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By F. Cadena

Hiwassee Darn, now under construction by the Tennessee Valley Authority on the Hiwassee River, a tributary of the Tennessee River, will require aggregate for approximately 800,000 cu. yd. of concrete. Near the damsite deposits of natural sand or gravel are not available and graywacke, a rock that is found in abundance, suggested itself as a likely source of manufactured aggregate. Graywacke is a metamorphosed sandstone composed principally of a mixture of quartz (65 per cent), mica (25 per cent), and feldspar (10 per cent). Other minerals are present in negligible amounts. The rock varies in different parts of the quarry from very fine to a coarse grain containing particles of about ¼ in. maximum size, although the bulk of the deposit is medium grain. Extensive tests showed that graywacke would be suitable as a source of both coarse and fine aggregates. The aggregate plant available for use at Hiwassee Dam consisted of the coarse-aggregate and sand plant used on the Norris project. The coarse-aggregate plant had also been used at Chickamauga Dam. Although most of this plant equipment is now in use at Hiwassee, the present flowsheet is not only different from that at Norris and Chickamauga but is also unique as compared to the flowsheet of the average crushed-stone aggregate plant. It is hoped that this paper will show the importance of proper arrangement of equipment if the optimum in flexibility and capacity is to be attained. Flowsheet Rock is ioaded by 3-yd. electric shovels into 12-yd. dump trucks, which carry the rock to the primary crusher, a 42-in. Superior McCully gyratory unit set at 4¾ in. (Fig. 1). The primary crusher discharges directly onto a 42-in. inclined belt conveyor, which carries the product to a surge storage pile with a maximum live storage capacity of approximately 3000 tons. A concrete tunnel under this storage pile houses the feed end of a 36-in. belt conveyor (conveyor B) fed by a 36 by 66-in.

Jan 1, 1942

By L. D. Rickets

The principles on which an art is founded are usually few and necessarily basic in nature, but he who wishes to achieve the power to select his aides and give success to important undertakings that may be entrusted to him in the future must ordinarily undergo years of drudgery in order to gain the experience that will enable him to distinguish such fundamentals through the haze of reenforcing detail that clothes and tends to disguise them. This especially applies to those who would dream dreams that may come partly true. Professor Henry B. Cornwall of Princeton was a graduate of Freiberg with mining experience in Mexico. He was my friend and mentor during my college life. In 1883 I finished my postgraduate course and had two offers of work to consider. His advice is very clear in my mind today. It was essentially as follows: I know something of the mines of Mexico and have crossed through the mountains of the West. The West possesses a vast area of mountain and valley. California has long had its gold mines, the Comstock and Gilpin County followed and now comes the discovery of Leadville. I believe the West, will become a great mining country. You can choose now to teach here or go to the mountains. Were I in your place I would go West and identify myself with mining.

Jan 1, 1932

By C. M. Nickerson

IT is apparent that repressuring of the oil measures is becoming increasingly important to the oil industry, and is a matter that warrants the best efforts of the petroleum engineer charged with applying this method of operation to a producing property. Considerable attention has. been directed to repressuring in various California oil fields, such as Dominguez and Seal Beach, which have served to sell the more progressive operator on this idea and also to keep him sold. The projects that have received most attention are in comparatively young fields where the fluid levels are high, the wells, perhaps, still flowing, where the wet gas production is of considerable volume, and where there is vital need of immediate conservation of gas, which otherwise would be blown to the air. The new State of California Gas Law, which prohibits the waste of gas, has served to interest the oil industry in -means of conserving the gas that is now being blown to the air because of lack of markets. This vitally affects the operator in the older, well-depleted oil fields of the state, because in many cases he has a limited market for gas, on account of the flush production from the more active oil fields. While the waste of gas is relatively small in these older fields, such as the Midway-Sunset area, it now attains considerable importance, since under the new State Gas Law it must be put to some beneficial use. Repressuring in the older fields of California has not received the attention of the petroleum engineers that is warranted by the present situation. This paper was prepared with the view of presenting the salient features connected with repressuring in the well-depleted oil measures of the older fields, and to show what results have already been obtained in these fields by injecting the unmarketable. gas into the sands, particularly in the Midway-Sunset field in the San Joaquin Valley of California. Other projects in the older fields of the state offer some supporting data in this connection, such as the Shields Canyon and the Brea Canyon fields.

Jan 1, 1929

By Thomas Fraser, Robert MacLachlan

The dry cleaning of coal is a relatively new art and, as might have been expected, a number of unforeseen problems have been brought to light in the few years that dry methods of treatment have been in commercial use. The pneumatic concentrators that were first adapted to the cleaning of coal had already been developed to a fair degree of efficiency, although at low ratings, in the field of ore dressing. The concentrating machines, therefore, were in a relatively more perfected state than the general technology of dry cleaning and, for this reason, the major difficulties encountered in the early plants were in the accessory operations involved in the servicing of the cleaners rather than in the functioning of the cleaners themselves. The crudities of a new technology were further aggravated, in some cases, by meagerness of appropriations which precluded even the provision of adequate storage bins and such other facilities as had been long recognized as indispensable to the proper functioning of older types of cleaning plants. The practice of dry cleaning is now sufficiently established so that we may examine critically auxiliary equipment and operations. The cleaning processes have been so simplified, with respect to presizing of the raw coal required and the quantity of air circulated, that stinting of expenditures for auxiliary equipment is not necessary to keep the per ton cost of installation in line with complete and well designed plants of other types. Furthermore, sufficient operating experience has been accumulated to ascertain the conditions most conducive to effective operation of dry-cleaning machines; at least the essentials of a definite technology of dry cleaning has been established. Early Operating Problems The problems that have occupied the builders and operators of dry-cleaning plants from the beginning have been relatively few, but difficult of solution. The principal difficulties have been: 1. The proper sizing of the raw coal to suit the cleaning process. 2. The handling of raw coal when it is delivered wet from the mine. 3. Dust collecting. 4. The maintenance of uniformity in cleaning performance.

Jan 1, 1931

By G. L. Oldright, Henry de Rycker, S. F. Ravitz

The upper limit of richness of concentrates that can be smelted by means of the blast furnace without added diluents is fixed by the operation of sintering. A sinter feed with normal gangue constituents, containing more than about 50 per cent of lead, tends to fuse; as a result, air does not come sufficiently into contact with the sulphides at roasting temperatures, and sulphur elimination is poor. Since most lead concentrates now contain 55 to 80 per cent lead, it is necessary to add diluents to lower the grade of such sinter feed to about 50 per cent or less. This not only entails the expense of providing barren diluents when adequate diluents containing precious metals are not available but also appreciably lowers the capacity of the blast furnace to produce lead and increases slag losses. Attempts to desulphurize rich lead concentrates by methods other than sintering have not proved successful. Flash roasting, for example, converts much of the lead sulphide to lead sulphate rather than to oxide. However, this suggested the possibility that deliberate flash roasting of the concentrates to sulphate, followed by sinter roasting of the resulting product, might prove promising, particularly inasmuch as the elimination of sulphur from lead sulphate requires heat alone and not contact with atmospheric oxygen. The sintering of lead sulphate products has additional interest because important amounts of such products are now treated by lead smelters. Considerable quantities of lead sulphate are present in rich lead flue dusts and other by-products; lead-chamber sulphuric acid plants and other

Jan 1, 1944

By H. L. Eiselstein, F. P. Huston, B. B. Betty

An extensive program for the establishment of creep data on high-nickel alloys has been in progress during the past seven years. This paper presents the accumulated data on two solid solution alloys, cold-drawn, annealed Monel and cold-drawn, annealed Inconel. Data on these two alloys in other conditions will be published at a later date. Monel, a nickel-copper alloy, is normally considered a corrosion-resistant material, but it will be shown that it also has considerable creep strength, validating its use at temperatures up to and including 900°F. Inconel, a nickel-chromium-iron alloy, is definitely a heat-resisting alloy possessing good creep strength and oxidation resistance up to iiooOF., and because of its oxidization resistance has been used successfully at much higher temperatures for lightly stressed parts. The literature contains but meager data on the creep properties of high-nickel alloys. Howevcr, Bennett and McAdam have presented a substantial quantity of creep data for cold-drawn Monel.1 The material as tested was not representative of mill production for it was cold-drawn to a reduction of area of 40 per cent as against 13 per cent, which is the mill standard for Monel. Twenty-two individual tests were run on each alloy in the investigation described in the following pages. The data and curves presented herein represent an integration of all the tests to obtain the most accurate picture of the creep properties of these alloys. Neither of the two alloys was found to be embrittled by the combination of temperature and stress, as evaluated by room-temperature tensile and impact tests that were made following creep testing. These data indicate that no tendency toward embrittlement exists. It is recommended that 6300 lb. per sq. in. be used as a working stress for cold-drawn, annealed Monel at 900°F. and 13,200 lb. per sq. in. for cold-drawn, annealed Inconel at the same temperature. Table 8 lists recommended working stresses, based on 80 per cent of the stress to produce a minimum creep rate of 0.01 per cent per 1000 hr., for Monel and some steels. Equipment The equipment used for these tests consists of Colville creep-testing machines manufactured by the Tinius Olsen Testing Machine Co. The load is adjusted, depending on the stress level, to give an error in the stress of not more than ± 0.1 per cent. This is based on considerations of lever sensitivity and the stress used for the standard (A.S.T.M. Tentative Standard E22-38T) 0.505-in. diameter creep specimen having a 2-in. gauge length. The single-specimen furnaces are provided with primary and secondary windings, from

Jan 1, 1945

By Irwin Roman

NUMEROUS results and formulas have been published for analyzing seismic records, but most of them apply only to large-scale phenomena such as are encountered in studying earthquakes. In a few cases,1 formulas have been published for some of the simpler structures. In the present paper, an attempt will be made to analyze several types of struc-tures without using methods more advanced than those of a first course in calculus. In, tracing a disturbance through a medium, it is almost always possible to base the analysis on Fermat's Principle of Extreme Time, which states that waves of displacement travel between points in such a manner as to make the time of travel an extremum with respect to all neighboring paths. In the simpler cases, comprising most of those used in optics or geophysical prospecting, this time is a minimum and the principle is often referred to as the Principle of Least Time. Within a homogeneous medium, having a uniform speed of transmission of the disturbance in all directions and throughout the medium, the paths are straight and are refracted at the interfaces in accordance with the Snell law of refraction, which states that the ratio of the sine of the angle, made by the ray with the normal to the interface, to the speed of trans-mission is the same on both sides of the interface. Thus, in any medium composed of homogeneous sections, this same ratio has a constant value at all points. In particular, if all interfaces are horizontal, it is apparent that the angles of incidence are the angles made by the ray with the vertical direction. Furthermore, the incident ray, the refracted ray and the normal to the interface are all in the same plane at each refraction;

Jan 1, 1933

By E. W. Pehrson, J. W. Furness

THE five charts presented here- with are part of an original group prepared by the U. S. Bureau of Mines showing the international trade in the principal metals and metallic ores. Charts 011 anti- mony, chromite, copper, lead, manganese, mercury, nickel, tin, tungsten, and zinc were published in the February, 1936, issue of the Engineering and Mining Journal. Those shown here include bauxite, aluminum, iron ore, pig iron, and the platinum-group metals.

Jan 1, 1936

By F. V. Lenel

Resistance sintering under pressure is a method of hot pressing in which a powder compact is subjected to pressure and simultaneously heated by passing a low voltage high amperage current through it. Equipment for this process is described. Its basic characteristics such as resistance requirements for powders and compacts, temperature distribution in compacts, and gas reactions during resistance sintering are discussed. Examples of the sintering process in compacts made of a single metal or an alloy powder and in compacts made of mixtures of powders are presented. Potential commercial applications of the process are evaluated. THE usual sequence of operations in commercial powder metallurgy is to compact metal powders in a die at room temperature and sinter the compact subsequently without applying pressure while the compact is in the sintering furnaces. In hot pressing, on the other hand, the compacting and the sintering are combined. The loose powder, or in many cases a cold formed compact, is inserted into the die which is held at the hot pressing temperature, the compact is left in the die until it attains its temperature, and then pressure is applied and maintained for a given length of time. The die may be heated by surrounding it with a suitable furnace, by high frequency induction heating, or by passing current through the die. In hot pressing, compacts of high density and good mechanical properties can be produced in a relatively short time. One of the principal difficulties in hot pressing is the lack of suitable die materials which will have adequate strength at the hot pressing temperature. This difficulty can be overcome at least partially by heating only the material to be hot pressed without heating the die directly. This can be done by passing a low voltage high amperage current through the material and simultaneously subjecting it to pressure. Either loose powders or compacts can be hot pressed by this method in which the desired temperature is produced by the power dissipated in the metal powder. This method of hot pressing has been termed "electrical resistance sintering under pressure." The most significant differences between this operation and conventional hot pressing are: 1—The sintering times are very short, usually a fraction of a second and at most a few seconds. 2—The powder and die are initially cold. 3—Heat is generated within the powder itself and not conducted in from the die. 4— The pressure used is high. 5—Cooling following sintering is rapid, amounting to a quench. Resistance sintering of metal powders under pressure has been suggested repeatedly. In 1933, G. F. Taylor' proposed an apparatus which consisted of an insulating tube made of glass, or a ceramic filled with the powder to be pressed, and plungers above and below the powder. The powder was to be heated by passing an electric current through it and pressure was then applied. The apparatus was intended principally for hot pressing cemented carbides. Although the principle of resistance sintering under pressure is clearly shown in this patent, few details are given. A sintering period of a second or a fraction of a second, which is terminated by the operation of an inertia switch, is mentioned but no values for current density are mentioned. Low pressures, such as atmospheric pressure or a somewhat higher pressure exerted through a lever, are suggested. W. D. Jones' discussed electrical resistance sintering under pressure and proposed using resistance welding apparatus for this purpose. In a patent issued in 1944, G. D. Cremera described a method of electrical resistance sintering under pressure using resistance welding apparatus which was to be applied mostly to nonferrous metals such as copper, brass, bronze, and aluminum. Current densities of 400,000 amp per sq in., sintering times of 1 and 2 cycles of 60 cycle current, and pressures of 5 to 10 tsi are proposed. Cremer suggested using an

Jan 1, 1956

By E. S. Rowland, J. Welchner, R. H Marshall

This paper presents results on an extension into the realm of high-carbon steels of some work recently published1 on the effects of time at temperature, quenching temperature and prior structure on the hardenability of one 0.20 and four 0.40 per cent carbon alloy steels. It was shown at that time that unless the conditions of time, temperature and prior structure are substantially the same in performing the hardenability test as in conducting hardening of parts in production, the correlation of hardenability information with the hardness and properties of production parts is often not of satisfactory accuracy. The general effects of these variables on the austenitic grain size, distribution of excess carbides and critical cooling rate have been known for many years and one or more have been investigated by Shepherd,2,3 Davenport and Bain,4 Digges,5,6 Digges and Jordan,' Post and associates8 and Roberts and Mehl,9 to mention only a few. There has been no systematic investigation, however, into the quantitative variations produced on the hardenability of commercial high-carbon steels by changes in these factors of time, temperature and prior structure. Procedure A plain carbon hypereutectoid steel, S.A.E. 52100 and Graph-Mo, a molybdenum-bearing high-carbon steel containing some graphite, were chosen for this investigation. The chemical analyses of these electric-furnace steels are given in Table I. The procedure used was exactly that reported previously,' hence the details will not be repeated here. Normalized (165o°F.) and spheroidized prior structures were utilized on all steels with hot-rolled and quenched (I600°F. oil) prior conditions added for the plain carbon steel. The end-quench test developed by Jominy10 was sclected for use in this investigation and, with the noted exceptions, the American Society for Testing Materials standard procedure was followed. The effect of time at temperature was examined at intervals of o, 10 and 40 min. and 4 hr., and a few 16-hr. tests were run. Salt-bath heating of the specimens was employed to control and minimize the

Jan 1, 1944

By R. H. Marshall, J. Welchner, E. S. Rowland

This paper presents results on an extension into the realm of high-carbon steels of some work recently published1 on the effects of time at temperature, quenching temperature and prior structure on the hardenability of one 0.20 and four 0.40 per cent carbon alloy steels. It was shown at that time that unless the conditions of time, temperature and prior structure are substantially the same in performing the hardenability test as in conducting hardening of parts in production, the correlation of hardenability information with the hardness and properties of production parts is often not of satisfactory accuracy. The general effects of these variables on the austenitic grain size, distribution of excess carbides and critical cooling rate have been known for many years and one or more have been investigated by Shepherd,2,3 Davenport and Bain,4 Digges,5,6 Digges and Jordan,' Post and associates8 and Roberts and Mehl,9 to mention only a few. There has been no systematic investigation, however, into the quantitative variations produced on the hardenability of commercial high-carbon steels by changes in these factors of time, temperature and prior structure. Procedure A plain carbon hypereutectoid steel, S.A.E. 52100 and Graph-Mo, a molybdenum-bearing high-carbon steel containing some graphite, were chosen for this investigation. The chemical analyses of these electric-furnace steels are given in Table I. The procedure used was exactly that reported previously,' hence the details will not be repeated here. Normalized (165o°F.) and spheroidized prior structures were utilized on all steels with hot-rolled and quenched (I600°F. oil) prior conditions added for the plain carbon steel. The end-quench test developed by Jominy10 was sclected for use in this investigation and, with the noted exceptions, the American Society for Testing Materials standard procedure was followed. The effect of time at temperature was examined at intervals of o, 10 and 40 min. and 4 hr., and a few 16-hr. tests were run. Salt-bath heating of the specimens was employed to control and minimize the

Jan 1, 1944

By S. P. Rothwell

ABOUT thirty miles north of, the city of Belleville (which is situated on a branch of Lake Ontario), and in the township of Marmora, Ontario,: there is found a. belt of gold-bearing quartz veins, which present geological, mineralogical, and economic features of great interest to the profession. The district in which these veins are found is characterized as a rolling country, with low rounded bills of syenitic granite, overlain on the flanks of the hills by Silurian limestones, which lie in nearly horizontal beds, and in some places are so fine in texture as to afford lithographic stone of a fair quality. The gold-bearing veins run north and south through this belt of syenitic granite, and are quartz-filled true fissures, with micaccous or talcoid slates forming the walls of and horses in the veins. This

Jan 1, 1881

By M. Cohen, R. T. Howard

It has long been realized among metallurgists that a fast, reliable method for the quantitative determination of the percentage of microconstituents in an alloy would be of great benefit in studies of equilibrium and transformation in the solid state. For example, Polushkinl has shown that the compositions of two coexisting phases in a binary system at a given temperature may be calculated very simply with the aid of two alloys lying in the two-phase field if the relative amounts of the two phases in each alloy can be determined. Recently, Grange and Stewart2 have traced the course of the austenite-martensite reaction in a series of commercial steels by making visual estimates of the percentage of martensite formed as a function of cooling temperature. The correlation of mechanical properties with structure, a subject of wide-spread current interest, is likewise dependent upon quantitative microanaly-sis. Yet, there are very few investigations described in the metallurgical literature, wherein methods of quantitative microscopy are employed. Usually, the relative amounts of the microconstituents are estimated in a qualitative or semiquantita-tive way. The authors were faced with this problem some time ago in studying the kinetics of austenite decomposition. Several aspects of this research could not be treated satisfactorily by other quantitative tools, such as specific volume,' magnetic,6 dila-tometric, electrical resistance7 or x-ray measurements.a It became necessary to find an impersonal quantitative method that could be applied to microstructures. Fortunately, it was noted that geologists and petrographers had coped with quantitative microscopy to a considerable degree in their attempts to evaluate the mineral contents of rocks. A number of excellent articles were found on this subject, and since they appear to be unknown generally to many metallurgists, the first part of the present paper is concerned with a review of the literature in some detail. With this survey as a background, the authors have adapted the so-called methods of point-counting and lineal analysis to metallography, as described in the second part of the paper. Austenite-martensite structures were selected for illustration not only because they are important in many ways, but because such fine intermixtures are notoriously difficult to estimate visually. Literature Survey Perhaps the earliest work on quantitative microscopic analysis goes back to Delesse9 (1848) who proved mathemati-

Jan 1, 1948

By M. Cohen, R. T. Howard

It has long been realized among metallurgists that a fast, reliable method for the quantitative determination of the percentage of microconstituents in an alloy would be of great benefit in studies of equilibrium and transformation in the solid state. For example, Polushkinl has shown that the compositions of two coexisting phases in a binary system at a given temperature may be calculated very simply with the aid of two alloys lying in the two-phase field if the relative amounts of the two phases in each alloy can be determined. Recently, Grange and Stewart2 have traced the course of the austenite-martensite reaction in a series of commercial steels by making visual estimates of the percentage of martensite formed as a function of cooling temperature. The correlation of mechanical properties with structure, a subject of wide-spread current interest, is likewise dependent upon quantitative microanaly-sis. Yet, there are very few investigations described in the metallurgical literature, wherein methods of quantitative microscopy are employed. Usually, the relative amounts of the microconstituents are estimated in a qualitative or semiquantita-tive way. The authors were faced with this problem some time ago in studying the kinetics of austenite decomposition. Several aspects of this research could not be treated satisfactorily by other quantitative tools, such as specific volume,' magnetic,6 dila-tometric, electrical resistance7 or x-ray measurements.a It became necessary to find an impersonal quantitative method that could be applied to microstructures. Fortunately, it was noted that geologists and petrographers had coped with quantitative microscopy to a considerable degree in their attempts to evaluate the mineral contents of rocks. A number of excellent articles were found on this subject, and since they appear to be unknown generally to many metallurgists, the first part of the present paper is concerned with a review of the literature in some detail. With this survey as a background, the authors have adapted the so-called methods of point-counting and lineal analysis to metallography, as described in the second part of the paper. Austenite-martensite structures were selected for illustration not only because they are important in many ways, but because such fine intermixtures are notoriously difficult to estimate visually. Literature Survey Perhaps the earliest work on quantitative microscopic analysis goes back to Delesse9 (1848) who proved mathemati-

Jan 1, 1948

By Sharon Brady, Catherine O’Donoghue, John V. Beall, Paul C. Merritt

Between 1950 and 1965, more than 80% of all phosphate rock produced in the world each year was used as fertilizer, either directly applied to the soil or processed into mixed chemical fertilizers. Of the potassium salts produced, 95% followed suit. A variety of uses in industrial chemicals and consumer products absorbed the remaining percentage of each. Future trends in these two commodities will be dominated by what happens to the fertilizer market. Farming is much the same as mining the soil. Plants remove the minerals little by little. Phosphate and potash comprise two of the three primary nutrients removed in this way, the third being nitrogen. Phosphate stimulates early root formation and growth, whereas potash is a salt necessary to root strength.

Jan 10, 1966

By K. E. Brown, A. R. Hagedorn

A 1,500-ft experimental well was used to study the pressure gradients occurring during continuous, vertical, two-phase flow through 1-in., 1 1/4-in. and 1 1/3-in. nominal size tubing. The test well was equipped with two gas-lijt valves and four Mathak electronic pressure transmitters as well as with instruments to measure the liquid production rate, air injection rate, temperatures and surface pressures. Tests were conducted for widely varying liquid flow, rates, gas-liquid ratios and liquid viscosities. From these data, an accucrate pressure-depth traverse was construcred for each test in each of the three tubing sizes. From the results of these tests, correlations have beer] developed which allow the accurate prediction of flowing pressure gradients for a wide variety of tubing sizes, flow conditions, and liquid properties. Also. the correlations and equations which are developed satisfy the necessary condition that they reduce to the relationships approprate to single-phase flow when the flow rate of either the gas or the liqutid phase becomes zero. All the correlations involve only dimensionless groups. which is a condition usually Sought for in similarity analysis but not always achieved. The correlations developed in this study have been used to calculate pressure gradients for pipes of larger diameter than those upon which the correlations are based. Comparisons of these calcuclaed gradients with experimetally determined gradients for the same flow conditions obtained from the literature indicate that extrapolation to these larger pipe sizes is possible with a degree of accuracy sufficient for engineering calculations. The extent of this extrapolation can only he determined with additional data from larger pipe diameters. INTRODUCTION The accurate prediction of the pressure drop expected to occur during the multiphase flow of fluids in the flow string of a well is a wideiy recognized problem in the petroleum industry. The problem has been brought even more into prominence with the advent of tubingless or slim-hole completions which use small-diameter tubing. Many of the correlations which give reasonably accurale results in the lager tubing sizes are greatly in error when applied to small-diameter conduits. Small-diameter conduits are defined as 1 1/2-in. nominal size tubing or smaller. The study of the pressure gradients which occur during multiphase flow of fluids in pipes is exceedingly complex because of the large number of variables involved. Further difficulties relate to the possibility of numerous flow regimes of widely varying geometry and mechanism and the instabilities of the fluid interfaces involved. Consequently, a solution to the problem by the approach normally used in classical fluid dynamics based on the formulation and solution of the Navier-Stokes equation has not been forthcoming. This is primarily the result of the nonlincarities involved and the difficulty of adequately describing the boundary conditions. As a result of the foregoing, most investigators have chosen semi-empirical or purely empirical approaches in an efford to obtain a practical solution to the problem. Much of the previous work in this area was done in short-tube models in the laboratory. A number of problems arise, however, when attempts are made to extrapolate these laboratory results to oilfield conditions where a much longer tube is encountered. In those few studies where data taken in long tubes were utilized, the data covered only a limited range of the variables, and as a result inaccuracies are introduced when the correlations are extended outside the range of the original data. Also, as a consequence of the limited amount of data available for these studies, the effects of several important variables were overlooked. The problem of predicting the pressure drop which occurs in multiphase flow differs from that of single-phase flow in that another source of pressure loss is introduced, namely, those pressure losses arising from slippage between the phases. This slippage is a result of the difference between the integrated average linear velocities of the two phases, which in turn is due to the physical properties of the fluids involved. In contrast to single-phase flow. the pressure losses in multiphase flow do not always increase with a decrease in the size of the conduit or an increase in production rate. This is attributed to the presence of the gas phase which tends to slip by the liquid phase without actually contributing to its lift. Many investigators have attempted to correlate both the slippage losses and the friction losses by means of a single energy-loss factor analogous to the one used in the single-phase flow problem. In an approach of this type, hourever, many of the important variables, such as

Jan 1, 1966

By J. D. Rice, P. L. Wearden, W. L. Hensou

Solutions to the unsteady-state partial water-drive reservoir performance problem can be obtained through the use of analogue computers or high-speed electronic digital computers. The solutions that have previously been resolved for use on digital computers, however, demand a knowledge of the aquifer parameters. Generally, the analogue computers now in use do not require this knowledge. A solution is presented herein where the aquifer performance, expressed in terms of difference equations, is related to the reservoir performance as expressed by the modified Scbiltbuis material-balance equation. A numerical procedure for a medium-sized digital computer also is presented in which a solution to the set of equations defining the aquifer and reservoir performance is obtained and the aquifer parameters (permeability and sand thickness) are automatically optimized while simultaneously matching the known pressure behavior. Predicted pressure behavior can be calculated using rates from any assumed future production practice. The procedure provides an output format which presents the cumulative, incremental and average rate of natural water influx, the per cent gas-cap expansion, the calculated reservoir pressure, the measured reservoir pressure, and the difference between the measured and calculated pressures. Results of a test problem are presented in comparison with results obtained by the Bruce Analyzer, Ohio Oil Co. 's Pace General Purpose Analogue Computer, and Sun Oil Co.'s Single-Pool Electronic Reservoir Analyzer. These results indicate that unsteady-state reservoir perlormance for a single-pool system can be adequately simulated by a numerical method employing a digital computer and that the special-purpose analogue computer can be supplanted by this method. INTRODUCTION The numerical approach to the unsteady-state partial water-drive reservoir performance problem heretofore has been limited in that solutions have been resolved only for certain fixed parameters. Also, prior to the advent of high-speed electronic digital computers in the last few years, calculations were so tedious and time-consuming that they ordinarily were neglected, or some other means of obtaining the solutions were used. The analogue approach had been used for obtaining solutions to the transmission-of-heat problem and, consequently, means were developed for applying the electrical analogue to the unsteady-state reservoir performance problem. Bruce submitted a paper for AIME publication in Sept. 1942, in which he described an electronic device (now called the Bruce Analyzer) for analyzing the water-drive performance of any reservoir, based on either steady or unsteady-state flow characteristics. 1 Sun Oil Co. adopted the analogue approach in 1949 and now has two special-purpose high-speed electronic reservoir analyzers in use.2,3 Two main features of Sun's analyzers are (1) the high repetitive rate of reproducing the entire history of reservoir performance cyclically a number of times per second, and (2) the elimination of the necessity of knowing the properties of the associated aquifer. Since the advent of larger and faster digital computers, the possibility of incorporating this second feature into a numerical approach appeared feasible. Previous work has been done and material published covering the application of numerical methods to the behavior of the pressure with respect to time at any point in an associated aquifer? However, the aquifer parameters must be known from some source. The material presented in Ref. 4 has been used to a great degree in developing the numerical method described herein. DIFFERENTIAL EQUATION AND BOUNDARY CONDITIONS The problem of simulating the performance of a reservoir and the associated aquifer is to determine the characteristics of the aquifer such that the

No phase of the steel industry is more typical of its remark- able progress than is the evolution and development of the modern American blast furnace. The founding of the Institute in 1871 also marked the beginning of a new era in the pig-iron industry. The rapidly expanding westward development of the country, with its seemingly unlimited markets, gave rise to unprecedented demands for blast-furnace products. The manner in which the iron industry responded provides a fascinating chapter in the history of industrial development. Prior to this period, the iron industry of the United States, largely concentrated in the East, was based upon the consumption of local iron ores and local fuels, the latter predominately charcoal and anthracite. Small, isolated furnaces were located near scattered ore and fuel sources, and the completely integrated ironworks and steelworks were yet to be developed. In about 1860 exploitation of the newly discovered rich ore deposits in Michigan and the successful adaptation of blast furnaces to coke produced from coal of the great Pittsburgh seam in western Pennsylvania proved to be major factors in firmly establishing the general westward shift of the industry. But these were largely economic in character, and it was not until about 1870 that the aggressive, individualistic nature of the ironmaster asserted itself in no uncertain manner. No longer limited by relatively inadequate equipment and inferior raw materials, and spurred as well as encouraged by those who supplied capital for these new enterprises, furnacemen began to establish unheard of records in iron production. It is not surprising that Pittsburgh was the center of this new activity. Its tenor is best indicated by the following account :l

Jan 1, 1948

By E. V. Manlapig, David J. Spottiswood

In recent years great advances in the automatic control of flotation plants have been made, mainly due to the development of reliable sensing instruments to monitor process performance and the development of an adequate understanding of system responses to process disturbances. Some of the control strategies used in flotation plants which apply computer control are presented here. These schemes, which involve the control of collector; depressant, frother, and air and pulp level, are analyzed with respect to their control objectives, control variables, and the instrumentation involved. The knowledge gained in understanding these strategies may be applied in the dew and implementation of control system in other concentrators.

Jan 1, 1981

By Charles S. Barrett

THE experiments reported in this paper have been fruitful in disclosing the mechanism of the deformation of iron in compression. They have established the nature of "deformation bands," "etch bands," or "X-bands," that have been a recognized but little understood feature in the structure of cold-worked metals since the early days of metallography, and have shown the role of the bands in the development of preferred orientations by cold-working. The work has also shown the relation of the orientation of individual grains to the preferred orientation of the aggregate. Some of the methods previously used in the determination of the indices of slip planes and slip directions are shown to be untrustworthy in the presence of deformation bands. The conclusion is reached that many slip planes and slip directions must operate during each stage in the compression of a single crystal, and that theories failing to take account of this require revision. In conducting the experiments a method of compression has been used by which extreme reductions can easily be reached, even to the limit set by the metal's capacity to deform without fracture. The work is a portion of a research program on the plastic properties of iron and steel. It is being used as a foundation for studies of orientations resulting from recrystallization and is being extended to other metals and other types of deformation. PREVIOUS WORK The previous experiments are few and have given confusing results. Ono1 compressed a polycrystalline alpha-iron specimen between two flat plates of a testing machine and found that severe deformation oriented the crystals into a duplex preferred orientation, one set of crystallites having a cube diagonal of the body-centered cubic lattice parallel to the compression axis, and another set having a cube axis parallel to the compression axis. We shall speak of this structure as a. double fiber texture of the type [111] + [100]. Wever2 also made an X-ray determination of the texture

Jan 1, 1938