Environmental Engineering Reference
In-Depth Information
Alcohol:
A general class of hydrocarbons containing a hydroxyl group (OH). There
are many types of alcohols (e.g., butanol, ethanol, methanol).
Alcohol fuels:
Alcohol can be blended with gasoline for use as transportation fuel
and can be produced from a wide variety of organic feedstock. The com-
mon alcohol fuels are methanol and ethanol. Methanol can be produced
from coal, natural gas, wood, and organic waste. Ethanol is commonly
made from agricultural plants (primarily corn) containing sugar.
Alkaline fuel cell (AFC):
A type of hydrogen/oxygen fuel cell in which the elec-
trolyte is concentrated potassium hydroxide (KOH) and the hydroxide ions
(OH) are transported from the cathode to the anode.
Alkylate:
The product of an alkylation reaction. It usually refers to the high-octane
product from alkylation units. This alkylate is used in blending high-octane
gasoline.
Alkylation:
A refining process for chemically combining isobutene with olefin
hydrocarbons (e.g., propylene, butylenes) through the control of tempera-
ture and pressure in the presence of an acid catalyst, usually sulfuric acid
or hydrofluoric acid. The product alkylate, an isoparaffin, has high octane
value and is blended with motor and aviation gasoline to improve the anti-
knock value of the fuel.
Alternating current (AC):
An electric current that reverses its direction at regularly
recurring intervals, usually 50 or 60 times per second.
Alternative fuel:
For transportation applications, alternative fuels include the fol-
lowing: methanol, denatured ethanol, and other alcohols; fuel mixtures
containing 85% or more by volume of methanol, denatured ethanol, and
other alcohols with gasoline or other fuels; natural gas; liquefied petroleum
gas (propane); hydrogen; coal-derived liquid fuels; fuels (other than alco-
hol) derived from biological materials (biofuels such as soy diesel fuel);
electricity (including electricity from solar energy); and “any other fuel the
Secretary determines, by rule, is substantially not petroleum and would yield
substantial energy security benefits and substantial environmental benefits.”
The term “alternative fuel” does not include alcohol or other blended por-
tions of primarily petroleum-based fuels used as oxygenates or extenders
(i.e., MTBE, ETBE, other ethers, and the 10% ethanol portion of gasohol).
Alternator:
A device that turns the rotation of a shaft into alternating current (AC).
Ambient:
Natural condition of the environment at any given time.
Ampere (amp):
A unit of electrical current; it can be compared to the rate of water
flowing through a pipe (liters per minute).
Ampere-hour:
Amperes times hour; used to measure energy production over time
and battery capacity.
Amphorous silicon:
An alloy of silica and hydrogen, with a disordered, noncrystal-
line internal atomic arrangement, that can be deposited in thin layers (a few
micrometers in thickness) by a number of a deposition methods to produce
thin-film photovoltaic cells on glass, metal, or plastic substrates.
Anadromous fish:
Fish that spend a large portion of their life cycle in the ocean and
return to freshwater to breed (
anadromous
is derived from the
Greek for
“up-running”).
