Engineering

Food safety: Cleaning with plasma instead of chemicals

A new method for cleaning conveyor belts in food production can replace the widely used disinfection chemicals. Plasma-treated water is effective against microbial contamination at a shorter exposure time and degrades without ...

Engineering

Novel solar desalination system for remote areas developed

With summer temperatures soaring, the specter of water scarcity looms large. As a possible solution to increase the availability of clean, potable water, researchers at the Indian Institute of Science (IISc) have developed ...

Energy & Green Tech

An electric vehicle battery for all seasons

Many owners of electric vehicles worry about how effective their battery will be in very cold weather. Now a new battery chemistry may have solved that problem.

Electronics & Semiconductors

Researchers enhance conversion efficiency of thermoelectric devices

In the effort to reduce our reliance on fossil fuels, one strategy involves harvesting the waste heat that is already being produced by our energy systems. Thermoelectric generators can convert waste heat to clean electricity, ...

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Temperature

In physics, temperature is a physical property of a system that underlies the common notions of hot and cold; something that feels hotter generally has the higher temperature. Temperature is one of the principal parameters of thermodynamics. If no heat flow occurs between two objects, the objects have the same temperature; otherwise heat flows from the hotter object to the colder object. This is the content of the zeroth law of thermodynamics. On the microscopic scale, temperature can be defined as the average energy in each degree of freedom in the particles in a system. Because temperature is a statistical property, a system must contain a few particles for the question as to its temperature to make any sense. For a solid, this energy is found in the vibrations of its atoms about their equilibrium positions. In an ideal monatomic gas, energy is found in the translational motions of the particles; with molecular gases, vibrational and rotational motions also provide thermodynamic degrees of freedom.

Temperature is measured with thermometers that may be calibrated to a variety of temperature scales. In most of the world (except for Belize, Myanmar, Liberia and the United States), the Celsius scale is used for most temperature measuring purposes. The entire scientific world (these countries included) measures temperature using the Celsius scale and thermodynamic temperature using the Kelvin scale, which is just the Celsius scale shifted downwards so that 0 K= −273.15 °C, or absolute zero. Many engineering fields in the U.S., notably high-tech and US federal specifications (civil and military), also use the kelvin and degrees Celsius scales. Other engineering fields in the U.S. also rely upon the Rankine scale (a shifted Fahrenheit scale) when working in thermodynamic-related disciplines such as combustion.

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