Science — page 57 of 132

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

Subtopics

Science terms

  1. Heat transfer efficiency The useful heat output released to a room divided by the actual heat produced in the firebox.
  2. Heat Transfer Fluid A gas or liquid used to move heat energy from one place to another; a refrigerant.
  3. Heat transfer fluid (HTF) (HTF) Fluids that transfer heat generated at the solar collectors to a heat exchanger where steam is produced to run a steam generator.
  4. Heat Transmission Coefficient Any coefficient used to calculate heat transmission by conduction, convection, or radiation through materials or structures.
  5. Heat Wave A period of abnormally and uncomfortably hot and unusually humid weather. Typically a heat wave lasts two or more days.
  6. Heating Capacity (Also specific heat) The quantity of heat necessary to raise the temperature of a specific mass of a substance by one degree.
  7. Heating Degree Day(s) (HDD) The number of degrees per day that the daily average temperature (the mean of the maximum and minimum recorded temperatures) is below a base temperature…
  8. Heating Degree Days (abbrev. HDD) A form of degree day used to estimate energy requirements for heating.
  9. Heating degree days (HDD) (HDD) A measure of heating demand equal to the number of degrees a location’s mean daily temperature was below 65 degrees Fahrenheit.
  10. Heating Fuel Units Standardized weights or volumes for heating fuels.
  11. Heating Fuels Any gaseous, liquid, or solid fuel used for indoor space heating.
  12. Heating Load The rate of heat flow required to maintain a specific indoor temperature; usually measured in Btu per hour.
  13. Heating Season The coldest months of the year; months where average daily temperatures fall below 65 degrees Fahrenheit creating demand for indoor space heating.
  14. Heating Seasonal Performance Factor (HSPF) (HSPF) The measure of seasonal or annual efficiency of a heat pump operating in the heating mode.
  15. Heating Value The amount of heat produced from the complete combustion of a unit of fuel. The higher (or gross) heating value is that when all products of combustion…
  16. Heating, Ventilation, and Air-Conditioning (HVAC) System All the components of the appliance used to condition interior air of a building.
  17. Heave The upward movement of land surfaces or structures due to subsurface expansion of soil or rock, or vertical faulting of rock.
  18. Heavenly Bodies Any mass or object in space, including nebulas, planets, moons, stars, pulsars, quasars and so on.
  19. Heavy Freezing Spray An accumulation of freezing water droplets on a vessel at a rate of 2 cm per hour or greater caused by some appropriate combination of cold water, wind…
  20. Heavy Freezing Spray Warning A warning that may be issued within the Offshore Waters Forecast, the Coastal Waters Forecast, the Nearshore Marine Forecast, and the Open Lake Forecast…
  21. Heavy metals Metallic elements with high atomic weights (e.g., mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend…
  22. Heavy Snow This generally means... snowfall accumulating to 4" or more in depth in 12 hours or less; or snowfall accumulating to 6" or more in depth in 24 hours or…
  23. Heavy Snow Warning Issued by the National Weather Service when snowfall of 6 inches (15 cm) or more in 12 hours or 8 inches (20 cm) or more in 24 hours is imminent or…
  24. Heavy Surf Advisory An advisory issued by the National Weather Service for fast moving deep water waves which can result in big breaking waves in shallow water (the surf…
  25. Hectare An area equal to 2.47 acres. There are 100 hectares in 1 square kilometer.
  26. Hectopascal A unit of pressure equal to a millibar (1 hPa = 1 mb). Abbreviated hPa.
  27. Hedging Hedging is an investment technique designed to offset a potential loss on one investment by purchasing a second investment that you expect to perform in…
  28. Hedonic – (modeling approach) The hedonic method is a regression technique used to estimate the prices of qualities or models that are not available on the market in particular…
  29. Hedonic statistical framework A method of assessing the impact of various structural (number of bedrooms, bathrooms, square footage, age, etc.
  30. Heel of Dam The junction of the upstream face of a concrete gravity dam or arch dam with the ground surface.
  31. Height In meteorology, usually a reference to Geopotential Height; roughly the height above sea level of a pressure level.
  32. Height of dam. See hydraulic height or structural height.
  33. Heinrich Events periods of increased discharge of icebergs from the margin of ice sheets into the North Atlantic Ocean during the last glacial.
  34. Helical Spiral.
  35. Helicity A property of a moving fluid which represents the potential for helical flow (i.e. flow which follows the pattern of a corkscrew) to evolve.
  36. Heliocentric A model of the universe published by Nicolaus Copernicus, and proven by Galileo (who viewed the phases of venus with his telescope), which puts our sun at…
  37. Heliochemical Process The utilization of solar energy through photosynthesis.
  38. Heliodon A device used to simulate the angle of the sun for assessing shading potentials of building structures or landscape features.
  39. Heliosphere A huge magnetic bubble containing the solar wind and the entire solar magnetic field.
  40. Heliostat A device that tracks the movement of the sun; used to orient solar concentrating systems.
  41. Heliothermal Any process that uses solar radiation to produce useful heat.
  42. Heliothermic Site planning that accounts for natural solar heating and cooling processes and their relationship to building shape, orientation, and siting.
  43. Heliothermometer An instrument for measuring solar radiation.
  44. Heliotropic Any device (or plant) that follows the sun's apparent movement across the sky.
  45. helix A structure with a spiral shape. The normal state of double-stranded DNA is in the form of a double helix.
  46. helminth A class of parasitic worms, especially those which are internal parasites of man and animals.
  47. helper cell T cells that assist in stimulating B and T lymphocyte s to develop into antibody-producing plasma cells and killer T cells, respectively.
  48. helper plasmid A plasmid that provides a function or functions to another plasmid in the same cell.
  49. helper T cell A type of white blood cell that helps stimulate immune system reactions. Helper T cells help activate cytotoxic T cells and macrophages by secreting…
  50. helper T lymphocyte See: helper cell.
  51. helper virus A virus that provides a function or functions to another virus in the same cell.
  52. Hematological Oncologist A medical doctor who specializes in diagnosing and treating malignancies, or cancers, of the blood and blood- forming tissues.
  53. Hematologist (HEE-muh-TAH-loh-jist) A doctor who specializes in treating blood disorders.
  54. Hematopoiesis (hee-MA-toh-poy-EE-sus) The formation of new blood cells.
  55. Hematopoietic cell transplantation The transplantation of hematopoietic stem cells with blood-forming potential. Hematopoietic stem cells provide rapid and sustained reconstitution of blood…
  56. Hematopoietic stem cell An unspecialized precursor cell that will develop into a mature blood cell. See also cell
  57. Hematopoietic stem cell (HSC) A stem cell from which all red and white blood cells evolve.
  58. Hematopoietic stem cells The precursors of mature blood cells that are defined by their ability to replace the bone marrow system following its obliteration (for example, by…
  59. hemicellulase An enzyme that catalyses the degradation of hemicellulose.
  60. hemicellulose Any cellulose-like carbohydrate, but excluding cellulose itself. Together with pectin and lignin, hemicelluloses form the cell wall matrix.
  61. Hemispherical Bowl Technology A solar energy concentrating technology that uses a linear receiver that tracks the focal area of a reflector or array of reflectors.
  62. Hemizygous The condition in which genes are present only once in the genotype and not in pairs.
  63. hemoglobin (HEE-moh-GLOH-bin) The substance inside red blood cells that binds to oxygen in the lungs and carries it to the tissues.
  64. hemolymph See: haemolymph.
  65. hemophilia Group of hereditary disorders in which affected individuals fail to make enough of certain proteins needed to form blood clots.
  66. Henry Hub A location near the coastal town of Egan, LA and the Texas border where more than a dozen major natural gas pipelines converge and exchange gas.
  67. HEPA filter Abbreviation for high efficiency particulate air filter. A filter capable of excluding particles larger than 0.3ìm.
  68. Hepatic (hih-PA-tik) Refers to the liver.
  69. Hepatocyte (HEP-a-toe-site) A liver cell.
  70. Herbaceous The plant strata that contain soft, not woody, stemmed plants that die to the ground in winter.
  71. herbaceous energy crops Perennial non-woody crops that are harvested annually, though they may take two to three years to reach full productivity.
  72. herbaceous plants Non-woody species of vegetation, usually of low lignin content such as grasses.
  73. Herbicide A chemical that kills plants.
  74. herbicide resistance The ability of a plant to remain unaffected by the application of a herbicide.
  75. Herbicide-tolerant crop Crop plants that have been developed to survive application(s) of one or more commercially available herbicides by the incorporation of certain gene(s)…
  76. Herbivore Animal that feeds on plants.
  77. Herd Area (HA) (HA) Following passage of the Wild Free-Roaming Horses and Burros Act (WFRHBA) in 1971, the Bureau of Land Management was directed to identify areas where wild…
  78. Herd Management Area (HMA) (HMA) An area that has been designated for management of wild horses and/or burros.
  79. Hereditary cancer Cancer that occurs due to the inheritance of an altered gene within a family. See also: sporadic cancer
  80. heredity Resemblance among individuals related by descent; transmission of traits from parents to offspring.
  81. heritability The degree to which a given trait is controlled by inheritance, as opposed to being controlled by non-genetic factors.
  82. heritable genetic effects Genetic damage caused by an external agent such as radiation, which manifests itself in the gene carrier and is capable of being passed on to succeeding…
  83. hermaphrodite 1. An animal that has both male and female reproductive organs, or a mixture of male and female attributes. 2.
  84. Herpetofauna Amphibian and reptile species including frogs, toads, salamanders, turtles, lizards, and snakes.
  85. Hertz A measure of the number of cycles or wavelengths of electrical energy per second; U.S. electricity supply has a standard frequency of 60 hertz.
  86. Hertz (Hz) (Hz) The unit of measurement of frequency, equivalent to one cycle per second.
  87. hES cell Human embryonic stem cell; a type of pluripotent stem cell.
  88. heteroallele A gene having mutations at two or more different sites.
  89. Heterochromatin Dark-stained regions of chromosomes thought to be for the most part genetically inactive.
  90. Heteroduplex A double-stranded DNA molecule or DNA-RNA hybrid, where each strand is of a different origin.
  91. heteroduplex analysis The use of the electrophoretic mobility of to estimate the degree of non-homology between the sequences of the two strands.
  92. heterogametic Producing unlike gametes with regard to the sex chromosomes. In mammals, the XY male is heterogametic, and the XX female is homogametic.
  93. Heterogeneity See: genetic heterogeneity.
  94. heterogeneous nuclear RNA (Abbreviation: hnRNA ). Large RNA molecules, which are found in the nucleus of a eukaryotic cell and the precursors of mRNA and other RNA molecules.
  95. Heterogeneous nuclear RNA (hnRNA) The name originally given to large RNA molecules found in the nucleus, which are now known to be unedited mRNA transcripts, or pre-mRNAs. (See RNA.)
  96. Heterojunction A region of electrical contact between two different materials.
  97. heterokaryon A cell with two or more different nuclei as a result of cell fusion. See: synkaryon.
  98. Heterologous From a different source.
  99. heterologous probe A DNA probe that is derived from one species and used to screen for a similar DNA sequence from another species.
  100. heterologous protein See: recombinant protein.