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By John S. Brown

AT opposite ends of a mineralized belt of northeast-southwest trend, and ten miles apart, are the Edwards and Balmat zinc minas, in St. Lawrence County, New York, west of the Adirondacks. The principal town is Gouverneur, fifteen miles west of Edwards, eight miles northwest of Balmat, and the area is often referred to as the Gouverneur district. (See Fig. 1.) At various times the district has been noted for its hematite mines, pyrite mines, and marble quarries, all now abandoned. At present, in addition to zinc, it is the country's largest source of industrial talc. A short distance to the east important magnetite mines are operating. Geologically the district lies at the southern margin of the Canadian shield, where this great expanse of Pre-Cambrian igneous and metamorphic rocks merges into the foothills of the Adirondacks. The rock formations in approximate order of areal extent and importance are as follows:

Jan 1, 1947

By Ralph W. M. Lai, D. W. Fuerstenau

This paper presents the results of a study of the principles which control the distribution of ultrafine particles between an oil phase and an aqueous phase. Alkyl sulfonates were used to control the wettability of fine alumina particles and to stabilize the water-isooctane emulsion system in the extraction process. The effects of sulfonate chain length, sulfonate adsorption, pH, and oil-water ratio on the recovery of solids in the oil phase were investigated. Higher extraction was found under conditions which yield higher hydrophobicity and large interfacial area of the oil-water emulsion. Today there is considerable interest in developing methods for the recovery of fine particles from disseminated ores. One such method might be the extraction of fine particulate solids from aqueous suspensions into an oil phase, and one example of a successful industrial process based on oil-water distribution phenomena is the emulsion flotation process used in concentrating manganese ore.' The oil agglomeration process of Farnand, Smith, and Puddington has been suggested for concentrating tin ore. Patents 3-4 for oil flotation processes extend back to that of William Haynes in 1860. The basis of all these processes is directly related to the stabilization of emulsions with solid particles. The first extensive study of oil-water emulsions stabilized by finely divided solids was made by Pickering. Later, Briggs,6 weston, 7 Chessman and King,8 and Leja and Schulman9 experimentally demonstrated how solid particles control water-oil and oil-water systems. Hildebrand10 suggested that fine particles can stabilize an emulsion because the fine particles are partially wettable by both oil and water, that is, that the contact angle must be finite. Takakuwa and Takamori 11 recently applied emulsion inversion to the study of collector adsorption in flotation systems. At the Royal School of Mines, Shergold and Mellgren12 are currently carrying out a comprehensive study of the extraction of fine particles into an organic liquid phase. In the present study of the liquid extraction or oil flotation of ultrafine particles, the recovery of hydro-philic alumina particles of 0.1-µ average diameter was determined after separating an isooctane-water mixture (emulsion) into its two phases. Alkyl sulfonates of different chain lengths were used to change the wettability of the alumina and to effect emulsifi-cation of the oil-water mixture. The effects of the oil-water volume ratio, sulfonate adsorption, and pH on the recovery of the fine particles were investigated. Since the surface charge on an oxide such as alumina is determined by the adsorption or interaction of H+ and OH- with the surface, pH control is extremely important. Furthermore, since the zero point of charge (zpc) of alumina13-14 occurs at pH 9 to 9.4, major adsorption effects with anionic collectors in these systems will occur below pH 9. The results of the foregoing investigation are discussed in terms of the recovery of the fine particles, the oil-water ratio, contact angles, surface tension, the adsorption of sulfonate onto the solid surface, and the emulsifica-tion of oil. MATERIALS AND EXPERIMENTAL METHODS Materials: The particulate solid used in all the experiments was Linde "A" alumina, a high-purity, readily available form of a-alumina. The surface area of the alumina, as evaluated from measurements of stearic acid adsorption from benzene, was 14.5 sq m per gm, based on a value of 20.5 sq Å for the cross-sectional area of stearic acid.13 All aqueous solutions were prepared from triply distilled conductivity water. Other materials included high-purity crystals of sodium alkyl sulfonates, isooctane, and, for pH adjustments, reagent grade hydrochloric acid and sodium hydroxide-Because sulfonic acids are strong acids, they are

Jan 1, 1969

By A. H. Daane, J. J. Hanak, F. H. Spedding

IN the study of the rare earths at the authors' laboratory, methods have been devised for preparing pure rare earths and many of their properties'- have been determined. Very little information is found in the literature on the properties of europium metal, which is the scarcest of the naturally occurring rare earths. Since we have recently prepared europium in appreciable quantities, we are in a position to describe the method of preparation and some of the properties of this metal. Metallic europium was first prepared by Klemm and Bommera who heated a mixture of potassium and EuC1, in vacuo, and obtained a mixture of europium metal and KC1. Trombe4 electrolyzed a molten salt bath containing NaC1, KC1 and EuC1, and collected the europium in a molten cadmium electrode as a cadmium alloy. The cadmium was subsequently removed by distillation but the properties of the residue indicate that pure europium was not obtained. McCoy attempted to prepare europium by distilling mercury from europium amalgam, but the stability of the Eu-Hg intermetallic compounds prevented a complete separation of the two elements. The preparation of very pure europium was suggested by previous work in this laboratory1,4 in which ytterbium and samarium were prepared by heating the respective sesquioxides with lanthanum metal turnings to 1450°C in vacuo and distilling ytterbium and samarium from the mixtures. Subsequently, small test experiments showed that europium also could be prepared by this method. A more detailed version of this method was used in the work described in this paper. Klemm and Bommer3 found by X-ray analysis that the metal had a body-centered cubic (bcc) structure with a lattice constant a, = 4.582 ± 0.00A (converted from kX units), with a bulk density of 5.30 g per cu cm. They found europium to be weakly ferromagnetic. Spedding, et al,7 found a,, to be 4.606 ± 0.001A. Barrett' showed that the bcc structure persists throughout the temperature range 5 to 3000K with a, at 5, 78, and 300°K being 4.551 ± 0.003, 4.551 ± 0.004 and 4.577 ± 0.001A, respectively. Trombe1 described europium as being iron gray, malleable, about as hard as neodymium and not attacked by cold water. He estimated the melting point to be between 1100 and 1200°C. Previous work in this laboratory indicated that the pure metal corrodes rapidly in air and reacts with cold

Jan 1, 1959

By Shrikant Lele

INTRINSIC and extrinsic stacking faults may be formed in fcc structures by similar processes with bounding S-and D-Shockley partial dislocations respectively.' The only difference between these two dislocations is that the side on which the fault lies is reversed. The number of nearest and next nearest neighbors of atoms is identical for the two faults, but that of next next nearest neighbors is different. Thus, the energies associated with intrinsic and extrinsic faults may be expected to be different but of the same order of magnitude. An extrinsic fault can be constructed from two intrinsic faults on adjacent close-packed planes. This suggests that the extrinsic fault energy is higher than the intrinsic fault energy. It is, therefore, surprising that extrinsic faults have not been detected in X-ray studies2 of deformed alloys of low stacking fault energy. These have, however, been observed in cerium3 by X-ray diffractometry and in Au-4.8 at. pct Sn4 and Cu-16.6 at. pct A15 alloys by transmission electron microscopy.

Jan 1, 1968

By C. Alstetter, V. Kerlins

By using alloys with subzero Ms temperatures, this investigation demonstrates that the amount of decomposition of martensite during the quench from austenite may be considerable and especially so in specimens of large cross -sections and high Ms temperatures. The activation energy for decomposition as measured dilutometrically is PREVTOUS investigations of the initial decomposition of Fe-C system martensite have invariably been limited to alloys having M, temperatures above a function of the amount of transformation which has taken place. The amount of transformation is a linear finction of log time. A correction term to the activation energy is derived for dilatometric measurements in which no end-point of the transformation is detected. room temperature. In such alloys the martensite is tempered during the quench to an extent dictated by the quench rate and temperature of formation. This tempering, called quench-tempering, Q-tempering, self-tempering, or auto-tempering, although frequently acknowledged, has not been studied or treated quantitatively. To do so one should obtain absolutely untempered martensite and study its decomposition. This as-formed martensite could be obtained either by extremely rapid quenching, requiring very thin specimens, or by lowering the martensite formation temperature range. The second alternative is more effective, because

Jan 1, 1963

By D. G. Russell

A simple method has been developed with which flowing bottom-hole pressure data from two-rate flow tests in oil or gas wells can be analyzed to estimate the formation permeability, skin factor and average reservoir pressure. The required pressure data are obtained by observation of the transient bottom-hole pressure behavior after the stabilized producing rate of the well is changed to another, higher or lower, rate. The new method yields the same information as a conventional pressure buildup analysis, but eliminates the need for closing in the well. The analysis of a two-rate flow test is of the same degree of difficulty and requires about the same engineering time for application as a conventional pressure buildup analysrs. The extended closed-in periods experienced with conventional buildups because of long, low-rate afterproduc-tion periods are eliminated by fIow tests. Other anomalous pressure buildup effects, such as "humping" due to weli-bore phase segregation, can be successfully eliminated with the new method. Generally, flow tests of about 24 hours' duration run with conventional pressure measurement equipment are sufficient for interpretation purposes. Field testing of the two-rate flow test method has established that it is a reliable and economical method which can be used in many instances to complement or even replace conventional pressure buildup methods. INTRODUCTION The principal method for estimating formation permeability and well damage, or skin factor, in a producing oil or gas well is the analysis of shut-in bottom-hole pressure buildup data.' This familiar method has been used quite successfully by reservoir engineers for many years. It is based on the solution of the radial flow equation for constant rate conditions, and requires that the well be closed in for a sufficient period of time to obtain a clearly defined linear portion on the plot of observed t + ?t bottomhole pressure vs log t + ?/?t(where At is shut-in A? time, and t is producing time to the instant of shut-in). From the slope of the plot and other normally obtainable data, the permeability, skin factor, and reservoir pressure at infinite shut-in time (if the reservoir were infinite) can be estimated. Over the years several drawbacks have become apparent in the use of conventional shut-in pressure buildups for determining permeability and skin factor. The conventional pressure buildup interpretation theory assumes that a well is closed in at the sand face and that no production into the well occurs after shut-in. In practice, of course, the well is closed in at the surface, and inflow into the well continues until the well fills sufficiently to transmit the effect of closing in to the formation. This adjustment period is commonly referred to as the "after-production" portion of the pressure buildup. In the tight reservoirs, long, low-rate after-production periods frequently occur, and the well must be shut in for several days or, in some instances, even weeks to obtain an interpretable buildup curve.' Obviously, such long shut-in times can cause loss in current income, both from reduced oil production and from the fact that personnel and pressure measurement equipment are occupied with a single well for too long a time. In other cases, even long shut-in periods do not seem to be of much aid in obtaining an interpretable buildup." If there is considerable phase redistribution (liquid fallout or bubble rise) after a well is shut in, then curves with no interpretable portion are often obtained during the buildup. In addition to instances in which wellbore effects cause trouble, there are also cases in which the major objection to use of the closed-in pressure buildup is simply the fact that the well must be shut in. When there is no proration and when the well has limited producing capacity. closing in the well means loss of income. From the foregoing discussion it is apparent that it ib desirable to have an alternative method of obtaining the same information as that derived from a conventional buildup without the need of closing in the well. One possible solution which has been offered for this problem is the use of a bottom-hole shut-in tool' which isolates the major portion of the flow string from the formation face during the buildup. In this paper an alternative method which is frequently successful in avoiding wellbore effects and which does not require the use of special equipment is presented. A new, simple method has been developed with which the flowing bottom-hole pressure data from flow tests in oil or gas wells can be used to estimate permeability, skin factor and the average reservoir pressure. The required pressure data are obtained by observation of the transient bottom-hole pressure behavior after the stabilized production rate of the well is changed to another, higher or lower rate. The need for closing in the well is eliminated, and pressure measurement periods of only 18 to 24 hours arc usually sufficient, even in tight reservoirs. Thus, the new

COAL is perennially -a subject of major interest at. Pittsburgh, but during the week of Nov. 19 to 24 it was especially to the fore because nearly two thousand persons gathered to take part in the second of the international conferences organized by President Baker of the Carnegie Institute. From the opening session on Monday morning when those attending were welcomed by President Baker and T. P. Gaylord, president of the Chamber of Commerce of Pittsburgh, until the party returned from the Clairton coke ovens on Saturday. afternoon, there was something going on all the time, and usually three sessions were in progress at once.

Jan 1, 1928

By F. P. Haver, M. M. Wong

The Federal Bureau of Mines has developed a leach= electrolysis method for recovering lead from galena (PbS). Flotation concentrate is leached with ferric chloride (FeCl3) solution to obtain lead chloride (PbC12) and elemental sulfur, PbS + 2FeC13 -+ PbC12 + 2FeC12 + Sº. Over 99% of the P~S in the condentrate is converted to PbC12. The leach solution, composed of brine (NaC1) and FeC13, dissolves the PbC12 as it is formed, leaving a residue of elemental sulfur plus gangue. Very pure PbC12 (>99.9%).is crystallized from the leach filtrate on cool- ing and is subsequently electrolyzed in a fused-salt bath to obtain molten lead metal (>99.9% Pb). Spent leach solution (FeC12) is regenerated for further use by reaction with the chlorine obtained in the electrolysis of lead chloride, and other values, such as Ag, Cu, Zn, and Sº, are recovered by additional treatments of the leach solution and leach residue. This paper discusses results and conditions of the leaching and electrolysis operations.

Jan 1, 1976

By H. H. Stoek

Danville, the county seat of Montour county, Pa., was one of the earliest and best-known centers of the iron intlustry in the State. It is situated on the north bank of the north branch of the Sosquehanna river, twelve miles east of the confluence of the north and west branches of that river at Northurnberlttnd. The ore-belt, extending for a distance of twelve miles along the north bank, has been developed in a number of places, but nowhere so extensively as in the immediate vicinity of Danville. Hence, a description of the mines in that locality will suffice, as typical of the workings of the entire section. Geology. The Montour ridge consists of an anticlinal fold extending from the source of Wapwollopen creek on the east to the west branch of the Susquehanna, which it reaches at the mouth of Chilisquaque creek. According to the reports of the First Geological Survey of Pennsylvania, the length of the ridge is nearly twenty-seven miles, with an average breadth of three-fourths of a mile, and a maximum elevation of six hundred feet in the vicinity of Danville, where it also attains its greatest width. Just north of Danville the Mahoning creek cuts through it, exposing the iron-ore on the hill-side, where advantage has been taken of this to work the beds on the southern slope of the ridge by means of drifts. The sections given in Fig. 1 are taken from the reports of the First Geological Survey of Pennsylvania, made in 1858, by H. D Rogers, whose description of the Moatour ridge was so complete and accurate that the entire report was reprinted as an appendix to Vol. G 7 of the Second Geological Survey. The approximate crosssection shows that near Danville the top of the ridge is of Clinton vol, xx.—24

Jan 1, 1892

By W. H. Craigue

THE scope of this article covers only the mathematical principles involved in discounting to present worth future expected profits and it is believed answers definitely two questions, which were raised at a recent meeting of the Committee on Methods of Valuing Coal Properties, as follows: 1. The accumulative effect of carrying charges on the value of coal mines showing definitely the number of years beyond which the coal may not be mined at a profit and subsequent to which the possession of any unmined coal will be a liability rather than an asset. 2. The effect on the valuation of coal mines, in the presence of the carrying charges described in question 1, of an increase in plant capacity and production. In general, in considering these questions, it may be stated that the consideration of an increase in plant capacity and production follows as a matter of course after a determination has been made of the year beyond which no profits are to be realized (giving the carrying. charges accumulative effect, or in other words capitalizing the carrying charges, as shown hereinafter). For example, if it is determined that any coal that is unmined after 45 years will have no value or less than no value, the question immediately arises as to whether or not a plant should be constructed that would result in a yearly production great enough to extract the entire tonnage in a time less than 45 years, and if so the number 'of years less than 45 years that would, from a financial stand-point, be the most desirable, all under the assumption that the market for the product or the transportation facilities are such that the yearly production can be increased to the desired amount.

Jan 1, 1933

By G. R. Love, M. L. Picklesimer

Aboue 950°C the Nb-Zr system consists of a completely miscible bcc solid solution, commonly called the phase. Between 950 and 600°C, and between 20 and 85 pct Nb, the phase deconlposes, after sunciently long times, into two bcc solid solutions. The pct Zr alloys are conveniently descibecl with T-T-T (time-temperature-transformation) curves having a nose at about 2 hr at 700°C. The reaction rate varies only slowly with zirconium content and negligibly with oxygen contanzination; it is speeded up by a factor of 10 to 15 by 90 pct cold ulork and slowed dou by n factor oj 10 to 30 by a two-hundrecljold increase in grain size. Nb-r alloys with compositions between 40 and 85 pct Nb have been the basis for the majority of commercially important superconducting materials. In part because of their commercial promise, more is known about these alloys than about most other high-field superconducting materials. At the same time, there is considerable disputed or incomplete metallurgical information. For example, although Rogers and tkins&apos; indicate a monotectoid reaction at approximately 600°C and a two-phase 01 + 0, field extending between 20 and 85 pct Nb and to a maximum of 95OGC, erhout&apos; has reported that this entire region would be a single homogeneous B were it not for oxygen contamination. Again, although it has been shown that relatively short-time heat treatments in the vicinity of 700CZ significantly improve the ability of short wire samples to carry high currents in high magnetic fields at 4.2K, these observations have never been fully correlated with the structural change or changes occurring during the anneal. We intend to investigate in detail the effect of metallurgical variables, including heat treatment, on the superconducting properties of hard superconductors. To verify that our experimental techniques are valid and to establish a relative standard against which other materials may be measured, we feel it advisable to know the behavior of the Nb-Zr alloys under a variety of processing conditions. As an initial step toward this goal, we have determined in detail the kinetics of the transformations in Nb-Zr alloys. EXPERIMENT A number of problems had to be solved before beginning any fruitful work on the reaction kinetics in this system. While solving some of these problems, either by chance or by design, small amounts of information were obtained about alloys containing 40, 50, 60, 65, 67, 70, and 75 pct Nb, bal. Zr. In addition, a large range of grain sizes and a range of temperatures considerably greater than the range indicated by Rogers and Atkins phase diagram were examined. We will, however, report in detail only the results obtained for the Nb + 33 pct Zr and Nb + 25 pct Zr alloys at three grain sizes, two levels of oxygen contamination, and the temperature range 550 to 950°C. These data are most complete, but the other data are sufficiently complete to indicate the kind and magnitude of the variation of the transformation kinetics outside this range. The first and most difficult problem encountered in this inquiry was one of sample homogeneity. When Nb-Zr alloys are arc- or electron-beam-melted on a cooled copper hearth, solidification is sufficiently slow that there is appreciable coring in the cast structure and a large variation of grain size across the button thickness. Both these factors significantly affect the apparent reaction rate in the system. A two-step solution to the problem was attempted; an arc-melting and drop-casting technique has been developed by conald that greatly reduces the as-cast grain size and virtually eliminates coring segregation. Ingots made in this way exhibited no detectable (3 pct maximum) zirconium segregation. Before it was evident just how good this technique was, we attempted to supplement it with rather long-time, high-temperature annealing of the cast ingots. This annealing was carried out in evacuated and sealed (seal-off pressures < 1.0 x 106 torr) quartz capsules lined with tantalum foil at 1400 to 1450 C for 8 to 72 hr. There were two principal effects of this treatment: the grain size increased to a fairly uniform 150 p, and the surface and all grain boundaries near the surface acquired a film of a second phase, tentatively identified as an oxide (possibly additionally contaminated with silicon). There was no evidence that this 1400 C treatment had affected the zirconium segregation. High-temperature annealing was subsequently used only for grain-size control, but anneals of longer than 4 hr at temperatures greater than 1000°C were performed in dynamic vacuums (pressure no greater than 1.0 x lo torr). Any contamination resulting from these treatments was well below the limits of detection of our techniques. All samples, as cast, were cold-swaged to at least 85 pct reduction in area. The samples called cold-worked were tested as swaged. The minimum re-crystallization anneal for these alloys was about 12 hr at 1050 C; this produced an equiaxed grain diameter of about 4 to 8 P. Annealing for 4 hr at 1450°C produced a grain size of about 80 to 150 p; and annealing for 4 hr at 1650aC, close to the melting point of many of these alloys, produced a grain size of 0.5 to 1.0 mm. At all temperatures, the larger grain size was

Jan 1, 1967

By R. J. Wasilewski

Axial expansion has been determined by X-ray diffraction up to 600° to 760°C in a titanium and four high-oxygen alloys. Expansion data cannot be fitted to the usual quadratic expression and anomalies observed are believed indicative of the changes in the bonding configuration of the valence electrons. Furthermore, there is significant disagreement between data obtained on poly crystalline and single crystal powder specimens. The major disagreement occurs within the temperature range (-470°C) where both mechanical and electrical properties also show markedly anomalous behavior. X. HIS work forms part of an investigation of physical properties of pure titanium and its osolid solutiono alloys with oxygen and nitrogen. In view of the anomalies observed in both the electrical resistivity&apos; and the susceptibility behavior it was decided accurately to determine the thermal expansion behavior of the pure and alloyed a titanium. PREVIOUS WORK The axial expansion coefficients reported for pure titanium are listed below. As can be seen, there is a marked discrepancy between the axial expansion and the experimentally determined coefficients on poly crystal line material. Thus, if we take the most recently reported axial expansivities3,4 we obtain perature interval of 25o to 700°C. The experimental value reported for polycrystalline metal is, however, of the order of 9.7 x 10o6 per OC. EXPERIMENTAL I) Pure Titanium. High purity titanium powder of -325 mesh was used throughout most of this work. The only significant impurities present were the interstitials, oxygen and nitrogen, which analyzed respectively 650 and 80 ppm. The purity of the ma-

Jan 1, 1962

By W. A. Cole, E. L. Derby, J. F. Wolff

Exploration of Lake Superior iron ores is done principally by drilling. The soft iron ores are churn drilled and the harder ores are diamond drilled. The churn drill used is the Mesabi type and its operation should be described as "water jetting." The drill rods are washed down by the combination action of the water jetting from the bit at the lower end of the rods and the churning motion given the line of rods. The water, which is forced down through the rods, comes up between the wash rods and the casing, bringing the choppings to the surface. It is caught in three or more barrels, each of which has a stoppered hole 8-10 in. from the bottom. These barrels are successively filled, allowed to settle, and drained to the hole, until the desired depth is drilled. The sediment from each barrel is transferred to a settling tub in which it is allowed to settle; the water is then drawn off and the wet sample is collected and dried. The number of barrels used depends on the character of the ore. For example, when drilling sandy ores, all the wash water is caught and settled for the proper length of time without refilling any of the barrels. Thus, the sediment held below the stoppered hole in any one barrel is not disturbed. The casing is kept as near the bottom of the hole as practicable to prevent the caving of the hole from jeopardizing the sample. While the casing is being driven down and the hole is being washed clean after casing, the return water is not run into the sample barrels. In exploratory work in the harder formations, where the diamond drill is used, the sample comprises both core and cuttings. The care given in handling and preserving the core depends on the importance that may be attached to certain characteristic strata in different formations. The following instructions for the care of core samples are issued by the Ogle-bay Norton Co. for diamond drill work done for them on the Gogebic Range of Michigan:

Jan 1, 1925

By W. L. Mamme, G. Y. Chin

The problem of selection of the active slip systems for a crystal undergoing an arbitrary strain was analyzed by Taylor and by Bishop and Hill in terms of a minimum (internal) and a maximum (external) work criterion, respectively. These two criteria have now been generalized to include crystallographic slip on several sets of slip systems, twinning mixed with slip, and slip by (noncrystallographic) pencil glide. The generalized treatment also takes into account the possibility of a Bauschinger effect and of unequal hardening among the shear systems, which were considered in the Bishop and Hill work. Optimization techniques of linear and nonlinear programming are shown to be applicable for the numerical calculation of the minimum or maximum work. In the case of crystallographic shear, the constraint functions are linear and hence the optimal work is obtained as the saddle value of the lagrangian function Wi(y) e minimum and W,(u) + (a) for the maximum, where Wi is the (internal) work, We is the (external) work, Y is the crystallographic shear strain, u is the applied stress, and and are constraints. It is shown that the Lagrangians are functionally the same and the saddle value of one problem is identical to the saddle value of the other, proving that the two analyses are completely equivalent. In the case of pencil glide, although the constraint functions are nonlinear and neither convex nor concave, the equivalence of the optimal values to the saddle value of the Lagrangian (which is again identical for both problems) is still valid. WHEN a crystal deforms plastically by crystallographic shear, five independent shears are generally required to accommodate five independent strain components specifying the deformation. Assuming slip as the only shear mechanism, Taylor1 in 1938 analyzed the deformation in terms of a minimum work criterion. He hypothesized that of all combinations of five slip systems which are capable of accommodating the deformation, the active combination is that one for which the internal work C is a minimum, where 1 TI is the critical resolved shear stress for slip on the 1-th slip system and is the corresponding simple shear. By further assuming equal 72 for all equivalent slip systems and no Bauschinger effect, Taylor re- duced the minimum work problem to one of minimum and applied the analysis to the case of axisym- Metric flow by {111}(110) slip in fcc crystals. However, he did not consider the question of whether the resolved shear stress has in fact attained the critical value for slip on the newly found active systems without exceeding it on the inactive systems. In 1951 Bishop and ill&apos; put forth the maximum work analysis in which slip is again assumed as the only deformation mechanism. In this analysis, the work o1 done in a given strain ij by a stress ujj not violating the yield condition is maximized. In addition, the analysis takes into account the possibility that the critical resolved shear stress for slip may not be equal among the slip systems and that the slip behavior may exhibit the Bauschinger effect. As with Taylor, a single set of slip systems—{111)(110) — was analyzed numerically. It thus appears that the Bishop and Hill treatment is on a more sound physical basis than the Taylor treatment. However, Bishop and Hill showed that where there is equal hardening among all slip systems and when there is no Bauschinger effect, Eq. [11 ] of Ref. 2, as assumed by Taylor, the results of their maximum work analysis are the same as those of Taylor&apos;s minimum work analysis. Hence at least under those conditions there is an implication that the Taylor analysis does lead to a critical resolved shear stress for slip on the predicted active systems without violating the yield condition on the inactive systems. Recently, the Taylor analysis was applied for numerical solutions of the axisymmetric flow problem, for slip on {110}(111), {112}(111). {123)(111) systems as well as a mixture of all three sets of svstems."1 Computational techniques based on the optimization theories of linear and nonlinear programming4 were employed in these solutions. The same techniques were employed in the solutions of an axisymmetric flow problem of deformation by slip on (111) (110) systems and twinning on (111)(112) systems5 which had been considered theoretically from a modified Taylor approach. The utilization of these techniques has led to the realization that the solutions of Taylor&apos;s minimum work problem imply the solutions of Bishop and Hill&apos;s maximum work problem. The two problems turn out to be dual problems in the well known sense of mathematical programming. It is thus the purpose of this paper to first generalize the minimum and maximum work analyses to include crystallographic slip on several sets of slip systems, twinning mixed with slip, and slip by (non-crystallographic) pencil glide, as well as the possibility of a Bauschinger effect and of unequal hardening

Jan 1, 1970

By E. B. Hughes, F. G. Norris

Oxidation is characteristic of all processes for making steel from pig iron. This thought has been aptly expressed by H. W. Graham13 in the recent Howe Memorial Lecture, "The process of steel-making consists of using iron oxide to reduce the carbon content of the pig iron to the desired level." Direct oxidation refers to the reaction that results from introducing oxygen either alone or mixed with other gases directly into the steel bath. In working a heat, oxygen in some form is added to the steel to remove the undesirable constituents as oxides. There are two general methods of supplying this oxygen to the open hearth bath. The method in which the oxygen is added as a compound such as Con or iron ore is designated an indirect method because the steel bath must first decompose the compound to attain oxygen in a usable form. The other method in which oxygen is added to the bath in the elemental or gaseous form, more or less diluted by other gases such as nitrogen, is a direct method because no decomposition is necessary before the oxygen reacts with iron to form FeO which is dissolved in the bath in a usable form. Bubble formation (at least of a macroscopic size) presents no problem in case of direct oxidation because the reacting agent (oxygen) is in the form of bubbles when entering the metal. Regardless of whether oxygen is intro- duced into the bath directly or indirectly, several reactions proceed concurrently. In the presence of the bath of molten iron, FeO is formed either by oxidation of iron by oxygen or reduction of oxides by iron. This FeO dissolved in the molten iron is the source of oxygen for the oxidation of manganese, carbon, silicon, and phosphorus if these are present. The oxidation of carbon from steel is the controlling steelmaking reaction. The introduction of oxygen into the bath, its reaction in the elimination of impurities, and its control by the use of de-oxidizing additions have been subjects of importance since steel was first made by the bessemer process. Direct oxidation is, in a sense, an application of the bessemer principle to the open hearth process. Graham13 states: "The use of oxygen or air jets introduced into the metal bath is essentially an effort to approach in the open hearth the turbulence, rapid interface reaction, and high production rate per hour that exists in the bessemer process." The general subject, "Oxygen in Steel-making," was given new life by the studies of Herty and associates starting about1925. The current interest in elemental oxygen is intimately related to the large scale production of oxygen developed during the war period. Some of the first applications were made during the early summer of 1946 at the Steel Co. of Canada using oxygen with the fuel. Such a use is of considerable interest and importance in contributing to faster heats but is not the subject of the present discussion which deals entirely with the introduction of elemental oxygen directly into the open hearth bath.

Jan 1, 1949

By E. B. Hughes, F. G. Norris

Oxidation is characteristic of all processes for making steel from pig iron. This thought has been aptly expressed by H. W. Graham13 in the recent Howe Memorial Lecture, "The process of steel-making consists of using iron oxide to reduce the carbon content of the pig iron to the desired level." Direct oxidation refers to the reaction that results from introducing oxygen either alone or mixed with other gases directly into the steel bath. In working a heat, oxygen in some form is added to the steel to remove the undesirable constituents as oxides. There are two general methods of supplying this oxygen to the open hearth bath. The method in which the oxygen is added as a compound such as Con or iron ore is designated an indirect method because the steel bath must first decompose the compound to attain oxygen in a usable form. The other method in which oxygen is added to the bath in the elemental or gaseous form, more or less diluted by other gases such as nitrogen, is a direct method because no decomposition is necessary before the oxygen reacts with iron to form FeO which is dissolved in the bath in a usable form. Bubble formation (at least of a macroscopic size) presents no problem in case of direct oxidation because the reacting agent (oxygen) is in the form of bubbles when entering the metal. Regardless of whether oxygen is intro- duced into the bath directly or indirectly, several reactions proceed concurrently. In the presence of the bath of molten iron, FeO is formed either by oxidation of iron by oxygen or reduction of oxides by iron. This FeO dissolved in the molten iron is the source of oxygen for the oxidation of manganese, carbon, silicon, and phosphorus if these are present. The oxidation of carbon from steel is the controlling steelmaking reaction. The introduction of oxygen into the bath, its reaction in the elimination of impurities, and its control by the use of de-oxidizing additions have been subjects of importance since steel was first made by the bessemer process. Direct oxidation is, in a sense, an application of the bessemer principle to the open hearth process. Graham13 states: "The use of oxygen or air jets introduced into the metal bath is essentially an effort to approach in the open hearth the turbulence, rapid interface reaction, and high production rate per hour that exists in the bessemer process." The general subject, "Oxygen in Steel-making," was given new life by the studies of Herty and associates starting about1925. The current interest in elemental oxygen is intimately related to the large scale production of oxygen developed during the war period. Some of the first applications were made during the early summer of 1946 at the Steel Co. of Canada using oxygen with the fuel. Such a use is of considerable interest and importance in contributing to faster heats but is not the subject of the present discussion which deals entirely with the introduction of elemental oxygen directly into the open hearth bath.

Jan 1, 1949

By J. P. Timmons, J. H. Moran, G. K. Miller, M. A. Coufleau

A prototype equipment has been designed and built for the digital recording of well logs on magnetic tape at the same time that the regular film recording is made. The format of the digital tape produced is such that it can be used directly at the input of the ZBM 704, 7090 or other models of ZBM computers which accept digital magnetic tape. This apparatus has been used for the experimental field recording of dipmeter tape logs which were subsequently computed by means of an ZBM 704 or 7090. In this paper the equipment and the digital tape are described briefly, and their application to the computer-interpretation of dipmeter data is discussed. A principal element in the interpretation of the dipmeter log is the correlation of the three microresirtivity dipmeter curves to determine the depth displacements between them. Several correlation methods for computer use are considered, with particular attention to their sensitivity to error and their consumption of computer time. The tape data were used to compute information content of the dipmeter microresistivity curves in terms of their frequency spectra. The results show that the sampling rate used in recording the digital information is quite adequate and illustrate a use of the digital tape in evaluating the characteristics of new tools. Some examples of field results are shown. It can be foreseen that, when digital tape recording becomes available for general field use, a whole new realm of possibilities will be opened up for the processing of other well logs through computations, which hitherto were not feasible because they were too laborious and time-con.sunzing. INTRODUCTION The last few years have seen a revolution in the design and production of data-processing equipment. Stored-pro-gram digital computers have progressed from a research curiosity to the basis of a major industry. There are now hundreds of such machines in daily use in the United States. With the acceptance of a technique that was, in fact, already clearly described by John von Neumann in 1945, the last decade has seen great strides in the development&apos;of components, reliability, programming systems and, most spectacularly, in the sheer number of machines built and in use. In 1957 there were enough digital computers available to the oil industry to justify the suggestion that it would be worthwhile to investigate the possibility of using these machines in processing well log data.&apos; The first result of this investigation was the appearance of what may be referred to as the input-output bottleneck. Well logs are customarily recorded on film. To get these data into a machine required then (and still does): a time-consuming semi-automatic reading of the film; conversion of the log data to digital form; and recording these digital data in some medium acceptable for computer input, such as cards, magnetic tape, or punched paper tape. However, the recording, reading, and re-recording could only result in deterioration of the data. Therefore, it was concluded that the fist step should be the development of a new, more direct recording technique supplemental to the film recording, which would provide easy access to the digital computer. There are many solutions to the problem of recording log data in an easily recoverable form. After careful consideration it was decided to adopt the boldest solution which, it was felt, was also the most elegant. It was decided to record well logs directly, in the field, on magnetic tape in such a way that this tape could be used without further modification as an input to the IBM 704 or 7090 computer. To realize practical field recording of magnetic tape logs, it became necessary to develop in a rather small package, an analog-to-digital converter, a tape recorder, and the necessary multiplexing and control circuits to allow the simultaneous recording of a multiplicity of logging signals. The magnetic tape recording was to be made simultaneously with the conventional logging operation in such a way as not to interfere with it. Along with the development of hardware, it was necessary to begin development of interpretation techniques and machine programs that would exploit the power of the digital computer. Here, again, there is a long list of possible applications. After much consideration it was decided to concentrate on the interpretation of the dipmeter log as a first application. It is the object of this paper to describe in some detail the developments sketched in the last three paragraphs.

By Philip Wilson

Tun mines of the Calumet & Arizona Mining Co. are situated in the Warren Mining District, Cochise County, Arizona, between Bisbee and Warren and adjoin those of the Copper Queen Consolidated Mining Co. and the Shattuck Arizona Copper Co. Paleozoic limestones of considerable thickness have been intruded by granite porphyry. A great stock of the intrusive outcrops boldly near the city of Bisbee and is known as Sacramento Hill. From this central core the porphyry has tongued out into the limestone for many thousands of feet as dikes and sills of irregular shape and variable dimensions. Churn drilling has recently developed a large tonnage of secondarily enriched copper ore in the main porphyry mass of Sacramento Hill. While some ore has been found in porphyry in other parts of the district it is relatively unimportant compared with that which occurs in the Paleozoic limestone as irregular lenses replacing favorable beds near porphyry contacts or associated with well-marked fracture zones often many hundreds of feet away from the intrusive. In a zone extending from Sacramento Hill for a distance of from 1,500 to 3,000 ft. the limestone has been extensively metamorphosed and in this contact metamorphic zone the ore occurs through a known vertical thickness of upward of 900 ft. and individual orebodies often show extension in a vertical direction of over 200 ft. At a greater distance from the intrusive stock the ore occurs as lenses of greater horizontal than vertical dimensions with an average thickness of approximately 30 ft. An exception to this rule is found in the occasional steeply dipping mineralized fractures, almost true tabular veins, which are found long distances away from the zone of contact metamorphism.

Jan 7, 1916

By Claus G. Goetzel

PRESSING of powdered metal parts is best done in the direction of the shortest extension of the piece, to avoid too great a loss of pressing force through internal [ ] friction. As long as curved surfaces, recesses, or offsets occur only parallel to this shortest axis of pressure, no special difficulties arise: the cross sections, perpendicular to the pressure, do not vary, nor does the shape of the parts change during compression except for a gradually reduced thickness (Fig. IA). The problem becomes more difficult, however, when the curved surfaces or recesses are perpendicular to the shortest axis of the part (Fig. IB). Two processes for molding uniformly dense parts with complicated shapes from powdered metals are described in detail in this paper. Both can be employed successfully by those trained in the art. The first refers to curved parts; the second is especially adapted to parts having one or more recesses or steps. Both methods, as set forth here, are applied under the condition that presents the more difficult problem. For clarity, before description of the two practical methods, the variable factors in molding powdered metal parts will be reviewed, then an idealized procedure will be considered briefly. VARIABLE FACTORS IN MOLDING POWDERED METAL PARTS Compression Ratio Compression ratio is defined as the proportion of the final relative density of the compact to the apparent density of the powder. For iron powder of an apparent density of 3.0, for example, a compression ratio of 2 1/2 : I would be required to produce a compressed compact of 7.5 density; whereas for another iron powder having an apparent density of only I.5, a compression ratio of 5:I would be required to produce the same density. The lower the powder&apos;s apparent density, the greater must be the compression ratio for pressing compacts of high density.

Jan 1, 1945

By D. Coutsouradis, L. Habraken, P. Nicolaides

The TTT curves of 0.1 pct C, 13 pct Cr steels containing up to 12 pct Co have been determined in order to establish whether the effect of cobalt is similar to that observed m plain carbon steels. It is shown that cobalt increases the incubation time and decreases the transformation rate, though not in an uniform way. The bainitic transfornation is displaced to lower temperature and overlaps partially the martensitic zone. ThE effect of cobalt on the transformation of a plain carbon austenite has been studied by many investi-gators.&apos;-3 It was shown that cobalt displaces the TTT curves to shorter times and diminishes the harden-ability. The interpretations given for this effect of cobalt are conflicting. According to E. Houdremont,4 cobalt increases the transformation rate of austenite because it increases the diffusion of carbon as shown in the experiments of E. Houdremont and H.Schrader,&apos; R.Smoluchowski,5 and M. Blanter.6 On the other hand, M. Hawites and R. Mehl3 deny on the basis of their own experiments any effect of cobalt on the diffusion of carbon and they assume that an explanation should be found in an eventual effect of cobalt on the mechanism of nucleation and growth of pearlite. W. C. Hagel, G. M. Pound, and R. F. Mehl7 have shown by calorimetric measurements that cobalt increases the free energy of the austenite-pearlite transformation in an eutectoid steel and this result explains qualitatively the observed effect of cobalt on the rate of nucleation and growth of pearlite. The purpose of this research was to see by determination of TTT curves, if this same effect exists in 13 pct Cr steels. EXPERIMENTAL PROCEDURES The preparation of the alloys was carried out in an

Jan 1, 1960