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By P. S. Miller, S. H. Ash

EXTENSIVE and diversified resources justify large populations and great industries. To carry on the business of commerce and meet the demands of large populations, the utilization of tunnels in some form for transportation purposes constitutes an important link in modern civilization. The driving of tunnels has been appropriated by the tunneling branch of the heavy-construction industry, and the progressive steps taken by modern tunnel builders were not even dreamed of 50 years ago. Great strides have been made toward more rapid progress in tunneling in the United States during the past 10 years. Tunneling consists of a definite cycle of operations developed from ideas that are crystallized and translated into action programs through various engineering phases that begin with the first preliminary survey and do not end until the job is completed. Once the line of the bore is established and a time set for the completion of the work, the face must advance according to estimates prepared before the work commences. This schedule must be followed in regular sequence from the moment the drills start against a new face of rock until they are ready again to drill the succeeding face, constituting a round.1 Mining is largely tunneling carried on under conditions often more inherently hazardous than actual tunnel construction, but for various reasons1 tunneling is more hazardous than mining in any branch of the mineral industry, On the other hand, obstacles are sometimes encountered in heavy-construction tunneling projects that when met in mining enterprises do not offer comparable tasks to avoid or overcome them. One of these is the existence of water under high pressures. In mining enterprises, various alternatives offer a solution in driving a tunnel, even to the extent of its discontinuance or the abandonment of the mine, but a "construction" tunnel usually must go forward because some important project depends largely if not entirely upon it. This paper describes an unusual method of driving a water-supply tunnel through rock carrying water under pressures and conditions that did not permit the use of ordinary tunneling methods. THE DELAWARE AQUEDUCT The new Delaware aqueduct is a Manhattan project of some magnitude; when completed, it will contain what probably will be, for some time to come, the longest tunnel in the world. Various features in its construction are currently described in the trade journals of the construction industry, and informative engineering details are given in the Delaware Water Supply News, published twice a month by the Board of Water Supply of the City of New York. Work was begun on this project on March 24, 1937. The tunnel will convey water from reservoirs at the headwaters of the Delaware River to the City of New York.

Jan 1, 1942

By Ancel St. John

During a session on coal and coke at the February, 1926, meeting of the American Institute of Mining and Metallurgical Engineers, the writer called attention to the important work on the X-ray analysis of coal1,2 being carried on in England by C. Norman Kemp and his associates. This aroused so much interest that a paper on the subject was requested for the October meeting. It has seemed advisable to make this paper a preliminary survey of the present status in the application of X-ray methods to coal problems and to follow it from time to time with further articles as the art develops. A survey of this sort naturally divides itself into two parts, radio-scopic analysis of the distribution of constituents through the body of the coal, and diffraction analysis of the state of association of the elementary components. In this article the subject matter concerning radioscopic analysis has been drawn almost entirely from the writings of Kemp and his associates and the illustrations have been sptcially furnished by him. It is a pleasure to record here a great indebtedness for this courtesy and cooperation. The subject matter and illustrations concerning diffraction analysis are taken from the author's unpublished researches. Nature and Properties of X-rays Before proceeding it is well to recall the nature and some of the properties of X-rays, as well as our present conception of atomic structure According to the accepted theory atoms are composed of electrically-charged particles. A positively-charged center, called the nucleus,

Jan 1, 1927

By R. B. Schluter, M. M. Fine

A process for winning copper from pelletized chalcocite concentrate without matte smelting and converting is under development at the Twin Cities Metallurgy Research Center of the U.S. Bureau of Mines. The new procedure includes a two-stage fluid-bed treatment in which the pelletized concentrate with 33% Cu and 7% S is first desulfurized to about 0.5% S in an oxidizing atmosphere, and then metallized by reduction with hydrogen. The reduced product is melted with flux to separate metallic copper from the gangue. The metal must be refined to remove residual sulfur and iron. The pelletizing of the fine concentrate into mini-pellets prior to fluid-bed treatment is an important feature of the process, because it permits shorter reaction time, decreases dusting, and facilitates subsequent processing.

Jan 1, 1972

By EL HANAF

The exploratory program initiated in Egypt in 1937 by four major oil companies was well under way early in 1939. Extensive gravity-meter surveys were carried out in the Sinai Peninsula and the Eastern and Western Deserts. Seismic and magnetometer work vas conducted on a restricted scale. The data collected justified wildcat drilling on structures located geophysically and/or geologically.

Jan 1, 1946

By D. Geoffry Minnes, Ray Blair, Stanley J. LeFond

Nepheline syenite is a silica deficient crystal-line rock consisting of albite and microcline feldspars and nepheline, together with varying but small amounts of mafic silicates and other accessory minerals. Nepheline-bearing rocks are widely distributed around the world but only in Canada, Norway, the Union of Soviet Socialist Republics, and the United States are deposits worked commercially, Because of its low melting point and fluxing ability, nepheline syenite was investigated in the early 1900s by many students of glass and ceramics. Although the nepheline syenite deposits in Methuen Township, Ont., Canada, were discovered as early as 1897 it wasn't until 1935 that the first mill was erected to produce nepheline syenite products. In Canada, nepheline syenite deposits are worked by Indusmin Ltd. and International Minerals and Chemical Corp. (Canada) Ltd. who have combined production capacity in excess of 1800 stpd. Between 1935 and 1972 seven million tons valued at $78 million were produced from the Methuen Township deposits. In Norway, the Norsk Nefelin Div. of Elkem Spigerverket has produced nepheline syenite from a deposit on Stjernöy Island in western Finland since early 1960. Production has increased from 8 kt in 1961 to over 200 kt in 1980. Nepheline syenite has been under investigation in the Union of Soviet Socialist Republics (USSR) since at least 1928. In 1951 the first commercial alumina works was brought on stream at Volkhov, near Leningrad, utilizing nepheline concentrates from the Kola peninsula as mill feed. Since then two others have been completed and more are planned. Large quantities of portland cement, sodium carbonate, and potassium carbonate are produced in conjunction with the alumina. A material called nepheline syenite, but actually a pulaskite, is produced in Pulaski County, Arkansas, by the McGeorge Construction Co. for construction aggregates and by the 3M Co. for roofing granules. The Dome Fill Co. purchases the fines and uses them in the preparation of enclosed construction fill. Production is over 2,000,000 stpy. Chap. 16 on "Feldspar, Nepheline Syenite, and Aplite" in the 3rd ed. of Industrial Minerals and Rocks (Castle and Gillson, 1960) and Nepheline Syenite Deposits of Southern Ontario (Hewitt, 1960) contain excellent accounts of earlier commercial development of nepheline syenite as a glass and ceramic material. As in the 4th ed., this chapter deals mostly with the period since 1960 and with matters not previously reported in detail. An English monograph on Nepheline-Syenite and Phonolite (Allen et al., 1968) is a complete survey, at the time, of nepheline syenite which, with its very complete list of references, is an excellent source book. End Uses Nepheline syenite from the Canadian and Norwegian producers finds use primarily in the manufacture of glass and ceramics. One producer also makes several grades of nephellne syenite that are useful as extender pigments and fillers in paint, plastics, and rubber. In the Soviet Union nepheline is used in increasing quantities in the manufacture of alumina, alkali carbonates, and portland cement and to a lesser degree it is used in the manufacture of colored container glass.

Jan 1, 1983

By Clarence Zener

Contents Page General Principles................................................................. 551 Equilibrium Diagrams......................................................... 551 Nucleation................................................................... 553 Kinetics of Phase-boundary Propagation......................................... 553 Kinetics of Growth of New Phase............................................... 556 Spheroidization............................................................... 560 Pure Iron-carbon System........................................................... 561 Formation of Pearlite.......................................................... 561 Interlamellar Spacing........................................................ 562 Pearlite C-curve............................................................. 563 Bainite Formation............................................................. 565 Formation of Martensite....................................................... 570 Loss of Tetragonality of Martensite.............................................. 570 Effect of Alloys upon Decomposition of Austenite..................................... 572 Pearlite...................................................................... 572 Bainite and Martensite......................................................... 574 Time-temperature-transformation Curves............................................. 576 Appendix A............................................................. ......... 579 Appendix B....................................................................... 580 Appendix C....................................................................... 580 The present investigation started in an attempt to understand certain details of the decomposition of austenite, and of the effect of alloying elements thereon. As the investigation proceeded it became apparent that not only these details, but all the general features of austenite decomposition, could be understood in terms of fundamental physical principles. Since the direct applicability of these physical principles has not been previously recognized, it was decided to incorporate the original results of the investigation into a review of the general subject of the kinetics of austenite decomposition. This review constitutes the present article. An extended summary of the results is given on pages 576 to 579. This article, which deals with the kinetics of phase transformations, may appropriately be considered as a sequel to two recent articles1,2 from this laboratory on the equilibrium relations in medium alloy steels.

Jan 1, 1947

By Clarence Zener

Contents Page General Principles................................................................. 551 Equilibrium Diagrams......................................................... 551 Nucleation................................................................... 553 Kinetics of Phase-boundary Propagation......................................... 553 Kinetics of Growth of New Phase............................................... 556 Spheroidization............................................................... 560 Pure Iron-carbon System........................................................... 561 Formation of Pearlite.......................................................... 561 Interlamellar Spacing........................................................ 562 Pearlite C-curve............................................................. 563 Bainite Formation............................................................. 565 Formation of Martensite....................................................... 570 Loss of Tetragonality of Martensite.............................................. 570 Effect of Alloys upon Decomposition of Austenite..................................... 572 Pearlite...................................................................... 572 Bainite and Martensite......................................................... 574 Time-temperature-transformation Curves............................................. 576 Appendix A............................................................. ......... 579 Appendix B....................................................................... 580 Appendix C....................................................................... 580 The present investigation started in an attempt to understand certain details of the decomposition of austenite, and of the effect of alloying elements thereon. As the investigation proceeded it became apparent that not only these details, but all the general features of austenite decomposition, could be understood in terms of fundamental physical principles. Since the direct applicability of these physical principles has not been previously recognized, it was decided to incorporate the original results of the investigation into a review of the general subject of the kinetics of austenite decomposition. This review constitutes the present article. An extended summary of the results is given on pages 576 to 579. This article, which deals with the kinetics of phase transformations, may appropriately be considered as a sequel to two recent articles1,2 from this laboratory on the equilibrium relations in medium alloy steels.

Jan 1, 1947

By James M. Stapleton

It has long been recognized by blastfurnace men that correct top distribution of materials is very important in efficient and economical furnace operation. Thousands of experiments on top design, filling, sizing, and other operations have been carried out to improving furnace performance by securing uniform distribution. Many of these experiments have worked out satisfactorily and have been passed along to the industry. Many of them have been discarded and forgotten. It has been the custom to judge the results of such experimentation by the results shown in improved or lowered furnace efficiency. While the effect on furnace practice will have to continue to be the final criterion of experimental changes, it has always been a desire of blast-furnace men to ascertain the reason for failure or success. Efficiency in the blast furnace approaching the maximum can be measured in several ways: (1) by actual operating results as revealed in the coke rate and tonnage figures, and (2), in the degree to which the top gas approaches the limiting ratio of CO/CO2 for the reduction of iron oxide by CO gas. This ratio is shown in the equilibrium curve in Fig. I for the system Fe-O-C and CO2-CO-C. The closer the top gases approach this limiting ratio (set at 1.08 by Martin1 because of the effect of limestone calcination) the more efficiently we may expect a furnace to operate. The fact that low CO/CO2 ratios parallel eficient operating performance caused us to investigate the cause of good or poor distribution and the effect of filling and other changes on furnace operation. Heretofore it has been possible to take a sample of furnace gas (usually from the dust catcher) and from it determine how closely the reducing gases were to the ideal or limiting value as set by the equilibrium diagram. However, to find just where in the top area the distribution was distorted and the top-gas CO/CO2 ratios were distant from equilibrium values has been a difficult and expensive investigational procedure. In an effort to overcome this difficulty, apparatus was designed to take gas samples and temperatures across the top radius of the furnace. It was hoped that with the aid of this apparatus traverse sampling of the ascending gases could be simplified, and the cost of sampling substantially lowered. Routine experimenting could then be maintained and results checked with furnace operation. It must be emphasized that a traverse sampling is necessary for a true picture, as single samples at any one point are unreliable. This statement can be verified by an examination of Tables 3 to 6, showing results obtained at our furnaces in a large number of tests. Apparatus The design of the equipment for taking the samples was governed by the need for providing a simple, routine test that could be performed fairly quickly without adversely affecting normal furnace operation.

Jan 1, 1943

By James M. Stapleton

It has long been recognized by blastfurnace men that correct top distribution of materials is very important in efficient and economical furnace operation. Thousands of experiments on top design, filling, sizing, and other operations have been carried out to improving furnace performance by securing uniform distribution. Many of these experiments have worked out satisfactorily and have been passed along to the industry. Many of them have been discarded and forgotten. It has been the custom to judge the results of such experimentation by the results shown in improved or lowered furnace efficiency. While the effect on furnace practice will have to continue to be the final criterion of experimental changes, it has always been a desire of blast-furnace men to ascertain the reason for failure or success. Efficiency in the blast furnace approaching the maximum can be measured in several ways: (1) by actual operating results as revealed in the coke rate and tonnage figures, and (2), in the degree to which the top gas approaches the limiting ratio of CO/CO2 for the reduction of iron oxide by CO gas. This ratio is shown in the equilibrium curve in Fig. I for the system Fe-O-C and CO2-CO-C. The closer the top gases approach this limiting ratio (set at 1.08 by Martin1 because of the effect of limestone calcination) the more efficiently we may expect a furnace to operate. The fact that low CO/CO2 ratios parallel eficient operating performance caused us to investigate the cause of good or poor distribution and the effect of filling and other changes on furnace operation. Heretofore it has been possible to take a sample of furnace gas (usually from the dust catcher) and from it determine how closely the reducing gases were to the ideal or limiting value as set by the equilibrium diagram. However, to find just where in the top area the distribution was distorted and the top-gas CO/CO2 ratios were distant from equilibrium values has been a difficult and expensive investigational procedure. In an effort to overcome this difficulty, apparatus was designed to take gas samples and temperatures across the top radius of the furnace. It was hoped that with the aid of this apparatus traverse sampling of the ascending gases could be simplified, and the cost of sampling substantially lowered. Routine experimenting could then be maintained and results checked with furnace operation. It must be emphasized that a traverse sampling is necessary for a true picture, as single samples at any one point are unreliable. This statement can be verified by an examination of Tables 3 to 6, showing results obtained at our furnaces in a large number of tests. Apparatus The design of the equipment for taking the samples was governed by the need for providing a simple, routine test that could be performed fairly quickly without adversely affecting normal furnace operation.

Jan 1, 1943

By Hugh Henton

THIS paper is the result of an investigation made in association with Dr. Charles H. Fulton. Early in 1918 a search was started for methods of utilizing, in the manufacture of basic refractories, certain domestic resources in magnesites, dolomites, and magnesian limestones. Much information was collected during that year and during 1919 regarding magnesite and dolomite deposits. During 1920 and 1921 a research was made into methods of calcining dolomite and separating magnesia therefrom. Some success was attained and many new ideas were brought out in connection with the preparation and utilization of magnesia in the form of "caustic" or light-burned material as well as in the form of refractory or "dead-burned" material. Stimulated by this success, much advance has been made in manufacturing processes for the "plastic magnesia," so called, used for magnesia cement, stucco, flooring and otherwise in the structural industries.

Jan 3, 1926

By T. Egleston

The necessity of using a refractory material capable of much greater resistance to chemical action and having a far higher melting-point than those which contain silica, which melt and sweat off in the furnace even when not exposed to bases forming with silica more or less fusible compounds, has led to a careful practical study of all those materials which contain very refractory bases. The results of these researches, extending over several years, and made on a very large scale in many of the largest works in Europe, are of the highest interest, not only considered as a step in the progress of the study of the materials themselves, but in the application of refractory materials to metallurgical uses in general. The result of the experience of the last seven years with these basic materials, as in general with all such substanccs, is that natural products cannot be used as such. They are either too uncertain in their quality, contain substances which may in certain cases be very injurious, or, when in a condition in which they might be used, are so rare as to become practically unavailable for employment on a large scale. The materials that may he used are therefore not only limited in number. but they must be prepared artificially. When the use of basic artificial material is further extended, no doubt the number of these substances will not only be greatly increased, but the methods of preparation will be both perfected and cheapened to such an extent as to permit their application in processes for which they have hitherto proved too expensive. The quantity of refractory materials required for making ingots will he from 130 to 150 Ibs. per ton, or between 6 and 8 per cent. of the metal produced. In an establishment producing 2000 to 3000 tons of steel per week, considerable space is required to handle the basic materials properly. It is proposed in this paper to briefly discuss these basic materials and their application in the only two metallurgical processes where they have as yet been applied. These are the basic Bessemer and the basic open-hearth process, known as the Thomas-Gilchrist processes.

Jan 1, 1886

By G. A. Reinhardt, Albert Sauveur

Although many metallurgists know that some pearlitic special steels can be made troostitic, martensitic, and even austenitic, without quenching, and, therefore, without exposing them to the dangers of the quenching-bath, the practical significance of such possibility does not seem to have received the attention it deserves. Let us recall briefly the mechanism of the transformation alluded to. In Fig. 1 (after Guillet) is shown the constitutional diagram of nickel-steel; that is, of alloys of iron, carbon, and nickel. Any steel the composition of which falls within the area LPO is pearlitic after slow cooling; any steel the composition of which is represented by a point within the area MLO is martensitic, and any steel within the area MNO is austenitic. Starting with pearlitic steel, then by increasing the carbon-content or the nickel-content, or both, the metal becomes marten-sitic and eventually austenitic; that is, its composition crosses first the boundary-line LO and then the line MO—and it remains martensitic or austenitic after slow (air) cooling.' We have in this way imparted to the metal without quenching it the properties of hardened carbon-steel. In other words, the steel is now self-hardening; Nickel cannot be introduced into solid steel, but by the well-known process of case-hardening it

Jan 1, 1913

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

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

Jan 1, 1966

By R. G. Brown

Tars paper will present a general description of the different mineral belts in the Butte City region (limited, however, to the copper and contiguous silver veins) such as may serve to give an intelligent idea of the distribution and characteristics of the deposits, forming thus a groundwork of information, which it is hoped will have value, when later writers enter into particularized detail.

Jan 1, 1895

By Franklyn Oatman

IN order that the conditions which obtain in an oil well may be readily understood, a brief description of a typical California well and. a number of the phenomena accompanying same will be given. That the necessity for the exclusion of water be realized, the effects of water intrusion, a description of methods of prevention, and a discussion of causes of failure will be presented, followed by a summary and recommendations. Fig. 1 shows a section of a typical well which illustrates the relation of oil sands to overlying strata. It indicates a deep water sand separated from the oil sand by shale, and the proper place for the final shutting off of water. In this well a comparatively thick stratum of compact shale protected the oil from overlying water so that the operation of landing the water string was a simple matter. In some wells the protecting stratum may be only from 3 to 5 ft. thick and very careful operation is necessary in order to land the water string of casing properly and not puncture through to the oil sand. The cases just cited are common, but occasionally, after excluding overlying water, productive oil sands are drilled through in the expectation of finding more productive underlying sand, and a water-bearing stratum is tapped. In this case the problem is the reverse of the normal; water must be prevented from ascending rather than descending. A discussion of well-drilling methods is not within the scope of this paper, except such operations as pertain to shutting off of water. A brief outline of the several conditions which may accompany drilling follows. Some or all may be present in any particular case. The direct relation of these to prevention of intrusion will he discussed in detail further on. In drilling, the hole. becomes more or less irregular in shape, and rough, and as the casing follows the bit into the well it does not fit snugly against the walls. As a result, water may descend between the casing and walls of the well. If a circulation pump is not used during drilling, the hole is simply punched through and the pulverized material removed from the well by means of a bailer. If circulation is maintained there is a continual flow of water down inside the casing and up around the outside between the pipe and the walls of hole. This keeps an open. space around the pipe.

Jan 3, 1914

By C. R. Austin

In a recent paper1 the authors presented information on a refinement of the Rohn type of creep test with data on pure iron that exemplified the behavior of the apparatus. The present paper extends that work to nickel and cobalt and to the examination of the comparative high-temperature properties of two widely used commercial alloys. Careful attention has been given to the effect of plastic deformation in decreasing creep rate, using the elementary metals iron, nickel and cobalt for purposes of analysis. In any endeavor to develop new materials for high-temperature service one soon encounters a real problem as to the sort of test to be employed in evaluating the commercial possibilities of the alloys. At one time it was considered satisfactory to determine the tensile strengths at elevated temperatures and to use these values as a criterion for the commercial application of the alloys. More recently the proportional limit has been used as a means of classification. Data obtained from a form of bend test have also shown promise as providing a "merit index" of high-temperature serviceability.= Koerber and Pomp3 state that since the influence of testing time is small, the high-temperature yield point of steel furnishes sufficiently reliable and concordant values up to about 350" C. (and a maximum of 450" C. for alloy steels) to serve as a suitable basis for comparison evaluations of materials and for judging permissible stresses. Koerber and Pomp consider, however, that above these temperatures creep limit must be substituted for the high-temperature yield point as the all-important characteristic of the material. Whatever may be their definition of

Jan 1, 1934

By A. A. Bauer, F. A. Rough, G. H. Beatty

AS a result of recent studies, the constitution of the zirconium-uranium system has been fairly well defined. A diagram for the system is shown in Fig. 1. However, both oxygen and nitrogen are known1-3 to have a pronounced effect on the limits of both ß- and e -phase regions. It has been shown that small amounts of oxygen severely constrict the compositional limits of these phase regions in the ternary zirconium-uranium-oxygen system. A previously published tentative diagram shown in Fig. 2 illustrates the ß-phase constriction resulting from oxygen additions. Generally, iodide zirconium has been used in constitutional studies of zirconium-uranium alloys. While this is the highest purity material available, cast iodide zirconium-uranium alloys will generally average from 200 to 300 ppm 0 and from 50 to 60 ppm N. Thus, while the constitution of the zirconium-uranium system is fairly well defined, it must be realized that this definition applies to alloys containing in the vicinity of 250 ppm 0 and 50 ppm N. The present investigation was undertaken to accurately determine the boundary between the ß-plus-P and ß phases at a single temperature in the binary zirconium-uranium system by quantitatively

Jan 1, 1959

By W. O. Philbrook, R. H. Spitzer, F. S. Manning

A generalized mathematical model has been developed to describe the kinetics of the gaseous, topo-chemical reduction of porous hematite spheres. Gas-solid reduction is permitted at each of three advancing interfaces and is controlled by a complex series-parallel sequence of chemical and transport steps. Despite the fact that transport resistances are significant to the advance of each interface, little deviation from linear advance is predicted for the first 98 pct of reduction. Calculations to predict the movement of magnetite /wustite interface by a solid-state diffusion mechanism have been incorporated into the earlier dense-pellet model.' The porous-pellet model is found to give a better description than the dense-pellet one for McKewan's measurements2 of interface movements in dense polycrystalline hematite reduced in hydrogen-water vapor mixtures. THIS paper reports a continuation of work"3" directed toward the better understanding of gas-solid reactions and the development of mathematical models that may be helpful in the design or control of ore-reduction processes. Laboratory studies of the reduction of single oxide samples in tube furnaces normally employ an abundant excess of pure reducing gas. Reduction may appear to be adequately described by a model assuming gas-solid reaction solely at the iron/wustite interface.''' However, when iron ore is reduced in either a fixed bed or an efficiently operated counter-current column, there are portions of the bed where the partially spent gas is no longer capable of reducing wustite to iron. Nevertheless, the formation of the intermediate reaction products, wustite or magnetite, can and does continue. In order to account for this aspect of the reduction of beds of particles, three semiempirical mathematical models were devised.' One of these was for the limiting case of completely dense particles, and two alternatives were provided for porous particles. For purposes of the analysis, a dense pellet was defined as one in which the wustite and magnetite layers were impervious to the reducing gas when the atmosphere was capable of forming iron. In a porous pellet, the intermediate product layers were assumed to be sufficiently permeable to allow reducing gas to penetrate beyond the iron/wustite interface to form wustite and magnetite by removal of oxygen as a gaseous product rather than by a solid-state redfiction mechanism. Further progress required a better understanding of the reaction of the individual particles with the gas stream. A comprehensive mathematical treatment was developed' to describe the continually changing interplay of transport and reaction steps

Jan 1, 1967

By Sherwin Kelly

IN presenting this brief historical perspective, it is not my purpose to address myself to the geophysicists, to most of whom the story is already well known. My objective is to draw the attention of those who hold the belief that geophysics is something new, typically twentieth century, to the fact that fundamentally, whether it was known by the name of geo-physics or not, the science is an ancient and an honorable one. It began many centuries ago, and our modern civilization and its commerce owe a great debt to its founders, who today are likely to he overlooked and their names forgotten. The word "geophysics" means the physics of the earth, and is descriptive of a science that in many ways bears the same relationship to geology that astrophysics does to astronomy. When dealing with dis-tant stars or deeply buried rocks, the experimenter cannot reach them to obtain samples, which can be taken to his laboratory for study. He therefore exhibits the resourcefulness of Mahomet in the mountain episode, and makes the terrestrial globe or the cosmic universe his labora-tory, studying the effects of distant bodies on certain "fields of force"" which come to him across interstellar space, or through the rocks that make our earth. The application of these techniques of the physics laboratory to the study of the stars is the science of astrophysics, and to the investigation of the earth is geophysics. Yet the origin of the most valuable contribution to the world's trade and commerce ever made by geophysics remains lost in deep obscurity. Unknown even is the country wherein lived the unsung genius who invented the first geophysical instrument, the mariner's compass! Worse yet, it is not certain whether this invaluable guide of man had its begin-nings in Europe or in Asia. A Chinese legend tells of the Emperor Hwang-ti, who attacked his enemy Tchi-yeou on the plains of Tchou-lou in the year 2634 B.C., whereupon the latter magically raised such a fog that the Emperor could not pursue the retreating troops. Not to be outdone, the mighty ruler constructed a chariot that indicated the cardi-

Jan 1, 1938

By A. M. Turkalo

IT is a well-known fact that martensitic steels show a greater resistance to brittle fracture than do pearlitic and bainitic steels. It was, therefore, thought worthwhile to investigate the mode of brittle fracture with respect to structure by studying the effect of various austenite decomposition products on the propagation of brittle fracture in steel by means of electron microscopy. Newly developed replication techniques together with the advantages of the electron microscope such as great depth of field, available high magnification and easy adaptation to stereophotography make electron microscopy very suitable for fracture studies. EXPERIMENTAL PROCEDURE An essentially plain carbon steel containing 0.56 pct C, 1.30 pct Mn, 0.02 pct P, 0.03 pct S and 0.22 pct Si was used in this investigation. The following table gives the heat treatments used to obtain the various austenite decomposition products: The resulting austenite grain size from the 870°C austenitization treatment was about an ASTM No. 7 grain size. The specimens which were 2 in. long, 1/4-in. diam bars were austenitized in a tube furnace through which argon gas was blown. The tube was not, however, air-free and the specimens were not completely oxide-free. Isothermal treatments were done in a lead bath. With the exception of the fully hardened specimen and the one as-isothermally transformed at 300°C the heat treated specimens were notched in the following fashion with a jeweler's saw. A cut about 0.08 in. deep was made perpendicular to the length of the bar. The specimen then was rotated about 45 deg and another cut about 0.08 in. deep was made. In the case of the hard martensitic and bainitic specimens, only one cut was made and the depth was not controlled. The design of the two-cut notch caused fracture to initiate at the point of intersection of the two saw cuts. The specimens were broken at -196°C in a Charpy impact testing machine. In order to hold the specimens securely in the impact machine two square pieces of mild steel were made about 5/8 in. long having the same cross section as that of a standard Charpy specimen but containing a hole 1/4 in. diam through the center of the cross-section. These adapters were slipped over the ends of the test specimen which was then secured tightly by means of set screws in the adapters. The specimen with the adapters was cooled to -196°C in liquid N,, then placed in the impact machine and broken within 3 sec. One half of the broken specimen was used for the electron microscope study of the actual fracture surface. The other half was nickel-plated and a cross section through the notch and fracture was polished for electron microscope examination. Carbon replicas of the fracture specimens for the electron microscope study were made essentially according to Bradley's evaporation technique.' Both direct carbon and two-stage carbon replication techniques were used. In the case of the direct carbon technique, a thin layer of carbon was evaporated first at an angle of about 45 deg to the mean fracture surface and then another film of carbon was evaporated normally to the fracture surface. The carbon replica was freed electrolytically.2 The specimen was made an anode in a 10 pct Nital polishing solution. It was etched intermittently by shutting off the power now and then. The freed replica was washed in 40 to 50 pct water solution of nitric acid for 10 min or so, then washed in water and picked up on a screen for examination. The two-stage carbon replication technique involved first making a primary replica of cellulose * acetate from which a carbon replica was then made. One side of a strip of cellulose acetate wet with acetone was pressed lightly against the surface of the specimen, allowed to dry and then stripped. Prior to the deposition of carbon, which was done at 90 deg to the cellulose acetate replica surface, chromium was evaporated at 45 deg. After the carbon evaporation the cellulose acetate was dissolved in acetone according to the Jaffe method3 leaving the carbon replica preshadowed with chromium for examination.

Jan 1, 1961