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By J. W. Fuller

During the last 20 years, experimenters have sought to utilize pulverized coal in boiler plants, but refractory and slag troubles have usually overbalanced any gains in efficiency that were obtained. These troubles were caused largely by lack of knowledge of the proper methods of coal preparation and lack of a furnace design that would be adaptable to pulverized-coal firing. When this information was obtained the results were so much more satisfactory that within the last 5 years approximately 80,000 boiler hp. have been installed in plants ranging from 1000 to 20,000 boiler hp. rated capacity, which are operating at an average of 174 per cent. of rating. The first commercial installation for burning pulverized coal under boilers was made at the Parsons shops of the M. K. & T. railroad in 1916. Of eight 250-hp. water-tube boilers thus fitted, six were operated continuously for 3 yr., when oil was obtained at such a low price as to warrant its use. Since then, this plant has been operating alternately on pulverized coal and oil, depending on prevailing prices. Recently gas has been discovered within 20 mi. of this plant, so that this fuel may also be used. No change in furnace design was made when changing from pulverized coal to oil or gas firing. One of the principal advantages of this method of firing is its ability to utilize, with maximum efficiency, all kinds of coal, irrespective of quality or physical characteristics. In fact, quite a number of the present pulverized-coal installations were made for the purpose of utilizing coal that could not be marketed or used in any other way. The Pacific Coast Coal Co., at Black Diamond, Wash., formerly hand fired the boilers, using approximately 125 tons of prepared steam-size coal daily. The Black Diamond steam coal is the best quality of coal for steaming purposes mined in that section of the country, and there is a market for all that can be produced. By installing a pulverizing plant, it was possible to substitute coal of a size and quality that had no commercial value, so that 125 tons daily of the best steam coal formerly used at the mines is now marketed. This company made a similar installation, at its New Castle, Wash., mine with approximately similar results. Each of these two plants has a

Jan 1, 1922

By M. Kitada, U. Kawabe, F. Ishida, T. Doi

The relations between micros tructures and critical current density in transverse magnetic field were experimentally investigated due to each transformation of the 0 to 0' + P" phases at 700' C for superconductmainly examined using replication electron microscopy. The ß' or a precipitates were found to pin down magnetic flux lines in these alloys. The effects of precipitation upon the critical current density were discussed in relation with the size, spacing, and characler of these precipitates. HIGH magnetic field superconductors, such as Nb-Zr, Nb-Ti, and Nb-Zr-Ti alloys, have been recently put to extensive practical use as winding materials for superconducting magnets.13 The critical current density of these hard superconductors under an applied magnetic field is an important characteristic for magnet materials and is very sensitive to metallurgical structure. It is generally known that the critical current density is increased by introducing dislocations and precipitates into a superconductor; that is, dislocations and precipitates are presumed to be barriers that hinder quantized flux lines from moving.4'5 Theoretical6'7 and experimental analyses of the motion of flux lines and the interaction between flux lines and various defects have already been reported by many authors. Metallographic analysis of high magnetic field superconductors such as Nb-Zr and Nb-Ti is difficult, so that no quantitative relationship between microstruc-ture and critical current density has been established yet. In this paper, the effect of precipitation on the critical current density in magnetic field was investigated for two superconducting alloys, Nb-40Zr-10Ti and Nb-5Zr-60Ti. In these alloys the resistive critical field H, at 4.2oK was about 100 kG and the critical current density Jc at 80 kG was of the order of 104 amp per sq cm.13-l5 The superconducting properties were examined in relation to the microstructural changes due to transformation of i) the ß to ß' + ß" phases at 700°C for Nb-40Zr-10Ti alloy and ii) the ß to a + ß phases at 500°C for Nb-5Zr-6OTi alloy. The effect of size, spacing, and character of precipitates on flux line pinning was in particular examined. The microstructures were studied by means of residual resistivity, microhardness, and tensile strength measurements as well as by X-ray diffraction, optical, and replication electron microscopies. I) EXPERIMENTAL PROCEDURE Pure niobium, zirconium, and titanium, in the form of rods 0.8 cm in diam, served as raw materials. Results of chemical analyses of these rods are given in Table I. Ingots of the alloys, 0.4 cm in diam and 3 cm in length, were prepared by means of levitation melting, utilizing a copper mold in an argon-gas atmosphere. Samples from the ingot then were cold-worked by grooved mill to 0.2 cm in diam, heat-treated homogeneously (in the ß phase region) for 5 hr at 1100° in a vacuum of 1 x 106 Torr, and finally cold-drawn to 0.025 cm in diam. For heat treatments, samples were wrapped in niobium foil and sealed in an argon-gas atmosphere in fused quartz capsules. Water quenching was done after each heat treatment. Subsequently H-J, were performed at 4.2° by slowly transporting the current through the samples 4 cm long, under transverse magnetic field, until the least detectable resistive terminal voltage was observed. The resistive critical field H, was taken as the field at which 100 pv appeared at 4.2°K across a sample 3 cm in length, with a current of 5 ma. The critical temperature T, was measured by means of a conventional four-probe resistivity technique and taken as the temperature at which the sample resistance reached one-half of full restoration of the normal-state resistance with a current l ma flowing through a sample 2 cm in length. Precipitates were observed by means of optical microscopy and carbon replication electron microscopy. The etching solution consisted of 5 ml HF, 10 ml H2SO4 10 ml H2O2, and 50 ml H2O, and shadowed carbon replicas were examined in a itachi HU-11 electron microscope operated at 50 kv. X-ray diffraction photographs were taken by a 11.46-cm-diam Debye-Scher-rer camera using copper Ka radiation. The micro-hardness was measured under a load of 200 g using

Jan 1, 1969

By L. J. Klinkenberg

It is pointed out that the current concept of pore size distribution is not unequivocally defined and that different methods aiming at a determination of such a distribution therefore do not lead to the same results. A pore size distribution should not be based on the idea that a core should, under all circumstances, behave as a bundle of straight non-interconnected capillaries of the same pore size distribution. This is illustrated by calculations and experiments on the displacement of miscible liquids. INTRODUCTION The introduction of the concept of pore size distribution has been an attempt to characterize the intricate geometry of the flow channels in porous media. As pores in a porous medium are interconnected it is impossible to describe exactly what is meant by a "pore" and, therefore, the term pore size distribution requires further amplification. In the visual method for the determination of pore size distribution "the pore" is considered to be the hole between the grains as observed on thin sections or on a polished surface of the rock under a microscope. In all other presently known methods,1,2 a displacement process is studied and it is ascertained what as- semblaae of straight cylindrical capillaries would show the same behavior. The distribution of the capillary diameters of this assemblage is said to represent the size distribution of the pores of the actual porous medium. From the foregoing it is already apparent that it is useless to try to decide which process or which method of investigation leads to a "correct" pore size distribution. To illustrate this further a displacement process in which a fluid is displaced by another miscible with it will be discussed and the results will be interpreted in terms of a pore size distribution. DISPLACEMENT EXPERIMENTS WITH MISCIBLE LIQUIDS OF NEARLY IDENTICAL VISCOSITY AND DENSITY Interpretation in the Form of a Pore Size Distribution If distilled water is displaced from a homogeneous unconsolidated sand pack by, for instance, a dilute solution of NaCI, the breakthrough recovery i.e., the amount of distilled water produced at the moment the first trace of NaCl can be detected in the effluent water, is between 95 and 100 per cent of the pore volume of the pack. This result can be understood by following in imagination the course of one particle of the liquid. Imagine a length, ?l, at the end of which a liquid particle has an independent chance of a renewed choice of pores of different diameters. In other words, the particle has a choice of traveling time, at, for any length ?l; instead

Jan 1, 1958

JOSEPH DANIELS, Seattle; Wash. (communication to the Secretary*). Mine models are of great value to the student and to the layman in visualizing underground conditions, and, in a measure, should be just as much a part of the equipment of a mining school as sets of ore specimens, catalogs, or drawings. The chief drawback, as Professor Stock has indicated, is the time and cost of making them. The greatest good in the development of the model comes to the person who makes it, and I have often wondered whether it might not be possible to have each student make one model during his undergraduate career. At the University of Washington we have been collecting sets of mine timbers, made of 6 by 6-in. lumber, illustrating shaft, level, and stope timbering. This work has been done by freshmen. Perhaps each educational institution could specialize in the creation of a certain type of model and exchange its product for that of another school, just as we now do with ore collections. In this way we could build up good museums at a relatively low cost. JOHN R. CHAMBERLIN, New York, N. Y. (communication to the Secretary?).-The type of model described by Professor Stoek is admirably suited to exhibits of coal mining in horizontal veins, and fulfills perfectly the three purposes mentioned. As an educational illustration in colleges, especially when the students themselves build the model under the direction of their instructors, it is of the highest value; and as each condition in mining requires special methods to depict properly in a model, the student is compelled to exercise considerable inventive resource to construct a true representation, stimulating the imagination and interest in his subject. Models built for exhibits in lawsuits are usually constructed to show prominently some particular feature of vein formation or geology, or the relation of underground workings to surface property lines, and as such their use is invaluable to the successful litigant. When the litigation is ended, it is natural that the model should be relegated to the basement and frequently destroyed, as data on underground workings are often considered of a private character by the operators; and it is

Jan 10, 1917

In the past few years the hydraulic aspects of rotary drilling have received considerable attention. It is generally recognized that accurate prediction of circulating pressures is desirable, particularly in those areas where a delicate pressure balance is necessary to prevent both blowouts and lost circulation. For calculation purposes the standard hydraulic equations for the pipeline flow of Newtonian fluids have been altered to facilitate similar calculations for non-Newtonian or plastic fluids.'.' This latter classification includes most colloidal types of drilling muds. Two properties: plastic viscosity, un, and Bingharn yield value, Y,, are commonly used to define the flow characteristics of a plastic fluid. These are commonly obtained with multispeed viscosimeters such as the Fann V-G meter.3 Normally these measurements are obtained at some surface temperature, and are not corrected to circulating temperatures for calculation purposes. This may result in considerable error, particularly in the laminar flow calculations which comnlonly apply to the drill pipe-borehole annulus. The purpose of this study was to investigate the effect of temperature on the flow properties of some water-base muds. A laboratory model Fann V-G meter was used for measurement of viscosities, yield values and gel strengths. An aluminum water jacket with O-ring seals was machined to fit around the mud cup of the Fann meter. All mud samples were prepared by thorough mixing in a Hobart mixer. Viscosity and gel strength measurements were made with the Fann meter using standard procedures. Flow properties of muds were studied at 80, 120, 160 and 180°F. The compositions of the test samples are given in Table 1. The typical effect of temperature on the flow properties of these drilling muds is illustrated by Fig. 1. It was found that plastic viscosity and apparent viscosity decreased with an increase of temperature. However, the curves were not linear, and did not appear to follow any definite trends or patterns. Yield point data showed much more scattering.' Since a usable method for predicting drilling mud flow behavior with temperature was desired, an attempt was made to find a simple relationship between these variables. The basic approach used by Havenaars for predicting the same effect on turbulent viscosity resulted in Fig. 2, which shows that

By J. S. Browning

The pegmatites of the Kings Mountain-Lincolnton, N. C., area constitute the largest known domestic reserve of beryl and spodumene. The reserve is estimated to contain 90 million tons of pegmatic material with 1,280,000 tons of recoverable Li2O (lithia) as spodumene.1 The pegmatites also contain 0.4 to 0.5 pct beryl disseminated throughout the orebodies. The pegmatites may contain a potential reserve of 240,000 tons beryl, equivalent to approximately 34,000 tons of BeO. Different flotation methods for separating beryl from feldspar or quartz, or both, have been developed by various investigators.2,3,4,5,6,7 On the other hand, published information is limited on concentration of spodumene-beryl ores. As the response of beryl and spodumene to flotation is essentially the same, a successful separation of the two minerals depends upon use of a selective depressant or a selective collector for one of the minerals.

Jan 7, 1961

By Walter O. Snelling

Continuation of the discussion of the paper of WaltER o. SnelLIng, presented at the New York and San Francisco meetings, February and September, 1915, respectively, and printed in Bulletin No. 100, April, 1915, pp. 695 to 704 and Trans., li, pp. 657 to 671. A. C. McLaUghlin, San Francisco, Ca1.—It seems to me that Mr. Snelling's work, if it is what it appears to be, is one of the most important contributions to petroleum technology that has been brought out in the last 25 years. If his end products are what they seem to be, he has made. a discovery, which, in my judgment, will revolutionize the petroleum industry. As to industrially carrying out these processes I do not think there is the slightest difficulty, for I have had some work recently where crude oils were handled successfully at a temperature of 750" F, and pressure of 750 lb. per square inch. William A. WillIams, San francisco, Ca1.—What metal did you use, Mr. McLaughlin? A. C. McLauGHILIN.—Ordinaly seamless tubing, extra strong. William A. Williams.—Tests were made in Dr. Rittman's experimental plant at Pittsburgh, upon samples of residuum furnished by Mr. Bell, the residuum being the remainder of the crude oil after the lighter fractions had been removed. After the material had been run through Dr. Bittman's plant, yields of from 43 to 58 per cent. of material, boiling under 150" C. were obtained. The distillate had a peculiar odor, due to the presence of benzene, toluene, and other unsaturated hydrocarbons. W. N. Best, New York, N. Y.—What is the difference between the Rittman and the Snelling process or system? William A. Williams.—he fundamental difference is that reactions take place under relatively higher temperatures and pressures and with none of the oil present in its original or liquid state, while the reactions secured by Mr. Snelling and other investigators have been from the liquids in the presence of some vapors. Under such conditions as Mr. Snelling operates, the temperatures and pressures used are limited and the flexibility in the control of these variables is extremely limited when compared with the Rittman process.

Jan 1, 1916

By W. D. Lowry

As most of the industrial activity of Oregon is centered in the Portland area, the foundries there consume the bulk of the foundry sand produced in Oregon. Although a number of the larger towns scattered throughout the state have gray-iron foundries, the sand used by most of them is of local origin. The yearly consumption of foundry sand of all types for the past few war years in Oregon is estimated to have been approximately 40,000 tons valued at about $285,000, of which an estimated 18,000 tons was shipped in from the Ottawa, Ill., district for use largely by the steel foundries. Until 1945 much of the silica sand consumed by the steel foundries in the Pacific Northwest, approximately 50,000 tons in 1944, came from Ottawa, Ill. and surrounding regions. Although some silica sand was shipped in from Belgium in the past, none is known to have been imported in recent years. Early in 1945, a very promising high-grade silica sand being produced near Eugene, Oregon, was introduced, and all but two of the Portland steel foundries are using this new sand. Until a few years ago, the search for good local (Oregon) foundry sands was carried on largely by the foundry supply houses. Recently the Oregon Department of Geology and Mineral Industries has investigated a number of deposits and has carried on and fostered research on the most bromising deposit near Eugene, about 120 miles south of Portland. High-grade silica foundry sand from this deposit is now being marketed in Oregon, Washington, and British Columbia. The Eugene sand is one of the very few outstanding western steel-foundry sands. Field investigations by the Oregon Department show that there are relatively few deposits of sand in Oregon suitable for foundry use. A knowledge of the geology of the state makes this readily understandable. The only major primary sources of the quartz present in sandstones in Oregon are the intrusive masses of granite, granodiorite, and quartz diorite of late Jurassic or early Cretaceous age found in the Siskiyou Mountains of southwestern Oregon, a part of the old Klamath Mountain highland, and in the Blue Mountains of northeastern Oregon. Transportation militates against the development of any possible deposits of foundry sand found east of the Cascade Mountains in central and eastern Oregon because few railroads traverse that area. East of the Cascades, which separate western from eastern Oregon, many of the older sediments of Paleozoic and Mesozoic age have either been metamorphosed or contain much volcanic eruptive material, and even if some of the Mesozoic sediments are highly quartzose in places, they are in relatively inaccessible areas. All the Tertiary sediments there are of continental origin and contain much ash and other volcanic debris, for there was great volcanic activity during much of that period. In western Oregon much the same is true of the Paleozoic and Mesozoic rocks

Jan 1, 1948

By W. D. Lowry

As most of the industrial activity of Oregon is centered in the Portland area, the foundries there consume the bulk of the foundry sand produced in Oregon. Although a number of the larger towns scattered throughout the state have gray-iron foundries, the sand used by most of them is of local origin. The yearly consumption of foundry sand of all types for the past few war years in Oregon is estimated to have been approximately 40,000 tons valued at about $285,000, of which an estimated 18,000 tons was shipped in from the Ottawa, Ill., district for use largely by the steel foundries. Until 1945 much of the silica sand consumed by the steel foundries in the Pacific Northwest, approximately 50,000 tons in 1944, came from Ottawa, Ill. and surrounding regions. Although some silica sand was shipped in from Belgium in the past, none is known to have been imported in recent years. Early in 1945, a very promising high-grade silica sand being produced near Eugene, Oregon, was introduced, and all but two of the Portland steel foundries are using this new sand. Until a few years ago, the search for good local (Oregon) foundry sands was carried on largely by the foundry supply houses. Recently the Oregon Department of Geology and Mineral Industries has investigated a number of deposits and has carried on and fostered research on the most bromising deposit near Eugene, about 120 miles south of Portland. High-grade silica foundry sand from this deposit is now being marketed in Oregon, Washington, and British Columbia. The Eugene sand is one of the very few outstanding western steel-foundry sands. Field investigations by the Oregon Department show that there are relatively few deposits of sand in Oregon suitable for foundry use. A knowledge of the geology of the state makes this readily understandable. The only major primary sources of the quartz present in sandstones in Oregon are the intrusive masses of granite, granodiorite, and quartz diorite of late Jurassic or early Cretaceous age found in the Siskiyou Mountains of southwestern Oregon, a part of the old Klamath Mountain highland, and in the Blue Mountains of northeastern Oregon. Transportation militates against the development of any possible deposits of foundry sand found east of the Cascade Mountains in central and eastern Oregon because few railroads traverse that area. East of the Cascades, which separate western from eastern Oregon, many of the older sediments of Paleozoic and Mesozoic age have either been metamorphosed or contain much volcanic eruptive material, and even if some of the Mesozoic sediments are highly quartzose in places, they are in relatively inaccessible areas. All the Tertiary sediments there are of continental origin and contain much ash and other volcanic debris, for there was great volcanic activity during much of that period. In western Oregon much the same is true of the Paleozoic and Mesozoic rocks

Jan 1, 1948

By D. L. Harris

Chemical upgrading testwork on Stillwater chomite concentrate shows that reduction roasting and leaching (sulfuric acid and/or ferric sulfate) can provide upgraded feed to ferrochromium furnaces for making upgraded ferrochromium. Two-stage reduction smelting in electric arc furnaces can make upgraded ferrochromium also. Sulfating roasts and leaching (acid and/or water) results using gaseous SO2—SO3 or solid ammonium sulfate were not satisfactory for upgrading chromite. Chemical upgrading of domestic Stillwater (Montana) chromite has been considered at various times1'2' to provide a material with higher chromium to iron ratio, more like foreign high grade ore, for the production of standard grade ferrochromium. Physical bene-ficiation of Stillwater chromite ore can provide a ratio, Cr/Fe, no higher than the ratio in the chromite mineral, which is approximately 1.7. For comparison the analyses of a foreign metallurgical grade chromite ore, a high grade electrostatic process Stillwater concentrate and a stockpile concentrate from the Stillwater ore are noted in Table I. Single stage smelting of the high grade foreign ore with a ratio, Cr/Fe, of 3.37 can provide a ferrochromium of over 65 pct chromium content. Similar smelting of the Stillwater concentrate with a ratio of 1.7 can provide a ferrochromium of 50 to 55 pct chromium content.' It has been demonstrated on a pilot plant scale that chemically upgraded Stillwater chromite having a ratio, Cr/Fe, of 3.0 also can be smelted to provide a ferrochromium containing over 65 pct chromium.5 Two major considerations for an upgrading process are the ratio, Cr/Fe, in the product and the chromium recovery. A minimum ratio, Cr/Fe, of 3.0 is required in the product but for economic reasons a higher ratio is desirable for blending purposes as long as the recovery is satisfactory. Data from different kinds of chemical upgrading testwork are presented in this report. Some of the testwork was conducted to make a product which was not intended to be feed for ferrochrome smelting, but the data are considered pertinent to chemical upgrading. Results reported by others are noted also for comparison. WORK REPORTED BY OTHERS The U. S. Bureau of Mines has contributed much to the literature on chemical upgrading of chromite and a summary is given in Table 11. Reduction roasting and acid leaching were reported by Boericke and Bangert,1 by Lloyd and Gorst, et a1,2 and by Boericke3 to demonstrate very good success on a laboratory scale and only fair success in pilot plant tests for Stillwater (Benbow) concentrates. This work included basic studies on thermodynamic properties to explain the reduction and leaching results. Canadian workers, Downes and Morgan,9 have reported experimental success in upgrading a low grade Bird River chromite, similar to Stillwater material by the same process. Russian workers1' have noted results on reduction tests of high grade chromite which may apply to low grade ores and which help in understanding the reduction process. The use of flux additives in the reduction process was an innovation of their work. The Canadian workers9 also reported other kinds of experiments, including autoclave leaching of the chromite in a limited amount of sulfuric acid. An insoluble basic chromium sulfate was formed and separated from soluble iron, magnesium, and aluminum sulfates to provide an upgraded material. U.S. Bureau of Mines workers, Lloyd, Rosenbzum, Home and Davis,' reported on autoclave leaching of Benbow concentrates as a means of obtaining chromium alum for electrolysis. This last work required selective crystallization of alum to separate iron from chromium. Chloridizing roasting of Benbow and Mouat concentrates has been reported by Hunter and Banning6 and others8 to show that the iron chloride could be volatilized from the chromite to provide upgraded residues.

Jan 1, 1964

By Tracy Jarrett

In 14-karat gold alloys, as in 10-karat gold alloys,3 the addition of such metals as zinc, nickel, copper and silver produces a wide range of physical and chemical proper-ties such as color, hardness, corrosion resist-ance and melting points. These important factors made gold alloys desirable in the optical work and for jewelry. In 14-karat gold alloys, as well as in 10-karat or 12-karat, it is possible to have two golds of the same color, one of which will corrode more than the other, although it may be harder. Some of these alloys have been investigated by F. E. Carter,1 E. M. Wise,5 and L. Sterner Rainer.4 In this group of alloys the gold content of 58.3 per cent (14-karat) was held constant, while the copper varied from 36 to 24 per cent. The balance of the alloy consisted of one, two, or three of the metals silver, zinc, and nickel. All the alloys were melted in an induction furnace and cast into an ingot that meas-ured 3 by 1/4 by 3/4 in. The method of determining the melting points, color deter-minations and acid test have been discussed in previous papers by the author.2,3 It is necessary to use small test bars (Fig. r). The tensile bars were annealed at 1300°F. for 20 min. and then air-cooled. There being a very marked drop when the yield point was reached, "the drop of the beam" method was used in determining the yield point.

Jan 1, 1940

By Arthur F. Wendt

In the manufacture of charcoal-blooms, washing or cleansing of the ore from adhering gangue has been practiced for many years. A sluice-box is even to-day used for that purpose in the Southern Appalachian Mountains. For the Lake Champlain bloomaries hard magnetic ores are crushed with stamps and then sluiced or jigged in hand-jigs. The stamps used in the Lake Champlain region are of the most primitive kind. They consist of a trip-hammer, dropping on a perforated cast-iron plate, through which the crushed ore escapes. Only friable rock can thus be successfully treated. To render the raw ore friable, a calcining or burning in piles on a bed of cordwood is resorted to. An expense of 35 cents per ton of crude rock treated is thus incurred. The crushed ore is shovelled or otherwise fed into jigs without previous sizing, except such as is incidental to crushing through the perforated bottom of the stamping-machine. In jigging this ore, it is allowed to pass through the bedding into the "hutch." The tailings are scraped off and wasted. They contain a large percentage of fine ore. In many instances, this is regained by subsequent sluicing. Such was the condition of the industry, when the writer's attention was first called to it in 1882. No attempt had been made to introduce into thiS branch of ore-dressing the notable improvements adopted in concentrating the ores of other metals. The result of the writer's investigations was the building in 1882 of the "Crown Point Separator." At the Crown Point Mines, N. Y., lean ore unfit for the blastfurnace (containing less than 331/3 per cent. of iron), was concentrated and used in the bloomary connected with the mines. The ore was burned here as elsewhere, and treated as described. The plant designed by the writer for Crown Point, is nearly a counterpart of that since erected by Messrs. Copeland and Bacon, contractors, for the Theal mine, Putnam County, New York, which is illustrated by the accompanying plate. The only difference is in

Jan 1, 1885

IT may perhaps seem to you that I have deviated from sequence by having entered into the narration of this arrangement of the bellows, but, although they are not furnaces or vessels for containing the melts, they are essential agents for bringing to port the bark of your labors. Returning to our regular pathway, and supposing that, besides making the moulds, you have melted and cast not only statues and bells but also guns, it is true that a certain procedure is required in order to finish them. For this you should have the moulds full, and they should have come out very well, for in truth reason does not allow that they turn out otherwise for one who uses precaution. [II2V] Then you have taken your casting from the pit and have freed it of clay. Since I have told you nothing beyond this, do not be dismayed if you see the castings so rough and in a form that scarcely shows what they really are, for I wish to open up part of the way into the great labor of finishing them so that it may seem to you that you have been somewhat helped by me. Therefore, when it is a gun, first see that the iron spindle that has been placed in the middle of the core is taken out. You can do this easily by striking the heel of the core, especially if the spindle had first been covered with ashes, hemp, or a little rope. Then saw off the feeding head above the mouth, using either a dun steel saw with tiny straight teeth that has been tempered with oil or some other fat, or a hay sickle whose edge is gently hit by a little hammer. Then have the clay that is attached to the curls or other bronze parts lifted away with a chisel. Then with a scouring brush and water uncover the emblems, coats of arms, borders, and cornices that you made as ornaments. Striking it with a hammer, push inwards every superfluous bit of bronze. Finally, having cleaned the bronze by washing, scraping, and cutting away every bit of clay, strike its surfaces gently with a large hammer and thus make it very smooth. Likewise finish the mouth and all its cornices as exactly and completely as possible with files and any other instrument that serves best. Then take a long, powerful tool that has some steel on the point, made like a chisel and somewhat bent, or with three points like the iron blade

Jan 1, 1942

By N. Van Wingen

EFFective sand permeabilities can be ascertained from core analysis if the laboratory data are compensated to allow for the presence of connate or residual water. Such adjustments can be made by applying empirically derived correction factors. Effective sand permeabilities can be estimated also from analytical studies of field depth-pressure measurements. In one method the time rate of pressure build-up after a well is shut in from steady-state flow is required, and in the other the direct measurement of a steady-state rate of flow and the corresponding equilibrium pressure. The results of the investigation discussed in this paper demonstrate that these methods for determining mean effective sand permeabilities can be correlated. Introduction In recent years many investigators have demonstrated the practical value of an accurate knowledge of the physical and dynamical characteristics of reservoir sands containing oil and gas. Of these factors, which serve to completely define a porous medium as a container or carrier of fluids, the dynamical characteristics are of particular interest to the production engineer because they afford a direct measure of the rate at which the oil or gas content of a reservoir will become available. The constant that defines dynamically the porous medium as the carrier of a homogeneous fluid in viscous motion is the "permeability." Coke-analysis Method The generally accepted practice in com-piling permeability data has been to analyze in the laboratory core samples taken in the course of drilling through the productive horizon, and to obtain the mean measure of the productive ability or permeability for the interval open to production by graphical integration of the permeability profile. An average permeability ascertained in this manner, however, is useful to the production engineer only for comparisons of wells drilled in the same horizon, as permeabilities determined in the laboratory are measures of only the ability of a porous medium to transmit a single fluid. As a result of many investigations, it has been shown, however, that under actual reservoir conditions water is coexistent with the petroleum and that its presence greatly reduces the permeability of the sand to oil. Empirical relationships showing the effect of the presence of any immiscible fluid A (such as water) in a porous medium on the permeability of the medium to a fluid B (such as oil) have been established separately by Hassler,1 Dunlap,2 and the writer (Fig. I),3 so that the average specific or dry-core permeability as determined in the laboratory can be corrected to give the true measure of the ability of the horizon penetrated to transmit oil, provided the percentage of pore space occupied by connate water is known accurately.

Jan 1, 1942

By N. Van Wingen

EFFective sand permeabilities can be ascertained from core analysis if the laboratory data are compensated to allow for the presence of connate or residual water. Such adjustments can be made by applying empirically derived correction factors. Effective sand permeabilities can be estimated also from analytical studies of field depth-pressure measurements. In one method the time rate of pressure build-up after a well is shut in from steady-state flow is required, and in the other the direct measurement of a steady-state rate of flow and the corresponding equilibrium pressure. The results of the investigation discussed in this paper demonstrate that these methods for determining mean effective sand permeabilities can be correlated. Introduction In recent years many investigators have demonstrated the practical value of an accurate knowledge of the physical and dynamical characteristics of reservoir sands containing oil and gas. Of these factors, which serve to completely define a porous medium as a container or carrier of fluids, the dynamical characteristics are of particular interest to the production engineer because they afford a direct measure of the rate at which the oil or gas content of a reservoir will become available. The constant that defines dynamically the porous medium as the carrier of a homogeneous fluid in viscous motion is the "permeability." Coke-analysis Method The generally accepted practice in com-piling permeability data has been to analyze in the laboratory core samples taken in the course of drilling through the productive horizon, and to obtain the mean measure of the productive ability or permeability for the interval open to production by graphical integration of the permeability profile. An average permeability ascertained in this manner, however, is useful to the production engineer only for comparisons of wells drilled in the same horizon, as permeabilities determined in the laboratory are measures of only the ability of a porous medium to transmit a single fluid. As a result of many investigations, it has been shown, however, that under actual reservoir conditions water is coexistent with the petroleum and that its presence greatly reduces the permeability of the sand to oil. Empirical relationships showing the effect of the presence of any immiscible fluid A (such as water) in a porous medium on the permeability of the medium to a fluid B (such as oil) have been established separately by Hassler,1 Dunlap,2 and the writer (Fig. I),3 so that the average specific or dry-core permeability as determined in the laboratory can be corrected to give the true measure of the ability of the horizon penetrated to transmit oil, provided the percentage of pore space occupied by connate water is known accurately.

Jan 1, 1942

W. E., RUDER, Schenectady, N. Y. (written discussion *).-Professor Howe, with characteristic thoroughness, has demonstrated that Professor Jeffries' "Reversed Inheritance" explanation of the case in question is contrary to fact, as shown by many previous observers. Since the photographs were my own, I feel it my duty to say a few words in discussion. In the first place, it is to be noted that these photographs were of pressed powders, and although many of Professor Jeffries' original experiments were made from this kind of material, the nature of such a specimen must of necessity be different from that of the fused metal, although the same basic laws of grain growth may apply in both cases, certain factors, such as the rate of change, for example, are undoubtedly different in each case. That the 1000° C. grain is a natal grain is evident from its appearance contrasted with the more perfectly formed, though smaller, grains in the 1300° C. photograph. I am not sure that Professor Howe's explanation of the formation of this grain is necessarily the correct one, although it agrees with. Stead and Carpenter's results. I am inclined to think that this grain may have been formed on heating, because I have been able to produce grains of the shape and magnitude of Stead and Carpenter's grains by heating to 850° C. pure electrolytic iron, which has been subjected to a strain gradient. On reheating to 1300° C., the mobility being so much greater, the individual crystals had time for unhampered re-arrangement and growth after their second refinement on passing Ac3, so that we have in this case a true fused metal condition in which the individual crystals are arranged in true equiaxed grains of a size consistent with their high temperature anneal. In this case the grains are equiaxed, inheriting none of the columnar tendencies of the previous grain, because they were not affected by any strain gradient, except possibly some accidental local gradients. It seems to me that the introduction of pressed powders into the discussion of grain growth, where allotropic changes take place, unnecessarily complicates an already complicated problem.

Jan 1, 1918

By Geo Ashley

THE following paper is intended to be suggestive only, and to open the way for discussion and further observation. Its preparation was requested only two days before the time limit set for the submission of the papers comprising this symposium. Thus no time existed for detailed studies so it is largely a memorandum of such facts as have come incidentally to the notice of the writer in the study of coal in the field. The field study of sulfur in coal has received very little special attention or description from coal students. The presence of sulfur concretions is noted in hundreds of descriptions, and certain benches of a coal bed may be described as "sulfury" or the presence and position of sulfur bands may be noted in coal sections in connection with sampling. It may be accepted that some sulfur is present in all coal. The amount varies greatly in different regions, in different beds, and in the same bed in different areas. The anthracite of Rhode Island comes the nearest of any coal known to the writer of being free from sulfur, several analyses of that coal showing less than 0.1 per cent. Subbituminous coals in Colorado in a few places have close to 0.2 per cent. of sulfur on the dry-coal basis and in other states subbituminous coals approach this lower limit. Bituminous coals seldom run under 0.4 per cent. of sulfur on the dry basis, though in a few places dry bituminous coals in Colorado and Washington have between 0.3 and 0.4 per cent. The better known bituminous coals have almost everywhere over 0.4 per cent. The best of the Pocahontas and New River coals run close to 0.4 per cent., but there is very little commercial coal in Pennsylvania, Ohio, Indiana, Illinois, Kentucky, or the other states that runs under 0.5 per cent. on the dry basis. From these minimum figures, the amount will range up to 5 or 6 per cent. or higher if visible sulfur is not excluded. It must be remembered that the usual -analysis of a coal bed is not intended to give the total proportion of sulfur in the bed but the amount in the coal after the removal of the more obvious and larger sulfur masses.

Jan 9, 1919

By J. L. SILSBEE

THE existence of large saline deposits in that flat arid basin, known as the Great Salt Lake Desert, has long been recognized, but the extent and great commercial value of these deposits has not been generally appreciated. That a very considerable interest has recently developed is indicated by the fact that about 263 prospecting permits-each covering about 2560 acres of land in this Desert-have been issued under the Potash Leasing Act (Act of 0ct. 2, 1917-40 Stat. 297), and patents granted on approximately 40,000 acres. It is reported that patents and leases have, or will be applied for on an additional 80,000 acres in the basin. , Tests have been made on probably less than 10 per cent. of the total area of the basin, but these have proved a practically unlimited supply of brine available -sufficient, probably, to. furnish the potassium and magnesium chloride requirements of this country for at least a hundred years.

Jan 1, 1925

By B. R. Palmer, M. C. Fuerstenau

Oxide and silicates respond to flotation with a large number of anionic collectors. These include carboxylates (fatty acids), sulfonates, alkyl sulfates, and certain chelating agents. In contrast to sulfide mineral flotation, relatively long-chained collectors (generally longer than 10 carbons) are required to effect flotation of this group of minerals. The structural formulas of these various anionic collectors are presented in Table 1. Formulas and solubilities of various fatty acids are presented in Table 2. These solubilities are those of the dissolved and undissociated species of the acid, e.g. oleic acid, HOl(aq). Of the compounds listed, oleic acid and abietic acid, which IS a major constituent of talloel, are used most commonly in commercial applications. The usage of these two collectors is related to cost and effectiveness. In addition to their high molecular weights, oleic acid contains a double bond in its hydrocarbon chain, while abietic acid is comprised of aromatic rings containing double bonds. The presence of double bonds increases solubility significantly over that of saturated homologues. Stability of metal-collectors assumes a most significant role in these systems, and the solubility products of various metal carboxylates and sulfonates are listed in Tables 3, 4 and 5. In addition to these properties, strength of the acids of these various anionic collectors is also important. The carboxylic and hydroxamic acids are weak acids whereas sulfonic and alkyl sulfuric acids are strong acids. All of the carboxylic acids fall in the range of pK = 4.7 ± 0.5 ([2]); the pK of hydroxamic acid is around 9 ([3]); and the pK of sulfonic acid is about 1.5 ([4]).

Jan 1, 1976

By B. D. Cullity, O. P. Puri

The magnetostrictia of nickel after increasing amounts of plastic elongation was measured at field strengths up to 1500 oe. In addition, the residual stress was measured by means of X-ray line shifts. The observed decrease in magnetostriction following plastic strain is shown to be associated with residual compressive stress. If a metal bar, whose longitudinal axis is taken as the x direction, is plastically elongated in the x direction and then unloaded, X-ray diffraction measurements will indicate the presence of a residual compressive macrostress 0%. However, stress measurement by means of mechanical relaxation does not reveal any macrostress. In a previous paper1 the fictitious macrostress indicated by X-rays was ascribed to a particular distribution of micro-stress, namely, one in which the bulk of the material was stressed more or less uniformly in compression and a very small portion in tension. It was shown that this distribution would account for Neurath's measurements2 of magnetic losses in silicon steel, because of the effect of residual stress on magnetostriction. The present paper is concerned directly with magnetostriction, in nickel, and with the effect on magnetostriction of the residual stress created by plastic elongation. The residual stress was determined by measurements of X-ray line shifts. MATERIAL AND METHODS Commercially pure "A" nickel was investigated. Its nominal composition, in weight percent, is 99.4 Ni + Co, 0.2 Mn, 0.15 Fe, 0.1 Cu, 0.1 C, 0.05 Si, and 0.005 S. Magnetostriction was measured by means of SR-4 electrical-resistance strain gages mounted on specimens 1/4 in. sq and 8 in. long. Magnetic fields up to about 1500 ce were provided by a multilayer, non-cooled solenoid. A considerable amount of heat was developed at the higher field strengths, and, to avoid errors due to changes in the specimen temperature, the following procedure was adopted. Each measurement of the magnetostriction X at a particular field strength H was preceded by demagnetization and an adjustment of the strain indicator to zero; the field H was then quickly switched on and the strain read immediately. Curves of ? vs H were flat for field strengths above about 750 oe for all specimens, and this constant value of X was accordingly taken as the saturation magnetostriction ?s The X-ray measurements of residual stress were made with a Norelco diffractometer on specimens cut from flat bars 1 1/4 in. wide, 1/8 in. thick, and 12 in. long. These measurements were confined to lattice planes parallel to the surface of the specimen. Two reflections were studied: the 311 CrKß line at 28 = 157 deg, and the 420 CuKal line at 28 = 155 deg. The line centers were determined by fitting a parabola to the peak of the line, as suggested by Ogilvie3 and as modified by Koistinen and Marburger.4 The CuKa doublet from the plastically elongated specimens was first resolved by the Rachinger method5. All X-ray measurements were made by counting at fixed angular positions. RESULTS The results of the magnetostriction measurements are shown in Fig. 1 and Table 1. The magnitude of

Jan 1, 1963