Science terms starting with U

164 terms

101. Unvented Heater A combustion heating appliance that vents the combustion by-products directly into the heated space.
102. Unwatering As opposed to dewatering, unwatering is the interception and removal of ground water outside of excavations and the removal of ponded or flowing surface…
103. Up-valley Wind A diurnal thermally driven flow directed up a valley's axis, usually occurring during daytime; part of the along-valley wind system.
104. Updraft A small-scale current of rising air. If the air is sufficiently moist, then the moisture condenses to become a cumulus cloud or an individual tower of a…
105. Upland The portion of the landscape above the valley floor or stream.
106. Uplift Charges from an RTO/ISO collected outside of the market-clearing commodity price; these charges can include payments to reliability must run (RMR) units…
107. Uplift pressure See pore-water pressure.
108. Uplighting Light directed upward at greater than 90° above nadir, generally upward into the sky.
109. Upper air observation Upper air observation An observation made in the free atmosphere either directly or indirectly.
110. Upper atmosphere Upper atmosphere The general term applied to the atmosphere above the mesopause.
111. Upper Level In weather observing, the term applies to the portion of the atmosphere that is above the lower troposphere, generally 850 hPa and above.
112. Upper Level Disturbance A disturbance in the upper atmospheric flow pattern which is usually associated with clouds and precipitation.
113. Upper Level System A general term for any large-scale or mesoscale disturbance capable of producing upward motion (lift) in the middle or upper parts of the atmosphere.
114. Upper-air sounding An upper-air observation of the vertical profile of an atmospheric variable such as temperature or wind.
115. Upper-air Weather Chart Weather maps that are produced for the portion of the atmosphere above the lower troposphere, generally at and above 850 mb.
116. UPR Utility, Plant, and Reissue -- see patent for more
117. Uprate An increase of greater than 15 percent in powerplant unit output at an existing facility through modifications or replacement of equipment.
118. Upslope Flow Same as Orographic Lifting; air that flows toward higher terrain, and hence is forced to rise.
119. Upslope Fog A fog that forms when moist, stable air is carried up a mountain slope.
120. UPSLP Upslope
121. upstream The region extending in a 5' direction from a gene.
122. Upstream Blanket An impervious blanket placed on the reservoir floor and abutments upstream of a dam.
123. Upstream face The inclined surface of the dam that is in contact with the reservoir. See face.
124. upstream processing See: upstream (2).
125. Upstream Slope The part of the dam which is in contact with the reservoir water. On earthen dams, this slope must be protected from the erosive action of waves by rock…
126. UPSTRM Upstream
127. Upwarp A broad anticline with gently sloping limbs formed as a result of differential uplift.
128. Upwelling In ocean dynamics, the upward motion of sub-surface water toward the surface of the ocean. This is often a source of cold, nutrient-rich water.
129. upwelling longwave irradiance The rate at which radiant energy, at a wavelength longer than approximately 4 µm, is being emitted upwards into a radiation field and transferred across…
130. upwelling shortwave radiance The rate at which radiant energy, at a wavelength between 0.4 and 4 µm, is being emitted upwards into a radiation field and transferred across a surface…
131. Upzone To change the zoning of a tract or parcel of land from a lesser to greater intensity of usage.
132. uracil (YOOR-uh-sil) One of four building blocks of ribonucleic acid (RNA), a type of nucleic acid found in all cells.
133. Urban and Small Stream Flood Advisory This advisory alerts the public to flooding which is generally only an inconvenience (not life-threatening) to those living in the affected area.
134. Urban and Small Stream Flooding Flooding of small streams, streets, and low-lying areas, such as railroad underpasses and urban storm drains.
135. Urban area Predominantly cities, towns or developed areas where the population is significant.
136. Urban Flash Flood Guidance A specific type of flash flood guidance which estimates the average amount of rain needed over an urban area during a specified period of time to initiate…
137. Urban Flooding Flooding of streets, underpasses, low lying areas, or storm drains. This type of flooding is mainly an inconvenience and is generally not life threatening.
138. Urban Growth Boundary A line drawn around a city that prohibits development outside that boundary. Designed to slow or prevent sprawl, UGBs are designed to accommodate growth…
139. Urban Heat Island The increased air temperatures in urban areas in contrast to cooler surrounding rural areas.
140. Urbanization To become urban in nature or character; residential, commercial, and industrial development.
141. uridine The (ribo)nucleoside resulting from the combination of the base uracil (U) and the sugar D-ribose. See: uridylic acid, uridine triphosphate.
142. uridine triphosphate (uridine 5'-triphosphate) (Abbreviation: UTP). Required for RNA synthesis since it is a direct precursor molecule. See: uridylic acid.
143. uridylic acid Synonym for uridine 5'-monophosphate (abbreviation: UMP), a (ribo)nucleotide containing the base uracil. See: uridine triphosphate.
144. uronic acid A simple sugar whose terminal -CH2OH group has been oxidized to an acid, COOH group.
145. Usable storage capacity The quantity of ground water of acceptable quality that can be economically withdrawn from storage.
146. Usage charge A charge levied on power suppliers or their customers for the use of transmission or distribution lines and facilities.
147. USDA See The U.S. Department of Agriculture.
148. Use value The economic benefit associated with the physical use of a resource, usually measured by the consumer surplus or net economic value associated with such…
149. Use Value Taxation Land assessments according to the value of the present use rather than the speculative value.
150. Useful Heat Heat stored above room temperature (in a solar heating system).
151. User day The participation in a recreation activity at a given resource during a 24-hour period by one person.
152. User fee A fee which is collected only from those persons who use a particular service, as opposed to one collected from the public in general.
153. USGS United States Geological Survey.
154. USGS (United States Geological Survey) A federal agency which provides mapping of topography, aquifer levels, and areas where aquifers are recharged.
155. UTC By international agreement, the local time at the prime meridian, which passes through Greenwich, England.
156. Uterine Pertaining to the uterus.
157. Utility See Useful.
158. Utility scale facilities Facilities that generate large amounts of electricity that is delivered to many users through transmission and distribution systems.
159. utilization of farm animal genetic resources The use and development of animal genetic resources for the production of food in a sustainable system of agriculture.
160. UTP See: uridine triphosphate.
161. UV Index Ultraviolet Index- This index provides important information to help you plan your outdoor activities in ways that prevent overexposure to the sun's rays.
162. UVM Upward Vertical Motion (also known as Upward Vertical Velocity)
163. UVV Upward Vertical Velocity (rising air)
164. UWNDS Upper Winds