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By W. N. Lacey, B. H. Sage, W. M. Morris

The volumetric behavior of isobutane at temperatures below its critical temperature has been studied by several investigators. Seibert and Burrelll measured the vapor pressure of isobutane from the ice point to the critical temperature. Dana and co-workers2 determined among other thermodynamic quantities the density of the saturated liquid and the saturated gas and the vapor pressure from approximately 0 to 130 F. Sage and Lacey3 studied a number of the thermodynamic properties of this hydrocarbon from 70" to 250" F. The specific volume in the gas and liquid region was determined at pressures up to 3000 Ib. per sq. in.? throughout this temperature interval. In addition, the vapor pressures were measured at 30" intervals. These data taken together serve to establish the thermodynamic behavior of isobutane at temperatures between 0" and 250" F. with reasonable accuracy. However, apparently there are no data available at the higher temperatures. For this reason an investigation of the volumetric behavior of isobutane at temperatures between 100" and 460" F. was carried out with apparatus that has been described in another paper (p. 136, this volume). Materials The isobutane used in this investigation was obtained from the Philgas Division of the Phillips Petroleum Co. That company's special analysis upon this sample indicated it to contain less than 0.03 mol per cent of impurities. In order to avoid traces of noncondensable gases, this hydrocarbon material was subjected to two successive fractionations at a high reflux ratio in a column approximately 4 ft. long and % in. in diameter, which was packed with small glass rings. The middle portion of distillate from the first fractionation was used in the second fraction-ation and a portion of the overhead from this second distillation process was repeatedly condensed at liquid-air temperatures at a pressure only slightly above the sublimation pressure of isobutane at this temperature.

Jan 1, 1940

Discussion of Papers. Meetings of the Institute offer opportunity for social acquaintance and exchange of ideas, for the presentation of papers, and for discussions thereon ; also incidentally for viewing under especially favorable conditions mining operations and industrial establishments, and for hospitals-ties which demonstrate the brotherhood due to kindred interests. Placing sociability prominent is not to be assumed as relegating other features of meetings to subordinate positions; but during about 40 years of membership in the Institute, the value of acquaintances formed (often ripening into close friendship), and the interchange of data, have frequently demonstrated that the social feature of meetings is of great and lasting value to the membership. Of' a roll embracing 4,011 members, resident in all parts of our country, and scattered in various portions of the world, only a small fraction are able to attend meetings, even if the localities selected are alternately widely separated. Hence, the return which most -members receive for their annual assessment of dues is limited to the publications issued, and the credit of being recognized as a member of a great and worthy organization. Tile greater the value of tile contents of our publication, the fuller the return which goes to members. While the Institute disavows responsibility for views or statements made in papers which appear in its Transactions, the fact that these contributions, after passing proper censorship, are accepted by the Institute and spread before the world may properly be received by the writers as endorsements of their (the writers') ability to present a specific technical or industrial proposition worthy of being carefully read. But the mere presentation and publication of contributed papers falls short of fulfilling one important feature of our meetings. If the purpose is confined to having the writers' views, discoveries, theories, or methods published, this can be obtained through the technical or trade journals and magazines.

Jan 7, 1913

By Franklin H. Allison

The influence of cobalt and nickel on the properties of steel might be readily expected to be very similar. The two elements occupy close and somewhat unusual positions in the periodic table, their chemical behavior and compounds are so completely analogous and their various physical properties, including the ferro-magnetic characteristic, show such 3 remarkable correspondence, that there is no doubt of a strong resemblance existing between these two metals. However, the variety of properties that are obtained from steel is due largely to the fact that the element iron possesses allotropic forms. Alloying elements that affect these allot ropic forms, or alter the nature of the allotropic changes, exert a profound influence on the resulting steel. In the case of nickel and cobalt, although these elements are very similar chemically and physically, it is found that they differ distinctly in their individual effects on the critical points of iron. Both nickel and cobalt form a series of homogeneous solid solutions with iron at temperatures above 1500" F. The difference in their behavior does not occur until changes begin to take place in the solid state below this temperature. An inspection of the respective thermal equilibrium diagrams at the lower temperatures makes the opposite effects of nickel and cobalt clearly evident. Effect of Nickel and Cobalt in Binary Alloys with Iron The binary diagram of iron-nickel has been investigated by a number of workers. The lower temperature portion in Fig. 1 is reconstructed from the data of D. and H, Hanson.1 The diagram of iron-cobalt, shown in Fig. 2, is taken from the work of Ruer and Kaneko.2 Masumoto3 has recently discovered a lower critical point in cobalt and this has been added to the diagram. In both diagrams the space lattice structures as determined by Andrews4 have been included. It is interesting to note

Jan 1, 1927

By A. S. Odeh

This paper analyzes the effect of limited entry to flow at the wellbore on the steady-state productivity of a well. Wells that have been opened to flow along a fraction of their productive interval are termed wells with limited entry. Previous work treated the cases of a partially penetrating well, a well producing from the central portion of the productive interval and a well in which several intervals equally spaced were open to flow. In this paper the open interval can be located anywhere within the productive interval. Thus, in a sense, it generalizes previous work. The finite cosine transform was used to arrive at a solution for steady-state flow of a slightly compressible fluid. The solution was programmed for a CDC 1604 computer. Numerical vaIues for rd = 660 ft, r, = 1/4 ft, and range of sand thickness of 20 to 200 ft are presented in graphical form. The effect of rd and r, values on the result is shown in a table. The correct calculation of skin and damage ratio in the presence of limited entry to flow is explained and illustrated by examples. Moreover, the paper shows how to calculate the net decrease in productivity due to the combined effect of limited entry and perforations. INTRODUCTION In some wells only a fraction of the productive interval is open to flow. Location of this fraction is usually dictated by formation characteristics and reservoir behavior. For instance, if a gas cap exists, the open interval is located away from the gas-oil contact to prevent any possible gas coning. Wells that intentionally have been opened to flow along a fraction of their productive formation are tened wells with limited entry. Obviously, unintentional completions of this type also exist. Limited entry to flow decreases well productivity. Magnitude of the loss depends on the fraction of the formation open to flow, on the thickness of the sand, on the location of the open interval and on the ratio of rd /r, where r , is well radius and rd is the drainage radius of the well. The use of pressure buildup data on producing wells to calculate the condition of the formation around the wellbore is an accepted practice. van Everdingenl and Hurst2 introduced the concept of she skin factor s considered to be due to a thin layer of different permeability immediately around the wellbore. These authors dealt with the case of a well of complete radial geometry, i.e., a well with open-hole completion that completely penetrates the formation. The presence of a low-permeability skin results in a loss of productivity, as does limited entry. Therefore, if pressure buildup data obtained on a well with limited entry are used to establish the presence or absence of skin (i.e., formation damage), and a correction is not made for this loss of productivity, the calculations would result in an erroneous skin value. They might indicate the presence of formation damage when in reality there is none, or they might indicate a value larger than the true value. This could lead to an incorrect basis for planning remedial measures. Muskat3 studied the problem of partially penetrating wells for the case of incompressible flow. He presented equations and figures which allow estimation of loss in productivity. Brons and Marting,4 using equations based on Nisle's work,5 studied the loss of productivity for three cases. The first was for a partially penetrating well; the second was for a well producing from only the central portion of a productive interval; and the third was for a well in which several intervals equally spaced were open to flow. Their work was for steady-state depletion-type reservoirs wherein the well radius of drainage is established and the fluid is considered to be slightly compressible. Considered in this paper is the problem of wells with limited entry in which the open intervals are located anywhere within the productive sand. The finite cosine transform is used to arrive at a

Jan 1, 1969

By A. H. Redfield

BITUMENS have been defined by Abraham1 as substances of variable color, hardness, and volatility; composed principally of 'saturated hydrocarbons, substantially free from oxygenated bodies, sometimes associated with mineral matter; the nonmineral constituents being fusible and largely soluble in carbon disulphide. The principal bituminous substances other than petroleums known to commerce are: (1) native asphaltites, such as gilsonite, grahamite, and glance pitch, distinguished by their hardness and relatively high fusing point; (2) native asphaltic pyrobitumens, such as wurtzilite, distinguished by their infusibility and comparative insolubility in carbon disulphide; (3) mineral waxes, such as ozokerite, distinguished by their high content of crystallizable paraffins; (4) native asphalts, containing varying amouqts of mineral matter, distinguished by the comparative absence of crystallizable paraffins; and (5) bituminous residues obtained from the distillation of petroleum. GILSONITE Gilsonite, a black native asphaltite 98 to 99.9 pct pure, characterized by a hardness of 2 (Mohs), a specific gravity of 1.01 to 1.10, and melting point of 230° to 400°F (K and S), is mined commercially only in northeastern Utah. It occurs in parallel, almost vertical veins, from a few inches to 18 ft wide and 8 to 30 miles long, that cut across the Tertiary limestone and shale of the broad Uinta Basin. The bitumen is believed to have been distilled by heat from oily material in the underlying Green River shale. At the Rainbow mine of the American Gilsonite CO.,† the gilsonite, formerly extracted in an opencut by a system of slopes and benches, is now mined by shafts and horizontal drifts. Little timbering is required. The mining methods of the Raven Mining Co., Chicago, and of the American Asphalt Association and the Utah Gilsonite Co., both of

Jan 1, 1949

By Alexander N. Mitinsky

UP to a certain limit, the increase of pressure on the diamond-drill increases the rate of progress in drilling. That limit is set by the resistance of the diamonds to compression; and beyond it, the destruction of the stones will involve an. economic loss, both in time and in money. It is, therefore, important to all diamond-drillers to know what is the resistance mentioned. In Europe, operators usually follow an empirical rule, which directs the maintenance of a pressure, on the area-of the bottom of the drilling-tool, of 12 kg. per sq. 4m. For the tools in ordinary use, this is equivalent to 1 kg. per sq. mm. of the diamonds set in the tool So far as I know, American drillers are using pressures as high as 50 to 60 kg. per sq. cm. of the total area of the drill, and the consumption of diamonds (on Denny's authority, 0.2 carats per meter bored) is greater in America than in Europe. But the reason for this difference may be the comparatively larger size of the diamonds commonly used by American drillers. With the assistance of my friend, the late S. Woisslaw, who was the pioneer of diamond-drilling in Russia, I selected from his stock a number of black diamonds, which I subjected in my laboratory to compression-tests. To prepare regular cubes for such tests, as is generally done with other stones, would have been not only costly, but, what is more important, practically useless. I therefore determined, in order to assimilate as nearly as possible the conditions of actual use, to place each sample between a hard plate (corresponding to the rock) and a softer plate (corresponding to the bottom of the tool), into which it would be pressed during the test.

Jan 1, 1906

By R. E. Reed-Hill

A simple accurate graphical method for orienting fcc crystals using (111) slip traces on a single surface is described. Solutions placing the pole of the surface in a unit stereographic triangle are obtained using a Wulffnet, a (111) standard projection showing the four (111) planes, and a (111) standard projection ruled into unit stereogmphic triangles. The multiplicity of solutions is described in relation to this method. AN accurate, rapid single-surface technique for orienting fcc crystals, using (111) slip or twin traces, has been a matter of continuing interest, as evidenced by the periodic appearance of papers on this subject.'-4 This note presents a new method possessing some advantages over those previously reported. It is an analog to the technique for hcp metals5 where the solution is based upon a stereographic rotation of the specimen surface on a (0002) standard projection that contains the planes of the possible features that might account for the observed traces. In the hexagonal solution, the axis of rotation is the basal-plane trace in the surface. In the fcc case, the axis of rotation is one of the observed ( 111) slip or twin traces. It has been observed that the solution is greatly facilitated if the indicated movements of the (111) traces during the rotation of the surface are plotted directly on a paper copy of a Wulff net as shown schematically in Fig. 1. The trace selected to represent the axis of rotation is assumed to fall at the north-south poles of the Wulff net. The directions of the other traces are then plotted as points at the proper angles around one-half of the basic circle of the net. The loci of points corresponding to the movements of these traces (directions) during a 90-deg rotation of the surface, about the polar axis of the net, are then easily and accurately drawn by following the appropriate small circles on the Wulff net. The solutions to the problem are obtained with the aid of a (111) standard projection of the (111) planes, see Fig. 2. This is normally a Xerox copy of a carefully drawn master made on high-quality tracing paper. The (111) standard projection is superimposed over the Wulff net and rotated about its center until the points of intersection of the loci of surface traces, drawn on the Wulff net, and the great circles representing the (111) traces, all lie along a common meridian of the Wulff net as demonstrated in Fig. 3. This latter great circle represents a possible position of the surface. The pole of this plane is then plotted on the (111) standard projection. Its location in a unit stereographic triangle may be readily obtained by superimposing (over the standard projection) another tracing paper (111) standard projection subdivided into unit stereographic triangles. The result of this last operation is shown in Fig. 4. MULTIPLICITY OF THE SOLUTIONS The maximum possible number of (111) traces on a single grain surface is four. Any one may be selected as the axis about which the surface is rotated. Corresponding to each such choice are three possible surface-pole orientations, related to each other by a simple 120-deg rotation about the pole of the (111) basic circle. This is a direct result of the threefold symmetry of the (111) standard projection. Since each of the four rotations will normally give a different set of three-pole positions, there are, accordingly, twelve possible solutions. Each of these twelve solutions places the surface pole in the same relative position in a stereographic triangle so that all are crystallo-graphically equivalent. Accordingly, only a single solution is required to obtain a basic orientation of the crystal. It should be noted, however, that the orientations obtained by reflecting* any of these twelve orien- *The reflected orientations may be obtained by a 90-deg rotation of the opposite sense to that shown in Fig. 1. This rotation places the correspond-ing trace loci in the lower hemisphere of the Wulff net rather than in the upper hemisphere. tations through the surface are also possible orientations that could account for the surface traces. Thus, a given set of four traces always corresponds to a pair of basic orientations related by reflection through the specimen surface. This ambiguity can only be re-

Jan 1, 1967

By B. M. Loring, I. R. Kramer, F. M. Walters

No observations on the mechanical properties of iron-manganese alloys have been published since pure manganese became readily available, either distilled manganese or electrolytic manganese. The purpose of this investigation was to determine whether iron-manganese alloys are essentially brittle, as reported by Hadfield,1 or whether the lack of ductility observed was due to impurities in the alloys that he studied. EXPERIMENTAL METHODS The alloys were melted in a 100-lb. high-frequency induction furnace with a magnesia crucible, using ingot iron and electrolytic manganese. The heats were split, the first giving six 18-lb. ingots and the second three. Each successive heat was higher in manganese and about 0.3 per cent silicon [ ] was added as ferrosilicon. The alloys forged without difficulty-and were given a 90 percent reduction to 3/4-in. rounds. The chemical analysis of the alloys is given in Table I. The forged rods were homogenized for [ ] 24 hr. at 1150°C. (2100°F.) and air-cooled. The alloys were tested in two conditions of heat-treatment: (I) as normalized from 870°C. (1600°F.) and (2) normalized from 870°C. and tempered for z hr. at 540°C. (1000°F.) and air-cooled. The tensile specimens were 0.505 in. in diameter with a 2-in. gauge length, and the impact specimens were V-notch Charpy. The proportional limit and yield strength were taken from the stress-strain diagrams drawn by a Peters recorder. The data obtained from the tensile test and the hardness measurements are given in Table 2. Specimens that were normalized are designated by N; those that were normalized and tempered by T. Alloy G was tempered after forging (D).

Jan 1, 1941

By Edwin R. Phelps, Charles W. Porterfield

BACKGROUND OF SURFACE MINING Surface mining refers to the process of removing the material (over- burden) overlying a coal seam and exposing the coal so that it can be loaded out and conveyed by trucks or other methods to the preparation plant or other facility. Surface mining has not always been important in the coal industry. In the early 1900s, almost all of the coal mined in the United States was mined by underground methods. In 1900, about 192 Mt (212 million st) of bituminous coal were mined and less than 1% was mined by surface methods. The development and use of larger equipment has allowed surface mining to gain prominence throughout the years. Table 1 shows the total production of coal by mining method in the United States for ten-year periods since 1920 and indicates the growth of surface-mined coal production. Surface mining will undoubtedly continue to account for a large percentage of the coal production in the US for many years because: 1) The capacity of surface mining excavators has continued to in- crease. Today, mining companies are using shovels (see Fig. 1) which are able to move up to 137.6 m3 (180 cu yd) in each bite and draglines (see Fig. 2) which move up to 168.2 m3 (220 cu yd) in each bucketful. 2) Increasing tonnage from the thick western coal seams is being produced by surface mining methods. 3) Surface mining has normally had lower costs and a better safety record than underground mining. 4) Surface mining normally recovers a much higher percentage of the coal reserve than can be recovered by underground mining. 5) Some coal measures can best be extracted by surface mining

Jan 1, 1981

By J. T. Eash, E. M. Wise

In a previous communication1 the improvement in slrength, harden-ability and color, occasioned by replacing gold in a typical gold-silver-copper alloy by various amounts of platinum, or palladium, was discussed. In the present paper the results of further studies upon the constitution and the nature of the hardening transformation in these alloys are presented. This research may be summarized as follows: 1. The liquidus and solidus have been determined for the alloys of the palladium and platinum series. Cooling curves were utilized for determining the liquidus of the palladium alloys but this method proved unsuitable for the platinum alloys so that a novel quenching method was utilized for the latter. Both the liquidus and solidus of the palladium alloys increase steadily with the palladium content. The liquidus of the platinum alloys increases rapidly with the platinum content, while the solidus temperature increases with the platinum content up to about 14 atomic per cent platinum, but suffers no further increase with additional increments of platinum up to 20 atomic per cent at least, owing to a peritectic reaction. 2. Palladium, and even more effectively platinum, reduces the rate of grain growth. Owing to this fact and to the increase in the solidus temperature, "overheating" does little or no damage to alloys containing reasonable quantities of these elements. This is confirmed both by tensile tests and metallographic examination. 3. The excess phase present in one of the high-platinum-content alloys has been isolated and chemically analyzed and was found to consist almost wholly of platinum, gold, and copper, evidently derived from the compound AuCu, by the partial replacement of gold by platinum. 4. The variation in the solubility of this platinum-content phase in the alpha solid solution with the temperature has been determined. This

Jan 1, 1933

By Charles G. Maier

It has long been supposed that when crystalline materials are comminuted the energy used in the production of increasingly smaller grain sizes is not entirely dissipated as heat but that a certain portion is "stored" as a part of the internal energy of the material. This portion usually has been called the "surface energy" of the particles. The practical interest of the Bureau of Mines in this subject in connection with the energy requirements of crushing processes has led to the author's attempt to measure the "stored" energy in finely divided calcite by heat-of-solution methods1.t The experiments on calcite showed that "storage" of energy could not be proved for this material, because fine grinding caused a lack of chemical homogeneity evidenced by loss of carbon dioxide and subsequent adsorption of water on the surfaces of the calcite particles. When thermochemical correction was made for composition changes the corrected heat of solution was less for fine material than for coarse. Continuation of the experimental work into the problem of comparing work and heat in the deformation of metallic crystals, where the calorimetric difficulties were less, showed, however, that in the case of copper and aluminum a real discrepancy between work and heat could be shown. Similar results had previously been obtained by Farren and Taylor2 and Hort3 and more or less simultaneously with the author's work by Rosenhain and Stott4 and by Taylor and Quinney9 The results obtained by the different investigators were not satisfactorily consistent, but the experiments of Taylor and Quinney constitute by far the best figures obtained to date. The previous paper1 presented evidence to show that if energy is stored in the surfaces of crystals the densities of fine crystals should differ

Jan 1, 1936

By Thomas H. Leggett

IN speaking of the mining and economic conditions prevailing at the present time on the Rand, it is not my intention to go into the details of the mining-practice, since this has been already well described both in the Transactions1 and elsewhere,2 but rather to take a more comprehensive view of the industry and its surroundings as a. whole, marking its general development and the lines of its future progress. In a. paper entitled Deep-Level Shafts on the Witwatersrand, with Remarks on a Method of Working the Greatest Number of Deep-Level Mines with the Fewest Possible Shafts,3 presented to this Institute in August, 1900, I drew attention to the great cost of sinking the very deep vertical shafts that were then being seriously proposed as necessary for the development of the deeper areas, pointing out the strong advisability of working this ground by means of inclines to be sunk from the existing shafts of from 3,000 to 4,000 ft. in vertical depth. In this paper it is stated (1:). 975): "In short, practice upon the Rand now tends towards fewer vertical shafts and more underground inclines, especially for the very deep mining about to be undertaken." In consequence, the 6,000-ft. vertical shafts, at one time so much discussed, have never been started, and they do not now seem likely ever to be. The necessity of placing all deep shafts further apart in order to make them control and exhaust larger areas was also dwelt upon. This economy was vitally necessary for both 1 Gold-Mining in the Transvaal, South Africa, John Hays Hammond, xxxi., S17 to 855 (1901). R Engineering and Mining Journal, vol. lxxxv., p. 53 (1908). ' Trans., xxx., 947 to 987 (1900).

Jan 5, 1908

By H. B. Smith, B. Egererg

In a previous paper1 the authors dealt with the physical properties of cold-rolled and heat-treated Britannia metal of the approximate composition Sn, 91 per cent., Sb, 7 per cent. and Cu, 2 per cent. It was found that cold rolling to more than 50 per cent. reduction produced a continuous softening of the metal when measured by the Brinell machine, whereas the Shore instrument indicated increased hardness; that the strength of the material followed the Brinell hardness and that the metal therefore became weaker the more it was cold-rolled; and further, it was found that hardness and strength could be largely restored to the cold-rolled metal by "baking" for about one hour at any temperature between 200" and 450" F., the melting point. The higher the baking temperature, the more effective was the heat treatment as far as increased hardness was concerned. It seemed to be of little importance whether the metal was soaked or not at the baking temperature for a great length of time and the rate of cooling seemed to be immaterial. The present paper deals with the same alloy and more particularly with the resistance towards various forms of stress — tensile, bend and deep drawing. The metallography of Britannia metal has in part also been covered and an explanation attempted for the abnormal behavior of this alloy. Tensile and Bend Tests Two ingots 73/4 in. wide, 11 in. long and ¾ in. thick were cast from the same pot. One ingot was cold-rolled in one direction to a strip 0.241 in. thick, which furnished the tensile test specimens; the other ingot was rolled in the same way to 0.253 in. and furnished the specimens for the bend tests. The ingots were cast as described in the previous paper and cold-rolled in six passes.

Jan 1, 1930

By J. W. Ristori

During the year 1940, production of crude oil in RiIexico totaled 43,914,000 bbl., or 2,776,000 less than in 1937, the year before expropriation. The 1940 output was I,2000,000 higher than in the previous year. In 1937, Poza Rica production accounted Declines in exports of Panuco crude, fuel oil and gasoline were recorded but these were more than offset by increased exports of 4,000,000 bbl. of Poza Rica crude, which was the approximate amount shipped to Sinclair during 1940 under the terms of the settlement. Over-all exports increased by 1,500,000 bbl. over the preceding year. The outstanding development regarding the destination of Mexican exports in 1940 was the increase of I0,000,000 bbl. in the exports to the United States. Exports to Germany ceased toward the end of '939 and to Italy in the second half of 1940. During the year 1940 the Sinclair interests and the Mexican Government settled their expropriation question. By the terms of the settlement Sinclair is to be compensated by cash payments and oil-purchase contracts. On Dec. I, 1940, Ada Camacho was inaugurated President of Mexico for a term of six years. Among his first acts following his election were: I. A proposal to change the Constitution to restore Supreme Court Judges' terms to life tenure. This has been ratified by both chambers of the Mexican congress and is now before the legislatures of the States of Mexico for ratification. The, taking away of the administration of the railroads from labor and restoration to the State.

Jan 1, 1941

By J. W. Ristori

During the year 1940, production of crude oil in RiIexico totaled 43,914,000 bbl., or 2,776,000 less than in 1937, the year before expropriation. The 1940 output was I,2000,000 higher than in the previous year. In 1937, Poza Rica production accounted Declines in exports of Panuco crude, fuel oil and gasoline were recorded but these were more than offset by increased exports of 4,000,000 bbl. of Poza Rica crude, which was the approximate amount shipped to Sinclair during 1940 under the terms of the settlement. Over-all exports increased by 1,500,000 bbl. over the preceding year. The outstanding development regarding the destination of Mexican exports in 1940 was the increase of I0,000,000 bbl. in the exports to the United States. Exports to Germany ceased toward the end of '939 and to Italy in the second half of 1940. During the year 1940 the Sinclair interests and the Mexican Government settled their expropriation question. By the terms of the settlement Sinclair is to be compensated by cash payments and oil-purchase contracts. On Dec. I, 1940, Ada Camacho was inaugurated President of Mexico for a term of six years. Among his first acts following his election were: I. A proposal to change the Constitution to restore Supreme Court Judges' terms to life tenure. This has been ratified by both chambers of the Mexican congress and is now before the legislatures of the States of Mexico for ratification. The, taking away of the administration of the railroads from labor and restoration to the State.

Jan 1, 1941

By W. W. Lowry, G. C. Eggleston, W. E. Keck

THE potential iron ores of Michigan can be classified from the stand- point of the predominant impurities into siliceous, sulphurous and phosphorous ores. Research on the flotation of each of these classes of ore was carried out in the following manner. The flotative properties of the valuable minerals of iron and of the worthless and deleterious ones were first determined under carefully controlled conditions. This information was then applied to synthetic mixtures of these minerals, which simulated the potential ores. Finally, data obtained during the two foregoing stages of the investigation were used in the flotation beneficiation of samples of the potential ores. Hematite is the most important mineral of iron in each of the above classes of iron ores. This paper deals with a study of that mineral in the very nearly pure state. There are two varieties of the mineral-specular hematite and massive hematite. The latter is the principal variety, but the former is an important mineral of iron in some of the potential ores. Because of this condition, flotation research was performed with both varieties. This research consisted essentially of: (1) a survey of the literature on hematite flotation, (2) the preparation of pure massive hematite, (3) the preparation of pure specular hematite, (4) the development of a laboratory procedure and (5) flotation experimentation. For the purpose of this discussion, the results of previous work on the flotative properties of hematite can be summarized as follows: Specular hematite has been readily floated with terpineol and sodium oleate or heptylic acid1. Further, hematite has been likewise floated with a proprietary frother and oleic acid or other soluble oils2. Finally, lead nitrate, copper sulphate, silver nitrate, chromium nitrate, mercuric chloride, ferric

Jan 1, 1937

By W. R. Shimer, F. O. Kichline

The investigation herein described was carried out for the purpose of studying, both by chemical and metallographical means, the extent of over-oxidation of steel that can be accomplished by excessive overblowing in a Bessemer converter. 111 addition there are appended some results of basic open-hearth and crucible steels. Remarks on Chemical Methods. The test block used was hemispherical in shape, 4.5 in. in diameter and 2 in. thick. Drillings for analysis were obtained by drilling through the entire solid part of the block, carefully avoiding all cracks and blow-holes and mixing these drillings thoroughly. Drillinga were carefully examined for scale and the finest were gone over with a microscope to be sure all scale from whatever source had been removed. Oxygen was determined by the well-known method of Ledebur, modified according to Cushman,1 with, however, the removal of the preheating tube, which was found unnecessary. This method has been found to give concordant results. Blanks run from 0.0003 to 0.0006 g. Duplicate determinations varied not more than 0.001 to 0.003 per cent. It seems to be generally supposed that the hydrogen method gives only that oxygen which is combined with iron. Whether this be true or not, the content of oxygen existing as iron oxide no doubt predominates sufficiently, so that the result obtained is sufficient to indicate whether the steel is over-oxidized or not. We are well aware that the oxides of manganese and chromium, when existing alone, are not reduced by hydrogen at a red heat. To learn of their action in steel the following work was carried out: A sample of ferro-manganese and of ferro-chrome were each exposed

Jan 1, 1914

By K. E. Beu

IN the measurement of retained austenite concentrations in steels using the integrated intensity method,1 Averbach has pointed out" that the absorption factor A(0) for a flat sample making a glancing angle 4 with the incident X-ray beam can be combined with his constant factor R to obtain our constant factor" G provided that "1—There is no preferred orientation in the sample, and 2—The geometric requirements [for the sample, film, and X-ray beam] have been met precisely."' If A(0) can be combined with R to give G according to the equation G = R . A(0) [14] then the possibility for making non-compensating errors in the austenite determination has been eliminated. This has been described previously in a technical note." Because of the brevity of the previous note,3 it was impossible to emphasize the fact that the two conditions on preferred orientation and geometry can be easily met experimentally, contrary to Aver-bach's statement that: ". . . the necessary conditions must be tested experimentally for each determination, and this is done most easily by observing whether the apparent absorption has the form of Eq. 2 [the theoretical equation for A(0)]."" he way in which these two conditions can be met experimentally will be discussed briefly to help clear up this point. In addition to these two conditions, other factors such as sample shape, homogeneity, and grain size which also affect A will be included in this discussion. A (0) depends on sample shape. The theoretical function for A was derived originally for a flat surface.' In general we have found that a flat sample surface is readily obtainable." If such a surface can * The effect of surfaces which are not flat on the measurement of retained austenite will be discussed later. be obtained, it has the following advantages: 1—it is easily reproducible from sample to sample, 2—it is the form required for metallurgical examination —this type of examination being frequently desirable for this work, and 3—it is an efficient shape for diffraction purposes. Perhaps the most important of these features is that a flat sample surface is easily reproducible; hence, this requirement on the repro-ducibility of A from sample to sample is met for all such samples. Fig. 1—Schematic diagram of the quartz crystal monochromator diffraction unit. The centerline of the main beam is at 6' to the target face. The tangent to the crystal face is at 16.8' to the moin beam. The centerline of the monochromatic beam is at 33.6 to the main beam. The sample surface can be rotated in its own plane. The angle of the sample surface and the monochromatic beam can be adjusted by rotating about the vertical axis, The film holder can also be rotated about B so that the film can be exposed over the desired angular range. For Fe K, X = 1.932A. 1011 planes of quartz have d = 3.35A. A(0) depends on homogeneity and grain size. If the sample is badly segregated or the grain size is large, the effect of micro-absorption and primary extinction1. ' must be considered. It has been shown, however, that for most plain carbon or low alloy hardened steels, neither micro-absorption nor primary extinction effects are present.' A (0) depends on camera geometry. For a given angle 0, A remains theoretically constant from a geometrical viewpoint only if the following factors are kept constant: 1—the angle of inclination .+ of the sample to the X-ray beam, and 2—the centering of the sample with respect to the film cylinder. These are mechanical problems which can be solved readily if the facilities of a good machine shop are available. The arrangement used to insure that the angle 4 remains constant and the centering of the sample is reproducible is indicated schematically in Fig. 1. The sample is clamped against a thin plate with a hole in it by means of a spring-loaded pres-

Jan 1, 1954

By Henry W. Edwards

Concrete is not a new, nor even a modern substance. Important structures built by the old Romans before the commencement of the Christian Era are to-day sound and solid— for example, the dome of the Pantheon in Rome, 142 ft. in diameter. I do not propose, therefore, to discuss the durability of the material, as in the mining and metallurgical business, structures, as a rule, are not calculated to endure for two thousand years. I do wish to urge, however, that much of the stone masonry around mines and smelters would have given better results if concrete had been used in place of stone. Concrete looks better; is stronger, cheaper, more durable, more quickly built, and above all requires no skilled labor, except that of the carpenter, who, like the poor, is always with us. Well proportioned concrete, that is to say, having well proportioned ingredients, may be safely relied upon to withstand a compressive or crushing strength of 50 tons per square foot. In most American cities, however, the building laws limit it to the absurdly low figure of 16 tons. This restriction is probably due to the political influence of the building-trades unions, which object strongly to its too free use, undoubtedly owing to its not requiring the services of skilled workmen. I hope to show that quite important construction work may be' undertaken without the aid of the gentleman with the trowel. In some of the isolated districts of the West and Southwest this is no mean advantage. The weight of good concrete, dry, is from 130 to 160 lb. per cubic foot. Ingredients of Concrete. Concrete is composed of four ingredients; viz., 1. Crushed Stone; 2. Sand; 3. Cement; and 4. Water.

Jan 1, 1905

By K. Tangri, B. Swaroop

Simultaneous measurements of lattice (elastic) strain by X-ray line shift method and total strain with an electrical strain gage have been carried out on polycrystalli,ne nickel with the help of a specially designed tensometer attachment for the X-ray dif-fractometer. During the initial stages of deformation, the rate of increase in lattice strain closely follows the total strain until the plastic strain sets in. From then onwards, the two strains deviate from each other and with further increase in afiplied stress the rate of increase of lattice strain eventually decreases. Depending upon the mode of unloading, both compressive and tensile strains have been observed in nickel deformed up to 0.29 pct strain. These results have been explained on the basis of the effects of clustering of dislocations and also the production and behavior of point defects during loading and unloading, respectively. POLYCRYSTALS deformed plastically in a uniaxial tension test show residual lattice strains (hereafter referred to as RLS), which broaden the X-ray line profiles and shift their peak positions.''4 It is known that uniform straining of a crystal lattice (macrostrain) produced movement of ddfraction line peaks, whereas nonuniform straining (microstrain) causes line broadening.= Though the nature and origin of RLS in deformed metals is not yet clearly understood, these are believed to be due to the presence of some form of a locked-up stress system. Several possible detailed interpretations6'" of the stress system have been proposed by various workers and common to all these interpretations is the assumption that different parts of the aggregate have different tensile yield stresses; e.g., that a part A yields under a lower applied stress than a part B. Therefore, during the deformation process, the elastic strain in A will be less than that in B, and, after completion of deformation, B will tend to contract further than A but will be prevented from doing so by the restraining influence of A. Thus, when equilibrium is reached, A will be in compression while B is in tension. Although there is general agreement on the correctness of this argument, controversy still exists as to the exact nature of the parts A and B in a deformed metal. In an alternative approach to the creation of parts A and B, many other investigators have assumed that the RLS observed in unloaded specimens are in some way connected with the lack of proportionality between lattice strain and applied stress in the region above the yield stress." cullity13 has prepared a schematic summary of the results of previous workers, mainly Smith and Wood,2'11 which suggests that, above the elastic limit, the lattice strain may increase less rapidly with respect to strain, or may even decrease with increase in applied stress. If the applied stress is then decreased, the lattice strain would decrease along a line parallel to the loading line in the elastic region and thus produce a compressive residual lattice strain after unloading. At equilibrium, to balance these compressive stresses? there would have to be regions under tensile stress which may well be the grain boundaries or the substructure walls formed during deformation. The present investigation was undertaken to gain a better understanding of the nature and origin of RLS and also to experimentally verify the salient features of this hypothesis. EXPERIMENTAL Stress and strain determinations were made with a specially constructed tensometer attachment for the X-ray diffractometer, Fig. 1: which permits the following measurements simultaneously on a sheet specimen under uniaxial tension at various stress levels during loading and unloading: a) lattice strains, E=. in a direction perpendicular to the direction of pulling (x direction) from shifts in X-ray line peak positions; b) the total strain, ex, in the direction of pulling. with the help of an electrical strain gage affixed to the back of the specimen directly below the area irradiated by X-rays: and c) the applied stress, with the help of a load cell which consisted of a calibrated stainless-steel sample of dimensions identical to those of the specimen under investigation, and to which it was coupled. Because of its high stacking fault energy.I4 nickel

Jan 1, 1970