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By Kent A. Pease

Design methods for foundation anchors and sockets constructed in rock are based largely on empirical correlations which yield a reasonable estimate for initial capacity, but do not address the general concerns of failure mode and load-displacement behavior. This paper focuses on the behavior of foundation-rock interfaces and shows that interface behavior under increasing load results in a progression from an elastic response to secondary behavior, in which interface failure occurs, and finally to a residual stage at large deformations. Procedures to follow this progression are outlined to provide a more fundamental understanding of the problem.

Jan 1, 1984

By W. N. Best

This paper is not intended as a scientific discussion of the combustion of oil but is written from the standpoint of an operator who has the experience and qualifications necessary to guide others in producing the most economical results in the use of liquid fuels. Oil, in this paper, usually means petroleum or its products but incidental reference is made to other liquid and gaseous fuels, so that the term may be considered as referring to all liquid and gaseous hydrocarbons in comparison with solid fuels, as coal and wood. However, only a few of the principal factors in the use of oil as a fuel can be given. The present, and prospective, high price of coal is causing users of fuel to renew inquiry as to the merits of other forms of fuel for industrial purposes. Crude oil (petroleum) is proving to be one of the world's most valuable mineral resources. The recent discovery that oil underlies a considerable area of the United States, Mexico, and other parts of the world to a greater extent than was formerly believed and the large production of some of the wells in these areas shows the probable quantity of fuel oil that may now be available. Through the energy of Lord Cowdrey, who was one of the pioneers of the oil industry in Mexico, oil has been discovered in England; some prominent geologists believe that it may be found in quantity in Great Britain. For years, oil has been known to be of great value in the manufneture of metals. It has proved incomparable in forge shops, steel foundries, heat-treating furnaces, and wherever accuracy of temperatures is essential, or where a maximum output is desired as well as quality of metal. In some types of equipment, the output produced with oil as fuel is double that obtained with coal and at a reduction of 50 per cent. in the cost of the fuel. For example, in drop-forging plants, the metal is always waiting for the man when oil is used as fuel, whereas with coal, the man must wait for the metal to become sufficiently heated. It has only been since January, 1919, that the oil supply could be relied on for boiler service, owing to the war conditions and the inability to get oil tankers for the delivery of the oil from Mexico to Atlantic ports; but now a constant supply is assured, and many manufacturers are installing it in their power plants. The cost varies with the size of the

Jan 1, 1921

By R. S. Christie

Reservoir pressure is the pressure at which a fluid is held in a state of equilibrium in a porous stratum. This pressure may be a result of the genesis of oil or gas and its subsequent migration into and through an adjacent porous stratum, or of hydraulic head. Reservoir pressure is an indication of the potential energy contained in the reservoir, and when it is known the engineer is in a position to use it to advantage in recovering and lifting the oil. It is important to know the pressures in any type of reservoir, but this knowledge is probably of greater value in a limestone reservoir, as at Hobbs, where producing rates or conditions may be more sensitive to changes in pressures. The Hobbs field is in east central Lea County, New Mexico. The discovery well was completed by the Midwest Refining C I. in 1928, but intensive development did not begin until after the completion by the Humble Oil and Refining Co. of No. 1-A Bowers in February, 1930. There are 143 producing wells on approximately 5500 acres. The field has not been defined to the northwest, but a projection of structural contours indicates that the productive area ultimately may cover 7500 acres. The producing horizon is the White or Crystalline lime of Permian age. The top of the lime is found at an average depth of 4000 ft. and the wells penetrate it an average distance of 200 ft. The main pay zone is an oolitic stratum about 25 ft. below the top, and varies from 2 to 15 ft. in thickness. Other porous or cavernous strata are found lower in the lime but have little saturation. The initial production varied from 100 to 25,000 bbl. per day, depending perhaps to some extent on the structural location but chiefly on the porosity of the pay. The initial gas-oil ratio varied from 325 to 16,000 cu. ft. per barrel. In wells where the top of the White lime was found below 350 ft. below sea level (Fig. 1)) the gas-oil ratio was usually less than 1500 cu. ft. per barrel, while in wells higher than 350 ft. below sea level, the ratio was usually above 2000 cu. ft. per barrel. The water table has been determined at about 620 ft. below sea level, by three wells on the west side of the field. With few exceptions, the wells have been completed with 7-in. casing cemented

Jan 1, 1932

By Herbert H. Uhlig

A STUDY of passivity in chromium-iron alloys holds considerable interest, both because of the present-day practical importance of the stainless steels, and because of the scientific importance attached to the mechanism of their corrosion resistance. Upon the discovery of the passive chromium-iron alloys in 1912, it seemed logical to attribute the observed phenomenal corrosion resistance to a thin, continuous, protective reaction product on the surface. The product was thought to be Cr2O3 or a similar oxide containing both chromium and iron. This mechanism seemed likely in view of Michael Faraday's conjecture that passive iron is not reactive in concentrated nitric acid because of an oxide on the metal surface.† Since 1912, data have accumulated that permit a further exploration into the nature of passivity and provide a new approach to the problem. A summary of the facts lends considerable weight to a mechanism based not on physical protection of an oxide or similar compound, although such compounds may be present on the surface, but to a change in tendency of surface metal atoms to react chemically. This change in reaction tendency is ascribed to chemisorbed films that effectively satisfy residual valence forces of the metal surface, but do not appreciably disturb the positions of metal atoms in the lattice. In other words, formation of a new lattice such as that of an oxide is not a necessary condition for this type of passivity. The decreased reaction tendency of the metal by reason of chemisorbed films can thereby account for low reaction rates of the stainless steels in many media, as well as a noble galvanic potential as is observed. Substances capable of adsorbing on the stainless steels, and hence accompanying the property of passivity, are typically oxygen, nitrites or chromates, but are not in any sense limited to these. Other elements and compounds can also chemisorb, and therefore may also play a major part in the mechanism of passivity in specific media. The mechanism of passivity based on chemisorption or activated adsorption begins with the interpretation Langmuir proposed for his experiments concerning adsorbed oxygen on tungsten.1 He found that adsorbed oxygen was tightly bound, remaining on the tungsten surface above temperatures at which WO3 rapidly volatilizes. The oxygen in such a state did not readily react with hydrogen even at

Jan 1, 1947

J. R. Lane (Metals Research Laboratory, Washington)—A new type of deformation called "kinking" has recently been described. Is there any relation between the "rumpling" described in this paper and "kinking?" D. C. Jillson (author's reply)—Both are manifestations of bending about [210] axis. The difference is one of degree. W. C. Ellis (Bell Telephone Laboratories, New York) —Some observations of deformation in zinc recorded in this paper may be applicable generally to flow in metals. One of these, deformation in torsion without evidence of slip or twinning in the early stages and with startling ease, when the twist is about the hexagonal axis, adds another method of flow to the presently increasing list of mechanisms. This illustrates again that a crystal will utilize any realizable process to flow and relieve stress. The process is not necessarily classical directional slip—& this case, it is rotational slip. The question naturally occurs: Will face-centered cubic metas stressed by twisting about an octahedral axis flow in a similar manner by rotation on an octahedral plane? I would like to ask Dr. Jillson if he has made any experiments or knows of any experiments of this type on face-centered cubic metals? Face-centered cubic metals possibly would behave differently from zinc, since, for one thing, the stacking sequence is different for the two structures. The results of such experiments, however, would be instructive in providing more information about deformation processes. D. C. Jillson—Dr. Roy E. Swift, working in the Hammond Laboratory at Yale, performed a twist test on a single crystal of brass. The work has not been published, and I do not know the crystallographic direction of the axis of the specimen used. Lo-ching Chang (Columbia University, New York)— Observations similar to Figs. 1 and 2 of the paper were obtained by us during the bending and unbending of an orthorhombic Au-Cd alloy.'l This orthorhombic alloy is the product of diffusionless transformation from a single crystal of p Au-Cd alloy (CsC1 structure) containing 47.5 atomic pct Cd on cooling to about 60 "C.62 Referring to the effects of annealing, has the author tried any loilg time high temperature anneal, such as 150 to 200 hr at 40O°C? D. C. Jillson—No. C. Crussard (Ecole des Mines, Paris: France)—I

Jan 1, 1952

By C.H. Davis, W.H. Bassett

The ease and value of the application of spectrum analysis to industrial chemistry appears to be appreciated in few of the large works laboratories of this country. For 8 years, this analysis has been of great value to the authors in both analytical and metallurgical work. To the analyst the complete qualitative analysis of an unknown alloy, revealed by a spectrogram, is a sure basis for the planning of the most direct and rapid method of attack. As the determination of each element proceeds, the purity of precipitates may be checked as often as desired. The spectrograph proves invaluable in the recognition of impurities, the separation of which would entail a lengthy and difficult procedure, or when the weight of an unknown is less than is necessary to complete the desired determinations. A few hundredths of a gram will usually suffice for spectrographic analysis. In the separation of the rarer elements, the spectrograph will show, with precision, the point where each step has been successful. In zinc of certain classes, indium, gallium, and germanium have been isolated in this way; the presence of antimony in lake coppers has been proved; and bismuth has been detected in zinc and in alloys where the presence of a few thousandths of a per cent. would be harmful. An antimony precipitate in a delicate determination may contain a considerable proportion of tin or arsenic, both of which will be revealed. The spectrograph is consequently important to the metallurgist as well as to the analyst. Impurities in raw material are often a source of annoyance, especially when their detection involves delay and costly analytical work. Whethcr low conductivity in copper is due to arsenic, nickel, or something else may be cluickly found out. Residual traces of boron, magnesium, manganese, silicon, vanadium, and other deoxidizing agents are easily identified where wet analysis may fail to reveal their presence, even after days of effort. Complex alloys of any kind are dissociated by the spectro-

Jan 1, 1923

By W. H. Bassett, C. H. Davis

The ease and value of the application of spectrum analysis to industrial chemistry appears to be appreciated in few of the large works laboratories of this country. For 8 years, this analysis has been of great value to the authors in both analytical and metallurgical work. To the analyst the complete qualitative analysis of an unknown alloy, revealed by a spectrogram, is a sure basis for the planning of the most direct and rapid method of attack. As the determination of each element proceeds, the purity of precipitates may be checked as often as desired. The spectrograph proves invaluable in the recognition of impurities, the separation of which would entail a lengthy and difficult procedure, or when the weight of an unknown is less than is necessary to complete the desired determinations. A few hundredths of a gram will usually suffice for spectrographic analysis. In the separation of the rarer elements, the spectrograph will show, with precision, the point where each step has been successful. In zinc of certain classes, indium, gallium, and germanium have been isolated in this way; the presence of antimony in lake coppers has been proved; and bismuth has been detected in zinc and in alloys where the presence of a few thousandths of a per cent. would be harmful. An antimony precipitate in a delicate determination may contain a considerable proportion of tin or arsenic, both of which will be revealed. The spectrograph is consequently important to the metallurgist as well as to the analyst. Impurities in raw material are often a source of annoyance, especially when their detection involves delay and costly analytical work. Whethcr low conductivity in copper is due to arsenic, nickel, or something else may be cluickly found out. Residual traces of boron, magnesium, manganese, silicon, vanadium, and other deoxidizing agents are easily identified where wet analysis may fail to reveal their presence, even after days of effort. Complex alloys of any kind are dissociated by the spectro-

Jan 1, 1923

By Willis H. Carrier

PARTICULAR interest in the ventilation of deep mines, especially those in South Africa, has been created by a very complete system of cooling of the world's deepest mine, the Turf shaft of the Robinson Deep in Johannesburg. The writer visited this mine in January, 1936, and again in 1937. During these visits and subsequently, a considerable part of the theory involved in rock cooling in tunnels was developed and this has been checked by practical observations of the rates of rock cooling made within mines. The purpose of this paper is to set forth the method of attack of the mine problem. The cooling or air conditioning of mines by the use of mechanical refrigeration was not wholly new 1-5 when the Robinson Deep installation was made. The first mine to be cooled was the Morro Velho mine, in Brazil. The first installation in this mine was put into operation in December 1920, the refrigerant being ammonia.5 The surface cooling gave considerable benefit but it proved inadequate as greater depths were reached, therefore in 1929 two centrifugal refrigerating machines were installed at the 6000-ft. level. These were used in conjunction with the surface cooling system to furnish additional cooling at the lower levels. This later installation used Carrene as a refrigerant. This nonflammable refrigerant, having a boiling point of 104º at sea level, insured reasonable safety, since all parts of the machine operated at subatmospheric pressure. Very favorable reports have been received on the effectiveness of this installation, but no recent data are available. An interesting feature of that plant is that the condenser water is cooled by spraying it into the exhaust air from the mine at the base of the ventilation upcast, which permits the water to be cooled within a few degrees of the wet-bulb temperature of the air entering the upcast, and the only water that has to be supplied for condensing purposes is that lost by evaporation, or about 0.5 per cent of the volume circulating through the condenser. This plan affords an ideal means for the removal of the heat load from the refrigerating system, and of course also from the mine itself. In many mines, however, especially those in South Africa, there is no

Jan 1, 1938

By H. L. Hartman

The estimation of the magnitude of pressure changes which occur in mine ventilation circuits is of primary importance to the mining engineer in making changes in an existing mine or in projecting the ventilation requirements of a new mine. It is a formidable task in many cases, because no adequate theory is available and empirical data are unreliable or even lacking. The common practice of increasing one's estimate of the mine static pressure by an arbitrary "safety factor" to compensate for the unknown is a poor substitute for accuracy. Generally little difficulty is encountered in calculating friction losses in mine airways. As long as the friction factor can be reliably estimated, the well-known Atkinson formula gives accurate results. However, it is in the determination of shock losses that the ventilation engineer encounters difficulty and is apt to resort to an arbitrary allowance. Shock losses may constitute as little as five or as much as twenty-five percent or more of the overall pressure drop in the mine, and such allowances are generally completely unsatisfactory. Since other shock losses have been covered by McElroy (1), this paper deals with a long-neglected source of shock and pressure change in ventilation circuits, divergence and convergence of airflows, here referred to by their more common mining terms, splits and junctions. PREVIOUS WORK There is practically no fundamental information available in ventilation literature on the splitting and junction of airflows, either in mining or mechanical engineering periodicals or handbooks. Fluid mechanics textbooks seemingly avoid the subject of divergence and convergence, except for brief empirical treatment. The only investigation reported for mine ventilation systems was by Weeks, et a1 (21), in 1933. Although applicable to the case of line brattices in coal mines, it cannot be applied to the general case of mine splitting and junctions involving change of direction with little or no area change. In dealing briefly with the subject of shock losses at splits and junctions, McElroy (1) suggests only that they be considered comparable to bends, with losses at junctions being increased 50 pct to allow for interference of merging streams. He recognizes the importance of quantity ratio but concludes that exact quantitative data are lacking to compute losses at splits and junctions. A very capable summary and analysis of the state of knowledge in industrial ventilation and fluid mechanics regarding losses due to divergence has recently been reported by Gilman (3). In considering all earlier work dealing with both air and water as fluids, he compares results on a common basis and obtains good empirical agreement. For divergent flow, the controlling variable in each branch is the quantity ratio, although the deflection angle is of secondary importance. Empirical equations are presented for straight and 90-deg branches with varying velocity ratios, assuming branches smaller than the main duct. These formulas are modifications of the Borda equation for abrupt contraction and expansion. The only information available on shock losses in convergent flow are approximate experimental data presented by Alden (4) and the Manual of Recommended Practice for Industrial Ventilation of the American Conference of Governmental Industrial Hygienists. Alden considers the effects of both quantity ratio and deflection angle. The data indicate an effect opposite to that observed in divergence, the shock loss varying directly with quantity ratio. SHOCK LOSS THEORY Because pressure losses due to shock have been found to bear a constant relation to the mean velocity of flow in a given conduit, they are frequently expressed as a dimensionless function of the velocity head, termed the shock loss factor. For airflow in ducts and mine airways, the shock loss may be represented by the formula (1): Hx - XHv, (1)

Jan 1, 1961

By Millard K. Shaler, Sydney H. Ball

During the past 50 years the attention of mining-men has been turned to Africa, and within the past decade prospecting-expeditions sent into Central Africa have resulted in the open-ing-up of several mines. Having recently spent two years in the Belgian Congo for the Societe Internationale Forestiere et Miniere du Congo, it is our purpose to outline briefly the mining-conditions in that part of Central Africa. Before it became, in 1908, a Belgian colony, this region was known as the Congo Free State. 11. Location and Area. The Belgian Congo lies in southwestern Central Africa, west of the continental divide, as illustrated in Fig. 1. It has a coastline of but 20 miles on the Atlantic, but widens rapidly eastward to points 5 north and 14 south of the equator. Its area is 908,000 sq. miles, which is almost one-quarter that of the United States and Alaska, or more than one and one-half times that of Alaska. Stated in other terms, its area is nearly one-third that of the United States, exclusive of Alaska and the insular possessions, or more than that of all the United States east of the Mississippi river. III. Topography and Drainage. From north to south, Africa is made up of three topographic elements: 1, the Atlas mountains, a highly-accentuated region

Jan 1, 1911

By W. H. Andrews

The constantly increasing consumption of Portland cement in the State makes the above subject of particular interest at this time. The increasing demand is due to the rapid settling of the country and the fact that new uses are being found frequently for the above named commercial article. The industry is one that is bound to grow as the population increases, and this being the case it may be well at this time to consider briefly the matter of the chemical and physical composition of proper raw materials. A cement mixture is one that contains approximately 75 per cent, carbonate of lime, 15 per cent. silica, and 5 to 7 per cent. alumina and iron oxides; the other elements being magnesium carbonate and mall quantities of the rarer elements generally associated with limestone deposits. It can be readily seen from the above composition that it is possible to build up this mixture from a number of different materials. First.—A rock high in carbonate of lime can be mixed with clay or shale in such proportions as to bring about the desired composition ; the chief difficulty in the building up of such a mixture is that it is hard to find a clay or shale in which the silica-alumina ratio lies between 4 to 1 and 3 to 1 and at the same time shows physical characteristics which will make certain its adaptability to the practical manufacture of Portland cement. Very often clays or shales are found which are right chemically but contain large quantities of grit or free silica. Such clays or shale must be ground to extreme fineness in the mixture in order to make the silica and alumina combine with the lime when the mixture is burned. On the other hand, clays or hales are often found that have the proper physical characteristics but in which the amount of alumina is too great. Second.—A mixture can be built up of different limestones some of which run above the 75 per cent. requirement and others below;

Jan 1, 1914

By R. G. Treuting, W. C. Ellis

D. Whitwham, M. Mouflard, and P. Lacombe (British Council Research Fellow, Labratoire du Professor Chaudron, Vitry-sur-Seine; Inqenieur de Recherches, Labratoire de Vitry; and Maitre de Recherches, Labratoire de Vitry, Professeur Adjoint de Metallurgie, Ecole des Mines, Paris)—The authors' work is of great interest in bringing out the geometrical relations existing between twinned lattices, and for the notion of a coincidence super lattice developed from this. We should like to point out that a similar idea was put forward by Friedel8 in his book on the subject of lattice merohedrism "merihedrie réticulaire:"—When two crystals A and B are twinned with respect to a mirror plane, there exists a common superlattice, "réseau periode," which is independent of the contact surface between the two crystals. The volume V of this superlattice is a simple multiple of the volume v of the lattice of crystals A, or B, (Fig. 5). This "multiple cell" is defined by the twin plane (p q r) and a row of atoms [h k l] normal to this plane, the base being taken as the smallest unit (two-dimensional) of this plane. Two cases must be considered. First when the multiple cell, as defined, has no atom site at its center nor at the center of its faces other than (p q r), v the twinning index is defined by —. In the second v case, when one of the two above conditions does not v apply, then the twinning index is V 2v A more intuitive definition of the twinning index would be the proportion of atoms of C, which would coincide with those of C1 when the C, lattice is imagined to extend on the other side of the contact surface. In the case of cubic crystals, the twinning index

Jan 1, 1952

By Frederick C. Langenberg

A method is presented for computing the solubility of nitrogen in molten alloy steels. Examples are given to illustrate the procedure, and comparisons are made between predicted and measured nitrogen solubilities. THERE is an increasing use of nitrogen as a major alloying element in steels, or as a partial substitute for other alloying elements. Nitrogen is a potent austenite stabilizer, and Cr-Mn-low Ni-N steels, or even Cr-Mn-N steels, are being considered

Jan 1, 1957

By Edgar Rickard

IT SHOULD be clearly understood that my remarks on economic conditions in Russia are entirely personal, and not official as an officer of the Ameri-can Relief Administration. The American Relief Administration is concerned exclusively in relief operations. The American Relief Administration has played a large part in the conditions as they exist in Russia today and it does not seem to be out of order to give you the high lights of the work accomplished. SIXTY MILLION DOLLARS FOR RUSSIAN RELIEF The Riga Agreement, by which we were enabled to carry on our operations, was signed in Riga on Aug. 20 of last year. On Sept. 8, we opened our first relief station in Petrograd. On Sept. 18, our first food was handed out in Samara on the Volga River, in the center of the so-called famine district. Altogether over 775,000 tons of food have been sent from the Atlantic Coast into Russia and we have moved this entire quantity of food over a dilapidated and wornout system of railways; and we estimate that our loss will be less than one-half of one per cent. in shortages and thefts. We have had available for this Russian work approximately $60,000,000. The bulk of this money was derived from a Congressional grant of $20,000,000 for food stuffs, a further Congressional grant of Army medical surplus supplies of $4,000,000, a grant by the Soviet Government of $11,400,000. This Soviet grant is a rather interesting phase of our operations. In all of Mr. Hoover's relief work abroad he has demanded of the country receiving relief that the people them-selves do something concrete for their own good before he would undertake to collect large sums of money in America. Secondly, before he was willing to go before Congress and ask for funds from our government he desired that the Soviet Government show their good will.

Jan 11, 1922

By D. K. Crampton

INTERNAL stress and season cracking in brass have been studied for many years and the technical literature contains many data on various phases of the subject. A résumé of the literature shows certain fairly well established points upon which various authors are mostly agreed: 1. Season cracking is primarily caused by the presence of relatively high internal stresses, or possibly in some cases by external stresses, or both. 2. A specific corrosion is also essential to season cracking: Certain agents, particularly mercurous salts, mercuric salts and ammonia salts; have such a specific corrosive effect. 3. The tendency to season crack under given conditions increases with increasing zinc content, brass containing less than 20 per cent zinc being relatively immune. 4. In alpha brass the season cracks are intercrystalline; in alphabeta brass they lie between the two constituents; and in beta brass they are transcrystalline. 5. The ordinary impurities or added elements in special brasses have little or no effect on the tendency to season crack. 6. Internal stresses can be eliminated, or at least reduced to a safe 'limit by annealing treatments at temperatures that do not produce visible microstructural changes or appreciable softening of the worked brasses. There are, however, some points in connection with the phenomenon of season cracking which have not been thoroughly investigated, or wherein different authors and investigators are not entirely in agreement. The investigations described in this paper were undertaken to determine: 1. The correlation between mercurous nitrate tests and actual season cracking on long-time atmospheric exposure. 2. The quantitative effect of type and degree of drawing operations on the intensity of internal stress and on the tendency to season crack in brass tubes. 3. The possibility of drawing high-brass tubes in such a manner as to prevent the occurrence of harmful stresses rather than to find a remedy for such stresses once having obtained them.

Jan 1, 1930

By W. H. Smith

IN connection with some recent work on the effect of impurities on the ductility of chromium, it appeared desirable to know the solid solubility of carbon in chromium. A literature survey indicated that this information was not available. Although considerable work has been done on the Cr-C phase diagram,&apos;.&apos; previous investigators have been more concerned with the structure and phase boundaries of the carbide phases than with the terminal solid solution. The phase diagram shown in Fig. 1 is taken from the work of Bloom and Grant&apos; and represents the most recent determination. As indicated by the dashed line, the a solid-solubility limit was not determined. Experimental Procedure Alloys of chromium were prepared from hydrogen-treated and vacuum-degassed electrolytic chromium plus spectrographic grade carbon. The oxygen and nitrogen content of the alloys was <0.002 pct. After melting, analysis of the alloys showed them to contain 0.02, 0.08, 0.15, and 0.55 pct C. Pieces of the alloys were heated in a protective atmosphere to various temperatures and then quenched after holding for a time sufficient to insure equilibrium. Microscopic examination of the as-quenched alloys for the presence of a second phase was used as a measure of the solubility limit. The heats were made in a multiple hearth arc-furnace using a zirconium-gettered static argon atmosphere. A zirconium melt was made before each Cr-C heat. Triple melting was used to insure ingot homogeneity as shown by microscopic examination. The alloys were prepared by adding portions of a 4.5 pct C-Cr master alloy to high purity chromium. The carbon contents listed previously were those obtained by analysis. The nitrogen and oxygen contents after arc melting were both <0.002 pct. Sections 1/8X1/4X1/2 in. were cut from the 100-g ingots and a hole drilled in one end in order to suspend the sample from a molybdenum wire. After the surface was carefully cleaned, a sample of each melt was hung in a mullite tube heated externally by a platinum resistance furnace connected to a vacuum system. The lower portion of the mullite tube was sealed to Pyrex and closed off several inches below the furnace. This was filled with sili-cone oil kept cold by circulating cold water around the outside of the Pyrex. Quenching into the oil bath was achieved by melting a fuse wire supporting the sample. It required about 4 sec for the sample to cool from 1400" to 600°C. This severity of quench was considered satisfactory to freeze-in the high temperature equilibrium. For tests made at temperatures of 900" to 1200°C, heating was done in vacuum; for tests above 1200°C, an argon atmosphere was used. The holding time employed ranged from 12 hr at 900°C to 6 hr at 1400°C. Experiments were performed at temperatures of 900°, 1000°, 1100°, 1200°, 1300°, and 1400°C. Microscopic examination for evidence of a second phase was done at X1500. Experimental Result The microstructures of a 0.08 pct C-Cr alloy as-cast and after quenching from 1300°C are shown in Figs. 2 and 3. A 0.15 pct C-Cr alloy quenched from 1300°C is shown in Fig. 4. The data obtained from the quenching experiments is shown graphically in Fig. 5. If the Van&apos;t Hoff equation is obeyed, a plot on a logarithmic scale of the mol fraction of solute vs the reciprocal of the absolute temperature should give a straight line. For dilute solutions the weight percentage can be substituted for the mol fraction without introducing any appreciable error. The Van&apos;t Hoff equation can then be written as where H is the heat of solution in calories per mol. The slope of the straight line on the log pct C vs 1/T plot gives the value of AH. Assuming that the Van&apos;t Hoff equation is obeyed, which is probably justified for the dilute solution of carbon in chromium, the heavy straight line shown on Fig. 5 represents the best fit of the data. This line was obtained as follows. On Fig. 5 the results of the microscopic examination of all alloys following quenching were plotted and designated as to whether one or two phases were seen. Below 1100°C all alloys showed a second phase on quenching. The heavy vertical lines shown in Fig. 5 therefore represent the possible range of the ter-

Jan 1, 1958

Jan 1, 1928

By Joseph Jenson

Total United States production for 1928 was 900,364,000 bbl. as compared with 901,129,000 for 1927, or 2,466,000 bbl. per day versus 2,468,000. The three major producing areas were Texas, Oklahoma and California. Texas production increased from 217,389,000 bbl. in 1927 to 256,888,000 in 1928—an increase of 39,499,000 bbl. following an increase of 44,500,000 bbl. in 1927. Oklahoma production amounted to 249,558,000 bbl. in 1928 as compared with 277,775,000 bbl. in 1927 and 177,650,000 bbl. in 1926. California production for 1928 was 231,982,000 bbl. as compared with 231,196,000 in 1927. Production increased markedly in Venezuela and declined in Mexico. Elsewhere no great changes or declines in production were noted. New discoveries occurred in nearly all districts. The many excellent reviews of the various districts of the United States presented at this meeting, are each fully summarized and tell their own story so well that little would be gained by attempting to repeat their content here. There are certain impressions to be gathered from these papers and certain trends that are indicated by them which may better be pointed out. OVERPRODUCTION Overproduction is the most serious one of them. Efforts to avert it resulted in a measure of cooperation in the oil industry more widespread in character and more beneficial in results than has ever been recorded in any previous year. These efforts were undertaken in the closing months of 1927 and enthusiastically effected before the spring of 1928 had passed. Unfortunately, slight advances in prices during the summer months accompanied by the letting down of this sort, of effort resulted in a marked increase of production during the latter half of 1928. Successful delay in the drilling of new prospective areas was in effect in Oklahoma. California delayed some drilling and increased its shut-in

Jan 1, 1929

By Harold S. Davis

SURROUNDING the nuclear core of an atomic energy plant there are usually one or more thick walls of concrete, as required to protect instruments and personnel from the harmful effects of nuclear radiations. Sometimes these massive walls are of ordinary concrete weighing about 150 pcf. To reduce wall thicknesses, concrete weighing 200 to 350 pcf may be used. Such high densities are obtained by using natural aggregate processed from heavy ore, or by using steel slugs or iron shot in concrete. Mix data for a number of high-density concretes are summarized in Table I.1 High density at low cost is of prime importance in shields designed to absorb gamma rays. On the other hand, biological shields located near the reactor core must attenuate neutrons as well as gamma rays. In general, a biological shield should contain: 1) heavy elements to slow down high energy neutrons and to absorb gamma rays, 2) either light elements or hydrogenous materials to moderate neutrons of intermediate energy, and 3) materials to absorb neutrons once they have been slowed down to thermal energies. Some shield materials, iron and water for example, are effective in one or more of the above ways. On the other hand, some otherwise excellent shield materials have certain undesirable radiation properties that limit the ways or number of places they can be used. For example, when iron absorbs neutrons it emits secondary gamma rays of high energy. On the other hand, boron absorbs neutrons avidly without producing high energy gamma rays. In spite of its high cost, boron is sometimes used in concrete to minimize production of secondary gamma rays. In some shielding applications it is necessary to avoid materials that become radioactive when subjected to neutron bombardment, continuing to give off high energy gamma rays for long periods after being removed from a neutron field.

Jan 5, 1957

By P. W. Shimer

The purpose of this note is to call attention to a source of error in the determination of graphitic carbon, made by the usual method of solution in hydrochloric acid. Although the method is tedious, because of the necessary treatment of the separated carbon with caustic potassa, alcohol and ether, the text-books seem to give it preference; and it is, perhaps, used more generally than the method of solution in dilute nitric acid. Solution in hydrochloric acid usually gives higher graphitic-carbon results than solution in nitric acid, and many, therefore, consider it more trustworthy, the inference being that the lower results obtained by nitric acid are due to the loss of some of the finely-divided graphite by reason of the oxi-

Jan 1, 1896