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By P. J. Jorgensen, J. H. Westbrook

The anomalous indentation creep of nonmetallic solids is shown to be due to the presence of adsorbed water. Although a specific mechanism is not proposed, it is suggested that the water may be present in two chemically adsorbed states. DEPENDENCE of the indentation hardness of solids on the time of load application was first studied systematically by Hargreaves1 in a study of lead and certain low-melting alloys. This technique has become known as indentation creep and has been exploited particularly by underwood and by Mulhearn and Tabor3 as well as by others.4°7 For metals good correlations have been found between the time dependence of hardness over several orders of magnitude in the seconds range and creep parameters from conventional tests at the same temperature where creep strains were measured over hundreds or thousands of hours. However, Walker and Demer8 and Mitsche and Onitsch9 observed extensive indentation creep at room temperature (particularly for light loads) in certain minerals and in materials such as lithium fluoride and magnesium oxide for which conventional creep is ordinarily not observable unless the testing temperature is at a very much higher fraction of the melting point. Normal behavior was observed' for metals such as copper, i.e., negligible time-dependent flow during room-temperature indentation. Walker and Demer attempted to find some distinctive difference in the surface deformation markings about indentations in the anomalously behaving materials at short and very long indentation times. No significant differences were observed. Increased duration of loading was found, however, to result in an increase in the length of glide of edge-dislocation loops extending into the interior of the crystal. Jorgensen and Westbrook,10 in a recent study of

Jan 1, 1965

By Arthur C. Spencer

In extension of a suggestion already made to account for certain features observed in the Juneau gold-belt in southeastern Alaska,' it is the object of the present paper to indicate in detail certain conditions in which deformation of rocks under their own weight might lead to the production of fractures in which veins could be deposited. A direct, uniformly-distributed pressure of sufficient intensity, applied to an elastic brittle mass offering strung resistance to deformation, produces rupture. In a material of ideal properties the surfaces of rupture under such pressure would be shearing planes inclined at 45' to the line of force, unless there be preliminary deformation, in which case this angle would be greater than 45. This general conclusion, resting upon analytical mechanics, is completely supported by the results obtained by DaubrBe2 in experiments upon the deformation of wax and resin prisms under compression. Let us then first consider one of Daubree's diagrams. In the case illustrated in Fig. 1, four sets of fractures in two approximately right-angled pairs (that is to say, in conjugate sets) were produced by endwise compression of a square cross-sectioned prism. These fractures cut the axis of compression at approximately equal angles, not varying greatly from 45o. The location of the four sets of fractures is obviously determined by the shape of the prism, since the material in each corner acts in a way as a buttress, permitting the bulging to take place most readily on the sides. By limiting the directions in which bulging may take place, results of a more simple nature could be obtained. Take, for instance, a square prism, and place it between two fixed and

Jan 1, 1906

By J. F. Kemp

PAGE I. Introduction,.......269 11. Topogmphical Features,.....270 III. Geological Relations of the Mineralized Area,.272 1. Structural Features,.....272 2. Occurrence of the Copper,....274 3. Granite-Contacts,.......274 IV. Descriptions of the Rocks,.....274 1. Granite,........274 2. Limestone,.......276 3. Porphyritic Eruptions,.....278 (a) Quartz-Porphyry,.....278 (b) Trachyte-Porphyry,.....280 V. Contact Phenomena,......285 1. Comparative Immunity of the Limestone, . 285 2. Contact Phenomena in the Quartz-Porphyry,.... 285 3. The Form and Distribution of the Ore-Bodies,290 VI. Method of Deposition,......293 I. Introduction. The White Knob copper-deposits are situated about three miles south of Mackay, on the Salmon River branch of the Oregon Short Line Railroad, in Custer county, Idaho. An outline-map of this district is given in Fig. 1. The deposits have been known and spasmodically worked for many years, and a total of over 3.5 miles of tunnels, shafts and other workings has been driven with a view to their development. These extensive excavations have exposed the deposits sufficiently to permit a careful geological examination. The peculiar features which give special interest to this paper are the branching, tree-like form of the ore-bodies; the absence of zones of secondary enrichment in the partly oxidized pyritic deposits, and the fact that while the deposits are associated in a general way with the contact of an eruptive rock with limeetone, which it penetrates, the garnetization has taken place not in the limestone, as is the usual case, but in the igneous

Jan 1, 1908

By J. McLaren Forbes

Geologists and engineers in charge of diamond drilling often have no practical experience in the work, yet they must direct the drillers. In discussing some of the problems that arise, the author of this paper has tried to remember the things he did not know about diamond drilling when he first came in contact with that work. The basic reason for most diamond-drill holes is to obtain information. The more thorough the understanding of the geological and engineering problems involved, the greater will be the benefit derived from a drilling program. One of the best methods to ensure some thinking before drilling is to record on the permanent drill log, before the hole is collared, the reasons for the work and the information desired from that particular hole. When the hole is finished, the information obtained should be recorded. Driller The choice of a diamond driller is very important. If no experienced driller is available, a competent miner who has a sense of responsibility and better than average mechanical ingenuity can do the work. The best answer to most practical drilling problems, from the standpoint of the person in charge of the drilling program, is the service of experienced diamond drillers or drilling firms. Equipment Drilling equipment should be adequate to put down the longest hole desired and handle the toughest ground encountered. The type of bit used depends upon the ground drilled. Experimenting with various bits and careful study of footage records are the best means of determining which to use. Under ordinary circumstances it is best to drill using an EX barrel when possible. The length of rod and core barrels that can be used depends on the size of the drill station. Also, the length of core barrel depends on the way the ground cores. In good ground as much core will be recovered with a 10-ft. barrel as with a shorter one, and with considerable saving of drilling time. A water pump is needed if the hole is so deep that the water pressure is not strong enough to wash out the cuttings, or if it is drilled at an angle that prevents full force of the water pressure. Instructions For an Inexperienced Driller 1. Never run a bit too long a time. When a bit seems to be "good for one more run," discard it. 2. Always let the rods down on bottom easily. Protect the bit from sudden shock. 3. Start the drilling slowly and easily. Do not put pressure on the bit too fast. Diamonds can break. 4. Be sure the water pressure is strong enough to clear the bit, but do not use more water than is needed, as it may wash away the core. Usually, if no core is recovered the hole is a total loss. 5. When dry-blocking, do not run without water longer than necessary as the bit may burn. 6. Be sure the rods are well caulked and tightly screwed together. If not well caulked they will lose water, and if not

Jan 1, 1946

By V. F. Hollister

Although it is apparent that porphyry copper deposits may have formed in the Andean orogen from Permian time onward, commercial deposits thus far developed appear to have Cenozoic ages only. Following Chilean usage, the porphyry deposits are divided into either (1) a stockwork or (2) a tourmaline breccia model. As indicated by evidence cited in the paper, stockwork-type deposits tend to be related to major strike-slip structures which may be either transcurrent or transverse faults related to plate movements, while the tourmaline breccia type may more frequently form independently of regional faults. Stockwork types may be conjugate fractures that intersect and ramify as a network of veins and veinlets, cutting altered rock, and genetically related to a major regional fault, or in other cases they may reflect the intersection of two large fault structures. Circular fracture patterns may more rarely occur in stockwork deposits in response to a specific intrusion. Tourmaline breccia types are characterized by circular and radial fractures genetically connected in some way with touramline breccia pipe development or an intrusive piercement that preceded it. Each structural model contains mineralized intrusions which have a close time-space relationship to ore, and in each model mineral paragenesis is similar, regardless of age or location in the plate. Also, each model contains the same type of alteration halos (phyllic, argillic, propylitic) as are developed in intrusive centers in porphyry copper deposits found in North America. The potassic zone is exposed best in the older deposits. Examples of each type of deposit are illustrated, demonstrating the feature evolved.

Jan 1, 1975

By Carl R. Christiansen

Since the first pay hole in Missouri's "New Lead Belt" was drilled in 1955, this district has become one of the world's leading sources of lead. The belt extends from north of Viburnum in a southerly direction to near Eminence, a distance of about 35 miles. The St. Joseph Lead Company was the discoverer and first to develop new mines in the Viburnum area. Since the discovery of the New Lead Belt, many companies have engaged in exploration programs and several major companies have become active in development of new mines. These include Cominco American, Inc., which operates a joint venture with Dresser Industries; Ozark Lead Company, a subsidiary of Kennecott Copper Company; and Missouri Lead Operating Company, a joint venture of Arnax and Homestake. St. Joseph Lead Company, with over 100 years of experience in the Old Lead Belt, has served as a leader in development of equipment and mining techniques, making its properties some of the most efficient mining operations in the world. The new producers give the district the benefit of fresh viewpoints, as their engineers are mostly from outside of Missouri and their previous experience has been considerably different from conventional lead belt practices. While all operations are similar in that they are room-and-pillar, the diverse experience of the operators has produced a group of mines that employ a variety of equipment and mining techniques to give increased efficiency

Jan 1, 1970

By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION in pure gold has been studied by Sagrubsky,1 McKay,2 Gatos and coworkers,3,4 and Okkerse.5 Sagrubsky used a sectioning technique but reported results far lower than any of the others. The work seems to be carefully done, and it appears that a factor of 60 must have been omitted in his calculations or the units misstated by an equivalent amount. McKay used a surface activity method, and Gatos and Kurtz, following Gatos and Azzam, applied autoradiography to the measurement of activity on an oblique section through the diffusion zone. These two investigations agree well with each other but give results below those reported here. Okkerse employed a very careful sectioning technique. Chemical interdiffusion in Au-Ag alloys has been measured under several concentration conditions. Average values of the diffusion coefficient for the range of 0 to 18 atomic pct Au were obtained by Braune.6 since the diffusion coefficient probably varies markedly over this range, the values may not be too useful. Also, a plot of these data suggests that grain boundary contributions may have been appreciable at the lowest temperature employed. Ebert and Trommsdorf7 give average values for 0 to 9 atomic pct Ag, and Johnson8 reports average values for 45 to 55 atomic pct Au. Johnson also measured silver and gold self-diffusion coefficients in 49.2 atomic pct Au alloys, and self-diffusion in pure silver. The self-diffusion of gold in pure silver has been determined by Jaumot and Sawatsky.10 Other measurements which do not cover a range of temperature or are of low precision are not mentioned in this account since a review by Kubaschewski is available." This contribution reports diffusion coefficients for self-diffusion in gold, self-diffusion of gold in Au-Ag alloys, and chemical diffusion in Au-Ag alloys. Although it had been intended to obtain silver self-diffusion data in the alloys it now appears unlikely that these measurements can be done soon, so a table has been worked out for a self-consistent scheme of diffusion coefficients which should not be too far from the true values. Experimental Details Experiments on pure metals were conducted using fine gold of 99.99+ pct Au and silver of the same purity. Alloys were prepared by melting the two metals together in a graphite crucible in vacuo and allowing the slug to solidify in the crucible. After machining to a cylinder about 0.85 in. diam each slug formed one half of a diffusion couple. Compositions were determined later by analyzing chips taken from the extremities of the diffusion zones. The gold used in the preparation of alloys was sometimes pure gold but was normally either in the form of clean pickled alloy from previous experiments or gold recovered by oxalic acid precipitation from warm aqueous solution. Chips from the various stages of experimentation were dissolved in aqua regia and the solution taken to low bulk, diluted with water, and again taken to low bulk before diluting for the precipitation. This precipitated gold contained a small amount of silver as the only impurity detectable by spectrographic analysis. Disks for use in diffusion couples had opposite plane faces abraded on emery paper as far as zero grit, were annealed for 12 hr at 900°C in argon, and had one face of each disk polished to 000 emery paper. Radioactive gold was plated at about 2 ma per sq cm from a small volume of cyanide solution containing 1 mg of inactive gold as a carrier. Specimens , were freshly abraded on 4/0 emery paper immediately prior to plating. In the case of the active couples disks of a similarly prepared but unplated alloy or pure metal were placed on top and welded to the active disk. With the concentration couples disks of different compositions were welded. Welding was performed after a pressure of 5,000 lb had been applied at

Jan 1, 1958

By F. F. Craig

Many full-scale waterflooding operations are preceded by pilot floods, one purpose of which is to provide an estimate of recoverable oil. A laboratory model study was made to determine the influence of the producing wells' effective productivity on the oil recovery efficiency of single five-spot pilots, as well as single injection well pilot floods. The effective productivity is indicated by the value of Condition Ratio, defined as the actual well productivity to that of on undamaged and non-stimulated, normal-sized well in the same formation. The effects of initial gas satrcration and mubility ratio on recovery eficiency were also investigated in this model study. Model test results skowed that at favorable mobiliry ratios, a five-spot pilot flood can provide a direct quantitative estimate of the recoverable oil in the pilot area. If the pilot producer's Candition Ratio is 2.2 or more, upwards of 90 per cent of the recoverable oil in the pilot area is recovered from the inside producer, regqrdless of the mobility ratio or initial gas saturation. This Condition Ratio can be achieved with preyent fracturing techniques. Model studies also showed that over the range of imposed injection pressure differences and regional pressure gradients normally encountered in field operations, there was no effect on the recovery efficiency of a five-spot pilot waterflood. Model studies of single injection well pilot waterfloods showed that with no initial gas saturation, the total oil recovery at the offset producing wells can indicate the oil recovery possible by full-scale waterflooding. It is essential that the Condition Ratios of the offset wells be above 1.4. If an initial gas saturation exists prior to water injection, the recoverable oil cannot be directly evaluated by a single injection well pilot flood. However, the production per formance of such a flood can be used to provide information on volumetric sweep efficiency. INTRODUCTION Oil reservoirs are conlplex structures and cannot always be fully studied in the laboratory. Therefore, many operators consider it prudent to evaluate a waterflood prospect by means of a pilot flood. Pilot waterfloods generally involve one of two well arrangements: a single five-spot pilot waterflood, involving four injectors and an internal pilot producing well; and a single injection well pilot flood (sometimes called an inverted five-spot pilot) having one injector and four sur- rounding pilot producers. Some pilot floods are composed of multiple five-spot pilot patterns. To yield information applicable to field-wide performance, the pilot must be located in a representative portion of the reservoir. Pilot floods generally are conducted for one or more of the following reasons: (1) to determine whether water could be injected at desirably high rates, (2) to determine whether an oil bank or zone of increased oil saturation is formed by water injection, and (3) to estimate the oil recovery by waterflooding. Many of the early pilot water-floods were conducted for only the first two reasons. As soon as a buzz in oil production was obtained in the pilot, water injection was initiated throughout the entire lease or field. A number ot laboratory studies have been directed toward determining conditions under which a pilot flood could yield a quantitative estimate of the oil recovery possible by full-scale pattern flooding. One of the early studies of single five-spot pilot flooding' showed that well damage to the inside pilot producer could reduce the total amount of oil recovered. In a study of the single injection well pilot flood pattern,' the results indicated that if the model boundaries were no closer than a half-well spacing beyond the pilot pattern, the pilot performance in the laboratory is unaffected by these boundaries. In another study,? he effect of initial gas saturation and mobility ratio on the ratio of production to injection rate for various groupings of five-spot patterns was defined by mathematical and analog methods. In a study4 involving both potentiometric and flow model experiments at a mobiliry ratio of unity, four different pilot patterns were studied. These included a single five-spot, a single injection well pilot, a cluster of four single injection well pilots and six inverted five-spots. In this study the ratio of well diameter to the distance between injection and producing wells was held constant at 1:1000. The effect of the 7 ratio-—the ratio of the pressure drawdown at the producing wells to the pressure build-up at the injection wells on the pilot performance-was studied. The values of 7 ratio ranged from 0 to 0.34. Results showed that both the total oil recovery and the total fluid production from the pilot relative to the cumulative injection increased with increasing values of the 7 ratio. The effect of both the ratio of injection to producing rates and mobility ratio on the oil recovery performance of a liquid-saturated single five-spot pilot flood was studied in a series of flow model tests.5 Rate ratios ranged from one to four, and mobility rates ranged from 0.1 to 10. Resulls of these tests showed that at low rate ratios, the pilot producers may recover up to four times the recover-

Jan 1, 1966

THE developments in construction and operation of the basic open-hearth furnace that have taken place in recent years have placed new emphasis on the vital influence played by regulation and control of the combustion system in both furnace production and furnace life. The several factors influencing flame development, such as regulation of fuel supply, air supply, air preheat, furnace draft, and furnace reversal, must be controlled closely if successful furnace performance is to be accomplished. Rugged instrumentation of distinctive design is required to supply dependable information concerning operating conditions, which is requisite to proper regulation of combustion. This chapter attempts to give a practical discussion of the various features of open-hearth practice and instrumentation related to the efficient heating of the furnace, control of temperature, and protection of the furnace structure from accidental overheating. The appended references will be helpful to readers wanting a more detailed treatment of individual topics. OPEN-HEARTH FUELS The most important open-hearth fuels are listed in Table 4-1 together with their compositions and other data useful for combustion calculations. A detailed discussion of open-hearth fuels is not attempted here, but certain factors peculiar to their application to this type of process are briefly indicated on the following pages. Very often an open-hearth shop is forced by economic factors to use a fuel to which its furnaces are not very well adapted, because the general fuel-allocation scheme for the works as a whole seems to demand it. Often a variable marginal supply of coke-oven gas or tar must be consumed by the open hearth, together with another fuel such as producer gas, natural gas, or oil, to fill out total requirements. Most furnaces employ more than one kind of fuel during their usefu1 life; however, the partial redesign

Jan 1, 1951

By J. E. Castle

THE title of this article is descriptive, but not complete, for psychological evaluation is almost as important as rigid economic evaluation. This refers to those human traits that cause people to be too optimistic about the projects they are sponsoring, to overlook obvious weaknesses, to base decisions on incomplete and inaccurate data, and to gloss over embarrassing problems. Investment of capital in a new industrial mineral project is warranted only after rigorous economic analyses based on unquestionable facts. A plunge into production cannot be justified solely because these minerals have been deposited in the ground and are therefore free. There are no specially favorable economic laws that make the business of industrial minerals more attractive than any other. The factors of supply and demand, marketing, technological changes, taxes, competition, and fluctuating prices apply as much to industrial minerals as to other business enterprises. What is more, industrial minerals are subject to the higher risks that all mining enterprises face.

Jan 6, 1958

By C. E. Sims, C. A. Zapffe

MANY hundreds of publications have appeared during the past 78 years that treat the subject of hydrogen in iron and steel,105 but conclusions regarding the functions of hydrogen in causing some important defects in steel are still unsatisfactory to many; and other hydrogen-caused phenomena yet remain to be identified with this gas. The most widely discussed of these defects is hydrogen embrittlement, but the conception, perhaps the popular one, that embrittlement is due to hydride formation does not conform to the known facts.104 The true identity of hydrogen embrittlement seems instead to lie in a mosaic nature of metal crystals, which is a concept not yet accepted by most metallurgists. A study of hydrogen embrittlement therefore provides new viewpoints in regard to the crystalline substructure of steel. A second widely discussed hydrogen-caused defect is the "flake" or "shatter crack." Although it is generally agreed that the presence of hydrogen is a prerequisite for their appearance, it is also realized that internal stress plays a decisive part. The relationship of hydrogen to internal stress has not been explained very clearly; nor is it always clear what the relationship is between a "flake" and a "snowflake," or between a "fish eye" and a "shatter crack." More importantly, the relationships among hydrogen embrittlement, hydrogen-caused fissures such as "flakes" and the ultramicroscopic structure of steel have scarcely been recognized. The present investigation attempts to provide an explanation for the embrittlement of steel by hydrogen by showing cause for accepting the "block" concept of metal crystals, and then to show how the numerous hydrogen-caused defects are interrelated in the light of this concept. EVIDENCE OF SUBSTRUCTURE IN METAL CRYSTALS It appears that the concept of a crystal as an aggregate of smaller multi-atom units must be accepted in some form if the behavior of metals is to be understood. The abundant literature on the evidence of an ultramicroscopic "mosaic" structure in metals and other crystalline substances suggests that the physicist has provided the metallurgist with an invaluable new insight. The exact picturization that any one physicist provides may be open to question, but the fact that there is some such fundamental substructure seems undeniable. The present work makes no pretense of comprehensively treating the imperfection structure theories. Nor will conclusions be drawn here regarding the exact nature of the substructure of crystals. However, the acceptance of some imperfection theory of fundamental attributes seems so necessary to an understanding of the behavior of hydrogen in steel that the following brief

Jan 1, 1941

By G. R. Mansfield

THE third year of Government exploration for potash by the U. S. Geological Survey and the U. S. Bureau of Mines under the authorization of the act approved June 25, 1926 (Public 424-69th Cong.) is drawing to a close. The results thus far obtained are thought to be sufficiently interesting and satisfactory to justify the presentation of a brief pre¬liminary account of the work. REVIEW OF EARLIER EXPLORATION The general geologic similarity of the Permian basin of Texas and New Mexico to the potash field of Germany had long ago suggested the possibility of the presence of potash salts somewhere in that basin, but petroleum exploration was then making little headway there and the necessary data could not be obtained. The discovery by Udden in 1912 of potash in brine from the Spur well in Dickens County, Texas, was the first direct evidence of its presence. In 1915-17 the U. S. Geological Survey drilled a test well with standard tools at Cliffside near Amarillo, but failed to find potash. Nevertheless, an observer has been kept in the field, at first in cooperation with the Texas Bureau of Economic Geology but since 1922 by the Survey alone, to secure data and samples from oil and gas tests. Since the discovery of oil in Reagan County in 1923 exploration by drilling has been rapidly extended to many parts of western Texas and southeastern New Mexico. The identification of the potash-bearing mineral polyhalite was first announced by the Geological Survey in June, 1921, the material having come from cuttings from the Bryant well in Midland County and the Burns well in Dawson County, Texas. Successive discoveries and announcements of similar purport aroused widespread interest in potash exploration, which culminated in the action by Congress already noted.

Jan 1, 1929

Jan 1, 1902

By L. S. Darken

It has long been recognized that the driving force in an isothermal diffusion process may be regarded as the negative gradient of the chemical potential (partial molal free energy) of the diffusing substance. This equivalence is exactly analogous to the fact that a mechanical force is the negative gradient of the potential energy. Nernstl in 1888 expressed these driving forces in terms of osmotic pressure, which is directly related to the chemical potential and free energy. The relationship between the diffusivity, mobility and activity coefficient of electrolytes in aqueous solution has been developed in great detail by Onsager and FuossZ with results which have recently been confirmed experimentally by Harned and Nuttall. This interpretation of the driving force in isothermal diffusion has been discussed earlier by the author,4,5 who pointed out4 that "for a system of more than two components it.is no longer necessarily true that a given element tends to diffuse toward a region of lower concentration even within a single phase region"; departure from the behavior of an ideal solution may be so great that the concentration gradient and the chemical potential gradient, or activity gradient, may be of different sign, thus giving rise to "up hill" diffusion. Since, in the discussion of that paper,4 some skepti- cism as to the validity of this conclusion was expressed, it seemed desirable to adduce experimental evidence to support it. Evidence of such diffusion in nonmetallic systems has already been reported. For example, it was observed by Hartley" in a series of experiments in which sodium chloride diffused from a saturated solution in about 5 pct acetone in water into a solution virtually free of salt but with essentially the same acetone concentration. Specifically, a wine glass containing crystalline salt and saturated solution was totally immersed in a large glass cylinder containing the acetone-water solution without salt; the difference in specific gravity was such as to prevent convection. Diffusion of salt was accompanied by a marked depletion of acetone in the wine glass; after 3 days the acetone concentration decreased from 5.37 pct at the top of the glass, where the salt concentration was low (0.93 pct), to 1.84 pct at the bottom where the salt concentration was high (21.64 pct). This "uphill" diffusion was found to be such that the partial pressure (activity) of acetone was essentially equalized throughout the system when a steady state gradient of sodium chloride was maintained. In order to demonstrate the existence of such diffusion in metals, a series of four weld-diffusion experiments was made. In these measurements pairs of steel of virtually the same carbon content, but differing markedly in alloy content, were welded at the end and held at 10500 C for about two weeks. Subsequent analysis showed that carbon had diffused so as to produce an inequality

Jan 1, 1949

By T. M. Barry

HOW often have those who make mining a career said that, "mining is different"? This kind of feeling often expresses itself in talking shop with men of other industries. And there is no doubt about it; mining is different. There are different marketing problems, different production problems, and we certainly have different personnel problems, to cite but a few. Mining people have recently been discovering though, that many of their problems are not unique to mining. They are beginning, in fact, to find that many of them are dead ringers for problems that other industries have had to face and solve years ahead of mining.

Jan 6, 1954

By L. S. Darken

In the study of reactions occurring in liquid iron, alone or in contact with a liquid oxide or slag phase, it has been found that the experimental data over a limited range of concentration can in some cases be represented satisfactorily by the simple equilibrium expression where (P) denotes the concentration of a product and (R) the concentration of a reactant in the reaction r1R1 + r2R2 + • • • D P lP1 + P 2P2 + • • • Some of the reactions for which it holds are listed in Table 1. For others, however, the simple equation apparently does not hold. This has been attributed to an improper method of expressing concentration (for instance, weight per cent instead of mol fraction); or it has been supposed that the solutions are not ideal in the sense that the activity of a component is not proportional to its true mol fraction. But it may be that the problem has been oversimplified by neglecting some molecular species actually present; that is, by considering only the ostensible simple components and thus leaving out of account possible compound formation. It is the purpose of the present paper to point out how, in a group of related cases, a reasonable consistent assumption relative to the presence of a compound makes it possible to express the experimental data satisfactorily by the simple equilibrium expression when this compound is taken into account, and to bring into harmony data referring to different reactions in liquid iron. There are several a priori reasons for believing that solutions in liquid iron should not deviate far from ideality, provided that the concentration of solute is not too great and is expressed in proper terms. The factors that commonly lead to nonideality in systems at ordinary temperature— as ionization or the occurrence of polar and nonpolar molecules—are presumably less effective in inetal and in slag systems at high temperature. Again, the type of equation commonly used to express the value of

Jan 1, 1940

By Horace Pops

Isothermal sections in the copper -rich region of the Cu-Si-Zn a1by system have been determined at 8473 760; 6003 and 482°C by means of microscopic examination with confirmatory X-ray diffraction work. The stability of the bee 0 phase decreases both with decreasing temperature and with increasing copper content. The silicon-n&apos;ch 0 phase decomposes upon quenching from high temperatures either by a martensitic or by a "massive" transformation, depending upon the solute content. A two-phase equilibrium is found to exist in the Cu-Si-Zn system between the hep < phase of the Cu-Si system and the bee ß phase of the Cu-Zn system. It is shown that the isothermal limits of the primary solid solution at 760; 6003 and 482°C are in part affected by the intermediate phases which follow them in the ternary system Possible electron-concentration and size effects upon phase boundaries are discussed. ALTHOUGH the mechanical and physical properties of silicon brasses have been measured in great detail, the factors which influence these properties are not well-understood, partly because the knowledge of the phase relationships in the Cu-Si-Zn system is limited. Gould and Ray1 studied the effects of silicon upon the hardness and structure of Cu-15 pet Zn and Cu-40 pet Zn alloys. They proposed an isothermal section at 800°C which was not based upon experimental data, since the binary phase diagrams had not been completely determined. Using Cu-Si-Zn alloys containing approximately 5 wt pet Si, vaders2 determined the boundary, at 750°C, between the copper-rich solid solution and an unidentified second phase. Masing and wallbaum3 examined a vertical section through the ternary diagram in the region between Cu-20 pet Zn and Cu-10 pet Si alloys, but they emphasized uncertainty about their data. Mima and Hasegawa4 studied the liquidus surface of Cu-Si-Zn alloys, phase transformations in high silicon-bearing (20 to 25 at. pet) alloys,5 and the phase relations in low silicon-bearing Cu-Si-Zn alloys.6 Their experiments were based upon thermal analyses and metallographic observations. The compositions of the phase boundaries were not determined with high precision, and the crystal structures of the phases were not reported. Because of uncertainties in the existing literature, it became of interest to determine more accurately the phase relations in copper-rich Cu-Si-Zn alloys. The crystal structures, stability, and phase boundaries of the primary solid solutions and several intermediate phases were determined, and the data are reported as partial isothermal sections.

Jan 1, 1964

By William Kent

I DESIRE to place on record in our Transactions a recent innovation in blast-furnace practice, namely, the introduction at the Lucy Furnaces, in Pittsburgh, of four water-tube steam-boilers, of the Babcock and Wilcox pattern, aggregating 832 horse-power, builder&apos;s rating, or 9,568 square feet of heating-surface, utilizing the waste gases of the furnaces as fuel. The boilers are set in two batteries, each of 416 horse-power, and each battery occupying a ground-space of 22 feet 7 inches by 20 feet 4 inches. The accompanying dram-

Jan 1, 1885

By T. B. Armstrong

Electrical energy conservation sees that service facilities are operated only when needed and that production equipment is operated under an optimum condition. Specific energy consumption (kw-hr per tonne) is not regularly recorded for comminution circuits because of variations in ore characteristics and the low grinding efficiency (0.1 to 2.0%) of the equipment. Improved data acquisition can produce meaningful results. Particle size monitor systems and density gauges permit comparison of energy (kw-hr) and production (tonne) for a "fixed" condition. Finding the operating condition producing the lowest unit energy consumption provides a target for an effective energy management program.

Jan 1, 1982

Mellon Institute of Industrial Research, University of Pittsburgh, Pittsburgh, Pa. The Mellon Institute of Industrial Research has carried on for years research and investigations for all type and manner of indus¬try. One of the provisions of the foundation of the Institute is the

Jan 1, 1933