hydraulic motor |
By altering the internal osmotic pressure within a cell, water will enter and a considerable expansion of the compartment will occur. This has been used as a motor device in plants (turgor pressure), in eversion of nematocysts and possibly in the production of other cellular protrusions. (18 Nov 1997) |
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hydraulics |
That branch of science, or of engineering, which treats of fluids in motion, especially of water, its action in rivers and canals, the works and machinery for conducting or raising it, its use as a prime mover, and the like. As a science, hydraulics includes hydrodynamics, or the principles of mechanics applicable to the motion of water; as a branch of engineering, it consists in the practical application of the mechanics of fluids to the control and management of water with reference to the wants of man, including canals, waterworks, hydraulic machines, pumps, water wheels, etc. Some writers treat hydraulics and hydrostatics as subdivisions of hydrodynamics. Origin: Cf. F. Hydraulique. Source: Websters Dictionary (01 Mar 1998) |
hydrazide |
An organic compound of the general formula RCO-NHNH2; an acyl derivative of hydrazine. (05 Mar 2000) |
hydrazine |
<chemistry> Any one of a series of nitrogenous bases, resembling the amines and produced by the reduction of certain nitroso and diazo compounds; as, methyl hydrazine, phenyl hydrazine, etc. They are derivatives of hydrazine proper, H2N.NH2, which is a doubled amido group, recently (1887) isolated as a stable, colourless gas, with a peculiar, irritating odour. As a base it forms distinct salts. Synonym: diamide, amidogen, (or more properly diamidogen), etc. Origin: Hydr- + azo- + -ine. Source: Websters Dictionary (01 Mar 1998) |
hydrazine yellow |
<chemistry> An artificial dyestuff obtained as an orange-yellow powder, and regarded as a phenyl hydrazine derivative of tartaric and sulphonic acids. Origin: Tartaric + hydrazine. Source: Websters Dictionary (01 Mar 1998) |
hydrazinolysis |
Cleavage of chemical bonds by hydrazine (NH2-NH2); applied in protein and nucleic acid degradations. (05 Mar 2000) |
hydrazone |
A substance derived from aldehydes and ketones by reaction with hydrazine or a hydrazine derivative to give the grouping ==C==N-NH2. (05 Mar 2000) |
hydrazones |
Compounds of the general formula r:n.nr2, as resulting from the action of hydrazines with aldehydes or ketones. (12 Dec 1998) |