Nano- and Microtechnology from A - Z: From Nanosystems to Colloids and Interfaces

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Janus Particles

Particles having two sides with differing surface properties, one usually being polar and the other nonpolar. They are named for the ancient god Janus, who had two faces. An interfacial film of Janus particles has some spaces between the particle grains and therefore such a film is permeable. One method of preparing colloidal-sized Janus particles involves creating an oil-in-water Pickering emulsion using paraffin wax as the oil [177]. See also Reference [178].

Jar Test

For emulsions, foams, or water treatment, see Bottle Test.

Jensch Head

(Microscopy) See Microscope Head.

Jet Impactor

See Impactor.

Jet Impingement

A dispersion technique in which a jet of liquid is directed at a surface or at a jet of another liquid.

Jet Insecticide

See Aerosol Spray.

Jet Mill

A machine for the comminution, or size reduction, of mineral or other particles. Such machines accelerate feed particles in a jet and cause size reduction by promoting interparticle and particle–wall collisions at high speed. Very small-sized particles can be produced with these mills. Also termed jet pulverizers.

Jet Pulverizer

See Jet Mill.

Jones–Ray Effect

The decrease in apparent surface tension of water, as determined by capillary rise, due to the addition of small amounts of electrolyte. In reality, the surface tension of water increases.

Joule, James Prescott (1818–1889)

A British natural philosopher who made contributions in the areas of heat and thermodynamics. His work led ...