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By J. M. Morkowitr

A. Sawatzky (Atomic Energy of Canada, Ltd.)—The detailed criticism by Markowitz of my simple treatment of the thermal diffusion of hydrogen in Zircaloy-2 indicates that my paper was not as lucidly written as it could have been. I would therefore like to reiterate several of the main points of my proposed mechanism and describe in more detail some of the features only implied in the original paper. The distribution equation derived in my paper was stated to hold only for the case where the volume taken up by the hydride was small compared to the volume taken up by the solid solution phase, subsequent work, mentioned below, having shown it to be out by only a few percent up to a hydrogen concentration of about 3000 ppm. Of course, hydrogen in the two-phase region alone is not conserved in my treatment as pointed out by Markowitz. On the contrary, one of the important features of my proposed mechanism is that in the presence of a temperature gradient a two-phase region cannot exist over the whole specimen. For example, if the specimen is entirely a + 6 initially, then on application of a temperature gradient, a single phase (a) region at the hot surface develops from time t = 0 onwards. As mentioned in my original paper, the interface between the a and a+d regions moves toward the colder surface of the specimen with a discontinuity in hydrogen concen- tration developing at the interface and increasing with time. This interface moves at such a rate that hydrogen in the specimen as a whole is conserved. It must be pointed out that my distribution equation (Eq. [5] in Markowitz's paper) holds only for linear geometry. It is easy to show that for the cylindrical geometry of Markowitz the assumptions used in my treatment lead to

Jan 1, 1962

By E. T. Turkdogan, J. H. Swisher

The solubility of oxygen in zone-refined iron was determined in the temperature range.from 881" to 1350°C. The solubility in a iron at 881°C ms found to be about 2 to 3 ppm; in y iron, the solubility was found to increase from about 2 to 3 ppm at 950°C to about 25 ppm at 1350°C. The permeability of oxygen in an iron -0.1 pct Al alloy was determined in the y iron range, using an internal oxidation technique. By combining the permeability and solubility data, the diffzisivity of oxygen in y and a iron was calculated. The oxygen diffusivity in solid iron may be s~immarized as follows: 8820 For 6 iron and IN a recent paper, Hepworth, Smith, and Turkdogan1 reported on the solubility, permeability, and diffusivity of oxygen in 6 iron, together with permeability data for oxygen in a iron. In the present investigation, similar measurements were made in the ? phase region. In addition, a solubility measurement was performed in the a phase region to permit calculation of the diffusivity of oxygen in a, iron. References to early work on this subject are given in the previous publication.' EXPERIMENTAL Solubility Measurements. The oxygen solubility was determined by equilibrating cylindrical samples 0.3 in. diam by 14 in. long of zone-refined iron in water vapor-hydrogen gas mixtures. The zone-refined iron was prepared by B. F. Oliver of this laboratory, using an apparatus and technique described elsewhere.2'3 Six zone-melting passes were used to achieve a total impurity level of about 30 ppm. Of this 30 ppm, the combined nickel and cobalt content was about 20 ppm, oxygen was 4 ppm, and all oxidizable impurities less than 1 pprn each. A vertical resistance furnace wound with molybdenum wire was used for the experiments. The temperature was measured before and after each experiment with a Pt/Pt-10 pct Rh thermocouple. In the gas train, flow rates of hydrogen and argon were measured with capillary flow meters, and the resulting mixtures were passed through a column containing 90 pct oxalic acid dihydrate and 10 pct anhydrous oxalic acid to obtain predetermined ratios of H2O to H2. The vapor pressure of H2O above this mixture as a function of temperature is well-known.4 The exit gas was ana- lyzed periodically for H2O, and good agreement (+3 pct) with the calculated composition was obtained. The zone-refined iron specimens were held in the furnace for a sufficient length of time for equilibration, e.g., 18 hr at 1350°C and 1 week at 881°C, then quenched in a brine solution. After removing the surface oxide from the samples by machining, duplicate analyses were obtained by a combined vacuum fusion-infrared method; oxygen analysis was reproducible within 2 ppm. Permeability Measurements. The permeability of oxygen in alloys containing about 0.1 pct A1 was determined by internal oxidation and measurement of the subscale thickness as a function of time. The experimental alloys were prepared by adding aluminum to electrolytic iron (grade 104A plastiron) that had previously been vacuum-carbon deoxidized. The resulting ingots contained about 20 ppm O, 100 pprn C, 40 pprn Si, 50 ppm Mo, 20 ppm P, 20 ppm S, and 20 pprn Zr as the principal impurities. After hot rolling the ingots to 1-in.-thick slabs, specimens were machined from the stock in the form of rectangular plates, 4 by 5 by 2 in. The general procedure for the permeability experiments was the same as those for the solubility measurements. The specimens were cooled in a reducing atmosphere rather than quenched, however, in order to maintain a clean surface for measurement of the sub-scale thickness. This measurement was made on a polished cross section of each specimen, using a microscope with a micrometer stage. The inclusions formed at the lowest temperature 1033°C were too small to be seen with an optical microscope. An electron micrograph showing the size and shape of individual particles is shown in Fig. 1. The dark band in the picture is a boundary between two subgrains. The subscale thickness in these samples was measured with an optical microscope after heavily etching in 2 pct nital, which gave contrast between the subscale and the unoxidized zone.

Jan 1, 1968

By S. H. Ward

Since the advent of the first airborne electromagnetic system, it has been evident that such systems were inherently limited to shallow depths of exploration of the orderof 100 to 200 feet. Hence in 1948 the author and his associates commenced a study of the feasibility of applying natural audio frequency magnetic fields to investigation of the electrical properties of the subsurface in order to provide a system capable of overcoming this limitation. This research culminated, in the summer of 1958, in the development of a new airborne prospecting device — AFMAG. This device has detected surface massive sulphide bodies while flown at heights as great as 3000 feet. Hence, by inference, it is deduced that it could find similar sulphide bodies if they were buried 2500 feet below surface and the aircraft flown at 500 feet. Thus a considerable improvement over conventional airborne electro-magnetic systems is obtainable with AFMAG. Airborne exploration in mountainous terrain involving deep valley fill now becomes possible. Examples are presented of the results of actual airborne AFMAG test surveys over known deposits of massive sulphide mineralization. Interpretation of the data is discussed with particular reference to the knowledge of size, dip, depth, depth extent, and conductivity of causative bodies as deduced from the flight records. The possibility of mapping major geologic structures, for both mining and oil exploration purposes, is discussed with the aid of examples of airborne AFMAG data. INTRODUCTION Electrical prospecting with natural audio frequency electromagnetic waves as a source has, within the last three years, become a practical reality. Both airborne and ground survey instruments under the trademark "AFMAG" (for audio frequency magnetics) have been used successfully in the search for conductive mineral deposits. It is the object of this paper to discuss the principles of airborne AFMAG and to illustrate its application by means of examples obtained over known geological situations. WHY AFMAG? In view of the large number of good airborne electromagnetic systems available for purchase or contract surveying, one may well ask, "Why another new system?". Primarily the answer lies in the fact that AFMAG does not suffer from the very limited depth of exploration available with, and inherent in, any conventional airborne electromagnetic system. AFMAG is not conventional insofar as an artificial transmitter is not required. Only a receiving and detecting device is employed. The electromagnetic fields measured are those from millions of electrical discharges in the atmosphere (e.g;..- lightning strokes). Their random distribution in time and space make these fields difficult to employ and it is only with recent advances in the electronics of geophysical instrumentation that this has become possible. A second reason for AFMAG and one of its

Jan 1, 1961

By AIME AIME

EARLE EDWARD SCHUMACHER, the new Chairman of the Institute of Metal, Division. is well known to the metallurgical profession. His election a, Chairman is the culmination of fifteen years' service to the Institute, beginning in 1930 when he was elected Member. Since that time he has served as member of the I.M.D. Data Sheet Committee. 1935-40; Papers and Publication Committee. 1936; Executive Committee. 1937-1910: Papers and Programs Committee, 1937-1938. (Vice-Chairman, 1939-40, Chairman. 1941-12): Annual Award Committee. 194142. (Vice-Chairman, 19431: Vice-Chairman, LM.D., 1943-44; Chairman Publication Committee, 1943-44; member Powder Metallurgy Committee), 1944. Pew other men have contributed so Much time anti effort in so many way- to the interests of the metals branch o4 the A.I.M.E.

Jan 1, 1945

By Arnulf Muan, Klaus Schwerdtfeger

Equilibrium ratios C02/C0 of a gas phase coexisting with selected phase assemblages of the system Fe-Mn-0 have been determined in the temperature range 1000" to 1300°C. The oxygen pressure for the "hfnO" +hfn30, equilibrium and for the "(Fe,hTn)O" + (Fe,Mnh 0* equilibrium at high manganese contents has been determined by electromotive force measurements using stabilized zirconia as a solid electrolyte. The notstoichometry 01' "hTnO" and of "(Fe, iM1z)O" solid solutions has been determined by ther-mog-/avi?netry and by wet-chemical analysis. The data obtained are used to derive activity-composition relations in "(Fe,hfn)O" and (Fe,Mn),O4 solid solutions. WUSTITE "FeO" and manganosite "MnO" form a continuous series of solid solution at high temperatures,' and so do magnetite Fe304 and the high-temperature, cubic modification of Mn304 (Ref. 2) (high hausmannite, -1170). The oxides "FeO" and "MnO" are cation-deficient phases.495 The nonstoi-chiometry of "(Fe,Mn)O" solid solutions has been studied by Engell and ~ohl' at two selected C02/C0 ratios at 1250°C. The two oxide end members of the spinel solid solution, FesO4 and Mn,04, however, are known to be close to stoichiometric under the experimental conditions used in the present investigation.''' The oxygen pressures of "(Fe,Mn)07' solid solutions in equilibrium with iron have been determined by Schenck and coworkers,8 by Foster and welch," and by ~n~e1l.l' The two former groups equilibrated the condensed phases in C02-CO atmospheres of lmown compositions, whereas Engell" used a galvanic cell with stabilized zirconia as a solid electrolyte. The results of these investigators are not in good agreement. Activities of FeO in manganowiistite as calculated from the results of Foster and Welch show ideal behavior, those of Engell yield a pronounced positive deviation, and those of Schenck et 01. show a moderate positive deviation from ideality. In the present work oxygen pressures for the iron + manganowiistite and manganowustite + spinel equilibria and the nonstoichiometry of manganowiistites have been measured. The data were used to calculate activities in the manganowiistite and spinel solid solutions. EXPERIMENTAL METHODS The COz/CO ratios at which manganowustite and iron are in equilibrium were determined by thermo-gravimetric and quenching methods. Experimental details are described in a previous publication.'2 In the thermogravimetric technique, incipient reduction of manganowiistite pellets to metallic iron was observed as a break in the weight vs log COZ/CO curve. In the quenching technique, manganowiistite samples were partially reduced to metallic iron, or the metallic iron of manganowustite + metallic iron mixtures was partially oxidized to manganowustite, in atmospheres of constant C02/CO ratios. After quenching the composition of the oxide phase was determined by X-ray lattice parameter measurements and comparison with a standard curve obtained from oxide solid solutions of known compositions. The nonstoichiometry of "MnO" and "(Fe,Mn)07' solid solutions was determined by chemical analysis of samples equilibrated in C02-CO atmospheres and quenched to room temperature, as well as thermo-gravimetrically by reducing (Fe,Mn),04 or Mn304 to manganowiistite or manganosite. The equilibrium between manganowiistite and (Fe,Mn),04 was measured thermogravimetrically by reducing (Fe,Mn),04 solid solutions having composition in the range of %„ l(NFe +NM) from 0 to 0.63. No experiments could be performed with this technique at higher manganese contents, because the equilibrium C02/C0 ratios are too large for accurate control. An additional difficulty arises at the higher manganese contents due to the strong increase in oxygen content of the manganowustite phase with increasing log Py near the manganowiistite-spinel boundary. Consequently a sharp break in the weight loss vs log C02/CO curve cannot be observed at the phase boundary. At high manganese contents of the manganowiistite, e.g., (NMn/(NF~ + NMn) > 0.9, electromotive force measurements with stabilized zirconia as a solid electrolyte were made to determine the equilibrium oxygen partial pressure. Experimental details are described in a previous paper.* Mixtures of "(Fe,Mn)O" and (Fe,Mn),04 were pressed to pellets, and the oxygen pressure of the equilibrated samples was compared to that of Ni + NiO mixtures in the cell The composition of the manganowiistite in the equilibrated two-phase mixture was determined by lattice parameter measurements and comparison with known standards. The oxygen pressure for the Ni + NiO equilibrium was taken from available data.l3~l4 No reliable results were obtained with the electromotive force technique on iron-rich oxides. The electromotive force drifted strongly with time in this composition range. An additional difficulty arises from the partial de-

Jan 1, 1968

AT A MEETING of the Shareholders of the Russo-Asiatic Cons. Ltd., in London, Oct. 23, 1922, LESLIE URQUHART, chairman of the com- pany made the following statement:* I come now to our recent negotiations with the Soviet Government and to the agreement which has resulted from them. You will remember that the conference at The Hague broke up without having achieved anything very definite. It was not, however, a failure. It elicited from M. Litvinoff an offer which will, I think, come to be regarded as a milestone in the progress of Russia from a ruinous and unpracticable Communism towards a modified form of capitalism. The offer made by M. Litvinoff at The Hague amounted in effect to this: that in return for political recognition on our part the Soviet Government would first acknowl-edge its liability for Russia's national foreign debts, and, secondly, would give the original foreign owners of property in Russia effective compensation. A very great advance that. It showed-and there have been many other signs to confirm it-how real and persistent has been the internal evolution of Russia during the past year from Marxism to the economics of the Western world. I will not now detain you with the reasons why M. Litvinoff's highly promising and significant offer came to nothing. The fact that it had been made and the further fact that The Hague Conference had separated indefinitely were the important things. The first fact seemed to indicate that the Soviet rulers, after all, proved to be people with whom one could do business. The second fact rather emphatically showed that the way to do business with them was not by unwieldy poly-glot conferences of ministers, officials and experts representing a few dozen different governments and a few dozen different sets of national interests. That method had been tried at Genoa. It was tried again at The Hague. Each time it failed, and having failed it left the road clear for a simpler and more direct approach.

Jan 12, 1922

By L. J. Health

Synthetic rock with predictable porosity and permeability has been Prepared from mixtures of sand, cement and water. Three series of mixes were investigated primarily for the relation between porosity and permeability for certain grain sizes and proportions. Synthetic rock prepared of 65 per cent large grains, 27 per cent small grains and 8 per cent Portland cement, gave measurable results ranging in porosity from 22.5 to 40 per cent and in permeability from 0.1 darcies to 6 darcies. This variation in porosity and permeability was caused by varying the amount of blending water. Drainage-cycle relative permeability characteristics of the synthetic rock were similar to those of natural reservoir rock. INTRODUCTION The fundamental behavior characteristics of fluids flowing through porous media have been described in the literature. Practical application of these flow characteristics to field conditions is too complicated except where assumptions are overly simplified. The use of dimensionally scaled models to simulate oil reservoirs has been described in the literature. 1-3 These and other papers have presented the theoretical and experimental justification for model design. Others have presented elements of model construction and their operation. In most investigations the porous media have consisted of either u ncon soli da ted sand, glass beads, broken glass or plastic-impregnated granular substances—materials in which the flow behavior is not identical to that in natural reservoir rock. The relative permeability curves for unconsoli-dated sands differ from those for consolidated sandstone. The effect of saturation history on relative permeability measurements is discussed by Geffen, et a1.4 Wyga15 has shown quite conclusively that a process of artificial cementation can be used to render un consolidated packs into synthetic sandstones having properties similar to those of natural rock. Many theoretical and experimental studies have been made in attempts to determine the structure and properties of unconsolidated sand, the most notable being by Naar and Wygal.6 Others have theorized and experimented with the fundamental characteristics of reservoir rocks. This study was conducted to determine if some general relationship could be established between the size of sand grains and the porosity and permeability in consolidated binary packs. This paper presents the results obtained by changing some of the factors which affect the porosity and permeability of synthetically prepared sandstone. In addition, drainage relative permeability curves are presented. EXPERIMENTAL PROCEDURE Mixtures of Portland cement with water and aggregate generally are designed to have certain characteristics, but essentially all are planned to be impervious to water or other liquids. Synthetic sandstone simulating oil reservoir rock, however, must be designed to have a given permeability (sometimes several darcies), a porosity which is primarily the effective porosity but quantitatively similar to natural rock, and other characteristics comparable to reservoir rock, such as wettability, pore geometry, tortuosity, etc. Unconsolidated ternary mixtures of spheres gave both a theoretically computed and an experimentally observed minimum porosity of about 25 per cent.7 By using a particle-distribution system, one-size particle packs had reproducible porosities in the reproducible range of 35 to 37 per cent.6 For model reservoir studies of the prototype system, a synthetic rock having a porosity of 25 per cent or less and a permeability of 2 darcies was required. The rock had to be uniform and competent enough to handle. Synthetic sandstone cores were prepared utilizing the technique developed by Wygal.5 Some slight variations in the procedure were incorporated. The sand was sieved through U. S. Standard sieves. A 18-20 sand denotes that the sand passed the Number

Jan 1, 1966

By B. E. Warren

Jan 1, 1965

By Horace V. Winchell

This paper, embodying information acquired by the writer in his work in connection with the Geological Survey of Minnesota, is presented by permission of the State Geologist. Historical.—On November 16, 1890, the workmen of Captain J. A. Nichols, of Duluth, Minn., encountered in a test-pit on the northwest quarter of section 3, township 58, range 18, west of the fourth principal meridian, the body of soft ore now called the Mountain Iron mine. Hard ore, chiefly magnetic, had been known for many years on the Mesabi range, and explorations made by Mr. E. W. Griffin, of Minneapolis, near the falls of Prairie river in T. 56-24 and T. 56-25, and by John Mallmann, at the Mallmann explorations, T. 59-14, had revealed some hard hematite interbedded with quartzite and low-grade soft ore; but this was the first discovery of merchantable hematite on the range. Captain Nichols had been exploring more or less along the range for some two years. To him and to the Merritt brothers, of Duluth and Oneota, who, unshaken in Faith by the discouraging reports of explorers, miners, experts, and geologists, had persevered in the search for ore, great credit is due for the final success, and large rewards have accrued to them already.

Jan 1, 1893

By Andrew Mayer

Early in 1942 National Lead Co. was requested by the War Production Board to construct and operate a plant for the Government to produce magnesium by the ferrosilicon process which had been developed by Dr. E. M. Pidgeon in the laboratories of the Canadian National Research Council. A contract with the Defense PlantCorporation was concluded in May 1942 and Magnesium Reduction Co., a wholly owned subsidiary of National Lead Co., was formed to carry out this project. The capacity of the plant was rated at I0,000,000 lb. of magnesium per year, equivalent to an average production of about 14 tons per day. The Process The process, in brief, is as follows: The raw materials are dolomite and ferro-silicon, 75 per cent grade. The dolomite is calcined, the calcine and ferrosilicon are ground and mixed and the mixture is briquetted. The briquets are charged into tubular retorts of chrome-nickel steel set horizontally in a furnace with the open ends projecting outside the front wall. The retorts are then closed and evacuated. Magnesium is liberated according to then reaction 2(MgOl CaO) + Si = 2Mg + zCaO, Si% It is distilled from the charge and con- densed on a removable sleeve in the throat of the retort. Sodium and potassium, if present, are also liberated, distilled and condensed on a "sodium condenser" in the end of the retort. At the expiration of the distillation period the retorts are discharged and the cycle of operations is repeated. For the rated daily capacity of 14 tons of magnesium there are required approximately 170 tons of dolomite, equivalent to about 85 tons of calcine, and 16.5 tons of ferrosilicon. The retort residue, a bulky powder which at present is waste, amounts to about 87 tons. Choosing the Site The investigation to select the location of the plant was conducted by the Research Laboratories of National Lead Co. This work included geologic and economic surveys of a number of districts, examination of dolomite samples by chemical, spectrographic and petrographic methods and large-scale tests of dolomite from several of the more promising localities. in the last-named tests 2-ton samples were put through the ferrosilicon process in the pilot plant of the Canadian National Research Council, under the guidance of Dr. Pidgeon. The conclusions drawn from the investigation, in regard to the quality of dolomite to be used in the ferrosilicon process, were: First, the dolomite should contain not less than 21 per cent MgO and not more than 2 per cent acid-insoluble material. Second, the dolomite should

Jan 1, 1944

Gach-Saran.—The most important development of 1937 has been the successful completion of initial exploratory wells in the Gach Saran (formerly known as Gach-i-Qaraghuli) field, about 125 miles southeast of Haft Kel. Two of these wells are rated at 33,000 bbl. per day at flowing pressures exceeding 800 lb. Drilling is proceeding with the object of delimiting the structure. Exploratory drilling is also being undertaken in several areas within the company's concession. In the producing fields the policy of controlled production has been maintained as in the past, and drilling has been limited to that required for maintenance of production and general control of the fields. Acid treatment to increase production when desired has continued to be successful in most cases. Table 1.—Crude Production in Iran Masjid-i-Sulaimana Haft Kel Total Year barrelsb Ton Barrelsb To Barrelab 1936 3,641,247 27,820,000 4,473,849 34,200,000 8,115,096 62,020,000 193P 4,375,112 33,110,000 5,693,849 43,480,000 10,068,961 76,590,000 * Net production; i.e., excluding surplus products re-injected to reservoir. 6 To nearest 10,000. " Correct to November, with an added estimated figure for December. Masjid-i-Su1aiman.—There have been no new developments in this field. The policy of returning, as and when necessary, surplus products to the reservoir has been maintained. Haft Ke1.—Drilling to explore deeper formations has been undertaken, but has not progressed far enough for conclusive results to be drawn. Gasoline retention in the crude by means of multistage pressure stabilization has been continued as in past years. Separation pressures are as follows: well-head separators, 500 lb.; central battery, 190, 85, 40, 20 and 10 lb. per sq. in., respectively. The stabilized crude is delivered to pipe line at atmospheric pressure, or ex the 10-lb. stage, in accordance with refinery requirements.

Jan 1, 1938

By Louis J. Demer, Paul A. Beck

As reported in a previous publication,1 isothermal grain growth in high purity aluminum and in an aluminum alloy with 2 pct magnesium can be adequately described by means of the empirical relation: [ ] or in some cases, by the simpler relation, [ ] Here, D is the average grain size after an annealing period t. The annealing period includes the time for complete recrystallization R, and the time for grain growth [to]. DA is the grain size as recrystallized, n is a parameter depending on the temperature and on the material. The effect of 2 pct magnesium in solid solution was to decrease D, and to increase R, A and n at a given temperature. The present work was undertaken in order to investigate the above listed effects of magnesium in solid solution, as functions of the magnesium content. The work also includes the study of certain anomalous effects observed in the recrystallization and grain growth of the 2 pct magnesium alloy at 350°C. EXPERIMENTAL PROCEDURE The method of producing the ingots used in this work was described in detail1 and need not be reproduced here. The materials used were high purity aluminum, furnished by the Aluminum Co. of America, of lot analysis shown in Table I and magnesium from a high purity distilled stock of magnesium crystals. [ ] Ingots were prepared for a series of binary aluminum-magnesium alloys of increasing alloy content. The numbers used to designate these ingots and their magnesium contents by chemical analysis are given in Table 2. [ ] The analyses showed no difference in composition between the top and the bottom of the ingots. Spectrographic analysis of the ingots for elements other than magnesium showed, within the limits of accuracy of the method, no increase in impurities over the amounts given in the lot analysis for the high purity aluminum in Table I. Careful microscopic study of ingot 21 in the as-cast condition, at magnifications up t0 1500X, revealed a cer-

Jan 1, 1948

By W. A. Backofen, N. E. Paton

DEFORMATION twinning contributes to the plasticity of titanium and has been reported on {10i2}, {1121},{11221}, {1123}, and {1124} planes.' Twinning on {1011} has also been reported in commercially pure titanium as a result of quenching from 1000', but no reports of such twins occurring as a result of deformation alone are known to the authors. In this study single crystals grown from iodide titanium were compressed parallel to the c axis over the temperature range 25 to 800°C. From it has come evidence that (10il) deformation twins are the most common type between 400" and 800°C. Crystals about 6 mm high with a rectangular cross section measuring about 3 by 4 mm were used in the tests. Chemical analyses showed them to contain 220 to 250 ppm 0 arid 10 to 15 ppm N. The long axes of the crystals were made parallel to the c axis while the sides were parallel to (i100) and (1120), as shown in Fig. 1. The crystals were compressed between polished alumina platens with no lubrication, in a vacuum of 2 x lom5 torr. Between 25' and 300°C the predominant twinning mode was (11221, which is to be expected for this stress state. There was an abrupt change at 400°C, however, and from that temperature up to 800°C twinning took place almost entirely on (10i1 ). Twin planes were determined by the two-surface rnethd. Measurement of the crystal orientation within several (10i1) twins by means of polarized-light4 and transmission electron microscopy showed that the lattice reorientations were the same as those previously reported for the (10i l ) twinning in magnesium.' This reorientation is consistent with The calculated (10il ) twinning shear for titanium is 0.10, while that measured from surface offsets on a (1150) face, which is parallel to the shear direction, was about 0.15. Slip within the twins, or in the matrix adjacent to the twins, probably accounts for the larger measurement. Slip in both locations was judged to have occurred from observations on foils in the electron microscope.

Jan 1, 1970

By K. P. Gupta

In ternary systems containing silicon and transition elements, silicon was found to stabilize the a phase.1 At 1000°C a broad a-phase region was found in the Cr-Mn-Si system,1 which extends very close to the Mn-Si binary line (within about 3 at. pct Cr). Later investigation showed that, if chromium was replaced by small amounts (3 to 5 at. pct) of v,1 Ti, Nb, Ta, Mo, or w,1 the a phase or the R phase was again stabilized. Whether stabilization of complex crystal structures is possible by small additions of iron, cobalt, or nickel to Mn-Si is not known. Investigation of the Co-Mn-Si system4 shows the presence of several ternary phases, but at cobalt concentrations higher than 10 at. pct. In the present work the ternary systems Fe-Mn-Si and Co-Mn-Si were investigated at low iron and cobalt concentrations (< 7 at. pct Fe or Co) in search of phases of complex crystal structure. Experimental Procedure. The alloys were pre-pared by induction melting Co (99.8 pct), Si (99.9 pct), electrolytic Fe (99.88 pct), and Mn (99.9 pct) in recrystallized alumina crucibles under an inert atmosphere of argon gas. The alloy specimens were wrapped in molybdenum foil, sealed in argon-filled (at 1/2 atm) silica capsules and annealed for 72 hr at 1000" 1°C, and water-quenched. The use of argon-filled capsules was found to reduce the losses during annealing and the molybdenum foil prevented reaction of the manganese with silica. The total weight loss due to annealing and melting was found to be less than 1 pct for each alloy. The alloys were not analyzed chemically. A part of each annealed specimen was polished and examined metal-lographically using etching solutions, a) 0.1 to 0.5 pct oxalic acid solution in water, or b) 0.5 pct HNOs in methyl alcohol. Even though the etching solutions were quite dilute, the specimens were heavily etched and stained if the etching time exceeded more than 5 sec. Etching times found suitable were usually 1 to 3 sec. For X-ray diffraction work, a part of each annealed specimen was powdered by crushing after the exposed surface was ground off. X-ray diffraction patterns were taken with powder specimens using a 20-cm-diam asymmetrical focusing camera and Fe K radiation. These powder patterns were found quite satisfactory for the purpose of phase identification. However, X-ray diffraction patterns of single-phase alloy powder specimens were also taken using a Siemens diffractometer and filtered Cr-Ka radiation for greater resolution of the diffraction lines. Results and Discussion. In the Fe-Mn-Si system a new ternary phase was found at 1000°C between the p manganese and the MnsSi phase regions. The approximate phase relationships in this region of the 1000°C isothermal section are shown in Fig. 1. The new ternary phase, designated as the K phase, was found to occupy a narrow region about 1 at. pct in width and extending from Fee.oMn74.5Silg.5 to Fe.Mn.Silg.. At the high-iron content region, the K phase was found in equilibrium with the p manganese and the MnsSi phases but, at the low-iron content end of the K-phase region, the phases in equilibrium with the K phase were the p manganese phase, the MnsSi phase, and another new phase, designated in Fig. 1 as the v phase. The v

Jan 1, 1964

By D. A. Elgillani, M. C. Fuerstenau, J. D. Miller

Adsorption of lead and ferric iron on quartz and alumina is presented as a function of pH. Only the hydrolyzed species of these metal ions, FeOH++ and PbOH+, adsorb significantly on each of these minerals. Zeta potentials of quartz were measured as a function of pH in the presence of various additions of aluminum, lead, and magnesium salts. Sign reversal occurs at the pH values where significant concentrations of hydroxy complexes are formed. Models of adsorption are presented in the absence and presence of collector. The mechanism of adsorption of metal and collector species in the activation of nonmetallic minerals is still the center of considerable discussion in spite of the extensive study given this system. Until recently, the view was widely held that hydrated metal ions were responsible for this phenomenon. This fact is surprising, since it had been shown that the pH range in which flotation is effected corresponds to that in which metal ion hydrolysis occurs.&apos; Additional support of this concept was pro vided by the work of Wolstenholme and Schulman in another system.&apos; Later work has shown that hydroxy complexes of metal ions are the active species. These studies have also indicated that basic aqueous complexes of metal-collector may be necessary for flotation.3-7 Depending on the molecular weight of the collector, formation of these complexes may occur before or after precipitation of the metal-collector salt has occurred. Ion pair formation can occur when low molecular weight collectors are involved because relatively high concentrations of metal hydroxy complex and collector can be present in solution before precipitation occurs. This is not the case when high molecular weight collectors are used. A model of aqueous complex adsorption has been presented6,7 in which it has been assumed that adsorption occurs by the formation of water from adsorbed hydroxyl and hydrogen of the hydroxyl contained in the complex. Other authors8 have suggested that hy-droxy complexes are involved in these systems but that collector adsorption occurs by replacement of the hydroxyl of the adsorbed metal hydroxy complex with a fatty acid anion. All of these investigations have involved mineral surfaces that were negatively charged so that it is not possible to state with certainty whether hydrated metal ions or hydroxy complexes are the active species in this system. Use of a positively charged mineral should be helpful, however, since the hydrated metal ion will be repelled from this surface. On the other hand, if the hydroxy complex adsorbs by splitting out water, surface charge should have no effect because of the free energy decrease that the system will experience when water is formed. In this regard, sapphire is well-suited for study, since its surface is positively charged until approximately pH 9. Electrokinetic studies of quartz in the presence of various metal ions should also be useful in establishing the mechanisms of adsorption in these systems. That is, if the hydroxy complexes adsorb by water formation, drastic changes in the zeta potential should occur in the pH range in which hydrolysis occurs. In this view, adsorption of ions of widely different hydrolysis characteristics on both sapphire and quartz was measured. In addition, zeta potentials of quartz were measured as a function of pH in the presence of various metal ions and compared with flotation responses obtained under similar conditions. Experimental Materials and Techniques Reagent-grade aluminum, ferric and magnesium chlorides, and lead nitrate were used in this investigation. Adjustments in pH were made with reagent-grade HCl or KOH. Conductivity water, made by passing distilled water through an ion exchange column, was used in all of the experiments.

Jan 1, 1971

By William E. Ford, Edward Salisbury Dana

URANINITE. Cleveite. Broggerite. Nivenite. Pitchblende. Isometric. In octahedrons (o), also with dodecahedra1 faces (d) ; less often in cubes with o and d. Crystals rare. Usually massive and botryoidal; also in grains; structure sometimes columnar, or curved lamellar. Fracture conchoidal to uneven. Brittle. H. = 5&apos;5. G. = 9&apos;0 to 9&apos;7 of crystals; of massive altered forms from 6&apos;4 upwards. Luster submetallic, to greasy or pitch-like, and dull. Color grayish, greenish, brownish, velvet- black. Streak brownish black, grayish, olive-green, a little shining. Opaque. Comp. -A uranate of uranyl, lead, usually thorium (or zirconium), often the metals of the lanthanum and yttrium groups; also containing the gases nitrogen, helium and argon, in varying amounts up to 2&apos;6 p. c. Calcium and water (essential?) are present in small quantities; iron also, but only as an impurity. The relation between the bases varies widely and no definite for- mula can be given. Radium was first discovered in this mineral and it has been shown that it and the helium present are products of the breaking down of the uranium.

Jan 1, 1922

By G. Bruggeman, K. G. Kreider

Grain boundary dij]usion coefficienls were measured in tungsten between 1400° and 2200° C and can be expressed by the equation sq cm per sec This activation energy confirms some eavlier estimates made .from tungsten sintering experiments. Grain boundary diffusion was found to occur in sub-bozrndavies having -misorientations of less than 10 deg. The actiuation energy for this subboundavy diffusion is equal to that for dijjusion in incoherent grain boundaries with in the limits of error. This is shown to be consistent with the dislocation model of Low-angle boundaries wheve diffusion occlcvs along- the dislocation &apos;YPipes" comprising -tile boundary. RECENT investigations of the sintering of tungsten powders all report activation energies which are considerably less than the activation energy for tungsten volume diffusion. Kothari&apos; reports a value of 100 * 5 kcal per mole, Hayden and Brophy&apos; obtained 90 kcal per mole, and Vasilos and smith3 found 110.7 kcal per mole from their sintering studies. Since most determinations of the activation energy for volume diffu-sion4-&apos; fall between 120 and 160 kcal per mole (the true value seems most likely to be nearer 150 kcal per mole), the conclusion is drawn that the mass transport leading to densification during sintering is accomplished by grain boundary diffusion. This interpretation is consistent with various diffusion models of the sintering process. 10-12 Vasilos and Smith calculate diffusion coefficients from their data which fit the equation D * 1.36 x 10* exp(-llO,700/HD However, no direct measurements of tungsten grain boundary diffusion have been made. Furthermore, considerable disagreement exists between the directly measured values of tungsten volume diffusion.&apos;-&apos; In order to corroborate the inferred results of the sintering experiments concerning grain boundary diffusion and to provide accurate diffusion data essential to the analysis of the kinetics of creep, oxidation, precipitation, and so forth, the present work was undertaken to measure self-diffusion in single-crystal and polycrystalline tungsten between 1400" and 2200°C. It is within this temperature range that tungsten sintering is done, the re crystallization of tungsten occurs, and the widest application of tungsten as a high-temperature material will probably be made. EXPERIMENTAL PROCEDURE Radioactive WlE5 was produced by irradiating tungstic acid in a neutron flux of 1.2 x 1012 neutrons per sq cm per sec for 36 hr. A 2-week waiting period was allowed for the decay of w"~ also produced by the irradiation. (w"~ has a half-life of 24 hr.) The half-life of the remaining isotope was determined to be 75 days confirming the presence of w lE5 and the absence of any undesired radionuclide. Specimens 4 in. in diam and $ in. thick were cut from polycrystalline swaged tungsten rods (recrystal-lized) and from Linde single-crystal rods. Chemical analyses of these materials appear in Table I. Actually upon closer examination, the single-crystal specimens were found to consist of several subgrains separated primarily by tilt boundaries in which the misor-ientation ranged from 3 to 10 deg. Thus, it was possible to measure boundary diffusion coefficients in these low-angle subboundaries as well as in the incoherent boundaries of the polycrystalline specimens. The two faces of each specimen were ground flat and parallel within 0.0001 in. The radioactive tungstic acid was dissolved in concentrated ammonium hydroxide, placed on the ground flat of the specimen, and evaporated to dryness. The oxide was then reduced in hydrogen at 1000°C resulting in a layer of wlE5 approximately 1 p thick. The diffusion anneals were performed in vacuum in a tantalum resistance furnace. Time at temperature ranged from 10 hr at 1400°C to 2 hr at 2200°C. The penetration profile was determined by measuring the residual activity after successive removal of surface layers by grinding on metallographic polishing paper. Extreme care was exercised to insure that sections were always taken normal to the diffusion direction; this was verified repeatedly by checking that front and back surfaces of the specimen remained parallel. The activity was measured with an end-window Geiger-Mueller counter. The sides and edges of the specimen were well-shielded to eliminate possible effects due to surface diffusion. The weight of the

Jan 1, 1968

By Franklin Moeller

Discussion of the paper of FRANKLIN MOELLER, presented at the New York meeting, February, 1916, and printed in Bulletin No. 110, February, 1916, pp. 343 to 354. K. A. PAULY, Schenectady, N. Y.-I read with interest Mr. Moeller&apos;s paper descriptive of the mechanical parts of the new electric hoist at the Granite Shaft of the North Butte Mining Co. and as the paper treats largely of the mechanical equipment I have little discussion to offer. There is, however, one question which I would like to ask and that is, why the discrepancy in hoisting cycles between the curves given in the paper read by Mr. Sykes for the American Institue of Electrical Engineers at San Francisco and those given in the paper under discussion? In Mr. Sykes&apos; curves the acceleration period is shown to be 16 sec. for all depths from 2,000 to 4,000 ft. inclusive, while Mr. Moeller in Fig. 2 shows 25 sec. throughout the range and in Fig. 4 shows 35 sec. Mr. Moeller&apos;s curves also show the following reductions in the peak load during acceleration: Level, Feet Mr. Sykes, Horsepower Mr. Moeller, Horsepower 2,060 3,500 3,130 3,000 3,800 3,480 Fig. 2 4,000 4,100 3,800 2,250 1,595 Fig. 4 As the purchaser&apos;s specifications called for 15 or 16 sec. I would like to know whether or not any modifications have been made in the requirements since the equipment has been installed.

Jan 5, 1916

By H. R. Gardner

The heat treatmmt of plutonium was studied using the Jominy end-quenching technique commonly used for determining the hardenability of steel. Plutonium specimens were end-guenched from temperatures in each of the ß, y, d, d&apos;) and E phases. One series of specimens with a low-iron content, 165 pprn Fe, and another gvoup with a high-iron content, 678 pprn Fe, were used in order to study the effect of a Pu-Pu,Fe eutectic network on the hardness and micro-structure. Hardness traverses indicated no significant variations in hardness with either cooling rate or quench temperature. Metallographic studies indicated major effects on microstructure. Grain size was found to vary markedly with quenching temperature and cooling rate. It was determined that the Pu-PueFe eutectic network could be modified extensively by heat treatment, including spheroi -dization in the y phase and 6 phase below 413°C. An unidentified spheroidal inclusion was observed to go into solution in the delta and higher temperature phases. 1 HE element plutonium is unique among metals in that it has six allotropic forms in the solid state.&apos; These have been designated&apos; as the a, ß, y, d, d&apos;, and phases. The respective phase transformations occur at approximate temperatures of 122", 210°, 319°, 450°, and 480°C with a melting point at 640°C. With this number of phase transformations it becomes pertinent to consider the effect of heat treatment and cooling rate in the various phases on the microstructure and hardness of plutonium. To determine; the effect of a wide range of cooling rates, the Jominy end-quenching technique was applied to cylindrical plutonium specimens. In addition, since the presence of iron in amounts greater than 500 pprn is common in plutonium and results in a network of the Pu-Pu6Fe eutectic, it was decided to study heat treatment effects on two bomb reduced plutonium buttons with different iron contents. A low iron button containing 165 ppm Fe and a high iron button containing 678 ppm Fe were selected for this comparison. EXPERIMENTAL PROCEDURE Experimental Material. The cylindrical bars for Jominy quenching were cast from button stock in vacuo in MgO coated graphite molds. Metal pouring temperature was approximately 950°C and the molds were preheated to 300°C. The castings were machined to 0.5 in. diam. by 2.5 in. long cylinders. Chemical analysis and density data for the two groups of Jominy specimens containing different iron contents are presented in Table I. Except for iron, heats 19-12-1 and 20-2-1 are comparable within the limits of analytical accuracy. Representative specimens from the low-iron and high-iron bars were taken for metallographic examination. The low iron specimen was found to have extensive microcracking, Fig. 1. In addition, numerous unidentified spheroidal inclusions were present, Fig. 17. The average grain size of the low-iron plutonium is 0.068 mm, Fig. 4. In the high-iron plutonium, a Pu-Pu6Fe eutectic network is prominent, Fig. 7. The average size of the network is 0.100 mm. Unidentified spheroidal inclusions were also common in the high-iron plutonium. The average grain size of the high-iron plutonium is 0.036 mm. Experimental Technique. A Jominy end-quenching fixture was fabricated for glove box use. A 2.5 in. water height was used with an orifice of 0.250 in. ID. The orifice to specimen distance was maintained at 0.5 in. Annealing temperatures of 160°, 265°, 400°, 465°, and 535°c were chosen for the study of the effect of quenching from ß, y, d, d&apos;, and e phases on microstructure and hardness. During quenching, cooling curves were obtained from the Jominy specimens at distances from the quenched end of 1/16, 1/8, 3/8, 3/4, 1-1/4, and 2 in. Cooling rate calculations were made from the cooling curves for temperature intervals of 100° to 110° 160" to 170°, 330" to 340°, 420° to 430°, and 490° to 500°c. These temperature intervals were chosen

Jan 1, 1962

By W. L. Saunders

WHEN work was begun in September, 1910, on the rock excavation for the foundation of the gigantic dam at Valhalla, N. Y., which is to convert Kensico lake into an important storage reservoir of the Catskill Aqueduct system, one of the first steps taken by the contractor, H. S. Kerbaugh, Inc., was the development of a quarry to supply the stone needed in the construction work.The importance of a bountiful supply of suitable rock in an accessible location is apparent when it is considered that nearly a million cubic yards of cyclopean masonry will be contained in the completed structure, not to mention dimension and facing stones, concrete blocks, and mass concrete. The dam structure will be over 1800 ft. long and about 170 ft. above the present river bed. However, for a distance of some 800 ft., it will be carried down to solid ledge rock, which will make the finished structure about 300 ft. in maximum height. It will be about 200 ft. thick at the base and directly beneath the coping it will be 28 ft. thick. This dam will raise the reservoir surface 110 ft. above old Kensico lake. The reservoir capacity will be 29,000,000,000 gal.-equal to New York&apos;s total needs for over two months. The contract price for this work is nearly $8,000,000 and is second only in amount to the cost, over $12,600,000, of the Ashokan Reservoir work. Fig. 1 is a view of the dam site.

Jan 2, 1914