For tiny fractions of a second, when illuminated by a laser pulse, quartz glass can take on metallic properties. The phenomenon, recently revealed by large-scale computer simulations, frees electrons, allowing quartz to become opaque and conduct electricity. The effect could be used to build logical switches which are much faster than today’s microelectronics.
Researchers from North Carolina State Univ. have developed a novel and versatile modeling strategy to simulate polyelectrolyte systems. The model has applications for creating new materials as well as for studying polyelectrolytes, including DNA and RNA. Polyelectrolytes are chains of molecules that are positively or negatively charged when placed in water.
New supercomputing calculations provide the first evidence that particles predicted by the theory of quark-gluon interactions but never before observed are being produced in heavy-ion collisions at the Relativistic Heavy Ion Collider, a facility that is dedicated to studying nuclear physics. These heavy strange baryons, containing at least one strange quark, still cannot be observed directly.
Nature’s artistic and engineering skills are evident in proteins. Scientists at Rice Univ. have now employed their unique theories to show how the interplay between evolution and physics developed these skills. The team used computer models to show that the energy landscapes that describe how nature selects viable protein sequences over evolutionary timescales employ the same forces as those that allow proteins to fold.
A team of economists including Esteban Rossi-Hansberg of Princeton University's Woodrow Wilson School of Public and International Affairs have developed a model that can measure the widespread effects of local industry fluctuations such as sudden closing of a major airline hub. Gauging the power of these fluctuations, or shocks, could be a useful tool when it comes to designing policies to manage past and future shocks.
By now, most scientists agree that the temperature of the planet is rising and that the increase is due to human activities. But the jury still out regarding the variability of that increase. Researchers using “big data” computational tools have recently taken a systematic approach to answering this question and their results point to both higher global temperatures and increasing variability among those temperature extremes.
Until now, computer simulations of habitable climates on Earth-like planets have focused on their atmospheres. Mathematicians and earth sciences experts in the U.K. have recently taken the next step, creating a computer-simulated pattern of ocean circulation on a hypothetical ocean-covered Earth-like planet. They hope to learn how different planetary rotation rates would impact heat transport with the presence of oceans taken into account.
Biological physicists at Rice Univ. have succeeded in analyzing transmembrane protein folding in the same way they study the proteins’ free-floating, globular cousins. They have applied energy landscape theory to proteins that are hard to view because they are inside cell membranes. The method should increase the technique’s value to researchers who study proteins implicated in diseases and possibly in the creation of drugs to treat them.
A decade of research by Rice Univ. scientists has produced a 2-D model to prove how gas hydrate, the “ice that burns,” is formed under the ocean floor. Gas hydrate has potential as a source of abundant energy, if it can be extracted and turned into usable form. It also has potential to do great harm.
Iron is present in tiny concentrations in seawater, on the order of a few billionths of a gram in a liter. However, its availability in seawater can have a profound effect on phytoplankton growth and, consequently, the Earth's carbon cycle. In recent research, an assessment was made of the various sources of dissolved iron in the north Atlantic Ocean and surprising discoveries were made about their origins.
According to a team of researchers who applied a statistical technique to conventional, coarse-scale climate models, population centers in cool, highland regions of East Africa could be more vulnerable to malaria than previously thought, while population centers in hot, lowland areas could be less vulnerable. The new approach improves the accuracy of earlier efforts that used global climate model simulations results.
Fully automated "deep learning" by computers greatly improves the odds of discovering particles such as the Higgs boson, according to a recent study. In fact, this approach beats even veteran physicists' abilities, which now consists of developing mathematical formulas by hand to apply to data. New machine learning methods are rendering that approach unnecessary.
The light-warping structures known as metamaterials have a new trick in their ever-expanding repertoire. Researchers at NIST have built a silver, glass and chromium nanostructure that can all but stop visible light cold in one direction while giving it a pass in the other. The device could someday play a role in optical information processing and in novel biosensing devices.
Using the quantitative approach of physicists, biologists in Israel have developed experimental tools to measure precisely the bacterial response to antibiotics. Their mathematical model of the process has led them to hypothesize that a daily three-hour dose would enable the bacteria to predict delivery of the drug, and go dormant for that period in order to survive.
Aerospace engineers from the Univ. of Illinois, Urbana-Champaign are using the National Science Foundation-supported Stampede supercomputer to explore how jets in general, like those on modern aircraft and inside the human body, generate noise. This is important because no simple explanation of how jets generate noise is currently available, and without this understanding making jets quieter is difficult.
Concentrating solar power (CSP) could supply a large fraction of the power supply in a decarbonized energy system, according to a new study of the technology and its potential practical application. For this research, scientists simulated the construction and operation of CSP systems in four regions around the world, taking into account weather variations, plant locations, electricity demand, and costs.
Organic semiconductors have tremendous potential for complementing conventional, inorganic semiconductors, but energy losses or barriers at the connection interfaces have blocked development efforts. Physicists have now implemented a detailed electrostatic model which is capable of covering the full phenomenological range of interfacial energy-level alignment regimes within a single, consistent framework.
Seemingly ordinary, water has quite puzzling behavior. Why, for example, does ice float when most liquids crystallize into dense solids that sink? Using a computer model to explore water as it freezes, a team at Princeton Univ. has found that water's weird behaviors may arise from a sort of split personality: At very cold temperatures and above a certain pressure, water may spontaneously split into two liquid forms.
It’s likely that most of the large impact craters on Earth have already been discovered and that others have been erased, according to a new calculation by a pair of Purdue Univ. graduate students. Although it's known that natural processes erase craters fairly quickly from the Earth's surface, this model was the first to quantify how many craters have likely been erased.
Inspired by anomalies that arise in certain mathematical equations, researchers have demonstrated a laser system that paradoxically turns off when more power is added rather than becoming continuously brighter. The finding could lead to new ways to manipulate the interaction of electronics and light, an important tool in modern communications networks and high-speed information processing.
A new study of supermassive black holes at the centers of galaxies has found magnetic fields play an impressive role in the systems’ dynamics. In fact, in dozens of black holes surveyed, the magnetic field strength matched the force produced by the black holes’ powerful gravitational pull, says a team of scientists.
Imagine a tower that builds itself into the desired structure only by choosing the appropriate bricks. Absurd, but in the nano world self-assembly is now a common practice for forming structures. Researchers in Austria have been investigating how they can control the ordering of self-assembling structures and discovered how to switch the assembly process on and off.
Bacteria use threadlike appendages, called pili, to creep along a surface, and some disease-causing microbes extend pili in all directions to move. But until now researchers have been unable to explain why bacteria like these are able to travel in a straight line consistently. A new model developed to describe this movement shows that bacteria do not act as randomly as they appear to when moving.
According to new research from Sweden, two aircraft engine concepts, a geared turbofan and an open rotor, can enable a significant reduction to aircraft fuel consumption. With an open rotor, the potential reduction is 15%. An open rotor engine generates most of the thrust from two counter-rotating propellers instead of a ducted fan. This enables a larger engine diameter and a higher propulsive efficiency.
In a typical wind farm, the wind turbine located in the wakes of upstream turbines would experience a much different surface wind compared to the ones located upwind due to wake interferences. Scientists at Iowa State Univ. have completed a study on the effects of these relative rotation directions, using two tandem wind turbines as a model. They found a big difference in performance between co-rotating and counter-rotating turbines.