Shyambazar Seven Point crossing for Mechhua in Burrabazar. However, after boarding the cab along with two minor girls of their family, the driver drove took the cab along R G Kar Road instead of going towards Burrabazar. When the ladies questioned the driver on why he took a wrong route, the driver allegedly stopped the cab near Raja Dinendra Street and asked them to get down as he would not go and cancelled the trip. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedHaving no other choice, when the ladies got down from the cab, the driver sped off with the two minors being inside car. On hearing the incident, Das immediately checked with their booking and noted the last four digits of the cab’s registration number. He quickly informed the Shyambazar Traffic Guard about the incident. Meanwhile, the phone number of the driver was fortunately their on call list. When Das called the driver, he denied being the same. Just after that when an police officer from the traffic guard called him, he informed that he had left the two minors near R G Kar canal side road. After Das was informed about the development, he went there and found the two minor girls crying on the road. Later, they were handed over to their guardians. Das requested the two ladies to lodge a complaint but they denied to do so.last_img read more

Mamata pays tribute to bravehearts of Mumbai terror attacks

first_imgKolkata: On the 10th anniversary of the 26/11 Mumbai terror attacks, West Bengal Chief Minister Mamata Banerjee on Monday paid tribute to those who laid down their lives to protect others. She also extended sympathies to those who lost their dear ones in the attacks carried out by 10 members of Lashkar-e-Taiba, a Pakistan-based terrorist organisation, in 2008. “On the 10th anniversary of the 26/11 attack, my sincere tribute to those who lost their lives on that day. Also Read – Rain batters Kolkata, cripples normal life Salutes to the police and military personnel, and civilians, who put their lives on the line to save people. Heartfelt sympathies with the families who lost their dear ones,” Banerjee said in a Twitter post on Monday. Terrorists carried out a string of coordinated shooting and bombing attacks that began on November 26 and lasted until November 29, 2008 in which more than 159 people, including 9 attackers were killed and over a hundred wounded in the business capital of the country.last_img read more