Science — page 114 of 132

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

Science terms

Stand conversion The conversion of a noncommercial stand of timber to a commercial stand.
Stand density The number or mass of trees occupying a site. It is usually measured in terms of stand density index or basal area per acre.
Stand-Alone Generator A power source/generator that operates independently of or is not connected to an electric transmission and distribution network; used to meet a load(s)…
Stand-Alone Inverter An inverter that operates independent of or is not connected to an electric transmission and distribution network.
Stand-Alone System An system that operates independent of or is not connected to an electric transmission and distribution network.
Stand-by Heat Loses A term used to describe heat energy lost from a water heater tank.
Stand-By Power For the consumer, this is the electricity that is used by your TVs, stereos, and other electronic devices that use remote controls.
Standard Air Air with a weight of 0.075 pounds per cubic foot with an equivalent density of dry air at a temperature of 86 degrees Fahrenheit and standard barometric…
Standard Atmosphere A hypothetical vertical distribution of atmospheric temperature, pressure, and density that, by international agreement, is taken to be representative of…
Standard Candle A celestial object whose intrinsic brightness is known or can be estimated by some physical principle.
Standard Conditions In refrigeration, an evaporating temperature of 5 degrees Fahrenheit (F), a condensing temperature of 86 degrees F.
Standard Cubic Foot A column of gas at standard conditions of temperature and pressure (32 degrees Fahrenheit and one atmosphere).
Standard deviation Standard deviation is a statistical measurement of how far a variable quantity, such as the price of a stock, moves above or below its average value.
standard error The standard error of an estimate is a measure of the sampling variability of the estimate.
Standard Hydrologic Exchange Format (SHEF) (SHEF) A documented set of rules for coding data for operational day-to-day use in a form for both visual and computer recognition.
Standard Industrial Classification (SIC) Code Standardized codes used to classify businesses by type of activity they engage in.
Standard Synoptic Times The times of 0000, 0600, 1200, and 1800 UTC. Also known as the main synoptic times.
Standards and guidelines Bounds or constraints within which all practices in a given area will be carried out, in achieving the goals and objectives for that area.
Standby reserves Unused capacity in an electric system in machines that are not in operation but that are available for immediate use if required.
Standing Operating Procedures (SOP) A comprehensive single-source document covering all aspects of dam and reservoir operation and maintenance and emergency procedures.
Standpipe Pipe or tank connected to a closed conduit and extending to or above the hydraulic grade line of the conduit to afford relief from surges of pressure in…
starch A substance found in plants. It contains sugar molecules joined chemically. It is found in high levels in foods such as potatoes, rice, corn, and wheat.
StarLinkTM An insect-resistant variety of corn that was approved for animal feed only, not labeled for human consumption.
start codon The codon which specifies the first amino acid of a polypeptide chain and at which the ribosome starts the process of translation.
starter culture Micro-organisms that are deliberately added to foods to alter flavour, colour, texture, smell, or taste.
Starting Surge Power, often above an appliance's rated wattage, required to bring any appliance with a motor up to operating speed.
Starting Torque The torque at the bottom of a speed (rpm) versus torque curve. The torque developed by the motor is a percentage of the full-load or rated torque.
State Emergency Response Commission (SERC) Appointed by the governor of each state for the designation of emergency planning districts, appoint LEPC's, supervise and coordinate their activities…
State Forecast Product This National Weather Service product is intended to give a good general picture of what weather may be expected in the state during the next 5 days.
State Historic Preservation Officer (SHPO) (SHPO) The State officer charged with the identification and protection of prehistoric and historic resources in accordance with the National Historic…
State Implementation Plan (SIP) (SIP) A state plan required by the Clean Air Act to bring nonattainment areas into compliance with federal ambient air quality standards.
State organization The State government agency or office having the principal or lead role in emergency planning and preparedness.
State Tax Incentives Massachusetts offers tax incentives to individuals and business that install renewable energy systems at their homes or offices.
State Weather Roundup This is a National Weather Service tabular product which provides routine hourly observations within the state through the National Weather Wire Service…
Static Unchanging over a length of time.
Static head The difference in elevation between the pumping source and the point of delivery. The vertical distance between two points in a fluid.
Static Pressure The force per unit area acting on the surface of a solid boundary parallel to the flow.
Station Any one of a series of stakes or points indicating distance from a point of beginning or reference.
Station ID Five-digit WMO Station Identifier used by the Buoy Data Center since 1976. ID's can be reassigned to future deployments within the same 1 degree square.
Station Model A specified pattern for plotting, on a weather map, the meteorological symbols that represent the state of the weather at a particular observing station.
Station Pressure The absolute air pressure at a given reporting station. The air pressure is directly proportional to the combined weight of all air in the atmosphere…
Station use Energy used in a generating plant as necessary in production of electricity. Includes energy consumed for plant light, power, and auxiliaries regardless…
stationary culture A culture maintained without agitation.
Stationary Front A front between warm and cold air masses that is moving very slowly or not at all.
Stationary phase The plateau of the growth curve after log growth, during which cell number remains constant. New cells are produced at the same rate as older cells die.
stationary pressure A front between warm and cold air masses that is moving very slowly or not at all.
Stationary white noise Random energy with statistical characteristics that do not vary with time.
Stator That portion of a machine which contains the stationary (non-moving) parts that surround the moving parts (rotor).
Stator windings The armature or stationary winding of a synchronous generator.
STBL Stable
Steady flow Flow in an open channel is said to be steady if the depth of flow does not change over a given time interval. No change occurs with repect to time.
steady state In a continuous fermentation process, the condition under which the number of cells removed with the outflow is exactly balanced by the number of newly…
Steady state condition When model input values are nearly constant for a defined period of time.
Steady State Theory A cosmological model where matter is created constantly as the universe expands so it remains homogenous and isotropic.
Steam Water in vapor form; used as the working fluid in steam turbines and heating systems.
Steam amendment chemicals Chemicals used to treat raw water to remove certain chemical species, thus amending its hardness or pH, making it suitable for use in a steam cycle.
Steam Boiler A type of furnace in which fuel is burned and the heat is used to produce steam.
Steam conversion factors (approximations) 1 pound of steam = 1,000 Btu = .3 kW. 10,000 lbs/hr steam = 300 boiler horsepower.
Steam Fog Fog formed when water vapor is added to air which is much colder than the source of the vapor.
Steam plant A plant in which the prime mover is a steam turbine. The steam used to drive the turbine is produced in a boiler where fossil fuels are burned.
Steam Turbine A device that converts high-pressure steam, produced in a boiler, into mechanical energy that can then be used to produce electricity by forcing blades in…
Steam turbine-generator (STG) (STG) A device that uses high-pressure steam, produced in a boiler, to drive the blades of a turbine to produce mechanical energy that can then be used to…
Steel factor See stem cell factor.
Steep slopes Ground surface that rises precipitously above the horizon.
Steepness In marine terms, on a buoy report, wave steepness is the ratio of wave height to wave length and is an indicator of wave stability.
Steering Currents Same as Steering Winds; a prevailing synoptic scale flow which governs the movement of smaller features embedded within it.
Steering flow Steering flow A basic fluid flow which exerts a strong influence upon the direction of movement of disturbances embedded in it.
Steering Winds Same as Steering Currents; A prevailing synoptic scale flow which governs the movement of smaller features embedded within it.
stele The central vascular cylinder, inside the cortex, of roots and stems of higher plants.
stem The main body of the above-ground portion of a tree, shrub, herb or other plant; the ascending axis, whether above or below ground, of a plant.
Stem cell A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
Stem cell antigen 1 (Sca-1) Cell-surface protein on bone marrow cell, indicative of hematopoietic stem cells and mesenchymal stem cells.
Stem cell factor (SCF) Relatively undifferentiated cell that can continue dividing indefinitely, throwing off daughter cells that can undergo terminal differentiation into…
Stem cells cells that have the ability to divide for indefinite periods in culture and give rise to specialized cells.
Stemming Crushed stone, soil, sand, or drill cuttings used to plug the unloaded portion of a drill hole.
Steppe Habitat dominated by shrubs and grasses.
Stepped Leader A faint, negatively charged channel that emerges from the base of a thunderstorm and propagates toward the ground in a series of steps of about 1…
sterile (STER-il) Unable to produce children. Also means free from germs.
sterile room Dedicated space for the carrying out of activities that require sterile conditions.
sterility Complete or partial failure of an individual to produce functional gametes or viable zygotes under a given set of environmental conditions.
sterilize 1. The elimination of micro-organisms, using heat, irradiation, filtration or chemicals. 2.
Steward bottle Flask developed for the growth of cells and tissues in a liquid medium, in which they can be periodically submerged during rotation.
Stewardship Careful and responsible management to ensure that goals and objectives are being achieved for the benefit of current and future generations.
STFR Stratus Fractus
STG See Steam turbine generator
Sticky end A protruding, single-stranded nucleotide se- quence produced when a restriction endonuclease cleaves off center in its recognition sequence.
Sticky limit The lowest moisture content at which a soil will stick to a metal blade drawn across the surface of the soil mass.
stigma Receptive portion of the style, to which pollen adheres.
Still gas Any form or mixture of gases produced in refineries by distillation, cracking, reforming, and other processes.
Stillage The grains and liquid effluent remaining after distillation.
Stilling Basin Concrete portion downstream from conduit, tunnel, or control structure. A pool, usually lined with reinforced concrete, located below a spillway, gate, or…
Stilling pool A pool located below a spillway, gate, or valve into which the discharge dissipates energy to avoid downstream channel degradation.
Stirling Engine A heat engine of the reciprocating (piston) where the working gas and a heat source are independent.
stirred-tank fermenter A growth vessel in which cells or micro-organisms are mixed by mechanically-driven impellers.
STJ Subtropical Jet - this jet stream is usually found between 20° and 30° latitude at altitudes between 12 and 14 km.
STLT Satellite
STM Stratiform
STNRY Stationary
Stochastic Random.
stock A share of stock that represents ownership in the company that issues it. The price of the stock goes up and down, depending on how the company performs…