galactanThe polymer of galactose with a repeating unit of C6H10O5. Found in hemicellulose it can be hydrolyzed to galactose.
galactoseA six-carbon sugar with the formula C6H1206. A product of hydrolysis of galactan found in the hemicellulose fraction of biomass.
Gallium (Ga)A chemical element, metallic in nature, used in making certain kinds of solar cells and semiconductor devices.
gapA missing section on one of the strands of double-stranded DNA. The DNA will therefore have a single-stranded region.
Gas engineA piston engine that uses gaseous fuel rather than gasoline. Fuel and air are mixed before they enter cylinders; ignition occurs with a spark.
Gas shift processA process in which carbon monoxide and hydrogen react in the presence of a catalyst to form methane and water.
Gas turbineA type of turbine in which combusted, pressurized gas is directed against a series of blades connected to a shaft, which forces the shaft to turn to…
GasificationThe process in which a solid fuel is converted into a gas; also known as pyrolitic distillation or pyrolysis.
GasifierA device for converting a solid fuel to a gaseous fuel.
GasoholA registered trademark of an agency of the state of Nebraska, for an automotive fuel containing a blend of 10 percent ethanol and 90 percent gasoline.
GDAsSee Renewable Resource Generation Development Areas
Generalist (species)An organism that can survive under a wide variety of conditions, and does not specialize to live under any particular set of circumstances.
GeneratorA device for converting mechanical energy to electrical energy.
GeoglyphsGround markings of a figure or shape produced by the clearing or alignment of stones.
Geographic air basin: A land area with generally similar meteorological and geographic conditions throughout.
Geographic Information System (GIS)A set of computer tools and procedures used to collect, manage, analyze and display information associated with a specific location; a computerized…
GeologyThe science that deals with the study of the materials, processes, environments, and history of the Earth, including the rocks and their formation and…
Geometric spreadingAs the sound moves away from the source, the area that the sound energy covers becomes larger and thus sound intensity decreases.
GeomorphicPertaining to those processes that affect the form or shape of the surface of the earth.
GeotechnicalRefers to the use of scientific methods and engineering principles to acquire, interpret, and apply knowledge of earth materials for solving engineering…
Geotextile matsPermeable fabrics that interact with soils in manners used to reinforce soil surfaces for erosion, as well as act as filters for water, solutes, and fine…
Geothermal energyEnergy produced by the internal heat of the earth; geothermal heat sources include: hydrothermal convective systems; pressurized water reservoirs; hot dry…
Geothermal generating plantA plant in which the prime mover is a steam turbine. The turbine is driven either by steam produced from hot water or by natural steam that derives its…
Geothermal resourcesTypically underground reservoirs of hot water or steam created by heat from the Earth, but also include subsurface areas of dry hot rock.
Glacial tillAn unsorted, unstratified mixture of fine and coarse rock debris deposited by a glacier.
GlareThe excessive brightness from a direct light source that makes it difficult to see what one wishes to see.
GlintA momentary flash of light resulting from a spatially localized reflection of sunlight. See also Glare
Global WarmingA popular term used to describe the increase in average global temperatures due to the greenhouse effect.
glucanThe polymer of glucose with a repeating unit of C6H10O5. Cellulose is a form of glucan. Can be hydrolyzed to glucose. (Source: Voet, D.; Voet, J. G.
glucoseA type of sugar; the chief source of energy for living organisms.
glycerin(C3H8O3) A liquid by-product of biodiesel production. Glycerin is used in the manufacture of dynamite, cosmetics, liquid soaps, inks, and lubricants.
gr/SCFGrains of pollutant per standard cubic foot of gas. A measure of dust particles in a gas stream.
Graben (fault-bounded basins)An elongated crustal block that is relatively depressed (down dropped) between two parallel normal faults or horsts. See also Half-graben
Graminoid herbaceousA grass or plant of similar growth form, such as sedges, rushes, and others.
Grandfathered rightsIn Arizona, grandfathered water rights are based on historic use of groundwater for five years prior to the designation of an Active Management Area.
GraniteA coarse-grained felsic intrusive (or plutonic) igneous rock with at least 65% silica.
GranodioritesA plutonic igneous rock, formed by an intrusion of silica-rich magma, which cools in batholiths or stocks below the Earth's surface.
GrasslandsGrasslands are characterized as lands dominated by grasses rather than large shrubs or trees.
GraverA small tool with a sharp tip that was used to engrave bone, stone, wood, or other materials.
GrazingConsumption of native forage from rangelands or pastures by livestock or wildlife.
Grazing allotmentAn area where one or more livestock operators graze their livestock. An allotment generally consists of federal land but may include parcels of private or…
Grazing leaseAn authorization that permits the grazing of livestock on public lands outside the grazing districts during a specified period of time (Section 15 of the…
Great BasinAn area covering most of Nevada and much of western Utah, as well as portions of southern Oregon and southeastern California, consisting primarily of…
Green loggingThe logging of timber that is still alive.
Green ton2,000 pounds of undried biomass material. Moisture content must be specified if green tons are used as a measure of fuel energy.
Greenhouse EffectA popular term used to describe the heating effect due to the trapping of long wave (length) radiation by greenhouse gases produced from natural and human…
Greenhouse GasSome greenhouse gases, which contribute to the greenhouse effect, occur naturally in the atmosphere while others result from human activities such as the…
Greenhouse gase (GHG)Heat-trapping gases that cause global warming. Natural and human-made greenhouse gases include water vapor, carbon dioxide, methane, nitrogen oxides…
Greenhouse GasesThose gases, such as water vapor, carbon dioxide, tropospheric ozone, methane, and low level ozone that are transparent to solar radiation, but opaque to…
GridA common term referring to an electricity transmission and distribution system.
Grid connectionJoining a plant that generates electric power to a utility system so that electricity can flow in either direction between the utility system and the…
Gross heating value (GHV)The maximum potential energy in the fuel as received, considering moisture content (MC). It reflects the heat used to evaporate moisture.
GroundA device used to protect the user of any electrical system or appliance from shock.
Ground failurePermanent ground displacement capable of damaging structures that may occur as a result of differential settlement, liquefaction, lateral spreading, or…
Ground fault matsMats made of insulating materials that do not conduct electricity.
Ground motion (shaking)The movement of the Earth's surface from earthquakes. Ground motion is produced by seismic waves that are generated by a sudden slip on a fault and travel…
GroundwaterAll water below the surface of the land. It is water found in the pore spaces of bedrock or soil, and it reaches the land surface through springs or it…
Groundwater basin: (1) A general term used to define a groundwater flow system that has defined boundaries and may include permeable materials that are capable of storing…
Groundwater overdraftThe condition in which water extractions from an aquifer exceed recharge processes in such excess as to cause substantial and sustained decreases in…
Groundwater rechargeInflow of water to a ground-water reservoir from the surface. Infiltration of precipitation and its movement to the water table is one form of natural…