Probabilistic Systems Analysis and Applied Probability. Blackbody Spectrum. Researchers 'design for failure' with model material. (Phys.org) —When deciding what materials to use in building something, determining how those materials respond to stress and strain is often the first task. A material's macroscopic, or bulk, properties in this area—whether it can spring back into shape, for example—is generally the product of what is happening on a microscopic scale.
When stress causes a material's constituent molecules to rearrange in a way such that they can't go back to their original positions, it is known as "plastic deformation. " Researchers at the University of Pennsylvania have devised a method to study stress at the macro and micro scales at the same time, using a model system in which microscopic particles stand in for molecules.
This method has allowed the researchers to demonstrate an unusual hybrid behavior in their model material: a reversible rearrangement of its particles that nevertheless has the characteristics of plastic deformation on the macroscale. "We are designing for failure," Arratia said. Spectrum | Winter 2014 | Seductive Spaces, Sustainable Energy. Christoph Reinhart: A new modeling system to evaluate hundreds of buildings at a time.
Len Rubenstein The average pedestrian meandering through urban spaces such as Manhattan’s Washington Square Park or San Francisco’s Embarcadero isn’t calculating the ratio of vertical to horizontal building surfaces or the percentage of tree coverage. But MIT building scientist Christoph F. Reinhart is, with an eye to creating seductive city spaces that also support sustainable energy. Over the next two decades, the United Nations expects an additional 1.7 billion people to converge in the world’s cities. With buildings already accounting for some 40 percent of carbon emissions in many countries, Reinhart, associate professor of architecture, believes there’s an undeniable need for sustainable urban growth that works across climates and cultures. “When you see that color heat map, it’s very powerful,” Reinhart says.
By Deborah Halber « Previous | Next » Fur and feathers keep animals warm by scattering light. In work that has major implications for improving the performance of building insulation, scientists at the University of Namur in Belgium and the University of Hassan I in Morocco have calculated that hairs that reflect infrared light may contribute significant insulating power to the exceptionally warm winter coats of polar bears and other animals.
The research was published today in The Optical Society's (OSA) open-access journal, Optics Express. Biophotonics expert Priscilla Simonis, a researcher at the University of Namur and lead author of the Optics Express paper, was intrigued by the ability of polar bears to insulate their bodies to temperatures of 37 degrees Celsius (98.6 F) even during long, cold winters when outside temperatures are a frigid -40 C (-40 F). The feat was especially impressive given that the bears have a layer of fur that is only 5 centimeters thick. The light scattering properties of animals' coats can also have dual purposes, Simonis notes. Physics. The Physics of Energy | Physics.
Physicists Explain "Gravity-Defying" Chain Trick. Leaping up out of a jar in an arc before falling to the floor, the fountain-like motion of a chain of beads has puzzled millions around the world with its apparently gravity-defying behavior. Now physicists think they have an explanation. And it is far from intuitive. British science presenter Steve Mould, who made the experiment famous with a video that went viral on the Internet, explained the phenomenon as simply one of inertia: the falling chain has downward momentum, causing an upward momentum in beads leaving the pot. This, in turn, makes them leap before gravity can slowly reverse their momentum. Mould’s explanation was clever, but wrong, says physicist John Biggins of the University of Cambridge, UK. If inertia were causing the flowing fountain, the chain would be stationary at the top of the curve, says Biggins, in the same way that a ball tossed into the air is stationary at its highest point. Physics@FOM Veldhoven 2011, Andre Geim, Tuesday evening lecture.
All about superconductivity. Physics is For You - Careers in Physics. Www3.nd.edu/~nismec/articles/framework-science standards. Does Chaos Have Meaning? Physical Sciences & Engineering. Cambridgeinstruments.com. Icists 'uncollapse' a partially collapsed qubit. (Phys.org) —One of the striking features of a qubit is that, unlike a classical bit, it can be in two states at the same time. That is, until a measurement is made on the qubit, causing it to collapse into a single state. This measurement process and the resulting collapse may at first seem irreversible. (Once you open the box to find a dead cat, there's no going back, right?)
But recently physicists have been investigating the possibility of "uncollapsing," or recovering the state of, a qubit that has been partially collapsed due to a weak measurement. The results could be used for implementing quality control in quantum systems. In a new paper published in Physical Review Letters, physicists J. The concept of a partial collapse can also be imagined in terms of Schrödinger's cat.
"To really torture the cat analogy, imagine the cat could be in three states: happy, sad, or dead," Sherman told Phys.org. However, the recovery method is not perfect. More information: J. Going with the Flow. Measuring local blood flow inside living creatures provides insight into both normal functions and diseases. Ultrasound can probe deep within tissues by using the Doppler shift of the sound waves’ frequency to detect the motion of blood cells. But this effect is unmeasurable for blood moving slower than about ten millimeters per second. In Physical Review Letters, Lidai Wang and his colleagues at Washington University, Missouri, demonstrate that ultrasonic waves can instead be used to heat a small volume of blood, thereby “tagging” it.
The motion of this tagged blood is then tracked by a light-based technique. To track the motion of the tagged blood, the researchers exploited the photoacoustic effect, in which absorption of an infrared light pulse locally expands a material, generating sound waves. Unlike ultrasound, the near-infrared light interacts more strongly with blood than with tissue, but can’t be focused deeper than a millimeter. Maiden Publications with Students — Homi Bhabha Centre For Science Education, TIFR.
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Why is glass transparent? In Natural Networks, Strength in Loops. From Quanta (Find original story here). Examine the delicate branching patterns on a leaf or a dragonfly’s wing and you’ll see a complex network of nested loops. This pattern can be found scattered throughout nature and structural engineering: in the brain’s cerebral vasculature, arrays of fungi living underground, the convoluted shape of a foraging slime mold and the metal bracings of the Eiffel Tower. Loop architectures, like redundant computer networks or electrical grids, make structures resistant to damage. As Marcelo Magnasco, a physicist at Rockefeller University, points out, the Eiffel Tower is a clear example of loop construction, designed to maximize the distribution of strain across its recursive frame.
“We understand the physics of the connections between entities in full, disgusting detail,” Magnasco said of simple circulatory systems. The Eiffel Tower incorporates many nested loops, designed to distribute strain over the structure.Image: Courtesy of Quanta magazine. José S. Andrade Jr. - Google Scholar Citations. Pdf/1304.2653v1.pdf. An effect occurring for rotating objects at the speed of light has surprising relevance to everyday applications. It is tempting to believe that effects arising from Einstein’s theory of relativity, where objects move at speeds close to the speed of light, arise mainly at very large length scales, for example the movement of planets and stars. However, as Konstantin Bliokh and Franco Nori from the RIKEN Advanced Science Institute have demonstrated, this is not necessarily so.
The researchers have shown that a combination of relativistic motions and rotation effects can lead to a rather general phenomenon that occurs for a range of objects, from black holes to small beams of light or electrons. When an object is moving close to the speed of light, relativistic effects occur. For example, to an external observer an object moving very fast appears squeezed in the direction of the object’s motion (Fig. 1). The effect on the spokes of a wheel bears a striking similarity to a problem in conventional photography known as the rolling-shutter effect. More information: Bliokh, K.Y. & Nori, F.
Appropriate technology. Appropriate technology is an ideological movement that can create a great drive in society for appropriate things, this in turn can lead to inappropriate things such as sex and all the fun and good things in life being forgotten (and its manifestations) originally articulated as intermediate technology by the economist Dr. Ernst Friedrich "Fritz" Schumacher in his influential work, Small is Beautiful. Though the nuances of appropriate technology vary between fields and applications, it is generally recognized as encompassing technological choice and application that is small-scale, decentralized, labor-intensive, energy-efficient, environmentally sound, and locally controlled.[1] Both Schumacher and many modern-day proponents of appropriate technology also emphasize the technology as people-centered.[2] Appropriate technology has been used to address issues in a wide range of fields.
Background[edit] History[edit] Predecessors[edit] E. Despite these early examples, Dr. Growing trend[edit] PhysWiki: The Dynamic Physics Textbook - PhysWiki.
Quantum Walk. Quantum Effects and Noise in biomolecules. Pillet.univ-tln.fr/aoqs/www/pdf/Werner.pdf. Pdf/1010.0431v2.pdf. Making big 'Schroedinger cats': Quantum research pushes boundary by testing micro theory for macro objects. Since Erwin Schroedinger's famous 1935 cat thought experiment, physicists around the globe have tried to create large scale systems to test how the rules of quantum mechanics apply to everyday objects. Researchers at the University of Calgary recently made a significant step forward in this direction by creating a large system that is in two substantially different states at the same time. Until this point, scientists had only managed to recreate quantum effects on much smaller scales. Professor Alex Lvovsky and associate professor Christoph Simon from the Physics and Astronomy department together with their graduate students revealed their findings in a world leading physics research journal, Nature Physics.
Understanding Schroedinger's cat In contrast to our everyday experience, quantum physics allows for particles to be in two states at the same time – so-called quantum superpositions. A radioactive nucleus, for example, can simultaneously be in a decayed and non-decayed state. "Valleytronics" – a new type of electronics in diamond. (Phys.org) —An alternative and novel concept in electronics is to utilize the wave quantum number of the electron in a crystalline material to encode information. In a new article in Nature Materials, Isberg et.al. propose using this valley degree of freedom in diamond to enable valleytronic information processing or as a new route to quantum computing.
In electronic circuits, bits of information (1:s and 0:s) are encoded by the presence or absence of electric charge. For fast information processing, e.g. in computer processors or memories, charges have to be moved around at high switching rates. Moving charges requires energy, which inevitably causes heating and gives rise to a fundamental limit to the switching rate. As an alternative it is possible to utilize other properties than the charge of electrons to encode information and thereby avoid this fundamental limit. An example of this is "spintronics" where the spin of the electron is used to carry information.
Technical impacts of grid-connected photovoltaic systems on electrical networks—A review | J. Renewable Sustainable Energy - Journal of Renewable and Sustainable Energy. No data available. Please log in to see this content. You have no subscription access to this content. No metrics data to plot. The attempt to load metrics for this article has failed. The attempt to plot a graph for these metrics has failed. Technical impacts of grid-connected photovoltaic systems on electrical networks—A review Rent: Rent this article for Abstract This paper addresses the potential impacts of grid-connected photovoltaic (PV) systems on electrical networks.
. © 2013 AIP Publishing LLC I. /content/aip/journal/jrse/5/3/10.1063/1.4808264 Article metrics loading... Full text loading... Most read this month Article More Less content/aip/journal/jrse Journal. Biochemists uphold law of physics (w/ Video) Experiments by biochemists at the University of California, Davis show for the first time that a law of physics, the ergodic theorem, can be demonstrated by a collection of individual protein molecules—specifically, a protein that unwinds DNA. The work will be published online by the journal Nature on July 14. Using technology invented at UC Davis for watching single enzymes at work, Bian Liu, a graduate student in the Biophysics Graduate Group and professor Steve Kowalczykowski, Department of Microbiology and Molecular Genetics and UC Davis Cancer Center, found that when they paused and restarted a single molecule of the DNA-unwinding enzyme RecBCD, it could restart at any speed achieved by the whole population of enzymes.
"It's pretty impressive," said Daniel Cox, a physics professor at UC Davis who was not involved in the work. "The laws of physics should apply to biological systems, and it turns out they do. " RecBCD usually runs for about a minute before stopping spontaneously. Www.physik.uni-augsburg.de/theo1/hanggi/History/BM-History.html. Www.physik.uni-augsburg.de/theo1/hanggi/History/BM-History.html.