Outer Convective BandBands in a hurricane that occur in advance of main rain shield and up to 300 miles from the eye of the hurricane.
OutflowThe volume of growing cells that is removed from a bioreactor during a continuous fermentation process.
Outflow BoundaryA storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with passage…
Outflow ChannelA natural stream channel which transports reservoir releases.
OutgassingThe process by which materials expel or release gasses.
Outgoing Longwave RadiationOutgoing Longwave Radiation is a polar satellite derived measurement of the radiative character of energy radiated from the warmer earth surface to cooler…
OutletAn opening through which water can be freely discharged from a reservoir to the river for a particular purpose.
Outlet capacityThe amount of water that can be safely released through the outlet works.
Outlet channel (exit channel)Channel downstream from terminal structure that conveys releases back to the "natural" stream or river.
Outlet Discharge StructureProtects the downstream end of the outlet pipe from erosion and is often designed to slow down the velocity of released water to prevent erosion of the…
Outlet GateA gate controlling the flow of water through a reservoir outlet.
Outlet WorksA combination of structures and equipment required for the safe operation and control of water released from a reservoir to serve various purposes, i.e.
Outlet works towerA tower within a reservoir that contains the mechanisms to open the entrance to the outlet works.
OutlookUbiquitous Microsoft personal information management (PIM) program, which includes email, task management and a calendar.
Outside CoilThe heat-transfer (exchanger) component of a heat pump, located outdoors, from which heat is collected in the heating mode, or expelled in the cooling…
Ovarian follicleAn external, fluid-filled portion of the ovary in which oocytes mature before ovulation.
ovary(OH-vuh-ree) One of a pair of female reproductive glands in which the ova, or eggs, are formed.
OVCOvercast- An official sky cover classification for aviation weather observations, when the sky is completely covered by an obscuring phenomenon.
oven dry tonAn amount of wood that weighs 2000 lb at 0% moisture content.
Oven dry ton (ODT)An amount of wood that weighs 2,000 pounds at zero percent moisture content.
Overall safety of dams classificationOne of the following classifications is assigned to a dam following an onsite examination and subsequent analyses using available data and…
OverampingExceeding the rated capacity of a system.
Overbank depositsFine-grained sediment (silt and clay) deposited from suspension on a floodplain by floodwaters from a stream channel.
OverbreakMoving or loosening of rock as a result of a blast, beyond the intended line of cut.
OverburdenSoil or rock lying on top of a pay formation.
OvercastTo cast a lure, fly or bait beyond the aimed-for target.
overdominanceWhere heterozygote performance is superior to that of either parental genotype.
OverdraftWhen the amount of money withdrawn from a bank account is greater than the amount actually available in the account, the excess is known as an overdraft…
OverexcavationExcavation beyond specified or directed excavation. Removing unsuitable foundation material.
Overflow spillway (ogee spillway)A spillway that has a control weir that is ogee-shaped (S-shaped) in profile. A spillway on a dam that functions like a dam, but allows water to safely…
overlapping reading frameStart codons in different reading frames generate different polypeptides from the same DNA sequence.
Overlapping reading framesStart codons in different reading frames generate different polypeptides from the same DNA sequence. (See Reading frame.)
Overlay DistrictsZoning districts in which additional regulatory standards are superimposed on existing zoning.
OverloadTo exceed the design capacity of a device.
Overnight capital costThe capital cost of a project if it could be constructed overnight. This cost does not include the interest cost of funds used during construction.
OverrunningA weather pattern in which a relatively warm air mass is in motion above another air mass of greater density at the surface.
Overshooting Top(or Penetrating Top) - A dome-like protrusion above a thunderstorm anvil, representing a very strong updraft and hence a higher potential for severe…
OverstoryThe portion of the trees forming the upper or uppermost canopy in a forest stand.
OvertoppingFlow of water over the top of a dam or embankment.
OverturnThe almost spontaneous mixing of all layers of water in a reservoir or lake when the water temperature becomes similar from top to bottom.
OverwindingA rope or cable wound and attached so that it stretches from the top of a drum to the load.
OviductThe passage through which the ova travel from the ovary into the uterus.
OvonicA device that converts heat or sunlight directly to electricity, invented by Standford Ovshinsky, that has a unique glass composition that changes from an…
ovum pickup(Abbreviation: OPU). The non-surgical collection of ova from a female.
Oxbow channelA natural U-shaped channel in a river as viewed from above.
oxidative phosphorylationThe enzymatic addition of a phosphate to ADP to make ATP, coupled to electron transport from a substrate to molecular oxygen.
OxidizeTo chemically transform a substance by combining it with oxygen.
Oxygen cycleCyclic movement of oxygen in different chemical forms from the environment, to organisms, and then back to the environment.
oxygen isotope ratio (δ<sup>18</sup>O)an expression for the ratio of the two isotopes 18O to 16O in a sample relative to a standard, defined as: δ18O= (18O/16Osample - 18O/16Ostandard)/…
oxygen-electrode-based sensorSensor in which an oxygen electrode, which measures the amount of oxygen in a solution, is coated with a biological material such as an enzyme which…
OxygenateA cleaner-burning additive in a fuel—usually containing hydrogen, carbon, and oxygen. Examples are ethers and alchohols, such as ethanol and methanol.
Oxygenated FuelsFuels blended with an additive—usually ether or ethanol—to increase oxygen content, allowing more-thorough combustion for reduced carbon monoxide…
OxygenatesGasoline fuel additives such as ethanol, ETBE, or MTBE that add extra oxygen to gasoline to reduce carbon monoxide pollution produced by vehicles.
OzonationThe application of ozone to water for disinfection or for taste and odor control.
OzoneTropospheric ozone (ground-level ozone), or smog, is formed when volatile organic compounds, oxygen and nitrogen oxides react in the presence of sunlight.
Ozone (O3)A strong-smelling, reactive, toxic, chemical gas consisting of three oxygen atoms chemically attached to each other.
Ozone (O<sub>3</sub>)A colorless gas with a pungent odor, having the molecular form of O3 , found in two layers of the atmosphere, the stratosphere (about 90% of the total…
Ozone Action DayA "heads-up" message issued by the Department of Natural Resources (DNR) through the National Weather Service when ozone levels may reach dangerous levels…
Ozone AdvisoryIt is issued by the Department of Natural Resources (DNR) through the National Weather Service when ozone levels reach 100.
Ozone Depleting Substance (ODS)A family of man-made compounds that includes, but are not limited to, chlorofluorocarbons (CFCs), bromofluorocarbons (halons), methyl chloroform, carbon…
Ozone HoleA severe depletion of stratospheric ozone over Antarctica that occurs each spring. The possibility exists that a hole could form over the Arctic as well.
Ozone LayerAn atmospheric layer that contains a high proportion of oxygen that exists as ozone.
Ozone PrecursorsChemical compounds, such as carbon monoxide, methane, non-methane hydrocarbons, and nitrogen oxides, which in the presence of solar radiation react with…
Ozone shieldOzone shield Stratospheric ozone layer, giving protection to the Earth's surface due to intense absorption of harmful solar ultraviolet radiation by the…