Science — page 106 of 132

13,110 terms including subtopics (0 terms filed directly here)

Science terms

Sealed Combustion Heating System A heating system that uses only outside air for combustion and vents combustion gases directly to the outdoors.
Seam A layer of rock, coal, or ore.
SEAS Secure Environment Access Solution
Seashore The coastline of a sea or ocean, including the ground between the ordinary high water and low water marks.
Seasonal Energy Efficiency Ratio (SEER) (SEER) A measure of seasonal or annual efficiency of a central air conditioner or air conditioning heat pump.
Seasonal Performance Factor (SPF) (SPF) Ratio of useful energy output of a device to the energy input, averaged over an entire heating season.
Seasonal stream. See intermittent stream.
Seasoned Wood Wood, used for fuel, that has been air dried so that it contains 15 to 20 percent moisture content (wet basis).
Secchi depth A measure of water clarity.
Second foot (sec-ft) Shortened term for cubic foot per second (cfs or ft3/s).
Second growth A second generation of timber of merchantable age.
Second Law Efficiency The ratio of the minimum amount of work or energy required to perform a task to the amount actually used.
Second Law of Thermodynamics This law states that no device can completely and continuously transform all of the energy supplied to it into useful energy.
Second-Day Feet The volume of water represented by a flow of one cubic foot per second for 24 hours; equal to 84,000 cubic feet.
Secondary Ambient Air Quality Standards Air quality standards designed to protect human welfare, including the effects on vegetation and fauna, visibility and structures.
secondary antibody In an ELISA or other immunological assay system, the antibody designed to bind to the primary antibody, and to which a label is generally attached.
secondary cell wall The innermost layer of cell wall, giving rigidity to the cells. Characterized by its highly organized microfibrillar structure, and only formed in certain…
Secondary containment A safeguarding method for the prevention of unauthorized releases of toxic or hazardous gases into uncontrolled work areas.
Secondary Embankment Embankment that blocks an area on a reservoiur rim that is lower than the top of the main dam. See also, "Levee".
secondary growth Type of growth characterized by an increase in the thickness of stem and root, and resulting from the formation of secondary s by the vascular cambium.
secondary immune response The rapid immune response that occurs during the second (and subsequent) encounters of the immune system of a mammal with a specific antigen.
secondary messenger A chemical compound within a cell that is responsible for initiating the response to a signal from a chemical messenger (such as a hormone) that cannot…
secondary metabolism The production by living organisms of substances not essential for primary metabolic functions or physiology.
secondary metabolite Product of secondary metabolism.
Secondary oil recovery Injection of water into an oil well after primary oil recovery to force out some of the remaining thicker crude oil.
secondary oocyte See: oocyte.
secondary phloem Phloem tissue formed by the vascular cambium during secondary growth in a vascular plant.
secondary plant product See: secondary metabolite.
Secondary Pollutant Pollutants generated by chemical reactions occurring within the atmosphere. Compare primary pollutant.
secondary root A branch or lateral root.
secondary spermatocyte See: spermatocyte.
secondary structure Localized three dimensional conformations adopted by macromolecules, in particular nucleic acids and polypeptides.
Secondary succession The progression of plant communities following disturbances such as fire, windthrow and timber harvesting. See Succession.
secondary thickening Deposition of secondary cell wall materials which result in an increase in thickness in stems and roots.
secondary vascular tissue Vascular tissue (xylem and phloem ) formed by the vascular cambium during secondary growth in a vascular plant.
secondary xylem See: secondary vascular tissue.
secretion The transport of a molecule from the inside of a cell through the cell membrane.
section An area equal to 640 acres or 1 square mile.
Sector A sector is a segment of the economy that shares distinctive characteristics, such as telecommunications or energy.
Sector Boundary In solar-terrestrial terms, in the solar wind, the area of demarcation between sectors, which are large-scale features distinguished by the predominant…
Sector Visibility The visibility in a specific direction that represents at least a 45Âº arc of a horizontal circle.
Sectorized Hybrid Scan A single reflectivity scan composed of data from the lowest four elevation scans. Close to the radar, higher tilts are used to reduce clutter.
Secular equilibrium A state of parent-daughter equilibrium which is achieved when the half-life of the parent is much longer than the half-life of the daughter.
Securite A headline within National Weather Service high seas forecasts transmitted via the GMDSS to indicate that no hurricane or hurricane force winds are…
Sedentism A term used to describe the process of settling down to live in groups for periods of time.
Sedge A grasslike plant with a triangular stem often growing in wet areas.
Sediment Any finely divided organic and/or mineral matter deposited by air or water in nonturbulent areas.
Sediment concentration The quantity of sediment relative to the quantity of transporting fluid, or fluid-sediment misture. The concentration may be by weight or by volume.
Sediment discharge Rate at which sediment passes a stream cross-section in a given period of time, expressed in millions of tons per day (mtd).
Sediment load Mass of sediment passing through a stream cross section in a specified period of time, expressed in millions of tons (mt).
Sediment Storage Capacity The volume of a reservoir planned for the deposition of sediment.
Sediment yield Amount of mineral or organic soil material that is in suspension, is being transported, or has been moved from its site of origin.
Sediment yield rate The sediment yield per unit of drainage area.
Sedimentary Rock resulting from the consolidation of loose eroded sediment, remains of organisms, or crystals forming directly from water.
Sedimentary rock Rock formed at or near the Earth's surface from the consolidation of loose sediment that has accumulated in layers through deposition by water, wind, or…
Sedimentation A process in which material carried in suspension by water flows into streams and rivers, increasing turbidity and eventually settling to the bottom.
Seebeck Effect The generation of an electric current, when two conductors of different metals are joined at their ends to form a circuit, with the two junctions kept at…
SEED Botanically, the matured ovule without accessory parts. Colloquially, anything which may be sown; i.e.
seed storage proteins Proteins accumulated in large amounts in protein bodies within seed s. They act as a source of amino acids during germination.
Seep A spot where ground water oozes slowly to the surface, usually forming a pool.
Seepage The act or process involving the slow movement of water or other fluid through a porous material such as soil or rock.
Seepage collar A projecting collar of concrete built around the outside of a tunnel or conduit, within an embankment dam, to reduce seepage along the outer surface of…
Seepage force The force transmitted to the soil or rock grains by seepage.
Seepage loss Water loss by capillary action and slow percolation.
Seepage velocity The rate of discharge of seepage water through a porous medium per unit area of void space perpendicular to the direction of the flow.
Seeps Wet areas, normally not flowing, arising from an underground water source. Any place where liquid has oozed from the ground to the surface.
segment-polarity gene A gene that functions to define the anterior and posterior components of body segments in Drosophila.
segregant An individual derived from a cross between two unlike parents.
segregation For genes, the separation of allele pairs from one another and their resulting assortment into different cells at meiosis.
Seiche A standing wave oscillation of water in large lakes usually created by strong winds and/or a large barometric pressure gradient.
Seiche wave A wave generated by either a landslide into a reservoir or by a sudden displacement or deformation of a fault line in a reservoir floor during a major…
Seismic Pertaining to any earth vibration, especially that of an earthquake.
Seismic evaluation criteria A guideline for determining which faults or seismic sources need to be assigned MCE's.
Seismic intensity Subjective measurement of the degree of shaking at a specified place by an experienced observer using a descriptive scale. See intensity scale.
Seismic parameters Descriptors of earthquake loading or earthquake size, such as magnitude, peak acceleration, location (distance and focal depth), spectrum intensity, or…
Seismic swarm See Swarm
Seismicity Refers to the geographic and historical distribution of earthquakes.
Seismo- Pertains to earthquakes.
Seismotectonic Of, relating to, or designating structural features of the earth which are associated with or revealed by earthquakes.
Seismotectonic Province A geographic area characterized by a combination of geology and seismic history.
Seize To bind wire rope with soft wire, to prevent it from ravelling when cut.
SEL A watch cancellation statement issued to terminate a watch before its original expiration time.
Select material Backfill materials specially selected and segregated from excavated materials.
selectable Having a gene product that, when present, enables the identification and preferential propagation of a particular genotype. See: reporter gene.
Selectable Load Any device, such as lights, televisions, and power tools, which is plugged into your central power source and used only intermittently.
Selectable marker A gene whose expression allows one to identify cells that have been transforrned or transfected with a vector containing the marker gene.
selection 1. Differential survival and reproduction of phenotypes . 2. A system for either isolating or identifying specific genotypes in a mixed population.
selection coefficient A measure of the intensity of selection at a locus, commonly abbreviated as s. It represents the proportionate reduction in the gametic contribution of a…
selection culture A selection based on difference(s) in environmental conditions or in culture medium composition, such that preferred variant cells or cell lines…
Selection cutting The periodic removal at short intervals of the oldest and largest trees in the stand, individually or in small groups.
selection differential The difference between the mean of the individuals selected to be parents and the mean of the overall population; it represents the average superiority of…
selection pressure The intensity of selection acting on a population of organisms or on cells in culture.
selection response The difference between the mean of the individuals selected to be parents and the mean of their offspring.
Selective Absorber A solar absorber surface that has high absorbence at wavelengths corresponding to that of the solar spectrum and low emittance in the infrared range.
Selective breeding Making deliberate crosses or matings of organisms so the offspring will have a desired characteristic derived from one of the parents.
Selective catalytic reduction (SCR) (SCR) Selective catalytic reduction (SCR) is a means of converting nitrogen oxides (NOx) into nitrogen (N2) and water (H20).
Selective Surface Coating A material with high absorbence and low emittance properties applied to or on solar absorber surfaces.
self-incompatibility In plants, the inability of the pollen to fertilize ovules (female gametes) of the same plant.
Self-pollination Pollen of one plant is transferred to the female part of the same plant or another plant with the same genetic makeup.
self-replicating elements Extrachromosomal DNA elements that have origins of replication for the initiation of their own DNA synthesis.