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By P. R. Sahm, T. V. Pruss

Mixtures of fine GaSb and Gds as well as preal-loyed GaSbl,As, powders were hot-pressed at 690°C and 25,000 psi. Dense alloys with compositional gradients of less than 5 pct were obtained from mixtures containing about 20 mol pct GaAs. For x < 0.2, there were increasing compositional gradients, and for x > 0.2 a GaAs-rich second phase appeared in the microstructure. Densification as well as alloying wlechanisms were enhanced by dissociation and, possibly, oxidation reactions of the powders. Densification of coarse prealloyed material, however, primarily depended on plastic flow phenomena and required temperatures just below solidus and pressures of 50,000 psi Thermal and electrical properties were measured. Although in no case was the figure of merit of melt growth materials approached closer than to within 25 pct, the better overall thermoelectric properties were found in coarse-grained, prealloyed materzals which had been compacted to near theoretical density and where grain regrowth had been induced. Similar results are believed to hold in other binary 111-V compound systems if processed under similar conditions. The densification of unalloyed GaSb powders during pressure sintering (= hot pressing) was shown to depend strongly on powder particle size.&apos; Fine powders displayed a "liquid skin effect" that enhanced compaction through the presence of liquid gallium, whereas coarse powders compacted predominantly by plastic flow. The liquid skin effect, in particular, appeared attractive for alloying GaSb with other, higher-melting, III-V compounds, and to densify these in a one-step operation. This is of special interest in the case of III-V compound alloys as the conventional techniques of melt growth or long-time annealing of powders2 is very time-consuming, especially in cases where a large separation of liquidus and solidus can be expected, such as in GaSbl alloys.2 It was felt that experimentation with this system, a particularly unfavorable example, would allow us to extrapolate to several other, more favorable, cases. Uses of Ill-V alloys are most evident in thermoelectric energy conversion devices.&apos; For this reason certain thermal and electrical properties were measured and compared to those of melt-grown material and to hot-pressed prealloyed powders. EXPERIMENTAL PROCEDURE The pressure-sintering apparatus has been previously described.&apos; Using this equipment, both powder mixtures of GaSb with GaAs and prealloyed GaSbl-,As, powders were hot-pressed. The mixtures were pre- pared from cast GaSb and melt-grown GaAs. The prealloyed material was obtained from stoichiometric melts, initially heated to 1200°C in an evacuated quartz ampoule, and then annealed in the solidus-liquidus interval. A typical annealing cycle consisted of a heating to 850°C (1 hr), extended successive annealing at 750°C (65 hr), and slow stepwise cooling (25 hr) to below solidus. The GaSb, GaAs, and GaSbl-,As, materials were ground in a vibrational mill to particle sizes below 500 . A jet mill reduced these further where necessary. Fine powders were analyzed by Coulter counting for their size distribution. Average sizes by volume were calculated from the data. Mixing of the powders, where necessary, was carried out through rapid vibrational motion. The hot-pressing operation consisted of a degassing period of 15 hr, in most cases at 690°C, followed by several hours of compression, normally 25,000 psi at 690°C for powder mixtures and 50,000 psi at 710°C for prealloyed powders. The chemical compositions were confirmed by X-ray fluorescence analysis. To estimate the degree of solid solution achieved, lattice parameters were determined and interpreted according to Vegard&apos;s rule. In addition, optical microscopy helped to correlate the relative amounts of the phases present as well as the degree of porosity to the measured density. To reveal grain boundaries, polished surfaces were etched4 with H 2 O:H 2 O:HCl = 2:l:l. In several cases microscopic concentration gradients were monitored by electron-probe analysis-. RESULTS AND DISCUSSION Alloying and Densification of GaSn-GaAs Powder Mixtures. After preliminary experiments showed that no appreciable alloying took place in mixtures of coarse GaSb (22.5 p) and fine GaAs (2.5 p) powders, hot pressing of mixtures was confined to fine powders only (3.1 and 2.4 p, respectively). Alloying and densification apparently occurred simultaneously with a grain regrowth mechanism which depended on the presence of a liquid phase.&apos; The liquid phase was provided by the dissociation of GasbS particles into liquid gallium and antimony above 555°C. This not only enhanced grain regrowth and densification, as in unalloyed GaSb,&apos; but took on additional importance here for the alloying process. Alloying was speeded up by the resulting liquid-solid interaction as compared to the very slow solid-state diffusion process normally expected at these temperatures.&apos; The results obtained with a series of powder mixtures have been compiled in Table I. It is seen that for mixtures with less than 20 mol pct GaAs, x < 0.2, the compositional ranges increased and for x > 0.2 a GaAs-rich phase and free antimony appeared in the microstructure in sizable amounts.

Jan 1, 1968

By R. F. Mehl, W. Batz, C. Wells

L. S. Darken—It is indeed gratifying to find that the results of the two different methods here reported are in substantial agreement with each other and with the earlier work1 of two of the authors. Dr. R. P. Smith, of our laboratory, has been conducting some experiments at 1000°C to determine the diffusivity of carbon in austenite by a third method— the steady state method. This work, which will soon be reported, is far enough advanced that we can say it is in substantial agreement with that of the present authors. The only disparity which might be considered significant is in the high-carbon region, where we find that the diffusivity rises a little less steeply than indicated in fig. 8. F. E. Harris—The authors have presented an impressive arrangement of data concerning the diffusion of carbon in austenite. Of particular interest is the compilation, table IV, which is repeated in col. B of table V for direct comparison with values (col. A. table V) from a formulation using a single Q value of 31,000 cal as the activation energy for diffusion. This comparatively simple formulation has been used quite successfully in the practical application of calculating the carbon added (or removed) through the face in carburizing and decarburizing experiments, where the face concentrations are held quite constant for known times and temperatures. Literally hundreds of tests have been so checked where the computed and experimental values have varied by less than 5 pct. For higher temperatures, where proper carburizing data are hard to obtain, the diffusion couple is treated as a decarburization of the high-concentration bar and as a carburization of the low-carbon member. The analysis has been limited to a maximum of 1.40 wt pct carbon. The agreement between cols. A and B in table V may be considered fair, if a liberal viewpoint is taken. The use of a diffusion couple has one serious drawback, in that comparatively small amounts of carbon pass through planes of concentration close to those of the initial high-carbon and low-carbon members, and hence small errors become important. In addition to the sensitivity at these high and low concentrations.

Jan 1, 1951

By John A. Meech, J. G. Paterson

Activated carbon is a strong adsorbent for amyl xanthate, capable of removing from solution up to a quarter of its own weight in xanthate. In selective flotation system where depression is unstable, separation efficiency increases with activated carbon additions. The improvements observed are brought about by two mechanisms. First, by removing stripped and residual collector ions from solution, competition between depressant and xanthate is reduced and depression is stabilized. In addition, the texture of the froth phase at high pine oil concentrations is modified by activated carbon such that better drainage between the air bubbles takes place, alleviating the mechanical entrapment of depressed mineral particles. In treating a bulk copper/lead concentrate produced from GECO ore, selectively between galena and chalcopyrite is increased when activated carbon is used. Although the rate of flotation of galena is marginally lowered by activated carbon, a small extension in the duration of flotation allows the lead recovery to increase by 19% at the same recovery of copper. An addition rate of 0.75 kg/ton (1.5 lb/st) of bulk concentrate is suggested as optimum from this testwork. However, the actual level used in the mill is dependent upon the residual concentrations of collector and frother in the bulk concentrate pulp.

Jan 1, 1979

By HUGH E. McKinstry

OPENING the sessions of the Mining Geology Committee, the program on postwar mineral controls drew a larger attendance than any other session of the entire meeting. In view of its general interest, the papers of this session, or a substantial portion of them, are printed elsewhere in this issue. Whether control of mineral resources can help to promote peace, how controls could be applied and to whom, are questions so far-reaching that naturally no pat answer was agreed upon. In fact the discussion took on something of the flavor of a debate between those who favor strict control and those who felt that attempting to ration nations in peacetime would defeat its own ends. Discussion from the floor emphasized the difficulties in administering any international control and the $64 question, that no one cared to answer, asked by a courageous young lady who was induced to mount the rostrum for the purpose, was whether the United Nations should exchange mineral controllers to police each other.

Jan 1, 1944

THE progress in lead smelting practice in the United States during 1930 has been along previously defined lines. Since most of the material treated is high-grade concentrate relatively high in zinc, practically all the plants have been forced to adopt double sintering. This generally results in there being&apos; no matte fall, and most of the copper in the charge is recovered in the furnace dross. The furnace dross is . smelted with. scrap iron and flux .in small reverberatories, giving a shipping matte or speiss high in copper and low in lead. Details of this reverberatory. furnace practice vary at the different plants. There is a decided tendency toward moreintensive filtration of blast- furnace and sinter fume. Bag capacity has been in- creased by using higher pressures and more frequent shaking.

Jan 1, 1931

By Mark Malamphy

DURING colonial times, Brazil was famous for the richness of her alluvial gold deposits. Paul Ferrand has estimated that the gold produced during the period from 1700 to 1820 was the equivalent of some 64 million pounds sterling. Since that time, most of the more prolific alluvial deposits have been exhausted. A few gold mines are still func-tioning, notably the Morro Velho mine, which is one of the deepest mines in the world. Today, the gold production of Brazil is insignificant when compared with world figures, but there are still many gold-bearing regions and it is probable that in at least some of them profitable returns would result from an exploitation program taking advantage of all the most modern innovations in gold mining and ore treatment on a large scale. In order to demonstrate the value of some of these abandoned pros-pects and stir up interest in increasing the national gold production, the government has stimulated research. Experimental plants have been and are being established in various places, and tests on large quantities of ores are being carried out on a semicommercial basis. The Geological Survey of the State of Minas Geraes is very active in this line and the Federal Institution is also showing an increased interest in the matter. One of the lesser known gold-bearing regions of Brazil is in the vicinity of Lavras, in the State of Rio Grande do Sul. Gold was first reported from this region in the early part of the nineteenth century. In 1811, D. João VI sent an experienced prospector from Minas Geraes to investi-gate the validity of the reports. According to the reports of Baron

Jan 1, 1934

By G. M. Wiles

The increasing number of problems of the modem mine manager has led the author to discuss the art of management. He lists the principles concerning selection of personnel, exploitation and development, new equipment, process improvements, new processes, maintenance, operating cost data and public relations. Application of the principles to problems of mine startup, operation and rehabilitation are described. Since D. C. Jackling was famous for his adeptness at organizing and training teams of operating personnel, the subject of mine management is particularly appropriate for a Jackling Lecture. In fact, it is doubly appropriate because in very basic ways Jackling&apos;s career changed the nature of the tasks and challenges facing a mine manager. Management of mines, of course, is the art of finding and winning minerals economically from the earth&apos;s crust, and it involves the use of all the engineering sciences. But also of prime importance is a skill which is not yet a science - the area of management often referred to as human engineering. Since expenditures on staff and labor may well involve more than 50% of the direct costs of operating a mine, ability at human engineering is just as important as the ability to plan and put into effect the most efficient operating procedures. In addition to his ability to select and train operating personnel, Jackling possessed, to a degree unmatched by many of his contemporaries, broad, analytical powers covering both the economics and operating phases of large scale mineral extraction. His breadth of vision found its greatest expression at the time he analyzed the Utah copper deposit. Fortunately, Messrs. Penrose and Gemmell had enough faith in his analyses to furnish the capital needed to begin operations. The result, as is well known to all of you, was Kennecott&apos;s lucrative Utah copper mine — and the beginning of the open pit porphyry copper era. The Utah copper mine, and Jackling&apos;s subsequent similar successes in Arizona, New Mexico and Nevada, had one thing in common —all of these large porphyry deposits were worthless until open pit, large daily tonnage schemes were developed for their exploitation. The successful development of such schemes made vast new mineral resources available for economic exploitation. But at the same time, the trend away from smaller high grade operations in favor of the far more complicated operations required to handle large deposits of low grade ore have greatly altered a mine manager&apos;s problems. We are all familiar with the saying "mines make managers." There is still some truth in this statement, but far less than there used to be in the days when high grade properties were the rule rather than the exception. When high grade orebodies prevailed, many managers, superficially at least, could not make a mistake because the profits of their mines

Jan 1, 1962

By W. J. Taylor

FURNACE-MEN who have not taken advantage of the use of dynamite in certain blast-furnace troubles, as explained by Mr. Witherbee in his valuable papers read before the Institute some years since, cannot appreciate the quick relief and great advantage that may be derived at times from its judicious employment. Before giving my experience in the use of high explosives in blastfurnace troubles of certain kinds, I will record a method I have used with marked success in " blowing down." Had I not understood, however, the use of powder, I would have " salamandered " effectually the first time I tried it. Early in my straight-furnace experiments, last summer, at the Chester, N. J., Furnace, I wanted to blow down to within 3 or 4 feet of the tuyeres. To do this with a down-comer not lined, and without putting in any limestone to keep the gases cool enough to do no harm, was not an easy task. We could keep the bell and hopper cool by filling them with water, say 12 inches deep; but before we got the stock down 15 or 20 feet the pyrometer in the gas-flue on top mas up to 1300°, and the clowncomer was red-hot, with the heat still rising. In this emergency my assistant, Mr. N. M. Langdon, urged the trial of a plan lie had often advocated, viz., the introduction of water in some way under the bell in the proper quantity, in order that its evaporation might absorb and reduce the heat of the escaping gases to a point where it would not do any harm. He thought the bell

Jan 1, 1885

By George I. Adams

Peru is divided into three regions—the coast, the ~ierra, or high mountainous region, and the " montaiia," or forest region of the Amazon basin. The Coast.—The coast is an arid region. No rain falls excepting in the extreme northern part, which borders the Gulf of Guayaquil. There is, however, a slight precipitation in the form of mist (gcirua), which occurs on the coast hills during the so-called winter months. The aridity of the coast is due principally to the antarctic, or Humboldt, ocean-current, which, being cold and having a temperature lower than that of the land, absorbs rather than produces vapors. The coast mists occur during the season when the land is relatively cold. N ear the Gulf of Guayaquil the antarctic current diverges from the coast, so that in the Tumbes valley and adjacent country the conditions in the summer months are such as prodnce rains. In the remaining valleys of the coast, agriculture is made possible only by means of irrigation, and is accordingly very limited in extent, although rich and varied. In the northern and south-central portions of the coast, plains extend inland from the sea, while in the southern part there is a coastal plain separated from the Pacific by a range of coast hills. Between the northern and south-central plains, as well as between the south-central and southern, the foothills of the sierra descend to the seacoast. The Sierra.—The sierra embraces the high land dominated by the lofty cordilleras of the Andes. In the southern part of Peru there are two cordilleras, the western and the eastern, which enter from Chile and Bolivia respectively, and inclose between them the Titicaca Lake basin. To the north of Lake Titicaca these cordilleras unite in the knot of Vilcanota, south of Cuzco. From this knot three cordilleras, known as the western, the central, and the eastern, extend to the northward, reuniting in the

Jan 1, 1909

By R. Maddin

IN analyzing the relation between the orientation of new grains and that of the deformed matrix of axially extended and recrystallized single crystals of face-centered cubic metals, a two-stage rotation process" is generally used where the first rotation is made in order to account for an "adjustment of orientation to the environment of strain."&apos; It has been argued that in spite of the difference of orientation, which may amount to as much as 12" (in a brass),&apos; between the octahedral plane as observed in the parent lattice and in the recrystallized grain, it is believed to be a common plane in the sense that it constituted the nucleus in the parent strained crystal from which the new grain grew.&apos; A possible source of the deviation in orientations of a common pole in the new grain and that of the deformed single crystal matrix from which it has grown may be found in the distribution of strain resulting from the plastic deformation. It might be expected in view of the incongruent nature of shear&apos; that the perfection of the octahedral plane along which glide has occurred is disrupted and that this disruption constitutes the strain from which nuclei of new grains can grow during recrystallization. Evidence for the existence of strain along glide planes was first detected by Taylor" in 1927 and substantiated by Collins and Mathewson&apos; in 1940. In their investigations, however, the deformed single crystalline specimens (aluminum) were cut mechanically along the glide planes followed by mechanical polishing. X-ray exposures (glancing angle) of only 8 min with filtered radiation were used. It was later shown&apos; that this type of surface preparation did not remove with all certainty the mechanically disturbed surface. It was felt that a re-investigation of this phenomenon using more refined techniques might reveal a more correct extent of the strain resulting from the deformation which might correlate the deviation of the common pole of the recrystallized grain with the acting slip plane of the matrix crystal. In accordance with these thoughts, a single crystal of a brass (70/30 nominal composition) M in. in diam x 5 in. long, tapered as in previous experiments,&apos; was extended and carefully documented with respect to elongation and shear. Disks about % in. thick paralle&apos;l to the primary slip planes were cut from the specimen by means of an etch cutter." These disks represented volumes of the specimen which had been extended 0, 5, 10, 15, and 20 pct. Copper Ka monochromatic radiation was obtained by reflecting 35,000 v copper radiation from the c-cleavage face of a pentaerythritol crystal. The monochromatic radiation was collimated and led on to the disk set at the proper 0 angle for reflection from the primary (111) planes. The monochromatic beam was aligned in a plane containing the active slip direction. Following a 10 hr exposure at the theoretical Bragg angle, the disk was reset at 0 + 1°, 0 — 1", 0 + 2", 0 — 2", etc., until no Bragg reflection was obtained. The disk was then rotated 90" about its polar axis, and the same X-ray procedure was used. The results are shown in Table I. It may be seen from the results in Table I that the plastic deformation (20 pct elongation) produces fragments of the glide plane which are rotated or tilted as much as 25 " from the normal position on a purely block slip model. In addition to the large variation in 0 angle in the slip direction, there is a variation in 0 as much as 20" in the direction at right angles to the direction of slip, i.e., <110>. In view of the results shown, it may now be argued that the strain distribution finds its origin in the incongruent nature of the slip process.&apos; The use of the two-stage rotation process seems valid in attempting to explain the relation between the orientation of recrystallized grains and the matrix from which they have grown. Acknowledgment This work was sponsored by the ONR under Contract Number N6 onr 234-21 ONR 031-383. The author would like to thank N. K. Chen for reading and correcting the manuscript. References &apos;R. Maddin, C. H. Mathewson, and W. R. Hibbard, Jr.: The Origin of Annealing Twins. Trans. AIME (1949) 185, p. 655; Journal of Metals (September 1949). &apos;J. A. Collins and C. H. Mathewson: Plastic Deformation and Recrystallization of Aluminum Single Crystals. Trans. AIME (1940) 137, p. 150. eN. K. Chen and C. H. Mathewson: Recrystallization of Aluminum Single Crystals After Plastic Extension. Unpublished. 4 C. H. Mathewson: Structural Premises of Strain Hardening and Recrystallization. Trans. A.S.M. (1944) 38. :&apos;C. H. Mathewson: Critical Shear Stress and Incongruent Shear in Plastic Deformation. Trans. Conn. Acad. of Arts and Science, (1951) 38, p. 213. "G. I. Taylor: Resistance to Shear in Metal Crystals, Cohesion and Related Problems. Faraday Soc. (1927) 121. &apos;R. Maddin and W. R. Hibbard, Jr.: Some Observations in the Structure of Alpha Brass After Cutting and Polishing. Trans. AIME (1949) 185, p. 700; Journal of Metals (October 1949). &apos;R. Maddin and W. R. Asher: Apparatus for Cutting Metals Strain-Free. Review of Scientific Instruments (1950) 21, p. 881.

Jan 1, 1953

By John E. Murphy, Ernest L. Ohle

Hematite-magnetite ore bodies at Iron Mountain, Missouri, have produced nearly 9 million tons of iron ore concentrates since 1844. The ore minerals occur principally as open-space filling in fractured and brecciated andesite porphyry with very minor replacement of the wall rocks. The enclosing rocks are Precambrian in age and consist of a series of dacite, rhyolite, and andesite flows aggregating about 2000 feet in thickness. All of the ore is in andesite and the mineralization is Precambrian in age. The shape of the ore bodies, the breccia character of the ore, and the gangue mineralogy are believed to be unique. One of the two main ore bodies is crudely dome-shaped with a tendency for development of concentric mineralized shells; the other is an elongated lense in plan but hook-shaped in cross section. Both have strong linear elements striking northeast, east-west, or northwest. Various modes of origin for the structures and for the tension breccias have been suggested, but none is completely satisfactory. Hematite is the main ore mineral; magnetite is subordinate. Important gangue minerals are andradite, quartz, calcite, actinolite, apatite, epidote, and chlorite. Although some evidence favors injection of an iron-rich melt, other evidence suggests ore formation by a high temperature, water-rich solution.

Jan 1, 1968

By W. H. Davitt

While it is true that taxes, especially income taxes, whether they be federal, state, or local, are not usually thought of as a "cost" of doing business, it is equally true that these tax costs do reduce the distributable profits just as much as the cost of power, supplies, or labor. Therefore, the consideration given to taxes is often as important as that given to other costs. Hopefully you will recognize that, within certain limits, taxes can be controlled to an economic advantage. The tax laws as now imposed are quite complex. Many of these laws and the regulations thereunder involve many factual determinations, technical considerations, and specialized valuations that can best be made by people trained in the specific area concerned. A substantial amount of a tax liability turns on the proper consideration given to issues involving facts and principles which are peculiarly engineering in nature. The importance of these "engineering" issues in tax administration has been significantly increased in recent years by our rapidly advancing technology, automation, stepped-up mineral and oil exploitation, new industries such as electronics and nuclear power, and the extension of percentage depletion to all minerals. These specialized requirements incorporated in the law are so technical that full consideration can not be given by people with a non-engineering background.

Jan 7, 1974

By J. M. Roberts, D. M. Barnett

The activation energy required to break a pinned dislocation line away from its condensed atmosphere of impurity atoms is calculated as a .function of applied stress, without neglecting line tension. Reasows are presented for not assuming the effect of line tension to be negligible when considering the problem of freeing a small segment of dislocation from an impurity atmosphere. The dislocation is considered to he pinned at each atomic size along its length and the pinning points are assumzed immobile. The development is a refinement of the origznal cottrell-bilby1 theory. The solution is compared to recent approximations developed by cottrell3 and Haasen5 in which line tension con- IN 1949 Cottrell and bilby1 considered the problem of determining the force required to pull a dislocation away from its condensed atmosphere of impurity atoms. They also examined the effect of thermal fluctuations on this force. The dislocation line was pictured as bowing out in a triangular loop under the action of an applied stress, and the activation energy necessary to free the dislocation from its atmosphere was calculated as a function of stress, line energy, and dislocation-solute atom interaction. siderations were neglected. A qualitative explanation of the yielding process in terms of the activation of Frank-Read sources is presented, but the lack of a realistic solution to the dynamic dislocation problem involved prevents an extension of the model at present. A self-consistent correlation between the present calculations and experimental data for delay time associated with yielding and the temperature dependence of the upper yield stress was made. Favorable agreement was noted. It is concluded that extension of the original Cottrell-~ilby&apos; theory which includes line tension effects can just as well describe the yielding process as other approximations3,5 which neglect line tension. Cottrell and Bilby found the form of the activation energy vs stress curves to be almost independent of the line energy and the interaction energy (i.e., these parameters only affected the activation energy U by a scale factor). A check of the theory was accomplished by comparison with the experimental data of McAdam and Mebs2 for the lower yield stress as a function of temperature. cottrell,3 in 1957, attempted to obtain a simple closed-form solution for the activation energy as a function of stress by linearizing the quartic equation relating displacement of the dislocation line and applied stress. It was argued that since the contribution to the line energy/atomic plane of a dislocation is made by the long-range stress field of the dislocation through a term of the type (Gb3/2p)ln A/ro, where

Jan 1, 1963

By C. E. Reistle, G. L. Nye

The East Texas field is in Smith, Rusk, Gregg, Upshur and Cherokee counties, Texas. The discovery well was completed Sept. 8, 1930, near the eastern limit of the field. Within less than one year the new field became the dominant factor in the world production of crude oil. On Aug. 16, 1931, eleven months after completion of the discovery well, there were 1644 wells in the field, and the average daily production was 584,475 bbl. Since that time the number of wells has increased to 8195 on Oct. 1, 1933, and the field has produced 385,979,691 bbl. of oil. The geology of the East Texas field has been discussed by Lahee,1 Levorsen,2 Minor and Hanna3 and others, and it will not be discussed in detail here. The field is a structure of the monocline type on the westward dipping homocline between the Sabine uplift and the East Texas geosyncline. Production is obtained from the Woodbine group, which has been truncated and then sealed by the Austin chalk, which rests unconformably upon it. The oil-saturated part of the sand lies bettween a sub-sea depth of 3050 ft. on the east side of the field, where the Woodbine sand stops and the Austin chalk rests directly upon older formations, and a sub-sea depth of 3320 ft., which was the average depth of the water table in the sand at the time the field was discovered. The field is about 40 miles long and has an average width of approximately 4 1/2 miles. The area within the proven limits of the field is close to 116,580 acres and the normal Woodbine water underlies nearly 62,000 acres on the western side of the field at the present time. The field is unusual in several respects: (1) the tremendous size of the reservoir system and the quantity of oil in place; (2) the large area of the oil and water contact, which makes water movement possible into the oil-bearing part of the structure; (3) the absence of free gas within the main producing sand of the field. Changes in the reservoir pressure during the production history of the field have been greatly affected by

Jan 1, 1934

By R. Maddin, W. R. Hibbard

A series of X ray experiments conducted by G. I. Taylor&apos; in 1927 and later substantiated in 1939 by J. A. Collins2 both on axially strained aluminum single crystals, revealed evidence that during single slip crystallite rotation occurs in such a manner that " all parts of the material rotated about the transverse direction in the plane of slip."l The actual method of preparing the specimens for X ray examination is not discussed in detail by Taylor except to say that "this specimen was cut parallel to the plane of slip, as calculated from measurements of marks in the surface of the specimen. It was ground and etched till the effect of the new cuts had disappeared. This was verified by applying the same treatment to an un-distorted specimen. The X ray reflectionsl in this case were perfect ones."&apos; Collins, on the other hand, cut his crystals in a mechanical shaper. These surfaces were polished on No. 1, No. 1/0, No. 2/0 and No. 3/0 papers and on a broadcloth lap using No. 600 alundum as a polishing medium. "Finally, the surface was deeply etched in Tucker&apos;s reagent. An unde-formed crystal was prepared in the manner described and X rayed to determine whether or not the machining and polishing operations had produced any strain or distortion in the crystal. The Laue spots all seem to be sharp, free from tails and streaks indicating no detectable strains had been introduced in the crystals." Taylor&apos;s X ray technique involved the use of "homogeneous X rays from an iron anti-cathode"; whereas Collins used Ka radiation of copper at 31kv and 20 milliamperes. Glancing angle X ray photograms were taken (1) with the axis of rotation of the spectrometer table in the plane of slip and at right angles to the slip direction, and (2) with the axis of the spectrometer table lying along the slip direction. However, eight minute exposures were used in each case and the angle setting of the spectrometer table was increased by one degree for each exposure. With the discovery of the action of three slip systems3 in the plastic deformation of single crystalline alpha brass where, formerly, only one had

Jan 1, 1950

By J. B. Mackintosh

The general method which has been followed since the time of Heinrich Rose, and perhaps before, for the determination of phosphorus in iron and steel, is to dissolve the sample either in nitric acid, aqua regia, or some other oxidizing agent, in order to convert the phosphorus into phosphoric acid. In 1832 Rose* recommends HNO3, or aqua regia, preferably the former. Wohler, in 1854,† directs that the iron should be oxidized by burning in a stream of oxygen for the determination of carbon, and the resulting oxide of iron containing all the phosphorus as phosphoric acid be treated as an ore. In the fourth English edition of Fresenius&apos; Quantitative Analysis,† pp. 666-667, we find directions to dissolve the iron in aqua regia or bromine; and, coming down to more recent times, we find F. A. Cairns § directing the employment of a boiling solution of potassium chlorate and hydrochloric acid for the oxidation and solution of the sample to be analyzed. It is unnecessary to multiply quotations from the literature of the subject, though they might be extended almost inclefinitely, since it would only be a repetition of the above mentioned series of methods in one form or another; and the references given have been selected to show how little essential variation there is in the type-methods of solution used. In fact it seems to be universally accepted as a necessary first step in the determination that some such method of solution should be followed. One chemist, however, struck out on a different line of thought, and to the Lest of my knowledge only one, M. V. Tantin, who, in

Jan 1, 1886

By Paul M. Tyler, Carle R. Hayward

DOES it pay to do really good work? Quite likely the practical millman will answer that it does not. The preparation of ores for market is primarily a business enterprise, and by and large the individual operator does not bother his head about squandering our national resources or making easier the job of the smelterman. Having accepted such ore as he may get fro111 the mine, his job is to make the best possible showing with his mill fro111 the standpoint of financial return. His success is measured in dollars and cents, and he has no rightful reason to expect more than scant acknowledgment of any other achievements from the stock- holders of his company who in the last analysis are his employers.

Jan 1, 1936

By Roussey Roussev

The use of chemical additives on grinding is of significant importance considering the high energy consumption of grinding processes. My research indicates that the dispersant approach explains the effects, in this particular case of wet grinding. Further, the dispersant approach combined with torque measurements give the possibility of clarifying the mechanisms involved when using grinding aids. I find the conclusions derived from the data obtained to be correct and useful for grinding. In general, I agree with the explanations. However, I would like to discuss several additional points that I consider to be important, and in the same time to mention some of my own results from investigations similar to those presented in the study under discussion. The "bed volume concept" and the change of slurry viscosity explain adequately the data plotted on [fig. 3], in conjunction with [Figs. 1 and 2]. However, the significant increase of the average torque in the case of 83% solid with XFS-4272 introduces the necessity of establishing the optimum of percent solid when dispersant is used. For example, the optimum percent of solid for different materials varies. One of the reasons is the material&apos;s mass density. On the other hand, it is necessary to determine the concentration of the chemical used. Because of this, it would be interesting to know how the cited concentration was selected.

Jan 1, 1983

By AIME AIME

EARLE EDWARD SCHUMACHER, the new Chairman of the Institute of Metal, Division. is well known to the metallurgical profession. His election a, Chairman is the culmination of fifteen years&apos; service to the Institute, beginning in 1930 when he was elected Member. Since that time he has served as member of the I.M.D. Data Sheet Committee. 1935-40; Papers and Publication Committee. 1936; Executive Committee. 1937-1910: Papers and Programs Committee, 1937-1938. (Vice-Chairman, 1939-40, Chairman. 1941-12): Annual Award Committee. 194142. (Vice-Chairman, 19431: Vice-Chairman, LM.D., 1943-44; Chairman Publication Committee, 1943-44; member Powder Metallurgy Committee), 1944. Pew other men have contributed so Much time anti effort in so many way- to the interests of the metals branch o4 the A.I.M.E.

Jan 1, 1945

By W. W. Stephens, W. J. Kroll, H. P. Holmes

THE only two methods for producing commercial quantities of malleable zirconium, up to now, have been using magnesium reduction of the anhydrous chloride under a neutral gas, and using purification of raw zirconium by the iodide dissociation method on a hot filament. The purity of the metal obtained by the latter process is about the same as that resulting from the chloride reduction, with the exception of the oxygen content, which may be about 0.05 pct lower in the iodide metal. Even traces of oxygen have a strong hardening effect on zirconium. Since, in the iodide process, the impurities, Si, Al, Fe, Ni, and Mg in the raw zirconium used, are carried over, it would appear uneconomical to use this method of refining solely to eliminate the traces of oxygen, unless very soft metal is desired. One important step to improve the iodide method, namely, dissociating pure iodide made from carbide and recycling the iodine, which would change this refining process into a method for extracting zirconium from the ore, has not yet been made. The Bureau of Mines, by using the chloride reduction, wanted to produce quantities of a reasonably pure and malleable metal at low cost for large-scale industrial use. This aim has been achieved, and a pilot plant permitting production of 600 lb of malleable zirconium per week will be described (fig. 1). Briefly, the Bureau of Mines process consists of reducing purified gaseous anhydrous zirconium chloride with fused magnesium under a noble-gas atmosphere. The reaction product, magnesium chloride, and any excess magnesium metal present are removed from the sponge zirconium in the next step by fusion and evaporation in a good vacuum at about 925°C. In this process, care is taken to keep air out of contact with the hot metal, which otherwise would contaminate the product with oxygen and nitrogen. Both these impurities embrittle zirconium even when present in an amount as low as 0.1 pct. A number of previous reports1-3 describe the method and the various improvements that finally led to a workable process. The major steps made were the production of large quantities of carbide, which is the raw material for producing the chloride, its chlorination with reasonable efficiencies, and the elimination of iron trichloride contained in the raw chloride, as well as that of the zirconium oxide which is always present in this product. The physical nature of the anhydrous chloride, which sublimes at 331°C at atmospheric pressure and melts at 420°C under a pressure of 25 atm, made it necessary to provide a special safety device on the purification and reduction vessels in the form of a lead-alloy seal, permitting escape of excess gases if pressure tended to build up. The main difficulties encountered in the reduction and in the following step, salt separation in a vacuum at elevated temperature, were caused by the material from which the reaction pot was constructed—iron. This metal reacts with zirconium at about 940°C with formation of a eutectic. The last step, salt separation by evaporation of the magnesium and magnesium chloride in a vacuum, is quite unconventional and has not been used before on such a scale. It is only due to the improved construction of high-vacuum pumps, especially oil-diffusion pumps, that such a method could be used. The various steps of the Bureau of Mines process, as described in the general outline above, may be summarized as follows: (1) production of the carbide, (2) chlorination of the carbide, (3) purification of the raw chloride, (4) reduction of the pure chloride with fused magnesium, (5) separation of excess magnesium and magnesium chloride in vacuum at elevated temperature, and (6) melting of the sponge obtained. Production of Carbide The arc furnace, described in a previous report,&apos; was improved both to reduce the graphite consumption caused by the burning of the bottom plates and to concentrate the heat in order to obtain better power efficiency. This was achieved by providing the bottom with graphite plates entirely embedded in refractory bricks, the contact with the current being made with three water-cooled copper plugs. Figs. 2 and 3 show the arrangement. The crucible, made

Jan 1, 1951