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By C. H. Mathewson, A. U. Seybolt

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrellce of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below. Conditions of Equilibrium between a Metal and Dissolved Oxide at Different Temperatures and Pressures The general conditions of equilibrium in any system are conveniently summarized in a projection of the triple curves of the P, T, X space

Jan 1, 1935

By A. U. Seybolt, C. H. Mathewson

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrellce of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below. Conditions of Equilibrium between a Metal and Dissolved Oxide at Different Temperatures and Pressures The general conditions of equilibrium in any system are conveniently summarized in a projection of the triple curves of the P, T, X space

Jan 1, 1935

By W. R. Wawersik, A. M. Starfield

The classical approach to room-and-pillar mine design in flat-lying, tabular ore bodies limits itself to the special case of an extensive and uniform system of pillars. Each pillar is then assumed to carry the same load, and this load is readily calculated from the extraction ratio e and the weight of the overburden : average pillar stress = [ ] where H is depth below surface, p is average density of overburden, and g is acceleration due to gravity. The average pillar load does not, in this case, depend on the mechanical properties of either the pillars or the surrounding rock mass. The only relevant physical property of the pillars is their compressive strength, (i.e., the maximum load-carrying ability) and the criterion for design is that the average pillar stress should not exceed this strength. The wider the pillar, the greater its strength, and the design of the system is concerned with reconciling this increase in strength to the requirements of roof control so as to optimize extraction.l Any departure from a uniform distribution of pillar loads invalidates the classical approach. Such departures may, for instance, be brought about by: (1) a nonuniform layout of pillars and remnants resulting from selective mining, (2) variations in geology which result in gross changes in the properties of part of the seam or the host rock, (3) deliberate use of abutment support in narrow panels, and (4) the use of yielding pillars for local roof support in conjunction with barrier pillars to carry the overburden load.

Jan 1, 1972

By AIME AIME

At the Annual Meeting of the Institute, February, 1908, the following amendments to the Constitution were proposed for action at a future business meeting (see Trans., XXXIX, xxvii) To Art. II. After the first sentence of this Article, add the following sentence « These classes may be subdivided by the Council, according to profession, length of membership, nationality, or other conditions not inconsistent with the provisions of this article." To Art. III. In the first line, substitute " fifteen " for "ten " dollars. At the Annual Meeting of February, 1909, action upon these amendments was postponed to the next business meeting (see Bulletin No. 27, March, 1909, p. xiv). Of these two amendments, the first has been withdrawn, as unnecessary-the subdivision thereby authorized being already practicable without such amendment. The second amendment will be acted upon at the next Annual Meeting, February 15, 1910, and the Secretary has been instructed to call the attention of members to the subject in such a way as to secure a general vote upon it. A special circular, now being prepared by the Secretary, will shortly be sent to all members. Year Book of the Institute. The Year Book of the Institute for 1910 is sent to all members and associates with this issue of the Bulletin. In addition to the lists of members enrolled Jan. 1, 1910, and arranged both alphabetically and geographically, this annual contains lists of officers, council, corporation, past officers, meetings, and notices concerning publications; also the constitution and by-laws of the Institute, and blank forms for proposal of mem-

Jan 1, 1910

By O. Hoover, M. Herman, V. V. Damiano

The Jetter and borie' teclznique of determining textures using a spherical specimen has been applied to tlze study of compression-rolled beryllium sheet. Snzall spheres the order of 1 mm in diam cut from the beryllium sheet were autotnatically rotated about tz41o axes using the G.E. single-crystal goniometer. Quantitative pole figures were obtained without tke need to apply absorption corrections. Compression-rolled beryllium exhibited peak intensities ,for (0002) planes of positions tilted 10 deg to the rolling plane and a near random distribution of (1010) planes about the nornal to the rolling plane. TECHNIQUES for determining textures of rolled sheet material are amply described in the literature. The techniques are found to be variations of two basic methods. One due to Decker, Asp, and arker, referred to as the transmission method, utilizes a thin-sheet specimen in which the X-ray beam enters the specimen from one side and the intensity of the beam which emerges from the opposite side is measured. The second method due to chulz,3 referred to as the reflection method, utilizes a thick specimen and the intensity of the beam emerging from the same side is measured. The two rotations of the specimen in the beam are designated a and 8. In order to completely determine the texture of sheet material, it is generally necessary to use a combination of the two methods. The calculations involved in correcting the raw X-ray data for absorption effects and the combining of the data obtained by the two methods are very laborious and time consuming. To avoid the intensity corrections which arise as a result of the changing diffraction volume and path length within the sample other methods have been proposed. The Norton method utilizes a cylindrically shaped specimen cut from the sheet material. Since the rods have rotational symmetry, the absorption correction is constant for rotations about the sheet texture. Jetter and Borie' employed a spherical specimen to analyze the fiber texture of extruded aluminum rods. The spheres were rotated rapidly about the fiber axis to include a large number of grains in the X-ray beam and changes in intensity with respect to tilts of the fiber axis were measured. The absorption correction was constant for all angles and was neglected. The Jetter and Borie' technique finds excellent ap- plication to very fine-grained low-absorbing metals in which the entire sphere volume can contribute to the diffraction volume. In the case of low-absorbing metals, however, serious limitations on specimen thickness occur as demonstrated by Braggs due to de-focussing effects. Peak shifts may occur which negate the assumption that integrated intensities are proportional to peak intensities. These limitations in sphere size to the order of 0.5 to 1 mm for beryllium require that the grain size be sufficiently small to include a large enough statistical sample. The present paper describes the application of spherical specimens less than 1 mm in diam to the quantitative determination of pole figures for compression-rolled beryllium sheet having a grain size the order of 10 p. EXPERIMENTAL 1) Specimen Preparation. Two techniques for spark-machining beryllium spheres were tried. One involved the use of a hollow cylinder as a cutting tool. The tool was fed into the rotating cylindrical specimen as shown in Fig. l(a). The hollow cylinder was carefully aligned such that the axis of the cylinder and the axis of the specimen lay in the same plane and were 90 deg to each other. As the hollow cylinder was fed into the rotating cylindrical specimen, a spherical shape was formed as shown in Fig. 1. Alignment was very critical. Slight misalignment resulted in the formation of a barrel-shaped specimen instead of a sphere. A second technique involved the use of a cutting wheel shaped as shown in Fig. 2 with a groove of the desired radius. A section of the sheet specimen was first turned into a cylinder on the left part of the cutting wheel. It was then shifted to the right and a spherical specimen was turned as shown in Fig. 2. The axis of the cylinder lay in the plane of the sheet. Flats corresponding to the rolling plane of the sheet were used to grip the specimen during the machining operation and these served to identify the rolling plane of the sphere. 2) Rotation of Spec=. The spherical specimen is shown mounted on the G.E. single-crystal goniometer in Fig. 3. The knob A of the goniometer shown in Fig. 3 rotates the specimen about the pedestal axis. These angles have been designated as @ angles. The knob B rotates the specimen about an axis perpendicular to the pedestal axis. These angles have been designated as p angles. A device was made to automatically drive the single-crystal goniometer by means of two flexible shafts connected to the A and B knobs as shown in Fig. 3. The motor system was designed to rotate the knob A, thus rotating the specimen through angles of $I while the B knob remained stationary. After one complete

Jan 1, 1967

By P. Wynblatt, J. E. Dorn

The effect of strain rate, temperature, and interstitial impurity concentration on the flow stress was investigated in a poly crystalline Fe-2 pct Mn alloy. The temperature dependence of the flow stress was found to be independent of the interstitial impurity concentration, removal of interstitials merely decreasing the atherma1 stress level. Below 160%, the large temperature dependence of the flow stress was interpreted in terms of the Dorn-Rajnak theory of the Peierls mechanism of plastic deformation. Above 160"K, some other thermally activated intrinsic meckanisln seems to be operating. The strong temperature dependence of the flow stress of bcc iron at low temperatures has been studied by numerous investigators and interpreted in terms of several different thermally activated dislocation mechanisms. The following mechanisms have been proposed: a) interaction of dislocations with interstitial impurity atoms1 or with solute atoms in general; b) interaction of dislocations with clusters of impurity atoms;3 c) resistance to the motion of dislocations due to jogs on screw dislocations;* d) resistance to the motion of dislocations due to the Snoeck effect;' and e) interaction of dislocations with the intrinsic resistance of the bcc lattice or Peierls "hills". In previous work: it was found that the plastic behavior of polycrystalline iron containing 2 wt pct Mn (and 100 ppm C + N) is in good agreement with predictions based on the Peierls mechanismlo from 77" to 160°K whereas from 160" to about 370°K another as yet unidentified thermally activated mechanism is operative. The purpose of the present investigation was to determine the effect of interstitial impurities on the temperature dependence of the flow stress, by purifying the previously investigated alloy with respect to interstitial impurities. The investigation revealed that removal of the interstitial impurities to a level that eliminated Cottrell locking and the Portevin-LeChatelier effect (i.e., serrations in the stress-strain curve due to dynamic strain aging) affects neither the strong temperature dependence of the flow stress at low temperatures nor the general characteristics of the higher-temperature behavior. Such purification, however, lowered the athermal yield stress. I) EXPERIMENTAL PROCEDURE AND RESULTS The material used in this investigation consisted of an Fe-2 wt pct Mn alloy having the following additional elements present: 0.004 pct C, 0.006 pct N, 0.05 pct 0, 0.004 pct S, 0.003 pct P, and 0.001 pct Si. This was the same material as that studied in the previous investigation and will henceforth be referred to as the "impure material". The as received -jr by 2 in. hot-rolled bars were cold-rolled to 0.08-in. thickness, recrys-tallized under argon for 30 min at 80O0C, and further cold-rolled to 0.053-in. thickness. Flat tensile specimens 3 in. wide having a 1.625-in.-long gage section were machined from the sheet and then purified. The first stage of purification consisted of holding the specimens at 850°C for 24 hr in a stream of hydrogen saturated with water vapor at room temperature. Material prepared in this fashion will subsequently be referred to as "wet hydrogen purified material". It has been estimated that this type of treatment reduces the carbon content of iron to less than 5 ppm.' The second stage of purification consisted of holding the specimens in a closed system through which hydrogen was circulated past the heated specimens as well as a zirconium hydride getter. The specimens were held at 850°C and the getter at 800°C. The process was continued for 212 hr. The starting material for this process was wet hydrogen purified material. Material prepared in this manner will be referred to as "ZrHz purified material". The technique used was substantially the same as that described by Stein et al.' who have shown that the carbon level at the end of the process is reduced to about 5 parts per billion. The mean grain size of the three materials was found to be -60 C( for the impure material and -160p for the wet hydrogen and ZrHz purified materials. All tensile testing was carried out on an Instron Testing Machine either in controlled-temperature baths or at fixed-point baths such as boiling liquid nitrogen, and so forth. When fixed points were used the temperature was kept constant to better than *1°C whereas in all other tests the temperature variation was less than *2°C. Test of Purity. It was not possible to determine the purity achieved at each stage of the purification because the resulting level of interstitial impurities was near or below the limit of sensitivity of standard analytical techniques. It was possible, however, to obtain a qualitative measure of the extent of purification from the appearance of the stress-strain curves for the three materials. Fig. 1 shows the stress-strain curves for the three different materials tested at 300°K. It can be seen that the effect of wet hydrogen

Jan 1, 1967

By J. R. O’Connor

Stimulated emission from Nd+3 in yttrium uanadate fYVOJ is reported. Single crystals of YVO4:Nd, obtained from Linde Col-p., have improved substantially in the last several months. Pulsed thresholds of YVO, laser rods are now approximately 2 to 3 5, cowparable to tliose for YAG:Nd. Yttrium uanadate crystalli~es irz a space group similar to zircon. All rare-earth vanadates have this structure. Rare-earth ions sucll as Nd+3 which substitutes for Y+3, aye situated irz a strong tetragonal crystal field which lacks inversion symmetry. This condition increases the p'robability of the parity-forbidden f — f transitions. Yttrium anadate has strong absorption bands beyond -1000A. These are clue to Y-O, V-O charge transfer and molecular transitions. Under 2537 and 3660A irradiation pure YVO, fluroresces u bright yel-LOLO. This fli&orescence is corrzpletely quenched in YV04:Ncl crystals. This and other evidence of energy trut~sjer from the lattice is repovted. Optzcul atz 1user pvope 1-ties o! YI'U4:E[t are brieJy described. THIS paper describes some of the optical and laser properties of Nd+3- and Eu+3-doped yttrium orthovana-date (YVO4). It reports laser action for the first time in this low-symmetry host. For some time we have pursued a research program concerning laser hosts' wherein the rare-earth (RE) ion is situated at a site of low crystal symmetry so as to increase the probability of radiative transitions. Single crystals of doped and undoped YV04 are grown from iridium crucibles in an oxyhydrogen gas-fired furnace by a modified Czochralski technique.' This material crystallizes in a D4li tetragonal space group of the zircon (ZrSiO,) type.3 All RE vanadates have the same structure and form solid solutions with YVO4. Therefore, it will be possible to investigate a variety of cross-pumped laser systems, as in the case of yttrium aluminum garnet (YAG).4 At present, ~d'~-doped YAG is one of the most efficient solid-state lasers.5 Accordingly, most of the material to follow will compare the properties of YV04 to those of YAG. Fig. 1 shows the relative transmission of YAG and two types of YVO4. "Pure" YVO4 has a normal absorption edge and is colorless. A second type has a broad absorption peaking near 4200A and is yellow. Rubin and Van uitert6 suggest the yellow material is slightly reduced. Samples of each type are being investigated by electron spin resonance,7 but these studies are so far inconclusive. The pulsed laser threshold is much lower in the yellow material than in the colorless. Therefore, the absorption at 3500 to 5000.4 transfers energy to the Ndi3 ions. Photons of wave length between 2000 and 4500A cause undoped YVO4 to fluoresce at 4800, 5250, 5460, 5540, and 5750A. This emission, previously reported by Brixner and Abramsom,8 is partially quenched by EU'~ and completely quenched by Ndt3 at room temperature due to energy transfer from the lattice to the RE ions. At low temperatures, some lattice fluorescence is present. This implies that the energy-transfer process is in part phonon-assisted. Although the YVO, single crystals used in this work were prepared from Y2O3 containing less than 0.01 pct rare-earth impurities, there is aopossibility that emission lines between 4800 and 5750A are due to dysprosium, terbium, and so forth. However, these lines are not observed in other compounds, prepared from Y2O3, such as YP04, Y2MoO6, and so forth. Furthermore, extensive absorption measurements on our "pure" YV04 single crystals between 0.4 and 5.0 failed to reveal any characteristic rare-earth lines. Fig. 2 compares the absorption spectra of Ndt3-doped YAG and YVO4from 0.6 to 1.0 . The Ndt3 absorptions are labeled according to free ion, R-S coupling. These term designationsQ are appropriate for YAG:Nd. They appear to be inappropriate for YV04:Nd. In YVO, neodymium must substitute for yttrium. The yttrium site is situated In a strong tetragonal field, where point symmetry is (42m) or possibly lower.1° However, the reduced splitting of the Stark components of the YV0,:Nd spectrum implies that the NdT3 ion is in a cubic site. The only plausible explanation for this discrepancy is that the Ndt3 ion is in a low-symmetry site, lacking inversion symmetry, so that a substantial admixture of 4f and 5d wave functions occurs. In this case, R-S coupling is not valid and J is no longer a good quantum number." Consistent with this view, the 4~ metastable level of YV04:Nd has an oscillator strength larger and a

Jan 1, 1968

By John F. Burst

GENETIC correlations of the various types of Cheltenham fireclays found in Missouri have been the subject of several papers. The correlations usually have been attempted on the basis of stratigraphic and leaching patterns (Wheeler,18 1896; Allen, 1,2 1935 and 1937; McQueen,13 1943). Herold10 (1943), as well as Allen,l,2 has dealt at length with the mineral¬ogy of Missouri fireclays and postulates genetic relationships from min¬eralogical findings. Both researchers cite kaolinite as the primary clay mineral of the Cheltenham formation and suggest that differences in physical proper¬ties are due to clay mineral impurities such as halloysite or illite (not recog¬nized by the name "illite" at the time of Allen's papers). By ascribing the differences to impurities, it is possible to use weathering as the only major alteration factor. This paper seeks to probe still farther into the clay mineral composition of the Cheltenham formation and to show thereby that the mineralogical differ¬ences that have been found to exist within the "kaolinite" component of the Cheltenham fireclay may alter somewhat the previously held theories of diagenesis. Two Missouri fireclays, which have been rather thoroughly investigated, were chosen for comparison of genetic relationship to clay mineral content. One is a typical plastic fireclay of the middle Cheltenham (McQueen's classification13) obtained at Mexico, Audrian County, Missouri, from a large open pit operated by the A. P. Green Fire Brick Co. The other-a typical hard flint fireclay-was obtained from a pocket deposit in southwestern Mont¬gomery County, Missouri.

Jan 1, 1952

C. E. Dewey, Georgetown, Colo. (communication to the Secretary) : In his remarks on crushing-machinery, Mr. Douglas says (Twins., xxii., p. 322): "To insure a smaller and more uniform size of particles in the crushed material, the Dodge crusher still communicates motion to the upper extremity of tile movable jaw, which oscillates on fixed pivots projecting from its lower extremity!' The notion that, in order to obtain a fine and uniform product from a rock-breaker, the movable jaw must be pivoted at its lower extremity, seems to obtain generally among mill-men, as well as among manufacturers of machinery. My experience with machines of both types does not confirm this belief. It is true that, to obtain a uniformly fine product from a jaw-crusher, the stroke at the lower extremity of the crushing-surface must be short; but that the movement at that end must be less than at the other or receiving-end is, I think, an erroneous assumption. Figs. 1 and 2 are intended to illustrate the two types of machine. It is found in practice that the capacity and the nature of the product of either machine, as usually constructed, are governed by the opening, C D, and the length of stroke of the movable jaw at D. This being the case, machines of either type, of the same width of crushing-surface, running at the same speed, and having the same adjustment as to opening and stroke at D, should give, when fed

Jan 1, 1895

A group of prominent engineers and contractors of Chicago and vicinity have cooperated in forming a Joint Committee on Military Engineering. The founders are members of all of the leading engineering and contracting organizations of Chicago, including the local branches of the national engineering societies. The purposes of the Committee are to further military preparedness among engineers, contractors and their associates by the following means: (1) Courses of lectures; (2) assigned reading; (3) studies and practical instruction in military engineering;. (4) assisting engineers to qualify as officers in the National Reserve Corps of Civilian Engineers; (5) urging enlistment in and support for engineer troops of the National Guard and such other organizations as the Government may create; (6) furthering instruction in military engineering in training camps and the attendance in them of those qualified; (7) by such other means as from time to time may be deemed advisable. The Joint Committee has already prepared a program covering the vital points outlined. To date the program is practically complete for a period extending from April 20 to July 25. Something of interest will be taken up each week, including lectures by Lieutenant-Colonel W. B. Judson, Engineer Corps, U. S. Army; two lectures by Major P. S. Bond, Engineer Corps, U. S. Army; Lieutenant-Colonel Mason M. Patrick, Engineer Corps, U. S. Army, and several exhibition drills, terrain exercises and inspection trips under the direction and guidance of various officers of the Engineer Troops of the Illinois National Guard. Additions to the program will be made from time to time. '

Jan 5, 1916

SOUTHERN CALIFORNIA SECTION Executive Committee SEELEY W. MUDD, Chairman. C. COLCOCK JONES, Vice-Chairman. FREDERICK J. H. MERRILL, Secretary-Treasurer, 631 Higgins. Bldg., Los Angeles, Cal. RALPH ARNOLD A. B. CARPENTER A. B. W. HODGES WILLIAM F. STAUNTON The third meeting of this winter season tool: place in a private dining room of the Sierra Madre Club in Los Angeles on Feb. 1, 1916, at 6:30 p.m., 22 members and guests being present. In the absence of the Chairman, S. W. Mudd, the Vice-Chairman, C. Colcock Jones, presided. After an enjoyable dinner the meeting was called to order, and the first paper by Ralph Arnold on Conservation of Oil and Gas in the Americas was read by the Secretary. W. F. Staunton then read an important paper on The Influence of California Oil on the Mining Industry of the West. In this he touched upon the uses of oil as a fuel for generating power, especially in connection with the Diesel engine. This paper was discussed it some length by J. F. Mitchell-Roberts, R. B. Moran, F. H. Asbury and L. D. Godshall. The Chair then introduced Robert B. Moran of the California State Mining Bureau, Deputy Supervisor of Gas and Oil, for the' Los Angeles . District, who addressed the meeting on the work of his department. The meeting concluded with A. B. Carpenter's reading of a paper on The California Gasoline Industry by W. R.. Hamilton, Manager of the Ventura Refining Co. F. J. H. MERRILL, Secretary. ,

Jan 4, 1916

A group of prominent engineers and contractors of Chicago and vicinity have cooperated in forming a Joint Committee on Military Engineering. The founders are members of all of the leading engineering and contracting organizations of Chicago, including the local branches of the national engineering societies. The purposes of the Committee are to further military preparedness among engineers, contractors and their associates by the following means: (1) Courses of lectures; (2) assigned reading; (3) studies and practical instruction in military engineering;. (4) assisting engineers to qualify as officers in the National Reserve Corps of Civilian Engineers; (5) urging enlistment in and support for engineer troops of the National Guard and such other organizations as the Government may create; (6) furthering instruction in military engineering in training camps and the attendance in them of those qualified; (7) by such other means as from time to time may be deemed advisable. The Joint Committee has already prepared a program covering the vital points outlined. To date the program is practically complete for a period extending from April 20 to July 25. Something of interest will be taken up each week, including lectures by Lieutenant-Colonel W. B. Judson, Engineer Corps, U. S. Army; two lectures by Major P. S. Bond, Engineer Corps, U. S. Army; Lieutenant-Colonel Mason M. Patrick, Engineer Corps, U. S. Army, and several exhibition drills, terrain exercises and inspection trips under the direction and guidance of various officers of the Engineer Troops of the Illinois National Guard. Additions to the program will be made from time to time.

Jan 5, 1916

Noranda Mines, of Quebec, signed a contract for construction of a $20 million copper refinery at Gaspe, P.Q. The plant is expected to have a 65500-ton daily capacity for both concentrator and smelter. Extensive drilling. around Gaspe has revealed more than 65 million tons of 1 to 2 pct copper in several deposits. Cerro de Pasco Corp. has called a special stockholders meeting for August 19 to obtain permission to engage in the oil and natural. gas business, in addition to its present production of zinc, lead, copper, silver and other metals. St. Joseph Lead Co. recently entered the oil development field. The United States, Canada and Great Britain have agreed to establish a permanent organization to work on unification of engineering standards. General accord has been reached on drafting standards and practices, screw threads, fittings for gas cylinders, and fits and tolerances. Permanent committees will study these fields. Reconstruction Finance Corn approved the largest sum in its history. for a mining enterprise when it loaned $94 million to San Manuel Copper. Corp., of Pinal County, Ariz. The loan will be used to increase production of copper and molybdenum, in what was described as-the biggest copper deposits in the country. Three large gold mining concerns operating in the Philippines told the Philippine Wage Board that they would be forced to close if they had to boost miners' wages 500 to $2 per day. The companies are Mindanao Mother Lodes, Benguet Consolidated, and Balatoc Mining Co.

Jan 1, 1952

By John Chipman, Daniel Dutilloy

The equilibrium of gaseolis H2O-H2 mixtures with liquid iron-phosphorus alloys in the range 0 to 3 pct P is used to establish the increuse of the activity coefficient of oxygen, in the presence of phosphorus. Two different sampling techniques are used. THE importance of oxygen as a refining agent in steelmaking operations makes it desirable to improve our understanding of its behavior. Phosphorus which is always present in the ores has adverse effects on steel properties and its removal is necessary. The present study was undertaken to evaluate the interaction of oxygen and phosphorus in molten iron. Bookey, Richardson, and welch1 have studied the phosphorus-oxygen equilibria in liquid iron in the presence of lime. They used a mixture of hydrogen and water vapor to control the oxygen potential and worked with crucibles made of tetracalcium phosphate and lime. At low phosphorus concentration, i.e., at high oxygen, they observed a marked deviation in their results. They tentatively ascribed this to a large negative effect of oxygen on the activity of phosphorus. This was then included by chipman2 in his review of interactions in liquid iron. Pearson and Turkdogan 3 have later reported an interaction parameter They equilibrated a mixture of hydrogen and water vapor with an iron-phosphorus alloy contained in an alumina crucible and sampled the melt by suction in a silica tube. The solubility of oxygen in iron-phosphorus alloys has been studied by Levenets and Samarin.4 They reported an interaction parameter

Jan 1, 1961

By L. L. Davis

The rapid increase in the use of pulvcrulent adsorptive materials in the so-called "contact filtration" process for decolorizing lubricating oils makes it desirable to consider some of the basic principles involved. The commercial methods and types of equipment now used arc fairly well known, having been extensively described in the trade journals. In spite of this very little has been published concerning the factors which must be considered in the selection of a process or of a decolorizing ing material. It is commonly understood that contact filtration more or less closely follows the laws of adsorption. These principles have been thoroughly drscribed by Gurwitsch.' The contacting of neutral mineral oils seems to be adsorptive in character and apparently follows Freundlich's law of adsorption which may be expressed by the formula: X = Color material adsorbed hy the clay. M = Amount of clay used. C = Concentration of color material after equilibrium. A and P = Constants for a given oil and clay. Fig. 1 shows the decolorization curve for a natural, dark colored cylin-der stock when contacted with various quantities of clay, curve R being made with natural Riverside Texas fuller's earth and T being made with an acid-treated clay from Texas. As the Tag-Robinson color is inversely proportional to the depth of color, the reciprocal of these colors ran be assumed to be a funct ion of the concentratlion of coloring matter. The values of and C' can, therefore., br calculated by using the reciprocal Tag-Robinson colors, and when these

Jan 1, 1928

By J. T. Raleigh, D. L. Flock

This study investigated the nature of formation plugging with bacteria and attempted to relate its characteristics to physical rock properties. Fifteen core samples of four specific formation types were defined and plugged using a commonly occurring, uniform sized dead bacteria, Bacillus subtilis. Two of the formation types were fairly uniform-grained sandstones and two were heterogeneous carbonates. The injection rate and concentration of solids in the brine were held constant during the test runs. The pore geometry factor G was a significant petro-physical rock characteristic for correlation with depth of plugging, but lacked importance as a parameter for rate of plugging. Although the G factor may not completely describe porous rock geometry for plugging predictions, for reservoirs with multi-pore systems, there is evidence that the pore geometry factor might form a basis for establishing injection water specification in more llornogeneous reservoirs with only primary porosity development. INTRODUCTION GENERAL PURPOSE Injecting water into oil-bearing formations to increase recovery is common practice in the petroleum industry. One of the most serious operational problems involved with water injection wells is the tendency of the porous rock immediately adjacent to the injection wellbore to plug partially. This results in increased injection pressures and/or a decrease in the rate of injection. This plugging in injection wells can result from a number of causes, including bacteria contained in the injected water.1 The purpose of this work was to investigate the nature of injection plugging with bacteria and to attempt to relate its characteristics to physical rock properties. Many variables exist in research of this type, so, to reduce them, injection rate and concentration of bacteria in brine were held constant. The bacteria used for plugging was a uniform-sized, dead bacteria, Bacillus subtilis, a micro-organism commonly found in water, air and soils. Four specific porous rock types were plugged—two consolidated sandstones and two heterogeneous carbonates. The experimental work involved two distinct phases. The first concerned determining the physical rock properties and the second was the experimental work of actually plugging the selected core samples. PORE GEOMETRY FACTOR Capillary pressure is necessary to displace a wetting fluid from a capillary opening with a nonwetting fluid. The factors which govern capillary pressure are the surface or interfacial tension of the fluids involved, the system wettability and the equivalent pore radius. Thus: P,= 2ucososrd..........(1) Thomeer used the idea that the location and shape of the capillary pressure curve reflect characteristics of the pore structure of any porous media sample.' He presented the mathematical description of capillary pressure curves and of indicated differences in pore geometry of samples. where G = pore geometry factor PC = capillary pressure Pi = displacement pressure (V,)p, = fractional bulk volume occupied by the displacing fluid at any capillary pressure (V,), = fractional bulk volume occupied by the displacing fluid at infinite pressure or total interconnected pore volumes. The shape of the curve is defined by the pore geometry factor G. The curve shape is related directly to the sorting and interconnection of the pores of the sample. The location of an infinite number of curves can be defined by the same asymptotes. However, these curves differ in shape, each curve being described by a specific value of G. Thus, the description of a curve is unique when, in addition to the position of its asymptotes, its shape is defined. These curves can be used graphically to determine the characteristic parameters of any arbitrarily located curve. Those parameters that can be approximated from any capillary pressure curve are: (1) total interconnected pore volume, represented by (V,),- ; (2) extrapolated displacement pressure, the abscissa axis; and (3) pore geometry factor, by the curve shape. PROPERTIES OF BRINE AND BACTERIA The fluid used throughout this study was an aqueous solution of sodium chloride, 25,000 ppm by weight. The addition of salt to fresh water was intended to eliminate clay swelling in the sandstone cores and to retard leaching in the limestone cores. The viscosity of the brine solution at 100F, the temp-

Jan 1, 1966

By S. R. Balajee, I. Iwasaki

The interaction between British gum 9084 and dode-cylammonium chloride (DAC) at quartz and hematite surfaces was established from coadsorption studies and streaming potential measurements. The cationic DAC interacts with the somewhat anionic British gum 9084, leading to the formation and adsorption of a binary complex of DAC-British Gum 9084 at the interface. The parallel ability to depress quartz along with hematite as a result of the interaction between DAC and British gum appears to be the main reason for the ineffective depressant action of starches and starch derivatives in the cationic flotation of iron ores. Amines are not particularly selective collectors for the flotation' of siliceous gangue from iron ores and, therefore, a suitable iron oxide depressant is needed for a satisfactory separation. Various starches and their derivatives have been extensively tested with oxidized iron ores,'-3 and it has been empirically established that British gums and dextrins are preferable. However, for the flotation upgrading of magnetite-taconite concentrates from 8 or 8.5% Si O2 to about 5% Si 02, British gums, which have been used so successfully on oxidized iron ores, have been found to have no effect and oftentimes are actually deleterious.4 In previous articles,5-7, starches were shown by adsorption measurements, flotation tests, and floccula-tion tests to interact with calcium ions in solution, and it was thought that a study on the interaction between starches and dodecylammonium ions would be able to shed some light on the anomalous flotation behavior described above. In fact, starches are known to interact markedly with paraffin-chain-type surface active agents and, thereby, to precipitate the starch or inhibit the iodine-starch reaction.8 From X-ray diffraction studies and viscosity measurements, the formation of a helical complex between mylose and a surface active agent has been postulated.9 The interaction with other types of hydrophilic colloids, such as synthetic polymers and proteins, has also been investigated and is usually explained in terms of van der Waals' force interaction and/or ion-ion interaction. In the present investigation, the interaction of British gum and dode cylammonium chloride on quartz and hematite was studied by adsorption and streaming potential measurements in an attempt to establish the mutual adsorption behavior of British gum and dode-cylammonium chloride on mineral surfaces and to clarify the anomalous depressant activity of British gum in the cationic flotation of iron ores. All the measurements were carried out at a natural pH of near 7 because dodecylammonium chloride gives maximum selectivity of flotation separation at this pH2 and to avoid any third parameter in the system. EXPERIMENTAL MATERIALS AND METHODS Minerals: The quartz and hematite samples used for the adsorption tests were prepared as described in a previous paper,"J except that the specific surfaces of the samples were increased to 5,860 and 16,000 Sq cm per gm, respectively. For the streaming potential measurements, the 48165-mesh fractions screened out of the original samples were etched with hydrochloric acid, washed repeatedly with water, and stored under water in Pyrex bottles. Reagents:DodecyIammonium chloride (DAC) was prepared1 1 by bubbling dry hydrogen chloride gas through a benzene solution of high-purity dodecylamine supplied by Armour and Co. British gum 9084, received from Corn Products Co., was solubilized by first dispersing it in water to produce a 0.05% solution and then homogenizing it in a blender for 5 min. Distilled water was used in the preparation of the samples and the solutions and for all test work. Adsorption Measurements: The procedure for the adsorption density determinations was also the same as that described in the previous paper.1° The residual concentrations of the British gum and the DAC in the supernatant solution were analyzed colorimetrically by the phenol-sulf uric-acid and amine-picrate methods, respectively. The validity of the mine-picrate method for the colorimetric analysis of DAC in the presence of British gum and the analysis of British gum in presence of DAC were checked by establishing calibration curves between optical density and concentration. Streaming Potential Measurements: The cell assembly for the streaming potential measurements was similar to that described by Fuerstenau.' The streaming potential

Jan 1, 1970

By L. S. Darken

Measurements of the electrical conductivity, the thermal electromotive force, and the deviation from stoichiometry by thermogravimetry were made on ferrous oxide (wüstite) single crystals as well as on poly-crystalline samples in the temperature range of -900" to 1330°C. In the region defined by T 2 1000°C and 1.05 5 O/Fe 5 1.10 the electrical conductivity was shown to be proportional to the sixth root of- the oxygen partial pressure and to be linearly dependent on the deviation from stoichiometry. The absolute Seebeck coefficient of single and polycrystalline wüstite was shown to be independent of temperature in the above region and a p to n transition of the Seebeck coefficient was observed at O/Fe = 1.09 in polycrystalline wüstite. Analysis of the results showed that the predominant defects in wüstite in the above region were doubly ionized cation vacancies. The analysis also ruled out the existence of complexes of the type postulated by Roth, except that below 1000°C there is some evidence of 'association of defects. Of the three oxides of iron (FeO, Fe3O4, Fe2O3) only FeO (wüstite) can exist within a wide range of the ratio O/Fe. This has been shown by several investigations of the phase diagram using for instance chemical analysis of quenched samples'-4 or thermogravimetric measurements. 5,8 Darken and Gurry's1 data for example in the temper- ature range 1100o to 1400°C show that the lowest O/Fe ratio obtainable for FeOl +. is about 1.045 and that the existence range extends to O/Fe = 1.20 at 1400oC. On the basis of detailed analysis of thermogravimetric measurements made by Vallet and Raccah6 the existence of three varieties of wüstite at elevated temperatures was suggested by these authors and by Kleman. It is well-established that wüstite has a NaCl structure with vacant cation sites.3, 8 From a neutron-diffraction study of wüstite samples quenched to room temperature Roth9 concluded that defects in wüstite are mostly complexes composed of two cation vacancies and one interstitial cation in a tetrahedral site. The atomic arrangement in the vicinity of such a defect is similar to that in magnetite, where each occupied tetrahedral site is surrounded by four vacant octahedral positions disposed at the corners of a tetrahedron, so arranged that each vacancy is shared by two tetrahedral cations. Thus there is an average of two vacancies per interstitial. Recent X-ray diffraction measurements made by Smuts10 on quenched wüstite samples confirmed the results of Roth's neutron-diffraction experiments. Roth's model of defects in FeO can be regarded as a solid solution of Fe3O4 in FeO; salmon1' used this defect model to calculate the activity of Fe3O1 in FeO at high temperature and claimed good agreement with the results obtained experimentally by Darken and Gurry.' Each missing cation in wüstite is accompanied by two trivalent cations, thus preserving charge neutrality. The "holes" which differentiate between the Fe 2+ and Fe3' states of the ions in octahedral positions can overcome the attractive field of the cation vacancies, and are then free to move through the crystal as charge carriers. A similar picture holds for COO, NiO, andMnO.l2, 13 Localization of the charge carriers in transition

Jan 1, 1968

By T. Vasilos, J. T. Smith

THE mechanism of pressure sintering, or hot pressing, for ceramic materials, has been investigated by several researchers.1-8 Plastic flow has been suggested as the rate-determining mech-anism1,2 while grain boundary sliding3,4 and fragmentation processess have been found controlling in other studies. Vasilos and Spriggs5,6 have reported that pressure sintering occurs by a diffusion-controlled mechanism. For the pressure sintering of metals, investigations with lead7 and with tin6 have not identified the operative mechanism during consolidation of these powders. This note reports the results of a pressure sintering study initiated to determine the mechanism controlling the densification of spherical copper powder. Temperatures of 300°, 400°, 500°, and 600°C at 2500, 5000, 7500, and 10,000 psi pressures were investigated. The copper powder for this study was obtained from Metals Disintegrating Co., Elizabeth, N.J. The minimum purity was reported to be 99.9 pct. The powder size was -325 mesh and a lineal analysis showed the average size to be less than 1 p. An alumina die body and punches were employed. Graphite spacers were placed between the copper powder and the punches before pressing. It was expected that the graphite would form carbon monoxide with any entrapped air and form a reducing atmosphere within the die cavity. This condition was generally realized during pressing although a minor amount of oxidation occurred at 500" and 600°C. The oxide particles were located randomly in the pressed samples and were not considered to influence the densification process. Calibration tests showed the temperature of the copper pellet to be about 20°C less than the die wall temperature, probably resulting from heat losses through the punches. This difference was compensated during the experimental pressing operations. The hot pressing equipment employed for this work has been described by Spriggs et a1.9 and was calibrated with a Baldwin-Lima-Hamilton load cell. Travel of the punches was monitored with a dial indicator showing increments of travel to 0.0005 in. Relative density was calculated at selected time intervals for a known copper weight, punch travel, and die diameter. The accuracy of this calculation was *1 pct. Average grain size after hot pressing was obtained by lineal analysis. Typical densification curves are presented in Fig. 1 and Fig. 2 where relative density is plotted vs log time as a function of applied pressure for the 300" and 600°C pressure sintering temperatures, respectively. The curves for 400" and 500°C were similar to those at 300°C and consequently are not shown. The curves at 300°C as well as 400" and 500°C do not show an end-point or limiting density for a particular applied pressure. At 600°C, a density in excess of 95 pct of theoretical has been reached such that further densification is extremely slow for the 5000, 7500, and 10,000 psi pressures. It is suggested that further densification at these pressure levels may be retarded or prevented by discontinuous grain growth, by entrapped gases, and by other microstructural limitations as described by Cob1e.10 The curve for 2500 psi hot pressing pressure is a straight line over the time interval although a slight change in slope may be occurring at the last time intervals. The plastic flow models,1,2 derived for hot pressing, predict the existence of an end-point (or limiting) density dependent on the yield point of the material at the temperature of interest. The yield stress of copper at a 0.005 strain level has been

Jan 1, 1965

By S. J. Rothman, J. J. Hines, D. Rokop, R. Bastar

Self-diffusion has been measured along each principal axis of mosaic-structured and relatively perfect a uvaniuln single crystals. The anisotropy reported before,' D[loo] = D[001] » D[010 , has been confirmed. and is shown to represent volume diffusion. Diffusion along the dislocations in the imperfect crystals increases the measured value of D significantly without changingr either the shapes of the penetvation plots or the anisotropy. SINCE a uranium is orthorhombic, the diffusion coefficients along the principal crystallographic axes need not be equal. A previous measurement of self-diffusion in three mosaic-structured a uranium single crystals1 showed that Dil00| =D[001 >>D[010 This result was deduced from penetration plots similar to those in Fig. 1. That is, the plots for diffusion along [loo] and [001] were the straight lines expected from the solution of the diffusion equation for the boundary and initial conditions of the experiment, while the plot for diffusion along [010] was curved so that the part near X = 0 had a much steeper slope than the straight lines did. The observed anisotropy could have been due either to volume diffusion or to diffusion along the very large number of dislocations in such crystals, according to the model proposed by aart.' The authors of Ref. 1 argued that the latter possibility was unlikely, but did not exclude it. To settle the question, a simultaneous measurement of self-diffusion in mosaic-structured and mosaic-free crystals was carried out. This paper reports the results, as well as a measurement of the temperature dependence of self-diffusion in a uranium. EXPERIMENTAL The single crystals of a uranium used in this experiment are listed in Table I, together with other experimental details. '(Mosaic structured" here means crystals grown by solid-state phase change.3 The Laue spots from such crystals spread over about 6 deg of arc, which indicates that the density of dislocations is very large. "Perfect" crystals are ones grown by Fisher's grain-coarsening tehnique; the Laue spots from these are quite sharp,4 which shows that the dislocation density in these crystals is much lower. All of the crystals were made from high-purity uranium; a typical analysis is given in Ref. 1. The actual diffusion directions were within a few degrees of the nominal. The thin layer-sectioning method was used. The experimental techniques were similar to those described in Ref. 1, except the sectioning. Crystals Za, 2b, 2c, 4a, 4b, and 4c were sectioned on a lathe. Crystals 3a, 3b, and 3c were sectioned by grinding on glass plates, with 1 p diamond powder in butyl alcohol as the abrasive. The use of glass plates eliminated the crowning noted in Ref. 1, and the use of butyl alcohol as a lubricant simplified the chemical processing of the sections. Material from the sides of these three crystals was removed by spark machining before sectioning. The sectioning of crystals 4a and 4c was botched. A small cylinder of metal was extruded from the center of crystal 4a while turning off material from the side of the sample. Crystal 4c was misaligned by 2.1 x 10"3 cm because the dial gage jammed during the alignment. Notwithstanding these errors, useful data were still obtained from these crystals. The points

Jan 1, 1967