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By M. E. Fine, A. A. Hendrickson

The critical resolved shear stress and the strain rate dependence of the .flow stress are reported for Ag base A1 single crystals up to 6 at. pct A1 over a temperature ralzge of 4.1° to 470°K. At room temperature the solid solution strengthening is attributed brinciballv to an increase in the dislocation density on alloying. At 42°K the alloys are relatively stronger because the dislocations widen on alloying and are more difficult to cut. In a previous paper, the authors reported the characteristics of strain aging in Ag base A1 alloys.' The variation of the magnitude of the strain-aging yield drops on aging time, aluminum content, and testing temperature strongly indicated that the phenomenon is due to the Suzuki mechanism. In the present paper, the critical resolved shear stress (CRSS) and the strain rate dependence of the flow stress are reported for Ag base A1 single crystals as functions of testing temperature (4.2" to 470") and A1 content (0 to 6 at. pct). Observations on the substructure and measurements of the effect of crystal growth rate are also given. The experimental re- sults appear explainable considering that aluminum additions increase the dislocation density and dislocation width. EXPERIMENTAL METHOD The methods of specimen preparation and tensile testing were described previously.' Briefly, single crystals were grown from the melt in a vacuum (1 x lom5 mm Hg), shaped into tensile samples by a combination of abrading and acid etching, annealed at 850°C in a vacuum (1 x 10" mm &Z) for several days, and furnace cooled to 200'. The testing was done on a model TM Instron using friction grips and a strain rate of about 5 x 106 per sec unless otherwise noted. The various testing temperatures were obtained by immersing the specimens in the following media: 1) 4.2': liquid helium using the apparatus of G. Byrne;' 2) 77°K: liquid nitrogen; 3) 200"K: dry ice and acetone; 4) 415' K: ethylene glycol; 5) 460' \ to 480' : molten Stanalax. In the determination of the CRSS above 296' K, a ratio method was used; the crystals were strained initially at the higher temperature, 0.1 pct shear strain, and then tested at 296' . The ratio of the flow stress between the two temperatures was then multiplied by the average CRSS at 296' K to obtain the value of the CRSS at the high temperature. (The test at 296' showed a yield point resulting from strain aging; the flow stress at 296' K was taken as the lower yield stress.) The ratio method, we believe, is more accurate than using different crystals since

Jan 1, 1962

By R. V. Ramani, Y. J. Wang, R. Mishra

Abstract-The validity of the concept of mine resistance in ventilation systems is examined. Mine resistance is the proportionality constant relating the head generated by a fan and the quantity flowing through it when the fan is connected to a mine circuit. It is the total effect of all branches in the mine ventilation circuit. Its importance lies in the fact that for new mine projections, and in the extensions of existing mines, ventilation calculations are usually based upon adjustments of the mine

Jan 11, 1978

By J. W. Hickman

INTRODUCTION MOST of the electron diffraction studies of oxide films which form on metals and alloys have been carried out by oxidizing the specimens in an auxiliary furnace, cooling down to room temperature and then inserting the sample in the camera and taking a diffraction photograph. Prior to the investigations at the Westinghouse Research Laboratories, no systematic study of the oxidation of any metal or alloy had been made over a wide temperature range with photographs taken at elevated temperatures except the investigation of iron by Jackson and Quarrell.1 In order to interpret the electron diffraction patterns of the oxides which may form on alloys, it seemed advisable to make a comprehensive study of the oxidation of the purest metals available in the bulk form. Thus far studies have been completed on iron,2 cobalt,2 nickel,2 chromium ,2 Copper2, tungsten,3 molybdenum,3 beryllium ,4 uranium,4 thorium4 titanium5 and zirconium5 while investigations are in progress on tantalum and columbium, The next step in the study is concerned with the investigation of the oxides which form on binary alloys. Some of the alloys consist of a single, phase while others contain more than one phase. The identification of the oxides on the surface of a binary alloy may be more difficult than on the metals since oxides containing both metals as well as those of each metal separately may form. Furthermore, it is possible that solid solutions of the various oxides may occur. In these cases the electron diffraction method may not be able to identify the oxidation products unequivocally, Examples of solid solutions which may present difficulties are MoO2 and W02, Fe3O4 and FeO-Cr2O3 since the diffraction patterns are so similar. Since electron diffraction can determine only the structure of the oxide, the chemical composition must be inferred from the diffraction data based upon X ray diffraction investigations of specimens of known composition. It is possible in some cases to decide whether a given solid phase reaction can occur on the surface of an alloy by a study of available thermodynamic data. Table I lists the equations for the formation of most of the oxides from the elements together with values of log10 KR for the several temperatures. [OF°R = -RT In KR 0 and-~75T = logi°KR] [?F°R] and KR are the free energy and equilibrium constant of the reaction. Calculations may be made using the values given in Table I to determine whether a given solid phase reaction is possible thermodynamically. For example, a solid phase reaction should occur between aluminum and chromium' oxide to form

Jan 1, 1948

New equipment for seabed sampling, presently at the prototype stage, operates on the principle of diamond core drilling with wire line core barrels and is designed to drill cores from the seabed at depths down to 200 m with a continuous recovery of cores from an attendant vessel. The machine operates on the seabed by remote control from a console on the vessel. Neither installation nor operation requires the use of divers. Principal Applications Principal areas of application for the drill which is dubbed Maricor include investigation drilling in the continental shelf, mapping geological conditions before large drilling platforms are installed and exploring proposed undersea tunnel routes.

Jan 11, 1973

S. LE FEVRE, Forest Glen, N. Y. (communication to the Secretary*).¬F. L. Nason thinks I could not have studied Mr. Witherbee's paper and doubts the arithmetic used, but in his discussion arrives at practically the same conclusion. He says 10 ft. thickness of ore over a square mile should give 27,878,400 tons, allowing 10 cu. ft. per ton of ore. This is correct, but if he reads carefully he will see that this depth of ore was figured as covering one-tenth of the surface, which reduces the figures to those used by Mr. Nason. I did not say, however, that there were 2,300,000,000 tons of ore in New Jersey, but that applying the same method of computation as used by Mr. Nason, to the area of the iron ore-bearing gneisses in New Jersey, we would get a total of 2,300,000,000. I did say, "In this area are located 366 magnetite mines that have been worked more or less. These lenses may easily be capable of producing (on an average) 1,000,000 tons each, and there are probably double the number listed not opened up." Thus my estimate for New Jersey, as far as any was made, would be: Probable ore 366,000,000 Possible ore in addition 732,000,000 1,098,000,000 Mr. Nason's final conclusion of his personal estimate was one-half of what he erroneously read to be the estimate given in the paper, or half of 2,300,000,000, which equals 1,150,000,000. So the two estimates seem to differ less than 5 per cent., and we have the two sister States of New York and New Jersey on an equal footing of productive possibilities in magnetic ore.

Jan 6, 1917

By J. C. Purcupile, R. L. Morris

Present methods of roof support require that first a hole must be drilled, and then a toggle belt or grouted resin bolt be set. Automating this system is very difficult. Therefore, we decided to develop a system which would insert pins into the roof in one step. We think that this type of system can be automated much easier. It would then speed up the roof bolting operation and eliminate the need for a man to work under unsupported roof, making roof bolting a much safer job. There are two ways that a pin can be inserted in a mine roof without drilling a hole. It can either be pushed in, using a very high, constant axial force; or it can be hammered in like a nail. The former method involves very high compressive stresses in the pin, and requires complicated machinery to prevent buckling. Since hammering the pin does not require high axial forces buckling is not as likely. Also, experiments have shown that there are no problems associated with getting the pin to go in straight. We chose to develop the second method. While investigating methods for hammering a pin into a mine roof, we learned that piles were being driven 10 times faster than by conventional methods with a method called "orboresonance." We decided to turn the pile driver upside down, and drive pins up into the mine roof. Sonic Pin Setting Machine The machine consists of a steel bar supported at the nodal points of its first mode of transverse vibration (Fig. 1). A mechanical oscillator, driven by a hydraulic motor, is attached to one end of the bar. This provides the forcing function for the vibrations in the bar. The hydraulic power is supplied by a portable unit. When the forcing function is near the natural frequency of the bar, large amplitudes of vibration occur and require little power input. An anvil is attached to the bar at a point of maximum deflection, providing a means for striking the pin. Since the bar is being driven near its natural frequency, it takes little energy to accelerate the bar back and forth between each hit. This means that most of the power being put into the bar is going into driving the pin. This is unlike conventional pile drivers which use most of their power to accelerate the hammer back and forth between hits. The resonant frequency of the bar we used is about 250 Hz, which is in the audible range, hence the term "sonic pin setting machine." The system benefits are: (1) elimination of the two-step drilling and pin-setting roof bolt operation, (2) increased speed, (3) more intimate contact between the formation and bolts, (4) less expensive roof bolts, (5) higher integrity, (6) potential for automatic operation. Modifications During the months from Oct. to Dec. 12, 1974, under U.S. Bureau of Mines grant No. 00144104, "Projects on Coal Extraction," six members of the senior class at Carnegie Mellon University designed and built the experimental machine. They drove three pins into the Safety Research coal mine at Bruceton, Pa., and determined that the project was worth continuing. In January 1975 we began making modifications and repairs in preparation for a more extensive program of testing at Bruceton. The major items were: 1) Design and build a collapsible pin guide to keep the pin parallel with the line of travel of the lift table. 2) Move the anvil to the center of the bar. 3) Refinish the nodal holes and install new node pins and bushings. 4) Realign the bar in its frame. 5) Install a relief valve on the lift unit to control the upward force. The upward force that we exert on the pin is relatively small, so there is no tendency for it to buckle. This means that all we need to do is hold the pin straight during its initial penetration. This allows the bushing to travel up and down in a straight line. At the beginning of penetration, the bushing

Jan 1, 1977

By B. J. Bayles, J. A. Ford, M. J. Salkind

Unidirecltonally sulidijied AL-A13Ni was found to exliibit excellent microstructural stability to 508°C. Above this temperature the transverse micvostructure coarsened in a manner analogous to "Ostwald Ripening", but the A13Ni whiskers did not spheroidize or foreshorlen. The coarsened whiskers reinforced the matrix as effectirely as the finer whiskevs and no reduction in room-temperature tensile strength mas noled after exposure for 90 hr at 96 pel 0-1 the absollite melling temperature of the eulectic. The slability was auribucted to the presence of low-index (and presurrlably lor-energy) cvystallographic interjaces between phases. The driving force for microstructural coursening was presumed to be the reduction of interfacial energy between the phases. Finer micvoslructures were found to coarsen more rapidly than those which weve imitally coarser. FIBER-reinforced metals have been shown to exhibit good short-time tensile properties at elevated temperatures.1-4 However, many elevated-temperature applications require long-time property retention which dictates the necessity for microstructural stability. Two types of instability are common to fiber composities. The first, chemical instability, is due to chemical reaction between the matrix and the relnforcing phase. Petrasek and weeton5 have shown that chemical reaction between tungsten wire and several copper alloy matrices resulted in degradation of the reinforcing phase and reduction in strength of the composite materials. Kreider and Leverant4 have noted similar behavior for boron-reinforced aluminum above 400°C. The second type of instability arises in systems in which the phases are essentially chemically stable with respect to each other and is characterized by spheroidization and/or agglomeration of the reinforcing phase. parratt6 has reported this type of degradation to occur relatively rapidly at moderate temperatures for nickel and cobalt alloys containing whiskers of silicon nitride, aluminum oxide, and silicon carbide and has identified it as "physicochemical" instability. Although both types of instability are the result of the differences in the chemical potential between the fibrous phase and the matrix, they may be differentiated by the fact that the second type, "physicochemi-call' instability, results in little or no net change in the composition or amount of each phase present. It does, however, result in a morphological change which profoundly affects the strengthening mechanism. Chemical interaction. on the other hand, results in a change in the composition and amount of one or more of the phases present, or the appearance of a new phase. In the latter case, the appearance of the mi-crostructure, that of a fibrous phase aligned in a matrix, may remain essentially unchanged, but the chemical degradation of the fiber results in markedly reduced composite strength. This investigation was initiated in an attempt to evaluate the microstructural and related mechanical property changes of a whisker-reinforced eutectic composite after elevated-temperature exposure. The composite system chosen for this study was the uni-directionally solidified A1-A13Ni eutectic which Lemkey. Hertzberg, and Ford7,8 demonstrated to behave as a whisker-reinforced composite. The microstructure of the unidirectionally solidified material consists of aligned needles of A13Ni in a matrix of aluminum. EXPERIMENTAL PROCEDURE Eutectic ingots having a nominal composition of 6.2 wt pct Ni were produced by melting 99.99+ pct A1 and 99.99 pct Ni in recrystallized alumina crucibles in an argon atmosphere. The analyses of the starting materials are listed in Table I. These master heats were cut up? melted by induction heating, and unidirectionally solidified vertically in 1/2 -in.-ID. 6-in.-long graphite crucibles, in a dynamic argon atmosphere. Therma1 gradients in the liquid were determined by measuring the temperature in the melt as a function of apparatus travel distance, as discussed by Kraft and Albright.9 The rate of solidification was assumed to be equal to the uniform rate at which the crucible assembly was withdrawn from the furnace. Ingots representative of nominal growth rates of 2, 5, and 11 cm per hr were produced and the solidification parameters are summarized in Table 11. Ingots used for met allographic analysis were pre-

Jan 1, 1968

By G. Derge, Ling Yang, John Henderson

Self-diffusion coefficients of aluminum have been measured by the capillary reservoir technique in liquids of the CaO-SiO2-Al2O3 system containirg equimolar portions of CaO and SiO2, in the temperature range 1400o to 1520oC. For the melt containing 6.0 mole pct Al2O3 the results can be expressed by the equation D = [(4.3 * 0.3) x 104] exp [(-85,000 * 17,500)/RT]cm~sec-'; for the melt containing 12.5 mole pct Al2O3, by the equation D = (5.4 i 0.2) exp [(-60,000 * 10,00O)/RT] cm2sec-: A concept of the constitution of these melts has been developed which proposes that the ratios O/(Si +Al) and Al2 O3/CaO determine the dominant species present. In recent years considerable work has been done on the system CaO-SiO2-A12O3 with a view to elucidating the structure of liquids of this system. Conductivity,' electromotive force, 3 density,4 and activity5 measurements have all contributed to an understanding of the problem, but as yet there is no entirely satisfactory theory that can account for all the observed experimental results. In principle, measurements of self-diffusion coefficients should give further information which is not obtainable in other ways. Self-diffusion coefficients for calcium, silicon,6 and oxygen7 have been measured. The present investigation extends the series of self-diffusion coefficient measurements to include aluminum and develops a concept of constitution for liquids of this system which is compatible with all the observed experimental results. EXPERIMENTAL The technique used in the measurement of the self-diffusion coefficient of aluminum was the capillary-reservoir method,8 A126 being incorporated in the melt contained in the capillary and inactive aluminum in the reservoir melt. This method was chosen because it minimizes convection currents' in the diffusion zone. It has the further advantage that the boundary conditions are such that a slight modifica- tion of Anderson and saddington's8 solution of Fick's Law yields an equation which requires measurements only of the length and the initial and final average specific activities of the solidified melt within the capillary. where t is the diffusion time, Co is the average specific activity of the melt contained in the capillary at t = O, C is the average specific activity of the melt contained in the capillary at t = t, 1is the length of the capillary, and D is the self-diffusion coefficient. The equation is of somewhat different form than those previously applied to high temperature diffusion studies because the specific activity of the melt in the reservoir was negligible both before and after diffusion. The diffusion apparatus is shown schematically in Fig. 1. It consisted of a silicon carbide resistance furnace containing the inactive melt in a graphite crucible, internal dimensions 7/8 by 4 in., enclosed in a 1 1/4- by 1 1/2- by 30-in. McDanel tube. A 3/8-in. McDanel thermocouple sheath to which graphite radiation shields and a graphite protection tube were affixed, was used to hold the capillaries. By moving this sheath through a rubber seal at the top of the McDanel tube the capillaries could be lowered into or raised out of the melt. Temperature was measured with a Pt-Pt 13 pct Rh thermocouple which was calibrated periodically against a standard couple. The furnace temperature was controlled to ± 5°C through the thermocouple immersed in the melt. Temperature variation over the depth of the melt was less than ± 3°C. The inactive melts were prepared from pure native quartz, assaying better than 99.9 pct SiO2, A.R. grade A12O3 and A.R. grade CaCO,. The same quartz and CaCO3 were used in preparing the active melts, the

Jan 1, 1962

By Paul Billingsley

WHEN I was an undergraduate at the Columbia School of Mines, the mining curriculum was subdivided into two major branches's known respectively as the Metallurgical and the Geological Options, which diverged rather widely as the course progressed. When I duly elected the Geological Option, I believed, I am sure, that this divergence would continue throughout the years. The facts have proved otherwise. The mining industry is a closely knit entity in which the search for its raw materials, called mining geology, cannot be separated from the conversion of these raw materials into marketable form, called metallurgy. The mining geologist searches for materials which the metallurgist can utilize, and only such; and whenever an advance in metallurgy opens the gates for new materials, the geologist's problem is correspondingly modified. No better instance of this relationship can be given than that seen in the Salt Lake region in recent years. Our mineral industry here is of long standing. The three principal tributary districts, Bingham, Park City and Tintic, were discovered in the 1860's and have been vigorously and intelligently developed for many decades. Their production has made the Salt Lake valley one of the world's great smelting centers. The maintenance of this industry has for years depended upon the continual development of new orebodies to take the place of those being extracted. Intensive exploration in the old districts has been supplemented by prospecting in outlying districts of lesser prominence. . Many new orebodies have been discovered, such as those of the Daly West, Silver King, and Judge mines in Park City, the Utah Apex in Bingham, and the Sioux, Colorado Chief Consolidated and Tintic Standard in Tintic. New mines in other districts have been discovered also, but without affecting the dominance of the three major districts. In all cases discoveries, to be of value, had to be of ore amenable to treatment in the available metallurgical plants. This meant that, for the most part, zincy ores, both oxide and sulfide, must remain untouched, and also that ores high in iron and ores high in silica had a fictitious value, either high or low, set by the balance of these

Jan 1, 1928

By Paul Billingsley

When I was an undergraduate at the Columbia School of Mines, the mining curriculum was subdivided into two major branches's known respectively as the Metallurgical and the Geological Options, which diverged rather widely as the course progressed. When I duly elected the Geological Option, I believed, I am sure, that this divergence would continue throughout the years. The facts have proved otherwise. The mining industry is a closely knit entity in which the search for its raw matcrials, called mining geology, cannot be separated from the conversion of these raw materials into marketable form, called metallurgy. The mining geologist searches for materials which the metallurgist can utilize, and only such; and whenever an advance in metallurgy opens the gates for new matcrials, the geologist's problem is correspondingly modified. No better instance of this relationship can be given than that seen in the Salt Lake region in recent years. Our mineral industry here is of long standing. The three principal tributary districts, Bingham, Park City and Tintic, were discovered in the 1860's and have been vigorously and intelligently developed for many decades. Their production has made the Salt Lake valley one of the world's great smelting centers. The maintenance of this industry has for years depended upon the continual development of new orebodies to take the place of those being extracted. Intensive exploration in the old districts has been supplemented by prospecting in outlying districts of lesser prominence. Many new orebodies have been discovered, such as those of the Daly West, Silver King, and Judge mines in Park City, the Utah Apex in Bingham, and the Sioux, Colorado Chief Consolidated and Tintic Standard in Tintic. New mines in other districts have been discovered also, but without affecting the dominánce of the three major districts. In all cases discoveries, to be of value, had to be of ore amenable to treatment in the available metallurgical plants. This meant that, for the most part, zincy ores, both oxide and sulfide, must remain untouched, and also that ores high in iron and ores high in silica had a fictitious value, either high or low, set by the balance of these

Jan 1, 1928

Year of Election 1944 Walter Hull Aldridge, New York, N.Y 1955 Louis S Cates, New York, N.Y 1946 William Fraser (Lord Strathalmond), London, England 1917 Herbert Hoover, New York, N Y 1955 George M Humphrey, Cleveland, 0

Jan 1, 1959

Full details of the program for the New York meeting .were given in the January Bulletin and the announcement mailed to members. The following brief synopsis is offered simply as a reminder of the principal events of this meeting which Chairman Browne says is going to be "different." Time.-Monday, Feb. 14, to Thursday, Feb. 17, 1916, inclusive. Place.-Engineering-Societies' Building, 29 West 39th St., New York. Events.-Monday, Tuesday and Wednesday (Morning and Afternoon) Technical Sessions. Tuesday, 10 a. m.: Annual Business Meeting, Luncheon served in the-Engineering Societies Building between sessions each day.

Jan 2, 1916

By Riki Kobayashi, D. L. Katz

The conditions at which methane and water form solid hydrates have been extended from 4,000 to 11,200 pounds per sq. in. The curve at high pressure had been in doubt because of Villard's report of a critical decomposition temperature. The paper explains the nature of the hydrate curve at high pressure and its dependence on fluid phase behavior. Extropolation of the methane hydrate curve indicates a pressure of 40,000 pounds per sq. in. will cause hydrates to form at a temperature of 100" F. INTRODUCTION The conditions under which natural gases form hydrates when liquid water is present have been studied by several investigators up to pressures of about 4,000 pounds per sq. in. The early work by Villard on hydrates of methane and ethylene13, ethane'', and propane14 included references to critical decomposition temperatures of the hydrates. Villard's work raised the question as to whether the pressure-temperature curve for methane-water hydrate continued above a temperature of 70.7°F. or whether this was the maximum temperature at which hydrates would form. This paper extends the experimental data on methane hydrate to 11,200 pounds per sq. in. A discussion of phase relations in the hydrate region for the hydrocarbons and of the methane-water system at high pressures is included. PREVIOUS WORK Villard suspected that methane hydrates could not be formed at temperatures above 21.5°C. (70.7°F.)la irrespective of the pressure of the liquid-vapor system. However, he was limited in his studies by his apparatus in 1888 to pressures not greater than 300 atmospheres (4,410 pounds per sq. in.) so that there has remained some doubt as to the existence of such a maximum temperature in this region. For the case of ethylene hydrates, however, Villard does specifically state the occurrence of what he terms a "critical temperature for the decomposition of the hydrates"13. Fig. lB shows a pressure-temperature projection of the three-phase locus, hydrate-ethylene rich liquid-vapor (H-L2-V) terminating at the critical locus in which L² and V assume similar properties. Throughout this paper the following phase designations will be used: H for hydrate, Ll for the water rich liquid. L2 for the

Jan 1, 1949

By Riki Kobayashi, D. L. Katz

The conditions at which methane and water form solid hydrates have been extended from 4,000 to 11,200 pounds per sq. in. The curve at high pressure had been in doubt because of Villard's report of a critical decomposition temperature. The paper explains the nature of the hydrate curve at high pressure and its dependence on fluid phase behavior. Extropolation of the methane hydrate curve indicates a pressure of 40,000 pounds per sq. in. will cause hydrates to form at a temperature of 100" F. INTRODUCTION The conditions under which natural gases form hydrates when liquid water is present have been studied by several investigators up to pressures of about 4,000 pounds per sq. in. The early work by Villard on hydrates of methane and ethylene13, ethane'', and propane14 included references to critical decomposition temperatures of the hydrates. Villard's work raised the question as to whether the pressure-temperature curve for methane-water hydrate continued above a temperature of 70.7°F. or whether this was the maximum temperature at which hydrates would form. This paper extends the experimental data on methane hydrate to 11,200 pounds per sq. in. A discussion of phase relations in the hydrate region for the hydrocarbons and of the methane-water system at high pressures is included. PREVIOUS WORK Villard suspected that methane hydrates could not be formed at temperatures above 21.5°C. (70.7°F.)la irrespective of the pressure of the liquid-vapor system. However, he was limited in his studies by his apparatus in 1888 to pressures not greater than 300 atmospheres (4,410 pounds per sq. in.) so that there has remained some doubt as to the existence of such a maximum temperature in this region. For the case of ethylene hydrates, however, Villard does specifically state the occurrence of what he terms a "critical temperature for the decomposition of the hydrates"13. Fig. lB shows a pressure-temperature projection of the three-phase locus, hydrate-ethylene rich liquid-vapor (H-L2-V) terminating at the critical locus in which L² and V assume similar properties. Throughout this paper the following phase designations will be used: H for hydrate, Ll for the water rich liquid. L2 for the

Jan 1, 1949

By Hans S. Carlsson

Like most industrial processes, nuclear power production creates wastes, which have to be handled and ultimately disposed of in a safe manner. Some of the wastes contain very long-lived radioactive substances and have to be isolated for very long periods of time before they have decayed to harmless levels. Sweden, like many other countries with similar geology, intends to use crystalline rock for isolating the high-level nuclear waste from the biosphere. The suitability of a rock mass for a repository needs to be investigated extensively. Apart from the political and practical considerations for a site selection, a detailed study has to be performed in terms of geology, hydrogeology, geophysics, geochemistry and rock mechanics. The responsibility of the site selection studies in Sweden is entrusted to the Swedish Nuclear Fuel Supply Company, Division KBS (SKBF/KBS) . The paper gives a brief presentation of the "Standard Program" for the studies that will be carried out during 1980-1990. Modifications of the program are justified on the basis of gained experience or specific circumstances for each site. The program is compiled by the Geological Survey of Sweden (SGU) in cooperation with KBS.

Jan 1, 1982

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of flay, 1913: Members. BASTIN, EDSON S., Geol U. S. Geological Survey, Washington, D. C BUCHERER, Louis, Cons. Engr Apartado 1471, Mexico City, Mexico. BURDICK, CHARLES A., Min. Engr 74 Broadway, New York, N. Y. CARR, HOMER L., Min. Engr 109 W. 88th St., New York, N. Y. CARTER, RUSSELL S., Mech. Engr. & Asst. Gent Mgr., Ingersoll-Rand Co., 11 Broadway, New York, N. Y.

Jan 6, 1913

THE iron and steel industry spent $1,170,000,000 in 1952 for improvements and expansion, with an accompanying rise of 9 million net tons in capacity to 117.5 million tons of ingots and steel for castings. More than $4,600,000,000 has been invested in the seven years following World War 11. An average of $1260 has been laid out every minute during those seven years for an increase in capacity of 25.6 million tons.

Jan 3, 1953

By J. D. Mote, A. Rosen, J. E. Dorn

The effect of strain rate and temperature on the critical resolved shear stress for (1100) [1120] prismatic slip was determined for the intermediate hexagonal phase containing about 67 at. pct Ag and 33 at. pct Al. Whereas the flow stress increased only slightly as the test temperature was first decreased below room temperature, a rapid increase inflow stress was obtained with yet greater decreases in temperature from about 240" to 4°K. The effect of both temperature and strain rate on the flow stress over the low-temperature range could be completely rationalized in terms of the Peierls mechanism when the deformation is controlled by the rate of nucleation of pairs of kinks. A few years ago Mote, Tanaka, and Dorn1 observed that the critical resolved shear stress for prismatic slip of a 67 at. pct Ag plus 33 at. pct A1 hexagonal intermediate phase by the (1100)[1120] mode decreased precipitously as the test temperature was increased from 4" to about 160°K. Their results for both basal and prismatic slip are given in Fig. 1. It is obvious that only the flow stress for prismatic slip is strongly temperature-dependent, whereas the flow stress for basal slip is independent of temperature. If the temperature dependence of the flow stress were primarily due to interstitial impurities, it might be expected that they would influence the flow stress for basal slip as well. Since the activation volume at 115°K for prismatic slip was determined to be about 15b3, where b is the Burgers' vector, this thermally activated deformation process was tentatively ascribed as being due to the Peierls mechanism. But the various analyses of the Peierls mechanism then available as formulated by Seeger2 and also by Lothe and Hirth3 did not agree well with the experimental data. Since that time a more realistic theory for the operation of the Peierls mechanism under conditions where the strain rate is determined by the rate of nucleation of pairs of kinks has been presented by Dorn and Rajnak.4 The present investigation was, therefore, undertaken in order to provide the essential data for a careful check on the agreement between this theory and the low-temperature deformation by prismatid slip of the above-mentioned Ag2A1 intermediate phase. EXPERIMENTAL TECHNIQUE Single-crystal specimens so oriented that the [1120] direction and the normal to the (1100) plane were at 45 * 2 deg to the tensile axis were grown from the congruent melting composition of about Ag2Al for the intermediate hexagonal phase by the

Jan 1, 1964

By Kenneth L. Clifford, Thomas G. White

Many changes have occurred in lead-zinc milling in the U.S. since the 1970 Lead and Zinc Symposium. New mills have been built, novel flowsheets devised, and the use of process control techniques is increasing. The Missouri concentrators produced in 1976 more lead and zinc concentrate than those in any other state. The Tennessee mills produced nearly as much zinc concentrate in 1976 as Missouri and with some very highly developed flowsheets. Progress in the Western U.S. is centered around new operations in Colorado and Utah. New mills in New York and Missouri incorporate many of the newer control concepts. Most of the older concentrators have undergone flowsheet changes to accomodate different ore types or because of the availability of new and better equipment.

Jan 1, 1977

By J. O. CHESLEY

CURRENT widespread applications of aluminum in such industries as transportation, mining, and construction would have amazed the early proponents of its use, including Napoleon III, French Emperor Batik ill the middle nineteenth century, when aluminum was a precious metal, Napoleon had visions of making his army light and mobile through the use of aluminum for gun carriages, helmets, canteens, sabers, and similar articles. Whereas the emperor failed in his objectives, the modern Napoleons of industry have .been successful, and today aluminum finds its greatest applications wherever there is mass ill motion. Its lightness has made possible such modern marvels as the Union Pacific streamline trains, the Boeing and Douglas giant airships, and up-to-date mining equipment such as the new Calumet and Hecla mine skips.

Jan 1, 1938