Citation: Suspension bridge design may not be the best (2010, January 15) retrieved 18 August 2019 from https://phys.org/news/2010-01-suspension-bridge.html The amount of cable that can be replaced depends on the level of compression the material can withstand. If it can take tension and compression to an equal degree, using a net can reduce the amount of material needed to build the bridge by 0.3%. Other structural engineers have pointed out that this small reduction in material may not provide an economic justification for making a more complicated bridge, since they would undoubtedly be more expensive to manufacture.The work is published in the January edition of the Structural and Multidisciplinary Optimization journal. More information: Optimum structure to carry a uniform load between pinned supports, Structural and Multidisciplinary Optimization, www.springerlink.com/content/v4543505v4721655/ Terrorist-resistant bridge is developed 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. © 2010 PhysOrg.com (PhysOrg.com) — A team of structural engineers from the University of Sheffield in the UK say the assumptions originating with 17th century Dutch engineer Christiaan Huygens may need to be re-examined. Huygens assumed the best design for a suspension bridge was based on towers and simple cables hanging between them to support the weight, but the Sheffield group say a more complex design using less material would be more efficient. Forms found to be more optimal than a parabola to carry a uniform loadbetween pinned supports (compressive elements shown in blue). Image credit: Matthew Gilbert The Huygens idea is behind well-known suspension bridges such as the Golden Gate bridge in San Fancisco and the Akashi-Kaikyō Bridge in Japan, which is around 700 meters longer. Basically, the road or railway is suspended from thin hangers dropping from two cables that stretch between the two towers. The cables automatically form a U-shaped curve, or parabola, and this arrangement has been assumed to be the most efficient.Matthew Gilbert and his colleagues from the Department of Civil and Structural Engineering noted that the calculations assumed the cables could withstand tension but not compression, but in reality both forces are in play. They developed a numerical layout optimization program to check the optimal design and were surprised to find Huygens’ parabolic arch rib or cable was not optimal, and the amount of material needed for the cabling could be reduced if the ends were replaced with a network of truss bars known as the “Hencky net”. Gilbert said they expected the parabolic design to be confirmed and they tried to work out what was wrong when their software continually nominated the more complex design. “It ended up that the only option was that the current wisdom was wrong,” Gilbert said.
(a) A schematic view of the ALPHA trap. Penning trap electrodes are held at ~9 K, and have an inner diameter of 44.5 mm. A three-layer silicon vertex detector surrounds the magnets and the cryostat. A 1 T base field is provided by an external solenoid (not shown). An antiproton beam is introduced from the right, while positrons from an accumulator are brought in from the left. (b) The magnetic field strength in the y-z plane (z is along the trap axis, with z=0 at the centre of the magnetic trap). Green dashed lines in this and other figures depict the location of the inner walls of the electrodes. (c) The axial field profile, with an effective trap length of ~270 mm. (d) The field strength in the x-y plane. (e) The field strength profile along the x-axis. Image credit: ArXiv paper (see ref. below) (PhysOrg.com) — Seventeen minutes may not seem like much, but to physicists working on the Antihydrogen Laser Physics Apparatus (ALPHA) project at the CERN physics complex near Geneva, 1000 seconds is nearly four orders of magnitude better than has ever been achieved before in capturing and holding onto antimatter atoms. In a paper published in arXiv, a team of researchers studying the properties of antimatter, describe a process whereby they were able to confine antihydrogen atoms for just that long, paving the way for new experiments that could demonstrate properties of antimatter that until now, have been largely speculation. 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. The process works by cooling the antiprotons that when combined with positrons, are used to make the antihydrogen, which reduces the energy in the resulting antimatter and allows for more of it to be confined in a magnetic trap, and then held there in a cloud for a period of time.One of the big questions in physics is whether antihydrogen atoms occupy the same energy levels as hydrogen; others of course want to know how it reacts to gravity, as some have speculated that antihydrogen might actually fall up, or behave in other unexpected ways. The experiments going on at CERN might just answer both those questions, and more.The idea of the specialness of antimatter has become a fixture of modern science fiction books, magazines and especially television and movies, creating in the public mind an oftentimes distorted image of what harnessing antimatter might bring. Thus, any new advances such as those happening at CERN tend to incite headlines that invite even more speculation.At any rate, in the experiment, the researchers were able to trap 309 antihydrogen atoms, up from the previous best of just 38, which means the team is learning to both capture more of them and to hold on to them longer before collisions with various trace gasses causes them to be annihilated, or in some cases to become energized enough to escape the magnetic field. Up next for the ALPHA team are plans to cool a small bunch of antihydrogen atoms in such a way as to allow them to watch as it either rises or falls due to gravity, thus answering one of the more exciting questions regarding antimatter, in perhaps just the next few months. New technique for antihydrogen synthesis promises answers to mysteries of antimatter Explore further © 2010 PhysOrg.com More information: Confinement of antihydrogen for 1000 seconds, arXiv:1104.4982v1 [physics.atom-ph] arxiv.org/abs/1104.4982AbstractAtoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond. Antihydrogen, made entirely of antiparticles, is believed to be stable, and it is this longevity that holds the promise of precision studies of matter-antimatter symmetry. We have recently demonstrated trapping of antihydrogen atoms by releasing them after a confinement time of 172 ms. A critical question for future studies is: how long can anti-atoms be trapped? Here we report the observation of anti-atom confinement for 1000 s, extending our earlier results by nearly four orders of magnitude. Our calculations indicate that most of the trapped anti-atoms reach the ground state. Further, we report the first measurement of the energy distribution of trapped antihydrogen which, coupled with detailed comparisons with simulations, provides a key tool for the systematic investigation of trapping dynamics. These advances open up a range of experimental possibilities, including precision studies of CPT symmetry and cooling to temperatures where gravitational effects could become apparent.via Technology Review Citation: CERN scientists confine antihydrogen atoms for 1000 seconds (2011, May 4) retrieved 18 August 2019 from https://phys.org/news/2011-05-cern-scientists-confine-antihydrogen-atoms.html
More information: T.M. Lu, N.C. Bishop, T. Pluym, J. Means, P.G. Kotula, J. Cedarberg, L.A. Tracy, J. Dominguez, M.P. Lilly and M.S. Carroll, “Enhancement-mode buried strained silicon quantum channel quantum dot with tunable lateral geometry,” Applied Physics Letters (2011). Available online: link.aip.org/link/doi/10.1063/1.3615288 Copyright 2011 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. Citation: Could silicon be ideal in quantum computing? (2011, September 16) retrieved 18 August 2019 from https://phys.org/news/2011-09-silicon-ideal-quantum.html Explore further One way to reduce the noise in a quantum system is to use silicon. “Silicon spins have long coherence times. The noise is reduced with silicon, and that is an advantage for this type of quantum computing, since you want to maintain coherence for as long as possible. However, it’s been a challenge to isolate and manipulate silicon spins,” Carroll explains.In order to find a way to isolate and control silicon spins, Carroll, a scientist at Sandia National Laboratories in Albuquerque, New Mexico, has been working with a team. One member of the team, Tzu-Ming Lu, has been helping with the idea of controlling the number of spins with a gate, rather than using doping methods. The work on this project is published in Applied Physices Letters: “Enhancement-mode buried strained silicon channel quantum dot with tunable lateral geometry.”“Increasing the distance between the spins and defects is part of the benefit of this process,” Lu explains. “One of the ways to get spins is to use doping to provide electrons. However, the defects are closer. Instead, we use a gate in an alternative enhancement mode approach.”Lu’s alternative enhancement mode technique was demonstrated during his time as a graduate student at Princeton; it set a world record in mobility. However, the set up was too big to be used effectively for quantum computing. “What we’ve done is taken the large scale field effect transistor structure, and make it into a few-electron quantum dot,” Carroll says. “We squeeze it down for better control of single electrons in this system.”The structure, rather than being a single quantum dot, is actually a double quantum dot. “The dots are placed next to each other, and this gate structure makes it easier to control the spins in the device,” Carroll explains.But why the focus on silicon? Well, as Carroll mentions earlier, the coherence time is longer. There is less noise at low temperature when silicon is used. Caroll and Lu also point out that there is already a solid silicon infrastructure. “We already have silicon foundries that can build the device,” Lu says. “People are used to working with silicon, and so you have very clean environment for the electrons, further reducing unintended noise sources.”Now that some control over these silicon quantum dots has been demonstrated in a few-electron device, the team at Sandia is ready to move on to the next steps. “We aren’t sure that our device is small enough yet,” Carroll says. “Additionally, there was an instability in this particular device. We’ve worked through a new design, and we want to check to make sure that the stability issue is gone.”“Progress is being made in this area, and we’re not the only ones,” Carroll continues. “Silicon is a promising approach to quantum computing because of the long coherence times. This materials approach to isolating and controlling spins is very promising and it could allow even more people to realize the benefits of using silicon in quantum computing.” Creating a pure spin current in graphene (PhysOrg.com) — “Quantum computing could provide a way to significantly speed up the way we process certain algorithms,” Malcolm Carroll tells PhysOrg.com. “The primary issue, though, is that you need a well controlled two-level system.” He also points out that problems exist in terms of noise in quantum computing. One of the essentials in some models of quantum computing is utilizing the “spin” of certain electrons. Controlling the spins in GaAs quantum dots has advanced to a fairly sophisticated point, but there is still the issue of noise. 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.
© 2017 Phys.org More information: Damien Sorigué et al. An algal photoenzyme converts fatty acids to hydrocarbons, Science (2017). DOI: 10.1126/science.aan6349AbstractAlthough many organisms capture or respond to sunlight, few enzymes are known to be driven by light. Among these are DNA photolyases and the photosynthetic reaction centers. Here, we show that the microalga Chlorella variabilis NC64A harbors a photoenzyme that acts in lipid metabolism. This enzyme belongs to an algae-specific clade of the glucose-methanol-choline oxidoreductase family and catalyzes the decarboxylation of free fatty acids to n-alkanes or -alkenes in response to blue light. Crystal structure of the protein reveals a fatty acid–binding site in a hydrophobic tunnel leading to the light-capturing flavin adenine dinucleotide (FAD) cofactor. The decarboxylation is initiated through electron abstraction from the fatty acid by the photoexcited FAD with a quantum yield >80%. This photoenzyme, which we name fatty acid photodecarboxylase, may be useful in light-driven, bio-based production of hydrocarbons. Using a nickel catalyst with hydrocarbons to make fatty acids Explore further Light-activated enzymatic hydrocarbon production. Credit: (c) A. Kitterman / Science, DOI: 10.1126/science.aao4399 As Scrutton notes, it is rare for photocatalysis to be used in biologically based manufacturing processes. This is due mainly to a lack of biological material that reacts to light in ways that would make them useful in such applications. Notably, many organisms do respond to light, of course, but very few enzymes used by such organisms use light as a direct energy source. In this new effort, the researchers have found an exception—an algal photoenzyme that converts fatty acids to hydrocarbons using blue light and a riboflavin cofactor. The hydrocarbons produced could conceivably be used as an energy source if the procedure can be scaled.The enzyme was found in the alga Chlorella variabilis and is referred to by the team as a fatty acid photodecarboxylase (FAP), and it works in conjunction with the cofactor flavin adenine dinucleotide (FAD). The team found that the FAP enzyme does its work by uniting the biocatalytic and photoreceptor properties of flavin to catalyze fatty acids through radical chemistry. The result is the removal of carboxyl groups from fatty acids, resulting in the formation of alkanes.The team reports that they observed the enzyme in action after applying blue light to a protein they had expressed through a sample of E. coli. They also reconstructed the enzyme’s crystal structure as a means for discovering how it was bound to fatty acids during catalysis. They further suggest that their work hints at other flavoenzymes might also be phtoenzymes, just waiting to be discovered. (Phys.org)—A team of researchers affiliated with several institutions in France has discovered an algal photoenzyme that uses blue light to convert fatty acids to hydrocarbons. In their paper published in the journal Science, the team describes their work and the possibility of using their findings as a means for providing a new hydrocarbon energy source. Nigel Scrutton with the University of Manchester offers a Perspective piece in the same journal issue outlining the struggle to harness photochemistry in biology-based manufacturing processes along with overview of the work done by the team in France. Journal information: Science Citation: An algal photoenzyme that uses blue light to convert fatty acids to hydrocarbons (2017, September 1) retrieved 18 August 2019 from https://phys.org/news/2017-09-algal-photoenzyme-blue-fatty-acids.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.
New approach to measure fluid drag on the body during swimming Swimming and flying animals are optimally adapted for cruising through their environments, producing thrust via propulsors—wings for birds and caudal fins for fish. Over millions of years, the morphology of these animals evolved for maximally efficient cruising, and about 30 years ago, researchers proposed that most swimmers cruise within a narrow range of Strouhal numbers—these are dimensionless numbers describing oscillating flow. And more recently, researchers determined that flying animals cruise in the same range of Strouhal numbers. More information: Daniel Floryan et al. Efficient cruising for swimming and flying animals is dictated by fluid drag, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1805941115AbstractMany swimming and flying animals are observed to cruise in a narrow range of Strouhal numbers, where the Strouhal number St=2fA/USt=2fA/U is a dimensionless parameter that relates stroke frequency f, amplitude A, and forward speed U. Dolphins, sharks, bony fish, birds, bats, and insects typically cruise in the range 0.2 Journal information: Proceedings of the National Academy of Sciences Swimmers and fliers can be decomposed into thrust-producing (orange) and drag-producing (blue) parts, with the propulsor aptly represented by an oscillating airfoil. Credit: (c) Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1805941115 Explore further Specifically, for swimming and flying animals, the Strouhal number is defined as St=f / U*A, where f is the oscillation frequency, U is the flow rate, and A is the oscillation amplitude. And the narrow range of Strouhal numbers in which swimming and flying animals cruise is 0.2 < St < 0.4.OK. So why is this narrow range of numbers the most efficient? Daniel Floryan, Tyler Van Buren and Alexander J. Smits, mechanical engineers at Princeton University, conducted a study into the efficiency of swimming and flying animals in order to answer that question. They used an experimental setup derived from earlier studies, which consisted of an airfoil in a water tunnel. The airfoil made biologically relevant heaving and pitching motions that were measured by encoders. The researchers performed experiments over all possible combinations of kinetic parameters and analyzed the resulting data mathematically.Since drag can never be completely eliminated, perfect efficiency is not possible. But the animals selected as the fittest have evolved to a narrow range of highly efficient parameters.A swimming animal at a constant velocity creates thrust with its caudal fin, and experiences drag produced by two sources: its body, and the "offset" drag caused by the propulsor frontal area projected over its range of motion. For flying animals, the physics are somewhat different since their propulsors need to resist gravity in addition to providing thrust. However, the need to produce lift doesn't affect the physics of propulsion and drag when the animal is at a steady cruising speed. In previous studies, researchers suggested that large-amplitude motions set the Strouhal number for efficient cruising. The authors of the current study argue that the amplitude sets the total efficiency without dictating the optimal Strouhal number. Instead, the authors write, "the offset drag is crucial in determining the low Strouhal behavior and setting the particular Strouhal at which peak efficiency occurs."Drag turns out to be key. Based on their analysis, the researchers conclude that the range of Strouhal numbers that defines highly efficient cruising for swimming and flying animals is largely determined by the fluid drag on fins and wings. "In other words," the authors conclude, "energetic considerations set the kinematics of the propulsor to the most efficient one, and the net thrust of the propulsor at peak efficiency balances the drag of the body to set the cruising speed."
For the purpose of revival of ancient eroding art in jewellery making and to give creative freedom to the craftsmen, Asha Kamal Modi started this new concept in the year 1988.Out of 100000 unemployed artisans in India, she has been able to provide jobs opportunity and livelihood to more than 900 artisans so far which is providing bread and butter to their family.The foundation reaches out to the rest of the country by saluting eminent personalities and achievers who have contributed to the nation in their respective fields by giving them the Art Karat Award for Excellence. The glittering award ceremony is something to look forward to in the upcoming weeks. Shubha Mudgal will also be performing at the event Also Read – ‘Playing Jojo was emotionally exhausting’The list awardees for this year include – Kiran Bedi (Social Service), Kiran Chopra (Social Service), Shallu Jindal (Kuchipudi), Shubha Mudgal (Vocal Music), Pt. Birju Maharaj (Kathak), Rohit Bal (Fashion Designer), Sanjay Bhattacharya (Painter), Shyama Chona (Education), Aruna Dalmia (Social Service), Prathibha Prahlad (Bharatnatyam), Shovana Narayan (Kathak), Bhajan Sopori (Santoor), Vandana Luthra (Beauty and Wellness), Promila Saraf (Social Service), William Dalrymple (Writer), Rajesh Bedi (Photographer), Nalini Singh (Writer/ Media), Shujaat Khan (Sitar), Bubbles Sabharwal (Theater), Sushil Chaudhry (Eye Care), Umesh Aggrawal (Documentary Film Making) and others. WHERE: Kamani Auditorium WHEN: 19 February, 5:45 pm onwards
Kolkata: A person was critically injured when he was hacked with a knife on Sunday night, after protesting against the molestation of his wife. The incident occurred at Canal Road area in Behala. A critically injured Binod Sau has been admitted to MR Bangur Hospital. Behala police station has arrested one Babu Saheb Jha, who happens to be the neighbour of the victim.According to sources, Jha had been making advances towards Binod’s wife for some days and had not paid heed to the latter’s repeated pleas. Also Read – Heavy rain hits traffic, flightsOn Sunday night, Babu passed lewd comments while Binod was going out with his wife Ruby. When Binod protested, there was a heated verbal exchange and then the duo got involved in a scuffle. Amidst the confusion, Babu took out a knife that he was carrying and stabbed Binod in the stomach.Binod’s wife raised a cry and the people in the neighbourhood rushed to the spot and took a profusely bleeding Binod to MR Bangur Hospital. Meanwhile, Babu fled from the spot. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedA complaint was lodged by the victim’s wife, on the basis of which police arrested Babu in the wee hours on Monday. Some locals, however, have alleged that the incident was the result of a quarrel between Binod and Babu in drunken condition. Binod was injured when he was pushed and he fell down on a tin plate.” We have arrested Babu on the basis of a complaint lodged by the victim’s wife. We are questioning the locals for further leads,” a senior police official said.
Kalimpong: 311 persons residing in forest villages and Khasmahal area of Kalimpong district received land right documents (Pattas) from the state government on Thursday. This is the first time that land right documents are being distributed in the Hills. Chief Minister Mamata Banerjee, during her visit to Kalimpong, had announced on Tuesday that land documents will be given to the landless under the Nijo Bhumi Nijo Griho scheme of the state government. Also Read – Heavy rain hits traffic, flightsAroop Biswas, minister in-charge of Public Works, Youth Services and Sports department, handed over the land right documents at Hanuman Jhora on National Highway 10, around 30 km from Kalimpong.”There are many leaders in the country who have only given speeches. There is only one leader in India who lives up to her commitment. She is Mamata Banerjee. She had committed to upgrade Kalimpong into a full-fledged district, peace and development in the Hills, a new university and an education hub. She has lived up to all her commitments,” stated the minister. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedHe stated that Mamata Banerjee is ready to lay down her life, if required for the Hills. “For peace and development in the Hills, our leader Mamata Banerjee is ready to take any step. Our job is to work together to bring her dreams to life,” stated Biswas.He stated that many political parties have come to the Hills, including many MPs, who had promised many things but can be seen nowhere now. “They had given hundreds of assurances but not a single one has been translated into reality. Our Chief Minister has already identified 4 stress areas, including drinking water, sewage, solid waste management and roads. She has directed the state government, municipalities, GTA and development boards to work together, to resolve all issues in these areas in the next two years. Let us all work together,” Biswas said. Though 311 beneficiaries were handed over the land documents, there were assurances to complete the handing over of the documents to all eligible persons in the Hills within the end of this year.”CM Mamata Banerjee has asked me to convey this message. She has assured that handing over of land right documents to all eligible persons in Darjeeling and Kalimpong will be completed by the end of this year,” stated GTA chief Binay Tamang.Tamang asked the Hills to abstain from politicising everything and instead work for the benefit of the masses. “There are many, who mislead people for their own vested interests. Everything should not be politicised. This is the main reason why the Hills are backward. Let us all rise above petty politics for the betterment of the Hills,” said Tamang.There was an air of jubilation as the long standing demand of the masses was transformed into reality. “We had been living in a plot for generations but used to face severe problems as we did not have land documents. Mamata Banerjee has given us the best gift. We have our own address now,” stated Babita Rai of Riyang Forest Village.
Exposure to lead during the development stages and early childhood is likely to increase the risk of obesity in adulthood, finds a new research. The results of the study conducted on mice found that exposure to lead during early development stages of life can change the gut microbiota — a complex community of micro-organisms that live in the digestive tracts of animals — in a way that it significantly raises the chances of obesity in adulthood.“Early life exposure to lead causes a long lasting impact on gut microbiome, and the change of gut microbiome may partially contribute to the increased body weight in adult life,” said lead author Chuanwu Xi, associate professor at the University of Michigan in US. Also Read – ‘Playing Jojo was emotionally exhausting’Adult male mice exposed to lead during the gestation period and infancy stages were 11 per cent larger than those not exposed. Mice exposed to lead during early development stages showed differences in their gut microbiota and had fewer aerobes and more anaerobes in their gut.In both males and females, developmental lead impacted the adult microbiome, the researchers maintained, adding that the study only observed adult onset obesity in the males. Also Read – Leslie doing new comedy special with NetflixLead was added to the drinking water of mice mother prior to breeding through nursing their young. The lead levels were carefully designed to be within human population exposure levels.Once weaned, the offspring were raised to adulthood without additional exposure, and then tested for lead effects acquired from their mothers, the researchers explained in the study published in the journal Toxicological Sciences.Lead is found throughout the environment in natural and man-made settings. For decades, researchers have found many health problems associated with exposure, even at levels lower than the threshold for safety set by the US Centers for Disease Control and Prevention (CDC).In the study, the researchers used deep DNA sequencing of bacterial specific genes to examine the guts of both males and females.
Mothers with a history of depression are not physiologically “in sync” with their children and this may lead to conflicts in their relations, a study has found.The findings indicate that children and the mothers who were sad during the interaction were more likely to be “out of sync” with one another.While interacting, sometimes one just feels like they’re in sync with somebody and they know that the interaction is going really well and they’re enjoying the conversation. “We’re trying to figure out, at the body level, in terms of your physiology, do you see this synchrony in moms and their kids and then how is that impacted by depression?” said Brandon Gibb from Binghamton University in the US. The study, published in the Journal of Child Psychology and Psychiatry, measured heart rate variability — a physiological measure of social engagement — in children aged 7-11 and their mothers (44 with a history of depression and 50 with no such history) while they engaged in positive and negative discussions. In the first discussion, mother-child pairs planned a dream vacation together and in the second, they addressed a recent topic of conflict between them — homework, using the TV or computer, being on time, problems at school and lying, etc.The results indicate that mothers with no history of depression displayed physiological synchrony — similar increases or decreases in heart rate variability — with their children during negative discussion.“We found that mothers who had no history of depression were really matching their children’s physiology in the moment,” said lead study author Mary Woody. “In mothers with a history of depression, we’re seeing the opposite. They actually mismatched. As one person is getting more engaged, the other person is pulling away. So they were walking away from the discussion feeling sad,” Woody added.The synchrony during interactions is disrupted at the physiological level in families with a history of maternal depression and may be a potential risk factor for the inter-generational transmission of depression, the authors suggested.