Environmental Engineering Reference
In-Depth Information
Viewshed:
The scenic characteristics of an area, when referred to as a resource.
Visible light transmittance:
The amount of visible light that passes through the
glazing material of a window, expressed as a percentage.
Volt age:
The measure of electrical potential difference.
W
Watt, electric:
The electrical unit of power; the rate of energy transfer equivalent
to 1 ampere of electric current flowing under a pressure of 1 volt at unity
power factor.
Watt-hour (Wh):
The electrical energy unit of measure equal to 1 watt of power
supplied to, or taken from, an electric circuit steadily for 1 hour.
Watt, thermal:
A unit of power in the metric system, expressed in terms of energy
per second; equal to the work done at a rate of 1 joule per second.
Well log:
Includes measurements of the diameter of the well and various electrical,
mass, and nuclear properties of the rock which can be correlated with physi-
cal properties of the rock. The well log is a chart of measurements relative
to depth in the well.
Wind energy:
Energy present in wind motion that can be converted to mechani-
cal energy for driving pumps, mills, and electric power generators. Wind
pushes against sails, vanes, or blades radiating from a central rotating shaft.
Wind power plant:
A group of wind turbines interconnected to a common utility
system through a system of transformers, distribution lines, and (usually)
one substation. Operation, control, and maintenance functions are often
centralized through a network of computer monitoring systems, supple-
mented by visual inspection. This is a term commonly used in the United
States; in Europe, it is called a
generating station
.
Wind rose:
A diagram that indicates the average percentage of time that the wind
blows from different directions on a monthly or annual basis.
Wind turbine or windmill:
A device for harnessing the kinetic energy of the wind
and using it to do work, or generate electricity.
Wind vane:
Wind direction measurement device, used to send data to the yaw drive.
Wind-wave direction (WWD):
The direction that the wind waves are coming
from. Wind waves are produced by the local wind. If a swell is present,
these waves arrive at a lower period (more frequently) than do the swells.
Direction is given on a 16-point compass scale.
Wind-wave height (WWH):
The average height of the highest one-third of the wind
waves. It is estimated by the process mentioned under “Swell height,” except
that it is calculated from the energies above the separation frequency.
Wind-wave period (WWP):
The peak period in seconds of the wind waves.
Windward:
Into or facing the direction of the wind; opposite of leeward.
Wood energy:
Wood and wood products used as fuel, including roundwood (cord-
wood), limb wood, wood chips, bark, sawdust, forest residues, charcoal,
pulp waste, and spent pulping liquor.
Wood pellets:
Sawdust compressed into uniform-diameter pellets to be burned in a
heating stove.
