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By C. W. Washburne

Recently, Messrs, Mills and Wells1 published a thorough chemical study of the waters associated with oil in parts of the Pennsylvania, Ohio, and West Virginia region. Many of their conclusions are of general application and the writer wishes to discuss some of these. Messrs. Mills and Wells show that the composition of the deep brines oi the Appalachian fields is such as would be produced by the evaporation of sea water and the precipitation of sodium chloride, combined with reactions with hydrocarbons and other substances. The brines are altered, also, by considerable mixing with meteoric water. They give good reasons for believing that the concentration of the brines was produced by evaporation in the rock pores induced by migrating gas, much of which probably escaped to the surface of the ground. This hypothesis was considered by the writer in a former paperJ2 in which main stress was laid on a second hypothesis, that the excess of chlorine in the deep brines may have been due to the entrance of solutions rich in magnesium and calcium chloride which ascended from a deep, possibly intratellurie, source. Messrs. Mills and Wells present good arguments for the first hypothesis. Underground evaporation by ascending gases probably will be accepted as the best available explanation of the concentration and composition of deep well waters. They have not considered the possibility that salt waters in deep sands may be concentrated by the diffusion of water vapor through gas into shale. The writer has given reasons3 for believing that capillary forces concentrate gas and oil in the larger openings of rock, such as the pores of sandstones embedded in shale. The gas underground must be nearly saturated with water vapor at all times, because it always is in contact with the interstitial water of enclosing shales and of the sandstone. Experimental studies of soil moisture have shown that approxi-

Jan 1, 1921

By H. B. Pulsifer

THE unprecedented high price of zinc ore prevailing through the early months of 1915 caused great activity in the Joplin district of Missouri. The Media mill is conspicuous as one of the first of the new "big mills" of the district. The mill was built over a mine previously worked but abandoned in 1912 because of the leanness of the ore and the large quantity of water encountered. The ore prices prevailing-$100 a ton in June, 1915, as against $50 in 1912-favored the new undertaking. The mill was designed for good recovery so that it might operate in times of depression. In design and equipment, the mill is exclusively local in conception and construction. Former Exploitation The tract of land is a part of the large Guinn holdings; 70 acres are comprised in this particular lot, which is situated just a mile north of the center of Webb City on the Alba line of the Southwest Missouri Electric Railway. The ore lies 242 ft. below the' surface at the top of the knoll which is surrounded by the well-known properties: Black Cat, Ground Floor, Florence, Hurry-Up, Electrical and Mercantile. Since the abandonment, in 1913, of the Yellow Dog. a bit farther to the north, the Black Cat, Ground Floor and Florence workings had been flooded. However, as there was no cut through from this side into the area it was proposed to exploit, it was thought that moderate pumping facilities would take care of the water.

Jan 5, 1917

By Richard W. Smith

Kyanite, long known to occur in Georgia, did not excite coimmercial interest until about 1930. Investigation1 revealed two main types of deposits: (1) separate kyanite crystals embedded in mica schist; and (2) crystal aggregates of kyanite associated with quartz in small and very irregular veins. The second kind at first sight appeared to be the best source of supply. Large boulders or dornicks of kyanite with more or less quartz were found on the surface at many places throughout the Piedmont and Highland sections of the state, but prospecting failed to disclose a sizable vein. These dornicks seem to be a surface accumulation from small veins or lens-shaped masses not more than one or two feet thick, and with a horizontal extent of not more than a few feet. 'rile larger surface accumulation of kyanite dornicks, where not too badly stained by iron oxide, may prove to be marketable, but it is extremely doubtful whether a vein large enough to mine will ever be found. In 1932 deposits of the kyanite-mica schist were known to occur in two places northwest of Clarkesville, in Habersharn County. In 1934, at the request of and in cooperation with the Georgia Geological Survey, the United States Geological Survey made a thorough investigation2 of the deposits and found that the two known areas of kyanite-mica schist in Habershain County were but a part of an unsymmetrical, U-shaped belt (Fig. 1) with a western limb extending into Rabun County and somewhat longer than the eastern limb. The total length of the belt is about 30 miles. The width of outcrop ranges from 100 ft. to 1/4 mile or more. Deposits of kyanite-mica schist of very doubtful commercial importance were found in several other counties. Only the deposits of this kyanitc-mica schist belt in Habersham and Rabun counties will bc discussed in this paper. Geology The kyanite-mica schist of Habersham and Rabun counties occurs near the northern cdge of the Piedmont Upland in metamorphic rocks of pre-Cambrian age3. These rocks probably were deposited as sedimentary

Jan 1, 1938

By Richard W. Smith

Kyanite, long known to occur in Georgia, did not excite coimmercial interest until about 1930. Investigation1 revealed two main types of deposits: (1) separate kyanite crystals embedded in mica schist; and (2) crystal aggregates of kyanite associated with quartz in small and very irregular veins. The second kind at first sight appeared to be the best source of supply. Large boulders or dornicks of kyanite with more or less quartz were found on the surface at many places throughout the Piedmont and Highland sections of the state, but prospecting failed to disclose a sizable vein. These dornicks seem to be a surface accumulation from small veins or lens-shaped masses not more than one or two feet thick, and with a horizontal extent of not more than a few feet. 'rile larger surface accumulation of kyanite dornicks, where not too badly stained by iron oxide, may prove to be marketable, but it is extremely doubtful whether a vein large enough to mine will ever be found. In 1932 deposits of the kyanite-mica schist were known to occur in two places northwest of Clarkesville, in Habersharn County. In 1934, at the request of and in cooperation with the Georgia Geological Survey, the United States Geological Survey made a thorough investigation2 of the deposits and found that the two known areas of kyanite-mica schist in Habershain County were but a part of an unsymmetrical, U-shaped belt (Fig. 1) with a western limb extending into Rabun County and somewhat longer than the eastern limb. The total length of the belt is about 30 miles. The width of outcrop ranges from 100 ft. to 1/4 mile or more. Deposits of kyanite-mica schist of very doubtful commercial importance were found in several other counties. Only the deposits of this kyanitc-mica schist belt in Habersham and Rabun counties will bc discussed in this paper. Geology The kyanite-mica schist of Habersham and Rabun counties occurs near the northern cdge of the Piedmont Upland in metamorphic rocks of pre-Cambrian age3. These rocks probably were deposited as sedimentary

Jan 1, 1938

By Danforth R. Hale, R. E. Blair

Minerals for electronic and optical uses divide easily into two sections: (1) quartz and (2) minerals other than quartz. Quartz Quartz, having a great usefulness discovered by the radio communication enthusiasts about 1918, has become a subject of amazingly expanded interest in the US over the past decade as a man-made mineral and a multimillion dollar crystal-growing business. An economic summary of the commercial growing of quartz crystals has a place in a handbook directed to the mineral engineering industry when it is remembered that quartz crystals have long been an important commercial mineral, and that the raw material for "cultured quartz"-that is to say, quartz crystals grown through the ingenuity of man-is still natural quartz. Nearly all the natural crystals come from Brazil. The larger pieces which meet rigorous standards of quality are used for electronic and, to a lesser extent, optical components. Smaller pieces and fragments are used for vitreous silica. The need for high quality material in quantity led to US government-sponsored research programs in the 1940s that have resulted in the factory growing of beautiful crystals of prescribed shape, size, and quality. The development of the cultured quartz crystal is typical of man's success in adapting the product of the mine to increasingly sophisticated uses. A remarkable achievement perhaps, but foreshadowed by experiments in 1908 by Giorgio Spezia (1908), an Italian geologist studying the relative effects of temperature and alkaline environment on the solubility of quartz. Modern radio equipment is most often controlled as to frequency by the presence in the circuit of a separately added "crystal"-the 1918 discovery responsible for the existence and growth of the quartz industry. The "crystal" is quartz, but this component is a carefully oriented and prepared slice from a crystal, but not a crystal as recognized by a rock hound or seen in a museum. How quartz operates to control frequencies is not a proper subject for a handbook on industrial minerals, and references should be consulted (Cady, 1964; Mason, 1964). Quartz belongs to that class of materials called dielectrics: those that do not conduct an electric current but permit electric fields to exist and act across them. Quartz shows the "piezoelectric effect," which means that when a quartz plate is mechanically deformed against its natural stiffness, one of its surfaces becomes negatively charged, the other, positively charged. When the plate is released from the stress quickly, the charges disappear as the plate regains its original shape, but because of mechanical momentum the plate deforms in the opposite direction (to a lesser amount) and the surfaces correspondingly become charged in the opposite direction. By coating the two surfaces thinly with metal and attaching flexible wires, these charges may be brought into an electronic circuit. If the surfaces are suddenly electrically charged by movement of current through the wires, the "converse piezoelectric effect" occurs -the plate deforms. Carry the thought further and it is realized that an alternating current flowing through the wires responds to the mechanical oscillation of the plate and is keyed to this oscillation. By controlling the thickness of the plate its mechanical vibration frequency can be varied through a wide range. One type of quartz plate, called the AT-cut, having a precisely defined orientation with respect to the crystallographic axes of the crystal, vibrates on a microscopic scale much as a book would deform when placed flat on a table and the top cover moved parallel back and forth with the hand. There are at least 17 other orientations which have been studied, some of

Jan 1, 1983

By W.G. Harbert, C. Upthegrove

DURing the past year considerable work dealing with physical properties of cartridge brass was done at the University of Michigan in cooperation with the Ordnance Department of the U. S. Army. This paper gives some of the data bearing on the effect of the anneal, previous to the final reduction-or rolling, on the physical properties, particularly the hardness. Various phases of the subject of physical properties of cartridge brass have been presented by different investigators. Mathewson and Phillips1 refer to the work of Grard, in 1909, as the first systematic presentation of the relation between temperature and time of anneal, changing of physical properties and microstructure, and the previous reduction by cold rolling. They discuss the relation between time and temperature of annealand the previous reduction by cold rolling; also the relation between physical properties and grain size of annealed brass. The degree of deformation previous to the annealing was found to determine the temperature at which recrystallization and corresponding changes in physical Properties would take place. relation between grain size and Brinell hardness, found the hardness for low-temperature annealing to be dependent on the previous degree of reduction, while for anneals above a certain temperature the hardness after the anneal was independent of the degree of reduction. Actual differences in hardness, due to the degree of reduction, disappear only on annealing at 600" C. or above; though the differences for metal subjected to different degrees of reduction and annealed at temperatures between 350" and 600" C. were found to be relatively small. In their determination of the relationship of grain size to Brinell hardness, Bassett

Jan 1, 1923

By W. G. Harbert, C. Upthegrove

DURing the past year considerable work dealing with physical properties of cartridge brass was done at the University of Michigan in cooperation with the Ordnance Department of the U. S. Army. This paper gives some of the data bearing on the effect of the anneal, previous to the final reduction-or rolling, on the physical properties, particularly the hardness. Various phases of the subject of physical properties of cartridge brass have been presented by different investigators. Mathewson and Phillips1 refer to the work of Grard, in 1909, as the first systematic presentation of the relation between temperature and time of anneal, changing of physical properties and microstructure, and the previous reduction by cold rolling. They discuss the relation between time and temperature of annealand the previous reduction by cold rolling; also the relation between physical properties and grain size of annealed brass. The degree of deformation previous to the annealing was found to determine the temperature at which recrystallization and corresponding changes in physical Properties would take place. relation between grain size and Brinell hardness, found the hardness for low-temperature annealing to be dependent on the previous degree of reduction, while for anneals above a certain temperature the hardness after the anneal was independent of the degree of reduction. Actual differences in hardness, due to the degree of reduction, disappear only on annealing at 600" C. or above; though the differences for metal subjected to different degrees of reduction and annealed at temperatures between 350" and 600" C. were found to be relatively small. In their determination of the relationship of grain size to Brinell hardness, Bassett

Jan 1, 1923

By Enrique Touceda

For a number of years prior to the world war, the firm of Geo. H. Thacher & Co., of Albany, N. Y., was engaged in the manufacture of marine and other gray-iron castings. At the outbreak of the war the firm decided to specialize in the manufacture of propeller wheels. It attacked the problem, therefore, from a foundry point of view, seeking to produce a casting that would be so accurate that no subsequent machining would be required on the blades, also from the point of view of the ship builder. There were two general methods of manufacture, the shortcomings of which have been freely acknowledged. In the sweep method, the nowel, or bottom half-mold, for each blade is swept up by a spindle beam and pitch race, while the top half-mold for each blade is built up individually. In the pattern method one individual blade, with the hub or hub portion, is mounted on a spindle and the individual blade mold formed, the pattern is then rotated on the spindle to the position for the next blade, etc. In rare cases wheels were made from a solid pattern. Owing to the cost of the pattern, its failure in many instances to be correctly made, and (when made of wood) its early and sure distortion the disadvantage of this pratctice is obvious, while metal patterns in most instances were prohibitive in cost. In these methods both green-sand and loam molding was practiced. The casting produced by either method can be considered only as a blank from which the propeller must be machined. The back surface of each blade must be chipped to the templet and through this procedure chipped to such accuracy as will be required for a static balance. Inasmuch as the work done by the machine tool is confined to the driving face of the blades, not only is perfection most difficult, but corrosion will be greater because of the removal of the dense skin of the casting and the local strains set up by the pneumatic tool in chipping. To produce a finished 9-ft. propeller for a Navy destroyer required from 8 to 21 days of foundry work and about the same length of time for the machining. Through the use of the Thacher process, only as many hours are required, besides it is possible to produce a finished casting in perfect conformity with any particular propeller-wheel design.

Jan 1, 1922

By Enrique Touceda

For a number of years prior to the world war, the firm of Geo. H. Thacher & Co., of Albany, N. Y., was engaged in the manufacture of marine and other gray-iron castings. At the outbreak of the war the firm decided to specialize in the manufacture of propeller wheels. It attacked the problem, therefore, from a foundry point of view, seeking to produce a casting that would be so accurate that no subsequent machining would be required on the blades, also from the point of view of the ship builder. There were two general methods of manufacture, the shortcomings of which have been freely acknowledged. In the sweep method, the nowel, or bottom half-mold, for each blade is swept up by a spindle beam and pitch race, while the top half-mold for each blade is built up individually. In the pattern method one individual blade, with the hub or hub portion, is mounted on a spindle and the individual blade mold formed, the pattern is then rotated on the spindle to the position for the next blade, etc. In rare cases wheels were made from a solid pattern. Owing to the cost of the pattern, its failure in many instances to be correctly made, and (when made of wood) its early and sure distortion the disadvantage of this pratctice is obvious, while metal patterns in most instances were prohibitive in cost. In these methods both green-sand and loam molding was practiced. The casting produced by either method can be considered only as a blank from which the propeller must be machined. The back surface of each blade must be chipped to the templet and through this procedure chipped to such accuracy as will be required for a static balance. Inasmuch as the work done by the machine tool is confined to the driving face of the blades, not only is perfection most difficult, but corrosion will be greater because of the removal of the dense skin of the casting and the local strains set up by the pneumatic tool in chipping. To produce a finished 9-ft. propeller for a Navy destroyer required from 8 to 21 days of foundry work and about the same length of time for the machining. Through the use of the Thacher process, only as many hours are required, besides it is possible to produce a finished casting in perfect conformity with any particular propeller-wheel design.

Jan 1, 1922

By C. R. Fast, George C. Howard

Laboratory and field testing of various squeeze cementing techniques and materials revealed that many improvements could be made in squeeze cementing operations. The use of a slow-pumping squeeze cementing procedure permitted the control of the quantity of cement displaced into a formation and aided in obtaining a high final squeeze pressure. Field testing indicated the desirability of obtaining high final squeeze pressures, the need for improved formation breakdown fluids, and the necessity of controlling the pressure differential during testing after a squeeze job. INTRODUCTION During the past few years, squeeze cementing operations have been investigated, both from the theoretical as well as the practical point of view, in an effort to arrive at some solution to the many and varied problems that arise with this type of operation. A review of well files indicated that in many instances, wells were being squeeze cemented four and five times before a satisfactory pressure buildup was obtained. There seemed to be considerable variation in opinion as to the proper method of squeeze cementing, as well as disagreement as to the proper breakdown agent, the quantity of cement that should be used, type retainer and length of WOC* time that was necessary. Consequently, it was deemed advisable to approach this problem theoretically, field testing each idea developed in hopes of eventually arriving at a squeeze cementing procedure that would give reasonable assurance of a successful job after one squeeze cementing operation. This investigation was. therefore, divided into two broad headings: (1) Preliminary studies, which include both theoretical and laboratory studies, and (2) Field investigations to determine the proper squeeze cementing methods. PRELIMINARY STUDIES Overburden Pressure Studies Squeeze cementing problems are so intimately related to the earth's overburden pressure that solutions to them are very difficult, if not impossible, without an understanding of the nature and magnitude of the overburden pressures encountered at the depths of producing wells. It was thus felt that the first approach to research on squeeze cementing should be made through a study of these pressures. Since there has been rather loose usage of a number of the terms related to overburden preasure by different writers, the terms to be subsequently used are defined here. Theoretical overburden pressure is the calculated pressure at any given depth exerted by the theoretical weight of overlying formations as calculated from the average rock density. Fluid displacement pressure is that pressure at which fluid can be injected into a formation after it has been broken down. It may be more or less than the theoretical overburden pressure. Formation breakdown pressure is that pressure at which a formation parts or breaks and is usually thought of as fluid displacement pressure plus rock strength. Breakdown agent is that fluid with which the formation is fractured. The first step in the study of the earth's overburden pressures involved a review of pertinent technical literature. The general opinion expressed was that the overburden pressure gradient of the earth's formations is roughly 1.0 psi per foot of depth, and that application of sufficient pressure to stratified formations. will cause them to part at or parallel to the bedding planes. The second step in the study of overburden pressures involved a study of available well data in an effort to obtain some definite information as to the actual values experienced in the field for the above mentioned terms. Data from 115 cement squeeze jobs in the Gulf Coast area and 46 cement squeeze jobs and acid jobs in the West Texas-New Mexico area were closely analyzed. The analysis of these data showed that the average formation breakdown

Jan 1, 1950

By O. Z. Klopsch, G. L. Craig

The fabrication characteristics and properties of phosphorized arsenical Lake copper have been compared with phosphorized prime Lake and phosphorized electrolytic seamless copper tubing, in a series of mill-scale tests employing commercial drawing schedules. Phosphorized arsenical coppers containing as much as 0.20 per cent arsenic were drawn with various reductions into 7/8and 3/8in. seamless tubing along with billets of the two types of arsenic-free copper. The effect of arsenic was determined by the average power required to draw given compositions and by the final properties of the respective materials in the annealed condition and after various degrees of cold reduction. Power consumption data show that no more power is required to draw arsenical coppers of this type than the arsenic-free copper. The result? of tensile tests indicate that arsenic increases the strength of cold-drawn tubing somewhat, but has no measurable effect on the properties of annealed tubing; the ductility of the tubing as evidenced by the elongation and other prescribed tests is unaffectetl by 0.20 per cent arsenic.

Jan 1, 1933

By R. E. Gilmore

This paper is a revision of a former paper published in mimeograph form by both the Canadian and American coal classification committees, and is now presented for the purpose of acquainting those interested with the present status of coal classification in Canada. The classification employed for "Customs purposes" is detailed, and the classification schemes from which the customs classification was derived are reviewed and discussed. The activities of the Canadian coal classification committee, namely, the Associate Committee of Coal Classification and Analysis of the National Research Council, is also reviewed. Reserves, Production and Uses of Canadian Coals The total coal resources of North America are estimated to be 69 per cent. of those of the world, and of this portion, the distribution is 52 per cent. for the United States and 17 per cent. for Canada. Accordingly, Canadian coal resources amount to approximately one-third of those of the United States, and one-sixth of those of the world. As for the geographical distribution, the bulk of the known coal deposits are in the extreme eastern and western portions of the country. Employing the usual, more or less loosely defined, designations for the different classes and subclasses of coal, the distribution of the Canadian coal resources, according to provinces, is as follows: Maritime Provinces: Nova Scotia and New Brunswick Bituminous and semibitu- minous coals. Ontario (northern part).............................Lignite. Saskatchewan, (and Manitoba)....................... Lignite. Alberta and British Columbia........................ Lignites, subbituminous, all kinds of bituminous, semibituminous and semianthracite coals. Of the total reserves, roughly 92.5 per cent. is credited to the noncok-ing lower rank subbituninous and lignite groups, the bulk of which are

Jan 1, 1930

By D. R. McCord

Data of a known statistical quality has been successfully used in a system of conventional fluid mechanics equations essentially free of empirical "conformance factors to prediet early detailed field 03 in a reservoir where gravity drainage is important and oil and rock properties vary con. siderably. The system is useful where comparative recovery predictions for one or more cases of natural depletion and gas cap pressure maintenance are needed and the reservoir is not too heterogeneous. INTRODUCTION Many authors, have examined various facet* of the gravity drainage-gas cap pressure maintenance problem over the last several years. Two of them. Burtchaell and Elkins, have published practical studies. In the case described in the present paper the best development and operating plan for one of the important reservoirs of the Bolivar Coastal Field in Western Venezuela was urgently needed. It was requested that sound comparative economics be presented along with an engineering evaluation of no additional drilling, maximum drilling. several cases of gas pressure maintenance, of water flooding and combination cases. A rapid analysis of the effect on recovery of the range of crude and rock properties indicated that none of the published methods using average properties would yield adequate comparative predictions. This paper covers the predictive system developed to deal with natural depletion and gas cap pressure maintenance. The large amount of data available for this field permitted statistically reliable correlations to be made of most rock and oil properties, and the evident smooth areal variations of these properties encouraged the construction of a lineal mathematical model of material balance and fluid flow equations, which could be manipulated by a modified iterative procedure. The manipulation is much more adaptable to computing machines than manually operated calculators and subsequent studies have been prepared for the IBM Card Program Calculator. A matrix as opposed to linear model has been tentatively worked out by other members of our group to deal with more heterogeneous reservoirs. It is more adaptable to computers such as IBM-701 or the Remington-Rand Univac. In 1950, when the system reported below was developed, no rapid computing machines were available to the author. Their existence and promise encouraged an initial approach by hand. Some details of oil and rock Property correlation are included because there are a surprisingly large number of medium-sized reservoirs in the world that show systematic property variations which are significant for a rigorous analycon. All large reservoirs (over half a billion barrels recovery) with which the author is familiar contain at minimum a significant temperature variation. Using the rock and oil property correlations, past pressure and production, the gas-oil ratio history of the reservoir was computed and found to be in close agreement with field measurements. The future performance under cases of natural depletion, gas injection of 100 MMcf/day, and of 130 MMcf/day, was then computed; a 70 MMcf/day case was also carried far enough to provide data for comparative economics. The 130 MMcf/day case proved to be the most attractive. A 50,000 horsepower gas turbine driven centrifugal compressor plant to take this quantity of adjacent field gas from 30 to 1,950 psia and inject it into the reservoir is under construction. The total cost of the project will exceed 20 million dollars.

Jan 1, 1953

By H. I. Aaronson

THE TTT-curve for the beginning of transformation in hypoeutectoid steels containing appreciable amounts of relatively strong carbide-forming alloying elements often exhibits a "bay" at intermediate temperatures. In many of these steels, proeutectoid ferrite is the initial product of the decomposition of austenite not only at temperatures above the bay but also in an appreciable temperature range below the region of the bay. Hultgren has postulated that ferrite formed above the bay, termed "orthoferrite", contains the equilibrium concentration of alloying element at temperatures above the eutectoid range, and the extrapolated metastable equilibrium concentration at lower temperatures. The ferrite formed below the bay, on the other hand, termed "paraferrite", was assumed to inherit completely the bulk alloy content of the austenite without regard for the compositional requirements of equilibrium. As shown schematically in Fig. 1, the two types of ferrite were taken to have different Ae3 temperatures and different C-curves on a TTT-diagram. Their different kinetic behaviors were thus considered responsible for the bay in the TTT-curve for the proeutectoid ferrite reaction in this type of alloy steel.

Jan 1, 1962

By J. E. Hove

The high temperature physical properties of graphite are reviewed and interpreted in the light of present day knowledge of the mechanisms affecting these properties. The thermal and mechanical behaviors only are discussed and, whenever possible, comparisons are made with other refractory materials. Possible further studies are indicated, including some carbide work. AS long as the term high temperature implied only temperatures up to about 1000°C, the materials problems which arose could usually be handled by fairly conventional metal alloy types, such as the Co-Cr-Ni superalloys, for which there exists a great deal of technology. Perhaps this temperature can still be considered an upper limit for normal applications, but it is certainly true that the number of abnormal applications is increasing rapidly. The advent, in recent years, of ram-jet and rocket missiles and of high power nuclear reactor heat sources has raised a host of questions concerning the basic problem of what material to use in the temperature range up to 2000°C and higher. While there are, of course, many metals, in the second and third transition series, which melt at considerably higher temperatures than this, these metals are, at present, pretty well excluded from practical use by other considerations, such as re-crystallization, chemical activity, or excessive plastic deformation. The behavior of metals, from the standpoint of dislocation theory, is just beginning to be understood and thus there is some hope for the future development of very high temperature metals, but the immediate problems would most logically appear to have solutions involving the nonmetals, such as the refractory ceramics and graphite. For this reason, there is presently a great deal of engineering and experimental research being performed on the latter materials, much of this research being exploratory in the sense of gathering new property data. The situation, so far as graphite is concerned, is somewhat more fortunate than with the other refractory solids in the sense that a great deal is already known about its basic properties. This stems both from the fact that the carbon-carbon bond has been of interest to chemists for a long time (and graphite can be considered as a very large aromatic molecule, if desired) and the fact that its properties, both as a function of temperature and of radiation damage, are of critical importance to nuclear reactor designers. It is still true, of course, that such fundamental questions as why graphite remains solid to such a high temperature and why it has such a high thermal conductivity cannot entirely be answered at the present time. It is, nonetheless, meaningful and instructive to consider such problems in the light of existing knowledge. This is what the present paper will attempt to do. Before going on, it may be appropriate to classify graphite and justify its discussion before readers primarily interested in metals. Graphite is comparatively unique among materials in that there is always a property or group of properties which precludes calling it either a metal, a semiconductor, or a ceramic. It has the high electrical and thermal conductivities of a metal, but the artificial, poly-crystalline types show a negative thermal coefficient of electrical resistivity, generally characteristic of semiconductors. On the other hand, semiconductors, by definition, show an ever increasing resistivity as the temperature is lowered, whereas graphite approaches a finite, and, indeed, a rather low resistivity in the region of 10°K and, furthermore, a good single crystal of graphite has a positive temperature coefficient, as for a metal.' On still another hand, its porosity and brittleness at lower temperatures would put graphite in the ceramic class although, unlike most ceramics, it is readily machinable and has a high resistance to thermal shock. All things considered, it is probably more nearly appropriate to call graphite a metal than anything else. Although certainly outstanding in some ways, graphite has its peculiarities and, especially if the reader is unfamiliar with the data, it is probably valuable to review some representative property variations at high temperature. This review is meant to be mainly illustrative and no attempt has been made to be exhaustive. Review of High Temperature Properties At ordinary pressures, graphite does not melt, but sublimes directly into the gaseous phase at about 3700°C. Although the phase equilibrium diagram is still in some doubt, graphite will melt, at a slightly higher temperature, at pressures in excess of about 100 atm. The chief difficulty of using graphite in an oxidizing atmosphere is that the reaction rate becomes quite high at fairly low temperatures. If a threshold oxidation temperature2 is defined as the temperature at which graphite loses 1 pet of its weight in 24 hr, the value in air is 450°, the value in steam is 700°, and the value in carbon dioxide is 900°C. Efforts are presently being made to raise this threshold temperature either by impregnation with a retardant of some type (sodium tung-state and phosphoric acid, for example) or by a suitable metal or oxide coating. It is probably fair to say that, to date, these attempts have not shown any outstanding success in all respects. Most commercial graphites are fabricated by impregnating a carbon flour (say of coke or lampblack particles) with some type of hydrocarbon

Jan 1, 1959

By Frederick Laist

IN the course of the past 75 years the treatment of copper ores has undergone the most profound changes. To a lesser degree, this is true of all the nonferrous metals, but the rapid increase in the demand for copper due to the phenomenal growth of the electrical industry, and the discovery of vast new ore deposits in Michigan, Montana and Arizona, provided an exceptional incentive for improvements in smelting practice and for large-scale operations. Because these must perforce be carried on in regions where labor was scarce and wages high, the need for mechanization and larger smelting units soon became apparent. At a later date the porphyry coppers were discovered, with ores so low in grade that enormous tonnages had to be treated daily if they were to be made to pay at all. In some instances these ores were associated with, or overlain by, oxidized ores, which could not be concentrated mechanically and, of course, could not be smelted directly. This led to the development of the copper-leaching process. While the principles of the various smelting and leaching processes are for the most part of European origin, and have long been known, modern practice is essentially American and was evolved on this side of the Atlantic. The ores of copper may be divided into three general classes; viz, native copper, sulphide and oxidized ores. By far the greater number of commercially important ore deposits come under the classification of sulphides. Commercial deposits of native copper are limited to the Lake Superior

Jan 1, 1947

By Alden B. Greninger

In a recent study1 of the deformation of metastable beta copper-zinc and beta copper-tin crystals, it was established that the parallel markings that appear on the surface of these crystals after slight deformation represent lattice transformations. Stereographic analysis showed that in beta copper-tin, the poles of these markings deviated one or two degrees from poles of the form {133}. In beta copper-zinc the plane delineated by the markings corresponded to no one crystallographic plane of the matrix lattice; the marking poles deviated from 5° to 11° from poles of the form (110), and were displaced only a few degrees from (110) zones. Inasmuch as the new transition lattices produced as the result of the deformation are different for each alloy, it was thought at first that the habits of the markings might be the result of a cooperation between matrix lattice and transformed lattice. (Both matrix lattices arc body-centered cubic.) Such a cooperative effect is thought to obtain in the formation of Widmanstätten figures, for it is well known that the matrix lattice alone does not determine the habit assumed by a segregate phase. On the other hand, it is not inconceivable that the dissimilarity in marking habit might be due to differences in deformation characteristics of beta brass and beta bronze. Barrett and co-workers2 have shown that slip-line habits in pure iron are markedly different from those in high-silicon ferrite; and although it has been repeatedly demonstrated that plates of a segregate phase do not necessarily form on the slip planes of the matrix lattice, deformation characteristics may be more intimately allied with plate formation when a transformation is made to occur as a result of plastic deformation. However, there is the fact that the orientation of markings in metastable beta copper-zinc is the same whether the markings be produced by quenching, deformation, or liquid-air cooling; likewise, quenching and deformation markings in metastable beta copper-tin are oriented in the same way with respect to the beta matrix. During the course of the investigation referred to above, samples of 52:48 (stable beta) copper-zinc were deformed and examined micro-

Jan 1, 1938

By Alden B. Greninger

In a recent study1 of the deformation of metastable beta copper-zinc and beta copper-tin crystals, it was established that the parallel markings that appear on the surface of these crystals after slight deformation represent lattice transformations. Stereographic analysis showed that in beta copper-tin, the poles of these markings deviated one or two degrees from poles of the form {133}. In beta copper-zinc the plane delineated by the markings corresponded to no one crystallographic plane of the matrix lattice; the marking poles deviated from 5° to 11° from poles of the form (110), and were displaced only a few degrees from (110) zones. Inasmuch as the new transition lattices produced as the result of the deformation are different for each alloy, it was thought at first that the habits of the markings might be the result of a cooperation between matrix lattice and transformed lattice. (Both matrix lattices arc body-centered cubic.) Such a cooperative effect is thought to obtain in the formation of Widmanstätten figures, for it is well known that the matrix lattice alone does not determine the habit assumed by a segregate phase. On the other hand, it is not inconceivable that the dissimilarity in marking habit might be due to differences in deformation characteristics of beta brass and beta bronze. Barrett and co-workers2 have shown that slip-line habits in pure iron are markedly different from those in high-silicon ferrite; and although it has been repeatedly demonstrated that plates of a segregate phase do not necessarily form on the slip planes of the matrix lattice, deformation characteristics may be more intimately allied with plate formation when a transformation is made to occur as a result of plastic deformation. However, there is the fact that the orientation of markings in metastable beta copper-zinc is the same whether the markings be produced by quenching, deformation, or liquid-air cooling; likewise, quenching and deformation markings in metastable beta copper-tin are oriented in the same way with respect to the beta matrix. During the course of the investigation referred to above, samples of 52:48 (stable beta) copper-zinc were deformed and examined micro-

Jan 1, 1938

By P. H. Brace, N. A. Ziegler

The study of the relations between gases and metals is one of pcren-nial interest to all who are connected with the production of high-grade metallurgical products. The data reported here are the outcome of work of which the object is to determine the effects of dissolved gases upon the properties of metals and to gain a more detailed knowledge of the reactions between gases and molten metals, particularly iron, under definitely controlled conditions. We have attempted to reduce our margin of error by dealing with relatively large quantities of metal, from 4 to 13 Ih. (2 to 6 kg.), and keeping the ratio of refractories to metal as small as practicable. The ingots produced are large enough to provide adequate material for making determinations of magnetic and other physical properties. In choosing the bell-jar type of furnace we were influenced by the results of considerable experimentation along the same general line which indicated that, for the scale on which we were to work, it was important to have the furnace structure independent of the vacuum enclosure. The use of a bell-jar surrounding the entire furnace accomplishes this and also gives great freedom of observation during operation and ready accessibility for the replacements which are necessary after each run. Our choice of analytical method was made in the light of the results secured by H. M. Ryder, who used a method similar in principle for the analysis of very small quantities of gas extracted from strips of metal heated electrically in high vacuum. We have presented some selected preliminary experirnental data as being illustrative of the quantity and nature of the gases which occur in iron of different origins, but do not urgc any hypothesis at this time. The Furnace Our furnace may be described as "a high-frequency induction furnacc of the bell-jar type." It is similar in a general way to that described by Cain and Peterson1 though we have introduced certain refinements of

By Wallace E. Johnson, Leslie R. Hill

As part of a continuing study of intense energy effects on the earth, such as explosive cratering for Plowshare, large scale hydro- dynamic computer codes which numerically integrate the two-dimensional mass, momenta, and energy conservation equations have been adapted for use on geological materials. Experimentally determined nonlinear dynamic equations of state and constitutive equations governing material strength are incorporated into a two-material Eulerian code, DORF. With the use of this code, impact studies have been made of projectiles with arbitrary shapes in the r,z cylindrical plane normally incident on semi-infinite half-space targets. The impact of projectiles on rocks has been studied empirically and experimentally; however, this paper employs a theoretical approach. Particular examples selected involve the impact of aluminum and iron projectiles on oil shale at velocities of 0.5 and 1.0 cm/µsec. These studies offer a quick and economic means to edit quantities unavailable in an experiment and to independently study the effect of varying parameters such as material shape, density, and strength, and impact velocity. Results reveal early time agreement with experimental high-speed photography as seen in the bowl-shaped crater and spray. Initial impact pressures at the projectile-target contact are in close accord with the one-dimensional Rankine-Hugoniot relations for the impact of dissimilar materials. These equations require local continuity of pressure and particle velocity across the interface and were found to hold locally, quite independent of projectile shape. Essentially all projectile energy is transferred quickly to the oil shale target (tens of microseconds). Over 75% of the original kinetic energy

Jan 1, 1971