Search Documents

DAVID WHITE,* Washington, D. C.-This paper is very timely since the Philippine Islands are presumably open to the enterprise of the American driller, whereas much of the territory in that part of the world is closed to us. The United States has ambitious plans for the operation of a great merchant marine, which is to be oil burning in the main, and it takes but a glance at the world map to see the strategic advantage of oil supplies in the Philippines for such marine operations. It is a little difficult to understand why more attention has not been given to the Philippines, in spite of the difficulties attending development in these islands. A number of American oil companies are, I believe, at the present moment taking an interest in the possibilities of the Philippines. Important factors in the formulation of opinion regarding the importance of the oil deposits of the Philippines, as brought out by Mr. Pratt,1 are the point of view and the breadth of experience of the examining geologist. The average oil geologist, whose experience has been mainly in the Appalachian region, the Mid-continent, or Louisiana, or possibly even in California, on seeing the narrowness of the basins, the closeness of the folding, and the presence of igneous rocks here and there, would be likely to draw unfavorable conclusions as to the possibilities of the Philippine Islands. Geologists visiting that region should be familiar with the geological conditions of oil occurrence in Japan, Formosa, the East Indies, or in the Baku district, and their conclusions should be formulated with the knowledge and understanding of the occurrence of oil in those regions rather than in the United States.

Jan 8, 1920

By C. H. P. Lupis, R. Hocine, G. Bernard

The necessary and sufficient conditions for the stability of a multicomponent phase with respect to infinitesinzal fluctuations are derived and transformed to be written in terms of activity coeffcients and mole fractions rather than in terms of the customary second deritlatives of the free energy. NECESSARY conditions for the stability of a multi-component system were derived by Gibbs as early as 1876.' However, as the usefulness of these conditions is greatly enhanced by the simplicity of their translation in terms of functions of common usage, the present contribution establishes these conditions in terms of activities or activity coefficients-and mole fractions. It was shown in another article2 that not only may these conditions be used for the prediction of the appearance of new phases, but they may also provide a check on the orders of magnitude of the interaction coefficients involved. "Spinodal" decomposition is said to occur when, at constant temperature and pressure, the system is unstable with respect to infinitesimal fluctuations in composition. As a result, the "phases" which appear may be attained through continuous changes in the system rather than discontinuous ones, and, consequently, the free energy of these phases may be described by a unique continuous free-energy function. For a binary system, the familiar curve of Fig. 1 illustrates the case we wish to extend to a multicom-ponent system. The conditions to be written pertain to the decomposition of a system of n moles into moles of phase moles of phase v, ...hen moles of phase 9, where the phases a, ...v, ...9 are—at least initially-arbitrarily close in composition to that of the original phase. Each A, is positive and since the total number of moles n in the system remains constant: Each phase v contains hv(nl +dnY) moles of component (I), ...xV(ni +dny) of component + dnk) moles of component (m). The total number of moles ni in the system remaining also constant, it is clear that:

Jan 1, 1968

By W. R. Ingalls

In reviewing the history of the metallurgy of zinc, I shall pass hastily over what is only of antiquarian interest. That has been excellently treated by Dr. Bernhard Neumann in "Die Metalle" (1904) and has been described briefly in my "Production and Properties of Zinc" (1902), in my "Lead and Zinc in the United States " (1908), and in other metallurgical works of more or less the same date. In this present monograph, I have it in mind to confine myself mainly to technical practice, especially to that of the last 75 years, prior to which period advance was slow and of no great moment. The ancients made brass by the cementation process, i.e., embedding copper in a mixture of calamine and carbon and heating, whereby zinc oxide was reduced and zinc was vaporized and combined with the copper. Zinc was isolated by some of the alchemists, who named it and knew something of its properties, but made no use of it. Long before then, however, zinc was produced in India. Later it was produced in southern China. Possibly the Chinese obtained their knowledge from India. The Chinese in remote places still produce small quantities of zinc. I have seen photographs of their furnaces; or pots, for they hardly deserve the dignity of being called furnaces. I imagine that they are the same that were used centuries ago, for I cannot conceive of anything more primitive. Anyway, it is certain that the idea of a commercial production of zinc in Europe was imported from the Orient, where the metal was known in commerce as Speauter and Spiauter, whence speltrum and finally our term spelter. Tutanego and Tuteneague are other old names. Dr. Isaac Lawson went to China about 1730, expressly to discover the method of its production. What connection there was between Isaac Lawson and John Champion we do not know, but the latter obtained in 1739 a patent for a process of distillation downward and at some time between 1740 and 1743 erected a works at Bristol and actually began the manufacture of spelter. A production of 200 tons per annum is mentioned. In about the year 1766, Rishop Watson visited the Champion works and saw the process in operation, which previously had been

Jan 1, 1937

By J. Kent Smith

THE object of this investigation was to ascertain the effect of varying percentages of beryllium upon pure copper and the properties of the resultant alloys in their softest condition, the effect of heat hardening on them, and the extents to which these properties could be augmented by different combinations of heat hardening and cold rolling. The data compiled in this paper represent partial results of continuing work done by the writer during the years 1930 and 1931, which was a continuation of the unpublished ground work incepted in the laboratory of the Beryllium Corporation of America by H. B. Pulsifer in the year 1926. A short bibliography on beryllium alloys is appended to this paper. It has, of course, long been known that copper subjected to cold work is hardened and strengthened to a considerable extent, furthermore it had been qualitatively noted in previous experiments that copper-beryllium alloys seemed to take on hardness and strength as the result of cold work at a greater rate even than does plain copper. It was decided therefore to endeavor quantitatively to determine such rate of increase, as also the relative increases by combinations of cold working and heat hardening. The results are summarized in Tables 3, 4 and 5. A preliminary series of experiments had indicated that by an exposure to the heat of 575° F. for 2 1/2 hr. age-hardening of a 2.50 per cent beryllium-copper alloy took place. Slab ingots of nine different beryllium-copper alloys were prepared under identical conditions by means of the addition of a previously prepared 12.5 per cent beryllium-copper alloy to well melted and deoxidized pure copper. The ingots were then reduced by hot rolling to 12 gage (about 0.080 in.). These strips were heated to 1450° F. and quenched in cold water, and thus brought to their softest condition. (See Table 1.) Strips were next "precipitation-hardened" by reheating to a definite temperature. Similar strips to those itemized in Table 1 (which had been quenched from 1450° F.) were reheated for varying periods of time at 575° F. The hardness figures show that a metastable condition, of which the range of stability is dependent entirely upon time at the given temperature, begins to be noted in copper samples containing as little as 0.85 per cent beryllium. It is extremely noticeable in samples containing

Jan 1, 1932

One of the engineering proposals in the last Congress which was of interest to engineers was the soldiers' land settlement plan proposed by Secretary Lane, under which returned soldiers, sailors and marines would be employed on construction work in the reclamation of swamp and arid lands and would thereafter be given preference in the selection and settlement of those lands. This bill failed in the fillibuster at the end of the session. It is likely that some sort of a plan for soldiers' settlement will come before the next Congress. A new bill has been written up for introduction at the next session which proposes an "infiltration method" of buying improved farms in established communities for' the soldiers' settlement purpose, under the authority and direction of the Farm Loan Board. The contrast of this bill to the one recommended by Secretary Lane is of vital importance to engineers at this time; first, because of the broad engineering improvement program that the latter bill proposes as against no engineering improvement under the infiltration plan; secondly, the community settlement plan of Secretary Lane means improvement of waste lands requiring much engineering work.

Jan 7, 1919

By Robert L. Dean, Michael Hoch, Samuel M. Wolosin, Chung K. Hwu

The general shape of the 1450°C isotherm of the Ti-TiO-ZrO2-Zr region was evaluated from the surrounding binary phase diagrams and from thermo-dynamic data on the metal-oxygen binaries. The phase boundaries were accurately determined using X-ray and metallographic techniques. At 1450°C the system shows a large bcc ß field, which extends from the two metal-oxygen binary systems as a Gaussian error function, and is stable up to 30 at. pct 0 when Ti and Zr are present in equal amounts. At higher O Concentrations, the ß field is in equilibrium with t-ZrO . The following four regions, with three solid phases, are present: two a ß t-ZrO,, a TW t-ZrO,, and TiO t-ZrO2 c-ZrO2. On cooling the ß phase transforms into the a phase, going through the w transition phase. The isotherm at 1500°C for the region TiO-TiO,-ZrO, was obtained by using X-ray diffraction. At 1500°C a large c-ZrOz region is present as well as a large two-phase field, Ti0 c-ZrO,. The following regions, with three solid phases in equilibrium, were found These regions are relatively small. The solidus and liquidus relationships were determined by observing samples suspended in a tungsten crucible by means of a fine tungsten wire and heated in vacuum. Eleven univariant points were found. C-ZrO, decomposes through a peritectic reaction into liquid t-ZrO2. The activities of Ti and TiO in the TiO t-ZrOz and in the two a ß t-ZrO regions were measured using the Knudsen effusion method. In the a TiO t-ZrO, region the activities of Ti and Ti are the same, as in the a — Ti TiO binary. In the two a t-ZrO, regions, the Ti activity is high and the Ti0 activity very low, although all phases present contain at least 30 at. pct 0. This indicates a short-range order in the solid phases, Zr atoms being preferentially surrounded by 0. 1 HE system Ti-Zr-0 is of interest because of the wide ranges of solid solubility exhibited by the boundary systems; as titanium and zirconium both belong to the same group of the periodic table, large single-phase regions should occur within the system, with a great variation of properties (as the composition changes within the single-phase region). Furthermore, the possibility of modifying ZrO, to make it a more usable refractory by the addition of other metals makes this system also of interest. Because of the high affinity of titanium and zirconium for oxygen, the oxygen partial pressure is very low at all compositions; thus, there exists a ternary metal-metal-oxygen system in which the oxygen pressure is not an important variable, so long as it is low enough. When a sample is heated in vacuum to a temperature high enough for vaporization to occur, the vapor phase will consist of metal and metal-oxide gas, the oxygen concentration being very low. The phase relationships in the surrounding binary systems have already been reported in the literature; therefore, the study of the ternary diagram

Jan 1, 1962

By Albert Hayes

FOUR mines at Wabana, on Bell Island in Concep-tion Bay, Newfoundland, produced 1,209,777 tons of ore in 1927, and it is expected that the produc-tion will be larger in 1928. The ore is a stratified oolitic hematite of sedimentary origin. Three workable beds and many thin beds occur in a thickness of 400 ft. of interbedded sandstones and shales. It is not profitable under present conditions to mine extensively in ore beds less than 4 ft. thick. The iron ore beds outcrop on the small island and are inclined northward more steeply, than the slope of the ocean bottom. The mine work-ings follow the bedded ore below the sea bottom, No. 3 Mine extending about 2 miles north of the island. At this point there is a cover of 1500 ft. of rock and 600 ft. of ocean water. It is impracticable to operate drills in the ocean to prove the extent of the submarine orebody in advance, and diamond drilling from the mine workings is the only method of exploration. Bell Island has been settled for a long time and a monument at Cupids, near Brigus at the head of Conception Bay, commemor-ates the tercentenary of a settlement there in 1611 by Captain Guy of England. was one of the chief ports of Newfoundland for deep sea fishing and doubtless many a captain wondered about the red rocks as he sailed past. The famous geologist, J. B. Jukes, records seeing a bright red sandstone 8 ft. thick on the northwest side of Bell Island during a visit in 1842, but he evident ly did not try to land on that rocky coast to get a sample. The iron ore is plainly visible in the high cliffs along the coast of the island, as bright brown layers interbedded with gray and white sandstones and dark shales. The heavy red rock was used by the fisher-men as anchor weights for fish nets and small boats, but its real value, so the story goes, was discovered by a merchant in Saint John,

Jan 8, 1928

By H. A. Wriedt

At 500°C (932°F) the range of y' iron nitride is from 5. 77 + 0.03 wt pct N (in coexistence with a iron) to 5.88 * 0.03 wt pct N (in coexistence with E iron nitride). Stoichiometric "Fe,N" (5.900 wt pct N) is near the upper extreme of possible compositiom. The depe-dence of nitrogen activity (expressed as pnh,/Ph,) on nitrogen content is described satisfactorily by a "Langmuir" isotherm: At even the highest nitrogen concentrations, less than 0.18 pct of' the nitrogen atoms present are impositions of disorder. Past investigations1-4 of the Fe-N system have left only details of the thermodynamic behavior of the y' nitride, "Fe,N9', to be studied. The present investigation was made to establish more precisely than hitherto the limits of composition and the relation between composition and nitrogen activity at 500°C. EXPERIMENTAL TECHNIQUE The compositions of nitrides in equilibrium with various NH, + Hz mixtures at 500°C were determined from the weights gained by 0.02-in.-thick (4.0 to 4.5 g) strips of purified iron* when the nitrides were formed A description of the gas generation and furnace system has been published.5 Cracking and blistering during conversion of the original solid iron at 550°C injected considerable porosity into the strips without causing their disintegration. The time for complete conversion was significantly lowered by periodically reducing partly nitrided specimens in hydrogen and then reexposing them to the nitriding gas. Gas mixtures producing single-phase were used in the equilibrations at 500°C. Equilibrium was regarded as existing when the specimen weight was not detect-ably affected by further exposure to the same conditions. The gas compositions and nitrogen activities at which y' transformed to a iron (lower activity limit) and to E iron nitride (upper activity limit) were redetermined during the investigation. A specimen was equilibrated in an NH, + Hz mixture at 500°C and then exposed to a s1ightly different gas. When equi- librium had been reestablished the gas was again changed slightly. At each stage of this repeated process, while the specimen was reacting with the gas, the variation of its weight with time was observed. The onset of phase transition was marked by an abrupt change in the amount and rate of weight gain or loss. The specimens were weighed outside the furnace, in air and at room temperature, on a balance with 0.05 mg precision. When it was found that the specimens were oxidizing at a significant rate during the weighing, a series of timed weighings was made with each specimen, starting 1 min after its exposure to air. RESULTS AND ANALYSIS The gain in specimen weight from oxidation during weighing was linear in the logarithm of time between 1 min and about 2 hr, Fig. 1, later becoming linear in the cube root of time. In the logarithmic period, nitride specimens oxidized two to three times as fast as

Jan 1, 1970

By W. M. Peirce

Commencing in 1922, each year a lecture has been presented to the Institute of Metals Division at this February meeting. The range of subjects has been very- broad. Some speakers have dealt with the most advanced work in the very heart of the science of physical metallurgy. Others have stimulated our imaginations by discussing the most recent progress in related fields of science. Others have told us of the latest art, which is at any moment of greater practical importance than the latest science, of metals. I feel that this broad precedent in the choice of subjects will justify my choosing to talk about some of the prosaic details of how, during the last generation, industry has effectively organized research to accelerate progress in our own and all other fields of science and related art. A number of years ago I visited one of this country's well-known research laboratories and had the pleasure of chatting for a few minutes with its equally well-known director. Being particularly interested at the time in the organization problems connected with industrial research, I broached that subject. My host stated in effect that he didn't believe in organized research. He was, of course, resorting to a rhetorical hyperbole. to pain: out the danger of overorganization which can so easily drift into regimentation and destroy individual initiative. Actually nearly all of us, much as we cherish our personal freedom of action, believe in organization because the history of progress in every field of human activity has been a history of men learning to work together, to cooperate, to create an efficient division of labor. We use organization to achieve this coordination. At the same time our form of organization must not stifle individual initiative or it will prove a deterrent rather than an aid to accomplishment. Research, too, must be organized for greatest achievement but especial skill and care are perhaps needed to avoid stifling the initiative of the individual workers. I have, of course, followed with keen interest and much benefit the vast amount . that has been said and written on this subject in the past twenty years but I still find new stimulation in discussions with my good friends working in this field. It is my hope that this discussion may serve a like purpose. It would be ungracious not to make due acknowledgment to the many able contributors to this particular phase of human progress, but their very number and the great volume of their writing makes it impossible to trace to any one individual a particular significant and valuable idea. I shall content myself therefore with this general acknowledgment and with acknowledgment of the specific debt that every research man owes to those who have so ably kept before the public, and in particular before industrial executives, the place of research in the modern scheme of things' Because of the legitimate publicity thus given to research, the day is past when any

Jan 1, 1944

By W. M. Peirce

Commencing in 1922, each year a lecture has been presented to the Institute of Metals Division at this February meeting. The range of subjects has been very- broad. Some speakers have dealt with the most advanced work in the very heart of the science of physical metallurgy. Others have stimulated our imaginations by discussing the most recent progress in related fields of science. Others have told us of the latest art, which is at any moment of greater practical importance than the latest science, of metals. I feel that this broad precedent in the choice of subjects will justify my choosing to talk about some of the prosaic details of how, during the last generation, industry has effectively organized research to accelerate progress in our own and all other fields of science and related art. A number of years ago I visited one of this country's well-known research laboratories and had the pleasure of chatting for a few minutes with its equally well-known director. Being particularly interested at the time in the organization problems connected with industrial research, I broached that subject. My host stated in effect that he didn't believe in organized research. He was, of course, resorting to a rhetorical hyperbole. to pain: out the danger of overorganization which can so easily drift into regimentation and destroy individual initiative. Actually nearly all of us, much as we cherish our personal freedom of action, believe in organization because the history of progress in every field of human activity has been a history of men learning to work together, to cooperate, to create an efficient division of labor. We use organization to achieve this coordination. At the same time our form of organization must not stifle individual initiative or it will prove a deterrent rather than an aid to accomplishment. Research, too, must be organized for greatest achievement but especial skill and care are perhaps needed to avoid stifling the initiative of the individual workers. I have, of course, followed with keen interest and much benefit the vast amount . that has been said and written on this subject in the past twenty years but I still find new stimulation in discussions with my good friends working in this field. It is my hope that this discussion may serve a like purpose. It would be ungracious not to make due acknowledgment to the many able contributors to this particular phase of human progress, but their very number and the great volume of their writing makes it impossible to trace to any one individual a particular significant and valuable idea. I shall content myself therefore with this general acknowledgment and with acknowledgment of the specific debt that every research man owes to those who have so ably kept before the public, and in particular before industrial executives, the place of research in the modern scheme of things' Because of the legitimate publicity thus given to research, the day is past when any

Jan 1, 1944

By C. H. G. Bushell

The author maintains that selectivity in flotation depends in part on differences in rates of flotation. The rate of flotation should be directly proportional to the frequency of particle-bubble collisions. In this paper, it is suggested that floatable particles of the mineral must be distinguished from nonfloatable particles. Success in flotation is entirely a matter of selectivity. All minerals can be made to float. The problem is to make one mineral float and leave the others in the tails. For a typical ore, with all minerals naturally hydro-philic, a collector which is adsorbed by only one mineral and not at all by the others would give perfect separations. The hydrophobic, collector-coated mineral would separate cleanly from the remaining minerals. In practice, no such highly specific reagents are known. All standard collectors adsorb on most minerals to some extent, and selectivity then becomes a matter of extent of adsorption rather than adsorption on some minerals and not on others. Flotation is therefore a compromise process: if enough reagent is used to float all the desired mineral, the concentrate will be low grade; conversely, high grade concentrates can be attained only at low recovery. With many minerals coated with collector to varying degrees, selectivity appears to depend in part on each mineral floating at a different rate. The study of flotation kinetics is therefore a basic requirement to quantitative understanding of the process. REVIEW OF PREVIOUS THEORIES Before a particle enters the froth it must strike a bubble and adhere to it. Flotation rate will therefore depend on the number of particle-bubble collisions

Jan 1, 1962

By L. B. Slichter

It has been estimated that rock exposures in most mining districts aggregate less than 1 per cent. of the total surface area.1 Conclusions concerning the hidden 99 per cent. necessarily have been based on knowledge of only a small fraction of the surface, and from this limited information the geologist has been obliged to deduce the approximate and general nature of the underlying formations. In the search for ore it is necessary to supplement this general picture with greater detail. Fairly accurate knowledge of relatively small zones is required. This knowledge is carefully sought in many different ways—detailed interpretations of geological history, the tracing of float, the use of test pits, of trenching, of drilling, and of other methods. Practical ingenuity, scientific brilliance, great perseverance and patience, and the expenditure of large sums of money have all been a part of this search. The problem of exploring beneath cover with economy, and of obtaining essential information which this cover hides, is obviously a difficult one. It is also a very important one, for geologist's inform us that already the story of the 1 per cent. exposed outcrops has been largely read.V here remains the nearly virgin field comprised in the hidden 99 per cent.: and the importance of this zone is bound to increase continually. In recent years, the problems connected with the exploration of this "99 per cent. zone" have attracted a constantly enlarging group of investigators and at present greater efforts than ever before are being made to resolve them. This work, in it's various special aspects, has enlisted, beside geologists, the cooperative efforts of chemists, physicists, and mathematicians. The progress made in this development should be kept before those directing explorations in order that due advantage may be taken of a changing situation. My subject concerns certain aspects of one of the older physical methods of exploration, the magnetic method. This method is familiar in principle to most of us, arid because of its age., is especially suitable for

Jan 1, 1929

By A. L. Mincher, W. F. Sheely

Mechanical properties of columbium have been studied over the temperature range of -196 to 1093oC. The decreased strengthening influence of cold-work at temperatures below ambient has been interpreted in terms of the Peierls-Nabarro effect. Maxima in the rate of strain hardening observed during tensile testing in the range 250-600°C. have been correlated with interstitial impurities to indicate the temperature ranges at which carbon, oxygen, and nitrogen, respectively, are responsible for strain aging. THE growing need for structural materials for use above the useful service temperatures of the iron-, nickel-, or cobalt-base alloys has caused the refractory metals to be considered as potential engineering materials. These metals, which include columbium, tantalum, molybdenum, and tungsten, are called refractory because the lowest melting point among them,that of columbium, is about 1000°C higher than the average melting temperatures of conventional high-temperature alloys. They are all body-centered cubic transition metals and, as such, their mechanical properties have basic characteristics which distinguish them from the face-centered cubic metals. For example, all show a much steeper rise in strength with decreasing temperature below room temperature than do the face-centered cubic metals, and their mechanical properties are strongly influenced by interstitially dissolved impurities. In order that these new metals may be used efficiently, it is necessary that their characteristics of behavior be fully known. In this paper, the mechanical properties of columbium will be examined over a wide range of temperatures. In particular, the influences of cold-work and individual species of interstitial impurity atoms on mechanical properties will be described, and basic mechanisms which may control the observed characteristics will be explored. EXPERIMENTAL The material used in this investigation was Union Carbide Metals Co. columbium roundels consolidated to four 4-in. diam ingots, three by consumable-electrode arc melting and one ingot by electron beam melting. Impurity contents of the ingots and methods of ingot conversion and treatment are summarized in Table I. The only metallic impurity occurring in any significant quantity was tantalum at about 0.1 pct. Iron, silicon, titanium, and zirconium were each less than 0.015 pct; boron was 1 ppm or less. This should have no appreciable influence on properties. The electron beam melted material, being the purest, will be used as the basis for comparison in the discussions to follow. Tensile tests were conducted from-196 to 1093oC, on both cold-worked and fully recrystallized arc-melted and electron-beam melted columbium using standard 1/4-in. diam, 1-in. long gage length test specimens. A strain-rate of 0.005 in. per in. per min was employed until the 0.2 pct yield strength was achieved and then the strain-rate was increased to 0.05 in. per in. per min for the balance of the test. Samples were protected in an inert atmosphere at tests above 300°C. The tensile properties obtained on the electron-beam melted columbium, E, in both the cold-swaged and recrystallized conditions are given in Fig. 1. The yield strength data of Dyson, et al.,' obtained on recrystallized electron beam melted columbium and the tensile strength data reported by Tottle2 on powder metallurgy columbium are included in Fig. 1. The material used by Tottle had been purified by vacuum sintering. There is excellent agreement between Dyson's data and those obtained in the present investigation. The tensile strengths obtained by Tottle were slightly greater than those obtained in this investigation on electron-beam melted columbium but varied with temperature in a similar manner. Tottle's data showed a maximum in tensile strength near 500°C, as did our data on electron-beam melted material, and also showed a small maximum at 300°C. The significance of these maxima will become evident later in the discussion. The tensile properties of cold-swaged and recrys-tallized arc melted columbium are plotted in Fig. 2. It was found that the properties of the recrystallized arc-melted columbium from all three heats showed very close agreement except at temperatures between about 500" and 800°C. A reason for this range of disagreement will be suggested in the discussion. The generally good agreement, however, attests to the ability of cold-working and subsequent recrystal-lization to erase the effects of the three different primary breakdown procedures and to produce nearly equivalent structures in the samples derived from the three different heats. wesse13 reported tensile data on columbium having interstitial impurity contents between those of the

Jan 1, 1962

By W. D. Robertson, W. L. Phillips Jr.

Stress-strain curves were obtained for single crystals of alpha brass in tension and in direct shear. Specimens were strained various amounts in a given slip direction, unloaded, and immediately strained in a second slip direction 60°, 120°, or 180&apos; from the original slip direction. Crystals strained in tension and direct shear had comparable critical resolved shear stresses and stress-strain curves. The density of slip lines in direct shear and in tension was essentially the same. The stress-strain curves obtained in shear were independent of initial orientation, choice of {111 } slip plane, choice of <110> slip direction, prior annealing temperature, and rate of cooling after annealing. There was no recovery after annealing for 4 hr at room temperature or 200°C; recovery was observed after 4 hr at 400°C. The crystals showed no asterism and mechanical properties were completely recoverable up to 20 pct strain. It was found that there is a barrier to slip in all latent close-packed directions, and that the magnitude of these barriers, evaluated at 3 pct strain, is proportional to prior strain and independent of the choice of latent direction in the {111} plane. The formation of Cottrell-Lomer barriers is discussed as a possible explanation for the hardening of the latent systems. AN idealized concept of plastic deformation indicates that a single crystal should yield at some stress that is dependent on crystal perfection and it should then continue to deform plastically by the process of "easy glide," which is characterized by a linear stress-strain curve and a low coefficient, ds/dE, of work-hardening. Hexagonal metal crystals generally conform to this ideal concept of laminar flow. In face-centered cubic metals the range of easy glide is always restricted in magnitude and it is strongly dependent on orientation, composition, crystal size, shape, surface preparation, and temperature. Since one of the principal differences between the two crystal systems, both of which deform by slip on close-packed planes, is the existence of secondary (latent) slip planes in the face-centered cubic crystals, it has been proposed that the transition from easy glide to turbulent flow, characterized by rapid linear hardening, is due to slip on secondary planes intersecting the primary plane.&apos;-.; However, the characteristic differences between individual face-centered cubic metals remain to be explained; in particular, it is not clear why the range of easy glide should vary so greatly in different metals and alloys similarly oriented for single slip. An investigation and comparison of different metals with respect to latent hardening on the primary slip plane should provide some of the information required to specify the necessary and sufficient conditions governing the transition from easy glide to turbulent flow. But, in order to accomplish this purpose, plastic strain must be produced by simple shear in a chosen plane and in a predetermined direction by some form of directed shear apparatus, the results of which must be correlated with the corresponding tension experiments. Two such experiments have been performed previously with zinc and with aluminum. Edwards, Washburn, and Parker" and Edwards and Washburn7 found that the strain-hardening coefficients in two latent directions in the basal plane of zinc were the same as in the primary direction. However, to initiate and propagate slip in either the [2110] or the [1210] direction, following primary slip in the [1l20] direction, it was necessary to increase the stress above that required to continue slip in the primary direction; when the direction of shear was reversed 180 deg plastic strain began at a much lower stress than that required to initiate slip in the original direction and the stress to propagate slip in the reverse direction was lower than the stress to continue slip in the forward direction, indicating a permanent loss of strain-hardening. Rohm and Kochendorfer observed softening in aluminum for all latent close-packed planes and directions. They also found that the critical resolved shear stress obtained from their direct shear apparatus was 50 pct lower than the value obtained from conventional tension tests, that the stress-strain curve was linear at 50 pct plastic strain, and that slip lines were not visible at strains less than 30 pct. At present it is uncertain whether these diverse results correspond to real differences in work-hardening characteristics of the close-packed planes of aluminum and zinc or to differences in experimental technique. In view of Read&apos;s analysis &apos;" of the stress distribution in the experimental arrangement of Rohm and Kochendorfer, there is some reason to question the significance of the latter results. In order to resolve this problem it is necessary to re-valuate the direct-shear technique and either repeat the previous measurements or investigate a third system. The latter choice seemed most likely to produce significant results with respect to work-hardening, and accordingly, it was decided to examine the hardening characteristics of the latent slip directions in alpha-brass. The choice of alpha-brass was dictated by the fact that easy glide is more extensive in this alloy than in any other face-centered cubic metal or alloy and, presumably, more nearly like the idealized hexagonal system. Experimental Procedure Crystals were made in graphite by the Bridge-man method in the form of cylinders, 11/2 in. diam and 8 to 9 in. long. Material for the crystals was 70/30 brass containing the following impurities:

Jan 1, 1959

By L. T. Lloyd, H. H. Chiswik

The operative deformation elements in a-uranium single crystals under compression at room temperature have been determined as a function of the compression directions. The deformation mechanisms noted may be arranged with respect to their frequency of occurrence and ease of operation in the following order: 1 — (010)-[I001 slip, 2—{130} twinning, 3—{~172} twinning, and 4bunder special conditions of stress application, kinking, cross-slip, {.-176) twinning, and (011) slip. The composition planes of the (172) and (176) systems were found to be irrational. Cross-slip was shown to be associated with the major (010) slip system, coupled with localized interaction of slip on the (001) planes. The mechanism of kinking was found to be similar to that observed in other metals in that it occurred chiefly when the compression direction was, nearly parallel to the principal slip direction [loo] and was associated with a lattice rotation about an axis contained in the slip plane and normal to the slip direction: the [001] in the uranium lattice. The resolved critical shear stress for slip on the (010)-[100] system was found to be 0.34 kg per mm2 In a single test it was shown that under compression in suitable directions twinning on the (130) also occurs at 600°C. DEFORMATION mechanisms of large grained polycrystalline orthorhombic a-uranium have been studied by Cahn.1 A major slip system identified as the (010) with a probable [loo] slip direction and a minor slip system on the (110) planes were reported; the slip direction of the minor system was not determined. The twinning systems that were identified experimentally included the (130) and the irrational (172) composition planes; observations of other traces which were not as frequent and which did not lend themselves to positive experimental identification led Cahn to postulate on the basis of indirect evidence that twinning also occurred on (112) and (121) planes. In addition to the foregoing slip and twinning mechanisms, Cahn also observed kinking and cross-slip in conjunction with the major (010) system; the cooperative cross-slip plane was not identified. The availability of single crystals to the present authors has enabled them to check these results, particularly with reference to the doubtful mechanisms and the preference of operation of any one mechanism in relation to the direction of stress application. The tests were confined to compression only, primarily because of experimental limitations imposed by the size and shape of the available crystals. The tests were performed at room temperature except for one crystal compressed at 600°C. The compression directions were chosen to obtain a representative coverage of one quadrant of the stereo-graphic projection. To test the existence of some of the deformation elements that were reported by Cahn, but were not found in the present study, several additional crystals were compressed in specifically chosen directions considered most ideal for their operation. Experimental Techniques The single crystals were obtained by the grain coarsening technique described by Fisher? They grinding and polishing on rotating laps, with final surface preparation performed in a H3PO4-HNO3 electropolishing bath. A typical crystal readied for compression is shown in Fig. 1; their dimensions were rather small and depended upon the testing direction. Crystals isolated for compression in a direction close to the [010] axis, which lay roughly parallel to the longitudinal axis of the polycrystalline rod, were about 3 to 4 mm long and 5 mm2 in cross-section, while those prepared for compression in other directions were smaller. Most of the crystals were free from twin markings and showed no evidence of Laue asterism. Several crystals, however, contained twin traces prior to compression; these were identified prior to compression so as to clearly distinguish them from those initiated during deformation. The origin of the twin markings prior to deformation may be ascribed to two sources: thermal stresses and specimen handling during isolation and preparation. Two other types of imperfections in the crystals should be mentioned: inclusions, which were probably oxides or carbides. and three of the crystals contained a small number of spherical included grains (<0.01 mm diam), which were remnants of unabsorbed grains from the coarsening treatment. The volume represented by these imperfections was small, and their presence presented no difficulties in the interpretation of the macrodeformation processes during subsequent compression. Two compression fixtures were employed: crystals A, B, C, E, and G were compressed in a hand-operated screw-driven jig whose compression platens were designed to minimize axial rotation;

Jan 1, 1956

By Roy Lindgren

SINCE the year 1643, when the first blast furnace in America for treating iron ore was built at Saugus, Mass., out of mica schist quarried in the neighboring district, the procurement of a suitable refractory for furnace lining has been a problem of concern to the operators of furnaces. The stacks built of mica schist continued to smelt iron ore until about 1836, when, according to F. H. Norton, the first firebrick were produced1, at Queens Run, Pa. Other writers speak of brick having been molded and burned in Massachusetts about the year 1834. In 1841, Andrew Russell began to produce medium refractory plastic clay brick near East Liverpool, Ohio, that were used for lining blast furnaces1. The well-known Kentucky clay-producing district was not opened up until the year 1871, but since then it has produced a large percentage of the linings for iron blast furnaces. While some strides have been made by the refractories industry during the 100 years that have passed since the first firebrick were produced, it has been only during the last two decades that any real progress has been made towards bettering the product, even though the method of production had improved. Perhaps the fault lies with the user of the brick rather than with the producer, for not sooner demanding a supe-rior product. During the past 15 years the tonnage produced per lining has increased from 500,000 gross tons to 1,000,000 gross tons, and now some furnaces are producing 1,600,000 gross tons and better on a single lining. It is true that enlarged capacity of furnaces and improved practice have accounted for some of this increase in tonnage, nevertheless better quality in firebrick must be given credit for its share. However, we are not yet ready to say that we have reached a maximum life of furnace lining. We believe that a better product can be produced and that the refractories industries of America will, through their extensive research depart-

Jan 1, 1937

By Robert Glass Cleland

BECAUSE of the country&apos;s vast mineral resources, Alexander Von Humboldt, the great German scientist who visited Mexico, or the Kingdom of New Spain, a hundred and fifty years ago, very aptly called that country the "Treasure Chest of the World." During the three centuries of Spanish rule, mining was the principal industry of the kingdom, the largest contributor to the country&apos;s prosperity, the chief common denominator in Mexican economic life. Public revenues and private fortunes, employment and markets, agriculture and trade, charities and churches, the incentive for frontier settlement and exploration, and the funds for outfitting the expedition of colonizer and conquistador-all were dependent upon the streams of precious metals that flowed century after century from the mines of Guanajuato, Zacatecas, Real del Monte, San Luis Potosi, and scores of other minería that lay scattered everywhere throughout the land. Sonora, one of the oldest and most renowned of the frontier provinces of New Spain, had been the scene of a hundred rich strikes, sudden stampedes, and widely heralded bonanzas long before the famous and frenzied Gold Rush

Jan 1, 1952

By Pierre Hines

THE. Owyhee Tunnels in eastern Oregon were started in the early part of 1930, and were completed early in 1932, with the excep-tion of the Magoffin contract. One tunnel is a large water tun-nel, and the other is a small water tunnel; each is approximately tour miles long. Modern equipment was used to full advantage, and remarkably fast time was made during the driving period. The ,J. F. Shea Co., con-tractors, of Portland, Oregon, have broken established records in the smaller tunnel. Their methods are described in detail. The time of a complete round has been reduced by intelligent handling of mechanical shoveling, and this article records some of the useful facts developed. Charles A. Shea (president of the J. F. Shea Co., and secretary of The Six Companies, Inc.) not only granted permission to publish this article, but placed the company&apos;s complete daily reports at the writer&apos;s disposal. These reports were made out to conform with previous records upon important tunnel work, and enable a comparison to be made of actual averages, rather than ideal cycles, or representative cycles. Gilbert Shea, present superintendent, has been helpful with time, criticisms, and corrections of the information presented. Morton S. Boss, superintendent during the first 15 months of the tunnel work, gave many hours of his time during two visits lasting over two weeks. The whole staff of the J. F. Shea Co. has given encouragement and assistance.

Jan 1, 1933

By Samuel Thomas

The specimen of anthracite coal which I hold in my hand, insignificant as it may appear to the casual observer, speaks volumes to me and to the initiated, as it suggests and represents the entire evolution of the use of anthracite coal in the manufacture of pig-iron, the growth and development of which it is my purpose to review here to-day. During our recent visit to the Mountain Copper Co.&apos;s works at Keswiek, I picked up this piece of coal from a pile of anthracite lying in the yard, asked Mr. Edwards, the manager, a countryman of mine, where it came from, and, to my surprise and delight, discovered that it had been brought all the way from Wales, and had come out of the identical vein which my father opened near Yniscedwin, about eighty years ago. I had no idea, before this incident, of contributing to the already full and complete programme of the day; but, being requested by our distinguished President and Secretary to do so, I consented to relate here the story which this remarkable find naturally brought back to my mind.

Jan 1, 1900

By J. B. Dilworth

The purpose of this paper is, first, to give a general account of a little-known coal-district of SE. Kentucky, its topography, drainage, and mineral resourcee, for those who may be interested in its economic development; and secondly, so to describe the geologic features of the field as to furnish available data to those engaged on the broader problems of Appalachian coal-geology. The data from which the major portion of the paper has been prepared were obtained, in professional investigations for private individuals and corporations, within the last decade. The area under review, defined by a heavy line on the map, Fig. 1, lies between Little Black and Pine mountains, and extends from Harlan on the west to a N-S. line crossing Looney creek 3 miles from its mouth on the east. This area can be divided for description into a Western and an Eastern Division. The character of investigatioil pursued in the Western Division, below Fugitt creek, was very different from that employed in the Eastern. In the former, only a rapid reconnois-sance was attempted: such coal-openings as had been made by prospectors or by citizens in obtaining fuel were visited, their

Jan 1, 1913