Environmental Engineering Reference
In-Depth Information
mineral ash in the proportions of 1 part fuel to 200 parts ash, while a flow
of air passes up through the bed, causing it to act like a turbulent fluid.
Fluorescent lamp:
A glass enclosure in which light is produced when electricity
is passed through mercury vapor inside the enclosure. The electricity cre-
ates a radiation discharge that strikes a coating on the inside surface of the
enclosure, causing the coating to glow.
Note:
Traditional fluorescent lamps
are usually straight or circular white glass tubes used in fixtures specially
designed for them. A newer type of fluorescent lamp, the compact fluores-
cent lamp, takes up much less room, comes in many differently shaped con-
figurations, and is designed to be used in some fixtures originally intended
to house incandescent lamps.
Flux material:
A substance used to promote fusion, such as of materials or minerals.
Fly ash:
Particulate matter mainly from coal ash in which the particle diameter is
less than 1 × 10
4
m. This ash is removed from the flue gas using flue gas
particulate collectors such as fabric filters and electrostatic precipitators.
Flyway:
Any one of several established migration routes of birds.
Focal species:
A species that is indicative of particular conditions in a system (rang-
ing from natural to degraded) and used as a surrogate measure for other
species of particular conditions; an element of biodiversity selected as a
focus for conservation planning or action. The two principal types of targets
in conservancy planning projects are species and ecological communities.
Foliation period:
Average period when a tree is in leaf.
Forest land:
Land at least 10% stocked by forest trees of any size, including land
that formerly had such tree cover and that will be naturally or artificially
regenerated. Forest land includes transition zones, such as areas between
heavily forested and non-forested lands that are at least 10% stocked with
forest trees and forest areas adjacent to urban and built-up lands. Also
included are pinyon-juniper and chaparral areas in the West and affor-
ested areas. The minimum area for classification of forest land is 1 acre.
Roadside, streamside, and shelterbelt strips of trees much have a crown
width of at least 120 feet to qualify as forest land. Unimproved roads and
trails, streams, and clearings in forest areas are classified as forest if they
are less than 120 feet wide or an acre in size.
Fossil fuels:
A general term for combustible geologic deposits of carbon in reduced
(organic) form and of biological origin, including coal, oil, natural gas, oil
shales, and tar sands. A major concern is that they emit carbon dioxide
into the atmosphere when burned, thus significantly contributing to the
enhanced greenhouse effect.
Fractionation:
The process by which saturated hydrocarbons are removed from
natural gas and separated into distinct products, or “fractions,” such as pro-
pane, butane, and ethane.
Fracture:
Natural or induced break in rock.
Fracturing treatments:
Treatments performed by pumping fluid into the sub-
surface at pressures above the fracture pressure of the reservoir forma-
tion to create a highly conductive flow path between the reservoir and the
wellbore.
