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By Ronald L. Longwell

PROPERTY LOCATION Located in the Copper Creek area of the Galiuro Mountains, the Old Reliable is on ground first claimed for mineral value during the Civil War. The deposit was mined sporatically from 1880 to 1919 and again in 1953 and 1954, with a total of about 30,000 tons of ore removed. The ore body is a near vertical breccia pipe containing approximately 4,000,000 tons of 0.80% copper with mineralization occuring as chalcocite, chalcopyrite, malachite, chalcanthite, and chrysocolla. The host rocks are extrusive lavas of cretaceous age which were intruded and mineralized by Copper Creek Granodiorite, which is Laramide in age. The ore zone, which occurs on the toe of a ridge, is about 300 feet by 600 feet in plan, with the bulk of the deposit extending from the surface to a depth of 500 feet.

Jan 1, 1974

By Frank Firmstone

IN 1871, two furnaces at the Glendon Iron Works, which had been blown out on account of the "coal strike," were altered from the open-top plan with side flues for collecting the gas, to closed tops with cup and cone. In one furnace the suppression of the side flues permitted a considerable alteration in the profile, but in the other (No. 5) no change in this respect was made; the side flues were simply bricked up and new ones cut through the sides close to the top. This furnace was in blast over four years, and we can, therefore, form a pretty good idea of the effect of the alterations on the furnace process. The principal dimensions are; Height 72'; greatest diameter, 18'; diameter at tuyeres, 8'; diameter of top, 10'; diameter at stock line (point at which the top of the materials is kept), 11'; cubic contents, 11,900 cubic feet. The table below shows the average results for periods of twenty-six weeks each. 1st, of the open-topped furnace; 2d, of the furnace with the first charger used, which was an ordinary cup and cone (diameter of cone 5' 2") 3d, with the charger used ever since, a "double" cone 7' 5" diameter outside, having a central opening 3' in diameter. The diagram (Plate II) shows the daily variations, in the grade of the irons for the same periods.* * In calculating the average grade of each day's iron, each twelve hours was taken by itself whenever more than two kinds of iron were made in the 24 hours, and the diagram drawn accordingly. By counting, it will be found that there were more such days with the single cone than with the "double" cone, and more with this than with the open top. † Anthracite.

Jan 1, 1876

EDWARD B. GRUBB, Burlington, N. J.: In connection with the discussion relative to the effect of vibration upon the molecular structure of wrought-iron, I would like to call your attention to the following extracts from a work by William

Jan 1, 1897

air-lift and equipped with tapered tubing of proper design, we would have a gas input consumption of about 2500 cu. ft. per bbl., which at 3 to 4c. per 1000 cu. ft. would be 7 1/2 to l0c, per bbl., and there would be very infrequent loss of production due to stoppages. It has been demonstrated that with efficient design of air-gas lift, the production of wells can be increased much beyond that obtained with the former type of air-lift employed; also that small wells can be operated by air-lift with tapered tubing at a cost that places this method in competition with beam pumps in many fields. The next step in conservation that the writer expects to have an opportunity to demonstrate is that of restoring the pressure in a pool and producing by air-gas lift all of the oil possible to lift economically. This combined operation is probably the method toward which we shall eventually be working in recovering the maximum quantity of oil from pools where the oil is recovered through bore holes. General Discussion on the Air-gas Lift H. P. Porter, Tulsa, 0kla.—The papers presented at this meeting contain a great amount of valuable information. Wonderful progress has been shown in the development of air and gas-lifts. There has been nearly everything brought out that touches upon the subject. The real point that is lacking is exact knowledge of the velocity with in the flow column which will produce the best effect—that is the thing we must know more about. Velocity in Gas-lift Flow In other lines of industry the matter of velocity of fluids in pipe lines has been well analyzed and there are known laws by which to calculate velocity of flow; for instance, in irrigation work large pumps are designed with intake pipos to employ an intake velocity of 4 ft. per scc. By reduced cross-sect'ion the velocity is increased rapidly as it enters the pump and the discharge rate is at 12 ft. per src., which in turn is reduced in the discharge column to 4 ft. per sec. Crushed coal, grain and granular material is found to be best conveyed by air when a pneumatic conveyor is employed at 100 ft. per sec. As in the design of a pumping plant or a pneumatic conveyor, the velocity at the lower end of the column in the flowing well must be controlled within certain limits for best results. Mr. Griswold, I believe, stated that they had velocity as low as 15 it. per scc. and from that up to 78 ft. per sec. Mr. Pierce and Mr. Lewis showed an ideal flow column showing how the velocity increased as the fluid was carried up the column, hut did not give any figures as to the velocity. It would be well to take that sort of a diagram to establish an ideal velocity at the lower or intake end, and then calculate the velocity from expansion of the gas as it goes up. It may be that the, ideal intake velocity would vary, depending on the depth of the well, the quantity of liquid to be handled or the pressure which it may be desired to hold. The subject is one that might be worth much research.

Jan 1, 1928

By Martin Weinstein

A technique is described for preparing finegrained lead telluride by ultrasonic agitation of a solidifying melt. Material prepared by this technique is dense and chemically homogeneous. N-type PbTe, containing 0.03 mole pct PbIz, has been made and its thermoelecCric Properties have been measured as a function of temperature. For comparison, the properties of similarly doped PbTe made by cold pressing and sintering, and by extrusion, have also been measured. The ultrasonically prepared material compares favorably with the others in its thermoelectric-efficiency factor. Comparison of compressive-flow curves for the three kinds of PbTe show that the ulhasonically prepared material has much superior ductility. The cleavage strength of the ultrasonic material is related to the grain size, D, by the Petch relation:Extrapolation to infinite grain diameter yields a fracture strength of 5000 psi for single-crystal PbTe. WHEN metals and semiconductors solidify in a mold they normally assume one of three cast structures illustrated in Fig. 1.' Solidification in a casting starts at the mold walls where a large number of fine crystals of random orientation can be nucleated to form the chill zone. Because of the anisot-ropy of the growth rate, those crystals whose direction of maximum linear growth is parallel to that of the heat flow grow faster and crowd out the crystals of less favorable orientation. A second zone, having a preferred orientation, called the columnar zone, thus forms adjacent to the chill zone. The speed of growth of the columnar grains will depend, in the case of limited undercooling of the melt, on the rate at which heat can be abstracted. The columnar zone can extend to the center of the casting, Fig. l(a), but it is frequently followed, in solid-solution alloys, by another zone of equiaxed randomly oriented grains in the central portion of the casting, Fig. l(b). The equiaxed structure in Fig. l(c) represents the completely grain-refined case where the equiaxed grain size is small. The third type of structure is the most desirable because it imparts a somewhat higher strength for all except high-temperature applications, it reduces segregation of the doping constituent, and it reduces the possibility of hot tearing (the separation of grains due to the melting of a low-melting point constituent in the grain boundaries). In order to obtain fine-grained castings, the nu-cleation frequency must be increased and grain growth must be restricted. Various techniques have been employed for obtaining this end, namely: rapid cooling, vibration, and inoculation of the melt. The success of these techniques depends upon the characteristics of the metal species and on factors controlled by heat transfer through the crucible walls. Recent studies2" have shown that the application of ultrasonic energy to the solidifying ingot is an extremely powerful tool in the improvement of the crystalline structure of metallic castings. Both the mechanical properties and homogeneity of the ingots are improved. Ultrasonic oscillations may affect the crystallization process by 1) permitting subcritical nuclei to agglomerate and thus form nuclei of sufficient size to cause crystallization, 2) changing the state of surface adsorption of various catalysts found in the liquid melt, 3) breaking pieces of solid from the solidified surface near the supercooled region thereby increasing the number of possible nuclei, 4) causing temperature fluctuations to occur in certain parts of the melt thereby increasing the supercooling at specific points in the liquid, and 5) decreasing the critical nucleus size by increasing the pressure at specific points in the melt.' Various investigators have concluded that the effectiveness of the ultrasonic oscillations results from cavitation which disrupts the growing solid-liquid interface The present paper describes the application of ultrasonic oscillations to the crystallization of the semiconductor N-type PbTe. The purpose of this study is to prepare crystalline

Jan 1, 1964

[United Engineering Society ARTHUR S. DWIGHT J, VIPOND DAVIES J, V, N. DORR Engineering Societies Library Board SYDNEY H. BALL ALEXANDER C, HUMPHREYS GEORGE C, STONE JOHN H, JANEWAY Engineering Foundation Board H. M. BOYLSTON J. VIPOND DAVIES GALEN H, CLEVENGER Society for Promotion of Engineering Education WILLIAM KELLY ALLEN H. ROGERS]

Jan 1, 1928

By D. W. McGlashan, K. N. Mcleod

IN the use of free bubbles with precise temperature control and continuous pH measurement, the contact angle apparatus differs from all previous equipment. Experimental procedures differ sharply from the captive bubble method1,2 of introducing the gaseous phase in the three-phase system. When freed from the tube and captured by a solid surface, a bubble more closely conforms to the spherical ideal set up by the usual mathematical analysis of surface free energy or surface tensional relationships of the forces involved. The assembled equipment, Fig. 1, departs from the usual contact angle apparatus in providing: 1) water circulation for fixing temperature, 2) instruments to measure and record pH during testing, and 3) a system for producing and using free bubbles. The apparatus allows testing over a broad range of closely controlled conditions, and the use of free bubbles gives contact angles independent of operator manipulation, which was unavoidable in the older captive bubble method. A bubble released below the specimen rises through the liquid and contacts the mineral. If the mineral is gas-avid the bubble adheres, developing a finite contact angle. Reaction cells (1), 2x33/8x5 3/16 in. ID, are of pyrex glass 5 mm thick. To prevent optical distortion, the sides are optical flats and are planed parallel to within five wave lengths of light over the entire surface. Special cement is required to withstand chemical attack and thermal shock. The cell is placed in a thermal jacket (2) made of welded aluminum. A water seal for the optical ports is made by using O-rings tightened against the flats of the cell by fine-threaded and adjustable ports, Fig. 2. In-flow water is discharged downward from a manifold located near the bottom of the cell jacket. Water overflows the weirs at each end of the cell jacket, discharging from both sides to a collecting manifold (24). A hose (26) leads the overflow water to the thermal-conditioner well (4), which is recessed to accommodate a reaction cell and two beakers (150 ml). Both the thermal jacket and the thermal-conditioner well are insulated to minimize the effects of temperature differentials. Water, discharging from the thermal-conditioner well, returns to a thermostat bath and pump (3), from which it is pumped to the thermal jacket. The thermostat bath permits temperatures to be adjusted from 1" or 2°C to 80°C and will maintain the selected temperature within 0.2ºC. An electrode support (22) groups the four electrodes (8) so that they fit conveniently into the reaction cell, Fig. 2. This assembly holds the glass electrode, the calomel electrode, the temperature-

Jan 1, 1957

By Omar A. Muhtadi

Experimental statistical designs were used at Zortman Mining Company's, Zortman, Montana, heap-leach operation to establish functional relationships between key operating parameters and gold/silver recoveries. Zinc feed rate, lead feed rate, and vacuum (CFM/gpm) account for 64% and 67% of the attainable gold and silver recoveries, respectively. Surface response graphs of the resulting polynomials were plotted. These graphs were used to optimize Zortman's Merrill-Crowe precipitation process.

Jan 1, 1984

By E. N. Pugh, J. V. Craig

WhILE it has been established that well-defined microhardness impressions can be produced in germanium by room-temperature indentation,1-3 the role of dislocations in the process is the subject of continuing discussion.4-7 Recently, Carroll and ~anaka'

Jan 1, 1969

Jan 1, 1930

[NORTH AMERICA UNITED STATES ALABAMA AUBURN Sturm & O'Brien, Consult. Engrs. °Sturm, Rolland G. BESSEMER Granger, W. C. BIRMINGHAM Air Reduction Sales Crockett, John M. Amer. Cast Iron Pipe Co. Carter, Sam F., Jr. Donoho, C. K. Anderson Elec. Corp. Davis, Moss V. J. B. Clow & Sons Neptune, Maurice D. Connors Steel Div. °Sandelin, Robert W. Hayes Aircraft Corp. Ricketts, W. E., Jr. Willhelm, A. Clyde, Jr. McWaine Cast Iron King, O. H. Worthington, B. W. Shook & Fletcher Sup. Co. Gearhart, Thomas A. Southern Res. Inst. Dismukes, Edward B., Wheelahan, Edmund J. Thomas Foys Miller, Ralph M. Union Carbide Metals, Co. Brandler, Edgar A. U. S. Pipe & Fdry. Co. Clay, Donald H. Unaffiliated Berg, H. A. Caldwell, H. A. Gilmer, H. U. Harris, Thomas H. Templeton, J. B.]

Jan 1, 1961

By Charles L. Elliot

Data on worldwide geophysical activity in application to mining exploration programs is collected annually as part of a continuing service to the mining and petroleum industries. The data for mining geophysical activity in 1966 has been made available to SME by the Society of Exploration Geophysicists. This data is based on 288 voluntary responses for a return of 59% to 487 questionnaires that were circulated among worldwide mining companies, universities, and government institutions that conduct or utilize mining geophysical surveys or carry out allied research efforts. This data is herein published in condensed form with the permission of the SEG.

Jan 11, 1967

By C. F. Weinaug

In recent years, several methods have been proposed for correlation of physical properties and behavior of hydrocarbon systems. These correlations were found to be unsatis. factory for predicting differential gas liberation and shrinkage data now obtained experimentally. To achieve the desired accuracy, methods were developed to adjust the correlations with two experimental pieces of data. The required data are the saturation pressure at reservoir temperature and the specific volume or density at these conditions. The saturation pressure is used to adjust the vapor-liquid equilibrium-ratio correlations. The density measurement is used to determine the apparent density of liquid methane. With these adjustments, differential gas liberation and shrinkage are predicted within the experimental error. EQUILIBRIUM RATIOS Equilibrium ratios published by the National Gas Assn. of America' were used as a basis for the calculation. The convergence pressure for the sample was determined by using a hypothetical binary system, with methane as one component and the remainder of the system lumped together to form the other component. For the critical temperature of the heavy constituent, the weight average of the critical temperatures of the ethane and heavier components was used. The correlation of pseudo-critical temperature, density and molecular weight of Matthews, Roland and Katzl was used in this calculation for the hexane and heavier fractions. Points for the critical properties of methane and the hypothetical heavy constituent were placed on a chart of the critical loci of hydrocarbon systems. A critical loci for the hypothetical binary system was drawn, and the critical pressure of this system was determined at the reservoir temperature. This critical pressure became the convergence pressure for which equilibrium ratios were read from the NGAA4 charts. The NGAA equilibrium constants for C, through C, were used for the C,; through C, fractions since they were separated on the bases of normal paraffin boiling points. The correlation of Hoffman, Crump and Hocott5 as used to estimate the equilibrium constant for the C fraction. The NGAA eauilibrium-ratio charts are based primarily on paraffin systems and have to be corrected for the presence of naphthenes and aromatics. The correlations in the literature proved too unsatisfactory for determining these corrections. EXperimental data, the saturation pressure, is used with the correlation of Soloman2 to make this adjustment. The correction factors of Soloman were cross-plotted so that the factors for ethane and heavier components were made a function of the factor for methane. a2 = 0.7927 at + 0.1646 .........(1) where a, = correction coefficient for for methane NGAA equilibrium ratio, and a2t = correction coefficient for ethane and heavier NGAA equilibrium ratios. This equation and the equation for the bubble point are solved simultaneously for the correction coefficients. The bubble-point equation is anKnXn = 1.0 . . . . (2) The equilibrium constant for the saturation pressure at reservoir temperature is used. This procedure not only corrects for the relative volatility between components, but also assures that the results will be directly related to the experimental saturation pressure. METHANE DENSITY After determining a set of equilibrium ratios, the apparent density of condensed methane at 60°F and 14.7 psia was estimated. This was found to be necessary because the correlations of Standing3 ere found to be unsatisfactory. The law of additive volumes was employed to make this calculation.

By Raynor Linzey, Karl M. Busen

The formation of thin films of silicon oxide by anodic oxidation of silicon and the subsequent removal of these films by an etch is a process often used for the evaluation of concentration distributions Profiles) in silicon layers by the differential sheet conductance method. The accuracy of the resulting profile is very strongly influenced by the uniformity of the thickness of the reacted silicon. Normally, it would be expected that for a constant number of coulombs passed the thickness would be the same from oxidation to oxidation. Investigations show that in certain electrolytes, for a given number of coulombs passed through an n-type silicon sample, the thickness of the reacted silicon increased with increasing resistivity. Even for the same resistivity the thickness varied sometimes by a factor of 1.5. When an electrolyte was used which consisted of 10 pct water by volume in ethylene glycol with 4.0 g KNO per 1000 ml of solution, anodiza-tion at 5 ma per sq cm led to satisfying results. Short-time anodizations gave oxide layers of a higher apparent density than those experienced from thermally gown silicon oxides. THE functioning and the electrical characteristics of semiconductor devices are based upon the incorporation of "impurities" into a single-crystalline body of suitable material and on the concentration distribution (profile) of this impurity. The incorporation can be achieved by well-known processes as, for example, by diffusion, epitaxial growth, alloying, or ion implantation. Often the profile resulting from these processes is not known. A powerful tool to learn about a concentration distribution is given by the method of differential sheet conductance which employs successive four-probe measurements on a layer subjected to stepwise removal of thin sublayers. Differential sheet conductance vs position (or penetration depth) of a sublayer is plotted and a smooth curve is drawn through the data. From this curve the profile is then calculated. When the semiconductor material is silicon, the sublayers are removed suitably by anodic oxidation of the silicon and subsequent dissolving of the formed silicon oxide by an etch. The accuracy of the resulting profile is very strongly influenced by the uniformity of the sublayer thickness. Normally, it would be expected that, for a constant number of coulombs passed, the thickness would be constant from oxidation to oxidation. Investigations showed that for sublayers several hundred angstroms thick the reproducibility can be rather poor. Therefore, efforts were made to obtain a reliable technique for uniform removal. The present paper describes such a technique and certain phenomena which were encountered during the investigations. APPARATUS AND TECHNIQUE The first report on the investigation of concentration distributions, where for differential sheet conductance measurements thin silicon sublayers were removed from a diffused layer by anodic oxidation, was given by Tannenbaum. The author reports the removal of sublayers which for the most part were 400 thick. More advanced device designs now require much narrower layers. When it was tried in these laboratories to determine profiles within such layers, difficulties were encountered with respect to sublayers which by necessity had to be thinner than the ones reported by Tannenbaum. The apparatus used for the investigations is sketched in Fig. 1. Two cylindrical containers connected by a wide tube are filled with an electrolyte. The left container receives the cathode whereas the right container is closed at the bottom end by a sample support consisting of a Teflon base and a copper pedestal. The silicon sample (1 by 1 cm) is mounted to the pedestal embedded flush in the Teflon base using silver paint (Degussa) for electrical contact. Pyseal is applied to the edges of the sample to protect the copper pedestal from the electrolyte. The base is mounted to the container using a water-tight silicon rubber gasket. Fig. 2 gives a view of the sample support. The copper pedestal is connected to the positive side of a power supply operating at a constant current output (Kepco Model ABC 425M). The electrolyte which has been reported by Duffek et al. consisted of either 2 or 10 pct water by volume in ethylene glycol and 4.0 g KNO3 in 1000-ml solution. The electrolyte is best prepared

Jan 1, 1967

By H. Buttner, F. H. Udin, J. Wulff

GRAIN boundaries, the interface between adjacent crystals differing only in respective orientation, have been the object of much experimental and moderate theoretical attention for many years. The earlier experimental work was primarily concerned with the effect that grain boundaries have on the physical behavior of metals, while the basic nature of the boundaries themselves drew only secondary attention. A complete turnabout has been witnessed in more recent years, however, as researchers are now undertaking investigations bearing as directly as possible on the character and physical properties of the grain boundary. Quite comprehensive reviews of the past literature on the subject of grain boundaries have been reported on numerous occasions by various authors, and together these references represent a thorough coverage.'-? It becomes evident in these reviews and other papers"" that the properties of grain boundaries can be explained by regarding a grain boundary as a crystalline region of transition between two unmatched grains. Studies show that grain boundaries have a definite interfacial energy. By measuring the geometry about a point where three interfaces meet in equilibrium, the energy of any two boundaries can be measured with respect to the third. If the absolute interfacial energy of one boundary is known, the absolute energy of the other two boundaries can be calculated. This apparently holds true for any system of phases and interfaces.""25 Most studies have been carried out on solid-solid or liquid-solid systems, or systems of both. However, if about the point of intersection one phase is vapor and the other two are disoriented grains, then two interfaces are surfaces, and one is a grain boundary. Investigations leading to relative grain boundary energy for this particular system have been made by Fullman,23 Greenough and King," and Bailey and Watkins." Herring" treats the system mathematically and arrives at an equation, which appears as Eq. 1, in a form consistent with the reference angles indicated in Fig. 1, ( d?1 ?n = x sina + cosa ( ------- 2 ?2 Sinß da + C0Sß (d?2/d As the system of interfaces comes to equilibrium, a groove of angle appears at the intersection of the grain boundary with the surface, an effect first observed by Rosenhain and Humfrey." Eq. 1 is essentially a summation of the vertical components in Fig. 1 set equal to zero, where ?1 and ?2 are surface tension vectors lying along the side of the groove at point 0 in the groove root. The differential vectors represent the forces tending to rotate the surface into a position that will expose a crystal cleavage surface of lowest energy. Chalmers, King, and Shuttleworth- simplify Eq. 1 by assuming the differential vectors equal to zero, ?1 = ?2= ?Surface and arrive at the following equation: ?B = 2?s cos [2] Greenough and King24 use Eq. 2 for determining the grain boundary energy of silver using prepared bi-crystals of known orientation. Bailey and Watkins25 have done the same for copper, as did Chalmers and others on lead. These authors report the grain boundary values as ratios relative to the surface energy. In the above work, the orientation of grains forming the grain boundary in all cases was controlled so

Jan 1, 1954

By R. Hogg, F. F. Aplan, P. B. Bradley, M. F. Placha

Particle size distributions of the solids fraction in typical coal preparation plant black water have been evaluated. The carbonaceous and mineral fractions were found to have distinctly different size distributions: the mineral matter being significantly finer than the carbonaceous material in all cases. Based on analyses of 13 samples obtained from the Appalachian, mid-continent and western regions of the US, it was found that, on the average, 83% of the mineral particles but only 41 % of the coal particles were finer than 44 pm (325 mesh). Typically, the size distributions of the mineral matter fraction tend to be bimodal, probably due to the presence of relatively coarse quartz, calcite, pyrite, etc., together with much finer clay particles.

Jan 1, 1981

By Benjamin Tillson

The hammer drill rightly receives the credit for having made the one-man drill possible, and so many economies seem possible through the proper application of :different types of hammer drills to various mining, quarrying, and, excavating operations, that an indication of the economies effected by the New Jersey Zinc Co. at its Franklin mines may be of pertinent interest. When this company commenced its trials of hammer drills in 1907, these tools had not I been developed to one-fourth the capacity and refinement which they have at present. At that time it was frequently stated that such a small tool, drilling holes of less diameter than the reciprocating rock drill, could not drill enough holes in a shift to permit the placing of sufficient explosive to break a tonnage of ore comparable with that produced by the"' rock drills;" that the placing of small holes inclined upward, at angles steeper than 40° above the horizontal, could not be expected to produce results equal to the large flat, wet or dry, holes in the breasted back of an overhand stope, and would only shatter the ground so as to make the back unsafe. In' spite of these adverse opinions, the hammer drills first showed their superiority over both heavy and light reciprocating drills in raising and in stoping, and then in drifting and quarry work. As a result, all of the reciprocating drills at the Franklin mines were scrapped, three years ago, all of the mining work being accomplished with increased efficiency, as shown in detail in this article. With the advent of the hammer drill in this property, it was considered advisable to make comparative tests of all the tools accessible, and it has since been the policy to investigate the merits of any advance of the drilling art in order to get the maximum amount of work from the tools. The necessity of devising some means of standardizing drill tests, and of measuring the consumption of compressed air as well as the drilling speed, was early realized.

Jan 2, 1915

By C. R. Clark, G. Swift, D. S. Roberts

The purpose of this investigation was to measure PVT behavior of various types and combinations of heavy hydrocarbon components from the paraffinic, naphthenic and aromatic classes where the relative proportions Of the various components were selected to approximate those of natural gas or gas condensate systems. Synthetic mixtures were used so that the compositions Of the various components could be measured accurately. n-Heptane, methylcyclohexane and methylbenzene were used to represent the paraffinic, naphthenic and aromatic components of the heavy fraction. In the mixtures studied, the heavy fraction composition was held constant at O. O5-mole lraction, the balance being methane except for one mixture where 0.10-mo1e fraction of an intermediate component, propane, was added. The PVT data for the mixtures were determined in a variable-volume, constant-mass apparatus at psuedo-reducedtemperatures from 1.84 to 2.00, over a pseudo-reduced pressure range from 2.3 to 12.0. The experimental results showed that, regardless of the type of heavy material (paraffinic, naphthenic, aromatic, or combinations thereof) mixed with methane or methane and propane, the compressibility factors at equal values of pseudo-reduced temperature and pressure varied by less than 2.2 percent. INTRODUCTION PVT data is used for natural gas and gas condensate fluids in determining reserves of reservoirs and performance of wells, in metering produced fluids, and in recombining samples for laboratory studies. While there are vast amounts of PVT data reported for natural gas and gas condensate systems from which useful correlations have been developed, ' the compositional analyses for these systems and the resultant correlations typically were made with components analyzed through some arbitrary carbon number, usually C6, with the residue reported as a lumped "heavy" fraction. The heavy fraction was stoichiometrically recombined on the basis of an apparent molecular weight to give the final compositional analysis. It is virtually impossible to make a systematic analysis of the effect that variation of the relative amounts of paraffinic, naphthenic and aromatic constituents of the heavy fraction of natural systems might have on PVT behavior. Because there is considerable latitude in the relative amounts of these constituents, one speaks of crudes or condensate liquids as being "paraffin base", etc. It is of interest to determine if changes in the relative amounts of these three types of hydrocarbons in the heavy fraction cause significant changes in PVT behavior. If so, steps should be taken to describe better the nature of the heavy fraction in PVT correlations. If not, more confidence can be placed in the correlations presently employed. DESIGN OF THE EXPERIMENTAL INVESTIGATION We attempted to determine if changes in the base of the heavy fraction would cause significant changes in the PVT behavior of gas or gas condensate fluids. Synthetic mixtures were used to enable us to systematically vary the base of the heavy fraction and to analyze accurately the fluids. We found that the heavy fraction of naturally occurring condensate systems seldom exceeds 0.05-mole fraction. Thus, the mole fraction of the heavy fraction in the synthetic systems studied was set arbitrarily at 0.05, to maximize whatever deviations in PVT behavior that might occur. Further, we judged that since the C7 hydrocarbons normally are present in greater quantities than higher carbon number hydrocarbons in naturally occurring systems, the use of n-heptane, methyl cyclohexane, and methylbenzene to represent the paraffinic, naphthenic, and aromatic species in the heavy fraction would be most appropriate. Finally, to enable us to compare our

Jan 1, 1970

By John Chipman, Eric R. Jette, O. B. Ellis

In the study of the chemical reactions orcurring in the open-hearth furnace, it is frequently assumed that a condition of equilibrium between slag and metal is attained. In order to test this assumption it is necessary to have dependable operating data as well as an exact knowledge of the equilibrium state. Considerable progress has already been made in the study of slag-metal equilibria, notably in the earlier work of Hertyl and of Oberhoffer and Schenck2 and in the more recent researches of Krings and Schack-mann3 and of Koerber and Oelsen.4 None of these investigators, however, have employed basic slags comparable to those encountered in basic open-hearth practice, so that up to the present time our only information regarding the equilibria of these slags is based upon observations drawn from steelmaking practice in which there is little assurance that actual equilibrium was attained. The original plan of this investigation was to secure simultaneous slag and metal samples at intervals during the making of an open-hearth heat, recording the heat history in detail and obtaining complete allalyses of slag and metal, then to bring these slag samples into equilibrium with liquid iron in the laboratory induction furnace and thus to determine directly whether or not the observed relationships in the open hearth represent conditions approaching equilibrium. This plan was only partly successful. While slags were obtained from the open hearth under satisfactorily recorded conditions and these were re-melted in the laboratory under equilibrium conditions, changes in slag composition, which accompanied the remelting operation, were so great that the final slag from the induction furnace bore little resemblance to its open-hearth parent and the direct comparison was therefore abnndoned. The results, however, lie within a range of slag composition that is of interest in the making of low-carbon steel. As far as we are aware, they represent the first published laboratory study of equilibria involving slags that contain all the con stituents of basic open-hearth slag. Experimental Heats The first set of measurements on slag-metal equilibrium was made in the Research Laboratories of the American Rolling Mill Co, at Middletown, Ohio. This will be known as series A. The second set was made in the Metallurgical Rescarch Laboratories at Massachusetts Institute of Techology, and will be referred to as series B. Series A.—The induction furnace used has been described. Approximately I kg. of a special ingot iron containing less than

Jan 1, 1941

By H. B. Pulsifer

THIS paper outlines a method for rapid production of flat, granular surfaces on many of the medium hard- alloys. Grinding wheels and fabrics on wheels are not used; the purpose is accomplished by rubbing on emery papers and on fine abrasives heaped on hand boards. The advantages of chromic acid in the solutions for etching nickel and copper alloys are explained. Steels may require an additional step in the mechanical smoothing owing to the lack of an ideal etchant. Chloric acid is a. rapid etchant for steel. Thirty-six photomicrographs illustrate the steps in smoothing and the clearness with which structures can be rapidly exposed. New structures in low-carbon steels are announced. After a little practice, many materials can be finished within two or three minutes. CUPRONICKELS In the previous papers on the metallography of copper and magnesium which the author has presented to this Institute there has been an attempt to demonstrate the advantages of minimizing the mechanical work of surfacing and depending more on chemical means; the present paper continues the research into a still wider field. It is obvious that the success of a chemical method for smoothing and etching depends almost entirely on the use of a suitable reagent. The etchant must remove the surface granulations and outline the structures. A very special type of reaction between reagent and metal must be displayed. Promiscuous corrosion or the intensification of the attack about local couples -formed by impurities or components must not be in evidence. There are several reagents that etch highly polished nickel and copper alloys very well. Acidified ferric chloride solutions, concentrated and dilute nitric acid solutions, and nitric and acetic acids in acetone have -been used to good advantage for the purpose. However, if they are expected to etch rather deeply-that is, smooth as well as characterize-the results may be far from satisfactory.

Jan 1, 1928