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By W. L. Penberthy, H. J. Ramey

Experimental work on the combustion oil recovery process has consisted of both laboratory and field studies. Although field experiments are the ultimate test of any oil recovery process, they are costly, time consuming and difficult to analyze quantitatively. Laboratory combustion tube experiments can be opertzted far more rapidly and cheaply, but are subject to scaling and interpretation problems. This paper points out some important design problems, operational criteria and considerations in2portunt to interpretation of results. An analytical hcut model of movement of a burning front axiully along a cylinder with heat loss through an annular insulation was developed. The result was used to identify steady-state temperatrrre distributions both ahead of and behind the burning front, with and without heat loss. Results indicate potential operating limitations on the minimum burning front rielocity (or air flux) which may be used for any given combustion tube. Results also enable estimating the effective thermal diffusivity and over-all heat loss from experimental data and thickness of the brnning zone. Resu lts of operation of a combustion tube constructed recently verify this preliminary theory in the region immediately ahead of and behind the burning front surprisinRly well. INTRODUCTION Many field and laboratory studies of the forward combustion oil recovery process have been conducted since the early publications of Kuhn and Kochl and Grant and Szasz2 in 1953 and 1954. In view of the complex and costly nature of this type of investigation, it is not surprising that no complete theory of the nature of the forward combustion Drocess is yet available. However, gross effects are understood well enough that reasonable design procedures are available for planning field operations. Nelson and McNeil 3,4 have published two comprehensive papers concerning design procedures. One major consideration in planning field operations is the fuel concentration at the burning front. Fuel concentration controls air requirements — an important cost factor in forward combustion. Although fuel concentration can be estimated from field test results by various methods, results are subject to great uncertainty in view of natural limitations on experimental observations. Nelson and hlcNeil4 recommend that fuel concentration be determined from laboratory combustion tube studies. Fuel concentration is only one of many important factors which can be studied by combustion tube experimentation. An obvious goal of imporrance must be development of a comprehensive theory of the forward combustion process. If a theory of this process can be established which matches controlled laboratory experimentation, it should be possible to apply this theory to field operating conditions with some confidence. Laboratory combustion tube studies have already yielded important information concerning the combustion process. However, details concerning the design, construction and operation of combustion tubes are rare. Combustion tubes used by various investigators vary in size, length and mode of operation. Therefore, one purpose of this paper is to present considerations important to design, construction and operation of a combustion tube. In regard to previous combustion tube studies, attention is called to Refs. 1 through 9. These references describe a wide variety of equipment types and present a great deal of pertinent experimental data. In general, combustion tubes usually consist of thin-walled stainless steel tubes containing an oil sand pack mounted within a pressure jacket. Provisions have often been made to heat the tube ex tern a lly by separately controlled heaters to reduce heat losses. This step usually permits operation at low air fluxes (air rate per square foot burning front surface) similar to those encountered in field operations. Burning is usually conducted from the air inlet end of the tube to the outflow end. The tube orientation used has been vertical or horizontal. For vertical tubes, burning has been conducted vertically downwards. As a result of laboratory studies, many of the

Jan 1, 1967

By Russell C., Fleming

FOK, many years the officials of the Magma Copper Co. mine at Superior, Ariz., have had to contend with adverse conditions underground in the form of high rock temperatures, hot water, and high relative humidity. These conditions in the mine have been such that working the mine would have been impossible were it not for the constantly expanding and improved sys- tem of ventilation to produce bearable conditions in the working places. Results that have already been achieved make an interesting study of what can be done along those lines. From the time the mine was first opened in 1910 it has been hot. An idea of the conditions that have persistently been encountered can be obtained from parts of the mine that are not being worked at present or that do not yet have sufficient ventilation. Virgin rock temperatures as determined in drill holes at the faces range from 104° to 116°*. An observation made at the face of No. 5 West footwall drift on the 2800-ft. level.

Jan 1, 1930

By C. E. Tsoutrelis

A new method for determining rock drillability in diamond drilling is discussed; the method takes into consideration both penetration rate and bit wear. The method is based on drilling a rock specimen under controlled laboratory conditions using a model bit. The technique used for determining the experimental variables is extremely simple, quick, and reliable. Drillability is then determined by the mathematics of drilling. In considering the different factors that affect diamond drilling performance, the nature of the rock to be drilled is of outmost importance since it affects significantly the drilling costs and such other variables as bit type and design, drilling thrust, and bit rotary speed. Many attempts have been made to study this effect by correlating actual drilling performances either to certain physical properties of the rock being drilled1-? or to test drilling data obtained under laboratory conditions.7-13 These attempts were aimed at providing a reliable method of predicting by simple means the expected rock behavior in actual drilling, thus giving the engineer a tool to use in estimating drilling performances and costs in different types of rock. The purpose of this paper is to describe such a method by which rock drillability (a term used in the technical literature to describe rock behavior in drilling) could be determined in diamond drilling. It is believed that the proposed simple and reliable method will cover the need of the mining industry for a workable method of measuring the drillability of rocks. It should be emphasized, however, that since drill-ability depends on the physical properties of rock and each drilling process (diamond, percussive, rotary) is affected by different or partly different rock properties,14-l6 the proposed method of determining rock drillability cannot be extended to the other drilling processes. The results presented in this paper form part of an extensive three-year research program carried out by the author in the laboratories of the Greek Institute of Geology and Subsurface Research. During this period the effects of the physical properties of rocks and of such operational variables as drilling thrust and bit rotary speed in diamond drilling were investigated in detail. DRILLABILITY CONCEPT The literature is not devoid of drillability studies. While there are a number of investigators1,3,5-7,9-0,12-13,17 who have attempted to establish by direct methods (i.e., drilling tests under laboratory conditions) or indirect (i.e., through a physical property of rock) an index from which the drilling performance in a given rock may be estimated, very few6-7,9,12, of the proposed methods seem to be of much practical value to the diamond drilling engineer and none to date has been universally accepted. Commenting on the proposed methods for assessing rock drillability, Fish14 remarks that "for a measure of drillability to be accepted it is essential that penetration rate at a given thrust and bit life are elucidated as otherwise the method is of little value." This statement should be examined in more detail by making use of the penetration rate-drilling time diagram obtained in drilling a rock under constant operational conditions. Furthermore, the merits of using this diagram to describe rock drillability will be pointed out. At the same time reference will be made to this diagram when discussing some previously proposed methods. Fig. 1 illustrates such a diagram for three rocks,A, B, and C, which have been diamond drilled under identical conditions. It is assumed here that rocks A and B have the same initial penetration rate, i.e., VOA = Vog, but since rock B is more abrasive than A, rapid bit wear occurs and as a result the fall of its penetration rate with respect to time is more vigorous than in rock A. This is shown graphically by a steeper V = f(t) (0 curve in this rock than in rock A. Rock C has a lower initial penetration rate, due to higher strength properties16 but since it is not very abrasive, only a slight fall of its penetration rate occurs during drilling (in this category are some limestone and marbles with compressive strength above 1000 kg per sq cm). It follows from the foregoing considerations that the characteristic for each rock curve (I) is a function of (i), the penetration rate of the rock Vo recorded at the instant of commencing drilling, which determines the starting point of the curve (1) on the y-axis and (ii), the abrasive rock properties which determine the rate of fall of Vo with respect to time. Thus, curve (I) provides an actual picture of the rock behavior in drilling for given operational conditions, and it can be used with complete satisfaction to assess rock drillability. It can be seen clearly from Fig. I that proposed methods for assessing rock drillability by measuring the

Jan 1, 1970

By Harlowe Hardinge

AN extensive recent trip throughout the mining districts of the Southwest, Central West, an Northwest,' reveals a numbes of interesting conditions that have influenced operators, in both large and small mills, to modify their flow sheets insofar as they pertain to crushing and grinding. The changes made and planned for the future should be of interest. It is interesting to note when traveling through the country, how ideas change and practice is modified, and it is rather amusing to see how milling methods seem to run, more or less, in cycles. New ideas and developments are brought about which run through the industry and are taken up by many of the best and most well informed operators. Some of them will change, sooner or later, back to their old practice; for, like everything .else, what will work well in one place will not necessarily be suited to another. On the other hand, it is often difficult to establish. other practices known to be of value, owing to the natural resistance to make a change, but on the whole, the western mill men seem to be more alive to possible benefits of various modifications than any other engineers with whom I have come in contact in all parts of the world. Mill men in other parts of the world always keep in con- tact with what is being done in the western part of the United States, but it does not necessarily follow that those in the western part of the United States are always right. Some of these changes that have been made and afterward abandoned will be referred to later.

Jan 1, 1929

PAGE Problems of American Railroads Early in 1936, by J. J. Pelley 3 The Heavier Nonferrous Metals in Transportation, by C. H. Mathewson... 9 Light-weight Metals in the Transportation Industry, by Zay Jeffries 21 Trends in the Metallurgy of Low-alloy, High-yield-strength Structural Steels, by H. W. Gillett 40 Structural Steels and Light-weight Metals in the Transportation Industry, by Horace C. Knerr 62 Proposed Use of Alloys in Merchant Shipbuilding, by Edgar P. Trask 66 Mutual Effects of Metallurgy and Speed in the Automotive Industry, by Merrill C. Horine 84 The Railroads and Light-weight Equipment, by W. W. Colpitts 93

Jan 1, 1936

By W. R. Purcell, C. S. Brooks

The internal surfaces of rocks which are in contact with interstitial fluids are known to influence in some degree the recovery of hydrocarbons from pay zones. Despite the admitted importance of the influence of solid surfaces on hydrocarbon recovery, little information is available concerning the extent of surface of reservoir rocks. In this paper a description is given of the apparatus and procedure employed in the determination of the surface areas of sedimentary rocks, and values are reported for a variety of sandstone and limestone cores. In addition, consideration is given to the Kozeny equation, which relates surface area to porosity and permeability. A colliparison is made between the surface areas as calculated from this equation and the geometrical areas of a series of packs of spherical glass beads. Also, for a group of sandstone cores. Kozeny areas are compared with surface areas as determined by the gas adsorption method employed in this investigation. INTRODUCTION It has long been recognized that many processes which are of importance to hydrocarbon production are controlled in some degree by the extent of the surface of the reservoir rock through which the hydrocarbons move. For example, the recovery efficiency that is obtained in a given reservoir is certainly determined in part by the action of interfacial forces between the reservoir fluids and rock, and this action is influenced in turn by the extent of solid surface. Despite the admitted importance of surface effects to problems of petroleum recovery, little information is available concerning the extent of surface of reservoir rocks." It is the purpose of this paper to describe an apparatus which has been employed for the measurement of the surface areas of rock samples and to present the values which have been obtained for a variety of sandstone and limestone cores. In addition, the relationship of surface area to permeability and porosity, as given by the Kozeny equation, will be discussed. METHOD OF MEASURING SURFACE AREA The method of determining surface areas as employed in this work has previously found wide use in studies of porous solids such as catalysts. The method involves the measurement of the amount of physical adsorption of an inert gas, such as nitrogen or argon, on the bare surface of the solid at reduced pressure and constant temperature near the normal liquefaction temperature of the gas. With the aid of the theory of isothermal adsorption as developed by Brunauer, Emmett, and Teller,' it is possible to ascertain the amount of gas (and hence the number of molecules) which is required to cover the solid surface with a single layer of molecules. From a knowledge of the covering area per molecule the total surface ares of the solid can be computed. Since the Brunauer. Emmett, Teller (BET) theory has been adequately discussed elsewhere: it will suffice here merely to present their final equation as ordinarily employed for surface-area calculations. This equation relates the volume of gas, V, which is adsorbed at pressure, P, to the liquefaction pressure, Po, of the gas, and to the volume of gas, V.,, that is required to form a monomolecular layer: In this equation C is a quantity which is related to the heats of adsorption and liquefaction of the gas; for a particular solid-gas system at Constant temperature, C is considered to have a constant value. The basic adsorption data can be presented in the form of Equation (1) by plotting the quantity P/V(Po- P) as a func-

Jan 1, 1952

By Samuel Daniels

THE Al-Cu-Ni-Mg alloy is much benefited by heat treatment and, in such con¬dition, is preferable to the Al-Cu-Fe-Mg alloy either as cast or as heat-treated, when both are reheated to temperatures of from 400° to 600° F. and compared, cold, with respect to strength and to hardness. The main differences between the alloys do not arise until the reheating temperature exceeds 400° F., above which they gradually soften. This softening is characterized metallographically by the appearance of intragranular precipitate. The Al-Cu-Ni-Mg alloy is weakest and least hard after being reheated at 600° F., the AI-Cu-Fe-Mg alloy at about 700° F. The former starts to reharden at 700° F., the latter at 800° F. There is a tendency for both alloys to lose strength and hardness with prolongation of time at the reheating temperatures of 500° and of 700° F. The Al-Cu-Ni-Mg alloy is considerably stronger and harder than the Al-Cu-Fe-Mg alloy when both are heat-treated and reheated for long periods of time at 500° and 700° F. Although the latter can be made harder initially than the AI-Cu-Ni-Mg alloy by suitable quenching and aging, heat treatment, in general, favors the retention of this initial (strength and) hardness after reheating to a much greater degree in the Al-Cu-Ni-Mg alloy. The percentage of elongation of the two materials in any condition is very small. CERTAIN aluminum alloys have been used for pistons and other parts operating at temperatures up to 650° F. because of their lightness, high thermal conductivity and specific heat, fair strength and hardness at elevated temperatures, excellent machineability, and moderate resistance o corrosion. In the piston, the inertia forces and the bearing loading and with this the vibration are decreased. The piston head functions at a lower temperature (about 200° F. below one of cast iron), so that, because of the lessened tendency toward carbonization and detonation, higher compression ratios may be used. On the other hand, the aluminum alloys do not have the wearing and bearing qualities of cast iron; also they have a large coefficient of expansion, allowance for which must be made in the design.

Jan 2, 1926

By William G. Christy

EFFORTS at smoke abatement date back to the year 1273 in England when a law was passed prohibiting the use of "sea cole." The law was not enforced, so King Edward I, 33 years later, appointed a commission "to enquire of all such who burnt sea cole in the city or parts adjoining, and to punish them for first offense with great fines and ransomes, and for the second offense to demolish their furnaces." Many other commissions have since been named to investigate the smoke problem in England, but it still persists in many British cities. In the United States the movement to abate the smoke nuisance started in certain Middle Western cities, and has made considerable progress. Until recently, the coal-producing industry co-operated little in smoke¬abatement programs, taking the attitude that smoke elimination is the dealer's or user's responsibility; and the dealers, in turn placed the responsibility entirely on the user.

Jan 1, 1942

By F. R. Hensel

Up to the present time few attempts have been made to produce hard nonmagnetic materials by heat treatment of austenitic steels. The usual result has been to cause them to pass into the martensitic stage, thus destroying to a great extent the typical austenitic properties, since this involves a transition of a portion of the iron from a face-centered to a body-centered type of atomic arrangement. High-strength nonmagnetic materials such as might be provided by properly hardening austenite are required in the electrical industry for different machine parts. In Europe nonmagnetic retainer rings for restraining the end-turns of the rotor windings in turbo-alternators have been developed as a special application of high-strength austenite. In testing1 a 28,000-kva. three-phase Siemens turbogenerator running at 3000 r.p.m. at full load current, the losses in the short-circuit test were 450 kw. for the magnetic ring and 286 kw. for the nonmagnetic, and the difference should be attributable to the magnetic ring. The differences in temperatures during the same test are given in Table 1 and these show the advantage of a nonmagnetic over a magnetic retainer ring. Hardening in this case was obtained by cold working, such as hammering, rolling or some means for stretching the steel while at a temperature near 500" C. One means for stretching2 is to rotate the forged or rolled ring in a centrifugal machine so as to develop within it stress higher than

Jan 1, 1931

By C. B. Alcock, R. A. Oriani

Some simple models of solutions are described; these include the regular solution, the subregular solution, and the quasichemical model. The assunzption underlying these models, the physical signzficance thereof, and the experimental manifestations are discussed. Examples are presented from the fields of liquid and solid metallic solutions, liquid slags, mattes, liquid and solid ionic solutions, and mixed carbides to show under what conditions and for which systems these solution models are fair descriptions. The deviations of real solutions from the models are of theoretical interest. Some such deviations, both for dilute and for concentrated solutions, arc pointed out and their Physical sigtzzficance discussed. DURING the past half century there has been a gradual accumulation of thermodynamic data for systems of interest to the metallurgist. There remain many gaps in the data, however, and the metallurgist must often face the problem of estimation of thermodynamic quantities where measured values do not exist. One might hope that the experimental progress would be matched by theoretical advances which would make such estimations possible with a high degree of confidence. However, theoretical progress has been disappointingly slow even for the simplest kinds of solutions, and since the multicomponent systems in which the metallurgist is interested are very complex, one cannot expect theory to be of much help to the metallurgist. In this situation, therefore, it seems worthwhile to examine some simple models of solutions from two points of view: firstly, to see if such crude models represent the thermodynamic facts in as many types of solutions as possible sufficiently well for the needs of the metallurgist, and secondly to see what the deviations from such models show to be important for consideration by theorists. BOND ENERGY MODELS OF SOLUTIONS The simple models that we will examine from these points of view may be termed statistical models, in that they are concerned with the thermodynamic consequences of some simple assumptions about the energy of an assembly of atoms, molecules, or ions, and do not inquire into the physical basis of the interaction. The underlying assumption of these models is that the energy of an assembly of molecules (by which we include also atoms or ions) is given by the sum over all interaction energies of molecules taken two at a time; we will discuss only those models in which the pairwise interactions are restricted to those between nearest neighbors. Thus, in a pure substance of bond energy EAA, the internal energy (with respect to some specific reference state) will be expressed as NAA EAA where NAA is the number of nearest-neighbor pairs. A solution of molecules A and B will be characterized by NAA EAA + NBB EBB + NAB EAB where the Eij represent the bond energies of the nearest-neighbor i-j pairs. If one assumes that the EAA and EBB are the same in the pure components as in the solution, and that the coordination numbers in the two pure substances and in the solution are the same, then the energy of the solution with respect to the pure components (i.e., the energy of solution) is a function of the following linear combination of the bond energies: EAB - 1/2(EAA +EBB) = w. The thermodynamically ideal solution is defined as one in which the activity of each component is equal to the mole fraction of that component at all concentrations and all temperatures. It follows that

Jan 1, 1962

By C. R. Woodcock, J. S. Mason

In almost any situation where particulate or granular bulk solids have to be conveyed, whether for a distance of a few metres or for many hundreds of metres, a pneumatic conveying system may be considered. Conveying by pipeline is convenient and clean, but running costs may be substantial because of the heavy air consumption and the trend has therefore been towards dense-phase transport in which the ratio of conveyed solids to conveying air is kept high. This paper concentrates on air-float conveying, which can be regarded as an extreme form of dense-phase conveying where the bulk solid is fluidised in a channel and then caused to flow, either by inclining the channel or creating a pressure gradient along 'it. Various designs of air-float conveyor for upward, horizontal and down- ward transport of powders are discussed, with special emphasis on the latter case. In situations where a continuous downward slope can be provided, the combination of air-fluidisation and gravity flow results in a conveying system that, for many kinds of bulk particulate solid, would be hard to better in terms of convenience, reliability and economy. The paper is concluded with a discussion of design features and performance of practical air-gravity conveyors, involving the handling of various bulk particulate solids, both in research and in full-scale industria1 applications.

Jan 1, 1980

By A. W. Schlechten, W. J. Kroll

As this paper is written, the only method for the commercial production of lithium metal is by the fusion electrolysis of LiCl-KCl mixtures, as first proposed by Guntz.2 The details of the industrial process have not been made public but Osborg8 stated that an efficiency of more than go pct is obtained with a lithium metal recovery above 95 pct and that the metal is 99.5 pct pure. Pletenev9 gave a power consumption of 66 kw-hr per kilogram of lithium metal produced with a salt consumption of 9 kg of LiCl and 0.4 kg of KCI. Pletenev's figures indicate a somewhat lower recovery than that given by Osborg. In a recent report on German lithium plants, Motock7 gives figures that are also less favorable than those reported by Osborg. At the German plants the lithium recovery in electrolysis was only 83.4 pct, with a power consumption of too kw-hr per kilogram of lithium. The metal averaged only 97 pct pure, with sodium and potassium as the chief impurities. The presence of SO2, SO3, Si02, Ba, Ca, and appreciable amounts of Na and Fe2O3 were especially disturbing in the electrolysis, and it was necessary to run the cell for some time to eliminate most of these impurities and condition the bath. It may be noted here that most of these impurities do not interfere with a thermal reduction process. These facts show that the present method of producing lithium is fairly efficient and would suggest that other methods could not compete. However, fusion electrolysis has certain drawbacks, such as the necessity of supplying costly, low-voltage direct current and of collecting and processing the anodic chlorine if it is not to be wasted. An even greater disadvantage is that lithium chloride must be used for an electrolyte. It is one of the most expensive salts of lithium, since it cannot be produced in anhydrous form by precipitation from aqueous solution, as is done with LiF or Li2CO3. The reduction of lithium by a vacuum process similar to the ferrosilicon method for the production of magnesium would have certain advantages. Small units, such as Pidgeon retorts, would give flexibility of production to meet demand, and a small plant would require moderate capital outlay. There is a possibility of using idle Government-owned magnesium plants for such purposes. The raw materials needed for vacuum thermal reduction would not have to be extremely pure, especially with respect to the iron and calcium content. This paper describes a series of experiments to determine the effectiveness of various agents for the reduction of lithium compounds. The investigation is part of a program of vacuum metallurgy con-

Jan 1, 1947

By H. D. Hoskold

It was not for the purpose of asserting any superior knowledge or authority, but simply of clearing up, in greater detail, some points casually mentioned in Mr. Scott's able paper, that the writer entered, some two years ago, into the discussion which that paper initiated. In such matters there is always room for differences of judgment, as well as for additional data, which may modify or complete the conclusions even of the best authorities. Those who are immersed in the duties of practical administration or work in the field, and who, being remote from the great scientific national libraries, are obliged to rely on their private collections, and to supplement them by their recollections of earlier studies, labor under special disadvantages in such a discussion; and it must be to the scientific and engineering world a matter for gratitude that Mr. Lyman has been willing to give the benefit of his advantages in this respect. Mr. Lyman would, however, doubtless at once disclaim the conclusion that his masterly summary constitutes " the last word " on this subject, and welcome further evidence, comment and criticism, such as the various contributors may continue to offer. This, therefore, is the motive, and must be the excuse, of the introduction by the writer of the following observations. The Miners' Dial.—Many years since, the writer employed a miners' dial, older in type than Fig. 12,* but without any attached spirit-level, made by Thomas Jones, a pupil of the great Ramsden. Jones was one of the old London makers and opticians, and enjoyed great reputation for accuracy in the con-

Jan 1, 1902

By H. S. Price, J. C. Cavendish, R. S. Varga

This paper presents a new technique for solving some of the partial differential equations that are commonly used in simulating reservoir performance. The results of applying this technique to a simple problem show that one obtains accurate pressure values near wells, as well as accurate pressure pdients, which can be explicitly calculated. The method is completely rigorous in that convergence of the discrete numerical solution to the continuous solution for both pressure and pressure gradient is established. High-order, piecewise-polynomial approximations are used near the wells where pressure gradients are steep, while low-order, piecewise-polynomial approximations are used elsewhere to reduce greatly the calculation time. This combination is shown to give a uniformly good approximation to the solution. These approximations, obtained by using a Galerkin process with suitable Hermite subspaces, are shown to be theoretically and numerically superior to the usual approximations obtained from standard finite-difference techniques. Not only are much greater accuracies obtained, but computer times are also greatly reduced. The application of this technique to multiphase flow problems (e.g., single well coning problems) would have considerable practical interest, but such extensions of this technique with full mathematical rigor have not been made as yet. However, the numerical methods presented here are general, and in principle extend to multidimensional, multiphase flow. Moreover, the preliminary results given in this paper are sufficiently encouraging that we feel the effort in attempting these extensions is justified. INTRODUCTION The problem of obtaining accurate pressure distributions and pressure gradients around wells is of considerable importance in the numerical simulation of reservoir performance. The most common approach to solving this problem is to use finite difference techniques (see McCarty and Barfield9 or Peaceman and Rachfordl0). This approach, however, has many disadvantages, the major one being that many grid points are generally necessary for accurately describing the pressure distribution and the pressure gradient around wells. This need for a fine grid results in large computer times and often in prohibitively high costs. Besides investigating the method of finite differences, some authors, such as Welge and weber17 and Roper, Merchant and Duvall,13 have considered a combination of analytical and numerical techniques with some success. These approaches, however, are all nonrigorous and quite often cannot even be applied. In this paper, we present a numerical formulation of high-order accuracy, based on the Galerkin method, for solving this problem. We treat here only the partial differential equation that describes steady-state, single-phase flow. However, the methods presented are general and in principle extend to multidimensional, multiphase flow. Specifically we treat special cases of the problem in two dimensions described by: where G is a rectangle (with sides parallel to the coordinate axis) with boundary ?G, ?/?n denotes the outward normal, and y and B are non-negative constants such that y + B > 0.

Jan 1, 1970

By J. R. Low, M. Gensamer

During the course of an investigation into the drawability of automobile-body sheet steel, it became apparent that certain advantages would be possessed by a deep-drawing steel with a very low yield strength, but almost normal tensile strength, provided a reduction in yield strength could be accomplished without sacrifice of ductility and fine grain size. It would also be desirable to have this steel free from strainaging; that is, free from the tendency for the yield point to return after it had been eliminated by straining. It was known that wet hydrogen treatment acted to eliminate aging, but as carried out by other investigators, at relatively high temperatures, this treatment resulted in grain coarsening. It has been established by some of the experiments reported in this paper that all of these objectives can be accomplished by treatment in wet hydrogen at a low temperature, in the neighborhood of 720°C. The time of treatment is relatively short (about 3 hr. to completion with 20-gauge sheet) if the water content of the hydrogen atmosphere is made fairly high, say almost 30 per cent by volume. At this temperature, the grain size remains fine in the time required. After this treatment sheet reduced the usual amount by cold-rolling has a grain size of about A.S.T.M. No. 7. The yield point is completely eliminated, and the yield strength is reduced to a very low value, in the neighborhood of 15,000 lb. per sq. in. The stress-strain curve departs gradually from the straight-line elastic part after the fashion of nonferrous deep-drawing alloys. This elimination of the yield point is accompanied by a very low indentation hardness; for example, 32 Rockwell B or even lower. There is no aging as measured by increase in the yield strength upon aging at room temperature or for 3 hr. at 200°C., after stretching about 10 per cent in tension. Tensile strength is only slightly less than the box-annealed sheet, seldom dropping much below 40,000 lb. per sq. in. Elongation is practically unchanged, or increased slightly. The term yield point, as here used, refers to the phenomenon of heterogeneous deformation occurring at a substantially constant load, observed principally in annealed low-carbon steels. If such a steel is loaded in tension, the load increases steadily with elastic strain, suddenly falls, fluctuates slightly about some constant value for a time and then begins to rise again as deformation proceeds. The maximum initial load before the sudden drop is generally called the "upper yield point"; the value of the load where deformation proceeds at a

Jan 1, 1943

By V. R. Garfias, R. V. Whetzel, J. W. Ristori

Since the entry of the United States into global war, virtually all data and information necessary for compiling figures on world petroleum consumption have become unavailable. This situation undoubtedly will continue until the world petroleum industry can return to a peacetime basis. During the past 10 years, the authors, by publishing annual estimates of .world consumption, have attempted to emphasize the importance of a yearly world-wide survey of petroleum supply and demand. It is beconling more and more evident that statistics for the United States alone can no longer give a comprehensive idea of the state of the petroleum industry, even within the United States itself. Therefore, when conditions in the industry again become normal, it is the hope of the authors that those bureaus equipped to do so will carry forward the study of petroleum supply and demand on a world-wide basis. Enough data and information are available, however, to attempt a rough estimate of world output of crude petroleum and petroleum substitutes for 1942, which to some extent may reflect the trend of world consumption. This estimate by countries, as compared with the output in 1941, is shown in Table I. The world production of crude petroleum and petroleum substitutes for 1942 is estimated at 2,208,000,000 bbl., or a decrease of 171,000,000 bbl. under 1941. Crude production is believed to have decreased by about 200,000,000 bbl., (about 9 per cent); while petroleum substitutes increased by 28,500,000 bbl., (nearly 20 per cent). The decline of crude output in the United States is estimated at 19,000,000 bb1.—less than 2 per cent; while that in foreign countries is estimated at 180,000,000 bbl., or more than 20 per cent. The marked decline abroad is due largely to losses in Venezuela and Colombia, where the lack of ocean transportation became the controlling factor, and in the East Indies and Burma, where military invasion brought about the destruction of the fields. The production of petroleum substitutes in 1942 apparently reached a new high figure of 7.5 per cent of the total world petroleum output. The important features of petroleum production outside of the United States are the changes that have taken place during the year in the supply of the Axis countries. In Japan the output for 1941 was estimated at 8,800,000 bbl., 5,500,000 of which were petroleum substitutes. It is believed that the output of synthetic oils during 1942 substantially increased, raising the total interior production of Japan to nearly 10,-ooo,ooo bbl. Also, during 1942 Japanese armed forces gained possession of oil fields having a normal peacetime output of about 78,000,000 bbl. per year. The production of these areas for 1942 is estimated at some 23,000,000 bbl., which indicates that Japan is now getting at least 33,000,000 bbl. a year, which exceeds by 8,000,000 bbl. Its

Jan 1, 1943

By J. W. Ristori, V. R. Garfias, R. V. Whetzel

Since the entry of the United States into global war, virtually all data and information necessary for compiling figures on world petroleum consumption have become unavailable. This situation undoubtedly will continue until the world petroleum industry can return to a peacetime basis. During the past 10 years, the authors, by publishing annual estimates of .world consumption, have attempted to emphasize the importance of a yearly world-wide survey of petroleum supply and demand. It is beconling more and more evident that statistics for the United States alone can no longer give a comprehensive idea of the state of the petroleum industry, even within the United States itself. Therefore, when conditions in the industry again become normal, it is the hope of the authors that those bureaus equipped to do so will carry forward the study of petroleum supply and demand on a world-wide basis. Enough data and information are available, however, to attempt a rough estimate of world output of crude petroleum and petroleum substitutes for 1942, which to some extent may reflect the trend of world consumption. This estimate by countries, as compared with the output in 1941, is shown in Table I. The world production of crude petroleum and petroleum substitutes for 1942 is estimated at 2,208,000,000 bbl., or a decrease of 171,000,000 bbl. under 1941. Crude production is believed to have decreased by about 200,000,000 bbl., (about 9 per cent); while petroleum substitutes increased by 28,500,000 bbl., (nearly 20 per cent). The decline of crude output in the United States is estimated at 19,000,000 bb1.—less than 2 per cent; while that in foreign countries is estimated at 180,000,000 bbl., or more than 20 per cent. The marked decline abroad is due largely to losses in Venezuela and Colombia, where the lack of ocean transportation became the controlling factor, and in the East Indies and Burma, where military invasion brought about the destruction of the fields. The production of petroleum substitutes in 1942 apparently reached a new high figure of 7.5 per cent of the total world petroleum output. The important features of petroleum production outside of the United States are the changes that have taken place during the year in the supply of the Axis countries. In Japan the output for 1941 was estimated at 8,800,000 bbl., 5,500,000 of which were petroleum substitutes. It is believed that the output of synthetic oils during 1942 substantially increased, raising the total interior production of Japan to nearly 10,-ooo,ooo bbl. Also, during 1942 Japanese armed forces gained possession of oil fields having a normal peacetime output of about 78,000,000 bbl. per year. The production of these areas for 1942 is estimated at some 23,000,000 bbl., which indicates that Japan is now getting at least 33,000,000 bbl. a year, which exceeds by 8,000,000 bbl. Its

Jan 1, 1943

By NILS DANIELSEN

THE name of Swedish charcoal iron will probably bring to the memory of many old consumers an extremely tough and ductile iron which was formerly used in considerable quantities for common blacksmith purposes. To-day very little of this iron goes to such kind of work. Swedish charcoal iron is merely a speciality which is chosen whenever its remark¬able properties can be utilized. By giving a rough sketch of the manufacturing process of Swedish charcoal iron, the character of the iron, its weak as well as its strong points will more easily be understood. Swedish charcoal iron is a wrought iron also known in the United States under the name of Norway iron and Swedish Lancashire iron. The name Norway iron seems to have been attached to the product for the reason that in the earlier days it was generally brought into the States by Norwegian ships. However no iron of this kind is now made in Norway. The reason for the name Swedish Lancashire iron is that the manufac¬turing process emanated from Lancashier in England, the method being generally adopted in Sweden in the years 1831-1850. Today this iron is, with the exception of one plant in the United States, made in no place in the world outside of Sweden.

Jan 1, 1924

For the year ending February, 1923 PRESIDENT ARTHUR S. DWIGHT, District 0 NEW YORK, N. Y. PAST PRESIDENTS HERBERT HOOVER, District 4 WASHINGTON, D. C. EDWIN LUDLOW, District 0 NEW YORK, N. Y. FIRST VICE-PRESIDENT J. V. W. REYNDERS NEW YORK, N. Y. TREASURER CHARLES F. RAND NEW YORK, N. Y. SECRETARY FREDERICK F. SHARPLESS,. . . . . NEW YORK, N. Y. ASSISTANT SECRETARY PERCY E. BARBOUR NEW YORK, N. Y.

Jan 7, 1922

By Charles S. Barrett

THIS paper is a progress report covering metallographic applications of the electron microscope that have been made during the past year at Carnegie Institute of Technology. An account is presented of the techniques that have been most satisfactory, the difficulties encountered, the resolution obtained, and the peculiarities that have been noted in the microstructures. About 12m exposures have been made during the year on the instrument, which is an RCA type B2 transmission microscope,1 and a number of these have been selected to illustrate the results obtained. Prints are also included showing the common types of falsities-to borrow a term from the biological field, the "artifacts." In brief, the paper is a record of our attempt to determine the value of the electron microscope in the study of the structure of metals and alloys. n addition to comments on techniques and the quality of photomicrographs obtainable with them, the paper discusses the nature of the etch attack on a few metals, and the possible relation between the fine structure revealed by etching and the mosaic block structure of the grains. Since numerous papers and reviews are available on the subject of imperfection in crystals, the comments here may be very brief; in fact, are restricted almost entirely to points having to do with recent theories relating the strength of metals to imperfections and to spacings of slip lines. SPECIMEN PREPARATION AND PHOTOGRAPHS Mechanical polishing by hand was used throughout this work. Precautions that must be taken in microscopy at high magnification, which have been well explained by Vilella in his book on Metallographic Technique for Steel, are likewise important with the electron microscope. This applies particularly to the need for repeated polishing and etching (each successive polish becoming less severe and each etch lighter), since the final etch should in general be no heavier than is used for oil-immersion optical microscopy and in many instances should be much lighter (compare Figs. 6a and 7a, 6d and 7b). An extremely light etch, of course, is incapable of cutting through a flowed layer of appreciable thickness. Unquestionably it would be very advantageous in each instance to compare the structures obtained by electrolytic polishing with those obtained by mechanical polishing, but difficulties with the electrolytic method have prevented this in the following collection of prints. The choice of etchant is important, of course; for example, picral proved superior to nital for tempered martensite. With the exception of Figs. Ib and IC, the replicas used were of silica, deposited up0n polystyrene and floated from the polystyrene in ethyl bromide according to polystyrene in ethyl bromide according to the method of Heidenreich and Peck.2 The samples were mounted in Bakelite, polished and etched, then the polished Bakelite

Jan 1, 1943