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By L. R. Velho, N. A. D. Parlee, J. Gani

THE unsteady-state type of gas-liquid metal diffusion cell1 has found considerable application.2"4 Cells of this general design can function as steady-state cells if allowed to operate long enough to reach steady state. This report tells of some success in the adaption of this type of cell for steady-state work, using the 0-Ag system in which the mass transfer of the gas "species" is basically controlled by diffusion in the liquid. The gas, e.g-., O2, is maintained in the cell tube'-3 at 1 atm pressure, Fig. 1, by buret and sensitive oil manometer. The gas, after diffusing through the stagnant metal, escapes at the annular metal surface around the tube at a lower constant partial pressure, in this case that of O2 in slowly flowing air, 1 atm.

Jan 1, 1970

By K. H. G. Ashbee, J. W. Heavens

One consequence of the distribution in orientation of Bragg diffracting planes in an elastically bent foil is that simultaneous diffraction occurs from ±g pairs, where g is the reciprocal lattice vector to a diffracting plane. If such Bragg contour pairs are indexed, then the variation in orientation with respect to the incident electron beam is known. This note describes a construction by means of which Bragg contour pairs may be indexed by inspection. Referring to Fig. 1, the Ewald sphere radius is l/h, where is the wavelength of the electron beam, and the half spacing of first-order reciprocal lattice planes is l/d, where d is the corresponding spacing in direct space. The angle subtended by the zero and first-order planes at the center of the Ewald sphere is a = sin-' Thus, to represent a pair of first-order Bragg contours on a stereographic projection, measure ±a from, and along the normal to, the zero-order plane. The traces of the required Bragg contours pass through these points and parallel to the zero-order trace. In practice, it is desirable to enlarge a stereographic projection of the zero-order planes before making the construction. As an example, a stereographic projection of first-order Bragg contours up to line 27 for an fcc crystal is given in Fig. 2; if required, higher-order contours can easily be added. Fig. 2 is, of course, a map of first-order Brillouin zone boundaries. One use of this construction is the measurement of large elastic fields in electron microscope specimens. Fig. 3(a) shows a pattern of Bragg contour pairs due to lattice distortions near a large precipitate. This particular example is of a T-phase precipitate in Hidu-minium 54 (A1 + 6 wt pct Cu, 0.5 wt pct Mn). Foil buckling is produced by annealing during observation and may be evidence for evaporation from the precipitate.' Comparing Figs. 2 and 3(0), it is evident that the axis of high symmetry in Fig. 3(a) is [lll]. The strain in a bent foil is approxinlately t/2r, where / is the foil thickness and ? the radius to which the foil is bent. From the projections of grain boundaries and of helical dislocations, it was estimated that ( - 3000A, and values for ? were obtained from the

Jan 1, 1968

By A. A. Berk

LAGGING technology and the slow spread of information have been the chief obstacles to widespread participation in minimizing the industrial pollution load. These obstacles can be conquered by fact finding and applied research. There are three aspects to the problem of water-borne mineral waste: to minimize the amount being thrown away, to select a predisposal treatment, and to use the products or dispose of them. It is often possible to minimize the waste by making very minor changes in the process that produces it. For example, a manufacturer of automobile bumpers greatly reduced the dragout 'from a plating bath by modifying the design and position of two boltholes.' A plater of automobile hubcaps installed a drainage bar and decreased the loss of chrome-plating solution to the rinse water by about 80 pct.' The mill at a western mine found it possible to discard 60 to 70 pct of an ore with minimum treatment," so that the processing effort could be concentrated on a high-graded slime, with significant reduction in costs and improvement in recovery. The possibilities for waste reduction through process changes are limited only by the imagination. A recent patent points out the advantages of using No. 1 fuel oil instead of water in wet-process cement making;& the fuel oil presumably has better properties than water for this purpose and is said to be almost com'pletely recovered or utilized, so that there is no waterborne waste. Recycling to reduce wastes and improve process economy is very well illustrated in vanadium and uranium recoveries from relatively low grade ore. Ores containing 6 pct calcium carbonate were found to give poor vanadium recovery by the salt-roasting process because the vanadium was converted to water-insoluble calcium vanadate. Following the salt-roasting process, sulfuric acid was used to leach the uranium. Enough calcium sulfate was formed

Jan 1, 1958

By AIME AIME

BECAUSE of its unequalled skill, your country in- creased its production until, in 1913, it produced 40 per cent. of the world's consumption of coal, iron ore, and cast iron; 45 per cent. of the steel; and 60 per cent. of the copper. Your industrial effort, in a general manner and your mining effort in particular, has been tremendous. In the general economy of the world, you occupy an incomparable position of power and action. All your curves of production, mineralogical, metallurgical, financial, commercial, have taken terrific trigonometrical tangents and you will easily under- stand the sorry position of your competitors. I must, therefore, pay a tribute of homage arid admiration to you all who, each in his sphere, have been the artisans of such prosperity and my earnest wish is that you continue in this way.

Jan 1, 1920

By AIME AIME

BERYLLIUM is one of the most interesting of the minor metals and distinctly a modern development, for until the last two decades it had practically no commercial importance whatever. Then it was discovered that when small quantities of it were alloyed with copper, a copper alloy of unusual and valuable qualities resulted. This is by far its major use-in the manufacture of strong, heat-treated copper-base alloys in which the beryllium content varies from about 0.3 to 2.5 per cent. Its second most important use, though much smaller, is in the form of oxide or other nonmetallic products in the fluorescent lamp, X-ray, cathode ray, and television industries. Certain beryllium salts have the quality, in common with several other materials, of transforming short-wave radiation and cathode rays to visible radiation. Such materials are commonly known as phosphors, and the beryllium salts are the most important phosphors now in use. The third largest use for beryllium is for ceramics, including refractories. Beryllium is also used in small quantities in the form of the metal itself.

Jan 1, 1943

By A. L. Moore

KAISER Bauxite Co., a subsidiary of Kaiser Aluminum & Chemical Corp., has been mining and shipping Jamaican bauxite for over a year. On Feb. 10, 1953 the first boat load of bauxite left Port Kaiser, Jamaica, for the company's alumina plant at Baton Rouge, La. To provide its own source of the aluminum ore, a Kaiser Aluminum & Chemical Corp. exploration party started initial reconnaissance in 1947. This work, and subsequent exploration, led to the acquisition of reserves sufficient to warrant a full-scale mining operation for several decades.

Jan 3, 1954

By M. G. Benz

The superconducting performmce of diffusion-processed Nb3Sn is influenced by its micro structure. High isotropic transverse current density may be achieved in this material by a process which forms a precipitate of ZrO, within the Nb3Sn. FOR an ideal type-I1 superconductor, little or no transport current can be carried in the mixed state; i.e., little or no transport current can be carried above the lower critical field H,,, where the field penetrates abruptly in the form of current vortices or fluxoids, even though full transition to the normal state does not occur until the upper critical field H,,.' Fortunately, nonideal type-I1 superconductors can be readily obtained and these carry large transport currents up to the upper critical field H. Both theoretical and experimental investigations have attributed this current-carrying capability for nonideal type-I1 superconductors to pinning of the fluxoid lattice by heterogeneities in the microstructure of the superconducting material. These heterogeneities may take the form of dislocations or dislocation clusters,2"5 grain boundaries: structural imperfections introduced by phase transformations; radiation damage,8"10 or precipitates.11"15 Nb3Sn formed by diffusion processing is a type-I1 superconductor. Heterogeneities are needed for high superconducting critical currents above H,,. This paper will cover: a) what the microstructure of diffusion-processed NbSn looks like; b) what changes in the microstructure take place when the system is doped with precipitates, and c) how these changes in microstructure influence the superconducting critical currents. EXPERIMENTAL Preparation of Samples. Diffusion processing was used to form the Nb3Sn. The procedure used was as follows: a) coat the surface of a niobium tape with tin; b) heat-treat this tape at a temperature above 930°C to form a layer of Nb3Sn at the Sn-Nb interface. Such a layer of NbsSn is shown in Fig. 1 The thickness of the NbsSn layer formed was controlled by the time and temperature of the heat treatment. The same general procedure was used for preparation of both undoped samples and samples doped with a precipitate. An additional step was included in the preparation of the doped samples which consisted of internal oxidation of zirconium to form ZrOn. The details of the doping process will be reported in a later paper. Sample Testing. The Nb3Sn tape samples were soldered to a copper or brass shunt. Current and voltage leads were then attached to the sample in the usual four-probe resistance measurement configuration. The sample was cooled to 42°K. In some cases it was cooled in the presence of a high magnetic field and in other cases with the field turned off. The results were the same for both cases. The samples were oriented in a configuration with field transverse to current but could be rotated such that the angle between the field vector and the wide side of the tape sample could be changed. Measurements up to 100 kG were done in a superconducting solenoid and measurements above 100 kG in a water-cooled copper magnet at the MIT National Magnet Laboratory. Once the test field was reached, the current in the sample was increased until voltage was detected across the sample. The critical current was taken as the current at which voltage was first detected in excess of background noise. In most cases this was 1 to 2 x 10~6 v for a— in.-wide sample carrying several hundred amperes with a in. separation between voltage leads and with a 10 "-ohm shunt resistance. RESULTS AND DISCUSSION Microstructure. Examination of the microstructure of the undoped Nb3Sn shows rather large-diameter (1 to 2 columnar grains growing outward from the niobium surface toward the tin surface. As the layer is made thicker by longer diffusion times, these grains grow longer. Few new grains are started. Transmission electron microscopy shows little or no second-phase material within the bulk of the Nb3Sn layer. The microstructure of a diffusion-processed NbsSn layer changes quite drastically when the system is doped so as to form a precipitate within the NbsSn layer. Instead of large-diameter columnar grains of NbaSn forming, smaller-diameter (0.5 to 1 ) equiaxed grains of Nb3Sn decorated with the precipitate form. Fig. 2 shows a transmission electron micrograph of a Nb3Sn layer doped with zirconium oxide. This layer has been etched so that one may look between the grains

Jan 1, 1969

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890 JOHN BIRKINBINE 1891-1892 H M HOWE 1893 JOHN FRITZ 1894 J D WEEKS 1895 E G SPILSBURY 1896 THOMAS M. DROWN 1897 CHARLES KIRCHHOFF 1898

Jan 1, 1938

The regular activities of the Institute are financed mainly by income derived from members' dues, from advertising in MINING ENGINEERING, JOURNAL OF METALS, and JOURNAL OF PETROLEUM TECHNOLOGY, and from the sale of publications to the public In addition, collateral activities and special projects are financed each year by means of income - from endowed funds controlled and administered by the Institute. An active effort is being made to increase the endowment funds of the Institute through a standing committee, of which Wilfred Sykes is Chairman, and of which the other members are N G

Jan 1, 1952

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890 JOHN BIRKINBINE 1891-1892 H M HOWE 1893 JOHN FRITZ 1894 J D WEEKS 1895 E G SPILSBURY 1896 THOMAS M. DROWN 1897 CHARLES KIRCHHOFF 1898 JAMES DOUGLAS 1899-1900

Jan 1, 1952

By William E. Ford, Edward Salisbury Dana

The Nitrates being largely soluble in water play but an unimportant r81e i~ Mineralogy. SODA NITER. Rhombohedral. Axis c = 0.8276; rr" 1071 A 7101 = 73' 30'. Homeo- morphous with calcite. Usually massive form, as an incrustation or in beds. Cleavage: r (1011) perfect. Fracture conchoidal, seldom observable. Rather sectile. H. = 1.5-2. G. = 2'262.29. Luster vitreous. Color white; also reddish brown, gray and lemon-yellow. Transparent. Taste cooling. Optically -. w = 1'5874, e = 1'3361. Camp. - Sodium nitrate, NaN03 = Nitrogen pentoxide 63'5, soda 36'5 = 100.

Jan 1, 1922

IRON AND STEEL DIVISION Established as a Division February 22, 1928 K C. McCutcheon, Chairman T. L. Joseph, Past Chairman J B Austin, Vice-Chairman E K Miller, Vice-Chairman T. J. McLoughlm, Vice-Chairman Ernest Kirkendall, Secretary-Treasurer CO M M I T T E E S EXECUTIVE J. A. Bowers '54 J. S. Marsh '55 R. W. Campbell '54 D. L. McBride '53 Walter Carroll '55 G. B. McMeans '53 K. L Fetters '53 F. L. Toy '54 H. M. Griffith '55

Jan 1, 1952

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890 JOHN BIRKINBINE 1891-1892 H M HOWE 1893 JOHN FRITZ 1894 J D WEEKS 1895 E G SPILSBURY 1896 THOMAS M. DROWN 1897 CHARLES KIRCHHOFF 1898 JAMES DOUGLAS 1899-1900

Jan 1, 1952

HENRY G. MARTIN,* Chicago Heights, 111. (written discussion?).-. The object in taking three or more ladle tests is to secure a sample that will show the average composition of the heat, not primarily to investigate the lack of uniformity existing; however, the assumption that the samples are not of uniform composition -remains. In other words, we have three samples of steel of different composition, the par-ticles of which are not subject to extreme comminution so as to mix inti-mately, and yield an average homogeneous sample, if placed in one

Jan 11, 1919

[Arizona BRENT N. RICHARD, Chairman ROBERT W. HUGHES, Vice-Chairman ROBERT E. S. HEINEMAN, Secretary-Treasurer Arizona Bureau of Mines, University of Arizona, Tucson, Ariz. THOMAS G. CHAPMAN A. MENDELSOHN WILLIAM KOERNER A. C. REIFSNIDRR C. R_ . KUZELL WILLIAM M. SABEN ERNEST WITTENAU Black Hills NATHANIEL HERZ, Chairman C. E. DAWSON, First Vice-Chairman BANCROFT GORE, Second Vice-Chairman C. E. SCHMIDT, Secretary-Treasurer Homestake Mining Co., Lead, S. D. R. S. BLITZ NATHANIEL HERZ C. E. DAWSON A. I. JOHNSON L. B. EAMES F. C. LINCOLN BANCROFT GORE C. E. SCHMIDT]

Jan 1, 1940

I-Mine Ventilation A C. CALLEN, Chairman E A. HOLBROOK, Vice-chairman H I. SMITH, Secretary CLARENCE E. ABBOTT ALFRED W. HESSE FRANK H. PROBERT GRAHAM BRIGHT G R. JACKSON GEORGE S RICE THOMAS H. CLAGTETT JAMES F. MCCARTHY E. J RISTEDT OSCAR A GLAESER W. B. PLANK GERALD F. SBERMAN, Coal Mining M D COOPER, Chairman HOWARD N EAVENSON JOHN A GARCIA THOMAS D THOMAS CHARLES ENZIAN JAMES W PAUL C M YOUNG JOHN J. RUTLEDGE Physiological Studies R R. SAYERS, Chairman C. L. BERRIEN W. D. BRENNAN A. J. LANZA

Jan 1, 1923

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890 JOHN BIRKINBINE 1891-1892 H M HOWE 1893 JOHN FRITZ 1894 J D WEEKS 1895 E G SPILSBURY 1896 THOMAS M. DROWN 1897 CHARLES KIRCHHOFF 1898

Jan 1, 1937

George Otis Smith, Washington, D. C. (communication to the Secretary) : The somewhat exceptional features discussed by Dr. Jenncy in his paper on " The Mineral Crest" mere recognized and described by Mr. Tower in our report on the Tintic district. The general absence of surface-outcrops of important ore-bodies, and their occurrence, when present, at relatively low points, are noticeable characteristics of this district, and the statements made by Dr. Jenncy agree in general with our observations. The approximately horizontal upper limit of the Silver Gem ore-body in the Bullion-Beck mine is figured in this report, and mention made also of the horizontal pipes of ore found in several mines." In only one case," however, was any hypothesis

Jan 1, 1903

By J. V. W. REYNDERS

FIRST of all let me express my affectionate gratitude for the cordiality and good will of your reception. On the part of the men I venture to interpret the character of your greeting, not only as a recognition of the position to which you have been good enough to elect me, but also as an expression of your friendly attitude. However, I cannot pass over the tribute of the ladies so casually: Nor does it seem possible to do justice to my sentiments in addressing them collectively. I would feel more equal to the task if I could have the opportunity to talk to them singly, in doing which I know I may count upon their good sportsmanship not to compare notes. There has been some discussion between Mr. Kelly and myself as to our respective duties on this occasion: The precedents are not clear as to whether the retiring or the incoming president is expected to speak at length. Mr. Kelly's argument was that as the incoming president confines himself to promises for the future his field is a broad one and his opportunities for extending his remarks correspondingly unlimited.

Jan 1, 1925

By Zay Jeffries

A. G. WORTHING, Nela Park, Cleveland, Ohio (communication to the Secretary*).-The paper by Mr. Jeffries is very interesting. He is to be commended for his pioneer work in the study of equilibrium systems at the very high temperatures which one obtains with tungsten and molybdenum. There is one statement, however, to which I must take exception. On page 1227, a statement is made which would seem to indicate that the Nela Research Laboratory joined Dr. Langmuir in the recommendation of 3,300°C. as the most probable melting point of tungsten. This is not the case. In. the paper referred to by Mr. Jeffries, I have given 3,630°K. or 3,357°C. as the melting-point temperature for tungsten. Confirming observations by other workers in our laboratory justify the belief that this latter value is correct to within a small part of the discrepancy between the two values quoted.

Jan 12, 1916