Hydrogen peroxide is described as a valuable non-irritating and non-poisonous antiseptic. It effervesces in the presence of pus due to the liberation of oxygen. Usual strength 10 volumes, i.e. it contains ten times its volume of available oxygen.

Heat pump (as used in geothermal industry) in which the refrigerant exchanges heat in a heat exchanger with a fluid circulating through an earth connection medium - ground or ground water. The fluid is contained in a variety of loop/pipes configurations depending on the temperature of the ground and the ground area available. Loops may be installed horizontally or vertically in the ground or submersed in a body of water.

Hand control is described as a mechanical system that allows for operation of both the gas and brake pedals by either hand and is accomplished by means of a combination lever mounted to the steering column.

Hairspring is defined ad a fine spiral spring that regulates the movement of the balance wheel in a timepiece. Also known as balance spring, this is the small spiral spring that is attached to the balance wheel, the quality of which can affect the regularity and accuracy of a movement.

Horizontal classification means a grouping of species from a similar time interval of evolution rather than those sharing a common lineage (horizontal with respect to a phylogenetic tree). Compare --->'vertical classification'.

Handheld vacuum is a machine which is portable and sometimes cordless which make them ideal for cleaning small areas like the car. In addition to upright vacuums, it is good to use handheld vacuums because they can clean areas which an upright can not clean because they are too large.

Ref: 124164/2006-09-21

Hair-curlers and curling irons are heating devices designed to curl human hair. Both hair curlers and curling irons contain heating elements controlled by a thermostat. In addition, a thermal cutoff or fuse prevents appliance burnouts due to overheating.

The term hydrate may refer to the following:

  • to cause a person or object to absorb water or other liquid
  • a chemical substance containing water or its constituent elements

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