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CONTENTS PAGE. WHITE, DAVID.-Environmental Conditions of Deposition of Coal. Discussed by E. C. Jeffrey, George H. Ashley, Reinhardt Thiessen, S. W. Parr, David B. Reger, Wilbur A. Nelson, James F. Kemp, E. S. Moore, Homer G. Turner, David White, A. C. Noé, W. A. I. M. van Waterschoot van der Gracht 2 THIESSEN, REINHARDT.-The Constitution of Coal. Discussed by Edward C. Jeffrey, Reinhardt Thiessen, Ralph H. Sweetser, David White 12 TURNER, HOMER G.-Microscopical Structure of Anthracite. Discussed by E. S. Moore, Edward C. Jeffrey, Reinhardt Thiessen, H. J. Rose, James F. Kemp, David White, Clarence A. Seyler, A. C. Noé 14 JEFFREY, EDWARD C.-Coal in Relation to Coke. Discussed by H. J. Rose, David White, E. S. Sinkinson, S. W. Parr, James F. Kemp, Edward C. Jeffrey, Reinhardt Thiessen, Chas. R. Fettke 17 FRANCIS, W., and WHEELER, R. V.-The Resolution of Coal by Oxidation. Discussed by Edward C. Jeffrey, S. W. Parr, E. S. Sinkinson, Reinhardt Thiessen, David White 23 TIDESWELL, F. V., and WHEELER, R. V.-The Constitution of Coal. Discussed by David White, A. C. Fieldner 24 JOLLY, J., and WHEELER, R. V.-Organic Sulfur Compounds in Coal. Discussed by S. W. Parr 25 SINNATT, F. S.-Selective Combustion in Coal. Discussed by J. D. Davis, A. C. Fieldner, Geo. S. Rice, W. M. Grant, H. J. Rose, S. W. Parr, David White 25 COBB, JOHN W.-Nitrogenous Constituents of Coal. Discussed by S. W. Parr, H. J. Rose, Reinhardt Thiessen 28 PARR, S. W., and HOBART, F. B.-Coal and Oxygen. Discussed by J. D. Davis, W. T. Thorm, Jr., S. W. Parr, H. J. Rose, A. C. Fieldner, F. F. Jorgensen, David White, W. M. Grant 30 FIELDNER, A. C., and DAVIS, J. D.-Modern Views of Chemistry of Coals of Different Ranks as Conglomerates. Discussed by S. W. Parr, David White, Reinhardt Thiessen, A. C. Fieldner, Clarence A. Seyler 32 EBY, J. BRIAN.-Contact Metamorphism of Some Colorado Coals. Discussed by Geo. C. McFarlane, W. T. Thom, Jr 35 WHITE, DAVID.-Progressive Regional Carbonization of Coals. Discussed by A. C. Fieldner, Homer G. Turner, W. A. J. M. van Waterschoot van der Gracht, A. C. Noé 37 THOM, W. T., JR.-Moisture as a Component of the Volatile Matter of Coal. Discussed by A. C. Fieldner, S. W. Parr, Clarence A. Seyler, W. T. Thom, Jr., R. D. Hall 39

Jan 7, 1925

By Arthur Notman

DURING the past fifteen years there has been a great change in the methods of treating employ-ment and discharge throughout industry. Perhaps nowhere has this change come more abruptly than in the metal mining districts of the West. In 1909, when I went to work for the Phelps Dodge Corporation in Bisbee, their operations were roughly arranged accord-ing to shafts in seven divisions, each employing from 100 to 250 men underground, and the mechanical department employing some 250 men, mostly on the surface. The underground divisions were each in charge of a foreman who had under him a night foreman and from two to four shift bosses on' each of two shifts. These foremen reported to the underground superinten-dent and he in turn to the superintendent of the mine department. The mechanical department was in charge of the master mechanic who reported to the superintendent of the mine department. RUSTLING A JOB IN THE OLD DAYS It was customary for men seeking employment to "rustle" the division foreman at the shaft during the lunch hour or at the close of the day shift and the master mechanic at the shops. There was no real attempt at interviewing the applicants for underground work. They simply filed in and out of the foremen's office-50 to 150 strong-in ten or fifteen minutes. If the foreman needed men, and he generally did; to replace those that he and the shift bosses had removed during the morning, he picked out those he knew or strangers who took his' fancy. The former in many cases were chosen for negative reasons rather than positive. In selecting the latter, the foreman felt that if they failed to show ability promptly, he could replace them the next day, and often did so. Even if these foremen had been skilful and well trained in the art of selecting men, it would have been impossible under the pressure of other duties to exercise that skill and experience in so doing. The conditions in the mechani-cal department were little better. About all that can be said in favor of such a method was that with a sur-plus of labor it "got by." The labor shortage brought about by the war disclosed its fundamental weakness.

Jan 6, 1923

By Albert Sauveur

As director of the Division of Metallurgy of the Technical Section of the Air Service, American Expeditionary Forces, from August, 1917, to January, 1919, I devoted much time to the study of the steels best suited to the construction of aircraft. It became apparent at a very early stage of my investigation that the practice of builders varied greatly in regard to the number of different steels to be used, to the kinds of steels, and to their treatment. Some manufacturers employed as many as fifteen steels while the builder of one of the newest motors, favorably passed upon in the United States, assured me that two or, at the most, three kinds of steel were all he needed to produce satisfactory results. In the matter of treatment, the manufacturers were also greatly at variance. Some treated their steel with considerable refinement while others paid but scant attention to this feature. Some manufacturers case-hardened many parts, while others used the case-hardening process sparingly, if at all. Nickel-chromium steels were used at some works for case-hardening while at other plants this treatment was applied exclusively to carbon steels. Air-hardening nickel-chromium steel was used extensively by some and not at all by others. Considerable variance existed likewise in regard to the steels used for admission and exhaust valves. The conclusion was obvious, that no two manufacturers of airplane motors held like opinions as to the steels to be used or as to the treatment they should receive. Was it to be inferred from this that the many committees and associations that had been created, in part at least, for the standardization of aircraft steels had failed to make proper recommendations or that the manufacturers had ignored their recommendations ? Confining our inquiry to the committees and associations that had dealt with this question in England, France, and the United States, it was found that in Great Britain the British Engineering Standards Committee, now the British Engineering Standards Association, had devoted much time to the problem of satisfactory standards for aircraft steels. In April, 1918, this Association presented a set of specifications described as "British Standard Specifications for Aircraft Steels for Government Purchases in the United States of America." They included twenty-one different steels and, as the title indicates, were drawn for the

Jan 1, 1920

By D. E. Furman

The thermal coefficients of linear expansion for several stainless steels have been determined over the temperature range from —300° to 1000°F. The steels studied include types 301, 304, 316, 347, 310 and 330. This wide selection of compositions allows an insight into the effects of austenite stability and alloy content on the expansion characteristics. THE recent increased use of materials in low temperature applications has created a field for which the properties of austenitic iron, chromium, nickel alloys are particularly suited. Tensile and impact values of stainless steels at subzero temperatures have been made available in the technical literature but, as yet, little information has been published with respect to expansion characteristics. In order to supply this need, a study was made of several of the more common compositions. Those selected were types 301, 304, 316, 347, 310 and 330 stainless steel. Both the mean and instantaneous coefficients of linear expansion were determined over the temperature range from —300°F to 1000°F. Procedure The materials used were commercial grades with the exception of type 301 which was made in a 10# high frequency furnace. The compositions are listed in table I. All steels were given an anneal at 1950°F for 30 min and water quenched prior to machining the expansion specimens. Expansion readings were taken on specimens 0.250 in. in diam by 4.000 in. long with a fused quartz tube expansion apparatus similar to that described by Hidnert and Souder.1 Temperature measurements were made with a chromel-alurnel thermocouple calibrated for use at subzero temperatures. A bath of propane was used for temperatures from —300° to —100°F and one of alcohol from —100°F to room temperature. These baths were contained in large mouthed Dewar flasks and cooled to the desired temperature levels by passing liquid nitrogen through glass cooling coils placed in the flasks. The baths were stirred constantly for temperature equalization and were heated by immersing metal rods which were replaced frequently enough to give a heating rate of approximately 150°F per hr. A resistance wound furnace was used for heating from room temperature to 1000°F and throughout this range rates of about 450°F per hr were maintained. The furnace was designed so that the temperature gradient over the specimen was within 5°F. In most instances, the expansion readings were taken during heating from —300° to +300°F at

Jan 1, 1951

By Shiou-Chuan Sun

THIS paper presents the design and operation of a frothmeter capable of measuring the frothing characteristics of pine oils and other frothing reagents. The experimental data show that the froth-ability of pine oil is governed by: 1—rate of aeration, 2—time of aeration, 3—height of liquid column, 4—chemical composition of pine oil, 5—pH value of solution, 6—temperature of solution, and 7—concentration of pine oil in solution. The effect of mineral particles on the behavior of froth also was studied, and the results can be found in a separate paper.' The results also show that the relative froth-abilities of pine oils in the frothmeter generally correlate with those in actual flotation, provided that other factors are kept constant. In addition to pine oils, the other well-established flotation frothers were tested, and the results are included. In this paper, compressed air frothing is the frothing process performed by means of purified compressed air, whereas sucked air frothing is the frothing process accomplished by purified air sucked into the glass cylinder by a vacuum system. The term vacuum frothing denotes that froth was formed by degassing of the air-saturated liquid under a closed vacuum system. Apparatus The frothmeter, shown in Fig. 1, is capable of re-producibly measuring the volume and persistence of froth as well as the volume of air bubbles entrapped in the liquid and is capable of being used for compressed air frothing, sucked air frothing, and vacuum frothing. Fig. la shows that for compressed air frothing, the apparatus consists of an airflow regulating system, 1-3; a purifying and drying system, 4-8; a standardized flowmeter to measure the rate of airflow from zero to 500 cc per sec, 9; and a graduated glass cylinder, 13; equipped with an air regulating stopcock, 10; an air chamber, 11; and a fritted glass disk to produce froth, 12. The fritted glass disk, 5 cm in diam and 0.3 cm thick, has an average pore diameter of 85 to 145 microns. The pyrex glass cylinder has a uniform ID of 5.588 cm and an effective height of 63 cm. The inside cross-sectional area of the glass cylinder was calculated to be 24.53 sq cm, or 3.8 sq in. For sucked air frothing, Fig. lb shows that the apparatus for compressed air frothing is used again, with the following modifications: 1—compressed air and its regulating system, 1-3, are eliminated; and 2—a vacuum system, 16, equipped with a vapor trap, 15, and a vacuum manometer, 17, is added. The vacuum system can be either a water aspirator or a laboratory vacuum pump. Any desired rate of airflow can be drawn into the glass cylinder, 13, by adjusting the opening of the air regulating stopcock, 10. The sucked air stream is cleaned by the purifying and drying system, 4-8, before entering the glass cylinder, 13. When this setup is used for vacuum frothing, the air regulating stopcock is closed. The frothmeter has been used for almost 3 years and has proved to give reproducible results, as illustrated in Table I. With a magnifying glass and suitable illumination, the frothmeter also can be used to study the attachment of air bubbles to coarse mineral particles.' Experimental Procedures Except where otherwise stated, the data presented were established by means of the compressed air method. The volume and persistence of froth were recorded respectively at the end of 4 and 6 min of aeration at a constant rate of airflow of 29.3 cc per sec, which is equivalent to 71.6 cc per sq cm per min, or 462.6 cc per sq in. per min. The aqueous solution for each test, containing 1000 cc of distilled water and 19.2 ± 0.5 mg frothing reagent, was adjusted to a pH of 6.9 0.2. The volume of froth is expressed as cubic centimeter per square centimeter and is equivalent to the height of the froth column (the distance between the bottom and the meniscus of the froth). The volume of froth was obtained by multiplying the height of froth by the cross-sectional area of the glass cylinder, 24.53 sq cm. Before each test, the glass cylinder, 13, was cleaned thoroughly with jets of tap water, ethyl alcohol, tap water, cleaning solution, tap water, and finally distilled water. The cylinder with stopcock,

Jan 1, 1953

By W. Rostoker, A. S. Yamamoto, K. Anderko

ALTHOUGH the corrosion resistance of magnesium and its alloys is closely related to iron content, there has been no direct measurement of the solid solubility of iron in magnesium. Bulian and Fahrenhors;1 and Mitchel]2 agree that pure iron or a limited terminal solid solution crystallizes from the Mg-rich liquid. For this reason a magnetic-moment method was selected to estimate that portion of the total iron content which is not in solid solution. Since iron in solid solution in magnesium cannot contribute to ferromagnetism, the difference between chemical and magnetic-iron analyses should yield the solid solubility. By experimentation it was found that the melting of pure sublimed magnesium (99.995 wt pet purity) in Armco-iron crucibles at about 800°C is a convenient way to introduce small amounts of iron. Melts retained 5, 10 and 20 min at 800°C analyzed 0.003,, 0.005,, and 0.018 & 0.001 weight pet Fe, respectively, after being stirred, heated to 850°C, and cast into graphite molds. The as-cast alloys were pickled in acid (dilute HC1 + HNO3), annealed at 600°C for 3 days, scalped on a lathe to remove the pitted surface, pickled again, extruded at about 100°C to 3-mm wire, reannealed 41/2 days at 500°C, and water-quenched. The specimens were again scalped, pickled, and used both for chemical and for magnetic analysis. Most of the precautions described were intended to prevent iron pickup by contact with tools or superficial iron enrichment by volatilization of magnesium during heat-treatment. It is believed that the specimens ultimately used for test were homogeneous and characteristic of phase equilibria at 500°C. Magnetic Analyses A susceptibility apparatus of the Curie type was used for magnetic analyses. Field strengths of up to 10,400 oersteds could be generated. By this method, an analytical balance measures the force of attraction which a calibrated magnetic field exerts on a suspended specimen. The force equation is as follows f/m = M dh/dy where f/m = force per unit mass of sample M = magnetic moment per unit mass dH/dy = magnetic field gradient The dH/dy characteristic of the instrument is determined by the use of a standard palladium sample, and the calibration is made independently for all values of H. Since a large finite field is required to saturate an assembly of ferromagnets, it is necessary to measure the apparent magnetic moment for increasing steps of H until a saturation value is obtained. The percentage of iron in the sample as free ferromagnetic iron may then be computed simply C= 100 (M1/M1) where C = percent content of undissolved iron in sample M1 = saturation magnetic moment of sample per unit mass M1 = saturation magnetic moment of iron per unit mass taken as 217 emu-cm per gm There is no serious difficulty in applying this method except for the unusual magnetic behavior of very fine particles of ferromagnetic substances. It has been found and is the basis for a widely accepted theory that with sufficient subdivision, the magnetic fields required to saturate and the coercive force after saturation rise to exceedingly high values. Recent work on precipitates of Fe and Co from copper solid solutions8 showed that about 5000 oersteds were necessary to approach saturation. The magnetic moments as a function of field strength measured in the present investigation are listed in Table I. Only the 0.018 wt pet Fe alloy yielded a magnetization curve with a fairly well-defined saturation plateau at 3.76x10 -2 emu-cm/ gm. This corresponds to 0.017 & 0.001 wt pet Fe in the alloy. This indicates that the solid solubility must be of the order of 0.001 wt pet Fe. The magnetic-moment data of the other two alloys are badly scattered, indicating that the amount of ferromagnetic iron in these samples is so low that the magnetic forces acting on them cannot be measured accurately by the analytical balance used. Nevertheless, the fact that even the 0.003, wt pet Fe alloy shows ferromagnetism indicates that the solid solubility must be below that value. Acknowledgment This work was sponsored by the Pitman-Dunn Laboratory of Frankford Arsenal, Philadelphia, Pa. The support and permission to publish are gratefully acknowledged. References W. Bulian and E. Fahrenhorst: Zeic. Metallkunde, 1942, vol. 34, pp. 116-170. 2 D. W. Mitchell: AIME Transactions, 1948, vol. 175, pp. 570-578. 3 G. Bate, D. Schofield, and W. Sucksmith: Philosophical Magnsine, 1955, vol. 46, pp. 621-631.

Jan 1, 1959

By Shiou-Chuan Sun

THIS paper presents the design and operation of a frothmeter capable of measuring the frothing characteristics of pine oils and other frothing reagents. The experimental data show that the froth-ability of pine oil is governed by: 1—rate of aeration, 2—time of aeration, 3—height of liquid column, 4—chemical composition of pine oil, 5—pH value of solution, 6—temperature of solution, and 7—concentration of pine oil in solution. The effect of mineral particles on the behavior of froth also was studied, and the results can be found in a separate paper.' The results also show that the relative froth-abilities of pine oils in the frothmeter generally correlate with those in actual flotation, provided that other factors are kept constant. In addition to pine oils, the other well-established flotation frothers were tested, and the results are included. In this paper, compressed air frothing is the frothing process performed by means of purified compressed air, whereas sucked air frothing is the frothing process accomplished by purified air sucked into the glass cylinder by a vacuum system. The term vacuum frothing denotes that froth was formed by degassing of the air-saturated liquid under a closed vacuum system. Apparatus The frothmeter, shown in Fig. 1, is capable of re-producibly measuring the volume and persistence of froth as well as the volume of air bubbles entrapped in the liquid and is capable of being used for compressed air frothing, sucked air frothing, and vacuum frothing. Fig. la shows that for compressed air frothing, the apparatus consists of an airflow regulating system, 1-3; a purifying and drying system, 4-8; a standardized flowmeter to measure the rate of airflow from zero to 500 cc per sec, 9; and a graduated glass cylinder, 13; equipped with an air regulating stopcock, 10; an air chamber, 11; and a fritted glass disk to produce froth, 12. The fritted glass disk, 5 cm in diam and 0.3 cm thick, has an average pore diameter of 85 to 145 microns. The pyrex glass cylinder has a uniform ID of 5.588 cm and an effective height of 63 cm. The inside cross-sectional area of the glass cylinder was calculated to be 24.53 sq cm, or 3.8 sq in. For sucked air frothing, Fig. lb shows that the apparatus for compressed air frothing is used again, with the following modifications: 1—compressed air and its regulating system, 1-3, are eliminated; and 2—a vacuum system, 16, equipped with a vapor trap, 15, and a vacuum manometer, 17, is added. The vacuum system can be either a water aspirator or a laboratory vacuum pump. Any desired rate of airflow can be drawn into the glass cylinder, 13, by adjusting the opening of the air regulating stopcock, 10. The sucked air stream is cleaned by the purifying and drying system, 4-8, before entering the glass cylinder, 13. When this setup is used for vacuum frothing, the air regulating stopcock is closed. The frothmeter has been used for almost 3 years and has proved to give reproducible results, as illustrated in Table I. With a magnifying glass and suitable illumination, the frothmeter also can be used to study the attachment of air bubbles to coarse mineral particles.' Experimental Procedures Except where otherwise stated, the data presented were established by means of the compressed air method. The volume and persistence of froth were recorded respectively at the end of 4 and 6 min of aeration at a constant rate of airflow of 29.3 cc per sec, which is equivalent to 71.6 cc per sq cm per min, or 462.6 cc per sq in. per min. The aqueous solution for each test, containing 1000 cc of distilled water and 19.2 ± 0.5 mg frothing reagent, was adjusted to a pH of 6.9 0.2. The volume of froth is expressed as cubic centimeter per square centimeter and is equivalent to the height of the froth column (the distance between the bottom and the meniscus of the froth). The volume of froth was obtained by multiplying the height of froth by the cross-sectional area of the glass cylinder, 24.53 sq cm. Before each test, the glass cylinder, 13, was cleaned thoroughly with jets of tap water, ethyl alcohol, tap water, cleaning solution, tap water, and finally distilled water. The cylinder with stopcock,

Jan 1, 1953

By Louis V. Bender, R. E. H. Pomeroy, David H. Browne

E. P. Mathewson, Anaconda, Mont.—After hearing about the success of D. H. Browne with his furnaces, we in Anaconda decided we might venture into the field of pulverized coal for reverberatory smelting. We sent a delegation of investigators to see Mr. Browne and his work, and they returned, filled with enthusiasm, and said they would recommend it strongly.. We thereupon asked for an appropriation, and after some delay obtained the same and fitted up one furnace to use pulverized coal. We copied Mr. Browne's practice and his selection of machinery for drying and pulverizing coal; and we also copied the burner he used, which was a standard article on the market. We got an expert coal-dust machinery man to design our plant, and were very glad we did so as we avoided some of the unpleasantness that had been experienced at other plants through fires and minor explosions. I want to say, before describing our apparatus a little in detail, that we were quite familiar with the work of Mr. SÖrensen, the pioneer in the use of pulverized coal for copper smelting. Our attention had been called to it by Mr. Klepetko early in the game. And afterward we were familiar with the work done at Cananea by Mr. Shelby. We sent an expert to investigate the question 10 years ago. He examined the work of Mr. SÖrensen; and then went to the cement men and examined their work, and reported at great length that coal dust was the ideal fuel for them, as they took the ash from the coal and sold it as cement. He reported that coal-dust firing could not be made economical in reverberatory copper smelting, and his reasons were that a blanket of nonconducting material would cover the charge in a short time and insufficient heat would reach the charge proper, and we would have floaters over all our furnaces. The flues would be stopped by the dust that did not settle on the charge. We accepted that until our Irish friend got busy and showed us how to do it. Then we built a furnace which we thought was a slight improvement over Mr. Browne's. We put railroad tracks over our furnaces to draw the charge to the furnace. We had

Jan 1, 1915

He was born at Montreal, Canada, in 1875. His earliest education was received in Montreal hut was continued from 1885 to 1892 at schools and academies in Brooklyn, Whitestone, and Flushing, L. I. For his technical education he returned to McGill University, where he graduated in 1897. His first professional occupation was as transitman enga.ged in the running of township lines in the Rainy River District of Ontario. In 1899, he was made assistant chemist at the Cuggenheim smelter at Aguascalientes, Mexico. From 1900 to 1903, he was chief chemist for La Compañia Minera de Peñoles, at Mapimi, Durango. We have no information as to his pursuits during the next eight years, but from 1911 until 1914, when he became a member of the Institute, he was chief engineer for the Bankhead mines in Alberta, Canada. Lieutenant-Colonel Alfred Winter Evans Lieutenant-Colonel Evans, who was in command of the Third Battalion of the New Zealand Rifle Brigade, and had been cited in Distinguished Service Orders and received the Distinguished Conduct Medal, was killed in action on Oct. 12, 1917. Alfred Winter Evans was born in Natal, South Africa, in 1881, and received his preliminary education in the Durban High School. For the next five years he attended St. George's School at Harpenden Heights, England, until 1898. Returning to South Africa, he worked . for three months of 1898 as underground sampler for the Crown Deep Gold Mining Co., at Johannesburg, and for six months of the following year he was shift-boss for the Crown Deep, Ltd. At the outbreak of the Boer War he took an active part and was engaged on military service from 1899 to 1902. At the close of the mar, he came to New York and attended the Columbia School of Mines, where he graduated with the degree of E. M. in 1906. A part of that year he spent as assayer to a mining company at Poland, Arizona. In 1907, he returned to South Africa and engaged as underground contractor in charge of mining and development at a number of the South African mines, notably the French-Rand, the ViIIage Main Reef, the City Deep, and others. In 1908, he acted as shift-boss for the Fer-rerra Gold Mining Co. at Johannesburg. In 1909, he was appointed acting general manager for the Consolidated Goldfields of New Zealand,

Jan 1, 1920

I. PRESIDING OFFICER. At all business meetings of the Institute the President, or, in his absence, the First Vice-President, or, in the absence of both of them, any other Vice-President or Director, chosen by the meeting, shall preside. At all other meetings of the Institute the President, or, in his absence, one of the Vice-Presidents, shall preside. If none of these be present the meeting shall elect a Chairman. II. ORDER OF BUSINESS. At each business meeting of the Institute the order of business shall be as - follows : 1. Reading of minutes-of preceding meeting. 2. Report of the President. 3. Report of the Treasurer. 4. Report of the. Secretary. 5. Election of Directors. 6. Reports of Standing Committees. 7. Reports of Special Committees. 8. Special Orders. 9. Miscellaneous business. This order of business may be changed at any meeting, by a vote of a majority of the Members and Associates present. At all sessions of the Institute, other than business meetings, the order of pro¬ceedings and the time of adjournment shall rest in the discretion of the presiding officer. III. SECRETARY OF THE INSTITUTE. The Secretary shall keep a record of the proceedings of all meetings of the Institute. He shall be custodian of the corporate seal, of the minute books, and of all legal documents belonging to the Institute. He shall have charge, on behalf of the Institute, of all correspondence except such as pertains directly to the office of the Treasurer. He shall notify all Officers and Directors and all members of committees of their election and appointment; shall issue notices of all meetings of the Board, and of the annual and other business meetings of the Institute; and shall; in calling, special meetings of the Directors, specify the objects of such meetings. He shall act as clerk at all the meetings of the Board of Directors and at all meetings of the Institute. The Secretary shall be custodian of all technical or scientific papers submitted to the Institute for its consideration, shall have general charge and supervision of the editing and proof-reading of all material published by the Institute, and of the distribution thereof, and be ex officer Chairman of the Committee on Publications. On the first day of May following the year in which each volume of Transac-

Jan 1, 1925

By N. J. Grant, K. M. Zwilsky, J. T. Blucher

DISPERSION strengthening has been studied in a number of metal-metal oxide systems. To date those pure metals available as fine particles (less than about 5 p) have received most of the attention whereas solid solution alloys, generally unavailable as fine powders, have not been examined in detail. The present work was undertaken as a preliminary study to evaluate combined effects of solid solution and dispersion strengthening. The technique used was that of dry mixing of elemental powders with the oxide, followed by a diffusion treatment to obtain the solid solution. The average particle size of the powders used was: Ni, 3.2 p (1nco B); Mo, 1.3 p (Fansteel Metallurgical Corp.); and y alumina, 0.027 \i (G. L. Cabot, Inc.). The particle size of the metal powders was determined by Fisher subsieve measurements while the size of the alumina was calculated from a surface area determination. Prior diffusion studies on small compacts pressed from mixtures of nickel and molybdenum powders with and without 7.5 vol pct A1203 indicated that diffusion was complete after sintering for 100 hr at 1800" , or 50 hr at 2250", or 20 hr at 2550° F. The progress of diffusion was followed by microstructural examination and micro-hardness measurements. Two observations made during the diffusion experiments were: 1) That diffusion proceeded faster in the presence of alumina, confirming similar findings by Seith and Loepman on "SAP'';4 2) That diffusion at temperatures above 1800°F resulted in coarsening of the alumina in agreement with results of other authors reporting on the growth of alumina in nickel above 1800"F. Similar experiments in the Ni-Cr system using 6 and 20 p Cr powders of 0.7 and 0.025 pct 0, respectively, did not result in significant solid solution formation even after long time exposures at 2550° F. It must be concluded that chromium oxide films around individual particles interfere with normal diffusion. A nickel alloy containing 5 wt pct Mo and 7.5 vol pct alumina was fabricated by dry mixing of powders, isostatically compacting at 30,000 psi, diffusing for 120 hr in dry hydrogen at 1800" F, and extruding at 1950"~ with a 30 to 1 reduction of area ratio. The resulting structure, presented in Fig. 1

Jan 1, 1963

By J. Weijdema, D. N. Dietz

In the conventional underground combustion process (dry combustion) much heat is left behind in the swept formation and goes to rva.rte. Econonmy can be improved by heat recuperation through water injection. This is most advantageous if done at the earliest opportunity before much heat is dissiputed to cap and base rock. Water injected simultaneously with the air will flash to superheated steam, which passes through the combustion front together with the nitrogen from the air. A condensation front traveling up to three times as fast as the combustion front drives out the oil. In this type of wet combustion, the water evaporates before it reaches the combustion zone. The evaporation front travels more slowly than the combustion zone. If so much water is injected that the evaporation front overrun the combustion front, combustion in that spot will be quenched and some unburned fuel will be left behind. Air reacts with the oil farther down-stream where steam temperatures occur; at steam temperature, the air reacts rapidly with the oil. Velocity of the combustion front is increased thereby and is governed essentially by the water-injection rate. In the extreme case of high water-injection rate, a short heat wave of constant length is driven through the formation by water injection. Once this wave has been established, no more heat need be generated than that required to make up the heat losses from the short heat wave; a relatively low rate of air injection will suffice. The feasibility of partially quenched combustion has been confirmed in tube experiments. A heat wave at steam temperature is observed. Chemical analyses of flue gas indicate preferential burning of hydrogen while a carbonaceous residue is left in the formation. Introduction A disadvantage of so-called dry in situ combustion is that air-compression costs are rather high. An air consumption of about 400 std cu m/cu m (400 scf/cu ft) of formation swept is an accepted figure. This high consumption is mostly wasted since much heat is left behind in the depleted oil sand. Methods were investigated for recuperating as much as possible of the heat left behind. This paper deals only with basic principles and is confined mainly to one-dimen- sional flow without lateral heat losses; experiments were conducted in relatively narrow, well insulated tubes. If some water is injected with the air, it will turn to superheated steam in an evaporation front, which should travel behind the combustion front. The steam having passed the combustion front causes a steam drive by a condensation front that can travel faster than the combustion front. The latter needs to travel only part of the distance covered by the oil-displacing condensation front, and thus consumes less air. The water-air ratio would seem limited to that at which cold water overruns the combustion. This limitation was deliberately exceeded considerably in theory and experiments. It was found that combustion is then indeed quenched, but only locally. Farther downstream, the oxygen finds residual oil at steam temperature, which is suficiently high to ensure rapid oxidation. Thus, the combustion front uses only part of the available fuel because it is chased through the formation faster than its normal velocity. No heat is left behind. This new process is called "partially quenched combustion". At the upper limit of the water-air ratio, a small heat slug is moved through the formation by the flow of water and steam. Only a small flow of air is needed since it has only to generate sufficient heat to make up for the lateral heat losses of the short heat slug. Theory Although many factors complicate underground combustion, the processes will be presented in their simplest form. For this reason, one-dimensional flow without lateral heat losses is assumed. Heat conduction in the direction of flow also is disregarded. Under these conditions, dry combustion causes very high temperatures. The heat-carrying capacity of the gas stream is small. Heat generated by oxidation of a residual oil saturation is retained in the sand. The available fuel determines the air requirement and the temperature obtained. Accepting the often-mentioned air consumption of 400 std cu m/cu m (400 scf/cu ft) formation, we calculate a temperature of the swept sand of 1,200C (2,192F) (Fig, I). If water is injected at a modest rate with the air, it will flash to superheated steam upon contact with the heated sand. One cu m (35.31 cu ft) of hot formation will evaporate about 0.5 cu m (17.66 cu ft) of water, and thereafter will accommodate (at an estimated 0.80 saturation and an assumed 0.40 porosity) another 0.3 cu m (10.59 cu ft) of water in cold condition. As long as less than 0.5 + 0.3 = 0.8 cu m (28.25 cu ft) of water is injected for every 400 std cu m (14,125 scf) of air (water-

Jan 1, 1969

By J. R. Long, T. R. Graham, C. W. Matthews, R. S. Dean

IN a previous paper§ the authors reported on the mechanical properties of a 65 per cent copper, 10 per cent manganese, 25 per cent zinc alloy as compared with similarly processed cartridge brass. Additional investigations by these laboratories, on higher copper alloys, have demonstrated that at lower zinc concentrations even larger amounts of pure manganese may be added to copper-zinc alloys without exceeding the single-phase solid solution limits, and that similar increases in tensile strength, yield strength, and hardness may be obtained without excessive decreases in ductility. Several compositions in this range showed also a decided color change with increasing manganese. The normal "brassy" color was considerably lightened and reduced to a faint yellow cast at 15 per cent manganese. With higher manganese contents the alloys were essentially white and similar in appearance to the nickel-silver alloys. From this work it appeared that it would be desirable to determine more completely the properties of the wrought and annealed white alloys. Accordingly, a more detailed study was planned of an alloy having the composition 70 per cent copper, 20 per cent manganese, and 10 per cent zinc. This alloy remained single-phase throughout the working and annealing cycles of the preliminary tests and appeared to be about the strongest of the white single-phase alloys. The project included also an investigation of additional alloys, deviating from this composition by 5 per cent of each of the three components to evaluate the effects of variation in composition; also a study of the properties of the central alloy made with silicothermic manganese. MATERIAL PREPARATION Electrolytic manganese, wirebar copper, and electrolytic zinc were used for the preparation of the alloys. Representative analysis of the electrolytic manganese seldom exceeds 0.01 per cent iron, 0.02 per cent sulphur and 0.02 per cent lead, with no silicon or aluminum. A typical sample of the silicothermic manganese metal contained 2 per cent iron, 0.81 per cent silicon, 0.i6 per cent carbon, and 0.36 per cent aluminum. Melting and alloying were performed in a high-frequency furnace with magnesia crucibles. Melts were deoxidized with small aluminum additions and cast into 25-lb. slab ingots. Care was exercised in deoxidation to avoid excessive amounts of residual aluminum, which has been found to have significant effects on alloys in this system. All ingots were hot-rolled at 1200° to 1300°F. and then cold-rolled with intermediate anneal-

Jan 1, 1945

By James C. M. Li

The Petch relation between the flow stress and the gain size is derived from a consideration of gain boundary sources of dislocations without the need of dislocation Pile-ups. Three mechanisms for inierpreting the yield stress: the gain boundary strength, the unpinning of Frank-Read source near a grain boundary, and the generation of dislocations from the grain boundary are compared and the condition of their equivalence is shown. The effect of the average angle of misfit of pain boundaries is found to be sma11 and so is that of the average angle of misfit of subboundaries having impurities. The effect of impurities on the ledge density in the grain boundary is treated thermodynamically and a relatwn is proposed for the variation of Petch slope with impurity activity. The effect of temperature on the Petch slope is interpreted as due to the change of ledge structure in the grain boundary. It is indicated that the effect of annealing temperature may be more important than that of the test temperature and therefore should be studied. The effect of plastic strain on the Petch analysis is deduced from a work-hardening equation in which the generation of dislocations has first-order kinetics and the annihilation of dislocations has second-order kinetics. It is concluded that the Petch slope will decrease with plustic strain if the rate of annihilation of dislocations is sufficiently large. Critical experiments which may shed light on the mechanism for the Petch relation are suggested. THE relation between the yield or flow stress, 0, and the grain size, l, was first proposed by all' and later studied more extensively by Petch and co-workers, who also proposed a similar relation for the fracture stress and deduced from these a grain-size effect of the ductile-brittle transition temperature. The microscopic mechanism used by all' and petch2 involves a pile-up of dislocations of like sign generated from a Frank-Read source. The yielding or flow takes place when the pile-up exerts sufficient stress at the grain boundary so that the plastic deformation can propagate from one grain to another. If the average strength of the grain boundary is ai and the average length of the pileup is lp, the Petch slope, k, is given by" where p is the shear modulus, b the Burgers vector, and v the Poisson ratio. This slope will be independent of the grain size if l/lp is a constant. This is possible, since, if the Frank-Reed source is situated near the grain boundary, lp = 1, and if it is situated in the middle of the grain, Ip = 1/2. cottrell,12 also using the pile-up mechanism, proposed that the stress concentration at the grain boundary will initiate Frank-Read sources near the grain boundary and in this manner a Lüders band can propagate from one grain to another. Assuming that the average distance between the Frank-Read sources and the grain boundary is 1, and the unpinning stress of the Frank-Read sources is op, Cottrell obtained the following Petch slope: This slope will be independent of the grain size if ls is independent of the same, which is not as obvious as the condition, Ip = I for Eq. [2]. In addition to this assumption, the direct relation between the Petch slope k and the unpinning stress, up, was recently questioned by Johnsonon grounds that it is inconsistent with the following observations: the independence of k with temperature and strain rate, and the small k in columbium, which, like iron, has a sharp yield point. As pointed out by ohnson," the most important objection both to the Hall-Petch mechanism, in which the strength of the grain boundary plays the role in yielding, and to the Cottrell mechanism, in which the unpinning of Frank-Read sources plays the role in yielding, is the lack of direct observation of the pile-ups. The dislocation structure in deformed iron has been examined recently in the electron microsope.'-' Dislocations appear to be generated from grain boundaries or other interfaces; they form clusters and tangles within the grain at very early stages of deformation, even in the Lüders band, if the deformation is slow or at normal and elevated temperatures. Although it is still too early to interpret bulk properties from thin-film observations, it does seem worthwhile to look for a mechanism for the Petch relation which does not require dislocation pileup. SUBBOUNDARY SOURCES In order to show that a consideration of grain boundary sources can lead to the same Petch relation as does the consideration of the strength of the grain boundary, we shall first discuss the case of a simple tilt boundary whose elastic properties have been studied in detail.17 The strength of a partially

Jan 1, 1963

By R. H. Jacoby, V. J. Berry

When dry gas is injected into a reservoir containing a volatile crude oil, a significant amount of the reservoir liquid phase may become vaporized. The resultant rich gas phase, when subsequently produced, con-tributes to tank oil production. This contribution assumes greater importance, the more volatile the oil in-olved. Oil recovery may be sub-stantially greater than that predicted by conventional frontal-drive methods, which do not consider the vaporization equilibrium between the reservoir oil phase and the injected gas. A calculation method has been (developed to account for vaporiza-. tion of the reservoir liquid phase during gas-injectiorz operations, and for the tank oil production which results from this factor. Recovery performance calculations are presented for a reservoir containing a highly volatile oil. Tank oil recovery is calculated to be about twice that predicted by the use of the conven-rional frontal-drive equations. In contrastto usual pressure maintenance performance results, in which the gas-oil ratio rises at an increasing rate after gas breakthrough, the pre-dicated gas-oil ratio rises rapidly to about 12,000 scf/bhl and then rises much less rapidly. During gas inje-tion, most of the reservoir liquid phase contacted is evaporated by the dry injection gar. The gas-oil ratio during this period is dependent upon reservoir pressure. The higher the operating pressure, the lower the gas-oil ratio. The predicted behavior i., in accordance with laboratory PVT tests made to .simulate the vaporization behavior. In addition to recovery performance predictions, results of the calculation procedure include complete wellstrearn composition data of value in the design of gasoline plant facilities often used in con-rrction with gas-injection operations. INTRODUCTION In the cycling of gas-condensate reservoirs, dry gas is injected to maintain reservoir pressure during wet gas production and to thereby eliminate or reduce ultimate loss of liquids due to retrograde condensation within the reservoir. Gas injected into crude oil reservoirs has a dual function. It displaces oil to the producing wells and at the same time serves to partially or fully maintain reservoir pressure. Oil shrinkage which would occur upon pressure reduction is thereby minimized or eliminated. Accepted calculation methods are available'= for predicting recovery performance of either gas-condensate reservoirs or crude oil reservoirs which are being subjected to gas injection. In gas-condensate reservoirs, any retrograde liquid formed does not flow, and it is necessary to account only for the vaporization equilibrium between this liquid and the injected gas. Conversely, in normal crude oil reservoirs, both the oil and gas phases flow, but it has not been considered necessary to account for any vaporization of the reservoir liquid which might occur upon contact with the dry injection gas. Recently, high shrinkage reservoir fluids known as "volatile oils" have been found in increasing amounts. These oils are characterized by tank oil gravities above 4.5" API, solution gas-oil ratios above 1,000 scf/bbl, and reservoir volume factors above two. Special techniques have been devised for predicting depletion performance of reservoirs containing such oils.74.5.1; One of the characteristics of reservoirs producing volatile oils is that the reservoir gas phase carries a significant amount of oil which is recoverable as stock-tank liquid. This unusual vaporization be-havior implies that an appreciable amount of reservoir liquid would be vaporized upon contact of the oil with dry injection gas. In a gas-injection operation, tank oil recovery would he obtained not only through frontal displacement of the reservoir liquid by the injected gas, but also through production of the rich gas phase. This means that not only are improved methods needed to predict recovery of such oils from reservoirs undergoing gas injection, but it would also be expected that high oil recoveries might be obtained by such operations. When relatively dry gas is injected in to a volatile oil reservoir, phase equilibrium between the injected gas and the reservoir oil will tend to bc established. Initially the most volatile components, such as propane, the butanes and the pentanes, will account for most of the material transferred from the oil phase to the gas phase. As the partially stripped oil phase is contacted with additional dry injection gas, the heavier intermediate components, such as the hexanes, the heptanes and the octanes, will gradually transfer to the gas phase in increasing amounts. This is because the supply of lighter components in the oil phase dwindles due to the stripping action of the injected gas. This stripping action will usually continue to be effective down

By William P. Mason

FoR reasons unnecessary to enter into here, I was called upon to contradict the statement that " closed metallic vessels, partly filled with water and heated, do not become shattered by violent explosion, but simply rupture by over-pressure;" and the following experimental results were obtained in support of my position : A piece of drawn brass tubing (telescope-tubing) 1 1/2 inches in diameter and 15 inches long was closed at both ends by screwing on heavy caps of bronze. Before closing the second end the vessel was half filled with river water, the cap was then screwed on, and the closed vessel was supported upon two iron anvils, and heated in the interval between the supports by a large Bunsen lamp. The resulting explosion (which was doe to over-pressure only and not to any more occult cause) was exceedingly violent. No small damage was done to the room in which the experiment was undertaken; and the noise was like that of a cannon. Those of the pieces which could be recovered are shown in Fig. 1. Upon examining the wreck, it was noticed that one of the heavy bronze end-caps had preserved its circular section and still contained that portion of the barrel of the tube which had been screwed into it, while the other end-cap contained no portion of the tube, and was moreover sprung into a shape more or less elliptical, as if from excessive lateral strain. It was also observed that the large pieces of the shattered boiler predominated towards the end which had been closed by the un-sprung end-cap. The reasonable explanation, in view of the facts, was, that over-pressure had caused the boiler to yield through the screw-threads at A B, Fig. 2, and the righthand end-cap had blown off, thus leaving the boiler half filled with water, greatly super-heated for the new (atmospheric) pressure to which it was suddenly reduced; that this water had consequently sprung instantly into steam with dynamite effect, shattering the tube and springing the remaining end-cap. The large pieces would be expected at the open end of the boiler, as at that point the "tamping "would have been that of the atmosphere only. This explanation assumes a rupture to have been caused by gradually increased pres-

Jan 1, 1893

By D. Y. F. Lai, R. J. Borg

Tracer diffusion of Fe59 has been measured in the a-stabilized Fe-1.8 at. pet V alloy from 700° to 1500°C. The activation energies are obtained in both the presence and absence of magnetic order. Furthermore, it is established that diffusion in the alloy is identical to that in pure iron and consequently the values of Do and Q accurately represent the temperature dependence for self-diffusion. The purpose of this investigation is to obtain an accurate estimate of the temperature dependence for self-diffusion in bee iron in both the presence and absence of magnetic order, and, in so doing, to establish the temperature range of the magnetic effect.&apos;" As the temperature interval suitable for diffusion measurements is severely limited in both bee phases of pure iron because of the intervening fee ? phase, the experiments were performed on an a-stabilized alloy containing 1.8 at. pet V. This alloy is bee over the entire range from room temperature to the melting point. Although there have been several independent investigations of self-diffusion of iron in a, iron,1, 3-6 there still exists considerable disagreement regarding the values of Do and Q for the paramagnetic region. The two systematic studies of diffusion in 6 iron6, 7 previously reported are also only in fair agreement; but in view of the extremely small temperature range available for diffusion studies, i.e., 1390o to 1535oC, this is not surprising. It is comparatively easy to obtain accurate values of Do and Q for the a-stabilized alloy inasmuch as measurements can be made over the entire temperature range -700o to 1500°C. However, in order to assume that these same values apply to pure iron requires careful comparison of the data in the a, and 6 regions in both the alloy and pure iron. We have made several measurements in the appropriate temperature ranges and are unable to establish any systematic difference between the diffusion coefficients of iron in pure iron and in the alloy. We therefore conclude that the values obtained for the alloy are truly applicable to pure iron; the complete evidence favoring this conclusion will be discussed later in this paper. EXPERIMENTAL The experimental methods will be given here only in barest detail since they have been thoroughly de- scribed elsewhere.l, 7 The alloy was prepared by induction melting and chill casting under argon. Diffusion samples were machined from the ingot and annealed in hydrogen for several days at 900°C to give an average grain diameter of 1 to 2 mm. The penetration profiles of the tracer were established by a sectioning technique, the residual activity being counted after the removal of each section. The tracer used is Fe59 which emits two high-energy ? rays of 1.098 and 1.289 Mev, respectively; these were detected by a ? scintillation counter equipped with a pulse-height analyzer. For the measurements in the temperature range -700o to 1130°C the samples were vapor-plated with Fe59, encapsulated in quartz under vacuo, and annealed in resistance-heated furnaces which are controlled to ±1°C. The specimens diffused at higher temperatures are prepared as edge-welded couples, the two halves being separated by a thin washer of the alloy to prevent sintering. The diffusion anneal is then carried out by inductive heating under a dynamic vacuum. The temperature is monitored pyrometrically. RESULTS The diffusion coefficients are obtained from the penetration profiles in the usual way using the error-function complement relationship. The results over the entire temperature range are shown in Fig. 1. In the linear region, 900o < t > 1500°C the least mean squares (lms) values of the diffusion coefficients are given by D = 1.39 exp[-(56.5 ± 1) x 103/Rt] cm2/sec [l] The average departure of the measured diffusion coefficients from the values given by Eq. [1]In order to determine whether or not the slope is truly constant over the entire range from 900" to 1500°C, the data are arbitrarily divided into two groups, the first containing values between -900" and 1133°C and the second between -1133o and 1500°C. The lms values for the two groups are given by Eqs. [2] and [3]: D = 0.519 exp[-55.7 x 103 /RT](900° to 1133°C) cm2/sec [2] D = 1.45 exp[-56.7x103/RT] (1133° to 1500=C) cm2/sec [3] Thus, there is no significant difference between the high- and low-temperature segments of the linear region. This not only assures us of the consistency of the values obtained by induction heating as compared to those obtained from the resistance-heated

Jan 1, 1965

By S. G. Epstein

Using the capillary-reservoir technique, electromi-gvation rates of cadmium and indium in liquid bismuth were measured at several temperatures. The electric mobility of cadmium Jrom 305° to 535°C and indium from 310° to 595°C can be expressed as a function of temperature by the equations UIn = 1.52 x 10-3 exp sq caz per v-sec Migraion of both solutes was cathode-divected at a rate rnore than four tiMes tHAt previously found for siluer in liquid bisnmth. The electric mobilities of cadmium and indiulrz in liquid bismuth at 500° C are nearly identical with their respective mobilities in mercury at room temperature. AS part of a systematic study of the variables which are considered to control electromigration in liquid metals, the electromigration rates of cadmium and indium in liquid bismuth have been measured. Mass transport properties of silver in liquid bismuth have been reported previously,&apos; and measurements of tin and antimony in liquid bismuth are forthcoming. Comparisons will be made with literature values for these same solutes in mercury.2&apos;3 This series of solutes was selected to determine the effect of the solute valence on its electromigration. Silver, cadmium, indium, tin, and antimony have nearly equal atomic masses but have chemical valences ranging from +1 to +5. They are all fairly soluble in bismuth above 300°C and all have radioactive isotopes, which are an aid in making analyses. EXPERIMENTAL TECHNIQUE Electromigration of cadmium and indium in liquid bismuth was measured by the modified capillary-reservoir technique previously described.&apos; In this method irradiated cadmium or indium is added to bismuth to form alloys containing about 1 wt pct solute (<2 at. pct solute). Several quartz or Pyrex capillaries: 1 mm ID and 5 cm long, vertically oriented, are simultaneously filled in the reservoir of the liquid alloy. A direct current is passed through two of the capillaries, which contain tungsten electrodes sealed in the upper end. The other capillaries sample the reservoir during the experiment. After a measured time interval the capillaries are removed from the reservoir and rapidly cooled. The glass is then broken away from the solidi- fied alloy, which is then weighed, dissolved in acid, and analyzed for solute content by chemical and radiochem-ical techniques. An electric mobility (velocity per unit field) can be calculated from the amount of solute entering or leaving each capillary by the simplified expression1 in which Ui is the electric mobility of the solute, ?mi the solute weight change, Ci the solute concentration of the reservoir, I the current, p the alloy resistivity, and l the duration of the experiment. This expression is valid as long as the experiment is terminated before a concentration gradient develops across the capillary orifice. Earlier experiments showed that the concentration gradient formed initially at the electrode changes with time and eventually reaches the orifice, due to back-diffusion. This condition produces a solute exchange between capillary and reservoir by diffusion or convection, opposing the electromigration, which results in a lower measured value for the electric mobility. To determine if the concentration gradient had reached the orifice, the capillaries used in some of the experiments were sectioned at 1-cm intervals and the solute content of the alloy from each section was radiochemically determined. A typical concentration profile for an experiment with indium in bismuth is shown in Fig. 1; cadmium in bismuth showed similar behavior. As illustrated in the graph, very little back-diffusion has occurred in the capillary containing the cathode, since the concentration gradient is confined to the upper 1 cm of the capillary. In the capillary containing the anode, however, the concentration gradient is much broader, extending nearly to the orifice, even though the net change in solute concentration is nearlv the same in both capillaries. Since cadmium and indium probably lower the density of bismuth when alloyed, depletion of the solute from the alloy adjacent to the anode would increase the density of the liquid in the uppermost region of the capillary. This would give rise to convective mixing within the capillary, causing the broadened concentration gradient. Conversely, the alloy adjacent to the cathode should have a reduced density as the solute concentration is increased by migration, explaining the "normal" concentration profiles found in these capillaries. This disparity was not found for electromigration of silver in bismuth. Both metals have similar densities at the operating temperatures, and nearly symmetrical concentration profiles were found in the two capillaries of each exueriment. This density effect was also apparently encountered when an attempt was made to measure diffusion coefficients for indium in liquid bismuth by the same technique which was successfully used to measure diffusion of silver in bismuth.&apos; Capillaries 1 mm ID and 2 cm

Jan 1, 1968

By Ralph Hultgren

IN solid solutions atoms of differing sizes occupy the same crystalline lattice, requiring that some of them be compressed and others expanded. The energy involved has been called misfit strain energy and is an important concept of crystal chemistry. If the atomic sizes and elastic constants of interatomic bonds are known, the misfit energy may be calculated,&apos; provided certain simplifying assumptions are allowable. Usually, isotropic crystals are assumed and interatomic distances are taken to be the statistical average determined from X-ray diffraction. Such calculations yield values of the misfit energy of the order of 1 or 2 kcal per atom in alloys such as Au-Cu at compositions of 50 atomic pct. However, evidence has accumulated in recent times that atoms change their sizes with composition of alloys, implying electronic rearrangement of the bonds. The size changes have been found particularly by application of the X-ray method developed by Warren, Averbach, and Roberts.&apos; Thus, Averbach, Flinn, and Cohen3 determined radii in Au-Cu alloys. Oriani4 showed that these new radii led to a calculated misfit energy in disordered AuCu, which was decreased from the values calculated by the usual theory more than twenty-fold, to only 80 cal per g atom. Thermodynamic calculations from the phase diagram5 also show misfit energy to be no more than a few hundred calories per g atom in this alloy. The question of what electronic rearrangements are possible therefore becomes compelling in estimating misfit energy. In the following pages the results of certain calculations on the AuCu tetragonal superlattice are submitted. Conclusions drawn from these should be applicable in large degree to disordered solid solutions. As in all ordered states, bonding distances in the superlattice are individually known, rather than being merely average distances as found from lattice constants of disordered states. Moreover, only the Au-Au and Cu-Cu distances are strained; the elastic constants of these are known in the elementary state. In the usual calculation it is necessary to assume elastic constants for Au-Cu bonds. Misfit energy has thus been calculable without the need of many simplifying assumptions usually made. It is still assumed that equilibrium bond lengths and elastic properties of the bonds are the same in the alloy as in the pure metals. As previously discussed, this is probably not correct. Also assumed is that the bonds are not affected by strain of neighboring bonds. A calculation of Young&apos;s modulus from compressibility data shows this to be far from true; extensive electronic rearrangements take place. It would seem that misfit energy cannot be calculated from elasticity data for the elements. The usual methods may, however, give an upper limit which is often much higher than the true value. The question of electronic rearrangement is, of course, a complex one. Pauling&apos;s theory gives a simple, approximate treatment of the relation between type of bond and bond distance. This has been applied with some success to the Au-Cu system, as will be shown in a later section. Misfit Energy in Au-Cu Alloys Hume-Rothery and Raynor6 discuss the Au-CU system as a type example of strain energy. The gold atom is 12.8 pct larger in diameter than the copper atom, near the size factor limit beyond which solid solubility is severely restricted. They therefore consider the misfit energy to be large, a conclusion for which they believe they find evidence in the phase diagram. Gold and copper are completely miscible in the solid state, but the alloy has a minimum melting point at an intermediate composition. From this Hume-Rothery and Raynor conclude that the strain energy is nearly large enough to prevent miscibility; the phase diagram tends toward a eutec-tic type. In Ag-Cu, which has almost identical size relationships, solid miscibility is quite limited; whereas in Au-Ag, where atomic sizes are nearly the same, there is complete miscibility without a minimum in the melting point. From their arguments the heat of formation of Au-Cu would be expected to be endothermic or only slightly exothermic, that of Ag-Cu to be endothermic, and that of Au-Ag to be exothermic. Deviations, from Ve-gard&apos;s law of additivity of atomic radii support these conclusions, since Au-Cu and Ag-Cu both have pronounced positive deviations, and Au-Ag has a negative deviation. Nevertheless, Au-Cu alloys form exothermically; indeed, considerably more exothermically than Au-Ag, Table I. Hence, strain energy must be much less important in this case than Hume-Rothery and Raynor have supposed.

Jan 1, 1958

By R. E. Shinkosk

This paper outlines the development of a program for increasing the life of woolen bags used for filtering Dwight-Lloyd gases by treating the bags and gases with hydrated lime. Methods and apparatus are described for determining alkalinity of dusts, acidity and breaking strength of bag cloth. Procedure and results, based on several years of operation, are presented. DURING 1939, additional facilities were constructed in the Dwight-Lloyd Blast Furnace and Baghouse departments at the Selby, California, Plant of the American Smelting and Refining Co. In order to handle adequately the increased volume of gases from the resultant increase in production, it was necessary to increase gradually the amount of water used for cooling gases ahead of the sinter machine baghouse. As a result of this increased water cooling, the average bag life dropped from 27 months in 1939 to 14 months in 1941. (Table I). This drop in life meant an increased. bag cost, as well as lower recovery of dust and some curtailment of operation. During 1941, it was found new bags showed as high as 0.3 pct acidity* after two weeks of opera- tion and as much as 2.0 pct acidity after some months of operation. This high acidity was present in spite of the fact that free oxide or relative alkalinity of the unburned dust ran from 5 to 6 pct. In view of these circumstances, a twofold program was started in Nov. 1941.t Part one of this program consisted of vigorously dipping all new bags in a weak lime solution, containing 50 lb of hydrated lime per 50 gal of water. Part two consisted of feeding fine, dry, hydrated lime into the gas stream intake of the sinter baghouse fan. Apparatus for feeding this lime is shown in fig. 1. All baghouse chambers are shaken in rotation about once each hour. On alternate hours, the baghouse operator places 50 lb of hydrated lime (one sack) into the lime feeder, starts feeder and immediately starts the bag shaking machinery. The rate at which lime is fed is set to coincide with the approximate time necessary to shake all sinter bag-house chambers, or about 15 min. It is felt this method of lime addition is most effective for getting lime into the woolen bag fabric. The amount of lime so fed averages about 600 lb per day. The amount of lime fed per day is varied to keep a minimum relative alkalinity of 9 pct in the unburned sinter dust. A daily dust sample is taken for alkalinity by allowing dust to accumulate in a sample pipe over a 24-hr period. This sample pipe, placed in any chamber cellar, is 2 in. in diam, 4 ft long, is sealed on the inner end, and capped on the outer end. It has a 1/2 in. slot cut for 18 in. along the tip end. This slot faces upward and allows the pipe to fill gradually with dust as bags are shaken. Breaking strength of bags has, in most cases, been the deciding factor in bag replacement. Bags that normally test 100 psi breaking strength when new are replaced when they test under 35 lb. The method for determining breaking strength is shown in the description accompanying fig. 2. Since the start of the liming program in 1941, bag life has increased from 14 months to an average of over 23 months, with a consequent material decrease in bag cost per year. Acidity, as per cent sulphuric acid, may be determined by means of a Beckman pH meter as follows: From a piece of bag cloth. which has been thoroughly cleaned of dust, a 5 g sample is weighed on a balance. Cut the sample into fine pieces and place in a 400 cc beaker. Add 100 cc (measured) of distilled water and stir vigorously. Filter on suction funnel, holding cloth pulp in beaker with a stirring rod. Wash cloth sample and filter wash water four additional times, each time with 20 cc distilled water, the last time squeezing cloth pulp over funnel. Discard pulp and rinse funnel and filter paper. Pour wash solution jnto measuring graduate and make up to exactly 300 cc with distilled water. Place into clean 600 cc beaker and measure the pH on meter. The per cent acid in bag cloth is read from the following table:—

Jan 1, 1951