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By M. M. Slotnick

It was once aptly said that a sign of approaching senility is ceasing work on a subject and beginning to talk about it. Perhaps that explains why, after many Years in which Part of my duties has been the training of college men in various branches of petroleum exploration geophysics, I have now begun to talk about it. In making an outline of what I believe ought to be discussed under the general heading of the title, I found it almost impossible to subdivide the ideas into an ordered set of discrete subjects. Rather, the pertinent remarks seemed to interlock almost everywhere. The consequence is that it will be necessary to start with the conclusions and then try to justify them by jumping back and forth. However, based on the types of men with whom I have had to deal, the subject naturally divides itself into two parts. In the first part, I should like to deal with the case of those undergraduates whose natural bent is toward the physical sciences and who may decide to enter the geophysical fold as a career. The other part will deal with those many men, geologists and engineers for the most part, who have drifted into exploration geophysics by one means or another, and whom it is necessary to train for geophysical work while they are occupied in their routine jobs. Here it may be in point to remark that most men in exploration geophysics at Present have been developed from precisely the latter group, and that the problem of training here is of great importance even though, in this paper, it will perforce occupy the secondary place. Training oF a Geophysicist The outstanding reason for the perplexing problem on the training of a geophysi-cist is that ideas differ on the answer to the question: "what is a geophysicistp" ln any of the scientific "specialties," like physics, for example, it is relatively simple to pigeonhole a man as being qualified to call himself a physicist. That appellation applied to an individual does not mean that he has mastered only the branches of intellectual endeavor usually associated under the broad name of "physics." we expect him also to have a more than mere acquaintance with mathematics and chemist~ and some understanding of most of the other sciences. But note this important point—we expect our physicist, whom we have chosen as an example, to be intelligently trained so that, if necessary, he can and will know how and where he can get the proper information on a subject in which he is not a specialist; he will know how to absorb that information and turn it to his uses. It seems to me that this is the outstanding characteristic of a man who can truly call himself a scientist: that he is a specialist in one of the broad branches of science in that he has enough training and discipline in the scientific approach so that, when called upon to do so, he can inteugently absorb knowledge from another bordering science (and all sciences not only border upon one another to some extent, but more often, overlap One another), and

Jan 1, 1946

By T. Sterry Hunt

At the meeting of the Institute in Easton, October, 1873,I made a communication on the Ore Knob copper mine, in Ashe County, North Carolina (Transactions, vol. ii, p. 123), in which I called attention to the chemical decomposition alike of the pyritous lode and the inclosing gneiss rock to a depth of 60 feet, by which the feldspar of the latter had been converted into clay, and the whole rock very much softened. Such a decomposition is well known to be almost universal in the crystalline rocks of the Appalachians south of the Potomac; and if it is only seen in rare and exceptional cases farther to the northward, this, as I have elsewhere pointed out, is due to the fact that the decomposition began and ended in the ages anterior to the drift period, and that the decayed portions which still remained were at that time removed from the surface, except in some localities which were protected from the emding agency. I have lately had an opportunity of studying a remarkable instance of this kind in an examination made last month for the corporators of the Hoosac Tunnel.* The locality is at the western base of Hoosac Mountain, the western slope of which rises rapidly 1300 feet above the town of North Adams, in Berkshire County, Massachusetts, itself 700 feet above the sea level. Through this mountain, as is well known, a tunnel for the Troy and Boston Railroad has lately been opened, a distance of 25,081 feet from east to west. The rock of the mountain consists of mica schist and micaceous gneiss, including in its western half a great mass of harder feldspathic and quartzose strata in part a granitoid gneiss, the strata for the most part dipping to the eastward with variable angles, but with occasional western dips, apparently due to inversion. The crystalline strata of the mountain crest and sides are in many places exposed, and present rounded surfaces, often deeply grooved and striated, but with no appearance of decay. At the western base of the mountain, however, the gneissic rock is in a state of complete decomposition, which was well displayed in opening the tunnel, which, for a distance of several hundred feet, was driven through highly inclined strata so much decomposed that they were excavated with pick and shovel, and without the aid of blast-

By H. E. Howe, A. A. Smith

The creep properties of lead alloys have been studied by a number of investigators but most of the work has been done on extruded material and the amount of data available on rolled alloys is surprisingly limited. Greenwood1 and his collaborators investigated various rolled commercial leads containing relatively small amounts of impurities, Phillips2 likewise studied rolled commercial leads, although he did include a few alloys— such as tellurium lead and one per cent antimonial lead. But as far as the authors are aware no data on the creep properties of so-called "hard leads"-—i.e., containing from 4 to 8 per cent antimony—have been published. In this paper some data are presented on a few antimonial lead alloys and compared with a copper-bearing lead. Preparation OF Specimens All the alloys used in this investigation were cast at a temperature of 400°C. into an open cast-iron mold preheated to Ioo°C., the resultant casting being % by I by 10 in. The copper-bearing alloy was cold-rolled by 10 per cent passes to a thickness of 0.100 in. Creep specimens 16 in. long were prepared by clamping the strips between wooden blocks and machining the edges of the strips parallel by means of a plane. Careful manipulation gave parallel specimens with no reduced section and with a minimum of distortion. The antimonial lead castings were hot-rolled in 10 per cent passes at a temperature of I50°C. to a thickness of 0.400 in., the heating being carried out in an electric oven after each pass through the rolls. After the castings had been broken down to 0.400 in., they were allowed to cool to room temperature and then cold-rolled to 0.100 in. with the usual Io per cent passes. Sufficient time was allowed after each pass for the strips to cool to room temperature. The apparatus and method of measuring strain have been adequately described in a previous paper3 and essentially the same practice was used in obtaining the present data. Time-extension curves for only two alloys are given, since these are typical of all. Figs. I and 2 show the time-extension Curves for the copper-bearing alloy A at 30°C. and loo°C., and Figs. 3 and 4 show

Jan 1, 1945

IDO not want to omit anything in which fire or its operation has a part, if I know or can tell it, and have already told you so many other useful, powerful, and ingenious effects (finally of powder and other' fire deadly and very injurious to all living things, indeed, composed for the destruction of those who possess it as well as those who do not) but I do not want the end of my writing to be in tragedy. Therefore I wished to tell you how, from these fires composed of forceful and horrible mate¬rials bringing harm and terror to men, a happy and pleasing effect is also produced and, instead of fleeing from it, the people willingly go to see it. Among others I remember that it was once customary to use these in Florence and in Siena, more than elsewhere. The chief feast day celebrated. by one of these cities is the day of the birth of Saint John, and the other is the Assumption of Our Lady, on the fifteenth of the month of August. In the morning they visit the shrines with great devotion and solemnity, displaying their pomp as much as possible, and later they hunt lions, wild bulls, untamed horses, and many other animals. In the same public squares there was also erected as a decoration an edifice fixed in the ground in the middle of this space, or hanging from a heavy rope crossing between the loftiest points of equal height that could be found in that place. This they have done and still do, and perhaps in time to come will continue to do when opportune. This structure was usually of wood; indeed it is necessary that the latticework of its construction be made only of this. It was covered and en¬larged by tying and fastening hay on top to bring it almost to completion and then papier-mâché was applied. [165v] The figures were first appropriately painted and made of a combination of vessels one above the other, developing various decorative figures in relief which should represent some fable or history and should not appear haphazardly made or without understanding. Now the master proceeded to arrange these figures in a composition according to his skill or art of design, and likewise planned

Jan 1, 1942

Discussion of the paper of E. L. deGolyer, to be presented at the Colorado meeting, September, 1918, and printed in Bulletin No. 137, May, 1918, pp. 987 to1000. J. A. UDDEN,* Austin, Tex. (written discussiont).-I have read Mr. E. L. deGolyer's paper on The Theory of Volcanic Origin of Salt. Domes, with a great deal of interest. It seems to me a very able summary and discussion of the various theories set forth to account for the origin of our salt domes on the coast. It has always appeared to me that what we need is more observations on the facts involved and I regret very much that so far we have not been able to devote much time to the study of our salt-dome fields on the coast in this State. One feature that I do not find mentioned in Mr. deGolyer's paper is the so-called "cap. rock" overlying the salt. The nature of this rock seems to vary from a coarsely crystalline limestone to a fine-grained limestone containing sand and in which the limestone seems to be intersticially introduced material. We should be prepared to accept, if necessary, "more than one theory. To my mind, the igneous theory and the artesian theory, if I may so call it, may very well both be true. The "squeeze" theory and the artesian .theory may,, it seems tome also, jointly explain the phenomena. Neither the volcanic nor the salt "squeeze" theory explains the presence of the cap rock. The latter certainly does not explain the extensive sulphur deposits which occur in association with the cap rock. Whichever additional theory will be found best to explain the salt-dome structures, when we shall know them better, it seems to me that the theory first advanced by R. T. Hill and later elaborated by G. D. Harris, is not likely to be entirely replaced. Whatever cause has first set into action an upward circulation of gases and liquids in our salt domes, it seems to me that to a gentle circulation of the kind postulated by their theory is to be ascribed the uppermost and the later phenomena in our salt domes on the coast, with which we are most familiar; such as the cap rock, the sulphur, and the gypsum and anhydrite deposits.

Jan 7, 1918

By Allan B. Bowman

Several years ago a wealthy Chinese business friend of mine purchased an interest in a pro- posed oil well to be drilled a great distance from his home. A few months later it came in as a producer and proved to be a huge success and materially added to his resources. I asked him why a man of his wealth should be so lucky in a venture outside his sphere of knowledge when most people of modest means never seemed to get ahead. His answer was, "Fat Hoy takes a chance." Even though this was his answer, I knew from my association with him that there were other tempering considerations which Mr. Hoy applied before making up his mind to enter any transaction. First, he was a cautious individual. He was also a great believer in details and insisted on knowing everything possible about a situation, and finally, he was what we call a very solid individual with good basic instincts and judgment. This philosophy of Mr. Hoy may be applied to most any business but especially to those engaged in a search for natural resources such as mining where great risks are involved. This article concerns events in the history and growth of Banner Mining Co., with which I have been associated for 27 years in capacities from mine surveyor to vice president. Mr. Hoy's philosophy has played a significant role in the exploration projects of this company over the years, but what is more important, the officers, directors, and controlling interests in Banner have been aggressive in their search for ore reserves.

Jan 6, 1963

By William L. Saunders

MANY members of the Institute, who participated in the visit made, during the Bethlehem meeting of February, 1906, to the shops of the Ingersoll-Rand Company, at Phillipsburg, N. J., inspected with interest the new Electric-Air drill, which the company had set up for the purpose of showing it in actual operation to American. mining engineers. At the request of the Secretary of the Institute, I promised at that time to prepare a paper for our Transactions, describing the construction and advantages of the machine. But such a paper would then necessarily have contained much that was only expected or claimed by the designers and manufacturers of the drill, and not yet incontrovertibly proved by varied and long-continued practice. However moderate such statements might have been, they would have given inevitably to the paper, to some extent at least, the air of a prospectus, rather than of a technical contribution. I therefore decided, with the Secretary's approval, to postpone the writing of the promised paper until it could set forth the results of adequate actual practice, as well as the latest details of construction, etc., based upon practical experience. That period has now arrived. The Electric-Air drill has been exhaustively tested in the field, under varied and arduous conditions and upon the hardest rocks. It is now fairly in the field; its merits and performances are matters of unimpeachable record, and its place among established competitors can be definitely determined. As a representative of the Ingersoll-Rand Co., as well as a member of the Institute, I may be permitted to add that my company, being largely interested in the manufacture of air-

Jan 9, 1907

By H. M. Howe

PART I. INTRODUCTORY. § 24. INTRODUCTION.-This paper discusses the chief existing data as to the temperature, in iron-carbon alloys, of Ae.3, the upper limit of the transformation range when in equilibrium, as distinguished from Ac3, the temperature at which the end of the transformation is noted in heating up, and from Ar3, that at which its beginning is noted in cooling down. The former is in fact carried above Ae3 and the latter below Ae3 by lag. I touch incidentally on the influence of manganese on Ae3 (§ 29, p. 1102). The sections, tables, and illustrations, are numbered consecutively with those in the accompanying papers by Howe and Levy on Determination of, the Position of Ae3 in Carbon-Iron Alloys, and by Burgess, Crowe, and Rawdon on Thermal and Microscopical Examination of Professor Howe's Standard Commercial Steels, to which the present paper forms a sequel. § 25. The contradictoriness of our present evidence is shown by grouping it together in Fig. 14. For instance, both Goerens and Meyer (Series 2) and Meuthen (Series 12) used practically stationary temperature, and thus reduced the influence of lag very greatly; yet Ae3 for 0.32 carbon steel according to the former investigators is 894°, but according to Meuthen it is at or below 770°, a discrepancy of 124° or more. In view of our ability to measure these high temperatures within a few degrees, the existence of such a discrepancy is as unwelcome as it seems needless. I attack the thankless task of bringing some order out of this chaos.

Jan 6, 1913

By R. Lagneborg

WhEN mechanical twins initiate cracking it has been proposed1 that the friction stress for dislocation motion, in the Cottrell criterion for brittle fracture2 should be replaced by the stress required to propagate a twin, ttp. TF is the fracture stress, d the grain diameter, ß a geometric constant, u shear modulus, and y the effective surface energy. Since TTp is likely to vary with grain size, it cannot be substituted by a constant in Eq. [I]. If an expression for the energy change caused by a twin in a stressed material could be obtained, it is in principle possible to compute the critical size of the twin, i.e., the size at which the system can decrease its energy spontaneously, as a function of applied stress, thus giving the stress required to just barely propagate the twin, i.e., TTP. Consider a circular twin disc with a radius r and having a lenticular cross section, Fig. 1. Twin dislocations3 of strength b exist in the twin boundary parallel to the twin plane, one loop on each atomic plane. Assume that the total numbers of loops, n, can be replaced by one circular loop of a multiple dislocation, nb with a radius r. The energy change of the system, AW, due to such a twin in an applied stress field can then be calculated: The first term is the total twin surface energy, the second the elastic energy due to the twin dislocations, and the third the energy released by the twin in the applied stress field. yt is the twin boundary energy, r, the radius of the dislocation core, and T the applied

Jan 1, 1968

W. P. Blake, Shullsburg, Wis.: I desire to express my admiration of Prof. Posepny's memoir, and particularly of the charming manner and spirit of the introduction. With respect to his mention of the ore-deposits of Missouri and Wisconsin, reference may be made to my paper presented at this meeting (Trans., xxii., 621)) showing the existence of dislocations and breaks in the bedding, and their apparent close relation with the localization of the ore-deposits as claimed by Dr. James G. Percival, and also so claimed by Dr. Jenney in his paper before us (Trans., xxii., 171). I have in my paper given reasons for believing that the zinc- and lead-ores in the strata above the compact Trenton limestones were formed by lateral secretion and concentration from above downwards, substantially as shown by Prof. J. D. Whitney, and not by the ascent of solutions through the fissures, as Prof. Posepny (p. 304) seems inclined to believe. In regard to the contemporaneity of the ore and the rocks, and in favor of a later introduction of ore through fault-fissures, Prof. Posepny (p. 310) cites the influence of these fissures. In my paper, already referred to, I have endeavored to show how faults may have influenced the deposition of ore without being themselves channels for the flow of mineral solutions, and how they may have caused the contemporaneous formation of metallic sulphides from sea-water in the body of a forming rock; the faulting fissure being formed at an early period in the foundation rocks, and probably continuing to be a plane of break and movement in the deposits of later formation.

Jan 1, 1894

By Henry M. Howe

In discussing the classification of iron to-day, we are to leave out of consideration the general division into non-malleable or cast iron and malleable iron, as to the adequacy of which no question has been raised; and to confine ourselves to the subdivisions of malleable iron. This has been classified, according to the extent to which the properties imparted by carbon are present (viz., resilience, hardness,strength, and, above all, the capacity for being hardened by sudden cooling from a high temperature), into (1) wrought iron which cannot be hardened, and (2) steel which can be hardened; and this classification I shall, for briefness, term the carbon classification. Until within a few years all authorities, both metallurgical and general, have concurred in explicitly recognizing the carbon-given qualities, and preeminently the capacity for being hardened, as the essential qualities of steel; this is laid down with clearness by every writer on the subject. For several years this old classification has not been sufficient to meet all our needs, since the genius of Bessemer, Siemens, and, I may add, Holley, has produced wrought iron which has been perfectly melted, and thus freed from certain mechanical adhering impurities. This causes what we call homogeneousness for want of a better word, and gives rise to many important qualities which the old wrought iron had not; qualities universally recognized, though not readily described. I shall, for briefness, style them the fusion qualities, and a classification based on them, a fusion classification. These qualities render the new product so vastly superior, for most purposes, to the wrought iron formerly known, that it is neces-

By M. J. Taffanel

I AM very much impressed by this manifestation of international brotherhood; the mining engineers on both sides of the ocean have similar subjects to deal with, meet with the same difficulties, expose themselves sometimes to similar dangers; they are like companions in arms in the battle fought by mankind in order to subjugate the natural forces and to draw profit therefrom. There is no other field where this fraternity must manifest itself more actively than in the studies pursued with a view to improving the safety of mines and to rendering impossible in the future these mining disasters, which every year claim hundreds of victims. These are very difficult problems, the solution of which requires numerous and laborious experiments accompanied by very arduous scientific investigations; it is extremely desirable that the various mining countries, which have undertaken to solve these difficult problems, should unite their efforts in order to succeed as soon as possible and as well as possible. This idea has been fully grasped by your Bureau of Mines, which has brought me to Pittsburg; the daily exchange of views with the distinguished chief of-the mine investigation division, George S. Rice, and with his excellent collaborators, the comparison of the results obtained at Lievin and Bruceton, the checking of these results by means of new tests, the profound study of the measurements, diagrams, measuring and laboratory apparatus, the cooperative investigation of new apparatus, or the preparation of new investigations, are, I hope, of such a nature as to bring about great progress. I think that it will be interesting to you to know what has been done in France along this line.

Jan 9, 1914

JOHN.B. HASTINGS, Los Angeles, Cal. (written discussion).-This paper reminds me that when I had an option on a Nevada mine, where the only orebodies assayed $4 gold, I went to San Francisco to learn the cost of putting broken ore in a 25-ft, vein on the mine cars, and sought Mr. Alfred Wartenweiler, who said "There is not a mine in California that can tell what it costs to move ore in the stopes." When building small mills in the mountains, and with only 30 or 40 employees, by entering in a log at night the work performed by each man, I have been able to plot the costs with the accuracy shown in this paper, and very good discipline it is. Cost of new construction and repairs is carefully kept by most companies, and is compiled after completion; probably the outlay of labor and material in pieces of work sufficiently important to call for blueprints is estimated beforehand, but numberless odd jobs of construction and repairs are so itemized. . Might it not be worth while, at a large plant, to have these smaller daily tasks described in advance in a central repair office, and then let inspectors look over the job, report time and material needed, and enter it in sufficient detail in proper ledgers, the men then being sent to accomplish it, and reporting when finished? The forecasts would soon be made quickly and correctly and would give the head mechanic, carpenter, and electrician easy supervision of their men, and the results could be seen at a glance by the managers.

Jan 4, 1918

By Young C. Kim, Francis Martino, Ish Chopra

For the past two and one-half years, various emission control strategies were jointly developed by the University of Arizona and the Homer City Owners to com- ply with the clean air requirements at its Homer City Power Plant. Some of the available options for the SO2 emission control by the Homer City Owners were:l)cleaning of run-of-mine coal,2) scheduling of mining operations at its captive mines, 3) blending the captive mine coal with externally purchased low sulfur coa1,and 4) placing a partial FGD system. This paper describes two specific emission control strategies developed and implemented. These are: 1) production scheduling at the mining face to minimize sulfur variability, and 2) external purchasing of low sulfur coal for further blending. The main objective of this paper is to share our experiences on implementing the developed strategies. This paper emphasizesthe need for proper mine planning on a short-term basis, if the power plant is to meet the desired objective.

Jan 1, 1983

By Joachim J. Hauser

Experiments on latent hardening were peyformed by compressing single crystals along a direction perpendicular to the tension axis. The slope and length of easy glide in the tension test were found to depend only on prior deformation in the same slip plane. Prior deformation on a different slip plane changes the stress level of the resulting stress-strain curve. The yield points appearing upon reloading after prior extension and unloading were related to the end of easy glide. SEVERAL researchers have studied the latent hardening due to deformation of a crystal by slip on a slip System after prior deformation. These experiments can be divided into those in which the prior deformation was on the same plane as the subsequent and those in which the two deformation processes were in different planes. In the former category are the experiments of Buckley and Entwistle,1 Parker and washburn,2 and Haasen and Kelly.3 The latter case has not been studied systematically; it was the main purpose of this investigation to produce this type of latent hardening and explain the results in terms of the existing theories of work hardening. In general, tension producing slip on a certain slip system can be preceded by tension, transverse compression or longitudinal compression, each with predictable dislocation movement and intersection. The intersection of dislocations can lead to glissile or sessile jogs, Cottrell-Lomer locks and other sessile dislocations. The effect on the stress-strain curve could depend on which combination of the former mechanisms is operating. Haasen and Kelly3 have studied the yield points which occur in aluminum and nickel single crystals upon reloading after prior unloading in a tension experiment. They attributed this effect to the anchoring of dislocations occurring during unloading. As Cottrell and stokes4 have shown that dislocations cutting through the "forest" could only lead to reversible changes, they attributed the anchoring to the formation of sessile dislocations during unloading. However, different kinds of sessile dislocations could be formed during unloading, and it was the purpose of this experiment to determine whether Cottrell-Lomer locks are responsible for the yield effect and for the end of easy glide. The case where a longitudinal compression is followed by tension along the same axis is commonly referred to as a Bauschinger test. This type of effect was studied by Buckley and Entwistle1 on aluminum single crystals and by Parker and washburn2 on zinc single crystals. In such a test, the tension and the compression activate the same slip plane with opposite slip directions. The use of sideways compression in the present experiments permits the activation of different types of slip systems and the study of their effect on the easy glide region and on the transition between the elastic and easy glide region. The theory of seeger5 for the flow stress in fee materials is applied to explain the latent hardening. EXPERTMENTAL PROCEDURE All the single crystals used in this investigation had an axial orientation close to <210>, called the "0.5" orientation. This is the orientation for which the tensile axis is 45 deg from both the slip plane and the slip direction. The single crystals were grown from the melt under a helium atmosphere using milled graphite boats,=at a rate of 8.6 mm per min. The silver used in the experiment was 99.98 pct pure. The single crystals had a square cross section about 0.9 by 0.9 cm and a length of 14 cm. The orientation of the specimen was determined within ±2 deg by the Laue back-reflection method. The specimens were annealed at 940&apos; ± 2°C in a helium atmosphere for 24 hr and then furnace cooled over a period of 7 hr. The specimens were electropolished in a solution of 9 pct KCN in water. The specimens were tested in a soft-type tensile machine (the load is prescribed) up to 3 pct strain. The stress was increased continuously at approximately 30 g per mm2 per min. The strain was measured over a 5 cm gage length with a mechanical extensometer employing an optical lever. The strain and stress were measured with accuracies of i 2 X 10-5 and ± 2 g per mm2, respectively. The remainder of the stress-strain curve up to 20 pct strain was obtained in a hard-type tensile machine (the strain rate is prescribed). The strain and the stress were measured in that machine with an accuracy of ±2 pct. The compression tests were performed in the hard-type machine using accurately machined steel blocks without lubrication. The blocks were used so as to apply a uniform compression over a length of 13 cm. The strains were measured on the hard-type machine and with a micrometer.

Jan 1, 1962

Charles H. Morgan, Worcester, Mass. (communication to the Secretary): In connection with Mr. Douglas&apos;s mention of the continuous charcoal kiln used at Kopparberg, some further data concerning this important invention may be of interest. Before giving these, however, I will say a word or two concerning other features of Swedish practice. In 1894 I spent two days at Soderfers with Mr. Tom Bergendal, the manager of the works, and was specially interested in the gas-producers and wood-drying kiln, illustrated in the paper contributed to our Transactions by Mr. Odelstjerna in that year.* The wood-drying kiln is, however, quite different in design and construction from Ljungberg&apos;s charcoal kiln. In the summer of 1894 it was discovered that by placing the gas-producer as close as possible to the open-hearth furnace, and working the producer hot, ordinary weather-dried wood, still containing a considerable percentage of moisture, could be used to advantage in the melting-furnace. Hence, the dryingkiln was needed for wet wood only. One of the iron-works of the Udeholm Go. was the first to adopt the Lundin saw-dust gas-producer and condenser, enabling them to make gas from saw-dust containing 45 per cent. of moisture, and convey the gas from the condenser through wooden pipes to the Siemens steel-melting furnace.† This sawdust gas gave very satisfactory results in iron-works; but the proprietors experienced much trouble by reason of the pollution of rivers by the tar-water from the condenser. On my visit, in 1894,I found that the Udeholm Co. had put in for their steel-melting furnaces the same wood-gas producers

Jan 1, 1899

By J. D. Lubahn, R. P. Carreker, J. G. Leschen

The formation of slip bands in crystalline solids undergoing plastic deformation has recently been treated as a problem of nu-cleation and growth.&apos; A simplified theory was developed and shown to be qualitatively consistent with certain experimental observations reported in the literature, such as the frequent failure of slip bands to traverse the entire crystal, the effect of specimen diameter and temperature on the yield stress, and the occurrence of incubation periods in the deformation of suddenly loaded crystals. The theory further predicts the appearance of transients in the rate of strain of a crystal when the applied stress is suddenly changed from one constant value to another. A transient consists of a discontinuous change in the strain rate followed by a gradual approach to a steady-state value. Such transient behavior apparently has not been recognized in previous experimental work. The preliminary experiments reported in the present paper were undertaken to confirm the existence of the predicted transients and thus to determine whether a more detailed treatment of the nucleation theory of slip might be theoretically and experimentally fruitful. Experimental Procedure A simple creep apparatus was assembled as shown in Fig I. Very little insulation was used on the furnace in order to facilitate rapid changes of temperature. Temperature was measured with a thermometer placed in the center of the furnace and was controlled by adjusting the Variac setting. The specimens were cold-headed in split-cylinder grips. The strain was measured as total elongation by a dial gauge sensitive to I/I0,000-in movement of the weight pan. Since the specimen gauge lengths were

Jan 1, 1949

Prior to any detailed discussion, I&apos;d like to say that Dr. Aplan has made direct hits on two important considerations: 1) The most demanding need in Fine Coal research is to develop improved methods of sulfur reduction. 2) The areas of particle (impurity) liberation and froth flotation hold real near-term promise as techniques for improved sulfur removal. Digressing for a moment, I thin kwe can all remember the time when the biggest problem facing coal research was simply defined - "No money!" In the mid 70&apos;s we suddenly found ourselves dealing with a product worth five to seven times the value it carried in the mid60&apos;s. All of a sudden, we&apos;re talking about a high-profile, high- value commodity. The coal industry still hasn&apos;t made the complete psychological adjustment - especially in the operating areas (prep plants included). We have a valuable material at hand which is, in&apos; many cases still being processed as though it were a two or three dollar per ton item. Simply put, I think that while the industry has made some major strides during this transition, a stronger commitment of attitude (and finances) needs to be made toward deeper definition of beneficiation work. Back to specifics - Dr. Aplan has really highlighted three areas where strong research efforts are needed. 1) Liberation processes - not limited to mechanical comminution - must be more fully studied.The industry certainly needs a better handle on value returned (improved ability to beneficiate) for dollars spent on improved liberation. 2) Flotation processes probably hold the most promise for near- term improvement in fine coal beneficiation technology. Dr. Aplan’s.

Jan 1, 1979

THOMAS T. READ, Palmerton, Pa. (communication to the Secretary*). -It is much to he regretted that in presenting a further discussion of these deposits, first described by myself&apos; and later discussed by C. M. Weld,2 Mr. Wang bas not made a more complete presentation of the evidence on which he bases his conclusions as to their origin. Mr. Weld said in his paper that his visit was confined to a few hours, that he saw only one of the several exposures, and that he took away no samples for further study. My own visit was brief, and for another purpose than the study of the geological features of &apos;the deposits, so the fact that Mr. Weld described as a hornblende-granite the rock which I described as a "dark gray syenitic rock," and which Mr. Wang identifies as a hornblende-syenite, seems of no great importance, since this rock is generally decomposed along the contact, presumably the only place in which Mr. Weld observed it. Later in the same paper (p. 31), Mr. Weld says that his opinion is that the magnetite of the deposits is primary, but Mr. Wang makes no mention of this in stating his own conclusion to the same effect. When Mr. Weld&apos;s paper appeared, I did not discuss it, because, although I considered the evidence- that he brought forward to support his belief that the magnetite is primary too slender to support the hypothesis, my own evidence to the contrary was equally tenuous. .The opportunities for observation and study open to Mr. Wang must have provided him with

Jan 6, 1917

By W. J. Helfrich, R. A. Dodd

Binary aluminum solid-solution alloys containing various amounts of silver, magnesium, and zinc were prepared by careful directional solidification, and the hydrostatic and X-ray densities were compared. With the exception of the Al(Ag) alloys, the X-ray densities were consistently greater than the hydrostatic measurements, in agreement with earlier observations by Ellwood. In contrast to Ell-wood&apos;s interpretation in terms of vacant lattice sites associated with Brillouin zone effects, a tentative explanation based on the existence of solidification microshrinkage was favored. This hypothesis was confirmed by an examination of Al(Zn) alloys prepared by vapor diffusion of zinc into aluminum. The hydrostatic and X-ray densities were now in very close agreement, and it was concluded that the filling of Brillouin zones in aluminum solid-solution alloys does not necessarily result in the formation of defect structures containing an excess of vacant lattice sites. ThE existence of defect structures of the vacancy type in alloys in which the excess vacancies have an electronic rather than a thermal or mechanical, and so forth, origin is well recognized. Examples of incomplete lattices of this type are to be found in the Ni-Al,1-3 Fe-Ni-A1,4 c~-Ni-Al,5 Fe-Cu-Al,= and Co-A17 systems. These defect structures are of a special kind in that the intermediate phases possess an ordered atomic arrangement or superlattice, and in some instances the vacancy concentration may be unusually large, e.g., at 45.25 at. pet Ni in NiA1, approximately 8.8 pet of the lattice sites are unoccupied. Ellwood8-10 has reported similar defect structures in the aluminum solid solution alloys of the Al-Zn and A1-Mg systems and in alloys of the Au-Ni system." In Al(Zn) the (apparent) vacancy concentration rose, somewhat irregularly, to a maximum of about 2 pet vacant sites at 25 at. pet Zn, while in Al(Mg) the (apparent) vacancy concentration increased continuously to 1.7 pet at 15 at. pet Mg. An explanation in terms of Brillouin zone overlap was attempted, although Pearson12 has pointed out the difficulty of reconciling the observations with zone theory. However, the possibility of the effect being caused by the Fermi surface just touching a plane of energy discontinuity inside a prominent Brillouin zone has, in general, been accepted. In fact, Massal-ski13 has interpreted Ellwood&apos;s8 observations as confirmation of Leigh&apos;s14 theoretically predicted zone overlap occurring at approximately 2.67 electrons per atom. Unfortunately, Massalski was apparently unaware that Ellwood9 had revised his earlier results considerably, and the revised data did not confirm Leigh&apos;s analysis. Ellwood&apos;s clata were reexamined by the present authors who noted a possible correlation between the percentage defects as a function of alloy composition and the temperature interval of solidification measured from the respective equilibrium diagrams. This suggested an explanation in terms of shrinkage porosity rather than vacant lattice sites, and pointed to the desirability of reexamining appropriate alloy systems using: both Ellwood&apos;s method of specimen preparation (casting followed by wrought fabrication) and alternativ&apos;e methods, i.e., diffusion, which might be expected to minimize, or even completely obviate, microporosity. ALLOY PREPARATION 1) Cast Allolys and Aluminum Single Crystals. Al(Ag), Al(Mg;l, and Al(Zn) alloys of various compositions up to 20 at. pet silver, 13.5 at. pet mg, and 30 at. pet Zn were prepared by melting under helium and casting into graphite molds. In the first two systems, the maximum alloying addition was quite close to the limit of solid solubility, but the possibility of transformation to a&apos; during quenching somewhat restricted the suitable Al(Zn) composition range. The alloys were prepared from high-purity aluminum, a lot analysis showing 0.002 wt pet Cu, 0.002 wt pet Fe, and 99.996 wt pet A1 by difference. The silver, magnesium, and zinc were of 99.99+, 99.98+, and 99.998 wt pet respectively. Each composition was analyzed chemically. The as-cast ingots measured 7/16 in. diam and 5 in. length. One in. was removed from the top of the ingot, and the bottom 3 in. was machined to 0.275 in. diam; a point was also machined on the smaller diameter end. The remainder of the original ingot served as a top riser during subsequent remelting and controlled solidification. The machined ingots were now remelted using a Bridgman soft-mold technique to ensure directional solidification and, therefore, a minimum of micro-shrinkage. Alumina powder was used as mold material contained in an alundum thimble, and this crucible was placed in a helium-filled Vycor tube. The assembly was lowered through a suitable temperature gradient at approximately 0.5 in. min-l, and the risered portion of the casting was subsequently removed by sawing.

Jan 1, 1962