Search Documents

By Charles Weaver

DURING the past few years there has been considerable activity in prospecting for oil and gas in several parts of western Washington. From time to time seepages of oil or emanations of gas have been reported from various places. Several companies have been organized for the purpose of drilling, but only a part of these have actually begun operations. In certain localities very small seepages of oil occur, but up to the present time no oil or gas in commercial quantities has been obtained. In order to determine the conditions which may be favorable or unfavorable 'to the occurrence of petroleum it becomes necessary to know the character and extent of the geological formations in which such deposits might occur. In other regions where producing wells have been developed it is possible to know what formations contain the oil mind what structural conditions influence its concentration in reservoirs or zones. It is usually possible to determine those strata which contained the a materials from which the petroleum may have been derived and also the position and distribution of the more porous sandstone belts into which it may have collected. Detailed stratigraphic surveys, may even determine the depth at, which a certain known oil-bearing zone may be tapped at any particular place. It is also possible to recognize those formations which are presumably barren of oil, as well as those which are absolutely so.

Jan 7, 1915

By H. E. Stamm, H. H. Spain, R. C. Rumble

This paper presents a reservoir analyzer study of the performance of the Woodbine formation in the East Texas basin. The study was made possible by the compilation of available information on the configuration. thickness and the pressure drawdown of the formation. The investigation was made of the pressure variations in the basin incident to production from the several Woodbine reservoirs. In addition, the apparent compressibility of Woodbine water was evaluated so that the potential water yield of the formation could be determined. The distribution of permeability of the Woodbine sand and the interference between producing areas were also investigated. In conjunction with this basic study of the Woodbine sand, an acceptable match of the production-pressure relationship in the East Texas Field was established on the analyzer. INTRODUCTION When production is taken from a reservoir contiguous to an aquifer, the resultant pressure gradient causes a water influx into the reservoir. For some years it has been the practice to predict the performance of water drive reservoirs with mathematical equations that relate the water influx into reservoirs to their pressure behavior. A rigorous solution of these equations is quite complex: hence, the conventional method requires the simplifying assumptions that the formation have constant thickness, permeability and poiosity, and that it have a known and regular shape. It is necessary to use performance records of the reservoir in question to determine the equation constants that make the results of the mathematical calculations duplicate the reservoir history. The values of the constants determined in this manner sometimes differ so greatly from theoretical or measured values that the constants appear unreasonable. The equation constants comprise such factors as the thickness, porosity and permeability of the formation, and the viscosity and compressibility of water. Usually the thickness, porosity and viscosity are known within a reasonable degree of certainty. whereas the formation permeability and the water compressibility are known with considerably less certainty. Hence. permeability and compressibility values are arbitrarily selected that will make the mathematical equations duplicate the reservoir behavior. In many reservoir studies the value of the compressibility of water thus selected has exceeded the reported value by a factor of from severalfold to manyfold. Whether this excessive value results from the inadequacy of the mathematical approach to take into account the shape irregularities and the heterogeneities of the aquifer, or is due to some type of formation compaction and decrease of porosity has not been established. Because of the significance of the potential water yield of formations with reference not only to oil reservoirs but to water resources as well, it is very important that a representative value for the effective water compressibility be determined. One of the best known examples of a field for which it has been possible in the past to predict the future reservoir pressure is the East Texas Field. Until about 1943 it was possible by means of mathematical equations to duplicate past pressure behavior and to predict with a high degree of accuracy the reservoir pressure of the field. Since 1943, however, the calculated pressures have deviated progressively from the observed pressures to such a degree that in recent years, it has

Jan 1, 1951

By H. H. Spain, R. C. Rumble, H. E. Stamm

This paper presents a reservoir analyzer study of the performance of the Woodbine formation in the East Texas basin. The study was made possible by the compilation of available information on the configuration. thickness and the pressure drawdown of the formation. The investigation was made of the pressure variations in the basin incident to production from the several Woodbine reservoirs. In addition, the apparent compressibility of Woodbine water was evaluated so that the potential water yield of the formation could be determined. The distribution of permeability of the Woodbine sand and the interference between producing areas were also investigated. In conjunction with this basic study of the Woodbine sand, an acceptable match of the production-pressure relationship in the East Texas Field was established on the analyzer. INTRODUCTION When production is taken from a reservoir contiguous to an aquifer, the resultant pressure gradient causes a water influx into the reservoir. For some years it has been the practice to predict the performance of water drive reservoirs with mathematical equations that relate the water influx into reservoirs to their pressure behavior. A rigorous solution of these equations is quite complex: hence, the conventional method requires the simplifying assumptions that the formation have constant thickness, permeability and poiosity, and that it have a known and regular shape. It is necessary to use performance records of the reservoir in question to determine the equation constants that make the results of the mathematical calculations duplicate the reservoir history. The values of the constants determined in this manner sometimes differ so greatly from theoretical or measured values that the constants appear unreasonable. The equation constants comprise such factors as the thickness, porosity and permeability of the formation, and the viscosity and compressibility of water. Usually the thickness, porosity and viscosity are known within a reasonable degree of certainty. whereas the formation permeability and the water compressibility are known with considerably less certainty. Hence. permeability and compressibility values are arbitrarily selected that will make the mathematical equations duplicate the reservoir behavior. In many reservoir studies the value of the compressibility of water thus selected has exceeded the reported value by a factor of from severalfold to manyfold. Whether this excessive value results from the inadequacy of the mathematical approach to take into account the shape irregularities and the heterogeneities of the aquifer, or is due to some type of formation compaction and decrease of porosity has not been established. Because of the significance of the potential water yield of formations with reference not only to oil reservoirs but to water resources as well, it is very important that a representative value for the effective water compressibility be determined. One of the best known examples of a field for which it has been possible in the past to predict the future reservoir pressure is the East Texas Field. Until about 1943 it was possible by means of mathematical equations to duplicate past pressure behavior and to predict with a high degree of accuracy the reservoir pressure of the field. Since 1943, however, the calculated pressures have deviated progressively from the observed pressures to such a degree that in recent years, it has

Jan 1, 1951

By P. H. Mell

The little village, from which this formation receives its name, is situated on a bluff of the Alabama River, 175 feet above water level. This bluff is a portion of high table land that begins in the western portion of Choctaw and extends through Clarke and Monroe counties. We find points on this ridge more than 100 feet higher than Tuscaloosa, and nearly as high as the Tennessee River at Tuscumbia. Through this the Alabama River cuts its way, exposing a beautiful cross-section of the strata, of which the accompanying sketch may give some idea. The fossils are found about 75 feet below the surface and 100 feet above the level of the river. There are seven distinct strata. 1. The lowest, extending from the water's edge up the bluff 80 feet, is a soft calcareous rock containing about 15 per cent. of carbonate of lime, with occasional specks of mica. In this a few Ostrea, Turritellæ, and Flustræ were found, but so friable as to fall to pieces when handled. 2. Next comes a stratum varying from 2 to 8 feet, consisting of

Jan 1, 1880

By J. W. Halley

THE effects of tin on steel have become increasingly important because of the necessity of using poorly detinned scrap, tin cans, and terne plate, in the open hearth. Since a tin can contains about 1.5 per cent tin, it would be possible to have up to 0.75 per cent tin in steel made with a 50 per cent scrap charge. In order to use tin-containing scrap, it is necessary to know the effect of tin on various grades of steel. The following investigation is by no means comprehensive but covers a number of steels in which tin content is important. PUBLISHED WORK A number of investigations of the effects of tin on rolling quality and physical properties have been published. It has been found that tin increases strength and hardness and reduces ductility and notched impact resistance. The decrease in ductility and notched impact resistance becomes more marked as the carbon decreases. McKimm1 found no change in Olsen ductility, Rockwell hardness, yield strength, tensile strength or elongation in cold-reduced strip containing up to 0.124 per cent tin. A tin content of 0.15 per cent gave difficulties in rolling and increased the hardness but 0.21 per cent tin showed no change in properties from material containing very little tin. No explanation of this contradiction is offered. Andrew and Peile2 investigated steels containing 0.01 to 0.25 per cent carbon and up to 0.63 per cent tin. They found an increase in tensile strength of from 100 to 200 lb. per sq. in. for each 0.01 per cent tin on normalized samples. The elongation and reduction of area were decreased and the notched impact resistance was reduced markedly. Quenched and drawn samples did not show embrittling if water-quenched from the draw temperature of 1148°F. (620°C.). They could find no evidence of tin under the microscope. Whitely and Braithwaite3 investigated the effect of tin on rail steel containing 0.55 to 0.06 per cent carbon. They found that 0.08 per cent tin caused a marked decrease in elongation, notched impact resistance and the degree of bend. The tensile strength was increased in some tests and not in others. Bolsover and Barraclough4 investigated the effect of tin up to 0.50 per cent on a 0.35 per cent carbon steel and on several alloy steels with from 0.30 to 0.40 per cent carbon. They found a comparatively uniform decrease in notched impact resistance with increasing tin on quenched and drawn samples. If the samples were quenched from the drawing temperature or reheated to the drawing temperature and quenched, the embrittling was much less severe. Steels containing molybdenum suffered much less embrittlement than other steels. EXPERIMENTAL WORK Effect of Tin on Low-carbon Rimmed Steel Increasing quantities of tin were added to four ingots of a heat of the following ladle analysis: carbon, 0.08 per cent; manganese, 0.39; phosphorus, 0.009; sulphur, 0.025.

Jan 1, 1942

By J. R. Low, M. Gensamer, W. T. Lankford

THE problem of sheet metal formability is one which has received a vast amount of attention during recent years. In spite of the great amount of study and experimental work which has been devoted to this problem, many of its fundamental aspects are still not well understood. No generally satisfactory test has been developed which is capable of providing a reasonably adequate evaluation of sheet metal formability, particularly in borderline cases. Anomalies persistently arise in which a lot of supposedly satisfactory material exhibits excessive breakage when formed. This lack of suitable technological tests greatly hinders the design of new parts and the substitution of new materials in parts of existing design, frequently necessitating considerable costly trial and error experimentation on an actual production basis. When, at the beginning of World War II, it became apparent that mass production methods of forming would be required in the aircraft industry if the large numbers of military aircraft needed were to be supplied, renewed attention was focussed on the problem of sheet metal formability. It was widely recognized that the formability requirements placed on sheet metals had been steadily increasing in severity through the years, especially as greater and greater emphasis was placed on streamlined designs with the resultant freer application of doubly curved surfaces. The recent advent of several new high strength aluminum alloys of more limited formability than some of the older alloys also served to emphasize the need for new approaches to the problem. It seemed evident that progress in the technology of sheet metal forming would depend to a great extent on the development of more reliable criteria for the evaluation of formability. Although the problem is admittedly very complex, the most logical approach appeared to be through studies of the fundamental material properties of sheet metals, especially under complex stress conditions simulating those prevailing in actual forming operations. Most previous investigations have failed to make full use of existing knowledge of fundamental material properties, and in many instances have attempted correlations with properties which are now recognized as being ambiguous in nature. This investigation was undertaken, therefore, with the aim of developing methods for the study of the flow and fracture of sheet metals under combined stresses, and of making use of such methods as might be developed in

Jan 1, 1947

By A. N. Diehl

IT is the object of this paper (1) to deal with the elements in blast-furnace gas from the standpoint of their importance, and the part they are to play in future consumption, and (2) to give detailed information about the construction and operation of a plant designed among the first in this country for washing gas on a large scale.

Jan 5, 1914

By Will Coghill

FLOTATION has been so closely allied with the sulfide minerals and their early and associated oily reagents that the term "oil flotation" has erroneously been applied to the entire flotation process. Today, the term "chemical flotation" might be used to advantage. Flotation literature has dealt primarily with the removal of sulfides from non-sulfide gangues, and the separation of one sulfide from another. Now, the application of the process to the separation of nonsulfide minerals is coming to the fore; and from the standpoint of the number of commercial minerals involved, the flotation of nonsulfides offers the larger field. Here, soap or soap-forming substances, such as the fatty acids and their derivatives, are used; hence there may well be a subdivision of the chemical flotation process called "soap flotation." Early experimenters learned that it was easy to form a froth or foam that would carry a part or all of the ore charge over the lip of the flotation machine; but this could not be regarded as flotation because of the lack of selectivity. Doubtless soap was one of the first reagents tried, and doubtless it was rejected on account of its gangue-carrying properties. Now this same gangue-carrying ability makes soap an acceptable reagent, for we are dealing with that, which among sulfides, is considered "gan-gue." As in the flotation of sulfides, so in the flotation of nonsulfides, the selective flocculation of the mineral and the dispersion of the gangue are the first objectives. In fact, these two phenomena epitomize flotation. They depend upon the unlike surface properties of the respective miner-als; and as long as the components of an ore have unlike surface proper-ties, a separation is possible, at least in theory. Often in nonsulfide flotation it makes little difference which mineral floats and which is depressed; generally only a separation is sought.

Jan 1, 1932

By J. P. Kimball

INCIDENTAL to a description of the hytlrographical basin of the Quemahoning in Somerset county, Pa., as a coal-field, I have, without a personal survey of the whole county, taken the pains to collate a synopsis of' leading facts, so car as available, relating to its coal resources. This is here presented, in view of an interest in the subject, growing out of a nearly central traverse of the county, in common with the southern tier of counties of the State, west of Blue mountain, by a new trunk line of railway—the South Pennsylvania. The political east-and-west boundaries of Somerset county, Pa., following the bold topography of Allegheny mountain and Laurel hill, are in common with the east-and-west boundaries of the First Bituminous Coal-basin formed by these ridges respectively, except the southeastern townships which lie on the eastern slope of Allegheny mountain. The nearly parallel anticlinals of Negro mountain and the so-called Viaduct axis stratigraphically divide the basin into three sub-basins, which, in order from east to west, are known as follows, viz. : I. Berlin-Salisbury (Eustern) Sub-basin : Between Allegheny mountain and Negro mountain, embracing the Berlin section of Barren coal-measures, the Salisbury section of Upper Productive coal-measures, and the Meyersdale and Garrett sections of Lower Productive coal-measures. 11. Somerset (Middle) Sub-basin: Between Kegro mauntain and the Viaduct axis, so called from the viaduct on the Conemaugh river, which there crosses it; embracing the section of Lower Productive measures of Mineral Point and Casselman on Castlenlan river, and of Somerset. 111. Johnstown- Confluence (Western) Sub-basin: Between the Viaduct stratigraphical sub-axis (which is less strongly marked topograpically in Somerset county as a ridge than in Cambria county), and the Laurel Hill graud axis. The synclinal of this sub-basin is crossed by tile Conemaugh near Johnstown, and by the Castleman

Jan 1, 1884

By F. A. Emmerton

I have used for about two years, in the laboratory of the Joliet Steel Company, a rapid method for the determination of phosphorus in iron, steel, and ores, which possesses one or two features sufficiently novel to warrant description. In general, it is the method described by Mr. Benjamin B. Wright (Transactions, vol. x., p. 197), involving the precipitation of the phosphorus by means of molybdate solution, and its estimation in the yellow precipitate by reduction of the molybdic acid, and titration of the resulting oxide with a standardized permanganate solution, according to the principles laid down by Werncke (Fres, Zeit., vol. xiv., p. 1). In the use of this method, I had difficulty at first in obtaining a yellow precipitate of reasonably uniform composition. It is a well-known fact that, to secure this result, the conditions of precipitation must not vary. The principal condition is temperature; and acidity, concentration, proportion of nitrates and chlorides, and time, are important elements. I am aware that uniformity in these conditions has been obtained to a reasonable extent by many chemists,. so that they are enabled to use with success, methods based on the

Jan 1, 1887

By Cyril Smith

ALTHOUGH alloys of copper and silicon were examined several years ago,1 and their excellent mechanical properties were shown, it was not until C: B. Jacobs2 introduced manganese in small quantities to the alloys that they became of commercial importance. A few years ago The American Brass. Company took over the patents and commenced to manufacture the alloy under the name "Everdur." The present study of the constitution of the ternary system was undertaken in order to reach a fuller understanding of the behavior of the alloy. REVIEW OF PREVIOUS WORK ON, THE BINARY SYSTEMS There have been no papers published dealing with the constitution of the ternary system, although some tests of the mechanical properties have been described,3 which indicate that there is a change insolubility with temperature.

Jan 1, 1930

By P. F. Gnirk

Consideration is given to creater formation with shallow, contained, chemical explosions in rock masses which exhibit different inherent physical and mechanical properties as determined by standard laboratory techniques. The primary purpose is to determine whether or not a simple but useful generalized correlation can be established between explosive crater formation and one or more common rock properties. Such a correlation could be beneficial in predicting with some degree of reliability the size of a crater which could be expected in a particular rock type for a given input of explosive energy. A series of crater formation experiments employing constant weight charges of Gelex 2 explosive was conducted in five submembers of the taconite formation at the eastern end of the Mesabi Range in northeastern Minnesota. Five mechanical and physical properties-unconfined tensile and compressive strengths, Young's modulus of elasticity, longitudinal wave velocity, and density-were determined by conventional laboratory techniques using core samples from the taconite submembers. Although insufficient data were obtained to warrant the use of mathematical methods in the determination of empirical relationships, the results provided a fairly strong indication that with an increase in magnitude of any one of the five rock properties definite decreases in the optimum crater volume and surface area occur. Furthermore, for a constant explosive energy input, the presence of bedding planes and joint systems in a rock mass influences the formation of craters in such a manner as to increase the volume of rock broken substantially above that expected from the same rock mass without joint systems and, in particular, without bedding planes.

Jan 1, 1968

By Harold J. Bennett

A comprehensive knowledge of the availability of mineral resources to evaluate and assure a dependable supply is a prerequisite in establishing and maintaining a viable national economy. Since no nation is self-sufficient in all its mineral needs, its prosperity depends to a great degree upon its developing and maintaining an effective national minerals policy. This must be preceded by a systematic inventory of mineral resources that may be available to that nation. The U.S. Bureau of Mines is implementing a mineral deposit inventory program of domestic and foreign mineral occurrences, with initial emphasis on the domestic. In order to provide an in-depth appraisal of minerals availability, the approach includes not only realistic estimates of quantity and quality, but other essential factors such as costs, technology, environmental constraints, and development-time requirements. Analysis of this information provides usable relationships of quantity, price, time, and associated degrees of confidence of the occurrence of identifiable mineral resources. Keeping pace with a changing minerals industry and handling the large volume of information required in this undertaking demands that computer methods be employed.

Jan 1, 1977

By John C. Branner

Within a couple of years I have received many inquiries in regard to the manganese-mines of Brazil. These inquiries were doubtless directed to mc because I had lived and traveled in Brazil for more than eight years, and was therefore supposed to be pretty well acquainted with its geology and mineral resources. Somewhat to my chagrin, I not only knew nothing of manganese-mines in that country, but I had never before heard of the mineral having been found here in quantity, and I did not even know in what State the mines were located. The present summer found me in Brazil again, trying to finish up some of my early geological investigations along the northeast coast, and I have used the occasion to find out something about the manganese-deposits. Very little is known of these mines, even in Brazil. While at Pernambuco I was told that they were in the distant interior of the State of Bahia. In August I reached Bahia, and there I found out, concerning the mines and their geology, enough to be worth telling for the benefit of those interested in the mining or using of this mineral. Thus far, all the manganese-ore shipped from this State has come from two mines, the principal one of which is known as the Pedras Pretas mine. This was the first mine opened, is the best developed, and was the original discovery; the second one is on an adjoining tract, and the general geology and natural conditions are about the same in both. The Pedras Pretas mine is on the Nazareth-Amargosa railway, twenty-six kilometers west of the town of Nazareth, which is on tide-water, at the head of navigation, and is reached from the city of Bahia by a small side-wheel steamer that runs across the bay of Bahia and up the Rio Jaguaripe

Jan 1, 1900

By Ernest R. Lilley

While American scientific literature contains much information upon geologic conditions controlling the production of oil in Rumania, copper in Chile, and other fuel and metallic resources in many foreign countries, it is singularly lacking in data about the nonmetallics outside of the United States. Thus, though the United States is the outstanding market for European high-quality refined kaolin, and for the chinaware, porcelain, and other products of the European ceramics industries, American literature contains only the briefest references to the deposits from which the raw kaolin utilized is obtained. To the writer, to whom has come in the past year the opportunity of visiting a number of these deposits personally, they have proved of extreme interest both commercially and geologically. It is the latter phase that is discussed in this paper. The older and now largely crystalline rock areas of France, Germany, and other parts of western Europe contain numerous pegmatite dikes of which the upper portions have been subjected to surface weathering and kaolinization in much the same way as those of the eastern portion of the United States. Like the latter, the European pegmatite kaolins have long been known for their freedom from iron and other impurities offensive to the china and porcelain manufacturer. Unfortunately, they are also, like the American deposits, individually of small size and noted for their high costs of production. Deposits of sedimentary clay similar in many respects to the high-quality sedimentary kaolins of Georgia and South Carolina are known and worked, notably in southern Germany and in the Newton Abbott district of Devon and Dorset in England. In general, their relationship to the parent rock from which they were derived is more evident than in the United States and the individual deposits are of smaller areal extent and less regular in outline. While these deposits are of considerable economic importance they did not, because of their similarity to deposits in America, attract and hold the interest of the writer to the extent that several other types of deposits did. It is to the latter, which are so different from the kaolin

Jan 1, 1932

By C. M. Weld

Attention has been turned recently to the exploration and development of certain large blanket-deposits of brown iron-ore in Cuba. The most conspicuous of these to-day, and the one upon which the most light has been shed, is the Mayari deposit, situated about 15 miles south of Nipe bag. Here the Spanish-Aniericau Co. has sole control over 18,500 acres of ore-bearing lands, reported by its engineers to contain 500,000,000 tons of ore. The necessary plant and equipment, with docks and railways, is now under construction for the early marketing of this ore. A similar deposit, and undoubtedly the next to be exploited, is the ore-field at Moa bay, where from 13,000 to 15,000 acres of ore-lands, immediately adjacent to the shores of an excellent harbor, have been generously covered by numerous mining-claims, practically all controlled by four large interests;. This deposit is now estimated to contain approximately 350,000,000 tons, on the basis of dried ore ready for shipment, a figure which may be increased when the western limits of the ore-deposit have been more accurately defined. Other deposits of the same type, but smaller and less accessible, are those at Cubitas, situated from 12 to 15 miles north of Camaguey city,

Jan 1, 1910

By R. P. Rothwell

AT this our first meeting I beg to call the attention of the members of our Institute to what is certainly a question of the greatest possible importance to the industries we represent; and more particularly to the welfare of the coal and iron trades: I refer to the enormous waste of coal in mining and in its preparation for market, as now practised in our anthracite coal-fields. I t is a fact which many of you can certify to, that we are wasting fully me-half of all the coal in the veins we are now working, and there are cases, which might be mentioned where this proportion, immense as it is, has been greatly exceeded. The popular belief that our deposits of anthracite coal are "practically inexhaustible," is very far from being founded on facts. On the contrary, supposing the present rate of increase in the production to be maintained, it is probable that a maximum yield for our coal-fields would be attained in about fifteen years ; there are in fact some of our smaller basins where the principal veins are nearly exhausted and the production has already attained its maximum. There are others, again, where the depth attained-and it must be borne in mind that we commenced working at the surface outcrop moderate though it is (scarcely ever reaching eight hundred feet), has so increased the cost of mining as to imperil the capital invested, and though it requires but little foresight to predict the time when the difficulties of mining will be very considerably increased by reason of the greater depth, greater quantity of water, fire-damp, and other fruitful sources of cost, yet, ignoring these recognized facts, we continue to waste more than one-half of the coal where it is obtained with the least danger, expense, and trouble, that is, near the surface-either above water-level or at a moderate depth . below it. The inspection of almost any accurate mine map will satisfy you that, on an average, we leave fully one-third. of the coal in the ground as pillars to support the roof; in some places more than one-third thus remains, while it is very rare that less than one quarter is left. In almost every case this coal is absolutely lost, for it will very rarely pay to reopen gangways and lay roads to it after that portion of the mine has been abandoned. Is it necessary in all cases to support the roof, and where it is, may not some artificial

By E. S. Machlin, Morris Cohen

The martensite reaction in single crystals and polycrystals of 70 pct Fe-30 pct Ni alloys is shown to be autocatalytic in nature, producing bursts of transformation during cooling. The temperature of the first burst of transformation, called Mb, occurs below M, in these alloys. Experiments were devised to test the athermal embryo and strain embryo theories of martensite nucleation. The results indicate that internal strains, either within the virgin austenite or around existing martensitic plates, control the nucleation process in these alloys. Furthermore, the growth of martensitic plates is not limited by the attainment of an elastic balance with the austenitic matrix, but by the occurrence of plastic deformation at the martensite boundaries which interferes with the propagation mechanism. IN an investigation of the martensitic habit in single crystals of a 69 pct Fe-31 pct Ni alloy,' it was observed that about 25 pct of the austenite transformed during subatmospheric cooling within the time-interval of an audible click. This event proved quite spectacular: The shock wave sent out from the specimen freely suspended on a thread in the refrigerating liquid was occasionally sufficiently intense to shatter the Dewar container and to separate the toluene column in the immersed thermometer. The Present investigation was undertaken to determine- the kinetics and mechanism of this "burst" type of martensitic reaction. The analyses of the alloys studied are given in Table I. The composition of the single crystal specimens is designated by alloy A, while the polycrystal-line specimens were made of alloys B and C as noted in the text. The single crystals were prepared in a vacuum furnace, using a modified Bridgman technique. Most of these crystals were homogenized by holding for 24 hr at about 1300°C just after solidification. However, it may be emphasized here that the degree of homogenization was not a controlling factor in the subsequent experiments, inasmuch as specimens having different degrees of homogenization yielded the same results. All of the single crystals were fully austenitic as slowly cooled to room temperature. An illustration of the burst phenomenon is given in Fig. 1, which shows oscillograms of electrical resistivity and temperature vs. time during the continuous quenching of 1/16 in. wire specimens (alloy B) in a dry ice and acetone bath at —77°C. There are at least two observable bursts in this case, as indicated by the sharp decreases of resistance accompanying the sudden formation of substantial quantities of martensite. The thermal arrest during the quench probably corresponds to the larger burst. Usually the bursts are followed by more or less progressive transformation during continuous cooling. It will also be noted that the resistance continues to decrease after the specimen has reached the bath temperature. This isothermal change denotes the formation of martensite at constant temperature, and will be the subject of another paper. Examination of fiducial scratches on the surface of a transformed single crystal has shown2 that the scratches in adjoining nonparallel martensitic plates are usually bent in opposite directions, as though one plate forms in such a way as to relieve the matrix stresses set up by the adjacent plate. This, together with some of the results described in ref. 1, Table I. Compositions of Alloys Studied, in Percent Alloy Ni C N Mn Si P S Cr A 31±0.3 0.048 0.027 0.003 0.56 0.007 0.002 B 29.5±0.2 0.036 0.02 0.19 0.09 0.008 0.006 C 19.99 0.52 0.37 0.47 0.010 0.015 0.04 led to the tentative concept that a cooperative action exists which provides the impetus for much of the transformation that appears during the burst. The following series of experiments were performed in order to test this idea. Cooperative Nature of the Burst Two adjacent disks, Va in. thick x % in. diam, were cut from a single austenite crystal of alloy A using a jeweler's saw. One of the disks was then cut into 15 parts. Then 12 of the latter pieces and the second disk were austenitized (stress relieved) at 600°C for 30 min and water quenched to room temperature. The temperatures at which the first burst of transformation appeared were determined for

Jan 1, 1952

The early history of a country is linked with its topographic features. Mountains are barriers, rivers are avenues, the sea is a highway. The first Europeans to reach the northwestern corner of the American continent, now known as Alaska, came from Asia, for the Pacific Ocean provided an approach by means of the islands that like stepping-stones stretch far westward from the inhospitable shore of the mainland. The Russians crossed Siberia and explored the Arctic coast of Asia. In 1728 a band of Cossacks was driven by a storm eastward from Kamchatka, and landed in Norton Sound.* Others followed them, and settled on the islands and peninsulas of southeastern Alaska. The mountains guarding the coast discouraged any advance into the interior. Another range, the northern extension of the Rocky Mountains, barred the westward progress of the French voyageurs and the English fur-traders of the Hudson's Bay Company. After the Russians had obtained a foothold among the Indians, the viceroys of Mexico sent successive expeditions up the coast, such as that of Pérez in 1774 and of Heceta in 1775. If the English fur-traders had not interfered, the Spanish and Russian spheres of influence would have conflicted, and the contest for control might have ended in establishing a line of demarkation somewhere near the mouth of the Columbia river. The British navigator Captain James Cook landed near Sitka in 1778 while seeking a way by water to Hudson Bay. Fifteen years later his midshipman, George Vancouver, in command of another British expedition, surveyed the coast

Jan 1, 1932

By T. K. Matthews

Minerals are mined as a one-time crop, and the processing of one ton of ore results in there being one ton less to be recovered from the deposit. Although some minerals occur in greater abundance than others, they are to a greater or lesser degree exhaustible. Depletion Allowances One of the distinctive features of the mineral industries is the allowance for depletion. The depletion allowance is a much maligned and misunderstood principal of our tax structure. Although imperfect in design, it has nevertheless served as a constructive incentive for the development and expansion of the minerals industry.

Jan 1, 1969