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By J. G. Thompson

OXYGEN, nitrogen and hydrogen are present in practically all metals in one or more of the following forms: (1) molecular gas in blowholes or blisters, (2) combined in nonmetallic inclusions such as nitrides, oxides or silicates, and (3) in solid solution in the metal. Gaseous elements, in some of these forms, are encountered in practically all metals and alloys but possibly have received most publicity in connection with iron and steel. In fact, the entire steel industry depends upon the control of the oxygen content during the refining process, as well as in the finished material, and it was only after the adoption of the use of efficient deoxidizers such as manganese that the production of good steel with a low carbon content became possible. In normally clean, sound steel the amount of hydrogen is negligible and the amounts of oxygen and nitrogen vary from a few thousandths to a few hundredths per cent. However, many of the effects attributed(27,31,40.41,53,54,55,56,62) ? to the presence of these elements are important and at first glance appear to be out of proportion to the amounts of impurities involved. The presence of oxygen is believed to affect the solubility of carbon in austenite and ferrite and thereby to affect the structure of the iron or steel. Such properties as strength, hardness, ductility, elastic limit, impact resistance, magnetic permeability, tendency toward caustic embrittlement, irregularity in carburization, the cutting life of tools, certain corrosion phenomena, the presence of flakes, seams, bands, ghost lines and hair cracks, and the tendency to age-harden, all have been attributed to the presence of oxygen.

Jan 1, 1932

The first discovery of gold in Montana is credited to François Finlay, a half-breed, from the Red River country, in Canada; he went to California during the early days and learned there how to wash the gold from placer deposits; then, on his return, he crossed Montana and found gold on the western slope of the Rocky Mountains, on Gold creek, a minor tributary of the Hell Gate river, in what is now Deer Lodge county. That was in 1852.* Finlay did not find enough gold to induce him to continue at work, but six years later a group of miners, led by the brothers James Stuart and Granville Stuart prospected on this same creek, obtaining about ten cents to the pan. They, however, were harassed by the Blackfeet Indians, and they were also handicapped by lack of proper tools; so they too desisted from further operations. Two years later, in 1860, Henry Thomas started to work on Gold creek with three sluice-boxes hewn out of green timber that he cut on the spot. With this simple apparatus he won from $1.50 to $2.00 per day. This may be considered the fist instance of systematic mining in Montana. Meanwhile the Stuarts went to Fort Bridger, in southwestern Wyoming, where they remained as traders until 1861, when, again lured by the gleam of gold, they returned to the valley of the Deer Lodge and resumed prospecting, using 10 sluice-boxes that were brought from Walla Walla, in Washington, 425 miles distant. In the summer of 1862 they were joined by many others, chiefly from Colorado, in consequence of an exchange of

Jan 1, 1932

By G. A. Vissac

The only fine coal washer with proved automatic controls, the feldspar jig is capable of good efficiencies even at low separating gravities, handles a variety of products, and treats 150 tph and over. IN continental Europe the feldspar jig is used almost exclusively for cleaning the fine sizes of coal; it operates with an artificial bed, made up generally of pieces of feldspar or of any other hard and heavy rock with good cleavages. A primitive form of this machine requiring close supervision was used in this country years ago, but output was small. The modern machines are generally air-pulsated Baum-type jigs, with capacities up to 150 tph, and treat sizes from % in. to 0, usually previously dedusted or deslimed. These jigs are equipped with very accurate and sensitive automatic controls insuring satisfactory operation even at low separating gravity and with feeds irregular in quality and quantity. This paper will deal more particularly with coal cleaning separation, but the technical studies apply equally to all minerals. Theory of the Feldspar Jig To understand fully the operation of the feldspar jig and to appreciate its potential value, it is necessary to measure and analyze the motion of small particles of various specific gravities, falling in various media, under various conditions. As no practical formulas were available for that purpose, the writer has developed new theories and established new sets of formulas, which cannot be demonstrated here. They are applicable to all minerals and to many problems of coal or mineral concentration. These formulas do not pretend to absolute accuracy, but results, tested by comparison with experimentally recorded data, are sufficient for practical purposes, as they give definite indications of trends, relative values, and order of magnitude of the many factors involved. For pulsating motions no earlier formulas are available. In the case of continuous currents or motions, such formulas as Rittinger's, Allen's, or Stokes', over a hundred years old, apply only to special shapes and sizes of particles, involve factors and coefficients difficult to measure or appreciate, and deal only with free motions. They are of little use in solving practical problems. Units used with the formulas presented here are in the CGS system. Lateral friction and suction have been taken into account according- to methods currently used in aerodynamics, and only hindered motion is dealt with. As the feldspar jig is primarily intended to create a fluid bed condition, the mixture of fluids and solids obtained is homogeneous, and the apparent specific gravity of the separating medium is calculated accordingly. For instance, if 20 pct of the volume is coal and shale, with an average of 1.60 sp gr, in a liquid of 1.10 sp gr, the actual specific gravity of the separating fluid is 0.80 x 1.1 + 0.20 X 1.6 = 1.20. The fundamental equations are as follows: The general motion of a particle falling in a medium of specific gravity equal to u, hindered motion. is dv/dt = g/Ls [ L (s-u) - u/g v2 [1] g = 981 cm per sec, acceleration of gravity, and L = thickness of the particle of specific gravity (s) and velocity (v). The initial acceleration dv/dt = g (1-u/s ) [2] is a function of the specific gravity of the particle, only for a given medium, and independent of its dimensions—an ideal separating condition. The terminal velocity Vt = gxL- (s-u)/u, [3] for a given value of u, is a function of s and L. Two particles, L, s, and L2 s2, are said to be equivalent if they have the same terminal velocity, and accordingly L1/L2=s2-u/s1-u. [4] Two such particles cannot be separated by continuous currents, in any concentrating device. Because the initial accelerated motion, which provides for efficient separation, is followed by a constant velocity, which has a limiting effect, it is essen-

Jan 1, 1956

By AIME AIME

THE Chairman of the Iron and Steel Division for 1945 is one of the most versatile and best-known men in this industry, with wide experience in research and operations and in handling both the men and the materials that are used in enormous quantities. Erle G. (Doe) Hill was born in Santa Ana, (alit, April 21, 1890 and graduated (Bachelor of Science) in mining and metallurgy from the University of California in 1913. For the next five years lie held a variety of jobs as miner, foreman, and null superintendent in gold, silver, copper, and quicksilver mines in the West and in Mexico. As Doe was an individual endowed with an exceptional amount of horse sense, he left the West in 1918, to become instructor of mining engineering and ore dressing at Carnegie Institute of Technology, and while in that post did considerable consulting work as a geologist and mining engineer. In 1920, still possessing the same common sense. he got out of mining engineering and geology and became associate professor of metallurgy at the University of Pittsburgh, a position he retained for nearly ten years.

Jan 1, 1945

By Everett H. Graff, Ray H. Misener

THE Sol de Oro mine is in the province of Nazca, 487 km. southeast of Lima, and 60 km. inland from the coast at an elevation of 1200 m. above sea level. From Lima the mine may be reached in 8 hr. by automobile; 472 km. from Lima to Nazca over the paved Pan-American Highway and 15 km. from Nazca to the mine over a good graveled road. The trip from Lima can also be made in 2 hr. via the Faucett Air Lines which make two stops weekly at Nazca. The [Compania] Aurifera Nazca, owning and operating the Sol de Oro mine, was organized in Lima in 1930 by a group of prominent Peruvian mining men, including Ing. Carlos Alvarez Calderon, Dr. Alfredo Alvarez Calderón, Ing. Hector Boza, Ing. Jorge Félix Remy, Ing. Eulogio Femandini, Sr. Fernando Wiese, and Sr. Julio East. The nine claims in the Sol de Oro group owned by the company comprise an area of 52 square kilometers. Development of the property was not started until 1932 and only then under adverse conditions, owing to lack of transportation facilities. Mining machinery and other supplies could be taken as far as Ica by boat and railroad, but to transport them over the 180 km. of hot, sandy desert from Ica to the mine was a problem. There was no road in those days and only a few of the most venturesome truck drivers cared to contract the hauling. Another problem the company had to face was that of securing adequate labor. The Sol de Oro is in an agricultural region, and was forced to look to the near-by cotton plantations for men. Experienced men were imported from the "sierras," but they did not stay. The men are accustomed to high altitudes and cold climate and cannot easily acclimate themselves to the hot and arid coastal region. As a consequence the company has been forced to hire the inexperienced local laborers and train them for mining. The company has established three separate camps at the Sol de Oro property. Each is approximately one kilometer from the other and connected by auto road. The upper mine camp consists of living quarters for 300 workmen and their families, a general mine office, carpenter shop and timber-framing shed, compressor house, drill-sharpening and drill-repair shop, first-aid station, time office, school and store. At the central or "empleados" camp there is a 200-ton cyanide plant, general offices, warehouse, powerhouse, shops, laboratory, hospital, school, guest house, an 18-room hotel for the single staffmen, and 12 completely modern five-room cottages for the married staff employees. At the lower camp are living quarters for 200 workmen and their families, two general stores, a school and a small theater. Below this camp, along the river, are the company wells and pumping plant supplying water for mine, mill, and camp uses.

Jan 1, 1945

By H. C. Vacher

THE limiting concentrations of carbon and oxygen which may co-exist at equilibrium in liquid iron are important in determining the degree to which liquid steel may be refined before it is deoxidized. Most refining processes depend upon the oxidation of a highly carburized iron which invariably results in contaminating the steel with oxygen. The oxygen .thus introduced presents many problems to the refiner, who in turn has attempted to rid the steel of this impurity by deoxidation with elements such as manganese, silicon and aluminum. The importance of the limiting concentrations of carbon and oxygen is accentuated in view of a number of recent researches which have indicated in many instances the existence of relations between oxide inclusions and dissolved oxygen and physical properties and chemical behavior of steel. The determination of the equilibrium concentrations of carbon and oxygen existing in iron under steelmaking conditions is obviously of fundamental importance. It has been generally assumed that the product of the equilibrium concentrations of carbon and oxygen in liquid iron is a constant and that this product is directly proportional to the carbon monoxide pressure in equilibrium with the liquid iron. Herty1,2 has computed values for this product based on open-hearth data which are all in the neighborhood of 0.01 to 0.03 (per cent. FeO X per cent. C) for temperatures in the vicinity of 1550° to 1600 C. and one atmosphere pressure. Kinzel and Egan3 have attempted to determine the value of this product by exposing liquid iron to carbon monoxide at one atmosphere pressure. The value reported by them was 0.0005 at 1550°. C. In. order to apply certain equations to the rate of carbon elimination in the open-hearth process, Feild4 found it necessary to assume. a value of 0.0102 at 1580° C. for this

Jan 1, 1931

By Frank H. Riddle, Wilfrid R. Foster

GENERAL treatment of the various minerals of importance in refractories appears in the chapter entitled "Refractories" elsewhere in this volume. The present chapter is restricted to a discussion of minerals of the sillimanite group and brings up to date the excellent information contributed by Prof. Paul F. Kerr to the first edition (1937). Since the appearance of that edition, the status of the group has changed some- what. Kyanite remains the preferred source material for mullite refractories but total consumption of kyanite has increased considerably.85 The exigencies of World War II forced an increased dependence on domestic sources and led to an intensification of the search for higher-grade deposits of kyanite and allied minerals. The first discovery of massive kyanite similar to that of India has been reported from Georgia.37 British East Africa has joined India as a substantial supplier of our imported kyanite, but that from India continues to hold preference.85 During World War II, prices of both domestic and foreign grades reached peaks unparalleled since the earliest years of the use of kyanite and as yet have shown no tendency to return to prewar levels. Topaz, by virtue of the deposit outlined in South Carolina, merits inclusion in the group.20,36,95 Large andalusite deposits, which threaten to rival our one large domestic occurrence, have been found in Russia.69,88 Sillimanite has not yet attained an important position among these useful minerals because of the lack of accessible deposits of high-quality material in adequate supply.37,50,58 Tests by the Bureau of Mines have indicated the possibilities of economically beneficiating low-grade sillimanite and kyanite.105.106,140 Government, university, and industrial

Jan 1, 1949

By William B. Harris, Leonard Greenburg, Gustav Werner

Haulage in tunneling operations generally has been done with electric locomotives. As a rule, on short hauls the source of electricity is a storage battery mounted on the locomotive, which, of course, must be removed and recharged periodically. Where the distance from the recharging point to the tunnel face is very long, and where loads are heavy, trolley-driven locomotives are used. Diesel engines have been used in mining and tunneling operations in Europe for a number of years. The recent reports of studies in Belgium1 and by the Bureau of Mines in this country2-4 have indicated the potentialities of this form of power for haulage, mucking, bulldozing and many other underground operations. The hazards attending the use of Diesel engines in more or less closed spaces have long been known. The exhaust constituents that may create a harmful or objectionable environment are carbon monoxide, oxides of nitrogen and sulphur, carbon dioxide, aldehydes and smoke. Lack of precise information regarding the concentration of these gases and the ventilation requirements to reduce them to safe levels has to some extent suppressed their general acceptance in tunneling and mining work. Not until the work of the Bureau of Mines referred to above, and certain experience gained in the construction of the Delaware Aqueduct, ‡ has there been available the requisite information regarding the conditions under which their use may be permitted. This paper concerns itself with the successful operation of Diesel engines underground in the construction of certain parts of the Delaware Aqueduct, and describes the conditions under which Diesel engines have been found to operate with a minimum production of noxious gases. The test data reported were obtained during the operation of Diesel engines over a period of two years.* Studies by the New York State Department or Labor Exhaustive tests were made by the Division of Industrial Hygiene, of the composition of the exhaust gases given off by a Diesel engine mounted on a test block. These tests showed that certain' quantities of the gases are discharged from the exhaust. On the basis of these figures, preliminary requirements of design and control

Jan 1, 1943

By Gustav Werner, Leonard Greenburg, William B. Harris

Haulage in tunneling operations generally has been done with electric locomotives. As a rule, on short hauls the source of electricity is a storage battery mounted on the locomotive, which, of course, must be removed and recharged periodically. Where the distance from the recharging point to the tunnel face is very long, and where loads are heavy, trolley-driven locomotives are used. Diesel engines have been used in mining and tunneling operations in Europe for a number of years. The recent reports of studies in Belgium1 and by the Bureau of Mines in this country2-4 have indicated the potentialities of this form of power for haulage, mucking, bulldozing and many other underground operations. The hazards attending the use of Diesel engines in more or less closed spaces have long been known. The exhaust constituents that may create a harmful or objectionable environment are carbon monoxide, oxides of nitrogen and sulphur, carbon dioxide, aldehydes and smoke. Lack of precise information regarding the concentration of these gases and the ventilation requirements to reduce them to safe levels has to some extent suppressed their general acceptance in tunneling and mining work. Not until the work of the Bureau of Mines referred to above, and certain experience gained in the construction of the Delaware Aqueduct, ‡ has there been available the requisite information regarding the conditions under which their use may be permitted. This paper concerns itself with the successful operation of Diesel engines underground in the construction of certain parts of the Delaware Aqueduct, and describes the conditions under which Diesel engines have been found to operate with a minimum production of noxious gases. The test data reported were obtained during the operation of Diesel engines over a period of two years.* Studies by the New York State Department or Labor Exhaustive tests were made by the Division of Industrial Hygiene, of the composition of the exhaust gases given off by a Diesel engine mounted on a test block. These tests showed that certain' quantities of the gases are discharged from the exhaust. On the basis of these figures, preliminary requirements of design and control

Jan 1, 1943

Jan 1, 1932

By H. K. Work

THE instrument for the rapid determination of carbon in steel, described in this paper, was developed originally to facilitate the opera-tion of the pilot-sized open-hearth furnace in the Jones & Laughlin Research and Development Laboratory. In this small furnace, with its shallow bath, the drop in carbon is accelerated, and a rapid, reliable test for carbon content is indispensable. This problem becomes rather acute when it is desired to finish heats at a carbon content higher than can be estimated with any degree of accuracy by the fracture test. Several independent methods for determining carbon were investigated, therefore, and it was found that a relatively simple magnetic device could be made to give reproducible results. A laboratory instrument was designed and set up for the use of the furnace operators. It was tested exhaustively in the laboratory and was used with considerable success for following the carbon content in the furnace bath. As soon as suffi-cient data had been compiled to indicate that the instrument might have a wider application, a more rugged model was constructed and placed in the mill to be tested on commercial heats. Finally, about a year ago, instruments were furnished to the plant open-hearth shops, and these have been in use since that time. As a matter of convenience, the instrument has been named the "Carbanalyzer," and will be referred to by this designation in the following pages. ?

Jan 1, 1939

Jan 1, 1967

By M. J. Sinnott, W. R. Kiessel

The creep characteristics of commercially pure titanium sheet in the annealed state, cold-worked state, and cold-worked and recovered state in the temperature range from 75' to 750°F have been determined. Titanium has been found to exhibit strain aging characteristics. The effect of strain aging on creep has been determined. A possible explanation for the poor creep properties of titanium is proposed. THE metal titanium exhibits many desirable properties but results on its creep properties have been somewhat disappointing. The creep strength is low even though the material has a very high melting point.' The present work was undertaken to determine the creep strength of titanium in various conditions; annealed, cold-worked, and cold-worked and recovered and to determine why titanium shows such relatively poor creep properties. The general procedure followed in this research consisted in obtaining the usual mechanical prop- erties such as creep strength, short time tensile strengths, and hardness on materials treated to a controlled degree of internal strain, as determined by X-ray diffraction measurements, and their subsequent interpretation in terms of this internal strain. The material used in this work was sheet stock taken from one heat of commercially pure titanium. As-received, this sheet was 0.060 in. thick. The analysis was given as 0.037 pet C, 0.023 pet Si, 0.50 pct W, 0.063 pct Ni, 0.08 pct Fe, and the remainder titanium. The oxygen and nitrogen were unreported but generally are about 0.2 pct in commercial heats. In order to put the material in a state of minimum internal strain all the sheet was given an anneal in a static argon atmosphere for 1 hr at 1600°F prior to processing and testing. The microstructure of the material after this treatment was essentially a single-phase solid solution of uniform equiaxed grains. For the studies on the cold-worked sheet, the material was reduced by rolling in a two high, 5 in. mill. Rolling was done at room temperature in passes

Jan 1, 1954

By Paul-Emile Mercier

LOADING efficiency depends on cycle capacity of the loader, conditions of the mine, and mine organization. Cost of operation is the final criterion. Two types of loaders are analyzed-the boom shovel and the tractor-excavator. Studies were made in an open pit at Kimberley, Nev., where shovels are the production units and the tractor- excavator is a clean-up loader. The report deals mainly with the analysis of cycle and output. Problems of pit organization are not acute. (Other studies included in the original report and omitted here covered tractor-excavator application underground.)

Jan 4, 1957

By J. S. Ross

Although the opinion has prevailed for several years that bottoni-hole choking under certain flow conditions should effect an increase in flow efficiencies, the use of bottom-hole chokes until recently has been limited in application mainly because of mechanical difficulties encountered in their construction. Within the past year, however, bottom-hole choking, through the development of a removable type of choke, has been applied successfully under various conditions of flow in many Mid-Continent fields. The observation of these field tests indicates that bottom-hole choking, although not applicable to all flow conditions, has an important place in the operation of oil and gas wells. This paper gives briefly the conclusions drawn from the data obtained from the experiments with this bottom-hole choke under various flow conditions, and a description of the choke and its operation. Purpose of Bottom-hole Choking Since, in a normal well, the velocity with which the column of gas is moving generally has a direct bearing upon the quantity of oil it can lift, probably the main purpose of bottom-hole choking is to accomplish an increase in the velocity of this- rising column, particularly in the lower portion of the tubing string. This it does first, by expansion of the free gas accompanying the oil; next, by liberation and expansion of some of the occluded gas normally carried in the oil to the surface; and lastly, by atomization, which results in a more intimate and uniform mixture of the oil and gas. It is apparent, then, that if this velocity, particularly in the lower portion of the flow string, at a given rate of production, is inefficiently low, owing either to an insufficient supply of gas or to excessive surface choking, and slippage takes place, bottom-hole choking should bring about an increased velocity of the gas and hence an increased lifting capacity. But if the velocity of the column of gas at this same rate of production through a surface choke alone is at or above a velocity necessary to lift the oil efficiently, increasing the velocity by bottom-hole choking would probably serve no useful purpose, other than to steady the flow by the better mixture of oil and gas and to lower delivery pressures.

Jan 1, 1932

By T. A. Read, S. W. Kitchen, H. I. Fusfeld

At the present time most artillery cartridge cases are used only a single time. Since the process of reshaping a fired cartridge case so that it may be used again is much simpler and cheaper than the original manufacture of the case, it is clear that important savings could be effected if such re-formed cases were used in place of new cases. Extensive use of reconditioned cases has been hindered in the past, however, by the deterioration of the brass which may occur in the period of time between the first firing and the reconditioning of the cartridge cases. This deterioration sometimes results in a dangerously high incidence of firing splits in groups of reconditioned cartridge cases. It appears that the mechanism of the deterioration is the season cracking of the brass, for season cracks, of varying degrees of severity, may frequently be found in the cartridge cases after their return from the field. There are, of course, severe practical limitations to the extent to which fired cartridge cases can be protected from corrosion under battle conditions, particularly since the powder residue in the case is itself corrosive. The present paper describes a rapid method of testing the sidewalls of artillery cartridge cases for the presence of season cracks. This method has been developed specifically for use in connection with the reconditioning of fired cases, and makes it possible to carry out 100 per cent inspection. This new method of inspecting cartridge

Jan 1, 1945

By Albert B. Horn, J. J. McKetta, O. L. Culberson

Since water is present in natural gas and petroleum reservoirs, it is of engineering value to have accurate experimental data regarding the behavior of water in hydro-carbon systems. Since experimental data of this nature are so scarce in literature, a program is under way at the University of Texas to obtain experimental data regarding the distribution of water in petroleum hydrocarbons. This initial paper is subdivided into three parts: A. The apparatus and analytical procedure are discussed. B. The equipment has been checked by comparing the experimental data with data of literature on the solubility of methane in water at 77°F and pressures to 10,000 psia. C. Experimental data are presented at 100, 160, 220, 280, and 340°F on the solubility of ethane in water at pressures to 1200 psia. As the temperature is increased the solubility of ethane in water first exhibits a minimum and then a maximum solubility. The range of applicability of Henry's Law is discussed. INTRODUCTION Although considerable experimental data have been published on water-hydrocarbon systems in the hydrate region, the information on these systems in the vapor-liquid and the vapor-liquid- 'References are given at end of paper. Manuscript received at the office of the Petroleum Branch August 31. 1949. liquid regions at elevated pressures is extremely scarce. A survey of the literature on hydrocarbon-water systems at elevated pressures was presented by McKetta and Katz12,13,14 showing the systems and phases investigated. In addition to these existing published data, Poettman and Dean" have reported the water content of propane in the three-phase region (only the propane-rich liquid and the vapor phases were studied) and Michels, et al.15 have reported the solubility of methane in water at pressures to 6800 pounds per square inch at 77°F and at pressures to 1500 psia at temperatures to 300°F. It has been shown12,14 that the presence of water will materially affect the phase equilibrium of hydrocarbon systems. In order to make experimental studies on the quantitative effect of the presence of water in naturally-occurring hydrocarbon systems, it is desirable to have data available on binary hydrocarbon-water systems. A program is underway at this laboratory to determine the phase relations of the hydrocarbon-water systems. Initially the investigation will be limited to binary systems with water as one of the components. Later ternary and complex systems will be investigated and reported. EQUIPMENT AND ANALYTICAL PROCEDURE Apparatus In order to avoid a description of the methods employed in each subsequent paper, a description of the apparatus and the analytical procedure will be given here. The apparatus is shown schematically in Fig. 1. The numbered items in Fig. 1 represent the high pressure valves. The equilibrium cell is of the totally enclosed type, with a volume of 550 cubic centimeters. The cell is mounted in an air bath which in turn is mounted on pillow blocks and connected to a rocking mechanism so that the cell and bath will oscillate approximately 30 degrees above and below the horizontal at 35 oscillations per minute. The air bath is heated by two resistance heaters. The first or primary heater is 250 watts and is controlled by a thermoregulator; the second heater is of 500-watt size and is manually controlled to aid in bringing the cell to equilibrium temperature. Air circulation in the bath is accomplished by means of a fan. the shaft of which is concentric to the heaters. The walls of the bath are insulated with 2-in. thick blocks of 85 per cent magnesia. Temperature observations are made with three calibrated thermocouples. One couple is sealed in a well provided within the equilibrium cell, and is used as the criterion of the cell being at the equilibrium temperature. The other two thermocouples are located on opposite sides of the cell to indicate temperature uniformity within the air bath. The thermoregulator, used in conjunction with a relay, gives a variation in the temperature of the air in the bath of plus or minus one degree Fahrenheit. However, since the equilibrium cell weighs approximately 55 pounds, the

Jan 1, 1950

By M. J. Sinnott, J. C. Tobin

A technique for collecting and analyzing the small quantities of gases desorbed on heating metal powders has been developed. The gases collected from copper powders of various types of manufacture have been analyzed and found to contain H2O, CO2, and SO2. The quantities of gas evolved vary from 0.05 to 1.0 milliliter, under standard con-ditons of temperature and pressure, per gram of powder. The source of the gas has been traced to surface films on the powder. IN the powder-metal industry it is recognized that the presence of gases in the powders affects the processing and resulting properties of the sintered product. Several sources for these gases are possible; namely, chemical reactions with the sintering atmospheres, inclusion. of gases during compacting, dissolved gases in the metal powder, and sorbed gases on the metal-,powder surfaces.1, 2, 3 Since the quantities of the gases are relatively small, no direct attempt has been made to collect and analyze them nor to isolate their source. The work that has been done has been concerned with the dimensional stability of the product., its porosity, density, or mechanical and physical properties. Conclusions are drawn on the basis of studies of this type as to the probable effect of gases on these properties. 4, 5, 0 In the present investigation an attempt has been made to obtain quantitative data on the analysis and quantities of gases associated with copper powders manufactured in different ways. Apparatus was constructed to collect gases evolved from loosely packed powder samples on heating to various temperatures under a reduced pressure of helium. The powders were outgassed thoroughly in a vacuum prior to starting the collection operation in order to eliminate mechanically entrapped gases and to prevent the possible reaction of the powder with these gases. Experimental Procedures Materials—The major portion of the investigation was carried out on a single heat of water-atomized, oxygen-free, high-conductivity copper. A relatively coarse fraction of this powder, 20 to 100 mesh, was tested as a mixed powder and as various graded size fractions. The microstructure of this powder showed equiaxed grains and was clean and free from oxides and oxide eutectic. The particle size, as determined

Jan 1, 1959

By Eldon N. Dunlap

Recently the producing branch of the petroleum industry has shown a considerable and growing interest in the quantitative determination of the water, oil, and gas content of cores as it relates to estimation of reserves, to providing a basis for judging as to the feasibility of applying various secondary-recovery and pressure-maintenance processes, and in general to the operation of producing properties. For years it has been known that oil, gas and water coexisted in the pores of many semidepleted oil measures. It is now generally believed that oil-bearing beds contain connate water in amounts varying up to 50 per cent of the pore space. However, only lately has reliable direct evidence of the extensive occurrence of connate water in oil sands been published. Very little work has been done to ascertain the effect of this water on the productivity and ultimate recovery of oil from wells. It was the intent of this research to study the influence of interstitial water on the flow of oil through unconsolidated sands, with the hope that the results could be applied qualitatively to the flow of oil in underground reservoirs partly saturated with water. Obviously, ultimate recovery estimates based on the void volume of the reservoir will be in error unless a correction is made for the volume of water that occupies a portion of the effective pore volume of the reservoir. Evaluation engineers in the past have applied arbitrary saturation and recovery factors that may inadverently have compensated for the failure to consider specifically the water content. Nevertheless, the evidence available indicates that these factors need revising if each is to be independently correct and truly representative. Although the fact that the connate water renders part of the pore volume of the reservoir incapable of containing oil is of primary importance to the operator, it is also to his interest to know to what extent the presence of varying amounts of interstitial water influences the permeability of the sand to oil.

Jan 1, 1938

By P. Nyul, S. Caplan, M. F. Lamorte, T. Gonda

Therrnal resistance is measured on GaAs laser diodes in the temperature range 77" to 300°K. These data show that typically the thermal resistance increases fifteen times from 77 to 300°K. The increase is attributed to the decrease in thermal conductivity of Gds. Nornzalized thermal-resistance experimental and calculated from published thermal-conductivity data) values are compared and good agreement shown. In many practical applications, it is desirable to obtain high average power output from laser diodes. Average power output is determined in large measure by the external efficiency and thermal resistance of the diode.'-3 The average input power with which a laser diode may be pumped is dependent on the thermal resistance. Thermal resistance has been studied over the temperature range from 77" to 300°K which is usually of interest in practical applications. This correspondence presents data on thermal resistance for GaAs laser diodes and compares them to values calculated from thermal-conductivity data. Junction heating arises from three distinct components: 1) joule heating, 2) nonradiative recombinations, and 3) reabsorption of radiation. In high-threshold lasers, joule heating predominates.4 Typically, the nonradiative recombination is not negligible and contributes significantly to junction heating. The loss caused by reabsorption may be of the order of the joule-heating loss.' The fabrication and the geometry of laser diodes have been described in other publications.5 The data presented were obtained from diodes which were fabricated from the same region of a wafer to minimize differences. Fig. 1 shows four types of heat sinks employed in this study. In types 1 and 2, the laser cavities are alloyed; pressure contacts are employed in types 3 and 4, and indium is plated on the inside faces to improve the intimacy of contact between the diode and the heat sink. The thermal resistance R is defined by the following relationship: where AT is the junction-temperature rise above the heat-sink temperature for the diode power dissipation Pd. For measurement of thermal resistance, a direct current is passed through the junction, in the range from 1 to 50 pct of threshold. The diode is placed in the laser mode by superimposing a current pulse of low-duty cycle on the direct current.3 Junction-temperature rise is obtained from the time-resolved laser spectrum at the leading edge of the current pulse.' Typically, the laser line shift is 2.5A per OK. The resolution employed in these experiments is 0.5A; therefore, the accuracy in the temperature measurement is 0.2K. Typically, the temperature rise is 2" to 20°K. The power dissipation is the difference between the dc power input, and the radiation power exiting the diode. The measurement accuracy is less than 1

Jan 1, 1968