Energy terms starting with V

70 terms

vacuum distillation The separation of two or more liquids under reduced vapor pressure; reduces the boiling points of the liquids being separated.
Vacuum Evaporation The deposition of thin films of semiconductor material by the evaporation of elemental sources in a vacuum.
Valence Band The highest energy band in a semiconductor that can be filled with electrons.
Valley floor The gently sloping to nearly level bottom surface of a valley.
Valley segment That portion of a stream network with similar morphologies and governing geomorphic processes identified by valley bottom and sideslope geomorphic…
Vapor Retarder A material that retards the movement of water vapor through a building element (walls, ceilings) and prevents insulation and structural wood from becoming…
Variable-Speed Wind Turbines Turbines in which the rotor speed increases and decreases with changing wind speed, producing electricity with a variable frequency.
Variance A special exemption of a zoning law to allow the property to be used in a manner different from an existing law.
Vehicle Categories A system of classifying vehicles (e.g., passenger cars, commercial vehicles, trailers, off-road vehicles, and special-purpose vehicles).
Vehicle Weight Class The size of vehicles. Includes light-duty, medium-duty, and heavy-duty vehicles based on their gross vehicle weight rating (the weight of a vehicle on its…
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.
Vent Damper A device mounted in the vent connector that closes the vent when the heating unit is not firing.
Vent Pipe A tube in which combustion gases from a combustion appliance are vented out of the appliance to the outdoors.
Vented Heater A type of combustion heating appliance in which the combustion gases are vented to the outside, either with a fan (forced) or by natural convection.
Ventilation The process of moving air (changing) into and out of an interior space either by natural or mechanically induced (forced) means.
Ventilation Air That portion of supply air that is drawn from outside, plus any recirculated air that has been treated to maintain a desired air quality.
Vernal pool Seasonally-flooded depressions found on soils with an impermeable layer such as a hardpan, claypan, or volcanic basalt.
Vertebrate Any species having a backbone or spinal column including fish, amphibians, reptiles, birds, and mammals.
Vertical angle of view Elevation of viewer relative to the elevation of the proposed action, and the resulting angle of difference.
Vertical Ground Loop In this type of closed-loop geothermal heat pump installation, the fluid-filled plastic heat exchanger pipes are laid out in a plane perpendicular to the…
Vertical-Axis Wind Turbine (VAWT) A type of wind turbine in which the axis of rotation is perpendicular to the wind stream and the ground.
View duration Length of time a proposed action is in view. Impacts that are viewed for a long period of time are generally judged to be more severe than those viewed…
Viewer distance The distance from a viewpoint to a seen object or landscape element.
Viewpoint A point from which a landscape view is analyzed and/or evaluated.
Viewshed The total landscape seen or potentially seen from all or a logical part of a travel route, use area, or water body.
Virtual bidding In two-settlement electricity markets, financial transactions that allow participants to hedge against the risk that real-time and day-ahead prices will…
Visibility factors Conditions or other phenomena that affect the visibility or appearance of an object or a landscape.
Visible Light Transmittance The amount of visible light that passes through the glazing material of a window, expressed as a percentage.
Visible Radiation The visible portion of the electromagnetic spectrum with wavelengths from 0.4 to 0.76 microns
Visual absorption capability The physical capacity of a landscape to accept human alterations without loss of its inherent visual character or scenic quality.
Visual attention Noticing and focusing of vision on a particular object or landscape element.
Visual clutter The complex visual interplay of numerous disharmonious landscape characteristics and features resulting in a displeasing view.
Visual contrast Opposition or unlikeness of different forms, lines, colors, or textures in a landscape.
Visual disharmony A state of disagreement, incongruity, or disproportionate arrangement of forms, lines, colors, and textures in the visual elements of a seen landscape.
Visual feature An element, such as a land or water form, vegetation, or structure in the seen landscape.
Visual harmony A pleasing array of visual elements in a landscape, usually as a result of a sense of visual order, compatibility, and completeness between and among the…
Visual impact Any modification in land forms, water bodies, or vegetation, or any introduction of structures, which negatively or positively affect the visual character…
Visual intrusion Any human-caused change in the land form, water form, vegetation, or the addition of a structure which creates a visual contrast in the basic elements…
Visual mitigation Actions taken to avoid, eliminate, or reduce potential adverse impacts on scenic resources.
Visual quality See Scenic quality
Visual Resource Inventory (VRI) Consists of a scenic quality evaluation, sensitivity level analysis, and a delineation of distance zones.
Visual Resource Inventory (VRI) Classes VRI Classes are assigned to public lands based upon the results from the Visual Resource Inventory.
Visual Resource Management (VRM) Class Designations Class I objective is to preserve the existing character of the landscape. The level of change to the characteristic landscape should be very low and must…
Visual Resource Management (VRM) Classes Categories assigned to BLM lands, utilizing the Visual Resource Inventory Classes in the RMP process, with an objective which prescribes the amount of…
Visual Resource Management (VRM) System BLM's system for minimizing the visual impacts of surface-disturbing activities and maintaining scenic values for the future.
Visual resources Refers to all objects (man-made and natural, moving and stationary) and features such as landforms and water bodies that are visible on a landscape.
Visual sensitivity Public concern for the maintenance of scenic quality in a particular landscape setting.
Visual unity The quality or state of appearing to be united in principles and relationships or to be logically and aesthetically connected because of the visual…
Visual value See Scenic value
Voice broker A trading intermediary matching buyers and sellers using traditional telephone confirmation.
volatile A solid or liquid material that easily vaporizes.
volatile matter Those products, exclusive of moisture, given off by a material as a gas or vapor, determined by definite prescribed methods that may vary according to the…
Volatile organic compound (VOC) Any organic compound that participates in atmospheric photochemical reactions except those designated by the EPA as having negligible photochemical…
Volatile organic compounds (VOC) Non-methane hydrocarbon gases. Released during combustion or evaporation of fuel.
Volatiles Substances that are readily vaporized.
Volatility The term volatility indicates how much and how quickly the value of an investment, market, or market sector changes.
Volcanic Ash Consists of rock, mineral, and volcanic glass fragments smaller than 2 millimeters (mm) (0.
Volcanic chain A linear sequence of volcanoes that occurs within a tectonic plate. As the plate moves over a stationary hot spot, new volcanoes are created.
Volcanic cone A landform built by the material ejected from a volcanic vent and piled up around the vent in the shape of a cone with a central crater.
Volcanic vent The opening at the Earth's surface through which volcanic materials issue forth.
Volcanic-rock aquifer See Aquifer-volcanic rock
Volcanism The process by which magma and associated gases rise to the Earth's crust and are extruded, or expelled, onto the surface and into the atmosphere.
Volcano A vent (opening) in the surface of the Earth through which magma erupts. It is also the landform that is constructed by the erupted material.
Volcanoclastic rock Sedimentary rocks such as sandstones formed by the aggregation of rock fragments (clasts) of volcanic origin.
Volt A unit of electrical force equal to that amount of electromotive force that will cause a steady current of one ampere to flow through a resistance of one…
Volt-Ampere A unit of electrical measurement equal to the product of a volt and an ampere.
Voltage The amount of electromotive force, measured in volts, that exists between two points.
Voltage reduction Any intentional reduction of system voltage by 3 percent or greater for reasons of maintaining the continuity of service of the bulk electric power supply…
Volumetric risk The effect on revenue of fluctuations in demand for a product or service.
Voluntary relinquishment To voluntarily relinquish possession with the intent of terminating ownership, but without vesting it in any other person.