Science terms starting with P

1,062 terms

  1. Public Utility Holding Company Act (PUHCA) of 1935 A law to protect consumers and investors. It placed geographic restrictions on mergers and limitations on diversification into non-utility lines of…
  2. Public Utility or Services Commissions (PUC or PSC) These are state government agencies responsible for the regulation of public utilities within a state or region.
  3. Public Utility Regulatory Policies Act (PURPA) A federal law requiring a utility to buy the power produced by a qualifying facility at a price equal to that which the utility would otherwise pay if it…
  4. Publications Books, manuals, and publications of the Bureau of Reclamation may be obtained from the National Technical Information Service (NTIS), U.S.
  5. Publicly Owned Treatment Works Permit (POTW) A permit that regulates discharges to publicly owned sewage treatment plants.
  6. Publics Any interested group or individual, including Federal, State and local agencies, interest groups, ad hoc groups, and the general public.
  7. PUC A widely used expression plasmid containing a -galactosidase gene. (See Plasmid.)
  8. Puddle To compact loose soil by soaking it and allowing it to dry.
  9. Puddling A method of compacting soil with the soil deposited into a pool of water and then stirred or rodded.
  10. Pueblo The Spanish word for town. A community dwelling with numerous households within, up to five stories high, built of stone or adobe by Indian tribes in the…
  11. Pueblo rights A water right possessed by a municipality which, as a successor of a Spanish or Mexican pueblo, entitled to the beneficial use of all needed…
  12. Puget Sound Convergence Zone A situation where wind forced around the Olympic Mountains converges over the Puget Sound.
  13. Pull shovel (dragshovel or hoe) A shovel with a hinge-and-stick mounted bucket that digs while being pulled inward.
  14. Pulp chips Timber or residues processed into small pieces of wood of more or less uniform dimensions with minimal amounts of bark.
  15. Pulse A short burst of electromagnetic energy that a radar sends out in a straight line to detect a precipitation target.
  16. Pulse Duration The time over which a radar pulse lasts. The pulse duration can be multiplied by the speed of light to determine the pulse length or pulse width.
  17. Pulse Length The linear distance in range occupied by an individual pulse from a radar. h = c * t , where t is the duration of the transmitted pulse, c is the speed of…
  18. Pulse Radar A type of radar, designed to facilitate range (distance) measurements, in which are transmitted energy emitted in periodic, brief transmission.
  19. Pulse Repetition Frequency (PRF) The amount of time between successive pulses, or bursts, of electromagnetic energy that is transmitted by a radar.
  20. Pulse Repetition Time (PRT) The time elapsed between pulses by the radar. This is also called the pulse interval.
  21. Pulse Resolution Volume A discrete radar sampling volume, of dimensions (horizontal beamwidth * vertical beamwidth * 1 range gate).
  22. Pulse Severe Thunderstorms Single cell thunderstorms which produce brief periods of severe weather (3/4 inch hail, wind gusts in the excess of 58 miles an hour, or a tornado).
  23. Pulse Storm A thunderstorm within which a brief period (pulse) of strong updraft occurs, during and immediately after which the storm produces a short episode of…
  24. Pulse Width Same as Pulse Length; the linear distance in range occupied by an individual pulse from a radar.
  25. Pulse-Pair Processing Nickname for the technique of mean velocity estimation by calculation of the signal complex covariance argument.
  26. Pulse-Width-Modulated (PWM) Wave Inverter A type of power inverter that produce a high quality (nearly sinusoidal) voltage, at minimum current harmonics.
  27. pulsed-field gel electrophoresis (Abbreviation: PFGE). A procedure used to separate very large (50 kbp to several Mbp) DNA molecules by alteRNA ting the direction of electric current in a…
  28. Pump See centrifugal pump, diaphragm pump, jetting pump.
  29. Pump Octane Number This number represents the ability of a fuel to resist knocking when ignited in the cylinder of an internal-combustion engine.
  30. Pump-back system A return-flow system in which tailwater is pumped back to the head of an irrigation ditch for reuse.
  31. Pumped Storage Facility A type of power generating facility that pumps water to a storage reservoir during off-peak periods, and uses the stored water (by allowing it to fall…
  32. Pumped-storage plant Powerplant designed to generate electric energy for peakload use by releasing water previously pumped into an elevated storage reservoir, usually during…
  33. Pumping Mechanical transfer of fluids.
  34. Pumping energy Energy required to pump water from the lower reservoir to the upper reservoir of a pumped-storage plant.
  35. Pumping Head Energy given to a fluid by a pump, usually expressed in feet of fluid (foot pounds per pound).
  36. Pumping plant Facility that lifts water up and over hills.
  37. Pumplift (pumping lift) The vertical distance that a pump will raise waters. Distance water must be lifted in a well from the pumping level to the ground surface.
  38. punctuated equilibrium The occurrence of speciation events in bursts, separated by long intervals of species stability.
  39. Purchase of Development Rights Programs through which local governments may purchase development rights and dedicate the land for conservation easements, protecting it as open space or…
  40. Purchased power Normally this type is used to represent the purchase cost of energy for firming up the power supply.
  41. pure line A strain in which all members are genetically nearly identical and are indistinguishable by phenotype.
  42. purification tag See: affinity tag.
  43. Purine A double-ring, nitrogen-containing base present in nucleic acids . Adenine (A) and guanine (G) are the two purines normally present in DNA and RNA…
  44. Purveyor An agency or person that supplies water.
  45. PVA The Plant Variety Act. See U.S. Department of Agriculture.
  46. PVL Prevail
  47. PvP Player vs. Player. This means for one player to attack another player.
  48. PVR Abbreviation for plant variety rights.
  49. pW Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column…
  50. PWAT Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column…
  51. PWO Public Severe Weather Outlook
  52. PWP Abbreviation for permanent wilting point.
  53. Pyranometer A device used to measure total incident solar radiation (direct beam, diffuse, and reflected radiation) per unit time per unit area.
  54. pyrethrins Active constituents of pyrethrum (Tanacetum cinerariifolium) flowers, used as insecticides.
  55. Pyrheliometer A device that measures the intensity of direct beam solar radiation.
  56. Pyrimidine A single-ring, nitrogen-containing base present in nucleic acid s. Cytosine (C) and thymine (T) are present in DNA, whereas uracil (U) replaces T in RNA.
  57. Pyroclastic Ash mixed with larger igneous rock fragments produced by explosive volcanic eruptions.
  58. Pyroclastic flow High-speed avalanches of hot ash, rock fragments, and gas that move down the sides of a volcano during explosive eruptions or when the steep edge of a…
  59. Pyroclastic surge Similar to a pyroclastic flow, but contains a higher proportion of gas to rock and is more turbulent and faster moving.
  60. pyrogen Bacterial substance that causes fever in mammals.
  61. Pyrolysis The transformation on a compound or material into one or more substances by heat alone (without oxidation). Often called destructive distillation.
  62. pyrophosphate A phosphate ion dimer; may be released on hydrolysis of ATP.