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By W. S. Owen, A. R. Rosenfield

The measured changes in the yield stress of a poly crystalline Ta-O alloy after strain aging at 100°C have been separated into two components; the change inflow stress and the change in dislocation locking parameter. These two components vary independently indicating that at least two separate recovery processes take place during strain-aging. Variations in the locking parameter can be accounted for by segregation of oxygen atoms to dislocations, but variations inflow stress cannot be explained by current theories. STRAIN-AGING in Fe-C and Fe-N alloys has been studied extensively.' The kinetics of the removal of the interstitial solute from solution appear to agree with the predictions of the cottrell-bilby2 model or a variation of it proposed by harper.3 Solute segregates to the dislocations under the influence of the elastic strain field of the dislocation and the rate of depletion of the solute can be measured by following the change in electrical resistivity4 or internal friction.5 On reloading a prestrained specimen, plastic flow starts at Fig. 1, but after aging the reloaded specimen yields discontinuously at a higher stress The aging index reflects the extent to which the yield has returned. Until recently it was usual to assume that ? is a result solely of the pinning of dislocations by the segregated solute atoms, that is, that op and oj coincide and the strain hardening curves AB and CD are continuous. Thomas

Jan 1, 1963

By J. E. Smith, P. B. Crawford, B. L. Laudrum

A method is presented by which the displacement efficiency of a steam-injection process may be determined. The method consists of a determination of the position of the steam front at a particular time and the application of the Buckley-Leverett theory to the hot and cold regions of the reservoir with the appropriate hot or cold fluid properties. A uniform, linear flow system is assumed for this study. The method is applied to a number of reservoir conditions. The primary properties which affect the results of a steam-injection process are the oil viscosities at steam and reservoir temperatures, injection rate, pay thickness and oil saturation. The efficiency of steam injection is compared with that of water injection for a 10-acre, linearly flooded reservoir. In reservoirs where the oil viscosity is about 35 times the water viscosity, the steam process yields recoveries about 20 per cent higher than the water flood. Where the oil viscosity is near 500 cp, the steam process may recover from three to four times as much oil as a water flood. INTRODUCTION In a previous paper,' a method was suggested for evaluating a steam-injection process. Emphasis was placed upon the determination of the steam-front position in the reservoir at various times. In the present paper, the displacement process is studied in more detail. The approach is essentially that employed by Jordan, Rayne and Marshall3 in their study of hot-water injection. The steam-injection process is quite complex, and an exact description of the process has not been found; however, a qualitative description can be made. When a quantity of steam is injected into a relatively cold reservoir, the leading edge of the steam front continaally flows into cool sand, and some steam condenses. As more and more steam condenses, a bank of condensed water will form which is augmented by displaced connate water. The reservoir may be divided in three regions—(1) a region containing displaced fluids at reservoir temperatures, (2) a region contain- ing water at reservoir temperature and (3) a region occupied by steam. The reasons for the lack of a region of hot water or oil of any appreciable size have been discussed.' A method has been presented by which the location of the steam front can be determined even when heat losses to the regions surrounding the reservoir are sizable compared with the amount of heat injected. It remains to show the effectiveness of steam injection in increasing the ultimate oil recovery. To illustrate the technique for determining the increase in displacement efficiency and, hence, the increase in ultimate production, two sets of hypothetical reservoir conditions will be studied in detail.

By C. M. Nickerson

In times of overproduction such as the operators have been struggling against for the past several years it is the practice of the oil industry to shut in certain wells in order to reduce the flood of oil. The purpose of this paper is to present certain variations in production of oil wells when the offset wells are shut in. The scope of the study has been confined to California fields, and more especially to those of the San Joaquin Valley. The accepted definition of a shut-in well is a well where production has been suspended by closing in the casinghead arid tubing or by cessation of pumping. The immediate effect of such a procedure, of course, is to reduce the oil production from the lease, which is the result desired. However, it appears that certain types of wells vary widely in production of oil, gas and gasoline after adjacent wells have been shut in, which variation has a very material effect on the ultimate recovery of oil from the property. The increase or decrease in the oil production itself may not be of sufficient volume to occasion comment, but wide fluctuations in the gas and gasoline recovery under the changed conditions arc of the utmost importance in the future recovery of oil. The scope of this paper includes: (I) the effect on producing oil wells of shutting in offset wells, the wells being studied in three groups arranged according to their relative stages of depletion; (2) probable source of excess gas and the effect on the ultimate recovery of oil; (3) suggested procedure when wells are shut in; (4) methods that could be employed to prevent undue migration of gas from the shut-in area; and (5) the need for future studies of the situation. Three Classes of Producing Oil Wells For the purposes of this paper producing wells in California have been arranged in three groups according to the age of the well, or to the relative stage of depletion of the producing zones. The first group consists of those wells with a high fluid level, or in other words those wells whose fluid levels are a considerable distance above the top of the perforations. This type of well is in the flush period of its life and ordinarily produces

Jan 1, 1929

By John M. Logan, John Handin

Quasi-dynamic triaxial compression tests have been done for the first time at confining pressures to 7 kb. The intermediate strain-rate apparatus employs a gas loading cylinder which allows axial strain rates up to 102/sec on a sample 2 cm in diameter and 4 cm long. Samples can be deformed at confining pressures to 7 kb. Strain gages bonded to the loading piston and to the jacketed specimen allow internal measurements of load and sample strains respectively. Westerly granite has been deformed at confining pressures to 7 kb, room temperature, and axial strain rates of 10-2 to 1/sec. An increase of ultimate strength with confining pressure was found as expected. The ultimate strength was also found to vary directly with increasing strain rate; the rate of rise increases with confining pressure. Brittle deformation has dominated the sample behavior. Solenhofen limestone has been deformed at confining pressures to 3 kb, room temperature, and axial strain rates of 10- to 10/sec. The brittle-ductile transition was found to take place at about 1.5 kb confining pressure at a strain rate of 10/sec.

Jan 1, 1971

By C. G. Dunn

According to a recently suggested effect of silicon on the re recrystallization textures of high-purity Fe-Si alloys with (111)[112] type rolling textures, the recrystallization texture for a rolled (110)[001] oriented iron crystal probably should be entirely different from that of a (110)[001] oriented 3 pct Si-Fe crystal. Comparative studies of iron and 3 pct Si-Fe crystals, however, show that both have (110)[Ool] recrystallization textures when the rolling textures are the (111)[112] type after reductions in thickness of about 70 pct. Qualitatively the results from the iron crystal are like those of polycrystalline high-purity 3 pct Si-Fe and not like polycrys-talline high-purity iron. The large effect previously noted probably involves unknown impurities or processing variables rather than silicon itself. Some problems on experimental and analytical procedure for a spherical X-ray specimen, which was machined from a laminated composite of sheet specimens, are treated in the Appendix. A possible strong effect of silicon on the textures produced in cold-rolled high-purity Fe-Si (HPFe-Si) alloys during primary recrystallization and normal grain growth was suggested in a recent paper.' All the textures were far from the random-orientation type, but that of iron, or of Fe-Si alloys of low silicon composition, was entirely different from the texture of 3 pct Si-Fe. The same effect was noted for the textures obtained prior to normal grain growth, i.e., for primary recrystallization.2 It is the main purpose of the present paper to provide some clarification of this silicon effect. All the HPFe-Si alloys from zero to 3 pct Si, which were rolled by two or more stages separated by anneals, developed (111)[112] type rolling textures.2 Thus, there was no effect of silicon on the rolling textures. Earlier, Gensamer and Mehl3 also found no effect of silicon on the rolling textures of Fe-Si alloys; they obtained the Kurdjum.ow and Sachs (K-S) rolling texture for iron,4 which is characterized as the three ideal components: (100)[011], (112)[li0], and (111)[112]. There is a difference between the HPFe-Si multiple-stage rolling texture and the K-S single-stage rolling texture, but this is a variable processing effect. Of interest here is the fact that the recrystallization textures from (111) [llZ] type rolling textures were different depending on the amount of silicon in the alloy. There was a relatively strong (110) [001] component in the recrystallization texture of HP 3 pct Si-Fe5,8,2 but no such component in HP 0.6 pct Si-Fe, for example; the recrystallization texture for the latter was two (111) [110] type components and a (111) fiber component 1,2 Several publications have shown that a strong (110) [001] recrystallization texture is derivable from a (111) [112] type rolling texture for 3 pct Si-Fe crystals reduced in thickness by about 70 pct.7-10 Furthermore it appears that the strongest of these (110) [001] recrystallization textures occurred when the orientation of the crystal prior to rolling was (110) [001].7 Barrett and evensoon11 found that the rolling texture of a (110)[001] oriented iron crystal was (111) [llj]. Accordingly, it seemed desirable to determine whether a (110) [001] oriented iron crystal, upon rolling and annealing, would behave like the 3 pct Si-Fe crystal (or the polycrystalline HP 3 pct Si-Fe) and thus produce a (110) [001] recrystallization texture contrary to the suggested silicon effect, or would behave like the polycry stalline HP iron or HP 0.6 pct Si-Fe and thus produce (lll) [110] type components in agreement with a silicon effect. Briefly, the idea here involves the use of more precisely defined textures to obtain if possible better control of important variables that affect the recrystallization process. PROCEDURE A (110) oriented crystal of Ferrovac "E" iron (99.9 pct pure) was prepared in sheet form 0.080 in. thick with the [001] direction parallel to the long dimension of the specimen.'' This crystal was etched to 0.073 in. thickness (to remove some small included grains) and then was cold rolled in a 6-in.-diam mill to a final thickness of 0.022 in. The rolling was unidirectional except for an inadvertent reversal at 0.061 in. thickness. At this thickness, and also at 0.040 in., the rolling was interrupted for transmission Laue photographs. Molybdenum Ka-radiation filtered with zirconium was used in a transmission method1' to obtain the cold-rolled (110) pole figure. The sample was a 0.002-in.-thick section taken from the central region of the 0.022-in.-thick cold-rolled crystal. For the primary recrystallization study, cold-rolled samples were etched from 0.022 to 0.021 in. thick and annealed in hydrogen at 850°C. Primary recrystallization to a fine-grained structure, Fig. 1, was obtained in a 5-min anneal. Eleven sheets after

Jan 1, 1963

By D. J. McAdam

As shown in three recent papers by the author,6,7,8 in two papers by McAdam and Mebs,9,10 and in a paper by McAdam, Mebs, and Geil,11 the technical cohesive strength of a metal, in any particular state as regards mechanical treatment and heat-treatment, cannot be represented by a single stress value, but must be represented by a diagram with the principal stresses? as coordinates. Each point on the boundary of such a diagram represents a technical cohesion limit. The technical cohesive strength thus comprises an infinite number of technical cohesion limits, each representing fracture under a specific stress combination. Moreover, neither the yield strengths nor the ultimate strength can be represented completely by a single stress value, but must be represented by a diagram with the principal stresses as coordinates. All combinations of the principal stresses may be classified in three groups as illustrated by Fig. I. Fig. Ia shows three typical stress combinations with no two principal stresses equal. The magnitude of each principal stress is indicated qualitatively by the length of the arrow. Arrows pointing away from the cube indicate tensile stresses; arrows pointing toward the cube indicate compressive stresses. Typical stress combinations with two principal stresses equal are illustrated in Figs. Ib and Ic. Such stress combinations would be produced by subjecting a cylinder to combinations of uniform axial and radial stresses. The uniform radial stress may be resolved into two equal principal stresses, with the mutually perpendicular directions rotatable around the axis of the cylinder. Fig. Ib shows stress combinations with S2 equal to Sa. The greatest principal stress is in the axial direction, and the stress combination tends to cause either absolute or relative increase in length.* Fig. Ia shows stress combinations with Ss equal to Sl. The greatest principal stress is in the radial direction, and the combination tends to cause either absolute or relative decrease in length. The complete representation of either technical cohesive strength, yield strength, or ultimate strength generally requires a three-dimensional diagram. When two of the principal stresses are kept equal, however, the strength of a metal may be represented by a two-dimensional diagram with the coordinates representing the axial and radial stresses.6-11 In this paper, attention will be confined almost entirely to stress combinations with two of the prin-

Jan 1, 1944

By Mark R. Lamb

THE treatment of slime is of special interest to those engaged in cyaniding gold- and silver-ores. The usual practice is to make as small a percentage of slime as possible. In many instances the slime is given no treatment, but is impounded in dams in the hope that the future will develop some method of economically treating this product. The filter-press was the first step upward from ordinary decantation, but, on account of heavy labor-charge and high cost, its use has been limited to high-grade material. The slime at the Combination mill at Goldfield averages perhaps $20 per ton, and although the values are quickly dissolved the filter-press installation was not entirely satisfactory, resulting in the erection of the canvas-cell filter, developed by Chas. Butters and his staff. This filter is a great improvement over the filter-press, and the following description of it will be of interest to those engaged in treating slime produced in crushing ores, especially in view of the fact that, by the use of this filter, slime can be treated at a lesser cost and with a higher percentage of gold- or silver-extraction than in the ordinary treatment of sand; and, moreover, the initial outlay for an all-sliming plant is less than that for the ordinary sand- and slime-plant. The economy of construction of the Butters filter-plant is clearly shown in Figs. 1 and 2, which illustrate the 20-frame filter of 40 tons capacity, now being installed by the Nevada Goldfield Reduction Co. In this construction the slime-pump is so connected that it can pump to or from either tank or the filter by changing the valve-settings-a combination which is necessary in this particular installation, since sufficient fall is not available for filling and discharging the filter by gravity. Ordinarily, a slime-plant comprises: a filter-box with frames

Jan 1, 1907

By M. C. Udy, F. W. Boulger

AN incomplete phase diagram for the U-Ti systern was determined earlier 1 and more recently, a tentative diagram was presented for the uranium-rich end of the system.' In the present re-examination of the whole system of U-Ti alloys, high purity materials were used. Melting stock for the alloys was high purity uranium, containing about 0.09 pct C as the only appreciable impurity, and high purity iodide-process titanium purchased from New Jersey Zinc Co. Both metals were cold rolled to about 1/6 in. thickness, sheared to about I/' in. squares, and cleaned by pickling. The alloys were arc melted under a helium atmosphere in a water-cooled copper crucible. A thoriated-tungsten electrode was used. The furnace chamber was evacuated, then flushed with helium, prior to each melting. It was finally filled with stagnant helium at one atmosphere pressure. Each alloy was remelted three times after the original melting, to insure homogeneity. The alloy button was turned bottom side up before each re-melting operation. Some 22 alloys were examined. Their compositions were spaced at appropriate intervals between 100 pct Ti and 100 pct U. Analyses were made on chips taken after fabrication. The major contaminant was carbon, which varied from 0.03 to 0.08 pct. It appeared in the microstructure as titanium carbide. Alloy compositions were calculated to a carbon-free basis for consideration on the diagram. Tungsten and copper, possible contaminants from the melting operation, were generally less than 100 parts per million each. Fabrication All alloys were forged and rolled to bars approximately V8 in. square. They were clad either in SAE 1020 steel or in a 5 pct Cr-3 pct Al-Ti-base alloy, depending on the fabrication temperature. A temperature of 1800°F (980°C) was used for alloys near the compound composition. This necessitated using the titanium-base alloy, since iron reacts with titanium at this temperature, producing a low melting alloy. Other alloys were fabricated at 1450°F (790°C), using steel jackets. No iron-titanium reaction occurred at this temperature. The jackets were welded in place in an argon atmosphere. Those alloys sheathed in steel were declad and then reclad between rolling and forging operations. On the other hand, those clad with the titanium alloy were cut to a roughly rectangular shape prior to clading and were then carried through both the forging and rolling operations without opening. Those alloys near the compound composition were found to be cracked when the clading was removed. The cracked materials had been plastically deformed, however, and at least some of the cracking had OCcurred during cooling. Heat Treatment The rolled bars, after being declad and shaped to remove surface contamination, were all given an homogenizing treatment of 160 hr at 2000°F. (Samples were taken for analysis following the declading and shaping operations.) All were heat treated at the same time in one furnace, but each was sealed in a purified argon atmosphere in an individual Vycor glass tube. Argon pressure was such that it was approximately atmospheric at temperature. One end of each tube contained titanium chips and this end was heated to 1200°F (650°C) for 10 min prior to the heat treatment. This purged the atmosphere of residual reactive gases. The balance of the tube was warmed during the purge to liberate adsorbed moisture and gases, which also reacted with the hot chips. The bars were furnace cooled from the homogenization treatment. Specimens of each alloy were water quenched after 2 hr heating at 1000°, 1200°, 1400°, 1600°, 1800°, and 2000°F (540°, 650°, 760°, 870°, 980°, and 1095°C). In addition, some were treated at intermediate temperatures of 1300°, 1500°, and 1700°F (705", 815", and 925°C) and at 2150°F (1175°C). Specimens, about '/s in. cubes, were cut from the bars, sealed in individual Vycor tubes, and heat treated as described. All specimens heat treated at the same temperature were processed together. Samples were quenched by breaking the Vycor tube rapidly under water. Metallographic Examination Specimens were mounted in bakelite and ground wet on 180 grit paper held on a 1750 rpm disk. They were then ground wet by hand, using 240, 400, and 600 grit papers. The rough grinding was continued long enough to get well below the surface. Specimens were mounted separately because of the variation in the rate of etching between alloys. The specimens were polished with rouge on a 4 in., 1725 rpm wheel covered with Miracloth. Alloys on the titanium side of the compound composition were etched with a solution of 2 pct hydrofluoric acid in water saturated with oxalic acid. A few crystals of ferric nitrate were added as a bright -ener. Specimens were immersed 5 sec, polished to remove the etch, then re-etched. With the higher titanium alloys, it was often necessary to start the etch on the polishing wheel, because of the formation of a passive film. In some instances, a plain 2 pct hydrofluoric etch was satisfactory. For the alloys on the uranium side of the compound, a distinction between the compound and the uranium phase developed after standing a short time in air. This could be hastened by the application of heat, such as obtained by placing the specimen on a radiator. A deep etch was necessary to develop details in the uranium-rich phase, such as the Widmanstaetten pattern sometimes obtained by quenching y uranium. A 2 pct hydrofluoric acid solution was used for this deep etching.

Jan 1, 1955

By L. C. Aycock, J. Hunter, P. M. Lyons

In view of the unfavorable discovery trend that has set in during the past few years, it seems permissible to infer that the large, more easily found crude reserves in Louisiana are now known. Without doubt, many new producing areas will be located, but in the light of development during the past few years the majority of new areas probably will be found at greater depths and from relatively poorer sands. f Although sufficient reserves exist in Louisiana to last at the present rate of production for a considerable period, additional reserves must be found in more intensive development of the presently known structures. In order to ensure the greatest ultimate recovery from such structures, the most advanced technical methods must be employed in their exploitation. Wherever possible, cycling and repressuring plants should be installed. 'here are presently in Louisiana, especially in south Louisiana, a great many fields that contain gas-condensate reservoirs. These reservoirs cannot be produced for their liquid hydrocarbon content under present conditions without wasting an enormous quantity of gas and creating underground waste. Although some of these reservoirs are being produced, such production must be considered in the nature of a salvage operation rather than as a sound economic proposition. Such reservoirs, however, can become profitable ven- tures through the use of cycling and repressuring plants. Cycling operations now operating in Louisiana have increased the ultimate recovery from gas-condensate reservoirs anywhere from 10 to 30 per cent. Cycling operations will also provide a considerable reserve of gas, without which Louisiana cannot hope to develop any program of industrialization. During the past year, Louisiana attained the rank of third among the oil-producing states of this country. With a proper program of exploitation and development, and with emphasis on conservation, Louisiana can maintain this position for a great many years. Production On Dec. 31, 1943, oil and/or gas were being. produced in 52 parishes, or 81 per cent of all the parishes in the state. Thirty-three of the parishes produced oil and gas, 14 produced oil, and 5 produced solely gas. Tensas Parish in north Louisiana and Assumption Parish in south Louisiana formerly contained no producing fields but during 1943 joined the ranks of the producing parishes. Twenty-three new fields, including one rediscovery, were found during 1943-—a rate of discovery almost comparable to that of the preceding year. Eleven of these new discoveries were either gas or gas-condensate fields. Thus, the trend of development in finding new reserves was also comparable to that of 1942. Many reasons of considerable merit have been advanced to account for the discouraging lack of crude-oil reserves found during the past year. None are, however, completely satisfactory.

Jan 1, 1944

By J. Hunter, P. M. Lyons, L. C. Aycock

In view of the unfavorable discovery trend that has set in during the past few years, it seems permissible to infer that the large, more easily found crude reserves in Louisiana are now known. Without doubt, many new producing areas will be located, but in the light of development during the past few years the majority of new areas probably will be found at greater depths and from relatively poorer sands. f Although sufficient reserves exist in Louisiana to last at the present rate of production for a considerable period, additional reserves must be found in more intensive development of the presently known structures. In order to ensure the greatest ultimate recovery from such structures, the most advanced technical methods must be employed in their exploitation. Wherever possible, cycling and repressuring plants should be installed. 'here are presently in Louisiana, especially in south Louisiana, a great many fields that contain gas-condensate reservoirs. These reservoirs cannot be produced for their liquid hydrocarbon content under present conditions without wasting an enormous quantity of gas and creating underground waste. Although some of these reservoirs are being produced, such production must be considered in the nature of a salvage operation rather than as a sound economic proposition. Such reservoirs, however, can become profitable ven- tures through the use of cycling and repressuring plants. Cycling operations now operating in Louisiana have increased the ultimate recovery from gas-condensate reservoirs anywhere from 10 to 30 per cent. Cycling operations will also provide a considerable reserve of gas, without which Louisiana cannot hope to develop any program of industrialization. During the past year, Louisiana attained the rank of third among the oil-producing states of this country. With a proper program of exploitation and development, and with emphasis on conservation, Louisiana can maintain this position for a great many years. Production On Dec. 31, 1943, oil and/or gas were being. produced in 52 parishes, or 81 per cent of all the parishes in the state. Thirty-three of the parishes produced oil and gas, 14 produced oil, and 5 produced solely gas. Tensas Parish in north Louisiana and Assumption Parish in south Louisiana formerly contained no producing fields but during 1943 joined the ranks of the producing parishes. Twenty-three new fields, including one rediscovery, were found during 1943-—a rate of discovery almost comparable to that of the preceding year. Eleven of these new discoveries were either gas or gas-condensate fields. Thus, the trend of development in finding new reserves was also comparable to that of 1942. Many reasons of considerable merit have been advanced to account for the discouraging lack of crude-oil reserves found during the past year. None are, however, completely satisfactory.

Jan 1, 1944

By J. Weertman

The paper of Gifkins and Snowden considers the interesting but difficult problem of determining the stress dependence of secondary (steady-state) creep at low stresses. These authors have concluded that at stresses below 250 psi (2 x 107 dynes per sq cm) the secondary creep rate of lead is proportional to the stress (viscous creep) and is not proportional to the stress raised to about a fifth power. The experimental data considered by them were obtained on tests conducted at room temperature and at 50°C. The lowest stress employed was 50 psi (3.5 X 106 dynes per sq cm). The authors pointed out the main difficulty in determining the stress dependence of creep at low stresses. The creep tests must be run for very long lengths of time. However they made no estimates of when an experimental creep rate determination must be rejected because it does not represent a true steady-state or minimum creep rate. In order to be certain that a creep curve is within the steady-state region, the total creep strain should be of the order of 0.1 to 0.2. For a creep test of a year's duration this requirement implies that a secondary creep rate smaller than about 10-3 per hr cannot be measured reliably. The corresponding creep rate for a 10-year test is 10-6 per hr. The creep rates of the tests that were considered by the authors to prove the existence of viscous creep were of the order of or less than 10-6 per hr. One can conclude reasonably that this data does not prove unambiguously that large strain steady-state creep rate of lead is proportional to the stress in the stress range of 50 to 250 psi (3.5 x 106 to 2 X 107 dynes per sq cm). Another technique can be used to obtain the stress dependence at low stress levels. The creep rate is a very sensitive function of temperature. The creep rate can be increased by very large amounts merely by increasing the temperature. We carried out steady-state creep tests on lead single crystals25 at temperatures up to 320°C. We were able to obtain creep rate data down to stresses as low as 35 psi (2.5 x 10' dynes per sq cm). Our smallest creep rate was 8 x 10-5 per hr. Thus we obtained large strain, steady-state creep rates to even lower stresses than were considered by Gifkins and Snowden. No evidence was seen for viscous creep. The creep rate was proportional to the stress raised to about a 4.5 power down to the lowest stresses. Since there is no reason to believe that changing the temperature should change the stress dependence of steady-state creep, we feel that large strain viscous creep does not occur in the stress range quoted by the authors for lead single crystals or large-grain polycrystalline samples of lead. This conclusion does not imply that viscous creep may nat occur in a lower stress range or in the same stress range for fine grain material or at creep strains very much smaller than 0.1. Support by the U.S. Office of Naval Research is acknowledged. Authors' Reply R. C. Gifkins and K. U. Snowden We thank Dr. Weertman for his discussion and although, as we hope to show, we do not agree with his reservations, we do concur in stressing the importance of ensuring that creep rates are reliably obtained. Dr. Weertman appears to be content to accept n = 1 for low stresses with fine-grained material but not for single crystals. We believe our results show that the former result cannot be accepted without also accepting the latter. We will also show that the probable errors in our minimum creep rates are insufficient to alter our conclusions, that the criterion proposed by Dr. Weertman is arbitrarily restrictive and his alternative experimental approach possibly invalid. 1) A principal result of our Fig. 1(a) is that n = 1 for polycrystalline specimens at room temperature and 50°C for stresses below -250 psi. There was evidence that crystal slip and grain boundary sliding contributed approximately equaily to the overall strain in this low-stress regime. This implies that either a) grain boundary sliding controls slip within the grains or b) both grain boundary sliding and crystal slip independently occur according to mechanisms which give n = 1. Alternative a does not seem acceptable, so we were forced to consider b. This led us to reexamine work on bicrystals by Strutt and Gifkins and plot curves Fig. l(b). Previously Strutt et al. (loc. cit.), had merged these points with others using the Zener-Holloman parameter and thus, we now believe, had been led to overlook the behavior where n = 1. Curves C and D in Fig. l(b) did appear to confirm the hypotheses that n = 1 for crystal slip at these low stresses and the sliding curve F was similarly of the expected form. It was comparatively easy to find a quantitative theory to account for n = 1 for sliding and the similarity of curves C and D to curve F (all obtained from the same set of specimens) led us to feel that the single-crystal curves were valid. 2) We believe the secondary creep rates for both the polycrystalline and single-crystal specimens to be in error by factors c2. In Fig. 6 creep curves for polycrystalline specimens of lead(1) and lead(II) are reproduced as curves a and b, respectively, and curve c is for a single crystal at 100 psi. It is clear that, although the attainment of secondary creep rate takes 2 years for a and 150 days for b, thereafter the curve is linear for periods of 7 and -1 year, respectively. The single crystal has a linear portion commencing after 20 and extending to 90 days. Creep extension was measured directly using a traveling microscope reading to 0.01 mm on gage lengths marked on the specimens; the gage lengths

Jan 1, 1968

By C. A. Heiland

THE investigations described were made on a portion of Clear Creek basin near Golden, Colo. (A portion of the area under survey is shown in Fig. 1. The photograph was taken in the vicinity of station No. 2 of Line II.) Three principal purposes were in the minds of the investigators: 1. To repeat with modern, more sensitive and more reliable instruments magnetometric placer investigations previously made. 2. To disprove the recently advanced theory that deposits of the glacial period have no pronounced magnetic effects. 3. To develop in detail the theory of the magnetic effects produced by placer deposits. Six years ago, the first magnetic observations were published, which proved that it is possible to locate gold-bearing channels with relatively crude instruments.1 Two years ago, K. C. Laylander published results obtained with similar instruments.2 The measurements of the latter were discussed by the senior author of this paper.3 At that time, however, the material available for such a discussion was somewhat scarce and not made with the most modern magnetic instruments, although very brilliant results were obtained. Therefore, the senior author felt that magnetic investigations should be made on very clear geologic conditions with the most modern instruments.

Jan 1, 1928

By V. T. BERNER

THIS apparatus was designed primarily to meet the demand for a quick, efficient stopping to seal off the burning area temporarily during a mine fire, but it can be used in any circumstance where an immediate brattice is required for ventilation control. In using the old style brattice, mine-rescue workers have found it difficult, in smoke-laden drifts and stopes, to erect an effective stopping with wooden frame and canvas. Stulls must first be cut to the proper length, the canvas tacked in place, and the numerous irregularities of the walls and back must be caulked. This operation requires the employment of axes, saws, and hammers, which cannot easily and safely be handled in dense smoke. The fire fighters have often been forced to abandon their brattice, unfinished, because of the rapid approach of the fire, or because of the exhausted sup- ply of oxygen in their breathing apparatus. It is neces-

Jan 1, 1930

The Honor Roll includes the names of all members of the Institute whom we know to be on active military duty at the date of its compilation, February 7, 1918. We are aware that there are many others of whose activities we have not been informed, and we shall be grateful for information as to any such omissions from the Roll. 1. MEMBERS ON ACTIVE MILITARY SERVICE Mail addressed to members on the first division of the Roll and sent to the office of the Institute Will be forwarded according to the best of our knowledge at the time. AARONS, J. BOYD, Capt., 4th Reinforcements, 11th Infantry, Australian Imperial Force. '05 ADAMS, HENRY, Capt Asst. to Dept. Engr., Northeastern Department. '02 AGNEW, FRANK VANS '04 ARBE, FREDERICK R., Capt 33d Engineers. '97 ALDER, ALFRED Engineers' Reserve Corps. '17 ALFORD, NEWELL G., Sgt., Bureau of War Risk Insurance, Headquarters 84th Division. '14 ALLEN, HEMAN H., Private Co. D., 8th Reserve Engineers. '17 AMBLER, HARRY A., Lieut 30th Infantry. '16 ANDERSON, ALEXANDER, Lieut Royal Garrison Artillery. '07 ANDERSON, GEORGE K., JR., See. C, 1st Co., 3d Officers' Training Camp. '17 ANDREWS, CLARENCE W., 1st Infantry Co., Officers' Training Camp, 83d Division. '13

Jan 1, 1923

HOW the Engineers' Memorial clock and carillon at Louvain has impressed the people of that city is indicated by the following letter sent by the Secretary of the University of Louvain to the Secretary of the United Engineering Society. We are still full of the memories of that splendid July 4, when we came into such .delightful contact with our American friends and more specially with the representation of the engineering societies of the United States. It was a great joy for all the members of the University to see those, American friends who have given to us such a splendid memorial in honor of- the brave men who fell in the Great War.

Jan 1, 1928

By Fred C. Bond

COMPRESSION TESTS THE standard method of determining the crushing resistance of rocks consists of crushing prepared shapes under slow compression, and expressing the ultimate crushing resistance at the load causing failure in pounds per square inch of crossectional area perpendicular to the crushing force, with the height approximately equal to the diameter. One-inch cubes or cylindrical drill cores are commonly used. Cubes and drill cores are cut by a high-speed steel disk with diamond dust embedded in the edges, and running under a water spray. Such a saw will cut one square inch or more of hard stone per minute. An oiled, spherical, swivel compression block of small diameter should be used to equalize the pressure. Each sample is crushed between sheets of cardboard or blotting paper extending about one-half inch beyond the edges of the stone. A cloth is wrapped around it to prevent dangerous explosive shattering. It is probably preferable to place the swivel block below the specimen, with either a rigid head or another swivel block above. Whatever the arrangement, the conditions should be selected that will develop the maximum crushing strength of the specimen, even though its top and bottom planes may not be precisely parallel. The cardboard pads may be dispensed with if the ends of the specimens are polished smooth. The use of lead pads was discontinued because of the observed tendency to split the material. The samples are weighed and measured before breaking, and the density is calculated. Cubes that contain bedding planes or veinlets are usually placed with these vertical and parallel to the crushing force, in order to develop the maximum resistance possible. A number of compression tests were made on Canadian ores, by Forrest Nagler, of the Allis-Chalmers Manufacturing Co., and are listed alphabetically in Table 1. These tests were made on one inch cubes or on diamond-drill cores approximately one inch in diameter and one inch long. The drill cores represent virgin rock, while the cubes may have been previously weakened by explosives. Compression tests have been made in the Allis-Chalmers Milwaukee Laboratory on a number of ores and other materials. These are listed alphabetically in Table 2. In test No. 1339, on limestone from the Hanna Coal Co., comparison was made between 2 by 2-in. diamond-drill core segments and one-inch cubes cut from the cores in the same strata. Results for the cylinders are tabulated directly below those for the cubes. The bedding planes were normal to the compressive force in breaking the cylinders and parallel in breaking the cubes, which accounts for the lower strength obtained from the cylinders. The percentage of net linear compression at the ultimate pressure was measured in test No. 1055 for Fontana TVA quartzite as 0.30 for cube A, and 0.37 for cube D.

Jan 1, 1946

By Frank M. Monroe, James R. Cost

The solubility of nitrogen in vanadium is determined from 275" to 575°C by measuring the height of the nitrogen internal friction peak of equilibrated V-N alloys. The proportionality constant at 275°C between the internal friction peak height (Q- 1) and the atom percent nitrogen in solution is found to be 0.095 per at. pct for nitrogen concentrations up to 0.8 at. pct. The heat of solution of the nitride in vanadium is 5500 cal per mole. The solubility of nitrogen in the Group V metals is discussed. LITTLE work has been performed on the vanadium-nitrogen terminal solid solution. Hahn1 found the solubility for nitrogen to be very small and reported the existence of a hexagonal phase of composition near that of V2N at the solubility limit. Rostoker and Yamarnoto2 reported the solubility to be at least 3.5 at. pct at the melting point and to be less than this value at 900°C. In addition, they reported from X-ray diffraction studies that nitrogen in solution produces tetragonality in the vanadium lattice. An X-ray study by Schonberg3 has confirmed the results of Hahn but indicated that the tetragonality observed by Rostoker and Yamamoto was due to the presence of oxygen in their specimens. Beatty4 has performed lattice parameter and hardness measurements on terminal solid solutions and found the upper limit of the solubility to be at least 0.66 at. pct N. No measurements have been made of the pressure-temperature-composition relationships (P-T-X) for the terminal solid solution. As a part of a research program on gas-metal equilibrium, an attempt was made to study the P-T-X relationships in the V-N system using both the internal friction and the gas equilibration methods which have been successful with the Nb(Cb)-N and Ta-N systems (see Ref. 5 for a review of this work). Extensive investigation, using the gas equilibration methods, showed this method not to be applicable with vanadium This was presumably due to the gettering action of vanadium sublimed on the walls of the Sieverts apparatus. Thus, the nitrogen pressure relationships with temperature and composition were not obtained. The internal friction methods were, however, found to be applicable, and the temperature-composition relationships are reported in this paper and compared with similar results for the Nb-N6 and Ta-N7 systems. The existence of a Snoek internal friction peak due to nitrogen in solution in vanadium has been clearly demonstrated. 8-10 Powers and Doyle found the peak to be at approximately 275°C for frequencies near 1 cps.8 In a subsequent paper10 they reported the proportionality constant at 275°C between the internal friction peak height (Q-1) and the concentration of ni- trogen in solution (in atom percent) as 0.06 per at. pct. The studies of Stanley and wert9 indicated qualitatively that the height of the Snoek peak decreased with aging at the peak temperature and thus suggested that internal friction methods were suitable for study of the solubility. EXPERIMENTAL METHOD The vanadium for this investigation was of particularly high purity. It was obtained from the Ames Laboratory of the U.S. Atomic Energy Commission, Ames, Iowa in the form of a 1/2-in. diam, three pass zone-refined ingot. The electrical resistivity ratio (p300ºk/p4ºk) was 160. The initial composition was determined as follows: Carbon 200 ppm Oxygen 150 ppm Chromium <50 pprn Iron 125 ppm Silicon <50 ppm Other metallic 100 pprn The initial vanadium ingot was fabricated to 30-mil wire by swaging and wire drawing without the need of intermediate annealing. Lengths of this wire were then further purified (particularly for oxygen) by outgassing at 10-6 torr at 1400°C for 4 hr. The outgassing treatment resulted in specimens with a bamboo grain structure and a lustrous appearance. Desired amounts of nitrogen were added to the outgassed wires in a Sieverts apparatus in which known amounts of nitrogen were equilibrated with the wire at 1300°C. Nitrogen concentrations were produced in the desired range from less than 1 to 10 at. pct N. Monitoring of the partial pressure of nitrogen in the Sieverts apparatus indicated that at 1300°C equilibrium between the nitrogen gas and the vanadium was obtained within 10 min. Relatively rapid cooling from the nitrogen addition temperature was obtained simply by turning off the specimen heating current and cooling to room temperature in the partial pressure of nitrogen. Internal friction measurements of wire specimens were made under forepump vacuum in a torsional pendulum at frequencies near 1 cps. The torsional pendulum was of low thermal inertia and was designed so that specimens could be heated both by a conventional tube furnace and by the joule heating of a separate current through the wire specimen." Use of a static atmosphere of helium gas as a quenching medium made it possible to cut the specimen current, rapidly cool the specimen to the measurement temperature, and make a measurement of the internal friction in less than 1 min. Because of the large solubility of vanadium for nitrogen, the internal friction peak heights were in some cases greater than Q-1 = 0.1. This high damping resulted in an estimated relative uncertainty in the damping measurements of approximately 10 pct. X-ray analyses made to identify the precipitated ni-

Jan 1, 1970

By W. P. Rawles

In the foreword by C. K. Leith, Chairman of The Mineral Inquiry, it is pointed out that the ordinary mineral production tables do not show the commercial control, and that some knowledge of the situation is desirable as a background for the consideration of problems involving mineral raw materials. The report consists principally of tables, accompanied by a brief text, giving the production and an analysis of the control, according to nationality, of 18 minerals: aluminum, chromite, copper, iron and steel, lead, manganese ore, mercury, molybdenum, nickel, nitrates, petroleum, potash, silver, sulfur, tin, tungsten, vanadium, and zinc. For the most part, the production figures for 1929 and the latest figures for reserves have been used. When feasible, the control has been shown at the various stages of production; mining, smelting and refining. American capital was dominant in the production of 10 mineral commodities, including six of the most important; British capital, in four instances; while Spanish, German, Chilean or Chinese interests cach led in the control of one. British, French, German, and Dutch capital occupied second place in the control of most of the important minerals. Between two-thirds and three-fourths of the world&apos;s mincral production is controlled by British and American capital.

Jan 1, 1934

By Charles Clayton

A study of the literature shows that the greater part of research work on annealing of cold-worked iron has been for the purpose of studying the effect on grain-size and properties other than hardness. No reference has been found of experimental work of the same nature as that explained in this short paper. The material used throughout was Vismera iron, an iron containing 0.03 carbon and made several years ago by the Inland Steel Co. One-half inch stock was cut into cylinders ¾ in. long. The cylinders were then compressed for 60 sec. in a Reihle testing machine under loads as indicated below: COMPRESSION, AVERAGE LENGTH, SERIES POUNDS INCHES 1 10,000 0.693 2 15,000 .599 3 20,000 .501 4 25,000 .426 5 30,000 .378 6 35,000 .351 7 40,000 .311 Fig. 1 shows these cylinders after compression. Each series con¬sisted of 17 specimens lettered 0, B, C, D, E, E:, G, H, I, J, K, L, M, N, P, Q, and R. One specimen of each series was reserved for study of the properties in the cold-worked condition. The other specimens were annealed in a Hump furnace for ½ hr. at the following temperatures:

Jan 2, 1926

GEORGE K. BURGESS,* Washington, D. C. (written discussiont).-Professor Sauveur refers to the International Aircraft Standards Board in terns that would indicate his non-familiarity with, the organization and the working of this Board which, of course, is excusable on account of Professor Sauveur&apos;s absence in Europe at the time. He implies .that the work of this Board was entirely dominated by American interests, whereas diametrically the opposite was the case. The Board, was organized for the purpose of facilitating purchase in the United States, on the basis of common specifications, by the Allied air, services in the United States, and the Board performed a very valuable service in unify-ing the specifications of Italy, Great Britain, France, Canada, and the United States for such purposes. The proceedings of the Board were car-ried out on the basis of unanimous agreement of the representatives of the five countries and all the members from each of the countries were technical specialists or, had the advice of technical assistants. It would be difficult to find an instance of greater unity of purpose, readiness to&apos; compromise, and efficient production than was shown by this Board, which produced seventy-eight specifications, in the preparation of which representative American manufacturers appeared before the Board.

Jan 12, 1919