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By R. A. Harrington

THE structure of anodic films formed on aluminum and other metals under varied conditions is not well known despite the wide use of such films both as protective coatings and as the dielectric medium in elec-trolytic condensers. The present work was undertaken as a survey of the possibilities of electron diffraction in the investigation of anodic films, especially in comparing the properties of anodic films formed under dif-ferent sets of conditions and subjected to various subsequent treatments. In addition, an effort has been made to compare surface films formed on aluminum by anodic treatment with surface films formed by heating, immersion in chemicals, etc, The electron diffraction method in many cases has been successfully applied to the study of thin surface films. Its principal advantage is that it can be used without removing the films from the base material upon which they have been formed. The low penetrating power of electrons, in the "reflection" diffraction method which has been used in this work, prevents the appearance of diffraction patterns from substances at depths greater than about 100 Angstrom units (10-6 cm.). Different investigations of the structure of anodic films have shown widely varying results, depending on the methods used in preparing the films. Apparently under some conditions these films are crystalline and under other conditions they are amorphous, and it has been difficult to say which type of structure will be found in any particular case. Schmid and Wassermann's' X-ray diffraction patterns of eloxal? films show two broad, diffuse bands, which these investigators attribute to finely divided cubic y-Al2O3-§ Burgers, Claassen, and Zernicke3 obtained sharp X-ray

Jan 1, 1940

By Cyril Wells, Paul E. Busby, Donald P. Hart

EARLY workers in the field have established that the diffusion of nitrogen follows normal diffusion laws. Concentration-penetration data from layer analyses of reasonably pure iron specimens nitrided in an atmosphere of CO-NH, are given in the literature,' and were utilized to calculate diffusion constants for nitrogen. The diffusion of nitrogen in y-iron may be represented approximately by the equation D - 1.07x10-' e-:".'m'"'r The diflusion coefficients, D, given by this relation represent mean values, since carburization occurred simultaneously with nitriding. The rate of diffusion in a-iron has been determined from calculations based on data obtained by measuring the internal friction of samples at each of several frequencies and temperatures.' The expression for the diffusion of nitrogen in a-iron derived from these experiments is D= 1.4x10-1 e-it tudent Increasing carbon content decreases the diffusion of nitrogen in a-iron.3 Oxygen, either dissolved or combined, has been shown' to exert a marked influence on the diffusion of nitrogen from a nitriding atmosphere. D values increase rapidly with increasing amount of dissolved oxide in the metal, but diffusion is completely inhibited if preliminary oxidation has produced the slightest trace of iron oxide on the surface. Diffusion coefficients have also been calculated from permeability and solubility data,' but these values are of questionable accuracy since the boundary conditions assumed may not actually exist. Experimental Method The method selected for determining the diffusion coefficient of nitrogen in a-iron in the present investigation was the so-called fractional saturation method. This method consists of heating the specimen in an atmosphere of H2-NH8 mixtures of known composition for a predetermined time. Following this treatment, the specimen is analyzed for nitrogen; and the diffusion coefficient is calculated from a known relationship of the fractional saturation, time of diffusion, and dimensions of the specimen. This relation is based on a solution of Fick's second law and assumes that the surface of the specimen immediately reaches a given concentration which remains constant during the diffusion anneal. Tabular solutions are available4-5 and provide the relationship between fractional saturation and the quantity \/Dt /a, where D is the diffusion coefficient in cm2 per sec, t is the time of the diffusion anneal in seconds, and a, in the present experiments, is the half-thickness of the slab specimen in cm. The method is adequately discussed elsewhere.9-10 Material The material for this study consisted of 3/32 in. thick (0.24 cm) carbonyl iron plate. The major impurities in this iron are oxygen and carbon, which are readily removed by long time high temperature treatment in an atmosphere of purified hydrogen. In order to reduce the diffusion anneal time for saturation runs, some of this material was rolled to a thickness of 0.015 in. (0.038 cm) prior to the hydrogen treatment. Hydrogen treatments were carried out in a hydrogen-purified Armco iron tube heated in a global

Jan 1, 1957

By R. W. Gurry, L. S. Darken

The solubility of cementite in austenite is computed by thermodynamic methods from the observed solubility of graphite. It is found that the solubility of cementite is greater than that of graphite in the entire austenite temperature range. Thus the prior discrepancy between this portion of the phase diagram and the observed metastability of cementite is partially resolved. FOR several years it has been apparent that a serious discrepancy exists in certain observations pertaining to the Fe-C system. Direct experimental data indicate: 1-That the curve representing the solubility of graphite in austenite'" crosses that for cementite4 at about 945°C as shown in Fig. 1. 2— That graphite and austenite saturated therewith are stable1 relative to cementite at all temperatures between the eutectoid, about 723°C, and the eutectic, about 1153°C. These observations are mutually incompatible in view of a well-known consequence of the second law of thermodynamics, namely, that the stable phase (presumably graphite at all temperatures) has a lower solubility than the metastable phase (presumably cementite). Hence either 1 or 2 above must be in error; either the measured solubility of graphite or of cementite, or the observation as to the stability of graphite, is in error. Our present purposes are: 1—To collate the available data on cementite and prepare a table of HO — HO° and of (Fa— HO°)/T. This tabular method seems the best and most convenient way to represent the heat and free energy of formation. 2—To determine whether the measured solubilities of cementite and graphite in austenite are in accord with the above table and the measured thermodynamic properties of austenite, in order to resolve, if possible, the existing paradox of these two solubilities. Enthalpy of Cementite The enthalpy of cementite at 273 °K, H279 — HOcem, was computed by integration of the low temperature heat capacity as measured by Seltz, McDonald, and Wells" 68" to 298 °K) and as given by the Debye functions recommended by them (0" to 68°K); the result is included in Table I. At higher temperature HCem — H,,"" is given by Kelley who used the data of Naeser7 (298" to 1037°K) and of Umino8,9 (273° to 1923°K). We have recalculated Hcem — H273 cem from the data of UminoO in the following way. In the equilibrated alloy at temperature the weight fraction of cementite Pct c -Pct cr is PctC -PctCr designated f(C), and the

Jan 1, 1952

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Jan 1, 1938

By C. E. Melbye

A serious problem confronted the city of Gunnison early in 1958 in that, for a few months during each spring runoff, the water supply derived from the Gunnison River became polluted to an unsafe point. The city management had the choice of building a new filter plant to replace the old unworkable one or drilling wells to develop a ground water supply. The cost of a new filter plant was estimated at $180,000 compared to $50,000 for 6 wells, pumps, and additional water lines, hence their decision to attempt the development of sufficient ground water. Six wells at 300 gpm per well were estimated as necessary to handle the peak usage of 1800 gpm, compared to only 600 gpm winter usage. Although the water table is only about 7 feet below the surface, existing private wells drilled at random locations were producing much less than 300 gpm. The problem was to find sufficient quantities from about 6 wells. Since the presence of an ancient bedrock channel was suspected, which would be expected to localize greater quantities of water, the city of Gunnison authorized a resistivity survey to investigate bedrock topography below unconsolidated gravels. Survey results were highly satisfactory and led to the preparation of a fairly detailed bedrock contour map, Fig. 1. This map was used in selection of all well sites. The city of Gunnison is situated in a flat, broad, Quaternary gravel-filled valley (terrain dips south at 20 feet per mile) at the junction of the Gunnison River and Tomichi Creek. The valley, about 2-4 miles wide, is bordered by hills of Tertiary volcanics to the northwest, Cretaceous and Jurassic sediments to the north and northeast, and pre-Cambrian granite and gneiss to the south. One previous deep test well at the west end of the city hit pre-Cambrian granite at 496 feet, which, allowing for 40 feet of surface gravels, makes the older sedimentary section 456 feet thick. This section is probably all Jurassic Morrison formation, consisting of the Saltwash sandstone overlain by the much thicker section of Brushy Basin shales and mudstones. According to the driller's logs, each well was bottomed in what is believed to be Brushy Basin shale. FIELD PROCEDURE A standard Gish-Rooney type of resistivity apparatus was employed, which used 45-volt dry batteries as a direct-current power source. Applied voltages could be selected from 45 volts to a 270-volt maximum. Copper-coated steel stakes were employed as current electrodes and porous porcelain pots as potential electrodes to avoid possible polarization effects with direct current. The expanding Wenner electrode configuration was utilized for this investigation and measurements were made at 20 40, 60, 80, and 100-foot spacings,

Jan 1, 1961

By M. Murakami, Y. Murakami, O. Kawano

The formation and growth of Guinier-Preston zones in Al-Zn alloys containing 4.4, 6.8, 9.7, and 12.4 at. pct zn have been studied by the X-ray small-angle scattering method. Particular attention was paid to the effects of small amounts of third elements silver, silicon, and magnesium on the formation and growth of G.P. zones. It was noticed that an appreciable number of G.P. zones were formed during the course of rapid cooling and that the size, volume fraction, and number of these G.P. zones were influenced by the existence of the third elements. During subsequent aging it was also found that the addition of both silver and silicon lowered the temperature for the growth of G.P. zones, whereas the addition of magnesium raised it. These results were explained in terms of the mutual interactions among zinc atoms, vacancies, and the third elements. A number of studies on the formation and growth of Guinier-Preston zones in Al-Zn alloys have been reported.1-4 Panseri and Federighii have found that the initial stages of zone growth take place at temperatures as low as around -100°C. For investigation of the mechanism of the initial stages of zone growth, growth studies must be carried out at low temperatures. In order to investigate the possibility of the formation of G.P. zones by the nucleation mechanism or the spinodal decomposition during quenching which was reported by Rundman and Hilliard,5 the examination of the as-quenched structure must be performed. In this paper the investigation of the early stages of the formation and growth were determined by means of the X-ray small-angle scattering method. With this technique, change of X-ray scattering intensities was measured while quenched specimens were heated slowly from liquid-nitrogen temperature to room temperature. At as-quenched state and after heated to room temperature, investigation of zone size, volume fraction, and zone number per unit volume was carried out. Measurements on these specimens yielded information on the early stages of zone formation and growth. Measurements were made also on specimens quenched to and aged at room temperature. From these measurements the previously reported model6 for the later stages of growth is confirmed; namely, the larger zones grow at the expense of smaller ones. Three elements, silver, silicon, and magnesium, were chosen as the third elements for the following reasons: Silver. In the binary A1-Ag alloy the spherical disordered 77' zones were observed immediately after quenching.7 Therefore, in the Al-Zn-Ag alloys, it is suggested that silver atoms might induce cluster formation during quenching. Also, since the migration energy of the zinc atoms was found to be raised by the addition of silver atoms,' silver atoms may have a great effect of the zinc diffusion, especially during low-temperature agings. Silicon. The effects of the addition of silicon atoms were found to be marked, especially at low-tempera-ture aging. In the binary Zn-Si system, no mutual solid solubilities between silicon and zinc9 and no in-termetallic compounds10 are reported to exist. Shashkov and Buynov11 investigated the behavior of silicon atoms in Al-Zn alloys and showed that silicon was not in the G.P. zones. The interaction between silicon atoms and vacancies is strong enough to increase the quenched-in vacancy concentration.* Magnesium. Magnesium atoms are reported to trap quenched-in vacancies and after much longer aging times these trapped vacancies will become free and act as diffusion carriers.13 Therefore at intermediate aging times, the diffusion of zinc atoms in Al-Zn-Mg alloys will be slower than in the binary Al-Zn alloys, whereas at longer times zinc diffusion will become faster. EXPERIMENTAL PROCEDURE The alloys used in this investigation had compositions of 4.4, 6.8, 9.7, and 12.4 at. pct Zn with or without 0.1 and 0.5 at. pct Ag, Si, or Mg. The alloys were prepared from high-purity aluminum, zinc, silver, silicon, and magnesium, with each metal having a purity better than 99.99 pct. The analyzed composition of the specimens is given in Table I. The measurements of the X-ray small-angle scattering were carried out with foils of 0.20 mm thick. The change of the scattering intensity was always measured at the fixed scattering angle of 20 = 2/3 deg. This angle exists nearly on the position of the intensity maximum. The value of the interparticle interference function14 which has large effect in this range of angles may not change abruptly in the case of the spherical shape of small zones. Therefore, from the above considerations, it is concluded that an increase of the intensity measured at this constant angle corresponds to an increase of the average radius and volume fraction of G.P. zones. The specimens were homogenized at 500°, 450°, and 300°C for 1 hr in an air furnace. For the study of the formation and growth at low temperatures, the foil

Jan 1, 1970

By C. E. Corson

THE experiments of which the results and significance are set forth in this paper do not by any means cover the whole subject of the heat-treatment of the material referred to, yet they constitute a contribution to that general subject, rather than to the special department of annealing. The material here considered is acid open-hearth steel, containing from 0.50 to 0.80 per cent of carbon, with a nearly uniform percentage of other elements. This class of steel is rapidly increasing in commercial importance. It is even rumored that the rail-specifications of some railroads will hereafter require open-hearth steel. Yet this particular grade seems to have received less study and description from the standpoint of the metallographist than many others. The investigation here described was directed to the following points:-Steel containing about 0.50 per cent, of carbon : 1. The structure as related to the temperature, at the same rate of cooling; 3. The structure and physical properties as related to temperature at different rates of cooling; 3. The structure and physical properties as related to different finishing-temperatures and different rates of cooling; 4. The bearing of these observations upon the statement of Prof. Albert Sauveur.1

Sep 1, 1906

By E. P. Mathewson

W. W. (Pop) Adams' contribution is short and to the point. "I went to Pueblo about March, 1881, and started working for the Pueblo Smelting & Refining Co. in the sampling room, going from there to the assay and chemical departments, and ending in charge of the lead refinery on the night shift. I was there about two years, returning to California in 1883. The plant was under the management of Mather and Geist, plus Charley Ballard; Herman Schlapp was the metallurgist. Herman Schlapp's name remains prominently in my recollection of Pueblo for his never-failing kindness and charity to the young men who were trying to learn the Pb. game. John Allen, Walter Koehler, George Westcott, Charley Molson, and Alfred de Ropp were there with me. Schlapp and Koehler I have never seen since I left Pueblo; the others I have met often. , Alfred de Ropp I have often met-here, as he was manager of the Selby Smelting & Lead Co. of San Francisco, for years. 'He tells me that I gave him the rudiments. of American profanity at Pueblo; an apt pupil, for since then, by his own efforts, he has added largely to his vocabulary..

Jan 12, 1923

By Philip B. Bucky

CONTENTS [PACEPACE r. What Is a Rock Burst?2 4. How Can Rock Bursts Be Predicted? . 35 Jack Spalding2Jack Spalding35 A. F. Robertson 2, 5A. F. Robertson35 W. R. Crane 2A. B. Yates and P. J. Shenon. . . . 35 G. S. Rice 2W. R. Crane 35 P. J. Shenon 2G. S. Rice 35 L. C. Graton 2B. F. Tillson 36 2. What Are the Causes of Rock Bursts? 6 5. How Can Rock Bursts Be Controlled?. 36 Jack Spalding6Jack Spalding36 A. B. Yates and P. J. Shenon . 7, 12, 29A. F. Robertson 36 A. F. Robertson 12, 28W. R. Crane37 W. R. Crane 15A. B. Yates and P. J. Shenon. . . . 37 G. S. Rice 15Oscar Weiss38 Oscar Weiss15G. S. Rice37, 42 P. B. Bucky21R. D. Hoffman42, 43 P. H. Bird 21, 26, 28R. D. Hall 42 M. K. Hubbert26R. H. Cromwell42 G. Wheeler 26. J. Shenon 42 B. F. Tillson26, 28P. B. Bucky42, 44 T. T. Read 27B. F. Tillson 42, 44 A. B. Yates 43, 44 3. How Can Rock Bursts Be Prevented? . 30P. H. Bird 43 Jack Spalding. . . . • . • • • • . 306. General Discussion . A. B. Yates and P. J. Shenon. . . . 31Jack Spalding44 A. F. Robertson32R. D. Parker49 W. R. Crane 35C. Baring Horwood 51 G. S. Rice 35P. B. Bucky 52] FOREWORD THIS symposium brings together points of view, experiences and ideas on rock bursts from a goodly portion of the globe. Some conceptions, particularly those regarding the necessity of depth, have been fairly well shattered, as we find that they are present in the water tunnels of New York, on the surface at marble quarries in Vermont, and in the coal mines of the United States, as well as in the deep mines of the South African and Kolar gold fields, and in the nickel, copper and gold mines of Canada. Their occurrence under such a variety of conditions is, therefore, a challenge,

Jan 1, 1942

By H. J. de Haan, J. van Lookeren

In view of their size and favorable characteristics, Shell's heavy-oil fields on the eastern coast of Lake Maracaibo, Venezuela — known as the "Bolivar Coast" — are obvious candidates for the application of thermal recovery methods. During the last decade various methods have been tested, such as steam drive,', steam soak and in-situ combustion.3 Steam soak was discovered as a promising production method rather accidentally in 1969, during early steam drive testing in the Mene Grande Tar Sands1 When steam erupted at the surface due to breakdown of the overburden, the injection wells were back-flowed to relieve the reservoir pressure. This resulted in high oil production rates, all the more impressive because the reservoir is unproducible by primary means. It was concluded that injection of limited amounts of steam might be a very effective method for stimulation of heavy-oil wells. To obtain information that would be more widely applicable, testing of the process was continued in the eastern part of the Tia Juana field (Fig. 1). Here even more favorable results were obtained than in Mene Grande. This created sufficient confidence to prompt a large-scale project, which was considered essential for an adequate evaluation of ultimate recovery, steam requirements, mechanical problems and economic prospects. To obtain an early answer on the ultimate recovery a fairly depleted area was selected in the western part of the same field ("A" in Fig. 1). The first steam was injected in March, 1964. This paper describes the performance until the end of 1966. The production mechanism and well inflow performance are discussed in some detail. In view of the favorable results obtained so far, steam soak operations have expanded considerably since the start of this project. Presently, five other projects are under way, of which two are about the same size as the one under discussion, with further extensions being programmed. Description of the Project Reservoir Data Shell's part of the Main Tia Juana reservoir has a proven area of 8,800 acres and an average net oil sand thickness of 130 ft. It contained an initial quantity of 2,750 million bbl of stock tank oil (STOIIP), with an API gravity ranging from 10 to 15 API and a viscosity of 100 to 10,000 cp (at 122F). As a geological unit it is known locally as the Lower Lagun-illas member of the Lagunillas formation, which is early Miocene in age. The sand bodies are believed to be distributary channel sands deposited in a lower coastal plain. Most of the channel sands have lateral and some vertical communication. The field was developed mainly in the period from 1936 to 1950. The ultimate primary recovery is estimated at 18.1 percent of STOIIP, of which 12.5 percent STOIIP had been produced by the end of 1963 from some 540 wells. By then the average pressure had decreased from an initial value of 960 to 550

Jan 1, 1970

By H. T. Kennedy, S. M. Avasthi

An equation developed for gaseous hydrocarbon mixtures predicts molal volumes with an average absolute deviation of 0.73 percent when applied to 264 natural gas and condensate systems including 2,043 PVT points. Another equation developed for liquid hydrocarbon mixtures predicts molal volumes with an average absolute deviation of 1.12 percent when applied to 346 crude oil systems including 1,759 PVT points. Both equations require composition of the mixture to be expressed as mole fraction of methane through heptanes-plus, hydrogen sulfide, nitrogen and carbon dioxide, together with the characteristics of the heptanes-plus fraction in addition to the temperature and pressure. The equations cover wide ranges of the variables involved, and their accuracy is considerably better than that of other available methods. The equations were differentiated to allow calculation of the coefficients of isothermal compressibility and isobaric thermal expansion. (In this paper the coefficient of isothermal com-pressibility and the coefficient of isobaric thermal expansion will be expressed as compressibility and thermal expansion coefficient, respectively.) Equations to calculate these quantities are presented. INTRODUCTION Calculations of reservoir performance for petroleum reservoirs require accurate knowledge of the volumetric behavior of hydrocarbon mixtures, both liquid and gaseous. Compressibilities are required in transient fluid flow problems, and thermal expansion coefficients are important in thermal methods of production. An accurate laboratory investigation of the PVT behavior of each reservoir fluid encountered would be costly and time consuming. For this reason various correlations for predicting fluid properties have been developed and recorded in recent literature. Correlations have been presented in the form of graphs, tables and equations. Since an increasing number of studies are being conducted with the aid of electronic computers, recent efforts have been directed toward development of correla-tions suitable for computer programming. Application of computers permits the use of more complex correlations which otherwise are not feasible. Moreover, methods for predicting reservoir performance, particularly those based on the compositional material balance, depend upon the capability of accurately expressing the molal volumes and other fluid properties as functions of pressure, temperature and composition. The coefficient of isothermal compressibility c is defined by

Jan 1, 1969

By K. P. Gupta, P. C. Panigrahy

The stabilization of the R, a-Mn, and 0-Mn phases have been studied in the Mn-Ti-Fe and Mn-Ti-Co systems. Iron and cobalt both appear to stabilize the (Mn-Ti) R phase to almost the sarne extent. The R-phase region was found to extend from the lowest e/a to slightly beyond the maximunz e/a limit known for this phase. But, while iron appears to stabilize the a-Mn phase, cobalt tends to stabilize the p-Mn phase. In the two systems manganese appears to get replaced by iron and cobalt in each of the mentioned phases. The instability of the a-Mn phase in the Mn-Ti-Co system and the /3 -Mn phase in the Mn-Ti-Fe system cannot be explained on the basis of adverse size effects because atomic diameters for both iron and cobalt (C.N. 12 at. diam) are ziery similnr and not much different from manganese which they replace. Qualitatively, the reason for the stability of the a-Mn and the p-Mn phases can be traced to the more favorable e/a ratio prevailing in the respective systems and to a competing tendency between the two phases. In transition metal alloy systems the o, p,P, R, a- Mn,' and p-Mn2 phases have been claimed as electron compounds. A large volume of work has been done to establish the criterion for the formation of the o phase but until very recently practically no systematic work was done on the a-Mn and the /3-Mn phases. A recent investigation on the P-Mn phase3 indicates the e/a criterion for p-Mn phase stabilization. Since the R phase was first known to appear only in certain ternary systems1 no detailed work was then possible for this phase. The R phase has been recently discovered as a binary intermetallic compound in the Mn-Ti~ and Mn-si~-' binary systems. The existence of binary R phases opens up the possibilities of studying the effect of alloying elements on the stabilization of the R phase. Of the two binary systems possessing an R phase, the Mn-Ti system appears to be more interesting because at a suitable high temperature it is possible to find the three electron compounds, the a-Mn, p-Mn, and R phases, side by side and it is possible to study the effect of a third transition element on these three electron compounds. For the present investigation iron and cobalt, so called B elements for the formation of electron compounds, have been used as the third element to study the stabilization of the a-Mn, P-Mn, and R phases. EXPERIMENTAL PROCEDURE The alloys were prepared by using 99.9 pct pure electrolytic Fe and Mn, 99.5 pct Co, and crystal bar titanium, supplied by Semi Elements Inc., New York and Gallard Schelsinger Mfg. Co., New York. Weighed amounts of the components were melted in recrystal-lized alumina crucibles in an inert atmosphere (argon) high-frequency induction melting unit. Titanium was made into fine chips for easy dissolution and a special charging procedure was adopted to avoid contacts of titanium chips with the alumina crucibles. Up to 20 at. pct Ti, the maximum titanium content in the investigated alloys, there was no visible sign of reaction of titanium with the alumina crucibles. With a careful control of melting time and temperature the losses were minimized and were always found to be below 0.1 pct. Because of such small and almost constant weight losses, the alloys were not finally analyzed. The alloys were wrapped in molybdenum foil and annealed in evacuated and sealed silica capsules at 1000" * 2°C for 72 hr and subsequently quenched in cold tap water. Annealed samples were examined metallographically and by X-ray diffraction. For all high manganese alloys oxalic acid solutions of various concentrations and 1.0 pct HN03 solution were found suitable as etching reagents. Best contrast between the a-Mn and the R phases could be obtained by using freshly prepared 60 pct glycerine + 20 pct HN03 + 20 pct HF solution. For high iron and cobalt containing alloys, especially for alloys containing the a-Fe, y-Fe, and P-Co phases, 15 cc HNOJ + 60 cc HC1 + 15 cc acetic acid + 15 cc water solution was found to be the best etching reagent. All X-ray diffraction work was carried out (using specimens prepared from annealed powders) with a 114.6 mm diam Debye-Scherrer camera using unfiltered FeK radiation at 25 kv and 10 ma. All calculations for X-ray diffraction work were carried out using an IBM 7044 digital computer RESULTS AND DISCUSSION The two ternary systems, MnTiFe and MnTiCo, were investigated near the manganese rich end, Figs. 1 and 2, and show some common features. In both alloy systems large extensions of narrow R phase regions occur at almost constant titanium contents. At titanium contents higher than that of the single phase R-phase alloys, the same unidentified X phase was found in both ternary systems. The extensions of the X phase close to the Mn-Ti binary indicate that this phase could be the TiMns phase. Too few X phase diffraction lines were present in the diffraction patterns to make positive identification of the X phase. In contrast to this similarity the two systems show opposite behavior in the extensions of the a-Mn and 8-Mn phase regions; while iron tends to stabilize the a-Mn phase, cobalt

Jan 1, 1970

By S. D. Thompson

An AIME transaction by P.L. Allsman (1960), "Analysis of Explosive Action in Breaking Rock," contains many useful concepts applicable to blast design. Of special interest was the derivation of a heave blasting burden formula, which is important in establishing the maximum burden. Unfortunately, its derivation contains a fundamental error and then a compensating one. This formula was: [bImpulse _P d At max =nwuwu where: bmax = maximum burden in m (ft). P= average detonation pressure in N/m2 (lb per ft2). A= duration of the average detonation pressure in sec. n= 3.1416. w= specific weight of rock in N/m3 (lb per ft3). u= minimum velocity that must be imparted to the rock in m/sec (ft per sec). d= borehole diameter in m (ft).] The derivation used the impulse-momentum principle, with a 0.3 m thick (1 ft thick) radius of rock mass being acted on by an explosive impulse. However, the rock weight was not converted to mass by dividing by the gravitational constant. This mistake can be verified by checking the units in the formula, which resolve into m1/2-sec instead of meters. Adding the gravitational constant corrects this: [P d Atbmax =gu g = gravitational constant equal to 9.81 m/sect (32.2 ft per sec2).] If the minimum velocity is now taken as 0.3 m/sec (1 ft per sec), as was recommended, excessively large burdens result. Any appropriate rock velocity should be capable of throwing the rock mass a minimum distance so that the swell needed for breakage can occur. Unless the burden is extremely small and the bench height is very high, it is unlikely that a velocity of only 0.3 m/sec (1 ft per sec) will be sufficient. A review of the literature indicates that average rock velocities observed by camera studies typically range from 15 to 30 m/sec (50 to 100 ft per sec) (duPont deNemours and Co., 1977; Tansey, 1979). On this basis, a minimum rock velocity of about 15 m/sec (49 ft per sec) would be expected and not 0.3 m/sec (1 ft per see). When a velocity of 15 m/sec (49 ft per sec) is inserted into the corrected formula, the results approximate those of the original formula with a velocity of 0.3 m/sec (1 ft per sec). The errors were approximately self-compensating [(9 = 1.24)]. ? References Allsman, P.L., 1960, "Analysis of Explosive Action in Breaking Rock," Transactions, AIME, Vol. 217, pp. 475-476. E. I. duPont deNemours and Co., 1977, Blasters' Handbook, 175th Anniversary Edition, Dupont, Wilmington, DE, pp. 233. Tansey, D.O., 1979, "The DuPont Sequential Blasting System," CIM Bulletin, Vol. 72, July, p. 80. Thompson, S.D., 1981, "Critical Review and Revision of Surface Blasting Practice," MS thesis, West Virginia University, pp. 308-316.

Jan 1, 1986

By P. Ramachandrarao, T. R. Anantharaman

EVER since the technique of quenching metals and alloys from the melt (splat cooling) was perfected a decade ago, it has been recognized that the grain size of products solidified by this technique may be extremely small.' The further observation that fcc metals quenched from the liquid state contain very few dislocations has led to the inference2 that metals are subjected to negligible or no stresses during the rapid solidification characteristic of the "gun" or "piston-and-anvil" technique. Evidence for the incidence of appreciable densities of stacking faults has, however, been obtained in case of some splat-cooled fcc and hcp alloys,3 although not for pure metals. In the light of these earlier observations it was considered desirable to study X-ray line-broadening effects, if any, in fcc metals rapidly cooled from the melt. In the present work pure silver (>99.99 pct), aluminum (>99.99 pct) and lead (>99.9 pct) were quenched from the liquid state from temperatures about 50°C above the melting point by the "gun technique" and the resulting foils were subjected to X-ray examination in a Philips Diffractometer. The quenched foils (up to -10 u thick) did not generally stick to the substrate surface and could be easily transferred to the Diffractometer without introducing any plastic deformation. The profiles of the first five reflections from the foils were recorded in each case with Cu Ka, radiation at the slowest available scanning speed of 1/8 deg per min. To correct for instrumental broadening, profiles were also recorded from the metals annealed in vacuo at suitable temperatures. The integral breadths of the X-ray reflections were arrived at by a procedure described earlier.' There was a distinct suggestion of preferred orientation in the recorded intensities of reflections from aluminum and lead foils. Such an effect was not observed in case of silver. In addition, the integral breadths of X-ray reflections from splat-cooled aluminum and lead were not significantly different from those recorded for the annealed metals. The analysis was therefore continued only for silver where the X-ray line broadening was appreciable. The pure diffraction broadening, B, was evaluated for each X-ray reflection (hkl) from silver from the observed, B, and instrumental, b, breadths with the aid of each of the three equations due to Scherrer,5 Anantharaman and Christian,6 and Warren and Biscoe,7 respectively: Bs= B-b BAC=B- b2/B Table I gives the values of particle size, 71, the lattice strain, E, arrived at by the use of the following well-known relations and on the assumption that all observed diffraction broadening could be attributed to lattice strain or particle size, respectively: E = 1/4 cos ? n= B cos ? where A is the wavelength of X-radiation and 0 is the Bragg angle. As no significant peak shifts or asymmetry could be detected in the profiles from the foils, the possibility of any significant contribution due to twins or stacking faults was ruled out. The absence of faults is by no means surprising since pure silver is known to develop stacking faults only on severe deformation and the stacking fault densities recorded so far for even silver filings have been extremely low.' The very low values for percentage mean deviation from the mean value for the particle size in Table I strongly suggest that all observed broadening in splat-cooled silver can be attributed only to small particle size. This conclusion receives further support from the lowest mean deviation recorded for data computed from the Scherrer equation based on Cauchy profiles that are considered characteristic of particle size broadening. Further analysis for separation of particle size and lattice strain effects was considered unnecessary in view of the very large mean deviations obtained for strain values and also the earlier results suggesting absence of even detectable strain in metals and alloys quenched from the melt. It is to be stressed in this connection that the particles are actually grains and not cells formed by walls of high dislocation density usually encountered in deformed samples. As such, the absence of strains is not surprising. The present results are probably the first to record X-ray line broadening due only to small particle

Jan 1, 1970

By C. S. Roberts

THE advent of a sensitive X-ray method of analysis recently has allowed the determination of retained austenite in amounts as low as 0.3 pct.' As a result this phase has been found in quenched low carbon steels where its presence has not been generally suspected. In the course of a study of the tempering process,' retained austenite determinations were made by the X-ray method on a series of high purity Fe-C alloys and plain carbon steels. The chemical analyses of these materials and details of the hardening procedure are given in Table I. Results were obtained after quenching to 72°F (22°C) and — 321 °F (—196°C). Austenitizing temperatures were between 100" and 150°F above A, or Acm. All proeutec-toid cementite or ferrite was in solution. The combination of the results with those of Averbach, Castleman, and Cohen,' and earlier results of Esser

Jan 1, 1954

By Fred D. Wright, Philip B. Bucky

FOREWORD By E. D. Gardner[$] THE present known petroleum reserves are limited, and unless important new fields are discovered the Nation will be dependent, in the not too distant future, upon imports or upon synthetic liquid fuels to supplement domestic petroleum supplies. As a national defense measure, it would appear desirable to develop a substitute source of liquid fuels within the borders of the country if new discoveries of petroleum should prove disappointing. Congress undoubtedly had this in mind when it passed the Synthetic Liquid Fuels Act (78th Congress, approved April 5, 1944). The act directed the Bureau of Mines to construct and operate demonstration plants for producing synthetic liquid fuels from coal and oil shale, and from forestry and agricultural products. As a part of this program, the Bureau of Mines has built a demonstration plant at Anvil Points, near Rifle, Colo., for retorting the oil shale, and has developed a mine to supply the plant with oil shale. At the beginning of mining operations, the physical qualities of the oil shale, which would have a bearing upon the selection of mining methods and practices for exploiting the deposits, were largely unknown. A comprehensive mining-research program has been set up to determine the best methods and practices to follow to obtain the lowest overall practicable mining cost for producing the oil shale on a large scale. Unusually low mining costs will be necessary for shale oil to be produced commercially. Consideration now is being given to exploiting a series of flat-lying beds 70 ft thick by a room-and-pillar method of three benches with the advance heading at the top. This report is one of a series giving the results obtained in research on mining problems. INTRODUCTION The structure and physical qualities of the oil shale indicate that the 70-ft interval of the oil-shale measure can be safely mined in open stopes; studies indicate that this method would be the most economical one to use.1 As labor will be a major item of expense, the largest equipment that could be operated efficiently in the workings would be required to obtain the lowest practicable mining cost. It was therefore desirable to know the maximum safe span of unsupported rooms and the size of pillars necessary to support the overburden. This paper describes the work done at the Columbia School of Mines Barodynamic Laboratory in determining the maximum safe unsupported roof spans and the minimum safe pillar dimensions for the oil-shale mine at Rifle, Colo.

Jan 1, 1947

By K. K. Landes

The north central and northeastern states supply over 50 pct of the chemical and metallurgical limestone produced annually in the United States, and Ontario is the leading source of this material in Canada. About three fourths of the chemical and metallurgical stone produced in this area comes from Michigan, Pennsylvania, Ohio, and Ontario. The specifications, physical and especially chemical, for chemical and metallurgical stone depend upon the end use, but in general the tolerance for impurities is so low as to rule out most limestones and dolomites. Both high calcium limestone and dolomite are used in the metallurgical and chemical industries. The principal metallurgical use is as a flux in iron ore blast furnaces and open hearth steel furnaces. The major chemical uses are in lime burning and soda-ash manufacture. Other important uses include glass manufacture, in making calcium carbide, and in sugar factories. All deposits of high quality carbonate rock are definitely finite. Invariably and inevitably they diminish in either thickness or quality laterally so as to become unworkable as chemical and metallurgical stone. The size of these high quality lenses ranges from a few thousands of tons to hundreds of millions of tons. The best hunting for new supplies is in the geologic formations known to contain premium quality deposits. However, because of high transportation costs, carbonate rocks, to be workable, must be close to market, dollarwise. Definitions: Chemical stone is limestone or dolomite used as a raw material by the chemical industry. The major chemical uses are in lime burning and soda-ash manufacture. Other important uses include glass manufacture, making calcium carbide, and in sugar factories. The specifications for chemical stone depend entirely upon the end product. Some uses require dolomite, some require high calcium limestone; in a few instances, notably in lime burning, either type of carbonate rock can be used as raw material. As a general rule, a fairly pure stone is necessary and for certain particular uses the tolerance for some elements such as sulfur, iron, and phosphorus may be extremely small. Metallurgical stone is used as a flux in furnace operations, especially in the blast furnace where iron ore is converted into pig iron and in the open hearth furnace where pig iron is made into steel. Either limestone or dolomite can be used in the blast furnace, but only high calcium stone is charged in the open hearth (except for rice-size dolomite used as a refractory). There are no rigid chemical specifications for blast furnace stone, but low silica, alumina, sulfur, and phosphorus are desirable. For open hearth use, in addition to low magnesia, a very low sulfur content is also specified by many furnace operators. For furnace use, fluxstone also must be sufficiently shatter resistant that it will remain in lump form during transport and charging into the furnace. Commercial stone is the term applied in the trade for crushed stone used for roadstone and in concrete aggregate. Many of our best chemical and metallurgical limestones are too soft to qualify in the Los Angeles abrasion test for use as commercial stone. However, some limestones, and a higher proportion of dolomites, do qualify for commercial stone and so can be sold to either market. Place Value: Even the highest grade limestone is still a bulk commodity with a relatively low value per ton. As a matter of fact there is very little difference in the average price per ton between high grade chemical and metallurgical stone and crushed limestone used commercially. Most high quality stone is produced in large operations with consequent low cost per ton whereas most commercial stone is produced in relatively small local quarries. As in the case of other bulk commodities most limestone buyers pay more for transporting the raw material than the cost of the stone at its source. For this reason steel furnaces and chemical plants

Jan 1, 1961

By N. R. Morrow, C. C. Harris

The experimental points which describe capillary pressure curves are determined at apparent equilibria which are observed after bydrodynamic flow has ceased. For most systems, the time required to obtain equalization of pressure throughout the discontinuous part of a phase is prohibitive. To permit experimental points to be described as equilibria, a model of capillary behavior is proposed where mass transfer is restricted to bulk fluid flow. Model capillary pressure curves follow if the path described by such points is independent of the rate at which the saturation was changed to attain a capillary pressure point. Aemodified suction potential technique is used to study cyclic relationships between capillary pressure and moisture content for a porous mass. The time taken to complete an experiment was greatly reduced by using small samples. INTRODUCTION Capillary retention of liquid by porous materials has been investigated in the fields of hydrology,l soil science,2 oil reservoir engineering,3 chemical engineering," soil mechanics,5 textiles: paper making: and building materials In studies of the immiscible displacement of one fluid by another within a porous bed, drainage columnsl and suction potential techniques2 have been used to obtain relationships between pressure deficiency and saturation (Fig. 1). Except where there is no hysteresis of contact angle and the solid is of simple geometry, such as a tube of uniform cross section, there is hysteresis in the relationship between capillary pressure and saturation.2 The relationship which has received most attention is displacement of fluid from an initially saturated bed (Fig. 1, Curve R2), the final condition being an irreducible minimum fluid saturation Swr. Imbibition (Fig. 1, Curve A), further desaturation (Fig. 1, Curve R), and intermediate scanning curves have been studied to a lesser but increasing extent.2 ,3,9-12 This paper first considers the nature of the experimental points tracing the capillary pressure curves with respect to the modes and rates of mass transfer which are operative during the course of measurement. There are clear indications that the experimental points which describe these curves are obtained at apparent equilibria which are observed when viscous fluid flow has ceased; and any further changes in the fluid distribution are the result of much slower mass transfer processes, such as diffusion. Unless stated otherwise, this discussion applies to a stable packing of equal, smooth, hydrophilic spheres supported by a suction plate5 with water as the wetting phase and air as the nonwetting phase. The discussion can also be applied, in many

Jan 1, 1966

By L. E. Young

GERMANY'S recent collapse and the occupation by the Allies of the coal fields of the Ruhr, the Saar, Silesia, Poland, and Czechoslovakia have focused attention on the postwar coal problems of Europe. American coal operators are interested deeply in what is happening in Britain, particularly in the discussion of plans to rehabilitate and reorganize the entire British coal mining industry, as such reorganization will probably determine the place Britain will occupy in the European coal markets for the next few decades. The continuing decline of British out-ut per man-shift, particularly during wartime, has resulted in a most serious effort to determine whether this unfortunate trend is due to the physical condition of the coal seams, poor management, poor engineering and planning, inadequate use of power and machinery, or failure of labor to co-operate with management.

Jan 1, 1945

By F. C. Bond

B. H. Bergstrom (Allis-Chalmers Mfg. Co., Milwaukee)—In reading this article, it was difficult to follow through the example given as a starting point in the derivation of the theoretical equation which relates ball size to feed size. A discussion with F. C. Bond led to the following clarification: Bond postulates that "the breaking force exerted by a ball varies ... as the cube of its diameter . . ." and that the force in pounds per square inch required to break a particle varies ... as its diameter squared." He concludes: "It follows that when a l-in. ball breaks a 1-mm particle, a 2-in. ball will break a 4-mm particle, and a 3-in. ball a 9-mm particle." The above example can be true only for a different set of assumptions. Since the first assumption is apparently true, it is the second that must be revised. The second assumption should read that the breaking force required to break a particle varies as its diameter to the 3/2 power. This relationship was derived in the next paragraph of the article.

Jan 1, 1960