Science — page 60 of 132

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

Subtopics

Science terms

  1. hybrid system A renewable energy system that includes two different types of technologies that produce the same type of energy; for e.g.
  2. hybrid vigour The extent to which a hybrid individual outperforms both its parents with respect to one or many traits.
  3. Hybridization The hydrogen bonding of complementary DNA and/or RNA sequences to form a duplex molecule. (See Northern hybridization, Southern hybridization.)
  4. Hybridoma A hybrid cell, composed of a B Iymphocyte fused to a tumor cell, which grows indefinitely in tissue culture and is selected for the secretion of a…
  5. Hyder Flare In solar-terrestrial terms, a filiment-associated two-ribbon flare, often occurring in spotless regions.
  6. Hydraucone A draft tube in which the emerging water impinges on a plate.
  7. Hydraulic Powered by water. Having to do with water in motion.
  8. Hydraulic efficiency Efficiency of a pump or turbine to impart energy to or extract energy from water.
  9. Hydraulic fill Fill material that is transported and deposited using water.
  10. Hydraulic Fill Dam An embankment dam constructed of materials, often dredged, which are conveyed and/or placed by suspension in flowing water.
  11. Hydraulic fill structure A dam or impoundment made of hydraulic fill.
  12. Hydraulic Flow Atmospheric flow that is similar in character to the flow of water over an obstacle.
  13. Hydraulic Grade Line A line whose plotted ordinate position represents the sum of pressure head plus elevation head for the various positions along a given fluid flow path…
  14. Hydraulic grade line (HGL) (Hydraulic gradient) The hydraulic grade line lies below the energy grade line by an amount equal to the velocity head at the section.
  15. Hydraulic gradient In an aquifer, the rate of change of total head per unit of distance of flow at a given point and in a given direction.
  16. Hydraulic Head (1) The height of the free surface of a body of water above a given point beneath the surface.
  17. Hydraulic height Height to which the water rises behind the dam, and is the difference between the lowest point in the original streambed at the axis or the centerline…
  18. Hydraulic Jump A steady disturbance in the lee of a mountain, where the airflow passing over the mountain suddenly changes from a region of low depth and high velocity…
  19. Hydraulic load Amount of liquid going into a system.
  20. Hydraulic Mean Depth The right cross-sectional area of a stream of water divided by the length of that part of its periphery in contact with its containing conduit; the ratio…
  21. Hydraulic Permeability The flow of water through a unit cross-sectional area of soil normal to the direction of flow when the hydraulic gradient is unity.
  22. Hydraulic Radius The right cross-sectional area of a stream of water divided by the length of that part of its periphery in contact with its containing conduit; the ratio…
  23. Hydraulics Having to do with the mechanical properties of water in motion and the application of these properties in engineering.
  24. Hydric Characterized by, or thriving in, an abundance of moisture.
  25. Hydro-compactable, collapsible soil (settlement) Low-density soils that undergo appreciable loss of volume when wetted or subjected to increased load (or both).
  26. Hydrocarbon Any chemical compound containing hydrogen, oxygen, and carbon.
  27. Hydrocarbons Substances containing only hydrogen and carbon. Fossil fuels are made up of hydrocarbons.
  28. Hydrochlorofluorocarbons (HCFCs) Compounds containing hydrogen, fluorine, chlorine, and carbon atoms. Although ozone depleting substances, they are less potent at destroying stratospheric…
  29. hydrocracking A process in which hydrogen is added to organic molecules at high pressures and moderate temperatures; usually used as an adjunct to catalytic cracking.
  30. Hydroelectric plant Electric powerplant using falling water as its motive force. A power plant that produces electricity from the power of rushing water turning…
  31. Hydroelectric power The generation of electricity using falling water.
  32. Hydroelectric Power Plant A power plant that produces electricity by the force of water falling through a hydro turbine that spins a generator.
  33. Hydroelectric unit (hydrounit) An electric generator and turbine combination which is driven by water flow, thereby converting mechanical energy to electric energy.
  34. Hydrofluorocarbon (HFC) (HFC) Man-made chemicals, many of which have been developed as alternatives to ozone-depleting substances (ODSs) for industrial, commercial, and consumer…
  35. Hydrofluorocarbons (HFCs) Compounds containing only hydrogen, fluorine, and carbon atoms. They were introduced as alternatives to ozone depleting substances in serving many…
  36. Hydrogen A chemical element that can be used as a fuel since it has a very high energy content.
  37. Hydrogen bond A relatively weak bond formed between a hydrogen atom (which is covalently bound to a nitrogen or oxygen atom) and a nitrogen or oxygen with an unshared…
  38. hydrogen-uptake positive (Abbreviation: Hup+). A term describing a micro-organism that is capable of assimilating (or taking up) hydrogen gas.
  39. Hydrogenated Amorphous Silicon Amorphous silicon with a small amount of incorporated hydrogen. The hydrogen neutralizes dangling bonds in the amorphous silicon, allowing charge carriers…
  40. hydrogenation Treatment of substances with hydrogen and suitable catalysts at high temperature and pressure to saturate double bonds.
  41. Hydrogeochemistry Chemistry of ground water and surface water.
  42. Hydrogeologic conditions Conditions stemming from the interaction of ground water and the surrounding soil and rock.
  43. Hydrogeologic cycle The natural process of recycling water from the atmosphere down to (and through) the earth and back to the atmosphere again.
  44. Hydrogeologist A person who studies and works with ground water.
  45. Hydrogeology The geology of ground water, with particular emphasis on the chemistry and movement of water.
  46. Hydrograph A graphical representation of the stage or discharge as a function of time at a particular point on a watercourse; a time-discharge curve of the unsteady…
  47. Hydrograph Separation The process where the storm hydrograph is separated into baseflow components and surface runoff components.
  48. Hydrographic Survey An instrumental survey to measure and determine characteristics of streams and other bodies of water within an area, including such things as location…
  49. Hydrography Scientific study of physical aspects of all waters on the Earth's surface. Water features in 7.
  50. Hydrologic Budget An accounting of the inflow to, outflow from, and storage in, a hydrologic unit, such as a drainage basin, aquifer, soil zone, lake, reservoir, or…
  51. Hydrologic Cycle Cycle of water movement from atmosphere to Earth by precipitation and its return to the atmosphere by interception, evaporation, runoff, infiltration…
  52. hydrologic cycle (or water cycle) the combined fluxes of water occurring on, above, and below the surface of the earth.
  53. Hydrologic Equation The water inventory equation (Inflow = Outflow + Change in Storage) which expresses the basic principle that during a given time interval the total inflow…
  54. Hydrologic Model A conceptual or physically-based procedure for numerically simulating a process or processes which occur in a watershed.
  55. Hydrologic Operations Division (HOD) (HOD) The Hydrologic Operations Division of the Office of Hydrology (OH).
  56. Hydrologic Service Area HSA. A geographical area assigned to Weather Service Forecast Office's/Weather Forecast Office's that embraces one or more rivers.
  57. Hydrologic Service Area (HSA) (HSA) A geographical area assigned to Weather Service Forecast Office's/Weather Forecast Office's that embraces one or more rivers.
  58. Hydrologic Services A general term referring to the operations, products, verbal communications, and related forms of support provided by the NWS for the Nation's streams…
  59. Hydrologic Systems Branch (HSB) (HSB) The Hydrologic Systems Branch in the Office of Hydrology (OH).
  60. Hydrologic Unit A geographical area representing part or all of a surface drainage basin or distinct hydrologic feature such as a reservoir, lake, etc.
  61. Hydrologic unit code An eight-digit number used to identify a geographic area representing part or all of a surface drainage basin or distinct hydrologic feature.
  62. Hydrological Research Laboratory (HRL) (HRL) The Hydrological Research Laboratory at the Office of Hydrology (OH).
  63. Hydrologist on Duty (HOD) (HOD) The Hydrologist on Duty at an RFC.
  64. Hydrologists Individuals who study the applied science of hydrology and solve hydrologic problems.
  65. Hydrology The science dealing with the distribution, properties and circulation of water on land, in the soil, and in the atmosphere.
  66. Hydrolysis A chemical reaction that uses water to break down a compound.
  67. Hydromet A system of data collection platforms that gathers hydrometeorological data, and transmits that data via GOES Satelite to a computer downlink.
  68. Hydrometeor A particle of condensed water (liquid, snow, ice, graupel, hail) in the atmosphere.
  69. hydrometeor types Information that delineates hydrometeors into such microphysical classes as rain, snow, graupel, and hail.
  70. Hydrometeorological Automated Data System (HADS) (HADS) Software that replaced GDDS to process and distribute the GOES DCP data and CADAS data collected from DCP's and LARCS.
  71. Hydrometeorological Information Center (HIC) (HIC) The Hydrometeorological Information Center of the Office of Hydrology (OH).
  72. Hydrometeorological Report (HMR) A series of hydrometeorological reports published by the National Weather Service (NWS) addressing meteorological issues related mainly to developing…
  73. Hydrometeorological Technicians Individuals whose duties include data collection, quality control, gage network maintenance, as well as the gathering and disseminating of data and…
  74. Hydrometeorologists In hydrologic terms, individuals who have the combined knowledge in the fields of both meteorology and hydrology which enables them to study and solve…
  75. Hydrometeorology An inter­disci­plinary science involving the study and analysis of the inter­relation­ships between the atmo­spheric and land phases of…
  76. Hydrometer A device for measuring the specific gravity of fluids.
  77. Hydronic Heating Systems A type of heating system where water is heated in a boiler and either moves by natural convection or is pumped to heat exchangers or radiators in rooms…
  78. Hydrophilic Having a strong affinity (liking) for water. The opposite of hydrophobic.
  79. Hydrophobic Having a strong aversion (dislike) for water. The opposite of hydrophilic.
  80. hydrophobic interaction An interaction between a hydrophobic ('water-hating') part of a molecule and an aqueous environment.
  81. hydroponics The growing of plants without soil. Plants are fed with an aerated solution of nutrients, and the roots are either supported within an inert matrix, or…
  82. Hydropower The force of flowing water moving downstream creates energy that can be harnessed and turned into electricity.
  83. Hydrosphere The region that includes all the earth's liquid water, frozen water, floating ice, frozen upper layer of soil, and the small amounts of water vapor in the…
  84. Hydrostatic Relating to pressure or equilibrium of fluids. The pressures and forces resulting from the weight of a fluid at rest.
  85. Hydrostatic Head A measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure.
  86. Hydrostratigraphic Grouping of rock and sedimentary units based on the capacity of the rock, sediment, or soil to transmit water.
  87. Hydrothermal fluids These fluids can be either water or steam trapped in fractured or porous rocks; they are found from several hundred feet to several miles below the…
  88. Hydroxyapatite A natural mineral structure that contains calcium and phosphate ions that provide the power for the formation of bones and teeth.
  89. Hydro­meteorology An inter­disci­plinary science involving the study and analysis of the inter­relation­ships between the atmo­spheric and land phases of…
  90. Hyetograph A graphical representation of rainfall intensity with respect to time.
  91. Hygrometer An instrument which measures the humidity of the air.
  92. hygromycin An antibiotic used as selective agent in bacterial and transgenic plant cell cultures.
  93. Hygroscopic Absorbing or attracting moisture from the air.
  94. hygroscopic growth The rate that aerosol particles grow at relative humidity values less than 100 percent.
  95. Hyperconcentrated flow Moving mixture of sediment and water between 40 and 80 percent water by volume.
  96. hyperploid The situation in which a particular chromosome or chromosome segment is present in more than the normal number. Opposite: hypoploid.
  97. hypersensitive response 1. A specific reaction of a plant to attack by a pathogen. The plant cells surrounding the point of infection rapidly die and dry out, so that pathogen…
  98. hypersensitive site Regions in the DNA that are highly susceptible to digestion with restriction endonucleases.
  99. hypertonic A solution with an osmotic potential greater than that of living cells. Treatment with such solutions leads to the plasmolysis of cells.
  100. hypervariable region The parts of both the heavy and light chains of an antibody molecule that enable it to bind to a specific site on an antigen.