Topographic mapA map indicating surface elevation and slope. U.S. Geological Survey quadrangle series maps showing the shape of the earth's surface by contours.
TopographyThe shape of the Earth's surface; the relative position and elevations of natural and human-made features of an area.
Topping and back pressure turbinesTurbines which operate at exhaust pressure considerably higher than atmospheric (noncondensing turbines).
Topping cycleA means to increase the thermal efficiency of a steam electric generating system by increasing temperatures and interposing a device, such as a gas…
TopsoilThe topmost layer of soil, usually containing organic matter. Usually refers to soil containing humus which is capable of supporting plant growth.
TornadoA violently rotating column of air, usually pendant to a cumulonimbus, with circulation reaching the ground.
Tornado FamilyA series of tornadoes produced by a single supercell, resulting in damage path segments along the same general line.
Tornado Vortex SignatureAn image of a tornado on the Doppler radar screen that shows up as a small region of rapidly changing wind speeds inside a mesocyclone.
Tornado WarningThis is issued when a tornado is indicated by the WSR-88D radar or sighted by spotters; therefore, people in the affected area should seek safe shelter…
Tornado WatchThis is issued by the National Weather Service when conditions are favorable for the development of tornadoes in and close to the watch area.
Torque (Motor)The turning or twisting force generated by an electrical motor in order for it to operate.
Total capacityThe reservoir capacity below the highest of the elevations representing either the top of exclusive flood control capacity, the top of joint use capacity…
total carbonThe total concentration of carbon in all its organic and non-organic forms.
total cloud waterThe total concentration (mass/vol) of ice and liquid water particles in a cloud.
Total dissolved solids (TDS)The dry weight of dissolved material, organic and inorganic, contained in water. The term is used to reflect salinity.
Total dynamic head (TDH)When a pump is lifting or pumping water, the vertical distance from the elevation of the energy grade line on the suction side of the pump to the…
Total Gross Reservoir CapacityThe total amount of storage capacity available in a reservoir for all purposes from the streambed to the normal water or normal water or normal pool…
Total Harmonic DistortionThe measure of closeness in shape between a waveform and it's fundamental component.
Total HeatThe sum of the sensible and latent heat in a substance or fluid above a base point, usually 32 degrees Fahrenheit.
Total Incident RadiationThe total radiation incident on a specific surface area over a time interval.
Total Internal ReflectionThe trapping of light by refraction and reflection at critical angles inside a semiconductor device so that it cannot escape the device and must be…
total ligninThe sum of the acid soluble lignin and acid insoluble lignin fractions.
Total maximum daily loads (TMDL)Estimates of the amount of specific pollutants that a body of water can safely take without threatening beneficial uses.
Total Solar IrradianceThe total amount of radiant energy from the Sun that falls on a surface in a given amount of time.
total solidsThe amount of solids remaining after all volatile matter has been removed from a biomass sample by heating at 105°C to constant weight.
Total suspended particulates (TSP)The quantity of solid particles in a gas or exhaust stream. Any finely divided material (solid or liquid) that is airborne with a diameter smaller than a…
Total-Totals IndexA stability index and severe weather forecast tool, equal to the temperature at 850 mb plus the dew point at 850 mb, minus twice the temperature at 500 mb.
Totalizer (integrator)A device or meter that continuously measures and calculates (adds) total flow.
totipotencyThe ability of a cell or tissue to be induced to regenerate into a complete organism.
TotipotentHaving to do with cells that are able to develop into any type of cell found in the body.
Totipotent stem cellsStem cells that can give rise to all cell types that are found in an embryo, fetus, or developed organism, including the embryonic components of the…
Towering CumulusA large cumulus cloud with great vertical development, usually with a cauliflower-like appearance, but lacking the characteristic anvil of a Cb.
Toxic substancesA chemical or mixture of chemicals that presents a high risk of injury to human health or to the environment.
Toxic Substances Control Act (TSCA)The Toxic Substances Control Act (TSCA), passed in 1976, requires tests of chemicals that may harm human health or the environment; reviews of new…
toxicity(tok-SIH-sih-tee) The extent to which something is poisonous or harmful.
ToxicogenomicsThe study of how genomes respond to environmental stressors or toxicants. Combines genome-wide mRNA expression profiling with protein expression patterns…
toxicsAs defined in the 1990 Clean Air Act Amendments, toxics include benzene, 1,3 butadiene, formaldehyde, acetaldehyde, and polycyclic organic matter.
toxin(TOK-sin) A poison produced by certain animals, plants, or bacteria.
TPC(Tropical Prediction Center) - An NCEP center which produces marine offshore and high seas forecasts south of 30N in the Eastern Pacific, Gulf of Mexico…
TraceA hydrograph or similar plot for an extended-range time horizon showing one of many scenarios generated through an ensemble forecast process.
Trace GasAny one of the less common gases found in the Earth's atmosphere. Nitrogen, oxygen, and argon make up more than 99 percent of the Earth's atmosphere.
tracerA substance (such as a radioisotope) used in imaging procedures.
tracheidAn elongated, tapering xylem cell, with lignified pitted walls, adapted for solute conduction and physical support.
TrackEach of the series of concentric rings contained on a hard drive platter.
Tracking arrayA PV panel array that follows the path of the sun to maximize the solar radiation incident on the PV surface.
Tracking Solar ArrayA solar energy array that follows the path of the sun to maximize the solar radiation incident on the PV surface.
Tractor gateRectangular gate supported and sealed similar to the paradox gate. Main difference is that the leaf is raised and lowered by a cable hoist, and operated…
Trade WindsPersistent tropical winds that blow from the subtropical high pressure centers towards the equatorial low.
Traditional breedingModification of plants and animals through selective breeding. Practices used in traditional plant breeding may include aspects of biotechnology such as…
Traditional cultural propertyA property that is eligible for inclusion in the National Register of Historic Places because of its association with cultural practices or beliefs of a…
Traditional cultural property (TCP)A site or resource that is eligible for inclusion in the National Register of Historic Places because of its association with cultural practices or…
Traditional NeighborhoodsTraditional neighborhood development emphasizes two broad goals: to reduce the destruction of habitat and natural resources, and to reduce dependency on…
Traffic control pointA location staffed to ensure the continued movement of traffic inside or outside an area of risk during an emergency or disaster.
Trailing EdgeThe part of a wind energy conversion device blade, or airfoil, that is the last to contact the wind.
TrainingRepeated areas of rain, typically associated with thunderstorms, that move over the same region in a relatively short period of time and are capable of…
Training wallA wall built to confine or guide the flow of water.
Tranquil flowDistinguished from rapid flow by a dimensionless number called the Froude number. If the Froude number is less than one, the flow is tranquil.
trans-acting1. A term describing substances that are diffusable and that can affect spatially separated entities within cells. 2. A genetic element (e.g.
trans-acting factorAny of the multiple ancillary DNA -binding proteins that interact with the cis-regulatory DNA sequences to control gene expression.
Transaction costsCosts, such as commissions and spreads, incurred when buying or selling assets. Large bid-ask spreads are an indication of high transaction costs.
TransaminaseAn enzyme that catalyzes chemical reactions in the body in which an amino group is transferred from a donor molecule to a recipient molecule.
TranscapsidationThe partial of full coating of the nucleic acid of one virus with a coat protein of a differing virus. See Coat protein.
Transcripta written copy of spoken or recorded material which is the official or legal copy of a court hearing, also called a court reporter’s transcript.
TranscriptionIn biology, the process by which a cell makes an RNA copy of a sequence of DNA that is a gene.
Transcription factorsSpecialized proteins that bind to specific sites on DNA and turn on or turn off the expression of different sets of genes.
transcription unitA segment of DNA that contains signals for the initiation and termination of transcription, and is transcribed into one RNA molecule.
transcriptional anti-terminatorA protein that prevents RNA polymerase from terminating transcription at specific transcription termination sequences.
transcriptional roadblockA DNA -binding protein which affects the rate at which RNA polymerases transcribe genes.
TranscriptomeThe full complement of activated genes, mRNAs, or transcripts in a particular tissue at a particular time
TransdifferentiationThe ability of a particular cell of one tissue, organ or system, including stem or progenitor cells, to differentiate into a cell type characteristic of…
transducerA device that converts electrical energy to sound energy, or the reverse. Typically associated with depth finders or fish finders.
TransductionThe transfer of DNA sequences from one bacterium to another via lysogenic infection by a bacteriophage (transducing phage).
transesterificationA chemical process which reacts an alcohol with the triglycerides contained in vegetable oils and animal fats to produce biodiesel and glycerin.
TransfectionThe uptake and expression of a foreign DNA sequence by cultured eukaryotic cells.
Transfer of Development Rights (TDR)A system that assigns development rights to parcels of land and gives landowners the option of using those rights to develop or to sell their land.
TransformantIn prokaryotes, a cell that has been ge- netically altered through the uptake of foreign DNA.
transformation(TRANZ-for-MAY-shun) In medicine, the change that a normal cell undergoes as it becomes malignant.
Transformation efficiencyThe number of bacterial cells that uptake and express plasmid DNA divided by the mass of plasmid used (in transformants/microgram). (See Transformation.)
transformation efficiency or frequencyThe fraction of a cell population that takes up and integrates the introduced transgene; expressed as the number of transformed cells recovered divided by…
Transformed flow netA flow net whose boundaries have been properly modified (transformed) so that a net consisting of curvilinear squares can be constructed to represent flow…