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Glossary

Vadose, saturated, unsaturated zone
The vadose zone (also called unsatured) is the subsurface zone above the water table and the capillary fringe in which pores within the geologic matrix are partially filled with air and partially filled with water, and fluid pressure is less than atmospheric. The satured zone is the subsurface zone below the water table where pores within the geologic matrix are filled with water and fluid pressure is greater than atmospheric.

Variety index
A measure of the variety of living things in a community, based upon one of several mathematical formulae which account for both numbers of species and numbers of individuals within species. High diversity results from high numbers of species and an even distribution of numbers within species. Stressed environments generally have low diversity.

Vegetable kingdom
It refers to organisms belonging to the kingdom Plantae. These organism have the following general characteristics: lack of locomotion, lack of a nervous system, cellulose cell walls. Most organisms can photosynthesize. There are more than 250,000 species within the kingdom.

Vent
A component of a heating or ventilation appliance used to conduct fresh air into, or waste air or combustion gases out of an appliance or interior space.

Vertebrate
Term used to define an animal with a backbone. Subphylum Vertebrata is the largest group of Chordates including fishes, amphibians, reptiles, and mammals.

Vibration
Mechanical oscillation or motion about a reference point of equilibrium.

Vibroseis
The process of producing seismic shock waves with “thumpers” or vibrator vehicles.

Visbreaking
A typical refinery process used to obtain low viscosity and pour-point products from a plant feedstock generally made up of crude distillation residuals.

Volcano
A vent in the surface of the Earth through which magma and associated gases and ash erupt; also, the form or structure (usually conical) that is produced by the ejected material.A volcano is “active” when it is erupting or has erupted recently. Volcanoes that have not erupted recently but are considered likely to erupt in the future are said to be “dormant.” A volcano that has not erupted for a long time and is not expected to erupt in the future is “extinct”.

 

 

 

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