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By Blake M. Loring

RECENTLY the S-curves for 30 to 40 alloy steels have been published.1,2 These steels show individual characteristics, which make each additional S-curve of great interest. There are important differences in the mechanism of the transformation process, the type of transformation product, and the influence of alloying elements. Steels of the same general alloy composition may possess such variable characteristics with regard to the length of time of isothermal transformation that an S-curve for each heat of steel may be desirable. In the present work the isothermal transformation of a steel having the following composition and grain size was studied: 0.20 percent carbon; 0.21 manganese; 0.026 phosphorus; 0.017 sulphur; 0.056 silicon; 1.45 chromium; 3.25 nickel; austenite grain size, 7. The progress of the isothermal transformation was followed by several different methods, including hardness measurements, dilatometer observations, and examinations of the microstructure. It was not expected that these methods would be in precise agreement.3 Accordingly, the changes in microstructure and hardness were given additional weight in determining the initial stage of transformation and the dilatometer measurements were relied on in estimating the completion of the process. The beginning of transformation was indicated by I per cent of transformation products and the end of transformation by about 99 per cent. The reproducibility of the various methods in the ranges of highest sensitivity was checked by several observations at each time and temperature. The steel used in this investigation was annealed for 24 hr. at 925°C. Macroetching revealed no serious segregation. The specimens for the metallographic and hardness investigations were 1 1/4 by 1/2 by 1/8 in. Wires attached to the samples were used for handling, instead of tongs, to avoid chilling. The specimens were heated at 845°C. for 1/2 hr. and quenched into constant-temperature salt baths held at various temperatures from 205° to 650°C. The time required to transfer the specimens was found to be about x 1 1/2 sec., and nearly 5 sec. more was required for them to come to the temperature of the bath. After various lengths of time in the constant-temperature baths the specimens were quenched in water at 21°C. The specimens were cut in half for the metallographic examination, to provide a surface free from decarburization. To determine the beginning and end of the transformation the percentage of transformation determined metallographically and by hardness was plotted against time. A planimeter was used in the metallographic determination. The hardness and metallographic determinations made at room temperature were confirmed reasonably well by dilatometer measurements taken during the process of transformation at the various temperatures. Two dilatometers were used to

Jan 1, 1941

By Charles Hart

THE art of electric smelting came with the turn of the present century and owes its existence to the introduction of alter-nating current, which found its first wide use in the establishment of the great power plants at Niagara Falls, N, Y. Prior to that time current was largely direct. The fur-naces were electrolytic in nature and found their first metallurgical use in the produc-tion of aluminum, and this process still prevails. The normal production of pig iron up to that time was carried on in blast furnaces in which charcoal, coke and anthracite were used as the fuel. This new electric process called for sufficient carbonaceous material to reduce the oxides and impregnate the pig iron with sufficient carbon, but the remainder of the energy was to be supplied by electric power. The chemical reactions are essentially the same in electric smelting as obtains in the older blast furnace. All of these data are so well known in both methods as to need no discussion at this time, for they can be found in scientific publications and books written during the first two decades of this century.

Jan 1, 1940

By C. S. Smith, E. W. Palmer

IN 1934, when Gregg and Daniloffl wrote their excellent monograph on the alloys of iron and copper, the most recent literature on the constitution of the alloys indicated a narrow single-liquid area for 20" above the liquidus with a closed liquid mis-cibility gap above this. Since that time, however, a number of investigators have confirmed the much earlier studies of Mushet2 and Stead3 who, among others in the nineteenth century, had described the true state of affairs. Liquid copper and iron are completely miscible in the absence of carbon, but small amounts of carbon cause liquid segregation. In 1934, one of the writers' mentioned evidence for the absence of liquid separation in carbon-free alloys at temperatures up to 1700°C. Two years later, Mad-docks and Claussen5 unequivocally established the absence of liquid segregation and published a revised diagram, reproduced in fig. 1. They also studied the limits of the two-liquid area in ternary alloys of iron, copper, and carbon as a function of carbon and iron content. In the same year Simpson and Bannister" and Schumacher and Souden7 described in some detail the properties of alloys containing 50 to 75 pct Cu. More recently Hodges et al.16 have developed the copper-rich alloys for use as high-strength conductors. In 1937, Iwase, Okamoto, and Ameniya8 published data on the miscibility gap in ternary alloys of iron, copper, and carbon that supported the conclusions of Maddocks and Claussen, and definitely located the two-liquid area at temperatures of 1450" and 1540°C. They also reported that additions of 1 pct Al, Ni, Pb, Sn, or Zn caused no segregation in 50 pct Cu alloys at 1540°C. The use of copper in amounts approximating 1 pct has found industrial employment to an increasing degree in both wrought and cast steels, for such steels are capable of being precipitation-hardened following normalizing, and have high yield strengths. This is summarized by Gregg and Daniloff,1 Sallitt,9 and Lorig and Adams,10 while Alexander" gives additional information on the heat treatment of copper-steel castings. Lippert12 has described Digby's two-phase steels containing copper and chromium. The work described in the present paper was done in the years 1932 to 1934, at which time much of the information was new. The excellent work subsequently done in other laboratories but more promptly published makes the present paper in part only a confirmation of what is now well known. There has not, however, been published any unified study of

Jan 1, 1951

By J. R. Jargon, H. K. van Poollen

Non-Newtonian fluids may be injected into a reservoir during secondary recovery operations. The non-Newtonian fluid used in this work is a power-law type of fluid that is, the viscosity of the fluid decreases as the flow rate or rate of shear increases. This paper presents equations for steady-state linear and radial flow of such fluids, transient behavior results from a finite difference model of a radial system, and transient behavior results from a field test. The equations that describe the flow of a non-Newtonian fluid are non-linear and are solved numerically. Finite difference solutions are presented as curves of dimensionless pressure drop at the wellbore us dimensionless time for a constant injection rate. Solutions were obtained for 5-percent, 10-percent and 100-percent PV of a non-Newtonian fluid for injection rates of 1, 10, 100 and 1000 cc/sec and for a 5 percent PV of non-Newtonian fluid located at T = Tw' 3, 10, 20, 50 and 100 ft for a flow rate of 1 cc/sec. The buildup curves do not exhibit a stmight-line portion as is the case for Newtonian flow through porous media. Correlations also are shown for the productivity index vs rate for the computer model study and the field tests. INTRODUCTION During various secondary recovery operations non-Newtonian fluids are injected. Such fluids, in general, include thickened water and gelled fluids. The term "non-Newtonian" implies that the viscosity is not only dependent upon temperature and pressure, but also on the rate of shear that is applied to the fluid. For example, water, which is a Newtonian fluid, will have essentially the same viscosity no matter what rate of shear is applied. A pseudo-plastic fluid exhibits a decreasing viscosity when higher rates of shear are applied; a dilated fluid has an increasing viscosity with increasing rates of shear. The objective of studies performed and described in this report is to obtain relationships and mathematical and empirical descriptions of the flow of non-Newtonian fluids through porous media. Simple mathematical relationships, computer studies that include the unsteady-state behavior of such fluids, and field tests are used. PREVIOUS LABORATORY STUDIES Laboratory studies have been performed by several investigators. The fluids used in one investigationl were surfactant-stabilized dispersions of water in hydrocarbons. Its Fig. 6 is reproduced as our Fig. 1. This effective-viscosity vs frontal-velocity diagram shows that this fluid is of the power-law type over a fairly large range of frontal velocities. Gogartyl developed an equation for the effective viscosity as a function of shear rate that reduces to Eq. 2 for frontal velocities greater than about 2 ft/D. The fluid characteristics used in the present study are similar to those reported by Gogarty. Christopher and Middleman2 performed experiments with power-law fluids flowing through pipes packed with glass beads. They used a modified Blake-Koteny

Jan 1, 1970

By D. T. King

In coal preparation plants, as in many industrial operations where raw materials are handled, nuisance, health, and equipment maintenance problems arising from the generation of dust are inevitable. Devices for the control or collection of dust are therefore essential components of the plant process equipment. The objective of a dust collector is to separate solid particles from a gas stream in which they are suspended. Various types of devices can be employed to accomplish this end. The choice of the type of collecting device for a given application depends on principles of the behavior of fine particles and on factors associated with the properties of the dust (such as particle size, density, shape) and the suspending medium (such as density, humidity, viscosity, velocity). Particles suspended in a gas stream are acted upon by a number of forces including the buoyant force and frictional resistance of the suspending medium, which tend to keep the particles in suspension, and the force of gravity which tends to impart a relative motion between the particles and the fluid. The smaller the particle the greater the tendency for it to remain in suspension and, thus, the more difficult it becomes to collect the particle, or separate it from the fluid stream. To effect separation, therefore, some external force must be applied on the dust particle. When dust particles in a gas stream are acted upon by an external force, for example, gravity, centrifugal force, or an electrostatic field, the particles will be accelerated in the direction induced by the force. Because of a relative motion between the particles and the gas stream, a frictional resistance will be set up that will limit the velocity of the particle toward the force. To effect collection of the particles, this velocity must be great enough that the particles are trapped by some collection medium before the gas can transport the particles out of the collecting equipment. The most common physical mechanisms employed by collecting devices include gravity, inertial or centrifugal force, impingement, and electrostatic fields.

Jan 8, 1967

By Donald M. Liddell

From a commercial standpoint, the only beryllium mineral warranting attention is beryl, 3Be.Al2O3.6SiO2, which is of fairly widespread occurrence. The chief deposits are in Brazil, Argentina, India, Canada and Portugal. When pure this contains about 14 per cent of beryllium oxide. The mineral richest in beryllium is phenacite, (BeO)2SiO2, or beryllium orth-osilicate, which contains 45.55 per cent beryllium oxide when pure, and if anyone is ever fortunate enough to discover a large deposit of it, it will revolutionize beryllium metallurgy. Gadoljnite, zBe0.Fe0.2Yz0~.zSi0~, is also often referred to as a beryllium mineral, though the occurrences are comparatively scant and it is of more interest as a source of yttrium than it is of beryllium. There has been a good deal of talk recently regarding some occurrences of helvite in the United States. Helvite is a complex manganese-iron beryllium silicate and, apart from difficulties that would arise in its treatment because of its compo-sition, the beryllium content of the known deposits is not high. Early Metallurgy The elemcnt beryllium was first isolated by L. N. Vauquelin in 1797.~ He crushed and heated beryl, having the idea that this heating made it more readily amenable to attack by chemicals, and then mixed the mineral with three times its weight of caustic potash and fused the mixture. The melt after cooling was dissolved in hydrochloric acid: dehydrated, and again taken up with hydrochloric acid and filtered to separate the silica. The filtrate was treated with an excess of potassium carbonate and the precipitate after draining was leached with a solution of caustic potash, which dissolved the alumina. The undissolved material was, in Vauquelin's own words, "une terre nouvelle." He dissolved the precipitate with nitric acid and evaporated it to dryness, took up with hydrochloric acid and threw the iron out with potassium hydrosulphide, though he found that to make a complete separation of the iron involved a second treatment. The solution, after throwing out of the iron, had a pronounced sweet taste, and though Vauquelin always speaks of working on "terre du beril" he suggests that the new element should be known as "glucine" (glucinum) from the Greek word for sweet, because of this outstanding property. Vauquelin did considerable work on the comparison of aluminum and beryllium, working out a separation of most of the aluminum based on its precipitation as alum. His work is reviewed at some length, since ordinarily his procedure is incorrectly stated. It will also be recognized by those who have studied beryllium metallurgy that a good many technicians have followed his ideas since, including preheating the beryl before treatment. The fusion with

Jan 1, 1944

By Blair R. Benner

This paper describes the installation and operation of a Texas Nuclear on-line silica analyzer (NOLA) coupled with a Leeds and Northrup Microtrac particle-size monitor (Microtrac) at U.S. Steel's Minntac taconite concentrator. An automatic sampling system provides the NOLA with samples of final concentrate. After the sample is analyzed for silica by the NOLA, it is pumped to the Microtrac for size and surface area measurement. A sample is analyzed every six minutes, providing the control room with the silica concentration, the percent passing 270, 400, and 500 mesh, and an equivalent Blaine surface area number. When fed a slurry of final concentrate containing between 20 and 70% solids and 5 to 6% silica, the NOLA analysis is within ±0.2% of the wet chemistry silica. The agreement between the Microtrac output and standard screen analyses is ±1.2% at 270 mesh; ±1.5% at 400 mesh, and ±2% at 500 mesh. The poorer disagreement at the finer sizes is mainly due to inaccuracies in screening at 400 and 500 mesh. The agreement between Microtrac surface area a d laboratory Blaine surface area is about 9 ±80 cm 2/g. These instruments provide rapid and reliable feedback information to the concentrator and feed forward information to the agglomerator.

Jan 1, 1984

By M. J. Pool, C. E. Lundin

THE relative partial molar enthalpies of aluminum, gallium, and indium in liquid tin have been measured at 750°K by liquid-metal solution calorimetry. The measured heat effects and the calculated relative partial molar heats of solutions at infinite dilution are listed in Table I along with the relative heat contents of the solutes calculated from the data of Kelley. All of the values are referred to 750°K even though the calorimeter temperature fluctuated by +1°K during the entire series of experiments. The effect of this small temperature variation on the experimental values should be less than the experimental error. The limits of error given in Table I represent the standard deviations of all values from the mean. In no case was the experimental deviation greater than the listed error limits. The reported error estimates only apply to the estimated precision of experimental values and not to their accuracy. Systematic errors could be present in the calorimeter which would affect the absolute values given. Moreover the heat-content data used could also be in error and this would affect the end results. The relative enthalpies used were listed in Table I so that future corrections could be made if necessary. The relative partial molar heats of solutions of aluminum in liquid tin and dilute A1-Sn liquid solutions are large and positive. The value at infinite dilution is given in Table I. In the dilute-solution region investigated the relative partial molar heat of solution was a linear function of composition. A least-squares analysis of the data gave the following expression at 750°K: Atf^ = 6195 - 12,160 A:A1(cal/g-atom) where XA1 is the mole fraction of aluminum in the alloy. This can be compared with the data of Cohen, Howlett, and ever' who obtained the expression: 1SM = 6075 - 10,750 XM at 573°K Apparently both the partial molar heat of solution at infinite dilution and the concentration dependence increase with increasing temperature. This same

Jan 1, 1964

By A. R. Powell

Four, general methods have been used in the study of the decomposition of coal. The first has been directed toward the processes of coal formation, the second has been by means of microscopic studies, the third from the data of destructive distillation, and the fourth has made use of various solvents. Applying these methods to the sulfur of coal, it has been found that the organic sulfur of plant and animal life enters into the formation of coal and remains in organic combination in the final product. The inorganic sulfur is almost entirely combined as iron pyrites and marcasite. The infiltration of hydrogen-sulfide waters is doubtless a large factor in these combinations. Sulfates are found in very small quantities except where free oxygen has entered the coal strata. The mechanical mixing of detritus with the early coal material is another source of sulfur. In this case the sulfur is distributed in microscopic particles throughout the mass. In destructive distillation, a part off the sulfur comes off as hydrogen sulfide and various thiophen compounds, but this furnishes little information as to the nature of the sulfur compounds in the coal itself. The use of solvents has given valuable data concerning the sulfur compounds in coal. Fremy1 and later E. Guignet2 noted the action of alkaline solutions on coal after treatment with nitric acid and Anderson and Roberts3 showed' the presence of large quantities of organic' sulfur in the extract so obtained. In a study of the phenol extract of coal, Parr and Hadley4 found organic sulfur in the soluble organic material. These investigations proved the presence of organic sulfur in coal in addition to the inorganic forms, such as iron pyrites and sulfates. T. M. Drown5

Jan 9, 1919

THE National Coal Association held its annual meeting at Cleveland on Nov. 14-16, 1928, having changed the time from the spring to the autumn to avoid conflict with the great number of meetings ordinarily held in the spring. Institute members were \\yell to the fore in its activities, the president, E. C. Mahan (who was reelected for another term!, C. E. Bockus, treasurer, and the secretary, H. L. Gancly, being A. I. M. E. members, as are many of the directors. At the first session, our past president, S. A. Taylor, presented a 1;aper which is reprinted in part herewith. At the Thurs- day session W. D. Brennan presided, Walter Barllum led the discussion on membership, and Otis Mouser led the discussion on taxation. In the afternoon, J. P. Williams, Jr., led the discussion on research. Rembrandt Peale presided at the annual dinner in the evening. At the concluding session on Friday resolutions were adopted, among them one in which the Association "reaffirms its attitude toward proposed Federal legislation affecting the bituminous coal industry by saying that it opposes legislation which would seek to single out this industry for regulatory action. This particularly applies to such bills as S4490."

Jan 1, 1928

By Nicholas J. Grant, Rolf Nordheim, Bill C. Gissen

The system Cb-Re was examined in detail utilizing pure metals, careful melting techniques, and heat treatments. Metallographic and X-my methods were utilized for phase identification. In addition to soli-dus determinations, the composition limits and mode of formation of the intermetallic compounds 0 and X were determined. The binary constitution diagram Cb-Re has been the subject of a number of investigations.'-7 Two intermetallic phases have been described and tentative diagrams have been proposed. It was the aim of this investigation to obtain a complete and more accurate diagram through the use of purer alloys and improved techniques. The diagram worked out by Knapton7 was published after our experiments were concluded. EXPERIMENTAL METHODS The starting materials were Re powder of 99.95 pct purity, supplied by the Chase Brass and Copper Co., and Cb rondelles of 99.6 pct purity, supplied by the Electro Metallurgical Co. Typical analyses are given in Table I. The alloys were prepared from compacted Re powder and Cb rondelles; for critical compositions master alloys were used. The melts varied from 5 to 50 g and were melted nonconsumably in an Heraeus arc furnace, under ti-tanium-gettered laboratory grade argon. It was necessary to invert the buttons and remelt, followed by crushing and further remeltings, the number of which depended on the nature of the fracture of the alloy. The weight of each alloy was carefully checked after each melting operation. It was found that significant weight losses occurred only when loose Re powder was used. These losses amounted to a maximum of 3 wt pct in such instances, but did not occur after the charge was once molten, regardless of the composition. Typical loss of weight after 4 remelts, including crushing, amounted to 0.2 wt pct. Oxygen pickup during successive melting cycles did not appear to be significant, since the weight gain values never exceeded 0.01 wt pct. Control of the composition of the alloys was not too difficult; however, the problem of homogenization was a far greater one. Optimum alloying conditions were finally achieved by a combination of master alloy production and repeated crushing and remelting cycles. The compositions of the alloys utilized to determine the constitution diagram are listed in Table 11. The weight balance method was used ultimately as the sole analytical method, since repeated checks indicated that it was accurate to 0.2 pct, if the weight losses were small. The results were double-checked by a metallographic study of the homogeneity of the samples, since this was presumed to be the more serious factor. Heat treatments at 1200°C or lower were accomplished by sealing the specimens in Vycor tubes, heating in a Globar furnace, followed by air cooling. This was considered to be an adequate quench because of the very low temperatures involved. For temperatures of 1200" to 1900°, alloys were homogenized and heat treated in a tungsten-filament resistance vacuum furnace. From 1900" to 2750" a tantalum-tube resistance furnace was utilized, operating under a vacuum of 105 mm Hg. The temperature measurements up to 1200" were made by means of platinum-platinum 10 pct Rh thermocouples, with an accuracy of 5°C. For temperature measurements greater than 1200°C, optical pyrometers were used. They were calibrated against a standardized instru-

Jan 1, 1962

By Claiborne C. Van Zandt

THE heavy postwar demand for Portland Cement has created shortages that are gradually being overcome by increases in plant capacity. In the post-war period, the Lone Star Cement Corp. has expanded several of its existing 15 plants and has built 2 new plants, now in operation, with a third new plant under construction in Brazil, of design somewhat different from that of the two preceding ones. The new domestic plants are located at Lone Star, Va., near Roanoke, and at Maryneal, Tex., near Sweetwater, and went into operation during 1951. Each plant is equipped with two rotary kilns and has an initial capacity of 1,500,000 bbl per year, or 6,000,000 sacks. The total cost of each plant was about $10,500,000, and on this basis $7.00 in 1951 money are required per bbl of annual capacity; at 376 lb per bbl, this corresponds to $37.00 per ton of output. The investment corresponds to approximately $80,000 per hourly-wage earner employed. The purpose of this paper is to describe the most interesting design features of the two new and almost identical Lone Star plants. Why the Dry Process Was Chosen The two new domestic Lone Star mills employ the dry process because: 1-The raw materials at both properties are particularly suitable and can be dried very, readily. 2-The Maryneal, Tex., plant does not have water available for slurry. 3-Very substantial kiln fuel savings can be obtained. 4-Dry raw grinding reduces ball and liner wear and- general maintenance, without any sacrifice in power. Operating costs to date have more than justified the choice of the dry process for these two plants. Raw Materials The chemical composition of Portland Cement raw material after crushing, grinding, and mixing, but before burning, is about as follows: [ ] sometimes tailings from an iron ore concentrating plant. Certain objectionable materials occur in raw mix: magnesia, limited in cement to 5 pct, in excessive amounts; alkalies, as sodium and potassium; phosphorous; and sulphur, generally present in coal and oil. The Roanoke raw, materials are dense limestone and shale. The Maryneal materials are soft limestone and a hard brittle clay that can be handled much like shale. Sand and iron ore are required in small quantities. General Plant Layout and Construction The two plants are so similar that one joint description will cover both, with such exceptions as will be especially indicated. The crushing plant is located in the quarry, and raw material is conveyed by belt to the storage building, where all materials are stored and handled. Fig. 1 identifies the various structures of the Roanoke plant. The large storage building is used for the storing and handling of all materials, including limestone, shale, sand, iron ore, coal, clinker, and gypsum. Directly adjoining the storage building is a structure under a similar arched roof, containing the raw and clinker grinding departments and the electrical substation. The discharge ends of kilns and coolers, and coal or gas burning equipment are also placed at one end of the mill building. The 340ft long kilns extend away from the main buildings to form the long leg of an L, at the end of which is the feeding and kiln dust collecting equipment, and the raw blending silos are conveniently located adjacent to the feed end of the kilns. The machine shop, storeroom, electrical shop, foremen's office, service rooms, and meeting hall are combined in one structure in the center of the plant, and the office and laboratory are close by. The cement silos and packhouse do not have to be tied directly into the manufacturing process and are therefore located at a point convenient to the railroad tracks.

Jan 1, 1952

By E. A. Elevatorski

Wollastonite, named after William H. Wollaston, an English chemist, is a calcium metasilicate, CaSiO3. It has a short history as an industrial mineral. The earliest production of wollastonite is reported to be from a deposit near Code Siding, located north of Randsburg, Calif. At this locality small tonnages of wollastonite were quarried during 1933-34 and 1938-41, and processed into mineral wool. This operation was largely experimental and virtually no United States production was again reported until the 1950s when a large deposit near Willsboro, N.Y., was developed by the Cabot Corp. A processing plant was placed on-stream in 1953, with nearly continuous production to date, and it is currently operated by Interpace Corp. Since 1958, wollastonite deposits in the Little and Big Maria Mountains of Riverside County, and in the Panamint Range of Inyo County, both in California, have operated intermittently for production of both ornamental and commercial wollastonite. During 1973, the United States was the major producing country, furnishing about 75% of the world's output. Recent production also has come from Finland, Mexico, and Kenya. Small amounts have been shipped intermittently from India, USSR, New Zealand, Republic of the Sudan, Republic of South Africa, and South-West Africa. The principal use of wollastonite is in the manufacture of ceramics, especially wall and floor tiles. Other uses are for paints, fillers, adhesives, reinforcing agents, plastics, fluxes, and glazes. Mineralogy Pure wollastonite, CaSiO3, has the composi¬tion of 48.3 % CaO and 51.7 % SiO,. However, it is seldom found in the pure state due to the ease with which it takes into solution the metasilicates of manganese, magnesium, iron, and strontium. Predominantly, wollastonite occurs as a contact metamorphic deposit forming between limestones and igneous rocks. Commonly associated minerals are garnet, diopside, epidote, calcite, and quartz. It has a specific gravity of 2.8 to 3.0, and hardness of 4.5 to 5 on Mobs' scale. When pure, it has a brilliant white color, but with impurities it may be grayish or brownish. Luster is vitreous to pearly. Melting point of wollastonite is about 1540° C. Wollastonite occurs in coarse-bladed masses, rarely showing good crystal form. It is usually acicular or fibrous, even in the smallest of particles. The most unique property of crushed and ground wollastonite is its cleavage. Fragments of crushed wollastonite tend to be needle-shaped, imparting a high strength, and this property is the basis for many of its uses. The fiber lengths are commonly in the ratio of 7 or 8 to 1, length to diameter. Some crystals of wollastonite fluoresce under short-wave or longwave ultraviolet light, or both; colors ranging from yellow-orange to pink-orange. Specimens may also show phosphorescence. The brightness of wollastonite is a property of considerable importance to the paint industry. Material, 99% pure, with a size of -325 mesh, has a General Electric reflectance rating of 92 to 96%. Chemically, wollastonite is inert and this property makes it useful as a filler and reinforcing agent. There are two polymorphs of calcium silicates: wollastonite, a low temperature form, and pseudowollastonite, a high temperature form. Inversion of wollastonite to pseudowollastonite occurs at about 1120° C, resulting in an increase in the coefficient of expansion and a color change. Pure white wollastonite, on inversion, may change to a cream tint, or various shades of red or brown. The color change is thought to be due to the presence of iron and strontium.

Jan 1, 1975

By G. S. Anderson

PRIOR to 1912 the only rail outlets for a large part of the coal regions of Carbon and Emery Counties. Utah, were over single-track lines of the Southern Utah R.R. and Castle Valley Ry. Companies, forming a route extending from Mohrland and Hiawatha, Utah, to a point of connection at Price, Utah, with what is now The Denver and Rio Grande Western R.R. Co. These two tap lines were poorly and inadequately constructed, with impracticable grades, lacking in equipment, and incapable of being put into condition to serve this region and handle the output of the mines, to say nothing of making possible increased production and new development. Any plans for the new development and increased output necessarily involved new and adequate railroad service. It was essential, not only that additional facilities be provided but that these facilities be in the form of an efficient and up-to-date railroad providing an independent through operation from the coal mines to a point of direct connection with the lines over which the product would be distributed to consumers. For this purpose, the Utah Railway Co. was incorporated in

Jan 1, 1948

By J. D. Hunt, D. T. J. Hurle

A uariety of eutectic structures are formed in faceted/nonfaceted eutectics. The various structures are explained in terms of the absence or presence of small facets in the liquid groove. Regular structures are produced when, for purely geometric reasons facels cannot form. The presence of a facet in the liquid groove leads to the formation of an irregular or a cell-like complex regular structure, due to the relative immobility of the groove. A classification of eutectics was proposed by Hunt and jackson, based on the presence or absence of facets on the primary phases (the absence of facets may be predicted from the dimensionless entropy of melting2). Eutectics were divided into three groups: 1) eutectics in which both phases grow in a nonfaceted manner; 2) eutectics in which one phase grows faceted, the other nonfaceted; 3) eutectics in which both phases grow faceted. It was suggested that regular1 rodlike or lamellar structures1 should be formed in the first group, that irregular or complex regular structures1 should be formed in the' second, and that irregular structures1 should be formed in the third. Recently it has been shown that the structural classification is incomplete. Regular rodlike structures (InSb-NiSb eutectic3), or broken lamellar structure (Bi-Zn eutectic, Fig. 8), are formed in alloys of the second group when the faceted phase has a large volume fraction. Hunt and jackson' argued that regular structures could form in faceted/nonfaceted systems, but that such structures would be unstable in the presence of microfacets on the lamella of the faceting phase, because the growth rate at a point on such a facet would depend on the kinetic undercooling at the point of nu-cleation on the facet, and not on the local kinetic undercooling. In these circumstances it would not be possible to consistently balance the compositional and kinetic undercooling over a lamellar structure and thus obtain a stable isothermal interface. In this paper we discuss in detail the origin of the various structures formed in faceted/nonfaceted systems, pointing out that the most important factor promoting the formation of a regular structure is the absence of a facet in the liquid groove. 1) FACET FORMATION IN SINGLE-PHASE MATERIALS Facets form when there is an energy barrier for the addition of a new solid layer on an existing solid. When a barrier is present,2 growth proceeds by the lateral movement of steps across a crystallographic plane. The rate-controlling stage of the process occurs when the step is first formed. Hulme and Mullin6 have shown that faceting in single-phase materials can only occur when both interface curvatures are convex with respect to the solid and when the surface is tangential to the facet plane. When even one of the curvatures is concave a facet does not form because new layers of solid from adjacent regions can always feed the facet plane, Fig. 1. Growth under these conditions is then as easy as elsewhere. Similar considerations will apply to eutectic growth; consequently the shape of the faceted phase is extremely important. 2) LAMELLAR SPACING CHANGES IN EUTECTICS Jackson and Hunt7 have shown that the interface undercooling AT of a growing lamellar interface (neglecting kinetic undercooling) is related to the lamellar spacing, A, and growth velocity, v, by an expression of the form: where m, Ql, and nL are constants of the system given in Ref. 7. Eq. [I] is plotted for fixed v in Fig. 2. Jackson and Hunt postulate that a regular eutectic grows near, but to the right of the minimum in the AT vs A curve. They argue that the spacing cannot be to the left of the minimum because the interface is then unstable to fluctuations in A. It cannot grow too far to the right, because when the spacing becomes too wide an isothermal interface can no longer be maintained over the large-volume-fraction phase.7 It is argued that during any change in growth rate the lamellar spacing remains in the permitted range by the movement of lamellar faults. When the spacing is too wide, the fault, shown in Fig. 3, moves to the left; when the spacing is too narrow it moves to the right. The faults, however, have to be formed. heir formation has been shown to occur when local regions deviate considerably from the spacing defined by the lamellar When the spacing is locally too narrow (it passes to the left of the minimum, Fig. 2), pinching off of the narrow phase occurs. When the spacing is locally too wide, the interface on the large volume-fraction phase can no longer be maintained as an iso-

Jan 1, 1969

By T. L. Loucks, E. T. Guerrero

Pressure drop characteristics in a system composed of two adjacent concentric regions of different permeability were studied. The differential equations for continuity of mass flow in the two regions were solved using the Laplace transformation and the necessary boundary conditions to give the pressure distribution in the composite reservoir, the resulting equation for pressure drop at the inner boundary was evaluated for a variety of composite reservoirs and compared with the results for a uniform reservoir. From this study it was found that under certain conditions the permeability in both zones, as well as the size of the inner zone, can be determined from the pressure drop curve. INTRODUCTION The theory for the pressure distribution and pressure build-up behavior of a well producing a single, slightly compressible fluid from infinite and finite homogeneous reservoirs was presented by Hornerl and Miller, Dyes and Hutchinson.2 Extensions on this original work to provide improved and extended interpretations and better agreement between theory and observed results have been made by Matthews, et a1,3 van Everdingen,4 Gladfelter, et al5 Stegemeierand Matthews,6 Hurst and Guerrero,7 and Perrine.8 More recently Lefkovits, et al,9 studied pressure build-up behavior in bounded reservoirs composed of stratified layers. Houpeurtl0 has suggested various approaches to the general problem of variable permeability and porosity but presented no analytic solutions for particular permeability variations. Albert, Jaisson and Marionll studied the finite composite reservoir and presented numerical solutions to the unsteady-state case and an analytical solution valid only for large times. They also studied the so-called pseudo-steady state for several examples of radial permeability variations. Very similar examples have been treated in the unsteady state with application to pressure build-up by Loucks in an unpublished manuscript. More recently Hurst12 has presented the complete point-sink solution (valid for all times) for the infinite composite reservoir. He applied these solutions to interference between oil fields along with an even more elegant application of his explicit solution to the material-balance equation including water influx. Mortada 13 approaches the same application by avoiding the point-source limitation but gives the solution for the aquifer region which is valid only for large times. Hopkinson, Natanson and Temple14 have treated both the finite and infinite composite reservoir obtaining the pressure distribution for the inner zone valid for large times. This paper presents a theoretical study of the pressure distribution in an infinite composite reservoir composed of two adjacent concentric regions of different permeability. The object was to determine the manner in which pressure drop at the inner boundary of a composite reservoir depends upon time, the permeability of each zone and the size of the inner zone. Expressions for the pressure distribution in both zones are developed which take into account the radius of the sink and are valid for small times as well as large times. It was felt that an understanding of the pressure drop behavior in various composite reservoirs would be of assistance in the interpretation of some pressure build-up curves which do not behave according to the theory derived for uniform systems. Often the region surrounding the wellbore is either more permeable or less permeable than the reservoir because of the various drilling and completion practices. The effects of reduced permeability due to drilling-fluid invasion and of increased permeability due to fracturing or acidizing need to be more carefully defined. Therefore, an equation for the pressure drop in a composite reservoir was developed, and the effects of both the permeability in each zone and the size of the inner zone were studied. STATEMENT AND SOLUTION OF PROBLEM BOUNDARY CONDITIONS AND ASSUMPTIONS The physical system studied was a composite

By W. R. Roser, F. E. Rizzo, Wu Hu

An insight into the mechanism of electrocrystallization of copper in simulated commercial acid electrolytes has been surmised from scanning electron microscope analysis of laboratory prepared specimens. The growth takes place in three overlapping stages. In he first, lasting approximately one hour at 200 amps/sq m, a propensity to epitaxial growth is observed. During the second stage a preferred orientation developed. The crystallography of the deposit showed a strong preferred orientation with the [111] direction normal to the surface. Triangular pyramids with (111) faces and (111) texture is a common result. In the third stage, occuring at longer deposition times, side growth, dendrite-like branching is common. The obsermtions have some elements in common with published results for highly purified electrolytes. Several significant differences were observed. The truncated pyramidal and block type growth discussed in he literature is suppressed under the conditions studied. The results are briefly discussed in terms of the screw dislocation, fault, and layer type growth mechanisms of crystal growth.

Jan 1, 1973

By Harvey P. Knudsen, Young C. Kim

This paper illustrates the application of geostatistics to a roll front type uranium deposit located in Wyoming. The steps involved in calculation of experimental variograms, variogram modeling, and verification of the resulting models are described in detail. The resulting spherical variogram models for grade thickness and thickness show strong geometrical anisotropies. The major axis of anisotropy for both variables is approximately parallel to the axis of the roll front and the minor axis perpendicular to the roll. This model confirms the technique of drilling "fences" across the roll front, where the drilling is much closer together than the fences along the roll.

Jan 8, 1979

There were present eleven Directors, the Secretary and Assistant Secretary of the Institute, and eleven guests. The Secretary, Bradley Stoughton, was appointed the representative of the Institute on the Board of. Directors of the American Bureau of Welding. A communication from a member of the Institute regarding simplified spelling was laid on the table. The following appropriations were made for the year. 1919: $250 to the Institute of Metals Division, $250 to the St. Louis Section, $100 to the Columbia Section. An invitation was received from the Western Society of Engineers to the Institute to use the facilities of that society during the A. I. M. E. Meeting in Chicago. The Bulletin of the Institute was presented to the French Congress of Engineers. There were elected twenty-eight members, eighteen associates, and three junior associates. The status of one member was changed from junior associate to associate. Four members were reinstated. An extension of time was granted to one member for payment of dues. The dues of four members on active military duty were suspended. Dues were remitted of four members who have been paying over thirty years, and who are each over seventy years of age.

Jan 5, 1919

The following paragraphs have been extracted from a recent publication of the U. S. Department of Commerce; Miscellaneous Series, No. 65, " German Trade' and the War, " which portrays the industrial, commercial and economic conditions of Germany, at the present time, and has been compiled largely from sources published in Germany. Iron and Steel The Krupp company, the greatest of the German munition works, was faced at the outbreak of the War with the disappearance of its great international business, but this was amply compensated by orders from Germany and her allies, and the activity of the company has been greatly extended. The general meeting of December 1914, voted an increase in the capital to 250,000,000 marks. The gross profits of the company, amounting to 61,900,000 marks in 1912-13, have been more than doubled during the war. The gross profits were 128,260,000 marks in 1914-15 and 143,360,000 in 1915-16. Large sums have been written off; 10,000,000 marks have been placed in the pension fund during the war, and 5,000,000 were appropriated for workmen's dwellings in 1915. Thirteen million marks have been devoted to war assistance in the last three years. The assets of the company were valued at 967,000,000 marks at the end of 1916. For the year 1916-17, the company paid a dividend of only 10 per cent., but set aside 85,425,000 marks for depreciation. The Bismarckhütte in Upper Silesia, capitalized at 16,000,000 marks, with a bonded indebtedness of 7,907,500 marks in 1913-14, reported 3,912,000 marks of net revenue from operation for that year. During the three years of war the revenue increased successively to 8,077,000, 11,805,000, and 16,994,000 marks. While the capital remained unchanged, and the bonded indebtedness was but slightly reduced, the dividends paid during the last four years were increased from 9 per cent. in 1913-14 to 15, 25, and 30 per cent. during the war. During the year 1916-17 the amount written off, chiefly on the works and plant account, was 10,553,000 marks, or nearly as much as the total set aside during the three preceding years. The turnover for that year reached a sum many times the amount of the capital. At the end of 1916 the company's shares were quoted at 275, as against 144 at the end of 1913.

Jan 8, 1918