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By J. H. Scaff, W. G. Pfann

The effects of impurities on the electrical properties of silicon are discussed in a companion paper by Messrs. Scaff, Theuerer, and Schumacher.' It was shown that an ingot of silicon which contained boron and phosphorus in certain concentrations consisted partly of p-silicon and partly of n-silicon2 and that the common boundary between these regions was the source of a photo-voltage. These features were ascribed to the segregation of boron and phosphorus during solidification of the ingot. Because of different rates of segregation the first portion of the ingot to freeze contained a molar excess of boron over phosphorus and hence was p-silicon. The last-solidified region contained a molar excess of phosphorus and was n-silicon. This paper is concerned with the microscopic examination of such ingots. The microstructures are rather unusual in certain respects and their study has helped to show how the segregation of minor elements modifies the electrical properties of silicon. The microstructures of ingots prepared from two lots of silicon, designated 1 and 2, will be described. These lots were obtained from the Electro Metallurgical Co. Both contain 99.8+ pct silicon, but they differ in impurity analysis. For each lot will be shown the microstruc-ture of a slowly cooled ingot, for which the time of solidification is 6 min., and that of a rapidly cooled ingot, for which the time of solidification is 2 min. The ingots were prepared from 45 g charges of silicon. When an alloy freezes a cored structure is generally produced because of insufficient diffusion to remove concentration differences established during freezing. As a result of coring the first portion of a crystal to freeze is usually poorer in solute than equilibrium requires, while the last material to solidify is richer. In a columnar grain, growth is principally unidirectional and coring can produce a concentration gradient along the entire grain. By carrying the picture of the coring process from a single grain to an entire ingot in which columnar grains are aligned more or less radially, one can easily see that a composition gradient could be established between the outside and center of the ingot. This, to a considerable extent, occurs during the solidification of a slowly cooled ingot of silicon. Slowly Cooled Ingot In slowly cooled ingots of both lots of silicon, columnar grains which are approximately radial in direction and longest at the top of the ingot enclose a region in which the shapes and align- ment of the grains are considerably less regular. The central region is last to solidify and contains cavities and inclusions. The sketch of Fig 1 illustrates some of these features, as well as others which will be described below. If a polished section of an ingot is etched in a mixture of 2 parts of 20 pct HF and 98 parts of HNO3 the p-n barrier becomes visible. The overall shape of the barrier in a slowly-cooled ingot is roughly oval, as may be seen in Fig 1. The proportion of n-silicon, that is, the region enclosed by the barrier, is considerably greater in ingots of lot 1 than in those of lot 2. A sample about 34 x 1/8 X 1/8 in. was cut from a slowly cooled ingot of lot 1 with its long direction extending from the top of the ingot to the porous region. Thus its upper half was psilicon, its lower half n-silicon. A longitudinal face was polished and etched in the acid mixture. The areas of interest are identified in Fig 2. A band of parallel markings extends across the sample in the columnar region. These striae are roughly parallel to the upper surface of the ingot and cross grain boundaries with only slight deviations. They are quite distinct in the n-silicon,

Jan 1, 1950

By B. B. Gottsberger

HAVE given considerable thought during the past year to the subject of licensing of engineers and par-ticularly to the position which the mining engineer should take on this question. I have found, however, that it is not a subject which yields much result for the thought expended on it. So far as any published record will show, mining engineers have been either ignorant of the extent to which the movement for the licensing of engineers has progressed or else indifferent to it. It is true that the Mining and Metallurgical Society of America, by a questionnaire sent out to its member-ship, did a great deal in calling this matter to the atten-tion of the mining profession, and so far as I know, the report of its committee, which analyzed the replies received, is the only published statement of the feelings and opinions of our branch of the engineering profes-sion. It is to be hoped that the conclusions shown by that report, namely, that mining engineers are almost unanimously opposed to the principle of licensing and consequently any legislation dealing with it, has received serious thought and that we are ready for an even more thorough consideration of the subject.

Jan 3, 1922

By Richard A. Busch, Roy L. Soderberg

Large, high, open stopes resulting from vertical crater retreat (VCR) and similar methods are usually filled with sand tailings to support the stope walls and make it possible to mine the pillars. The hydrostatic head resulting from these high stope fills demands extremely heavy bulkheads in the crosscuts to withstand the pres- sure. Occasionally, these bulkheads fail because there are no drains or the installed drains are inadequate. Costly flooding of the mine and loss of life result from these failures. With proper design of blanket drains and filters, the fill can be made failure-proof, requiring only a minimum bulkhead, designed specifically for zero water retention. The effectiveness of the blanket drains can be increased by laying perforated pipes on the bottom of the crosscut within the blanket drain. These drains can have a safety factor of 10 with minimal expense. When the water is properly drained, the hydrostatic pressure on the bulkhead is reduced to zero, leaving only the lateral pressure of the sand. This lateral pressure is partially dissipated by arching and shear against the crosscut walls and consolidation of the tailings as the water is drained. The bulkhead should be placed at least one cross-cut diameter back from the collar of the drawpoint.

Jan 1, 1983

By Leonard E. Wood, Yeghishe M. Avedissian

Knowledge of the basic properties of rocks-strength, structure, and permeability-is prerequisite for the success of foundation work for masonry dams, large bridge piers, and tunneling as well as for excavation in rock and special underground construction. Strength of engineering materials depends upon texture and structure as well as the environmental conditions to which they have been subjected. Failure in its widest sense implies the transition of a material from elastic to plastic state (yield strength), from continuous to discontinuous state (rupture strength). The compressive strength of a material such as rock is the stress at which a sample, loaded and unconfined at the sides, fails by rupture. Some of the external factors that control strength of rocks are the nature and type of stress, whether uniaxial or triaxial, compression, tension, or torsion. Another important factor is the rate of stressing-whether constant, impact, or gradually increasing. Of the internal factors, the effect of texture upon strength is obvious. Generally, fine-grained rocks have higher compressive strength than coarse-grained prototypes. Among metamorphic and igneous rocks those with better and higher degree of interlocking of their crystals are generally stronger than the ones with poor or lower degree of interlocking. In sedimentary rocks, the degree and type of cementation has a great influence upon their strength. Structurally, the existence of fissures, cracks, and seams of argillaceous or organic materials in a rock specimen will greatly reduce its strength. Because most rocks are characterized by bedding planes, laminations, or foliations, they are anisotropic in their physical properties and hence compressive strength depends on the orientation of the bedding planes to

Jan 1, 1972

1. Healthy and active Local Section organizations are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local. Sections should be recognized and stim¬ulated by appropriation of funds from the Institute's treasury; and these appropriations should be as large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should be based primarily on the extent of activities as reflected in the number and character, of meetings held and the attendance of the members at such meetings. 4. In making a request for funds for any year, the officers of a Local Section should submit a report on the printed form approved by the Directors at their meeting on November 19, 1937. 5. A . standing Committee on Local Section Appropriations, consisting of one past chairman of a Local Section, one member of the Institute's Executive Committee, and one member of the Finance Committee, shall be appointed by the President and shall pass upon requests for appropriations and authorize payments within bounds of the budget. The committee will be guided by the principles herein outlined, always having in mind the vital importance of healthy, active sections to the welfare of the Institute as a whole.

Jan 1, 1938

THREE-QUARTERS of the amount needed to defray the cost of the Louvain memorial clock and carillon has been subscribed by one-thirtieth of the total number of mem- bers of the engineering societies that are indorsing this memorial to the engineers who gave their lives in the Great War. Gifts of materials and services have been made, but about $20,000 is still needed to meet the total expense involved. Small contributions from the twenty-nine-thir- tieths of the total membership who have not yet subscribed should promptly provide this sum. The accompanying illus-tration shows the 48 gold stars made by the American Brass Co. for the four faces of the clock, being boxed for shipment at the works of the Dwight & Lloyd Co. at Netcong, N. J. The actual material of the stars is, of course, an aluminum bronze, which retains its gold color without tarnishing.

Jan 5, 1928

By Ellsworth Daggett

The Berlin gold-quartz mine is situated in Nye county, Nevada, on the west flank of the Shoshone range, about 40 miles south and 30 miles west from the town of Austin, the county-seat of Lander county. The distance from Austin is about 60 miles by stage-road. The outcrop of the vein, at the top of the incline-shaft, is situated just at the base of the mountain proper, almost exactly at the intersection of the mountain-side with the gravelly bench that slopes for about three-quarters of a mile to the flatter sage-brush plain, or desert valley, below. The vein itself consists almost entirely of quartz, with perhaps 2 per cent. of sulphide of iron, copper, lead, zinc and antimony, and perhaps a trace of some of the compounds of tellurium with gold and silver, although none of the latter have been as yet positively identified. The relative proportion, by weight, of silver and gold in the ores, varies in different parts of the vein, from 12 silver for 1 of gold, to 7 silver for 1 of gold. The quartz vein-filling is usually frozen fast to the walls, and is very hard and compact, seldom showing the friable, fissured, or shelly structure often to be found in quartz-veins. Comparatively little evidence of relative motion of one wall of the vein upon the other is to be found—a fact indicating that during the formation of the vein, and prior to the extensive movements herein described, little disturbance had taken place. No evidence whatever of metasomatic origin has been observed. On the other hand, occasional occurrences of comby structure, in which the axes of the quartz-crystals are at right angles to the plane of the vein, rather indicate deposition from solution in a pre-existing fissure. Spurs, or branches, and small parallel veins, while not en-

Jan 1, 1908

By James A. Lewis

It is the purpose of this paper to show the importance of sand characteristics, when combined with other physical data, in evaluating production obtained by secondary recovery operations, and to indicate the benefits to be gained from the application of these principles to primary production.

Jan 1, 1942

By Eugene Guccione

"All engineering societies should encourage and motivate their members to take part in public affairs. And engineers, in turn, should learn to translate their technical knowledge in a language which politicians can understand," stated James Boyd last month as he received the Hoover Medal, which is awarded annually by four engineering societies-AIME, IEEE, ASME, and ASCE-to an engineer who has rendered important public service. James Boyd is no ordinary engineer (see box). A few weeks ago, Dr. Boyd took time out of his busy schedule to stop at MINING ENGINEERING'S editorial office for the following exclusive interview.

Jan 1, 1976

By Thomas O. Breitling

The Mill Design Session at the Annual Meeting in New York next February will have a total of four papers. All of these papers will be concerned with the subject of in-plant dust in the hard-rock mining industry. The emphasis on efficient dust collection is timely, because dust is a problem not yet adequately covered in AIME papers. In general, dust collection should be the step following dust suppression. Dust collection and its return to the ore recovery circuit, or its waste to tailing are sources of added operating cost. If possible, dust should be kept in the main stream of ore flow by suppression.

Jan 1, 1970

By Carl Zapffe

The manganese ore reserves of Lake Superior, because of their location and nature, have recently achieved a rnarked degree of importance as compared with the world's manganese reserves. To appreciate fully the significance and the adequacy of this reserve, one should understand how such ores are used, where obtainable, the quantity used, possible avenues for increasing use or application, and the chemical and physical characteristics of the available ores. Only with those data at hand, is it possible to arrive at a convincing answer to the question whether the reserves of manganiferous iron ores are adequate to satisfy the annual demand of the presently known iron ores for the full life of the latter. That they should last is vital; and to ascertain whether they will last was the purpose of the present investigation, which marks the first attempt to study these Lake Superior reserves. The Lake Superior region possesses and supplies the full assortment of iron ores needed for the conversion of ore into pig iron and steel ingots and castings. These ores are named bessemer, low-phosphorus and high-phosphorus non-bessemer, manganiferous and siliceous; and to include the term aluminiferous would be in keeping with the most recent nomenclature adopted by some dealers. About 35 or 40 years ago, perhaps less, most of the Lake Superior ore which is being used today was the material then considered either useless or too poor for immediate use; perhaps it was considered no more than a future reserve. An examination of the analyses of ores and the guarantees in the sales of those older times convince one that the opinions of those days must have been governed by only small differences in analyses. Some grades of ores used today in substantial amounts were used most sparingly only one or two decades ago. The relative quantities of the different ores used are ever changing; and, bit by bit, the metallurgy and the opinions are ever changing and the prejudices against certain ores and practices decrease. This is unquestionably more pronounced for the manganiferous ores than for any other kind. If, when using the present data for manganiferous ores, we will only be content to make allowances for the same experiences other kinds of ores

Jan 1, 1927

By Bernard Lallement

INTRODUCTION Geostatistics have been used for five years at the B. R. G. M. to compute the ore reserve estimation. At present this technic is also used at the beginning of the exploration project to determine the best way to prove the orebody. The best way is a compromise between the cost of the exploration and the precision of the estimation. It is clear that geostatistics cannot be used without any data, but very often an exploration project is decided on an orebody which has already been drilled. Old data can therefore be used. This was the case this year for two orebodies: an iron deposit and a lead deposit. The iron deposit was explored by drifts and has now to be proved. We used geostatistics to determine the best drilling pattern. The variograms computed with these old data showed that an anisotropy existed between the two directions of the orebody, which meant that the drill pattern had to be rectangular. The lead deposit was explored by drill holes and a short drift in part of the orebcdy. The problem was to choose between a regular pattern of drill holes or a long drift and some added drill holes. The case of this study will be exposed afterwards. On the other hand, if the orebody is completely unknown, the exploration project generally forecasts two exploration steps (the first step

Jan 1, 1977

By Stirling Huntley, R. H. Johnson

Pennsylvania will be remembered, as long as oil is produced, as the cradle of the industry of petroleum in North America. It was on Oil Creek, near Titusville, Venango Co., that Col. Edwin L. Drake, superintendent for the Seneca Oil Co., brought in the first commercial oil well on Aug. 28, 1859. Great difficulty was experienced in getting the well down to the producing depth of 69 ft. (21 m.) with the spring-pole system then in vogue for punching shallow water wells, so the novel expedient of driving an iron tube through the surface clays and quicksand was finally resorted to. The well had an initial yield of 25 bbl. a day on the pump, but soon went off, though 2000 bbl. were produced by the end of the year. With the Drake well a success, a young industry sprang into being, the rapid growth of which has been second to none in the country and the value of whose product is only surpassed by that of coal. For years the only producing territory, the Pennsylvania-New York field attained its greatest production in 1891, when the bringing in of the McDonald pool, between Pittsburgh and the West Virginia line, gave a total of over 33,000,000 bbl. At present the field, combined with West Virginia and southeast Ohio, gives 25,000,000 barrels. Geology and Stratigraphy In general, the Appalachian field is a huge geosyncline, the axis of which runs roughly northeast-seuthwest, from north of the New York state line south through Brookeville, Kittanning, Pittsburgh, Washington, through the southwest corner of the state of Pennsylvania into West Virginia. Minor folding has accompanied or followed the dominant fold of the field, and it is from these structures near the Pennsylvania-West Virginia line and their influence on the accumulation of oil and gas that I. C. White, state geologist of West Virginia, obtained his evidence for anticlinal guidance of prospecting. Many horizons in the geologic column of the field serve as reservoirs, and there arc several pools that have wells producing side by side from different and widely vertically separated strata. The strata show a promising succession of porous sand and conglomerate horizons alternating with numerous gray and dark brown 01. black shales, admittedly

Jan 1, 1921

Gerald Sherman, Bisbee, Ariz. (written discussion*) .—The fact that, after a change in the hours of labor, as much work is found to be done in 8 hr. as was accomplished in 10, probably results from the more rigid examination of operating methods that is made when the management faces new and more difficult conditions. Although A better working pace will prevail, most of the gain will result from economies of plan and only a part of it from the improved effciency of labor. The Iabor of shoveling is so severe that it may be easily believed that a working period of less than 7 hr. will give maximum results, but there arc many other occupations about a mine in which this is not true, and in which the rate of accomplishment is in proportion to the time employed, up to 9 or 10 hours. Mr. Harley's study of shoveling has becn thorough, and demonstrates the benefit of investigation and education even in such simple work, but his reference to methods of payment opens a subject even more important in mine management. The efficiency of labor may be excellent, but unless a method of equitable payment accompanies it, the result will be only temporary. With strict but sympathetic supervision, a good average day's work can be obtained; but with the exception of those unusual men who cannot be restrained from working to their limit, an average daily wage does not bring out the remarkable performance of which many men are capable. There is also a considerable variation in the average amount accomplished, dependent on the supply of Iabor. This can readily be shown by any labor record that covers several periods of shortage or superabundance of labor. An increase in the daily wage in the time of labor shortage does not necessarily bring out an increased day's work; there is usuaIly a decrease in labor efficiency at such times regardless of the wage, whenever a daily rate is used. Rewards to individuals for exceptional performance appearing as an increased rate of pay cannot be made in a large organization without bad feeling. In a small organization, an individual's ability may be so well recognized that different rates of pay can be applied. Exceptional work can only be obtained by a method of payment based on the valuable results accomplished. As a basis for such payment, an

Jan 1, 1920

By W. R. Ingalls

THE present administration has made sincere and effective efforts to reduce the expense of the Federal Government, but it has reached a point beyond which it seems impossible, or anyway extraordi-narily difficult, to go. This is ascribable to the large part of the budget that is represented as war expense. There is no doubt that this spells high taxation for many years to come. Nevertheless, although a large part of the taxation will be attributable to the war, the paying out of the proceeds of that taxation by the government will not be war expense, except in minor part, as will be hereinafter made clear. It will be useful to explain the economic meaning of this situation, for it has bear-ings upon several open questions, such as a bonus to the ex-soldiers, the foreign debt accounts, etc. The expense of the war on the part of the American people was in the main paid concurrently with its prose-cution. This was necessary. Warfare is not conducted with money, but with materials and labor. Except for such previous production as was represented by stocks of goods, the requirements had to be supplied by coincident production. With the end of 1918 our war expense ceased, save for such production, e.g., of ships, that was allowed to run on unchecked, and the indemnities that had to be paid for cancelled contracts. When those matters have been settled we shall be done, barring one important thing. Of course, our war expense began to contract right after the armistice and shrunk rapidly with the demobilization of the troops in 1919. If we had not been able to obtain all needful material from our own sources and had been constrained to borrow it from foreign countries, incurring a foreign debt, we should have been in the quite different posi-tion of having to repay that material, or its equivalent, during subsequent years. The European countries had to come to us for such supplies. This outlines the fundamental difference between their present situations and ours. We were therefore compelled not only to furnish materials and man-power for our own warfare but also much for the Allies.

Jan 3, 1923

By N. Albon, J. F. Miller, R. W. Coutant

The deposition of nickel from nickel carbonyl onto amorphous substrates has been studied, with attention being paid to the specific effects of the physical and chemical nature of the substrate and to the effect of oxygen on the crystal morphology. With substrates having microscratches or etch lines, nu-cleation was observed to occur preferentially at these surface features. Flame polishing of the substrate surfaces was found to remove any regularity in preferred nucleation sites. Nucleation was observed to occur less readily on substrates having relatively low surface energies, e.g., Teflon and carbon, than on materials having relatively high surface energies such as fused silica. At low oxygen concentrations [Ni(CO)4/O2 > 54 x 1031, apparently pure and well-formed nickel crystals were observed to nucleate and grow irrespective of the presence of oxygen. At higher concentrations of oxygen, a secondary growth process, dependent upon oxygen concentration and resulting in a gradual change in crystal morphology, was observed. It is concluded that the influence of oxygen on the nucleation and growth of nickel is determined by the relative kinetics of the various possible reactions, and that under the experimental conditions employed the 0-Ni interaction occurs at some nucleation or prenuclea-tion stage. THE purpose of the research on crystal nucleation in chemical vapor deposition as described in this paper has been twofold: 1) to examine some effects arising from the use of amorphous substrates, and 2) to study the specific effects of oxygen on the nucleation and growth of nickel in a nickel carbonyl-carbon monoxide system. The nickel-nickel carbonyl system was chosen for study for several reasons: 1) nickel films are of potential interest in electronic technology, and 2) the deposition can be carried out at moderate temperatures, thus making possible detailed study of the processes occurring and the use of a variety of substrate materials (including some which melt at relatively low temperatures). Fairly well-characterized chemical kinetics and a broad background of information are available on the py-rolysis reactions and on the mechanisms of Ni-O interactions. NUCLEATION AND GROWTH THEORY The theoretical background for the analysis of nucleation and growth by vapor deposition for a one-component system (physical vapor deposition) and the problems encountered therein have been reviewed by Hirth and pound.' More recently Mande12 has indicated the difficulties of applying such theory to chemical systems. One of the major problems involved is the possible multiplicity of chemical reactions and deposition routes. For example, those reactions which are probably of significance in a discussion of the pyrolytic deposition of nickel from nickel carbonyl under the conditions of the present experimental work are illustrated in Fig. 1. As is true with most cases of chemical deposition, many of the quantitative data necessary for a complete analysis of the system are either not available or not directly measurable. However, with the present system, sufficient data are available for a discussion of nucleation and growth on a qualitative basis. Classically, the rate of nucleation of a monatomic species being deposited from a vapor phase is given by

Jan 1, 1965

By R. C. Rumble

To /neet the need for a subsurface flowmeter capable of measuring low rates of flow, a new type flowmeter has been built and tested in the field. This instrument is self-contairzed, can be run on a wire measuritzg line, and may be run through 2-in tubing. It consists of a rotameter flow-measuring assembly used in conjuncfion with a conventional subsurface instrument clock and chart. Integral with the tool is an inflatable packer which, by effecting a seal between casing and tool, diverts all fluid through the metering assembly. Packers of different size adapt the tool to different sizes of casing or liner. The flowmeter is capable of measuring rates of flow as low as 4 BID. The flowmeter has been run experimentally in seven wells. It has yielded satisfactory resrrlts in five of the wells, and in the other two it failed to operate because of loose sand in the hole. INTRODUCTION One of the oldest problems facing the producing branch of the petroleum industry is the location of depths of entry of fluid into a wellbore and the determination of the amount of fluid entering at each depth. This problem is often encountered in oil and gas wells completed in single producing horizons as well as in multiple pays; it is a common problem in oil wells which produce excessive volumes of gas. Several subsurface instruments designed to detect and meter flow in the producing interval of wells have been described in the literature.1,2,3,4 Most of these, however, were apparently intended for use in wells producing at relatively high rates of flow, and consequently lack sensitivity to low flow rates. Because of this and of other possible disadvantages inherent in these instruments, development of the subsurface flowmeter described in this report was undertaken. DESIGN OF FLOWME'I'ER Design Requirements In considering the requirements for a flowmeter that would not be subject to the limitations of devices existing at the time work was started, attention was first given to the size of the tool. Such an instrument should be of sufficiently small diameter that it could be lowered readily in 2-in tubing in a producing well. The flowmeter should contain a recording unit so that it might be run on a wire measuring line with conventional reeling equipment. It should not be too long to be accommodated by a portable lubricator of the type used for running conventional subsurface instruments. The metering mechanism of the flowmeter should not be affected appreciably by the viscosity or density of the flowing fluid. Such an instrument should record flow rates in the range from less than 10 B/D to over 100 B/D. To achieve this, a packer should he provided to divert through the instrument all fluid flow in the wellbore. This packer should be of such nature that in the event of excessive flow the fluid would bypass the instrument instead of forcing it up the wellhore. General Description A flowmeter incorporating most of the desired features outlined above was developed and built. The instrument is an elongated tubular device terminated on

Jan 1, 1956

By H. D. Kynor

By the term mechanical mining is meant that operation, or series of operations, that replace the hand methods of mining. The first undercutting machine to operate in anthracite was placed in the Butler mine of the Hillside Coal and Iron Co., Dec. 23, 1910, by the Sullivan Machinery Co. The first Jackhamer used in the anthracite field was installed at the Wadesville colliery of the Philadelphia & Reading Coal and Iron Co. in Oct., 1912, by the Ingersoll-Rand Co. The first longwall conveyor was installed at the Dodge mines of the Delaware, Lackawanna, & Western Coal Co. in March, 1912. The first mechanical scraper equipment was installed in the Seneca mines of the Lehigh Valley Coal Co. in January, 1914. The amount of anthracite mechanically mined since the first mining machine was installed in 1910" is as follows: Penna. Coal Co. D. L. & W.. ScRanton Temple Hudson YeaR and Hill- Tons Coal Co., Coal Co., Coal Co., Total, side Coal Tons Tons Tons Tons and Iron. Tons 1920................ 372,737b 367,000d 322,892 74,127 371,878 1,508,634 1919................ 950,786 no record 306,616 81,575 319,356 1,658,333 1918................ 917,778 744,966 24,880 44,756 288,781 2,021,161 1917................ 757,940 838,800 5,050 57,279 164,180 1,823,249 1916................ 286,780 860,663 13,960 114,173 101,475 1,377,051 1915................ 428,819 592,169 8,253 1,029,241 1914................ 219,188 153,896 373,084 1913................ 171,505 1912................ 124,267 124,267 1911................ 40,319 40,319 1910................ 1,184 1,184 a A slightly greater production was obtained than here indicated, as the tonnage from individual operations is not shown. b Decrease due to strike conditions in 1920. c Does not include tonnage of D., L., & W. d D., L., & W. decrease in 1920 due to having fewer mining machines in operation. There are about 150 undercutters in use in the anthracite region, 80 mechanical loaders, and 10 longwall conveyors.

Jan 1, 1922

By G. R. Love

i\ program has been written which allows fully automatic conversion of data for X-ray intensity, as a function of time, to finished conventional pole figures. The program accepts input data in the serial order in which they are taken and is therefore immediately compatible with automatic data-acquisition devices. From these data taped instructions are prepared for the Calcomp plotter to construct ink-on-paper drawings. Because both Siemens and Norelco pole figure goniometers are used in this laboratory, the program was written for pole figure data obtained from one or more interpenetrating spiral scans during which both the polar angle, @, and the equatorial angle, a, are varied simultaneously and continuously. The reference direction for a scan, that is the point @ = 0 deg, may be chosen coincident with either the normal direction (N.D. figures) or the rolling direction (R.D. figures). In either case the plotted figures are drawn with the transverse direction (a = 0 deg) at the right and the rolling direction at the top. The full, circular, pole figure is drawn as two semicircular figures labeled "front side" and "back side". As presently constituted, the program will also accept data from circular scans taken at constant values of @. In every case the angular coordinates of each intensity entry are generated in the computer from a relatively small number of auxiliary data. The X-ray intensity data are corrected for background scattering by direct subtraction of the intensity measured with 28 set appropriately "off" the Bragg angle. It is possible to enter this correction as an additional spiral scan through the a, @ space; because the background correction does not normally vary rapidly enough to warrant this detailed a determination, the background corrections are entered as one or more auxiliary data. All data are normalized to a multiple of random intensity. The data taken in this laboratory for N.D. figures are normally taken in a reflection geometry from from sheet samples and do not extend beyond <p = 75 deg; for these data random intensity must be determined from separate experiments and entered as auxiliary information. When the auxiliary information is not available, a number is chosen to give intensity values normalized to a scale of 1 to 10. In this laboratory, R.D. figures are based upon hemispherical samples for which data are taken out to @ = 90 deg; for these data random intensity is calculated by direct numerical integration of . sin @ d@ using the trapezoidal rule and the background-corrected values of the input data. Points necessary to the construction of the pole figure are identified by simple linear interpolation between adjacent data points to determine the loci of contour lines. Points lying on a given contour are connected to one another with straight-line segments and the search-calculation-drawing sequence is patterned to assure that different contour lines do not cross, that a single line does not branch, and that lines do not end in space. However, so that there be no ambiguity in the data presentation, all contour lines end at the limits of the input data. Since the curves are constructed of straight-line segments, they are not continuous in their derivatives. However,

Jan 1, 1969

By F. J. Dunkerlery, V. Damiano, J. Fulton, F. Pledger

Grain-growth and recrystallization characteristics of a commercially pure zirconium prepared by the iodide process are reported. Grain growth from 640° to 800°C was continuous once initiated and obeyed D = kt". Recrystallization of zirconium occurred at temperatures of 450° to 550°C after deformations of 20 and 50 pct. Hardening from partially soluble inclusions prevented determination of the absolute rates of recrystallization, but the relative rates of recrystallization obtained are useful as a guide in fabrication practice. BASIC information needed as a guide in the hot and cold working and annealing of metals includes recrystallization and grain-growth data. A search of the literature revealed no such information for pure zirconium. This is a report of practical grain-growth and recrystallization results obtained for a commercial grade of pure zirconium on a project sponsored by the Office of Naval Research. In this work, isothermal grain-growth curves were obtained at five temperatures from 640" to 800°C inclusively; while recrystallization curves have been determined at 450°, 500°, and 550°C for the metal at the deformation levels of 20 and 50 pct. In addition to the usual variables of temperature, time, and deformation, distribution of the second phase found in all commercial grades of iodide zirconium is also treated as an important factor in these grain-growth and recrystallization studies. In conducting this work, two properties of zirconium were particularly pertinent in dictating experimental conditions. First, since zirconium undergoes a transformation from the a close-packed hexagonal form to the ß body-centered cubic form at 862°C, no recrystallization or grain-growth studies were made above 800°C. Second, because dissolved gases (oxygen, nitrogen and/or hydrogen) increase the hardness and lower the ductility of the solid metal, all annealing treatments in this investigation were carried out in vacuum or in a helium atmosphere. Materials and Methods The zirconium used in this investigation was prepared by the Foote Mineral Co. by deposition from its iodide. A spectrochemical analysis of the metal showed the following composition in weight pct: Hf, 2.1; Mg, 0.012; Fe, 0.035; Si, 0.095; Ti, 0.023; Al, 0.037; Mo, trace; Ni, trace; Cr, trace; Ca, 0.006. Conventional metallographic procedures involving hand polishing on wet metallographic papers, followed by final polishing on fine, levigated alumina on gamal cloth and a medium speed wheel were used throughout this investigation. Grain boundaries were revealed with modified Tucker&apos;s etch containing 20 parts glycerine, 2 parts hydrofluoric acid, and one part nitric acid. Grain-Growth Procedure: Three lots of zirconium, designated here as series A, B, and C were prepared for the grain-growth studies as follows: Series A was prepared by cold swaging the % in. as-deposited rod to a 3/16 in. final diameter, followed

Jan 1, 1952