Definitions - v

Ventilation

The supply and introduction of adequate air for ventilation and control of airborne contaminants, acceptable temperatures and relative humidity.

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Vermicomposting

The process where worms feed slowly on decomposing materials (e.g. vegetable scraps) in a controlled environment to produce nutrient-rich soil.

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Vertical Axis Wind Turbine

A wind generator design where the rotating shaft is perpendicular to the ground, and the cups or blades rotate parallel to the ground.

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Vertical-axis Wind Turbine

A wind turbine with the axis or main shaft mounted vertically, or perpendicular to the earth's surface. This type of turbine does not need to be turned to face the wind - the wind always blows across it. Types include Savonius and Darrius.

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Vicariance

The evolution of a new species from a group separated from the original species by a geographic barrier.

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Virga

Rain which fall in the sky but evaporates before it reaches the ground.

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Virgin Materials

Resources extracted from nature in their raw form, such as timber or metal ore.

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Virgin Paper

Virgin paper is paper that contains no recycled content and is made directly from the pulp of trees or, alternatively, cotton.

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Volatile Organic Compounds

A hydrocarbon deposit, such as petroleum, coal, or natural gas, derived from living matter of a previous geologic time and used for fuel.

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Voltage Drop

The voltage lost along a length of wire or a conductor due to the internal resistance of that conductor. The voltage drop is calculated using Ohms Law. 

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