Stochastic processes are ubiquitous in nature. Also known as random processes, they can take multiple forms like a random walk, or a game of chance. Their studies have played a pivotal role in the development of modern physics starting with Langevin and the Brownian motion well illustrated by pollen grain floating in water. Recent advances in measurement precision and resolution have extended the framework of Brownian motion to unprecedented space-time scales and to a wider variety of systems, including atomic diffusion in optical lattices and spin diffusion in liquids. Studies of such systems are providing insights into the mechanisms and interactions responsible for stochasticity.
For example, membrane fluctuations are also a purview of Brownian motion. Where it becomes really interesting is when properly understood, the random membrane fluctuations can be usefully exploited for energy harvesting. From a stochastic...
Finding a new energy storage material is a great challenge and sodium is showing great promise. Being one of the two main ingredients in the salt, it is very abundant, non-toxic and cheap. However, it is very difficult to produce a sodium based battery. The problem is, when exposed to air, the metals in a sodium battery’s cathode can be oxidized, decreasing the performance of the battery or even rendering it completely inactive.
In the last years, research on the development of sodium-ion batteries have been making great progress in terms of performance utilizing layered transition-metal oxides and polyanions. It appears that the sodium compounds can be promising compared with their lithium analogs. Combining, the layered metal oxides with polyanions will offer a good compromise between high energy densities and stable cycle life.
The EM drive – a radio frequency (RF) resonant cavity thruster – appears to produce an ‘impossible’ thrust. Impossible – in that it apparently violates Newtons third law of motion: “For every action, there is an equal and opposite reaction.” Now in a recent paper by a group of Portuguese physicists, led by Prof. Jose Croca from the Center for Philosophy of Sciences at the University of Lisbon, present a possible explanation for this observed ‘impossible’ thrust.
The EM drive was first proposed in 2001 by British inventor Roger Sawyer and has subsequently been tested by numerous groups around the world alongside possible explanations for its propulsion. However, still a hot topic of debate, a consensus on the level of thrust and an explanation for the thrust has not been found.
Croca and his team hope to change this through their explanation...
Recently, electromagnetic radiation in the terahertz (THz) frequency range has emerged as one of the most promising imaging techniques for a variety of applications in science and engineering. The potential and suitability of the THz technology for practical applications such as the nondestructive testing field has been released by the recent progress in producing efficient sources and detectors. Thanks to the development of ultra-fast components in both photonics and electronics, the situation is evolving rapidly.
THz waves, residing at a relatively unexplored region between the microwave and infrared, roughly 0.1-10THz, is one of the last frontiers in the electromagnetic spectrum. Unlike X-ray, THz is a non-ionizing radiation. It causes no known harm to the human body and the materials being examined. Moreover, THz can penetrate many common gases, non-polar liquids, and...
Metamaterials are a class of super-materials with remarkable characteristics. Metamaterials have been engineered to bend and shape light, providing an effective invisibility cloak.
The EmDrive, originally developed by Roger Shawyer at SPR Ltd., is a propellant-free microwave thruster that produces acceleration via an electromagnetic cavity without need for traditional fuel sources. After several successful experimental demonstrations of the EmDrive’s ability to produce thrust by NASA’s Eagleworks laboratory, several researchers are using the quantum mechanical model of Pilot Wave theory to describe how the engine interacts with the quantum vacuum to produce thrust.