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By Julian M. Avery

In its dual role of pig-iron smelter and gas producer, the blast furnace is a remarkably satisfactory and efficient apparatus. Many metallurgists and engineers have pointed out, however, that since the primary function of the blast furnace is to produce pig iron at the lowest possible cost, its function as a gas producer should be subordinated to this primary purpose. During the past 10 years or more, improvements in blast-furnace technique and economy have, in fact, been directed primarily to increasing efficiency in the use of the reducing power of the gases produced by combustion of coke at the tuyeres, to reduce iron ore within the furnace. The net over-all result is a decrease in the fuel value of the top gas per unit of volume, and per ton of pig iron, which is evidently more than offset in value by the corollary saving in coke and the possibility of increased furnace capacity, for otherwise there would be no point in making such improvements. The purpose of the present paper is to suggest that, while progress has been made in this direction, there is another approach to the problem of increasing the chemical and thermal efficiency of the blast furnace in its primary role as a pig-iron smelter, which appears to offer possibilities of improvement in over-all ecorlomy of a different order of magnitude than results thus far obtained by the use of other expedients. The present argument is based in large part upon the hypothesis that the efficiency and economics of pig-iron smelting are seriously and adversely affected by the phenomenon known as "solution loss," and that the problem of solution loss call be successfully attacked by increasing the over-all pressure; i.e., the "top prcssure" under which the furnace is operated. It is indicated that pressure operation may also be expected to result in concomitant benefits, which may be summed up as generally improved operating conditions, together with a substantial saving in fuel and/or a substantial increase in furnace capacity. In a broad sense, the suggestion of pressure operation of the pig-iron blast furnace is not new, for operation under moderately increased over-all pressure was suggested as early as 1871, by no less an authority than

Jan 1, 1938

By W. F. Boericke

INTRODUCTION THE Wisconsin zinc district, or the Upper Mississippi lead. and zinc district as it is also termed, lies in the southwestern corner of Wisconsin, and embraces adjacent portions of Illinois and Iowa. It includes Iowa, Grant, and Lafayette counties in Wisconsin, and Jo Davies county in Illinois. In Iowa, Dubuque formerly produced considerable lead, but there has been little mining there in recent years. The map, Fig. 1, shows the entire district, with roads, railways, streams, and the various towns, or "camps," around Which the mines. are clustered. The hatchwork indicates the areas iii which lead and zinc have been mined. The district is about 60 mi. (96 km.) north and south and about 40 mi. (64 km.) east and west. Not all of the territory is mineral bearing, and there are considerable areas that are believed to be barren. The grouping of the mines is patchy and irregular, though certain broad zones of mineralization extend almost the full width of the district, as from Mineral Point west through Mifflin and Livingston, and from Shullsburg west through New Diggings and Hazel Green. It is worth noting that the best mines of the district have, to date, been found within 10 mi. east or west of the fourth principal meridian line, thus lying within a long, narrow, north-and-south belt extending the length of the district. In a field as large as the Wisconsin, which has only within com-paratively recent time been worked intensively for zinc, the. chances are good for, opening new and important orebodies in parts of the district not yet, or insufficiently, prospected. However, the prospecting has been most successful around, or adjacent to, the old lead diggings of nearly a century ago, and the camps that were well known then are still centers of activity. In their order of importance they are: New Diggings, Benton, Mifflin-Livingston, Galena, Linden, Hazel Green, Shullsburg, and Highland.

Jan 8, 1919

By H. H. Power, C. H. Pishny

When an oil operator becomes a party to a proration agreement he may wonder, with good cause, whether production prorated .today is merely deferred until tomorrow or whether oil might be lost. Various types of evidence obtained from production records when studied quantitatively are of great assistance in arriving at definite conclusions. A study of individual examples cited in this paper leads towards some solution of the problem, particularly when they are considered in the aggregate. Many production curves on various pay horizons were studied. A disappointingly large number of these were of contributory value, but inconclusive. However, there were enough curves of similar type from the Wilcox sand at Earlsboro, Bowlegs, Seminole City, the Cromwell horizon at Little River, and the Simpson dolomite at Valley Center, Kansas, from which reasonably definite conclusions were drawn. Assuming that deferred production is later made up with no increase in ultimate recovery, a curve (Fig. 1) shows the normal flowing and pumping life of a composite well, contructed by the family curve method. The initial production of the well shown is 1700 bbl. daily and the allowed production is 25 per cent. On this basis the average daily allowed rate for the first month is 425 bb1., or the area BCDE, which is equivalent to the area AFDG under the normal decline curve. The potential production for the second month is 1500 bbl. and the allowed production 375 bbl. daily. By this procedure a potential curve for each succeeding month is obtained (points A, H, I, J and K). If the well is opened it should produce somewhere near its potential curve for a short period and then decline at a more rapid rate than the potential curve. This theoretical analysis is basic. Actual examples exhibiting all points raised by the ideal curve are rare. Proration in the Mid-Continent area has been effected mostly by leases rather than by individual wells; hence a well may produce any

Jan 1, 1931

By W. E. Brigham, P. W. Reed, J. N. Dew

By John J. Gilman

BECAUSE of their layerlike structure, zinc crystals exhibit strong anisotropies for almost all physical and chemical properties. This should, and indeed does, greatly influence the plasticity of zinc for various crystal orientations. At low temperatures, the investigator of this plastic anisotropy is plagued by the great variety of deformation modes that operate. However, at high temperatures (250° to 419°C) only two deformation modes predominate: basal (0001) and prismatic (1010) glide. Furthermore, since strain hardening is virtually absent at high temperatures, the plasticity for these two modes of deformation can be very simply described by means of two equations of state. It is the purpose of this paper to describe the experimental behavior of basal and prismatic glide in zinc crystals, and to interpret this behavior in terms of other physical properties (in particular, the thermal expansion coefficients and the elastic constants) using the theory of dislocations. Fig. 1 defines the two planes of the zinc structure that will be discussed. Glide occurs very readily on the basal planes at all temperatures, and there is a very large literature on this subject. Much of the literature has been reviewed by Schmid and Boas;' it will not be reviewed here. Kolesnikovl was the first to show that if basal glide is circumvented by stressing a zinc crystal parallel to the basal planes (giving zero shear-stress on the basal planes) then, at temperatures above about 320°C, glide on the first-order prism planes occurs. His results have recently been confirmed by Cahn, Bear, and Bell." These previous workers have established the existence and crystallographic elements of prismatic glide; the present paper is concerned with the stress, strain rate, and temperature relations of prismatic glide as contrasted with basal glide. Experimental Methods The crystals were square ones, 6x6 mm, that had been grown in precision Pyrex tubes by a method that is described in detail elsewhere.' Most of the crystals were 99.999+ pct Zn (New Jersey Zinc Co. CP grade). Some were alloyed with 0.1 -+-0.005 atomic pct Cd, and chemical analysis showed that almost all of the added cadmium persisted through the crystal-growing process. For measurements of nonbasal glide, crystals were oriented with their basal planes parallel to both the rod axis and one of the flat faces of the square cross section. However, the orientation of the close-packed directions [1210] with respect to the rod-axis was variable. For basal glide measurements, the angle between the basal plane and the specimen axis was 35". The orientations were measured by the Gren-inger back-reflection X-ray method. The problem of finding a suitable method of gripping the crystals was the most serious experimental obstacle that arose. Because of the large plastic anisotropy of zinc, the usual gripping methods were unsatisfactory. Some methods that were tried were: high melting-point solder, making heads on the ends by locally melting a crystal, and electroplating nickel on the ends to form enlarged portions. For all these methods, the regions of the grips were weaker than the crystals themselves. Finally, two methods were decided upon: bend tests and direct machining of tensile specimens. In the bend tests, specimens were loaded as simple beams so that gripping was not a problem. The beams were 1 in. long and the axis of bending was parallel to the hexagonal axis of the crystals. For the crystals that were machined into tensile specimens, brass bars with slots in them were used to support the crystals, and thereby minimize the distortions due to machining. The crystals were glued into the brass bars with plastic cement which was later dissolved away with acetone. See Fig. 2, left. No clamps were used near the crystals and the machining was done using a milling machine with a fly-cutter. The tool bit was very sharply pointed to minimize burnishing. The feed was less than 1 mil per cut. The depth of cut was 2 mil for roughing cuts, and % mil for the finishing cuts. This machining method produced surface layers of tiny recrys-tallized grains only 2 to 3 mil deep, and the bodies of the crystals were not measurably disturbed. After the crystals had been machined and removed from the brass holders, they were chemically polished until about 5 mil had been removed from all their surfaces. The polishing reagent consisted of equal parts of concentrated HNO,, 30 pct H3O and ethyl alcohol; it is described in detail elsewhere." A typical crystal is shown in Fig. 2, right. The I-shaped faces are normal to the hexagonal axis of the crystal; otherwise the projections at the ends would simply shear off when the crystal was loaded. The cross section in the 2?-in. gage length is 0.215x0.115 in. It was found that the polished

Jan 1, 1957

By R. A. Burmeister, P. E. Greene

Two methods for the synthesis and growth of single crystals of B6 P are described: a solution-growth process employing nickel as the solvent, and a vapor-growth process employing BBr3 and pH3 as the reac-tants. Relevant portions of the Ni-B-P phase diagram have been examined and liquidus data are presented for an isobaric section at an equivalent P2 pressure of 3.8 Torr, and an isothertnal section at 1300°C. Solution-growth techniques are described and the purity and crystalline perfection of the resulting material is discussed. Epitaxial growth of BeP on &P substrates has been obtained using the vapor-phase system. Evidence is presented which supports the assignment of the stoichioknetry B6P to boron sub-plwsphide. THE B-P system differs from other III-V systems in that it contains two distinct compounds. The existence of the monophosphide (BP) has been known for some time,' whereas the subphosphide (B6P) was reported only recently.' Both of these compounds are large bandgap semiconductors (Eg = 2.0 ev for BP~ and 3.3 ev for B6P4), and are therefore of interest for optoelectronic applications. The crystal structure of B6P is quite different from those of most semiconductors, being derived from that of a-rhombohedral boron by the incorporation of the two phosphorus atoms in the intericosahedral sites of the a-boron unit cell?76 B6P also exhibits a number of unusual characteristics, including a high degree of chemical inertness, hardness, and high-temperature stability. No information concerning other physical properties is available in the literature. The present study is part of a broader investigation of the preparation and properties of B6P. This paper considers methods of growing single crystals of B6P of suitable size and quality for physical-property measurements. A detailed discussion of the electrical and optical properties of B6P will be given elsewhere.' GENERAL CONSIDERATIONS The method first used to synthesize B6P was the disproportionation of BP' according to the reaction The equilibrium P2 pressures corresponding to this reaction were also determined .'" It is therefore possible, in principle, to apply several of the reactions reported for the synthesis of BP to the synthesis of B6P merely by selecting lower phosphorus pressures or higher temperatures, in accordance with the equilibrium data. Other techniques for the direct synthesis of microcry stalline B8P have also been reported.1°

Jan 1, 1968

By W. P. Haynes

No wildcat operations are recorded from France during the past year, and no new discoveries have been made. In northern Africa, in Morocco, some prospecting continued in the Gharb and Tselfat regions. Only very small production or shows were found. At the close of the year one cable-tool well (depth 400 meters) was drilling in the Tselfat district, and one rotary well in the Gharb. In Tunisia one well was drilling at Sloughia. Refinery building has been active under the new petroleum law, no less than six plants now being under construction. At Pechelbronn, it is estimated 130 wells were drilled, of which 73 wells, or 56 per cent, were productive. Total drilling was 45,000 m. One new Jurassic horizon was discovered. In the mining area approximately 17,500 m. of new gallery were driven. Production at Pechelbronn for the first nine months was as follows: From wells, 233,013 bbl.; from mines, 164,815 bb1.—a total estimated production for the year of 532,000 bbl. Production at Gabian was 3780 bbl. for the year. In Algeria production from Tliouanet was small, being estimated at 6510 bbl. This production is from Helvetian sands (Miocene) around a salt plug. Italy Production for the year was 211,500 bbl., an increase of 62 per cent over that of last year. Drilling to the extent of 97,000 ft. was done mainly by the A. G. I. P., the government company in the Province of Emilia. More locations are being tested in this area, where geophysical results have shown indications of buried uplifts. Oil has been encountered on two of these structures, at Fontevivo and Podenzano, but the wells have given trouble with salt water. The chief producer is the Societa Petrolifera Italiana at Salsomaggiore and Valezza. The production is from sand lenses at relatively shallow depths. New concessions of 2000 hectares were granted at several points in the Po Valley, and geophysical work is being carried on. The A. G. I. P. is working on a five-year program of exploration to test new areas.

Jan 1, 1933

By William G. [Peryam], Bishop Ottey M., Fred E. Johnson

THE Lepanto Consolidated Mining Company is the largest copper producer in the Philippines, and the only one that makes a concentrate valuable principally for its copper; also, it has the only productive copper mine situated at considerable distance from the sea, and is the only one in the islands operating its own smelter. The Lepanto mine is in the Municipal District of Mankayan, sub-province of Benguet, near the heart of the Mountain Province of Northern Luzon. It is 165 km. from its shipping point at San Fernando, Province of La Union, on the shore of the China Sea. Elevations at the property range from 3200 to 4500 ft. The climate is very mild; temperatures are seldom below 50° or above 80°F. Annual rainfall approaches 170 in. and is mainly confined to a rainy season lasting from May to October. The months from December to April, inclusive, are usually extremely dry. This climatic pecularity entails the problems of landslides on the roads during the rainy season and water shortage during the dry season. The Mountain Trail, an improved rock-surfaced toll road maintained by the Commonwealth Government, gives access to the property. The 105 km. over this road may be traveled in about 4 ½ hr. during the dry season. Very few sections of the road are straight for more than 100 meters, and about one third of it is a one-way road controlled by gates. All freight for the property is delivered by the Manila Railroad Company to Bauang, La Union, 45 km. west of Baguio and at sea level, where it is picked up by freight trucks and hauled via Baguio to Lepanto. Granulated matte is hauled in bulk from Lepanto in four-ton lots on freight trucks to the storage bins at San Fernando. Freight rates from Bauang to the property amount to P8.00 per ton, and from the property to San Fernando the rate is P16.00 per ton. The company pays the road toll, P1.00 per truck, each way. THE CAMP The company maintains a modern camp, well separated from the mine and reduction plant. Comfortable and sanitary living quarters, water, and light, as well as free medical service are provided all employees. A hospital staffed by a doctor and two nurses takes care of all medical treatment. Considering recreational facilities of great importance, the company has provided two tennis courts, two basketball courts, and badminton courts for employees. Bowling alleys and a motion picture theater are operated by the company, the profits being expended for other recreational purposes. A moderate sized recreation hall serves for barrio dances, meetings,

Jan 1, 1942

By A. F. Giamei, E. J. Freise

A discussion of the various factors affecting the accuracy of volume fraction determination by the direct comparison X-ray diffraction method is presented. To minimize errors introduced by nonrandomization effects such as preferred orientation and large grain size, as well as errors introduced by statistical effects, an iterative mathematical analysis is introduced. This analysis is applied to all observable diffractio~ spectra from a given specimen by means of computer techniques and is statistically superior to the standard direct comparison technique which utilizes only one or tm sets of intensity spectra. The computer program also presents a graphical interpretation of- the results which enables the investigator to visualize and readily assess the scatter in volume fraction estimates caused by deviations from randomness. Finally, the iterative analysis is applied to experimental data collected from a series of plain carbon steels in both the as-received and spheroidized conditions to determine the volume fraction of cemen-tite present in each case. The results show markedly good agreement with chemical analyses for all spheroidized specimens. In theory, quantitative X-ray diffraction is a power-ful analytical technique for precise determination of the volume fractions of various phases present in a multiphase poly crystalline aggregate. There are two generally used methods; both utilize the fact that the intensity of a diffraction line of a particular phase is a function of volume fraction of that phase present in the aggregate. The more common method is the so-called internal standard technique where a known amount of standard substance is mixed with the aggregate containing the unknown. The resulting ratio of the intensity of a particular diffraction line of the unknown to the intensity of a diffraction line from the standard is used to find the weight fraction of unknown material by reference to the intensity data obtained from a previously prepared set of standards containing the same amount of standard material. The details of this technique are outlined in standard works on X-ray diffraction.' The disadvantages of the technique are that it requires the use of powder specimens and that the powder mixture must be homogeneous near the surface to the maximum effective beam depth. The alternative technique is the direct comparison method in which the ratio of the intensity of a diffraction line of a phase in the aggregate to the intensity of a second-phase diffraction line yields the ratio of the volume fractions of each phase present. This method has been applied most extensively to the determination of the percentage of retained austenite in martensitic steels and to determining the amounts of hcp and fcc allotropic modifications in pure cobalt5 and the amounts of hexagonal and rhombohedra1 modifications in graphite.8 This method is applicable to bulk as well as powder aggregates and is the technique which will be considered in the following text. It is the purpose of the present communication to show that by combining the results of X-ray diffrac-tometry with the use of high-speed digital computers the results of the direct comparison quantitative X-ray analysis technique can be optimized by using all of the data available on a diffraction pattern. THEORETICAL DISCUSSION In optimizing any quantitative X-ray diffraction experiment, the problem of accuracy vs time to collect and analyze the experimental data arises. For any method to be practical, it is required that both experimental and analytical procedures are reasonably short. In most of the previous work performed by the direct comparison method, intensity data from only one or two sets of peaks were used to calculate the volume fraction of phases present in the aggregate. Consequently, rather long-time experimental measurements are required to assure that the intensity data are sufficiently accurate to justify the use of one or two sets of data. By using computer techniques to analyze the experimental data it becomes feasible to use all of the available data on a diffraction pattern. By so doing, the time spent in measuring any one diffraction maxima can be appreciably reduced. Although this results in poor counting statistics for any one maxima, the number of data points available for analysis is greatly increased. Based on the above discussion, it will be assumed that a continuous scanning counter-diffractometer technique will be used to collect intensity data from a two-phase mixture. The integrated intensity of the ith diffraction line from the a phase in the aggregate is given by:'" where is the volume fraction of the a phase, The various quantities in Eq. [la] are angular independent while those in [lb] depend on the hkl spectrum of a particular phase. The meaning of the individual quantities in Eqs. [la] and [lb] are given in Appendix 1. It is convenient at this point to outline briefly the factors which will affect the measured intensity of any one hkl spectrum. a) Extinction effects arise from two independent experimental conditions. Primary extinction arises from a high degree of crystal perfection and results in spectra having lower intensity than predicted by Eq. [I]. Any treatment, such as powdering, which reduces

Jan 1, 1968

By J. L. Lamon, W. Crafts

P. Coheur and L. Habraken—We read this paper with great interest and are glad to congratulate the authors for their valuable work, supplying an important contribution to the mechanism of tempering on the carbides in vanadium steels. We are in a good position to appreciate this work since we have been studying, for more than a year, Cr-Mo steels of a composition similar, but less highly alloyed (namely 0.1 pct C, 3 pct Cr, 1 pct Mo). Our results are quite in concordance with the authors', however, we wish to point out that it is very interesting to use equally the electron microscope in order to observe the variations of microstructure in steels. We have studied simultaneouslv the evolution of the carbides in situ with the electron microscope, and, after extraction, again with the electron microscope, and then with X-rays. The first results which we have obtained have been communicated at the Congress of Delft (July 1949) and at the "Journbes de la Metallurgie" in Paris (October 1949). These may be summarized as follows: After tempering with varying either the tempering temperatures or the tempering times, the carbides show two evolutions. The first one is connected to the carbides existing in the steels, principally in the boundaries of the grains. For some groups of steels these carbides may coalesce and for other groups they may

Jan 1, 1951

Since the comprehensive review of the Persian fields presented by Sir John Cadman last year, operations have proceeded normally. No developments of especial importance fall to be recorded and it remains only to bring up to date the full information given at the beginning of 1933. Controlled production from the Masjid-i-Sulaiman and Haft Kel fields has been maintained at slightly higher rates than during 1932. The figures for the past five years are as follows: These represent crude oil and products piped to the coast but exclude products reinjected into the reservoir, a process that has been in continuous operation at Masjid-i-Sulaiman during the period under review. The systematic delimitation of the Haft Kel field has been continued during the past year and results have been sufficiently encouraging to justify the inception of a wider scheme for distribution of production. Drilling has been resumed recently in the Persian sector of the Naft Khaneh field, and preliminary survey work is in progress for the selection of a site for a refinery at Kermanshah arid the construction of a connecting pipe line. Investigations in connection with the scientific control of reservoir were dealt with in considerable detail in last year's review. This work has been steadily pursued during 1933 and certain of the investigations have been the subject of papers presented to the World Petroleum Congress held in London in July of last year.

Jan 1, 1934

By F. H. Gilpin

SINCE Noah pitched his ark within and without with pitch, the use of asphalt in human endeavor has been increasing-for Noah's pitch was asphalt. Asphalt is a bituminous material found in nature, either pure or admixed with smaller or greater quanti-ties of mineral and non-mineral materials, or obtained by the refining of crude asphaltic-base petroleum under proper methods of control. Native or "natural" asphalts are scattered through-out the world, though the commercial value of the various deposits varies greatly, depending upon both their accessibility and magnitude and the quality of the material found. It is an acknowledged fact that such asphalts have been produced through natural causes by practically the same application of tempera-ture and pressure as are used in the modern refining of crude asphaltic-base petroleum. The best known of all the native asphalt deposits are those of Trinidad Lake in the Island of Trinidad, British West Indies, and of Bermudez Lake in Vene-zuela. Asphalt from Trinidad Lake, after refining to remove organic and some inorganic diluents, contains approximately 35 per cent, of inorganic residue, and the asphalt thus produced must be fluxed with lighter asphaltic or semi-asphaltic base oil to make it com-mercially utilizable. The refined asphalt obtained from the Bermudez Lake deposit contains from 4 to 6 per cent. of inorganic material which cannot be removed. This asphalt, also, must be fluxed to produce com-mercial products. Small quantities of similar materials are available in other locations. The best pure native asphalt' is known as. gilsonite and is mined in com-mercial quantities in the State of Utah. In numerous places in the United States, particularly Oklahoma and Kentucky, there are deposits of sand¬stone and limestone impregnated with bitumen, which are known as rock asphalts. These rock asphalts may be used, particularly in the paving industry, either as found or by slight fluxing; from some deposits the asphalt is extracted and marketed commercially.

Jan 2, 1923

By AIME AIME

STRIP coal mining in the United States has-become noted for its massive equipment, especially its power shovels. Notable among the latest examples of this trend is the Bobolink mine of the Binkley Mining Co., at Seeleyville, Ind.,. eight miles from Terre Haute. This is only one of the Binkley company's operating properties; in all, the company owns or controls 26 mines, in fourteen seams. The Bobolink, however, is the largest strip mine in America and probably also in the world. It has an estimated life of fifteen years. The shovel used to strip the over¬burden is electrically operated, of Bucyrus-Erie make, and was. shipped to the property for assembling, a job

Jan 1, 1936

By R. W. Smith, K. H. Lee

Bond type simulated closed-circuit grindability tests and batch grindability tests were run on six pure minerals plus a limestone and a taconite ore. The simulated closed-circuit tests were made at five different meshes of grind. The minerals tested varied widely in hardness and breakage pattern. For all simulated closed-circuit tests both Bond and Holmes work indices were calculated and compared. The Bond grindability testlm6 has been widely and quite successfully used for predictions of such items as ball mill power requirements and as an aid in plant comminution equipment selection. The test is interesting in that although run as a series of batch tests it is over-all a simulated closed-circuit test with a circulating load of 250%. The simulated closed-circuit feature is probably the primary reason for the notable success of the test. Perhaps the major criticism that can be brought against the test is that it is time consuming, since it normally takes a trained technician about an eight-hour shift to perform it.4 For many purposes this is an acceptable time requirement. However, if a grindability test is to be used for mill control purposes it should be performed in as short a time interval as possible, preferably under an hour. Sometimes in industry strictly batch tumbling mill tests are run and an attempt is made to correlate such batch tests with plant mill operation. Then an attempt is made to adjust operating tumbling mills based on data from the tests. The tests, however, frequently do not correlate well with operating data. The purpose of the present work was to explore some of the similarities and differences between a simulated closed-circui.t grindability test and a batch type test. Six different minerals plus a limestone and a taconite ore were tested in the experimentation. These materials varied widely in hardness, breakage characteristics, etc. Standard dry Bond grindability tests were mn on all materials at 48, 65, 100, 150 and 200 meshes of grind. Feed material was prepared by stage cmshing to -6 mesh. Initial feed volume was 700 cc. Care was taken to maintain the standard constant weight (about 20125 gm) and number of balls (283) during all the tests. Rotational speed was 70 rpm. Table I lists the materials studied along with pertinent data regarding the materials and Bond grindabilities obtained. In addition, dry batch tests were performed on all materials. These tests were made in the same mill as was used for the Bond tests. An identical ball charge and an identical feed volume were used. After rotating the mill for a predetermined number of revolutions at the same rotational speed as for the Bond test, the material was removed and separated from the ball charge. A screen analysis was performed on this product. Knowing the original size distribution of the feed and the size distribution of the product, it was possible to calculate the grindability or grams of a particular mesh produced per revolution of the mill. After the screen analysis of the product, the various fractions were recombined and placed back in the mill for further grinding. After grinding for additional revolutions of the mill the procedure was repeated. Thus, it was possible to obtain grindabilities for each material at a number of meshes of grind and for various revolutions of the mill. Grind-abilities obtained from batch tests are shown in Table 11. COMPARISON OF BOND AND BATCH GRINDABILITIES Figs. 1A through 1D show relationships between batch and Bond grindabilities. Figs. lA, lB, 1C and 1D show respectively graphs indicating the relationships for batch tests run for 100, 300, 500 and 700 revolutions of the mill. For a particular material on each graph, points are shown for 200, 150, 100, 65, and 48 meshes of grind except for several missing coarse meshes of grind for galena which did not fall conveniently on the figures. For each material and graph the point nearest the origin is for 200 mesh, the next for 150 mesh, the next for 100 mesh, etc. Considering Fig. lA, it is interesting to note that all relationships shown are essentially straight lines. There are, however, considerable differences

Jan 1, 1969

By R. L., Fullman

During the past year there have been a number of significant investigations that have furnished evidence on the driving forces governing grain growth and on the role played by boundary impurities. Thus Burke has shown that in high purity alpha brass the rate of grain growth in the earliest stages is approximately inversely proportional to the existing grain size. This relation agrees with one derived by Zener assuming that surface energy was the driving force in grain growth. Also in confirmation of the surface energy hypothesis, Burke found that growth virtually stopped when the grain boundaries or even only the grain corners were melted.

Jan 1, 1949

By George Straghan, Ralph Thomas

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By Ralph Thomas, George Straghan

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By M. H. Pilkuhn, H. Rupprecht

The junction luminescence of GaAsxP1-x diodes containing up to 47 pct Gap was studied. Diodes were prepared by diffusing zinc into n-type material which was eithw boat- or vapor-gvown. Observations concerning the energy and the line shape of the spontaneous emission are presented and discussed; in particular the influence of inhomogeneous phosphorus distribution is considered. The role of reabsorption of the junction radiation is pointed out. With increasing current, the peak emission shifts to higher enwgy. This is alm true in cases where slow line narrowing occurs simultaneously. The length dependence of the threshold current density for lasing at 77 °K was examined for lasers made from the same material. It was found that longer lasers have lower threshold curvent densities, Estimates of the characteristic laser losses are given. Data concwning the range of Gap concentration in which stimulated emission was observed are presented. FORWARD-BIASED p-n junctions in mixed alloys of GaAsxPl-, emit light whose wave length depenfs on the composition of the alloy ranging from 8400A (x = 1) to 5350A (x = 0) at 77°K. Laser action in vapor-grown material was first reported by Holonyak and evacqua,' and in boat-grown material by Ainslie, Pilkuhn, and Rupprecht.' In both cases this was observed for low Gap concentration where GaAs,Pl-, is still a "direct" semiconductor with the lowest conductance-band minimum at k = 0 and a subsidiary minimum in the [loo] direction. As the Gap concentration is increased, the subsidiary [loo] minimum in the conduction band is lowered and finally becomes the lowest minimum for Gap concentrations above 50 pt,3 making the alloy an ''indirect" semiconductor. It is of interest to determine up to which Gap concentration stimulated emission can be observed. EXPERIMENTAL Boat-grown material was prepared by N. Ainslie of IBM by horizontal Bridgman technique. The material was n type and silicon-doped up to a concentration of 10'' cm-'. Vapor-grown material was made by E. Hull of IBM or received from Merck & Co. Diodes were fabricated in a similar manner as in the case of GaAs by zinc diffusion. Details about the diffusion can be found in a later paper.4 All diodes were of Fabry-Perot structure with two parallel sides cleaved and the other two sides sawed. Their width ranged from 50 to 150 p and their length from 50 to 700 p. RESULTS AND DISCUSSION Spectral Distributions. A typical display of the junction luminescence of a GaAsxPl-, diode is shown in Fig. 1. The liquid-nitrogen and room-temperature curves which were taken at a very low current (25 ma dc) show a relatively sharp high-energy emission which is band-edge radiation. They also show a broad low-energy emission which is due to transitions to deep impurity levels. This latter emission line may have different shapes and positions depending on the nature of the material. It can sometimes be quite near the band gap giving rise to "bumps" in the high-energy line. The results presented in this paper will be concerned only with the high-energy emission which becomes more intense relative to the low-energy emission when the current is increased and the temperature is lowered.

Jan 1, 1964

By G. H. BUCHANAN

ALTHOUGH the nomenclature of the chemical tools of flotation is probably familiar to you, it will do no harm to review it; . In order to make the terms more real I have employed an illustration which likens flotation to an old-fashioned balloon ascension, such as we witnessed in boyhood at the county fair. The mineral to be floated is the aeronaut, conspicuous in his gilt-spangled tights, who is to be separated from you and me and the other small boys who are standing about, said boys being the g-a-n-g-u-e, or g-a-n-g, as we would have spelled it. The oil film surrounding the bubble is the counterpart of the silken fabric of the balloon, and bubble and balloon will rise for. the same reason, namely. that the fluid outside it is heavier than the fluid within. In flotation reagent nomenclature the material of which the bubble is made is called the "frother.",

Jan 1, 1930

By J. H. Swisher

ALUMINUM deoxidation equilibrium in liquid iron has been the subject of many investigations. Sawamura and Sano1 have written a critical survey of the literature on this subject and consider the data of Gokcen and chipman2 and of d'Entremont, Guernsey, and Chip-man3 to be most reliable. The present study was undertaken to check these data and extend the range of the experiments to lower temperature. The experiments consisted of equilibrating 5-lb Fe-Al melts with recrystallized alumina crucibles at 1580o + 10oC, and analyzing the solidified ingots for aluminum and oxygen. The electrolytic iron stock contained 100 ppm C, 20 ppm 0, and trace amounts of other elements.* The stock was induction-melted in an atmosphere of 5 pet H2 in argon to attain equilibrium between the melt and the crucible. The temperature was measured with a W, 3 pet Re/W, 26 pet Re thermocouple, and the equilibration time was about 4 hr. The results are plotted in Fig. 1 along with curves obtained from the data of d'Entremont et al.,3 for temperatures of 1740o and 1910°C. The present results can be seen to be consistent with the previously reported high-temperature data. The reaction under study is AI2O3 (s) = 2 Al (l) +3O [1] for which the deoxidation product is Kl =[% Al]2 [%O]3 [2] (Under the experimental conditions, Fe A12O4 is not expected to form.4) In Fig. 2, values of log Ki evaluated at 0.01 pet A1 are plotted against 1/T, using data obtained from all the investigations under consideration. The deoxidation product is plotted in Fig. 2 in lieu of the equilibrium constant (normally obtained by evaluating Ki as pet A1 — 0) because of the uncertainty involved in extrapolating to zero concentration. The difficulty in extrapolating the present data for 1580°C is apparent curvature in the log Ki vs pet Al plot. This curvature is perhaps due to the uncertainty in oxygen analysis for concentrations of 5 ppm and below. For the data of Gokeen and chipman,' the extrapolation is also difficult because of experimental scatter. The line drawn through the points plotted in Fig. 2 may be represented by the equation:

Jan 1, 1968