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By J. C. M. Li

The steady state shape of a shrinking cylindrical grain boundary of miform boundary energy is shown to be circular. This is based on the principle of either the minimum rate of entropy production or the minimum thermokinetic potential. The circular shape corresponds also to a state of minimum (not maximum) velocity. The steady state shape of a grain boundary moving between two inclined surfaces is a circular cylindrical arc whose position and curvature will be afjected by the nature of the surfaces. The minimum thermokinetic potential is the only valid criterion in this case. THE preceding paper1 reports an interesting experiment in which it is shown that a grain boundary moving between two inclined surfaces assumes a circular cylindrical arc whose axis nearly coincides with the line of intersection of the two surfaces. The driving force is well defined since it is the energy of the grain boundary itself. The velocity of the grain boundary is found not to vary linearly with the driving force. Several interesting questions arise: 1) What principle determines the shape of a moving grain boundary? 2) What is the effect of the inclined surfaces? 3) How do we understand the nonlinear velocity-driving force relationship? It is attempted in this paper to discuss the first two questions based on irreversible thermodynamics and in a following paper to discuss the third question based on dislocation theory. STEADY STATE SHAPE OF A SHRINKING LOOP (A CYLINDRICAL GRAIN BOUNDARY) In irreversible thermodynamics, there are two criteria for the steady state. One is the minimum rate of entropy production2 which is based on the symmetry of phenomenological coefficients and is applicable to linear force-flux relations with constant coefficients. The other is the minimum thermokinetic potential3 which is based on the integrability of a certain Pfaffian differential equation and is applicable to nonlinear systems with variable coefficients. In the case of a shrinking grain boundary loop (a two dimensional version of a cylindrical grain), the flux of atoms across the grain boundary can be taken as the local boundary velocity v measured perpendicular to the boundary (the number of atoms transferred per unit area per second is equal to the product of atom density and the velocity of the boundary). The local thermodynamic driving force can be taken as y/p with y being the grain boundary energy (invariant with respect to the orientation and curvature of the grain boundary) and p being the radius of curvature. Such driving force can be understood by considering the loop as an elastic string with tension y. As shown in Fig. 1, across a length ds along the loop, the direction of y changes by an angle d@ which is ds/p. Because of this change of direction, the tension exerts a force perpendicular to the curve equal to yd@. The force per unit length is then y/p. According to the experimental observation, the velocity v is a power function of y/p, where M is the velocity at unit driving force and 'n is a constant. The rate of entropy production per ds along the loop is vyds/pT, where T is the temperature. For a given length L of the loop, the total rate of entropy production is The thermokinetic ptentia13 has only a differential definition and its existence depends on the integrability of this definition. In this case, Eq. [3] happens to be a total differential and the thermokinetic potential can be defined as which turns out to be the same as the rate of entropy production, Eq. [2], except for a constant factor n + 1. Strictly speaking, since the flux-force relation is not linear, the rate of entropy production may not be a minimum at the steady state. However, because of the proportionality between Eqs. [2] and 141, the state of minimum thermokinetic potential happens to be the same as that of minimum rate of entropy production. The steady state shape thus can be obtained by minimizing either integral [2] or [4] for a given L.

Jan 1, 1970

By W. C. Thurber, C. J. McHargue

THE deformation textures of metals have been extensively studied because of both the practical implications in metal fabrication and the fundamental insight into the behavior of the metal during deformation. Most studies have been concerned with pure metals or solid-solution alloys and relatively little attention has been directed toward more complex alloy systems. Barrett' and Brick2 have summarized work on multiphase systems in terms of the relative ease of deformation of the phases. Thus, if the phases are deformed about equally, each develops its usual texture for the particular fabrication process. This behavior has been reported for Ag-Cu and Cd-Zn alloys3 and 62-38 brass.4 A dispersion of hard particles in a softer matrix interferes with the normal reorientation of the matrix lattice during deformation, thus distorting the texture or in some cases preventing its development. Increasing the amount of carbon in steel has been observed to increase the randomness of the ferrite5 and almost random textures have been reported for A1-12 pct Si eutectic alloy wires.6 It has also been noted that if the second phase is platelike, deformation causes the platelets to line up in a common direction. The present work concerns a quantitative study of the deformation textures in aluminum-uranium alloys containing 5 or 13 wt pct U. Alloys in this composition range are characterized by a pure aluminum matrix in which the intermetallic compound UA14, is dispersed. From a fundamental standpoint, this system affords the opportunity for studying the effects of a dispersed phase on texture development in an essentially pure metal matrix. Further, these alloys are commonly used as fuels for nuclear research and testing reactors, and a knowledge of the preferred orientation may be useful in evaluating physical and mechanical properties as well as response to fabrication. The deformation textures in sheets of aluminum (99.996 pct), Al-5 pct U alloy, and Al-13 pct U alloy were determined for reductions in thickness of 90 pct by cold rolling. The texture in an alloy rod of the latter composition which had been extruded at 455°C was also determined. It can be readily ascertained from the aluminum-uranium phase diagram that the 5 pct U alloy is hypoeutectic and contains 7.3 wt pct (3.4 vol. pct) UAl4. The 13 pct U alloy has the eutectic composition and contains 18.9 wt pct (9.4 vol. pct) UAl,; however, because of nonequilibrium solidification conditions, the typical eutectic microstructure was not developed. The alloys were prepared by open-air melting in graphite crucibles. The slab castings were cropped and cold reduced 90 pct in thickness on a two-high mill. The slabs were reversed after each pass. Although the uranium-bearing alloys exhibited edge cracking, they could be cold rolled to the desired thickness. Small coupons 1.5 by 0.75 by 0.1 in. thick were sheared from the center of the rolled plate with a major axis parallel to the rolling direction. To obtain a specimen of sufficient thickness for machining of the X-ray diffraction specimen, three coupons were laminated into a single three-ply sandwich with a suitable adhesive. Adhesives which could be cured at room temperatures were selected in order to prevent recrystallization during bonding. Bondmaster M-648 (Rubber and Asbestos Corp.) was used for the pure aluminum laminate and Armstrong A-6 (Armstrong Products Co.) was used for the alloys. The alloy for extrusion was cast in a cylindrical graphite mold! cropped and machined into a 3-in. diam by 4-in. long billet. This billet was preheated to 455°C, upset to 3.125 in. diam, and extruded on a 700-ton hydraulic press at a speed of 6 fpm through a flat-face, 1-in. diam die. The rod was quenched with a water spray as it emerged from the die. Pole-distribution data were obtained using the diffractometric method described by Jetter and Borie.7 A spherical X-ray diffraction specimen of

Jan 1, 1961

By A. Long, A. Silverman, J. L. Kulp

Garth Crosby has written an excellent geologic description of the deposits surrounding the Gem stocks in the Coeur d'Alene district. The ore deposits in the area of the Gem stocks may hold the key to the age and mineralization history of the entire Coeur d'Alene district. A recent isotopic study10 of the Coeur d'Alene district in this laboratory illustrates that a classical geologic interpretation of these deposits, with its implications for the whole district, may lead to erroneous conclusions. For this reason it seems pertinent to submit a summary of these results and an interpretation of the mineralizing history of the Coeur d'Alene districts. Pitchblende from the Sunshine mine has been dated as 1100-1200 million years (m.y.) by Kerr and Kulp,11 and Eckelmann and Kulp.12 This pitchblende is known to predate the major sulphide introduction in the Sunshine mine, but it clearly follows the metamorphism and folding of the Belt Series. Recently, Goldich (personal communication) dated sericite from the Belt rocks as 1200 m.y. by the potassium-argon method. This date establishes a minimum Belt age if the sericite is of metamorphic origin and a maximum age if detrital. The Belt Series, therefore, is not latest Precambrian. Lead isotope ratios of galenas have been measured and model ages calculated by Bate, et all3 for the Sunshine mine, Farquhar and Cummingl4 or the Bunker Hill and Sullivan mine, and Cannonl6,18 for a few other deposits in the district. Galenas from similar deposits in Southern British Columbia have been measured by Bate, et al,23 Farquhar and Gumming,11 and Wanless and Leech." The new work in this laboratory includes leads from ten widely scattered mines north and south of the Osburn fault, and through a vertical distance of over 5000 ft (Star mine). Included in this group are the Hercules, Sunset, and Mountain Goat mines, which are adjacent to the Gem stocks. In addition, galenas from stringers which cut the Gem stocks in the Success and Sunrise mines and the Hercules hanging wall dike in the lower western portion of the Hercules mine, were included in the study. All of the above leads, except one, give model ages of 1300-1400 m.y. for the time of segregation from the parent material. The concordance of the common lead and U-Pb ages, the great horizontal and vertical uniformity of the lead ratios, the sulphur ratios of two Sunshine mine galenas and three galenas from the Edith, Page, and Hercules mines indicating average crustal sulphur, and the U23/Pb204 ratio inferred for the original lead environment, indicate that the entire mineralization of the Coeur d'Alene-British Columbia base metal belt was derived from a deep source and emplaced in the Precambrian. One sample of galena from sulphide stringers cutting the North Gem stock at the Sunrise Prospect mine gave a modern (i.e., Tertiary) lead ratio. This mine is located at the northern tip of the stock. The presence of modern lead suggests mobilization of some rock lead during the intrusion of the Gem stocks and their outliers. Larsen et al.l8 have dated the Gem stocks as Tertiary by the lead alpha method. If Coeur d'Alene mineralization was genetically related to Tertiary magma formation and intrusion

Jan 1, 1961

The papers discussed in the following pages were presented during two sessions of the Geophysics Education Committee of the Mineral Industry Education Division on Feb. 17 and 18, 1941. At the first meeting, to consider the "Influence of Geophysics upon Geology Curricula," this Committee was joined by the Geophysics and Mining Geology Committees of the A.I.M.E., the Society of Economic Geologists, representatives of the American Geophysical Union, and delegates from the Committees on College Curricula and on Applications of Geology of the American Association of Petroleum Geologists. Quentin D. Singewald and Sherwin F. Kelly presided. At the ensuing session, especially emphasizing the integration of geology, physics and chemistry for the solution of earth problems, the joint participants with the Geophysics Education Committee were the Geophysics Committee, and representatives of the American Geophysical Union and of the Committee on College Curricula of the American Association of Petroleum Geologists. Richard M. Field and W. R. Chedsey presided. In the following summary of the discussion at the two meetings, written discussion submitted subsequently is not differentiated from that offered orally at the session. A provisional report of the Geophysics Education Committee was presented at the second session, and some of the following discussion refers to it. This report has not been printed (it is anticipated that a more comprehensive, final one will be rendered at the 1942 annual meeting), but a few mimeographed copies of this provisional report are at the A.I.M.E. headquarters and will be mailed on request. . Dr. W. P. HAYNES presented some notes prepared by Dr. F. H. LAHEE, Chairman of the American Association of Petroleum Geologists' Committee on College Curricula. This Committee's inquiries reveal the general opinion that a four-year academic preparation is inadequate, five or six being advisable. The fundamentals, mathematics, physics, chemistry, and English composition, should be stressed in the first three years, with specialization in the last two or three years. Some companies provide an apprenticeship period, and themselves give additional training.. During academic years more attention needs to be given to engineering training, to field mapping, and in geology to stratigraphy and sedimentation. The amount of mere memory work should be cut, and men trained to observe and reason. Dr. Lahee emphasized the need of more adequate preparation in English composition, because of the inability of many graduates to compose acceptable reports. SHERWIN F. KELLY pointed out that much time in university training, which ought to be devoted to technical subjects, was taken up with English courses. He emphasized that it is the part of the universities to demand of the high schools that the students they send to the university be properly trained to speak and write English. Prof. W. T. THOM protested against the crowding of high-school material into already overcrowded college curricula. C. E. DOBBIN, chairman of the Committee on Applications of Geology of the American Association of Petroleum Geologists, described briefly the work of his committee in publicizing geology, and said that it found a widespread popular interest in the subject but a lack of appreciation of its importance. He recommended that attempts to coordinate the works of geologists and geophysicists be expanded somewhat, toward the further developing and encouraging of a "species of geopolitician" capable of assisting the progress of geology and geophysics by more vigorous advertising of

Jan 1, 1941

By B. S. Lement

No appreciable stabilization of the austenite-martensite reaction occurs in a 15 pct Cr-0.7 pct C steel unless some martensite is initially present. Stabilization is induced by interrupting the subcool below M,; however, disappearance of the stabilization effect as manifest by burst formation of martensite may occur on continued holding at the final subzero reaction temperature. The higher the temperature of intermediate cycling after the initial subcool, the more permanent is the stabilization effect at the final reaction temperature. Appreciable conditioning of retained austenite occurs on reheating to about 500°C. These phenomena are explainable on the basis of the reaction-path theory. A RECENT investigation' carried out by the authors has shown that isothermal transformation of austenite to martensite definitely takes place in a 15 pct Cr-0.7 pct C steel and that appreciable amounts of martensite can form in this fashion. Investigations2-" arried out on other steels and iron alloys make it seem probable that isothermal formation of martensite is a phenomenon of fairly general occurrence. The reaction-path theory of Cohen, Machlin, and Paranjpe5,7 explains isothermal transformation on the basis of thermal activation of strain embryos which generate martensite plates with a velocity approaching that of sound. On the other hand, the nucleation and growth theory of Fisher, Hollo-mon, and Turnbull8 egards isothermal transformation as due to growth of athermally formed martensite nuclei. The experimental evidence obtained thus far favors the reaction-path theory in that the martensite reaction seems to be nu-cleation-controlled rather than growth-controlled. Stabilization is another phenomenon of importance with respect to the austenite-martensite reaction. According to the reaction-path theory, stabilization is a result of relaxation of strain embryos. It is postulated that strain embryos are present at the austenitizing temperature in the form of dislocations or lattice imperfections in the austenite which vary in the extent to which the lattice is displaced along the strain reaction path leading to martensite. On quenching from the austenitizing temperature, athermal martensite starts to form as soon as the M. is reached, because the activation energy of the transformation which decreases with decreasing temperature is lowered to below the level of the highest energy strain embryos. Martensite plates are generated during the cooling below M, from embryos possessing energies above the activation energy corresponding to the temperature at which the cooling is stopped. The distribution of lower energy embryos is changed because of the elastic and plastic strains produced in the remaining austenite as a result of the transformation. This effectively increases the number of strain embryos at all levels of energy below the activation energy and tends to stimulate further martensite formation either iso-thermally or on subsequent cooling. However, if the temperature at which the cooling is stopped is high enough for relaxation of strain embryos to occur, some degree of stabilization against further transformation may be induced. Whether stabilization will be observed on subsequent cooling will depend on the extent of decrease of activation energy with temperature. If the activation energy decreases sharply with temperature, it is possible that transformation will appear to continue with decrease in temperature in spite of the loss of embryos by relaxation. However, with a more gradual decrease in activation energy, stabilization will be manifest by no further transformation on cooling over a measurable temperature range until the

Jan 1, 1954

By David J. Mack, Dennis R. O’Boyle

The mechanical properties of three polycrystalline intermediale Phases that have the y bvass structure were measured in compression between 400° and 900°K. At the lower testing temperatures— termed Region I— no plaslic deformalion occurred prior to brittle fracture. A1 higher temperatuves— lermed Region III—the three phases deformted plaslically for all strain rules from 1.5 to 36.0 x 10-4 sec-1. The homologous temperature for the inilialion of plaslic flow increased in the same order as tile atomic size difference between atoms in each plmse (0.50Tmp for y AgZn, 0.62Tmp for y CuZn, and 0.76 Tmp for y CuCd). The increased flow resistance oj. y CuCd above 0.50Tmp is explaitzed in terms of the more random arrangement of copper and cadmiwn atoms on the laltice sites of&apos; the y bvass slrilctlire. Plaslic deformation of the three intevmiediate phases in the smooth plaslic flow region appears to be controlled by oacancy-induced dislocation climb. RESULTS are reported in this paper on the mechanical properties of three binary intermediate phases having the complex cubic y brass structure (D82, 143m) containing fifty-two atoms in the unit cell. The structure of the prototype y brass phase, y CuZn, was first analyzed by Bradley and Thewlis&apos; based on the X-ray work of Westgren and Phragmen.2 The y brass structure can be visualized as an arrangement of twenty-seven body centered cubes (3 by 3 by 3) into a unit cell containing fifty-four atoms. From this cell the center atom and the four corner atoms are removed and the remaining fifty-two atoms are slightly displaced, resulting in the y brass structure. Approximately thirty-five binary intermediate phases that have an electron to atom ratio of 21:13 have been reported to form the y brass structure. The three y brass intermediate phases selected for this study are formed from elements in groups IB and IIB of the first and second long period. Each compound exists over a composition range that includes the stoi-chiometric composition A5BB (Cu5Zn8, Ag5Zn8, Cu5Cd8). y CuZn (a0 = 9.944A) has solubility limits extending from 57 to 67 at. pct Zn at 500°C apd melts peritecti-cally at 834°C; y AgZn (a0 = 9.326A) has a solubility range from 58 to 63 at. pct Za and melts peritectically at 661°C. y CuCd (a, = 9.596A) melts congruently at 563°C and has a maximum range of solubility extending from 58 to 64 at. pct Cd. In order to minimize coring and microporosity during solidification, the composi- tion of the compounds that form peritectically (y CuZn and y AgZn) was chosen so that the temperature difference between the liquidus and the solidus is only a few degrees centigrade. In selecting y brass compounds for this study, phases were avoided that contained a transition element or that had an electron to atom ratio greater than 1.70. Hume-Rothery et a1.3 has observed that, when the electron to atom ratio of y brass intermediate phases exceeds 1.70, atoms begin to drop out of the unit cell to maintain a constant electron to unit cell ratio. EXPERIMENTAL PROCEDURE Each of the three intermediate phases was prepared from elements having a purity >99.999 pct. Only trace quantities of impurities (<0.0001 pct) were detected by spectrographic analysis of the four elements. A master alloy of each compound weighing approximately 130 g was prepared by melting the elements in evacuated sealed quartz tubes heated in an electric furnace. Specimens having the desired diameter for the mechanical property measurements were obtained by remelting the master alloy in a Vycor tube under argon and drawing specimens from the melt into 4-mm-diam quartz tubes. To obtain a smooth surface on specimens drawn from the melt, the inside of the quartz tube was coated with a thin layer of graphite formed by thermally decompositing acetone. All specimens were imbedded in sealing wax and cut to the proper length with a diamond-impregnated cut-off wheel. The individual specimens (4 mm diam by 8 mm long) were then sealed in evacuated Pyrex tubes and homogenized at 500°C for 72 hr. Chemical composition, variations over the length of the rod (10 cm long) were generally less than 0.2 pct and the analyzed composition differed from the desired composition by less than 0.5 pct.4 Metallographic evaluation of the specimens after homogenization showed no evidence of a second phase in any of the compounds. The average grain size of the specimens after homogenization was 1 to 2 mm. All mechanical property measurements were carried out in an argon atmosphere using a compression apparatus described previously.5 Prior to applying the load to the specimen, the test apparatus was evacuated, back-filled with argon, and heated to the test temperature for 20 min to establish thermal equilibrium. EXPERIMENTAL RESULTS Mechanical properties measured as a function of temperature and strain rate for each of the three y brass phases were similar. From room temperature to the ductile-to-brittle transition temperature, only elastic deformation was observed prior to fracture.

Jan 1, 1968

By M. D. Banus, M. B. Bever, A. K. Jena

The heals of formation at 78", 195, and 273°K of the ternary compound h3SbTe2 based on the elements and based on the binary compounds In Sb and [inTe have been measured. The heats of formation at these temperatlcres of the binary compounds In Sb and In Te based on the elements have also been determined. Heal contents and free energies of the three compounds have been calculated from 0° lo 80I)°K. The free energies of joyrrzalion, heats of formations, and entropies of formation at 298°K have also been calculated. The results shown that the tertnary compound is metastable with vespecl to InSh and ln Te below 696 °K. bul is slable above that temperature. The weaker bonding of results in a positice entropy of formation which with incrensirzg temperature makes increasing negative conlvihtclions to the free energy and above 696°K renders the compound slable. THE ternary compound In3SbTez occurring in the quasi-binary system In Sb- In Te&apos; forms on cooling at 829°K by a peritectic reaction.&apos; Observations at 673" and 573 K have shown that this ternary compound decomposes slowly into the binary compounds InSb and1n~e.l&apos;&apos; It has not been possible to analyze the metastable behavior of the ternary compound because up to the present time data on its thermodynamic properties have been lacking. Some information on the binary compounds, however, is available. The heat of formation of InTe at 273°K and its free energy at 673°K are kn~wn.~&apos;~ The heats of formation of InSb at 78", 273&apos;, 298", and 723°K have been measured5-&apos; and its heat capacity between approximately 12" and 300"Kg9l0 is also known. In the investigation reported here the heats of formation at 78% 195% and 273°K of the ternary compound In3SbTez have been measured. The heats of formation of the binary compounds InSb and InTe at these temperatures have been obtained by combining new calorimetric results with previously published data. The heat contents and free energies of the three compounds at various temperatures from 0" to 800°K have been calculated. Against the background of this information, the metastability of the ternary compound will be discussed. 1) EXPERIMENTAL 1.l) Preparation of Specimens. The materials used consisted of the elements indium, antimony, and tellurium, the binary compounds InSb and InTe, and the ternary compound In3SbTez. The elements, obtained from American Smelting and Refining Co., had a nominal purity of 99.999+ pct. The compound InSb was Cominco semiconductor grade; the compound InTe was prepared from the elements by melting under a vacuum of 10-h m Hg followed by slow cooling. Three batches of specimens of the compound In3SbTez were used. One batch was prepared by melting appropriate amounts of the elements in an evacuated and sealed Vycor tube. The melt was held at approximately 100°K above the liquidus for about 8 hr, shaken repeatedly, and quenched into a mixture of ice and water. The specimen was annealed in vacuum at 760°K for 4 weeks. In preparing a second batch, a mixture of the component elements was melted and quenched in water. The resulting ingot was powdered. The powder was pressed into pellets, which were annealed in vacuum at 748" to 773°K for 4 weeks. A third batch was prepared in the same manner as the second, except that the starting materials were InSb and InTe rather than the elements. Metallographic examination of samples of the three batches and X-ray diffraction examination of a sample of the second batch did not reveal evidence of microsegregation or a second phase. The results obtained with the three batches showed no systematic differences. 1.2) Calorimetry. The calorimetric method has been described in detail." Samples of the compound In3SbTez, mechanical mixtures of InSb and InTe in the proportion of 1:2, and mechanical mixtures of indium, antimony, and tellurium in the proportion of 3:1:2 were added to a bismuth-rich bath at 623°K in a metal-solution calorimeter. These additions were made from 78°K (liquid nitrogen), 195°K (dry ice and acetone), and 273°K (ice and water). The heat effects of the additions were measured. The difference in the heat effects of the additions of a compound and the additions of the mixtures of its constituents, adjusted for differences in the concentration of the bath, is the heat of formation of the compound. In the concentration range not exceeding 1.5 at. pct solute, the heat effect of the additions was a linear function of concentration. The heat of formation refers to the temperature from which the additions were made, namely, 78", 195", or 273°K. Several calibrating additions were made in each calorimetric run. The calculated heat capacity of the calorimeter and hence the calculated heat effects of the additions of samples depend upon the values adopted for the heat contents of the calibrating substance. In this investigation bismuth at 273°K was used and a value of 4.96 kcal per g-atom was taken for (HGZ3"k . 2) RESULTS AND DISCUSSION 2.l) Heats of Formation. The heats of formation of the ternary compound In~SbTez from the component elements indium, antimony, and tellurium and from

Jan 1, 1968

Abrahamson. Guy C., (S&apos;43) Univ. of California, Berkeley. Calif. &apos; Abrego, Alfredo, (S&apos;43) Texas College of Mines Metallurgy, El Paso, Texas. Adamec, Lew, (S&apos;42) c/o Braden Copper Co., Ran¬cagua, Chile. Adams, Charles E., (S&apos;42) Box 1527, Stockton, Calif. Adams, John W? (S&apos;42) Asst. Petr. Engr., Vander¬ bilt Dist., Magnolia Pets. Co., Edna. Texas. Adams, Karl S., (S&apos;43) Univ. of New Ha mpshire, Durham; N. H. Adamson, Charles R., (S&apos;41) Univ. of Utah, Salt Lake City, Utah. Aguilar, Ruperto G., (S&apos;43) Texas College of Mines, El Paso,. Texas. Almone, Francis M., (S&apos;41) Univ. of Toronto, Toronto, Ont., Canada. Ainge, Ronald Farra, (S&apos;43) Otago University, Dunedin, New Zealand. Akarun, Cevdet A., (S&apos;44) Pennsylvania State College, State College. Pa.

Jan 1, 1944

By H. [Eyring], B. J. Zwolinski

[ ] The authors are to be commended for their excellent work on the activities of components in the solid state. It is, however, felt that certain points require clarification with reference to diffusion in the solid state. It is a well established point that any rate process in a non-ideal system can be expressed by the general equation [ ] where ko is the specific rate in an ideal system, and ?A, ?B ... , the activity coefficients of the reactants and ?± and ?M,?N the activity coefficient of the activated complex and the intermediates, respectively. With reference to diffusion, the following simplified treatment in correcting for non-ideality is proposed. The same free energy change is involved in moving a particle from a solution of one activity to a solution of another activity,

Jan 1, 1947

By PHILIP N. MOORE

PHILIP NORTH MOORE was born on July 8, 1849, at Connersville, Ind. His father, a civil engineer, was descended from Henry Moore who came from Ireland in 1773 to live in Washington, Pa. Through his mother, Philip Moore was descended from John North, who came to America in 1635 and settled in Connecticut. The story of Mr. Moore&apos;s life as told by himself is given on pages 373-386 of T. A. Rickard&apos;s "Interviews with Mining Engineers." He studied at Miami University, where he gained the degree of A.B. in 1870, and A.M. in 1873. In 1920 his alma muter conferred on him the honorary degree of LL.D. He, as a special student, was a member of the class of 1872 at the School of Mines of Columbia University.

Jan 1, 1930

NEW MEMBERS The following list comprises the names of those persons who became members during the period of Apr. 10, 1918, to May 10, 1918. BALLARD, JOHN I Supt., Cable Mining Corpn., Cable, Mont. BURKMAN, JOHN M. F., Constr. Engr., U. S. Smelt. Refin. & Min. Co., Care -University Club, Mexico City, D. F. CALLEN, ALFRED COPELAND, Head, Mining Engineering Dept., West Virginia University Morgantown, W. Va. CHADWICK, LAWRENCE, Chem., Mt. Elliott Copper Co., Ltd., Selwyn, via Townsville, North Queensland, Australia. CODY, FRANK W., Skimmer, Reverberatory Furnace, Arizona Copper Co., Clifton, Ariz. COOLBAUGH, MELVILLE F., Prof. of Chem., Colorado School of Mines, Golden, Colo. DODGE, ALLAN WAYNE The Dodge Agency, 104 East Iron Ave., Salina, bans. DONNELLY, LEONARD G., Pet. Geol., Sinclair Oil & Gas Co., Sinclair Bldg., Tulsa, Okla.

Jan 6, 1918

By AIME AIME

PRODUCTION of nickel in Cuba, a new source of this metal, has been started by the Nicaro Nickel Co., subsidiary of the Freeport Sulphur Co. Construction of the Nicaro plant in Oriente Province, Cuba, and of a refinery at Wilmington, Del., has been "substantially completed," according to Langbourne M. Williams, Jr., president. The initial rate of output is less than capacity operation, which will be reached when "the customary problems incident to the commencement of full- scale production are eliminated." The plant in Cuba for the treatment of the extensive nickeliferous ores of that region, and the refinery, were built by Nicaro for the account of the Defense Plant Corp. construction has been under way for eighteen months. The plants, when operating at capacity, are expected to increase America&apos;s sup-

Jan 1, 1944

By James B. Cathcart

Marine phosphorite deposits occur in Braxil, in the Bambui Group of late Precambrian or Early Cambrian age. The phosphorite is laminated, isoclinally folded, and is composed of black, elongated apatite pellets and quartz grains cemented by quartz and muscovite. Abundant, narrow quartz veinlets cut through the .rock at right angles to the elongation direction of the pellets. The phosphorite is 0 to 80 m thick and contains 5 to 30 percent P2O5. The deposit is elongate towards the northeast, and the central, thickest, and richest part is bounded by faults. Measured reserves are about 250 million tons that average a bout 13 % P205. Preliminary testing indicates that grinding, scrubbing, and desliming will produce a material usable for fertilizer manufacture at a cost competitive with imported phosphate fertilizers.

Jan 1, 1979

By H. I. Smith

THE technical and safety press have devoted much space in support of or in opposition to the use of booster and auxiliary fans in coal mines. The Mine Safety Board of the U. S. Bureau of Mines has given the matter consideration, and the Mine Ventilation Committee of the A. I. M. E. is now seeking a discussion of the merits and demerits of such fans to guide it in formulating recommendations. In this paper, I will set up some principles on which I believe most engineers will agree and from which we may work toward a decision, though as to what that decision shall be there may be a difference in opinion. Before stating the points on which I believe. there is accord, I will distinguish between booster and auxiliary fans.

Jan 1, 1927

Elected Died 1895 ABBOTT, AI ATTHUR 1908 1882 ABBOTT, ARTHUR V 1906 1905 ABE, MASAYOSHI 1909 1903 ADAMS, CHARLES C. 1905 1906 ADAMS, JOHN C. 1913 1905 ADAMS, WILLAMS 1909 1903 ADAMS, W. EDWARDS 1910 1884 ADDY, MATTHEW 1896 1906 AFFLECK, WILLIAM A. 1911 1889 AKERS, WILLIAMS A. 1906 1905 ALABASTER, RUPPERT C. 1911 1899 ALBERGER, LOUIS R. 1911 1894 ALLEN R B 1896 1905 ALLEN, R. SCOTT 1906 1886 ALLISON, ROBERT 1916 1874 AMIOT, H. 1892 1886 AMSLER, CARL 1894 1898 ANDRSON, JOHN W 1905 1895 ÅNGSTROM, CARL 1901 1887 ARCHBALD, JAMES 1910 1900 ARLETT, GEORGE H 1906 1895 ARMSTRONG, JOHN F 1898 1905 ARNOLDS, LEO F. 1917 1882 ARNOLDS, HUGO 1886 1875 ASHBURNER, CHARLES A 1889 1872 ASIIBURNER, WILLIAM 1887 1883 ATKINS, C M , JR 1885

Jan 1, 1923

By AIME AIME

THE coal classification session* on Monday morning, Feb. 17, was opened by a paper by M. R. Campbell, entitled "Natural Groups of Coal and Allied Fuels," in which he pointed out, by means of graphical presentation of selected proximate analyses of coal, that coals can be classified on the basis of their moisture content. He proposes four groups of coal, brown coal, hydrobituminous, bituminous, and anthracite, each subdivided into two or three sub-groups. In a written discussion of this G. H. Cady, of the Illinois Geological Survey, showed that there is, in general, a progressive decrease in the moisture of Illinois coals from north to south, and that it would be very difficult to draw any arbitrary line dividing the coals of the State into two groups on the basis of moisture content.

Jan 1, 1930

By AIME AIME

THE complete list of papers for the meeting of the Petroleum Division that is to be held" at Tulsa,&apos; Thursday and Friday, Oct. 3 and 4,, with assignment to individual sessions is given below. THURSDAY MORNING First Session Well Spacing Theory of Well Spacing-By W. P. Haseman. Discussion by S. C. Herold, J. R. Suman and Lester C. Uren. Well Spacing in the Long Beach Field, California-By - Stender Sweeney. Discussion by C. H. McNeese; R. R Brandenthaler and W. V. Vietti. Well Spacing in the Bradford Field, Pennsylvania-By Paul D. Torrey. Discussion by A. F. Melcher, R. M.. Haskell, J. B. Umpleby and J. B. Newby. Results of Different Well Spacing in the Salt Creek Field, Wyoming-By Fred E. Wood. Discussion by Sam Grinsfelder and Kenneth B. Knowles.

Jan 1, 1929

By Young C. Kim

Abstract-The use of computer models to design the ultimate open pit limits during feasibility studies as well as during long-range mine planning is becoming an enforced Practice in all types of mining, e.g., ferrous, non-ferrous, and coal. As a result, the state of the art in computerized ultimate pit limit design methodologies and associated computing and optimizing techniques has advanced considerably in recent years. Unfortunately, very little has been published to date regarding the preferred ultimate pit limit design philosophy, i.e., optimizing m satisfying, or regarding the modeling approaches being used for different types of orebodies. This paper reviews the current state of the art in various modeling approaches and optimizing techniques that are in use for different types of deposits, through available literatures and personal communications.

Jan 10, 1978

CLARENCE M. HAIGHT, Franklin, N., J. (communication to the Secretary*).-In that hart of Mr. Wilson&apos;s paper describing the Gilman cut-and-fill system, a few features do not appear to be fully explained. In what way is the waste used for filling obtained? The text mentions that, if waste is encountered when driving the filling raises, these raises are stopped until the fill is needed; that seems to suggest mining the capping for fill, which might make the backs of the stopes had as the stopes approach the top of the ore. If, on the other hand, the fill is brought to the raises in cars, are the crosscuts that are necessary in ore or waste? Is the cost of this fill included in the stoping costs given?

Jan 5, 1917

NEW YORK SECTION J. E. JOHNSON, JR., Chairman EDGAR RICKARD, Vice Chairman D. M. LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BOHN, Treasurer JOHN V. N. DORR LEWIS W.. FRANCIS The following minute was unanimously passed at a meeting of the NEW YORK SECTION AMERICAN INSTITUTE OF MINING ENGINEERS held on the evening of June 6, 1917, two regular meetings having been adjourned by unanimous consent until this date out of respect to the memory of the late Chairman of the Section. Minute The death of our beloved fellow member DR. DAVID H. BROWNE one of the foremost metallurgists and one of the most brilliant and original thinkers in the profession of mining engineers, the chairman for the past two years of this section, has caused throughout a wide circle of

Jan 9, 1917