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By AIME AIME

AN outstanding session of the Annual February Meeting was one held under the joint auspices of several groups on Tuesday afternoon, Feb. 22, as a symposium on the question of preserving peace in the postwar era through the control of the supply of sundry minerals vital to the Axis nations. D. H. McLaughlin and R. C. Allen were associate chairmen. And C.K. Leith led the discussion.

Jan 1, 1944

By Donald Ingvoldstad, Harold E. Lee

At Bunker Hill the original charge storage and preparation system was installed in 1917 to accommodate lead-silver gravity mill products. Only minor tonnages of wet fines such as vanner and flotation concentrates were received. Charge flux and diluent requirements were provided by an ample supply of siderite middlings and coarse limerock. While oversize material was crushed through Y4-in., the use of roll crushers in series resulted in a more or less granular, free-running charge of adequate porosity. Under such conditions, receipts could be proportioned directly from receiving bins, and suitable blending was obtained by passing the resultant layered composite through a small Stedman disintegrator. This elementary system served well for production and smelting of an extremely lead-rich sinter, in the low column blast furnace. Here sinter physical quality is less critical, and appreciable quantities of raw flux and oxidized ore may be charged directly to the blast furnace without seriously impairing furnace capacity.

Oct 1, 1956

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 Dever C. Ashmead

FRom time to time metal-mine engineers have inquired why anthracitc mines and their preparators are rarely operated on the two or three-shift basis. The subject may be approached as affecting: labor, development, the underground workers, the preparator, the outside workers, capital, the supply account, power consumption, the storage of coal over various shifts, railroad car supply, and the market. Labor From the start, the adoption of a plan of three full-shift operations in a day would cause difficulty with the colliery employees, for they have never worked on that plan and would show their resentment by suspending work. Even if they could be induced to work according to this schedule they would not be as efficient, for they would be working more or less unwillingly at hours at which they are accustomed to rest. Operation on a three-shift basis would necessitate triple manning of each working place, and dissensions would arise between the men, for each shift would claim that the preceding shift had taken undue advantage and had not left as favorable conditions as it had found. To obviate these disputes it might be [necessary to let out the work to a contractor, who would hire his helpers to mine out the chamber, or breast. The state mining law requires that a miner be put in charge of each working place. To conform with this provision he would have to hire three helpers and two miners to mine the breast. The labor unions have been trying to abolish the subcontractor in mine work and any method of working that would cause his return, however innocent in purpose, would result in labor disturbances. It might be possible to form partnerships of three miners working a place together, but these men would be quite likely to have frequent dissensions as to the proportion of work performed by each shift. Only

Jan 1, 1923

By Dever C. Ashmead

FRom time to time metal-mine engineers have inquired why anthracitc mines and their preparators are rarely operated on the two or three-shift basis. The subject may be approached as affecting: labor, development, the underground workers, the preparator, the outside workers, capital, the supply account, power consumption, the storage of coal over various shifts, railroad car supply, and the market. Labor From the start, the adoption of a plan of three full-shift operations in a day would cause difficulty with the colliery employees, for they have never worked on that plan and would show their resentment by suspending work. Even if they could be induced to work according to this schedule they would not be as efficient, for they would be working more or less unwillingly at hours at which they are accustomed to rest. Operation on a three-shift basis would necessitate triple manning of each working place, and dissensions would arise between the men, for each shift would claim that the preceding shift had taken undue advantage and had not left as favorable conditions as it had found. To obviate these disputes it might be [necessary to let out the work to a contractor, who would hire his helpers to mine out the chamber, or breast. The state mining law requires that a miner be put in charge of each working place. To conform with this provision he would have to hire three helpers and two miners to mine the breast. The labor unions have been trying to abolish the subcontractor in mine work and any method of working that would cause his return, however innocent in purpose, would result in labor disturbances. It might be possible to form partnerships of three miners working a place together, but these men would be quite likely to have frequent dissensions as to the proportion of work performed by each shift. Only

Jan 1, 1923

By Clement K. Chase, F. Milton Lewis, Roshan B. Bhappu

In this paper an attempt has been made to review the cost trends in producing copper by conventional milling, smelting and hydrometallurgical means during the last five years. The primary objectives of this cost analysis are to provide a base for future projections as well as to indicate which cost items are more volatile in their influence on overall cost of producing copper.

Jan 1, 1979

By J. B. Rather

The use of sulfuric acid in refining illuminating oils antedates the beginning of the petroleum industry in America by many years. It was used as early as 1792 by Tower in refining "coal oil" in the British Isles, and by 1860 there were 53 refineries in the United States manufacturing "coal oil," most of them using sulfuric acid as a refining agent. Following the completion of the Drake well in 1859, many of the "coal oil" refiners began to use petroleum for manufacturing illuminating oil, and their methods and equipment were adapted so far as possible to this new raw material. The value of sulfuric acid in refining L'coal oil" having been established, this reagent was immediately tried and found to be satisfactory in refining petroleum. Notwithstanding the tremendous advances in petroleum technology since that time, sulfuric acid remains today the most valuable and most widely used means for refining petroleum products. Early Methods of Disposal of Acid Sludge With the almost immediate expansion of the petrolrum industry came the problem of disposing of the acid sludge produced in the refining operations. While in 1859, the year of the discovery of the Drake well, a patent was granted for sludge separation and separated acid concrntration, most of the earlier refiners, and rnany of their successors, felt that separation and recovery of spent acid was uneconomical. Accordingly, many of then) disposed of the sludge in any way that seemed expedient nt the time. It was huricd in the refinery grounds, harged and tlurnped at sea, run into neighboring streams, or dumped into sewers. Some optimists carted it to open pits in the hope that it would eithcr sink into the ground or evaporate. Not so many years ago, the superintendent of nn eastern refinery, who was using the open-pit method of disposal, lost, a sludge cart, with horse attached, in such a pit. The horse was recovred almost immediately, but its availability for further use was reduced to zero by the loss of its hair.

Jan 1, 1928

By Roy E. Thomas

Soon after the Waelz p1an.t for the fire concentration of low-grade zinc ores was put into operation in the early part of 1929 at Katowice, it was found that the conveyor equipment for transporting the hot residue from the furnace dust chambers was inadequate. Hand tramming with water cooling was used for a time, but that method was injurious to the workmen as well as costly. The problem was to find some practical mechanical means of conveying flue dust at temperatures of from 450" to 600°C. as it was drawn from the dust chambers. After considerable preliminary investigation it was decided to install pneumatic equipment for conveying the hot materials to a central mixing plant, where it would be mixed with slime and from which it would be returned to the furnace feed hoppers. The first pnenmatic equipment was installed in 1930, and has been in successful operation since that time. The pneumatic method of transportation has shown a considerable saving in operating costs over the former methods of dust handling and a decided improvement in working and hygienic conditions at the plant, through the elimination of the dust hazard. Additional pneumatic equipment mas installed in 1933 for conveying the furnace fume from the baghouses to the roaster plant. At the same time pick-up lines were provided for collecting the cleanings from the vertical and horizontal cooling pipes that are between the furnace dust chambers and the baghouses. The latter installation has practically eliminated a dusty and costly hand-tramming operation. A third extension was made to the pneumatic system in 1938 for conveying 'the zinc-lead-cadmium fume from the roaster-plant baghouses and flues to a new re-treatment plant for secondary products. The success of pneumatic conveying at the Waelz plant was the determining factor in the decision to install another pneumatic unit at the Saeger zinc-roasting and sintering plant. The new unit at Saeger was installed early in 1938 for the transportation of flue and Cottrell dust, small amounts of flotation concentrates to the sinter machines, and

Jan 1, 1944

By H. Biloni, G. F. Bolling

The microsegregation in tin specimens containing 0.2, 0.5. or 1 wt pct Pb has been studied m detail. The specimens were grown from the melt in a controlled fashion and exhibited a well-developed cellular substructure. In general, a severe microsegre-gation can be observed in all the photomicrographs presented. Some observations of special interest are: the distribution of a second phase, the presence of a eutectic in several forms, the evidence for dif- THE Smialowski or cellular substructure which forms during solidification has been extensively studied during the past decade.'* Many of the im- *Most references to the cellular substructure except for the last 2 years are reviewed by Winegard.' portant characteristics of this substructure, such as its occurrence and variability with growth conditions, its association with the phenomenon of constitutional supercooling, and its effect on dislocation production and mobility, have received quantitative fusion of solute in the solid, and the enhancement of segregation at a dislocation subboundary network ("striations"). On the basis of the metallographic observations, it can be deduced that the segregation observed is representative of the solute segregation produced during crystal growth. Some deductions are also made about the interplay of the two substructures, cells and striations, and about the mode of cellular growth. investigation both experimentally and theoretically. However, the concentration profile of the solute segregated during crystal growth has not been examined in detail. Tin crystals grown from melts containing various concentrations of lead have been most extensively studied. In a recent investigation of Sn-Pb alloys, Kramer et a1.2 were able to measure the effective solute distribution coefficient, k,, at the most advanced points of the solid-liquid interface, over a large range of growth conditions, finding it to approach the value of k,, the equilibrium distribution coefficient. As will be shown, this must lead to drastic segregation. Another recent study of several Sn-Pb alloys was made by Plaskett and winegard3 who investigated the variation of growth conditions

Jan 1, 1963

By Albert H. Fay, William B. Plank

In practically all rock-excavation problem there is need for a careful study of the rock structure, its fault, cleavage or bedding planes, and even the texture of the rock itself. These studies should form the bases upon which an excavation method is selected and they should be carefully considered in predicting the amount and extent of the excavation. The need for such studies was forcibly illustrated in the problems involved in a cut made in 1929, along and underneath a 200-ft. high rock projection for a State highway near the City of Easton, Pennsylvania. The rock mass was badly faulted and also contained a number of cleavage planes at approximately right angles to the fault planes. Much of this structure was visible and could have been studied and analyzed before the work was begun. The State had rigid specifications as to finished grade and slope of cut, which apparently were made without reference to the geologic structure. The contractor complied with the specifications, under the close inspection of the State engineers. A tunnel blast was placed in the base of the cliff, with the result that 65 per cent more rock was broken than was intended by the specifications. About four years after the blast, the writers of this paper studied the circumstances surrounding the operation, to determine the cause of this excess excavation. Scope of Work The section of the roadway involved was about 200 ft. long and on a 6' curve. It was necessary to relocate points on the curve, from which all faults and cleavage planes were located and measured by the use of transit and clinometer. A plan (Fig. 1) showing the blasting tunnel, the roadway, and traces of the faults and cleavage planes on the level of the roadway, was prepared; also 13 cross-sections at varying intervals, showing the original face of the hill and the face after the blast. The original and final profiles of the rock face, taken from the plans of the State engineers, are shown in Figs. 2, 3 and 4.

Jan 1, 1937

By T. R. Armstrong

Total crude oil production in Mexico in the year 1941 is estimated at approxi- mately 41,000,000 bbl.; a daily average of 112,700 bbl. and a decrease of about 5 per cent as compared with the daily average of 120,000 bbl. produced in the year 1940, and nearly 11 per cent decrease as com-

Jan 1, 1942

By T. R. Armstrong

Total crude oil production in Mexico in the year 1941 is estimated at approxi- mately 41,000,000 bbl.; a daily average of 112,700 bbl. and a decrease of about 5 per cent as compared with the daily average of 120,000 bbl. produced in the year 1940, and nearly 11 per cent decrease as com-

Jan 1, 1942

By Eugene McAuliffe

SINCE 1917, the bituminous coal industry has surged, violently at times, across the nation's social, industrial and economic foreground. To-day a silent, yet more active, force is working within the industry, and the movement now taking place, if allowed to continue, will cause serious consequences when coal is again wanted at the rate of 550,000,000 tons annually instead of at the rate of 400,000,000 tons, the apparent requirement for 1921. I refer to the shift of tonnage from the highly unionized fields of Pennsylvania, Ohio, Indiana and Illinois to the non-union fields of Pennsylvania, West Virginia, Alabama and certain western states, and to the so-called union fields in Kentucky and Colorado, on which the union saddle rests lightly. This movement, in the absence of the usual winter transportation shortage, is taking place rapidly and will be accentuated if, as is probable, work is suspended in the union mines on March 31 next. This drift of tonnage has been made possible by the unit wage reductions in the non-union fields and by the modification of the so-called conditions that have been saddled on all mines wherever the United Mine Workers have gained a foothold; these changes permitted the first reduction in mine cost, which made possible the securance of contracts; better running time assisted in making further reductions, and the transfer of ton-nage served to increase the unit cost in the field from which it was transferred. This situation not only opposes the highly unionized operation but brings about a transfer of traffic from the roads serving such mines to those that serve in a primary or secondary manner the more favored localities. The net result is evidenced in (a) the migration of union labor to the non-union mines; (b) the deteriora-tion and decadence of union properties; (c) the neces-sary curtailment in the purchase of new equipment and in the maintenance of existing equipment and track facilities on the part of the carriers serving the union fields. This, in turn, when business is restored to normal or to the point above normal that invariably follows an adverse swing of-the business pendulum, will cause (d) a shortage of coal and coal transportation facilities; (e) an era of coal speculative debauchery with exorbitant prices and serious deflection in the matter of quality; (f) a period of labor unrest followed by de-mands for increased wage rates supplemented by a marked loss in individual efficiency, with, resultant strikes, business unrest, and the pressure of new eco-nomic theories. In 1918, the labor status with respect to relative tonnage produced was approximately as follows: pro-duced in highly organized fields, 62 per cent.; produced in partly organized fields, 21 per cent.; produced in unorganized fields, 17 per cent. During the strike of November and December, 1919, the mines that remained at work attained 35 per cento of the nominal production of soft coal, a situation made possible by the migration of union labor to non-union mines and the concentration of the nation's coal trans-portation facilities on the rails of the carriers serving the non-union fields. The history of the efforts made by the carriers to untangle the car scrambling which took place during this period and which sent the self clearing battleship type of car into western territory where it could not be readily unloaded, and the western gondola type of car to New England and the seaboard, is yet painfully recalled. -This confusion proved a serious factor in the coal car shortage that continued throughout the following year. We are drifting toward a similar situation now, propelled by economic forces rather than by a sudden strike.

Jan 1, 1922

By Horace Williams

IN VIEW of the frequent occurrence of petroleum in other parts of the world, it seems odd that so large an area as is contained within the borders of Brazil should be without this product. This apparent deficiency may be due, however, to our ignorance of the regions in which-it, may exist. In some places, indications point to the probable existence of petroleum in ages gone by; and while the presence of petroleum pools may be problematic, in several regions conditions not unfavorable to their occurrence exist. Yet, Brazil has enormous oil resources in the rich oil-shales in different parts of the country. Many of these shales are very rich and only suitable processes for the extraction of the oil are lacking. At the present time, only a few small experimental plants are producing oil by distillation from these shales. These plants have been the subject of recent investigations by the Geological and Mineralogical Survey, a. pre-liminary report of which is in the hands of the printer. The only regions where studies have not been made are the upper Amazon, the Acre, the Rio Negro, and the Peruvian frontier, which really seems to be the most promising field for, explorations of any in the country. In the vast plateau region of the interior north of the 20th parallel of latitude, granites, gneiss, mica schists, and, very old metamorphosed sedimentaries predominate. Later, sedimentaries occupy a minor position and, where found in the interior, represent a thin veneering resting on the older rocks. At several places near the coast they have a greater development and contain considerable beds of oil-shale and may, in some cases, offer conditions favorable for the occurrence of oil. Such deposits are found in the Permian rocks of central-and southern Maranhão; in the Tertiary and Cretaceous beds along the coast of Alagôas Sergipe, Bahia, and perhaps farther south in Espirito Santo; and in the Parahyba embayment north of Cape Frio and in the interior Tertiary basin of eastern Sao Paulo.

Jan 9, 1920

By H. E. Williams

In view of the frequent occurrence of petroleum in other parts of the world, it seems odd that so large an area as is contained within the borders of Brazil should be without this product. This apparent deficiency may be due, however, to our ignorance of the regions in which it may exist. In some places, indications point to the probable existence of petroleum in ages gone by; and while the presence of petroleum pools may be problematic, in several regions conditions not unfavorable to their occurrence exist. Yet, Brazil has enormous oil resources in the rich oil-shales in different parts of the country. Many of these shales are very rich and only suitable processes for the extraction of the oil are lacking. At the present time, only a few small experimental plants are producing oil by distillation from these shales. These plants have been the subject of recent investigations by the Geological and Mineralogical Survey, a preliminary report of which is in the hands of the printer. The only regions where studies have not been made are the upper Amazon, the Acre, the Rio Negro, and the Peruvian frontier, which really seems to be the most promising field for explorations of any in the country. In the vast plateau region of the interior north of the 20th parallel of latitude, granites, gneiss, mica schists, and very old metamorphosed sedimentaries predominate. Later, sedimentaries occupy a minor position and, where found in the interior, represent a thin veneering resting on the older rocks. At several places near the coast they have a greater development and contain considerable beds of oil-shale and may, .in some cases, offer conditions favorable for the occurrence of oil. Such deposits are found in the Permian rocks of central and southern Maran-hao; in the Tertiary and Cretaceous beds along the coast of Alagsas Sergipe, Bahia, and perhaps farther south in Espirito Santo; and in the Parahyba embayment north of Cape Frio and in the interior Tertiary basin of eastern Sao Paulo.

Jan 1, 1921

By W. G. Pfann

Formation and slow solidification of a molten zone in a homogeneous ingot produces a discontinuity in solute concentration at the boundary of the zone and a gradient of concentration within the zone. By using two solutes, one a donor, the other an acceptor, step or graded pn barriers can be produced. EXPLOITATION of the difference in concentration between a molten solution and the solid which freezes from it is continued in this paper. The normal segregation which results from this difference has been used for purification'.'2 and for pn barrier-formation in semiconductors."4 By means of traveling molten zones this difference has been used to effect multistage separations and to eliminate segregation in ingots." a It will be shown here that by means of stationary molten zones this difference can be used to produce discontinuities in concentration. In particular it will be shown that a pn or npn barrier can be made by the simple act of melting and refreezing a portion of a block of semiconductor, provided that the block contains proper concentrations of a donor and an acceptor in solid solution. Assumptions The operation of melting and slow refreezing will be called remelting and the interface between liquid and solid at the start of refreezing will be called the remelt bormdary. While remelting may be done for various shapes of starting crystal and remelt zone it will be assumed that the remelt zone is cylindrical, its length being measured in the direction of freezing, which is normal to the remelt boundary, and

Jan 1, 1955

By Richard L. Seal, Allan L. Turner

INTRODUCTION The chapter discusses the procedures and operations starting with the actual training of operations personnel with respect to a grinding mill circuit and a typical check-out and start-up of a grinding circuit before turning over the operating circuit to production personnel. For the purposes of this paper, it will be assumed that the mill circuit installation is at a new location or a new operation at an existing operation. Expansion of an existing grinding facility would probably require less time-consuming and less costly procedures than those that will be outlined here. There are numerous arrangements and types of equipment that can be used for grinding circuits. For example, the grinding could be wet or dry. The grinding mill could be a rod or ball mill or some combination. The circuit could be open or closed. The closed circuit classification could be accomplished with rake classifiers, spiral classifiers, cyclones, stationary screens, or vibrating screens. To limit the discussion, the grinding circuit shown on Figure I will be discussed. The circuit includes a dry ore feed by a belt conveyor (feeder) to a wet ball mill. The ball mill discharges to a cyclone feed pump box and pump. The pump feeds a cyclone type classifier with the cyclone underflow returning to the ball mill feed and cyclone overflow being the required grinding circuit product. For the purposes of this paper, it will also be assumed that the extensive overall preparation necessary for every start-up has been accomplished. These preparations are only outlined here as they have been adequately dealt with in recent papers. (1), (2), (3) The items in these preparations would include. 1. Appointment and indoctrination of the start-up organization. 2. Integration of the start-up into the overall project schedule. 3. Development of the specific start-up schedule. 4. Budget determination and monies appropriation.

Jan 1, 1982

By R. V. Whetsel, V. R. Garfias

It is estimated that during 1936 world consumption of petroleum, its products and related fuels reached an all-time peak of 1,757,778,000 bbl., an increase of 143,000,000 bbl. over 1935. As indicated in Table 1, world output of petroleum and related fuels exceeded demand by 92,510,000 bbl. during the year, as compared to an excess output of 88,000,000 bbl. during 1935. Production within the United States exceeded domestic demand by approximately 51,000,-000 bbl. in 1936, as compared to an excess output of 53,000,000 bbl. in the previous year. Outside the United States, production exceeded demand by 41,510,000 bbl. in 1936 and by 35,000,000 bbl. in 1935, indicating that foreign output is making no progress toward curtailment in line with demand. Table 1 also combines excess production in the United States with the favorable balance of exports over imports, showing that stocks in the United States were reduced by 23,400,000 bbl. in 1936, as compared to 22,447,000 bbl. in the previous year. In the rest of the world, excess output over demand combined with the excess of imports over exports from the United States indicates an unfavorable balance of approximately

Jan 1, 1937

By J. E. Hanafee, G. J. London

MANY studies of the deformation behavior of materials under a superimposed hydrostatic pressure have shown that materials brittle at ambient pressure behave in a ductile manner under pressure. Thus, with a metal such as beryllium which possesses relatively low ductility, but otherwise exhibits quite useful physical and mechanical properties, hydrostatic pressure may be particularly useful for both forming beryllium shapes and studying its deformation behavior. In fact, it has been found1"4 that polycrystal-line beryllium in both ingot and powder form appears to behave in a more ductile manner on a macroscopic level in a hydrostatic pressure environment, and it has been suggested2 that this is due to activating a new slip mode. Furthermore, Andrews and Radcliffe5 have found pressure induced nonbasal dislocation activity in hot pressed beryllium. Recently6 it has been shown in "c-axis" compression tests under hydro-static pressures up to 28 kbars that the shear stress needed to cause slip with a Burgers vector out of the basal plane (pyramidal slip) does not change with increasing pressure in beryllium with a purity of some 99.5 pct. This material is equivalent or more pure than the beryllium used in the previous pressure studies. Thus, it appears, as suggested by Inoue et al.,3 that the hydrostatic pressure affects the fracture stress rather than the stress necessary to activate pyramidal slip in beryllium. However, in "c-axis" pressure tests on high purity 12 zone pass beryllium (˜50 ppm total impurities) the macroscopic compression stress needed to cause pyramidal slip was considerably lower than that at ambient pressure.6 It has further been shown that alloying beryllium with nickel and copper in the range 2-5 wt pct also favors the occurrence of pyramidal slip in "c-axis" compression tests,7'8 while lower amounts of nickel and copper do not have significant effects. In the present study the combined effect of hydrostatic pressure and alloying high purity beryllium on the shear stress needed to cause pyramidal slip has been ascertained. A 2.5 wt pct Cu alloy was selected as the first alloy to study as this level of copper did favor pyramidal slip at room pressure. A high purity (12 zone pass) single crystal of beryllium 0.3 by 0.1 by 0.1 in. was cut and polished by an orientation and lapping technique8 so that the top and bottom compression surfaces were parallel and within 3 min of arc to the (0001) plane and the sides parallel to the {l010} and {ll20} planes. In these compression specimens, therefore, the resolved shear stress was nearly zero on both the basal and prism planes, and slip was restricted to pyramidal systems. Analysis of slip traces on the two lateral surfaces served to accurately identify the active slip planes.6'9 The pressure unit was a modified piston-cylinder device fitted with a manganin transducer coil arrangement which continuously monitored and recorded the hydro-static pressure. The load on the specimen was measured by a strain gage load cell which operated entirely within the pressure chamber. This load cell was calibrated before and after each pressure cycle at room pressure in situ and the calibration did not vary more than ±1 pet. These techniques and devices have been previously described in more detail.6 Successively higher compressive stresses were applied to the single crystal under a superimposed hydrostatic pressure until fracture occurred. The strain rate was (4.5 ± 2.0) x 10-6 sec-1 and the average rate of pressure application and release was approximately 0.3 kbars per min. As the load on the specimen was applied by the piston which was used to increase the hydrostatic pressure, the pressure increased during the compression test. This increase ranged from 0.0 to 0.8 kbars, and the maximum hydrostatic pressures are quoted in Fig. 1. The lateral surfaces of the specimen were examined in a light microscope after each pressurization/stress cycle so that the stress at the onset of {1122} pyramidal slip could be ascertained. Post compression height measurements allowed the plastic strain in the specimen to be evaluated to within 0.03 pct. The resulting compression stress-plastic strain curve is shown in Fig. 1 with results of a "c-axis" test on a similar Be-2.5 wt pct Cu single

Jan 1, 1970

By C. F. Weinaug, P. M. Blair

Many difference equations used to approximate reservoir flow problems treat the phase pressures implicitly but not the mobility-density coefficients. Such difference equations are neither wholly explicit nor implicit, but might be described as mixed. Mixed equations are relatively easy to apply. But the associated time truncation error is relatively large, and when used to solve problems characterized by high flow rates, these equations may be unstable for practical size time steps. This paper outlines the development of a completely implicit difference analogue for reservoir simulation, along with a Newtonian iterative method for solving the resulting nonlinear set of algebraic equations that arise at each time step. While this implicit equation requires two to three times more work than does the mixed equation, it is shown to markedly decrease the time truncation error and to yield a stable solution for much larger time steps than does the mixed equation. INTRODUCTION Calculation of multiphase, multidimensional flow in porous media is generally accomplished by numerical methods that involve approximating systems of partial differential equations by systems of partial difference equations. The early development of difference equation techniques was directed toward the solution of linear differential systems. However, the equations of multiphase fluid flow through porous media are highly nonlinear in that mobility and density often are strong functions of pressure and saturation. Thus, solution of the flow problems by difference equations involves solving sets of algebraic equations whose coefficients change from step to step of the calculations. Current practice is to evaluate most coefficients at the beginning of a time step and then to apply difference methods well suited for solving linear problems. At least two major difficulties arise from the use of this practice. First, evaluation of coefficients at the old time level and evaluation of pressures at the new time level results in larger time truncation errors near displacement fronts than if all quantities in the distance derivative were evaluated at the same time level. Second, evaluation of mobility coefficients at old time levels results in an unstable difference equation in regions of high flow rate. The first of these difficulties often results in optimistic recovery behind the displacement front, and the second requires the use of small time steps or special techniques in solving coning problems1 or problems of gas percolation.2 Evaluation of all quantities in the distance differences at the new time level results in a completely implicit difference system. Such a difference system has a lower time truncation error than equations in which mobilities are evaluated at the old level and pressures evaluated at the new level. The algebraic equations resulting from the fully implicit difference equation are, in this case, nonlinear and require some iterative method for their solution. This paper develops fully implicit difference equations for two-phase flow in porous media, describes their solution by Newtonian iteration, and gives examples of problems more easily solved by the new method than by previous methods. EVOLUTION OF DIFFERENCE EQUATIONS FOR NONLINEAR PROCESSES The completely implicit difference equation used in these calculations results from evolution beginning with explicit difference equations, proceeding through what we will call "mixed" equations, and arriving now at a completely implicit equation. Let us illustrate the evolution by considering different analogs of the nonlinear equation

Jan 1, 1970