A  TERMS

Abiogenic - Not produced by the action of living organisms. 

Abiotic - Non-living, e.g., the abiotic environment is the nonliving, physical portion of the environment such as rock, soil (excluding microbes), water, and air. 

Absolute Humidity - the mass (in grams) of water in a volume (cubic meter) of air; units are g/m3. 

Absorption - when the substance of interest is captured by another substance, reducing the amount available. For examble, solar energy is absorbed by some atmospheric molecules, solar collectors, and the ocean. 

Aerosol - excluding weather and clouds, any small particle that tends to stay in the air, such as smoke, dust, salt, and pollen. 

Aerosol Optical Depth - (technically known as the relative aerosol optical depth) usually considered to be synonymous with the airmass, is the approximate number of aerosols in a path through the atmosphere relative to the standard number of aerosols in a vertical path through a clean, dry atmosphere at sea level. 

AES - Atmospheric Environment Service, the Canadian equivalent of USA's National Oceanic and Atmospheric Administration. AES operates the solar measurement network for Canada. They are also the equivalent of USA's National Climatic Data Center in that they respond to requests for weather data and maintain the data archives. 

AHF - Automatic Hickey-Frieden absolute cavity radiometer. This is the model designation given by The Eppley Laboratory, Inc. for their commercial version of an electrically self-calibrating absolute cavity radiometer used to define and transfer the World Radiometric Reference (WRR) to pyrheliometers and pyranometers used for solar irradiance measurements. The WRR is maintained at the World Radiation Center, Davos, Switzerland for the World Meteorological Organization. 

Airmass - the relative path length of the direct solar beam radiance through the atmosphere. When the sun is directly above a sea-level location the path length is defined as airmass 1 (AM 1.0). AM 1.0 is not synonymous with solar noon because the sun is usually not directly overhead at solar noon in most seasons and locations. When the angle of the sun from zenith (directly overhead) increases, the airmass increases approximately by the secant of the zenith angle

Air pollution: Air is the ocean we breathe. Air supplies us with oxygen which is essential for our bodies to live. Air is 99.9% nitrogen, oxygen, water vapor and inert gases. Human activities can release substances into the air, some of which can cause problems for humans, plants, and animals. There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include smog, acid rain, the greenhouse effect, and "holes" in the ozone layer. Each of these problems has serious implications for our health and well-being as well as for the whole environment. 

airborne radioactivity:
Radioactive material in any chemical or physical form that is dissolved, mixed, suspended, or otherwise entrained in air.

airborne radioactivity area:
Any area where the concentration of airborne radioactivity, above natural background, exceeds or is likely to exceed 10 percent of the derived air concentration (DAC) values. DAC values are contained in Appendices A and C of 10 CFR 835.

AFUE 
The AFUE, or Annualized Fuel Utilization Efficiency, is the ratio of the total useful heat your gas furnace delivers to your house to the heat value of the fuel it consumes.

annual limit on intake (ALI): 
The derived limit for the amount of radioactive material taken into the body of an adult worker by inhalation or ingestion in a year. ALI is the smaller value of intake of a given radionuclide in a year by the reference man (ICRP Publication 23) that would result in a committed effective dose equivalent of 5 rems (0.05 sievert) or a committed dose equivalent of 50 rems (0.5 sievert) to any individual organ or tissue.

As Low As Reasonably Achievable (ALARA): 
An approach to radiological control to manage and control exposures (individual and collective) to the work force and to the general public at levels as low as is reasonable, taking into account social, technical, economic, practical and public policy considerations. As used in this Manual, ALARA is not a dose limit but a process that has the objective of attaining doses as far below the applicable controlling limits as is reasonably achievable.

ALARA Committee: 
Multidisciplined forum that reviews and advises management on improving progress toward minimizing radiation exposure and radiological releases.

assessment: 
Evaluation or appraisal of a process, program or activity to estimate its acceptability

Asbestos - Group of naturally occurring minerals that separate into fibers. The asbestos family includes actinolite, anthophyllite, chrysotile, crocidolite and tremolite. 

Azimuth
An angle measured clockwise relative to some
reference point on a circle (e.g., "south" or "north"). 

B TERMS

background radiation: 
Radiation from: 

Naturally occurring radioactive materials which have not been technologically enhanced; 

Cosmic sources; 

Global fallout as it exists in the environment (such as from the testing of nuclear explosive devices); 

Radon and its progeny in concentrations or levels existing in buildings or the environment which have not been elevated as a result of current or prior activities; and 

Consumer products containing nominal amounts of radioactive material or producing nominal amounts of radiation. 

becquerel (Bq): 
The International System (SI) unit for activity of radioactive material. One becquerel is that quantity of radioactive material in which one atom is transformed per second or undergoes one disintegration per second.

Biomass - Literally, "living weight", refers to mass having its origin as living organisms (i.e., plants or animals). 

Biome - Recognizable community units formed by the interaction of regional climate, regional biota, and substrate. (e.g., The same biome units generally can be found on different continents at the same latitudes that produce about the same weather conditions and where topography is similar. Biomes are the largest land community units recognized. 

Biota - Living organisms including plants and animals 

Blackwater Draw Formation - Quaternary formation consisting primarily of pedogenically modified eolian sands and silts interbedded with numerous caliche layers. The Blackwater Draw Formation overlies the Tertiary Ogallala Formation at Pantex. 

Booster - The final high-explosive component of an explosive train that amplifies the detonation from the lead or detonator. Thus, a booster charge reliably detonates the main high-explosive charge of the munition

bioassay: 
The determination of the kinds, quantities, or concentrations, and, in some cases, locations of radioactive material in the human body, whether by direct measurement or by analysis and evaluation of radioactive materials excreted or removed from the human body.

Btu 
Btu, short for British Thermal Unit is a unit of heat energy. One Btu is the amount of heat needed to raise the temperature of one pound of water 1°F. To get a rough idea of how much heat energy this is, the heat given off by burning one wooden kitchen match is approximately one Btu. 

C  TERMS

C-weighting - Similar to A-weighting but with less discrimination against low-frequency sound. Appropriately used in measurement of high-level sounds and impulsive sounds. 

Calcic - derived from or containing calcium or lime. 

Calcrete - a conglomerate consisting of surficial sand and gravel cemented into a hard mass by calcium carbonate precipitated from solution by infiltrating waters or deposited by the escape of carbon dioxide from vadose water. 

Caliche - gravel, sand or desert debris cemented by porous calcium carbonate; also the calcium carbonate itself. Found in Mexico and Southwest U.S. Calcium carbonate precipitated as surface or near-surface crusts by the evaporation of moisture in the pore spaces of soils

Cellulose 
Cellulose insulation is made from wastepaper, such as used newspaper and boxes. It is shredded into small particles, and chemicals providing resistance to fire and insects are added. Cellulose insulation is dusty and brown, with flat particles, on which you can frequently find legible print.

COP
Coefficient of Performance, COP, is the ratio of energy input to heating capacity. This is the instantaneous measurement of the heating performance of your heat pump. It is comparable to knowing how many miles per gallon of gasoline your car gets when it is going full speed. You can find the COP on the nameplate of your heat pump.

Conduction
The transfer of heat through a solid material. 

Convection
The transfer of heat by air flow. 
 

D TERMS

Day-night sound exposure (Total) - The sound exposure for a 24-hour calendar day calculated by adding the sound exposure obtained during the daytime (0700-2200 hours) to ten times the sound exposure obtained during the nighttime (0000-0700 and 2200-2400 hours). The frequency weighting shall be stated; otherwise, the A-weighting will be understood. Unit: pascal-squared second (PA2 s). 

Day-night sound exposure level (Total) - Ten times the common logarithm of the ratio of the (total ) day-night sound exposure to the reference sound exposure (E0) of 400 micropascals-squared seconds (400 mPa2 s). Unit decibel (dB). 

Declassification - The act of making a weapon component unclassified through destruction or modification. 

Demilitarization - A process or procedure that renders an item unusable for its original weapon purpose. 

Design Agency - A DOE contractor responsible for the design of a DOE weapon and weapon-related material and the integrity of the design through stockpile life. 

Diagnostic Artifact - Any object manufactured or modified by human beings that is also unique to a particular period or cultural manifestation in prehistory or history. 

Diatomaceous Earth - A light, friable, siliceous material derived chiefly from diatom remains and used especially as a filter. 

Diurnal - daily, or the daily cycle- A diurnal plot is usually a representative midnight-to-midnight graph of values measured at a smaller time interval (e.g., hourly or 5-minute values). 

DOE - in this context, always refers to the United States Department of Energy, although other departments may have the same acronym. 

Dry-bulb Temperature - air temperature measured with a thermometer, similar to ambient temperature. The term "dry-bulb" distinguishes it from the wet-bulb temperature measured by a psychrometer to determine relative humidity. 
 

E TERMS

Electromagnetic Radiation - the energy produced by an oscillating electrical (and magnetic) field, transmitted by photons. See Electromagnetic Spectrum. 

Electromagnetic Spectrum - the entire energy range of electromagnetic radiation specified by frequency, wavelength, or photon energy. The low end of the spectrum is infrared radiation (heat), and passes through the colors of visual light from red through violet, through ultraviolet radiation, x-rays, and gamma rays. Radio and television are transmitted on specific electromagnetic frequencies. 

Emissivity - the ratio of the actual amount of electromagnetic radiation emitted by an object to the amount emitted by an ideal blackbody at the same temperature. 

Energy - the ability to do work. Some units of energy, such as foot-pounds, measure the ability to lift a weight a certain height, units, such as calorie, indicate the ability to increase temperature, while units of radiation are usually the frequencies or wavelengths of photons. 

Environment Canada - Environment Canada is the federal coordinating agency for all environmental issues pertaining to Canada. 

EPRI - the Electric Power Research Institute, a research consortium of electric power companies in the United States. 

Equation of Time - the annual East-West swing of the location of the Sun which can be detected by noting the position of the Sun at the same time (such as noon) each day. This motion is caused by the libration (wobble) of the Earth and can be estimated by (Spencer, J. W. (1971). Fourier series representation of the position of the Sun. Search 2 (5), 172 ) : 
  ET = 229.18 x ( 0.000075 + 0.001868 cos D - 0.032077 sin D - 

      0.014615 cos 2D - 0.040849 sin 2D ) 

where 

  D = nD ( 360° / 365 ) 

and nD is the number of the day (e.g., Feb. 1 makes nD = 32). 

NREL uses solar position algorithms that do not require the equation of time (Michalsky, J. J. (1988). The Astronomical Almanac's algorithm for approximate solar position (1950-2050). Solar Energy 40 (3), 227-235 ) . 

Equinox - literally "equal night", a day when the number of hours of daylight equals the number of hours of night. The vernal equinox, usually March 21, signals the onset of Spring, while the autumnal equinox, usually September 21, signals the onset of Autumn. 

Erg - a metric unit of energy (dyne-cm). A joule is 100,000 ergs. 

ERSATZ - literally "inferior substitute", the 222 measurement sites in the 1952-1975 SOLMET/ERSATZ solar & meteorological hourly network that did not measure solar radiation. The solar radiation for these sites was modeled from cloud cover data and other information. The SOLMET/ERSATZ network has been replaced by the 1961-1990 National Solar Radiation Data Base. 

ETR - extraterrestrial radiation, also known as "top-of-atmosphere" (TOA) irradiance, is the amount of global horizontal radiation that a location on Earth would receive if there was no atmosphere or clouds (i.e., in outer space). This number is used as the reference amount against which actual solar energy measurements are compared. 

Evaporation - the process of converting a substance (such as water) from its liquid phase to its gaseous phase. 

Extraterrestrial Radiation - abbreviated ETR, also known as "top-of-atmosphere" (TOA) irradiance, is the amount of global horizontal radiation that a location on Earth would receive if there was no atmosphere or clouds (i.e., in outer space). This number is used as the reference amount against which actual solar energy measurements are compared. 
 

F TERMS

Farenheit Scale - the English temperature scale for which 32°C is the temperature at which water freezes and 212°C is the temperature at which water boils, at standard atmospheric pressure. The conversion from Celsius to Farenheit is 
    F = 1.8 C + 32 

F-CHART - a solar power system analysis and design program. For more information, see the F-CHART home page. 

Fixed-Tilt Array - a set (array) of solar power collectors that do not pivot to follow the track of the Sun in the sky. In the Northern Hemisphere, they are usually mounted with a southern tilt that will maximize the amount of energy that they can receive. 

Flat-Plate Collector - a solar power collector that absorbs the Sun's energy on a flat surface without concentrating or refocusing it. 

Flux - the rate at which a substance flows. The Watt is a unit of energy flux, because it indicates the amount of energy (in joules) that flows every second. 

Focusing Collector - a collector that enhances solar energy by focusing it onto a smaller area through mirrored surfaces or lenses. 

G TERMS

Gigawatt - 1,000,000,000 (or 109) Watts. This unit rose to public prominence in the 1985 motion picture Back to the Future in which 1.21 gigawatts of power were required for the time-travelling vehicle. 

Global Horizontal Radiation - total solar radiation; the sum of direct, diffuse, and ground-reflected radiation; however, because ground reflected radiation is usually insignificant compared to direct and diffuse, for all practical purposes global radiation is said to be the sum of direct and diffuse radiation only. 

Greenhouse Effect - the warming of the Earth by the atmosphere because of water vapor and gases such as carbon dioxide, which absorb and emit infrared radiation, or heat. Thus, the high-energy photons such as light and ultraviolet radiation are passed through the atmosphere to the Earth, which tends to absorb them and emit lower-energy photons which are then captured in the atmosphere and partially sent back to Earth. As the presence of infrared absorbers rises in the atmosphere, the more solar energy is retained at heat in the atmosphere and on the surface of the Earth. Because glass also passes light and tends to absorb and reflect heat, this effect is compared to that of a greenhouse. 

Ground-Reflected Radiation - the radiation from the sun which is reflected back into the atmosphere after striking the Earth. 

R TERMS

Radiant barrier 
Radiant barriers are thin sheets of highly reflective material, like aluminum, which reduce heat transfer from thermal radiation across the air space between the roof and the attic floor. Radiant barrier do nothing to prevent heat transfer by conduction or convection. An excellent website covering radiant barriers is the Department of Energy's Radiant Barrier Fact Sheet, produced by Oak Ridge National Laboratory.

R-Value
R-value is a measurement of heat resistance. It is the inverse of the U-value, so the higher the R-value the better the insulation resists heat transfer. Many factors can affect the R-value of insulation, including the type of insulation, and the age of the insulation. To determine the R-value of the insulation in your house, first determine the type of insulation present, whether that insulation is new, and measure the depth of the insulation in inches. Look your insulation up on the table below, and multiply the R-value per inch by the number of inches present in your house.

Radiation 
The transfer of heat directly from one surface to another (whithout the intermediate air acting as a transfer mechanism). 

Rigid Boards
Rigid boards are fibrous materials or plastic foams pressed or extruded into board-like forms. These provide thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths. 

Recovery efficiency
How efficiently heat from the heat source is transferred to the water. 

Rockwool 
Dirty grey, although the color can range through green and brown as well. Rockwool looks like old wool with dark flecks, and you can often find what looks like sand or small pebbles underneath the insulation. Rockwool is spun, like fiberglass, from the slag from refining metals. The debris that settles underneath the insulation is remnants of the slag, and condensed droplets of metal. 

S TERMS

Solar Cycle. Activity on the Sun varies with a period, on average, of 11 years. The solar cycle is most evident through the number of sunspots present on the solar disk. At the start of new cycle there will be no or very few spots. Those that are present will be at high heliographic latitudes. As the cycle progresses, the number of spots increase and the latitude at which these spots appear reduces. The solar maximum will occur typically 3 to 5 years after solar minimum. The decline to minimum is longer than the rise to maximum. Sunspots with the largest areas tend to occur in the two years after solar maximum. At the end of the cycle, sunspots can be found close to the solar equator (together with high latitude spots from the new cycle).

Solar Rotation. The mean sidereal rotation period is 25.38 days (the Carrington period). The corresponding synodic rotation period is 27.2753 days. The sidereal period is the rotation period as viewed from a fixed point in space whereas the synodic period is the rotation period as viewed from Earth (and thus is used when calculating heliographic coordinates).