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Mansfield MERRIMAN,Lehigh University, South Bethlehem, Pa. (communication to the Secretary*):—The formulas established by Mr. Campbell require the use of tables in order to take into account the influence of manganese on the tensile strength of steel. On examining these tables I find that the quantities given therein may be expressed by simple algebraic forms, so that formulas for tensile strength may be written which can be used without the help of tables. Referring to the case where the carbon is determined by

Jan 1, 1906

By Helmut Thielsch

MeTallographic specimens whose surfaces are to be investigated are too thick to allow either light or electrons to pass through them for microexamination by transmission. This difficulty is overcome with optical microscopes by illuminating the surface through the objective lens. For electron microscopes best results are obtained by preparing thin replicas of the surface of the specimen, placing them in the microscope and passing the electron beam through them. Since electron microscopes represent a rather recent invention, they have found little application as compared with optical microscopes. This is true because, aside from the cost of new equipment and development of new techniques, some of the older replica methods necessitated the destruction of the surface from which a thin transparent replica was obtained. In other processes in which the surface is preserved, either too tedious a procedure is required, unsuited to "mass-production" requirements of industrial laboratories, or replicas of insufficient contrast and sharpness are produced. In general, investigations with the electron microscope involve five steps: (I) polishing the surface of the metal specimen, (2) proper etching of the surface, (3) preparing the suitable replica from the surface, (4) examination and phorography in electron microscope and (5) interpretation. Preparation of Metal Surfaces Usual metallographic polishing is generclly satisfactory. It is important though that the final polish be applied very carefully, since otherwise evidence of a small amount of deformation might show up even on relatively deeply etched surfaces. A high-power microscope should be used to determine the suitability of the polish and etch. This, of course, is not different from optical examinations, but in these, if a deep etch is used, the problem is less serious. It is frequently difficult to detect with optical microscopes poor polishing aside fiom superficial scratches before etching. Figs. I and 2 show micrographs of "well" and "poorly" polished nickel etched by immersing the sample for 20 min. in a solution containing 8 grams cupric sulphate in 40 C.C. of concentrated HCl and 40 C.C. of Hz0 (Marble's reagent). The sample shown in Fig. I was polished in its final stages for 5 min. on a carborundum wheel followed by ro min. on a rouge wheel, whereas the sample shown in Fig. 2 was polished only I min. on the rouge wheel. Generally, this procedure does not guarantee that the surface of the specimen will be either undistorted or deformed. It was applied here merely to show the effects Of good and poor polishing. To the experienced investigator, plastic deformation is

Jan 1, 1946

By Helmut Thielsch

MeTallographic specimens whose surfaces are to be investigated are too thick to allow either light or electrons to pass through them for microexamination by transmission. This difficulty is overcome with optical microscopes by illuminating the surface through the objective lens. For electron microscopes best results are obtained by preparing thin replicas of the surface of the specimen, placing them in the microscope and passing the electron beam through them. Since electron microscopes represent a rather recent invention, they have found little application as compared with optical microscopes. This is true because, aside from the cost of new equipment and development of new techniques, some of the older replica methods necessitated the destruction of the surface from which a thin transparent replica was obtained. In other processes in which the surface is preserved, either too tedious a procedure is required, unsuited to "mass-production" requirements of industrial laboratories, or replicas of insufficient contrast and sharpness are produced. In general, investigations with the electron microscope involve five steps: (I) polishing the surface of the metal specimen, (2) proper etching of the surface, (3) preparing the suitable replica from the surface, (4) examination and phorography in electron microscope and (5) interpretation. Preparation of Metal Surfaces Usual metallographic polishing is generclly satisfactory. It is important though that the final polish be applied very carefully, since otherwise evidence of a small amount of deformation might show up even on relatively deeply etched surfaces. A high-power microscope should be used to determine the suitability of the polish and etch. This, of course, is not different from optical examinations, but in these, if a deep etch is used, the problem is less serious. It is frequently difficult to detect with optical microscopes poor polishing aside fiom superficial scratches before etching. Figs. I and 2 show micrographs of "well" and "poorly" polished nickel etched by immersing the sample for 20 min. in a solution containing 8 grams cupric sulphate in 40 C.C. of concentrated HCl and 40 C.C. of Hz0 (Marble's reagent). The sample shown in Fig. I was polished in its final stages for 5 min. on a carborundum wheel followed by ro min. on a rouge wheel, whereas the sample shown in Fig. 2 was polished only I min. on the rouge wheel. Generally, this procedure does not guarantee that the surface of the specimen will be either undistorted or deformed. It was applied here merely to show the effects Of good and poor polishing. To the experienced investigator, plastic deformation is

Jan 1, 1946

By AIME AIME

ALL 32 of the Local Sections of the Institute in the continental United States and practically all of the Divisions as well, had representatives present at the Conferences of Local Section and Division Delegates at the Annual Meeting. Three sessions were held, two on Monday and one on Thursday, both the incoming and outgoing Presidents of the Institute being on hand to con- duct the meetings. H. J. Brown was called to the chair during a portion of the last session, President Fulton having to leave early. Complete minutes of the meetings have ,been sent to all delegates. In general, the Local Sections appeared, from their reports, to have risen to the wartime demands made upon them with their usual resourcefulness. Apparently more difficulty has arisen in the last year in arranging attractive programs and securing acceptable speakers, this being perhaps attributable to the fact that most technical men have been extremely busy. Careful planning ahead .has usually brought good results, however. Another wartime difficulty has been the matter of transportation to meetings, gasoline rationing and congestion on the railroads and buses being a handicap to attendance. Sharing cars has proved practical as a method of meeting this issue, this again requiring planning. Suitable meeting places and a supply of food have been another difficulty for some local groups.

Jan 1, 1944

By I. M. Bernstein

The steady-state creep behaviov of zirconium and zivcaloy-2 was examined in the temperature vatlge 520° to 620°C A1 low stresses the creep rates were cimracterized by a linear stress dependence; at highev stresses the stress dependence was much more pronounced. Temnperature-cycling tests yielded values for the aclivation enevgy for creep. Various tlzeories were examined in the ligltt of- the experimental re-sults and it mas concluded that the low-stress creep behavior is the result of the stress-direcled diffusion of vacancies along gain boundaries. It has been observed,"&apos; usually under conditions of high temperature and low stress, that creep deformation can occur for which the steady-state creep rate is linearly dependent on the applied stress. For magnesium and certain magnesium alloys, Harris and ones&apos; and ones&apos; have argued that this type of creep occurs by mass transfer as a result of the stress-induced generation and migration of vacancies, along a gradient defined by the stress direction. Jones&apos; demonstrated that the rate-controlling diffusion path is sensitive to grain size and temperature, and that by suitable control of these variables creep could occur by vacancy diffusion either predominately along grain boundaries or through the lattice. Recently, Jones3 suggested from an examination of limited high-stress data for zircaloy-2, composition in Table I, that significant diffusion creep could occur at low stresses, at least between 375" and 500°C, controlled by grain boundary vacancy diffusion. This process could have an important implication in assessing the role of zirconium alloys as a structural or cladding material in certain classes of nuclear reactors, since it predicts creep deformation far in excess of any estimates based on extrapolating slip creep data from higher stress levels. If the diffusion creep process occurs it should be possible to describe the total steady-state creep rate of zirconium and its alloys as the sum of two terms, Eq. [I]; the first term relates to a slip creep process important at high stresses and which is manifested by a much more pronounced dependence of creep rate on stress4 than diffusion creep and the second to a process controlled by mass transfer,5&apos;6 dominant at low stresses: where A and BI are parameters which can depend on structure, Ql and Q2 are the activation energies for the particular creep process occurring, and n describes the sensitivity of the creep rate on stress. It is the purpose of this paper to present some direct experimental evidence in support of this view. It is recognized that other analytical approaches have been proposed to explain data of this kind and these will also be discussed. 1) EXPERIMENTAL PROCEDURE Flat creep specimens (gage length 1 by 0.25 by 0.02 in. approx) were prepared from cold-rolled, argon-remelted, crystal bar zirconium and cold-rolled commercial-grade zircaloy-2, the analyses of which are given in Table I. The specimens were annealed at a pressure of < 10-5 Torr at temperatures from 625" to 675°C for 2 hr and slow-cooled. This treatment produced stable grains of average size (defined here by the average linear intercept) of for zirconium and -4xin. (-10 p) for zircaloy-2. The specimens were tested in a dead load tensile creep rig. The stress was maintained constant by adjusting the applied load after approximately each 1 pct of strain. The specimen temperature was controlled to better than +1°C. This system had a small thermal lag, so that rapid temperature changes were possible. To minimize corrosion, the specimens were tested in high-purity (99.95 pct) argon, further dried,

Jan 1, 1968

By J. P. Hirth, A. H. Clauer

A simple graphical method is presented for the determination of climb forces on dislocations exerted by uniaxial stresses. In conjunction with standard stereographic projections, the technique is applicable for any crystal system. Climb forces on glide dislocations in bcc crystals are determined as an application. In connection with a study1 of elevated temperature creep of molybdenum single crystals, a detailed analysis of the climb force on a dislocation was necessary. In general, such forces can be calculated for an arbitrary dislocation segment from the Peach-Koehler equation2 (or one of its variants3"6) where Fk are the components of the force per unit length of dislocation line, ?i of the unit sense vector tangent to the line, ojl of the stress tensor, bl of the dislocation Burgers vector, and is the Einstein permutation operator with components ?123 = ?231 = ?321 = —?132 = — ?321 = —?—213 = unity, and all other components zero. It is understood in the suffix notation of Eq. [I.] that repeated indices are to be summed over 1, 2, and 3. For the most general coordinate system, the matrix manipulations required to solve Eq. [I] are fairly complex. However, a simplification can be achieved by specifying a coordinate system based on the dislocation in question. The pertinent system involves cartesian coordinates xi, x;, xi, with attendant unit vectors e&apos;i; ei being parallel to the Burgers vector b, and e&apos;3; being parallel to the climb directions (b x ?), i.e., normal to the slip plane. In this coordnate system b = (bi, 0, 0) and ? = (?&apos;1,?&apos;2, 0). Hence, Eq. [I] yields for the climb force per unit length F3 = ?&apos;2s&apos;11b&apos;1—?&apos;1s&apos;12b&apos;1 [2] The first term on the right side of Eq. [2] is the climb force on the edge component of the dislocation, while the second is the (cross-slip) force normal to the glide plane acting on the screw component. Thus, the problem of determining the climb force reduces to that of resolving the stress components —il and s&apos;12 in the xi coordinate system. Several authors7- l0 have shown, for the glide case, that such stress resolution can be performed most readily by graphical methods. Therefore, we present a similar method for the climb case. Of the suggested methods, we follow that of Hartley and Hirth,9 which can be performed directly with a standard stereographic projection for the crystal system in question. We treat the case of simple tension, or compression, this being the most common creep test in which climb is important. A set of cartesian coordinates (x1, x2, x3) is fixed with x3 parallel to the specimen axis. This set is connected to the x&apos;i set by the factors defined in Table I. A perspective view of the coordinate systems relating them to the glide ellipse, is given in Fig. 1, while a stereographic projection of the coordinate systems is presented in Fig. 2. The transformation matrix connecting the xi and xi coordinates is x&apos;i =aijXj [3] where an a11 a13 aij = a21 a22 a23 a31 a23 [4] s The corresponding transformation for the stresses is i [5] The only nonzero component of okl for the simple tension case is s33,. Hence, using Eqs. [4] and 151, we find that Eq. [2] becomes F3 = b&apos;1s33 sin2 cos ?[cos ? sin a - sin ? cos a] [6] = m1b&apos;1s033 sin a- rn2b&apos;s33 cos a where sin a = 5: and cos a = ?i, with a the angle measured from b to ?, i.e., a polar angle in the x1, x2 plane. The same equation with a sign change applies for compression. A graphical plot of the "Schmid" factor m1, relating to the climb force on the edge component, is presented in the stereographic projection of Fig. 3. In this projection the glide plane normal points toward the top of the page and the glide direction points normal to the plane of the page. To use the graph, one

Jan 1, 1970

By G. M. Gordon, J. W. Spretnak, R. Speiser

AT present, considerable research is being directed toward the development of high-temperature, oxidation-resistant columbium alloys. Columbium. along with molybdenum and tungsten, exhibits good high-temperature strength. Unlike molybdenum and tungsten. however. columbium does not form a volatig oxide below 1375°c.l Although the outermost oxide formed on pure columbium, Cb2O3 is stable in air at elevated temperatures, it is not of a protective nature. It is porous and voluminous, and

Jan 1, 1959

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Jan 1, 1938

By Nicholas J. Grant, Michio Yamazaki

Cast copper alloys containing 10, 20, and 30 pct Ni and 0.75 to 0.80 pct Al were machine-milled into chips, then comminuted in a rod mill to fine flake powder utilizing a number of processing variables. The powders here internally oxidized, mostly at 800°C, in a low-pressure oxygen atmosphere. The consolidated powders were hot-extruded into bar stock. Room-tenmperature tension tests, stress-rupture tests mostly at 650°C, but also at 450° and 850°C, and hardness measurements after various annealing temperature treatments to study alloy stability were perfomted. Excellent room-temperature strength, high rupture strength at 650°C, and resistance to recrystallization at 1050°C were obtained. Problems in optimizing conditions for internal oxidation of Cu-Ni base alloys are discussed. THE interesting high-temperature properties of SAP&apos; have stimulated considerable effort in the study of more refractory alloy systems where the potential for high-strength alloys at high temperature is great.2-13 A number of methods have been utilized to produce the desired fine, hard particle dispersions, of which internal oxidation2,9,7 of dilute solid-solution systems offers considerable promise by virtue of the potential for producing ultrafine, well-dispersed oxides. While most of the published works are concerned with pure metal matrices, a number of investigators have studied the effects of solid-solution strengthening.10,19 Use of more complex alloy matrices (for example, aging systems) has been unsuccessful because overaging still occurs at high temperatures in the oxide-containing alloys.14.15 Solid-solution strengthening is, however, effective at very high temperatures9,10 and might be expected to contribute importantly to the strength of oxide-dispersion strengthened alloys. For this study, internal oxidation of solid-solution alloys of copper and nickel, containing small amounts of aluminum, was chosen as the method of alloy preparation. PREPARATION OF ALLOYS Three copper alloys containing about 10, 20, and 30 pct Ni and each containing 0.75 to 0.80 pct A1 (enough to yield about 3.5 vol pct alumina) were prepared as air-cast ingots measuring 2.5 in. diameter by 6 in. high (see Table I for the analyses). Processing steps for all the alloys were as follows (also see Table 11): 1) Homogenization of the ingot at 982°C (1800°F) for 45 hr in an argon atmosphere. 2) Machine milling of ingots into fine chips. Average thickness was about 0.1 to 0.2 mm. 3) Hydrogen reduction of chips at 593°C (1100° F) for 1 hr to reduce copper and nickel oxides. 4) Rod milling of chips to finer powders. 5) Hydrogen treatment of powders as in step 3. 6) Internal oxidation of the powders. 7) Hydrogen treatment of oxidized powders as in step 3. 8) Hydrostatic compression of evacuated powders. 9) Sintering of compacts in hydrogen. 10) Hot extrusion. Variations in processing among the alloys were made in steps 4, 5, and 10 (see Table 11). In the past, two methods were utilized to internally oxidize alloy powders. Preston and Grant3 surface-oxidized dilute Cu-Al powders to obtain the necessary amount of oxygen to oxidize the solute metal (aluminum and silicon), and then permitted the formed copper oxide to diffuse and react with the solute in an argon atmosphere. Bonis and Grant4 exposed Ni-A1 and other nickel alloys to an oxygen pressure derived from the decomposition of nickel oxide at a preselected temperature, in an argon atmosphere. Both methods are applicable and can be modified to generate a range of oxygen pressures for oxidation of the solute but not the solvent metals. Procedure I: Surface Oxidation of Alloy A3, Cu-10Ni-0.76A1. Powders of -20 to +28 mesh were surface-oxidized at 500°C (932°F) to obtain the desired amount of oxygen for oxidation of the aluminum to alumina; the powder was then sealed in Vycor and heated at 900°C (1652°F) for various times up to

Jan 1, 1965

By D. Krammer, E. S. Machlin

The effect of a brior high-temperature creep strain on the low-temperature ductility of commercially pure nickel has been evaluated. The low-temperature (-196°C) ductility decreases linearly with an increase in prior high-temperature (920°C) creep strain. The effect is experimentally correlated to the formation of inter crystalline cracks and voids during the prior high-temperature creep strain. The magnitude of the effect is also believed to be a function of the notch sensitivity of the material. SEVERAL mechanisms have been presented to explain the process of inter crystalline cracking in metals undergoing high-temperature creep. zenerl has suggested that grain boundary relaxation of shear stresses could build up high stresses at ob- stacles to grain boundary shear and thereby nucleate a crack. Chang and rant&apos; have experimentally demonstrated that cracks do form at obstacles to grain boundary shear such as lines where three grains meet. The role of vacancies in the mechanism of high-temperature inter crystalline cracking has been explored by Machlt with the conclusion that the nu-cleation of voids by vacancy condensation is almost

Jan 1, 1960

By D. E. Ranta, M. W. Ganster, A. D. Ward

An ore zoning technique developed by Climax geologists during the past forty years has been used to contour drill-hole assay values on cross-sections for fourteen porphyry molybdenum deposits in western North America, including the Climax and Henderson orebodies. Detailed geological studies of these large, complex deposits are essential in determining ore controls, which are the factors most critical to the zoning of MoS2 and to conceptualizing geologic model s. The technique provides a detailed representation of the size, shape, grade distribution, and geologic continuity of the individual deposits. It demands a disciplined approach and adheres to rigorous rules while maintaining flexibility for adaptation to widely varying geologic conditions. By defining the limits that guide and control manual, computer-assisted conventional, and geostatistical reserve estimates, it exerts a strong geologic influence on the estimation process. A combination of ore zoning and geostatistical analysis of molybdenum deposits produces a significantly more accurate, precise, and defendable geologic reserve estimate than other methods.

Jan 1, 1984

By G. A. Hellstrand

IN 1915, H. A. Guess, Vice President of American Smelting & Refining Co., in charge of its Mining Department, learned that the Anglo-New-foundland Development Co., Ltd., a pulpwood and paper-mill enterprise, had found upon its large concession in Newfoundland, and had opened up by shaft to the third level and some drifting, a lenticular orebody indicat-ing about 100,000 tons, as an extremely fine-grained sulfide ore, averaging about 0.05 oz. Au, 4 oz. Ag, 1.5 per cent Cu, 10 per cent Pb, 18 per cent Zn; and that having sent parcels of this ore to Minerals Separation, Ltd., and various other metallurgical testing concerns without obtaining any success in commercial separations thereon, had discontinued work thereon and let the workings fill. Mr. Guess wrote to the general manager of that company and obtained a few hundred pounds of the typical ore, which he sent to his company&apos;s metallurgical testing laboratory at Flat River, Mo., outlining various flotation tests desired thereon, in an endeavor to obtain separation into a commercial lead concentrate and a zinc concentrate. But the art of flotation had not then progressed far enough to treat such ore, the galena and zinc blende being so fine grained that grinding to about 300 mesh was required to release the mineral particles in their gangue. Mr. Guess had flotation and other tests continued upon this ore from time to time with whatever new reagents and flotation devices were evolved as time went on, and finally, in 1925, he succeeded in effecting in his company&apos;s testing plant, then at Wallace, Idaho, separations into lead concentrates and zinc concentrates of satisfactory commercial grade. Mr. Guess then proceeded to unwater, examine and sample the property and made with the owners a partnership operating agreement upon the mine itself and a considerable area surrounding it, and in the early summer of 1926 began to prospect for additional orebodies, utilizing for such prospecting geophysical methods, under the direction of Hans Lundberg, methods which up to that time had been little used in mining in the western hemisphere.. This geophysical work found two large flat-lying orebodies of a type precisely similar to the smaller body of the original discovery. The larger orebody, some 3500 ft. west of the original

Jan 1, 1934

By Donald B. Evans, Robert D. Pehlke

The solubility of nilrogen in liquid binary alloys of iron with Litanium. zivconium, columbium, vanndiurn, and tantalum was measured for alloy composiLions up to the solalbility limils of lhe alloy nitrides. All five alloying agents were found to decrease markedly the activity coefficient of nitrogen in liquid ivon. The metal/nitvogen mole ralios in the alloy nitrides formed were generally .found to be slighlly greater than 1.0, but in no case greater than 1.5. From the experimental data, the standard free energies of fortmation of titanium and zir-conium nitrides have been calculated for the Lemperaluve range 1550° to 1750 C. The solublily Products for columbium, tantalum, and vanadium nitrides are also reported. A number of research investigations have examined the effect of refractory metals on the solubility of nitrogen in liquid iron. Although data on zirconium are not available, investigators are in agreement that titanium, vanadium, columbium, and tantalum markedly increase the solubility of nitrogen in liquid iron. This fact alone makes desirable the acquisition of thermodynamic data for these elements in liquid iron. Since refractory metals are known to be stable nitride formers, they have been suggested as steel denitrifying agents, and some of their nitrides have recently been considered as containment materials for liquid iron and iron alloys. Most available thermodynamic data for these metals relate to their dilute concentrations, but effective thermodynamic treatment of these applications requires data at concentrations near the solubility limit of the alloy nitride. Although some work has been done at relatively high alloy concentrations in liquid iron (particularly for vanadium 2,3 and titanium 2,4), the results have been somewhat contradictory. Disagreement may be partly attributed to the fact that the compositions of most refractory metal nitrides have been shown to be nonstoichiometric, and to vary 2,5-8 depending on the temperature and nitrogen gas pressure with which the solid nitride phase is in equilibrium. One purpose of this study consequently has been to determine the compositions of the refractory metal nitrides precipitated from a liquid iron solution. EXPERIMENTAL PROCEDURE Rao and Parlee2 and Evans and Pehlke 9 have discussed the technique for measuring the solubility product of an alloy nitride phase in liquid iron by finding the point of departure of the nitrogen solubility from Sieverts&apos; law. The method consists of measuring the solubility of nitrogen in a melt of iron containing a known concentration of a second metal as a function of the nitrogen gas pressure over the melt. In this study the second metal was one of the refractory metals titanium, zirconium, columbium, vanadium, or tantalum. When the nitrogen pressure at which the refractory nitride forms is reached, a deviation of the measured solubility of nitrogen in the melt from Sieverts&apos; law is observed in the form of a "pressure halt." The concentration of nitrogen in the melt associated with this breakpoint in the nitrogen-absorption curve is then used to calculate the nitride solubility. The Sieverts method was used to measure nitrogen solubility as a function of nitrogen pressure and temperature. The experimental equipment for this technique has been previously described in detail. 1,9 Charge materials used were vacuum-melted high-purity iron (Ferrovac-E) and the best commercial grades of the refractory metals obtainable (in all cases at least 99.8+ pct pure). Recrystallized alumina crucibles were used to hold all melts except those containing zirconium, for which zirconia crucibles were necessary. Temperatures were measured by a disappearing-filament type optical pyrometer sighted vertically downward on the melt surface through a 1/4-in.-diameter sight hole in the crucible lid. By means of a technique previously described, 9 in which the refractory-metal nitride was precipitated at one temperature then redis-solved by raising the temperature 50°C and precipitated again at a higher temperature, it was possible to obtain data over a temperature range of up to 200°C on a single melt. It was found that this technique could not be used with melts containing zir-

Jan 1, 1965

By William E. Galloway, Gary E. Smith, Christopher D. Henry

INTRODUCTION Studies relating to the Oakville aquifer as presented in this report and by Henry et al. (this volume), are part of a larger , comprehensive examination of regional and local stratigraphic, hydro- geologic, and geochemical parameters within the Oakville Formation recently completed by the Bureau of Economic Geology. The Oakville serves both as a major Gulf Coast aquifer and an important uranium host (Fig. 1). Regional and local controls on hydrodynamics and hydrochemistry have important implications for hydrochemical exploration, the establishment of premining baseline parameters, and the design of post mining restoration procedures. Investigations of the Oakville Formation were de- signed for the purpose of determining the response of the aquifer to uranium extraction and were funded by the U.S. Environmental Protection Agency under grant numbers R-805357-01 and R-805357-02. Physical Stratigraphy Physical stratigraphic analysis shows that the Oakville Sandstone, a lithostratigraphic unit deposited by a major coastal-plain f luvial system, consists of five mappable, component depositional elements (Figs. 2 and 3). Each major component element is the product of one or more rivers traversing the Miocene coastal plain. In turn, each river possessed a unique sediment load, discharge characteristics, and source terrane. Consequently, each element exhibits distinguishing geometric and compositional parameters that potentially influence the flux and hydrochemical evolution of contained ground waters (Galloway, Henry, and Smith, in preparation). The Oakvil le Sandstone, as mapped and interpreted as a lithostratigraphic unit in the study area, corresponds closely to the Jasper aquifer system, an equally well-defined Gulf Coastal Plain hydrogeologic unit (Baker, 1978). Principal surrounding hydrogeologic units include the underlying Catahoula confining system, the Jasper aquifer system itself, and the overlying Burkeville confining system (lower Fleming mudstones). The Evangeline aquifer system includes much of the Fleming Formation. The Jasper aquifer system is bounded above and below by relatively less transmissive, finer grained confining systems, although absolute transmissivity varies greatly within both the Jasper and confining units. Lithostratigraphic and hydrogeologic boundaries coincide almost exactly within the Hebbronville flu- vial axis (Fig. 3). Correspondence of geologic and hydrostratigraphic boundaries is good within the George West axis; farther to the northeast the correlation of the Jasper aquifer with units mapped as Oakville Formation diverges to varying degrees. A complete analysis of these trends and a study of the depositional facies comprising the Oakvillle are included in Galloway, Henry, and Smith (in preparation). REGIONAL HYDROGEOLOGY The stratigraphic, compositional, and structural framework of the Oakville Formation and the mosaic of interrelated depositional facies that are combined in this framework play a key role in defining the hydrogeology of the Oakville. Furthermore, a combination of climate and hydrogeology, as well as past and present socioeconomic conditions, has determined water and land use patterns within the region of Oakville outcrop. Utilization of Oakville Ground Water Stratigraphic control for determining which wells produce ground water from the Oakville aquifer was established by preparing structural and isopach maps of the Oakville Formation using regional electric log cross sections. Surface elevation and screened interval data (or total well depth, if open-hole completion techniques were used) from each water well, combined with the stratigraphic data, allowed accurate assessment of the producing aquifer for individual wells. Information on well and screen depths, water levels, and usage of water from

Jan 1, 1980

By Donald C. Barton

OF the four papers that comprise this Technical Publication, three are case histories of individual geophysical prospects, subsequently tested by drilling. The bibliography of Dr. Barton&apos;s published scientific paperst includes investigations in physiography and surface geological mapping, as well as his geophysical papers, and from this list it is to be observed that he early recognized the place of different types of geophysical prospecting methods in the search for geological structures of economic importance. Moreover, his viewpoint was not merely that the structures should be found, but that the geophysical data should be examined quantitatively to determine the geometry of the structures. In other words, that although these data are insufficient to deduce a unique form for the structure that caused the effects measured in the data, the engineering computations should be carried out to give as much of a definite configuration to the structure as the data permitted, in order that the testing of the structures could be conducted in the most economical manner and with the idea that the experience so gained could be later incorporated in the study of structures subsequently found. Dr. Barton continually emphasized the quantitative use of geophysical observations, whereas at the time that he began his specialization in geophysics it was considered sufficient to use observations only qualitatively. He, more than any one else, was responsible for the first volume on geophysical prospecting issued by the Institute in 1929, and his three articles in that volume stressed the quantitative use of geophysical prospecting. The fourth article in this present Technical Publication is a further contribution to this branch of geophysical interpretation, and is a supplement to the paper in the 1929 volume, "Calculations in the Interpretation of Observations with the Eötvös Torsion Balance." From the successful demonstration by Dr. Barton of the usefulness of quan-

Jan 1, 1946

By Donald C. Barton

OF the four papers that comprise this Technical Publication, three are case histories of individual geophysical prospects, subsequently tested by drilling. The bibliography of Dr. Barton&apos;s published scientific paperst includes investigations in physiography and surface geological mapping, as well as his geophysical papers, and from this list it is to be observed that he early recognized the place of different types of geophysical prospecting methods in the search for geological structures of economic importance. Moreover, his viewpoint was not merely that the structures should be found, but that the geophysical data should be examined quantitatively to determine the geometry of the structures. In other words, that although these data are insufficient to deduce a unique form for the structure that caused the effects measured in the data, the engineering computations should be carried out to give as much of a definite configuration to the structure as the data permitted, in order that the testing of the structures could be conducted in the most economical manner and with the idea that the experience so gained could be later incorporated in the study of structures subsequently found. Dr. Barton continually emphasized the quantitative use of geophysical observations, whereas at the time that he began his specialization in geophysics it was considered sufficient to use observations only qualitatively. He, more than any one else, was responsible for the first volume on geophysical prospecting issued by the Institute in 1929, and his three articles in that volume stressed the quantitative use of geophysical prospecting. The fourth article in this present Technical Publication is a further contribution to this branch of geophysical interpretation, and is a supplement to the paper in the 1929 volume, "Calculations in the Interpretation of Observations with the Eötvös Torsion Balance." From the successful demonstration by Dr. Barton of the usefulness of quan-

Jan 1, 1946

By J. Kent Smith

THE object of this investigation was to ascertain the effect of varying percentages of beryllium upon pure copper and the properties of the resultant alloys in their softest condition, the effect of heat hardening on them, and the extents to which these properties could be augmented by different combinations of heat hardening and cold rolling. The data compiled in this paper represent partial results of continuing work done by the writer during the years 1930 and 1931, which was a continuation of the unpublished ground work incepted in the laboratory of the Beryllium Corporation of America by H. B. Pulsifer in the year 1926. A short bibliography on beryllium alloys is appended to this paper. It has, of course, long been known that copper subjected to cold work is hardened and strengthened to a considerable extent, furthermore it had been qualitatively noted in previous experiments that copper-beryllium alloys seemed to take on hardness and strength as the result of cold work at a greater rate even than does plain copper. It was decided therefore to endeavor quantitatively to determine such rate of increase, as also the relative increases by combinations of cold working and heat hardening. The results are summarized in Tables 3, 4 and 5. A preliminary series of experiments had indicated that by an exposure to the heat of 575° F. for 2 1/2 hr. age-hardening of a 2.50 per cent beryllium-copper alloy took place. Slab ingots of nine different beryllium-copper alloys were prepared under identical conditions by means of the addition of a previously prepared 12.5 per cent beryllium-copper alloy to well melted and deoxidized pure copper. The ingots were then reduced by hot rolling to 12 gage (about 0.080 in.). These strips were heated to 1450° F. and quenched in cold water, and thus brought to their softest condition. (See Table 1.) Strips were next "precipitation-hardened" by reheating to a definite temperature. Similar strips to those itemized in Table 1 (which had been quenched from 1450° F.) were reheated for varying periods of time at 575° F. The hardness figures show that a metastable condition, of which the range of stability is dependent entirely upon time at the given temperature, begins to be noted in copper samples containing as little as 0.85 per cent beryllium. It is extremely noticeable in samples containing

Jan 1, 1932

By L. C. Brown, E. B. Hawbolt

The formation of grain boundary precipitates has been studied in Ag-5.64 wt pcl Al alloys at 688°C. Large-grain specinzerzs were used and the boundary misorientation measured by X-ray diffraction. At low-angle grain boundrrries Primary sideplates form. u)hile abore a 17-deg misorientation lenticular precipitates predominate. Growth of the lenticular precipitates was studied on individual grain boundaries using a statistical technique. The thickening and lengthening rates appeared to be independent of &apos;pain boundary misorientation, indicating that grain boundary diffusion was not significant in this system. The precipitates grew urith constant shape, with both the length and thickness increasing parabolically with time. The parabolic lengthening rates were unexpected since previous theory and experimerztal results had indicated linear growth. By approximating the shape of the precipitate to that of an oblate spheroid grouling with constant shape an equivalent diffusion coefficienl was calculated. The zlalue obtained was in good agreement with nleasurements obtained fron, diffusiorz couples. IF a single-phase alloy is heated or cooled to a temperature such that the phase becomes supersaturated, there is a tendency for a second phase to precipitate from it in order to remove the supersaturation. Precipitation takes place initially on grain boundaries due to preferred heterogeneous nucleation, but subsequently Widmans kitten plates may form in the grain interiors if the grain size and supersaturation are sufficient. The type of grain boundary precipitate formed depends on the nature of the boundary. Aaronson1 and clark2 have shown that grain boundary misorientation can be characterized by the simple parameter R, where and X, Y, and Z represent the minimum rotations about three orthogonal axes required to bring the two lattices forming the grain boundary into coincidence. The maximum value for R is 60 deg. In using this parameter the orientation of the grain boundary itself is, of course, neglected. However it was found in both Fe-si3 and A1-Ag2 that the precipitate shape depended only on the parameter R. Clark found that the vast majority of precipitates formed were allo-triomorphs— lens-shaped precipitates that grew along the grain boundaries. At low-angle boundaries, however, (R < 15 deg) Widmanstatten sideplates nucleated at the grain boundaries and grew into the adjacent grains. It has been reported that the rate of growth of grain boundary precipitates is controlled by diffusion within the supersaturated phase.&apos; The theories which have been developed for growth rates have assumed the diffusion coefficient constant over the composition range of the supersaturated phase. This is a fairly good approximation if the composition range involved is not large. Thickening rates have been calculated using the theory developed by Zener4 and by Frank5 for the growth of planar precipitates. A parabolic growth law

Jan 1, 1968

By S. C. Sun, John A. L. Campbell

The surface properties exhibited by bituminous coal and bituminous coal lithotypes were ascertained by using streaming potential techniques. The electro kinetic prop-erties wereascertainederties of bituminous coal were found to be similar to those of anthracite. The principle electrokinetic properties of the coal and lithotypes, zero-points-of-charge (ZPC), and potential determining ions, were established. The effects of indifferent electrolytes, hydronium and hydroxyl ion sources, and polyvalent ions (cationic and anionic) were also evaluated. Location of the ZPC&apos;s with respect to pH is discussed in terms of chemical and mineralogical composition of the respective surfaces. To account for the observed electrokinetic phenomena, a generalized surface model and adsorption mechanism are proposed. Surface-dependent processes, such as froth flotation and flocculation, are important or potentially important techniques for combating some of the current major problems in coal preparation. In order to correctly apply or improve a surface-dependent process, it is of paramount importance to understand the interfacial phenomenon, especially the double layer properties, exhibited by the solid. The specific objective of this research was to determine the properties of the bituminous coal/liquid interface by an electrokinetic method, streaming potential, and to relate the findings, wherever possible, to the existing unit operations of froth flotation and floccula-tion tion. The electrokinetic properties of both the whole coal and its lithotypes were investigated. As part of the total investigation, the role played in the double layer by the reagents commonly employed in the surface dependent process was also established.&apos; These data will be presented at a later date. Experimental Procedures The coal samples used in this research and their designations are listed in Table 1. The classical description of humic coal lithotypes as developed by Stopes" was used for the delineation of the lithotype samples. The samples were taken from the working face of a producing deep mine of the Pittsburgh seam in the area of Ellsworth, Pa. To avoid oxidation, only freshly exposed areas were sampled. The normal precautions against contamination were also exercised. Two types of samples were taken, specimens rich in a particular lithotype and a representative channel sample. The latter sample was prepared for analyses by grinding it to —35 mesh. It was screened repeatedly during the grinding to provide the largest amount of 35 x 48-mesh (standard Tyler sieves) material possible. The screened fraction was passed over a magnet and then washed several times with distilled water and finally with conductivity water. The resulting sample now termed "whole coal" was stored under conductivity water in a glass bottle. Pure lithotypes were obtained from the lithotype concentrates by hand picking, and were processed in the same manner as the representative sample. Maceral analyses, employing standard petrographic procedures," were performed on the lithotype samples to determine the purity of the samples. The results are presented in Table 2. Reflectance measurements of the vitrinites and fusinites are also reported in this table. Proximate and ultimate analyses of the samples are given in Tables 3 and 4. The electrokinetic properties of the coal samples were determined by streaming potential methods.&apos;-&apos; All of the chemicals used in the investigation were reagent grade (Baker analyzed). The conductivity water was prepared by doubly distilling the water in a pyrex Yoe-type still and passing the distillate through a mixed bed ion exchange column. Results In general, the electrokinetic properties of the investigated bituminous coal were found to be similar to the results of a previous study of anthracite by Camp-bell bell5 and are in accord with the suppositions of Brown." The zeta potentials of the coal and all the lithotypes were found to be negative in conductivity water. Jowett? in a study of slime coatings on coal also found bituminous coal to exhibit a negative surface. Fig. 1 shows that the negative charges, at neutral pH&apos;s, for both fusain and the gangue are very small, almost zero, while at the same pH, vitrain has the largest negative charge, almost 30 mv. Durain has a negative charge of 17.5 mv. The determination of the affect of pH on the charge of the coal surfaces revealed that hydronium and hydroxyl ions apparently behave as potential determining ions; however, they do not appear to be potential determining for the gangue. These results are illustrated in Fig. 1. As the pH of the solution was decreased, hydronium ions were adsorbed, causing the surface of the coal to reverse polarity and become

Jan 1, 1971

By L. A. Mekler

The recirculating furnace is primarily a heating apparatus of the convection type in which the heat-absorbing surfaces are heated by a mixture of fresh products of combustion and a portion of the combustion gases that have already given off a part of their heat in their previous passage over the heat-absorbing surfaces. In its basic conception, the recirculating furnace can be considered as a closed thermal system in which the heat-absorbing surfaces are constantly swept by a fixed quantity of products of combustion at a given initial temperature with the gases being constantly returned to the furnace and reheated before they again enter the heating zone. Gases equal in amount to those produced by the fuel burned to reheat the circulating gases are constantly ejected from the system to the stack. The recirculating furnace is the most suitable apparatus for heating by convection where low furnace temperatures must be maintained and where only a small portion of the available heat is taken out of the gases, particularly where the maximum allowable furnace temperature is low and where the final temperature of the gases is only a few hundred degrees below their initial temperature. In such cases, recirculation not only provides a method of reducing the rather high combustion temperatures of the fuel when burned without a large amount of excess air, but, by returning to the furnace the heat content of the gases at their final temperature, recovers a large portion of heat that otherwise would have been lost through the stack. The convection-type oil still is particularly suitable for the application of flue-gas recirculation. In an oil still, the heating of the oil is accomplished by applying to the tube surfaces a given quantity of heat of a certain predetermined quality, usually with the initial temperature of the gases not over 1500" F. as measured by thermocouples placed above the tube bank. To obtain the full benefit of the heating surface of the coil, the final temperature of the gases, after passing over the coil, is kept 200" to 300" higher than the temperature of the incoming oil. This final temperature varies from 500" F. for a topping still with only a slight or no

Jan 1, 1928