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THE following letter from the Rector of Louvain University, addressed to Mr. Adams and the other delegates of the Founder Societies, will be of interest to members of the Institute. It is my duty, in the name of the University of Louvain and in my own personal name, to thank you and the representatives of the Founder Societies of the "United Engineering Society" for the very kind letter of congratulations which you sent to me from Brussels on the 5th of July.

Jan 1, 1928

By R. T. DeHoff

A new approach to the measurement of the size distribution of particulate structures imbedded in opaque bodies is developed. The method is based upon the assumption of a general two-parameter distribution curve, and the estimation of these two parameters from three well-known counting measurements made upon metallogvaphic sections. The total number of particles in the system is also a product of the analysis. Application of the method with the assumption of the logarithmiconorma1 disfribution function is developed in detail. A complete description of the geometry of a particulate structure requires the determination of the size distribution of particles. The problem of estimating the size distribution of particles of a particular phase in a multiphase system, or the grain-size distribution in a homogeneous system, has been approached by many investigators.'-'0 All of the solutions proposed by these investigators share the following characteristics. a) A minimum of several hundred particle sections in the microstructure must be examined, and some characteristic dimension recorded, such as area,3'5 intercept length,6"9 or diameter.1'2'4'10 b) The resulting data must undergo a series of fairly complex calculations to generate the empirical histogram which describes the size distribution in three dimensions. c) In order to manipulate the result, the histogram must be fitted to some assumed mathematical formula, using the attendant statistical procedures. d) With two notable exceptions,8,10 the particles must be spherical. The measurements and calculations involved are in general very tedious and time-consuming, with the logical result that much effort has been expended in the development of equipment which will perform these tasks automatically and semiautomati-cally.9,11-15 considerable success has been achieved in this area, but the equipment is in general expensive, and usually places stringent requirements On the quality of microstructure which can be reliably analyzed. In laboratories which do not possess such equip- ment, the analysis of geometry is usually limited to measuring total properties of the microstructures, such as volume fraction and interfacial area, because the measurements required are much simpler to make. The determination of size distributions rarely is undertaken. The development which is presented in this paper permits the estimation of size distributions of three-dimensional structures from the same simple counting measurements which are required to determine the surface area and volume fraction of the particulate structure, and one other counting measurement. The basic approach that is used is to assume a general mathematical form for the distribution, which is described by two parameters (as the normal distribution is described by assigning values to the mean and the standard deviation), and then estimate these two parameters from the results of the counting measurements. The introduction of a third counting measurement also permits the evaluation of the number of particles per unit volume, Nv.

Jan 1, 1965

By R. P. Carreker, J. G. Leschen, J. H. Hollomon

The external appearance of a crystal which has undergone plastic flow suggests that adjacent blocks of the crystal have glided bodily past one another along the slip planes. However, the great discrepancy between the shear stresses calculated to effect such a movement and those actually observed has for many years stimulated searches for more satisfactory interpretations of the slip process. Appreciable success in these efforts has been realized by assuming the presence in the crystal of various sorts of imperfections and by considering the consequences of the presence of these flaws when stress is externally applied. The theory that has received the most attention recently—that of dislocations—postulates the occurrence of small, mobile imperfections or dislocations which move through the crystal along the slip direction, each dislocation being attended by a local shear displacement of one interatomic distance. Thus only that portion of the crystal through which the dislocation has passed may be said to have slipped. Since each dislocation produces a displacement of only one interatomic distance, an avalanche or train of many dislocations would be necessary to account for the observed displacements of several hundred or thousand interatomic distances. The salient point of the theory of dislocations is the concept that a slip band does not suddenly appear in its entirety. On the contrary, it grows progressively across the slip plane as the individual dislocations successively appear and advance in a train through the crystal. However, the concept of growth is not intrinsic only to the theory of dislocations, since atomistic mechanisms other than that postulated by the dislocation theory can quite probably also describe the growth of a slip band. For instance, a slip band might resemble a disc-like interface that appeared and then grew continuously from a small size, producing a displacement that increased with the size of the disc. Whatever the precise mechanism, the concept of growth is in itself consistent both with the observed low values of critical shear stress and with the experimental observation that slip bands frequently do not traverse the entire crystal. The likelihood that slip bands grow implies that they must first be nucleated and that the initiation of slip can therefore be analyzed in terms of the general concepts of nucleation. Indeed, this suggestion was advanced1 several years ago, but the matter does not appear to have been further pursued. Recent advances in the theory of nucleation 2,3,4 have encouraged such a treatment of the slip process. As will presently be demonstrated, this approach to the problem not only accounts successfully for the incubation periods that have been observed 5,6 to precede slip but also predicts certain transient effects in the deformation process. The existence of these transients apparently has not hitherto

Jan 1, 1949

By H. S. Rankin, E. C. Houston

OLIVINE is considered a valuable potential source of metallic magnesium in the chloride electrolytic process. Treatment of olivine with hydrochloric acid can be carried out under conditions that prevent the formation of gelatinous silicic acid, which would inhibit the reaction by forming a covering around the ore particles. It is our hypothesis that the formation of gelatinous silicic acid is avoided by the dehydrating action of the magnesium chloride, which takes up water to form a series of hydrates and leaves the silicic acid in granular condition. Leaching serves to separate the magnesium chloride from the silicic acid and unattacked ore, which can be treated with fresh acid in successive steps until extraction is essentially complete. The leach solution can be purified by the addition of caustic magnesia and the precipitated impurities removed by decantation or filtration. The resulting magnesium chloride contains: Fe, less than 0.001 per cent; Mn, 0.012 per cent; Ni, none. Chlorination[f] of olivine has two major defects: (1) a large part of the chlorine goes to form silicon and iron chlorides, (2) the anhydrous magnesium chloride is held by absorption in the finely divided silica. SUPPLY It is well known that olivine, a silicate of magnesium and iron, is present in large amounts in several localities in the United States. The largest deposits occur in the southeast and on the Pacific Coast.1 The southeastern deposits were surveyed by Lewis2 in 1896 and by Hunter3 in the period 1933-1940. It is estimated that high-grade olivine, conveniently located with regard to transportation and power, is present in excess of 230 million tons above local drainage level in western North Carolina and north Georgia. PREVIOUS TECHNICAL WORK In the past few years, olivine has attracted considerable attention in the refractory field. In the chemical processing industry, however, it has long been thought axiomatic that the cost of processing silicates is an economic barrier to their utilization, especially where more reactive minerals, such as carbonates, oxides or salts, are available. This attitude is not entirely justified in connection with olivine. Unlike most silicates, olivine is readily attacked by acids, chlorine and other reagents without resorting to fusion to break down the silicate structure. Olivine has been suggested as a raw material for making epsom salt by roasting with pyrites.4 Other processes include acid treatment5 and digestion with calcium chloride.6 Recently a small plant was built near Webster, N. C., for making epsom salt from olivine by treatment with sulphuric acid. This plant is now in commercial operation, producing approximately two tons per day. Olivine is also receiving attention from the fertilizer industry as an inexpensive source of soluble magnesium.

Jan 1, 1942

By R. Walker, R. J. Anslow

Today at Tampa we see the end results of a team effort: A vital link in an intermodal transportation system, the link that enables the unit-train concept to be employed with full effectiveness and the link that improves the economics of water transportation systems. Two new phosphate transfer complexes with a multi- million ton annual capacity are in operation in Tampa, Fla. Revolutionary in concept, these companion installations represent a total investment in the Tampa Bay area of $18.5 million.

Jan 1, 1970

By J. J. Arps, T. G. Roberts

Since the introduction of the relative permeability concept in the middle thirties1,2 various investigators have shown3,10,11,12,15 how the basic equations for the flow of oil and gas through porous media can he utilized to compute the recovery from depletion type or solution gas drive type reservoirs under certain conditions, when the necessary physical data pertaining to the reservoir rock and its reservoir fluids are known. In the study by Muskat and Taylor" in 1945, the effects of viscosity, gas solubility, shrinkage, and the permeability-saturation characteristics of the producing formation on the production histories and the recovery of gas drive reservoirs were analyzed. Each parameter was varied a limited number of times, while keeping the others constant. The work was not carried to the point where the data could be used directly to estimate the primary recovery in those cases where certain rock and fluid characteristics were known or could be assumed. Since the publication of this classic study, the work by Beal in 194616 and Standing in 1952'" has established general correlations of oil viscosity and shrinkage with gas solubility and oil gravity. In addition. a considerable number of relative permeability relationships for different types of reservoir rocks has been published2,5,13,17,19,20. Also, the burden of the numerical work required in the solutions of the differential equation has. during the last few years, been greatly reduced with the availability of modern electronic computing facilities. The purpose of this paper is therefore to present the results of a large number of such recovery computations covering the normal range of variation of the main parameters such as the type of rock, the API gravity of the oil, and the amount of gas in solution. As is to be expected, the ultimate recovery is found to increase with the oil gravity. except for the higher solution gas-oil ratios. Within the normal range of solubilities, the ultimate recovery generally appears to decrease with the amount of gas in solution for the higher oil gravities, and to show a slight increase for the lower oil gravities. Intermediate oil gravities seem to fall between the two trends. The type of reservoir rock, as identified by its relative permeability relationship, appears to have a very pronounced effect on the ultimate recovery. In general, sands and sandstones show higher recoveries than limestones and dolomites, although certain intergranular limestones seem to show a higher theoretical recovery than unconsolidated sand. The recovery from sands and sandstones generally decreases with increasing cementation and consolidation, while the recoveries from limestones and dolomites are highest for the intergranular type and lowest for the fracture type porosity.

Jan 1, 1956

By R. P. Carreker, J. G. Leschen, J. H. Hollomon

THE external appearance of a crystal which has undergone plastic flow suggests that adjacent blocks of the crystal have glided bodily past one another along the slip planes. However, the great discrepancy between the shear stresses calculated to effect such a movement and those actually observed has for many years stimulated searches for more satisfactory interpretations of the slip process. Appreciable success in these efforts has been realized by assuming the presence in the crystal of various sorts of imperfections and by considering the consequences of the presence of these flaws when stress is externally applied, The theory that has received the most attention recently-that of dislocations-postulates the occurrence of small, mobile imperfections or dislocations which move through the crystal along the slip direction, each dislocation being attended by a local shear displacement of one interatomic distance. Thus only that portion of the crystal through which the dislocation has passed may be said to have slipped, Since each dislocation produces a displacement of only one interatomic distance, an avalanche or train of many dislocations would be necessary to account for the observed displacements of several hundred or thousand interatomic distances. The salient point of the theory of dislocations is the concept that a slip band does not suddenly appear in its entirety. On the contrary, it grows progressively across the slip plane as the individual dislocations successively appear and advance in a train through the crystal. However, the concept of growth is not intrinsic only to the theory of dislocations, since atomistic mechanisms other than that postulated by the dislocation theory can quite probably also describe the growth of a slip band. For instance, a slip band might resemble a disc-like interface that appeared and then grew continuously from a small size, producing a displacement that increased with the size of the disc, Whatever the precise mechanism, the concept of growth is in itself consistent both with -the observed low values of critical shear stress and with the experimental observation that slip bands. frequently do not traverse the entire crystal. The likelihood that slip bands grow implies that they must first be nucleated and that the initiation of slip can therefore be analyzed in terms of the general concepts of nucleation. Indeed, this suggestion was advanced1 several years ago, but the matter does not appear to have been further pursued. Recent advances in the theory of nucleations2,3,4 have encouraged such a treatment of the slip process. As will presently be demonstrated, this approach to the problem not only accounts successfully for the incubation periods that have been observed5,6 to precede slip but also predicts certain transient effects in the deformation process, The existence of these transients apparently has not hitherto

Jan 1, 1948

By John Griffen

DURING the past year, purchases of coal-preparation equipment and the discussions and plant-scale tests conducted indicate that much attention is being given to better recoveries of coal by preparation plants and improved quality of the finer sizes to widen their market. In the anthracite regions the new equipment was predominantly for the cleaning of the steam sizes, much of it for treating No. 4 and No. 5 buckwheat. The units installed were largely coal-washing tables, Hydrotators, and Menzies cone separators.

Jan 1, 1944

By Frank Foote, E. R. Jette

In recent years the constitution of the high-silver aluminum-silver alloys has been extensively investigated. Hansenl has reviewed the literature to 1935. More recently, Obinata and Hagiya,2 Hofmann and Volk,3 Taziri4 and Tishchenko5 have confirmed the general features of the phase diagram in the region around 25 atomic per cent aluminum. In this paper we present the results of high-precision measurements of lattice constants of the silver-rich alpha solid solution in the homogeneous range and the neighboring two-phase regions. These results are used to establish the nature of the solid solution, the identity of directly measured densities with those calculated from lattice constants and the homogeneity limits of the alpha solid solution with respect to three different neighboring phases. A study of the earlier investigations indicated that the last two subjects in particular required new and accurate data. Experimental Procedure Preparation of the Alloys.—The alloys were made from high-purity silver and aluminum. The silver was "Proof Silver," 99.999 per cent pure, supplied by the U. S. Metals Refining Co. The aluminum was 99.97 per cent pure (contained Si, 0.009 per cent; Fe, 0.0016 per cent; Cu, 0.004 per cent) and was supplied by the Aluminum Company of America. The lattice constants of these two materials have been reported by Jette and Foote.6 Weighed amounts of the two metals were placed in alundum crucibles and melted in vacuo in a high-frequency induction furnace. The melts were allowed to cool in the crucible, the ingots thus obtained weighed about 10 grams. These ingots were then filed clean, hamered, again cleaned and given a homogenizing anneal in vacuo of from 6 to 15 days at temperatures ranging from 500" to 695°C. The ingots were air-cooled from the annealing temperature. Lattice-constant Measurements.—Carefully prepared filings for X-ray analysis were sealed into evacuated quartz or Pyrex tubes and annealed for various periods of time at suitable temperatures. The furnaces used were vertical, rapid-quenching furnaces, the samples being quenched by crushing the sample tube under water by means of a heavy plunger. The general X-ray technique has been previously described6 The cameras were of the symmetrical, back-reflection, focussing type. Ka, radiation from a cobait-nickel alloy target was used. The wave-length values were taken from the second edition of Siegbaum's book.7 A correction for the index of refraction was applied and the lattice constants were calculated by the method of Cohen.8, 6 The lattice constants were calculated to a common temperature of 25°C., using the value of the linear expansion coefficient of pure silver as 18.9 X 10-6. Presumably the expansion coefficient for

Jan 1, 1941

By Frank Foote, E. R. Jette

In recent years the constitution of the high-silver aluminum-silver alloys has been extensively investigated. Hansenl has reviewed the literature to 1935. More recently, Obinata and Hagiya,2 Hofmann and Volk,3 Taziri4 and Tishchenko5 have confirmed the general features of the phase diagram in the region around 25 atomic per cent aluminum. In this paper we present the results of high-precision measurements of lattice constants of the silver-rich alpha solid solution in the homogeneous range and the neighboring two-phase regions. These results are used to establish the nature of the solid solution, the identity of directly measured densities with those calculated from lattice constants and the homogeneity limits of the alpha solid solution with respect to three different neighboring phases. A study of the earlier investigations indicated that the last two subjects in particular required new and accurate data. Experimental Procedure Preparation of the Alloys.—The alloys were made from high-purity silver and aluminum. The silver was "Proof Silver," 99.999 per cent pure, supplied by the U. S. Metals Refining Co. The aluminum was 99.97 per cent pure (contained Si, 0.009 per cent; Fe, 0.0016 per cent; Cu, 0.004 per cent) and was supplied by the Aluminum Company of America. The lattice constants of these two materials have been reported by Jette and Foote.6 Weighed amounts of the two metals were placed in alundum crucibles and melted in vacuo in a high-frequency induction furnace. The melts were allowed to cool in the crucible, the ingots thus obtained weighed about 10 grams. These ingots were then filed clean, hamered, again cleaned and given a homogenizing anneal in vacuo of from 6 to 15 days at temperatures ranging from 500" to 695°C. The ingots were air-cooled from the annealing temperature. Lattice-constant Measurements.—Carefully prepared filings for X-ray analysis were sealed into evacuated quartz or Pyrex tubes and annealed for various periods of time at suitable temperatures. The furnaces used were vertical, rapid-quenching furnaces, the samples being quenched by crushing the sample tube under water by means of a heavy plunger. The general X-ray technique has been previously described6 The cameras were of the symmetrical, back-reflection, focussing type. Ka, radiation from a cobait-nickel alloy target was used. The wave-length values were taken from the second edition of Siegbaum's book.7 A correction for the index of refraction was applied and the lattice constants were calculated by the method of Cohen.8, 6 The lattice constants were calculated to a common temperature of 25°C., using the value of the linear expansion coefficient of pure silver as 18.9 X 10-6. Presumably the expansion coefficient for

Jan 1, 1941

By C. H. Burgess

ON June 5, 1947, Secretary of State George C. Marshall in a speech at Harvard University outlined a plan for the economic recovery of Europe. The plan contemplated that the United States should provide assistance which would enable the European nations better to help themselves and to help each other to reconstitute from their war-torn lands conditions which would make possible decent standards of living. The Foreign Assistance Act of 1948 was passed in April of that year, and established the Eco-

Jan 10, 1950

ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as follows : the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saunders Medal. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize, The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel. The scope of the term "iron and steel" shall be determined by the sub-committee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improvement of production and quality of material. 3. A sub-committee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval. 4, The awarding committee shall submit its report to the Iron and Steel Committee at its October meeting, and the award shall be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute, 5. The recipient of the award shall be designated "The Hunt Medallist," This prize is administered by the Iron and Steel Committee. Awards of the medal have been made as follows 1920-Robert Woolston Hunt. 1926-Charles Lewis Kinney, Jr. J. E. JOHNSON, JR., AWARD This award is made from the income of a fund of $3000 donated by Mrs. Margaret Hilles Johnson in memory of her husband, J. E. Johnson, Jr., who was a prominent engineer, author of two valuable volumes on iron blast-furnace construction and practice, vice-

Jan 1, 1928

By E. A. Gulbransen, J. W. Hickman

THE physical and chemical structure of the oxide films formed on metals and alloys is of interest in our understanding of their protective properties. According to Pilling and Bedworth,1 if the specific volume of the oxide is equal to or greater than that of the metal, a compact or continuous structure results; if the volume of the oxide is less, a cellular or porous structure forms. With the cellular type of coating the surface layer of oxide offers no impedance to oxidation; at a given temperature the rate of oxidation is quite constant. On the other hand, the compact type of coating acts as an effective barrier to oxygen and the rate of oxidation will follow a parabolic law. The recent work of Gulbransen2 and of Leontis and Rhines3 on the oxidation of magnesium indicates that it is not necessary for the volume of the oxide to be greater than that of the metal in order that the oxidation may follow a parabolic rate law. One exception to the rule of Pilling and Bedworth' is noted by Scheil;4 namely, tungsten. At 500° and 700°C long-time oxidations indicate a linear rate law with time. However, Dunn's5 oxidation measurements from 700° to 1000°C indicate that a parabolic rate law is followed. The oxide is mainly yellow W03 with a thin layer of the blue oxide. Preliminary results on the oxidation of tungsten6 in the temperature range 400° to 500°C indicate that the oxidation does proceed according to a parabolic rate law. Irrespective of the actual rate law that tungsten may obey, it is of interest to compare the results obtained on the oxidation of tungsten in the thin film region with those found when the metal is scaling. A time-temperature study of the oxides formed on both molybdenum and tungsten may indicate whether there exist any peculiarities in the oxide structures of the thin film region compared with those of the scaling region of oxidation. In a recent paper the authors' presented an investigation of the structures of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper. The results of these studies are presented in graphical form as existence diagrams of the oxides on a time-temperature scale. The existence diagrams of the oxides occurring on some of the metals are simple and show few chemical transitions, but there are many cases in which the physical state of the oxide surface changes as a function of time and temperature, as evidenced by the appearance or disappearance of orientation effects and sharpness of patterns. In general an increase in temperature results in an increase in

Jan 1, 1947

By Irving Lipkowitz

While the light metals are recognized generally as a distinct group in technical literature, economic classifications and data usually still treat them as part of the nonferrous group of metals. However, the economic characteristics of the light metals also differ markedly from those of other nonferrous metals. The distinctiveness of the light metals, as, a group and individually, becomes evident when their growth, since World War II is compared with that of other metals, as in Table 14.3.1. The growth of light-metals production has been much sharper than that of other metals. A weighted average for the light metals shows an increase of 112% during the 1958 to 1968 period. This compares with a 62% increase in the "All Primary Metals" component of the Federal Reserve Board Index of Industrial Production. The contrast was even sharper during the next six years (1968-1974), with light metals production up another 50% as against a 21 % increase in the FRB Primary Metals production index. The most important reason, however, for considering light metals separately is the trend and pace of technological change and not their distinctive statistics. Technology both creates and demands increasingly sophisticated materials. As technology advances and as all the world makes more extensive use of advanced technology, the importance of the light metals is likely to accelerate rapidly. There may be a profound clue to the future in the fact that light metals were predominant among the materials used in the construction of the Apollo 11 spacecraft. In determining what materials to use for the spacecraft and its equipment, the National Aeronautics and Space Administration (NASA) has explained that it did not look to "some of the more exotic metals" and relied instead on "generally proven materials." Accordingly, it apparently used a wide variety of metals, including precious metals, rare earths, special steels, copper, and light metals. What seems particularly significant is that, in seeking performance, NASA relied as heavily as it did on the light metals. Materials breakdown estimates show that aluminum accounted for over 75% of the materials used, titanium for another 5%, and magnesium was also used. Thus, light metals accounted for over 80%' of the materials used for the Apollo 11 spacecraft. The light metals are also unique in their availability. They rank high in abundance among the elements in the earth's crust. Aluminum is the third most abundant element, after oxygen and silicon, with magnesium ranking eighth, and titanium ninth. Among the structural metals, aluminum is the most abundant in the earth's crust, iron is second, magnesium third, and titanium fourth. This potential availability of light metals provides strong incentives for continuing improvements in process technology, because of two major national problems: (1) there is

Jan 1, 1976

The great Bingham Canyon mine and mill complex of Magna, Arthur, and Bonneville had their beginning in a 300 ton per day operation which was commenced by Daniel C. Jackling and his associates in 1904 as the Utah Copper Company. This small plant was quickly expanded to 500 tons per day and eventually Kennecott, the Utah Copper successor, was processing about 45,000 tons per day of ore in each of its mills, Magna and Arthur. Finally, in 1966, the Bonneville crushing and grinding plant was added to produce a slurry of ground ore for flotation concentration at the expanded Magna and Arthur mills. Bonneville is one of the few railroad dump primary gyratory crushing plants constructed in recent years; another which is described in this Monograph is Cuajone in Peru, started in 1976. Two others are the Climax Henderson unit and the Phelps Dodge Tyrone crusher, which has been fed by trucks since it commenced operation. The Bonneville, Henderson, and Cuajone crushers are all located considerable distances from their mines, hence the use of rail haulage. Shovels in the Bingham pit are 8 to 15 yd capacity; and ore is sent to the Bonneville crusher in 100 ton rail cars, where they are dumped, two at a time, by a hydraulically driven rotary dumper. Ahead of the 54 in. by 74 in. Allis-Chalmers gyratory are two grizzlies, each 27 ft 9 in. (8.46 m) long with bar spacings of 4 ½ in. (114 mm) at the feed end and 6 in. (152 mm) at the discharge end. Grizzlies are sloped at 38. Oversize rocks are re- moved from the crusher pocket by an overhead crane, and the crusher produces a nominal 6 in. (152 mm) product. Rail cars are dumped in the direction away from the crusher, and water sprays at the dumper level and in the rock boxes are used for dust suppression. There are two 72 in. by 19 ft (1.83 m by 5. 8 m) apron feeders under the 500 st cr'ushed ore pocket and two more under the grizzly undersize pocket. Feeder speeds are variable up to 72 fpm. Grizzly undersize is dropped to the feeder pocket by three shelves forming a rock ladder attached to the pocket walls. Each pair of apron feeders, one for crushed ore and one for grizzly undersize, discharge to a 72 in. (1. 83 m) picking belt for tramp removal; this belt feeds one of two 54 in. (1.37 m) feeder conveyors which in turn discharge to a 60 in. (1. 52 m) takeaway belt operating at 175-300 fpm (53.3 - 97.4 mpm). Both picking belts are equipped with metal detectors and tramp iron magnets, and a separate 30 in. (760 mm) conveyor is used to remove tramp material.

Jan 1, 1978

By J. S. Aronofsky, R. Jenkins

A simple means of predicting the flowing well pressure history in a natural gas reservoir has been developed. The differential equation for unsteady radial flow of gases through porous media was solved by numerical methods using electronic punch card machines. The results obtained from these calculations are presented in a generalized form which is believed to be most convenient for engineering use. These results are compared with those presented in a paper by Bruce, et al4. An effective radius of drainage has been defined which permits the equation of steady state gas flow to be used easily to predict well pressures in gas reservoir depletion. An equivalent effective radius of drainage is defined for liquid flow systems and a comparison is made of the gas solution to the liquid solutions. INTRODUCTION This paper presents a numerical method for describing the transient flow of gases radially through a porous medium from which the production rate is specified. The results obtained from these calculations are presented in a generalized form which is believed to be the most convenient for engineering use. The principal application of these calculations should be to flow in natural gas reservoirs, in the interpretation of pressure drawdown tests, in the estimation of reserves, and in calculation of injection pressures required in gas injection and cycling operations. The evaluation of natural gas wells is based upon back-pressure tests in which measurements of production rate and flowing well pressure are made for periods of one, two, or more days. The flow is assumed to have stabilized at this time, and the observed values of pressure and production rate are used with standardized formulae to determine the well's allowable production rate. Furthermore, the results obtained from such a test of short time duration are extrapolated in such a manner to allow a prediction of what the well pressure will be at some future time for a specified (but possibly untested) flow rate. The manner of conducting such back-pressure tests suggests several questions as follows: 1. 'What is the definition of stabilized flow and what factors determine the length of time required for the flow to become stabilized? 2. How may the recorded values of pressure and rate be utilized? 3. As the well is produced and the reservoir pressure falls, how will the flowing well pressure change? Can this flowing well pressure be predicted from the back-pressure test? 4. Are the results obtainable from the test influenced by a particular procedure used in obtaining the results? 5. Is it possible to estimate the gross reservoir permeability from back-pressure data? It is not within the scope of this paper to provide solutions Or even to discuss adequately all the above questions. However. in considering such matters, the

Jan 1, 1955

By W. D. Robertson, D. A. Koss, A. J. Goldman

THE significance of the hcp (E) structure, which appears when Fe-Cr-Ni alloys (stainless steels) are transformed martensitically, has been the subject of considerable study and speculation.'-7 It has been proposed that the hcp structure is an intermediate phase in the transformation: fcc (austenite) — hcp (E) -bcc (0, martensite). However, recent studies by transmission electron microscopy6,7 have indicated that the hcp structure may be a consequence of the large shear strain (10 deg) associated with the fcc to bcc transformation. That is, the transformation to a bcc structure is accompanied by extensive dissociation of dislocations in the parent austenite, which has a low stacking-fault energy.'-'' X-ray diffraction analysis of the transformed alloy reveals a pattern of lines corresponding to an hcp structure, together with the parent austenite and the bcc product. The fact that the hcp structure is observed only in association with the bcc product in these alloys1'4'6'7 lends support to the conclusion that the hcp structure is a secondary product of the transformation. But, the evidence is circumstantial and more definite resolution of the two possibilities mains to be obtained. If the hcp structure is an intermediate product of the transformation, as in 1) above, then two distinct Ms temperatures should be observed, Ms and To evaluate this possibility, three different techniques that are particularly sensitive to the structural changes accompanying such transformations have been used in an attempt to detect two transformation temperatures in an Fe-15.1 Cr-11.7 Ni alloy: 1) high-sensitivity differential thermal analysis, 2) the temperature dependence of resonant frequency (elastic moduli), and 3) internal friction of cylindrical specimens vibrating in either longitudinal or torsional modes. To obtain the necessary sensitivity, a differential thermal analysis technique was developed for the purpose, Fig. 1. The differential temperature between a nickel standard and the specimen was amplified to produce a sensitivity of 0.02OC (0.7 v) in temperature difference. The specimen and the standard were surrounded by a copper block and the entire assembly was immersed in a solution of methyl and ethyl alcohol, freezing point, - 140OC, which provided the necessary thermal stability to reduce temperature fluctuations to negligible proportions. A cooling rate of about 1.5OC per min was obtained by bubbling liquid nitrogen through the liquid bath. In order to calibrate the experiment with respect to the evolution of heat in the transformation from fcc to hcp structures, differential cooling curves were obtained for an Fe-19.8 Mn alloy, which transforms martensitically to E.'"-' a Ms(e) temperature of 145°C was clearly defined by a temperature

Jan 1, 1964

By W. T. Bishop

FOR many years pine oil has been used extensively as a frother for the flotation of minerals, particularly sulphides, yet the published information available to the average user on its composition, chemical and physical properties, has been rather meager. It is the purpose of this paper to discuss these points and their relationship to the frothing properties of pine oil used in flotation processes. Pine oil, as the name implies, is a liquid obtained from the processing of wood of the longleaf and other southern pines. It is a complex mixture of naturally occurring terpene derivatives, primarily alcohols, and a smaller amount of terpenes, which has found many uses in various industries. Its use as a frother in flotation processes was the first large-scale application in industry and today the mining industry still consumes large quantities of pine oil but the textile and disinfectant industries consume comparable volumes. Much is used in soap manufacture and laundry operations. The surface-active properties of pine oil are in a large degree responsible for this versatility. HISTORY The name "Naval Stores" goes back to the days when pine tar and pitch were used to caulk leaky ships and coat their ropes and rigging. Today this term is still used to include not only the oleoresinous products of the pine tree-rosin and turpentine-but other products such as pine oil, pine tar, and the many terpene and resinous compounds obtained by extracting the pine wood or tapping the tree. That part of the industry known as "wood naval stores" dates from about the beginning of this century and today produces a large part of the country's rosin and turpentine by processing pine wood. In addition, all of our natural pine oil is, supplied by the wood naval stores industry, as tapping of the live tree gives only rosin and turpentine. This latter phase is known as the "gum naval stores" industry. The first successful commercial operation of the steam and solvent process of the wood naval stores in industry was carried out by Yaryan at Cadillac, Mich., in 1909.1 This operation did not prove profitable, so Yaryan went south to utilize the longleaf pine, and built a plant at Gulfport, Miss.2 Soon after, another plant was built at Brunswick, Ga., which is still in operation, and in 1914 was reported to have processed about 500 tons of wood per day.1 In 1921 Hercules Powder Co. acquired the Yaryan interests, at which time the production of pine oil was only 3 to 5 million pounds per year and flotation was the largest customer. As time went on, technological advances were made, other companies entered the field, and the production of pine oil increased many fold. The growth of the industry was especially marked during the past 10 years, and in

Jan 1, 1946

By Walter Showak

The published phase diagrams for the copper-zirconium system1,2 indicate that the solid solubility of zirconium in copper is not accurately known. Studies made on relatively impure alloys by Pogodin, Shumova, and Kugucheva3 yielded a maximum solubility value of 1 wt pct Zr at the eutectic temperature. Allibone and sykes5 reported that an as-cast 0.2 wt pct Zr alloy is single phase at room temperature. Limited results obtained by Raub and Enge14 indicated that zirconium solubility in copper is less than 0.13 wt pct Zr at 940°C. Tn 1960, on the basis of a microstructural examination of several copper-rich Cu-Zr alloys, saarivirta6 placed the maximum solubility of zirconium in copper at 0.15 wt pct at the eutectic temperature, 980°C. The present note describes results obtained during a re-investigation of the Cu-Zr system for the purpose of accurately establishing the solidus and solvus curves and the eutectic temperature in copper-rich alloys. High-purity copper (99.99 pet) and zirconium (99.64 pet) consolidated reactor grade sponge were used to prepare several alloys, containing up to 2 wt pct Zr, by induction melting in graphite crucibles in vacuum and chill casting into a split steel mold. The melting procedure consisted of first melting the copper charge and then adding the bulk zirconium wrapped in pure copper foil. Chemical analyses were made of both the cold-rolled alloy ingots after homogenization at 925°C for 450 hr in evacuated quartz capsules and of small specimens which had been used in the phase diagram studies. 'The carbon content of each alloy was also determined and was found to be less than 0.001 wt pct in every case. Metallographic and electrical resistivity measurements were used as the primary methods for this investigation, although some thermal analysis studies were also performed. Heat treatments of all the alloys were carried out with the specimens wrapped in molybdenum or alloy foil (of the same composition as the specimen) and sealed in quartz tubes either in vacuum or under a purified helium atmosphere. Following high-temperature anneals for long periods of time, slight depletion of zirconium from the specimen surface was observed. Therefore, careful preparation of samples for microscopic examination and chemical analysis of the samples themselves was necessary to check the composition of samples used in determining phase boundaries. Points on the solvus curve were determined on quenched specimens by both isothermal reaction after solution heat treatment at 950°C for 8 hr and by isothermal annealing of alloy specimens at successively higher temperatures for times ranging from 24 to 500 hr. Liquation studies for positioning of the solidus and eutectic temperatures were performed by holding a pre-

Jan 1, 1962

By J. B. Cohen, M. B. Beaver, R. J. Black

RECENT investigations have shown that face-centered cubic metals may deform by twinning. Blewitt, et al' found that at 4.2"K the mode of def~rmation of single crystals of copper changed at large strains and markings formed on (111) planes. Later they- emonstrated by X-ray diffraction and metallography that the markings were twins and showed that favorably oriented single crystals of copper deformed by twinning at 78°K. They also observed twinning in silver and gold deformed at 4.2 and 78°K. Wagner3 obtained evidence for twinning from the peak shape of diffraction lines of silver cold-worked at 78°K, but twins small enough to cause such effects are not likely to be detected metal-lographically. In the work reported here lamellar structures were observed in deformed silver-gold alloys. They appeared to be mechanical twins, but metallography could not establish this conclusively. Their tendency to form depended on strain rate, temperature and composition. Specimens of silver-gold alloys (0 to 83 wt pct Au) were deformed plastically. One set was worked by hammering under liquid nitrogen, at room temperature and at intermediate temperatures. Another set was compressed slowly in liquid nitrogen to the same reductions as those produced by hammering. Tensile specimens (0.015 x 0.120 x 1.5 in.) of various compositions and approximately equal grain size (0.011 to 0.016 cm) were tested at -195°C and at room temperature. In microsections of all specimens deformed by hammering at —195°C thin lamellae appeared, Fig. 1. They were aligned in definite directions in each grain. In some grains they had two orientations. Where lamellae intersected, a displacement was apparent. Near the center of the left margin of Fig. 1 shear has taken place beyond the fully developed intersecting lamella. Many lamellae resembled Neumann bands in alpha iron. They were parallel to one side of triangular etch pits in the matrix (as in Figs. 1 and 2). The individual lamellae were narrow and had little substructure. This suggested that they did not result from concentrated local slip. The shape of etch pits within the lamellae differed from that of pits in the matrix, as can be seen in Fig. 2; this indicated a difference in orientation. Specimens slowly deformed at —195°C contained regions in which the lamellae were clustered. In these specimens some lamellae were bent and presumably had formed before the termination of the deformation. Structures of greater width than the lamellae were also seen.4 More lamellar structures formed on impact than during slow compression to a given reduction. This was true of all compositions. The structures became less abundant with increasing temperature of deformation. None was observed after extension to fracture at room temperature, but they could be pro-

Jan 1, 1959