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By Elmars Ence, Harold Margolin

The partial isothermal section of the Ti-Cu-Zr system at 750°C has been studied. The crystal structure of Ti2Cu has been detevnlined as tetragonal and when expressed as face-centered tetragonal, a = 4.164, c = 3.611 A, and c/a = 0.867. TITANIUM systems in which ß-titanium decomposes eutectoidally into a and a compound rather readily are known as active eutectoid systems. Recently in active eutectoid alloys based on the Ti-Cu system, and containing additionally A1 and Zr, it has been found that zirconium may produce both moderate weakening and marked strengthening at elevated temperatures.' In order to obtain some insight into the behavior of zirconium, an attempt was made to determine whether compounds of the type Tix Zr and TixZryCu exist. Only results of the Ti-Zr-Cu studies are reported here since data on Ti-Zr alloys will be presented in a separate publication. EXPERIMENTAL PROCEDURE Alloys were nonconsumably arc melted in argon atmosphere as 15-g buttons, prepared from materials of the following purities: Bureau of Mines electrolytic Ti — Bhn 63 OFHC copper Reactor Grade Zirconium Bhn .C 150 Prior to alloy preparation the electrolytic titanium was premelted to avoid excessive spattering of the charges during melting. The weight losses during melting did not exceed 1 pct of the total weight of the charge. The alloys prepared are listed in Table I together with analyzed compositions. in cases where they were determined. Specimens for heat treatment were wrapped in molybdenum sheet, annealed in argon-filled quartz capsules, and quenched by breaking the capsules under iced brine. About 1 to 2 sec are required to remove the capsule from the furnace, drop it into the iced brine and break it. Because of the insulation effect of the quartz, this delay in quenching should not produce a large drop in temperature. In many instances, no difference or little difference has been detected between the same specimen quartz capsule quenched or directly quenched in vacuum by an impinging stream of water.' Ti-Cu-Zr alloys were homogenized for 48 hr at 825°C prior to annealing at 750°C. Annealing for 5 days at 750°C produced the same results as 11 days at temperature and it was therefore assumed that 5 days was sufficient to establish equilibrium. Titanium-copper alloys were homogenized for 40 hr at 900°C prior to heat treatment for 6 days at 750°C. Specimens for metallographic examination were electropolished and etched with the following solution:

Jan 1, 1962

A. M. Strong, Bishop, Cal. (communication to the Secretary*) :—The paper of Mr. Eeyes gives us the most complete account of the geology of the borax-deposits in the Death Valley region that has yet been published, and is a valuable addition to the geological literature of a very interesting though little-known territory. During the past ten years I have been over much of the northern part of the country described by Mr. Eeyes and the region immediately north of it.

Jan 1, 1910

By J. D. Alexander, W. L. Martin, J. N. Dew

This paper presents data obtained using a flood-pot technique to determine the fuel available and the corresponding theoretical air requirements for in situ combustion of crude oils. Since the technique is relatively quick and easy, it is a practical and convenient tool for evaluating reservoirs as fireflood prospects. It is also a research tool which facilitates systematic study of the variables affecting fuel availability and corresponding air requirements. The understanding of these variables is of prime importance to those concerned with the technical and economic development of in situ combustion as an oil-recovery process. The experimental results show conclusively that the fuel available for in situ combustion is not a constant but, rather, varies with crude-oil characteristics, porous-medium type, oil saturation, air flux and time-temperature relationships. Thus, the fuel availability for specified field applications should be determined using actual reservoir crude and core material and the process conditions expected during in situ combustion in the reservoir. INTRODUCTION In situ combustion is a thermal process for recovering crude oil from reservoirs. The thermal energy released during the combustion of a small amount of the oil in place aids in the displacement of the remaining oil. Numerous articles have been published describing the in situ combustion process giving detailed results of laboratory and field experiments.10 In order to engineer an in situ combustion project, a number of important factors must be considered and determined. These factors include: (1) the amount of fuel consumed per unit of reservoir volume swept by the combustion zone, (2) the composition of the fuel consumed, (3) the amount of air required to consume this fuel, (4) the portion of the reservoir swept by the combustion zone, (5) the appropriate air-injection rates and pressures, (6) the amount of oil that will be recovered, (7) the rate of oil production and (8) the operating costs. Nelson and McNiell1 recently have described a procedure which utilizes laboratory combustion-tube data as a basis for the calculation of some of these design factors. Various authors have attempted to describe the in situ combustion process mathematically, and considerable progress has been made. Analytical solutions to the problem of heat transfer from a moving combustion front have been obtained for linear and radial systems."-' All of the published results involve the assumptions that: (1) fuel concentration is constant throughout the reservoir, or that fuel concentration is inversely proportional to the velocity of the front for a given rate of oxygen consumption; and (2) the fuel reacts instantaneously with injected oxygen, while liberating a constant amount of heat per unit weight of fuel at all temperatures. It seems both desirable and reasonable to test the validity of these assumptions experimentally. This paper presents laboratory data which were obtained by means of a "fire flood-pot" method for determining fuel availability and composition, and the corresponding theoretical air requirements for in situ combustion of crude oils under variable conditions. The mechanics of the method are similar to a conventional tube-run experiment.' The important differences involve the size of the reservoir model used and the method for providing the experimental environment. The new method subjects conventionally-sized core samples or unconsolidated sands to a programmed environmental sequence similar to that experienced by a similar volume of rock during the approach and passage of a combustion front in a long tube or in an oil reservoir undergoing in situ combustion. Restored-state samples can also be used. The small samples and relatively simple techniques involved allow an experiment to be set up, run and calculated in about three 8-hour days. This is a considerable improvement over long-combustion-tube techniques which can require several days to run and several more work days to set up and calculate. All the runs presented were run at 40-psig injection pressure. Pressure was not considered as a variable for these experiments, since we previously had found that it had only a small effect on fuel availability up to 600 psig.APPARATUS AND MATERIALS APPARATUS The fire flood-pot apparatus consists of a consolidated

By Chu-Phay Yap

This is the second of a series of theoretical papers on the iron-carbon system. The solidus lines obtained as a result of the different methods of investigation fall naturally into three classes; namely, (1) a straight solidus originally suggested by Roozeboom and supported in the main by the work of Carpenter and Keeling, Andrew and Binnie, et al., using the thermal analysis method; (2) a slightly curved solidus obtained by Honda and his associates, using the magnetic and resistance methods: and (3) Gutowsky's solidus obtained by the Heycock and Neville method of quenching at successively higher temperatures. Although the thermodynamic method as shown in the first paper indicates that the straight solidus line is correct, no explanation has ever been advanced to account adequately for the disagreement in the shape and position of the solidus lines obtained. The nature of the solute in austenit.e is theoretically discussed. On the basis of such discussions, the data obtained by Honda and Endo on the change of magnetic susceptibility of steels with respect to temperature were critically subjected to a graphical analysis, which is shown to yield a rational explanation of the curved solidus lines.

Jan 1, 1931

By H. C. Gatos, A. D. Kurtz

WITH the growing interest in the mechanism of self-diffusion of metals, the study of accurate and convenient methods for determining self-diffu-sion coefficients appears highly desirable. It was with this objective in mind that the present investigation was undertaken. Gatos and Azzam1 employed an autoradiographic technique for measuring self-diffusion coefficients of gold. This method involved sectioning of the specimen through the diffusion zone and recording the radioactivity directly on a photographic film. Because of the very short range of the emitted ß rays in gold, the activity recorded on the film was essentially the true surface activity. With proper choice of the sectioning angle, sufficient resolution could be obtained and the entire concentration-distance curve recorded in one measurement. For the boundary conditions of the experiment, where an infinitesimally thin layer of radioactive material diffuses in positive and negative directions into the end faces of a rod of infinite length, the solution of the diffusion equation is C/Cn = 1/v4pDt exp (-x2/4Dt) where C is the concentration of diffusing element (photographic density in this case), C,, is the constant (depending upon amount of radioactive material), x is the diffusion distance, D is the diffusion coefficient, and t is the time. Thus, by plotting the logarithm of the concentration vs the square of the diffusion distance, a straight line results and the slope contains the diffusion coefficient. In this manner, the self-diffusion coefficient of gold can be obtained as a function of temperature. In the present investigation the results reported by Gatos and Azzam1 have been verified, and the autoradiographic technique has been further developed and applied for the determination of the self-diffusion coefficient of gold at a number of temperatures. Furthermore, the energy of activation for the self-diffusion of gold has been conveniently determined. . Experimental Techniques Preparation of Specimens: The inert gold of high purity was received in the form of a rod from which cylinders were cut and machined to a diameter of 0.500 in. The specimens were annealed to a suitably large grain size and the faces were surface ground prior to the deposition of the radioactive layer. The radioactive isotope Au198 was chosen. It was produced in the Brookhaven pile by means of the reaction Au197 + n ? Au108. It decays by ß emission (0.96 mev) to Hg108 with the subsequent emission of a y ray (0.41 mev). 70Au 108 ? 80Hg 108 + -1e°. The half life of the Au108 is 2.7 days so that a strict time schedule had to be maintained in order to secure sufficient activity until the end of the experiments. For this reason, initial activities as high as 10,000 millicuries per gram were used. The gold arrived in the form of foil and was evaporated onto one face of each gold specimen cylinder to a thickness of about 100A. A sandwich-type specimen was formed by welding two such cylinders together. Evaporation of Gold: The gold was evaporated under vacuum from heated tantalum strips which were bent in such a way as to limit the solid angle through which the gold was allowed to vaporize, thus insuring a more efficient utilization of the gold. The specimens rested on flat brass rings which had an inner diameter of 0.475 in. The entire specimen-holding assembly could be manipulated from outside the vacuum system by means of a magnet which attracted a slug of soft iron attached to the assembly. By evaporating inert gold on glass slides under conditions identical to those employed for the radioactive gold, it was found that the thickness of the films was about 100A. Welding: The welding was performed by hot pressing in a stainless steel cylinder. The inside of the cylinder was threaded and fitted for two plugs. The specimens to be welded were placed in the middle of the cylinder and two pressing disks, one at each end, were inserted to avoid shearing stresses as the plugs were tightened. Mica disks were placed between the pressing disks and the specimens to prevent them from welding. The plugs were then tightened with a hand wrench and the entire unit was placed in an argon stream for about an hour to remove the oxygen. The unit was then inserted in the center of an argon atmosphere furnace maintained at about 700°C and left there for about an hour. Because of the difference in the temperature coefficient of expansion of the two metals, as the temperature rose. the pressure on the specimen-rollple increased and a weld resulted Welding was generally satisfactory under the conditions described.

Jan 1, 1955

By D. G. Westlake

Resistance was measured as a function of temperature, 77° to 350°K,for niobium with hydrogen concentrations up to 3.76 at. pct. Cooling curves exhibited a discontinuity in slope that was attributed to the initiation of hydride formation. A thermal hysteresis was explained in terms of diffusion and the effects of mechanical constraint on nucleation and growth. The heat of solution of hydrogen in saturated Nb-H solid solution was 2. 737 * 0.045 kcal per g-atom, including an unknown stress contribution. The critical ternperatures for hydride formation during cooling and for embrittlement are correlated but not coincident. This, too, has been explained in terms of mechanical constraint and stress-itlduced tratzsfomtation. Nb-H alloys undergo a ductile-brittle transition with decreasing temperature.'-3 Similar behavior has been noted for v-H.1,5 For the latter system, there is evi-dence6 suggesting coincidence of the temperature of minimum ductility and the critical temperature T, for initiation of metal hydride precipitation during cooling. A decrease in ductility due to the presence of brittle hydride particles is readily explainable. The fact that ductility begins to decrease at some temperature higher than T,4,5 has led us6 to suggest that precipitation may be strain-induced locally during tensile testing. Wood and Daniels' have reported that a plot of temperatures for 10 pct reduction in ductility vs hydrogen concentration in niobium is not coincident with, but parallels, the solvus.7,8 They believe this indicates a correlation of precipitation and embrittlement. Unfortunately, the two reported solvuses 7,8 to which Wood and Daniels refer are not in agreement with each other. Furthermore, neither solvus was determined experimentally: each was a plot of calculated solubilities. Thus. neither is highly dependable for determining whether embrittlement coincides with initiation of hydride precipitation. Longson 9 studied phase relations in the Nb-H system between 77° and 473°K by dilatometry. Comparison with metallographic observations convinced him that discontinuities in the slopes of his dilatometric plots were coincident with the initiation of hydride precipitation. Plotting the logarithm of the hydrogen concentration vs the reciprocal of the temperature at which precipitation was initiated during cooling, he obtained a straight line shown in Fig. 1. Walter and chandler,'' using X-ray techniques to detect the for mation of a second phase? have obtained three experimental points in the temperature range 295° to 338°K which fall within Longson's experimental error for this plot. A similar plotg of temperatures at which dissolution was completed during heating was a parallel line shifted toward higher temperatures. A straight-line plot was obtained, also, for the temperatures of the ductile-brittle transitions,9 but it was shifted toward still higher temperatures. Longson calculated an activation energy of 2.980 * 0.300 kcal per mole for the hydrogen embrittlement mechanism, compared with 3.180 * 0.400 kcal per mole for hydride formation. Despite this agreement, he concluded, "It seems unlikely that embrittlement results from hydride formation..." because hydrogen embrittlement was observed at temperatures above the solvus. It is our contention that embrittlement is correlated with precipitation of the hydride.6 Because only Longson has investigated Nb-H phase relations at sub-ambient temperatures, we deemed it advisable to re-determine the temperature dependence of the solubility using the resistometric technique already proven successful for the V-H system.6 Coincidence of our solvus with temperatures for embrittlement would

Jan 1, 1970

By C. L. Magee, H. W. Paxton

The effects of testing temperature, frorn 77" to 420" K, and volume fraction of martensite on the micro-plastic response of unaged Fe-31Ni martensite-austenite aggregates have been determined. The kinetics of the aging phenomena which lead to a decrease in the microplastic response were also characterized. These determinations, supplemented by other experimental results, show that at least two mechanisms of plastic deformation give rise to the apparent softness of the quenched structures. Only one of these mechanisms is fully discussed in this paper The transformation of retained austenite to martensite during the application of stress leads, in specified conditions, to large microplastic strains. This deformation behavior cannot be described by normal transformation plasticity theory but is shown to result from the fact that stress-assisted formation of martensite is a possible deformation mode. The present results and further considerations of previous work lead to the conclusion that it is unnecessary to postulate a special work-hardening mechanism to explain the mechanical properties of unaged martensite. It is now generally accepted that dislocation motion can occur in many solids at stresses very much below the L'macroscpic" yield stress, e.g., 0.1 pct offset. This phenomenon has been investigated by a variety of techniques including measurements of elastic limit,' effective static elastic modulus,~ and irreversible deformation following stressing at low levels.3"5 Of particular interest to the work to be described are exper -iments conducted on the deformation of martensite in attempts to decide whether freshly quenched ferrous martensites are "hard" or "soft".6 Muir, Averbach, and cohenl and McEvily, Ku, and ~ohnston' have shown that as-quenched ferrous rnartensites can be plastically deformed at relatively low stresses. A difference between these two sets of experiments exists in that some diffusion of carbon would take place before testing in the experiments of Muir et a1. because the plain Fe-C alloys which they have tested transform to martensite well above room temperature. McEvily et a1. examined Fe-Ni-C alloys with Ms of about -30"~ and tested the alloys directly after quenching to — 195" ~ —a technique which obviates any appreciable carbon diffusion. Unfortunately, a characteristic of the alloys which transform below room temperature is that they do not transform entirely to martensite. The results discussed below will show that, because the transformation of this retained austenite under stress leads to plastic deformation, one cannot investigate the properties of martensite by such experiments. The existence of a second deformation phenomenon, which is not caused by retained austenite, is also established in the present work. In line with a previous suggestion,' it is believed that the second microdefor-mation mode is principally due to the internal stresses generated by the formation of martensite. To avoid confusion in the present report, the evidence we have found for this interpretation will be discussed separately in a brief note.7 EXPERIMENTAL Materials. The alloys were induction-melted and cast under vacuum; the resulting compositions are given in Table I. The ingots were hot-swaged to 2-in.-diam bar and further cold-swaged and/or cold-rolled prior to specimen preparation. The standard tensile specimens were machined from sheet. The gage section was 0.05 by 0.2 by 5 in.; 0.75-in.-wide ends had 0.2 5-in. centered holes for pinloading. The three-point bend samples were 0.075-in. thick and 0.6 in. bide. The distance between the outer loading points was 5.5 in. In order to establish a standard starting condition, all specimens were quenched to 77°K prior to annealing in vacuo for austenitizing. The temperature of the austenitizing anneal was controlled to + 5"~. The testing and aging temperatures were maintained by various liquid baths (nitrogen, 77"~; freon, 130° to 200°K; acetone, 200 to 300°K; silicone oil, 300' to 450°K) to better than il°K. Strain Measurement. The results herein were derived from both uniaxial tension and three-point bending experiments. For bending tests, the stresses and strains reported are those corresponding to the maximum fiber values. Normally, because of the small strains involved, very sensitive strain measurements are necessary to make microplastic measurements. However, because of the magnitude of the dilatation and shear involved in the martensitic transformation, the requirements in the present experiments proved to be less rigorous. In most experiments the plastic strain was evaluated by measuring stress relaxation and modulus defects. In this method, specimens are loaded rapidly to some predetermined load on an In-

Jan 1, 1969

H. Van F. Furman, Denver, Colo. (communication to the Secretary): There are some statements in Dr. Carpenter's interesting paper which appear to require explanation, if not modification.

Jan 1, 1901

By O. Chanute

all of' level atid grade curve excepting Nos. 897, 898, 899, and 900, because of the impossibility of grouping them in the same nlonner, no two Iraving the chemical composition and physical prnprtiw as tho only v:iriubles. Phosphorus ~tnits have been taken to show the relatia h:wdnes. Of these 16 groups, 10 decidedly indicate slower wear firr tile harder rail. Of the remaining 6 groups, three (groups 2, 9, and 15) come well within the limits of error (.25 pound per yard) inherent in the palculation of the data as pointed out by Dr. Dndley; they catrnot, therefore, be considered tls exceptions. Group 2 and 15 arc but little outside of the limita of error. Rail 923 of group 9 is obviously abnornlal. This is probahly due to its being overheated, which the chemical analysis shows might easily be the case, and which the physical tc~ts and its low specific gravity tend to c-nfirm. We inry say, then, thnt 13 of these 16 groups fairly indicate, if they do not definitely point out, th:kt, under the same condition% tbe harder rail gives the slower wear. Of course, these comparisons are too few to enable us to arrive at positive ~?o-nclusions; but indications thus obtained are, I believe, fir more vsluitblc and tresttvc~rthy than those fhzt averages rvottld give us, mnde up from any ~lumhr of rails under intloy difi~rcal, conditions. Finally, it, seems to me, that the conclusions arrived at earlier in my remarks, together with, and confirmed by the last, show strong evidence that, under the same conditions, the harder rail will givc the slower wear. 0. C~~anute, New York CITY: We are very much shlipl, 1 ant sure, to Mr. Sandberg for his paper upn " Rail Ryaifications and Rail Inspertion in Europe." We have in thp United States bithhrto Been inspecting mils sonlewl~at haphazard, and we ore glad to gtbt tfie results of Mr. Sandberg's long experience. We recognize that he was an)ong the first, if not the very firwt, to iipply mare rittional and scientific rules to the designing of irou rails., niora recently, to adapt tlitve rules to the clesigtting of steel I':I~]R, to conform to the oapaljilities and rqniretnento of this new n1:ttcrial. Although we have generally adopted, in this country, sectinns for hteel rails which marly of our railway men think even bottar than those of Mr. Snlldlmrg, he is neverthelees the Ieat3er in foot.iito11~ we have followed ever since it has been est~blished

Jan 1, 1881

By R. L. Bleifuss

The object of this study was to evaluate the oxidized taconites of the western Mesabi iron range and to establish a correlation between the various basic taconite types and their concentratability. The initial work included a study of the original mineralogical and stratigraphic facies of the fresh taconite and traced the oxidation and leaching patterns developed during the conversion of this material to oxidized taconite. Subsequent studies have extended this work to include the semitaconites and also the wash and heavy media ore types widely developed in the area. Each basic original mineralogical facies or taconite type produces during alteration an equivalent secondary oxidized facies which has a unique mineralogical composition and texture. These control the concentratability of the oxidized taconites. Actually the influence of the original mineralogical composition of the iron formation extends even further and determines whether the most likely product of oxidation and leaching will be a wash ore or a heavy media ore and even to the direct shipping ores where the ratio of hematite to goethite is largely determined by the original taconite type. The relationship between original taconite, oxidized taconite, semitaconites, and wash and heavy media ores is briefly summarized in Table I. The terms are not precise and in some instances tend to overlap. The table is intended to point out only the essential differences between the various materials. The original taconite was dominantly composed of mixtures of magnetite, iron carbonate, iron silicate, and quartz (chert). In a few thin stratigraphic units, hematite was present as an original constituent. The alteration of the original taconite to oxidized taconite has resulted from the circulation of ground waters through an initial fracture system related to minor structures in the iron formation. The chemical reactions have involved the oxidation and decomposition of original minerals such as magnetite, iron carbonate, and iron silicates to hematite or goethite. The alteration at this early stage is characterized by pseudomorphic replacement of the original minerals by oxidation products although retaining the major textural features of the original taconite. There was very little secondary migration of iron at this stage and the total iron content of the rock has been only slightly increased. Further alteration of this material to form a semi-taconite, a wash or a heavy media ore, involves extensive removal of silica in solution and significant redistribution of iron units. Wash and heavy media ores are developed by the growth of coarse secondary iron layers, dominantly goethite, coupled with the removal of silica in solution and decomposition of the cherty layers. This paper is concerned primarily with the materials classified as oxidized taconites which are characterized by oxidation of the original mineral constituents with little secondary enrichment. The area studied, shown on the index map, Fig. 1, extends some 30 miles along the strike of the Biwabik formation roughly from Hibbing to Coleraine. This study was greatly facilitated by the basic stratigraphic and mineralogical studies of Gruner1 and white2. The bulk of the material in this presentation represents a portion of the author's contribution to a study sponsored by the Great Northern Railway on the oxidized taconites of the western Mesabi.3 METHOD OF APPROACH A total of 106 drill holes, representing some 30,000 ft of drilling, were examined and sampled. The drill holes were logged and some 1500 composite samples were prepared for chemical analysis and bench scale metallurgical tests. These samples were analyzed for total iron and ferrous iron; and magnetite iron was determined by a standard Davis tube test at minus 200 mesh. Standard reduction roast tests using 150-gram samples of minus 10 mesh material were made on these 1500 composite samples with a mixture of H2, CO2, N2, and H2O at a temperature of 650°C. This roasted material was pulverized through 150 mesh and concentrated in the Davis tube. The iron recoveries and concentrate grades obtained on the roasted products were used to assess the concentratability of the oxidized taconites. Detailed mineralogical work was done on thin sec-

Jan 1, 1964

By Roussey Roussev

The use of chemical additives on grinding is of significant importance considering the high energy consumption of grinding processes. My research indicates that the dispersant approach explains the effects, in this particular case of wet grinding. Further, the dispersant approach combined with torque measurements give the possibility of clarifying the mechanisms involved when using grinding aids. I find the conclusions derived from the data obtained to be correct and useful for grinding. In general, I agree with the explanations. However, I would like to discuss several additional points that I consider to be important, and in the same time to mention some of my own results from investigations similar to those presented in the study under discussion. The "bed volume concept" and the change of slurry viscosity explain adequately the data plotted on [fig. 3], in conjunction with [Figs. 1 and 2]. However, the significant increase of the average torque in the case of 83% solid with XFS-4272 introduces the necessity of establishing the optimum of percent solid when dispersant is used. For example, the optimum percent of solid for different materials varies. One of the reasons is the material's mass density. On the other hand, it is necessary to determine the concentration of the chemical used. Because of this, it would be interesting to know how the cited concentration was selected.

Jan 1, 1983

By Stanley Gill

The apparatus is composed of sections of small diameter, seamless steel tubing welded into a continuous flexible tube. At the bottom end a 1/4-in. pipe nipple with a 10 to 15-lb. weight is attached, together with a registering thermometer and a pair of ball check valves. The entire length of tubing is coiled in a single layer upon a drum 4 ft. in diameter which can be attached to the platform of a truck and provided with devices for winding and unwinding the tubing. Connections are made with the upper end of the tubing through a stuffing box, thence to a gas manifold to which a pressure gage is connected. Hydrogen gas is carried in standard 2-ft. cylinders and readings are taken by admitting gas into the tubing from one (or both) of the hydrogen cylinders until the pressure has been built up above that to be measured. At this time the gas supply is cut off. Excess gas escapes through the open end of the tubing and when equilibrium is reached, the pressure is read at the surface gage. Corrections are made for the weight of the column of gas. The advantages claimed for the apparatus include accuracy and the ability to measure the pressures at any number of points without removing the gage. Among the disadvantages of the apparatus are the somewhat bulky size of the equipment and its relatively high initial cost.

Jan 1, 1933

By Herbert Clark Hoover, Lou Henry Hoover

GEORGIUS AGRICOLA was not only the author of works on Mining and allied subjects, usually asso ciated with his name, but he also interested himself to some extent in political and religious subjects. For convenience in discussion we may, therefore, divide his writings on the broad lines of (1) works on mining, geology, mineralogy, and allied subjects; (2) works on other subjects, medical, religious, critical, political, and historical. In respect especially to the first division, and partially with regard to the others, we find three principal cases : (a) Works which can be authenticated in European libraries today ; (b) references to editions of these in bibliographies, catalogues, etc., which we have been unable to authenticate ; and (c) references to works either unpublished or lost. The following are the short titles of all of the published works which we have been able to find on the subjects allied to mining, arranged according to their present importance :-De Re Metallica, first edition, 1556; De Natura Fossilium, first edition, 15,46 ; De Ortu et Causis Subterraneorum, first edition, 1546; Bermannus, first edition, 1530 ; Rerum Metallicarum Interpretatio, first edition, 1546; De Mensuris et Ponderibus, first edition, 1533; De Precio Metallorum et Monetis, first edition, 1550 ; De Veteribus et Novis Metallis, first edition, 1546; De Natura eorum quae Effluunt ex Terra, first edition, 1546 ; De Animantibus Subterraneis, first edition, 1549. Of the " lost " or unpublished works, on which there is some evidence, the following are the most important:-De Metallicis et Machinis, De Ortu Metallorum Defensio ad Jacobum Scheckium, De Jure et Legibus Metallicis, De Varia Temperie sive Constitutione Aeris, De Terrae Motu, and Commentariorum, Libri VI. The known published works upon other subjects are as follows:-Latin Grammar, first edition, 1520; Two Religious Tracts, first edition, 1522; Galen (Joint Revision of Greek Text), first edition, 1525 ; De Bello adversus Turcam, first edition, 1528 ; De Peste, first edition, 1554. The lost or partially completed works on subjects unrelated to mining, of which some trace has been found, are:-De Medicatis Fontibus, De Putre¬dine solidas Partes, etc., Castigationes in Hippocratem, Typographia Mysnae et Toringiae, De Traditionibus Apostolicis, Oratio de rebus gestis Ernesti et Alberti, Ducum Saxoniae.

Jan 1, 1950

By John L. Walter

A sintered compact of iron containing 0.007 vol fraction of glass , prepared 6). powder rnetullurgtcal lechniques, was rolled lo foil, 0.001 in. /hick. The foil sullrples were anneuled a1 650° to 850°C in hydrogen. Pri,narj recryslullization prodtnced large grains which Lc3ere highly elongnled in the rolling direclion und which had an unusual prgferred orientation. The glass parlicles assumed a stringerlike dispersiorz on working; llie slrinyers were parallel lo the rolling direction and to the long axis of the grains. The same unusual grain structure, preferred orientation, and stringerlike dispersion of purticles are found in heal-ily rolled and annealed foil of tungsten which has heen doped wilh small amounts of aluminum, silicon, and polassiutvt. Both the proper dispersion of the particles and severe working (reductions in excess of 98 pct) are necessary to produce the elongzcted grain structure. RECENTLY, the author reported on the origin of the elongated or "nonsag" grain structure in tungsten foil which was doped with aluminum, silicon, and potassium.' It was observed that particles, identified as mullite (Al6Si2Ol3), were present in the doped ingot (as sintered) and at all stages of processing from ingot to sheet or wire. It was shown that the particles, being plastic at tungsten working temperatures (up to 1550"C), underwent a "stringing out" parallel to the working di-direction. It was concluded that these strings of particles were responsible for the formation of the highly elongated interlocking grains observed in doped tungsten wire or sheet. To give further credence to this explanation of a long-observed but not understood phenomenon, it was decided to design a new system, one which was analogous to the doped-tungsten system. Thus, a bcc metal, iron, was chosen to be doped with glass which would be plastic at reasonable working temperatures for iron. The glass chosen was a #0080 Corning lime glass which melts at about 810°C. This is approximately the same fraction of the melting point of iron (0.6) as the melting temperature of mullite is of tungsten. It will be shown that all the observed unusual features of the doped tungsten are duplicated in the glass. doped iron, even to the preferred orientation of the grains in the recrystallized sheet. In the tungsten sheet the preferred orientation consists of two components, (1i3)(691) and (013)(362), neither of which has been observed as a component in textures of primary recrystallized bcc metals. EXPERIMENTAL PROCEDURE The glass, in the form of fine powder, was added to high-purity electrolytic iron powder and mixed dry. The particular composition chosen was 0.007 vol fraction of glass. After mixing, the powder was mechanically pressed to a disk 0.5 in. diam and 0.15 in. thick at a pressure of 5000 psi. The pellet was sintered, in pure dry hydrogen, for 2 hr at 8 50°C. The sintered pellet was then heated to 750°C and rolled to 50 pct reduction of thickness in two passes, with reheating between passes. The rolling temperature was then reduced to 600°C and the slab was rolled to a thickness of 0.050 in. Rolling to 0.010 in. was accomplished in several passes at 300°C. Final reductions to 0.003 and 0.001 in. were taken at room temperature. This rolling temperature schedule was similar, in terms of the fraction of the melting point, to that used in the rolling of the doped tungsten. The total reduction of thickness was in excess of 99 pct. Samples of the rolled foil were lightly electro-polished and annealed for 1 to 6 hr at temperatures of 650" to 85O°C in hydrogen. Samples for transmission electron microscopy were thinned on a Disa Electropol using AC-1 electrolyte.

Jan 1, 1968

By Paul J. Bennett, James E. Castle

The kyanite minerals, including kyanite, silimanite, and andalusite, are anhydrous aluminum silicates with the formula Al2O3SiO2. lumortierite and topaz are also included in this group because they are closely allied in composition and thermal behavior. However, leither are mined commercially today. They ire typical metamorphic minerals which are found in metamorphic rocks on every continent. Kyanite minerals are prized chiefly for their refractoriness and are important components in a broad range of acid refractory products, especially in mortars and castables. World production of kyanite minerals is currently about 250,000 tpy and has been increasing at the rate of 3 to 8% a year for many {ears (Anon, 1972). While kyanite minerals lave widespread occurrence, the consumption of kyanite minerals is concentrated in the relatively few highly industrialized areas where refractories are manufactured, and which in turn are typically close to the major iron and steel producing regions of the world. Thus northern Europe, England, the United States, and Japan are the principal consumers of refractories and kyanite minerals. Of these countries only the U.S. is a significant producer. The largest use for domestic kyanite, both raw and calcined, is in the manufacture of refractory mortars, cements, castables, and plastic ramming mixes. In these applications kyanite constitutes from 10 to 40% of the mixture, the balance being refractory clays and coarser grog materials. A certain proportion of raw kyanite is used to offset the shrinking of the clay binder, whereas the calcined kyanite is used in the coarser sizes for body. Certain high grade refractory shapes and kiln furniture are composed chiefly of graded sizes of calcined kyanite bonded with a little ball clay. In most applications, however, kyanite is used only to fortify the mix or as a minor ingredient. Some manufacturers of mullite brick use domestic calcined kyanite for the fine-grained portion of the brick, but seldom in quantities exceeding 10% by weight. Kyanite is used by ceramic manufacturers of wall tile and sanitary ware to offset shrinkage and cracking after firing. Indian kyanite has traditionally been used to make the coarse grog sizes needed for the manufacture of mullite brick, and for the grog portions of mortar, cement, and castable mixes. It has been largely replaced, however, by synthetic mullite, high fired flint, and diaspore clay or calcined bauxite for other applications. Indian kyanite is available in lump as well as in granules and concentrates, as are sillimanite materials from India and South Africa. Andalusite is available as 8 mesh granules and as fines with chemical analyses not unlike those of domestic kyanites. From time to time and from place to place minor amounts of other aluminum silicate minerals such as dumortier- ite, topaz, and pyrophyllite have been made available at various prices and specifications, but have not been significant factors in the refractory industry. A mixture of kyanite and sillimanite of relatively fine grain-size and of low iron content was at one time offered to the molding sand industry by the Du Pont Co. as a byproduct from their deposits of heavy

Jan 1, 1975

By B. D. Smith, K. H. Coats

Experiments in which calcium chloride displaced sodium chloride from four cores showed the extent of asymmetry in the resulting effluent concentration profiles. These results provided a check on how validly the mixing process is modeled by a differential (i.e., not finite-stage) capacitance mathematical model. The effluent concentration profile from two consolidated cores exhibited considerable asymmetry, while two unconsolidated cores yielded nearly symmetrical profiles. All runs resulted in breakthrough of the 50 per cent concentration significantly before one pore volume was injected. In addition, velocity appreciably affected the effluent concentration profile from a Torpedo sandstone core. The differential capacitance model matched the data significantly better than a simple diffusion model. The capacitance model allows determination of the amount of dead-end pore space in a porous matrix and the effect of velocity on the rate of diffusion into this space. An experimental program yielding insight into the physical validity of the capacitance effect is described. INTRODUCTION Axial dispersion — the mixing accompanying the flow of miscible fluids through porous media — has been the subject of many relativeiy recent studiesl-13 and a comprehensive review of the topic has been given by Perkins and Johnston.14 This dispersion is of practical interest in studies of the miscible displacement process, fixed-bed chemical reactors, and the adsorption of solutes from a flowing stream onto the surface of a porous medium. In the latter case, the effect of dispersion must be considered when adsorption parameters are determined from the nature of concentration profiles. In general, early studies of dispersion assumed applicability of a simple diffusion equation and were concerned with correlation of the experimentallv determined "effective" diffusion coefficient with system properties over a large range of the latter. Recent have been concerned with the deviations between the asymmetrical effluent concentration profiles observed and the symmetrical ones predicted by the diffusion model. In the present study, effluent concentration profiles were obtained from consolidated and unconsolidated cores. These profiles were compared with those predicted by a differential (i.e., not finite-stage) capacitance model. Solutions to the simple diffusion model, for three sets of boundary conditions, were compared with one another and with the experimental profiles. SUMMARY OF PREVIOUS WORK The reader is referred to Perkins and johnston14 for an extensive review of studies of dispersion in porous media. Many investigators have employed the simple diffusion model characterized by Eq. 1 below: The dispersion coefficient D for unconsolidated systems is correlated by u is interstitial velocity and dp is particle diameter. Since heterogeneity of the sand pack affects the mixing, this equation is also expressed as where a is proportional to the degree of heterogeneity and is about 3.5 for random packs of unconsolidated sand.l4 Eq. 3 holds for 2 For a Do homogeneous (regular) type of packing, should be 1 or less.6 Aris and Amundson6 and Carberry and Bretton consider o to be the number of particle lengths per mixing cell in the finite-stage model. Data from consolidated cores indicate dp to be about 0.36 cm for outcrop rocks, Torpedo sandstone having a reported value of 0.17 cm.15 For v /Do less than about 2, the effect of molecular diffusion must be considered and the total dispersion coeffi-

Jan 1, 1965

By William E. Ford, Edward Salisbury Dana

1. Normal Class (31) Axinite Type 2. Asymmetric Class (32) Calcium Thiosulphate Type Mathematical Relations of the Triclinic System 216. Crystallographic Axes. - The triclinic system includes all the forms which are referred to three unequal axes. with all their intersections oblique. When orientated in the customary manner one axis has a vertical posi-

Jan 1, 1922

By Donald H. McLaughlin

MINERAL industry activities have not been seriously hampered by a lack of men with higher training. The balance between opportunities for employment and advancement and available personnel has been a happy one, with enough competition to stimulate effort but not the unfortunate conditions arising from an overabundance. of employment seekers. Nearly all mineral industry educational institutions have been concerned about the falling enrollment in mining and metallurgical courses of study during the past decade. But industry has drawn upon a supply of many types of technically trained men apart from those who prepared their careers specifically in the mineral industry. Some schools have made this possible by uniting geologists, mineralogists, and others with students in mining and engineering. On the other hand, some schools have combined their department of mining engineering with an over-all engineering department and continue to send their graduates into the mineral industry by another route. On the whole, this seems to be a good trend and is likely to result in men better trained for current problems than would have been possible under the older rigid curricula.

Jan 1, 1947

ARTICLE I NAME AND OBJECT SEC. I. This Institute is incorporated under the Membership Corporations law of the State of New York; its corporate name is American Institute of Mining and Metallurgical Engineers, Inc.; and its objects are such as are stated in its Certificate of Incorporation. ARTICLE II MEMBERS SEC. 1. The membership of the Institute shall comprise four classes, namely: 1. Members; 2. Honorary Members; 3. Associates; 4. Junior Associates. All members shall be equally entitled to the privileges of membership, excepting that Honorary Members, Junior Associates, and Members and Associates whose residences shall be outside of the United States, Mexico, and Canada shall not be entitled to vote. Members and Associates residing within the United States of America, Mexico, and Canada, .and not in arrears for dues, shall be entitled to vote in person at the meetings of the Institute, or, as hereinafter provided for, by letter ballot. SEC. 2. Members shall comprise all those persons who on the third Monday of February, 1918, were members of the Institute, and in addition thereto, all those thereafter elected or transferred into the class of Members. A person to be eligible for election or transfer into the class of Members must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. Graduation from the scientific course of a college, approved by the Committee on Membership, shall be considered equivalent to two years' employment, as required in the previous sentence. Employment as a teacher of engineering, mining, geology, metallurgy or chemistry, if in direct charge, may be considered a position of responsibility as specified in the second paragraph. Persons employed in research or any scientific literary work or in teaching in the scientific departments of colleges, approved by the Committee on Membership, who at the same time are engaged in consulting or in the active practice of mining, geology, or metallurgy, shall be entitled to consider the time so spent in active practice as equivalent to an equal length of time of employment in positions of responsibility, provided the work done or the positions held seem to the Committee on Membership to warrant the equivalency. The requirement of three years' employment in positions of responsibility maybe waived by the Committee on Membership in the case of persons who have done notable original work in mining, geology, or metallurgy, or have won distinction by

Jan 1, 1925

By J. S. Levine, M. Prats

A homogeneous and uniform cylindrical reservoir containing oil and gas is fractured vertically on completion and is produced at a constant bottom-hole pressure. The fracture has an infinite flow capacity, is of limited lateral extent and is bounded above and below by the impermeable strata defining the vertical extent of the reservoir. Results show that such a fractured reservoir can be represented by a reservoir of circular symmetry having very nearly the same production history. The well radius of this circular reservoir is about 1/4 the fracture length and is essentially the same as that obtained previously for a single fluid of constant compressibility. At the same value of cumulative oil production, gas-oil ratios of fractured reservoirs producing at constant terzinal pressure are larger than those of reservoirs having no fractures. This leads to more inefficient use of the reservoir energy in fractured wells and results in lower reservoir pressures for the same cumulative oil production. The reduction in operating life due to fracturing a reservoir is not as great as that for a slightly compressible fluid. This diflerence can be accounted for by the lower reservoir pressure in the fractured reservoir and its adverse effect on the average mobility and compressibility of the oil. As anticipated, the reduction in operating life increases czs the reservoir permeability decreases. The type of results presented in this report can be used to determine the economic attractiveness of fracture treatments per se, to setect the initial spacing to be used in developing a field, and to compare the relative merits of fracturing available wells and infill drilling. INTRODUCTION The effect of vertical fractures on a reservoir producing either an incompressible or a compressible liquid has already been discussed in the 1iterature.l,2 Those results indicate that the production history of such a reservoir is essentially the same as that of a circular reservoir having an effective well radius of approximately one-fourth the fracture length. The present work reports on the effect of a vertical fracture on a reservoir producing two compressible fluids —oil and gas—by solution gas drive. Because of the empirical nature of the PVT and relative permeability data used to obtain the performance of such reservoirs, results can only be obtained numerically and with the aid of high-speed computers. Since reservoirs lose their radial symmetry when fractured vertically, pressure and saturation can no longer be given only in terms of distance from the well. Two coordinates (such as x and y) must now be used to describe the pressure and saturation within the reservoir, and, since we are dealing with compressible fluids, time is also a variable. Thus the solution of a vertically fractured reservoir requires finding two unknowns (pressure and saturation) in two space variables (say x and y) and in time (t). Since no means are readily and generally available for solving such problems at the present time, we have used the results of previous work1,2 to approximate the effect of a vertical fracture on a reservoir producing both oil and gas by depletion. The purpose of the present wmk, then, is to investigate the possibility of using available numerical techniques (limited at the moment to one space variable) to study the two-space-variable flow behavior resulting from a vertical fracture. Results obtained in the course of this investigation are also reported and discussed. Input and output data of the numerical methods used are given in practical units: BOPD, feet, psi, cp, and md. Results are discussed fist in terms of specific reservoir and crude properties and geometries. Later, dimensionless parameters are introduced in order to extend results to different values of some of the reservoir and fracture properties. IDEALIZATION AND DESCRIPTION OF THE FRACTURED SYSTEM It is assumed that a horizontal oil-producing layer of constant thickness and of uniform porosity and permeability is bounded above and below by impermeable strata. The reservoir has an impermeable, circular, cylindrical outer boundary of radius r,. The fracture system is represented by a single, plane, vertical fracture of limited radial extent, bounded by the impermeable matrix above and below' the producing layer (reservoir). It is assumed that there is no pressure drop in the fracture due to fluid flow. 1 indicates the general three-dimensional geometry of the fractured reservoir. Gravity effects and the effects of differential depletion resulting from variations in hydrostatic head (pressure) will be neglected. Thus, the flow behavior in the fractured reservoir is described by the