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By R. L. Andelin, J. D. Knight, M. Kahn

Self-diffusion in single-crystal tungsten and diffusion of rhenium tracer in single-crystal tungsten have been measured over the temperature range 2660° to 3230°C by direct sectioning and radio-chemical analysis of W185 and Re183 and Re184 tracers. The initial radioactive layer was produced on the diffusion specimens by bombardment with 9.0-mev deuterons. Diffusion heating of the samples in high vacuum was accomplished by induction heating. Temperatures were measured by optical pyrometry, and the system was calibrated ALTHOUGH a considerable body of experimental information has been accumulated on self-diffusion in solids, the major part of the detailed work has by reference to the melting points of tantalum (2996°C), molybdenum (2620°C), niobium (2468°C), and rhodium (1966°C). The diffusion coefficients for the two systems, obtained by least-squares analyses of the data, are well-represented by the equations thus far dealt with relatively low-melting systems. Diffusion studies on the high-melting elements niobium,1 tantalum,2,3 and tungsten4'5 have been limited to polycrystalline material, for which data interpretation and theoretical analysis are sometimes difficult. Only recently, a study has been made with single-crystal molybdenum.6 The present work deals with the measurement of self-diffusion in single-crystal tungsten at temperatures approaching the melting point (3410°c).7 Since the method chosen for producing the radioactive tracer layer-bombardment with deuterons—produced detectable isotopes of rhenium as well as of tungsten, the diffusion of rhenium was measured also.

Jan 1, 1965

By William L. Fink

Nickel is used as an alloying element in several complex commercial aluminum alloys, among which are found some very interesting properties, such as relatively high strength at elevated temperatures, relatively low coefficient of expansion, the absence of permanent growth, ability to take a good polish, and a bright, pleasing as-cast surface. For that reason the aluminum-nickel system was included in the list of binary aluminum systems that are being studied as a preparation for the investigation of more complex commercial alloys. This paper is the fifteenth of a series from the Research Laboratories of the Aluminum Company of America reporting the results of investigations of equilibrium relations in aluminum-base alloys of high purity. The aluminum-nickel equilibrium diagram from 0 to 18 per cent nickel was determined, using the purest material available. Previous Investigations The entire aluminum-nickel system was studied thermally and microscopically by Gwyer.1 At the aluminum end of the system he found the intermetallic compound NiA13. He found a eutectic at 6 per cent nickel with a melting point of 630" C. A slight thermal arrest, which he could not explain, was also noted in alloys from 2.5 per cent to 41.9 per cent nickel at 550" C. Bingham and Haughton,2 in a later investigation of alloys of aluminum with copper and nickel found the eutectic concentration of the binary aluminum-nickel system at about 5.3 per cent nickel. The melting point of the eutectic was about 633" C., or slightly higher than that found by Gwyer. Although the solid solubility of nickel in aluminum could not

Jan 1, 1934

By Albert Phillips

As EARLY As 1824, Haidinger1 described crystals of native copper that were, according to Dana,2 "probably twinned parallel to the octahedral plane and normal to this axis." In 1837, Rose3 very clearly demonstrated that native copper crystals were commonly twinned on the octahedral plane. Lasaulx,4 in 1882, described polysynthetic octahedral twins and stated that enclosed twinning lamellae were observed. Even on crystals formed artificially by. electrolysis, twinning was observed as early as 1886, by Brown.5 Many other descriptions of twinning in native copper and in gold and silver are to be found in the literature, and in every case with which we are acquainted the twinning is conformable to the spinel law; i. e., the octahedral plane is both twinning and composition plane. Metallurgists have long been familiar with the straight-sided bars or bands that commonly occur within the irregularly outlined grains of metallic crystalline aggregates. They are certainly found in nearly all metals of the face-centered cubic type after cold working and annealing. If a specimen showing these bands is rotated, keeping the angle of incidence of the illuminating beam constant, they usually exchange color contrast periodically with their respective matrix crystals. Also slip lines, when produced in these specimens, nearly always show a change in direction upon passing through the bands, giving rise to the "stairway" effect often illustrated in metallurgical textbooks. Apparently the only quantitative observations on bands of this sort were made by Osmond and Cartaud6 on austenitic steel. They selected,

Jan 1, 1928

By Paul Gordon

The distribution coefficient, k, of interest in zone refining is generally defined as the ratio of the solid to the liquid solubilities of one element in another at the normal melting point of the solvent. In practice, distribution coefficients are frequently calculated from solubilities at temperatures well below the melting point of the solvent, e.g., at a eutectic temperature. This is done because of the general lack of accurate data on the liquidus and solidus curves in most phase diagrams. The practice is equivalent to assuming that the liquidus and solidus curves are straight lines in the temperature range between the melting point of the solvent and the temperature at which data for the solubilities are known. It is recognized that the k values so derived may be in serious error; we have found evidence in recent zone-refining operations that a case in point is silicon in aluminum. The phase diagram found in the literature for silicon in aluminum indicates a eutectic on the aluminum-rich side at 12.5 at. pct Si and at 577°C,1 and a solid solubility of silicon in aluminum at this temperature of 1.59 pct.2 It also shows the liquidus and solidus as nearly straight lines from 577°C to the melting point of aluminum (660°C)1,2 The k value obtained from this data is 0.13. This is almost exactly the same as the k value (about 0.14)' obtained in a similar way for copper in aluminum. Yet we have found by mass-spectrograph analyses* of three bars of zone-refined aluminum that copper is efficiently removed from aluminum by zone refining but silicon is not. Two of the three bars of aluminum were zone-refined in our laboratories, the other in the laboratories of AIAG Metals, Inc. The former two bars, designated bars PG2 and PG3, were 30 in. long by 1 in. in diameter during refining; each was processed in a high-purity graphite boat* and kept under refining stage of the process consisted of thirty unidirectional zone traverses at rates of about 1 to 2 in. per hr, with a zone length of 1 to 2 in. At approximately the middle of the refining period a 6-in. piece of the impurity-laden finishing end of the bar* was cut off and replaced with new start- ing material. Following refining, the purest 20-in. section of the bar (obtained by discarding approximately 2 in. of the starting end and 8 in. of the finishing end of the bar) was leveled and then analyzed. The AIAG bar was 16 in. long and about 1.2 in. in diameter; it was purified by eight passes of a 2-in. zone at a rate of 1.6 in. per hr, the bar being contained in a sintered alumina boat lined with loose alumina powder of the highest purity. Data for the silicon and copper contents of the three refined bars are given in Table I. Derived data for the efficiencies of the zone-refining operations are listed in Table 11. It is clear from these two tables that the copper is removed much more efficiently—by a factor of 10 to 50 times—from aluminum during zone refining than is silicon. For example, in bar PG3 the thirty zone passes reduced the copper content from 10 to 0.02 ppm, i.e., by 500 times, whereas the same treatment lowered the silicon content by only a factor of about 16. It seem virtually certain, therefore, that the distribution co efficient, k, for silicon in aluminum is well above that for copper and is very likely not much below unity. This also implies that the solidus line on the aluminum-rich side of the A1-Si phase diagram is very probably appreciably curved near the aluminum melting point since the phase-diagram data indicate such curvature is unlikely in the liquidus.

Jan 1, 1965

By John Sasadi, Karl Heinz Zepter, Leonard Sugin, Roger L. Hulette

Mt. Newman Mining Co. is now completing an expansion program, begun even before initial construction was complete, which will result in the ability to ship up to 35 million tpy of iron ore by early 1973. Located in the Pilbara region of Western Australia, the mine at Mt. Whaleback is about 700 road miles north of Perth and 265 railroad miles south of the port facilities at Port Hedland. Development of the tertiary crushing and screening facilities best illustrates the orderly, but rapid, sequence through which the capacity of the port loading terminal has been expanded. When the present program is completed, crushing and shiploading capability will reach - - 35 million tpy. Operations commenced in 1969 with 3 crusher lines in service; and despite the 5-million annual ton rating, 6.46 million tons of ore were shipped during the first full year of operation. With continuing increase in ore sales, expansion to an annual capacity of 12 million tons was authorized, and installation of two more crusher lines was begun. As a part of this program, provision for installation of a sixth crusher at some future date was included in the planning; but before construction was completed, new ore sales contracts demanded further expansion to an annual rate of 20 million tons, and the sixth crusher line was authorized. The distributing and collecting conveyors had been designed for extension in length and increase in capacity, therefore, conveyor service was provided for the additional crushers with additional belting and hardware only.

Jan 6, 1972

By W. J. Rogers, L. J. Dwiggins, R. O. Williams

THERE has been comparatively little work on the importance of strain rate and temperature as variables in the formation of deformation textures. For this reason the present work was started, the choice of compression being in part that of convenience and in part because of the absence of quantitative data in this area. These do not turn out to be important variables within the range studied which permits the results to be condensed into this note. Samples 1/4 in. in diam and 1/2 in. long were machined from 99.9 pct pure commercial aluminum and recrystallized to a fine grain size. A set of five samples were deformed between a spring-driven weight and an anvil resulting in roughly 20 pct strain each time. The strain rate varied because of decle-ration and shortening of the sample but would average about 10&apos; per min. Deformation at temperatures over the range of -76" to 150°C were obtained by heating or cooling the samples. Complete lubrication could be obtained by oil since the short time of contact did not permit its escape. The samples were compressed to a total true strain of 1.4 to 1.6. A larger sample was prepared similarly with spiral grooves in the ends to hold paraffin which provided essentially complete lubrication. This sam ple was compressed slowly at room temperature at a rate of about 2 per min to a total strain of 1.0. Cylindrical samples were carefully machined from these discs with a radial direction as an axis. They came from the center half of the samples and were roughly 1/16 in. in diam. The samples were etched down 15 pct to remove any surface effects. Diffraction data were then obtained for six different kinds of planes by the use of the Norton technique as applied to a fiber texture. Direct comparison between the raw data failed to reveal any significant difference between any of the samples and consequently the data from only one sample was completely reduced. The particular sample had been deformed at O°C The background was subtracted from the intensity data which were averaged over the four quadrants and then normalized to random. These data were then used to obtain fiber-axis distribution charts as previously described.2 For this sample the (422) plane was also run to assist in this inversion. The final result, Fig. 1, provided a comparable fit to that previously obtained from fiber data. About 85 pct of the material forms an elliptical texture around the <110> direction. The radius (at half height) is 5.5 deg along the (111) boundary and 8 deg along the (100) boundary. The remaining 15 pct forms a ridge running from this texture to near the <311> direction. The regions around the (100) and (111) planes are devoid of material. The earlier qualitative results of ~arrett~ are in complete agreement with the present results. The possibility has been dis-cused that the material around the <311> results from friction between the sample and compression plates.4 The present results are considered proof that such is not the case because of the uniformity of sample deformation and the requirement of axial symmetry before fiber-axis distribution charts can be accurately obtained. Recently results have been obtained to show that strain rate and temperature are important variables in the extrusion of aluminum.5 Perhaps the most important observation was that the partial recrystal-lization occurred even at room temperature. Strain rate was considered to be a factor only in that it produced a temperature change. There are many differences between the two experiments, the most important possibly being that their material was roughly ten times the purity of the present material. The present experiment, however, may not be as definitive as desired in this respect since it has been shown that compressed aluminum recrystallizes without a texture change6 although supplementary

Jan 1, 1961

By W. N. Tanner

THE wire-rope hoisting conditions at the mines of the Anaconda Copper Mining Co. in Butte, Mont., are very severe because of the conditions under which it is necessary to operate. A study was made, in the fall of 1919, for the purpose of changing these conditions in order to obtain longer rope and sheave life. There are at present in Butte, hoisting engines equipped with wire rope as follows: 9 main hoists using flat ropes. 7 main hoists using 1 ½ in. rope. 5 main hoists using 1 ¼ in. rope. 6 shafts using 1 1/8 in. rope. 2 chippy hoists using 1 ¼ in. rope. 9 chippy hoists using 1 1/8 in. rope. 15 shafts using 1 in. rope. 7 shafts using 7/8 in. rope. 1 shaft using ¾ in. rope. In addition, there are a number of sinking engines using 5/8 in., ¾ in., 7/8 in., and 1 in. (15.9, 19, 22, and 25 mm. rope.) The flat ropes run from ½ by 7 ½ in. (12.7 by 190.5 mm.) to ½ by 4 ½ in. (9.5 by 114 mm.) and are used on the older hoisting-engines, which are set comparatively close to the shaft. Because of swelling and moving ground at some of the shafts, these ropes present certain difficulties in operation that are more pronounced than with round ropes; they are, therefore, being superseded by round ropes as newer engines are being installed. They are, however, much more easily inspected and repaired than round ropes.

Jan 2, 1922

By John Goodell

CIVIL engineers seem to number in their ranks more advocates of licensing than are found among the practitioners of other branches of the pro-fession. Licensing was not originated by civil engineers but it was forced upon them in two ways. In the first place, the civil engineering profession has hangers-on like every other profession. The first legislative result of their imperfect accomplishments with which I am familiar occurred in the far West. It was found that early irrigation works were so badly planned in some cases that not only were water rights made very uncertain but considerable sums were invested in structures and ditches which proved inadequate and occasionally complete failures. Water was too valuable to be wasted in that way and money too hard to obtain. In those sections, therefore, laws were passed many years ago which made it obligatory for the design of irrigation works and other structures utilizing water to be made by engineers who had satisfied a board of examiners that they possessed the technical qualifications to plan such works properly. The basic thought on which such laws rest is the same as that on which laws governing the licensing of boiler operators rest, namely, the safety and welfare of the public. While boiler explosions still occur and irrigation works are built which are not wholly satis-factory, these laws have helped the, public, it is gener-ally agreed.

Jan 4, 1922

By Gordon H. Geiger, J. Bruce Wagner

Electrical conductavity and therrnoelectvic nzeasuretnents on synthetic hematite slabs with 0.01 to 0.90 at. pet Ti and with 0.30 at. pet Ca were made. Additions of titanium and of calcium both increased the electronic conductivity with titanium yielding greater n-type behavior and calciurn p-type behavior. Reduction studies of hematite to magnetite in CO-CO2 atmospheres between 600° and 900°C initially exhibited linear kinetics. These linear rates were increased by additions of titanium and decreased by calcium. IN recent years many studies have been reported in the literature on the kinetics of the reduction of hematite and magnetite to iron. In addition, Hansen and Josephl and Schenck and Schultz2 have reported studies on the reduction of hematite to magnetite, the first step in total reduction to iron. In order to evaluate the results of the studies of over-all reduction in terms of the actual mechanism of the reaction and to define further the important factors in the rate- controlling mechanism of the magnetic roasting reaction, the following experiments were undertaken. Specimens of undoped hematite and hematite containing titanium or calcium in solution as doping agents were reduced to magnetite in CO-CO2 mixtures. In addition, electrical-conductivity measurements were correlated with the reduction kinetics using concepts of defect solid-state chemistry. EXPERIMENTAL Fisher certified Fe2O3 powder was used to make specimens for both the electrical and kinetic studies (see Table I for analysis). Doping with titanium and calcium was accomplished by adding TiO2 and CaO powders to the Fe2O3 powder. The powders were mixed in a Waring blender for minimum times of 1/2 hr. Satisfactory blending was achieved based on comparison of analyses of individual specimens af- ter reduction. The specimens were formed in a steel die using opposed punches with a rectangular opening 10.0 by 40.0 mm. The Fe2O3-TiO, platelets were pressed cold at 16,000 psi. They were sintered for approximately 16 hr at 1075°C in air, in accordance with information in the literature3, 4 on the time and temperature needed to obtain solution of the titanium in the hematite. The Fe2O3-CaO mixtures were first cold-pressed at 20,000 psi and sintered for 3 hr at 1225°C to insure solution of CaO. This material was then ground to -325 mesh in a 6-in. ball mill and the resulting powder was used to make platelets in the same manner as above. The sintered platelets were usually between 1/16 and 1/8 in. thick. They were ground on a carborundum wheel and polished on 2/0 paper. Typical dimensions of the kinetic-study specimens were 1.6 by 0.8 by 0.05 cm, and a typical weight was 0.3 g. Conductivity and thermoelectric specimens were approximately the same size, but were subjected to further sintering in order to ensure maximum densification. Finally, all specimens were measured to the nearest 0.0005 in. and weighed on a Mettler H-15 balance to the nearest 0.0001 g and the density calculated. The average density of the specimens used for the reduction studies was 4.87 g per cc, or 7.1 pet total porosity. The standard deviation ranged from 0.14 to 0.063 g per cc within a composition group. In the present study, the apparent surface area as measured with a micrometer was taken as the true surface area. The chemical analyses for calcium and for titanium within a group showed maximum variations of 50.04 pet from the average values used in Figs. 9 and 11. In order to suspend the specimen from the balance for the kinetic studies, a hole, 0.03 in. in

Jan 1, 1965

By C. D. Stahl, R. Sandrea

This investigation was made to evaluate the comparative effects of the viscosity and the phase behavior of the buffer fluid in the composite solvent displacement of Bradford crude from waterflooded sandstone cores. Buffer slugs of propane, naphtha and other refined hydrocarbons exbihiting increasingly favorable viscosity ratios and decreasing solubility relationships, respectively, with Bradford crude, were used in long Berea sandstone cores. The secondary slug was isopropyl alcohol. The results indicate that higher oil recoveries are obtained for increasingly favorable phase relationships even when these are accompanied by unfavorable viscosity ratios within the range studied. Moreover, when propane is used as a buffer slug with an adverse viscosity ratio of 36, it gives higher oil recoveries than at a similar size slug of an any1 alcohol having a viscosity ratio of 1.09. The investigation was extended to the study of the effect of flooding rate on oil recovery. Residual Bradford crude was displaced from a 6-ft Berea sandstone core at rates varying from 0.3 to 30 ft/ day. The results show that as flooding rates were increased above or decreased below a minimum range of 1 to 2 ft /day, displacement efficiency increased considerably. INTRODUCTION In recent years, the alcohol slug process as a means of tertiary recovery has been the subject of many investigations. Gatlin and Slobod showed the advantages of the combination solvent slugs over the previous single-slug process.1 The combination slugs require less total slug material to obtain similar oil recoveries. The basic combination process involves injecting a primary or buffer solvent which is preferentially oleophilic, followed in turn by a water-driven slug of isopropyl alcohol. This procedure ensures that the buffer slug, which is miscible only with the reservoir oil, displaces and replaces the oil and is in turn displaced, together with the water, by the isopropyl alcohol slug miscible with both fluids. Likewise, for those reservoir oils that show some degree of phase incompatibility with isopropyl alcohol, as does Bradford crude, a proper buffer solvent can artificially make the alcohol process technically feasible. From an economic standpoint, propane or LPG would be the most appropriate primary solvent to be used in the field; however, Taber, et a12 have indicated that the alcohol process becomes highly inefficient in the displacement of light hydrocarbons because of the entrapment of these hydrocarbons during the stabilized bank formation. Moreover, since materials such as propane have such low viscosities, adverse viscosity ratios with most reservoir oils would be penerated, thereby possibly further reducing the efficiency of the buffer solvent. This paper presents the results of an experimental study of the comparative effects of viscosity ratio and phase relationships on the displacement efficiency of Bradford crude by means of dual solvents. The work was extended to include the effect of flooding rate on oil recovery. Rates within the range of field and laboratory values were used. EXPERIMENTAL PROCEDURE APPARATUS The porous media used in this study consisted of two 10-ft and one 6-ft Berea sandstone cores, 3-in. in diameter. These were cast in galvanized steel pipe of 31/2-in. ID and the annulus was filled with Armstrong cement. The 10-ft cores were assembled by connecting two 5-ft units, which were joined together by 8-in. steel flanges fitted to the pipe. Intimate contact between the two sections was obtained by inserting a thin disk of the same sandstone between the core faces. The outlet and inlet ends of the cores were covered with threaded pipe caps. The injected fluid was gravity fed to two variable-rate positive-displacement pumps. The fluids were filtered before entering the core and the effluent was collected in an automatic fraction collector and

Jan 1, 1966

By P. B. Mee

The secondary re crystallization behavior of two vacuum-melted, nominally 3 pct Si-Fe alloys has been studied, one alloy being produced from pure electrolytic iron and semiconductor-grade silicon and the other from commercial-purity hot band. The vacuum-melted and vacuum-remelted alloys were found to develop {110}(hhl) and {lll)(hkl), respectively, on annealing in high vacuum and {100}(0kl) and {11l}(hkl), respectively on annealing in pure hydrogen of dew point, < — 60°C. H2S doping of the hydrogen or annealing in commercial argon was found to effect a reversal for the vacuum-remelted alloy from (111) to (100) secondary recrys-tallization, while prolonged vacuum annealing at 2 x 10-6 Tow resulted in a tertiary re crystallization from (111} to (110). The growth selection of the {lll}(hkl) component was found to be governed predominantly by the {111}/planar misorientation, the maximum deviation of the resulting secondaries being 5 deg. It is considered that the driving force for {111}(hkl) secondary recrystallization arises from the preferential lowering of ?111, possibly by phosphorus or nitrogen diffusion, just as oxygen and sulfur under certain conditions have been found to preferentially lower ?100. When heavily cold-rolled metals are annealed at high temperatures, primary recrystallization usually occurs rapidly and may be followed by considerable grain growth. However, in the presence of a fine dispersion of inclusions1"3 or with a strong matrix preferred orientation4&apos;&apos; the matrix may be stabilized and a secondary recrystallization may then be effected. Also, in vacuum-melted Si-Fe it has been shown possible to develop {100}(001) and {110}(001)6 surface energy driven secondary recrystallization textures. Further, it has been found that, on annealing very pure metals, grain growth normally ceases when a grain size approximately twice the strip thickness is acquired, due to the formation of V-shaped thermal grooves which result in an equilibrium being set up between surface and grain boundary stresses. If, however, a surface energy difference ??s, exists between adjacent grains (of the order of a few percent of the grain boundary energy ?b), then according to Mullins8 a secondary recrystallization may be effected, since the grains having lowest ?s would grow at the expense of their higher-energy neighbors. For clean bee metal surfaces ?110 should be lowest; however, for 3 pct Fe-Si (100) secondary structures have frequently been developed and have been attributed by Walter and Dunn9 to an alteration of the relative surface energies due to the preferential chemisorption of oxygen on (100) planes. Kohler,10 however, indicated that this reversal may be achieved by employing minute quantities of highly polar compounds in the annealing atmosphere, i.e., sulfur compounds, in par- ticular H2S being beneficial in (100) growth. This work has been verified by Kramer" using {100)/{110} bicrystals, while Mager12 demonstrated the importance of sulfur diffusion within the strip. Detert13 has intimated that carbon may be responsible for the preferential lowering of ?110 although no direct evidence has appeared yet to support this supposition. It must , be appreciated that the above-mentioned examples of surface energy driven secondary recrystallization were obtained with very pure vacuum-melted materials with oxygen contents (which is now known to be a critical factor") less than 35 ppm. During the course of a textural study on Si-Fe it has been found that under certain conditions (111) secondary recrystallization can be obtained by what is believed to be a surface energy growth selection mechanism. The purpose of the present paper is to briefly describe this result and to try and postulate the possible causes. EXPERIMENTAL Two vacuum-induction-melted, nominally 3 pct Si-Fe alloys were produced, one from pure electrolytic iron and semiconductor-grade silicon designated A and the other from commercial-purity hot band, designated B.

Jan 1, 1969

By W. H. Emmons

IN 1922 Morey made a series of experiments in which he observed the cooling of a molten system containing H20, 9.1 per cent; K20, 17.3 per cent and Si02, 73.6 per cent. This system was confined in a bomb; it was fluid at 500° C. and exerted no vapor pressure. In cooling to 420° C. a large part of it crystallized and at that temperature much of the water had separated from the crystals and remained as steam, which built up a pressure of 4998 lb. per sq. in., a force sufficient to lift nearly one mile of granite.1 If granite, cooling at 600°, expels vapor in the process of crystalliza-tion it is reasonable to suppose that a considerably greater vapor pressure would result, and it is thought that the vapor expelled from crystallizing granitic batholiths probably has a pressure sufficient to lift two or three miles of granite. This vapor, collecting near the tops of cupolas of batholiths, is believed to exert sufficient pressure to fracture the hoods and roofs of batholiths above the cupolas. If that is true, one would expect to find that the fracture systems above cupolas are arranged in patterns that depend in part on the shapes of the cupolas. The mechanics of the situation seem to require that conical cupolas should have radial fracture patterns, that bluntly rounded cupolas should have fracture systems that are either irregular or rudely conjugated in plan, and that elongated stocks or cupolas should have fracture systems in which the fractures lie nearly parallel to the direction of the elongation of the cupolas.

Jan 1, 1934

By J. Lyndon Rosenblad

The strength of a jointed-rock mass is not well-understood. It is believed, however, that the behavior of a rock mass is governed by both the intact rock properties and the properties of the discontinuities. Rock research in the past has been concentrated on the determination of intact rock properties. Several studies are presently underway which should provide more insight into the properties of the discontinuities. Few research programs, however, have been undertaken with the intent of studying the composite rock mass behavior where either the intact rock strength or the properties of the discontinuities may control failure. There are three approaches available for studying the behavior of a rock mass, namely, field studies, mathematical models (finite element), and geomechanical models. A geomechanical model has been developed in this study where the strength and failure modes of a model rock mass are studied as a function of intact block geometry, joint orientation, joint properties, and confining pressure. The objective of this study is to gain some insight into the parameters that govern the behavior of a rock mass, which parameters are most important, and when these parameters control. This chapter describes only one phase of the study, the development of equipment for use with the rock-blocks model. The models being tested are approximately 22 x 22 x 6-in. The size varies slightly depending upon the joint orientation used. The equipment developed includes model material molds, reaction frames, loading apparatus, measuring and recording instrumentation, and other accessory equipment pertinent to the operation of a successful study. The usual problems in equipment development, such as uniformity of load application, loading capabilities, and reaction capacities are all

Jan 1, 1970

By H. M. Howe

On commencing the construction of the Orford Company&apos;s copper smelting works, at Bergen Point, N. J., I endeavored to convince our President, Mr. W. E. C. Eustis, by actual tests, that at the pressure of from 15 to 18 ounces per square inch, employed by us in smelting, less power was consumed in delivering a unit of blast by a Baker blower than by a fan blower. I attempted to prove this in the following manner: Across the mouth of a No. 5) Baker blower I firmly fastened a board with two round holes, 6 inches in diameter, cut in it. The board was fastened so tightly that no air could escape except through the holes. I then drove the blower at several differerent speeds, observing the pressure at which the air excaped through the two openings for each different speed of the blower, and also indicating the engine, whose only work at that time was to drive the blower. From this I calculated the quantity of power required to deliver, with a Baker blower, sufficient air to keep the pressure at a given point, while it escaped freely through the two six-inch apertures into the open air; or, in other words, to deliver air at a given pressure through these two openings. From the total power so consumed it was, of course, necessary to deduct the power which was required to drive the engine itself. This was ascertained by removing from the engine the belt which drove the blower, and then noting the quantity of power consumed in simply turning the engine over without any

Jan 1, 1882

By H. H. Stout

IN the early fall of 1925, the writer was conducting, in the Ledoux and Co. labora-tory, New York, experiments directed to-ward ascertaining the effect on its impurity content when cathode copper was subjected to a current of various gases at an elevated temperature below the melting point, The apparatus consisted of a vertical 1-in. dia. silica tube about 12 in. long, heated on the outside, The cathodes were broken to pass a8-in. mesh, and a current of various differ-ent gases was passed up through a 4-in, long column of these loose cathode particles in the vertical tube furnace. Temperature was maintained to i500° to 1600°F. and the gas treatments lasted from 3 to 6 hr, The writer observed that whenever reducing gas (H2 or CO) was used, these cathode par-ticles stuck together at points of contact with each other. The cohesion was so marked and tenacious that an examination was made of the fractured surfaces, when cathode particles were broken from the cluster. Crystal growth was always found to have taken place across the surfaces where separate particles were in contact, but only after all oxides, sulphates, etc, had been completely removed. The idea of a possible new process was then conceived and was disclosed to A. M. Smoot (V. P. Ledoux and Co.) with intent to obtain his views. The first conception as given Smoot was "to gas-clean broken cathodes, put them in an extrusion press, solidify and extrude them at around 1500°F," Smoot&apos;s reaction, after a few moments considera-tion, was, "It looks perfectly all right to me."

Jan 1, 1940

By J. F. Myers

THE Tennessee Copper Company&apos;s operations are in the Ducktown Basin, in the extreme southeast corner of Tennessee. The ore is of the heavy sulphide type, the predominating sulphides being pyrite, pyr-rhotite, chalcopyrite and sphalerite. The gangue is a micaceous schist, with varying amounts of free quartz. The mining operation develops two classes of ore, each of which is concentrated by the flotation process in separate mills. Table 1 shows a typical analysis of the ore treated in each mill. TABLE 1.-Typical Analysis of Ore Treated Composition, Per Cent Mill Tons Capacity Cu Fe S Zn London 1,350 1.41 28.4 20.2 1.10 Isabella 850 0.69 44.7 31.6 0.31 LONDON MILL The London mill was built in 1922, with a capacity of 400 tons per day. This was gradually increased to 600 tons by 1926, to 900 tons in 1928, and to 1350 tons in 1938. Fig. 1 shows the crushing and grinding flowsheet in 1928, when the capacity was 900 tons; Fig. 2, the crushing and grinding flowsheet that was developed by 1938, for the treatment of 1350 tons per day. A comparison of these flowsheets reveals that this increase in tonnage, with a subsequent improved operation, was accom-plished with identically the same major equipment. Improving a concentrator&apos;s capacity, metallurgical results, and costs as time goes by is a commonplace practice, and is accomplished in various ways, depending upon the local conditions. The reason for presenting the data of how this was accomplished in the mills of the Tennessee Copper Co. is that a fast-running rod mill plays such an interesting role

Jan 1, 1940

By R. J. Jackson, D. E. Williams, W. L. Larsen

The phase diagram of the Ta-Zr system is presented with a discussion of the methods used in its determination. The solidus contains a minimum at 1820°C near 25 wt pet Ta. A complete solid solution exists at elevated temperatures between tantalum and ß zirconium. This solid solution decomposes monotectoidally at 800°C and 12 wt pet Ta. The maximum solubility of tantalum in a zirconium is slightly less than 2 wt pet, and decreases with decreasing temperature. The solubility of zirconium in tantalum is 5 wt pet at the monotectoid temperature and about 2 wt pet at room temperature. THIS investigation was part of a program of research on refractory metal alloy systems having potential application in nuclear reactor technology. Preliminary prop-ess has been reported in the Ames Laboratory annual research reports.l Most of the previously reported work on the Ta-Zr alloy system consisted of partial phase diagram investigations and the determination of the mechanical properties of the zirconium-rich alloys. Anderson eta1.2 studied alloys containing up to 30 wt pet Ta as part of an investigation of several zirconium alloy systems. These investigators also determined some of the mechanical properties of the alloys at room temperature and 650°C. In a discussion of Anderson&apos;s work, Pfei13 suggested that the bright phase in the microstructures of the intermediate alloys is a tantalum-rich solid solution or an intermediate phase in a matrix of ß zirconium solid solution. Litton,4 Keeler,5 and Chubb6 determined the mechanical properties of zirconium-rich alloys at ambient and elevated temperatures. Van Thyne and McPherson7 reported the tensile properties

Jan 1, 1962

By Albert Sauveur

Jan 1, 1924

By Albert Sauveur

Jan 1, 1924

By Seymour G. Epstein

Using a modified capillary-reservoir technique, electromigration of dilute solutions of silver in liquid bismuth has been measured with relatively good precision. The effects of experiment duration, temperature. current density, and silver concentration have been investigated. Chemical diffusion coefficients of silver in liquid bismuth were also measured at temperatures ranging from 300°to 600°C. The effective valence of silver in bismuth was calculated as a function of temperature from a comparison of electric mobilities and diffusion coefficients. In an alloy containing 1 wt pct Ag, the electric mobility of silver increased from 1.65 x X sq cm per v-sec at 300°C to 2.38 x 10-4at 600°C; the diffusion coefficient in-creased from 3.0 to 17.5 x 10-5 sq cm per sec over the same temperature range. Calculated values of effective valence decreased from 0.28 at 300°C to 0.10 at 600°c. ALTHOUGH there has been considerable progress in the theoretical treatment of electron-transport properties in liquid metals, the mechanisms of mass-transport phenomena in liquid metals are still not clearly understood. This is especially true for the case of electro migration, alternatively termed elec-trotransport or electrodiffusion, which is mass transport induced by an applied electric field. A thorough knowledge of the mechanisms governing electromigration will considerably aid in understanding the electronic state of an impurity atom in a liquid metal. Electromigration has been long observed and studied in liquid metals and alloys. However, no satisfactory theory to explain the observed effects has been developed. The disparity in the present theoretical treatments, summarized by Verhoeven,1 has been attributed to the difficulty in describing the momentum transfer between electrons and ions and to the lack of precise measurements in liquid metals, especially at elevated temperatures. Prior to the last decade most of the electromigration studies were qualitative, in that only the direction of migration of alloy constituents was determined with any degree of reliability. These results have been summarized by schwarz,2 who was able to measure the electric mobility of several elements in mercury. More recently electromigration in liquid metals has been measured by a variety of techniques, with a varying degree of success. Mangelsdorf3,4 made precise measurements on dilute amalgams at room temperature, using a technique relating changes in composition to changes in alloy resistivity, but was unable to make measurements at elevated temperatures. Using a modification of this technique, Verhoeven and Hucke5 measured electromigration and resistivities in liquid Bi-Sn alloys. However, the resistivity technique is not sensitive to small composition changes and is impractical for very dilute alloys. Verhoeven and Hucke6 also measured electromigration of several solutes in liquid bismuth by adapting the capillary-reservoir method for determining diffusion coefficients in liquids. The reported precision of these measurements was poor, however, primarily due to the large uncertainties in the chemical analyses to determine concentration changes. Belashchenko7 has summarized the recent Russian investigations of electromigration, many of which, however, are of questionable accuracy. The present study was initiated to develop an experimental technique which would be both versatile and sufficiently sensitive to yield precise measurements of electromigration of solutes in dilute metal alloys at elevated temperatures. Using this technique, a comprehensive study of silver in liquid bismuth was made to determine the effects of experimental variables on the apparent electric mobilities. Chemical diffusion coefficients of silver in liquid bismuth were also measured over the same temperature range for comparison with the electromigration data. EXPERIMENTAL TECHNIQUE Electromigration Measurements. Electromigration of silver in liquid bismuth was measured by the capillary-reservoir technique, similar to that used by Verhoeven and Hucke,6 but modified to yield more

Jan 1, 1967