Glossary

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Glossary

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absolute zero:

the lowest possible temperature, O K = -273^oC O K = -460^oF

acid deposition:

adding sulfuric or nitric acid to the environment by rain, snow, or dry sediment.

active solar heating:

heating a house by using a solar collector with pumps or fans to transfer the heat into the house.

aerosols:

solid or liquid matter in the atmosphere, usually smaller than 10 microns.Aerosols may be breathed deeply into the lungs, causing lung damage.

alcohol fuel:

fuel made by distilling grain, wood, or other plant products into alcohol.

alpha ray:

the nucleus of a helium atom consisting of two protons and two neutrons.

altitude angle:

elevation or angle of the sun above the horizon. Altitude plus azimuth angles completely determine the sun's position in the sky.

ampere:

the unit of measurement of electric current. One ampere is a flow of one coulomb of charge per second.

anaerobic digestion:

decomposition process by which bacteria convert organic material into methane in the absence of oxygen.

atomic number:

the number of protons in the nucleus. This is also equal to the number of electrons in a neutral atom.

available energy:

the maximum amount of work that can be extracted in a particular process.

avoided cost:

cost to a utility of adding new electrical capacity, expressed in cents per kwh.

azimuth angle:

angle of the sun from true south. Azimuth plus altitude angles completely determine the sun's position in the sky.

beta ray:

a positive or negative electron; a natural component of radioactivity.

binding energy:

the energy that holds a nucleus together; the difference between the sum of the masses of the individual nucleons and the actual mass of the nucleus.

Biomass:

organic material in any form: wood, crop residue, animal manure, and so forth.Biomass contains energy stored in chemical form.

Breeding:

the process whereby a fissile nucleus is produced from a nonfissile nucleus in a reactor by neutron absorption.

British Thermal Unit (Btu):

the energy required to raise the temperature of one pound of water by 1 degree Fahrenheit.

BWR:

boiling water reactor; a nuclear reactor in which the reactor water is allowed to boil to produce steam.

Carnot efficiency:

maximum efficiency for converting heat energy into work; given by (1 - T_c/T_h), with the temperatures in absolute units.

Caulking:

a soft material that can be squeezed into the cracks of a building to reduce the air flow into or out of the building.

CFC (chlorofluorocarbons):

production of both electricity and useful heat from the same fuel source.

Conduction:

the process by which heat travels through substances.

Convection:

the process by which heat is transferred by the movement of fluids.

COP (coefficient of performance):

ratio of heat transferred by a heat pump to its electricity input.

COP maximum:

the maximum value of COP allowed by the Second Law of Thermodynamics.

cross-section:

probability for a nuclear reaction to occur.

Curie:

a measure of activity; 1 Ci = 3.7 x 10¹⁰ disintegrations per second.

Darrieus rotor:

a vertical egg-beater-type wind turbine machine.

degree days (DD):

the difference between the mean daily temperature and 65^oF.Degree days are cumulative over any period of time. The heat lost from a house is proportional to degree days.

DHW:

domestic hot water.

diffuse radiation:

solar radiation received under cloudy skies; cannot be focused by mirrors or lenses.

direct radiation:

solar radiation received under clear skies. Can be focused.

doubling time:

the time required for a given quantity to double in value; approximately, DT = 70 years/% growth rate.

Demand Side Management (DSM):

utility programs used to reduce peak electrical demand and increase efficiency.

ECCS (emergency core cooling system):

a high-pressure water spray system that is used to cool the reactor core in the event of a loss of coolant accident.

Efficiency:

the ratio of the useful work output to the total energy input or energy converted.

Electrolyte:

a chemical that, when dissolved in water, will conduct an electrical current.

electrostatic precipitator:

a device for removing particulates from the combustion gases in a power plant.

EMF:

electromagnetic field, usually used in association with high voltage electrical transmission lines.

Emissivity:

measure of a material's ability to give off thermal radiation.

Enrichment:

the process in which the abundance of the fissile isotope, ²³⁵U, is increased from 0.7% to 2-3% in the uranium oxide fuel.

Entropy:

a term used in thermodynamics to measure the disorder of a system. Entropy always increases when energy is converted in an isolated system. The net entropy always increases for a system and its surroundings (environment).

Eutrophication:

enrichment of a body of water by the addition of extra nutrients, stimulating algae growth. Nitrogen and phosphorus are two common nutrients added to lakes.

eV (electron volt):

an amount of energy equal to 1.6 x 10^-19 joules.

exponential growth:

a process in which the amount of a substance has a fixed growth rate, or the change in amount of something is proportional to the amount present.

fertile material:

nuclei that do not fission but can be used to create fissionable nuclei through neutron absorption -- e.g., ²³⁸U.

first law:

conservation of energy in a thermodynamic system; the heat added + work done = the change in the total energy of a system.

fissile material:

nuclei that will undergo fission when a neutron is absorbed, e.g., ²³⁵U, ²³⁹Pu.

fission products:

process to remove SO₂ from exhaust gases in a power plant.

fluidized bed combustion:

device that produces electricity from a chemical reaction between hydrogen and oxygen.

Fusion:

the process of bringing two nuclei together to form one nucleus; energy is released through the loss of mass in the product nucleus.

gamma ray:

a high energy photon of electromagnetic energy released in some radioactive decays.

gas turbine:

a heat engine that produces electricity by using the force of hot, expanding gases to make a turbine revolve. The gases are produced by burning a fuel.

gaseous diffusion:

the enrichment of ²³⁵U by diffusion of uranium hexafluoride gas through porous barriers.

Generator:

a device that changes mechanical energy into electrical energy. It consists of a magnet and a coil of wire.

genetic effect:

an effect passed on to the offspring of an individual by damage to genetic material, usually by radiation or chemicals.

greenhouse effect:

the trapping in the atmosphere, primarily by CO₂, of long wavelength radiation emitted by the earth. This warms the surface of the earth and causes climate change.

greenhouse gases:

gases in the atmosphere that absorb infrared radiation from the earth: CO₂, methane, CFC's, ozone, nitrous oxides, and water.

Head:

the height of water behind a dam to the turbine below.

heat capacity:

amount of energy needed to raise the temperature of 1 cubic foot of material by 1^oF; equal to specific heat x object's density.

heat of fusion:

heat energy needed to change unit mass of object from solid to liquid at the same temperature.

heat pump:

a device that operates as a refrigerator and moves heat into the house in the winter from the outside; in the summer it cools the house, moving the heat to the outside.

HTGC (high temperature gas-cooled reactor):

a reactor that uses graphite as the moderator and gas rather than water, for heat transfer.

Hydrothermal:

the type of geothermal energy in which water heated within the earth flows to the surface as hot water or steam.

inertial confinement:

laser-induced fusion in which fuel is heated rapidly before expansion can begin.

Infiltration:

process by which cold air leaks into a house through cracks. At the same time, exfiltration is causing warm air to escape the house. Infiltration is usually measured in air changes per hour (ach).

Insolation:

incident solar radiation; measured in Btu/ft²/day or watts/m².

Insulation:

a material that slows heat loss or heat gain.

Isotopes:

nuclei that have the same atomic number but different numbers of neutrons.

Kcal:

the energy required to raise the temperature of 1 kg of water by 1^o Celsius.

kinetic energy:

energy of motion, microscopic or macroscopic.

latent heat:

heat necessary to cause a phase change in a material, e.g., going from ice to liquid, or liquid to gas, without a change in temperature.

Lawson criteria:

conditions that must be achieved in fusion for energy break-even (energy output at least as large as energy input).

Leachate:

liquid resulting from water moving through a landfill.

Leaching:

the process by which water moves through a material (e.g., garbage), picking up substances in the material.

Liquefaction:

the process of converting coal into useable liquid fuel.

LOCA (loss of coolant accident):

a nuclear accident in which a major water coolant pipe breaks, possibly leading to a core meltdown.

Magma:

hot material under the earth's crust and mantle.the federal agency responsible for the licensing and operation of nuclear reactors.

Nucleon:

general term for the proton and neutron.

off-peak period:

hours of the day when demand for electricity is low. Usually has lower prices for electricity.

Ohm's law:

the empirical relationship between the current, potential difference, and resistance in an electrical circuit: V = IR.

oil shale:

sedimentary rock containing solid organic material that can be converted to crude oil.

Overburden:

soil and rock that overlie a buried deposit of coal. In surface mining, the overburden is first removed.

passive solar heating:

using the building to collect and store incoming solar energy. Does not use fans or pumps to distribute heat through the building.

Penstock:

a large pipe that carries water to the turbine in a hydroelectric plant.

PH:

a measure of how acidic or basic a substance is. Distilled water that has a pH of 7.6 to 0 is increasingly acidic; 8 to 14 increasingly alkaline.

photoelectric effect:

the release of electrons from a metal by the absorption of light.

Photon:

a massless particle of electromagnetic energy, moving at the speed of light.

Photosynthesis:

the production of carbohydrates in a plant from water and carbon dioxide using solar radiation.

photovoltaic energy:

electricity produced from photovoltaic cells when incident sunlight is incident on the cell.

Plasma:

ionized gas, usually at a high temperature.

p-n junction:

the region of contact between p-type and n-type semiconductor materials. A depletion region exists at this junction, as well as a potential difference.

potential energy:

energy stored; a function of the object's position.

pumped storage:

a technique for storing energy by using excess electricity to pump water to a high reservoir, from which it can be used in a hydroelectric facility to generate electricity during periods of peak demand.

PURPA (Public Utilities Regulatory Policy Act):

1978 law requiring competition in the electrical generating industry.

PWR (pressurized water reactor):

a nuclear power reactor in which the cooling water is kept under a high pressure and not allowed to boil.

Quad:

an amount of energy equal to 10¹⁵ Btu.

quantized value:

a discrete value possessed by a physical quantity.

Rankine cycle:

a particular cycle in a turbine power system; the working fluid is both a liquid and vapor in the cycle.

rated speed:

the speed for which a given wind turbine is designed to produce maximum power.

Rem:

a unit for measuring absorbed doses of radiation.

Reserve:

the amount of a resource that is recoverable at current prices and with current technology.

Reversible:

a process that can have its direction changed or reversed with no affect upon the environment.

R-value:

the "resistance" of a substance to heat transfer by conduction.

shale oil:

a form of oil trapped within a rock called shale.

somatic effect:

an effect on the health of an individual receiving radiation.

specific heat:

amdi-font-size:7.5pt; font-family:Verdana'>event occurring when the temperature of a layer of air increases with height, trapping rising air pollutants.

Therm:

a measure of heat energy content; 1 therm equals 100,000 Btu. Natural gas is often measured in therms, where 100 ft³ of natural gas = 1 therm.

thermal mass:

a heat storage material, such as water or masonry, used in passive solar heating systems.

thermal neutrons:

neutrons in a reactor that have very small energies, about 1/40^th of an eV.

Thermosiphoning:

the circulation of water by natural convection.

Tokamak:

a particular type of fusion reactor using magnetic confinement, doughnut shaped.

total energy:

sum of a body's potential, kinetic, and thermal energies.

Home | Syllabus | Assignments | Schedule | Overview | Bulletin Board | Glossary | Internet Sources | Tests

absolute zero:	the lowest possible temperature, O K = -273^oC O K = -460^oF
acid deposition:	adding sulfuric or nitric acid to the environment by rain, snow, or dry sediment.
active solar heating:	heating a house by using a solar collector with pumps or fans to transfer the heat into the house.
aerosols:	solid or liquid matter in the atmosphere, usually smaller than 10 microns.Aerosols may be breathed deeply into the lungs, causing lung damage.
alcohol fuel:	fuel made by distilling grain, wood, or other plant products into alcohol.
alpha ray:	the nucleus of a helium atom consisting of two protons and two neutrons.
altitude angle:	elevation or angle of the sun above the horizon. Altitude plus azimuth angles completely determine the sun's position in the sky.
ampere:	the unit of measurement of electric current. One ampere is a flow of one coulomb of charge per second.
anaerobic digestion:	decomposition process by which bacteria convert organic material into methane in the absence of oxygen.
atomic number:	the number of protons in the nucleus. This is also equal to the number of electrons in a neutral atom.
available energy:	the maximum amount of work that can be extracted in a particular process.
avoided cost:	cost to a utility of adding new electrical capacity, expressed in cents per kwh.
azimuth angle:	angle of the sun from true south. Azimuth plus altitude angles completely determine the sun's position in the sky.
beta ray:	a positive or negative electron; a natural component of radioactivity.
binding energy:	the energy that holds a nucleus together; the difference between the sum of the masses of the individual nucleons and the actual mass of the nucleus.
Biomass:	organic material in any form: wood, crop residue, animal manure, and so forth.Biomass contains energy stored in chemical form.
Breeding:	the process whereby a fissile nucleus is produced from a nonfissile nucleus in a reactor by neutron absorption.
British Thermal Unit (Btu):	the energy required to raise the temperature of one pound of water by 1 degree Fahrenheit.
BWR:	boiling water reactor; a nuclear reactor in which the reactor water is allowed to boil to produce steam.
Carnot efficiency:	maximum efficiency for converting heat energy into work; given by (1 - T_c/T_h), with the temperatures in absolute units.
Caulking:	a soft material that can be squeezed into the cracks of a building to reduce the air flow into or out of the building.
CFC (chlorofluorocarbons):	production of both electricity and useful heat from the same fuel source.
Conduction:	the process by which heat travels through substances.
Convection:	the process by which heat is transferred by the movement of fluids.
COP (coefficient of performance):	ratio of heat transferred by a heat pump to its electricity input.
COP maximum:	the maximum value of COP allowed by the Second Law of Thermodynamics.
cross-section:	probability for a nuclear reaction to occur.
Curie:	a measure of activity; 1 Ci = 3.7 x 10¹⁰ disintegrations per second.
Darrieus rotor:	a vertical egg-beater-type wind turbine machine.
degree days (DD):	the difference between the mean daily temperature and 65^oF.Degree days are cumulative over any period of time. The heat lost from a house is proportional to degree days.
DHW:	domestic hot water.
diffuse radiation:	solar radiation received under cloudy skies; cannot be focused by mirrors or lenses.
direct radiation:	solar radiation received under clear skies. Can be focused.
doubling time:	the time required for a given quantity to double in value; approximately, DT = 70 years/% growth rate.
Demand Side Management (DSM):	utility programs used to reduce peak electrical demand and increase efficiency.
ECCS (emergency core cooling system):	a high-pressure water spray system that is used to cool the reactor core in the event of a loss of coolant accident.
Efficiency:	the ratio of the useful work output to the total energy input or energy converted.
Electrolyte:	a chemical that, when dissolved in water, will conduct an electrical current.
electrostatic precipitator:	a device for removing particulates from the combustion gases in a power plant.
EMF:	electromagnetic field, usually used in association with high voltage electrical transmission lines.
Emissivity:	measure of a material's ability to give off thermal radiation.
Enrichment:	the process in which the abundance of the fissile isotope, ²³⁵U, is increased from 0.7% to 2-3% in the uranium oxide fuel.
Entropy:	a term used in thermodynamics to measure the disorder of a system. Entropy always increases when energy is converted in an isolated system. The net entropy always increases for a system and its surroundings (environment).
Eutrophication:	enrichment of a body of water by the addition of extra nutrients, stimulating algae growth. Nitrogen and phosphorus are two common nutrients added to lakes.
eV (electron volt):	an amount of energy equal to 1.6 x 10^-19 joules.
exponential growth:	a process in which the amount of a substance has a fixed growth rate, or the change in amount of something is proportional to the amount present.
fertile material:	nuclei that do not fission but can be used to create fissionable nuclei through neutron absorption -- e.g., ²³⁸U.
first law:	conservation of energy in a thermodynamic system; the heat added + work done = the change in the total energy of a system.
fissile material:	nuclei that will undergo fission when a neutron is absorbed, e.g., ²³⁵U, ²³⁹Pu.
fission products:	process to remove SO₂ from exhaust gases in a power plant.
fluidized bed combustion:	device that produces electricity from a chemical reaction between hydrogen and oxygen.
Fusion:	the process of bringing two nuclei together to form one nucleus; energy is released through the loss of mass in the product nucleus.
gamma ray:	a high energy photon of electromagnetic energy released in some radioactive decays.
gas turbine:	a heat engine that produces electricity by using the force of hot, expanding gases to make a turbine revolve. The gases are produced by burning a fuel.
gaseous diffusion:	the enrichment of ²³⁵U by diffusion of uranium hexafluoride gas through porous barriers.
Generator:	a device that changes mechanical energy into electrical energy. It consists of a magnet and a coil of wire.
genetic effect:	an effect passed on to the offspring of an individual by damage to genetic material, usually by radiation or chemicals.
greenhouse effect:	the trapping in the atmosphere, primarily by CO₂, of long wavelength radiation emitted by the earth. This warms the surface of the earth and causes climate change.
greenhouse gases:	gases in the atmosphere that absorb infrared radiation from the earth: CO₂, methane, CFC's, ozone, nitrous oxides, and water.
Head:	the height of water behind a dam to the turbine below.
heat capacity:	amount of energy needed to raise the temperature of 1 cubic foot of material by 1^oF; equal to specific heat x object's density.
heat of fusion:	heat energy needed to change unit mass of object from solid to liquid at the same temperature.
heat pump:	a device that operates as a refrigerator and moves heat into the house in the winter from the outside; in the summer it cools the house, moving the heat to the outside.
HTGC (high temperature gas-cooled reactor):	a reactor that uses graphite as the moderator and gas rather than water, for heat transfer.
Hydrothermal:	the type of geothermal energy in which water heated within the earth flows to the surface as hot water or steam.
inertial confinement:	laser-induced fusion in which fuel is heated rapidly before expansion can begin.
Infiltration:	process by which cold air leaks into a house through cracks. At the same time, exfiltration is causing warm air to escape the house. Infiltration is usually measured in air changes per hour (ach).
Insolation:	incident solar radiation; measured in Btu/ft²/day or watts/m².
Insulation:	a material that slows heat loss or heat gain.
Isotopes:	nuclei that have the same atomic number but different numbers of neutrons.
Kcal:	the energy required to raise the temperature of 1 kg of water by 1^o Celsius.
kinetic energy:	energy of motion, microscopic or macroscopic.
latent heat:	heat necessary to cause a phase change in a material, e.g., going from ice to liquid, or liquid to gas, without a change in temperature.
Lawson criteria:	conditions that must be achieved in fusion for energy break-even (energy output at least as large as energy input).
Leachate:	liquid resulting from water moving through a landfill.
Leaching:	the process by which water moves through a material (e.g., garbage), picking up substances in the material.
Liquefaction:	the process of converting coal into useable liquid fuel.
LOCA (loss of coolant accident):	a nuclear accident in which a major water coolant pipe breaks, possibly leading to a core meltdown.
Magma:	hot material under the earth's crust and mantle.the federal agency responsible for the licensing and operation of nuclear reactors.
Nucleon:	general term for the proton and neutron.
off-peak period:	hours of the day when demand for electricity is low. Usually has lower prices for electricity.
Ohm's law:	the empirical relationship between the current, potential difference, and resistance in an electrical circuit: V = IR.
oil shale:	sedimentary rock containing solid organic material that can be converted to crude oil.
Overburden:	soil and rock that overlie a buried deposit of coal. In surface mining, the overburden is first removed.
passive solar heating:	using the building to collect and store incoming solar energy. Does not use fans or pumps to distribute heat through the building.
Penstock:	a large pipe that carries water to the turbine in a hydroelectric plant.
PH:	a measure of how acidic or basic a substance is. Distilled water that has a pH of 7.6 to 0 is increasingly acidic; 8 to 14 increasingly alkaline.
photoelectric effect:	the release of electrons from a metal by the absorption of light.
Photon:	a massless particle of electromagnetic energy, moving at the speed of light.
Photosynthesis:	the production of carbohydrates in a plant from water and carbon dioxide using solar radiation.
photovoltaic energy:	electricity produced from photovoltaic cells when incident sunlight is incident on the cell.
Plasma:	ionized gas, usually at a high temperature.
p-n junction:	the region of contact between p-type and n-type semiconductor materials. A depletion region exists at this junction, as well as a potential difference.
potential energy:	energy stored; a function of the object's position.
pumped storage:	a technique for storing energy by using excess electricity to pump water to a high reservoir, from which it can be used in a hydroelectric facility to generate electricity during periods of peak demand.
PURPA (Public Utilities Regulatory Policy Act):	1978 law requiring competition in the electrical generating industry.
PWR (pressurized water reactor):	a nuclear power reactor in which the cooling water is kept under a high pressure and not allowed to boil.
Quad:	an amount of energy equal to 10¹⁵ Btu.
quantized value:	a discrete value possessed by a physical quantity.
Rankine cycle:	a particular cycle in a turbine power system; the working fluid is both a liquid and vapor in the cycle.
rated speed:	the speed for which a given wind turbine is designed to produce maximum power.
Rem:	a unit for measuring absorbed doses of radiation.
Reserve:	the amount of a resource that is recoverable at current prices and with current technology.
Reversible:	a process that can have its direction changed or reversed with no affect upon the environment.
R-value:	the "resistance" of a substance to heat transfer by conduction.
shale oil:	a form of oil trapped within a rock called shale.
somatic effect:	an effect on the health of an individual receiving radiation.
specific heat:	amdi-font-size:7.5pt; font-family:Verdana'>event occurring when the temperature of a layer of air increases with height, trapping rising air pollutants.
Therm:	a measure of heat energy content; 1 therm equals 100,000 Btu. Natural gas is often measured in therms, where 100 ft³ of natural gas = 1 therm.
thermal mass:	a heat storage material, such as water or masonry, used in passive solar heating systems.
thermal neutrons:	neutrons in a reactor that have very small energies, about 1/40^th of an eV.
Thermosiphoning:	the circulation of water by natural convection.
Tokamak:	a particular type of fusion reactor using magnetic confinement, doughnut shaped.
total energy:	sum of a body's potential, kinetic, and thermal energies.