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Jan 1, 1914

Jan 1, 1881

Jan 1, 1961

Jan 1, 1934

Jan 1, 1931

By A. M. Lovelace

Introduction One area of engineering utilization of materials in which the requirements are especially rigorous and demanding is that of aerospace systems, including aircraft, helicopters, missiles, and space satellites. Materials used in these systems must reliably perform many critical functions in a broad range of adverse environments. Some of the most critical functions are performed by polymeric nonmetallic materials such as elastomers (rubber), coatings, fibrous materials, and reinforced plastics. These types of polymeric materials have some common characteristics that make them attractive to aerospace system designers: light weight, corrosion resistance, and relative ease and low cost of processing and fabrication. Each type also has its own special characteristics that enable it to perform certain required functions better than other competing materials can (Table 1). The desirable properties of polymeric materials, which in some applications make them the only practical candidates, are partly offset by their principal limitation, which is degradation by exposure to high temperature. [ ]

Jan 1, 1971

Jan 1, 1889

Jan 1, 1938

Jan 1, 1951

Jan 1, 1942

By R. S. Dean

PROCESSES for the direct production of iron and steel from ores are hardy perennials, and new processes and revivals of old ones are continually being brought to the attention of the investing public if not to the attention of metallurgists. Direct production of iron and steel is so simple that it offers a fertile field for the promoter. Unfortunately in this way direct processes have acquired a bad name, not always deserved, with conservative capitalists and metallurgists. Direct processes cannot, except in special instances, be looked upon as a substitute for any single operation in present iron and steel practice but must be considered, as one link in an entirely new chain of metallurgical process from ore to finished steel. Thus it is, in my opinion, inadvisable to consider the use of sponge-iron processes as a means of treating ore of ordinary blast-furnace grade to produce open-hearth feed. In time I think it will be found equally inadvisable to smelt iron-ore concentrates in the blast furnace.

Jan 1, 1935

Jan 1, 1949

Jan 1, 1910

Jan 1, 1936

Jan 1, 1894

By GILBERT C. DAVIS

ANY thought of Morenci naturally includes its sister town of Clifton, its gateway to the outside world. Clifton, the country seat of Greenlee County, is the terminus of a branch line of the Southern Pacific railroad from Lordsburg, N.M. Carload freight incident to the Morenci operation moves from Clifton over Phelps Dodge?s standard-gauge industrial railroad. Private freight must be hauled by truck. These two communities fell far short of supplying adequate housing for the personnel concerned with the new operations so a new townsite, Stargo, was developed adjacent to Morenci. Here 234 housing units with garages have been built and twenty similar units have been erected near the reduction works.

Jan 1, 1942

By Howard A. Meyerhoff

AS a source of mineral wealth, the larger islands of the West Indies have never had an enviable reputation. The Spaniards took possession of them in the sixteenth century hopeful that they would yield gold; but it was not long before they knew the rather rigid limitations of Antillean gold production and were seeking-and finding ---richer deposits of the precious metals in Mexico and on the west coast of South America. Although a great deal of wealth changed hands in the West Indian islands in subsequent years, the fact may be laid to the abundance of pirates and privateers and not to the richness of local ore bodies.

Jan 1, 1941

By AIME AIME

THE STANDARD herewith submitted is the result of several years of research and consideration by the A.I.M.E. Technical Committee on Milling Methods. In the early work of this committee it was found necessary to undertake the development of a standard laboratory method for screen testing of ores. During the research stages the desirability of having this standard, when completed, approved as American Standard was brought out. In accordance with this idea, its initiation as a project of the American Standards Association (then the American Engineering Standards Committee) was approved by the latter body and the A.I.M.E. designated as sponsor. In 1929, the A.S.A., on recommendations of its advisory committee, the Mining Standardization Correlating Committee), authorized the A.I.M.E. to be sole sponsor for this project. The personnel of the Institute's Committee on Milling Methods was then increased to make it thoroughly representative of all diversified interests in the mining field. Two years ago the standard was circulated and has been given wide distribution. Early in 1932 the committee voted unanimously, with 38 affirmative votes, that the standard be recommended to the Board of Directors of the Institute for submission to the American Standards Association for approval as American Recommended Practice. This was accordingly done, at the Feb. 1.6, 1932, meeting of the directors, and the American Standards Association approved the standard on July 6; 1.932, designating it as ASA M5-1932.

Jan 1, 1932

By Yves Dardel

INTRODUCTION SINCE the first determination of Dumas1 in 1880, many authors have tried to measure the solubility of hydrogen in solid aluminum, or at least the amount of dissolved gas in it. However, the interpretation of the results which have been obtained is still difficult. Sieverts,2 then Baukloh and Oesterlen,3 during their gassing experiments could not determine any solubility of hydrogen in solid aluminum. On the other hand, Portevin, Chaudron and Moreau,4 leaving the determination of the hydrogen solubility beyond the scope of their experiments, measured only the amount of gas that they could extract by high voltage positive ion bombardment and found up to 151 cm3 of gas per 100 g of metal. Winterhager,5 by repeated vacuum extraction during severe cold rolling, extracted up to 161 cm3 per 100 g. In both series of experiments, the extracted gas contained chiefly hydrogen with a small amount of nitrogen, carbon monoxide, carbon dioxide and methan. Later, Schmidt and von Schweinitz6 as well as Chaudron and Moreau7 showed the importance of the adsorbed layer of hydrogen, the extracted quantities being proportional to the surface and not to the weight of the sample, when its cleaning was not perfect. In earlier experiments, Steinhauser8 extracted from more massive samples nothing but a little amount (< 0. 5 cm3 per 100 g) of hydrogen, carbon monoxide and methane. Thus, according to these experiments the quantity of dissolved gas is probably very small and the effect of the surface could falsify the results of the extraction. However, owing to the care taken by Chaudron and his coworkers, it was clear that all the hydrogen extracted could not come from the superficial layer, or that the links which bound hydrogen to the surface were so strong that the usual method of cleaning could not destroy them. After the main parts of the experiments reported here had already been carried out, Eborall and Ransley9 published the results which they obtained with an analysor having an accuracy of 0.03 cm3 per 100 g, while that of the usual apparatus was only about 0.2 cm3 per 100 g. During all their experiments the adsorbed layer would have been a difficulty, for the value of the adsorbed hydrogen was approximately equal to that of the dissolved amount. [ ] Since always keeping the same adsorbed layer is very difficult, an error in the correction for the adsorption can be made when using the apparatus of Eborall and Ransley, as well as the earlier apparatus,

Jan 1, 1948