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By H. C. Rickaby

BY August 1944 Canada expects to be shipping 56 percent hematite ore from its new Steep Rock iron mine, via Port Arthur on Lake Superior, to the steelmaking centers in Canada and the United States. This is indeed welcome news to steel men, especially if they operate open hearth furnaces, as the Steep Rock ore is a high-grade lump and will be valuable as charge and feed ore. But better news is the fact that this first big producer of high-grade hematite ore in Canada, since the exhaustion of the Helen mine in the Michipicoten area north of Lake Superior in 1918, has a proved ore body of 16,757,000 long tons and a probable ore body of 14,000,000 long tons, thus giving an over-all total of 30,757,000 long tons and assuring production for a number of years to come.

Jan 1, 1943

By Kim Beattie

IN spite of the fact that in 1944 Canada experienced a decline in production of all her leading base metals-nickel, zinc, lead, and copper; despite uncured headaches in the coal-mining industry; and cheerfully ignoring a still further drop in gold, the most valuable product of her mines, which had the lowest output of any year since 1931, the Canadian miner retains the traditional optimism of miners everywhere as he looks forward to the postwar period. Some factors should keep the Canadian mining industry from being too optimistic of the coming era of peace, but the fraternity generally holds that its confident attitude towards the future is based on sound reasons. The decline in production in the Canadian mining industry last year can be almost wholly attributed to the serious shortage of labor and the difficulty in obtaining transport and supplies in remote areas. Some falling off occurred in the demand for certain strategic metals, but the diversion of gold miners, especially, without replacements being obtainable, to direct war work or allied pursuits, was certainly the principal cause of the reduced output in 1944. But that is a situation which will right itself at the close of the conflict.

Jan 1, 1945

By Kenneth Schellinger

THE terms surface tension and surface energy are well known when applied to liquids and are generally described by referring to the excess energy of the air: liquid interface as a result of unsaturated molecular forces surrounding the surface molecules of the liquid due to the presence of the air phase on one side. Such unbalanced forces produce the familiar water droplet of spherical form and are generally summed up as a surface tension measured in dynes per centimeter which can be shown mathematically to be equal numerically to a corresponding surface energy expressed in ergs per square centimeter. A specific surface energy, however, is best thought of as the energy necessary to produce one unit, of new surface on a substance. Hence, in producing a bubble in a flotation cell the impeller must supply surface energy corresponding to the air: liquid interfacial area on the interior of the bubble. Inasmuch as it is relatively easy to extend or contract the surface of a liquid, there are a number of successful methods for liquid surface tension, or energy, measurement based upon surface deformation. This happy state of affairs does not, however, extend to solids, which are considered to possess surface energies for the same reasons as do liquids, i.e. because of unsaturated ionic bonds at the solid: gas interface. As in the case of the flotation cell producing surface on liquids as new bubbles, it takes energy to produce new surface on solids as new particles. As every mill man knows, this surface is produced on mineral solids in a grinding mill by the action of a tumbling mass of iron balls. But here so much energy usually is wasted by the inefficient action of these balls that a large amount of heat is generated, and the surface energy production may be easily confused with the energy necessary to produce this ineffective heat. The tumbling balls and fracturing minerals ultimately take their energy from a rather large electric motor. It has been variously estimated that from 10 to 20 pct'" only of this energy from the motor does not appear as heat and may be presumed to appear as surface energy on the min- erals present. Such a production of new surface on the mineral phases is accompanied, of course, by a size reduction that is inevitable as more and more mineral interior molecules become surface molecules by the fracture exposure. This size reduction of mineral particles, although the most obvious feature and perhaps the sole object of the milling operation, is from this energy viewpoint the outward manifestation of the production of surface energy only. Measurement of the characteristic surface energies of pure minerals and their various mixtures in ores would be a step towards understanding of the energetics of the commercial grinding operation. In addition, the characteristic surface energy of a mineral is probably a physical property specific for that mineral, and therefore, from a scientific standpoint, should be measured. It is interesting to note that, in contrast to the large body of work on the surface tensions of liquid systems and biological systems, the field of solid surface energies has been neglected. Prior to 1920 it is difficult to find more than one or two references to work on solid surface energies in Chemical Abstracts. Since 1920 such references number somewhat less than 100, while those on liquid systems are numbered in the thousands. Much of this apparent neglect of the field of solid surface energies (the term is intended to be somewhat inclusive at this point and refers both to the solid: gas, and the solid:liquid interface) is because of the lack of a reliable method of measurement rather than any lack of scientific curiosity. It was, and still is, difficult to produce new surface on a solid without the simultaneous production of interior changes in the same solid which may consume part of the energy used. The extension in the surface area can be measured, but the interior crystal-

Jan 1, 1953

By Kenneth Schellinger

THE terms surface tension and surface energy are well known when applied to liquids and are generally described by referring to the excess energy of the air: liquid interface as a result of unsaturated molecular forces surrounding the surface molecules of the liquid due to the presence of the air phase on one side. Such unbalanced forces produce the familiar water droplet of spherical form and are generally summed up as a surface tension measured in dynes per centimeter which can be shown mathematically to be equal numerically to a corresponding surface energy expressed in ergs per square centimeter. A specific surface energy, however, is best thought of as the energy necessary to produce one unit, of new surface on a substance. Hence, in producing a bubble in a flotation cell the impeller must supply surface energy corresponding to the air: liquid interfacial area on the interior of the bubble. Inasmuch as it is relatively easy to extend or contract the surface of a liquid, there are a number of successful methods for liquid surface tension, or energy, measurement based upon surface deformation. This happy state of affairs does not, however, extend to solids, which are considered to possess surface energies for the same reasons as do liquids, i.e. because of unsaturated ionic bonds at the solid: gas interface. As in the case of the flotation cell producing surface on liquids as new bubbles, it takes energy to produce new surface on solids as new particles. As every mill man knows, this surface is produced on mineral solids in a grinding mill by the action of a tumbling mass of iron balls. But here so much energy usually is wasted by the inefficient action of these balls that a large amount of heat is generated, and the surface energy production may be easily confused with the energy necessary to produce this ineffective heat. The tumbling balls and fracturing minerals ultimately take their energy from a rather large electric motor. It has been variously estimated that from 10 to 20 pct'" only of this energy from the motor does not appear as heat and may be presumed to appear as surface energy on the min- erals present. Such a production of new surface on the mineral phases is accompanied, of course, by a size reduction that is inevitable as more and more mineral interior molecules become surface molecules by the fracture exposure. This size reduction of mineral particles, although the most obvious feature and perhaps the sole object of the milling operation, is from this energy viewpoint the outward manifestation of the production of surface energy only. Measurement of the characteristic surface energies of pure minerals and their various mixtures in ores would be a step towards understanding of the energetics of the commercial grinding operation. In addition, the characteristic surface energy of a mineral is probably a physical property specific for that mineral, and therefore, from a scientific standpoint, should be measured. It is interesting to note that, in contrast to the large body of work on the surface tensions of liquid systems and biological systems, the field of solid surface energies has been neglected. Prior to 1920 it is difficult to find more than one or two references to work on solid surface energies in Chemical Abstracts. Since 1920 such references number somewhat less than 100, while those on liquid systems are numbered in the thousands. Much of this apparent neglect of the field of solid surface energies (the term is intended to be somewhat inclusive at this point and refers both to the solid: gas, and the solid:liquid interface) is because of the lack of a reliable method of measurement rather than any lack of scientific curiosity. It was, and still is, difficult to produce new surface on a solid without the simultaneous production of interior changes in the same solid which may consume part of the energy used. The extension in the surface area can be measured, but the interior crystal-

Jan 1, 1953

By Tuncel M. Yegulalp, Peter G. Zambas

In planning an underground room-and-pillar mine, the selection of the shaft or portal location and the orientation of the main haulage arteries is of paramount importance, particularly in view of the high dependence of the cost of truck haulage on the proper definition of these parameters. In an effort to facilitate this selection a computer program was written which, by relating the truck characteristics to the areal configuration of the property or ore body, derives the volume-weighted total fuel and time requirements for hauling ore from every panel within the property to a specified portal or shaft location through a predetermined gridwork of haulage drifts. By varying the size and orientation of the gridwork and the location of the portal or shaft access, an infinite number of configurations can be investigated. The results of this analysis can be plotted to indicate the optimum conditions.

Jan 1, 1974

By R. E. HORE, J. B. Tyrrell

IN the vicinity of Kirkland Lake, northern Ontario, several gold mines are producing, and three are at present being operated very profitably. At these three mines and on the adjoining properties east and west of them there have been important developments during the past year, and additional equipment has been installed to permit a large increase in output. At the end of 1924 the total production amounted to $13,688,600. For the year 1926 the production is estimated at about $19,000,000, and during 1926 the output should be much greater than that of 1925. The mines which are being operated most profitably and are producing a large part of the ore now being milled are the Wright-Hargreaves, Lake Shore and Teck-Hughes. Others which have contributed smaller amounts are the Tough-Oakes-Burnside and the Kirk- land Lake Gold mines.

Jan 1, 1926

By Elliot P. Rexford

B. C. Burgess-—Prior to hearing this paper presented at the San Francisco meeting, I travelled by car from Yuma, Ariz., across south-central California and up through the San Joaquin Valley. After hearing the paper I returned by the coast route to San Diego then along the Mexican border to Yuma. The striking feature of these trips, related to this paper, was the dry river and creek beds at a time of year not the dry season. Contrasted with this was the wasteful use of water in irrigation canals and laterals. Poland says "at least 90 pct of the ground water pumped is used for irrigation." That being the case, it would appear that first consideration should be given to conservation of this use. Probably a small part of this is actually reaching the plants. Some measure of this loss between pump and crops would be revealing. Methods that might be employed to reduce this loss are pipe lines and spraying of some crops such as the banana planters are using in Central America. Another idea which might be investigated is to line canals and ditches with some water-repelling mineral like pyro-phyllite. Perhaps a comparatively thin sprayed-on

Jan 1, 1951

By Elliot P. Rexford

B. C. Burgess-—Prior to hearing this paper presented at the San Francisco meeting, I travelled by car from Yuma, Ariz., across south-central California and up through the San Joaquin Valley. After hearing the paper I returned by the coast route to San Diego then along the Mexican border to Yuma. The striking feature of these trips, related to this paper, was the dry river and creek beds at a time of year not the dry season. Contrasted with this was the wasteful use of water in irrigation canals and laterals. Poland says "at least 90 pct of the ground water pumped is used for irrigation." That being the case, it would appear that first consideration should be given to conservation of this use. Probably a small part of this is actually reaching the plants. Some measure of this loss between pump and crops would be revealing. Methods that might be employed to reduce this loss are pipe lines and spraying of some crops such as the banana planters are using in Central America. Another idea which might be investigated is to line canals and ditches with some water-repelling mineral like pyro-phyllite. Perhaps a comparatively thin sprayed-on

Jan 1, 1951

EUGENE WESLEY SHAW,* Washington, D. C. (written discussion ?).-Studies of the probable future production of oil wells and fields-particularly those in the nature of the recent work by Lewis and Beal, having the object of increasing the percentage of recovery-rank, in both practical and theoretic value, very high, if indeed they do not outrank all other petroleum investigations except structural surveys. Even such surveys, although saving untold millions that might have been spent in prospecting unpromising territory, may have less ultimate value than generally supposed, for it may perhaps be argued that much if not most of the condemned territory will sooner or later be tested-some is already productive-and the most that can be rightly claimed is the recovery of cream first; also that the consumption of the richest portions first cannot be extenuated, as it might with some resources, on the ground that if the best is not taken now it will deteriorate.

Jan 5, 1918

By H. D. Outmans

The author applies the theory of hydrodynamic stability to fluid flow in porous media and concludes that the displacement of miscible liquids is stable if the stability coefficient, as defined by Eq. 19.2 or Eq. 27.0, is positive. The conclusion is invalid, however, since it is based on a faulty argument. To demonstrate this, the reader is referred to Eqs. 4.1 through 4.5 of the paper which describe, in differential form, the first-order disturbances c, u, v, w and p. In these same equations, cx, cz, gl, g3 and are functions of the stable concentration c. This concentration c is known and depends on x, z and t (the author assumes cy = 0). It follows that cx, cz, gl, g3 and µ are also functions of x, z and t. With this in mind, we turn to Eqs. 8.1 through 8.5 which were derived from Eqs. 4.1 through 4.5 by substituting Eq. 6.0. The significance of this substitution is that the author thereby limits the solutions of Eqs. 4.1 through 4.5 to equations of the form of Eq. 6.0. Eqs. 8.1 through 8.5 represent an infinite linear system with five unknowns: c, u, v, w and p. The coefficients cx, cz, gl, g3 and µ in this system are known at each point and at each instant; the coefficients containing derivatives of f are unknown. If this infinite linear system in c, u, v, w and p is to have a nontrivial solution, then it is indeed necessary (as the author states) that the determinant of the coefficient matrix of Eqs. 8.1 through 8.5, i.e., ( A 1, be equal to zero. This condition, however, is not sufficient. A non-trivial solution exists if, and only if, the rank of the coefficient matrix of the entire infinite system is smaller than five. In other words. all minors of order five must vanish and only if all the coefficients in Eqs. 8.1 through 8.5 are constant is this equivalent to the condition |A| =0. Constant coefficients means that gl, g3 and µ, for instance, are constant; and, since they depend on c it follows that c must be constant. We conclude that the condition I A I = 0, on which the author bases his calculations, is necessary and sufficient for a nontrivial solution only if the concentration c is constant. In other words, the author does not investigate the stability of a miscible displacement but, rather, only the stability of the flow of a homogeneous liquid. Using the initial condition and the fact that the coefficients are constant, we find

By G. Aertsen

THE CHAIRMAN (HENRY D. HIBBARD, Plainfield, N. J).-This excellent paper fills a gap in our Transactions and is most acceptable. In the early days another way of casting tire ingots, sometimes called cheeses, because of their shape, was to use a 22-gage sheet-iron cylindrical can for each ingot of the proper size to give the weight desired. These cans were bottom cast in groups, usually of four, each can being surrounded by a heavy iron ring somewhat taller than itself the top of the can being covered by a circular cast-iron plate having a small conical riser in the center, about 2 ½ in. in diameter at the bottom and 10 in. high. The top plate was clamped down to resist the upward pressure of the fluid metal and the space between the can and the outer ring, usually about 2 in. wide, was filled with dry sand. The riser permitted the escape of some of the air displaced by the steel and also increased the pressure in the steel when the mold was filled, and so diminished somewhat the tendency for gas holes to form. But little was known of segregation and pipe in those days, though the center of an ingot was understood to be the worst part, and it was separated in part in the disk which was punched out in perforating the ingot. This disk was about 8 in. in diameter and from ¾ to 2 in. thick, the variation in thickness being to rectify the weight. When an ingot was too -heavy, a thicker disk-was made by not driving the punch in quite as far as when the ingot-weight was right. Then the bloom was turned over and the punch driven in on the other side, which finished the punching and detached the disk. The tire bloom was then" becked" and later reheated and rolled as described in the paper. The forging was done with a 10-ton double-acting steam hammer. The steel generally speaking had lower carbon, from 0.45 to 0.55 per cent., than tires today have, and the tires were smaller, the most common size of ingot weighing 1,060 lb. each. BRADLEY STOUGHTON, New York, N. Y.-This paper was specially requested by the Iron and Steel Committee, because that Committee thought so important an industry should have its history written by one who was familiar with it, and before he had forgotten, or all the rest of the world had forgotten, its early stages. Mr. Aertsen has said that it is not an exhaustive research. I think it would not be any different if it were an exhaustive research, because our library made a careful attempt to find some written light on the history of these tires, but very little was found.

Jan 4, 1917

By Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Knox, Montague, Wichita, and Wil-barger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay Counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. Developments during 1940 The encouraging outcome of exploration and development in Montague and Cooke Counties and generally greater activity throughout the district resulted in the drilling of some 1700 wells during 1940, about 350 more wells than were drilled in 1939. Approximately 1250 of these tests were completed as oil wells. Production likewise increased during I940 to the extent of 8 million barrels more than the 25 1/2 million barrels produced in 1939. In spite of this large increase in production, known oil reserves again increased substantially. As is usually characteristic of this district, the new reserves were from a large number of fields, none of which were of such magnitude as to be important to the oil industry. Nevertheless, the Fargo field, Wilbarger County, deserves mention as one of the more important discoveries in this district during 1940. Following seismic surveys, the hmerada Petroleum Corporation located its No. I Goodpasture in sec. 35, block IS, H. and T. C. R. R. Co. survey, and drilled it to a total depth of 6717 ft. This well was completed in July 1940 through perforations in the casing from a pay between 3230 and 3252 ft. for an initial production of 241.5 bbl. on an 8-hr. pumping test. Other potential producing horizons were found in the Pennsyl-vanian at depths of 3960 to 3995 ft., 4208 to 11.234 ft., 4407 to 4422 ft., and in the Ordovician at 6300 ft. Wells completed to date in the several Pennsylvanian horizons have an average daily potential of 600 bbl. of oil. Although no wells have yet been completed in the Ellenburger dolomite (Ordovician), the discovery well swabbed I5 bbl. per hour from this formation before plugging back for completion in an upper horizon.

Jan 1, 1941

By Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Knox, Montague, Wichita, and Wil-barger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay Counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. Developments during 1940 The encouraging outcome of exploration and development in Montague and Cooke Counties and generally greater activity throughout the district resulted in the drilling of some 1700 wells during 1940, about 350 more wells than were drilled in 1939. Approximately 1250 of these tests were completed as oil wells. Production likewise increased during I940 to the extent of 8 million barrels more than the 25 1/2 million barrels produced in 1939. In spite of this large increase in production, known oil reserves again increased substantially. As is usually characteristic of this district, the new reserves were from a large number of fields, none of which were of such magnitude as to be important to the oil industry. Nevertheless, the Fargo field, Wilbarger County, deserves mention as one of the more important discoveries in this district during 1940. Following seismic surveys, the hmerada Petroleum Corporation located its No. I Goodpasture in sec. 35, block IS, H. and T. C. R. R. Co. survey, and drilled it to a total depth of 6717 ft. This well was completed in July 1940 through perforations in the casing from a pay between 3230 and 3252 ft. for an initial production of 241.5 bbl. on an 8-hr. pumping test. Other potential producing horizons were found in the Pennsyl-vanian at depths of 3960 to 3995 ft., 4208 to 11.234 ft., 4407 to 4422 ft., and in the Ordovician at 6300 ft. Wells completed to date in the several Pennsylvanian horizons have an average daily potential of 600 bbl. of oil. Although no wells have yet been completed in the Ellenburger dolomite (Ordovician), the discovery well swabbed I5 bbl. per hour from this formation before plugging back for completion in an upper horizon.

Jan 1, 1941

By R. D. Fisher, A. G. Metcalfe, F. A. Crossley

AN investigation of the application of magnetic stirring to the consumable arc melting of aluminum and nickel demonstrated that grain refinement could be obtained when there was sufficient stirring force. Also, it was found that grain refinement could be obtained in aluminum by alternately reversing the polarity of the current through the magnetic stirring coil. The effect of the latter was to periodically reverse the direction of rotation of the molten metal.' Because of their promise, these findings were applied to conventionally cast aluminum. Shortly after this work was begun, Kondic2 reported experiments in which aluminum cast with 40° C (72° F) of superheat exhibited a grain size of 10 to 20 grains per cm2. When interrupted rotation was applied during solidification by mechanical means, a grain size of 800 to 1000 grains per cm2 was obtained. Magnetic Stirring Applied to Conventional Casting— The applicability of magnetic stirring to producing grain refinement in conventionally cast metal was evaluated in the following way. Three pounds of aluminum were cast into a clay-bonded graphite mold. The mold was surrounded by a magnetic stirring coil of 1000 turns. A direct current of 200 amp was passed through the casting by means of a graphite electrode which was immersed from the top. A current of 5 amp was passed through the stirring coil. The aluminum (1100 or 25) was superheated to 1600° F (871° C) and fluxed by passing chlorine gas through the melt for 2 min prior to casting. Two additional castings were made for comparison: 1) a conventional casting of metal superheated to 1600° F and 2) a similar casting through which 200-amp current was passed during solidification, but without current in the magnetic coil. Macrosections of these three ingots are shown in Fig. 1. Very remarkable grain refinement resulted in the magnetically stirred casting. It may be noted that the casting through which 200-amp current was passed has a coarser structure than the conventional casting. It would appear that this is due to the additional heat input generated by the current to the former casting. Mechanical Rotation Applied to Conventional Casting—A casting temperature of 1600° F was used throughout. Some 1 1/2 -lb castings rotated at 150 rpm were predominantly columnar with small areas of coarse, equiaxed grains close to the lower mold wall. Following these, a series of 3-lb castings was made. Macrosections of these ingots are shown in Fig. 2. The imposed rotational speed was 250 rpm. Turbulence or acceleration in the solidifying liquid was the significant factor. Fine grain size resulted in the material solidified during the period of acceleration of the liquid to the imposed rotational speed. When uniform rotational motion was achieved, the grain structure reverted to columnar. The final casting shown in the lower right-

Jan 1, 1962

By K. Sassa, I. Ito

The dynamic principal stresses induced within rock by an explosion under con fined conditions are analyzed for the case of blasting with one free face by applying the values of measured radial displacement, particle velocity and so on to equations derived from the theory of elasticity. The dynamic stresses on the free face are also calculated from the strain measured by wire strain gauges affixed on the free face. Some results obtained are briefly: 1) The maximum stress on the free face appeared at the intersection between the free face and the burden, and its magnitude was about twice as large as the magnitude of the tangential tensile stress imparted by the incident stress wave within the range related to the breakage by blasting. 2) The maximum value of the compressive stress near the free face was decreased due to the existence of the free face, while that of the tensile stress was increased. 3) At any point near the free face, the directions of the principal stresses in the r? plane using spherical coordinates with the origin at the center of the spherical charge, changed with time except in the direction of the burden. However, at another point near the explosion point where the principal stresses were mainly those stresses caused by the initial longitudinal wave, the directions of the principal stresses coincided with those of the coordinate used. 4) The maximum value of the tensile stress in the F direction was larger than those in the re plane at and near the free face. 5) The tensile stress caused by the Hopkinson effect appeared only near the burden. 6) It is presumed from the results of stress analysis that radial cracks will be produced in the rock mass near an explosion point, but with the approach of the free face, the directions of cracks curve towards a direction parallel to the free face. INTRODUCTION In order to investigate the mechanism of rock breakage by blasting, it is considered to be very im- portant to know how the stresses are generated and distributed within the rock by explosion of a confined charge. As part of a research program concerning the mechanism of rock breakage by blasting, the authors have already published papers on the detonation pressure produced at the inner surface of the charge hole1 and on the behavior of the dynamic stresses within rock caused by an explosion in the case where no free face existed.' In this study the dynamic stresses on and near the free face have been investigated for the case of blasting with one free face. The mechanism of rock breakage in blasting is discussed in the light of these studies.

Jan 1, 1967

By A. K. Mukherjee, J. E. Dorn

A modified Peierls model is Presented for the rationalization of the asymmetric plastic behavior of single crystals of bcc metals. The model assumes that the asymmetry of slip arises from a tendency toward asymnetric splitting of the a/2[111] screw dislocation. The approach differs from former theories however insofar as it assumes that the splitting is so minor ttut only the core energy is modified and that no real partial dislocations exist. As a consequence, the concepts of a line energy of a partial dislocation, interaction between partial dislocations, constriction energies, and stacking fault energies are not invoked. Instead the present analysis is based on a specialization of the Peierls mechanism which assumes an asymmetric dislocation core which is modified by the effective stress and permits cross slip. The theoretical predictions on the stress-temperature -strain rate and orientation relationship agree qualitatively with the limited experimental data that are currently available. Additional experimental work over wider ranges of conditions is suggested to provide more complete evaluation of the possible validity of this theory. RECENT experimental investigations on the low-temperature thermally activated deformation of bcc metals have confirmed the existence of several unique orientation effects. These will be described with the aid of the standard stereographic projection shown in Fig. 1. If slip were determined exclusively by crystal symmetry, the deformation characteristics would be symmetrical about X; = 0 and independent of whether the specimen were subjected to a tension or a compression stress, regardless of what combinations of slip planes might be operative. Experiments, however, reveal that neither of these symmetry based predictions are valid. A schematic representation of the commonly observed asymmetry of both the yield stress and the plane of slip is shown in Fig. 2. A reversal of the direction of stressing results in an inversion of the asvmmetric behavior. 1) Asymmetry bf Yielding. A detailed investigation on the asymmetric yielding in an Fe-2.7 pct Si alloy was repoEted by Tabka, Tikeuchi, and Furubayashi,1 Similar trends have been observed by Keh and Nakada on iron,' Stein on molybdenum,3 Bowen, Christian, and Taylor4 on columbium, Sherwood, Guiu, Kim, and pratt5 on Ta, Cb, and Mo. The degree of asymmetry not only depends on the atomic number and alloying but, in all cases that have been examined, it also increases with a decrease in the test temperature. 2) Asymmetry of the Slip Plane. Asymmetric $I-~: curves of the type shown in Fig. 2 have been found for several Fe-Si alloys6-8,1 and columbium.4 There is general agre_ement that near X: = 30 deg slip occurs by the [111](211) mode so that ?1 = 30 deg. As X; decreases it appears that [111](211) to [111](101) cross slip takes place leading to slip band traces on intermediate planes. And as xi approaches 0 deg, sharp

Jan 1, 1970

By Kenneth Seaver

Discussion of the paper of KENNETH SEAVER presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 1913 .to 1927. J. W. RICHARDS, South Bethlehem, Pa.-This paper concerns a very large industry, and an important detail in that industry. Within sight of where I live in Bethlehem, Pa., are coke works in which $2,500,000 was lost by the use of improper bricks in the coke ovens. This was the fundamental reason of the failure of the plant. The old ovens have all been torn out and replaced by new ovens built of proper bricks. This may emphasize the commercial importance of this subject. When speaking about coke-oven brick, the first thing that comes to my mind is how important it would he if it were possible to. get a brick of better heat conductivity. The heat for coking coal has to go through the thickness of the brick. The silica brick used has low heat conductivity as compared with some other refractories; magnesite brick probably has four times its heat conductivity. The coke oven needs bricks of high heat conductivity. Any process which would increase the heat conductivity of silica brick would undoubtedly shorten the coking process.

Jan 12, 1915

By H. T. Kennedy

The fact that intrusion of water into oil wells can be prevented by treating the sand adjacent to the well seems to have been only recently recognized. Swan1 mentions the process of solidifying naphthalene in strata. R. Van A. Mills2 recommends the use of materials such as sodium silicate and sodium carbonate, which react with oil-field water to form solid plugging agents. When a well is drilled in a new field the oil sands are found essentially devoid of water (Fig. 1). Unless a completely impermeable break exists over wide areas in the field, no water is found above the lower limit of the oil zone and no oil is found below the upper limit of the water zone. After considerable oil has been taken from the well, however, it is almost universal experience that water intrusion occurs. This intrusion may be of two kinds. The water may follow a path parallel to the bedding planes of the producing formation through loose streaks in the pay sand, as shown in Fig. 2, or the water level of the field may rise and enter the well by coning (Fig. 3). Water entering from the side is called "edge water," and that coming in from the bottom is called "bottom water.'' Effectiveness of any method for shutting off water depends not only on the effective treatment of the sand adjacent to the well but on

Jan 1, 1936

By H. T. Kennedy

The fact that intrusion of water into oil wells can be prevented by treating the sand adjacent to the well seems to have been only recently recognized. Swan1 mentions the process of solidifying naphthalene in strata. R. Van A. Mills2 recommends the use of materials such as sodium silicate and sodium carbonate, which react with oil-field water to form solid plugging agents. When a well is drilled in a new field the oil sands are found essentially devoid of water (Fig. 1). Unless a completely impermeable break exists over wide areas in the field, no water is found above the lower limit of the oil zone and no oil is found below the upper limit of the water zone. After considerable oil has been taken from the well, however, it is almost universal experience that water intrusion occurs. This intrusion may be of two kinds. The water may follow a path parallel to the bedding planes of the producing formation through loose streaks in the pay sand, as shown in Fig. 2, or the water level of the field may rise and enter the well by coning (Fig. 3). Water entering from the side is called "edge water," and that coming in from the bottom is called "bottom water.'' Effectiveness of any method for shutting off water depends not only on the effective treatment of the sand adjacent to the well but on

Jan 1, 1936

By Walter Rose

Experimentation which measures differences in pressure across the interfaces of immiscible fluids in the interstitial spaces of porous media may be termed "capillary pressure experimentation". In the literature of petroleum technology since 1941 there have appeared twelve papers popularizing capillary pressure concepts and developing applications of these concepts for the solution of problems of practical reservoir engineering importance, such as the determination of connate water, fluid distribution. in transition zones, reservoir rock textural properties, and oil recovery from petroleum reservoirs. Although a review of the literature would be justified at this time in order to reconcile the conflicting viewpoints which are contained in the cited papers, the object of this note will be of more limited scope. It is believed that the recent paper of Muskat alls sufficient attention to many of the uncertainties which arise upon examination of the published literature. such that until satisfactory counter-proposals can be made it will serve our purpose only to mention some other like uncertainties. This will emphasize further the need confronting petroleum technologists to re. consider and reformulate the application possibilities of capillary pressure experimentation. In particular, I sug- gest that we examine the thesis that capillary pressure experimentation as above defined can lead to measurements reflecting the recovery of oil from petroleum reservoirs, as was proposed first" by Amyx and Yuster and was first reduced to practice by the experimentation of Welge . In fact. I shall deal exclusively with the Welge papers since it is the principle one on this subject which has appeared to date. I shall attempt to show that the possibility of describing oil recovery features in terms of capillary pressure phenomena has not been established entirely. The Welge paper was a pioneering effort to evaluate this recovery application possibility. P. P. Reichertz' comments on the Welge paper state that non-wetting phase discontinuities are developed occasionally in the Welge experiment, and restate Muskat's argument that discontinuous fluid elements (partially saturating the interstices of porous media which are elsewhere saturated with some other immiscible phase or phases) are not subject to the requirements of hydrostatic equilibrium. It is the purpose of my comment to show that it is unnecessary to make Reichertz' postulation regarding non-wetting phase discontinuities (however valid) when it is desired to criticize Welge's theoretical treatment of his problem. It can be shown that Welge's method of measuring values for ''capillary pressure" is invalid in many instances of application, such that his reported curves of capillary pressure Versus fluid saturation often have no physical meaning, even throughout the interval of fluid saturation where it might be otherwise suspected that no phase discontinuities occur. By considering established principles of capillary pressure experimentation it can be shown that the pressure difference experimentally observed between wetting and non-wetting fluid phases which are contained in external reservoirs will reflect on the capillary pressure difference at the interfaces of contact between these phases only when the following conditions are satisfied: (a) There shall be a balance between the opposing forces of gravity and capillarity, as obtains under conditions of hydrostatic equilibrium when the positions of the interfaces of contact become fixed in pore spaces of certain geometry (b) The wetting and non-wetting fluids within the interstitial spaces shall everywhere be continuous with the external wetting phase reservoir and the external non-wetting phase reservoir, respectively. It will become apparent immediately that in any instance when a greater pressure is recorded in the external wetting phase reservoir than in the external non-wetting phase reservoir, one may establish either that static equilibrium has not been attained or that discontinuities in one or more of the fluids have been developed. This is because the pressure otherwiee is always gereatest in the non-wetting phase at each static interstitial interface of contact with the wetting phase. such that the externally measured pressure in the non-wetting phase likewise must be greatest if the above conditions are to be satisfied.

Jan 1, 1949