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Editorial Briefing
Cooling paint

Oct 2018

Cooling paint

In the journal Science (September 2018), researchers reported a method for making a coating that reflects sunlight and radiates heat. The coating can be used to cool buildings and reduce air-conditioning use, keeping surfaces painted with the material about 6 degrees Celsius cooler than the surrounding air temperature. The paint can be easily applied to most surfaces, including the exterior walls and roofs of existing buildings. The cooling effect is based on a phenomenon known as passive daytime radiative cooling, whereby a surface cools without any energy input by reflecting ultraviolet to near-infrared solar radiation (278- to 4600-nanometer wavelengths) and radiating long-wave radiation (8000- to 13,000-nanometer wavelengths) through the atmosphere to outer space. Cool roofs designed using metals (such as aluminum) or white-pigmented paints help keep building temperatures lower by reflecting sunlight but are less effective at emitting the heat they absorb because heat is reflected inside these materials. See also: Buildings; Emissivity; Heat transfer; Infrared radiation; Paint and coatings; Radiation; Reflection of electromagnetic radiation; Solar radiation

Editorial Briefing
Harnessing the power of nuclear fusion in tokamak reactors

Feb 2019

Harnessing the power of nuclear fusion in tokamak reactors

Progress continues in the attempt to master nuclear fusion—the phenomenon that powers the stars, including our Sun—for energy production here on Earth. Recent research has identified a previously unknown kind of heat burst that causes reaction-killing instabilities inside experimental fusion machines, called tokamaks. These doughnut-shaped vessels contain and sustain the controlled fusion reaction, using magnetic fields to trap and guide superheated hydrogen. On Earth, nuclear fusion requires heating hydrogen up to approximately 100 million Kelvin (100 million degrees Celsius or 180 million degrees Fahrenheit), thus converting it into a state of matter called plasma. Within this superheated plasma, atoms can start to fuse together into heavier atoms, releasing energy in the process. See also: Atom; Atomic nucleus; Atomic physics; Earth; Electricity; Energy; Energy sources; Gas; Hydrogen; Magnetic confinement fusion; Matter (physics); Nuclear fusion; Nuclear physics; Nuclear reaction; Plasma (physics); Star; Sun; Temperature; Thermonuclear reaction

Editorial Briefing
New findings on how hydrogen gas burns

Jun 2020

New findings on how hydrogen gas burns

A new study has shown that dangerous hydrogen-burning flames can persist in unexpectedly narrow spaces and with very low fuel volumes. The findings highlight potential challenges involved in the safe storage and transport of hydrogen gas, which holds promise as a zero-emissions, alternative fuel source for vehicles. To date, only a few hydrogen fuel cell–powered automobiles are available in select markets. Given the substantial contribution of fossil fuel burning (including gasoline) to global climate change, however, there is substantial interest in further developing such vehicles for mass-market use. See also: Alternative fuels for vehicles; Fossil fuel; Fuel cell; Gasoline; Global climate change; Hydrogen

Editorial Briefing
Probing fireballs with lasers to better understand explosions

Sep 2019

Probing fireballs with lasers to better understand explosions

An exploding fireball is a difficult phenomenon to examine given its fleeting, rapidly evolving, and hazardous nature. A specific type of laser is now offering researchers a new way to study explosions, though, at safe distances and with the attendant sensitivity needed to capture sudden changes in temperature, pressure, and chemical concentrations. The hope is that probing explosions in this manner will aid in better controlling them for technological applications, as well as designing protective shielding from explosives. See also: Explosive; Explosive forming; Laser; Pressure; Temperature; Thermodynamic principles

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