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NORTH AMERICA Number Members Alaska 31 Canada 302 Mexico 175 Newfoundland 3 United States Alabama 52 Arizona 131 Arkansas 9 California 723 Colorado 184 Connecticut 98 Delaware 19 District of Columbia 133 Florida 16 Georgia 6 Idaho 61 Illinois 241 Indiana 57 Iowa 7 Kansas 32 Kentucky 33

Jan 1, 1932

By J. S. Ross

Few Canadians realize the role of their domestic industrial minerals industry because it is over-shadowed in production value by a large metallic minerals industry. But since 1960, Canada has had a reasonably well balanced, mature industrial minerals industry; and although the nation's sparsely scattered population has not been able to support an industrial minerals industry in a manner comparable to the domestic and foreign support given the metal mining sector, Canada is, nevertheless, exporting large quantities of higher priced nonmetallic minerals. Production of many of the basic minerals had been firmly established long before 1960, but it was not until the late 1950's that the output of cement, salt, titanium dioxide pigment and slag, sulfur, gypsum and sodium sulfate reached relatively high levels. Shortly after 1960, the significant potash and lithium chemicals industries were established and their effect is just now being realized.

Jan 11, 1964

By S. M. Wu, R. L. Stone, T. D. Tiemann

The dissolution of silica from quartz in sodium hydroxide solutions was investigated by statistical methods. A second-order predicting equation was developed with 28 experiments expressing the dissolution of silica as a function of the variables quartz size, time, temperature and sodium hydroxide concentration. With this equation a comprehensive picture of the dissolution reaction was gained which included the effect on extraction of each variable and their interactions, fractional extractions, reaction rates and activation energies. A previous investigation of the extraction of silica from low grade siliceous iron ore by digestion in sodium hydroxide solutions presented the extraction as a function of time, temperature and sodium hydroxide concentration.' The present paper is an outgrowth of the previous work and develops by a mathematical analysis the functional relationship between the extraction of silica and time, temperature, sodium hydroxide concentration and particle size. Relatively pure quartz was used in this study in order that the basic quartz-sodium hydroxide reaction could be studied without the influence of other constituents that are commonly found in iron ores. The functional relationship between the dissolution

Jan 1, 1965

By W. R. Johnson

In the spring of 1935 the writers undertook to compare the geomagnetic and direct-current earth-resistivity methods of tracing a concealed dike along its strike. As far as they are aware no such direct test has been attempted.# The area surveyed lies along United States Highway number 15 about one and one-half miles east of Chapel Hill, North Carolina, and northeast of Bolin Creek (Fig, 1). To the south of the highway is the flood plain of Bolin Crook, and to the north is a hill that rises almost to the elevation of Chapel Hill. A diabase dike, which strikes slightly west of north, out-crops in a. gully just south of the highway. Southward it has been covered by alluvium but northward outcrops again on the southeastern slope of the hill north of the highway. South of the highway the country rock is Triassic shale and sandstone, the northern limit of which is slightly north of the road. On the Geological Map of the United States I the pre-Triassic formations are shown as lower Glenarm and assigned a pre-Cambrian age. Since the ago of the Glenarm has been called into question in Pennsylvania 2, the writers prefer not to commit themselves as to the ago of these rocks further than to say that they are definitely pre-Triassic.

Jan 1, 1937

By Samuel B. Christy

Jan 1, 1889

Jan 1, 1900

By Donald Cummings

CERTAIN dusts are dangerous when inhaled, but most hazardous of all dusts are quartz or other forms of pure crystalline silica. The inhalation of dusts containing silica in combination with other elements gives rise to changes in the lung which differ from those produced by pure silica. As a generality, silicates are less dangerous than pure crystalline silica and vary greatly among themselves in harmfulness. Repeated analyses have shown that approximately 70 per cent of the total number of particles involved in any dust-producing operation are below 1 to 2 microns in diameter. (A micron is. approximately 1/25,000 in.) Similar studies of dusts recovered from silicotic lungs post mortem have demonstrated essentially the same size frequency distribu-tion, except that the upper limit of size retained in the air sacs is approxi-mately 10 microns. Experiments carried on by Gardner and the author have further demonstrated that greater changes were produced by a fixed weight of very fine quartz particles (2 to 3 microns and smaller) than by the same weight of slightly larger particles (8 to 10 microns). Any attempt to control a dust hazard should therefore be directed toward the removal from the working atmosphere of particles less than 10 microns in size, and particularly those below 3 microns. All industrial hygienists agree on this matter, but there remains considerable dispute as to the lower limit of particle size capable of causing injury. It has been gen-erally conceded, however, that particles of harmful dusts smaller than ¼ to ½ micron are not essentially concerned in the development of pulmonary fibrosis. This opinion is partly substantiated by the existence of large numbers of these small particles in practically all atmospheres that are, not associated with any known hazard. Such particles are so small that they have very little mass, fail to settle even in quiet air, and probably are not easily retained in the lung. Until further research proves that they are involved in the dangers provoked by the inhalation of certain dusts, engineers will generally agree that it is better to dis-regard them.

Jan 1, 1935

Jan 1, 1902

Jan 1, 1892

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Jan 1, 1938

ALABAMA Alabama City.-Eddy, L. Altoona.-Cain, J. America.-Foreman, J. T. Anniston.-Foster, R. N. Ashland.-Sturdevant, J. C. Bessemer.-Ball, E. M. Calhoun, F. W. Maschmeyer, W. L. McKenzle, W. C., Jr. Birmingham.-Abbott, C. E. Aldrich, T. H. Aldrich, T. H, Jr. Ashton, J J.

Jan 1, 1923

NORTH AMERICA Number Members Alaska 32 Canada 300 Mexico 165 Newfoundland 3 United States Alabama 43 Arizona 121 Arkansas 9 California 674 Colorado 184 Connecticut 94 Delaware 19 District of Columbia 120 Florida 17 Georgia 5 Idaho 66 Illinois 211 Indiana 56 Iowa 8 Kansas 32 Kentucky 31

Jan 1, 1934

By Edward Walsh

In the early history of the production of metallic iron from the native oxides or ores, success attended the labors of the workman according to the care he devoted to his work, and according to the degree of skill he possessed in furnishing the required amounts of fuel and ores to be acted upon by the blast propelled by the bellows, trompe, or wooden tub, and delivered into the hearths of the Persian, bloomery, or Catalan forges. The same skill may also have been of avail in the use of the lower forms of the ".Stück," "Blue,"or" Wolf"

Jan 1, 1887

By R. L. Smith, J. L. Rutherford

ALTHOUGH considerable effort has been devoted toward the determination of the mechanical properties of pure metals, it is extremely difficult to compare the results of such work. This is because of differences in method and type of test, grain size, heat treatment, and purity of material. There is very little information on the properties of most of the high melting point reactive metals with purities greater than 99.9 pct. Previous evidence concerning the tensile properties of unalloyed metals show that: body-centered-cubic metals are brittle at low temperatures; face-centered-cubic metals remain ductile; some hexagonal metals remain ductile, others become brittle. It may be that traces of impurities decrease the low temperature ductility of the body-centered-cubic lattice. This would suppose that a body-centered-cubic lattice free from impurities would exhibit nearly the same ductility as a face-centered-cubic structure. The present investigation has been an evaluation of the tensile properties of zone refined iron in order to determine whether higher purity material than that previously evaluated behaves differently. Experimental Procedure In this investigation, high purity iron was zone purified using the floating zone method.' The starting stock was obtained from two sources. The first,

Jan 1, 1958

By Philip B. Bucky

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Jan 1, 1942

Jan 1, 1931

By E. C. Pechin

AT the suggestion of some members of the Institute, attention is called to the record of the working of Dunbar Furnace during the twelve months ending in January, 1874. During this period, with a product of over eleven thousand gross tons, not a single ton of

Jan 1, 1874

By G. O. Hiers

THE object of the experiments reported in this paper is to determine the eutectic composition of copper and tin and to determine the location of the part of the liquidus line immediately above the eutectic composition in copper. Three methods were used in the investigation: (1) the method of dissolving copper in a bath of molten tin at constant temperature, with the idea that when the bath was saturated with copper its copper content, by analysis, together with the temperature at which the saturation took place would locate a point on the liquidus line (2) the method of the differential cooling curves, and (3) the method of microscopic examination. This paper is principally concerned with the results of the last two methods mentioned. The results of the first method, that of dissolving copper in molten tin, did not agree with the .results of Miller,1 by the same method, nor with the results of other investigators by other methods, nor yet with the results of the cooling-¬curve experiments and microscopic examination reported here.

Jan 1, 1929

Jan 1, 1912

By R. A. Swalin, A. H. Geisler

THIS study represents an investigation of the effect of annealing temperature on the texture of drawn molybdenum, iron, and an iron alloy containing 14 pct Al. The effect of temperature on annealing textures has not been widely investigated in the past. One of the obstacles in making such a study using usual X-ray diffraction techniques results from the

Jan 1, 1957