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By J. H. Hensley

The mine of the Miami Copper Co. is in the Miami district, Gila County, Ariz., approximately 7 miles west of Globe. In 1906, the General Development Co. secured the ground now owned by the Miami Copper Co., and about a year later discovered ore in a prospect shaft at a depth of 220 ft. The Miami Copper Co. was organized in 1907, the claims held by the General Development Co. were transferred to it, and an active development campaign was inaugurated. The railroad was extended from Globe to Miami in 1909, a concentrating plant was constructed, and the company began producing early in 1911. The unit size of mineral tract in the district is the standard lode claim 600 ft. in width by 1500 ft. in length. Ownerships of land are held in fee. The geology of the district has been described by F. L. Ransome.' The formations of local importance are: The pre-Cambrian Pinal schist, which consists mainly of metamorphosed sedimentary rocks and is commonly of a thinly laminated sericitic variety; the diabase, which is thought to have been intruded in late Paleozoic or early Mesozoic times; the Schultze granite and granite porphyry, considered early Tertiary; the dacite of late Tertiary time; and the Gila conglomerate of early Quaternary. General Items Influencing Mining Methods The bodies of disseminated ore in the district are flat lying masses of irregular outline and variable thickness. As a rule, these masses lack definite boundaries; the orebody follows a curve along one of the main ridges, approximately 5500 ft. in length with a maximum width of 1600 ft. The minerals occur as finely divided and uniformly disseminated chal-cocite in the Pinal schist and Schultze granite. The typical overburden or capping is a barren rusty brown, very friable, highly siliceous, leached schist, or granite-porphyry. The topography of the district is fairly rugged and irregular; the altitude ranges from 3400 ft. above sea level, at the town of Miami, to 3900 ft. on the hills above the Miami orebody. The climate is mild; the mean annual temperature is 63.°F.

Jan 1, 1925

By E. C. Burke, W. R. Hibbard

G. B. Craig (University of Toronto, Toronto, O,nt., Canada)—The advent of pyramidal slip at room temperatures in a magnesium crystal (M2,) and the very low value reported for the critical shear stress are puzzling. Table I1 shows the calculated values (approximate) for sin x cos I in this specimen if all the (10l) planes are considered. If So is the shear stress resolved in the direction of glide, on the glide plane, and U, is the stress operative in yield point tests, then: S,, — 325 (0.169) 55gpersqmm (approximately) for 1101: S,, = 325 (0.465) = 151 gpersqmm (approximately) for (0001): S,, — 325 (0.101) - 32.8 gpersqmm (approximately) Thus, we see the pyramidal plane in which the minimum shearing component operated. Barrett"' stated: "Experiments have repeatedly shown that, when there are several crystallographically equivalent slip systems in a crystal, the one having the greatest resolved shear stress will become active. ..." It does not appear to me that the measurements given are conclusive proof that pyramidal slip operated. E. C. Burke and W. R. Hibbard, Jr. (authors' reply) —Although the low value for the critical resolved shear stress for pyramidal slip may be puzzling, there does not appear to be any basis for questioning the validity of the measurements. Under the influence of constraints, slip systems having decidedly lower shearing components may become operative, e.g., "cross-slip" or the "forced glide" in magnesium reported by Bakarian. Since we believe that pyramidal slip occurred in the specimen because basal slip was inhibited, it is not too surprising to find an operative plane with a lower shear stress. -7 C. S. Barrett: Structure of Metals U94jl p. 2J6. New York. McGraw-Hill Book Co.

Jan 1, 1953

By T. B. Massalski, H. W. King

An hcp phase may be induced by cold working the ß&apos; phase of the Ag-Zn system. This phase reverts to ß&apos; on subsequent aging. No phase change occurs on cold working the o phase, but ß&apos; is formed when the deformed alloy is subsequently aged at room temperature. It is concluded that for alloys near 50 at pct Zn the ordered bcc ß&apos; phase is the equilibrium structure at room temperature. WhEN the disordered bcc ß phase of the Ag-Zn system is cooled to temperatures below 258o to 274oC, it transforms to a complex hexagonal phase <o.1,2 The nature of the o ß=o transformation has been the subject of some discussion,2&apos;3 and the structure of o has been described in detail.&apos; The latter phase appears to be stable on aging at room temperature but decomposes following cold work. When alloys containing approximately 50 at. pct Zn are rapidly quenched from the 0 phase field, the ß ? o transformation may be suppressed; but the ß phase undergoes an ordering reaction (ß ? ß&apos;). The ß&apos; structure may also be obtained as a result of cold working and aging at room temperature.4 Kitchingman, Hall, and Buckley4 have suggested that the decomposition of (o following cold work proceeds in two stages, (o ? ß followed by ß ? ß&apos;, but did not confirm this by experiment. When the ordered &apos; phases in the systems Cu-Zn5 and Ag-Cd6 are cold worked, they become unstable and transform to a close-packed hexagonal phase (( ) indicating that when order is destroyed in a ß&apos; structure the close-packed hexagonal phase may in many cases be more stable. It thus became of interest to study more closely the effect of cold work and annealing on the stability of both the ß&apos; and o phases in a Ag-50 at. pct Zn alloy. Predetermined weights of spectroscopically-pure Ag and Zn, supplied by Johnson and Matthey, were melted and cast under 1/2 atm of He in transparent vycor tubing. The ingot was homogenized for 1 week at 630°C and quenched into iced brine. Since mechanical polishing was found to induce a phase change, sections were first polished at room temperature, sealed in tubes under 1/2 atm of He, reannealed for several days at 630o or 200°C and then quenched into iced brine. Sections of the alloy thus prepared were found to be homogeneous when examined under the microscope. The sample quenched from 630°C (ß -phase region) was pink in color, whereas the sample quenched from 200°C (o-phase region) was silver. The latter sample showed the characteristic hexagonal anisotropy when examined under polarized light. Filings of the alloy were examined at room temperature, after various heat treatments, using an RCA-Siemens Crystalloflex IV diffractometer with filtered CuKa radiation. The X-ray reflections from flat powder specimens quenched from 630o and 200°C and sieved through 230 mesh were recorded graphically at a scanning speed of 1/2 deg per min. The resultant patterns are shown in Figs. 1(a) and 1(b) and may be identified as those of the 8&apos; and <02 structures respectively. The lattice parameter of the ß&apos; phase was determined as 3.1566Å.* This value compares very well withthatto be expected for a 50 at. pct Zn alloy from the data of Owen and Edmunds? and indicates that no loss of Zn occurred during casting. In order to study the effect of cold work upon the ß&apos; and o phases, filings made at room temperature and sieved through 230 mesh were mounted immediately in the diffractometer-i.e., without a strain-relief anneal. Changes in structure on subsequent aging were followed by scanning repeatedly over the regions of the low index reflections of the ß&apos; and o structures-i.e. , 28 from 35 to 44 deg. Immediately after filing the 8&apos; specimen, additional diffraction peaks were observed in the low-index region of the pattern, as shown in Fig. 1(c). These additional peaks do not coincide with those of the o structure, Fig. l(b), but may be indexed as the (10.0), (00.2), and (10.1) reflections of an hcp phase (<) with nearly ideal axial ratio. However, this hexagonal phase appears to be very unstable since within a very short time at room temperature it reverts back to the ordered ß&apos; phase, the reversion being complete within seven hours. The 5 ? ß&apos; reversion reaction is, therefore, very similar to those already reported in Cu-Zn5 and Ag-Cd6 7&apos;alloys. The action of filing caused the deformed surface of the originally pink ingot to become silver in color, indi-cating that the ( phase possesses similar reflecting properties to the o phase. Hence, the subsequent

Jan 1, 1962

By G. K. Engelhart

A multi-stage counterflow process developed in Germany preheats dry pulverized portland cement raw materials held in suspension in rotary kiln waste gases. Capacity of the first kiln installed for this purpose in the United States has been increased from 860 to 1500 bbl per day, with fuel reductions from 1,100,000 Btu to 650,000 or 700,000 Btu per bbl. Sixty percent of total waste gas is used. As full use of the gas stream is approached, additional kiln production and fuel economy may be expected. EFFECTIVE use of rotary kiln waste gases to preheat dry pulverized materials has been demonstrated in full-scale operation at the Allentown Portland Cement Co. plant, Evansville, Pa. Pulverized raw materials are preheated in suspension in the gas stream in a multi-stage counterflow process which draws the gases through a series of cyclone collectors. Upon entering the first cyclone stage the material, continuously delivered and suspended in the gas stream, is successively collected and re-suspended until it discharges through the kiln feed pipe. Gas and material contact time is thus prolonged, providing a high degree of heat recuperation with a very low temperature differential between gas and material at the final stage. The suspension preheater, developed by Klock-ner-Humboldt-Deutz AG of Cologne, Germany, was first installed at the Norddeutsche Huette plant, Oslebshausen, Germany. Similar preheaters are now in operation at three other German cement plants. The first American installation, at the Allentown Portland Cement Co. plant, was designed and manufactured by Fuller Co. of Catasauqua, Pa., Humboldt&apos;s licensee for the United States, Canada, and Mexico. Design of this installation is essentially the same as the German original, but provision was made for varying the method to adapt the process to specific objectives of American portland cement production. Differences between German and American cement clinker production practices are directly related to differences in three primary production cost items: fuel, labor, and power. Because fuel costs are high in Germany and elsewhere in Europe, thermal efficiency has been the first objective of European cement producers and manufacturers of rotary kilns. The Germans have developed such recuperative equipment as the present suspension preheater, the Miag calcinator, and the Lepol kiln, the invention of 0. G. Lellep. In North America labor is the principal cost item, although rising fuel costs are of growing concern. High clinker production is therefore of first importance. Recent installations of longer dry process cement kilns have been disappointing, failing to make satisfactory reductions in exit gas temperatures when production is held at an acceptable level. The Humboldt suspension preheater satisfies both

Jan 1, 1955

By W. G. Pfann

Under certain conditions, a molten zone can be made to move through a solid by impressing a stationary temperature gradient across the solid. This phenomenon can be utilized in fabricating semiconductive devices, growing single crystals, joining, boring fine holes in solids, measuring diffusivities in liquids, small scale alloying, and purification. Fundamentals and exemplary applications are outlined. ANEW aspect of the travel of a molten zone through a solid is considered in this paper. Whereas, in previously described zone melting techniques,&apos;-&apos; zones were usually caused to move by changing the position or temperature of a heat source, in the present technique a zone is made to move by impressing a temperature gradient across it. For example, a thin layer of molten A1-Si alloy, sandwiched between two silicon slabs having a temperature gradient normal to the layer, will travel through the hotter slab. One feature of temperature gradient zone melting, as this technique will be called here, is that zones of unusually small dimensions can be maintained. This leads to such diverse uses as have been listed in the abstract. In this paper fundamentals of the movement of a molten zone in a temperature gradient, and some practical applications thereof, are outlined. Assumptions The movement of a molten zone through a solid body of solvent substance in which a temperature gradient exists will be discussed. The length of the zone will be its dimension in the direction of motion. The direction of the temperature gradient will be toward the region of higher temperature. To be considered is a binary or higher order solute-solvent system in which the concentration of solute in the molten zone is sufficient to produce a lowering of the freezing temperature of the solvent which is at least of the order of the temperature range impressed on the charge. While we discuss primarily molten zones in a solid matrix, the principles are applicable to solid or vaporous zones in a solid matrix, a requirement being that the diffusivity in the zone be substantially greater than in the matrix. Diffusion of solute into the surrounding solid will be assumed negligible. In general, its presence will not basically alter the conclusions to be drawn. For illustration, a system represented by the partial constitutional diagram of Fig. la will be discussed, in which k, the distribution coefficient defined in the figure, is constant and less than unity. However, the technique is applicable to any solute- solvent system in which one component lowers the melting point of another component. Movement of a Molten Zone in a Temperature Gradient Consider, in the system AB of Fig. 1, where B is designated the solute and A the solvent, the effect of sandwiching a thin layer of solid B between blocks of solid A and placing the whole in a temperature gradient such that the temperature of the layer is above the lowest melting temperature of the system. Surrounded by an excess of A, the layer will dissolve A, becoming molten, and expand in length." As so- lution of A continues, at both interfaces, the mean solute concentration in the zone will move to the right in Fig. la, until at temperature T, the liquid at the cooler interface reaches the liquidus concentration C,. Solution of A thereupon ceases because the liquid T1 is saturated with A. The liquid at the hotter end of the zone, being at temperature T2, is not saturated with A at concentration C1. Hence solution of A continues there and concentration C2 is approached. A concentration gradient therefore is set up in the zone, causing A to diffuse toward the cool end and B toward the hot end. As a result, the liquid at the cool interface becomes supersaturated and a layer of crystalline A containing concentration kc, of B in solid solution freezes. Since a source of A

Jan 1, 1956

By Bernard Greifer, Walter Rose

The purpose of this note is to call attention to a source of difficulty which can be responsible for inaccurate estimates of wetting liquid pressure gradients in mixture flow experiments of the Hassler1 type. It has been our experience occasionally to observe what were indicated to be negative pressure gradients, and these were regarded as anomalous in the sense that physically they seemed to contradict the requirement that the flux be in the direction of the potential field. At first it was thought that our scheme of assembling barriers and core sample led to such asymmetry in the distribution of isobars that the manometric leads at each end of the core were responding to internal pressures (within the core sample) which could be either positive or negative with respect to each other, and which in fact might tend to reflect on different effective core lengths in an unpredictable fashion as the wetting liquid saturation was changed. However, no compelling evidence of this possibility has been established. In addition, we were cognizant of the requirements to be satisfied in selecting manometric instrumentation to minimize the delay in response of the manometer to the differential pressures being measured, and were thus assured that our observations of anomalous pressure gradients could not be explained by faulty instrumentation. What we suggest is that if a leak sink occurs in the fluid lines connecting the core to either side of the differential manometer, errors exceeding 100 per cent may result in the estimation of wetting liquid pressure gradient, even though the leak is of such small magnitude that its existence would tend to be obscured by evaporation effects. This is because in a system with leaks at the specified places, the manometer rec- ords at steady state the pressure drop across the manometer barrier elements in addition to the pressure drop across the core sample. This possibility will be illustrated below analytically and by numerical example for the special case where the leak occurs on the high presure side of the core, since we are especially desirous to explain the significance of our observations of the so-called negative pressure gradients. It will be indicated, however, that leak sinks on the low pressure side of the core can account for observations of anomalously high values of pressure gradient, and that multiple leaks on both sides of the core can provide for some compensation so that the errors in pressure estimation are reduced. However, the major point to be emphasized is the fact that the impractical-ity of detecting the small leak sinks which give rise to the difficulties makes it a complicated task for the experimenter in a particular case to know with certainty that his estimation of pressure gradient lies within the limits of error which can be tolerated. Fig. 1 shows the electrical analog of the flow system we have employed in our studies. The inflow and outflow barriers. Rbl and Rb2, the manometer barriers, Rm1, and Rm2, and the core sample, Rc— for a particular fluid saturation and distribution— are all designated as resistance elements; the flowmeter is designated by an ammeter, A; the pressure source is designated by E; and the manometric device is designated by the voltmeter, V. Included in the circuit are the variable resistances, Rx and Ry, which may be regarded as the leak sinks, and which, in general, can vary in magnitude from zero (i.e., a large hole or shunt in the system) to infinity (i.e., no

Jan 1, 1950

By A. F. Buddington

INTRODUCTION EVER since a genetic connection between many ore deposits and magmas began to be widely recognized, some two-score years ago, there has been much discussion of the complex and intricate problem of the genetic association of specific kinds of mineralization with specific kinds of igneous rocks. General discussions of the latter problem and pertinent data have been given by S. F. Emmons, Kemp, Lindgren, Niggli, Rastall, Spurr, Vogt, and others. In this paper no attempt is made to deal with mineral deposits genetically associated with volcanic rocks, but only with those presumed to be related to exposed intrusive masses. The writer is indebted to E. S. Bastin, F. F. Grout, Edward Sampson, and to the members of the committee in charge of the preparation of the volume, for a critical reading of the manuscript and many worth-while suggestions.

Jan 1, 1933

By C. C. Singleterry, D. L. Katz

The critical phenomena have been studied during the past century but our knowledge of the critical temperatures and pressures of complex hydrocarbon mixtures still is very limited. The critical temperatures and pressures of pure substances have been examined in large numbers120 and in great detail.11.17 No experimental determinations of the critical phenomena have been reported on such complex hydrocarbon systems as a reservoir fluid. The critical temperature is defined by Taylor18 as follows: "there is some temperature for each gas above which the gas cannot be liquefied. This temperature is called the critical temperature." The critical pressure of a pure substance is the vapor pressure at the critical temperature. It should be noted that these definitions refer to a given substance in the pure state and do not mean that the pure substance cannot be liquefied in the presence of a second constituent. The normal procedure for obtaining the critical temperature of a substance is to heat it in a glass tube 1,20 under pressure until the meniscus between the liquid and vapor phase disappears, although other methods, especially for mixtures, have been used.13,14 However, when considering oil and gas reservoirs, it is more enlightening to consider a critical phenomenon that occurs when a mixture of oil and gas are compressed at a reservoir temperature until the meniscus disappears because the two phases become equal in composition. This conception, along with erroneous applications of the definition of the critical phenomena of a pure substance to that pure substance when it is part of a complex mixture, has caused confusion even among persons familiar with the classical theories. The purpose of this paper is to discuss the critical phenomena of pure substances and mixtures and to report experimental data on a mixture of

Jan 1, 1939

By C. C. Singleterry, D. L. Katz

The critical phenomena have been studied during the past century but our knowledge of the critical temperatures and pressures of complex hydrocarbon mixtures still is very limited. The critical temperatures and pressures of pure substances have been examined in large numbers120 and in great detail.11.17 No experimental determinations of the critical phenomena have been reported on such complex hydrocarbon systems as a reservoir fluid. The critical temperature is defined by Taylor18 as follows: "there is some temperature for each gas above which the gas cannot be liquefied. This temperature is called the critical temperature." The critical pressure of a pure substance is the vapor pressure at the critical temperature. It should be noted that these definitions refer to a given substance in the pure state and do not mean that the pure substance cannot be liquefied in the presence of a second constituent. The normal procedure for obtaining the critical temperature of a substance is to heat it in a glass tube 1,20 under pressure until the meniscus between the liquid and vapor phase disappears, although other methods, especially for mixtures, have been used.13,14 However, when considering oil and gas reservoirs, it is more enlightening to consider a critical phenomenon that occurs when a mixture of oil and gas are compressed at a reservoir temperature until the meniscus disappears because the two phases become equal in composition. This conception, along with erroneous applications of the definition of the critical phenomena of a pure substance to that pure substance when it is part of a complex mixture, has caused confusion even among persons familiar with the classical theories. The purpose of this paper is to discuss the critical phenomena of pure substances and mixtures and to report experimental data on a mixture of

Jan 1, 1939

By M. R. Hatfield, F. J. Vosburgh

In a recent article, it was shown that in the blast furnaces in Germany that are lined with carbon blocks no cooling plates are used, and that shower cooling is employed on the hearth and bosh sections. While one of the authors was in Germany he was told that one furnace was being operated without even the shower cooling on the bosh section, though the hearth section was shower-cooled. In discussion of this interesting situation with a number of blast-furnace operators in this country, it was made clearly and promptly evident that shower cooling was very unpopular, probably because of its messiness and its ineffectiveness. Both of the causes for the dislike of shower coolings are reasonable ones. Shower cooling can be and frequently is messy, but the present cooling of blast furnaces leaves much to be desired on that score. Shower cooling is ineffective as compared with plate cooling, so far as its usefulness in keeping the bricks cool enough not to melt or fall to pieces is concerned. However, the introduction of carbon linings changes the situation. No one is concerned with keeping a carbon lining cool, for no temperature in the blast furnace has any effect on carbon, which is just as stable at 3000°F. as it is at 70°F. The only concern is for the shell—to keep it cool enough for safety and comfort— and for that shower cooling is sufficient. Of course, with only the shell to cool, instead of the shell plus all the refractory material, much less water would be required, and the necessity for constant attention to the flow would be lessened, as the hundreds of inlets and outlets would be eliminated. Probably half of the water used in cooling a blast furnace is used for cooling the shaft and tuyeres and the remainder for the bosh and hearth sections. However, in view of the dislike of shower cooling in the United States, and particularly because at least one German blast furnace is operated with no cooling of the bosh section, thought was given to the possibility that a carbon-lined blast furnace might be operated without any cooling of the entire carbon-lined portion. For that reason a series of experiments was performed to determine what might be the temperature of the shell of a blast furnace protected by a carbon lining and operated under varying conditions up to a maximum inside temperature of 3000°F. Experimental Procedure A schematic diagram of the experimental setup is shown in Fig. I and a photograph of the entire assembly in Fig. 2. The heating element was a a tubc nominally 25/8 in. 0.d. by 2 in. i.d. by 30 in., used as a resistor. Power was furnished by a I5-kva. transformer operating

Jan 1, 1942

By M. R. Hatfield, F. J. Vosburgh

In a recent article, it was shown that in the blast furnaces in Germany that are lined with carbon blocks no cooling plates are used, and that shower cooling is employed on the hearth and bosh sections. While one of the authors was in Germany he was told that one furnace was being operated without even the shower cooling on the bosh section, though the hearth section was shower-cooled. In discussion of this interesting situation with a number of blast-furnace operators in this country, it was made clearly and promptly evident that shower cooling was very unpopular, probably because of its messiness and its ineffectiveness. Both of the causes for the dislike of shower coolings are reasonable ones. Shower cooling can be and frequently is messy, but the present cooling of blast furnaces leaves much to be desired on that score. Shower cooling is ineffective as compared with plate cooling, so far as its usefulness in keeping the bricks cool enough not to melt or fall to pieces is concerned. However, the introduction of carbon linings changes the situation. No one is concerned with keeping a carbon lining cool, for no temperature in the blast furnace has any effect on carbon, which is just as stable at 3000°F. as it is at 70°F. The only concern is for the shell—to keep it cool enough for safety and comfort— and for that shower cooling is sufficient. Of course, with only the shell to cool, instead of the shell plus all the refractory material, much less water would be required, and the necessity for constant attention to the flow would be lessened, as the hundreds of inlets and outlets would be eliminated. Probably half of the water used in cooling a blast furnace is used for cooling the shaft and tuyeres and the remainder for the bosh and hearth sections. However, in view of the dislike of shower cooling in the United States, and particularly because at least one German blast furnace is operated with no cooling of the bosh section, thought was given to the possibility that a carbon-lined blast furnace might be operated without any cooling of the entire carbon-lined portion. For that reason a series of experiments was performed to determine what might be the temperature of the shell of a blast furnace protected by a carbon lining and operated under varying conditions up to a maximum inside temperature of 3000°F. Experimental Procedure A schematic diagram of the experimental setup is shown in Fig. I and a photograph of the entire assembly in Fig. 2. The heating element was a a tubc nominally 25/8 in. 0.d. by 2 in. i.d. by 30 in., used as a resistor. Power was furnished by a I5-kva. transformer operating

Jan 1, 1942

By Howard C. Dunkle

Various factors can affect the quality of BIII2 and BIII3 steel as produced in a bessemer plant; among them: vessel-charging practice, blowing practice, ingot-pouring practice, ingot delivery-time practice, pit-heating practices, and ingot-rolling practice. Evaluation of the influence of ingot delivery time on quality has been chosen as the subject for this paper because this time is completely within the control of the operator, and on this particular factor there is a tremendous amount of information in the dusty archives of the average steel plant. In order to know how much improvement can be made and when attention should be directed to other factors that influence quality, in the continual struggle for improvement, the effect of ingot delivery time must be accurately evaluated. Once this is done, the importance of other variables can be accurately obtained, thus eliminating the necessity of resorting to opinions that are of doubtful value at best. In the study described herein, extensive use was made of the statistical card system as a method of determining the effect of ingot delivery time as a quality factor in bessemer screw-stock grades by simple direct correlation. The value of this statistical method as a means of accurately determining the influence of various factors has been amply demonstrated by Work1 for the bessemer process and by Hand and Gould2 and Fetters and Chipman3 for the open-hearth process. The quality records of 300,000 tons of bessemer screw-stock billets were used in this study of the effect of ingot delivery time on the rejections for breaks, pipe, check and seams. The reduction in the number of rejections for poor quality reduces the costs and increases the productivity per man-hour. The operator today, more than ever before, must know how to keep costs down, how to do it most quickly and in the best way, and how to obtain the highest quality in line with the ever increasing demands of the customer. It is necessary for him to know the individual relations and interrelations between various factors affecting the quality of the manufactured product if he is to produce material that will meet competitively the cost, performance, and quality demands of the trade. Significance of Steel Manganese, Mixer Silicon and Steel Sulphur as Quality Factors In order to obtain the highest grade of material it is necessary to control many factors—not just one or two, as operators

Jan 1, 1945

By John A. Garcia

A standard set of coal mining laws for the entire United States is hardly practicsble, yet the numerous variations in the state laws for almost every item seems entirely unnecessary. The same useless variations appear in almost every comparable section with no apparent reason except that no attempt has ever been made to codify them, and as they were developed over a long period of time by innumerable individuals and legislatures, the present situation is the logical outcome of lack of cooperation between states. The ventilation of a mine is affected indirectly by many provisions not listed specifically under this heading, so that it would be necessary to tabulate the major portion of all the laws to secure a complete comparable digest; therefore only a few of the more important have been set down here. This point is well illustrated in the section providing for clearance between car and rib, which is intended as a safety measure against personal injury, but is very important from the standpoint of ventilation because of choked airways in mines on two-entry system. Confusing Phraseology Misinterpretation and confusion may be expected from the phraseology alone; one state provides that the scale of the mine map shall be "not more than 100 ft. to 1 in.;&apos;&apos; another state demands "not less than 100 ft. to 1 in." Both probably mean the same thing and seek to prevent the operator from furnishing a map on which the workings will appear SO small that the detail is illegible. Legislation is certainly indefinite that specifies structures must be fireproof when "near" a mine opening, and just what is a "dusty" or "gaseous" mine is open to argument in most of the states. The variation in spacing crosscuts and break-throughs and the limited number of men on a split seem entirely unnecessary, as the distance is not reduced in gaseous fields, excepting in Arkansas and Tennessee, which states produce a comparatively small amount of coal, and the number of men differs 100 per cent. and more for no apparent reason.

Jan 1, 1927

By R. W. Balluffi, R. Resnick

NUMEROUS investigations of chemical diffusion in a brass have been made and the results are collected in several places.1-3 This work has been mainly concerned with the determination of the chemical diffusivity as a function of composition and temperature. In 1947 Smigelskas and Kirken-dall&apos; showed that zinc and copper diffuse at different rates in face-centered-cubic brass, and since then, a number of efforts have been made to determine the intrinsic diffusivities of zinc and copper in this alloy.1, 5-9 Horne and Mehl8 in particular have recently determined the intrinsic diffusivities as functions of temperature and composition using sandwich-type couples and inert markers. Inman et al." also have determined the intrinsic diffusivities in homogeneous alloys using tracer techniques. When the present work was started, no information of this type was available. Consequently, measurements of the intrinsic diffusivities were made as a function of temperature at a constant composition of 28 atomic pct Zn with vapor-solid diffusion couples where the zinc was diffused into the diffusion couple from the vapor phase. The application of these couples to the study of diffusion in a: brass has been described previously.0,7 The temperature dependence of the intrinsic diffusivities was found to follow the relation D, = A, exp(-Hi/RT) and the values of Hzn, and Hcu, were found to be closely the same. It is emphasized, however, that the chemical dif-fusivity (D = N1D2 + N2D1) is a composite diffusivity and does not necessarily follow this exponential form. It is usually found to do so within experimental error for substitutional alloys because the heats of activation of the intrinsic diffusivities generally are not greatly different.&apos;" Also, at the onset of this work, there was no information available concerning possible unequal diffusion rates of individual components and the existence of a Kirkendall effect in alloys with other than face-centered-cubic structures. Since then, two reports indicating a Kirkendall effect in body-centered-cubic ß brass have appeared. Landergren and Mehl" have published a note describing Kirkendall diffusion experiments with sandwich-type couples. Inman et a1.9 also find a Kirkendall effect in this alloy using the tracer technique. In the present work, several aspects of the Kirkendall effect in ß brass were further investigated using vapor-solid couples. Two different couples were used, one in which the zinc was diffused into the specimen from the vapor phase and the other in which the zinc was diffused out of the specimen into the vapor phase. Briefly, the existence of a Kirkendall effect is confirmed and it is found that Dzn/Dcu = 3 at about the 46 atomic pct composition in this alloy at 600°, 700°, and 800°C. As a result of the unequal diffusion rates of zinc and copper, volume changes occur and subgrain formation is observed in the diffusion zone. In addition, significant porosity is produced by the precipitation of supersaturated vacancies. Diffusion in this alloy is therefore outwardly similar to diffusion in a brass where these effects are also observed, a Brass Experimental Methods—The use of vapor-solid couples in studying diffusion in a brass has been described in previous articles.6,7 The method briefly consists of sealing a copper specimen with Kirkendall markers initially placed on its surface in an evacuated quartz capsule along with a large zinc source of fine a brass chips and then diffusing the zinc into the specimen through the vapor phase. The zinc concentration at the specimen surface rises rapidly enough to a value near that of the a brass source so that the surface concentration may be regarded as constant during diffusion. Under these boundary conditions, values of the chemical diffu-sivity may be obtained by applying the Boltzmann-Matano analysis to the concentration penetration curve, and the intrinsic diffusivities may be obtained from Darken&apos;s5 equations when the velocity of marker movement is known. The diffusion specimens were made from OFHC copper in the form of disks 3.2 cm diam and 0.5 cm thick with faces surface-ground parallel to within +0.001 cm. Markers in the form of fine alumina particles <0.0002 cm diam were placed on the specimen surface. These specimens were then sealed in quartz capsules along with enough a brass chips of a 30.0 atomic pct Zn composition to keep the source concentration from decreasing by more than 0.3 atomic pct Zn as a result of the loss of zinc to the specimen during diffusion. The quartz capsules which were initially evacuated to a pressure of

Jan 1, 1956

By M. R. Tek

A new method for correlating the data on multiphase flow through vertical pipe is presented. The correlation is based on a "two-phase f factor" concept which was developed and successfully applied to horizontal multiphase flow by Bertuzzi, Tek and Poettmann. Field data previously published on several flowing and gas-lift wells have been used as the basis for the developed correlation. The application of the method to actual two-phase flow problems indicate that this method is capable of predicting the pressure distribution in vertical multiphase flow strings well within the accuracy range usually desired for common engineering and design calculations. A new working chart developed for calculation of two-phase pressure gradients and a graphical step-by-step procedure for the computation of pressure distribution are presented along with an example problem. INTRODUCTION Multiphase flow through vertical pipe is encountered in many engineering installations. In petroleum, chemical process, nuclear engineering and many other industries, problems associated with simultaneous flow of two or more phases through vertical pipe have been of interest for a long time. This interest has increased considerably during recent years due to applications to new processes in petroleum production and refining and to problems of steam generation and heat removal from nuclear reactors. One prominent example of vertical two-phase flow is provided by the gas-lift process where oil, water and gas flow simultaneously. If the pressure profile in a gas-lift well can be predicted within reasonable accuracy, it would be possible to get good estimates of the power required to lift the oil, the optimum depth, the pressure and the rate at which to inject gas. Furthermore, the effect of production rate and tubing sizes on these quantities can be evaluated before any design decision is made on the installation and operation of the flow string. The majority of experimental work available in the literature deals with two-component systems where individual phase flow rates in and out of the pipe remain constant. The general problem of prediction of pressure drops in multiphase flow systems is very complicated. The co-existence of numerous flow patterns of widely different geometry and mechanism, conditions of surface instability and the nature of force fields acting upon the system are among the major difficulties commonly encountered. The classical approach of fluid dynamics which would be based upon the formulation and solution of Navier-Stokes equations has been found by many investigators completely devoid of any hope of success-—not only because of inherent nonlinearities but also because of insurmountable analytical difficulties standirng in the way of setting up the boundary conditions. The presence and effect of interfacial forces on mu1tiphase flow systems further complicate the theoretical approach. For these reasons, many investigators choose to adopt semi-empirical if not purely empirical approaches in order to obtain solutions of engineering utility. A prominent practical solution has been given by Poettmann and Carpenter&apos; in the form of an empirical correlation. In their paper, total flowing densities of fluids and solubility effects of gas in oil have been taken into account for the correlation of field data covering a wide range of operating conditions for oil wells. They treated the gas. oil and water as a single phase of combined propcrties and correlated the multiphase friction factor as a function of the product (pvd), i.e., density X velocity X diameter of the flow string. However, because the product (pvd) is dimensional while the frictior factor is dimensionless, the generality of their result&apos;s is somewhat restricted. It seems that the omission 01 viscosity effect may be one of the reasons for the scatter of data as shown in their correlation chart. The concepts of the "two-phase f factor" and the "two-phase Reynolds&apos; number function" were recently developed and successfully applied to correlate horizontal multphase flow by Bertuzzi, Tek and Poettmann.&apos; Recently, two new methods of correlation by Tek and Chan&apos; have been presented on simultaneous flow of liquid and gas through vertical pipe. These two methods of correlation and the working equations in field units necessary for their application are included in this paper. The extension of the conccpt of two-phasc Reynolds&apos; number function successfully developed for horizontal flow into vertical multiphase flow systems, development and evaluation of working charts permitting calculation of two-phase pressure gradients and

By Daniel Hanson

FoR most of their practical applications metals are required to withstand stresses of appreciable magnitude: indeed, it id because they possess the quality of resisting stress without becoming permanently deformed that they find such extensive use in the service of man. Metals and alloys must, in service, usually behave as elastic substances—or nearly so. It is not difficult to satisfy this condition at ordinary temperatures. Iron and its alloys, especially the steels, are at normal temperatures excellent elastic bodies, capable of satisfying most of the mechanical requirements of the engineer: where electrical, chemical or other properties are impor-tant, which cannot be met by steels, it is usually possible to find a non-ferrous alloy such as nickel, copper or aluminum, which will prove satisfactory. When the metals or alloys are not inherently sufficiently elastic, cold-working or heat-treatment may develop elastic properties to a sufficient extent for practical needs. By means of relatively simple, rapid tests we can measure such properties as elastic modulus, limit of proportionality and proof stress, upon which design can be based with confidence. The case of the soft metals, such as lead and tin, is well known to be exceptional. They possess no definite limit of elasticity, and the value of proof stress or tensile strength depends to a great extent on the speed with which the test is carried out. Design here must be based on other considerations than a well-established theory of the proportionality of stress and strain. It is now generally recognized that steels and non-ferrous alloys possess at temperatures not greatly exceeding that of the atmosphere, characteristics quite different from those existing at ordinary temperatures, and that they assume qualities similar to those of the soft metals. Not only have they no limit of elasticity, but the proof stress and the ultimate stress depend on the time of application of the load. Flow under load may persist for long periods of time, possibly indefinitely, and the determination of a true maximum stress becomes a matter of great difficulty.

Jan 1, 1939

By Daniel Hanson

FoR most of their practical applications metals are required to withstand stresses of appreciable magnitude: indeed, it id because they possess the quality of resisting stress without becoming permanently deformed that they find such extensive use in the service of man. Metals and alloys must, in service, usually behave as elastic substances—or nearly so. It is not difficult to satisfy this condition at ordinary temperatures. Iron and its alloys, especially the steels, are at normal temperatures excellent elastic bodies, capable of satisfying most of the mechanical requirements of the engineer: where electrical, chemical or other properties are impor-tant, which cannot be met by steels, it is usually possible to find a non-ferrous alloy such as nickel, copper or aluminum, which will prove satisfactory. When the metals or alloys are not inherently sufficiently elastic, cold-working or heat-treatment may develop elastic properties to a sufficient extent for practical needs. By means of relatively simple, rapid tests we can measure such properties as elastic modulus, limit of proportionality and proof stress, upon which design can be based with confidence. The case of the soft metals, such as lead and tin, is well known to be exceptional. They possess no definite limit of elasticity, and the value of proof stress or tensile strength depends to a great extent on the speed with which the test is carried out. Design here must be based on other considerations than a well-established theory of the proportionality of stress and strain. It is now generally recognized that steels and non-ferrous alloys possess at temperatures not greatly exceeding that of the atmosphere, characteristics quite different from those existing at ordinary temperatures, and that they assume qualities similar to those of the soft metals. Not only have they no limit of elasticity, but the proof stress and the ultimate stress depend on the time of application of the load. Flow under load may persist for long periods of time, possibly indefinitely, and the determination of a true maximum stress becomes a matter of great difficulty.

Jan 1, 1939

By E. H. Jr. Dix

OF all the alloying elements used in commercial aluminum alloys, copper stands out as by far the most important, and it is perhaps for this reason that the constitution of the aluminum-copper system has received the attention of a number of experimenters covering a period of approximately 20 years. It would be expected that during this time the equilibrium relations had been thoroughly and exactly worked out. In a general way this is true, but there is a surprising lack of agreement in the details of the high aluminum end of the diagram, particularly in regard to the solid solubility of copper in aluminum, which has been given variously as 2 per cent. to 5 per cent. at the eutectic temperature. The importance of this is much greater than might at first appear to one unfamiliar with modern commercial aluminum alloys. This is true because, with one exception, the susceptibility of the strong alloys to heat treatment depends, in part at least, upon the solid solubility relations of copper in aluminum. In 1919, Merica, Waltenberg, and Freeman1 published the first detailed information on these solubility relations. They found that the solubility of copper decreases with falling temperature from about 4 per cent. at 5.25° C. to about 1 per cent. at 300° C. and is apparently still diminishing at lower temperatures. In 1921 there was published a brief account of the results obtained in the National Physical Laboratory, Teddington, England.2 This laboratory, however, reported that 5 per cent. of copper is soluble in aluminum at 540° C., and that this amount decreases to about 3 per cent. at 20° C.

Jan 2, 1926

By E. V. Potter, E. T. Hayes, H. C. Lukens

LARGE volumes of hydrogen are liberated at the cathode during electrolytic precipitation of manganese. Most of the gas escapes from the electrolyte, but a considerable amount may be entrapped in the manganese plate. Gas has been observed to escape from manganese melts in puffs that ignite at the surface. It has been reported that castings made with electrolytic manganese tend to rise in the molds; for this reason the manganese is often treated to remove hydrogen before the melt is made or it is premelted and used as cast manganese in making the alloys. The effect of hydrogen on the properties of manganese and its alloys is not known, but its effect on iron and iron alloys has been studied extensively.1.2 The close relationship between iron and man¬ganese suggests that hydrogen may have a similar effect on the properties of manganese and its alloys. The purpose of this investigation was to determine the amount of hydrogen or other gases in typical commercial electrolytic manganese sheet and to investigate ways of removing it most conveniently. APPARATUS The apparatus used is shown schematically in Fig. I. It consists of a chamber A in which the metal sample is placed, a vacuum or pressure gauge B, volume gauge C, vacuum pump D, hydrogen container E, auxiliary gas chamber F, and furnace G. The specimen chamber was made of two concentric quartz tubes. The outer one, a, connects with the closed gas system and is surrounded by the furnace G. A second tube, b, fits closely inside a and has a small end that projects into the space for the specimen and holds the thermocouple for measuring the temperature of the sample. The inner tube is joined to the outer tube outside the furnace, with rubber tape and sealing wax, to prevent gas leakage into or out of the closed system. This type of specimen container is loaded very easily and can be used several times if molten metal does not come in contact with the quartz. An ordinary mercury manometer B is used to measure the pressure in the system. The volume gauge C is essentially another mercury manometer, but the volume of the column is much larger than normal and the height of the mercury can be varied by raising or lowering the well H. In this apparatus the tube had a volume of I00 c.c. for a 60-cm. length. For larger changes in gas volumes; auxiliary containers F were used to increase the volume of the system by known amounts. Valves were arranged so that these auxiliary containers could be filled from the system and evacuated by the pump as often as necessary to accommodate the increases in the volume of gas in the system. The furnace G, used to heat the samples, was equipped with an automatic temperature controller, which maintained the desired temperatures within ± 5°C.

Jan 1, 1945

By AIME AIME

THE following Officers, Directors, and guests were present: Herbert Hoover, A. R. Ledoux, Henry S. Drinker, Edwin Ludlow, Samuel A. Taylor, Charles F: Rand, William M. Corse, Arthur S.. Dwight, Glen H. Clevenger, L. W. Francis, F. G. Cottrell, Bradley Stoughton, Percy E. Barbour, E. P. Mathewson, Dorsey A. Lyon, Archibald Douglas, A. D. Flinn, RobertLinton, James F. Kemp, William Y. Westervelt, J. W. Richards, W. L. Saunders, George Otis Smith, Thomas T. Read, J..C. Murray, Ralph Arnold. A Committee on Mine Equipment was appointed composed as follows: Graham Bright, chairman, William Kelly, Howard N. Eavenson, R. E. Hobart, and S. P. Rumsey. B. D. Saklatwalla was added to the Committee on Miscellaneous Metals and W. Spencer Hutchinson was added to the Committee on Mining Geology. A revised budget for 1921 was approved. A petition duly signed to amend Section 1., of Article III of the Constitution, increasing the initiation fees from ten dollars to twenty dollars, was approved by the Board.

Jan 1, 1920