“Because the posture response of the bicycle is passive, it is not possible to control directly,” Murakami explained. “Therefore, it is necessary to do the stabilization control indirectly by using the bicycle steering control. This is one reason why bicycle stabilization becomes difficult.”While the optimal stabilization strategy allowed the bicycle to run on a straight path on the rollers, the other strategies could stabilize the bike’s posture, but had position errors that resulted in the bicycle diverging from its straight path. One key to achieving these results was developing a simplified dynamic model for a bicycle, a modification of the more complicated but widely studied Sharp dynamic model developed by R. S. Sharp in 1971. The researchers’ simplified version enabled them to develop a bicycle controller that fused stability and trajectory control. While these experiments tested the bicycle’s ability to ride in a straight line, the researchers predict that the control strategy could also extend to curved trajectories. The team plans to make improvements to the model to account for road irregularities and tire characteristics, which weren’t accounted for in this study. By confirming the feasibility of bicycle stability unassisted by a human rider, the researchers hope to continue making bicycles increasingly sophisticated and safe.“Our final goal is to stabilize the bicycle at zero speed,” Murakami said. “Many bicycle falling accidents happen when elderly people stop a bicycle in a crosswalk, and so on.”More information: Tanaka, Yasuhito, and Murakami, Toshiyuki. “A Study on Straight Line Tracking and Posture Control in Electric Bicycle.” IEEE Transaction on Industrial Electronics. To be published.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 This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. 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. Despite the challenge, engineers from Keio University in Yokohama, Japan, are developing a self-stabilizing electric bicycle, one that can stay upright by itself while being propelled and steered by electric motors. Their ultimate goal is to create a sophisticated, high-performance bicycle that could serve as a convenient alternative to a small car.Yasuhito Tanaka and Toshiyuki Murakami, both with the Department of System Design Engineering at Keio University, will publish their study in an upcoming issue of IEEE Transactions on Industrial Electronics.“The bicycle is a comfortable vehicle that is safe and can offer more familiarity with nature compared with the car,” Murakami told PhysOrg.com. “Especially, the bicycle is a convenient vehicle that can be useful as an activity for elderly people. However, it is thought that a lot of bicycle falling accidents occur with elderly people, and it is very useful to achieve a safer bicycle.”As the first step toward their goal, the researchers designed an electric bicycle that maintains its balance and follows a straight path. In simulations and experiments, they tested three different strategies that combine stability control and trajectory control. The researchers found that a combination of the “posture controller” (for stability) and “steering function controller” (for trajectory) could enable the bicycle to drive by itself continuously. In the experimental set-up, a conventional bicycle was placed on three rollers – two underneath the rear wheel and one underneath the front wheel. When the rear rollers rotated, the front roller rotated through a wire. Two motors controlled the motion of the bicycle – the motor on the handlebars controlled steering, and the motor in the back drove the rear wheel at an average speed of 2.5 meters per second. To monitor the bicycle’s position and stability, the engineers attached an LED to the back side of the bicycle, and used a camera mounted behind the bike to monitor the LED’s movement. A gyro sensor attached to the bicycle also detected changes in the bicycle’s direction angle. The researchers could control the bicycle in real time using feedback from these sensors with an RTLinux operating system. As the researchers explained, adjustments to the acceleration (back motor) and steering (front motor) were straightforward because the feedback could be interpreted to have a clear physical meaning. The control system then calculated the necessary motor adjustments. In the experimental set-up, the bicycle ran on rollers. The motor on the handlebars controlled steering, while the motor in the back drove the rear wheel. The gyro sensor, LED, and camera detected the bicycle’s position, which gave feedback to a control system that adjusted the motors to maintain bicycle stabilization. Image credit: Yasuhito Tanaka and Toshiyuki Murakami. ©2008 IEEE. Explore further Citation: Engineers design self-stabilizing electric bicycle (2008, November 4) retrieved 18 August 2019 from https://phys.org/news/2008-11-self-stabilizing-electric-bicycle.html Shared e-cargo bikes: Boom and barriers in Basel (PhysOrg.com) — As every five-year-old knows, balancing on a bicycle is not as easy as it looks. But, as engineers know, getting a bicycle to balance by itself – without a human riding it – is even more difficult.
Explore further Citation: Physicists Propose New Ultracold Scheme for Scalable Quantum Information Processing (2009, June 3) retrieved 18 August 2019 from https://phys.org/news/2009-06-physicists-ultracold-scheme-scalable-quantum.html Physicists Kathy-Anne Brickman Soderberg, Nathan Gemelke, and Cheng Chin of the University of Chicago have presented their novel system in a recent issue of the New Journal of Physics. As the scientists explain, the scheme uses two different species of atoms: lithium atoms act as quantum bits to store information, and cesium atoms act as messenger bits that mediate entanglement between distant lithium qubit atoms. Each atomic species is trapped in its own optical lattice, which is an intensity pattern made by several overlapping laser beams. By shifting the relative alignment of the lattices through optical phases, each cesium atom can, in principle, be transported to any distant lithium atom in a controlled way. During this shifting, the cesium atoms can swap entanglement between any two lithium qubit atoms. In the end, the qubit atoms are entangled with each other and the messenger atom is disentangled from the qubits.While previous schemes have also used atoms in optical lattices to implement entanglement, the new proposal is unique in that it introduces the auxiliary messenger atoms. As the scientists explain, independent control of the qubit and messenger atoms provides the key to achieve a large-scale quantum computation. The fact that lithium and cesium atoms have very different dominant atomic transition lines makes it possible to independently confine and control the two species. Atoms trapped in optical lattices have several advantages as a quantum information processing system. As the physicists explain, this kind of system easily lends itself to scalability because thousands of atoms can be isolated in a regular array, and can be transported simply by controlling the optical phases of the lattice beams. Also, since many cesium atoms can be held in the optical lattice, multiple copies of the same computation can proceed in parallel.“Our scheme is scalable in the sense that we do not need to carry out pairwise operations over the lattice to entangle two distant qubits,” Brickman Soderberg told PhysOrg.com. “Instead we can use the messenger atoms to directly carry the entanglement between the qubits. Another strength of our system is that we can individually address our qubit atoms by overlapping the target qubit with a messenger atom, thus eliminating the need for tightly focused laser beams. This will allow us to perform targeted single qubit operations, which may be a necessary step in a large-scale quantum computer.”
Explore further The company released the following statement about the creation of the prototype screen:“Our company makes digital signage, and people were asking us to create a large screen device which has multi-touch functionality like a smart phone. We first tried to make it using Windows 7, but it didn’t meet the needs of our customers. They said they wanted crisp, fluid movement like in a smart phone but with a high-resolution display. But when we asked touch panel and peripheral manufacturers they said they don’t support the Android OS, so we were temporarily stalled. We want to do a lot more work with Android in the future, so we decided to develop the system ourselves.”This means that the company also had to develop their own drivers for the device in order to have a multi-touch display of this size run properly. Of course, this screen will not only come in the 32″ prototype size. When the screens are sold commercially the company expects to sell in a variety of sized, including a 23″ and a 46″. There is also some discussion about the creation of a wide screen version of this device.The product is expected to be ready for commercialization by September, though no release specifics have been given at this time. © 2010 PhysOrg.com (PhysOrg.com) — Researchers at SKR have developed a prototype of a multi-touch 32″ display screen that runs on the Android operating system. The screen, which runs off of a standard Android terminal, is connected to the touch sensors and an HDMI screen via a USB port. The end result of the screen is that the android interface works like smaller devices, but it can also display large format Full HD video. 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 keyboard software makes typing faster on touch screens (w/ Video) Citation: SKR researchers develop a 32-inch Android-based multi-touch display (2011, July 6) retrieved 18 August 2019 from https://phys.org/news/2011-07-skr-inch-android-based-multi-touch.html
Explore further Crude oil no longer needed for plastics (PhysOrg.com) — As most people know, modern plastics are made from crude oil derivatives, making them vulnerable to price and supply fluctuations, which in the end means an alternative must be found in order for the plastics industry to remain viable. One alternative is to use plant material, or biomass instead. Unfortunately, at least till now, the lack of a good catalyst has made the process both expensive and messy, at least for those that create plastics that are virtually identical to the ones based on petroleum. Now, researchers in The Netherlands have found an iron catalyst that appears to be both effective and doesn’t produce a messy byproduct. They describe their work in the journal Science. Citation: Research team develops better iron catalyst to help turn plant material into plastic (2012, February 17) retrieved 18 August 2019 from https://phys.org/news/2012-02-team-iron-catalyst-material-plastic.html More information: Supported Iron Nanoparticles as Catalysts for Sustainable Production of Lower Olefins, Science, 17 February 2012: Vol. 335 no. 6070 pp. 835-838. DOI: 10.1126/science.1215614ABSTRACTLower olefins are key building blocks for the manufacture of plastics, cosmetics, and drugs. Traditionally, olefins with two to four carbons are produced by steam cracking of crude oil–derived naphtha, but there is a pressing need for alternative feedstocks and processes in view of supply limitations and of environmental issues. Although the Fischer-Tropsch synthesis has long offered a means to convert coal, biomass, and natural gas into hydrocarbon derivatives through the intermediacy of synthesis gas (a mixture of molecular hydrogen and carbon monoxide), selectivity toward lower olefins tends to be low. We report on the conversion of synthesis gas to C2 through C4 olefins with selectivity up to 60 weight percent, using catalysts that constitute iron nanoparticles (promoted by sulfur plus sodium) homogeneously dispersed on weakly interactive α-alumina or carbon nanofiber supports. © 2011 PhysOrg.com Journal information: Science Biomass can be used to make plastics by burning it which produces a mix of carbon monoxide and hydrogen. When a catalyst is added to the mix, (most of which are generally based on iron) syngas is produced with olefins in it. The olefins are the components in syngas that form into plastic when they are chemically connected together. The problem up till now has been that the catalysts used thus far haven’t been very efficient (the proportion of olefins in the syngas were very small) and tended to produce carbon dust and methane.In this new research, the team studied many different iron based materials hoping to find one that would work better. After an exhaustive search they discovered that by changing the grain size of one such catalyst material from an average of 500 nanometers to just 20, and then forcing the grains to be evenly spaced apart to prevent clustering, improved efficiency dramatically. Then, by accident (one of their chemicals had been accidently tainted) they found that adding a tiny bit of sulfur and sodium to the mix improved the efficiency even more. The end result is a process so efficient that no carbon dust or methane is produced.The researchers acknowledge that the process still isn’t efficient enough to compete with those based on petroleum products, despite the fact that it produced roughly fifty percent more lower olefins than previous methods. At just 60% efficiency, that still leaves 40% waste, too much for it to be considered a viable replacement, at least at current oil prices and availability. More optimistically, the fact that the team was able to double the efficiency of current methods suggests that even better efficiencies in the future might be found. 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.
© 2013 Phys.org Explore further The announcement comes on the heels of news from Mars One—the Netherlands based group selling tickets for a one way trip to the red planet—announcing that over 78,000 people have signed up so far. Some of those people might change their mind however when they learn of recent discoveries about the content of Martian dust.NASA’s chief health and medical officer, Richard Williams, told those at the summit that perchlorates appear to be widespread on the planet’s surface. The fine dust material produced by perchloric acid has been known to cause thyroid problems in people here on Earth. Just as problematic, Grant Anderson (co-founder of Paragon Space Development) told the audience, is gypsum. The Curiosity rover has found veins of it near the planet’s surface. Though it’s not toxic, it has been known to cause a condition similar to black lung in coal miners in people exposed to it for long periods of time.Both types of dust particles are in addition to the known presence of silicates on the Martian surface—if breathed-in they can cause reactions with water in the lungs and result in the creation of harmful chemicals.Martian dust could pose health hazards because of the difficulty of removing it from space suits and boots. NASA learned during the Apollo space missions that moon dust was a much bigger problem than had been anticipated. They have reported in the past on the large amounts of dust that stuck to astronaut suits and boots. Fine grains stick to materials because of static electricity, and on Mars would likely be sucked into a controlled environment by an air-lock. Over time, health specialists fear the dust would build up in air filters and living quarters, adding yet another life threatening element to the list of other known hazards (traveling and landing safely, exposure to radiation and cosmic rays, etc.) for the people who seek to colonize the planet.Space technologists have yet to figure out a way to remove the fine particulates from suits and boots and because of that, manned missions to Mars could be put on hold indefinitely. NASA scientists eyeing regional dust storm on Mars (Phys.org) —Reports given by experts in the space-health field suggest it might take longer for humans to build a colony on Mars than has been expected. Such experts speaking to attendees at the recent “Humans 2 Mars Summit” in Washington D.C. expressed concern about the dangers of Martian dust. They believe the health hazards posed by the Martian regolith could prevent humans from colonizing the planet anytime soon. More information: via Newscientist Citation: Reports from “Humans 2 Mars Summit” suggest dust may prevent human settlement of Mars (2013, May 10) retrieved 18 August 2019 from https://phys.org/news/2013-05-humans-mars-summit-human-settlement.html Mars surface. 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.
Researchers build reversible tractor beam that moves objects 100 times farther than other efforts PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Play Light propagation in air. Credit: Nature Communications 6, Article number: 6021 doi:10.1038/ncomms7021 Though it is not clear just yet if the technique will have any real applications (such as watching plasma develop as ions are heated), the team appears satisfied with their work noting that they were able to achieve their goal. Play Formation and evolution of laser-induced plasma. Credit: Nature Communications 6, Article number: 6021 doi:10.1038/ncomms7021 Citation: Research group figures out a way to film a laser in normal air bouncing off mirrors (w/ Video) (2015, January 29) retrieved 18 August 2019 from https://phys.org/news/2015-01-group-figures-laser-air-mirrors.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.
Citation: Cat shelter findings: Less stress with box access (2015, February 8) retrieved 18 August 2019 from https://phys.org/news/2015-02-cat-stress-access.html © 2015 Phys.org 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. Journal information: Applied Animal Behaviour Science More information: Applied Animal Behaviour Science, www.appliedanimalbehaviour.com … 0236-6/abstract?cc=y Out of all those cat videos that keep your eyes glued to the screen far longer than you would care to acknowledge, you may have seen some showing little and big cats trying their best to snuggle into big and too-little cardboard boxes. What makes them so content about being in a box? Scientists have spent much time looking for answers. “Will a hiding box provide stress reduction for shelter cats?” That is one such exploration, published in Applied Animal Behaviour Science, the journal of the International Society for Applied Ethology (ISAE). The three authors, from the Faculty of Veterinary Medicine, University of Utrecht, studied stress in shelter cats and found that hiding boxes reduced stress, at least on the short term. They chose shelters as their investigation site because that is where the stress levels for domestic cats can be serious. The researchers assessed the effect of a hiding box on stress levels of newly arrived cats in a Dutch animal shelter. Ten cats had a box; nine did not. They found a significant difference between the two groups on observation days 3 and 4. The cats with the hiding box were able to recover faster in their new environment.Writing in Wired, Bryan Gardiner took up the topic of why cats love boxes, discussing the researchers’ findings as well as other explorations into the way cats love scampering and even squeezing into boxes. One of the authors of the Dutch cat shelter paper, Claudia Vinke, was quoted in Wired: “Hiding is a behavioral strategy of the species to cope with environmental changes and stressors,” Vinke said in her email. Cornell University’s College of Veterinary Medicine, in their observations about cat shelters and stress, said that “cats benefit greatly from the ability to hide when stressed. In shelters, this can be accomplished in a variety of ways, with a range of costs and benefits.” One type of hiding spot which they recommended was a “hiding box” which they said could be “a cardboard box, a specially designed Hide-Perch-and-Go box, a sturdier plastic box or cage insert, a plastic carrier, or a commercially available “cat den.” The Cornell site said that while cardboard boxes are inexpensive, they cannot be cleaned, and must only be used for one cat before being discarded or recycled. Gardiner in Wired made the point that boxes are not the only enclosures that attract cats; bowls, a bathroom sink, or other enclosures seem to work, too. Gardiner also made the point that cats scramble for such enclosures in a fundamental search not merely to feel psychologically cozy but for heat.”According to a 2006 study by the National Research Council, the thermoneutral zone for a domestic cat is 86 to 97 degrees Fahrenheit. That’s the range of temperatures in which cats are ‘comfortable’ and don’t have to generate extra heat to keep warm or expend metabolic energy on cooling.” Corrugated cardboard, he added, is a good insulator; if the box is a tight squeeze so much the better; it may “force the cat to ball up or form some other impossible object, which in turn helps it to preserve body heat.” A cat’s game of hide and seek