Search Documents

By R. C. Beckstrom

Russia's first "Petaletka'' has ended. Technically it did not succeed but practically it has been a great achievement in the petroleum industry. Out of the chaos of revolution and civil war Russia has developed her oil industry to second place in the world's production. For 1932 production of crude oil is estimated at 150,000,000 bbl. and refined products at 145,000,000 barrels. Russia has been able to give the petroleum industry every advantage that a government can extend to a fast growing industry. She has obtained all of her property by confiscation. Under government ownership, operation and control, her petroleum industry is not handicapped in any way by state rulings or by unnecessary competition in production, refining and marketing. There are no damage suits resulting from offsetting, flooding, repressuring, laying of pipe lines, building of docks or other necessary work. Russian oil fields2 have been easy to develop and operate. They lie advantageously to transportation for foreign markets. The chief disadvantages have been a lack of credit and technical cooperation, but the former is being overcome by the sacrifice of the people. They go without the comforts of life that all salable articles may be exported for the imports of modern machinery. Modern machinery is fast replacing the obsolete and worn-out equipment. Technical cooperation has been difficult because it has been necessary to train thousands of adults to do technical and mechanical work. Great quantities of pipe, tools and electrical equipment were necessary for the rapidly developing fields and refineries. The supplies have been inadequate and the quality poor. This lack of equipment, along with the untrained technical supervision, has been the cause of the proposed quota falling short. Fig. 1 shows the production for 1931 and 1932. During 1932 a large percentage of the oil was produced in the proven fields of the Caucasus.

Jan 1, 1933

By R. G. Garlick, H. B. Probst

Tungsten single-crystal specimens of various orientations were deformed in tension at room temperature. Slip traces indicated both (112)(111) and (110) (111) slip; however, about 10 pct plastic dejormation was required bejore these traces could he seen. Resolzled shear-stress considerations indicated that at least some of the particular systems observed were not those on which slip initiated hut were secondary systems. This is highly probable, considering the high plastic strains involved. Analysis of the stress data with respect to possible slip systems indicated that slip must have been initiated at stresses below the proportional-limit stresses measured. ALTHOUGH there is general agreement that slip deformation in fcc and hep metals takes place on the plane of close packing and in the direction of close packing, there is no such agreement for slip in bcc metals. It is generally agreed that the close-packed direction (111) is the slip direction, but investigations have led to conflicting descriptions of the slip plane. As Hoke and Maddin1 point out, there are essentially four points of view. 1) Deformation in bcc metals is composite shear on (112) and (110) planes or on nonparallel (110) planes, and any apparent slip on other planes can be accounted for completely by slip on these planes. Chen and Maddin have reported this to be the possible case for molybdenum." 2) Slip occurs in the (111) direction and is limited to {110), {112), and (123) planes (the three closest packed planes of the lattice). 3) Slip occurs in a (111) direction, but not necessarily on planes of close packing (banal slip). 4) Slip occurs in those directions and on those planes for which ß, the ratio of Burgers vector to interplanar spacing, is a minimum. The slip systems of the bcc metal tungsten have never been fully determined, although several investigators have reported pertinent results.3"7 The present work was initiated to determine the active slip systems in tungsten at room temperature, the critical resolved shear stresses associ- ated with these systems, and the orientation dependency of operative systems. These features of tungsten deformation at room temperature have never been reported in the literature. The authors find this somewhat surprising, particularly in view of the availability of tungsten single crystals since the advent of electron-beam zone-melting techniques and the widespread interest in refractory metals. It would seem apparent that such work has been attempted but the results have not been reported, possibly due to the conflict with deformation theory. The results of the present work conflict with any straightforward description of deformation based on the proposed explanations of slip in bcc metals. Although these conflicts have not been resolved, a presentation of the problem seems in order and should be of value to others working in this field. MATERIALS AND PROCEDURE Single-crystal tungsten rods of 1/8-in. diameter were grown from undoped commercial rod by one-pass electron-beam zone melting in apparatus previously described by witzke.8 Representative analyses of the rod before and after melting are given in Table I. There was no detectable zoning of impurities during melting. Buttonhead tensile specimens, as shown in Fig. 1, were machined from single crystals. Two flats 90 deg apart were ground in the gage length of each specimen. These flat surfaces facilitated the analysis of slip traces. No attempt was made to position these flats with respect to the crystal orientation. The worked surface layer of the machined specimens was removed by electrolytic polishing in a NaOH solution. Tensile-axis orientations were determined by standard Laue back-reflection techniques. The sharpness of the Laue spots indicated that the crystals were free of strain.

Jan 1, 1964

By John Wulff, R. Buehl, H. Hollomon

Although the main features of the transformations occurring in 18-8 have been published already, certain conclusions merit questioning and discussion. The questions may be summarized as follows : 1. If ferrite is formed by cold-working austenite, what happens to the carbon with which the ferrite and austenitc are both presumably supersaturated? 2. What is the nature of the alpha-ferrite formed at grain boundarices by chromium-carbide precipitation at these boundaries?

Jan 1, 1940

By R. Buehl, John Wulff, H. Hollomon

Although the main features of the transformations occurring in 18-8 have been published already, certain conclusions merit questioning and discussion. The questions may be summarized as follows : 1. If ferrite is formed by cold-working austenite, what happens to the carbon with which the ferrite and austenitc are both presumably supersaturated? 2. What is the nature of the alpha-ferrite formed at grain boundarices by chromium-carbide precipitation at these boundaries?

Jan 1, 1940

Beyond the industrial suburbs of Melbourne to the southeast are brown coal deposits just under the fertile soil of the Latrobe Valley. These deposits rank as one of the wonders of the world. The manner in which this resource is put to use is one of the great engineering accomplishments of our time and also a prime example of Australian elan. The brown coal, with over 60% water content, occurs in beds from 200 to 400 ft thick, under 50 ft of cover. Fifty thousand tons of coal per day move in a nearly continuous stream from mining face to boilers. The power plants supply two thirds of the State of Victoria's requirements, about 800 megawatts. Surge capacity between mine and power plant is sufficient for 12 hr steaming time! Victorian brown coals have been known since the middle of the 19th century. However, it took a strike of bituminous coal miners in 1915 to bring brown coal permanently into the picture as a fuel for power generation. In Australia, power generation is a State function. The great development of brown coals has been under the State Electricity Commission of Victoria.

Jan 10, 1964

By L. B. Lindemuth

TO those who are in a position to carry the thought to a conclusion, I would like to present a theory of the cause of blisters in ' galvanized sheets. Blisters that are caused from piping and shrinkage cavities will not be considered, because the reason for their formation is entirely obvious. Blisters that periodically occur, with no apparent system of location, number, size or grouping, and then disappear with no apparent change in manufacturing method, are the ones to which this theory would apply. Examination of blisters of the latter type has shown that they contain hydrogen gas at atmospheric pres-sure, and that occasionally traces of oxide or sulfide are found on the inner surface of the blisters. These two characteristics have led to the rather general idea that hydrogen gas generated in pickling, and that iron oxide supposed to be inherent in the ingot and causing weak spots, were, in some manner, responsible for the development of blisters in galvanizing. The theory which I wish to advance is that these blisters are caused by moisture that has penetrated the steel after the annealing operation. This moisture comes from the atmosphere, or from pickling or wash-ing, and when it is suddenly expanded into superheated steam in galvanizing, the increase in volume is so great that it cannot escape with sufficient rapidity through the small opening which it entered as moisture. The pressure so generated forces the sheet apart along those lines of lamination that may be found in practically all flat sections of steel rolled comparatively cold.

Jan 5, 1927

By R. L. Brown, A. C. Fieldner

Committee it supports pioneering research on the development of a coal-burning gas turbine and through the Mining Development Committee it promotes research on a new type of continuous mining machine that operates without using explosives. Other organizations have contributed major publications on fundamental and applied coal research in the last two decades, including the Minerals Industries Experiment Station of Pennsylvania State College, the Illinois Geological Survey and University of Illinois, the University of West Virginia, the University of Michigan, the University of Alabama, the University of North Dakota, the Massachusetts Institute of Technology, the Koppers Company, the U. S. Bureau of Mines, and, in recent years, the Institute of Gas Technology. Engineering development work, which is included in the overall estimate of $20,000,000, is conducted largely by manufacturers of equipment, and this portion of the estimate is difficult to gage. It represents a large proportion of the estimate and probably is too small rather than too large. For example, the development of mobile coal-loading machines and continuous mining machines, outstanding in recent mining research, undoubtedly involved a high cost. Coal Mining From an economic point of view, the greatest research development in the coal industry obviously has been the growing degree of mechanization in mining. The percentage of underground-mined bituminous-coal output mechanically loaded has risen from 3 pct in 1926 to 67 pct in 1949. Coal operators and equipment , manufacturers have united in designing machinery. Loading machines of large capacity and astonishing flexibility are in common use. Shaking conveyors transport coal from producing faces to transfer points from which it may be carried long distances underground and on the surface; and in many mines rubber-tired shuttle cars carry the coal from the loader to the

Jan 1, 1952

By R. W. Winson

Asbestos is the generic name given to a group of fibrous mineral silicates found in nature. They are all incombustible and can be separated by mechanical means into fibers of various lengths and cross sections, but each differs in chemical composition from the others. The commercial grades of asbestos consist of a spectrum of lengths and sizes and are not definitive as are most organic fibers. It is generally recognized that there are two main groups of asbestos. The first only contains the fibrous serpentine called chrysotile and comprises about 94% of the world production of asbestos. The second group contains five minerals in the amphibole series+rocidolite, amosite, anthophyllite, tremolite, and actinolite. The latter two have no commercial importance. Properties Physical The structures of asbestos fibers have been studied intensively over a number of years. X-ray diffraction patterns have been used as a means of identification and classification. Low angle X-ray scattering techniques have shown that chrysotile fibers are "hexagonally close packed" and parallel to each other, having cross-sectional diameters varying from 18014 to 300A units, while the amphibole fibers are many times larger in cross section. Electron micrographs of the more common types of as- bestos are shown in [Figs. 1-4]. [Fig. 1] illustrates the softness and flexibility of chrysotile which make it suitable for textile-type products. For a number of years there was considerable controversy over the exact nature of chrysotile fiber, but the photographic evidence in [Figs. 5-7] clearly show that it is tubular in structure. The curvature is the result of the mismatch in the dimensions of the silica [Si,O,l and brucite [Mg(OH),] layers which are on the inside and outside, respectively, of a double sheet. This curvature had been predicted by Pauling (1930) years ago based on the molecular dimensions of the two component structures.

Jan 1, 1975

By H. Landssberg

Subsidence caused by mining operations has been a matter of interest for the mining engineer for just 111 years, since the Belgian committee for study of subsidence in the city of Liege submitted its first report in 1825. This interest is fairly expressed in the enormous amount of literature that has since appeared on this subject. A bibliography, probably far from being complete, which preceded this study as a preliminary survey, comprises more than 800 titles. In spite of this fact the problem remains today as acute as it has ever been. The questions of as good a recovery as possible of the national resources, the safety of the operations, and the protection of private and public property are the important angles from which to look at the problem. The Problem To systematize an investigation regarding the effects of mine excavations two different aspects have to be dealt with: (1) the subsidence of the immediate roof above the workings, affecting the safety of the workers and the progress and efficiency of the operations; (2) the subsidence of the surface, which is also, from the point of time, the second event. The immense importance of surface subsidence as regards the impairment of surface structures of every kind in a mining area is self-evident. Both effects result from reactions of the strata overlying the excavations and they depend mainly on the extent of the excavations and the structure and geological condition of the strata. It has been stressed repeatedly, in this country principally by G. S. Ricel,† that for the understanding of the phenomenon of subsidence accurate surveys are the most urgent necessity. In the past, however, at least in the normal course of mining operations, these surveys have been very crude. The control of the roof in the mine is left to the observation of the behavior of the timber, warning cracks and sounds in roof and walls and to the general judgment and experience of the worker and his supervisors. In any given case this may or may not be sufficient to prevent fatalities but certainly it does not give any accurate information as to what is happening in roof and strata. On the surface, principally in endangered areas, surveys have been conducted more frequently, but also in this case usually weeks or even

Jan 1, 1936

By H. Landssberg

Subsidence caused by mining operations has been a matter of interest for the mining engineer for just 111 years, since the Belgian committee for study of subsidence in the city of Liege submitted its first report in 1825. This interest is fairly expressed in the enormous amount of literature that has since appeared on this subject. A bibliography, probably far from being complete, which preceded this study as a preliminary survey, comprises more than 800 titles. In spite of this fact the problem remains today as acute as it has ever been. The questions of as good a recovery as possible of the national resources, the safety of the operations, and the protection of private and public property are the important angles from which to look at the problem. The Problem To systematize an investigation regarding the effects of mine excavations two different aspects have to be dealt with: (1) the subsidence of the immediate roof above the workings, affecting the safety of the workers and the progress and efficiency of the operations; (2) the subsidence of the surface, which is also, from the point of time, the second event. The immense importance of surface subsidence as regards the impairment of surface structures of every kind in a mining area is self-evident. Both effects result from reactions of the strata overlying the excavations and they depend mainly on the extent of the excavations and the structure and geological condition of the strata. It has been stressed repeatedly, in this country principally by G. S. Ricel,† that for the understanding of the phenomenon of subsidence accurate surveys are the most urgent necessity. In the past, however, at least in the normal course of mining operations, these surveys have been very crude. The control of the roof in the mine is left to the observation of the behavior of the timber, warning cracks and sounds in roof and walls and to the general judgment and experience of the worker and his supervisors. In any given case this may or may not be sufficient to prevent fatalities but certainly it does not give any accurate information as to what is happening in roof and strata. On the surface, principally in endangered areas, surveys have been conducted more frequently, but also in this case usually weeks or even

Jan 1, 1936

By R. C. Rumble

To /neet the need for a subsurface flowmeter capable of measuring low rates of flow, a new type flowmeter has been built and tested in the field. This instrument is self-contairzed, can be run on a wire measuritzg line, and may be run through 2-in tubing. It consists of a rotameter flow-measuring assembly used in conjuncfion with a conventional subsurface instrument clock and chart. Integral with the tool is an inflatable packer which, by effecting a seal between casing and tool, diverts all fluid through the metering assembly. Packers of different size adapt the tool to different sizes of casing or liner. The flowmeter is capable of measuring rates of flow as low as 4 BID. The flowmeter has been run experimentally in seven wells. It has yielded satisfactory resrrlts in five of the wells, and in the other two it failed to operate because of loose sand in the hole. INTRODUCTION One of the oldest problems facing the producing branch of the petroleum industry is the location of depths of entry of fluid into a wellbore and the determination of the amount of fluid entering at each depth. This problem is often encountered in oil and gas wells completed in single producing horizons as well as in multiple pays; it is a common problem in oil wells which produce excessive volumes of gas. Several subsurface instruments designed to detect and meter flow in the producing interval of wells have been described in the literature.1,2,3,4 Most of these, however, were apparently intended for use in wells producing at relatively high rates of flow, and consequently lack sensitivity to low flow rates. Because of this and of other possible disadvantages inherent in these instruments, development of the subsurface flowmeter described in this report was undertaken. DESIGN OF FLOWME'I'ER Design Requirements In considering the requirements for a flowmeter that would not be subject to the limitations of devices existing at the time work was started, attention was first given to the size of the tool. Such an instrument should be of sufficiently small diameter that it could be lowered readily in 2-in tubing in a producing well. The flowmeter should contain a recording unit so that it might be run on a wire measuring line with conventional reeling equipment. It should not be too long to be accommodated by a portable lubricator of the type used for running conventional subsurface instruments. The metering mechanism of the flowmeter should not be affected appreciably by the viscosity or density of the flowing fluid. Such an instrument should record flow rates in the range from less than 10 B/D to over 100 B/D. To achieve this, a packer should he provided to divert through the instrument all fluid flow in the wellbore. This packer should be of such nature that in the event of excessive flow the fluid would bypass the instrument instead of forcing it up the wellhore. General Description A flowmeter incorporating most of the desired features outlined above was developed and built. The instrument is an elongated tubular device terminated on

Jan 1, 1956

By V. H. Wilhelm

Drilling activity in California during 1939 decreased approximately 15 per cent from that of the previous year. New reserve discoveries were the lowest in many years, but extensions, development of deeper sands, and reappraisals, indicated enough new potential to more than equal 1939 withdrawals of about 223,644,000 barrels. On June 1 a new uniform method of allocation was adopted, which had the immediate effect of reducing production, so that approximately 6,000,000 bbl. of crude were withdrawn from storage during the year. Market demand averaged 628,845 bbl. per day as compared with a daily production of 612,945 barrels. The rate of drilling was slow during the first five months because of the unfavorable storage situation. Subsequent to the adoption of the new uniform method of allocation on June 1, drilling was speeded up and continued at a rapid rate throughout the remainder of the year. As a result of prospecting, four new fields were discovered and seven fields were measurably extended. All of the new discoveries were made in the San Joaquin Valley. Statistics of production and development arc given in Fig. 1 and Tables 1 to 3. New Discoveries Coalinga-Northeast.—The Amerada Petroleum Corporation discovered a second Eocene shore-line field north of the Coalinga Nose when it brought in well S.P.L. 7-17 in sec. 17-19-16, flowing 4230 bbl. of 32.4" gravity oil and 14,200,000 cu. ft. of gas at a depth of 8237 ft., from the "Gatchell" sand of Eocene age. This field, 2 miles north of the Coalinga Nose field, is considered to be a separate structure because it has a gas cap and a lower water table. The structure is a broad, gentle anticlinal nose probably separated from the southerly Coalinga Nose field by a shallow syncline. Production is sealed updip by the pinching out of oil sands. The average sand thickness is approximately 200 ft., the top 75 ft. containing mainly gas. The sand has an average permeability of 1000 millidarcys and an average porosity of 25 per cent. The productivc area of the field is estimated to be between 1200 and 1500 acres.

Jan 1, 1940

By V. H. Wilhelm

Drilling activity in California during 1939 decreased approximately 15 per cent from that of the previous year. New reserve discoveries were the lowest in many years, but extensions, development of deeper sands, and reappraisals, indicated enough new potential to more than equal 1939 withdrawals of about 223,644,000 barrels. On June 1 a new uniform method of allocation was adopted, which had the immediate effect of reducing production, so that approximately 6,000,000 bbl. of crude were withdrawn from storage during the year. Market demand averaged 628,845 bbl. per day as compared with a daily production of 612,945 barrels. The rate of drilling was slow during the first five months because of the unfavorable storage situation. Subsequent to the adoption of the new uniform method of allocation on June 1, drilling was speeded up and continued at a rapid rate throughout the remainder of the year. As a result of prospecting, four new fields were discovered and seven fields were measurably extended. All of the new discoveries were made in the San Joaquin Valley. Statistics of production and development arc given in Fig. 1 and Tables 1 to 3. New Discoveries Coalinga-Northeast.—The Amerada Petroleum Corporation discovered a second Eocene shore-line field north of the Coalinga Nose when it brought in well S.P.L. 7-17 in sec. 17-19-16, flowing 4230 bbl. of 32.4" gravity oil and 14,200,000 cu. ft. of gas at a depth of 8237 ft., from the "Gatchell" sand of Eocene age. This field, 2 miles north of the Coalinga Nose field, is considered to be a separate structure because it has a gas cap and a lower water table. The structure is a broad, gentle anticlinal nose probably separated from the southerly Coalinga Nose field by a shallow syncline. Production is sealed updip by the pinching out of oil sands. The average sand thickness is approximately 200 ft., the top 75 ft. containing mainly gas. The sand has an average permeability of 1000 millidarcys and an average porosity of 25 per cent. The productivc area of the field is estimated to be between 1200 and 1500 acres.

Jan 1, 1940

By P. G. Chamberlain, E. R. Podnieks, R. E. Thill

Although published data on the physical properties of rock are voluminous, information is often lacking on the environmental conditions under which such data were acquired. Efforts are frequently directed to improve specimen tolerances and preparation procedures; but investigators often overlook giving the rock environment equally careful control during the testing program. Generally, tests are conducted at existing laboratory room conditions, and the prepared rock specimens are frequently, if not most commonly, air-dried for various lengths of time before testing. The standard testing atmosphere recommended by the American Society for Testing & Materials (ASTM)1 is 73.4°F and 50% relative humidity. To maintain a rock at 50% relative humidity for testing purposes, however, requires special equipment and preconditioning procedures, as this study demonstrates. Relatively small variations in the moisture content of a specimen, for example, due to the coolants or lubricants used during specimen preparation, can cause significant variations in the physical properties measured. Such moisture variations may occur in the rock specimen even after it is air-dried, since laboratory humidity conditions commonly fluctuate from day to day. For these reasons, this study emphasizes procedures for preconditioning and maintaining a controlled environment during testing. Although the effects of moisture or temperature on rock properties have previously been studied, their combined effect on rock properties is unknown. In this study, uniaxial compressive strength, Young's and stiffness moduli, and longitudinal wave velocity were determined and compared under controlled conditions of temperature, moisture, and pressure for 11 environments considered to be of particular interest in laboratory, in-situ, and even simulated lunar environments. The following environments were selected for this program: -250°F under dry, 50%

Jan 1, 1972

By W. A. Naismith, R. T. Pakalnis

The Umgal a section of the We1gedacht Exploration Company Ltd., a member of the Rand Mines Group, is situated near Utrecht in the province of Natal, South Africa. Two coal seams, the Alfred and Gus, are mined to fulfill commitments to both inland and export markets. To increase extraction in the high quality Alfred Seam, pillar extraction, known locally as stooping, was introduced to the mine in September, 1980. Mining is a conventional cut-drill -blast operation and takes place under a unique set of geological conditions viz. moderately thick seam at 3.5 m; rapidly varying cover from 25m to 120 m; an overburden containing competent sandstone and dolerite horizons. In order to improve the understanding of the manner in which the pillar and overburden interact during pillar extraction, a largely visual system of monitoring backed up by roof-floor convergence measurements was employed. Preliminary analysis of the observations suggests that roof collapse or goafing occurs in three phases but is only initiated once a critical amount of convergence has taken place.

Jan 1, 1983

By Francis S. Kendorski

INTRODUCTION Nuclear waste has been generated since the time of the Curie's and continues to be generated worldwide at an ever-increasing rate as the world will (and should) rely more and more upon fission (and hopefully fusion) for power. Also, the needs for strategic weapons will also generate so-called defense wastes. The largest class of high level nuclear waste (HLW) is spent fuel, the tail end of the nuclear reactor fuel cycle. At present, spent fuel is stored at the reactors producing it or at a few accepting places for away-from-reactor storage. All such storage facilities, as presently constructed, will begin to run out of usable storage space during the next decade or so. Congress enacted and President Reagan signed into law in early 1983 the National Nuclear Waste Policy Act of 1982. This law provides for the permanent isolation of nuclear waste in deep geologic repositories. The Act sets 1998 as the date at which the first repository should be operational. This date is extremely ambitious, and the Department of Energy (DOE), which is charged with the responsibility of constructing and operating repositories, admits that this date will slip by at least a few years. The Act also provides for licensing of repositories by the Nuclear Regulatory Commission (NRC) in a fashion very similar to nuclear power generating reactors. This requirement imposes a very special rigor on the analyses, investigations, designs, construction, and operation of repositories so as to assure the protection of the public and the environment from radioactive contamination. In addition the states and affected Indian Tribes must be consulted, especially concerning siting, and, needless to say, no one wants a HLW repository in their back yard.

Jan 1, 1984

By E. G. Woodruff

The earlier struggles in petroleum geology were directed to solving the Qrigin and method of accumulation of petroleum. We are now fairly well agreed on those subjects. Most of us think that the great mass of petroleum commercially produced comes from plants or animals, or possibly from both. We are confident that the oil was not produced where it is now found but has accumulated in reservoirs of various kinds. The types of reservoirs are certainly variable but they just .as certainly follow definite geologic laws. Some of these types of reservoirs can be determined from surface study; others cannot. We know, too, that these types of reservoirs (largely structures such as anticlines, domes, and terraces) are much more widespread than the oil pools. In other words, there are many places where good sands and good structures exist but where oil is not found. It is the purpose of this paper, therefore, to attempt to analyze, from a regional standpoint, some of the conditions that control the presence or absence of oil pools and to group them in a regional way, hence the term "Petroliferous Provinces." The paper lays no claim to presenting new facts but attempts to group and classify the information that so many have expressed again and again. The essential factors for an oil field are petroleum, a reservoir material, and conditions under which the petroleum can enter the reservoir but cannot escape except through the drill holes. The paper will first discuss the source of petroleum as it occurs in definite regions, then the regional arrangement of reservoir strata, and finally the areal arrangement of structures. To have petroleum, there must be a source. Since living matter is considered the source of the petroleum, geological conditions must have been such that living organisms were abundant. Arid regions on the earth's surface have not given rise to living things in sufficient abundance to produce oil; similarly, too cold regions and saline inland lakes. The converse of this is that warm moist conditions must prevail to produce an abundance of vegetable matter. Before an area can be

Jan 1, 1921

By Freeman Bishop

Copper production has been under Government scrutiny for many years because it's known as a concentrated industry which in turn creates what many economists label administrative prices. Neither of these conditions is illegitimate, per se, the Federal Trade Commission and the Justice Department have said time and again. But Justice spoke up once more. This time over a Puerto Rican copper development planned by American Metal Climax, Inc., and the Kennecott Copper Corp. Bureaucratic Dichotomy Creates Confusion and Conflict In the Copper Industry Ian MacGregor, chairman and chief executive officer of Amax, said Justice in a recent communique questioned the propriety of the proposal of a joint copper venture in Puerto Rico. At the same approximate time, Dr. Hendrik S. Houthakker, chairman of the President's Commission on Copper, was urging copper producers to expand production to help hold down prices by making more copper available to all consumers. This, Mr. MacGregor said, is creating confusion and conflict, since the Administration from one source is chastising the industry for doing what another branch requests.

Jan 1, 1970

By D. O. Hobson

Zirconium single crystals of various specific orientations were fabricated by rolling or drawing. The resulting textures were determined and are discussed with respect to the deformation modes that produced them. The crystals deformed in a predictable manner by combinations of up to third-order twinning with three twinning modes and by slip. Twinning was found to play a major role in initial texture formation. Texture changes produced by slip occurred only at the higher reductions. The twinning sequences that produced each intensity peak during the initial reductions could be identified. Schmid factor criteria were found useful in predicting which deformation modes to expect for each crystal orientation and fabrication procedure. The possible application of these data to poly-crystalline material is discussed. PREFERRED orientation or texture has a significant effect on the properties of most materials, causing anisotropy in fabricated cubic metals and enhancing the natural anisotropy of noncubic metals. This study evaluates the effects of several fabrication methods on the textures formed from specific starting orientations of zirconium single crystals and, it is hoped, gives an insight into the effects of the same operations on poly-crystalline material. BACKGROUND In fcc and bcc metals, texture changes take place by gradual lattice rotations caused by the operation of one or more slip systems. Deformation twinning plays an insignificant role in the deformation of such metals. In zirconium and its alloys, however, and in many other hep metals the ability to twin allows very rapid texture changes to be made with very small amounts of deformation. The deformation systems found in zirconium and its alloys are prism slip and three twinning modes.1 Slip occurs on the {1010}< 1120) system. There is little or no appreciable basal slip in zirconium. The twinning planes, illustrated in Fig. 1, are {1012}, {ll2l}, and {1122}. Two twinning modes, the {1012} and the {ll2l} operate for a tensile stress along the basal pole. A compressive stress parallel to the basal pole is required for {ll22} twinning. These twinning operations cause a 35- to 85-deg reorientation of the basal pole. The {1012} twin is the predominant tensile twin at room temperature. The twinning shears, S, are shown in the figure. A criterion for predicting which deformation system will operate when a grain is subjected to a known stress state is the Schmid (orientation) factor. This factor gives the fraction of the applied stress that computer program was written2 to calculate the Schmid factors for the four deformation modes in zirconium. It assumed three orthogonal stress axes and considered ninety-one different orientations of the basal pole in one octant of this stress space. At each basal pole position the Schmid factors were calculated for seven positions of rotation at 10-deg increments of the unit cell about the basal pole. Schmid factors were determined for a total of 637 orientations and for twenty-four deformation systems in each orientation. The program listed the Schmid factors for uniaxial stress parallel to each axis and, to approximate rolling, or-thonormal biaxial stress was also considered. Fig. 2 shows the range of orientations over which the various types of deformation would tend to predominate in biaxial plane strain with the stresses, equal magnitude. The exact boundary position between regions of different deformation modes depends, however, on the relative values of the critical shear stress for each deformation mode. Fig. 2 is drawn on the assumption that they are equal and it therefore may be only approximately correct. It is also recognized that the biaxial stress analysis may not be applicable in certain crystal orientations. EXPERIMENTAL PROCEDURE Single crystals of zone-refined zirconium, produced by Wilson of this Laboratory,3 were electrical-discharge-machined to form specimens for rolling, tube-drawing, and rod-drawing studies. Specimens were rolled at room temperature on 2-|--in.-diam hand-powered rolls from three different starting orientations: 1) the basal plane parallel to the rolling plane and the [1120] in the rolling direction, (0001)[ll20]; 2) the (1120) plane parallel to the rolling plane and the basal pole in the rolling direction, (1120)[0001]; and 3)_the (1120) plane parallel to the rolling plane and the [1100] in the rolling direction, (1120)[ll00]. Drawing specimens were cut with the [0001] direction as the drawing direction in the tube blank and [1120] as the drawing direction in the rod specimen. The drawing

Jan 1, 1969

By C. H. Green

Recently two papers on the structure of eutectics were read before thc British Institute of Metals, one by F. L. Bradyl and the other by A. Portevin. 2 In the preparation of photomicrographs of laboratory specimens as illustrations for student work, and in connection with various researches, the writer has been working along the same line for some time and, therefore, was much interested in the results given, especially those of Portevin. He has correlated the information on the subject and has outlined a broad scientific basis for future work along this line. It is largely with the idea of adding something by way of illustration to the work already done that this paper is written. The eutectic is generally understood to mean the alloy having the lowest melting point of any alloy of the system, and in which the melt becomes supersaturated with reference to the two or more phases which separate out simultaneously or alternately. From the surface pattern, the eutectic means a structure with no primary crystals. It is not always easy to get the exact eutectic composition in making any alloy; in fact, a slight range in composition may be expected and some of the coarser particles may be richer in either of the composing metals. Even when chemical analysis shows the right composition, differences in density of the pure metals may cause segregation, or supercooling resulting from different crystallizing properties may give a surface pattern the appearance of being on one side of the eutectic point. However, the alloys on either side of the eutectic composition, showing primary crystals of one of the phases and the effect of the proeutectic form on the surface pattern of the eutectic make a very interesting study, which is slightly touched upon in this paper. The phases, or microconstituents, of a eutectic may be pure metals (Pb-Sb, Tl-Au), solid solutions (Cd-Zn), a pure metal and a solid solution (Ag-Sn), or a pure metal or solid solution with an intermetallic compound (Sb-Mg, Sb-Cu, As-Cu, Bi-Te, etc.).

Jan 1, 1925