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By J. E. Hilliard

Isobaric sections of the eutectoid region of the iron-carbon phase diagram have been exgerimentally determined at 35, 50, and 65 kb. The phase boundaries were located by metallographic analysis of specimens quenched after equilibriatwn at known temperatures and pressures. With increasing pres -sure a pronounced decrease in the solubility of FesC in austenite was observed together with a depression of the eutectoid temperature. These two effects resulted in a shift of the eutectoid composition toward a lower carbon content; at 65 kb the eutectoid was at less than 0.2 wt pct C. These results are in qualitative agreement with thermodynamic calculations. It has also been shown by calculations that Fe3C in contact with saturated austenite will be stable with respect to both graphite and diamond formation at all pressures above -3.5 kb. 1 HE investigation described in this article was part of a more general study of the effect of high pressure on transformations in Fe-C alloys. Thermodynamic calculations and exploratory runs made in 1959 at the start of the program indicated an appreciable change with pressure in the phase equilibria of Fe-C alloys. However, the calculations were not considered reliable enought to provide the quantitative information required for the interpretation of the effect of pressure on the kinetics of transformations. An experimental investigation was therefore made to determine a series of isobaric sections of the eutectoid region of the phase diagram at pressures up to 65 kb. EXPERIMENTAL PROCEDURE Materials. Seven alloys with analyzed carbon contents of 0.10, 0.20, 0.38, 0.60, 0.77, 0.93, and 1.20 wt pct C were prepared from Ferrovac" iron and high-purity graphite induction melted in magnesia crucibles under argon. The ingots were hot worked and swaged down to 0.19-in.-diam rod which was then centerless ground to a final diameter of 0.125 in. Samples for chemical and spectrographic analyses were taken from each end of the rods. The prin- cipal impurities were found to be Ni, Al, Co, and Si which were present in amounts up to 0.03, 0.02, 0.01, and 0.01 wt pct, respectively. Specimens were prepared by slicing the ground rods into pills 0.06-in. thick which were silver plated to reduce decarburization during the equilibration. Silver was chosen for this purpose because of its very low solubility for carbon and its mutual immisicibility with iron. High-Pressure Apparatus. The high-pressure runs were carried out in the "Belt" apparatus.' As shown in Fig. 1, this consisted of a cylindrical cell compressed between two Carboloy punches loaded by a uniaxle press. Radial support to the cell was given by the "belt" which was a Carboloy die heavily prestressed by a series of steel binding rings. Laminated gaskets of lava and metal separated the punches from the inner surface of the "belt". A cross-section of the high-pressure cell is shown in Fig. 2. Two specimen pills were located inside a resistance heater of 0.20-in.-diam Nichrome tubing. The ends of the tube were sealed with alumina and lava pills tamped in place after the

Jan 1, 1963

By J. Wade Watkins, E. S. Mardock

The accurate evaluation of reservoir-performance characteristics in the secondary recovery of petroleum by water flooding requires use of a water tracer that may be injected into water-input wells and detected at oil-production wells to supplement data obtained from core analyses, wellhead tests, and subsurface measurements. Radioactive iodine has been used successfully as a water tracer in field tests to determine: (I) relative rates and patterns of flow of injected water between water-input and oil-production wells and (2) zones of excessive water entry into oil-production wells. Laboratory evaluations of potential water tracers, previous tracer studies, the value of using a radioactive tracer, general field procedures, and the use of surface and subsurface instruments for the detection of the emitted gamma radiation, are summarized. Data from the field tests are presented graphically and discussed in detail. It is concluded that the radioactive-tracer method, using radioactive iodine, may be used successfully to measure either the relative rates and patterns of flow or zones of excessive water entry into wells under conditions of comparatively rapid transit time between wells. INTRODUCTION Extensive use is made of data obtained from core analyses, wellhead tests, fluid characteristics, and subsurface measurements in evaluating the sweep efficiency of water injected into oil sands for the recovery of oil. Theoretical flow rates and patterns may be calculated from those data using radial-flow formulas, if it is assumed that the physical conditions in the productive formation are homogeneous. Unfortunately, homogeneous conditions rarely, if ever, exist in oil-productive formations. The use of a tracer that may be injected into an oil sand and detected quantitatively, or even qualitatively, at offsetting oil-production wells provides basic data that may be used in determining more accurately the subsurface rates and patterns of flow of injected water between wells than is possible by theoretical calculations based on assumed conditions. Consideration of the data obtained by using a water tracer assists in the application of remedial measures to water-input wells, such as plugging of channels, or selective plugging of highly permeable zones, thereby effecting a more uniform flood and a greater ultimate oil recovery. A water tracer should have the following characteristics: (1) low adsorption on solid reservoir material; (2) high solubility in water; (3) low or negligible solubility in crude petroleum; (4) a wide range of solubility of compounds that may be formed by chemical reactions with ions present in reservoir rocks or waters; (5) high detectability in low concentrations by portable apparatus; and (6) general availability at low cost. Additional desirable characteristics are that the tracer should be nonhazardous in nature under normal working conditions and quantitatively detectable in the well bore, as well as at the surface. Review of Previous Tracer Studies The need for a water tracer has been recognized for many years. As far back as 1906, Dole1 described the use of fluorescein in flow-rate studies made in France in 1901. In 1921, Ambrose" discussed in detail the use of organic and inorganic dyes, chlorides, nitrates, and other anions, lithium salts, and the Slichter electrical

Jan 1, 1955

By H. M. St. John

THE melting department is the heart of the foundry. From it clean metal flows to the molding floor, in the right quantity, at the right time and at a sufficiently low cost-or, if not, the foundry fails to thrive. Since it is our purpose here to discuss present-day melting practice in the foundry, it may be well at the start to emphasize the wide differences in foundries and the conditions under which they must operate in order to reach the goal stated in the first paragraph. In every foundry, large or small, jobbing or captive, the same factors must be dealt with but they are of varying consequence and must be dealt with in varying ways in different foundries. Particularly in the nonferrous industry, there is so wide a variation in the composition of alloys used and in the character of castings made that no one type of furnace, nor any one method of operation, can be expected to produce the best results at all times. The present discussion will not attempt to include all nonferrous metals. It is intended to cover only the copper-base alloys in which copper is the dominant element, most of which are commonly known as brass or bronze. The discussion is further limited to the melting of these copper-base alloys for use in sand-casting foundries. Die-casting plants, the brass-rolling mills and certain other metal industries have melting problems peculiar to those industries, which will not be considered here. The following considerations are elemental in all foundries and are listed in what is believed to be the relative order of their present-day importance: I. The melting department must meet the foundry's requirement for dean, fluid metal, of specified composition and purity, at a temperature suitable for the work the foundry has in hand. This is the prime consideration in any foundry, at any time, anywhere. 2. Working conditions surrounding the melting furnaces and attending their use must be good. 3. The cost of molten metal at the mold must be as low as possible. 4. The operating characteristics of the furnaces must be sufficiently flexible, to meet normal variations in foundry requirements. 5. The operation and maintenance of the melting equipment must not require more skill and experience than is available in the particular foundry in question. METAL QUALITY It is not a function of the melting furnace to refine or improve the quality of the metal but simply to melt it without impairing its quality. Good practice requires, therefore, that care must be taken to supply the melting department with metal of inherently good quality, assured by specification or otherwise, having all the properties necessary to produce the castings desired. An alloy contains a number of primary elements, which must be present in definite proportions if the castings made from it are to have the desired properties. If the castings are made to a customer's specification, this will state the range within which these principal elements (for example, copper, tin, lead and zinc) are permitted to vary.

Jan 1, 1946

By K. A. Johnson, F. H. Ellinger, C. C. Land

The Pu-In phase diagram has been determined by thevmal, filtvation, micrographic, and X-ray diffraction methods. This alloy system is characterized by 1) limited solubility of indium (-2 at. pet) in 6 and e plutonium, 2) one eutectic, and 3) fizte intermediate phases. Of the latter, PuIn and PuIn3 melt con-gruently, and Pu31n, Pu31n5, and the high-temperatuve 7 solid solution are formed peritectically. The n phase decomposes eutectoidally into Pu3In and PuIn at 865°C. Although the 6 phase can readily be retained to room temperature, it is not thermo-dynamically stable below 300°C. The Pu-In system has been investigated at Los Alamos as part of a study of the alloys of plutonium with the group 111-B elements. Constitutional studies of the Pu-A1 and Pu-Ga systems have been reported earlier.'9' To date, published information on the constitution of Pu-In alloys covers only the identification of the intermediate phases Pu3In and PuIn3.3,4 EXPERIMENTAL The alloys were prepared from five different lots of plutonium and three different lots of indium. The principal impurities in the plutonium differed from lot to lot within the following limits (in ppm): iron, 30 to 80; nickel, 30 to 60; aluminum, 15 to 30; silicon, 20 to 145: thorium, 50 to 300; carbon, 75 to 335; and oxygen, 20 to 135. Spectroanalysis of the indium showed that two of the lots were 99.9 wt pct pure, and the third was 99.98 wt pct pure. The alloys, in the form of about 5-g buttons, were prepared by arc melting in conventional equipment. The components for each alloy were weighed to the nearest 0.1 mg. In most instances the weight losses during melting were negligible; therefore confirmatory chemical analyses were usually not made. A few results are given in Table I. Density measurements of the arc-cast buttons were made by the liquid displacement of bromoben-zene. Heat treating was done in muffle furnaces controlled to +2°C. The alloy buttons were wrapped in tantalum foil before being enclosed in evacuated clear silica capsules. As a precaution against breakage, each capsule was in turn placed in a silica tube closed with a refractory wool plug prior to being charged into the furnace. For a moderately fast quench of the alloys, the outer protection tubes containing the capsules were plunged into cold water. Differential thermal analyses (DTA) in racuo were performed at heating and cooling rates of about 1.5°C per min. Tantalum crucibles having inverted thermocouple wells were used for most of the analyses. It was found micrographically, however, that the liquid alloys containing more than about 35 at. pct In reacted with the tantalum, resulting in contamination of the surface of the alloy. A search for a more satisfactory crucible material was not successful: tungsten and yttria behaved comparably to tantalum; thoria, vitrified magnesia, and vitrified alumina severely contaminated the alloys. So as to minimize the contamination by the crucible mater-

Jan 1, 1965

By R. W. Heckel

A method is described whereby the relationship of both the "at-pressure" powder compact density and the "zero-pressure" compact density to the applied pressure may be obtained from continuous measurements of punch movement during a single compaction operation. The rate of density increase with applied pressure for the metal powders is found to be proportional to the volume fraction of pores for pressures exceeding a lower limit which varies from 15,000 to 30,000 psi, depending on the powder. 1 HE compaction of powdered materials is carried out primarily to increase the density of the material. If the ultimate goal of the over-all process is the attainment of minimum porosity, compaction is responsible for most of the densification. For example, loose powdered metals have porosities of about 65 to 75 pct. Axial loading in a die or hydrostatic pressure may effectively reduce the porosity of most powders to 20 pct or lower with pressures of 50,000 psi and greater. The relationship between the density of a powder compact and the pressure needed to achieve that density is most commonly obtained by pressing several compacts, each at a different pressure. Measurement of the densities of the individual compacts when they are removed from the die then provides the density-pressure relationship. However, this method suffers from several disadvantages. Because a large number of compacts and pressing operations are required, it is inherently slow. Furthermore, since density measurements are made after the specimens are removed from the die, data obtained refer only to pressures greater than those necessary to form a coherent compact. The third disadvantage is the inability of this method to provide information about the compact density at the applied pressure in the die. Because the determination of density-pressure relationships has been a slow, tedious process, investigators have sought to express the compaction behavior of powders by other means. The general terms "comparability" and L'compressibility" have been used to rank powders qualitatively according to their compaction characteristics. To restore a quantitative nature to the subject and to prevent confusion, Schwarzkopf1 has proposed that compac-tibility be defined as the minimum pressure needed to produce a given green strength, while compressibility should be used to indicate the extent to which the density of a powder is increased by a given pressure. Probably the most widely used of the compaction parameters is the "compression ratio,'' which is generally defined as the ratio of the compact density obtained by pressing at a given pressure to the apparent density of the loose powder.2 However, the description of the compaction behavior of a powder by these parameters provides only limited information about the process because of their applicability to just one specific condition such as a given green strength or a given pressure. The method of obtaining density-pressure relationships which will be described in the present paper was designed to eliminate the shortcomings of the previous techniques while maintaining equivalent accuracy and precision. EXPERIMENTAL TECHNIQUES The general principle employed makes use of the fact that the linear movement of the punch during a

Jan 1, 1962

By Raymond D. Sloan

During 1944, substantial gains were recorded in practically every phase of the petroleum industry in Oklahoma. With the spotlight of activity focused on other states during the more recent years, the production momentum that was achieved in Oklahoma through the discovery and development of such outstanding pools as Oklahoma City, Fitts. and major pools in the Seminole area during the late 1920's and early 1930's was practically spent by the end of 1943. However, with much of the industry's exploratory efforts greatly reduced in Illinois, Indiana and Kentucky, the strong demand for Mid-Continent crude and the optimism created by some discoveries in the state toward the end of 1943, Oklahoma has again become the recipient of much activity and interest, with its 1944 drilling activity, production and refinery runs to stills registering substantial gains over the preceding year. Development and Exploration Since the discovery of the West Edmond pool in April of 1943, with the substquent drilling and development boom, the scene of exploratory activity has shifted from the central. south and east portions of the state to the general trend of the . Granite Ridge, where leasillg and wild-catting were greatly activated within a wide radius of this high subsurface feature. Leasing activity, however, jumped the confines of the Granite Ridge trend and extended into all of the northwestern counties in the state. Seismograph activity at once began following and keeping pace with this shift in the leasing and exploration locale, by the concentration of a large number of seismograph crews in the area. At one time during the year,35 crews were concentrated in Oklahoma, the majority being west of the Granite Ridge and extending into the northwestern counties. To illustrate the increase in geophysical work done in the state during the year, records indicate that 377 crew months were worked in 1944, which is a 21 per cent increase over the 311.5 crew months activated in 1943. With the discovery in 1943 of several encouraging prospects and the finding of West Edmond as an incentive, drilling operations increased some 54.3 per cent, for a total of 1986 completions during the year. This is compared with a figure of 1287 for wells drilled in 1943, an increase of 699 wells. The industry, with a total of 1064 oil producers, enjoyed a success percentage of 53.6 per cent. Gas wells completed were 223, while 699 dry holes were drilled. In 1943, completions included 587 oil wells, 127 gas wells, and 573 dry holes. The number of oil producers completed during the Year was almost double the numher of wells in 1943. Of the total drilling wells completed in the state, 350, or 17.6 per cent, were wildcat operations—an increase of 5.1 per cent over the 194.3 total of 333. The wildcat success percentage was 13.4 per cent, 47 successful wells being completed for an average initial potential of 160 bbl. In the state, 23 gas wells were completed with an average initial production of

Jan 1, 1945

By John F. Elliott, John R. Rawling

The rate of reduction of silica to silicon by carbon at 1550° to 1700°C in iron blast-furnace type slag-metal systems has been investigated. In the tower portion of the temperature range oxygen transport in the metal boundary layer at the slag-tal interface is probably rate limiting. A second step, which apparently involves a chemical process in the slag at the slag-metal interface, appears to be rate limiting when the oxygen-transport limitation is avoided. Above 1650°C rate control of the reduction by carbon probably is mixed between the two steps. INVESTIGATIONS1.2 into the equilibrium distribution of silicon between graphite-saturated slags and metals typical of iron blast-furnace practice show that, under the experimental conditions specified, the reduction of silica to silicon is relatively slow compared with the rates of other slag-metal reactions under similar conditions. For this reason, the reduction of silica in blast-furnace slag-metal systems was considered to be an interesting subject for further study. Investigations of the kinetics of the reaction3-5 suggest that several possible steps may be rate controlling, and that the rate-controlling step depends not only on the physical state of the systems but also on the configuration of the apparatus. The main objects of the investigation reported here were to sug- gest plausible reaction paths for the reduction of silica under the experimental conditions chosen and to determine the step or steps which control the rate of reduction of silica. EXPERIMENTAL Two types of experiments involving the reduction of silica from the slag were carried out. In the first, the only reducing agent present was carbon (graphite), for which the over-all reaction is (SiO2) +2C(gr) —Si + 2Co(g) [l] The second type was a graphite-saturated ferro-silicon-iron concentration cell. In it silica in the slag could be reduced either by carbon according to Eq. [I], or by a reaction of electrochemical nature in which silicon was oxidized at the ferrosilicon-slag interface and silica was reduced at the slag-iron interface without the formation of CO. The two types of experiment are described below. Reduction of Silica with Carbon as the Only Available Reducing Agent. The reduction of silica was accomplished by allowing a liquid lime-alumina-silica slag and graphite-saturated iron to react in an induction-heated graphite crucible. The crucible was 2.25 in. diameter and 5 in. deep; it was fitted with a graphite stirrer which penetrated through the slag and into the metal, Fig. 1. The slag and metal charges weighed 350 g each. Pure carbon monoxide at a pressure of 1 atm was maintained above the melt by passing the purified gas through the crucible at a rate of 0.5 liter per min. The gas did not stir either the slag or metal. Temperature measurements were made by sighting an optical pyrometer down the hollow stirrer rod into a 1/4-in. hole drilled in the stirrer blade. The crucible temperature was maintained within *15"C of the required value by manual control of the power supply to the

Jan 1, 1965

Charles H. Fulton, Rapid City, So. Dak. (communication to the Secretary*): Professor Lodge takes issue with Mr. Crawford and myself on results obtained by the scorification-method of assay on " zinc-box precipitates," which we published in a paper on the subject in the publication named below.' In our work we found that the normal seorification-method, employing only test-lead and a very little borax-glass as a flux, gave results on cyanide precipitates which mere invariably very low, loss having taken place by slag-absorption and volatilization, as repeated slag-assays failed to bring up results similar to those obtained by other methods. Professor Lodge anil his students made a large number of what he terms " scorification-assays," but which, I would like to point out, have claim to that name only in that they are made in a scorifier, for the charge consists of test-lead, a very considerable quantity of borax-glass (10 grams), at times also of litharge and even charcoal, so that the assays are in reality crucible assays. A scorification-slag proper is an oxide-slag to all intents and purposes, while the slags made by Professor Lodge are borates, certainly acid-slags. It has been our experience since our paper, The Assay of Cyanide Precipitates, was published, that the nature of the assay slag in the crucible assay has a great influence on the result. A " basic " or oxide-slag invariably causes high slag-losses, while an " acid " slag gives very fair results on material containing much zinc. This has also been the experience of a mellknown cyanide chemist with whom I have corresponded on the subject, who found that acid crucible-slags gave good results on zinciferous material, but that the scorification-method, as ordinarily employed, gave high slag-losses. I believe that if the conditions are such that the zinc can be

Jan 1, 1904

By William S. McAleer

Two major trends in the coal industry today focus attention on the need for heat-drying equipment of a simpler, more flexible and less expensive type than has been considered standard equipment for drying coal. These trends are: I. The tremendous growth in the use of mechanical equipment to load coal both in underground mining and strip mining, which necessitates efficient mechanical cleaning of the fine as well as the coarse coal and thus means a growing tonnage of washed fine coal? with its attendant moisture problems. 2. The growing consumer demand for the smaller sizes for use as domestic stoker coal, with increasingly rigid specifications covering size, ash, and moisture analyses. ACCEPTED PRACTICE In the past, when, for example, 4 in. too coal has been washed, there was little trouble in producing a washed product 4 to o with a satisfactory resultant moisture. The 4 to 3/8-in. could be taken from dewatering screens at a surface moisture ranging from 2.5 to 3.5 per cent, depending upon the size consist. The 3/8-in. to o coal was generally dewatered satisfactorily with centrifugal driers, to final surface moistures from 5.5 to 8 per cent, again depending upon size consist. The centrifugal type of drier has definitely proved itself to be the most economical type of machine to handle coal approximately 3/8 in. to o as recovered by dewatering screens or drainage elevators with 15 to 25 per cent surface moisture and turn out a product with moistures as stated above. Sometimes such moistures (5.5 to 8.0 per cent) in the product are satisfactory. If not, an ultimate moisture, lower than 3 per cent, is seldom required and the centrifugal drier removes 70 to 85 per cent of the total moisture to be removed. In certain districts there has been a growing tendency to circumvent the use of centrifugals or other types of driers, by dewatering over screens of the wedge wire type and wasting all the finer sizes. Sometimes all the minus 28-mesh has been wasted and often the size wasted has been as large as 1/8-in. By wasting these finer sizes, a lower moisture can be obtained in the finished product, but taking into account the cost of the tonnage so lost, plus the added cost of ultimately disposing of this wasted tonnage, often the cost will be greater than the cost of heat-drying in a modern plant, which makes possible the recovery of all the tonnage. Moreover, with the moisture standards for domestic stoker equipment even these wasteful approaches to its solution do not solve the problem and there remains only the alternative of heat-drying. HEAT-DRYING Until about four years ago, heat-drying of coal at the preparation plants was confined chiefly to drying the fine sizes (approximately 3/8 in. to 0). Occasional

Jan 1, 1941

By S. F. Urban, G. Derge

AT the time this investigation was initiated variations were observed in the quality of different heats of basic electric-furnace steels, although they had been made under purportedly similar conditions. This indicated that these variations were related to normally unobserved variations in the character of the bath, especially during the "refining" period. Although the slags used for this operation are commonly referred to as "reducing" slags, and are regarded as having a "deoxidizing" action on the bath, no reliable measurements of this action were available. It was decided, therefore, to study the behavior of oxygen in the metal for a large enough number of heats to learn its normal variations and to relate these variations to regularly observed conditions [f] operation. The most important general conclusion reached was that the time a heat is held under a reducing slag should be reduced to a minimum, which was about an hour and a half under the conditions studied. Beyond this time no observable beneficial effects are obtained from the reducing slags, insofar as oxygen and sulphur content of the bath are concerned. It is likely that added time may increase hydrogen content as well as heat costs. The oxygen content of the bath is never reduced below the amount in equilibrium with the carbon. Concurrently with this work, J. S. Marsh1 presented data that supplement and support many of the results of this paper. PROCEDURE The work was done in two different electric-furnace shops of the same plant. The selection of heats was made primarily with regard to the convenience of heat schedules. Companion slag and metal samples were taken just prior to slag-off and throughout the refining period for an initial set of 17 heats, and before slag-off and near tap for an additional 13 heats. Slag sampling presented no particular problem; a spoonful of slag was poured onto a metal plate and when sufficiently cool was sealed in an airtight container. Sampling the metal for oxygen presented a more complex problem. Because of the lack of previous experience in sampling electric-furnace baths, a number of methods were compared. Chilled Wedge Samples2 An unkilled metal sample is removed from tie furnace in a well-slagged carbometer spoon and poured immediately into a heavy copper mold designed to provide rapid freezing. Three different types of molds were used to determine the optimum for electric-furnace heats. The Big Wedge Mold (a) was a 4 by 4 by 4-in. split copper mold, yielding a wedge-shaped casting 1 in. wide, 1 ½ in. long, and ¼ in. maximum thickness, and was finally adopted as the most satisfactory design. The Long Wedge Mold (b) was a 2 by 2 by 5 ¼ -in. split copper mold, yielding a wedge-shaped casting 1 in. wide, 2 ¾ in. long, and ¼ in. maximum thickness. The Small Wedge Mold (c) was 2 by 2 by 4-in. split copper mold, yielding a wedge-shaped casting 1 in. wide, 1 ½ in. long, and ¼ in. maximum thickness.

Jan 1, 1947

By T. M. Geffen, F. F. Craig

Laboratory model flow tests have been made to simulate field conditions of partial pressure rnaintenance by dispersed gas drive on rocks having sandstone-type porosity. In this production method there is a significant saturation gradient between injection and production wells. A means of calculating relative permeability characteristics. from partial pressure rnaintenance flow tests has been developed. This method takes into account the saturation gradient. These kg/ko characteristics are identical to those for solution and external gas drives. This method of calculation, which has been proved experimentally, has limitations; however, it is valid for cases likely to be encountered in field prediction of partial pressure maintenance performance. The production performance of a hypothetical reservoir has been calculated for several different injection programs, involving both full and partial pressure maintenance. Results indicate that the maxinum oil recovery by these gas injection programs is obtained by full pressure mainte- nance at the original bubble point. Correspondingly lower oil recoveries are obtained by postponing gas injection and/or by reducing the degree of pressure maintenance. INTRODUCTION Dispersed gas injection is an important method of recovering additional oil beyond that obtainable by pressure depletion alone. The injected gas acts as a source of additional energy to displace oil from the rock formation as well as to retard oil shrinkage in the reservoir. In practice, gas injection is usually started after the reservoir pressure has fallen below the original bubble point. For various reasons sufficient gas is generally not injected to completely maintain the pressure in the reservoir. So, injecting gas at a declining reservoir pressure results in a combined external and solution gas drive. These two oil displacement processes are characterized by different gross saturation distributions in the reservoir. The external gas drive, like all frontal drive processes, inherently results in an oil saturation which increases from the injection wells to the producing wells. In the solution gas drive there is essentially a uniform oil saturation throughout the reservoir, provided the field is being depleted uniformly. It has been customary to predict oil recovery performance under partial pressure maintenance by a method which does not take into account the saturation gradient1. It has been shown2 that neglecting the presence of a saturation gradient can cause considerable error. It is the purpose of this paper to develop and present an improved method of predicting partial pressure maintenance performance of reservoirs including, where necessary. the effects of well arrangement. From the laboratory standpoint, this problem involves the measurement of the basic flow behavior (relative permeability characteristics) under partial pressure maintenance conditions. Recent research- as shown that for rocks having sandstone-type porosity, the relative permeability characteristics are identical for solution gas drive and complete pressure maintenance external gas drives. Since both solution and external drives have the same basic flow behavior, it was speculated that partial pressure maintenance, being a combination of the two, would also

Jan 1, 1957

By M. H. Cullender

The performance characteristics 01 gas wells producing from formations which fail to stabilize within a relatively short period of time are obscured by the interrelation of the coefficient (C) and the slope "n" of the conventional back-pressure curve q = C(P2 f- p2s)n An empirical method is presented whereby the characteristic or true slope (11) of the back-pressure curve may be determined for a particular gas well. For those gas wells which do not stabilize within a relatively short period of time, the coefficient (C) is considered as a variable with respect to time and as a constant only with respect to a specific time. Thus, the back-presrure performance of such a well is presented as a series of parallel curve5, each curve representing the performance of the well at the end of a given time interval. Through use of the method presented, a simple presture gradient is developed and maintained within the drainage area around a producing gas well during the test period in order that the variation of the coefficient (C) with respect to time does not obscure the true value of the lope. INTRODUCTION The back-pressure method of testing gas wells as set forth by Schellhardt and Rawlins1 is dependent upon the requirement that a series of flow rates and corresponding pressure data be obtained under stabilized conditions. These data arc then plotted on logarithmic coordinates of flow rate (Q) vs difference in squared pressures (P2f — P2s) in order to determine the constants (C) and (n) for Equation 1. With respect to this method of presenting the performance characteristics of a gas well, it should be pointed out that although Equation 1 is an empirical relationship, the form of the equation was justified to a considerable extent by an independent development by Muskat and Botset.2 This development was theoretical in nature; however, certain assumptions with respect to the type of flow existing (viscous vs non-viscous) were madc which may or may not be correct. As the use of the method presented by Schellhardt and Rawlins spread through the industry, it became evident that the method of testing was applicable for those wells which approached stabilized prbducing conditions within a relatively short period of time. Performance characteristics could not be determined by this method, however, for wells which approached stabilized protlucing conditions slowly over a considerable period of time. This characteristic of "slow stabilization" has generally been associated with gas wells producing frorn reservoirs of low permeability. As the demand for natural gas continued to grow through the years, a great number of wells were completed in reservoirs of low permeability which exhibited "slow stabiliz:~tion" characteristics. Consequently, the problem of determining the true performancc characteristics of these wells became more apparent. It is with this problem in mind that the isochronal performance method of determining the flow characteristics of gas wells is presented.

Jan 1, 1956

By Orville R. Lyons, A. C. Richardson

During the past few years there has been a growing demand by coal operators for detailed information about the performance characteristics of the various dryers now being manufactured, preferably in such a form that the information could be used to determine the type of dryer best suited to a particular drying problem. A few operators have been desirous of going even further, because they are of the opinion that present-day dryers are not properly designed and that fundamental studies of dryer design should be undertaken. This growing demand for a method of dryer evaluation and the indicated need for fundamental research resulted in the sponsorship by Bituminous Coal Research, Inc. of a project at Battelle Memorial Institute to investigate the thermal drying of coal. In investigating this problem, the most feasible method of attack appeared to be a survey of active operations to determine the present status of the thermal drying of coal. Data were obtained, usually by actual plant tests with the cooperation of the various preparation engineers and their staffs, for 9 screen-type dryers, 8 rotary-type dryers, 3 continuous-pallet-type dryers, 2 flash-type dryers, I tray-type dryer, and I cascade-type dryer. The testing program provided: (I) data for 24 coal-drying operations, (2) information about the inherent characteristics of the coals dried, (3) information about the previous treatment that the coal had received, and (4) information about operating costs. The data obtained through the dryer survey and relationships determined from the data make it evident that all of the types of dryers included in the survey can be operated with the same degree of effectiveness if each type of dryer is used to dry the sizes of coal for which it is best suited. It should be noted that it is usually undesirable and often impossible to dry different sizes of coal in one type of dryer. By use of the data in the report, any prospective dryer user, having determined the surface moisture percentage and screen-size analysis of the coal to be dried, the tons of water to be removed per hour, and the final surface moisture percentage desired, should be able to determine with a fair degree of accuracy: (I) the difficulty of the drying problem, (2) the approximate cost of drying, (3) the required dryer inlet gas temperature and volume and exhaust gas temperature and volume, (4) the type of dryer to use, and (5) the size of dryer required. The method of testing the dryers and determining the difficulty of drying can be used by operators already having dryers to check the performance of their particular dryer and determine whether they are operating effectively. Considerably more information was obtained from the survey of thermal drying than was anticipated when the survey was first considered. However, a great deal of work still remains to be done in the field

Jan 1, 1949

By Orville R. Lyons, A. C. Richardson

DURING the past few years there has been a growing demand by coal operators for detailed information about the performance characteristics of the various dryers now being manufactured, preferably in such a form that the information could be used to determine the type of dryer best suited to a particular drying problem. A few operators have been desirous of going even further, because they are of the opinion that present-day dryers are not properly designed and that fundamental studies of dryer design should be undertaken. This growing demand for a method of dryer evaluation and the indicated need for fundamental research resulted in the sponsorship by Bituminous Coal Research, Inc. of a project at Battelle Memorial Institute to investigate the thermal drying of coal. In investigating this problem, the most feasible method of attack appeared to be a survey of active operations to determine the present status of the thermal drying of coal. Data were obtained, usually by actual plant tests with the cooperation of the various preparation engineers and their staffs, for Q screen-type dryers, 8 rotary- type dryers, 3 continuous-pallet-type dryers, 2 flash-type dryers, I tray-type dryer, and I cascade-type dryer. The testing program provided: (I) data for 24 coal- drying operations, (2) information about dried, (3) information about the previous treatment that the coal had received, and (4) information about operating costs. The data obtained through the dryer survey and relationships determined from the data make it evident that all of the types of dryers included in the survey can be operated with the same degree of effectiveness if each type of dryer is used to dry the sizes of coal for which it is best suited. It should be noted that it is usually undesirable and often impossible to dry different sizes of coal in one type of dryer. By use of the data in the report, any prospective dryer user, having determined the surface moisture percentage and screen- size analysis of the coal to be dried, the tons of water to be removed per hour, and the final surface moisture percentage desired, should be able to determine with a fair degree of accuracy: (I) the difficulty of the drying problem, (2) the approximate cost of drying, (3) the required dryer inlet gas temperature and volume and exhaust gas temperature and volume, (4) the type of dryer to use, and (5) the size of dryer required. The method of testing the dryers and determining the difficulty of drying can be used by operators already having dryers to check the performance of their particular dryer and determine whether they are operating effectively. Considerably more information was obtained from the survey of thermal drying than was anticipated when the survey was first considered. However, a great deal of work still remains to be done in the field

Jan 1, 1948

By A. R. Krause, C. Laird

In order to establish whether or not there is a real temperature effect in fatigue (independent of environment) , poly crystalline copper and Cu- 7.9 A1 alloy have been cycled at 298° and 7° K in vacuo and the fatigue lives compared with those in air and in liquid nitrogen. The lives of both copper and the alloy were found to be highly temperature-dependent in the absence of environment. This result casts serious doubt on the validity of the cell structure hypothesis for stage I crack propagation as presently formulated, because it predicts that there should be no such tempevnture dependence. On the other hand, the plastic blunling process is consistent with the result. Effects of environment aside, the homogenization of slip which accompanies testing at low temperature, and at low strains, seems to be the main cause for increased fatigue life. At high strain amplitudes, the fatigue lives of wavy slip materials, typically copper, are independent of temperature.' It is well-known, however, that low-strain lives greatly as as the temperature of testing is decreased. By contrast, the lives of planar slip materials, such as Cu-7.9 pct A1 alloy, increase to an even greater extent with decreasing temperature throughout both the high and low strain ranges.1'2'5 The mechanism of this temperature effect is associated with the earliest stages of fatigue failure,'" crack nucleation, and stage I growth,"' which is slow propagation along slip bands to the depth of a few grain diameters. Such life behavior has been interpreted on at least two different bases. On the one hand, those interested in the temperature effect at high strain amplitudes1 believe that stage I growth occurs by the plastic blunting process of crack propagation.7'9 They explain the effect in planar slip materials by the homogenization of slip* which accompanies fatigue testing at low temper- atures and serves both to delay crack nucleation and to decrease the rate of stage I propagation. On the other hand, Holt and Backofen,2 who have studied the effect in low strain fatigue, believe that stage I growth can be interpreted by a cell structure hypothesis.10-12 They have challenged2 the conclusion that there is a real temperature effect in this regime of fatigue testing and have interpreted the increased fatigue lives almost entirely in terms of the "environmental-protective'' effect of the liquid nitrogen and helium baths used to obtain low temperatures. This interpretation by Holt and Backofen2 may offer a means of discriminating between these two mechanisms as currently formulated and used to explain stage I growth. On the basis of the plastic blunting process applied to stage I crack propagation,7* the low strain fatigue lives of both wavy and planar slip materials should be increased with decreasing temperature. This follows because both materials show increased slip homogenization in this strain regime."13 Consequently, crack nucleation in intensified bands will be delayed and the linking of such small cracks into larger stage I cracks will be difficult. In addition, the blunting process required to lengthen a stage I crack from the order of 2 to 10 (where the strain concentration of the crack begins to overcome the slip homogenization property of the material) will also be retarded. These delays will give rise to longer lives in both kinds of material. In contrast to the blunting hypothesis, no temperature dependence has been predicted on the basis of the cell structure hypothesis, because it is well-known that materials cycled at low temperature show no differences in type of dislocation structure for a given strain amplitude.18"20 If the lives of wavy and planar slip materials do show a temperature dependence when the environment is eliminated as a variable, then it is questionable whether cell structures per se have a fundamental role in fatigue fracture. Accordingly, specimens of copper and Cu-7.9 wt pct A1 have been cycled at 298° and 77°K in vacuo and the fatigue lives compared with those in air and in liquid nitrogen, in order to establish whether or not there is a real temperature effect in low strain fatigue. Since it is difficult to measure the strains in specimens when cycled in vacuo, S-N curves have been used as the basis of comparison. In studying the influence of temperature on fatigue life in ordinary environment, Holt and Backofen2 used the superior basis of E-N curves. However, they also published S-N curves and thus established the relationship between E-N and S-N curves. This relationship is used to support the S-N comparison reported in the present investigation. EXPERIMENTAL Materials. The copper employed in this investigation was of 99.99 pct purity and the cu-7.9 pct A1 was prepared from metals of the same purity. The stock, of 3 in. initial diam, was reduced in size by rolling

Jan 1, 1969

By S. R. Goodman, Hsun Hu

A detailed study of texture developmenf in poly crystalline copper atzd 70-30 brass has been completed. Textural changes as a function of deformation are shoum by pole jigmres and by intensity measurements oF- various rejlectiotzs from the rolling plane and the rolling direction. These examinations were accompanied by measurements of stacking fault frequency, hardness changes, and microstructure. Some of the results were briefly presented earlier. Additional results reported here are consistent with the idea that deformation faulting or slip by partial dislocations is of primary importance in the formation of deformation textures in fcc metals. lo examine the idea that deformation faulting is of primary importance in determining whether the texture is the copper type or the brass type an extensive study of the development of polycrystalline textures in copper and 70-30 brass was initiated. Besides the determination of complete pole figures, the intensities of the various reflections from both the rolling plane and the plane perpendicular to the rolling direction, the peak shifts due to deformation stacking faults, and the hardness of the rolled specimens were examined at various reductions from 10 to 99 or 99.5 pct. Mi-crostructures were examined by transmission electron microscopy. Some of the results were briefly presented in an earlier publication.' Since then, additional information has been obtained. This is given in the present paper. EXPERIMENTAL PROCEDURE Material and Specimen Preparation. The material used was a commercial electrolytic copper bar 1i in. wide and 2 in. thick and a 70-30 brass bar la in. wide and 1i in. thick. Chemical analysis indicated a purity of 99.97 pct for the copper, with 0.025 pct 0 as the major impurity. The 70-30 brass was of higher purity with 0.0016 pct 0 as the major impurity. Extreme care was taken in the preparation of the starting material to insure uniformly fine grains with a nearly random initial texture. The two bars were first cold-forged and then annealed to eliminate any original texture. The grains were then refined by several cold rolling (approx 30 pct reduction) and annealing treatments. The + -hr anneals were carried out in a salt bath at 390" to 440°C for copper and at 490°C for brass. The resulting penultimate grain size was 0.06 mm for copper and 0.03 mm for brass, and both showed very little preferred orientation. The number of prior cold rolling and annealing cycles was such that the final thickness after various final reductions of 10 to 95 (for brass) or 99 (for copper) pct was the same (0.020 in.). These annealed strips were rolled in two directions by reversing end for end between passes according to the following schedule: 0.006 in. per pass to 0.100 in., 0.003 in. per pass to 0.050 in., 0.002 in. per pass to 0.025 in., 0.001 in. per pass to 0.020 in. Texture Determination. The development of rolling textures was studied by examining complete pole figures determined from the (111) reflection. Specimens thinned from one face of the strip to half thickness (0.010 in.) were used to obtain the central portion of the pole figures, while specimens thinned from both faces to 0.003 in. were used to obtain the peripheral portion. The reflection and transmission techniques have been described previously. In addition to X-rav pole figures, texture development was also studied b; examining the intensity variation of the (Ill), (200), (2201, (311), (331), (420), and (442) reflections from the rolling plane and from the plane normal to the rolling direction, as a function of deformation. The same specimens used for the central portion of the pole figures were used for the intensity measurements of the various reflections from the rolling plane. For intensity measurements from the plane normal to the rolling direction, composite specimens were prepared by mounting sections cut parallel to the transverse direction of the strip. An epoxy resin was used to bond these sections together, and the entire composite was then mounted in a cold-setting resin to facilitate subsequent polishing and etching to remove distorted metal at the cut. The intensities were expressed in units of the integrated intensities measured from an annealed copper specimen having almost no preferred orientation. Stacking Fault Frequency Determination. Following the analysis of Warren: the stacking fault frequency, a, was determined from the change in the peak separation (A%) of two neighboring reflections of a deformed specimen, as compared with the normal peak separations of a fully annealed specimen. To obtain sufficient intensities for the second-order reflections, (222) and (400), composite specimens were prepared from parallel sections cut from the strip at 30 deg to the rolling direction for copper and 25 deg for the brass.* From texture data, these sections are known to contain a large population of both (111) and (200) planes. Since residual stresses can also cause X-ray line shifts (the direction of line shifts depends upon the sign of the stress), the use of composite specimens consisting of sectioned planes should help compensate for these effects as the residual stresses change sign from the surface to the central section of a rolled strip. Since the amount of peak shift is almost un-measurable in brass rolled 15 pct and in copper rolled

Jan 1, 1969

By K. P. Mukherjee, K. P. Gupta, J. Bandyopadhyaya

Even though a lot of work has been done in the past to establish phase equilibrium in the Cu-Si system a re cent investigation casts some doubt about the existence and crystal structure of some of the phases that form in the composition range of 15 to 25 at. pct Si in Cu. The present investigation was carried out using high temperature X-ray diffraction technique along with other standard techniques to study the phases in this composition range. The high temperature 6 phase appears to be tetragonal with parameters a,, = 8.815A, c, = 7.903A, and co/ao = 0.896. The reported bcc E phase exists at room temperature and at least up to 780°C and appears to undergo a transformation near 600°C. The phase appears to be cubic but not of the bcc type. The ? phase appears to undergo a transformation, as has been indicated by earlier investigators, and the low temperature form of .? phase is tetragonal with parameters a, = 7.267A, co = 7.8924, and co/ao = 1.086. THE Cu-Si binary system has been investigated by several investigators1" and several intermediate phases,?,e,?' at lower temperatures and ?,ß,0,e, and ? at higher temperatures, were observed between terminal solid solutions of copper and silicon. Even though the existence of the e phase and the transformation in the ? phase were reported in many early works, in a recent study of this system Nowotny and Bittner6 doubted the existence of the e phase and phase at 550°C. Among the high temperature phases, the 6 phase was reported to have a complex cubic structure with parameter a, = 8.805A.7 Nowotny and Bittner, however, suggested that the structure of the 6 phase might be of CsCl type. In order to check these contradictory reports the present study was taken up to investigate the Cu-Si binary system in the composition range of 17 to 25 at. pct Si. EXPERIMENTAL PROCEDURE Weighed amounts of copper (99.99 pct) and silicon (99.9 pct) were induction melted in recrystallized alumina crucibles under argon gas atmosphere. The alloys containing 17, 18, 20, 21, 21.2, 22, and 24 at. pct Si were annealed in evacuated and sealed quartz capsules at 700°C for 3 days and subsequently water quenched. Other than this annealing, the 21.2 at. pct Si and 24 at. pct Si alloys were annealed at 550°C for 10 days, the 17 at. pct Si alloy was annealed at 750°C for 3 days, and the 22 and 24 at. pct Si alloys were annealed at 780°C for 2 days. All annealing temperatures were controlled to within *l°C. Alloys after quenching were subjected to metallographic and X-ray diffraction investigation. A solution containing 5 g FeC13 + 10 cc HCl + 120 cc H2O diluted with six times its volume with water was used as etching reagent. A 114.6 mm diam Debye Scherrer camera was used for obtaining diffraction patterns. The 17, 21.2, and 24 at. pct Si alloys were subjected to high temperature diffractometry using a Tempress Research High temperature attachment and a GEXRD VI diffractometer. For the 6 phase (17 at. pct Si alloy) powder specimen from a 750°C annealed alloy was reheated to 750°C in the high temperature attachment for 1½ hr before taking a diffraction trace. A 550°C annealed and slowly cooled phase (24 at. pct Si) alloy was first reheated to 550°C. a diffraction trace was made after annealing it for 2 hr, and subsequently it was heated to 716OC and kept at this temperature for 2 hr before taking a diffraction trace. For the e phase (21.2 at. pct Si alloy) a 550°C annealed and slowly cooled specimen was heated first to 425°C and annealed at this temperature for 2 hr before taking a diffraction trace. Subsequently, the specimen temperature was raised to 495", 540°, 603", 635", 682", 720°, and 748°C and homogenized at each temperature for 1 hr before taking diffraction traces. The powder specimen temperature was controlled to within +2oC at each temperature and argon gas, purified by passing it at slow rate through a fused CaC12 column, hot (800°C) copper and titanium chips and finally through a P2O5 column, was used to prevent oxidation of the powder. For all X-ray work copper-radiations at 25 kv, 15 ma (for Debye Scherrer technique), and 40 kv, 20 ma (for diffractometer tech-nique) were used. RESULTS AND DISCUSSION At 700°C the alloys containing 17 to 21 at. pct Si showed two phases while the 21.2 at. pct Si alloy was found to be single phase. The X-ray diffraction patterns of the two-phase alloys were consistent with the phase (ßP-Mn type structure) and the phase (21.2 at. pct Si) patterns. The diffraction patterns of the 17 at. pct Si alloy quenched from 750" and 700°C were identical. According to the accepted Cu-Si phase dia-gram4,5,10 the 17 at. pct Si alloy at 750°C should be in the (k + 6) two-phase region and very close to the -phase boundary. The identical patterns possibly resulted from the decomposition of the 6 phase on

Jan 1, 1970

By Thomas M. Drown

IN the course of some experiments on the analysis of pig iron, I heated, in a platinum crucible, some borings of a graphitic pig iron with sodium carbonate. When the crucible was at a full red heat and the carbonate was thoroughly fused, I noticed a lively ebullition of the mass, and an escape of gas, which burned on the surface. On investigation this gas proved to be carbonic oxide, and on examining the borings in the bottom of the crucible after an hour or two, they were found to be perfectly malleable, although unchanged in general form and appearance. Analysis showed that the carbon was completely removed. I then repeated the experiment, to ascertain whether the silicon and phosphorus were affected, and found that these elements too were largely removed, and could be found in the fused mass as alkaline silicates and phosphates. In order to ascertain whether the removal of the silicon and phosphorus was merely a surface action or whether the reaction really extended into the mass of the iron, I tried the following experiments : A number of bars of pig iron were cast about one foot long and planed down-accurately to one inch section. These were immersed in a large wrought-iron pot full of molten sodium carbonate made by fusing the commercial bicarbonate of soda. Through the kindness of Mr. Frank Firmstone, Superintendent of the Glendon Iron Works, Easton, I was enabled to keep this pot at a reasonably constant high temperature for a long time in one of the hot-blast ovens. One of the bars was removed from the pot every twenty-four or forty-eight hours, according to the rapidity of the action, and after cooling was broken and the fracture examined. The change from pig iron to malleable iron was progressively inwards and always sharp and easily recognized, the rate of progression being in a decreasing ratio with the time. The temperature of the oven had evidently

Jan 1, 1879

By Thomas M. Drown

In the course of some experiments on the analysis of pig iron, I heated, in a platinum crucible, some borings of a graphitic pig iron with sodium carbonate. When the crucible was at a full red heat and the carbonate was thoroughly fused, I noticed a lively ebullition of the mass, and an escape of gas, which burned on the surface. On investigation this gas proved to be carbonic oxide, and on examining the borings in the bottom of the crucible after an hour or two, they were found to be perfectly malleable, although unchanged in general form and appearance. Analysis showed that the carbon was completely removed. I then repeated the experiment, to ascertain whether the silicon and phosphorus were affected, and found that these elements too were largely removed, and could be .found in the fused mass as alkaline silicates and phosphates. In order to ascertain whether the removal of the silicon and phosphorus was merely a surface action or whether the reaction really extended into the mass of the iron, I tried the following experiments : A number of bars of pig iron were cast about one foot long and planed down 'accurately to one inch section. These were immersed in a large wrought-iron pot full of molteu sodium carbonate made by fusiug the commercial bicarbonate of soda. Through the kindness of Mr. Frank Firmstone, Superintendent of the Glendon Iron Works, Easton, I was enabled to keep this pot at a reasonably constant high temperature for a long time in one of the hot-blast ovens. One of the bars was removed from the pot every twenty-four or forty-eight hours, according to the rapidity of the action, and after cooling mas broken and the fracture examined. The change from pig iron to malleable iron was progressively inwards and always sharp and easily recognized, the rate of progression being in a decreasing ratio with the time. The temperature of the oven had evidently

Jan 1, 1879

By John V. Beall

Homeland of the Republic of China, the island of Taiwan looks on the map like a seal, muzzle pointed south, resting complacently on the emerald waters of the China Sea. Any notion of placidness is quickly dispelled by going to that country where the visitor gains the impression of almost violent busyness in tearing up streets, pushing up buildings and tilling the fields. Driving from the airport downtown to Taipei, the capital city, one sees roads, streets and thorough-fares which seethe with bizarre traffic. From water buffaloes to buses, transportation takes every conceivable shape, size and color in between. The load being transported need not conform in any way to the capabilities of the vehicle. Twenty- foot lengths of pipe may be trans- ported on a bicycle. A family of five may go to town on a motor- cycle. Impossible? Count them. The streets and buildings of the city appear unrestrained, or without margins. Shops do not end at the doorway but overflow with a variety of goods onto the sidewalks and into the streets where the marginal traffic, on foot or on wheels, intertwines unconcernedly with the flotsam from the shops. Signs, dry goods, hardware and the continuous hubbub make the view colorful, lighthearted and fascinating. The island is 230 miles long by 75 miles wide with a central mountain spine. To the east, the mountains descend steeply to the ocean whereas to the west, beyond the foothills, there is a broad coastal plain. Only about 25% of the land is suitable for cultivation but the tropical climate permits several harvests a year. At the same time the mountains, which are high enough to sometimes have snow, offer an agreeable change of temperature. In this setting, society has created an economy that is growing at such a rate on all fronts that it would seem to be fairly bursting at the seams.

Jan 9, 1969