Search Documents

By Robert E. Bush, E. S. Mardock

The object of this paper is to report recent developments in the quantitative interpretation of radioactivity logs. The use of reference lines is described in the application of the new zero radioactivity reference line for the determination of neutron derived porosities is discussed. Illustrated examples are shown of logs from the reef limestone of the North Snyder Field and from the Lansing-Kansas City limestone of central Kansas. A method of using an interrelation factor calculated from the neutron and gamma ray curves, called the neutron Productivity number, for the estimation of productivity from sandstone formations is discussed. When used in a relative manner the neutron productivity number has aided in Predicting whether a given zone will produce gas or liquid or whether it is too shaly to produce. Examples of logs from wells in the Freites District, Venezuela, and in East Texas are shown to illustrate the application of the neutron productivitv number. INTRODUCTION The petroleum industry was introduced to some of the preliminary results of investigations into the quantitative interpretation of radioactivity logs in October, 1949." It was stated at that time that the methods presented were entirely relative because they involved the use of reference points obtained from the radioactivity log, i.e., shale reference lines, dense zone reference lines, or a combination of both shale and dense zone reference lines. These relative methods offered many advantages to the industry in interpreting radioactivity logs in terms of porosity with particular application to limestone and dolomite reservoirs. However, these relative methods did not offer the wide range of applicability desired because the esta1)lishment of reliable reference points from shale in some areas were difficult. It was recognized that a more reliable mean; of establishing reference lines was vitally needed. Such a method is now available through the introduction of an instrumeutal zero device. It is the purpose of this paper to discuss the application of this new zero reference to the quantitative interpretation of radioactivity logs. Previously all applications of quantitative interpretations of radioactivity logs have been made in limestone reservoirs with little or no emphasis placed on sandstone reservoirs. A brief resumé of investigations into the quantitative interpretation of radioactivity logs in sandstone reservoirs is presented here. This discussion deals primarily with the interrelation of the gamma ray and neutron curves and the response of the latter to the density of the fluids filling the pore space in relatively homogeneous sandstones of uniform porosity. The authors believe that the methods presented herein are only applicable locally to specific fields and reservoirs, and that they probably do not offer a wide range of applicability. However, tile authors believe that the wider use of the new instrumental zero references in sand areas will reveal more information about the specific response of the gamma ray and neutron curves to changes in lithology and saturation. Two applications of quantitative interpretation using the new instrumental zero references are presented. Examples are given which show the comparison of logs and porosity in the limestones and dolomites of West Texas and Kansas. Logs of wells in 'Venezuela and East Texas are compared with the drill stem test data, production data, etc.. to illurtrate the interrelation of the gamma ray and neutron curve: and the rise of methods involving these interrelations to determine certain saturation variables. THE QUANTITATIVE APPLICATION OF RADIOACTIVITY LOGS TO LIMESTONE AND DOLOMITE RESERVOIRS Tile theoretical basis for the gamma ray and neutron curves has been discussed elsewhere.9 he method of recording the logs and apparatus involved has also been thoroughly covered and will not be discussed here.'."".'" It has been shown that the neutron curve responds exponentially to liquid filled porosity over the 1 1/2 to 35 per cent

Jan 1, 1951

By F. D. Rosi, C. H. Mathews

THE plastic properties of face-centered cubic metals below room temperature present a field of investigation which has not been extensively ex-plored. The work by Schmid and Boas1 has demonstrated the importance of temperature upon such properties as strain hardening and critical resolved shear stress. The work by Yamaguchi2 upon the shear stress as related to the number of slip bands accentuates the necessity for further experiments of a similar nature. The approach to a mechanical equation of state from the standpoint of thermal fluctuations and activation energies by Becker3 and more recently by Kauzmann4 further emphasizes the need for a quantitative and more comprehensive analysis of the dependence of fundamental plastic properties on temperature. The purpose of the present work was to investigate specifically: (1) The gross shape of the stress-strain curves at several temperatures, (2) the change in the critical shear stress as a function of temperature, and (3) the number and appearance of slip bands as a function of strain and temperature. Preparation of Specimens Single-crystal specimens of 99.996+ pct alumi-num, 1/2 in. in diam and 5 to 6 in. in length, were made by the Bridgman method of gradual solidification from the liquid state. The crystallographic orientation of the single crystals was determined from back-reflection, Laue X-ray photograms ac-cording to the method described by Greninger.6 In most specimens the Laue photograms showed double diffraction spots indicative of the lineage structure type of imperfection, discussed in great detail by Buerger.7 The angular spread of these spots was never observed to exceed 2". Most of the crystals were radiographed to insure against microporosity. In preparing the metal surface for optical microscopy, the following sequence of operations gave good results: The as-cast crystals were turned down in a lathe, 0.001 in. per cut, to obtain a 2.5 in. gauge length. The cold-worked layer resulting from this operation was removed chemically by etching with Tucker's reagent. Then the specimen was polished mechanically through 2/0 metallographic emery paper, after which it was etched again to remove the cold-worked layer resulting from the mechanical treatment. A 48-hr anneal at 580°C ±10°C followed so as to insure an essentially stress-free single crystal. After the annealing treatment, the specimen was electrolytically polished in a 2:l solution of methyl alcohol and concentrated nitric acid. With a current density of 10 amp per sq dm (decimeter) the time required to obtain a satisfactory surface varied from 10 to 12 min. The polish-ing was carried out for short periods of 2 min to avoid rapid deterioration of the solution as well as to enable the rotation of the specimen 180" for uniformity of polish. It was necessary to place the solution in a bath of dry ice in view of its explosive nature at room temperature. Etching of the electrolytically polished surface was accomplished by using the fuming etch-pit method recommended by Lacombe and Beaujard8 for high-purity aluminum. Method for Tensile Testing A modification of the loading equipment devised by Miller9 was used. In this apparatus, the specimen was suspended from a chain and gimbal arrangement (for axial loading) in a heavy steel framework connected at the bottom to a balanced 6:1 lever and bucket system. Loading of the specimen was accomplished by allowing sand to flow from a reservoir into the bucket suspended from the longer end of the lever-arm at a rate of approximately 3 lb per min. Strain measurements were made using the Baldwin SR-4, bonded, resistance-wire, strain gauge and an SR-4 portable strain indicator (type K), which permits a reading accuracy of 2 microinches per inch. For low-temperature study, the gauge was calibrated by measuring the elastic modulus of an annealed stainless steel rod, which is known to be independent of temperature."

Jan 1, 1951

By H. T. Clark

NO previous determinations of the deformation or recrystallization textures of titanium or of titanium-base alloys have been reported in the literature. The room-temperature structure of titanium is hexagonal close-packed with a c/a ratio less than 1.633. It would be expected, therefore, to have a rolling texture similar to that of other hexagonal close-packed metals, namely (0001) [1010]. Burgers and Jacobs1 have shown that zirconium, a metal isomorphous with titanium in its structure and similar in many of its properties, has such a texture with a scatter of the basal plane toward the transverse direction. This scatter is in the opposite direction from that found in magnesium by Bakarian2 but similar to that reported by Smigelskas and Barrett3 or beryllium. The rolling and annealing textures reported here for high-purity iodide titanium are significantly different from the . textures of any other hexagonal close-packed metal. All titanium used during this investigation was prepared by the iodode process." The annealed hardness of this material varied from 73 (material used for sample No. 2) to 97 Vickers hardness number. An estimate of the chemical composition of this grade of titanium has been reported by Finlay and Snyder.5 With one exception, shown in table I, the as-deposited titanium was cast into 10 to 20 g ingots in an electric arc furnace in purified argon before being rolled to sheet. The cast ingots were forged and ground until their cross-section was approximately rectangular, annealed 1 hr at 700°C in vacuum and cold rolled. Rolling was carried out in a two-high, 4 in. diam mill, using reductions no greater than 10 pct per pass. The direction of rolling was reversed after each pass, and, in order to avoid temperature effects, the sheet was allowed to cool after each pass. Unless the rolled sheet was sufficiently thin for X-ray penetration (about 0.004 in.), it was reduced to this thickness by pickling. Because of the possibility of introducing twinning or other deformation during grinding, no attempt was made to maintain uniform thickness of the sample during pickling by intermediate grinding or sanding operations. Those samples to be used for determining the annealed texture were recrystallized by vacuum annealing the cold-rolled sheet for 1 hr at 500°C. These thin samples were held between thick titanium sheets during annealing to prevent distortion. Table I outlines the rolling and annealing schedule of those samples for which photograms or texture patterns are shown. X-ray Techniques The usual techniques for determining textures were employed during this work. Molybdenum radiation was used for the transmission exposures and copper radiation for the glancing angle ones. Since titanium fluoresces under these conditions, it is necessary to employ a filter between the sample and the film. The Kß radiation filters are very satisfactory for this purpose. Sufficient grains having favorable orientation were present in both the cold-worked and in the cold-worked—500°C annealed samples to provide satisfactory patterns with the samples stationary. Because of the difficulties of comparing intensities of transmission photograms with those obtained

Jan 1, 1951

By R. S. French, W. R. Hibbard

FOR tensile deformation, if the stress value is defined by the ratio of the load to the actual area, and the strain value by the natural logarithm of the ratio of the immediate length to the original gauge length of the sample, the resulting data when plotted with logarithmic coordinates result in a linear relation extending from the initial plastic yielding through the maximum load and in some cases, such as for copper and brass, to fracture'.'. The normal form of the curve, therefore, is a parabola, satisfying the following equation: S = Kem [1] where S and e represent true stress and strain, K is a constant, and m is a coefficient evaluating the slope of the curve and designated therefore as the strain hardening coefficient. Hollomon² has reported that this coefficient is a function of the yield strength as effected by grain size in alpha brass, and the carbon content and heat treatment of steel. In the case of steel, the value of the proportionality constant is a function of the carbon content. It was further shown in that paper2 and also by Low and Prater -hat, if the power relation between stress and strain remains valid, the strain hardening coefficient m, is equal to the strain at the maximum or necking load. Thus, an added significant feature is that this coefficient may serve as an index of the capacity for deformation prior to localized necking and subsequent fracture, e.g. drawability. The constant K may be defined as the strength of the material at unit strain. Together the K constant and the m coefficient describe an alloy's physical properties as far as strength and ductility are concerned for a particular yield strength and, in the case of steel, a particular carbon content. The work of Lacy and Gensamer4 gives data on alloy ferrites from which very close estimates of the strength of ternary and higher iron alloys have been made. It was the purpose of this investigation to develop similar data for commercial copper base alpha solid solution alloys. Preparation of Specimens Commercial binary alloys of copper with aluminum, beryllium, cadmium, nickel, silicon, tin and zinc were investigated. In addition, laboratory castings were made of a 1 pct silicon alloy and a 2 pct aluminum alloy to complete these particular series. Two types of copper were used, oxygen free OFHC and tough pitch FC. The analyses of these alloys are shown in table I. Standard ASTM sheet tensile specimens were used to determine the usual physical properties of each alloy and to obtain stress data at strains from 0.0005 to 0.01. Small (1/4 in. x 3 in. x tk.) samples

Jan 1, 1951

By E. E. Schumacher

IN a laboratory devoted to the furtherance of the science of communication, the breadth and variety of the problems encountered are challenging to a metallurgist. In my own long association with the Bell Telephone Laboratories, our metallurgical group has dealt with a vast number of alloys, both ferrous and nonferrous, and with many materials in the border range of metallic properties., The objectives of our design engineers embrace every phase of telephony, and the properties they desire in metals are generally unusual, frequently unique, and often conflicting. Commercial alloys have not always been available with properties to meet a special requirement in the telephone plant, and many alloys have had, therefore, to be custom-made. Anyone who has had the opportunity to observe the results of tests of all types on numerous such alloys, both commercially and specially produced, or who has taken part in the development of an alloy of some necessary, but new or unusual combination of properties, could not fail to be impressed by the frequency with which a desired goal has been reached or adequately approached through the presence of decimal quantities of alloying elements. Nor could One fail to be struck by the occasions when, conversely, of a minute amount Of impurity element has rendered an alloy useful. It is no exaggeration to state that the content be- hind the decimal point often spells success or fail-ure, and the critical content is sometimes far to the right of the decimal point as I shall later illustrate. The great effects of small additions have long been recognized and have, in fact, been described by many investigators. The importance of the minute, however, cannot be overemphasized. Therefore, in this discussion, I propose to illustrate for you some of the startling instances, drawn primarily from our own experiences, wherein small, even vanishingly small, proportions of stranger elements in otherwise common aggregates have com-pletely changed the customary pattern of behavior. No one property has a monopoly as to being dis-proportionately affected by minor elements. Nearly all properties are affected, but there is time here to include only a selected few. I have chosen, there-fore, three of general interest: strength, magnetic, and electrical properties. I shall inquire into both the mechanisms and consequences of these disproportionate effects and try to share with you the fascination and challenge of this field. Strength Properties of Lead and Lead Alloys To illustrate the effect of the minute on strength properties I have selected lead and its alloys, with which we have worked extensively for many years. Lead has the advantages of being available in quantity in a state of high purity and of being fairly easy to melt and fabricate without contamination to any extent detectable by the spectrograph. It has the interesting disadvantages of recovery and recrystallization at room temperature. Whether I

Jan 1, 1951

By W. Keith Buck

Introduction During World War II years, the magnetometer was used by various field parties of the Geological Survey of Canada, specifically in the search for chromite, a strategic war mineral. Throughout the summer of 1944, Professor J. W. Ambrose used the instrument experimentally on eight separate projects (1). Since then, several members of the Survey have come to consider its use to be of valuable assistance in the season's mapping. Dr. C. H. Stockwell, in particular, regards use of the magnetometer as a necessary part of detailed geological survey work. Throughout the field season of 1949, the magnetometer was used by Dr. Stockwell?s party as an aid to mapping in detail, to the scale one thousand feet to the inch, the south-west quarter of Dasserat township, Temiskaming county, Quebec. The principal geophysical project that was undertaken was the location of the Horne Creek fault and the Diabase fault in the area approximately midway between Arntfield and Kearns, on the Quebec side of the Interprovincial border. The location of these faults on either side of this central area was known. The Horne Creek fault is a subsidiary fault to the Cadillac 'break' which extends ?westward from Val d'Or through Cadillac to beyond Larder Lake. It lies to the north of that major fault zone and has a general southwesterly trend.

Jan 1, 1951

By P. P. Scott, George C. Howard

During the drilling of wells, fractures which are created or widened by drilling fluid pressure are suspected of being a frequent cause of lost circulation. A study of the variables which are believed by the authors to he related to fracturing led to the premise that the presence of an effective lost circulation material in a drilling mud stream would serve to plug small fractures at the moment they are encountered or created and thereby a a possible cause of lost Circula. tion by preventing fluid pressure from widening and extending the fractures. A large number of lost circulation materials were classified and tested in simulated fractures and in shallow wells. Granular type materials with a gradation of particle sizes were found to be the most effective for plugging. Within the limits of pumpahility, the concentration in mud of each lost circulation material tested was found to be a controlling factor in determining the maximum size fracture which could be sealed. A new type centrifugal sorter was given preliminary tests and found to be capable of concentrating cuttings for rejection and reclaiming lost circulation materials. INTRODUCTION The control and prevention of lost circulation of drilling fluids is a problem frequently encountered during the drilling of oil and gas wells. Lost circulation or lost returns may be defined as the loss to formation voids of the drilling fluids or cement slurries used in the process of rotary drilling and well completion. The loss may vary from n gradual lowering of mud level in the pits to a complete loss of returns. Not to be confused with lost circulation is the continuous reduction in mud volume caused by the loss of the fluid phase of muds as filtrate and the solid phase as filter cake during the continuous filt~ation process which occurs on permeable formation surfaces. The loss of drilling fluids and their costly constituents is only one of the detrimental effects experienced when circulation is lost. The loss of drilling time, plugging of potentially productive formations, stuck drill pipe, blow-outs, excessive inflow of water, and excessive caving of formatioils are other effects which contribute to make the control and prevention

Jan 1, 1951

Magnetic methods have for a long time been used in the search for iron ore. In fact the first recorded geophysical prospecting was the use of a magnetic compass to locate iron ore in the Kuruna region in Sweden as early as 1640.The largest magnetic anomaly discovered, about 700,000 gamma-s, is in this region.The enormous deposits in Russia in the Kursk region, where the ore consists largely of magnetite, were discovered by magnetic methods. Heiland estimates the proved reserves at 290,000 million tons and the additional potential deposits at twice this amount.These magnetite ores Show extremely high magnetic anomalies and consequently very insensitive instruments could be used to survey them. The first aerial magnetic surveys were carried out in this area in 1928.Large areas of the iron ore producing regions in Norway, Sweden and the United States have been covered by magnetic surveys in the past 30 years, much of the work being started after the first World War.In every major iron ore producing country, except Australia, extensive magnetic surveys have been, or are, carried out with the purpose of extending the reserves of ore. Australia is indeed fortunate that the depletion of iron ore reserves and the location of new deposits has not become an urgent problem. Nevertheless, some minor reconnaissance work has already been carried out in Australia, and the Commonwealth Bureau of Mineral Resources, Geology and Geophysics is contemplating a more extended aerial magnetometer survey in the Middleback Ranges area. The work so far done in the Middleback Ranges country consists of a ground magnetic survey of a few small...

Jan 1, 1951

By R. E. Zimmerman

Wide attention is being placed upon various methods for cleaning the fine sizes of bituminous coals. The author describes and analyzes the results achieved on wet concentrating tables of modern design on unclassified feeds of —Vz in. particle sizes, including tests on high-sulphur coals. THE increased economic necessity of cleaning the small sizes of coal has forced wide attention upon various methods or processes being used. Although numerous cleaning plants in the past have been cleaning coal smaller than Vz or % in., the large quantities of higher ash fines being produced by mechanical mining and the need for cleaner coal under competitive market conditions have brought about many new installations of fine-coal cleaning plants. Of various methods used, one of the more popular types is the wet concentrating table. Approximately 525 tables have been installed in the United States in the past four years of which 320 have been installed in 20, large new plants. There are now probably 1600 tables of all types in existence in this country for cleaning coal. The purpose of this paper is to describe the cleaning of fine coal by wet concentrating tables. Its scope is confined to a discussion of the theory of tabling and some of the factors entering into tabling action, a description of the Deister SuperDuty diagonal-deck coal table and a discussion of the results of tabling various fine sizes of coals. Al- though tables have been used for cleaning coal as coarse as 2 in. and favorable results are reported, this paper is limited to reporting on the results of cleaning coal fines from 1/2 in. down. Also, although it is well known that the performance of tables is even superior under classified or closely sized feed conditions, this paper concerns itself with the results achieved by tabling unclassified feeds. History of Wet Concentrating Tables The wet concentration of minerals by some form of tabling is quite old, starting originally from fixed, smooth surfaced, tilted boards taking advantage of the laminar flow of liquid films and the separation of minerals according to specific gravity. This was followed by the development of rough deck surfaces

Jan 1, 1951

By J. L. Wyatt

THE smelting of ilmenite to produce a slag rich in titanium, with pig-iron as a byproduct, introduces new concepts in electric smelting metallurgy. Titanium slags are characterized by low electrical resistance, thereby requiring a different type of electric furnace operation, and power supply sources substantially different from those encountered in normal steel melting and siliceous ore smelting furnaces. This paper describes special apparatus for determining specific electrical resistivity of titanium slags, and reports the values obtained on slags encountered in the process of smelting ilmenite ores. In an induction furnace under conditions approximating normal furnacing operation, 25 general heats and 6 special standardization and comparison heats were run. Results indicate relatively low resistivity. Resistivity depends primarily on slag composition, and, to a lesser degree, on temperature. During the summer of 1947 a cooperative project between the National Lead Co. and the Bureau of Mines was conducted at Boulder City, Nevada, in the Electrometallurgical Laboratories of the Bureau. The project involved smelting of ilmenite ores in electric furnaces, and has been reported in detail.' The author participated as a member of the staff of the National Lead Co. during the entire campaign. One outstanding characteristic of the titaniferous slags, their apparently excellent and variable electrical conductivity, was considered sufficiently important to warrant further study. Although little electric smelting of iron ores has been done in the United States, a certain amount of information is available for comparative purposes. Personal experience in smelting siliceous iron ores in electric furnaces furnished further information for comparison. In general, silicate slags are relatively poor conductors of electricity. Current flow during smelting operations may be maintained through a floating layer of coke on top of the slag bath, or through a bath of molten iron, beneath the slag. Silicate slags are not sufficiently conductive to furnish a path for current passage when normal furnace voltages are used. Experimental smelting of a silicate iron ore was undertaken for comparative purposes. A fluid melt was not obtained until the FeO content was reduced to 15 pct. The resistivity increased as the FeO content decreased, FeO compounds being the most conductive of the various oxides in such a normal slag system. The converse appears to be true in slags containing large percentages of TiO2. It has been found that titanium slags become molten with FeO percentages in excess of 30 pct, and that the conductivity becomes generally better as the FeO con-tent of the slag diminishes. This phenomenon was demonstrated in the furnacing operations at Boulder City. During the initial smelting period furnace electrodes could be held immersed several inches in the slag, with tap selectors set for a no-load voltage of 70 v. As the FeO content decreased, the furnace electrodes would "walk up," until at one point in the process the tips would break the surface and arc on top of the slag. This was undesirable since direct arcing caused losses of important flux additions. The slag compositions under study at that time were such that losses due to surface arcing sometimes caused viscous slags to be formed. Forcing the electrodes into the slag bath by manual control to prevent surface arcing resulted in excessive power input and lack of control. Suitable low voltages were not available. Measurement of the electrical resistivity of titanium slags at various operating temperatures and slag compositions was undertaken. It was believed that this information would be of use in the design of electric furnaces suitable for smelting ilmenite, with voltages, electrode sizes, and electrode spacing adapted specifically to titanium slags.

Jan 1, 1951

By J. E. Burke

THE origin of so-called annealing or recrystalli-zation twins in face-centered-cubic metals continues to be a matter for speculation, and in the present report an attempt is made to explain their origin and to account for at least a majority of the observations concerning their behavior. The fact that annealing twins are prominent only The speelmen was deformed 8 pet in compression and then indented over the lower left-hand corner in a Rockwell in-denter, and then annealed to cause partial recrystallization. Note intense twinning in heavily deformed part and slight twinning in less deformed part. The upper right-hand corner is unrecrystalized. Area reduced approximately 25 pot for reproduction. after recrystallization suggests that deformation may be necessary for their formation. In 1926, Mathewson1 reported the observation by Phillips that annealing twins are frequently parallel to strain markings which delineate octahedral planes in the deformed (and partially recrystallized) matrix, and suggested that strain markings are mechanical twins which grow into annealing twins during recrystallization. Later work by Burke and Barrett' has shown that strain markings are traces of planes upon which slip has occurred, and that there is no evidence for the formation of mechanical twins of microscopically resolvable width in face-centered-cubic metals. Mathewson3 has pointed out, however, that slip may produce twin faults, and later modifications of this hypothesis have assumed that twin faults rather than true mechanical twins serve as the nuclei for annealing twins. Carpenter and Tamura5 suggested, also in 1926, that annealing twins might form by accidents of growth. A close-packed layer of atoms can be added to the octahedral plane of a face-centered-cubic metal in two possible positions, the right position

Jan 1, 1951

By C. E. Birchenall, H. M. Schadel

THE purpose of this study was to measure the vapor pressure of silver as the first step in the determination of activities in silver alloys and to test the limitations of the method adopted. In order to work at low pressures, below 2x10-2 mm of mercury, the orifice effusion technique was employed. To shorten the time of collection of silver from the atomic beam, radioactive silver (Ag110) was used as a tracer. The rate of effusion of a monatomic vapor from an "ideal" orifice, where the thickness of the orifice edge is negligible compared with the orifice diameter, can be readily calculated from the kinetic theory of gases, G = vM a p/v2pRT where G is the weight of material effusing from the orifice per unit time; p is the vapor pressure at oven temperature, T; R is the gas constant; M is the molecular weight of the vapor; and a is the orifice area. Consolidating constants and expressing as the weight of material effusing from the orifice in a period of time, t, (5.83)(10-2) (vM) (a) (t) (p)/vT where GT is total weight of monatomic vapor effused (g); M is molecular weight of the effusing tracer vapor; a is orifice area (cm2); t is time of effusion (sec); p is vapor pressure of effusing material (mm of Hg); and T is oven temperature (OK). The vapor effuses from the orifice in a hemispherical pattern, and the intensity of the beam in any direction is given by the cosine distribution law.' Considering this, the weight of effused material can be calculated from the amount of material passing through a circular collimator intersecting the beam. If such a collimator is in a plane parallel to the plane of the orifice and with center on the normal to the orifice center, GT = G?/1-cos2? = G?/sin2? where G? is the weight of effused material passing through the collimator, and 0 is one half the apex angle of the cone defined by the collimator circumference and the orifice center. Reducing eq 3 to the more directly measurable quantities of orifice to collimator distance, d, and collimator diameter, D, the expression becomes,

Jan 1, 1951

PRESIDENT Mrs Oliver Bowles 5000 Massachusetts Avenue N W. Washington 16, D C FIRST VICE-PRESIDENT RECORDING SECRETARY Mrs David E" Park Mrs Thomas T Read 115 East 67th Street 9 Windmill Lane New York 22, N Y Scarsdale, N Y

Jan 1, 1951

By M. G. Zabetakis

Benzene and toluene are the first two members of an important homologous series whose general formula is CnH2n-6. The members of this series differ in composition from benzene by some integral multiple of CH2; they can all be prepared in the laboratory by the Wurtz-Fittig, Friedel-Crafts and Grignard syntheses. Because 'of the industrial importance of these-hydrocarbons, the limits of flammability of eight members of the series have been determined at 100° C.-(A temperature of 1000 C. was chosen because the determination of the upper limit of flammability of p-cymene requires an apparatus temperature. of at least 90° C. As elevated temperature data are available for other combustibles at 100° C. but not at 90° C., all data were taken at 100° C. in order to obtain comparable results.) Minimum ignition temperatures of these combustibles have been determined at laboratory-pressures.

Jan 1, 1951

By H. Kenworthy

Small batches of fluorspar flotation concentrates were made into nodules and pellets on a laboratory scale. Several of these were rated acceptable by laboratory evaluation methods. The most satisfactory pellets were produced by mixing fluorspar with about 12.5 percent of water, by weight, and 4 percent of organic binders. These binders) for the most part) originated from petroleum and wood-pulp industries. They were generally difficult to handle and were not easily incorporated with the fluorspars tested. Most of them seemed to have an aversion for damp fluorspar and had to be forcibly mixed with the fluorspar; which was then formed into pellets by pressure. Substitution of fuel oil in varying amounts in the binders enhanced the mixing and penetrating qualities of these binders but at the same tire tended to make the pellets more porous. Tall oils performed the same function to a lesser degree and usually decreased the water absorbency of the finished pellets. Heat-treating temperatures to set up these binders were moderate -about 5000 F. for 30 to 50 minutes was usually enough for both drying and heat treating. Nodules made with 1-1/2 to 2 percent of bentonite as a binder were easily mixed and formed. They required a high degree of heat (about 1,500° F.) to develop their strength and were quite water-absorbent when finished. Two fluorspars were examined for weight and fluorite loss after heat treatment at similar temperatures. Both showed a definite wej.ght and analytical loss of fluorite. Bentonite was used also as a binder to successfully nodulize finely ground oxides of iron, manganese, and nickel.

Jan 1, 1951

By A. R. Elsea, C. C. McBride

HIGH-TEMPERATURE alloys, that is, alloys that are strong at high temperatures, have become increasingly important with the development of modern aircraft engines. Many alloys of this type are available. However, metallurgists do not have a clear understanding of the phases or structures which are responsible for these high-temperature properties. If these basic factors were understood, it might be possible to make better or cheaper alloys for service at high temperatures. For this reason, an investigation of the fundamental factors promoting high-temperature strength in alloys was started at Battelle Memorial Institute. This was to have included a study of the relationship between the structure and properties of cobalt-chromium base alloys of the vitallium type. It soon became clear that the structure of vitallium is quite complex and that the equilibrium diagrams which should explain these structures were unreliable. As a result, the cobalt-chromium binary diagram was determined as the first phase of this investigation1. This diagram is shown in fig. 1. During the study of the cobalt-chromium binary system, it was learned that these alloys may pick up considerable nitrogen when melted and heat treated in air. The extent to which nitrogen affects the various reactions in cobalt-chromium base alloys was not known, but there were indications that this impurity might be responsible for some of the erratic test results obtained for vitallium. Consequently, nitrogen was the first ternary addition studied. Thereafter the work was extended to ternary additions of iron and of nickel. This paper describes the investigation of the effects of nitrogen, iron, and nickel upon the reactions in cobalt-chromium alloys with 80:20 and 68:32 cobalt-chromium ratios. Experimental Work Alloy Preparation: A series of cobalt-chromium base alloys containing various amounts of the third element being studied were made for both the 80:20 and the 68:32 cobalt-chromium ratios. Electrolytic chromium, cobalt, and iron, and reagent-grade nickel powder were used as melting stock. Table I contains the chemical analyses of these materials. The charges were melted in alun-dum thimble crucibles which absorbed chromium oxide and effectively deoxidized the melts. These crucibles were supported by close-fitting graphite sleeves so that if they cracked during melting the metal would not be lost. Carbon increases, during

Jan 1, 1951

By Jr. Brinkley

For a theoretical description of power plants that derive their energy from the combustion of a fuel, it is necessary to solve, to an appropriate degree of precision, a hydrodynamic problem that requires for its solution a knowledge of the thermodynamic properties of the working fluid com-posed of the products of the combustion reaction. It is usually a good approximation to assume that the properties of the combustion gas are determined by the conditions of thermal equilibrium, and it is thus possible to employ the methods of Classical thermodynamics for their computation. The thermodynamic properties of fuel gases also are of considerable importance, as they form the basis for the design of appropriate means for their effective utilization. The specification of the operating conditions to produce a gas for use as an intermediate in a chemical process, such as the synthesis of liquid fuels, may be based upon a study of the variation of the composition of the synthesis gas with changes in the various process variables. Although there exists a large number of important scientific and technical applications of the data that can be obtained from the systematic determination of the thermodynamic properties of combustion gases, such application has been greatly handicapped by the extremely tedious and time-consuming computational methods required. The development of large-scale automatic computational equipment makes feasible the initiation of a systematic program for the determination of the thermodynamic properties of combustion gases and for the application of such data to specific problems of scientific and technical importance. As a part of its program of basic research in flame and combustion phenomena, the Explosives and Physical Sciences Division of the Bureau of Mines is engaged in such a program. The present communication is designed to introduce a series of reports presenting the results of this program.

Jan 1, 1951

By Brahm Prakash, R. Schuhmann

Maurice Rey—It may be interesting to note that depressing effects can also be obtained from cyclic compounds other than dyes. One such compound which is a dispersing agent for carbon, pigments and other compounds is known in France by the trade name "dispergine" and in the United States by the name of Lomar P W (Jacques Wolf & Co.) Dr. Rey admits that the compound is not very selective and is similar in its action to starch and dextrin.

Jan 1, 1951

By Shiou-Chuan Sun, R. F. Wesner, J. D. Morgan

FOR successful electrostatic separation, the behavior of the component minerals of the tested ore under various conditions should be known. In the course of investigation, it was found that these are difficult to measure accurately by the presently available methods. The method used by Johnson1 is handicapped by the fact that particles in the extreme front and rear end of the falling stream are difficult to control or observe accurately. Furthermore, this method is not applicable when the tested sample consists of more than one mineral. The deflection method, as reported by Fraas,' is inadequate to show the differential amounts of mineral particles deposited at the various horizontal positions under the grounded roll of the separator. This weakness is further noted when the tested sample contains more than one mineral. The purpose of this paper is to introduce a new method capable of measuring the behavior of mineral particles under various conditions, and of defining the optimum condition for separation. The main factors which influence the behavior of mineral particles in electrostatic separation are also described. dividing gauge and the two attached collecting chutes of a Johnson separator.~ This distribution analyzer consists of sixty or more 1.0-cm wide cells as shown in part in fig. 1; it has been fully described in a previous article." Except where otherwise stated, the testing procedure used in this paper is as follows: (a) calculate the weight of feed for a l-min run at a constant feed rate of one layer of closely packed particles falling on the grounded roll; (b) weigh and dry the feed at 100°C for 12 hr; (c) place the top of the distribution analyzer level 4 cm below the bottom of the grounded roll, so that the cells are longitudinally parallel to the grounded roll and the zero edge of a suitable cell is directly under the front vertical tangent to the grounded roll (see fig. 1); (d) with the charged roll at a negative potential of 15.5 kv, the dry hot sample is introduced into the feed chute at a constant feed rate; and (e)

Jan 1, 1951

By M. P. Tixier

Abstract In a review of the application of electrical logging in Canada, examples are .given of long and short distance correlations by means of the electrical logs. The use of MicroLogging for the determination of permeable and porous formations is explained. The question of log analysis for the quantitative determination of fluid saturation and porosity is .discussed. An example is provided to illustrate the significance of the resistivity gradient. The advantages of the new method of the Laterolog are shown, chiefly for the case of wells filled with high-salinity mud. Introduction Electrical logging techniques developed rapidly in Canada at the time an intensive drilling activity started for the exploitation of the Devonian series in Alberta, namely, at the beginning of 1947. The conventional service was soon thereafter supplemented with the latest technica1 improvements. Canada has been among the first regions to take advantage of MicroLogging*, which has proved a most powerful .tool for the investigation of permeable and porous formations; also, the more recent development known as the Laterolog has ?been introduced in Canada. The Laterolog provides a better determination of .the formations, particularly in the case of salty mud where the conventional logging is greatly handicapped. The various methods of electrical logging are now commonly known in oil industry and have been described in numerous publications ( 1) ( 2) (3).

Jan 1, 1951