A device that measures gravity by observation of the period of transverse
vibration of a thin wire tensioned by the weight of a known mass; useful
for observation at sea. AGI
A seismometer that is used for measuring vibrations of structures from
other than seismic causes. AGI
vibration method of roof testing
A person's fingertips are placed against the roof, and then the roof is
struck a sharp heavy blow. Such a blow usually sets up easily felt
vibrations in an unsound roof.
The foundations of machinery installed in a building should be so designed
that the frequency of the machine is two times the natural frequency of
the combined system of machines and foundations. Hammond
An approximate grading test for coarse-grained soils. A flat paper-covered
board is inclined at a slope of 1:24. The dry and powdered sample of soil
is spread in a thin layer across the top of the board. The board is tapped
sharply and repeatedly. The soil will travel down the board, the largest
particles traveling faster and further than the smaller ones. Dependent on
the degree in which the soil spreads out, a grading can be allotted to the
soil. Nelson
a. A mechanism imparting vibration to screens, concrete consolidators, and
shaking tables.
b. A tool that vibrates at 3,000 to 10,000 cycles per minute. It can be
inserted into wet concrete or attached to formwork to compact the
concrete.
c. A device for attachment to bins or chutes to produce vibration and thus
assist in gravity flow of contained material.
A sizing screen similar to the shaking screen, but the reciprocating
movement imparted to it is of greater frequency and much smaller
amplitude--1,000 rpm and 1/4 in (6.4 mm) being typical. High-frequency
vibration is more effective than the slow movement of the shaker in
preventing blinding of holes, and the screening is more effective. It may
contain one, two, or three screen decks with water sprays for washing
products when screening. Five products ranging from plus 3/4 in (19.1 mm)
to minus 1/8 in (3.2 mm) are possible from a double-deck screen. In
general, the screen is inclined at from 12 degrees to 14 degrees for the
coarser sizes and 17 degrees to 21 degrees for the finer sizes with
counterflow operation. See also:pool washing screen; varislope screen.
Nelson
A device to concentrate and separate diamonds from gangue material. It is
based on the principle that short, sharp vibrations in rapid succession
transmitted to a greased surface cause diamonds to become imbedded in the
grease, while water washes away other materials.
The trade name for a geotechnical process that uses vibration to compact
clean sands and gravels. The vibration is combined with a water jet to
give a high degree of compaction. Hammond
An instrument for recording the ground vibrations caused by heavy quarry
blasts. The relationship between the amount of vibration, the distance
from the blast, and the weight of explosive fired may be expressed thus: A
= (KE)/D, where A = maximum amplitude in thousandths of an inch; K =
constant depending on the quarry site; E = weight of explosive in pounds;
and D = distance in feet. The constant K can be determined by firing a
specimen blast of a given size at a given distance and measuring the
amplitude of the record obtained. Amplitudes in excess of 0.04 in (1 mm)
may give rise to damage. A movement of 0.008 in (0.2 mm) can be felt, and
if used an excessive number of times may give rise to complaints of
nuisance and damage. Short-delay blasting methods with small diameter
holes reduce vibration hazards. See also:falling-pin seismometer;
seismograph. Nelson
a. One of the facets modifying normal crystal faces; they usually lie
nearly in the plane of the face they modify. CMD
b. One of the crystal faces with complex Miller indices in apparent
violation of the Bravais law requiring high densities of lattice points
parallel to prominent faces. Vicinal faces are small and diverge from
major faces by very small angles. Syn:vicinal form
See:vicinal face
Vickers' diamond hardness tester
A small impression machine, capable of testing very hard metals, finished
components, and very thin sheets. The diamond is similar to that used in
the diamond pyramid hardness test. The duration of application of the load
is controlled automatically, being always applied and removed in exactly
the same manner. This machine may also be used with a ball indenter for
the Brinell hardness test. Hammond
A test of resistance to deformation of metals or minerals in which a
pyramid-shaped diamond is forced into a polished surface of the specimen
to be tested under various static loads. The result is a function of the
average length of the diagonals of the resulting indentation.
CF:Tukon hardness test; Brinell hardness test. AGI
A development in which a groove is cut around each end of a pipe instead
of the usual threads. Two ends of pipe are then lined up and a rubber ring
is fitted around the joint. A pair of semicircular bands, forming a
sleeve, are placed around the ring and are drawn together with two bolts.
These have a ridge on both edges that fits into the groove of the pipe. As
they are tightened, the rubber ring is compressed, making a watertight
joint, while the ridges fitting in the grooves make it strong
mechanically. Victualic pipe is faster to lay because in large sizes it
does not have to be aligned perfectly and screwed in. Kentucky
A proprietary pipe joint that allows the pipes to move through several
degrees after fixing but yet to remain watertight. This joint is designed
to allow about 12 degrees of movement without causing leakage. The pipes
have specially shouldered ends that are contained by a circumferential
rubber washer held by a special circumferential-type flange. The water has
access to the inner part of the washer, on which it exerts pressure and
thereby seals the joint. Hammond; Mason
A mechanical roasting furnace similar to the Ross and Welter type.
Fay
An amorphous turquoise imitation once manufactured in Austria,
Czechoslovakia, France, and England. Having approx. the same chemical
composition, hardness, density, and fracture, it is more difficult to
detect than the various blue-stained minerals since used as turquoise
substitutes.
An open-frame N-truss without diagonal members, with rigid joints between
the top and bottom chords and the verticals. Known also as open-frame
girder. Hammond
Scot. The line of fracture of a fault or the soft earth in a fissure or on
the sides of a fault. Also spelled vise.
A magnetic iron ore. Fay