Health

Pain relief: When to use cold, when to use heat

(HealthDay)—Sore from a workout? You don't have to reach for pain relief medicine when ice or heat will help. But when should you go cold and when should you go warm?

Neuroscience

How can ultrasonic brain stimulation cure brain diseases?

Just as rays of sunlight can be focused by a magnifying glass, beams of ultrasound can be focused—not to start a fire, but to converge on a specific target. The pulses of ultrasound are able to pass through obstructions ...

Parkinson's & Movement disorders

Genetic markers linked to the start of symptoms of Parkinson's disease

Researchers from the Institute of Neurosciences of the University of Barcelona (UBNeuro), Hospital Clínic and the August Pi i Sunyer Biomedical Research Institute (IDIBAPS) have identified a group of genetic variants related ...

Radiology & Imaging

Magnetic eyelashes: A new source of MRI artifacts

A new cosmetic product, magnetic eyelashes, should be of interest and concern to radiology professionals working in the MRI environment, according to an ahead-of-print article published in the November 2019 issue of the American ...

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Plastic

Plastic is the general common term for a wide range of synthetic or semisynthetic organic amorphous solid materials suitable for the manufacture of industrial products. Plastics are typically polymers of high molecular weight, and may contain other substances to improve performance and/or reduce costs.

The word derives from the Greek πλαστικός (plastikos) meaning fit for molding, and πλαστός (plastos) meaning molded. It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into an enormous variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.

The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminum, for instance, is plastic in this sense, but not a plastic in the common sense; while some plastics, in their finished forms, will break before deforming and therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosets. Thermoplastics, if exposed to enough heat, will melt. Thermosets will keep their shape until they are charred and burnt. Some examples of thermoplastics are grocery bags, piano keys and some automobile parts. Examples of thermosets are children's dinner sets and circuit boards.

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