Materials informatics reveals new class of super-hard alloys

A new method of discovering materials using data analytics and electron microscopy has found a new class of extremely hard alloys. Such materials could potentially withstand severe impact from projectiles, thereby providing ...

No assumptions needed to simulate petroleum reservoirs

Hidden deep below our feet, petroleum reservoirs are made up of hydrocarbons like oil and natural gas, stored within porous rock. These systems are particularly interesting to physicists, as they clearly show how temperature ...

Pressure makes best cooling

Phase transitions take place as heat (i.e., entropy) is exchanged between materials and the environment. When such processes are driven by pressure, the induced cooling effect is called the barocaloric effect, which is a ...

Noble metal-free catalyst system as active as platinum

Industry uses platinum alloys as catalysts for oxygen reduction, essential in fuel cells and metal-air batteries, among other applications. Expensive and rare, that metal imposes tight restrictions on manufacture. Researchers ...

Entropy and search engines

Entropy, a term loosely referring to the disorder of a physical system and infamously associated with the Second Law of Thermodynamics, wherein we know that it ultimately increases in any closed system, might be used to gauge ...

Disorder can stabilize batteries

Novel materials can considerably improve storage capacity and cycling stability of rechargeable batteries. Among these materials are high-entropy oxides (HEO), whose stability results from a disordered distribution of the ...

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Entropy

Entropy is a concept applied across physics, information theory, mathematics and other branches of science and engineering. The following definition is shared across all these fields:

where S is the conventional symbol for entropy. The sum runs over all microstates consistent with the given macrostate and is the probability of the ith microstate. The constant of proportionality k depends on what units are chosen to measure S. When SI units are chosen, we have k = kB = Boltzmann's constant = 1.38066×10−23 J K−1. If units of bits are chosen, then k = 1/ln(2) so that .

Entropy is central to the second law of thermodynamics. The second law in conjunction with the fundamental thermodynamic relation places limits on a system's ability to do useful work.

The second law can also be used to predict whether a physical process will proceed spontaneously. Spontaneous changes in isolated systems occur with an increase in entropy.

The word "entropy" is derived from the Greek εντροπία "a turning towards" (εν- "in" + τροπή "a turning").

This text uses material from Wikipedia, licensed under CC BY-SA