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By H. J. Beach

This paper describes the properties and uses of cementitious mixtures containing 10 to 20 per cent bentonite and 2 per cent or more sodium chloride. Salt additions improve bentonite cement by increasing early strength and stabilizing viscosity without changing thickening time. The volume yield of cement is increased 20 per cent or more without lowered early strength. The unique properties of salt in this type of system make savings of more than 10 per cent possible where light-weight, low-strength cementitious material is adequate to fill behind pipe. The density range of these mixtures is 12 to 13 1b/gal and the filtration rates are medium-low, aiding the placement of long columns in primary cementing. Where available, sea water is an ideal salt source in preparing these slurries. INTRODUCTION Accelerators increase the rate of cement hydration. In speeding reaction with water, they can affect cement performance by reducing thickening time and increasing early strength after set. Accelerators that cause both effects can be considered "total", and those which produce only one effect can be called "partial". Materials that act conversely to accelerators are retarders. and they also can be total or partial. Partial retarders. make high-temperature cementing possible by prolonging thickening time while impairing early strength only slightly. Most known accelerators are total. A useful partial accelerator would increase strength without altering thickening time. This report concerns material combinations in which a normally total accelerator exerts unique partial properties. Utilizing these limited effects improves bentonite cement. SEPARATE EFFECTS OF SODIUM CHLORIDE AND BENTONITE ON CEMENT Sodium chloride and calcium chloride are commonly used in cement, and at low concentrations their effects are similar. Ludwig1 studied sodium chloride in API Class A and Class E cements.' Figs. 1 and 2 sum- marize his data taken at 140°F on slurry pumpability and early strength. Normal water-to-cement ratios are 0.46 and 0.40, respectively, for Class A and Class E cements. At saturation the salt content is 12 to 14 per cent of the weight of cement solids. The illustrations, therefore, cover the range of salt solubility in the mixing water. The data show that sodium chloride is a total accelerator of the Class E cement studied over the range of solubility. It is total in Class A cement to 6 per cent. Above this concentration salt becomes a retarder— partial from 6 to 10 per cent and total above. These results are general for different brands of Class A cement, although the shift from acceleration to retardation may occur at different salt concentrations for different temperatures. The results are specific for the Class E brand studied. In discussing his data, the investigator emphasized that different Class E cements might respond erratically to salt, depending on the brand chosen. Morgan and Dumbauld3 escribe the properties of bentonite cement in a paper that is a standard reference in using these systems. Bentonite functions in cement as an enabling agent; each bentonite addition equal to 1 per cent of the weight of dry cement makes possible the further addition of 4.5 per cent water.' Thus, 10 per cent bentonite in Class A cement, normally slurried neat with 46 per cent water, enables the slurry to contain another 45 per cent before settling. Water is one of the lightest and cheapest cement extenders; it reduces density and cost. Bentonite cements produce uniform slurries having low susceptibility to solids separation. After set, they offer low resistance to perforation.

By R. J. Stokes

This paper compares the room-temperature mechanical behavior of magnesium oxide crystals containing 'fresh' and 'grown in' sources. 'Fresh' dislocation sources introduced by cleavage or mechanical contact move and multiply to generate slip bands at 3000 psi. Macroscopically the crystals yield smoothly at 6000 psi and can be quite ductile. When 'fresh' sources are eliminated by chemical polishing the crystals have to rely on 'grown in' sources to initiate slip. They then deform elastically up to extremely high stresses (-30 to 50,000 psi) yielding with a sharp stress drop down to the level at which Ifresh' sources operate. Grown in' sources are considered to be associated with impurity wecipitate particles or inclusions. Annealing crystals at 2000°C dissolves these particles thereby eliminating sources for slip. The crystals then become consistently stronger (> 70,000 psi) approaching within 1/10 of the theoretical strength. Dislocations of the grown-in network do not move under stress to nucleate slip. It is proposed that they are locked electrostatically. DISLOCATIONS were originally conceived to resolve the large discrepency between the theoretical and real strength of solids. The idea that slip propagates by the movement of dislocations is now well confirmed both by electron transmission and etch pit studies. But this by itself is not sufficient to explain the low yield strength of crystals for there is still the need to understand where slip dislocations originally come from. Theoretical estimates place the stress to generate dislocations homogeneously in the lattice at approximately 1/30 of the shear modulus,' a value 104 to 105 times greater than the stress at which the very first manifestations of plastic deformation have been observed. Only an special cases can the theoretical strength be approached; in crystals of high perfection such as whiskers2 where dislocation sources do not preexist and in covalent crystals where the dislocations present at room temperature are almost completely immobilized by the bond character of the solid.3,4 For the most part it is necessary to assume that the yield strength of ionic and metallic solids corresponds to the motivation and multiplication of dislocation sources present beforehand. The question as to their origin appeared to be answered by the suggestion of Frank and Read5 that dislocations forming part of the grown-in structure could operate as a mill for the large scale production of dislocations. The Frank-Read mechanism is still widely accepted as the source of dislocations but a number of observations have been reported which are in serious disagreement with it. One of the most intriguing of these is that under normal testing conditions dislocations of the grown-in network appear to play no role in the plastic deformation of rock salt structure ionic solids. This was first reported in the etch pit studies on lithium fluoride by Gilman and Johnston6 and is true also for magnesium oxide. To explain the comparatively low yield stress of lithium fluoride it was proposed by a number of authors7,9 that small unresolved prismatic loops formed by vacancy condensation were acting either directly or indirectly as the dislocation sources. This proposal led Gilman10 to perform a series of detailed and careful experiments on lithium fluoride to try to identify the sources responsible for the initiation of slip. He concluded that prismatic loops played no general role and that other sources were more important. Dislocation sources in ionic crystals can be divided into two general categories. First, there

Jan 1, 1962

By Fred H. Poettmann, J. K. Welchon, A. F. Bertuzzi

A series of gas-lift tests was made which verified conclusions reached from previous studies and which showed that gas-lift performance could be calculated if reasonably accurate data on the producing characteristics of the well are available.' The test installation is described. Its essential features consisted of a rate-of-flow controller to regulate the input gas and an auxiliary string of small diameter tubing to conduct the input gas to the point of injection in the eductor tubing. In general, it was shown that for continuous gas-lift operation, injection should be as deep as possible consistent with available gas pressure and rate of production desired. Calculated curves are presented which completely characterize the gas-lift performance of the well tested. INTRODUCTION A correlation based on field data from a large number of flowing and gas-lift wells, covering a wide range of oper- ating conditions, was developed which permitted the logical design and prediction of the performance of continuous gaslift installations.' The procedure made it possible to calculate the depth, pressure, rate at which to inject gas, horsepower requirements, and the effect of production rate and tubing size on these quantities. As a result of these calculations certain significant facts were brought to light or re-emphasized. The presence of efficient ranges of operation and an optimum injection depth for a given rate of production were shown to exist as well as the fact that the lower the tubing pressure the less the horsepower requirements to lift the reservoir fluids. The fact that the gas lift performance can be predicted by calculation does not mean that any given installation will perform over the entire range predicted. Many of the conventional continuous gas-lift installations will not permit operation over the entire range predicted by calculation (particularly in the efficient range of operation) because of the performance characteristics of the installation. Consequently, field tests were initiated for the purpose of investigating and arriving at a simple continuous gas-lift installation which would operate under all conditions predicted by calculation. The first series of tests involved the use of mechanically operated valves. These valves were slip-joint type valves which are opened and closed by lowering or raising the tubing at the surface by means of a hydraulic jack. These valves were chosen because it was hoped that they could be opened or closed at will and did not depend on the gas pressure in the annulus or the pressure of the fluid in the tubing for their operation. Unfortunately, the valves did not operate satisfactorily and it was imossible to open or close each valve at will. Some limited data were obtained, however, which verified the predicted benefits resulting from the use of lower tubing pressures. In the next series of tests the valves were removed and the gas was injected from the annulus through a 14/64-in. orifice equipped with a reverse check valve. A packer was set below the valve to seal off the space between the 2-in. tubing and 5-in. casing. The injection point was located at 3,810 ft. This arrangement provided satisfactory mechanical operation. However, it was impossible to obtain low rates of liquid production at low tubing pressures as predicted by calculation. A minimum gas injection rate existed below which steady flow was impossible. Liquid pro-

Jan 1, 1953

By Paul D. Conatore

INTRODUCTION There are important reasons for a discussion of tungsten resources, reserves, and production in the Circum-Pacific area. First, the world's chief tungsten deposits, as well as most of the world's tungsten reserves and production, occur in this region. It is well known that the world's largest tungsten reserves are located in southeastern China and that for many years, the largest individual mine in the world was there. Although China still has the world's greatest tungsten production, the very high-grade scheelite mine of Canada Tungsten Mining Corporation in the Northwest Territories is the largest producer of tungsten today. There is certainly a great quantity of tungsten in Asia, but the strategic importance of this fact is now offset by the wide distribution of mines and production facilities throughout the world, especially in other parts of the Circum-Pacific area such as Australia, Canada, and the United States. In addition, much of the Circum-Pacific area is comprised of Mesozoic-Cenozoic orogenic belts. These global tectonic units are regarded as very favorable for additional tungsten deposits, particularly scheelite-bearing tactites, and consequently, prospecting and exploration will most likely be concentrated in the Circum-Pacific area. Second, tungsten must be regarded as one of the, most important metals of modern industry because of its very special properties. It has the highest melting point, the highest tensile strength at elevated temperatures, and the smallest compressibility of any metal. The metal also possesses a very high density, excellent corrosion resistance, good thermal and electrical conductivity, and a low coefficient of expansion. As a result, tungsten has found increasing importance in a wide range of industries. From the filament in an electric lamp, to cutting tools and drilling bits, to the exotic radiation shields that protect supersonic aircraft and spacecraft, tungsten plays an indispensable role in our daily lives. The primary objective of this paper is to present an overview of important facets of known and suspected tungsten in the Circum-Pacific area. Resources, reserves, current production, planned capacity expansions, and new operations, as well as an assessment of the probability for development of deposits in the Circum-Pacific area, are discussed. RESOURCES The average crustal abundance of tungsten has been estimated at 0.0015 kilograms per tonne. A comparison of the abundance of various metals in crustal rocks to that of tungsten is presented in Table 1, which shows that tungsten abundance is similar to that of its commonly associated metals, tin and molybdenum. Table 1. AVERAGE CRUSTAL ABUNDANCE OF VARIOUS METALS (Grams per Tonne) [ ] With careful thought, it can be realized that tungsten ore deposits result from the concentration of the metal, through normal geologic processes, to levels substantially greater than its average crustal abundance. The minimum technologically and economically workable tungsten concentration, or cutoff grade, is a function of (1) deposit tonnage, (2) mining and milling methods, (3) production tonnage, (4) capital and operating costs, (5) tungsten market conditions, and (6) value of associated recoverable metals. The tungsten cutoff grade that is currently exploitable at a profit varies from 0.09% W03 to 1.55% W03, reflecting concentration factors from 470 to 8200, as shown in Table 2. Table 2. CURRENT TUNGSTEN CUTOFF GRADES [ ]

Jan 1, 1982

By M. Kaufman, D. Rosenthal

IT would be of great importance to our understanding of the phenomena of fracture in metals if a unique relationship could be established between stress and some easily measurable parameter of deformation up to the fracture. It is known that no such relationshir, has been found when the parameter was the mechanically measured strain,' the major part of which is plastic. The present investigation was initiated to determine, among other things, if the X-ray or lattice strain" might be a • For the definition of lattice strain see ref. 2. more suitable parameter. To this end, annealed stress free*' specimens of 61s aluminum alloy were ** Freedom of stress in this particular case means absence of those stresses which can be checked by the technique employed. tested at room temperature and liquid nitrogen temperature (—195OC), by first maintaining the same temperature from the beginning until the end of the test, and then with crossovers from one temperature to the other. Three major factors had to be taken into consideration in designing the specimens and testing equipment. The test setup must allow X-ray pictures to be taken while the specimen is under load (for as much as 2 hr at a given load). Provision must be made for maintaining the test specimen at the temperature of liquid nitrogen as well as at room temperature. In addition, the specimen must be able to rotate to allow the X,ray beam to take in as large a sample of grains as possible, to maintain centering, and to correct for effects of large grains. The final design of the specimen and equipment is shown in Figs. 1 and 2. The specimen and grips are hollow, enabling liquid nitrogen to be poured in through a funnel-container arrangement while the specimen is rotating. The diameter of the specimens at the 2 in. gage section is 5/16 in. with a 3/16 in. diameter hole through the center. A small pilot valve in the lower grip allows a very small stream of liquid nitrogen to escape, thus assuring circulation of the liquid at all times. A low temperature silicone grease-tissue paper packing is used to seal all joints. The specimen is held in the grips by a pin. Spherical socket joints at top and bottom are used to allow for proper alignment. The grips are connected to the thrust bearings by means of plastic couplings to decrease the heat flow. Rotation is accomplished by means of a motor which drives a plastic gear (integral with the lower coupling) through a semiuniversal joint to allow for deforma- tion of the specimen. The torque applied to the specimen is very small. The maximum stress caused by this torque at the highest loads reached was found to be less than 200 psi, The whole unit was mounted in a 10,000 Ib testing machine. An insulation cage was placed around the specimen to cut down air circulation, and consequent frosting of the specimen, and also to reduce radiation and convection heat losses. A narrow window, covered on both sides with a thin plastic materiai allows the X-ray beam to reach the specimen. Thermocouples placed just outside the pilot hole at the lower grip, in the bottom of the funnel container and near the top of the funnel container permitted checks of the

Jan 1, 1955

By M. J. Spendlove, H. W. St. Clair

An automatic surface-follower mechanism was used to measure the surface temperature and the rate of evaporation of molten zinc while undergoing distillation at low pressure. At pressures of 50 to 100 microns Hg, the rate of evaporation may be 60 to 80 pct of the theoretical maximum corresponding to the measured temperature. The rate decreases rapidly at pressures above 100 microns Hg, to only 7 pct of the theoretical maximum at 2000 microns Hg. Measured temperature gradients at the surface are in agreement with theoretical gradients calculated from the heat of vaporization, rate of evaporation, and thermal conductivity of molten zinc. THIS paper covers a series of careful measurements of the rate of evaporation of molten zinc at low pressures, undertaken as a part of a general investigation on the separation of metals by distillation.' Preliminary results on the rate of evaporation of zinc were described in a previous publication.' The results of the preliminary study are as follows: 1—The observed rates of evaporation of zinc were as high as 0.60 g per sq cm per min, corresponding to 75 pct of the maximum rate as determined by the temperature of the metal. 2—The evaporation rate was decreased from 0.30 g per sq cm per min at a pressure of 25 microns to only 0.09 g per sq cm per min when the pressure was increased to 5 mm. 3—The temperature of the surface during rapid evaporation may be 35" to 100°C less than the main mass of metal. Observed temperature gradients at the surface are consistent with those calculated from the heat of vaporization and the thermal conductivity of liquid zinc. In the preliminary experiments, the rate of evaporation was determined from the loss in weight of the metal in the crucible during the test. This was compared with the weight of the condensate. Obviously, this method was subject to error because of some uncertainty as to the period of evaporation that should correspond to the loss in weight. Furthermore, this method did not permit taking into account probable variations in the rate of evaporation during the test. A more serious shortcoming was that the temperature at the evaporating surface was not known, so the maximum theoretical rate of evaporation could not be calculated accurately. To improve the precision of rate measurements and to allow accurate measurements of the surface temperature, a refined experimental technique was developed whereby the temperature and position of the surface could be measured accurately. This was done by an automatic surface-follower mechanism that gave a continuous record of the surface temperature and the amount of zinc evaporated. These data permitted an instantaneous determination of the actual rate of evaporation and the surface temperature throughout the test. Pure zinc (99.99 pct Zn) was used in all experiments. Description of Distillation Furnace The details of construction of the distillation furnace are shown in Fig. l. The furnace is enclosed in a large quartz tube open at one end. The open end of the quartz tube is sealed by means of a water-cooled head. The entire enclosure is vacuum tight. The connection between the water-cooled head and the quartz tube is sealed by means of a rubber gasket which fits tightly against the smooth end of the tube. The metal is heated by induced current set up in the molten zinc and the walls of the graphite crucible by means of a water-cooled induction coil outside the quartz tube. High frequency current is passed through the induction coil from a 6 kw mer-

Jan 1, 1952

By Charles C. Templeton

Any explanation of the nature of multiphase fluid flow through porous media must ultimately involve a knowledge of the mechanism of such flow through the individual pores of the medium. To provide quantitative information of the latter type, a study was made of gas-liquid and liquid-liquid displacements in single uniform Pyrex capillaries with diameters as small as 4 microns. Quantitative observation of air-liquid displacements with zero contact. angle indicates the adequacy of a model based on Poiseuille's Law and the independence of capillary pressure and interfacial velocity. Consequently, this work discounts previous claims that flow is abnormally retarded in very small capillaries. For the displacement of a very viscous oil by water in a capillary initially filled with water, flow is faster than predicted by the above model. This behavior is probably due to the existence of a thin annular film of water between the oil column and the capi1lary wall as postulated by Yuster. INTRODUCTION The need for experimental observation of the microscopic nature of multiphase fluid flow, to further the understanding of the results of macroscopic flow investigations, has been previously recognized. Chatenever and Calhoun1 in connection with the API Project 47B have extensively studied the flow of fluids through layers of glass or lucite spheres between glass or lucite plates. Lowman2 prepared an interesting film concerning flow in a single capillary, using an apparatus which made a moving interface appear stationary in the field of a microscope. The purpose of the present investigation was to deter- mine what contribution might be made to this field by comprehensive quantitative observation of gas-liquid and liquid-liquid displacements in single capillaries of uniform, very small diameter. The techniques used are similar to those of Lowman but incorporate improvements necessary for quantitative work. Quantitative observations must begin with fluids of simple chemical composition to provide a basis for analyzing the more complex behavior that may be expected with natural reservoir fluids. However, some qualitative observations on systems involving crude oils are presented. Experiments of this sort involve the observation of the velocity of the interface separating two fluids, and have been performed in horizontal or vertical capillaries by several investigators.3,4,5,6,7,8 The most general treatment of their mechanics, by Brittin,9 involves forces due to capillarity, viscous resistance, gravity, an "end-drag" effect, and the rate of change of momentum of the capillary contents. Since the range of pore diameters of interest in petroleum reservoirs is about 0.1 to 100 microns, it was desired to perform these experiments in the smallest capillaries possible, to ascertain whether capillary diameter had any effect on the existing theory based on data from larger capillaries.* It was also important to be able more systematically to vary the direction and rate of displacement than was done by previous investigators. Finally, to concentrate attention on viscous and capillary forces by eliminating gravity as a parameter, this study involves only horizontal capillaries. The work of Eley and Pepper' with a "large" (0.766-mm diameter) horizontal capillary is the previous investigation which is most similar to the present method of quantitative observation. Here capillaries with diameters as small as 4 microns will be studied.

Jan 1, 1955

By L. T. Sanchez, W. T. Rogers

This paper presents the results of a production experiment evaluating the effect of the use of oxygen in the bessemer converter with respect to its relation to blowing time, amount of steel scrap or cold pig iron which can be melted and teeming temperatures of the molten steel. THE simplest and probably the most efficient and economical means for producing steel from molten pig iron is the bessemer converter. This process is essentially a mechanism for bringing oxygen into contact with the molten metal thereby oxidizing the elements silicon, manganese, and carbon. The source of oxygen is that contained in the air and is limited by that amount. In theory, there is an intermediate chemical reaction due to the mass action of iron and air which is represented by the equation: 2Fe + O2- = 2Fe0 The FeO then becomes the oxidizing agent and reacts with the silicon, manganese, and carbon to produce silicon dioxide (SiO,), manganese oxide (MnO), and carbon monoxide (CO), in the order mentioned. The balancing of the various chemical reactions shows that in the ordinary bessemer process more than sufficient oxygen is delivered to satisfy these reactions, which indicates that a further increase in the oxygen content of the air would serve no useful purpose. In spite of this reasoning, however, it will be demonstrated that when melting stelel scrap, commercially pure industrial oxygen introduced into the normal air blast will permit the melting of a larger proportion of steel scrap than is possible with air alone and also will increase the production rate by a substantial reduction in blowing time. It will also be shown that when melting cold pig iron, it is possible to melt up to twice as much pig iron with the use of oxygen as can be melted without added oxygen with a nominal increase in blowing time. At the plant where this study was made, oxygen is purchased from a nearby supplier and piped directly into the plant. It is supplied to the bessemer converter by being introduced directly into the blast line through an automatic control system which may be adjusted by the bessemer operator or "blower." Normally, iron is supplied by five blast furnaces to an open hearth shop containing twelve 165-ton capacity stationary furnaces and a bessemer converting shop having three 30-ton converters. The molten metal from the blast furnaces is allocated to one shop or the other in a manner to best provide for maximum production. At various times, it is desirable to direct the maximum amount of available blast furnace production to the open hearth shop. This has the effect of reducing the production of the bessemer shop. When this condition exists, it is desirable to supplement the reduced iron charge at the bessemer with steel scrap or cold pig iron to the maximum possible extent in order to maintain high total ingot production. This condition becomes aggravated when one of the blast furnaces is taken out of production for any repair job and particularly for extended periods such as when relining is necessary. The purpose of the investigation and experimentation with oxygen was to determine whether or not it would contribute to increased flexibility in the use of the raw materials, molten iron, steel scrap, and cold pig iron. In addition to the effect of oxygen on flexibility of operation, it was also necessary to determine the relation of its use to production rate or "blowing time," final finishing temperature of the steel or "teeming temperature," and steel quality.

Jan 1, 1953

By S. Leber

Pole figures and pole distributions were used for the quantitative detevinination of the preferred orientations in swaged tungsten rods and the effect of subsequent wire drawing on the texture. In the swaged rod, the preferred orientation could best be described as a pseudo (111-112) [110] cylindrical texture. A secondary component was assigned the indices (110) [001]. Further reduction by swaging retained these cylindrical textures. Wire drawing caused lattice rotations about the wire axis, converting the cylindrical texture into a normal fiber texture. The conversion was initiated and proceeded lnost rapidly in the center of the wire. The (110) /001] component was converted into a (110) fiber texture by wire drawing. The effective rotations were about axes contained in the lransverse plane. The preferred orientation associated with tungsten wire usually has been assumed to consist of a (110) fiber texture. This implies rotational randomness around the wire axis. Leber1 has shown that rotation about the wire axis may be restricted resulting in a preferred orientation designated as a cylindrical texture. Specific crystal planes tended to remain aligned parallel to the wire surface. This texture seemed to be the result of the swaging operation used in the intermediate stages of fabrication. Bhandary and cullity2 detected similar textures in swaged iron wires. Peck and Thomas3 suggested that the preferential alignment of crystal planes parallel to the wire surface was the result of tangential flow, characteristic of swaging. Wire drawing, following swaging, twisted the crystals about axes parallel to the wire axis, converting the cylindrical texture into a normal fiber texture.4 In this investigation, quantitative techniques were used to more accurately characterize the cylindrical texture and to study its conversion into a normal fiber texture. PROCEDURE The material investigated was lamp-quality tungsten. Three ingots were rod-rolled and swaged to 112 mils diameter, and were then drawn to 10-mil wire. Samples were obtained after each drawing pass. (110) and (200) pole figures were obtained from samples prepared as shown in Fig. 1. To form the sample shown in Fig. l(a), l-in. lengths of wire were glued side by side to form a l-in. square. The composite was ground and electropolished to form a diametral reference surface. For certain specific tests, samples were prepared as shown in Fig. l(b). This composite was made from 10-mil-thick strips prepared by grinding on parallel longitudinal planes. The polished reference surface in this case was, in essence, the wire surface. The two forms of samples [~igs. l(a) and l(b)] were related by a 90-deg rotation around the wire axis. Because of ease in preparation, most data was obtained from the diametral samples. The X-ray data were obtained using a Siemen's pole-figure goniometer. These data were not corrected for absorption or defocusing effects, since only the angular locations of the intensity maxima were of interest. Regions of the pole figure more than 80 deg from the center were not investigated. Partial monochromatization was achieved by the use of unfiltered copper radiation and a krypton-filled proportional counter. No evidence of spurious white radiation effects5 could be detected. Therefore, more elaborate X-ray techniques were not required. Intensity levels were chosen to show all pertinent details of the orientation distributions. The reference plane for the pole figures was the diametral section. The orthogonal reference directions, shown in Fig. 1, were the wire axis, the radial axis per-

Jan 1, 1965

By D. G. Russell

Two techniques have been developed with which the applicability of pressure build-up analyses can be extended to include pressure data which previously have been considered virtually unusable. One of the interpretation methods makes possible the analysis of pressure build-up performance during the wellbore fill-up or after production period which occurs soon after a well is closed in. The other technique is an extension of a method for analyzing pressure build-up performance during the late-time portion of the pressure build-up which occurs after boundary eflects first begin to alter the shape of a conventional pressure build-up curve. With both of these methods it is possible to obtain estitnates of the kh product, the skin factor and the reservoir pressure. In addition, with the late-time analysis technique it is possible to obtain an estimate of the contributory drainage volume of the well being tested. This means that in some cases a check on reservoir limit test and (or) material-balance calculations can now be obtained from pressure build-ups. Both methods are slightly more time-consuming than conventional pressure build-up analysis methods because trial-and-error plots of pressure data must be made. The late-time method for analysis of pressure build-ups is in principle applicable to the late-time portion of a two-rate flow test or a pressure drawdown test. The interpretation formulas and procedures for these types of tests are also outlined. In these cases, as with pressure build-ups, it is significant that an estimate of the contributory pore volume is also obtained. On the basis of limited experience with the new techniques, it appears that satisfactory estimates of the kh product, skin factor, reservoir pressure and, for late-time analysis, contributory drainage volume can be obtained. INTRODUCTION The analysis of bottom-hole pressure build-up behavior in closed-in wells has been a a subject of interest in petroleum engineering circles for many years. In fact, few other subjects have received as much attention as pressure buildup analysis methods have. The cause for this interest is essentially twofold in nature. First, the pressure behavior of a well can normally be measured with a reasonably high degree of accuracy so that good data for analysis can be obtained. Secondly, over a fairly wide range of operating conditions, valuable information as to the quality of the reservoir rock and completion efficiency of the well can be obtained at a nominal cost. In recent years, numerous papers have been prepared on the effects of various operating conditions and reservoir heterogeneities on pressure buildup behavior. Very little work has been done, however, on extension of pressure build-up analysis methods to those pressure data which are not amenable to analysis by the present methods. The theory upon which the analysis of shut-in bottom-hole pressure build-up data is based is derived from the solution of the radial flow equation for a slightly compressible fluid for constant-rate conditions. It requires that the well be closed in for a sufficient period of time to obtain a clearly defined linear portion on the plot of observed bottom-hole pressure vs log (t + ?t)/ ?t (where At is shut-in time, and t is producing time to the instant of shut-in). From the slope of the plot and other normally obtainable data, the formation permeability, the well damage or skin factor, and the reservoir pressure at infinite shut-in time (if the reservoir were infinite) can be estimated. The successful application of this procedure depends on being able to recognize the straight-line section on the basic pressure build-up plot. The presently used pressure build-up interpretation theory also assumes that a well is closed in at the sand face and that no production into the well occurs after shut-in. In practice, of course, the well is closed in at the surface, and inflow into the well continues until the well fills sufficiently to transmit the effect of closing-in to the formation. This adjustment period is commonly referred to as the "afterproduction" or "fill-up" portion of the pressure build-up. During the period that the well fill-up effect is most pronounced, the basic pressure build-up plot is nonlinear. At later shut-in times after the effects of a drainage boundary have been felt at the well, deviation from the straight-line behavior of the pressure build-up plot also results. In many cases either of these effects or a combination of both can make the straight-line portion on the pressure build-up plot difficult to recognize. Obviously, an extension of pressure build-up analysis methods to include the afterproduction period and the period in which boundary effects are being felt would be desirable and might render valuable pressure data which for years have been considered virtually unusable. The principal reference of note concerning pressure buildup analysis during the afterproduction period is a paper by Gladfelter, Tracy and Wilsey.1 In the approach of these authors it is necessary to measure the rate of influx into the well during the afterproduction period. This is done through sonic measurements or through measurement of tubing-head and casing-head pressures simultaneously with

Jan 1, 1967

PERSONAL (Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Oct. 10 to Nov. 10, 1914: Jintaro Kojima, Ashio, Japan. E. R. Hinckley, Seoul, Korea. J. Homer Stover, Trenton, N. J. S. A. Taylor, Pittsburgh, Pa. Kirby Thomas, New York, N. Y. Lawrence Addicks, Douglas, Ariz. Keijiro Nishio, Tokyo, Japan. Noel Cunningham, Bethlehem, Pa. Alexander K. Hamilton, Chicago, Ill. E. C. Vigeon, London, England. Harold N. Lawrie, Portland, Ore. S. E. Fairchild, Jr., Philadelphia, Pa. C. Spence Thomas, Cardiff, Wales. W. C. Schmidt, Jr., New York, N. Y. Henry Tackmann, New York, N. Y. Kenneth C. Browne, New York, N. Y. Dr. David T. Day has resigned his position with the U. S. Geological Survey and opened an office at 1331 F Street, N. W., Washington, D. C., for practice as a consulting engineer.

Jan 12, 1914

By L. K. Jetter, C. J. McHargue

The use of axis charts for representing the texture of cold-rolled thorium sheet was compared with conventional pole figures. Four texture components were deduced from the axis charts and shown to be consistent with the pole figures. It was shown that consideration of the pole figures alone could lead to an apparent component which is the average of two actually present. It was also shown that the spread about the "ideal" textures and the amount of material associated with each could be readily obtained Fom the axis chart method. BECAUSE of the crystallographic nature of the deformation mechanisms in metals, plastic flow results in the alignment of certain crystallographic directions with the primary flow directions. In the study of the "preferred orientation" thus developed, one wishes to discern the distribution of the crystallographic directions with respect to some reference direction, usually a direction related to the fabrication procedure, such as the rolling direction. The pole-figure method, introduced by ever,' involves the plotting of the distribution of the poles of some family of planes on a stereographic projection which places the reference direction(s) at the north pole and/or in the center. By noting the angles between the reference directions and concentrations of poles on several such pole figures, one can deduce the crystallographic directions which are aligned with the reference directions. If the preferred orientation is relatively simple and well-developed, one to three pole figures may be sufficient for obtaining the desired information; if there are several texture components, more pole figures may be needed. A significant improvement in the method of representing the textures in wires and rods resulted from the introduction of the "inverse pole figure" or axis-distribution chart by Harris.2 Such a chart gives directly the distribution of the reference axis relative to the standard stereographic projection. There has been widespread acceptance of this method for the representation of fiber textures, and methods have been proposed for converting observed diffraction intensities into axis densities.2-6 The suggestion by Mitchell and Rowland3 and Jetter, McHargue, and williams5 that sheet textures could be represented as distributions of rolling, normal, and transverse directions have been criticized on the basis that they offer no significant advantage over a combination of two ordinary pole figures and that it has not been proved that sheet textures can be treated as quasi fiber textures.6 If the purpose of a texture determination is to study some property which is related to the orientation of a particular crystallographic plane or direction, then conventional pole figures certainly are sufficient. For example, the distribution of the slip planes in face-centered cubic metals (the (111) pole figure) serves to indicate the variation in mechanical properties of sheet. On the other hand if the study is directed at an understanding of the factors influencing texture formation, it is desirable to know not only the preferred orientation but the kind and degree of spread from it and the relative amounts of material in each component, if there are more than one. Axis charts give this information as well as the orientation distributions. Consider the procedure for deducing a texture component from a pole figure for the (111) planes

Jan 1, 1961

By C. W. Price, G. A. Wheeler

BERYLLIUM has always been a difficult material to prepare for metallographic examination. Severe surface deformation occurs during mechanical grinding and polishing, and a suitable bright-field etchant has not been developed. Certain electrolytic techniques produce satisfactory polishes, but these techniques have not yielded entirely consistent results. Furthermore, they have not provided satisfactory bright-field etches. The purpose of this paper is to describe an electrolytic polishing technique that can also provide an excellent bright-field etch. In addition to the bright-field etch, other advantages of this technique are excellent reproducibility, rapidity, and ease of polishing and etching. Experimental Technique. Specimen Preparation. Beryllium specimens may be either mounted or unmounted for the use of this technique, and the size of the specimens is not important. Specimens with surface areas up to 4 sq cm have been electrolytically polished and etched successfully with this technique. The most important requirement is to provide a good electrical contact to the specimens, preferably on the back of the specimens. When specimens are mounted, a hole is drilled through the back of the mount so that the specimen can be contacted with a probe. Conventional metallographic grinding techniques are used to prepare the specimens for electrolytic polishing. The specimens are ground on silicon carbide papers. Grinding through the usual series of papers down to the 600-grit paper is recommended to minimize the electropolishing time, although successful electrolytic polishes and etches have been obtained by grinding only through the coarser papers. A continuous flow of water is used during grinding to provide lubrication and to minimize contamination. Mechanical polishing is not required because high rates of material removal are achieved with the electrolytic polishing. Polishing. Most of the results reported in this paper were obtained with a "Disa-Electropol", manufactured by Struers Scientific Instruments of Copenhagen, Denmark. Satisfactory results have also been obtained with the conventional beaker technique of electrolytic polishing, however, the conditions applicable to both the Disa unit and the beaker technique will be described. Stainless-steel cathodes are used in both techniques. In the beaker technique, a flat cathode, with an area at least twice that of the specimen, is used, and the specimen is held parallel to the cathode. The distance between the specimen and the cathode affects the quality of the electropolish. This distance is set at about 7 mm in the Disa unit; the same distance produces the best results in the beaker technique. Specimen-cathode distances greater than about 20 mm produce considerable relief, while distances less than 7 mm cause high current densities that are difficult to control. An electrolyte of 2 pct HC1, 2 pct HNO3, and 2 pct HCIOl in ethylene glycol gives the most satisfactory results for both electrolytic polishing and etching. This electrolyte was developed by altering the composition of a similar electrolyte used for electrolytic lapping1 and adding HClOl to improve the etching characteristics of the electrolyte. Variations of from 0.25 pct to as much as 5 pct of each of the acids do not significantly affect the results, but the greatest amount of control and reproducibility can be obtained with the composition of 2 pct of each acid. Generally, lesser amounts of the acids produce lower polishing and etching rates, while greater amounts of acids cause high current densities that are difficult to control.

Jan 1, 1968

By Noel Jarrett, Allen S. Russell, Bernard M. Starner, Stanley C. Jacobs

A process has been developed to refine high-grade commercial aluminum to 99.99 pct purity. This enzploys precipitating titanium, vanadium, and zirconiu~ as borides. The upgraded liquid is partially crystallized under conditions that prevent massive freezing. The resulting crystals are compacted and washed free of adhernig impure liquid aluminum by melting the top crystals while draining off the liquid. Finally, the bottorn portion of the crystal bed is melted and removed as the pure product. Leakage from the crystallizat~on vessel is prevented by a layer of alumina granules that are not wetted by the aluminum. ALUMINUM of 99.99 pct purity is desired in a variety of applications. These include electrolytic capacitors, catalyst carriers, decorative trim for automobiles, aluminum powder, and high-strength alloys. This market was for many years filled by refining commercial-purity aluminum in a three-liquid-layer electrolytic cell of the type originally proposed by Hoopes. To meet the expanding need for lower-cost high-purity aluminum, a refining process based on chemical precipitation and fractional crystallization was developed. The availability of this super-purity metal was announced in November 1961, and three patents1-3 relating to the process were issued in 1965. An alternate process, comprising continuous fractional crystallization of a portion of a liquid-aluminum feed stream under conditions of strong agitation at the surface of the growing crystals, was published by Dewey4 in 1965. Earlier proposals by Larsen 5 and by Regner6 also emphasized the advantage of rapid agitation of the melt in the region of the crystallization zone. johnson 7 more recently proposed extracting purified aluminum from an alloy by mixing crystals of pure aluminum into the molten alloy, allowing them to grow, and removing the pure aluminum as by casting. Aamot's 8 recent patent describes a freeze refining process that involves controlled partial freezing against cooled moving retort walls. The Alcoa process to produce high-purity aluminum is schematically described in Fig. 1. Relatively pure aluminum is treated with boron in a furnace (a) to precipitate high melting point impurities, the supernatant liquid is transferred to a crystallization vessel (b), the liquid is partially crystallized with mechanized "tamping" (c), the remaining impure liquid is tapped out and the crystal bed partially and directionally re-melted to wash the underlying crystals (d), and the balance of the crystals is melted and withdrawn as high-purity aluminum (e). PRINCIPLES OF FRACTIONAL CRYSTALLIZATION Commonly encountered impurity elements form two types of systems with aluminum. Titanium, vanadium, and some other transition elements in periodic groups IV, V, and VI are the high melting point impurities. Initial solidification of aluminum containing small percentages of these elements will produce solid markedly enriched in them at temperatures slightly above the freezing point of high-purity aluminum. Most other elements, such as silicon and iron, produce eutectic type reactions with aluminum. In this case the first solid formed on initial solidification at temperatures slightly below the freezing point for high-purity aluminum is markedly depleted while the remaining liquid is enriched in these elements. The equilibrium change in composition during solidification of aluminum contaminated with silicon, iron, or titanium is illustrated in Fig. 2. Here, for clarity, the temperature scale is expanded beyond the

Jan 1, 1968

By W. L. Falke, A. A. Cochran

A basic problem in connection with manganese is to find economical ways to utilize domestic resources. As a part of its program to conserve domestic mineral resources and to reduce dependence of foreign sources, the Bureau of Mines had conducted extensive research to broaden manganese technology and to find economical, technically-feasible processes for recovering manganese from these low-grade resources. This paper analyzes some of the major difficulties which have been encountered in previously proposed processes for treating low-grade manganese ores and discusses a process which may circumvent many of these difficulties. Vast deposits of low-grade manganese ore exist in the U.S., yet domestic production is insignificant compared to the more than 2 million tons of ore imported yearly into this country.' A basic problem in connection with manganese is to find economical ways to utilize domestic resources.2 As a part of its program to conserve domestic mineral resources and to reduce dependence on foreign sources, the Bureau of Mines has conducted extensive research to broaden manganese technology and to find economical, technically feasible processes for recovering manganese from these low-grade resources. Although a great many processes have been proposed for treating domestic manganese resources, a failing of many of them is that too many steps are involved for economical operation.' Some of the major processes that have been proposed were reviewed by Norman and Kirby.3,4 Chlorination processes have become increasingly useful as a means of recovering valuable metals from raw materials, because the relative cost of chlorine (Cl2) and hydrogen chloride (HC1) has decreased through the years, and because the corrosion resistance of materials of construction has been improved. The objective of these processes is to form metal chlorides that are more volatile or water-soluble than are the corresponding oxides or sulfides; these compounds then can be separated from the gangue or other minerals by volatilization or leaching. Several chlorination processes for the recovery of manganese have been investigated by the Bureau of Mines5-8 and others; the major chlorination processes were reviewed in 1963, and their main features were compared.4 In all these processes, the simultaneous leaching or volatilization of iron chlorides with manganese chloride (MnCl2) is a problem, and the more iron that is present, generally the greater the problem. The leaching step is not highly selective, and the product of this step is, at best, suitable only for the production of ferromanganese or for further processing to remove iron. The product of the volatilization step is, in all cases, a mixture of iron and manganese chlorides that contains too much iron even for ferromanganese production, and must undergo additional processing steps for iron removal. THERMODYNAMIC CONSIDERATIONS The literature indicates that the desired chlorination reactions will proceed at practical rates at temperatures near 1200°K (927°C). Free energy changes at 1200°K for the critical steps of the reduction and chlorination reactions9-11 follow: Most of the research on chlorination processes for manganese recovery has been done with HC1 rather than with C12, for the following three main reasons: 1) Recycling of the chlorinating agent, which is economically vital, appeared to be easier for HC1

Jan 1, 1968

By G. S. Hume

During the war years the drilling activity in Canada has been steadily increasing and still further increase is expected in 1945. The production of oil, which in the past has come largely from the Turner Valley field in Alberta, shows a decline since 1942, the peak year. New discoveries made in 1944, however, give promise of replacing the decrease from Turner Valley where the crude-oil production in 1944 was nearly 1,800,000 bbl. less than in 1942, but with an increase of 145,000 bbl. in natural gasoline, a product of great value to the war effort. A very considerable part of the decline in Alberta has been offset by new production of more than a million barrels in 1944 from the Norman Wells field, in the Mackenzie River area of the Northwest Territories. It should not be forgotten, however, that this is largely due to the Canol development, a war project, the future of which is dependent on many factors not connected with an ordinary commercial operation. The year 1944 has been the best in new discoveries in Alberta for all time. The discovery of a new deep field at Jumping-pound, 20 miles west of Calgary, with the hopc of a type of product similar to that of Turner Valley is the culmination of many years of effort to interpret the subsurface structures in relation to the complicated surface foothills faulting and folding. In this case the subsurface structure on the Paleozoic limestone was inferred from geological investigations but precisely defined by seismograph. In addition to Jumpingpound the discovery of oil of 34.5 gravity at a depth of less than 5000 ft, in the Devonian of the Plains at Princess, 125 miles east of Calgary, is of great significance since this is the first substantial production from the Devonian in Alberta, although previously some oil had been obtained at two places from the Devonian in the foothills. The effect of this discovery is already apparent in the number of wells now drilling to the Devonian in the southern Plains. In southern Alberta a new producing area has been found in a Lower Cretaceous sand at Barnwell, a few miles west of Taber. Also, at Conrad, 20 miles southeast of Taber, an important new discovery has been made at a depth of about 3000 ft. in a sand in Jurassic shales, in a strali-graphic trap on the northeast flank of the Sweetgrass arch. In northeast Central Alberta an important extension has been found in the Lloydminster area, where only a few wells have so far been drilled. A new well 3 1/2 miles south of the previous producers found a coarser sand at the productive horizon and as a result will have an increased daily yield. At Blackfoot, 9 miles west of Lloydrninster, a new producing area in the Lower Cretaceous may have been discovered at a depth of 2004 ft. At the end of 1944 the well was being tested. Forty-four unsuccessful wildcat wells were drilled in Alberta in 1944. The decline of Turner Valley, the major producing field, was anticipated at the beginning of the war and in an effort to offset this and encourage new development the Dominion Government put into force tax concessions and other measures that,

Jan 1, 1945

THE committee in charge of arrangements for the meeting of the Institute in September has com-pleted its program. The headquarters of the meeting will be at the Palace Hotel, San Francisco, and the registration committee will be at the hotel all day on Sunday, Sept. 24, and from 8 a.m. until noon on Monday. On Sunday afternoon, automobiles will be available for sightseeing trips around the city. Monday will be devoted to technical sessions. In the morning, there will be sessions on Mining and on Iron and Steel; in the afternoon, sessions on Mining and Milling. At these sessions, in addition to the papers mentioned in the tentative list printed in August, there will be presented three papers on the geology, mining and milling of the Comstock lode; one on the Aztec mine, Baldy, N. M.; one on the Colombian oil fields; and one on charcoal precipitation of cyanide solutions. The luncheon on that day will be Dutch Treat, for men only, at the Engineers Club. On Monday evening, there will be an informal buffet supper at the home of F. W. Bradley. On Tuesday morning, a party of 50 men will leave for Hetch Hetchy. During the four days of the trip, the party will see the Priest tunnel and earth dam under construction by steam-shovel and hydraulic-fill methods, the Big Creek shaft and tunnel, early intake power plant and tunnels and the Hetch Hetchy dam under construction. For those who remain in San Francisco, Tuesday will be "San Francisco Day." There will be motor trips to the Presidio, Cliff House, Golden Gate Park, and other points of interest, and shopping trips to Chinatown. On Wednesday, "University of California Day," the party will be guided through the university by members of the Mining Association, the affiliated stu-dent society, and will see the Greak Theatre and not-able buildings. Thursday will be "Leland Standford, Jr. University Day." Automobiles will leave the Palace Hotel at 10 a.m., and will return from the university at 4.30 p.m. Friday has been reserved for trips to the Selby Smelter, to Mt. Tamalpais, or to other points of interest. Arrangements will be made to visit the mines or gold dredges in California, if members desire to do so, but such trips must of necessity be considered special trips and arrangements will have to be made to suit the convenience of the individual or party. The Golf Committee will make arrangements for those who wish to play golf.

Jan 9, 1922

By Charles W. Chesterman

Perlite is a glassy volcanic rock which will, upon rapid controlled heating, expand or "pop" into a frothy material of low bulk density, valued as a lightweight aggregate. The term perlite also is applied to the expanded product. The chemical composition of perlite ranges from that of rhyolite to that of andesite; the water content ranges from 2 to 5%. Most perlite is pale gray, but some is black, brown, or even green. Inclusions in perlite are common and include phenocrysts of quartz, feldspar, biotite, and hornblende, and miscellaneous rock fragments. Occurrences of perlite are restricted to areas of Tertiary and Quaternary volcanic rocks. Perlite occurs as flows associated with thick accumulations of pyroclastic debris and other flow rocks, as dikes, sills, domes, and as selvages of intrusive bodies of volcanic rock. Individual flows of perlite range in thickness from a few feet to as much as 100 ft and commonly cover several square miles. Dikes and sills of perlite generally are small, but domes generally are substantial in size and may be as much as several miles in diameter. Most perlite deposits are large enough and topographically situated so as to lend themselves to low-cost open pit mining methods. Conventional equipment is employed in the mining of perlite. Although milling procedures may appear to be simple, care is exercised in order to produce a carefully sized product and to minimize the production of excessive quantities of fine materials, which have limited use and are considered as waste. Perlite is processed, or "popped," in one of two basic types of furnaces: horizontal rotary or vertical stationary. Both types of furnaces include product collection and dust control systems. Many commercial deposits of perlite are known to occur throughout the world, and although no exact estimate of reserves is available, there appears to be an adequate supply to meet current and future worldwide requirements. End Uses The uses of expanded perlite are many and varied and are based primarily upon its physical and chemical properties. Because of its (1) low bulk density, which generally ranges between 2 and 20 lb per cu ft; (2) low thermal conductivity "K" factor (Btu per hr per sq ft per OF per in, of thickness), which ranges between 0.267 for loosely packed perlite (bulk density of 4.48 lb per cu ft) to 1.25 for perlite gypsum plaster; (3) high resistance to fire; and (4) low sound transmission, expanded perlite is used to a great advantage as aggregate and insulating material in the construction industry. Early uses of perlite were related exclusively to the construction industry, which now consumes about 60% of the domestic production. The primary use of perlite now is as aggregate in insulation boards. Other uses of perlite in 1971 were as aggregate for plaster, horticultural aggregate, low-temperature insulation (cryogenics), and concrete. Because of its low thermal conductivity ("K" factor), high adsorption of sound, low bulk density, and fire resistance, perlite aggregate plasters hold many advantages over conventional plaster. Perlite aggregate plaster lends itself to machine applications, dries quickly, and has relatively high elasticity which reduces cracking after drying. These same features make perlite useful as aggregate in portland cement concrete and asphalt concrete for construction wherever weight reduction, insulation, and acoustics are of prime importance. Perlite-portland cement concrete offers up to 20 times more thermal insulation than conventional concrete, and because of this it finds wide application in roof decks and floor fill in multistory buildings, in

Jan 1, 1975

By A. Rosenzweig, M. M. Karnowsky

The generalized binary diagram of the Au-Sn-Pb system is presented. The chief characteristic is the pseudobinary between lead and AuSn. On the high-gold side of the pseudobinary, four reaction isotherms were found at 363°, 274°, 225°, and 204°C. On the low-gold side of the pseudobinary, three reaction isotherms at 277°, 205°, and 176°C were found. A vertical section from the eutectic solder composition to gold was developed from the isothermal sections generated. METALLURGICAL problems arising from the intentional or accidental formation of Au-Sn-Pb alloys in soldering applications have indicated a need for information on the phase equilibria in this ternary system. The literature indicates that a complete diagram presenting this information has not been prepared. Even the recent excellent work by prince' entitled "The Au-Pb-Sn Ternary System" actually extends only to the AuSn or 50 at. pct Au range. There are more events in the 50 to 100 at. pct Au than in the less than 50 at. pct range. This article by Prince furnished much guidance in preparing this report. Initial efforts with the isopleth from the eutectic solder composition 61.9 wt pct Sn-38.1 wt pct Pb and 0 to 90 wt pct Au indicated that extensions of the work to the whole of the diagram (even if in less detail) were necessary to understand this system. In undertaking the construction of such a diagram, this study used differential thermal analyses (DTA) and metallography with verification and identification of phases by electron microprobe analyses. EXPERIMENTAL PROCEDURE The procedure began with the development of a cell which would be unreactive with lead, tin, and gold, retain its strength to 1100°C, exclude oxygen, and also furnish a suitable well for insertion and protection of a thermocouple to monitor temperature changes in the material. Such a cell would make it possible to reuse the sample should a repetition of determination be desired. Fig. 1 is a photograph of two such quartz cells as finally developed. The specimens have been run many times. The cell is made up of an inner sample bucket and an outer capsule with a thermocouple well which the sample surrounds. The DTA unit was an assembly devised from available instrumentation. The sample holder was a 3-in.-long cylinder of nickel, 2 1/2 in. in diam, fitted securely in a vertical tube furnace. Two holes 7/8 in. in diam were symmetrically located to receive the quartz cells. A dummy cell with nickel powder was used as the reference. The absolute temperature was recorded with a Pt/Pt 10-pct Rh thermocouple with an automatic Kaye ice bath compensator. (Calibration indicated the compensator to be accurate to better than ±0.5° over the 100° to 1000°C range.) The absolute temperature was measured in the sample and recorded on an L&N mul-tirange recorder with a full-scale display of 1 mv and automatic ranging of 99 mv. The differential signal between the sample temperature and the reference temperature was amplified with an L&N microvolt amplifier and recorded on an L&N Speedomax G recorder. Since two charts were obtained, the chart speeds were equalized and each event was noted on the differential chart, and the temperature at that time was obtained from the temperature record.

Jan 1, 1969

President-Mrs Robert D Coombs, 375 Paramus Road, Paramus, N J First Vice-President-Mrs Howard R Norsworthy, 333 East 53 Street, New York 22, N Y Second Vice-President-Mrs Arthur Notman, Circle Road, Dongan Hills, Staten Island 4, New York Third Viee-President-Mrs David Eugene Park, 30 Sutton Place, New York 22, N Y Fourth Vice-President-Mrs Cony T Brown, 211 East Abeyta Avenue, Socorro, New Mexico Fifth Viee-President-Mrs J A Carpenter, 245 University Terrace, Reno, Nevada Recording Secretary-Mrs W McG Peirce, 7 Lexington Avenue, New York 10, N Y Asst Recording Secretary-Mrs Arnold H Miller, 601 West 115 Street, New York 25, New York Corresponding Secretary-Mrs Theodore Nagel, 76 Remsen Street, Brooklyn 1, New York Treasurer-Mrs Robert W Rowen, 116 East 68 Street, New York 21, N Y Assistant Treasurer-Mrs Samuel H Dolbear, 11 Broadway, New York 4, N Y Assistant Treasurer-Mrs H A Kursell, 12 Murray Hill Road, Scarsdale, New York

Jan 1, 1955