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By H. M. Otte

Certain choices for the shear elements of the inhomogeneous distortion in the phenomenological theory of martensite formation are examined for their agreement with crystallographic and X-ray data of iron alloys. The assumption that the shear elements must represent slip or twinning systems characteristic of bcc metals is found to covey all observations, even when a small uniform dilatation is taken into consideration. In bct martensite, (011) becomes a possible twinning or faulting plane, in addition to {112), and qualitatively similar X-ray line broadening is to be expected from both. The basic concept inherent in the current theoriesl-4 of the formation of martensite is that the interface between the parent (austenitic) and product (martensitic) phase is an invariant strain plane (i.e., one that is undistorted and unrotated). Experimental evidence that the interface is of such a nature is available in certain transformations2'5'6 but for the transformation in iron alloys direct observation has not proved enlightening. Internal strains resulting from the formation of the small martensite platelets within the parent austenite matrix7 make it difficult to produce the desired evidence. Indirect evidence, however, such as the continuity of scratches in passing from untrans-formed to a transformed region, strongly indicates that the habit plane in iron alloys is an invariant strain interface. The scatter in habit planes in a given specimen8 would suggest that internal stresses have a slight but definite influence. On the other hand, composition changes which affect the lattice parameter can alter the habit plane appreciably, and by an amount greater than the scatter.' The success of the theories depends on the choice made for the "inhomogeneous distortion" or "complementary shear'' in the analysis and also on the choice for the parameter 6 representing a small uniform dilatation. In the approach developed by Wechsler, Lieberman, and Read'," it is implicitly assumed that 6 is unity. In the case of iron alloys, all observations cannot be explained without varying either the inhomogeneous distortion or 6 . Bowles and Mackenzie3 considered only the effect of varying d. They found it difficult to reconcile the wide scatter of habit planes with the theory and were forced to the conclusion that it may also be necessary to consider variations or different choices of the inhomogeneous distortion. Wechsler and Read" considered a limited number of possible choices for the inhomogeneous distortion, but no variation in 6, though this could easily have been introduced if so desired. It is the purpose of the

Jan 1, 1961

By R. M. Waterstrat

The phase VPt has been reported to have a crystal structure of the B19 (AuCd) type at low temperatures.''' A recent investigation3 has indicated that this phase forms by an ordering reaction from the disordered fcc Pt(V) solid solution which is stable at high temperatures. olander4 has shown that there exists a close structural relationship between the orthorhombic B19 structure and a fcc structure possessing the L1 , (CuAu) type of atomic ordering. One may derive the B19 structure by a shear-like displacement of the atoms in the (002) plane of the ordered fcc lattice along the (010) direction through a distance equal to one eighth of the unit cell dimension, see Fig. 1, followed by an orthorhombic distor; tion of the cube axes such that a = 2.693A. h = 4.413A. and c =4.767A (estimated uncertainty 0.005A). Filings of this phase were produced by grinding a VPt alloy having the B19 structure with a diamond dental grinding disc. When these filings were subjected to X-ray diffraction examination, a pattern of a severely cold-worked fcc structure was obtained. higher solution temperature used (1200 C) or to a much lower oxygen pressure than he reported, due to transfer through many bends and tubes in his complicated apparatus. An interesting observation was made when an oxygen addition was attempted in a cylindrical sample of columbium in the cold worked condition rather than in the annealed condition. The interior of the sample re-crystallized during the oxygen addition at 900°C. The periphery, however. (1 mm) did not recrystallize. A similar sample without oxygen recrystallized throughout the entire cross section. It appears that the re-crystallization is hindered by interstitial oxygen. Presumably, the interior recrystallized before appreciable oxygen could diffuse into the core. This work was supported by the United States Atomic Energy Commission. When the filings were annealed in a high vacuum furnace for 15 min at 110O0C, however. they returned to the B19 structure perhaps as a result of reordering. Subsequent less-severe cold-working of these filings by grinding in a hardened steel mortar and pestle at room temperature produced a transformation into a cold-worked L1, structure which was slightly tetragonal. Thus it appears that the degree of deformation may influence the final structure. Considerable line-broadening was observed in X-ray diffraction patterns obtained from the cold-worked filings and therefore no attempt was made to obtain accurate lattice parameters. Vacuum annealing treatments at 1100'C intended

Jan 1, 1970

By J. E. Hilliard

A procedure is described for determining, from measurements on a section, the moments of any degree n (i.e., the mean value of Dn, where D is a linear dimension) of the size distribution of particles (or grains) in an opaque sarnple. The analysis is applicable to particles of alnzost any shape and to any mixture of shapes. However, if absolute values of the wloments are required, it is necessary to know what shapes are present and the relative frequency of their occurrence. In addition, certain shape-dependent parameters have to be evaluated before the formulas can be used. The measurement required is the distribution of intercept lengths. This can be determined either visually or with an automatic scanning instrument. Corrections me derived for the bias due to instrumental end effects. The proposed analysis has the following advantages over existing ones: 1) Confidence limits are easily estimated for the measured properties or, conversely, the number of counts required to achieve a given accuracy can be determined. 2) The analysis is not restricted to particles of a special shape. 3) The error resulting from any known degree of departure of the actual from the assumed particle shape can be estimated. 4) The computations are simple and, apart from a change in constants, are independent of particle shape. 5) The number of particles per unit volume can be determined by a simple counting procedure. MANY procedures have been described for determining the size distribution of particles from measurements on a section (or plane of polish). They differ from one another in the property measured on the section (radius, intercept length, profile area) and in the method used for the numerical solution of the integral equation relating the property to the particle size distribution. However, all existing analyses share at least two of the following disadvantages. 1) They are limited to a particular shape of particle (usually spherical). 2) It is very difficult to determine how the statistical sampling error is propagated into the computed size distribution. The investigator thus has no means of knowing the reliability of his result and, what is of equal concern, he is unable to estimate how many measurements are required to obtain a result of the required accuracy. 3) It is also difficult to assess the error resulting from any deviation between the actual and assumed particle shape. The foregoing limitations stem from the complex relationship between the particle size distribution and the distribution of the property measured on the section. As will be shown, they can be avoided by defining the size distribution in terms of discrete parameters

Jan 1, 1969

By John I. Yellott

SINCE the days of Newcomen and Watt, when men first sought to turn the energy of fuels to useful purposes, coal-generated steam has supplied most of the power needed for both stationary and mobile applications. The low efficiency and large water requirements of the nineteenth century steam-power plant caused many engineers to turn their thoughts toward more direct means of converting heat into power. As far back as 1791, John Barber secured an English patent on a combination' which he might well have called a "gas turbine." He proposed to generate procducer gas from coal or charcoal, to burn it under pressure in air obtained from a reciprocating compressor, and to drive a turbine wheel with the resultant hot combustion products. With the optimism characteristic of the inventor, he hoped that the turbine would not only operate his compressor but also perform useful work. There is no record that Barber ever built his machine, but if he had done so he would have learned that useful power can result from such a combination only when both turbine and compressor are highly efficient and when the temperature of the gas entering the turbine is not far below 1000°F. Hot-air prime movers continued to attract attention, and both Stirling in England and Ericsson in America2 built reciprocating engines that operated with some success upon coal-heated air. The internal-combustion engine, burning liquid fuels, supplanted the hot-air type, and, for the first time, challenged the supremacy of both the steam cycle and its familiar fuel, coal. LIQUID FUELS COMPETE WITH COAL As the increasing use of the automobile multiplied the demand for gasoline, the supply of residual fuel increased rapidly, and heavy oil declined in price to the point where it became competitive with coal. First in the marine field and later in stationary plants in areas adjacent to refineries, oil began to be widely used. Oil's greater convenience and higher heating value per pound of weight or per cubic foot of bunker space have caused it to take over much of the marine field. The introduction of the highly efficient diesel engine, capable of burning a fuel that is cheaper than gasoline, again threatened the position of coal, for the operating costs of the diesel became directly competitive with those of coal- burning equipment. In isolated power plants and smaller marine installations, the diesel provided the medium by which oil again successfully invaded fields formerly dominated by coal. The diesel engine, provided with an

Jan 1, 1946

By G. Gutzeit

An inner complex is a cyclic chemical structure containing an inorganic cation that is bound simultaneously to several atoms in a single organic molecule; on the one hand by means of ordinary valence bonds (electron exchange), on the other hand through the action of the electric field thus created, which satisfies the so-called secondary valences. The relative positions of the salt-forming and complex-forming groups are such that most frequently a four, five, or six-membered ring results through this double attachment of the cation.1-6 The formation of inner-complex ring systems depends not only upon the nature and suitable position of the salt-forming and complex-forming groups for ring closure, but, to a great extent, also on the nature of the metallic cation entering the reaction. This selective character of chelate-forming organic compounds is one of their most interesting and most valuable properties. As a matter of fact, the largest number of their practical applications is based upon their specificity.4,7-l3 Once a chelate compound is formed, its character is definitely "organic" in nature. In other words, its properties are conditioned to a much larger degree by the carbon chains or rings than by the metallic atom. Many inner complexes are soluble in nonpolar solvents such as benzene, paraffin oil or carbon tetrachloride, while the chelate-forming reagent before closure of the metal-organic ring is water soluble. (Example: copper complex of salicyl-aldoxime') It is obvious that such particular properties as those indicated above can be utilized whenever specificity and practically complete binding of inorganic ions into an undissociable complex are required. One of the well-known applications of chelate-forming compounds has been the development of specific reagents in analytical chemistry, creation of the spot-test method,4,14-16 and the application of the same principles to the contact print method for determining minerals." Chelate-forming Compounds as Collectors In the field of flotation, where selectivity is often a quality of paramount importance for the collector, various workers have lately attempted to apply their knowledge of specific organic analytical reagents to this purpose. A. C. Vivian18 has concentrated cassiterite by using ammonium nitrosophenylhydroxyl-amine (Cupferron) C6H5NO(=NONH4). Holmanl9 has tested dimethylglyoxime for the flotation of nickel oxide minerals, while deWitt has shown in a series of systematic experiments that alpha-diox-imes were generally selective collectors for nickel ores. Taurin NH2(CH2)2S03H has been proposed for the concentration Of Oxidized lead ores.19 Diphenylthio-carbazone

Jan 1, 1947

By Alexander Coucoulas

FABRICATION of thin-film circuits deposited on glass substrates requires the formation of permanent electrical contacts. Since thin films are in the order of a few thousand angstroms thick and are deposited on nonconductive surfaces such as glass, new methods of lead attachment are being pursued in the microelectronics industry. Ultrasonic welding is being considered in thin-film technology since joining can be accomplished between a wide variety of dissimilar materials.l,' Ultrasonic welding is accomplished by a transducer-coupling-tip system which converts high-frequency electrical energy into mechanical vibrations and delivers it into the weld region. During the process the tip oscillates in a direction parallel to the surface of the weldments, inducing shear stresses in the work pieces which are clamped between the tip and anvil. Though the basic bonding mechanism is not clearly understood, it has been described as closely akin to friction welding. In the course of an investigation concerned with ultrasonic we!ding of aluminum wires to tantalum thin films (1400A) deposited on glass, low weld strengths were related to glass failure. Upon investigating this condition, an improved method of bonding was developed where the aluminum was held at a temperature where a minimum amount of strain hardening occurred during the introduction of ultrasonic energy. Experimental Procedure. Aluminum wires (0.015 in,) were bonded to tantalum thin films with an optimized set of welding parameters (power, time, clamping force) employing a commercial 100-w 60-kc ultrasonic welder. Forty-five degree shear-peel tests, where the lead is pulled at a 45-deg angle with respect to the substrate at 0.2 in. per min, produced a large variation from zero to the strength of the wire, Table I. Inspection of the weld region generally revealed: glass cracking before and after testing; the removal of glass nuggets from the substrate by the lead during testing, Table I; thin-film penetration. In an effort to improve the shear-peel strength, the aluminum between the tip and substrate was heated above ambient temperature through an argon gas media prior to and during welding with the same parameters employed above. With the addition of heat: wire deformation was increased; shear-peel tests all failed at the weld-wire junction, leaving the bonded portion undisturbed; no evidence of glass cracking or film penetration prior to or after testing was observed. In order to prevent failure at the weld-wire junction due to excessive wire deformation, 0.035-in. aluminum wires were welded to tantalum thin films with an optimized set of welding and heating parameters. As

Jan 1, 1967

By G. A. Crowe, W. T. Bishop

WHILE the literature in the United States on general polarographic technique is extensive, very little appears to be directly applicable to the analysis of flotation tailings. For this reason, it seemed worth while to present a few polarographic methods of ore analysis that have been in constant use in the laboratories of the Hercules Experiment Station for the past few years. At the time of our initial investigation of the polarographic method, there was little or no mention of its specific application to flotation tailings. It was therefore necessary for us to establish suitable conditions for the analysis of our flotation tailings and to consider possible interfering constituents. The polarograph, or dropping mercury electrode, method was discovered in 1925 by J. Heyrovsky and M. Shikata,1 of the Charles University, Prague. This method has since received extensive development and the literature contains many articles on the use of the polarograph for the quantitative determination of metals as well as anions, oxygen in solution, and reducible organic compounds. Kolthoff and Lingane,2 by the publication of their book, "Polarography," in 1941 did much to advance the knowledge and use of the polarograph. In chapter 25 of that book, methods for the polarographic analysis of brass, steel and iron products, alloys, and zinc ore are given. Aluminum,3 cadmium,3.4 cobalt,4 copper,3-9 gold,10 iron,3,11 lead, 3,12,13 molybdenum," nickel,4.8,9 tin,15 and zinc3,4,5,7 in ores have been analyzed by the polarograph. However, most of the work on tailing samples has been published in Russian journals and translations are not yet readily available. In this paper we will describe the method that was developed and used in our laboratory for the determination of copper, zinc, and lead in flotation tailings. PRINCIPLE OF THE METHOD The polarograph is an instrument for applying a potential to a mercury pool and a dropping mercury electrode separated by a solution, and for measuring the resultant electrical current. The procedure is essentially a small-scale electrolysis, in which the voltage required to reduce or oxidize the material identifies it qualitatively and the current measures the concentration quantitatively. Different constituents in a sample may often be determined simultaneously provided they reduce at sufficiently different voltages. An example is the determination of copper and zinc in the same solution. The reduction potentials are quite far apart, as shown in Fig. I. The polarographic method is particularly useful in the range of concentration between those normally determined by spectographic and chemical methods. In

Jan 1, 1946

By Grover J. Holt

A detailed description of the many variations in iron mining and transportation practice in Minnesota would require much space. Since a fairly detailed description of the practices then in use was published in the guidebook issued in connection with the meeting of the Institute on the iron ranges in 1920, and subsequent developments have been described by E. E. Hunner, M. H. Barber,2 and A. E. Anderson, J. M. Riddell and G. J. Holt,³ it will not be necessary here to do more than review the highlights of current practice. Details on any points of interest can be obtained through correspondence with the operators involved. † The iron ores of Minnesota, which have been formed through enrichment of the iron formation in which they occur, largely by the removal of silica, are usually covered by a blanket of glacial drift known locally as "surface." Surface material, including sand, clay, hardpan and boulders, makes up the greater portion of the stripping in open-pit operations. In some instances, stripping also includes taconite and paint rock," directly below the surface material and overlying the ore. Tacenite is the iron formation, a ferruginous chert with inter-bedded slate layers. :'paint rock" is a local term for oxidized slate layers inter- bedded in the iron formation, high in phosphorus, alumina and moisture. The iron ores fall into two classes: (I) direct shipping (merchantable ores or ores requiring no treatment except possibly crushing or screening to make an acceptable sized product), and (2) ores requiring beneficiation (such as sintering, drying, washing, jigging, high-density treatment, or magnetic separation in the case of magnetite). The Mesabi Range produces chiefly soft Bessemer and non-Bessemer ores. The Cuyuna Range produces mainly low-manganese brown ore and high-manganese black ores, with some iron ore. The Vermilion Range yields mainly Bessemer and non-Bessemer iron ore, with some hard or lump ore that finds use in the open hearth. Open-pit mining is limited to the Mesabi and Cuyuna Ranges but underground mining is done on all three. The choice of mining methods is determined by the relative economics of overburden-removal and shaft-mining costs. Stripping Practice Common practice has been to remove the bulk of the overburden during the winter season and to mine during the summer, In- the present emergency many operators are forced to forego the economies attained by year-round utilization of paper. and to equip for, and carry on, stripping and mining simultaneously. In the normal years or lean years to come, most properties probably will be overequipped and high depreciation charges Will have to be absorbed.

Jan 1, 1943

By Brison Robertson, W. P. Fishel

THE carbide-forming tendencies of the various steel-alloying elements, or their affinities for carbon, is a subject that has received considerable attention, but little more than a probable arrangement of the elements as to their carbide-forming tendencies has been proposed. The physical properties of alloy steels depend upon the relative proportions of the elements present and their combinations. One important phase of this subject is the distribution of carbon between the various elements present. The distribution of carbon between iron and other elements evidently will depend upon: (I) the affinity of each for carbon; (2) the relative atomic masses of the elements present; and (3) the possible formation of compounds between the alloying elements and iron and between the elements themselves. In ternary steels the case is simplified, especially in systems in which the element and iron form no compounds. In such systems iron and the alloying element are competing for the carbon present. In this work the distribution of carbon between titanium and iron has been studied by measuring the relative amounts of iron carbide and titanium carbide present in a series of annealed steels in which the ratio of titanium to carbon extended from 0.527 to 4.61. EXPERIMENTAL PROCEDURE Ten Fe-Ti-C alloys, weighing about 250 grams each, were prepared by melting under a vacuum, in an induction furnace, Armco iron, carbon-free ferrotitanium (25 per cent Ti), and pure carbon. Vacuum melting prevented the formation of titanium oxides and nitrides, which would complicate the problem. The melts were made in graphite crucibles lined with sintered magnesium oxide. The ingots were cooled in the furnace under a vacuum and were then completely annealed at 950°C. The determination of the amount of titanium carbide present was based upon the established insolubility of titanium carbide in boiling dilute (I :4) sulphuric acid, and the complete solubility of free titanium and titanium-iron compounds in this acid. High-carbon ferrotitanium, which had been treated to remove free Ti and Fe, was found to be completely insoluble in the acid; and the carbon-free ferrotitanium used in making the alloys was found to be completely soluble. Others 1,2 have reported the insolubility of titanium carbide in sulphuric and hydrochloric acids. Turnings from the ingots were digested with boiling sulphuric acid (1:4) until all action had ceased. The carbide residue was filtered off and analyzed for titanium, and in some cases for carbon. This represents the titanium that was united with carbon. The filtrate from the carbide residue contains the portion of the titanium that wasin solid solution in the ferrite. Titanium

Jan 1, 1944

By E. DeGolyer

(San Franciso Meeting, September, 1915) I. INTRODUCTION THE Furbero oil field lies in the Gulf coastal plain of Mexico between the important ports of Tampico and Vera Cruz and about one-third of the distance between the two points from the latter (Lat. 20° 22' N., 97° 30' W. Gren.). It is in the State of Vera Cruz, about 14 miles west by south of the village of Papantla in the canton of the same name, and is the most southern of the developed oil fields of the Tampico-Tuxpam region being a distance of 50 miles south by east from the Potrero del Llano field and 42 miles in the sane direction from the Alamo field. The field has been developed by the Oil Fields of Mexico Co. and is in the midst of a large block of lands owned or leased by then. Communication is through the port of Tuxpam with which it is connected by a narrow-gauge railway and 6-in. pipe line some 52 miles in length. This field is of more than ordinary interest since it represents a type of oil deposit hitherto unknown. So far as I am aware, no other commercially valuable deposit of oil is known to occur under conditions of accumulation similar to those found here. The igneous nature of the so-called `sand' encountered in drilling was not recognized until a number of wells had been drilled; and it was not until recently. that the geological relations of the sill or laccolith, which gives rise to the accumulation of oil, were known and the so-called `anticline' was known to be, in part at least, the result of igneous intrusion. Geological surveys in this general region were made in 1900-1901 by W. H. Dalton and in 1907-1909 by P. C. A. Stewart, F. W. Moon, Leonard V. Dalton, and Dr. Max Muhlberg. More recent surveys have been made, however; under the direction of the author, by E. L. Ickes, B. C. Belt, B. Hartley, and Harve Loon-us. Notes of the earlier examinations were not available with the exception of the report by Dr. Muhlberg who apparently first recognized the true nature of the Furbero intrusion. This paper is indebted to his work and that. of the more recent surveys for much of the detail regarding stratigraphy and to Messrs. Percy Furber and Arthur C. Payne, President and General manager of the Oil Fields of Mexico Co. for permission to publish, and for much of the in-

Jan 9, 1915

By L. D. Fetterolf, G. T. Mahler, W. M. Peirce, R. K. Waring

UNTIL recently, the only commercial method of producing magnesium has been fused salt electrolysis, despite a considerable amount of experimental work on the direct reduction of magnesium oxide. In this early work, a number of investigators demonstrated that magnesium oxide would react with any one of several reducing agents to produce magnesium vapor, but that the mixture of magnesium oxide and reducing agent must be heated to a high temperature even in a vacuum. In particular, it was demonstrated that silicon and aluminum are effective reducing agents and that when either of these is used the magnesium vapor can be condensed to massive metal. In spite of this knowledge, no successful commercial reduction process was developed, at least in this country, because of the operational difficulties imposed by the requirement of high temperature and vacuum and because of the high cost of the reducing agent. The outstanding experimental work done by Pidgeon, who carefully reviewed all of the known methods of making magnesium and then selected ferrosilicon reduction, overcame some of the operational difficulties. The process developed by Pidgeon comprises briquetting a mixture of calcined dolomite and reducing agent, pre-heating the briquets to about 600°C. in an externally heated alloy retort, reducing the MgO with silicon in an evacuated horizontal alloy retort heated externally to about 1150°C., and condensing the magnesium vapor to a solid in a cold extension of the retort projecting beyond the fr6nt of the furnace. A major advantage of Pidgeon's process is that the retort is not cooled down between charges. Earlier investigators had used apparatus that necessitated cooling and reheating of the retort between charges. Early in January 1942, when the War Production Board was considering the Pidgeon process for quickly increasing the production of magnesium, The New Jersey Zinc Co. offered to have a research investigation of the process carried on, with the hope of assisting in its further development. This offer was accepted, and a two-retort pilot plant was built at Palmerton and put in operation on Jan. 29, 1942. An intensive investigation of certain phases of the process was carried out in the ensuing four months. This investigation was completed in the last part of May 1942, and the pilot plant was then shut down. Subsequently, The New Jersey Zinc Co. was requested to have further development work done on the process, and a more extensive investigation was undertaken in August I942 under contract with the War production Board and under the super- vision of the War Metallurgy Committee. This paper describes the phases of the investigation that are thought to .be

Jan 1, 1944

By F. E. Brackett

THE simplicity of the propeller or disk fan, its small size and low cost, has, in recent years, led to an extended use of ventilators of this type at mines where only slight pressure is required. On this account the author of this paper has prepared for the new edition of Peele's Mining Engineers' Handbook a more accurate method of computing the required size, power, and so forth, than was possible for the first edition. The main object of this paper is to set forth the data collected in the course of that work, and to discuss the subject with more latitude than would have been advisable in a handbook, even if space had been available. Theory of Fans A great deal has been written about the theory of fans from Rankine's time down to the present. Nevertheless a rigid mathematical analysis of the propeller fan seems to be wanting. A general idea of the mechanics and difficulties in the way of analysis may be gathered from the following: The useful pressure and velocity effects of the oblique impact of the vanes on the axial current would evidently be nil if the blades were perpendicular to the plane of rotation, or if they were of such helicoidal form that the screw pitch multiplied by the speed represented an axial velocity agreeing with the actual velocity. Somewhere between these zero angles there is a pitch which, under given conditions of flow, would produce the maximum useful effect. A true helicoidal blade can be so arranged that it would offer no retarding effect on the air current at any part of the wheel, provided the axial velocity be assumed the same in all parts of the cross-section of the air course, but if plane surfaces are used, it is possible, under some conditions, that the air would be retarded at the middle parts of the wheel while it was accelerated at the circumference. Whatever be the form of vane, it seems evident that the tips are far more effective than the center of the wheel, because of their higher velocity. For this reason some investigators believe that a backward current forms through the middle of the wheel and that part of the air is circulated in a radial axial loop. Ignoring the possible existence of this eddy and the friction of the walls of the air course; and assuming the axial velocity of the air through all parts of the wheel, some rational analysis of the impact might be made according to the theory of deflecting surfaces, were it not

Jan 1, 1928

By F. M. Perkins, R. H. Jamison

Publications concerning scaling laws for laboratory flow models of oil reservoirs indicate that the relative permeability and capillary pressure relations must be the same functions of saturation in the model and its prototype. In this paper, the relative permeabilities and saturations are redefined in a way which permits one to have diflerent relative permeability and capillary pressure relations in the model and prototype. The development of the new scaling criteria is demonstrated by deriving scaling laws for one simple flow problem. INTRODUCTION The successful application of information gathered through bench-scale model studies to the prediction of multi-phase fluid flow behavior in petroleum reservoirs requires careful consideration of the scaling criteria. The requirements which must be met for a small-scale model to duplicate the behavior of a much larger reservoir prototype have been discussed by Leverett, et al,' Rapoport,2 and Geertsma, et al.3 According to these authors, the relative permeabilities to water, oil and gas and the dimensionless capillary pressures must be the must have the same values in the model and prototype. Furthermore, they point out that the viscosity ratios must have the same values in the model and prototype. In addition to these requirements, other scaling criteria are given which, when considered, usually dictate a much higher permeability in the model than exists in the reservoir. Since the more permeable model sands may have connate-water and residual oil saturations quite different from those in the prototype, the scaling requirements pertaining to the dependence of relative permeabilities and dimension l ess capillary pressures on saturation usually are not met. Also, if the model fluids are selected to give equal viscosity ratios in the model and prototype, one may find greatly different mobility ratios* in the two cases and, therefore, may expect grossly different flow patterns. For this reason, Craig, et al,' correlated the results of their model studies with mo- bility ratio rather than with viscosity ratio. As yet, however, no satisfactory method has been advanced which permits use of anything other than the scaling requirements outlined in the previously mentioned papers. The purpose of this paper is to present a method of developing a set of scaling criteria which permits different relationships between saturation and relative permeability or capillary pressure in the model and prototype. Rather than attempt to report scaling criteria for a variety of practical situations, this paper demonstrates by use of one simple example how the modified scaling criteria are derived.

By Benjamin Lustman, Robert F. Mehl

THE study of the high-temperature oxidation of pure metals, intensively pursued experimentally since the pioneer work of Pilling and Bedworth1 and supplemented by the recent theoretical work of Wagner2 is now well advanced. The important field of low-temperature oxidation-i.e., oxidation extending only through the temper color range of thicknesses with the formation of thin oxide layers in the range from o to 1000-2000 Angstroms-has not, however, reached so satisfactory a state, owing largely to the experimental difficulties that attend the formation and study of thin films; most of the work has been performed on abraded specimens whose surface irregularities approximated the thickness of the films formed. It has been pointed out that the rates of oxidation of different crystal faces are different and that the difference may be related to the orientation relationships that obtain between the metal crystal and the superimposed oxide crystal; it has also been suggested that this orientation dependence should manifest itself in rates of oxidation and perhaps also of corrosion in aggregates bearing preferred orientations. 3,4 An attempt to measure the rates of oxidation of different crystal faces of alpha iron demonstrated this difference in rate,4 but the dependence of rate on orientation was not simple; the method of measuring thickness, consisting of a color comparison with barium stearate multi-films of known thickness, was not wholly satisfactory. For these reasons it was felt that a study of the rate of oxidation of single crystals prepared with surfaces as smooth as possible, using a sensitive method giving true film thickness, should be profitable. Copper was chosen because of the ease of reduction of the primary oxide film and because the orientation relationships between metal and oxide and the composition of the oxide films formed at low temperatures are known; for thin films formed at low temperatures, Cu2O alone occurs.22-24 EXPERIMENTAL PROCEDURE Various methods of surface preparation were attempted in order to obtain a surface that would oxidize uniformly and reproducibly. Electrolytic polishing by the method of Jacquet5 and electrolytic and mechanical polishing followed by annealing in vacuum and in purified hydrogen at various temperatures were tested. The procedure finally adopted consisted in a fine metallographic polish followed by an anneal in purified hydrogen at temperatures of 900º to 1000°C. for 12 hr. or more. The surface so produced was very bright and smooth, with no trace of specular etching (though some grain-boundary etching was observed); indeed, fine scratches produced by the final polish were entirely removed by the high-temperature anneal.

Jan 1, 1941

By Herbert M. Wilson

We of the employer class represent labor in the social organization and in industry just as truly as do those who labor only with their hands, and, because our labor is chiefly with our brains, the duty is all the more imposed upon us to use those gifts in which we excel in helping steer a clear course through the turbulent waters in which we are now enmeshed. Only their selfish engrossment in the daily tasks they were employed to perform could possibly have permitted the great majority of the intelligent and industrious German people to become terrorized by a handful of the idle, the vicious, and the criminal, whom the elections to the National Assembly showed to be in as pitiful a minority as they are in Russia, in this, and in other countries. It is the leisure unemployment of the I.W.W.'s, the Bolsheviki, and the Sparticans that has enabled them to devote their whole time to a concerted and aggressive struggle against the great majority of those of the world's workers who are unorganized, and who are therefore even in opposition one to the other. In union there is strength, and this was never better illustrated than by these conditions. The great fallacy of our previous attitude toward social and industrial problems has been the belief that labor, by which we commonly mean organized or physical labor, is something antagonistic to and having a different object in life from that great body of unorganized laborers who work with their brains. Our difficulty has been our lack of will or opportunity to think. The hurry of our daily struggle to earn our livelihood under the nerve-racking pressure of modern civilization has left us no opportunity for quiet thought and study. The physical laborer, and above all the laborer in the mines, on the other hand, has all his hours of toil in which to think over, in all their varied aspects, those problems that concern his immediate, personal well-being. As a result he has arrived at perhaps a more true appreciation of the facts of life in their relation to social and industrial conditions than we. Have we not too readily adopted the view that, as the managers of industry under the direction of capital, it has been our duty to think and act in opposition to labor, rather than to realize that we also are laborers, have like aspirations, and should participate in a free and aggressive solution of these problems rather than leave their solution

Jan 1, 1919

By Brison Robertson, W. P. Fishel

The carbide-forming tendencies of the various steel-alloying elements, or their affinities for carbon, is a subject that has received considerable attention, but little more than a probable arrangement of the elements as to their carbide-forming tendencies has been proposed. The physical properties of alloy steels depend upon the relative proportions of the elements present and their combinations. one important phase of this subject is the distribution of carbon between the various elements present. The distribution of car. bon between iron and other elements evidently sill depend upon: (I) the affinity of each for carbon; (2) the relative atomic masses of the elements present; and (3) the possible formation of compounds between the alloying and iron and between the elements themselves, In ternary steels the case is simplified, especially in systems in which the element and iron form no compounds, In such systems iron and the alloying element are competing for the carbon present. In this work the distribution of carbon between titanium and iron has been studied by measuring the relative amounts of iron carbide and titanium carbide present ill a series of annealed steels in which the ratio of titanium to carbon extended from 0.527 to 4.61. Ten Fe-Ti-C alloys, weighing about 250 grams each, were prepared by melting under a Vacuum, in an Induction furnace, Armco iron, carbon-free ferrotitanium (25 per cent Ti), and pure carbon. Vacuum melting prevented the formation of titanium oxides and nitrides, which would the the problem. The melts were made in graphite crucibles lined with sintered magnesium oxide. The ingots were the in the furnace under a vacuum and "'ere then completely annealed at 950°C. The determination of the amount of titanium carbide present was based upon the established insolubility of titanium carbide in boiling dilute (1:4) sulphuric acid, and the complete solubility Of free titanium and titanium-iron compounds in this acid. High-carbon ferrotitanium, which had been treated to remove free Ti and Fe. was found to be completely insoluble in the acid; and the carbon-free ferrotitanium used in making the alloys was found to be completely soluble. Others have reported the insolubility of titanium carbide in sulphuric and hydrochloric acids. Turnings from the ingots were digested with boiling sulphuric acid (1:4) until all action had ceased. The carbide residue was filtered off and analyzed for titanium, and in some cases for carbon. This represerifs the titanium that was united with carbon The filtrate from the carbide residue contains the portion Of the titanium that was in solid solution in the ferrite. Titanium

Jan 1, 1945

By G. A. Crowe, W. T. Bishop

While the literature in the United States on general polarographic technique is extensive, very little appears to be directly applicable to the analysis of flotation tailings. For this reason, it seemed worth while to present a few polarographic methods of ore analysis that have been in constant use in the laboratories of the Hercules Experiment Station for the past few years. At the time of our initial investigation of the polarographic method, there was little or no mention of its specific application to flotation tailings. It was therefore necessary for us to establish suitable conditions for the analysis of our flotation tailings and to consider possible interfering constituents. The polarograph, or dropping mercury electrode, method was discovered in 1925 by J. Heyrovsky and M. Shikata,1 of the Charles University, Prague. This method has since received extensive development and the literature contains many articles on the use of the polarograph for the quantitative determination of metals as well as anions, oxygen in solution, and reducible organic compounds. Kolthoff and Lingane,² by the publication of their book, "Polarography," in 1941 did much to advance the knowledge and use of the polarograph. In chapter 25 of that book, methods for the polarographic analysis of brass, steel and iron products, alloys, and zinc ore are given. Aluminum,³ cadmium,³,4 cobalt,4 cop-per,³-9 gold,10 iron,3,11 lead,³,l2,l³ molybdenum,14 nickel,4,8,9 tin," and zinc³,4,5,7 in ores have been analyzed by the polarograph. However, most of the work on tailing samples has been published in Russian journals and translations are not yet readily available. In this paper we will describe the method that was developed and used in our laboratory for the determination of copper, zinc, and lead in flotation tailings. Principle OF the Method The polarograph is an instrument for applying a potential to a mercury pool and a dropping mercury electrode separated by a solution, and for measuring the resultant electrical current. The procedure is essentially a small-scale electrolysis, in which the voltage required to reduce or oxidize the material identifies it qualitatively and the current measures the concentration quantitatively. Different constituents in a sample may often be determined simultaneously provided they reduce at sufficiently different voltages. An example is the determination of copper and zinc in the same solution. The reduction potentials are quite far apart, as shown in Fig. I. The polarographic method is particularly useful in the range of concentration between those normally determined by spectographic and chemical methods. In

Jan 1, 1947

By F. C. Oliphant, George H. Fancher

Two samples of drilling mud from the Hastings oil field, Texas, were tested, and the solids in each were separated into small fractions of a limited range in particle size. The mineral composition of each fraction by X-ray analysis is reported, and the results are interpreted in relation to other measured quantities, such as the physical properties of the original samples and the density of the various fractions. It was found that only 7 to 8 per cent by weight of the solids was of colloidal dimensions and that neither of the samples contained montmorillonite but did contain illite. Considerable calcite was also found. These data should be useful to the geologist interested in the origin and history of sedimentary strata as well as to the petroleum engineer. Introduction The questions, What is good drilling mud? What constitutes bad drilling mud? are pertinent, because the proper use and control of drilling fluids has been a factor of great importance in the successful drilling and completion of oil wells since the days of Captain Lucas. Adequate control of the characteristics of drilling fluids has assumed greater significance comparatively recently because of the problems introduced by caving formations in deep wells, costly blowouts and impressive mud bills. Much is known about the solution of some of the problems but, despite extensive research directed toward a better understanding of the physical and chemical properties of clay suspensions, it is difficult to define precisely a drilling mud, and much more difficult to say what constitutes a good mud. It is generally believed that the smaller particles of a drilling mud greatly affect its physical properties. In fact, it is customary to blame the colloids in a mud for nearly everything that goes amiss, because colloidal properties have effects out of all usual proportion on viscosity, filtration rate and reaction to electrolytes. It is germane to know whether drilling muds possess colloids and if so, the quantity and kind. Source oF Samples Two drilling muds from the Hastings oil field, Brazoria County, Texas, were selected because it is generally agreed that in this oil field good natural muds made solely from formations penetrated by the drill can be used until the well is nearly ready for completion. Customary drilling procedure in this field is to spud in with water, set a protective string of pipe, drill to 2500 ft. and set the surface casing. Drilling is continued to 5500 ft. with no treatment of the drilling fluid other than addition of water to

Jan 1, 1943

By M. R. Tek, F. H. Poettmann, M. L. Grove

The general problem of single-phase natural gas flow through porous media has been considered both by mathematical analysis and field experiments. Theoretical studies on the fluid dynamics of natural gas wells resulted in derivations of expressions which permit a ber-ter understanding of the flow mechanism for conditions under which Darcy's law is no longer valid. In applying these results to natural gas production and testing technology, special emphasis war placed on the study of low permeability, slowly stabilizing formations. These applications resulted in a method of predicting the performance coefficients of tight natural gas wells. The calculation of the performance coefficient requires the determination of the "test-index", pkh/µ, the drain- age radius, R, and the effective wellbore radius, rw. Methods for estimating these parameters from field data were also developed. Field data from 15 wells were collected and analyzed. The measured values of the performance coefficients were compared with the predicted values. This statistical evaluation gave a bias of 7.14 per cent and a standard deviation of 11.6 per cent. INTRODUCTION The performance of a natural gas well is determined by the physical properties of the reservoir rock, the extent and the geometry of the drainage area, the properties of the flowing fluid, and the conditions of pressure distribution within the drainage matrix. The relation between the quantity of gas delivered and the pressure drop within the reservoir is characteristic of the behavior of each well and is often referred to as the back-pressure behavior of the well. It is well established that for normal, single-phase gas wells the relationship between the gas delivery rates and the bottom-hole pressure take, in general, the form, Q = c(P3 8 -P2 1)n. ,.......(1) where C is the performance coefficient, and n is the exponent corresponding to the slope of the straight-line relationship between Q and (P2 s, — P2 l) plotted on logarithmic coordinates. The determination of a well's performance by the back-pressure behavior not only permits the production engineers to analyze many operating problems, but also provides necessary information useful and essential to predict the future development of the field.' Important engineering and production problems such as calculation of gas deliverability into a pipeline at a predetermined line pressure, design and analysis of gas-gathering lines, determinations of spacing and number of wells to be drilled during field development to meet future market or contract obligations, etc., all depend, at least in part, on the availability and use of reliable back-pressure curves.' In the past the behavior of gas wells was evaluated

Jan 1, 1958

By W. Rostoker

INTRODUCTION THE process of diffusion alloying of mixed powders offers attractive possibilities both commercially and experimentally. It avoids the fabrication difficulties arising from high alloy contents. Indeed, the process is facilitated by larger alloy additions. The direct formation of the part or test piece and the opportunity to perform machining operations under more favorable conditions are of no small importance. However, it is necessary to make only brief mention of the interesting features. As yet there have been few attempts to study this process in detail and to carry it to completion, if such is possible. It was intended not only to measure the intermediate and optimum magnetic properties of sintered alloys but to use magnetic testing itself as a means of following the progress of alloying under various conditions. Having established that alloys could be successfully synthesized by this technique, the opportunity was taken to study the magnetic properties of several alloys of iron and silicon which had hitherto been too difficult to prepare in suitable test piece form, While avoiding some of the difficulties inherent in the fabrication of alloys by orthodox methods, the diffusion alloying process introduces a few of its own. The first of these is the evaluation of the approach to homogenization. In recent years some notable contributions have been made to this question, but considerable uncertainty remains in its definition and evaluation. This work has concerned itself with further study of this problem and it is hoped that more light has been shed on it, The second of these difficulties arises from the presence of porosity. It is inevitable that in the consolidation of a loose bulk of powder, there should remain some voids unless extremely high pressures are repeatedly applied. It was therefore of importance to investigate their effect on magnetic properties. Recently this effect has been studied and certain predictions made of its behavior. It is believed that the experimental results presented here provide a sound substantiation of the theoretical treatment. The attempt has been made to synthesize five alloys of the iron-silicon system and three each of the iron-nickel and iron-cobalt systems. A series of experiments was also conducted on some of these alloys to test their susceptibility to heat treatment. Some unfortunate experiences have provided opportunity to report data on the deleterious effects of nitrogen on magnetic properties when present as a contaminant in protective atmospheres. MATERIALS, PREPARATION OF SAMPLES AND TESTING The purest materials available were employed for this work. A specially purified,

Jan 1, 1948