NYPD Goes Green

first_img 40 hybrid patrol cars obviously are not enough to cover all of New York City. However, the city has analyzed the precincts that are most likely to benefit from the hybrid police cars. These precincts include those with large areas of coverage, as well as precincts that may be smaller but sport a great deal of stop and go traffic. The idea is to maximize the benefit of the cars by putting them in areas where the positive environmental gains — and the economic profit — are most evident.The City of New York actually has 3,300 hybrids in service (out of 26,000), but they are mostly assigned to departments that do not see a lot of public safety action: parks and rec, buildings and sanitation. The NYPD will be monitoring these patrol cars to make sure that they are safe and efficient. Hopes are that more hybrid patrol vehicles can be added in the future, helping the NYPD save money on gas. The cost of an Altima, at $25,391, is only a little more than the Crown Victoria ($24,875) and the Chevy Impala ($23,967) also used. As a result, it should be possible for the gas savings from the Altima to more than make up the difference.Also interesting: The Nissan Altima Hybrids are actually made in the U.S.A. The Crown Victorias and Imapalas? Made in Canada.More information: Red, Green and Blue.© 2009 PhysOrg.com Hybrid police cars for the NYPD. Explore further (PhysOrg.com) — New York City has a goal to reduce its overall carbon footprint. For Manhattan, the goal is to reduce greenhouse gases 30% by 2017. As part of this effort, the New York City Police Department just added 40 hybrid cars to its fleet. The Nissan Altima Hybrids are the first NYPD alternative fuel patrol cars, but they probably won’t be the last. The NYPD plans to deploy at least 100 hybrids in total this year. Stop or I’ll download Citation: NYPD Goes Green (2009, May 5) retrieved 18 August 2019 from https://phys.org/news/2009-05-nypd-green.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

California may use vibrational energy of driving to generate power

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Researchers uncover aerodynamics of the best attributes of the common jump rope

center_img (PhysOrg.com) — One of the cool things about science is, no matter where you are, it’s all around you, and sometimes all that’s needed is for someone to open their eyes to something that has always just been there. Take jumping rope for example. Jeffrey Aristoff and Howard Stone found themselves wondering one day if the mechanics of the whole operation had ever been studied and worked out. What went on with the rope and what traits made for faster or slower jumping, for example. Last year the two set up a robotic jump rope and filmed the whole process and found that in spite of how things might look to the naked eye, the rope bends out of the plane. Now, a year later, the two have done some more research on the subject and have published their results in Proceedings of the Royal Society A. 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. © 2011 PhysOrg.comlast_img read more

Research duo discover why nonNewtonian fluids harden on impact

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Graphene coating transforms fragile aerogels into superelastic materials

first_img Journal information: Nature Nanotechnology More information: Kyu Hun Kim, et al. “Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue.” Nature Nanotechnology. Advance Online Publication. DOI: 10.1038/NNANO.2012.118 As compression increases in this sequence of images, the graphene-coated nanotubes undergo increasing alignment, strengthening the aerogel. Image credit: Kim, et al. ©2012 Macmillan Publishers Limited To overcome this inelasticity problem, the researchers demonstrated that one to five layers of graphene coating enables a CNT aerogel to withstand more than 1 million compressive cycles and return to its original shape after compression release. The ability to withstand this compression turns the aerogels into superelastic materials, while at the same time allowing them to maintain their other properties such as porosity and conductivity.The researchers think that the graphene coating imparts this superelasticity to the aerogel by strengthening the aerogel’s nodes and struts, both of which support the aerogel’s network structure. In non-coated aerogels, the struts can bend and freely rotate about the nodes when compressed, which increases the contact area between nanotubes and forms new nodes. When the load is removed, the new nodes remain since more force is required to remove the nodes than to form them. Citation: Graphene coating transforms fragile aerogels into superelastic materials (2012, August 9) retrieved 18 August 2019 from https://phys.org/news/2012-08-graphene-coating-fragile-aerogels-superelastic.html In contrast, the stronger struts in graphene-coated aerogels cannot easily rotate about the nodes when compressed. Although new nodes are formed in the coated aerogels as well, the graphene coating can remove these nodes when the load is removed.“Both CNT aerogels and graphene-coated CNT aerogels form ‘new’ nodes when compressed,” Islam explained. “We think that the graphene at the nodes gets compressed and crumpled when the graphene-coated aerogels are compressed. When the load is removed, nanotube aerogels do not recover original shape because there is no restorative force to ‘break’ the new nodes that formed during compression. In contrast, the compressed and crumpled graphene flakes provide the restorative force (i.e., act as springs) that is needed to break these new nodes in graphene-coated aerogels.”CNT aerogels that can undergo high levels of compression and later spring back to their original shapes could open the doors to new aerogel applications. CNT aerogels already have attractive features, such as the inherent flexibility of aerogel synthesis that allows researchers to control their shapes and sizes, and superelasticity makes these materials even more attractive.“CNT aerogels, particularly single-walled carbon nanotube (SWCNT) aerogels, have a high surface area, are electrically conducting, have large pores, and have fairly good thermal dissipation properties if you consider that the amount of material in them is really small,” Islam said, adding that his team has recently published papers on the aerogels’ heat transport properties and a surface area close to the theoretical limit. “Because of their properties, CNT aerogels can be used as a scaffold to make composites, sieves, ultralight heat sinks in high gravity applications, electrodes, and catalyst supports. Typically, nanotubes are incompatible with polymers and tend to phase-segregate. By using aerogels as a scaffold and backfilling with polymer, nanotubes can remain well-dispersed in the polymer matrix. This can significantly improve mechanical enhancement.”The researchers are currently investigating other areas of CNT aerogels, in addition to superelasticity.“We are currently working on a few projects,” he said. “We are using SWCNT aerogels to make electrically conducting composites. We are also looking into making mechanically strong polymer composites. With our collaborators, we are exploring the electrochemical properties of SWCNT aerogels. We are growing metal nanoparticles on these SWCNT aerogels for use as filters for remediation of harmful chemicals from water. Also we are using them as porous 3D conducting substrates for tissue growth.“I think the modulus and strength of these nanotube aerogels need to be improved without decreasing the porosity. As you can imagine, the aerogels can be made significantly stronger by just increasing the volume fraction of nanotubes in them but this will reduce the porosity.” Explore further Copyright 2012 Phys.org 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. Penn Physicists Develop a Carbon Nanotube Aeroegel Optimizing Strength, Shape and Conductivity After CNT aerogels are compressed and released, the non-coated aerogel collapses while the graphene-coated aerogel recovers its original shape. Image credit: Kim, et al. ©2012 Macmillan Publishers Limited The researchers, Kyu Hun Kim, Youngseok Oh, and Mohammad F. Islam at Carnegie Mellon University in Pittsburgh, Pennsylvania, have published their paper on the mechanical benefits of a graphene coating on CNT aerogels in a recent issue of Nature Nanotechnology.”We demonstrate the transformation of a nanotube network from fragile to superelastic simply via ‘nanocoating,’” Islam told Phys.org. “Typically, coating adds corrosion resistance, lubrication, aesthetics, alteration of surface chemistry, sealing, etc., but not mechanical property change.”While a normal gel consists mostly of liquid material with a cross-linked network that gives it its solid-like structure, an aerogel is created by replacing the liquid material in a gel with a gas. Researchers do this by drying the original gel at a critical temperature. The resulting aerogel is a lightweight material made of 99.9% air by volume, yet one that is also dry, rigid, and strong like a solid.In the current study, the researchers worked with CNT aerogels, which (in addition to the air) are made of dispersed nanotubes about 1 micrometer long. CNT aerogels hold their shape due to molecular interactions at the nodes, the points where the nanotubes cross each other. However, when these aerogels are compressed by up to 90% of their original size, they collapse or become permanently deformed, limiting potential applications. (Phys.org) — Like donning a Superman’s cape, fragile carbon nanotube (CNT) aerogels that are covered by a graphene coating can be transformed from a material that easily collapses under compression to one that can resist large amounts of compression and completely recover its original shape after removal of the load. The superelasticity and fatigue resistance provided by the graphene coating could make CNT aerogels useful in a variety of areas, including as electrodes, artificial muscles, and other mechanical structures. 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

Manipulating Lorentz and Fano spectral line shapes

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Flexible allcarbon electronics integrated onto plants insects and more

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New fossils show ancient comb jellies had skeleton parts

first_imgFour taxa of Cambrian skeletonized comb jellies. Credit: Dr. Qiang Ou and his colleagues Contrary to popular belief, though they may look a lot like them, comb jellies are not jellyfish, instead they belong to the phylum Ctenophora. Scientists have found over a hundred species of the creature in its modern form and not one of them has any sort of skeleton. That is why the find in China is so surprising, an early relative that lived approximately 520 million years ago (during the Cambrian Period), did have some bony parts.The fossils were found at the famous Chengjiang site, embedded in rock—in all, six species were found among over three dozen specimens, each with some amount of hard skeleton material. The bone-like material was shaped like spokes, struts or plates. The plates appeared to cover the bodies, serving apparently, as a barrier against predators, or perhaps some other harmful environmental factor. The researchers cannot say for sure what the bone-like material was made of but suspect it was likely chitin or something similar, or even a carbonate rich mineral material. Also, because of the arrangement of the spokes or struts, the team suggests that the bones could have served a dual purpose, structural support and as a defense mechanism. In a bit of a twist, if the skeletal parts were indeed meant as a protection mechanisms, it does not appear to have worked out—the fossil species found in the rocks never made it to the modern age, they all died out.The finding also appears to contradict theories (based on DNA models) that have suggested ancient comb jellies had tentacles—none of the fossils had any sign of them. On the other hand, finding they had skeletons suggests they faced unknown threats, which should present a new avenue for study. © 2015 Phys.org More information: A vanished history of skeletonization in Cambrian comb jellies, Science Advances  10 Jul 2015: Vol. 1, no. 6, e1500092. DOI: 10.1126/sciadv.1500092AbstractCtenophores are traditionally regarded as “lower” metazoans, sharing with cnidarians a diploblastic grade of organization. Unlike cnidarians, where skeletonization (biomineralization and sclerotization) evolved repeatedly among ecologically important taxa (for example, scleractinians and octocorals), living ctenophores are characteristically soft-bodied animals. We report six sclerotized and armored ctenophores from the early Cambrian period. They have diagnostic ctenophore features (for example, an octamerous symmetry, oral-aboral axis, aboral sense organ, and octaradially arranged ctene rows). Unlike most modern counterparts, however, they lack tentacles, have a sclerotized framework, and have eight pairs of ctene rows. They are resolved as a monophyletic group (Scleroctenophora new class) within the ctenophores. This clade reveals a cryptic history and sheds new light on the early evolution of this basal animal phylum. Skeletonization also occurs in some other Cambrian animal groups whose extant members are exclusively soft-bodied, suggesting the ecological importance of skeletonization in the Cambrian explosion. Explore further (Phys.org)—A team of researchers with members from several institutions in China and one in the U.S. has found evidence that shows that ancient comb jellies had skeleton parts. In their paper published in the journal Science Advances, the team describes comb jelly ancestor fossils that were found in rock formations in China, the skeleton parts they found and theories regarding possible reasons for those parts.center_img Ancient balloon-shaped animal fossil sheds light on Earth’s ancient seas Citation: New fossils show ancient comb jellies had skeleton parts (2015, July 13) retrieved 18 August 2019 from https://phys.org/news/2015-07-fossils-ancient-jellies-skeleton.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. Journal information: Science Advanceslast_img read more

Underground formations reveal wet past of Australias Nullarbor Plain

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Model suggests 1812 San Andreas earthquake may have been set off by

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