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By E. S. Bartlett, D. N. Williams

QUANTITATIVE values for the oxidation rate of unalloyed molybdenum in air at temperatures above the melting point (1460°F) of the characteristic oxide are contained in the literature as a result of previous investigations. Lustman' reported values corresponding to 0.36 in. penetration per day (IPD) at 1500 and 1600°F in still air, noting essentially no variation in rate with temperature. Jones, Spretnak, and Speiser' reported values corresponding to 0.14 and 0.13 IPD at 1500 and 1800°F, respectively, in still air, attributing the decreased oxidation rate at higher temperatures to a lesser accumulation of the corrosive molten oxide on the surface at the higher temperature as a result of increased volatilization rate. Harwood3 ecently summarized work in the field, presenting generalized data corresponding to 0.48 to 0.96 IPD at 1800°F and 0.55 to 0.83 IPD at 1700°F in slowly flowing air. In a recent program at Battelle, it became desirable to know more about the characteristic oxidation behavior of molybdenum under varying conditions of temperature and atmosphere. Using oxidation-test apparatus designed for dynamic, continuous recording of weight change during testing,' values for the oxidation rate of molybdenum were obtained at temperatures from 1400 to 2150°F. In addition the effect of air flow on the oxidation rate was studied briefly at temperatures of 1600, 1800, and 2000°F. Exhaust of the contaminated atmosphere from the oxidation chamber was effected by an impeller pump attached to a 3/16-in.-diam opening in the oxidation chamber. The volumetric exhaust rate (cubic feet per hour) was normally maintained slightly in excess of the input rate to avoid condensation of MOO,,' on the sample suspension rod. The entering atmosphere was preheated prior to admission to the oxidation chamber by a 1 1/2-in.-diam cup packed with shredded asbestos. The experimental data are presented in Table I. Comparing conditions 2 and 3 (taking into account the temperature difference) and conditions 8 and 9. shows that in the absence of forced exhaust an atmosphere of moving air results in greater oxidation rate than a stagnant atmosphere. The use of forced exhaust, as shown by comparing conditions 3 and 4 and conditions 14 and 15: resulted in an even greater increase in oxidation rate. By virtue of the size of the atmosphere input and exhaust openings, it was calculated that the exhaust velocity was about 60 times that of the input velocity for essentially equal volumetric flow rates. Because of the proximity (about 3/4 in.) of the exhaust port to the specimen, it is logical to assume that cleansing of the atmosphere immediately surrounding the specimen was accomplished much more efficiently by the exhaust flow than by the input flow at a constant-volumetric flow rate. Also, it can be seen by comparing conditions 4 through 7 and conditions 11 through 13 that increasing the rate of atmosphere flow (by increasing input velocity with a proportional increase in exhaust velocity) above some optimum value has little, if any, further effect on the oxidation rate. These results suggest that there is a maximum oxidation rate for molydenum at a given temperature which is obtained when conditions are maintained such that the partial pressure of MOO3 in the atmosphere surrounding the specimen is at a low value. By controlling the partial pressure of MOO, surrounding the sample, it is possible to control the rate of volatilization of MOO:, from the surface. This, in turn, affects the rate of oxidation, since the thickness of the MOO3 layer determines the amount of oxygen which will be able to reach the reaction surface.' When the liquid oxide layer is less than some critical thickness, i.e., when the volatilization rate is high, enough oxygen is transported to the active surface to permit oxidation to proceed at the maximum rate allowed by the kinetics of the oxidation reaction. However, if the volatilization of MOO,, is suppressed, the thickness of the layer of MOO3 on the surface increases, and the diffusion of oxygen through the oxide layer becomes the rate-controlling step in the oxidation process. The lack of agreement between the present results and those of previous investigators is presumed to be due to differences in removal of the oxidation product (Moo,) from the immediate vicinity of the sample. By comparing conditions 1, 5, 10, 12 and 14, it is seen that when forced exhaust was used the oxidation rate of molybdenum increased with increasing temperature. A rapid increase was observed between 1400 and 1600°F, attributable to the effects

Jan 1, 1959

By Roy Lindgren

SINCE the year 1643, when the first blast furnace in America for treating iron ore was built at Saugus, Mass., out of mica schist quarried in the neighboring district, the procurement of a suitable refractory for furnace lining has been a problem of concern to the operators of furnaces. The stacks built of mica schist continued to smelt iron ore until about 1836, when, according to F. H. Norton, the first firebrick were produced1, at Queens Run, Pa. Other writers speak of brick having been molded and burned in Massachusetts about the year 1834. In 1841, Andrew Russell began to produce medium refractory plastic clay brick near East Liverpool, Ohio, that were used for lining blast furnaces1. The well-known Kentucky clay-producing district was not opened up until the year 1871, but since then it has produced a large percentage of the linings for iron blast furnaces. While some strides have been made by the refractories industry during the 100 years that have passed since the first firebrick were produced, it has been only during the last two decades that any real progress has been made towards bettering the product, even though the method of production had improved. Perhaps the fault lies with the user of the brick rather than with the producer, for not sooner demanding a supe-rior product. During the past 15 years the tonnage produced per lining has increased from 500,000 gross tons to 1,000,000 gross tons, and now some furnaces are producing 1,600,000 gross tons and better on a single lining. It is true that enlarged capacity of furnaces and improved practice have accounted for some of this increase in tonnage, nevertheless better quality in firebrick must be given credit for its share. However, we are not yet ready to say that we have reached a maximum life of furnace lining. We believe that a better product can be produced and that the refractories industries of America will, through their extensive research depart-

Jan 1, 1937

By Persifor Frazer

From the easternmost point reached by the Ural excursion of the VIIth International Geological Congress (the city of Tschéliabinsk, a little more than 30' of longitude east of St.

Jan 1, 1899

By N. H. van Lingen

A laboratory stud], has been made to determine what factors affect the penetration rate of roller bits, diamond bits and drag bits in rock drilling with clay /water muds. The rather simple relations that exist when pressures in and around the borehole are equal become more conzplicated when under down-hole conditions the penetration rate is hampered by the existence of a pressure differential between the mud at the hole bottom and the pore liquid at cutting depth. Expressions that have been derived for both the penetration rate and the magnitude of the pressure differential in permeable rock together fully account for operating, rock, mud and bit variables. In impermeable rock a similar pressure differential is caused by the bit action itself. In all cases, the pressure difierential and the reduction in penetration rate increase with the effectiveness of the plastering at the bottom of the hole by mud particles. Where bits are employed whose action is largely that of crushing, however, the plastering may become even more effective owing to the addition of rock particles rubbed into the pores of the rock. With roller bits, a plastically hehaving layer may be formed, which causes a further reduction in penetration. In the case of bits whose action is chiefly scraping, moreover, penetration may be arrested by the bit's becoming balled-up. The various adverse effects are reduced by thorough scavenging of the hole bottom. This paper shows how with jet bits the efficiency of such scavenging may he improved by suitable choice of the position of the nozzles. INTRODUCTION The reduction in a bit's penetration rate with increasing depth of hole has been the subject of many investigations. Various investigators ',' have independently reached the conclusion that this reduction occurs not so much because the rock-breaking process becomes more difficult as it does because the lifting of the rock fragments is impaired by a fluid pressure differential holding the fragments down. When such a pressure differential can be avoided, as in air drilling and to a smaller extent in water drilling, penetration rates remain high. Although the range of applicability of these techniques is being extended, most oil wells still have to be drilled with mud. In this paper we present the results of laboratory experiments carried out to determine what factors govern the hold down effect encountered in mud drilling. In the course of this investigation, the well known importance of bottom scavenging came more and more into prominence. Not only may it reduce the magnitude of the hold-down forces, but also it appeared to be a means of preventing the accumulation of a plastic mass of cuttings and mud on the hole bottom and bit which may cause penetration to cease almost completely. So that the effects of fluid pressures may be more readily understood, the factors that govern penetration rate in the absence of these pressures will first be discussed. The effect of down-hole pressures will then be assessed for the case of permeable rock where fluid pressures are well defined, and it will be demonstrated how rock strengthening due to confining can be accounted for. Subsequently, fluid pressures in less-permeable rock will be examined; we will show that in impermeable rock it is the bit action that governs fluid-pressure distribution and hold-down. In the case of poor scavenging and/or high bit load. cutting cake manifests itself. The effect, like various others. appears to depend on the type of bit used. From the very beginning, therefore, we shall base our discussion on the three main types of bits used in rotary oil-well drilling— roller bits, diamond bits and drag bits. Since space is limited, it will be impossible to make more than a passing reference to many aspects of the problem. Moreover. certain relations that are not of primary irnportance to our argument will unavoidably have to be stated in a somewhat dogmatic fashion, and the experimental data on which these are based necessarily must be omitted. EQUIPMENT The drilling experiments were performed on three machines, of which one has been designed for the realistic simulation of down-hole pressure conditions. HIGH-PRESSURES MACHINE In this machine (diagramed in Fig. 1) the mud, pore and confining pressures can all be adjusted independently. The foil-covered rock sample contained in the inner pressure vessel is confined by oil that is pressurized by means of a hand pump. The pore space of the watersaturated sample is connected to an arrangement which keeps the pressure in the pore space constant regardless of the rate of filtrate flow through the sample.

By V. L. Elliott, C. L. Meyette

The conditioning of semifinished steel products such as billets, blooms, and slabs to remove surface defects before further processing to finished products is a necessary accompaniment to steel mill rolling operations. A knowledge of the kinds of defects which occur and of the conditions in melting, teeming, and rolling that may lead to their occurrence is favorable to the production of quality products. Surface defects may be classed as either of mechanical origin such as those that occur in the heating and rolling operations and include breaks, tears, guide marks, mechanical laps and the like, or they may have been in the ingot before heating and rolling. Examples of the latter are ingot cracks, blow-holes, scabs, and inclusions which lead to the numerous known types of seams and surface flaws. Most of the common types of surface defects and methods for their identification by visual examination or by the aid of macro-etch tests are well known. The conditions which caused their formation are also appreciably understood and this knowledge has been instrumental in the establishment of methods for metallurgical control. There are, however, defects of doubtful origin. In any endeavor to trace the causes for their occurrence, the question of first concern is: I. Whether they were formed in the rolling procedure. 2. Whether they existed in the ingot prior to rolling. In the case of semifinished products which are rerolled to finished products there is also the question of whether they were formed in the primary or in the secondary rolling. In metallurgical laboratories where numerous or routine examinations of the quality of rolled products are made over the course of time, there will doubtless be many puzzling cases of defect origin. Microscopic examination of the defects may, however, reveal a characterizing condition that can be used to classify them broadly with respect to their origin. Such a condition has been observed and, after detailed investigation, is described here with the thought that it may offer a usable and relatively simple solution to a bothersome problem. Basis For Classifying In this discussion the term "mechanical type defects" will be used to designate those that have occurred as a result of the rolling operations such as in rolling from the ingot to billets, blooms, or slabs or in rerolling to finished products. The term "steel type defects" will be used to designate those that were present in the ingot prior to primary rolling or that were in the semifinished product prior to secondary rolling to finished product. The basis for distinguishing between the two types of defects lies in the relative degree of subscale formation surrounding them. Subscale is defined1 as a zone of

Jan 1, 1949

By J. Clair, H. Mirabel

The determination of the temperature and electrical potential distributicms in the cathodes of aluminum electrolytic cells is difficult. The reascms come from the various nature and the intricate three-dimensional geometry of the materials; besides thermal and electrical phenomena react upon each other. A method of calculation using a computer program applied to a mathematical model, figuring the cathode, is developed. Both of the thermal and electrical phenomena are simultaneously considered. Temperature and electrical potential distributions are finally obtained by successive iterations. Results are compared with measurements on industrial cells. Theoretical and practical applications of these studies are given. Up to the present time the study of the distribution of the temperatures and electric potentials in the electrodes, anode and cathode, of the electrolytic cells used for the production of aluminum was limited to one of the two aspects of the phenomena because of lack of a simultaneous method of calculation. For example, the anode or cathode drop was studied assuming that the temperatures in the iron and carbon are known, a method that obviously is very approximate since iron resistivity, in particular, greatly varies with temperature, which in turn depends on current density. Consequently we tried to find a method of calculation simultaneously taking into account both thermal and electrical phenomena. We proceeded to the study of the cathodes as an initial approach to the problem. Although the cathode and surrounding materials may have varied forms and particularly very heterogeneous characteristics, their structures are simpler than that of the Sijderberg anode and boundary conditions are more easily represented than in the case of anodes even though they are prebaked. The study was in two parts: a) development of a model schematizing the true geometry of a cathode and defining the thermal and electrical boundary conditions, and b) working out a method of calculation of the temperatures and potentials by means of an electronic computer. To facilitate solution of the problem, a model was used initially much simplified in comparison with an actual cathode. This model permitted development of the method of calculation. In a second phase, this model was adjusted to the study of actual cathodes and applied to different types of cells: low- or high-intensity cells, cells set up at ground level or above ground level, cells with cathodes more or less heat-insulated. Simultaneously measurements were made with cells equipped with cathodes of the types studied to compare the values resulting from calculation. The initial model was also used for general studies, in particular for studying the effects of current density in the carbon and iron. The results were confirmed or made precise by the model of the true cathodes. This report successively describes: a) the manner in which the model representing a cathode was worked out, with the simplifications and/or the hypotheses used, b) the method of solution of the problem by means of the electronic computer, and c) an example, stating the extent to which the results obtained may be realistic. Further the possibilities offered by such a study are examined. 1) CATHODE REPRESENTATION The purpose of this phase is to represent the cathode in the form of a so-called "mathematical model", that is with a simplified geometrical configuration, in order to meet the subsequent calculation requirements, while keeping to the true facts as closely as possible. This model further includes the thermal and electric conductivities with regard to temperature for the varied materials composing the cathode, as well as the thermal and electrical conditions at the model boundaries. 1.1) Guiding Principles. For calculating the temperatures and potentials the model is divided by trior-thogonal planes into a network of small elementary parallelepipeds. At the summit of these parallelepipeds' so-called mesh points, the temperatures and potentials are computed. The number of mesh points is of course limited by the capabilities of the computer, since 1) the number of equations to be solved depends on the number of mesh points selected, and 2) the amount of time spent by the computer considerably increases with increasing this number. These conditions call for the following requirements as concerns the model: a) Dimensional requirements: the calculation will be all the more accurate as the network is more closely meshed. Since the number of mesh points is limited in practice, it is necessary to restrict the dimensions of the model. b) Geometrical requirements: so as to make things easier in working out the network, the model must be given a simple geometry. In particular, it will be convenient to have the cathode so constituted that the surfaces limiting the cathode and the surfaces within the cathodes separating the different materials consist of triorthogonal planes. 1.2) Schematization of the Cathodes. After the tech-

Jan 1, 1968

By R. G. Agarwal, Ramey Jr. H. J., Al-Hussainy R.

Although it has long been realized that gas recovery from a water-drive gas reservoir may be poor because of high residual saturations under water drive, it appears that only limited infomlation on the subject has been available until recently. This study was performed to show the qiiantitative potential importance of water influx. Results indicate that gas recovery may be very low in some cases: perhaps as low as 45 per cent of the initial gas in place. Gas recovery under water drive appear to depend in an important was on: (I) the prodirction rate and manner of production; (2) the residual gas saturation; (3) aquifer propertie.); and (4) the volumetric displacement effciency of water invading the gas reservoir. The manner of estimating water-drive gas reservoir recovery can vary considerably. Examples are: the steady-state tnethorl. the Hurst modified steady-state method, and various unsteady-state methods such ac. those of van Ever-dingen-Hurst, Hurst, and Carter-Tracy. The Carter-Tracy water influx expression was used in this study. In certain cases, it appears that gas recovery can be increased significantly by controlling the production rate and manner of production. For this reason, the potential importance of water influx in particular gas reservoirs should he investigated early to permit adequtrtr planning lo optirtize the pay reserves. INTRODUCTION In recent years, the economic importance of natural gas production has become increasingly apparent. This has been evidenced by more intensive exploration efforts aimed at gas production, and exploitation of both deep, as well as low-permeability gas reservoirs. Technical developments such as deep-penetration fracturing have made development of such formations economically feasible. Unfortunately, water influx has forced abandonment of a number of gas reservoirs at extraordinarily high pressures. Although reservoir engineering methods for estimating water influx have long been available, it appears that application of these methods to the water-drive gas reservoir has been sporadic.'a Available methods for estimating water influx which can be applied to the water-drive gas reservoir problem include the steady-state method,1 the Hurst modified steady-state method and various unsteady-state methods such as those of van Everdingen-Hurst. Hurst, and Carter-Tracy. Interesting applications of these solu- tions to gas reservoir and the aquifer gas-storage problems have appeared recently.3,12,14 The experimental study of residual gas saturations under water drive by Geffen et al. in 1952 indicated that residual gas saturations could be extremely high. A value of 35 per cent of pore volume is often used in field practice when specific information is not available. The study of Geffen et al. showed that residual gas saturation might be much higher in some cases. Naar and Henderson concluded that the residual non-wetting phase saturation under imbibition should be about half of the initial non-wetting phase saturation. The Naar and Henderson result that residual gas saturation under water influx should be about half the original gas saturation is recommended as an estimate if laboratory measurements are not available. Thus, it is clear that a considerable portion of the initial gas in place might be trapped in a water-drive gas reservoir as residual gas at high pressure. A full water-drive would result in loss of residual gas trapped at initial reser.voir pressure. Consideration of transient aquifer behavior leads to the conclusion that high-rate production of water-drive gas reservoirs could result in improved gas recovery by reduction of the abandonment pressure. However, there appears to be little quantitative information on this possibility. One of the few advantages of water-drive gas production appears to be improved deliverability through water-drive support of the reservoir pressure. There may also be an advantage in higher condensate recovery caused by pressure maintenance for gas-condensate water-drive reservoirs. In view of the preceding, this study was made to assess the potential importance of water-drive in gas reservoir engineering. The Carter-Tracy approximate water-influx expression was used because this equation offers some advantages in hand-calculation which do not appear to have been generally recognized.' However, calculations were performed in the main with a high-speed digital computer to permit evaluation of the effect of water-drive under a large variety of conditions. CALCULATION METHOD Water-drive gas reservoir performance can be estimated in a manner completely analogous to oil reservoir calculations: a materials balance is written for the reservoir, and a water influx equation is written for the aquifer. Siniltaneous solution provides the cun~ulative water influx and the reservoir pressure. When reservoir performance data (gas produced and reservoir pressures) are available, it is usually possible to match performance data to determine the initial gas in place and the water influx parameters —

Jan 1, 1966

By V. L. Elliott, C. L. Meyette

The conditioning of semifinished steel products such as billets, blooms, and slabs to remove surface defects before further processing to finished products is a necessary accompaniment to steel mill rolling operations. A knowledge of the kinds of defects which occur and of the conditions in melting, teeming, and rolling that may lead to their occurrence is favorable to the production of quality products. Surface defects may be classed as either of mechanical origin such as those that occur in the heating and rolling operations and include breaks, tears, guide marks, mechanical laps and the like, or they may have been in the ingot before heating and rolling. Examples of the latter are ingot cracks, blow-holes, scabs, and inclusions which lead to the numerous known types of seams and surface flaws. Most of the common types of surface defects and methods for their identification by visual examination or by the aid of macro-etch tests are well known. The conditions which caused their formation are also appreciably understood and this knowledge has been instrumental in the establishment of methods for metallurgical control. There are, however, defects of doubtful origin. In any endeavor to trace the causes for their occurrence, the question of first concern is: I. Whether they were formed in the rolling procedure. 2. Whether they existed in the ingot prior to rolling. In the case of semifinished products which are rerolled to finished products there is also the question of whether they were formed in the primary or in the secondary rolling. In metallurgical laboratories where numerous or routine examinations of the quality of rolled products are made over the course of time, there will doubtless be many puzzling cases of defect origin. Microscopic examination of the defects may, however, reveal a characterizing condition that can be used to classify them broadly with respect to their origin. Such a condition has been observed and, after detailed investigation, is described here with the thought that it may offer a usable and relatively simple solution to a bothersome problem. Basis For Classifying In this discussion the term "mechanical type defects" will be used to designate those that have occurred as a result of the rolling operations such as in rolling from the ingot to billets, blooms, or slabs or in rerolling to finished products. The term "steel type defects" will be used to designate those that were present in the ingot prior to primary rolling or that were in the semifinished product prior to secondary rolling to finished product. The basis for distinguishing between the two types of defects lies in the relative degree of subscale formation surrounding them. Subscale is defined1 as a zone of

Jan 1, 1949

By R. Dawson Hall

LONG regarded as nearly worked out, the anthracite region still shows promise of a hundred years of life, for means are being found to get bottom, top, pillar, and other coal that earlier generations disregarded as too expensive to mine. Rock drivages and, still more, machinery are making it possible to get such coal. Mechanical methods enable the owner of thin beds to mine these with profit, and the miner recognizes that he must permit the use of machinery or the inexorable laws of economics will deny him opportunity to work. E. L. Dana, Jr., well outlines this situation, which in the past year became definitely established. Stripping also is recovering, safely and inexpensively, coal that past generations regarded as too hazardous and costly for mining.

Jan 1, 1935

By W. L. III McMorris, R. E. Zimmerman, Michael Sokaski, E. R. Palowitch, M. R. Geer, C. E. Capes, A. W. Deurbrouck, S. C. Sun

PART 1: DENSE MEDIUM SEPARATION by M. SOKASKI, M. R. GEER, and W. L. MCMORRIS III INTRODUCTION In the early days of coarse-coal treatment by the dense-medium process in Europe, loess was one of the materials used for medium solids. Newly developed cyclones were used to reclaim and thicken the loess suspension. On occasion, when the cyclone thickener at the Maurits mine in the Nether- lands plugged, the overflow was found to be filled with clean coal free of impurity. From this observation stemmed the concept of the cyclone as a cleaning device. Development took place during World War I1 in the lab- oratory of the Dutch State Mines under the direction of M. G. Driessen. A 15 tph (13.6 mt) pilot plant was in operation in the laboratory by 1945, when, in September, Driessen made the first public disclosure of the process in a paper presented to the Institute of fie1 in London. In April 1945 operation of this pilot plant was observed by H. F. Yancey, who was so

Jan 1, 1979

By Clarence S. Ross

INTRODUCTION THIS chapter on the rô1e of physical-chemical processes in ore deposition presents unusual difficulties because it attempts to discuss the theory of processes that are very imperfectly under- stood, but which are among the most fundamental problems now before the student of ore formation. It is generally believed that a great variety of ore deposits are in some way derived from igneous rocks; but we desire to know the mechanism of their splitting off from the parent magma, the physical and chemical character of the material that acts as a medium for transfer from magma to the point of deposition, the manner of deposition, and the methods of replacement and removal of the invaded rocks. This problem is difficult for the field geologist because it concerns forces that for the most part have long since ceased to act. It involves a complex system of which the time for completion extends from the first development of the parent magma through its intrusion, its slow cooling and crystallization, and the final escape of its last residuum, a time probably represented by millions of years. In space the processes extend from profound depths of the abyssal magma which can never be directly observed, through the horizons characterizing deep-seated igneous rocks and ore deposits; those formed at moderate depths; and ends with surficial ones and surface thermal springs. The geologist usually can study the effect at but one of these horizons: he must attempt to fit his puzzle together while seeing but a few parts at a time. Thus he must deal with many isolated phenomena, as if they were the result of many physical and chemical systems; when in fact his problem involves a single exceedingly complex system, and will only be understood when that entire complex system is understood. The geophysicist is handicapped because he must attempt to interpret an extraordinary complex system, involving physical and chemical conditions which he can never hope to duplicate fully, through the study of many exceedingly simple systems.

Jan 1, 1933

By E. P. Abrahamson, S. L. Lopata

A general relalionship between the amount of glide shear (due to slip) and the macroscopic shape change has been developed. Since the deformation can be large, finite strain analysis is employed. In this treatnzent, the shape change is expressed by a deforlnation gradient matrix, F - [axi/aXj/ where X and x refer lo the initial and final positions of a particle. This matrix is readily evaluated in termas of the amounl of glide shear, a , and the direction cosines of the slip-plane normal and the slip direction for a single active slip systena. In the case of deforma tion from slip on several systems, the product F(a) of the several deformation gradient matrices is first calculated. Then, by assuming that the final configuration is reached by a long series of small shears of magnitude a, occurring more or less alternately in the several slip sys- IN problems of crystal plasticity, it is often necessary to relate the amount of glide in the operating slip systems to the macroscopic strain components. This relationship is relatively simple when only small strains are considered. In this case the separate strain contributions from several slip systems are additive. Such a procedure is incorrect in the case of large plastic deformation. To the authors' knowledge, no general treatment of the latter problem has appeared in the literature. In specific instances, Mark, Polanyi, and schmid3 have derived the relationship between glide and axial elongation during tensile pulling of a single crystal when only one slip system is active. A similar relationship for duplex slip was worked out by v. Göler and Sachs.4 Taylor and Elam1 have also studied in detail problems of large plastic deformation. Due to uncertainties as to the slip systems at the time, ! terns, the final deformation gradient matrix can be obtained. Mathematically, the problem is reduced to finding the limit of F(aN as N — m while a — 0 in such a way that the Product Na = a finite conslant designatzng the accumulated amount of shear. It turns out that this limit is simply eafF1, where F, is the matrix whose elements are the coefficients of a in the F(a) twatrzx. Application is made of the present treatment to a fcc crystal of Permalloy compressed on the (110) plane and contrained to elongate in the [112] directzon. In addition, it is shown that one rnay readily obtain from the general analyszs the well-known formulas relating elongation, amount of glide shear, and amount of lattice rotation for crystals deforming by single and double slip under tension. however, they were mainly concerned with proving that slip occurs on {111}(110) systems in fcc metals. The present general treatment arose out of recent investigations of magnetic anisotropy in cold-worked Fe-Ni alloys6 as well as some related problems in strength anisotropy of single crystals.' Detailed application of the general analysis will be provided in the case of a Permalloy single crystal compressed on the (110) plane and constrained to elongate only in the [112] direction. It will be seen that, as expected, the small strain approximation leads to significant errors after moderate straining. It will also be shown that the present general treatment yields the formulas of Mark et al. and of v. Goler and Sachs in those specific cases. GENERAL CONSIDERATIONS Consider a homogeneous deformation in which a material point initially at moves to (xl,xz,x3), both positions being referred to the same set of Cartesian axes. Such a deformation can be

Jan 1, 1967

By Henry S. Burnholz, Charles Y. Clayton, Francis B. Foley

This work was first undertaken for the U. S. Bureau of Mines, in 1919-20, by C. E. Julihn, superintendent of the station at Minneapolis. Learning of the interest, in this subject, of B. F. Tillson, of the New Jersey Zinc Co., Mr. Julihn and Mr. Foley went to Franklin, N. J., and discussed the matter with him. A conference in Chicago, in November, 1920, was attended by Dr. F. G. Cottrell, who was then Director of the Bureau of Mines, and representatives of the Bureau of Mines and of the hlissouri School of Mines and Metallurgy; at this time a cooperative plan of work was agreed upon by the Bureau of Mines and the Missouri School of Mines. In February, 1921, Mr. 'Tillson arranged a conference on this subject at the time of the annual meeting of the American Institute of Mining and Metallurgical Engineers, at which several technical papers were presented. In a paper, the Breakage and Heat Treatment of Hock Drill Stcels, he suggested a program that might be carried out in connection with the investigation of the problem. At this conference Mr. Manning, former Director of the Bureau of Mines, suggested the formation of an advisory committee to the Bureaus of Mines and of Standards for prosecution of this investigation. On Feb. 20, 1922, a secoud conference in New York, at the time of the annual meeting of the American Institute of mlining and Metallurgical Engineers, was attended by representatives of various technical societies. At this meeting, the report of Nov. 20, 1921, of the Chiefs of Divisions of Metallurgy of the Bureaus of Mines and of Standards, was discussed and it was agreed: 1. That the survey recommended by the two bureaus should be undertaken, which survey would have for its object the ascertaining of the present status of the practice of the heat treatment of drill steels, the extent to which the breakage occurs, etc.; and 2. That a report should be presented, of the findings of those who made the survey, to the Advisory Board to the Bureaus of Mines and of Standards. The Bureau of Standards assigned $4000 to the prosecution 01 a three-months' survey, which was carried out in April, May, and June, 1922, of about sixty mines

Jan 1, 1923

Apparatus and a method for determining the volumetric behavior of hydrocarbons at pressures up to 10,000 psia and at temperatures between 0° and 460°F are described. The equipment is suitable for measuring the total volume of the system and the volume of a liquid phase as functions of state within these ranges of temperature and pressure. Introduction During the past two decades there has been a marked increase in the ranges of temperature and pressure encountered in underground hydrocarbon reservoirs of commercial interest. In addition, greater interest in the intensive characteristics of the fluids found in these reservoirs has developed. Apparatus Several types of apparatus have been developed in the authors' laboratory for volumetric measurements of hydrocarbon systems. The earliest equipment described1 was characterized by constant volume, and the weight of material present was varied systematically in order to attain the different pressures desired in the study. Later another apparatus2 was built in which the effective volume of the cylindrical cell, which confined a hydrocarbon sample of constant weight was varied by injection or withdrawal of mercury. The effective total volume of the equilibrium cell was measured by ascertaining the position of the mercury surface but no measurement could be made which gave knowledge of the volumes of individual phases existing within the hydrocarbon system. A third apparatus3 was designed for use at higher pressures and temperatures than the earlier equipment would tolerate. This apparatus was of the variable volume type but was built in the general form of a U-tube, the mercury level being measured at the surface which was not exposed to the hydrocarbon system. This arrangement avoided the need of subjecting measuring equipment to the extremes of temperature at which studies were made, but it gave no provision for measurement of the volumes of individual phases. Although this last apparatus was satisfactory as to accuracy and convenience for many purposes, need was felt for measurements of the volume of the liquid phase of the hydrocarbon system. For this reason a fourth equilibrium apparatus was designed and constructed, and it is the purpose of the present paper to describe it. The equilibrium cell has a working range of temperature from 0° to 460°F at pressures up to 10,000 psi. Provision for measurement of both total volume and liquid-phase volume makes it particularly suitable for the equilibrium study of heterogeneous systems consisting either of simple mixtures or of complex field samples of hydrocarbons. The general arrangement of the ap-

Jan 1, 1948

By Charles Y. Clayton, Henry S. Burnholz, Francis B. Foley

This work was first undertaken for the U. S. Bureau of Mines, in 1919-20, by C. E. Julihn, superintendent of the station at Minneapolis. Learning of the interest, in this subject, of B. F. Tillson, of the New Jersey Zinc Co., Mr. Julihn and Mr. Foley went to Franklin, N. J., and discussed the matter with him. A conference in Chicago, in November, 1920, was attended by Dr. F. G. Cottrell, who was then Director of the Bureau of Mines, and representatives of the Bureau of Mines and of the hlissouri School of Mines and Metallurgy; at this time a cooperative plan of work was agreed upon by the Bureau of Mines and the Missouri School of Mines. In February, 1921, Mr. 'Tillson arranged a conference on this subject at the time of the annual meeting of the American Institute of Mining and Metallurgical Engineers, at which several technical papers were presented. In a paper, the Breakage and Heat Treatment of Hock Drill Stcels, he suggested a program that might be carried out in connection with the investigation of the problem. At this conference Mr. Manning, former Director of the Bureau of Mines, suggested the formation of an advisory committee to the Bureaus of Mines and of Standards for prosecution of this investigation. On Feb. 20, 1922, a secoud conference in New York, at the time of the annual meeting of the American Institute of mlining and Metallurgical Engineers, was attended by representatives of various technical societies. At this meeting, the report of Nov. 20, 1921, of the Chiefs of Divisions of Metallurgy of the Bureaus of Mines and of Standards, was discussed and it was agreed: 1. That the survey recommended by the two bureaus should be undertaken, which survey would have for its object the ascertaining of the present status of the practice of the heat treatment of drill steels, the extent to which the breakage occurs, etc.; and 2. That a report should be presented, of the findings of those who made the survey, to the Advisory Board to the Bureaus of Mines and of Standards. The Bureau of Standards assigned $4000 to the prosecution 01 a three-months' survey, which was carried out in April, May, and June, 1922, of about sixty mines

Jan 1, 1923

By Charles White Merrill

Money is one of the most pervasive elements in human life. The compensation for a workman's daily efforts is expressed as a wage and is measured in money. What an individual may consume depends largely on his income which also is expressed in terms of money. If he would start an enterprise its size would be determined in large part by the amount of money available for capitalization and its success would be measured in net income expressed in money. In short, the most widely used common de- nominator for comparing merchandise, real property, jobs, enterprises, gross national product, or personal success is money. Despite this use of money by almost everyone past infancy to express his appraisal of the innumerable values he sees around himself, the complexity of the device called money makes its nature and workings a mystery to most users. Some of the difficulty in understanding money results from the fact that it has three distinct but interrelated functions: (1) a medium of exchange, (2) a unit of account, and (3) a store of value. In many statements about money the discussion moves from one function of money to another without the speaker or the listener recognizing the changes. For example, the housewife says "We took the money we had saved up to make the down payment and after twelve monthly payments the television will be ours." When this housewife spoke of "saving up the down payment" she referred to money in its function as a store of value; when she spoke of "the down payment" she was using money as a medium of exchange; and when she referred to the "monthly payments" she spoke of money as a unit of account. Another cause of confusion in understanding money is its paradoxical nature in that it represents both the power to produce and the power to consume. For example, when the rich uncle dies one nephew may regard his inheritance as an opportunity to buy a farm and leave the ranks of the wage earners to become an independent producer, whereas the other nephew may regard his portion as the means of living in complete leisure as a pure consumer.

Jan 1, 1964

By C. H. Hitchcock

The puiblication by the Institute of a small geological map of the United States calls for an explanation of its peculiarities. The title intimates that it is intended "to illustrate the schemes of coloration and nomenclature recommended by the International Geological Congress." By way of further explanation it is said to be "based, by permission of the Director of the United States Geological Survey, upon the map published in his Fifth Annual Report, the portions not colored in that map being here supplied from other sources." The map referred to was prepared by W. J. McGee, and in the text of the report containing it he has given a list of the authorities employed in the compilation. The scheme of coloration used for the map was the one proposed by the Director, in the Seeond Annual Report, for the publications of the United States Geological Survey, which differed materially from those employed by the older American geologists. Because of the increasing diversity in the particular colors employed to represent rocks by geologists in different countries, and of the existence of very dissimilar schemes of nomenclature, it seemed best to the American Association for the Advancement of Science, at its Buffalo meeting in 1876, to appoint an international committee of geologists, who should consult together, and, if feasible, to call an International Congress to discuss these subjects. The proposition met with favor, and the meeting was called. The first session was held at Paris, in 1878, when geologists were present from twenty different countries. Once organized, the Congress has perpetuated itself, enacting regulations for its conduct, choosing the French language for its medium of communication, and arranging for the compilation of a geological map of Europe upon which the perfected schemes of coloration and nomenclature will be delineated. The American Association maintains a standing committee to represent it at the international sessions, and to report their proceedings. Sixteen countries were represented at the second Congress, at Bologna;

Jan 1, 1887

By Charles S. Robinson

The Henderson ore body is east of the Continental Divide in the Front Range of the Colorado Rocky Mountains, about 80 km (50 miles) west of Denver. The ore body is being developed for mining by workings that extend more than 1100 m (3500 ft) below the topographic surface. During construction of the mine workings, ground water in fractures in cystalline rock has been encountered. From 1969 to 1973, Charles S. Robinson & Associates, Inc., in cooperation with the engineering and geologic staffs of the Climax Molybdenum Company, a division of Amax Inc., studied the ground water geology of the Henderson mine development area. Detailed geologic record( of the Henderson mine were available as a result of the exploration, evaluation and development of the mine. Records of the flow, chemical composition and temperature of the ground water at and near the surface, from the entire mine, from portions of the mine, and from exploration holes drilled in the mine, were kept as the mine was developed. Where possible, ground water pressures in drill holes and changes in pressure with time, were recorded. The geologic, hydrologic and chemical data were correlated. The following conclusions were drawn from the correlations: The ground water in the Henderson mine occurs in fractures in Precambrian igneous and metasedimentary rock and in a series of Tertiary intrusive rocks. Two zones of ground water were recognized; an active zone, in which the fracture systems are recharged and discharged annually into the surface water system, and a passive zone, in which the fractures were filled with water in the geologic past. Discharge from the passive zone is through mine workings that intersect the fracture systems. Discharge from a fracture or fracture system is initially high but decreases with time. The rate of decrease in flow (or pressure) is exponential. By measuring the change in flow with time, it is possible to calculate the amount of flow at some given period of time in the future. Based on changes in rate of flow and pressure, and the geology, and assuming rates of mining of the ore, it will be possible to predict the volumes of water that will have to be handled during the life of the mine and the area around the mine that will be drained by the mining operation.

Jan 1, 1979

By T. M. Morris, F. M. Lewis, W. C. Lay, Gordon M. Bell

Part I of this chapter is concerned with the description of and metallurgical data pertaining to the flotation circuits used in the London mill of the Tennessee Copper Co., at Copperhill, Tenn. The ores treated at the London mill are massive complex sulfides, in which pyrrhotite and pyrite are the predominant minerals. Other sulfides are chalcopyrite and sphalerite; magnetite is also of economic value. The approximate mineralogical analysis of the ore is shown in Table 1. [ ] The chalcopyrite and sphalerite are closely associated with pyrrhotite as shown by the tracings of micrographs (Fig. I), which are representative of the mill feed. Fig. la illustrates the type of locking between pyrrhotite and chalcopyrite; Fig. lb illustrates the way in which sphalerite is attached. Thesephotographs indicate that it is not practical to break all of these attachments. Hence, in order to produce concentrates with satisfactory grades and recoveries, most of the locked chalcopyrite particles must be recovered into the copper concentrate, and the locked sphalerite-pyrrhotite particles must be separated from the iron concentrate. A copper concentrate, a zinc concentrate, and an iron concentrate are made. Typical metallurgical results are tabulated in Table 2. HISTORICAL In 1922 the London mill started as a copper concentrator, with a capacity of 300 tpd, and in 1926 an additional flotation circuit was added to recover the iron sulfide remaining in the copper tailing. In 1927 a zinc flotation circuit was installed between the copper and the iron flotation circuits. This procedure was not satisfactory because the iron recovery was low, due to the

Jan 1, 1962

By Paul L. Burkhart

THOUGH at an earlier period brief studies had been made by the Lehigh Navigation Coal Company Inc., it was not until 1924 that J. B. Warriner, then general manager, called for a comprehensive study of timber treatment, treating solutions, and related operations. Because of the impossibility of procuring accurate costs and other pertinent treating data, the American Wood Preserving Co. agreed to treat a car of mine timber at the Port Reading plant of the Reading Railroad. Fig. I shows the treating data collected at the treating plant on this timber, which was installed in two of the Lehigh mines in 1925. [ ] In the latter part of 1925, a survey of the tunnels and gangways of the company's Panther Valley mines was made to determine the proportion of gangways or tunnels timbered, cause of timber failures, approximate life of the average wood set and the approximate percentage of treated timber that it would be profitable for the company to use. Results of this survey appear in Table I. Because of the high percentage of timber that gave evidence of failure by rot, as noted in Table I, and a further study of the life of the sections where timbering was necessary, it was deemed advisable to fill 25 per cent of the yearly gangway timber requirement with treated timber. QUANTITIES AND TREATMENTS OF TREATED TIMBER PURCHASED In the early days of the program, none of the large treating companies would accept orders for small quantities of treated timber and the company was compelled to state the quantity of timber it would require at each operation in each month of the year. Table 2 is an example of the tabulation given to the various treating companies to assist them in making a yearly bid on the minimum quantity of timber required by the company during the year 1931. A bill of timber was calculated for each car, the weight of which would be between the minimum and maximum weight permitted for railroad-car loading. The treating company was paid for timber upon delivery at the operation specified. As extra cars of timber were required, they were ordered from the treating company, and payment was required on their receipt, on the basis of the piece or tonnage

Jan 1, 1942