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Jan 1, 1963

By H. F. Silliman, Daniel R. Hull, Earl W. Palmer

THE brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that [ ] contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6 ¾ in. wide by 1 in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. [ ] In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breaking rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause-however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By Frederick Görannsen

McDuffie county, once a part of Columbia county, lies in the eastern part of central Georgia, about 20 miles west of the Savannah river, and bounded on the northtwest by Little river. Wrightsboro, now almost forgotten, was one of the principal towns of Georgia before the Revolutionary war, and much of the land hereafter described as belonging to one of the principal gold-bearing sections of the South had been taken up by the early agricultural settlers, and was already under cultivation. Indeed, some of the present mining companies can trace their chain of title back to the original grant of King George III., made in 1771. The first discovery of gold in Georgia, however, was not made until 1823, when two English miners, who had emigrated to this country and were traveling as peddlers through this section, discovered quartz, rich in gold, on what is now known as " the 40-acre lot," and owned by the Columbia Mining Go. These men had no money to buy the lands, and not being able to stake off a claim and begin work, as is the custom in other places, they were forced to seek the aid of the native farmers. In this we are told that they were for a long time unsuccessful; the farmers and land-owners not knowing or caring anything about gold mining. In 1826, Jeremiah Griffin, a wealthy farmer, became interested with them, and they did some prospecting and located several rich veins. Mr. Griffin soon became enthusiastic, and bought about three thousand acres of supposed gold-lands, lying along Little river.. This purchase was unfortunate for the mining industry, as it effectually shut out all other prospectors, and confined entirely to Mr. Griffin and his associates the mining development of the whole region. As a consequence, the ground was never covered, arid there are virgin lands in this section now, which offer to the prospector as

Jan 1, 1903

Edward K. Landis, Philadelphia, Pa.: In studying Mr. Thackray's paper it seemed that a critical comparison of the results from different methods therein reported would he of interest. For this purpose Table I. was constructed by grouping all determinations made by the same method, and the probable errors were calculated. In this table all chemists titrating with permanganate (A1, E, F, G and 0 of Mr. Thackray's paper) are classed under "Emmerton;" those titrating with nitric acid (C, J, S and Y) under " Handy; " those re Probable error of result: a, ±0.0008996; b, ±0.000694; c, ±0.00107; d, ±0.00115; e, ±0.000674; f, ±0.000473; g, ±0.003675; h, ±20.0007959; i,0.000.5098; k, ±0.0008303. Probable error of single determination: a, ±0.001989; b, ±0.001547; c, ±0.00214; d, ±0.0023;e, ±0.00116;f, ±0.000818;g, ±0.0019;h, ±0.00224; i, 40.00143; k, ±0.00234. The formula for calculating the probable error is 0.6745, where N (N— 1)' S is the sum of the squares of the differences from the mean and N is the number of determinations.

Jan 1, 1897

By W. L. Remick

The hydrotator coal-cleaning process was developed as an economic necessity to meet the ever-increasing demand for an inexpensive method of cleaning coal down to the sizes ordinarily referred to as "dust." As the most urgent demand seemed to be in the anthracite field, all experimental work has been conducted in that territory during the past two years, with the exception of a few months during the strike of 1925-26, when some experiments were performed in the Alabama bituminous fields. The first commercial plant was constructed at the Middle Creek Colliery of the Philadelphia & Reading Coal & Iron Co.,. Pottsville, Pa. This plant is now operating. Application The field of application of the process is: 1. Cleaning anthracite fines, ordinarily described as "slush" or "silt." Slush contains all sizes from 3/32 in. down to and including I(dust." (Anthracite passing a 3/32-in. mesh is also referred to as No. 2 Barley and No. 4 Buckwheat.) 2. Cleaning sizes too fine for recovery by other methods. 3. Removal of coal from sand circulated in the Chance sand-flotation process. 4. Cleaning of bituminous sizes from % in. down to "dust." 5. As equipment for the performance of the froth flotation process. 6. Other separating, extraction and washing processes which may be considered outside the realm of coal cleaning. Principle of Operation Fig. 1 shows the method of classification practiced under the Hydrotator patent.' In coal cleaning the machines are operated as "hindered settling" classifiers, the flow of solids and liquids being so controlled that the units may be combined in series.

Jan 1, 1927

By C. Feng, W. E. Krul

A study was made of the development of texture and the anisotropy in plastic flow of Ti-8Al-1Mo-1V alloy. Based on Pole figure determinations, the shifting of texture induced by rolling at approximately 400°C was found to be due primarily to slip rotation for the major Portion of the material. Grain boundary shear is believed to be an important factor. The anisotropy of the textured alloy was examined in terms of the variations of yield stress under tension and the ratio of bi -axial strain increments µp, in the temperature range 25" to 290°C. The results were related to Hill&apos;s theory on plastic anisotropy. The Schmid factors of (1100)[1120], (1101)[1120/, and (1101)[1120] slip systems were analyzed and found to be compatible with the observed anisotropy. Cross-slip between these planes was proposed as a possible deformation mode. In a number of published articles, considerable interest has been directed to the possible achievement of texture hardening in hcp metals. Following Backofen, Hosford, and Burke,&apos; this phenomenon was related to the yield criteria of the material and was expressed in terms of the biaxial strain ratio, r = d?w/d?l. The higher the value of r, the greater is the expected potential for texture hardening under certain loading conditions. For a given material, r varies with direction. Such variation can be traced to the anisotropy in plastic flow and can be explained within the framework of the various modes of deformation. Hatch2 found that a high r value coincides with a texture whereby the (0001) pole is closely aligned with the surface normal for sheet materials, Based on the analysis of the slip on the {1010}, {1011}, and (0001) planes, Lee and Backofen3 and Avery, Hosford, and Backofen4 concluded that the resistance to thinning is reduced by the operation of the (0001) <1120> slip system; with this reasoning they were able to explain the low r values (i.e., r « 1) observed in magnesium alloy sheets in the rolling direction and in commercially pure titanium in the transverse direction. The general equation, dealing with plastic flow in a polycrystalline aggregate has been used to correlate the plastic anisotropy and texture. In this expression, T and s are shear and normal stresses, and dri and d? are shear and normal strain increments, respectively. Assuming that five slip systems are operative within each grain and applying the principle of maximum work,5,6 one can determine the m value among the available systems. On this basis, Hosford7 and Chin, Nesbitt, and Williams&apos; were able to correlate m with yield stress under plane-strain compression, and Svensson9 was able to predict the variation of yield stress in textured aluminum. These workers made their analyses from materials in which slip operation is known to be associated with plastic flow. Questions remain regarding the derivation of Hill&apos;s theory on plastic anisotropy,10,11 since it was formulated on von Mises&apos; yield criterion.&apos;&apos; Its ability to deal with other forms of deformation has been in doubt.13 Others have discussed the validity of Hill&apos;s quadratic equation relating strain and yield stress.14&apos;15 For hcp titanium, deformation by various modes of slip and twinning operations has been reported.16-20 If all possible modes of deformation operate and contribute substantially to the plastic flow, it is difficult to imagine how the quadratic expression can suitably describe the anisotropic plastic flow of titanium alloys. Backofen and Hosford15 considered that Hill&apos;s is a macroscopic theory and implied that the major mode of deformation by slip mechanism will adequately describe anisotropy of the material. In the present investigation, slip operation will be shown to play the major role in the development of sheet texture induced by rolling of a commercial titanium alloy. Although twinning and other modes of deformation may also operate, their operation is believed to be secondary. The anisotropic properties of the sheet, which can be expressed in terms of directional variation of r, µp = -d?w/d?l and the yield stress will be shown to be governed primarily by slip operation. MATERIALS AND EXPERIMENTAL TECHNIQUES The titanium alloy chosen for the present investigation had a nominal composition of 8 wt pct Al, 1 wt pct Mo, 1 wt pct V, and 0.1 wt pct interstitial impurities. Sheets varying between 0.1 and 0.15 in. thickness were used. The alloy was received in a condition which was prepared by rolling at 900°C and annealing at 700°C. Subsequently, the sheets were subjected to further reduction in thickness by rolling at 400°C. A total reduction in thickness of 65 to 70 pct was obtained by a series of quick passes in a rolling mill with intermediate reheating. Further reduction in thickness was not possible due to cracking developed at the edges of the sheets. X-ray measurements were conducted in a Siemens and a Norelco unit to determine the texture of the sheets. Reflection techniques were used exclusively with CuK, radiation and a nickel filter. The loss of X-ray intensity due to geometric defocusing was calibrated with a technique described previously." The (0001), (1010), and (1071) pole figures were plotted from 0 to 80 deg, and to present the texture elements quantitatively, inverse pole figures were constructed following the technique described by Jetter, McHargue, and Williams.22 Tensile experiments were carried out at 25", 175",

Jan 1, 1970

By Nicholas J. Grant, Robert H. Kane, Bill C. Geissen

The platinum-rich section of the Ta-Pt Phase diagram was worked out by metallographic and X-ray techniques, using twenty alloys; solidus temperatures and solid solubilities were determined. Besides s phase, four intermediate stoi-chiometric phases were found: TaPt (high-temperatzrre phase, structure unknown); TaPt2 (ortho-rhomhic, new type); a TaPt3 (orthorhombic, TiCu3 type); ß TaPf3 (monoclinic, new type). TaPt2 and TaPt3 melt congmentlv; two eutectic, two beritec-tic, and one eutectoid reactions occur in the inuestigated range. THE Ta-Pt system was examined as part of a study of the phase diagrams and the intermediate phases of niobium and tantalum with Group VIII transition metals. Since the main scope of this work was the relation among the ordered close-packed phases occurring in the concentration range from AB to AB3 (A = Nb, Ta; B = Pd, Pt, and so forth), only the platinum-rich side of the diagram was worked out thoroughly, while spot checks were made to determine the approximate outline of the tantalum-rich portion. The system has not been thoroughly treated in the literature; Greenfield and Beck1 in their survey of refractory metal intermediate phases found a o phase between -18 and 37 at. pct Pt which coexists at higher platinum concentrations with an unidentified intermediate phase. Browning2 worked on the range between 55 and 100 at. pct Pt; however, this preliminary study did not cover temperatures >1500°C, and included no conclusive crystallo-graphic data. More recently, a study of the platinum-rich section of the Ta-Pt system has been carried out by Ray,3 while Hartley, Parsons, and steedly4 have studied the tantalum-rich section. The crystal structures of TaPt2, a TaPt3, ß TaPt3, and others have been reported in abstracted form by Giessen and Grant.5 EXPERIMENTAL METHODS The methods of alloy preparation and processing and of the metallographic and X-ray procedures follow very closely those described by Ritter, Giessen, and rant&apos; for other refractory metal-noble metal systems, and will not be repeated except where significant differences exist. Starting materials were: tantalum rod of 99.95 pct purity, supplied by National Research Corp., and platinum sponge 99.9 pct, supplied by The International Nickel Co. An oxygen analysis of the tantalum rod showed 30 ppm O; other impurities were C, N, Si, Nb, Mo, none of these exceeding 50 ppm, and 100 ppm W. Homogeneous buttons were readily prepared as follows: ingots of 5 g were weighed and arc-melted under welding grade argon, followed by two remelts after inverting the button. Between 40 and 100 at. pct Pt, weight losses during the first melt rarely exceeded 0.1 pct, in which case the alloy was rejected, and were nil on subsequent remelts. Since the vapor pressure of platinum far exceeds that of tantalum, the small evaporation loss could be assumed to consist of platinum; therefore, a corresponding amount of platinum was added on the second melt. Since it was confirmed on pure tantalum samples that no weight gain through oxygen or impurity pickup occurs (see Ref. 71, it could be assumed that the uncertainty in the composition did not exceed ±0.1 at. pct for the range 40 to 100 at. pct Pt. For the four control melts from 0 to 40 at. pct Pt, an error of ±0.5 at. pct was calculated. Microscopic examination of the whole buttons after melting showed no inhomogeneity other than local coring. This was eliminated by a homogenization heat treatment. A total of twenty-three alloys were prepared. Heat treatments were carried out in a tantalum

Jan 1, 1965

By A. N. Holden, W. E. Seymour

DURING the last several years, the U-Zr system has been studied at many laboratories as one of the research programs sponsored by the Atomic Energy Commission. The equilibria in part of this system have been difficult to determine, although the phase diagram from 0 to 60 atomic pct Zr has been established with reasonable certainty. Existing diagrams of the system vary appreciably beyond 60 atomic pct Zr, particularly with regard to the existence of an intermediate phase. Most existing diagrams show a transformation or reaction horizontal near 600°C. In 1955, a collection of uranium phase diagrams&apos; was prepared at the Battelle Memorial Institute and the U-Zr diagram in that collection contained a questionable region in the vicinity of 60 to 80 atomic pct Zr. Summer-Smith" has published a phase diagram of the system that shows no intermediate phase. Summer-Smith did his work with powders and found only the uranium and zirconium eutectoid mixture from X-ray patterns of material annealed below 600°C. Mueller3 at Argonne National Laboratory did similar work with filings, and he found that initially there was a pattern of an intermediate phase, but on long-time annealing

Jan 1, 1957

By J. S. Diller

In 1827, chromite was discovered near Baltimore by Isaac. Tyson, Jr., who initiated the mining of chrome ore and later (1845) the manufacture of chromium compounds in this country. From 1828 to about 1560 the United States, supplanting Russia, supplied chromite for most of the world. Chrome deposits were found also in California, and the Tyson Company shipped ore to Philadelphia by way of Cape Horn. In 1848, J. Lawrence Smith, an American in the employ of the Porte, discovered large bodies of chromite in Asia Minor. They were developed in 1865 and became the chief source of the world&apos;s supply for a number of gears. The discovery of the large high-grade bodies in New Caledonia., and later in Rhodesia, with other foreign sources, gives at present an abundant supply for all demands. For a number of years before the great war. the United States produced only a few hundred tons of chromite annually, for local use, but during the war the demand for domestic ore resulted in a production of more than 82,000 long tons of crude ore in 1918, and it was demonstrated that the United States has reserve deposits equal to a war demand of several years&apos; duration. Now that the war is over, the country is con-serving its domestic supplies by employing higher-grade but cheaper ore from foreign countries.

Jan 9, 1919

By I. Cadoff, E. Miller, K. Komarek

Jan 1, 1960

By E. P. Abrahamson II

The effect of transition elements which form binary solid solution upon the recrystallization temperature of zirconium has been investigated. All additions raised the recrystallization temperature. A correlation is obtained between the logarithm of the rate of change of recrystallization temperature with atomic percent solute and the free atom ground state electron configuration of the solute element. ThE work of Abrahamson, et al., on dilute binary solid-solution alloys indicated a correlation between the free-atom ground state electron configuration of the solute and either the brittle-ductile transition or recrystallization temperature. These studies were carried out on bcc base materials. The implication is that the outer s and d electrons of the solute are the prime determinant of the absolute rate of change of recrystallization or transition temperature. Furthermore, the limit of linearity has been shown to be a function of solute electron configuration for recrystallization in iron and vanadium. To date no Complete systematic recrystallization study of dilute binary zirconium base alloys has been made. It is the purpose of this study to note whether the change in solvent structure from bcc to hcp will influence the correlation. It was also desired to learn more of the role of the electron configuration of the solvent on recrystallization temperature. PROCEDURE All alloys were made using 99.87 pct Zr with 0.01 Cr, 0.04 Fe, 0.006 Hf, 0.003 Mg, 0.003 Mn, 0.003 N, and 0.080 0 (132 BHN). The solute elements were 99.9 pct pure. According to the published binary phase diagrams6 and metallographic examinations at X750, all alloys used were solid solutions. The alloys were arc melted and remelted six times in the form of cubic 200-g buttons under an argon atmosphere. They were then hot pressed at 950°C to 0.450 in., upset pressed to 0.350 in., and annealed at 800°C for 1 hr. The specimens were then Blanchard ground to 0.250 in., removing 0.050 in. from each side. The grain size of the material at this stage was found to be 8000 100 grains per sq mm. The specimens were then cold rolled to 0.130 in. and cold pressed to 0.125 in., yielding 50 1 pct cold work. All alloys were then chemically analyzed for the principal addition. The interstitial contents remained at the values of the starting material when checked on random alloy specimens. The rolled sheet was cut into 6.75 by 0.25-in. lengths and heat treated in a gradient furnace for 1 hr. The gradient was 250o to 900°C over the 6-in. length, recorded continuously by six thermocouples resting on each specimen. Control was 3oC, accomplished at the hot end. The recrystallization temperature was determined metallographically using polarized light. The criterion chosen was the point on the specimen showing the first recrystallized grain at a constant magnification, X200. Specimens were repeated, and the agreement was found to be 3°C. RESULTS Three different pure zirconium specimens were tested, and the recrystallization temperature was

Jan 1, 1962

By Nelson Severinghaus

Mineral fillers have been defined as inert materials that are included in a composition for some useful purpose. Because this definition and the scope of this review are not specific- indeed, exceptions abound-accurate total statistics are unavailable. One source estimates the total production in the United States in 1971 at 5 million tons valued at $200 million, averaging $40.00 per ton. Included are a broad group of minerals-asbestos, barite, bentonite, calcium carbonate, clays, diatomite, feldspar, micas, silica, talc. Additional references will be made to synthetic mineral-derived fillers such as aluminum hydrate, precipitated calcium carbonate, and pyrogenic and precipitated silicas and silicates. A section on related uses at the end of this chapter covers absorbents and filters. Mineral fillers can be included in compounds to accomplish a variety of final results. Hardness, brittleness, impact strength, compressive strength, softening point, fire resistance, surface smoothness, electrical conductivity, and a host of other physical characteristics may be modified by the inclusion of fillers. These effects are the result of properties of the fillers, including chemical activity, hardness, particle size, shape and distribution, surface structure, color, density, and refractive index. To facilitate an overview of the mineral filler industry, this chapter will review the general usage of fillers, the inherent characteristics that intensify their utilization, and similarly their manufactured characteristics. Major using industries will then be examined in detail. Specific information on deposits and processing for industrial minerals will be found in the appropriate commodity chapter. The chart in Table 1, updated from the 3rd edition of Industrial Rocks and Minerals, illustrates the major mineral fillers (both natural and manufactured) and their more important end uses.

Jan 1, 1975

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe&apos;s love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd&apos;s register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe&apos;s love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd&apos;s register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943

By S. M. M. Safvi, A. Jowett

Small-scale continuous flotation tests are described in which the influence of 1) pulp density and 2) feed rate on the rate of flotation are investigated. The results provide further evidence of first-order kinetics for flotation and indicate that tests at different feed rates provide a particularly simple method of determining rate constants. Flotation kinetics are discussed in general terms. Over a period of many years numerous research workers have studied the rate of recovery of valuable materials from flotation pulps with a view to deter-mining the mechanism of the froth flotation process. Froth flo ation is fundamentally a collision process involviug at some stage collision and then mutual attachment between air bubbles and mineral particles. It is possible to draw analogies therefore between the flotation process involving mainly macroscopic particles and the ordinary processes of chemical reaction kinetics involving collisions between atoms, molecules and ions. By adopting this analogy we may postulate a general equation representing the kinetics of the flotation process: -dC/dt =K.CC ,Aa (1) The rate constant, K, will be a complex function involving reagent concentrations, particle and bubble sizes, induction times and no doubt flotation cell design. However, these are factors which can be kept constant in any series of experiments, permitting investigation of the exponents a and c, which determine the order of the reaction occurring in flotation. The various research investigations carried out so far have all aimed at evaluating a and c and in the majority of cases only since the concentration of air has usually been kept constant in a series of tests, so that a relationship of the following type has been investigated: -dC/dt = K1 Cc (2) The techniques of both batch testing and continuous testing have been used to investigate this relationship. The technique of continuous testing, in which steady-state conditions are established, permits direct investigation of the above equation. In the case of batch testing, C is decreasing continuously

Jan 1, 1961

MEMBERS, JUNIOR MEMBERS, ASSOCIATES AND JUNIOR ASSOCIATES LIST OF MEMBERS ALPHABETICALLY ARRANGED EXPLANATION OF SYMBOLS ** Junior Member. t Associate. || Junior Associate. Members are not marked. Capital letters signify Honorary membership. Student Associate and Rocky Mountain members on pages 165-167. Abadilla. Quirico A Catanawan. Tayabas, P. I. Abbey. Robert Graham. District Mgr The W. W. Sly Mfn. Co., 60 Church St New York. N. Y. Abbott. A. N Mines Supt Mazapil Copper Co Ltd . .Conception del Oro. Zac., Mexico. Abbott. Ckrence E Mgr Mines & Quarries, Tenn. Coal. Iron & R. R. Co 1242 Brown Marx Bldg Birminrham. Ala. Abbott. Louie Benjamin. Chief Enar Consolidation Coal Co Elkhorn Div .Jenkins, KY. Abeel. Gsorge H Jr., Cons. Min. Enar .Box 427. Santa Monica. Cal. Abel. Albert E Asst. to Pres Valley Mould & Iron Corp Hubbard. Ohio. Abel. Raymond L. Asst. Prof., Dept. of Pet. Refin Univ. of Pittsburgh Pittsburgh. Pa. Abernathy. George Elmer. Prof. of Geol. & Min Kansas State Teachers College. Pittsburg. Kans. IlAbernethy. D. Carl, Jr. Min. Engr Hudson Coal Co .Scranton. Pa. Abey, Hiroshi. Min. & Met. Engr., Min. & Met. Dept., The Higher Technical School, Osaka. Japan. tAbarn, Robert H Instructor in Met Harvard University Cambridge, Mass tAbozeid,Mahmood. Pet. Production E r . . Marland Oil Co. Ponca City, Okla. Abraham. Arthur W Geol., Richfield Oil Co Box 788. Bakersfield, Cal. Abraham, W. E. V Member, Staff of Burmah Oil Co Ltd. Nyaunghla. Upper Burmz, India. Abrahams. Alexander I Gen&apos;l Mgr., Racon Electrical Co Slough, Bucks England. tAbrahammn. C. W Min. Engr The Mond Nickel Co Ltd . Coniston, Ont Canada. IlAbmn. Guy W., Asst. Metallographist, Youngstown Sheet & Tube Co., Research Dept., Youngstown. Ohio. Abstein. Henry T., Engr. & Mgr Profile-Tamarack Mines Co . .Yellow Pine, Idaho. tAcker. E. O&apos;C Met I28 East Washington Lane. Germantown, Philadelphia. Pa. Ackerman. D. E Met. Research Lab International Nickel Co Inc Bayonne. N. J. tAbckerman. Ernest R Pres., Lawrence Portland Cement Co . .Plainfield. Union Co N. J. ||Ackerman. George F Jr. Min. Engr El Potosi Min. Co. .Apt. 13. Chihuahua, Chih Mexico. Acres, T. H Geol. Dept Valuation & Pet. Engr., Richfield Oil Co. 655 S. Flower St Los Angeles. Cal. Adachi. Jinzoo Address Wanted. Adair. Arthur C Valuation Enar., Internal Revenue. Treasury Dept., Washington, D. C. Adam. John. Min. Ennr., The Zinc Corp. Ltd., Box 4 C. Broken Hill, N. S. W Australia. Adami. Arthur E V. P Montana State School of Mines.Butte, Mont. Adami. Charles J Min. Ensr St. Joseph Lead Co 4540 Lindel Blvd., St. Louis, Mo. Adams. C. W.729 South Normandie St LaGranada Apt Los Angeles, Cal. Adams. Cmyler Geerwwd. Minn. Adams. F. J Gen&apos;l Anent. Gulf Production & Pipa Line Cos .Fort Worth. Tex. ADAMS. FRANK DAWSON. Logan Prof. of Geology and Dean, Faculty of Applied Science, McGill Univ Montreal. Que Canada. Adama, Gale L Research Enar., General Pet. Corp. of California, Higgins Bldg Los Angeles. Cal. Adams. George I, Prof. of Geol. & Mineralogy Univ. of Alabama, Tuscaloosa, Ala. Adams. H. H Cons. Geol Room 416, W. T. Waagoner Bldg Fort Worth. Tex. Adams, Henry. Cons. Min. Ennr 1050 Edgewood Ave., Plainfield, N. J. Adams, Henry H.285 Madison Ave., New York. N. Y. Adams, Henry Farnum. Engr., Charge. Experimental Work. Inspiration Concentrator, Inspiration Cons. Copper Co Box 354. Inspiration. Ariz. Adams. Huntington. Min. Enar I41 Broadway, New York. N. Y. Mama, Leland D., V. P., Leslie-California Salt Co 166 Montgomery St., San Francisco, Cal. Adams, Louis W., Illinois Steel Co .Gary. Ind.

Jan 1, 1929

By R. P. Harvey, J. E. Walstrom, A. A. Brown

In view of the large number of wells directionally drilled from offshore platforms and urban drillsites, greater interest is being focused on the directional survey and on the uncertainty inherent in calculating the position of the bottom of the hole, or other benchmarks in the wellbore. Of the two methods presented here for evaluating this uncertainty, the first is analytical and uses the principles of probability and statistics. The second method uses Monte Carlo simulation to generate a pattern of the scatter of possible bottom-hole locations. Both methods are based on a model for which the usual assumption is made that the curvilinear axis of the wellbore is adequately represented by a large number, M, of linear segments joined end to end from the top to the bottom of the hole and closely following the course of the hole. The errors due to this approximation are assumed to be negligible and are not studied here. One form of the model is to consider that for a given hole there exists a perfect set of data describing it, of the above form. Each linear segment has an angle of inclination with the vertical 7, in radians, an azimuthal angle from true north xi in radians, and a length Si, in feet. The subscript variable, i, extends from 1 to M. Each of the M linear segments representing the axis of the wellbore has three components in the X, Y, and Z directions. These components are calculated from the equations: The bottom-hole coordinates as determined from the reference set of data for the wellbore are given by the following for i = 1 to M: X=SX, Y = Sy, Z=SZ; . (2) A directional survey instrument, lowered into the wellbore to the M segments, or stations, measures the values of the 7; and the 3,. In general, because of errors from various sources, the resulting angular measurements will not be precisely equal to the 7" and xi. Random variables l, and Ai are therefore considered with associated probability density functions fi(li) and gi(Ai), respectively, which represent the distributions of potential survey measurements for this hole. Since it is assumed that the values Si are accurately measured they are treated deterministically. The random variables corresponding to the surveyed bottom-hole coordinates are given, for i = 1 to M, by:

Jan 1, 1970

THE annual meeting of the Institute was held at the Office of the Secretary on Tuesday, May 23d. President Holley appointed Messrs. J. C. Kent and Frank Firmstone scrutineers to examine the ballots of the Institute. The following were declared elected: President-ABRAM S. HEWITT. Vice-Presidents-W. P. BLAKE, E. B. (AXE, R. W. RAYMOND. Managers-R. W. HUNT, J. S. NEWBERRY, T. F. WITHERBEE. Treasurer-T. D. RAND. Secretary-T. M. DROWN. The meeting was then adjourned to June 20th. The adjourned meeting to be held in Philadelphia.

Jan 1, 1877

[59H1-Water Law and Its Significance to the Mining Industry by Wells A Hutchins 59H2-Relation of Land Subsidence to Groundwater Withdrawals in the Upper Gulf Coast Region, Texas by Leonard A Wood and A G Winslow 59F3-Hydraulic Mining of Gilsonite and Its Application to Coal Mining by J H Baker 59H4-Recovery of Phosphates by In Situ Fluid Mining by Sylvain J Pirson 59F5-Coal Cleaning Plant Design for Minimum Operating Labor by Wm M Bertholf and John D Price 59F6-Coke Combustibility A Neglected Characteristic by J D Price 59B7-Union Carbide&apos;s Uranium Operation at Maybell, Colorado by K W Lentz and F T Temple 59H8-A Rapid Method for Estimating Alumina in Feldspathic Sands by Hugh H Bein 59H9-Water Laws as Related to Dredging in Idaho by Robert A Lothrop, Richard B Porter, and Robert P Porter 58B19-Separation and Washing of Alumina Process Residue by Morton Handelman 59B11-Feed Preparation and Froth Modification for Fatty Acid Flotation by Carl C Martin and Burt C Mariacher 59B12-Design Requirements for Tailing Disposal in the Southwest by E Vern Given 59B13-Semi-Dome Shaped Buildings for Bulk Storage by Edward E Ives and William L Payne]

Jan 1, 1961

Discussion of the paper of George K. Burgess, J. J. Crowe, H. S. Rawdon, and R. G. Waltenberg, Finishing Temperatures and Properties of Rails. By Albert Sauveur, R. Trimble, William R. Webster, P. H. Dudley, George B. Waterhouse, M. H. Wickhorst, James Aston, E. F. Kenney, A. W. Gibbs, W. A. Aiken, and G. K. Burgess . . 767 Discussion of the paper of Albert Sauveur, Manganese Steel and the Allotropic Theory. By G. K. Burgess and J. E. Stead 787 Discussion of the paper of J. V. Emmons, The Surface Decarbonization of Tool Steel. By Albert Sauveur, Bradley Stoughton, E. G. Spilsbury, Oliver W. Storey, H. O. Hofman, and J. V..Emmons 790 Discussion of the paper of Richard H. Rice, Turbo Blowers for Blast-Furnace Blowing. By S. G. Valentine, W. McA. Johnson, L. Iversen, J. E. Johnson, Jr., Karl Nibecker, W. Trinks, Otto Banner, H. S. Braman, Arthur G. McKee, and Richard H. Rice . . . 794 Discussion of the paper of J. K. Furst, The Plant of the Duplex Process for Making Steel. By W. McA. Johnson, Arthur G. McKee, Henry D. Hubard, and Bradley Stoughton . . 810 Discussion of the paper of E. C. Harder, The Iron Industry in Brazil. By I. C. White and E. C. Harder 813

Jan 4, 1915