Mo3 Al; melting point, 2,150 degrees C. Although its oxidation
resistance is poor compared to other aluminides and silicides, it is good
compared to molybdenum metal. It is a refractory crucible material for
melting certain metals. Lee
Five compounds have been reported: Mo2 B , melting point, 2,120
degrees C, and sp gr, 9.3; Mo3 B2 , dissociates at 2,250
degrees C; MoB, exists in two crystalline forms: alpha MoB, melting point,
2,350 degrees C, sp gr, 8.8; and beta MoB, melting point, 2,180 degrees C,
sp gr, 8.4; Mo2 B5 , dissociates at approx. 1,600 degrees C,
sp gr, 7.5; and MoB2 , melting point, 2,100 degrees C, sp gr, 7.8,
and thermal expansion, 7.7 x 10-6 . Dodd
MoC, melting point 2,692 degrees C, sp gr, 8.5; Mo2 C , melting
point 2,687 degrees C, sp gr, 8.9. Dodd
MoSi2 ; gray; metallic; tetragonal; and melting point, 2,000
degrees C. It has good oxidation resistance at elevated temperatures;
maintains fairly good strength; and has refractory applications. Molecular
weight, 152.11; sp gr, 6.31 (at 20.5 degrees C); insoluble in acids and in
aqua regia; and soluble in hydrofluoric acid plus nitric acid.
Syn:molybdenum silicide
Most molybdenum is a byproduct of mining porphyry copper deposits.
MoO3 ; white at ordinary temperatures; yellow at elevated
temperatures; molecular weight, 143.94; orthorhombic; sp gr, 4.69 (at 21
degrees C); melting point, 795 degrees C; boiling point, 1,264 degrees C
or sublimes at 1,155 degrees C, at 1 atmophere (101 kPa); sparingly
soluble in water; very soluble in excess alkali with the formation of
molybdates; and soluble in concentrated mixtures of nitric and
hydrochloric acids and in mixtures of nitric and sulfuric acids.
CCD, 2; Handbook of Chemistry and Physics, 2
See:ferrimolybdite
See:ferrimolybdite; molybdenum trioxide.
A monoclinic mineral, PbSeO3 .
A trigonal mineral, Pb2 Mg2 Si2 O7 (OH) (sub
2) .
A method of calculating bending moments, in redundant frames and
continuous beams, using successive approximations. Hammond
The turning effect on a body about a point called a pivot or fulcrum. In
practice, the turning effect is commonly called leverage.
Syn:turning effect
Resistance by a body to angular acceleration about a specific axis of
rotation. Pryor, 3
The couple produced by the internal forces in a beam subjected to bending
under the maximum permissible stress. Hammond
Mass times velocity. Pryor, 3
Grade so situated that the kinetic energy of a train (due to its speed at
the foot of the grade) will enable the locomotive to haul the train to the
top without a reduction of speed below 10 or 12 mph (16.1 to 19.3 km/h).
Urquhart
A unique winding arrangement where two winding engines are arranged
alongside the shaft, the shaft collar forming a common foundation. The
ropes are practically vertical and there is less rope oscillation.
Sinclair, 5
A system showing, by means of lights, the position of all switchgear
underground, with a master control that would show up if a section of a
mine had been switched off at the substation, leaving switches going into
the mine in the on position. A recorder gives a complete operating picture
of a power-loading face. Nelson