An instrument for making physical observations upon standing waves. It may
be used, e.g., to measure velocity, wavelength, absorption, or impedance.
Hunt
A continuous record made in a borehole showing the velocity of sound waves
over short distances in adjacent rock; velocity is related to porosity and
nature of the liquid occupying pores. AGI
A unidirectional steady-state pressure exerted upon a surface exposed to
an acoustic wave. Such a steady pressure is usually quite small in
magnitude and is really observable only in the presence of very intense
sound waves. Hunt
An instrument for measuring acoustic-radiation pressure by determining the
unidirectional steady-state force resulting from reflection or absorption
of a sound wave at its boundaries. Hunt
Product of longitudinal wave velocity and density, being the property that
controls the reflective power at a boundary plane. Schieferdecker
The study of sound, including its production, transmission, reception, and
utilization, esp. in fluid media such as air or water. With reference to
Earth sciences, it is esp. relevant to oceanography. The term is sometimes
used to include compressional waves in solids; e.g., seismic waves.
AGI
The irregular reflection, refraction, or diffraction of sound waves in
many directions. Hy
The indirect evaluation of water depth, using the principle of measuring
the length of time necessary for a sound wave to travel to the bottom,
reflect, and travel back to the water surface. Hunt
An instrument for measuring strains; e.g., in concrete linings to shafts
or roadways. It contains a length of fine wire under tension, the tension
being varied by the strain to which the gage is subjected. The measurement
made is that of the frequency of vibration of the wire when it is plucked
by means of an electromagnetic impulse, and this measurement can be made
with great accuracy. The gage is highly stable, and readings can be made
over a period of years without any fear of zero drift.
See also:electrical resistance strain gage; mechanical extensometer.
Nelson
An instrument designed to provide a continuous vertical profile of ocean
currents at a specific location. Hunt
a. The waves that contain sound energy and by the motion of which sound
energy is transmitted in air, in water, or in the ground. The wave may be
described in terms of change of pressure, of particle displacement, or of
density. AGI
b. Used increasingly to study the physical properties of rocks and
composition of gases. Investigations may be made both in situ and in the
laboratory. Nelson
Defined by the U.S. Department of the Interior as "lands in Federal
ownership which were obtained by the Government through purchase,
condemnation, or gift, or by exchange for such purchased, condemned, or
donated lands, or for timber on such lands. They are one category of
public lands." Public land laws are generally inapplicable to acquired
lands. SME, 1
a. A measure of surficial area, usually of land. The statute acre of the
United States and England contains 43,560 ft2 (4,840 yd2;
4,047 m2 ; or 160 square rods). The so-called Scotch acre
contains about 6,150 yd2 (5,142 m2 ), and the Irish acre
7,840 yd2 (6,555 m2 ). There are various special or
local acres in England (as in Cheshire or among the hop growers), varying
from 440 yd2 (368 m2 ) to more than 10,000 yd2
(8,361 m2 ). Standard, 2
b. Can. In Quebec, a linear measure that equals the square root of 43,560,
or approx. 208.7 ft (63.6 m). Fay
c. For the calculation of coal reserves, a convenient rule is to allow
1,200 st/ft (coal thickness) per acre (8,821 t/m/ha). For known and
dependable areas, 1,500 st/ft per acre (11,027 t/m/ha) may be used.
Nelson
Royalty or rent paid by the lessee for working and disposing of minerals
at the rate of so much per acre.
The quantity of water that would cover 1 acre, 1 ft deep (1 ha, 13.6 cm
deep). One acre-foot contains 43,560 ft3 (1,233 m3 ).
The volume of water, soil, or other material that will cover 1 acre, 1 in
deep (1 ha, 1.1 cm deep). AGI
The average quantity of oil, gas, or water recovered from 1 acre (0.4 ha)
of a reservoir. AGI
See:acetamide
A chemical element with atomic number greater than 88; all are
radioactive. Syn:actinide element
a. One of the group of chemical elements of increasing atomic number,
starting with actinium (atomic number 89) and extending through atomic
number 103. These elements occupy one single place in the extended
periodic table, in the same group into which the rare-earth elements
(lanthanides) are classified. See also:actinide
b. One of the radioactive elements, atomic numbers 89 to 103.
Hurlbut
A monoclinic mineral, 2[Ca2 (Mg,Fe)5 Si8 O22
(OH)2 ] in the hornblende series Mg/(Mg+Fe2+ ) = 0.5 to
0.89 of the amphibole group; forms a series with tremolite; green, bladed,
acicular, fibrous (byssolite asbestos), or massive (nephrite jade);
prismatic cleavage; in low-grade metamorphic rocks. Syn:actinote;
strahlite. CF:tremolite