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By F. L. Fayers, J. W. Sheldon

It has been a matter of concern to the petroleum industry to determine what effect the capillary term has on saturation profiles, since these profiles determine ultimate economic oil recovery. In their original solution of the non-capillary two-phase flow problem, Buckley and Leverett&apos; showed that solutions of the two-phase flow equations became multiple-valued in saturation. Since it is physically unrealistic for saturation to have more than one value at a given position, Buckley and Leverett resolved this difficulty by introducing a saturation discontinuity or "shock". They evaluated the strength and position of the shock from material balance considerations. Recently Sheldon, Zondek and Cardwell&apos; have demonstrated that the method of characteristics can be used to solve this and related problems. Owing to capillarity it is physically unlikely that saturation shocks occur in an oil reservoir. Buckley and Leverett suggested that the effects of interfacial tensions should be included in the fluid flow equations, if the solutions are to give continuous single-valued saturation distributions. An analogy to this problem is encountered in the theory of wpersonic compressible flow where the introduction of the viscous term eliminates shock behavior. However, the mathematical form of the capillary term in the porous medium fluid flow equations differs from the viscosity term in the Navier-Stokes equation. This paper demons~rates that capillarity does eliminate the triple-valued behavior and indicates the magnitude of capillary and gravity effects on the saturation profile for a variety of systems. DERIVATION OF LAGRANGIAN AND EULERIAN FORMS OF THE DISPLACEMENT EQUATION The equations representing capillary, two-phase flow are given by applying Darcy&apos;s law and a material balance condition for each phase. The familiar Darcy and material balance equations are as follows. ^U*^0......<3, ^^r=°......c« S is the saturation of the water phase, and B the inclination of the porous medium. Pressures in the oil and water phases differ by the capillary pressure associated with the interfacial tensions, P.-P.=pAS)..........(5) where p, is determined experimentally. The porous medium is said to be oil-wet if P, > Po and water-wet if P, < Po. If the fluids are incompressible and the total volumetric flow rate, q, is constant, then v, f v,, = q...........(6) By eliminating P.. /»,, and v, from Eqs. 1, 2, 5 and 6 it follows that It is convenient to normalize the variables in the problem after the manner of Handy and Hadley% so that Eqs. 3 and 7 become where j,, = —, the fractional flow of water; (F, is a capillary pressure normalizing constant.) Substitution of Eq. 9 into Eq. 8 gives In this partial differential equation for an initial value

By H. M. Dess, S. R. Bolin

A modifiedl Czochralski technique has been utilized to grow single crystals of YVO, pure or doped with europium or neodymium, from 1 to 2 in. long and 4 to 1/2 in. in dianz. An oxyhydrog-en gas-fired furftace zuas used in this ulork, and melts were contained in iridium crucibles. Successful application of the Czochralski ~vzethod was found to depend upon atmosphere control to prevent crusting and to limit melt decomposition, the establishment of symmetrical thermal gradients in the melt to obtain stable growth, and the selection of high-quality single-crystal seeds to prevent propagation of misorientations during growth and subsequent catastrophic cracking. The suitability of YVO4 as a host for laser-active trivalent rare earth ions has long been recognized. However, the problems associated with the growth of sufficiently large, good-quality single crystals have, until quite recently, seriously hindered satisfactory evaluation of the laser potentialities of this material. Both flux growth and Czochralski growth techniques were investigated at an early stage of interest in YVO,. The former method proved incapable of yielding crystals large enough for practical use,ly2 and the latter was beset with difficulties which took some considerable time to understand and overcome. Recently, however, the Czochralski growth process for YVO, has been improved along separate but similar lines of development by groups working independently in the Crystal Products Department of Union Carbide&apos;s Electronics Division and Bell Telephone Laboratories3 so that now good-quality single crystals of satisfactory size can be produced on a routine basis. Stimulated emission from a neodymium-doped YVO4 crystal grown by the Crystal Products Department of Union Carbide was obtained by O&apos;connor4 of MIT, Lincoln Labs. An oxyhydrogen gas-fired furnace was used in this work, Fig. 1, and melts were contained in iridium crucibles. The starting material was 99.9 to 99.99 pct pure YVO4 powder purchased from the Chemical and Metallurgical Division of the Sylvania Electric Products Co. Typical impurity levels, determined by spectrographic analyses, were as follows: Si, 50 to 500 ppm Al, Fe, Mg, 5 to 50 ppm Ni, Pb, Mo, Mn, Ce, Cs, 1 to 10 ppm Initially, YV04 powders predoped with neodymium or europium were obtained from Sylvania. Later, however, because of a desire to grow a series of crystals containing relatively broad concentration ranges of these dopants, it proved more convenient to start with pure YV04 and mechanically admix Nd2O3 or Eu@~ powders plus equimolar amounts of V2O5. The empty crucibles were preheated to 1900" to 1950oC, a temperature range where melting occurred readily. The powdered YVO4 feedstock was then added incrementally. However, a marked tendency toward

Jan 1, 1968

By Clarence Zener, Howard Clarke, Cyril Stanley Smith

The importance of cold-working in the fabrication of metals is in marked contrast with our ignorance as to the nature of the accompanying internal changes. The failure of the usual methods of testing to provide a consistent picture of these internal changes has given the incentive for the present program of investigating the effect of cold-working upon the internal friction of metals measured at small strain amplitudes. It has previously been shown1,2,3, that the internal friction introduced by cold-work is removed by annealing at comparatively low temperatures. In the present paper the following additional factors are investigated: (I) frequency of measurement, (2) amount of cold-work, (3) temperature of measurement. Special care was taken to minimize the internal friction due to causes other than cold-work. The present paper is purely experimental, the authors believing that any conclusions drawn from this work as to the nature of the internal changes accompanying cold-work would be premature.&apos;l PrEpaRations oF Specimens In this study of cold-work it was desirable to eliminate as far as possible all other sources of internal friction. One disturbing source is the lack of temperature equilibrium between adjacent crystallites of a vibrating specimen.4 Temperature equilibrium is aided by small grain size and by the use of low-frequency vibrations. Unless unduly long specimens are used, low frequencies can be obtained only in transverse vibrations. But in transverse vibrations a second source of internal friction is present, that arising from transverse thermal currents.5 The effect of these may be reduced by increasing the transverse dimensions. The grain size and transverse dimensions of the specimens were thus so chosen as to render the vibrations simultaneously nearly isothermal with respect to intercrystalline thermal currents, and nearly adiabatic with respect to transverse thermal currents. The material for this investigation was a 70-30 brass, part of the same lot of material that was used for some earlier studies on the effect of strain on proportional limit.10 It had the following composition: copper, 70.59 per cent; zinc, 29.39; lead, 0.01; iron, 0.01. This material was received from the brass mill in the form of 3/4-in. rod, cold-drawn to final size by a 65 per cent reduction of area from material that had been annealed to give a grain size of 0.060 mm, Rods of appropriate length were annealed for 2 hr. at 400°C. and cooled in air. The annealed rods (grain size, 0.012 mm.) were then stretched in a tension-testing machine, using special grips1&apos; to ensure axial application of the load. The rate

Jan 1, 1942

By Howard Clarke, Cyril Stanley Smith, Clarence Zener

The importance of cold-working in the fabrication of metals is in marked contrast with our ignorance as to the nature of the accompanying internal changes. The failure of the usual methods of testing to provide a consistent picture of these internal changes has given the incentive for the present program of investigating the effect of cold-working upon the internal friction of metals measured at small strain amplitudes. It has previously been shown1,2,3, that the internal friction introduced by cold-work is removed by annealing at comparatively low temperatures. In the present paper the following additional factors are investigated: (I) frequency of measurement, (2) amount of cold-work, (3) temperature of measurement. Special care was taken to minimize the internal friction due to causes other than cold-work. The present paper is purely experimental, the authors believing that any conclusions drawn from this work as to the nature of the internal changes accompanying cold-work would be premature.&apos;l PrEpaRations oF Specimens In this study of cold-work it was desirable to eliminate as far as possible all other sources of internal friction. One disturbing source is the lack of temperature equilibrium between adjacent crystallites of a vibrating specimen.4 Temperature equilibrium is aided by small grain size and by the use of low-frequency vibrations. Unless unduly long specimens are used, low frequencies can be obtained only in transverse vibrations. But in transverse vibrations a second source of internal friction is present, that arising from transverse thermal currents.5 The effect of these may be reduced by increasing the transverse dimensions. The grain size and transverse dimensions of the specimens were thus so chosen as to render the vibrations simultaneously nearly isothermal with respect to intercrystalline thermal currents, and nearly adiabatic with respect to transverse thermal currents. The material for this investigation was a 70-30 brass, part of the same lot of material that was used for some earlier studies on the effect of strain on proportional limit.10 It had the following composition: copper, 70.59 per cent; zinc, 29.39; lead, 0.01; iron, 0.01. This material was received from the brass mill in the form of 3/4-in. rod, cold-drawn to final size by a 65 per cent reduction of area from material that had been annealed to give a grain size of 0.060 mm, Rods of appropriate length were annealed for 2 hr. at 400°C. and cooled in air. The annealed rods (grain size, 0.012 mm.) were then stretched in a tension-testing machine, using special grips1&apos; to ensure axial application of the load. The rate

Jan 1, 1942

By Howard Clarke, Cyril Stanley Smith, Clarence Zener

THE importance of cold-working in the fabrication of metals is in marked contrast with our ignorance as to the nature of the accompanying internal changes. The failure of the usual methods of testing to provide a consistent picture of these internal changes has given the incentive for the present program of investigating the effect of cold-working upon the internal friction of metals measured at small strain amplitudes. It has previously been shown1,2,3, that the internal friction introduced by cold-work is removed by annealing at comparatively low temperatures. In the present paper the following additional factors are investigated: (I) frequency of measurement, (2) amount of cold-work, (3) temperature of measurement. Special care was taken to minimize the internal friction due to causes other than cold-work. The present paper is purely experimental, the authors believing that any conclusions drawn from this work as to the nature of the internal changes accompanying cold-work would be premature." PREPARATIONS OF SPECIMENS In this study of cold-work it was desirable to eliminate as far as possible all other sources of internal friction. One disturbing source is the lack of temperature equilibrium between adjacent crystallites of a vibrating specimen.4 Temperature equilibrium is aided by small grain size and by the use of low-frequency vibrations. Unless unduly long specimens are used, low frequencies can be obtained only in transverse vibrations. But in transverse vibrations a second source of internal frictions is present, that arising from transverse thermal currents.5 The effect of these may be reduced by increasing the transverse dimensions. The grain size and transverse dimensions of the specimens were thus so chosen as to render the vibrations simultaneously nearly isothermal with respect to intercrystalline thermal currents, and nearly adiabatic with respect to transverse thermal currents. The material for this investigation was a 70-30 brass, part of the same lot of material that was used for some earlier studies on the effect of strain on proportional limit.10 It had the following composition: copper, 70.59 per cent; zinc, 29.39; lead, 0.01; iron, 0.01. This material was received from the brass mill in the form of 3/4-in. rod, cold-drawn to final size by a 65 per cent reduction of area from material that had been annealed to give a grain size of 0.060 mm. Rods of appropriate length were annealed for 2 hr. at 400°C. and cooled in air. The annealed rods (grain size, 0.012 mm.) were then stretched in a tensiontesting machine, using special grips10 to ensure axial application of the load. The rate

Jan 1, 1941

By R. I. Jaffee, J. G. Dunleavy, H. R. Ogden, Webster Hodge

INTRODUCTION EARLY in 1946, at the instigation of the U. S. Army Signal Corps, the authors made an extensive survey of the available literature covering high-strength, high-conductivity alloys. For the purposes of the Signal Corps, the minimum tensile strength to be considered was 150,000 psi, together with at least 50 pct IACS conductivity. No single alloy was found to be in production, or mentioned in the literature, which had this combination of properties. The constitution diagram for the iron-copper alloys is not well established in the respect to the two-liquid region. Fig I, taken from the 1939 Ed. of the ASM Metals Handbook, shows a two-liquid system existing above the liquidus temperature, but disconnected from it. Although Ruer and Fick1 and Ruer and Goerens2 definitely established the fact that two liquid layers could occur in the system, Ruer3 was not convinced that the line off immiscibility was closed in the center. Maddocks and Claussen4 found no liquid immiscibility at temperatures up to 1570°C in alloys containing almost no carbon. Although the diagram would indicate age hardening of the copper-iron alloys is possible, Hanson and Fords found that little hardening effect could be obtained. However, Gordon and Cohen6 reported that the response is better if the quenching is very efficient. Although iron has a potent effect on the conductivity of copper, Hanson and Ford5 have shown that, when hot-rolled copper iron alloys are aged at 1200°F, the electrical conductivity decreases sharply with iron contents up to 0.2 pct Fe, and then levels off at conductivities between 60 to 70 pct IACS with compositions to 2.1 pct Fe. They also found that aging did not increase the tensile strength, although increasing iron content gave a moderate improvement in strength. High-strength copper-iron alloys, usually containing about 60 pct iron, had been reported by Smith and Palmer.7 They found that an alloy containing 56.4 pct copper, 0.21 pct magnesium, balance iron, would give a maximum tensile strength of 170,000 psi and an electrical conductivity of slightly over 35 pct IACS. The alloy could also be processed to have 150,000 psi tensile strength, and about 41 pct IACS conductivity. Decreasing the iron content increased the electrical conductivity, but the long mushy range during freezing of the alloy containing 10 to 20 pct iron made the production of good castings difficult, In spite of the difficulty encountered by Smith and Palmer with alloys of around 20 pct iron, it was decided to make a rather complete investigation 0f this type of alloy. As a result 0f this investigation, a method of alloying and fabricating copper alloys containing 10 to 15 pct iron was developed

Jan 1, 1948

By J. D. Rice, H. H. Rachford, G. H. Bruce, D. W. Peaceman

The problem of unsteady-state gas flow through porous media leads to a second-order non-linear partial differential equation for which no analytical solution has been found. In this paper a stable numerical procedure is developed for solving the equation for production of gas at constant rate from linear and radial systems. An electronic digital computer is used to perform the numerical integration using an implicit form of an approximating difference equation. Solutions are presented in graphical form for various values of dimension-less parameters. The solutions are compared with the laboratory study of gas depletion in a linear system. INTRODUCTION Production of fluids from porous rock reservoirs is essentially a transient process. Transient gradients develop as soon as production begins, and further withdrawals continue to cause disturbances which propagate throughout the reservoir, each adding in some way to the prior ones. A correct mathematical analysis of this behavior is complicated by the fact that the transient or unsteady-state flow of compressible fluids must be described by difficult second-order partial differential equations. As a practical matter, three distinctly different cases arise: 1. Flow of single-phase liquid 2. Flow of gases 3. Multiphase flow The first of these has been found to give a linear second-order equation similar to the well-known heat flow equation. where 7 is fluid density, 8 is time, and a a constant for the system, provided d 7 = r cdp, where the compressibility, c, is constant over the range of pressure, p, considered. Solutions of Equation (1) for both linear and radial flow are available in several forms.2&apos;3&apos; On the other hand. the second case, which is the flow of gas, gives a non-linear second-order equation, the solution of which is not known. Although a number of approximate solutions have been proposed, each is limited in value by the associated simplifying assumptions. Inasmuch as the analysis of transient flow is limited to liquid systems, a solution of the second case is necessary if further progress is to be made in studying underground fluid movement. For this reason a solution of Equation (2) was undertaken by means of numerical integration of approximating difference equations. BASIC DIFFERENTIAL EQUATION Equation (2; is derived by combining the equation of continuity, the perfect gas law, and Darcy&apos;s law to give the basic differential equation Strictly speaking, the fluids present in a gas reservoir are not perfect gases. Furthermore, there are indications that over certain velocity ranges, Darcy&apos;s law is not applicable. It would not be practicable. however, to attempt to obtain numerical solutions which would take into account all the possible variations from these laws which could occur in actual systems. The

Jan 1, 1953

By G. M. Wiles

The increasing number of problems of the modem mine manager has led the author to discuss the art of management. He lists the principles concerning selection of personnel, exploitation and development, new equipment, process improvements, new processes, maintenance, operating cost data and public relations. Application of the principles to problems of mine startup, operation and rehabilitation are described. Since D. C. Jackling was famous for his adeptness at organizing and training teams of operating personnel, the subject of mine management is particularly appropriate for a Jackling Lecture. In fact, it is doubly appropriate because in very basic ways Jackling&apos;s career changed the nature of the tasks and challenges facing a mine manager. Management of mines, of course, is the art of finding and winning minerals economically from the earth&apos;s crust, and it involves the use of all the engineering sciences. But also of prime importance is a skill which is not yet a science - the area of management often referred to as human engineering. Since expenditures on staff and labor may well involve more than 50% of the direct costs of operating a mine, ability at human engineering is just as important as the ability to plan and put into effect the most efficient operating procedures. In addition to his ability to select and train operating personnel, Jackling possessed, to a degree unmatched by many of his contemporaries, broad, analytical powers covering both the economics and operating phases of large scale mineral extraction. His breadth of vision found its greatest expression at the time he analyzed the Utah copper deposit. Fortunately, Messrs. Penrose and Gemmell had enough faith in his analyses to furnish the capital needed to begin operations. The result, as is well known to all of you, was Kennecott&apos;s lucrative Utah copper mine — and the beginning of the open pit porphyry copper era. The Utah copper mine, and Jackling&apos;s subsequent similar successes in Arizona, New Mexico and Nevada, had one thing in common —all of these large porphyry deposits were worthless until open pit, large daily tonnage schemes were developed for their exploitation. The successful development of such schemes made vast new mineral resources available for economic exploitation. But at the same time, the trend away from smaller high grade operations in favor of the far more complicated operations required to handle large deposits of low grade ore have greatly altered a mine manager&apos;s problems. We are all familiar with the saying "mines make managers." There is still some truth in this statement, but far less than there used to be in the days when high grade properties were the rule rather than the exception. When high grade orebodies prevailed, many managers, superficially at least, could not make a mistake because the profits of their mines

Jan 1, 1962

By C. R. Holmgren

A large consolidated sand core was used in this investigation. Four groups of experiments including gas drives, water drives, and water drives combined with gas injection, were made. The results of the gas-drive experiments indicate that greater ultimate recovery may be obtained by higher pressure gradients. However, other considerations challenge the absolute veracity of this conclusion. Results indicate that with connate water present and a low pressure gradient during a gas drive, less gas is required to produce a given amount of oil. The saturation gradient determined during a gas drive is presented. Results of the water-drive experiments indicate that the recovery of oil is not a function of either gradient Or input rate. The presence of initial gas saturation resulted in a slightly lower final oil saturation. Injection of sufficient gas to maintain the initial gas saturation during a water drive resulted in lower final oil saturation. Introduction With the demand for petroleum products reaching an all-time record high and the location and exploitation of new reserves becoming more difficult and expensive, the oil industry must look to more thorough and efficient methods of producing the petroleum already located. Much of the previous work along these lines is exploratory and suggests a more complete investigation. For example, a great amount of laboratory work has been done on flooding sands initially saturated roo pct with oil. Since sands saturated roo pct with oil rarely, if ever, exist in nature, and because the water content is a vital factor in the ultimate recovery from the sand, laboratory investigations on cores without water must be supplemented by comparable work on cores with water present.1&apos;2 Other investigators have done a considerable amount of laboratory work using gas and water drives.3 Krutter and Day4 have reported results of investigations using cores saturated IOO pct with oil and have concluded that " the ultimate recovery obtained, using air drive, from a completely oil-saturated core depends on the pressure gradients used. The higher the pressure gradient, the greater will be the recovery until a certain Pressure range is reached above which the reward of increased recovery is much smaller for similar increments in pressure." Yuster and Day6 conclude that less gas and less time are required to produce a given quantity of oil at high pressure gradients than at low pressure gradients; they also conclude that an increase in the viscosity of the oil requires a proportionate increase in the gas needed for recovery. Their results indicate that the gas required to produce a given quantity of oil is greatly reduced by the presence of connate water. R. C. Earlougher2 concluded, based on results of water-flooding a large number of

Jan 1, 1949

By H. L. Washburn, G. L. Judy

DURING recent years thermal drying of fine coal has increased at a tremendous rate, but very little discussion of the several excellent units has found its way into print. This is particularly true for operating and maintenance costs, and the operator who is faced with his first fine coal drying installation must depend chiefly on hearsay when trying to determine what his drying costs will be. This article presents the maintenance and operating costs for the seven drying units now installed in preparation plants of Pittsburgh Consolidation Coal Co. and lists other cost information that should be obtained before any particular drying unit is selected. Plant Description: The fine coal drying section of Plant A consists of four Flash driers operating on two furnaces equipped with spreader stokers. Plant B has one Flash drier operating (together with a screen-type coarse coal drier) on one furnace equipped with a spreader stoker. Plant C has two Cascade-type driers operating on a single furnace with a spreader stoker. Plant Costs: Tables I, 11, and III present the cost of operating these units as reported by the individ- ual plants. As can be seen, the labor rates vary, depending on the amount of overtime paid and the time interval the cost figures cover. There is considerable variation in thermal units used and in the value given to the thermal units at the particular mine. There is some difference in power costs at a given location and, finally, the power costs of conveyors leading to the drying plants were included in some cases. Maintenance supply costs are simply a tabulation of the cost of all supplies used on the driers, furnaces, and stokers. Depreciation is not included, and the tables omit items such as supervision, plant cleanup, oiling, general maintenance, taxes, and insurance. These tables in themselves do not offer a true comparison of costs. This information must be reduced to some common basis. But what is this common basis to be? A mine operator must calculate his overall mine and preparation plant costs in terms of tons of clean coal sold. Unit costs on pieces of equipment within a given plant are correctly calculated on the same basis. However, when unit costs are compared between one plant and another, some thought must be given to unit design. This reasoning is similar to the old argument concerning i solid bowl vs basket-type centrifuges—the units themselves are not directly comparable without their supporting equipment. So it is with thermal driers. Except in rare cases of low entering moisture i content, driers are sized on the basis of water that must be evaporated, while the wear each unit gets de-

Jan 1, 1958

By R. T. Webber, B. B. Owen

THE vapor phase deposition of molybdenum and tungsten from the hexacarbonyls has been thoroughly investigated by Lander and Germer1 and shown to yield well-bonded coatings on a variety of hot metallic surfaces. They also demonstrated that chromium coatings2.3 could be similarly deposited, but did not investigate this metal extensively. Recently,4 conditions have been described by which this compound can be prepared in quantities sufficient for laboratory scale plating experiments, and it is the purpose of the present communication to outline the results of preliminary experiments upon the plating of chromium from its carbonyl. APPARATUS AND TECHNIQUE The apparatus used in these experiments is shown in Fig I. At one end, connected by a short length of rubber tubing, is a Cenco Hypervac 20 pumping continuously. At the opposite end is a needle valve which allows a small stream of purified hydrogen to flow through the apparatus. Connected in series are a trap T1, maintained at the temperature of dry ice and acetone, the plating chamber, and two traps T2 and T3 containing crystals of the carbonyl. T2 is kept in a constant temperature bath (not shown), while T3 is at room temperature. Stopcock S6 allows the hydrogen flow to by-pass the carbonyl traps. A McLeod gauge is connected so that it can measure the pressure at the pump through Ss, or the pressure at the plating chamber through S9 and S6. The standard (12 liter) volume connected by S5 is used to determine the volume included by S4, S6, Se, S10, the needle valve and the McLeod gauge. Knowledge of this volume allows calibration of the flow of hydrogen. The apparatus* is built entirely of pyrex, except for the needle valve, the rubber connection to the Hypervac, and the cover of the plating chamber. The plating chamber is water-jacketed, with a large brass top allowing insertion of the specimen to be plated. Set into the brass top is a ground glass stopper through which thermocouple leads are sealed. The thermocouple wires (pure Pt, and 87 pct Pt-13 pct Rh) serve the double purpose of measuring the specimen temperature and suspending it in the chamber. Surrounding the chamber is the coil of an induction heater, H. The apparatus is designed to allow variation of the following conditions: I, the specimen temperature, from room temperature to about 1000°C, 2, the carbonyl vapor pressure, from 40 to 220 microns, and 3, the hydrogen flow. In several runs, 0.8 to 1.8 pct of hydrogen sulfide was introduced through a needle valve that replaced S4. The vapor pressure of the carbonyl is

Jan 1, 1948

By Robert L. Gower, John H. Cash

Interconnections for integrated circuits operating at rnicrowaue frequencies rzust be formed as microwave transmission lines. This paper describes the fabrication of one type of microwave transmission line known as microstrip, which can be fabricated on momlithic integvated circuits by deposition of 0.1- to 2.0-mil-thick metal and dielectric films. A microstrip line consists of a narrow conducting strip separated from a gvound plane by a dielectric material. Thick films of good conducting materials are required for low loss at high frequencies. Vacuum-evaporation methods for depositing aluminum and silver films are described. The narrow conducting strip forming the top conductor is defined by photoresist-etching techniques after the thick rnetal film is deposited. Gold plating with a photoresist-masking technique is also used to forrrz thick metal conductors. The microstrip dielectric layer is formed by deposition of suitable dielectric films 0.1 to 2.0 mils thick. Several deposition techniques were investigated. Electron-beam evaporation of quartz is described. Electrical characteristics of deposited microstrip lines at microwave frequencies are included and the microwave power attenuation as a function of conductor and dielectric thickness is given. It is concluded that the deposition of microstrip transmission lines is a practical way to achieve low-loss interconnections in monolithic integrated circuits. CONNECTIONS between devices in low-frequency and digital circuits are usually made by connecting the devices with a length of conductor such as a metal lead oi- a wire. If this method were applied to microwave integrated circuits, the reactance of the connection due to the series inductance and parasitic capacitance would be very high, in fact too high to permit successful circuit operation. In addition, resonance and antenna effects would occur at high frequencies, especially when the connections approach the wavelength.&apos; Connections which are sections of transmis- sion line will overcome these difficulties. The electromagnetic field is confined to the volume of the transmission line, parasitic effects are not present, and circuit design utilizes familiar transmission-line techniques. TRANSMISSION LINES One type of transmission line geometrically adaptable to integrated circuits is known as micrstri. A microstrip line can be generated from a coaxial line as shown in Fig. l(a). The outer conductor of the coaxial line is distorted into an ellipse (b) and finally separated at the extremities of the ellipse to form the strip transmission line shown in (c). One of the ground planes is then removed, leaving a conducting ground plane and a narrow conducting strip separated by a dielectric. Two configurations of the microstrip line were considered in this investigation, Fig. 2. Type (a) is fabricated from a semiconductor slice with the ground plane and top conductor deposited on each side of the slice. The semiconductor slice serves as the die lec-

Jan 1, 1967

By R. T. Webber, R. B. Owen

The vapor phase deposition of molybdenum and tungsten from the hexacar-bonyls has been thoroughly investigated by Lander and Germerl, and shown to yield well-bonded coatings on a variety of hot metallic surfaces. They also demonstrated that chromium coatings2&apos;3 could be similarly deposited, but did not investigate this metal extensively. Recently, conditions have been described by which this compound can be prepared in quantities sufficient for laboratory scale plating experiments, and it is the purpose of the present communication to outline the results of preliminary experiments upon the plating of chromium from its carbonyl. Apparatus and Technique The apparatus used in these experiments is shown in Fig I. At one end, connected by a short length of rubber tubing, is a Cenco Hypervac 20 pumping continuously. At the opposite end is a needle valve which allows a small stream of purified hydrogen to flow through the apparatus. Connected in series are a trap T1, maintained at the temperature of dry ice and acetone, the plating chamber, and two traps T² and T3 containing crystals of the carbonyl. T² is kept in a constant temperature bath (not shown), while T³ is at room temperature. Stopcock S6 allows the hydrogen flow to by-pass the carbonyl traps. A McLeod gauge is connected so that it can measure the pressure at the pump through Se, or the pressure at the plating chamber through S9 and S6. The standard (12 liter) volume connected by Sb is used to determine the volume included by S4, S6, SB, Slot the needle valve and the McLeod gauge. Knowledge of this volume allows calibration of the flow of hydrogen. The apparatus* is built entirely of pyrex, except for the needle valve, the rubber connection to the Hypervac, and the cover of the plating chamber. The plating chamber is water-jacketed, with a large brass top allowing insertion of the specimen to be plated. Set into the brass top is a ground glass stopper through which thermocouple leads are sealed. The thermocouple wires (pure Pt, and 87 pct Pt-13 pct Rh) serve the double purpose of measuring the specimen temperature and suspending it in the chamber. Surrounding the chamber is the coil of an induction heater, H. The apparatus is designed to allow variation of the following conditions: (I) the specimen temperature, from room temperature to about 1000°C, (2) the carbonyl vapor pressure, from 40 to 220 microns, and (3) the hydrogen flow. In several runs, 0.8 to 1.8 PCt of hydrogen sulfide was introuced through a needle valve that replaced S4. The vapor pressure of the carbonyl is

Jan 1, 1949

By Ray Hammond Misener

THE purpose of this paper is to describe the installation of the pumping station on the 3314-ft. level of the Carlos Francisco mine of the Sociedad Minera Backus y Johnston del Peru, at Casapalca, Peru. However, so much preliminary work was necessary before the actual installation could be started that some of that work will be described briefly, in order to clarify the discussion of the main subject. The Sociedad Minera Backus y Johnston del Peru, a subsidiary of the Cerro de Pasco Copper Corporation, owns and operates a group of mines in the Casapalca district, of which the most important are the Carlos Francisco and the Aguas Calientes. These two mines, one mile apart, are connected on their 2100 and 2700-ft. levels. These are motor-haulage levels, equipped with 3 ½ -ton Baldwin-Westinghouse locomotives operating from a 260-volt d.c. overhead trolley. A 38-cu. ft. hopper-bottom car is used. Each mine has a 2 ½ -compartment, inclined (70°) winze shaft. The Aguas Calientes shaft, operating between its 2100 and 2900-ft. levels, is used only for men and materials; whereas the Carlos Francisco shaft, between the 1700 and 2700-ft. levels of that mine, is the main operating shaft for the district. All the ore from the Carlos Francisco and the Aguas Calientes mines is hoisted through the Carlos Francisco shaft. The ore produced in these mines is by-passed to the 2700-ft. level, where it is gathered by the electric trains, taken to the Carlos Francisco shaft and dumped into an ore pocket in front of the shaft. The ore is hoisted to the 1700-ft. level in 2-ton self-dumping skips and emptied into a 150-ton loading pocket. There it is loaded into electric trains and despatched to the concentrator through the Backus and Johnston tunnel, which is the main entry from Casapalca to all the mines in the Backus and Johnston group. DEVELOPMENT PROGRAM In 1934 the following development program was outlined for the Carlos Francisco and the Aguas Calientes mines: (1) to deepen the Carlos Francisco shaft from the 2700 to the 3400-ft. level, (2) to deepen the Aguas Calientes shaft from the 2900 to the 3300-ft. level, and (3) to connect the two shafts on the 3300-ft. level with a motor-haulage crosscut. Each mine was to be developed also on intermediate levels (2900 and 3100). The three levels were to be spaced 54 meters (177 ft.) floor to floor, measuring from the 2700-ft. level along the incline of the shaft. The Carlos Francisco mine, together with the section between it and the Aguas Calientes mine, produces 10,000 gal. of water per minute. A fault to the north

Jan 1, 1943

Manganese Resources in Relation to Domestic Consumption Discussion of paper by JOHN V. W. REYNDERS, presented at the Cleveland Meeting and issued, as Pamphlet No. 1656-C, with MINING AND METALLURGY, May, 1927. A. G. BETTS, Kinderhook, N. Y. (written discussion).-When a business concern hires an office boy, it takes on the first bright-appearing young chap to apply and pays him the prevailing rate of wages. One of the chief tasks the .office boy is supposed to be competent to perform, is to clean out the office. The manager of the business is highly competent in many lines, but for some reason lacks the ability to keep the office clean. To the steel man, it would seem that manganese is the office boy, and it is purchased just as found and offered to the purchasing agent. The steel mill is competent to perform many functions on a grand scale and with wonderful efficiency, but it is unable to make real steel. It is the function of the office boy, manganese, to do this. It is open to serious doubt if steel mill operators have ever taken seriously the metallurgy of the preparation of crude manganese. It has merely been found that some usable crude manganese may be obtained by running certain manganese ores through an iron furnace when not busy on anything else, or remote from iron ore, or with a lining that is about gone. It is, however, an entirely unwarranted assumption that the metallurgy of manganese has been worked out, or that the supplies of usable raw ore must be limited to materials of some specified analysis. There was a time when ores of copper, lead and zinc, for example, had to be rich and of specified analysis, to be usable, but the commercial raw materials of today bear little resemblance to such ores of the past. The discussions of manganese that I have seen are based on the assumption that the metallurgy of manganese is fully established and that the only usable manganese raw materials are of the kind used today. These discussions contain another error, not so much of statement, but of implication-that the tonnages of manganese materials in the United States are so much in this state and so much in that. When it requires a period of years and the expenditure of millions of dollars for a competent mining company to explore thoroughly a few acres of mining ground, is it not absurd to say that there are so many hundred tons of manganese ore in a certain state? This fact is not apt to be known fully in 10,000, years. I do not charge the mining engineers. who are on record, of making misstatements, because they merely say that so much

Jan 5, 1927

By Reuben B. Ellestad, Fremont F. Clarke

Lithium chemical plant extraction methods are discussed with reference to 1) base exchange with alkali sulphates; 2) processing based on roasting with lime; 3) miscellaneous methods; and 4) application of the Lithium Corp. process to extraction of lithium from run-of-mine, low grade spodumene ore, or concentrates. IN the early days of the lithium industry most of the production was from lepidolite, zinnwaldite, and amblygonite. Nearly all the early extraction processes described in the literature involve heating the finely ground mineral with sulphuric or hydrochloric acid. On subsequent water leaching most of the bases present in the mineral (especially aluminum) are dissolved as sulphates. As a result, the leach solution required extensive chemical purification before the lithium could be precipitated as carbonate. Following the remarkable growth of the lithium industry to its present size, zinnwaldite and amblygonite ores must be considered of minor importance only. Attention is now focused on spodumene, abundant enough in North America to be a major source of supply, and there are important supplies of lepidolite and petalite in Africa. The extraction processes described below all apply to spodumene, although several will also operate on other lithium minerals, such as petalite. Base Exchange with Alkali Sulphates: A distinct advance was made with the disclosures of Wadman and von Girsewalt. In these methods the finely ground silicate ore (spodumene or lepidolite) is intimately mixed with an excess of alkali sulphate (usually K2SO4) in at least a 1 to 1 proportion, and the mixture was heated to a relatively high temperature. Base exchange results, with the formation of lithium sulphate. A water leach dissolves the lithium sulphate, together with the excess potassium sulphate. Successful operation of this type of process requires very thorough grinding and mixing, as well as careful temperature control. The use of K2SO4 is objectionable from cost considerations since purification of lithium carbonate requires the use of potassium carbonate, if the K2SO4 is to be recovered and recycled. The lower solubility of K2SO4 as compared with Na2S04 is also objectionable, since it limits the concentration of the Li2SO4 solution to be precipitated by K2SO4. Early laboratory-scale investigation of this process by Lithium Corp. was not encouraging. Other related base exchange processes are those of Lindblad, Wallden, and Sivander3 and Sivander, Gard, Villestad, and Wallen4. The former covers the reaction of lithium silicate minerals with a sodium sulphate solution, at 100" to 300°C (under pressure), while the latter involves the extraction of silicate minerals with molten sodium sulphate. Both these processes would seem to be difficult and expensive to operate.

Jan 1, 1956

By A. H. Daane, W. J. Wunderlin, B. J. Beaudry

The solid solubility of holmium in copper, silver, and gold, determined using metallographic techniques, was found to be a maximum of 0.06, 2.4, and 3.2 wt pct, respectively, nt the eutectic temperatures. The temperatures of these eutectic horizontals, determined by differential thermal analysis, were found to be 868", 787", and 778"C, respectively. The first compound on the silver-rich side of the Ag-Ho system was found to be A&Ho2. In a study by Gold et al.,&apos; on the effect of small amounts of soluble impurities on the electrical resistance and thermoelectrical properties of copper, traces of iron were shown to have drastic effects on the thermoelectric power due to the magnetic scattering of the conduction electrons. Since little is known about the state of the iron ion when dissolved in copper, Gold had hoped to repeat these experiments using certain rare earths as the magnetic scattering centers; because of the tightly bound 4f electrons it is not expected that their spectroscopic state would be affected by alloying. In such an experiment the sole role of the trace rare-earth impurity would be to magnetically scatter the copper conduction electrons without producing appreciable distortions in the otherwise pure copper matrix. Since holmium was chosen for such a study because of its high magnetic moment, it was necessary to establish precisely its solid solubility in copper. The study was extended to include the solvents silver and gold, so that an evaluation of the data using classical solubility parameters could be made. No previously reported work on the systems of holmium with copper, silver, or gold was found in the literature. Information on the solubility of other rare earths in these three metals is also very meager. The solubility limit of yttrium in copper was reported as less than 1 wt pct2 and the solubility of praseodymium in gold as 0.35 wt pct,3 while no references were found on solubility studies of rare earths in silver. EXPERIMENTAL Materials. The materials used in this investigation were distilled holmium prepared in this Laboratory, OFHC* copper, electrorefined silver (99.9 *OFHC = oxygen-free high conductivity. pct), and gold with the analyses given in Table I. Sample Preparation. Samples weighing 1 to 2 g were prepared by arc-melting the components together on a water-cooled copper plate under purified argon atmosphere. The samples, turned and remelted at least five times to ensure homogeneity, showed weight changes of less than 0.1 wt pct after melting. Samples containing less than 0.7 wt pct Ho were prepared by diluting 1 to 2 wt pct Ho alloys with the pure solvent, while samples with concentrations greater than 0.7 wt pct Ho were prepared directly from the metals. The samples were wrapped in tantalum foil, sealed in outgassed Vycor tubing under helium, annealed at the desired temperature for at least 24 hr, and then quenched by shattering the Vycor tube in cold water. Metallographic Methods. Standard mechanical polishing methods were used in preparing the silver and gold alloys for examination, while the copper alloys were electropolished using a 40 pct solution

Jan 1, 1963

By N. A. Gokcen

EQUILIBRIA in the reactions between gases and liquid metals have been the subject of many interesting investigations. The experimental realization of true equilibrium, however, is questionable in certain cases due to the lack of conclusive studies in reaction rates. It -will be shown here that a systematic interpretation of rate studies with the analysis of prevailing experimental conditions leads to valuable practical information. The reactions of particular interest are: H2(g) +S(inFe) - H2S(g) [1] H2(g) +O (inFe) =H2O(g) [21 2H2(g) + SiO2(s) = 2H2O(g) + - (inFe) [3] The usual and perhaps the most convenient method of investigation may be illustrated with reaction 1. A stream of gas mixture consisting of H2 + H2S is passed over or bubbled through the liquid metal at constant temperature. The ratio of H2S/H2 in the entrant mixture is fixed in each experimental run, and, therefore, the composition of melt varies until the establishment of equilibrium. The purpose of this paper is to derive a formula expressing the minimum time required for the establishment of equilibrium and to compare the calculated values from such a formula with the available data. Equations Reaction 1 is used for the purpose of illustrating the derivation. Let E represent the equilibrium and X the nonequilibrium sulphur in weight percent at any time t in minutes. For the sake of simplicity, it is first assumed that E > X although the results are of general applicability without restriction. It has been shown by Morris and Williams&apos; that within a difference of 1 pct S or less, i.e., E-X5 1.00, the value of K&apos;1 = Ph2s/Ph2.S% is very nearly constant. The maximum ratio of available Ph2s/Ph2 = H,S/H,, from which sulphur can be absorbed by metal, is equal to H2S/H2 in equilibrium with E (which equals H2S/H2 in the entrant gas), minus H,S/H, in equilibrium with X. Thus: Available H2S/H2 = EK&apos;1 - XK&apos;1 [4] Eq. 4 expresses that sulphur can be absorbed by metal from the H2S/H2 in the entrant gas until the gas leaving the metal assumes a value of H2S/H2 which is in equilibrium with the dissolved sulphur X at that time. H,S constitutes up to approximately 1 pct of the gas mixture. Its disassociation into H2 and SL is about 1 pct at 1600°C, hence, the H2S/H2 impinging on the surface of metal is very close to that in the entrant gas. The rate of flow of hydrogen entering the reaction chamber is kept constant experi-

Jan 1, 1954

By D. H. Polonis, M. B. Kasen

AN unusual thermal etching phenomenon has been observed on the surface of a Cu-Si alloy. The observations were made during studies of vacancy condensation pit formation which were reported in previous papers.1,2 Figs. 1 and 2 are photomicrographs of the surface of a Cu-4.8 pct Si alloy after heating in vacuo (3 x X mm Hg) to 525°C and subsequently holding at that temperature for 16 hr in an impure (air-contaminated) argon atmosphere. Under these conditions preferential removal of silicon from the matrix by oxidation results in a surface which is entirely a phase overlying an a plus y structure. The light areas of Fig. 1 are regions in which very little thermal etching has occurred, while the majority of the surface has experienced severe etching. Similar regions in Fig. 2 are seen as plateaus above contours produced by net transfer of material from the specimen surface. Twin boundaries are also visible in Fig. 2. The difference in matrix mi-crostructure between Figs. l and 2 reflects the par- ticular orientation of low-index planes with respect to the surface of observation. Thermal etching contours of this type have been studied in detail by Hondros and Moore Both of the photomicrographs show that one or more dark spots are located approximately at the center of every protected area; where two spots are in close proximity, the protected areas have merged. The microstructures indicate that the anomalous resistance to thermal etching is related to the presence of these spots. Williams and Hayfield have shown that local regions of unusually high oxidation resistance can be caused by a surface monolayer of atoms with a work function higher than that of the base material. The result is an inhibition of the rate of electron removal from the base material and a decrease in the oxidation rate. The source of the protected layer may be either surface diffusion from contaminants on the specimen surface or pipe diffusion of solute atoms followed by migration across the surface. In the latter case the driving force is a difference in chemical potential resulting in a Gibbs adsorption phenomenon. In the present case, chemical polishing of the specimen surface precluded contaminants of a strictly surface nature. Consequently, diffusion of impurity atoms from within the lattice appears to be the most tenable explanation of the observed phenomena. The authors propose that the structures of Figs. 1 and 2 reflect the diffusion of impurity atoms along extended dislocations within the individual a phase grains prior to surface oxidation. The central spots within the protected regions are seen as sites of dislocation emergence which have become locally decorated with oxide in the manner discussed in Ref. 1. Williams and Hayfield observed protected regions adjacent to the grain boundaries of iron-contaminated copper which they attributed to the segregation of iron to the grain boundaries coupled with high dif-fusivity along the complex dislocation array at such boundaries. No evidence of such grain boundary protection was observed in the Cu-Si alloy; this

Jan 1, 1964

By C. P. Besse, N. F. LeBlanc

Described in this paper are oceanographic data which should be considered by an offshore design engineer and methods for developing a design wave height from the oceanographic data. The selection of a design wave is predicated on contemplated waves which might affect the site throughout the life of the structure. Selection of a design wave height may be based on (1) arbitrarily established recurrence Frequencies of hurricanes affecting the structure (predicted wave heights are associated with the expected variations of forces resulting from these waves) and (2) a risk-type evaluation wherein all possible storms affecting the area are considered (anticipated wave heights are associated with both investment plus risk costs and expected variations of forces). It is shown how the following oceanographic predictions are integrated into design considerations: (1) a classification of storm intensity which considers all recorded storms which affected the design area, (2) the recurrence interval of storms of a given- intensity (this interval is dependent on the extent of the geographical area considered in the design problem) and (3) a forecast of all wave heights which might affect the area (geometry of a structure often necessitates consideration of waves from a multiplicity of directions). The authors believe that the described techniques can result in selecting an adequate and reasonable design wave. INTRODUCTION Since the inception of offshore operations in the Gulf of Mexico, engineers engaged in designing suuctural facilities have been plagued with the problem of selecting an adequate and reasonable design wave. In the development of any offshore structure it is mandatory that the engineer evaluate the ability of the structure to withstand the ocean waves to which it will be subjected. Selecting such design waves quite naturally necessitates a coalition of the oceanographer and the design engineer. The oceanographer must provide a detailed knowledge of scientific principles which govern the behavior of waters in the Gulf of Mexico. He should also have an adequate knowledge of the manner in which design waves are utilized by the engineer. Although the design engineer&apos;s primary responsibility is applying the oceanographer&apos;s specialized knowledge in the creation of real structures, it is important that he possess some knowledge of related oceanographic principles to reasonably evaluate and apply the recommendations of the oceanographer. In the Gulf of Mexico it is the hurricane wind waves which generally govern the design of an offshore facility. The oceanographer must therefore develop techniques for predicting the heights, periods and frequency of all hurricane waves which might affect a particular structure. From this mass of oceanographic data, the design engineer must select the design waves which will apply to his particular design. PAST STUDIES ON FREQUENCY AND AMPLITUDE OF HURRICANE WIND WAVES Past oceanographic studies on the frequency of hurricane wave heights in the Gulf of Mexico have been devoted largely to predicting the recurrence interval of hurricanes which will generate maximum significant waves of given heights. The maximum significant wave height is the average height of the highest one third of the waves in that portion of the storm producing maximum wave heights. Since these waves occur over a relatively small portion of the storm (Fig. 1) and since the paths of hurricanes vary considerably (Fig. 2), the recurrence frequency of such heights is largely a function of the extent of the geographical area considered. In establishing the frequency of maximum significant waves for the entire American Gulf coast, the major fully developed hurricanes which affected the coastline from BrOwnsville, Tex., to Key West, Fla., were considered (Fig. 2). These Storms were selected and described by C. L-