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By John C. Robison

INTRODUCTION Sensitivity analysis is a means of gauging the impact of individual risks on a financing. Key risks can occur in three time periods: - Feasibility, engineering and construction phase; - Start up phase (usually through completion); - Operating phase (post completion). If a company has agreed to cover these risks prior to completion, then less attention will be paid to the sensitivity of the project in the first two time periods. Since the operating phase of the project generates cash for both operations and debt service and generally does not begin until two to six years after the loan is signed, it is wise to look at scenarios other than the projected "base-case" scenario in order to determine the project's capability to operate successfully under a broad range of probable future events. Lenders are compensated at a fixed spread over their borrowing base and generally are not compensated if the project is successful beyond expectation. They are also subject to the loss of principal plus funding costs if the project performs below expectation. Because of this, lenders establish sensitivities around the parameters of conservative projections developed in the project feasibility studies and the cash flows resulting from these projections. The initial cash flow projections should demonstrate the project's ability to meet cash costs, debt service requirements (principal and interest), and still have sufficient cushion to cover contingencies such as strikes, price fluctuations, force majeur situations, etc. (See Schreiber, Chapter 10). The selection of the level of sensitivity analysis to be performed is the result of both objective criteria, including probabilistic analysis applied to the technical parameters, and, of equal importance, subjective criteria applied by the analysts, especially with regard to the economic and financial parameters impacting the project cash flows. RISK SENSITIVITY Assumptions used in the cash flow projections should be realistic. Risks identified by the lenders should be identified and cash flows prepared to assess whether these project risks are acceptable. Typical project risks include the following (see also Chapter 9): - Sufficient reserves - quantity and quality - Product price - Production level - Operating costs - Availability of energy and supplies - Transportation and infrastructure requirements and costs - Interest rate - Completion risks - Tax level - Political risks - Cost over-run risks - Operator experience - Management - Technological risks - Environmental permits and risks - Foreign exchange risks - Insurance coverage - Equity of sponsors - Inflation rate - Capital expenditure during project life In order to see the effect on the cash flow projections, each risk should be analyzed for its impact on the cash flow generating capacity of the project. Sensitivities can be examined to see if the resultant cash flow projection will meet the lenders minimum credit standards. 1.Reserve Sensitivity In general, lenders will not assume the reserve risk. However, it should also be noted that lenders receive loan proposals in which reserves range anywhere from proven to possible. Sensitivities are not generally run for various reserve levels and reserve estimates are either considered acceptable or not acceptable by the lenders.

Jan 1, 1985

Jan 1, 1892

[A AALSETH, EARL P GEOLOGIST. AMERADA PETROLEUM CORP. BOX 1498 BILLINGS. MONT ABADIE, HENRY G ASST TO SUP OF OPER LONG BEACH OIL DEVEL. CO. 255 S. SANTA CLARA. LONG BEACH, CALIF. ABBE. TRUMAN W. … ASST.FLD.SUP.OF PROD SUN OIL COMPANY BOX 66 STOWELL. TEXAS ABBOTT. J. L. .... GEOL. PARTNER PRITCHARD & ABBOTT 504 CENTURY BLDG. FORT WORTH, TEX ABBOTT, RICHARD H OWNER ABBOTT AND HOWARD OIL 422 W. HERMOSA DR. SAN ANTONIO, TEXAS. ABBOTT, SETH J.. JR PETR ENGR.]

Jan 1, 1961

Aamot, Olav Crone, Research Engr., Norsk Elektrokemisk Kongensgt, 18, Oslo, Norway ?29 Abbott, Clarence E., V.P., Charge of Raw Materials, Tenn. Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg., Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr., Consolidation Coal Co., Watson Bldg., Fairmont, W. Va. '15 Abel, Raymond L., Asst. Prof., Dept. of Pet. Refin., Univ. of Pittsburgh Pittsburgh, Pa. '28 Abel, Walter D., Cons. Engr 364 S. Cloverdale Ave., Los Angeles, Calif. '32 Abele, Louis T 1457 Euclid Ave., Zanesville, Ohio. '31 Abell, Leo M Sullivan Concentrator, Chapman Camp, B. C., Canada. '31 Aborn, Robert H., Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. '19 Abraham, W. E. V., East India United Service Club, 16 St. James' Sq., London, S. W. 1, England. '28

Jan 1, 1936

By R. F. Krueger

Results are presented from tests of dynamic fluid-loss rates to cores from clay-gel water-base drilling fluids containing different commercial fluid-loss control agents (CMC, polyacrylate or smt,ch), organic viscosity reducers (quebracho and complex metal lignosulfonate) and oil at several different levels of concentration. In the dynamic system the most effective individual additives to the clay-gel drilling fluid, based on cost-equalized concentrutiom, were found to be starch and the viscosity reducers. These results do not conform with the rankings determined by API fluid-loss rests, which indicate CMC, polyacrylate and starch to be the most effective and comparable. Generally, minimum dynamic fluid-losr rates were attained at cost-equalized concentrations of additive (including thinner) of about $1.00/ bbl, or less. For chernically treated clay-gel drilling fluids, both the standard and the high-pressure API filter-loss tests were found to he inaccurate indicators of trends in dynamic fluid-loss rates under the test conditions used, particulurly for drilling muds containing viscosity reducers. From a practical field viewpoint, restrictions on the applicability of the API fluid-loss test are such that it is open to question whether or not results of this test can be used routinely with confidence as an indicator of control of down-hole fluid loss under field treating conditions. INTRODUCTION The petroleum industry spends large sums of money during drilling operations to control the fluid-loss properties of drilling fluids based on the standard API filter-loss test,' which is a static filtration system. Laboratory studies' ' of dynamic filtration have shown that in a given time period filtrate loss from a circulating mud stream is greater than from a static system and that it is a function of linear mud velocity, pressure and the properties of the drilling fluid. Ferguson and Klotz' and Horner, et al," observed that (I) the dynamic fluid-loss rates for the drilling fluids used were not related to the extrapolated API filter loss and (2) the drilling fluids with the lowest API filter losses did not have the lowest dynamic fluid-loss rates. However, there has been no published information on the relative effects on dynamic fluid-loss rate as a given drilling fluid is treated with increasing amounts of chemical additive to reduce the API filter loss. Such information is economically important because drilling-fluid costs rise rapidly as chemical requirements increase. This paper presents the results of a study of dynamic filtratioi rates to cores from a clay-gel water-base drilling fluid treated with various commercial viscosity reducers and chemical fluid-loss control agents. The dynamic fluid-. loss rates to cores are compared with the standard API filter-loss values at several different levels of additive concentration. Dynamic filtration rates were obtained in each experiment under two different simulated wellbore conditions: (1) filtration just above the bit through a new mud cake laid down dynamically on a freshly drilled formation and (2) filtration up-hole through a mud cake formed by deposition of a static filter cake on top of the initial dynamically formed cake. The latter case corresponds to the bottom-hole conditions existing above the bit when mud circulation is restarted after a stand of pipe has been added or a round trip has been made to change the bit. Except for the short-duration, high-rate filtration beneath the bit where no mud cake can form, these two conditions probably represent the two extremes of dynamic filtration. Because thickness of a dynamic mud cake formed on freshly exposed formation is limited by the shearing action of the mud stream, the filtration rate for this condition is high. On the other hand, once circulation is stopped and a static mud cake forms on top of the dynamic cake, re-starting circulation has only a small effect on the cake properties and filtration rate is much lower thereafter. A discussion of the mechanics of mud-cake deposition and dynamic filtration is outside the scope of this paper but may be found in more detail in publications by prior investigators. APPARATUS AND EXPERIMENTAL CONDITIONS The test equipment used to simulate the dynamic flow conditions existing during drilling was a modification of that described previously by Krueger and Vogel: A schematic flow diagram is shown in Fig. 1. In general, a power-driven, high-pressure mud pump capable of delivering up to 60 gallmin was used to circulate drilling fluid parallel to the faces of 1-in. diameter sandstone cores mounted in a 2 3/4-in. ID high-pressure test cell. Pump rates were controlled by means of a magnetic clutch to maintain an average axial fluid velocity of 110 ft/min in the annular space between the cell wall and a 1 1/2-in. rod positioned on the center line of the cell. The core specimens were Berea sandstone plugs sealed with plastic inside 1 1/8-in. OD tubes and were fluid-saturated prior to use. Burettes were used to accumulate fluid discharged from the cores. The mud sump shown was used for treatment and storage of the drilling-fluid samples during a particular test. The valve arrangement permitted either (1) circulating drilling fluid through the by-pass line while treating with

By Maxwell Gensamer, Vsevolod N. Krivobok

It is generally recognized that "low temperatures" have a definite effect on the properties of metals and alloys. Furthermore, it is also generally understood that the effect is decidedly adverse. The possibility that the same low-temperature treatment might be employed for the purpose of improving certain properties of the alloys has received less attention until recently, and the experimental and theoretical knowledge consequently is meager. The effect of low temperatures may be studied in two ways: by studying such properties as tensile strength, hardpess, impact resistance, etc., at low temperature, and by studying the properties of alloys at room temperature after these alloys have been subjected to a low-temperature treatment. Even in the latter case, certain properties will differ materially from the same properties obtained on identical material but without cold treatment. In other words, subjecting alloys to cold treatment results in an irreversible change in mechanical properties. Changes of this character are usually indications of the appearance of a new phase or phases, and would be likely to occur in alloys which, either by virtue of their composition or by heat treatment, are retained at room temperature in a metastable condition. Consequently, studies of the effect of low temperatures logically should be conducted from the physicochemical point of view, since the results of such studies not only would furnish metallurgists with interesting theoretical data but would clearly indicate the classes of alloys that would hold promise of improvement, and, possibly, of new applications. As the present investmigation deals with chromium and chromium-nickel alloys of iron of the stainless variety, it has been thought desirable to present the data concerning low-temperature properties of these alloys, available from the most recent and most comprehensive work of H. S. Russell.l A summary of these data is given in Table 1. The data are confined to a limited number of alloys of the type dealt with in the present

Jan 1, 1931

By H. Stuart, L. Zwell, N. Ridley

specimen that was subjected to 700°C for 250 hr is shown in Fig. 2(c). The precipitates in this foil appear round and exhibit only very faint strain contrast. From this evidence, along with that described above for the symmetry of the strain field, it may be concluded that this coherent precipitate is spherical, which is generally the favored shape for coherent precipitates when the lattice parameter mismatch is small.12 These observations are consistent with the assumption that this precipitate is the y' (Ni3Al, Ti) phase. y' is known to be spherical in the early stages of precipitation. It is fcc and is similar in composition to the matrix and thus would have contrast similar to that of the matrix as do these precipitates. Direct identification of the spherical precipitate did not prove possible because of its low volume fraction and small size. The results of this investigation suggest that the increases in yield strength and the decreases in elongation observed in 45-Fe 30-Ni 20-Cr alloys containing about 0.4 pct A1 and 0.4 pct Ti on prolonged aging at 550" to 700°C are very likely due to the presence of a coherent, spherical precipitate, thought to be y'. Mi-crohardness measurements indicated that the precipitation of semicoherent M23C6 resulted in some matrix hardening. However, this precipitation process occurs much more rapidly than the changes in mechanical properties at these temperatures. 1C. L. Clark, J. J. B. Rutherford, A. B. Wilder, and M. A. Cordovi: J. Eng. Power, 1962, vol. 84, p. 258. 2 F. A. Comprelli and U. E. Wolff: USAEC Report GEAP-4745, General Electric Company November, 1964. 3C. N. Spalaris: A Monograph, USAEC Report GEAP-4633, General Electric Company, July, 1964. THERE have been many X-ray investigations of the room temperature lattice parameters of austenite which has been retained in quenched steels of various carbon contents. The results of these investigations have been collected by Wrazej,1 Wever et al.,2 and by Roberts3 and are included in Fig. 1 due to Pearson.4 The dashed line in Fig. 1 was considered by Roberts3 to most reliably describe the variation with carbon content of the lattice parameter of retained austenite. This line is given by the equation: a (Å) = 3.555 + 0.044 wt % C and recent unpublished measurements by one of the authors (LZ) support this relationship. The object of this communication is to draw attention to a relationship which describes the variation of the room temperature lattice parameter of 'equilibrium' austenite with carbon content, and which is different from that for retained austenite. The relationship a(Å) = 3.573 + 0.033 wt % C has been obtained from lattice parameter measurements made on equilibrium Fe-C austenites at elevated temperatures, which have been extrapolated to room temperature. The room temperature lattice parameter of 3.555Å which the Roberts' relationship gives for pure y-Fe is no: in agreement with the value of 3.573Å obtained when the high temperature lattice parameter data of Basinski et aL.5 and of Goldschmidt6 is extrapolated to room temperature. A linear extrapolation was

Jan 1, 1970

By R. W. Parsons

wben a displacement front encounters an isolated permeability heterogeneity, it will be perturbed. The details of this perturbation will depend on the beterogeneity size and shape, the Permeability contrast, and the mobility ratio. This paper deals with the displacement front behavior for one, simple, mathematically tractable model: a circular permeability discontinuity and unit mobility ratio. The progress of an initially planar front is shown for four permeability contrasts: k2/k1 = 0, 5/2, 2, m. The front distortion is more pronounced than streamline and isopotential distortion and it approaches a constant shape downstream from the discontinuity. INTRODUCTION The impact of reservoir heterogeneities on oil displacing processes depends upon the variation of the heterogeneous property (frequency distribution), its disposition (spatial distribution), and the inherent stability of the displacement mechanism.l The interplay of these factors plus the impracticability, if not impossibility, of describing a natural rock system in any detail makes exact displacement front movements difficult to determine. It is useful, however, to be able to qualitatively visualize what heterogeneities will do to a displacement front. In this respect certain simple models that can be treated analytically are of value. The following analysis will show the displacement front behavior for one such model. MODEL DESCRIPTION The flow field is two-dimensional and infinite in extent. The fluid flow is single phase, steady state and unidirectional at x, y = 2 m, or before insertion of the discontinuity. A circular permea- bility discontinuity is placed at the origin. Porosity and thickness are the same within and exterior to the heterogeneity. This is exactly the same model that was used by Greenkorn et al. to check analytically Streamlines as determined by Heie-Shaw flow models and finite difference computer techniques.2 FRONT POSITION CALCULATIONS The results of displacement front calculations are presented in Figs. 1 through 4 for four different permeability contrasts: k2/kl = O, %, 2, m. The times corresponding to the front locations are the Same for the 0 and cases! and for the 1/2 and 2 cases. The determination of front positions at various times is based on known analytical expressions for velocity potentials ().2 and stream functions ().2 These expressions are in terms of the x and y

Jan 1, 1969

By W. C. Ellis

Growth directions of tin, zinc, and cadmiun whisker crystals grown spontaneously fi-om the solid are summarized. In tin the edge and diagonal directions of the unit cell are jound with the exception oj- the [110] diagonal. In cadmiurn and zinc the usual dip-ections are a or a + c. The c direction has not been ohserwed. The gvouth directions from the solid are for the most part the same as those found for vapor-grozun crystals and are the ohserz:ed glide directions in plastic j-lou. Whisker crystals of these elements grown from the solid are not twinned. Specular lateral reflections are associated with planes of snall crystallographic indices. WHISKER crystals of tin, zinc, or cadmium grow spontaneously at room temperature in periods from months to years from thin electroplates and other prepared films of the respective metals.''2 It has been established that these crystals are single, but the question of twinning, such as occurs in whisker crystals of silicon,3'4 has not been resolved. Studies of morphology have been restricted to determinations of growth directions.5-' Whisker crystals are both straight and kinked. A few studies have been made on kinked whiskers including measurements of kink anglesa and determinations of growth directions,' but unfortunately not both on the same crystals. The kink angles, for the most part, for each species are grouped closely about a few unique values, but these values are not always those between observed growth directions in a single crystal. To supplement existing data, the growth directions, identification of lateral features, and presence or absence of twinning were determined with a Weissenberg goniometer by a method described elsewhereg on eight whisker crystals of tin, five of zinc, and five of cadmium. One kinked cadmium whisker was examined in detail. The specimens were needlelike, a few microns in cross section, and of the order of a millimeter in length. They were removed from electroplated substrates on laboratory specimens and commercial equipment after several years of growth as described in Table I. Since the specimens were less than 10 p in cross section they were ideally strong with no attendant risk of plastic deformation or damage in handling. Only deformation twinning has been reported for these elements. Therefore, twinning probably should not be expected in whisker crystals of these metals, particularly a twin plane containing the growth direction. A twin plane oriented in this direction was the one sought in this study. No examination was made for twinning at the boundary between kink segments except for one cadmium crystal. Well-defined reflections occur as a whisker crystal of tin, zinc, or cadmium is rotated about its growth direction when illuminated by a beam of light Although these reflections had been noted in earlier investigations, no study of them was made, probably because the earlier studies had disclosed also that

Jan 1, 1967

1938 ABERNATHY, G E Feb 6, 1948 Min & Met Apr 1948 1937 ADAMS, ARMY Aug 20, 1949 Min Eng Dec 1949 1946 ADDY, GEORGE E Sept 24, 1950 Min Eng July 1951 1920 ALDERSON, WILTON P Feb 1951 Min Eng Sept 1952 1896 ALDRICH, T H , JR May 24, 1950 Min Eng Aug 1950 1942 ALDRIDGE, LEONARD June 8, 1952Jrn Met Sept 1952 1919 ALLEN, ROLLAND C July 18, 1948 Min &Met Sept 1948 1950 ANDERSON, C P Unknown Min Eng Feb 1951 1937 ANDERSON, JOHN H May 10, 1950 Min Eng Aug 1950 1914 ANDERSON, L DOUGLASS Unknown Min Eng Nov 1951 1948 ANDRAU, E W K Oct 20, 1951 1936 ANDREWS, CHARLES B Apr 19, 1950 Min Eng June 1950 1918 ARMITAGE, PAUL June 28, 1949 Min Eng Oct 1949 1924 ARMSTRONG, PERCY A E Jan 23, 1949 Min Eng May 1949 1906 ARNOLD, CHARLES LE NEVE Aug 7, 1949 Min Eng Oct 1949 1945 ARNOLD, HAROLD S Aug 7, 1950 Min Eng Oct 1950 1936 ASH, JAMES E Dec 17. 1949 Min Eng Apr 1950

Jan 1, 1952

By N. A. Ziegler

A CERTAIN amount of interest has been indicated recently in the resistance to oxidation at high temperatures of iron-aluminum alloys (rich in iron). Hautman1 published a paper in. which some interesting results are given. According to his paper, only alloys containing at least 8 per cent aluminum indicate a marked improvement in their resistance to oxidation. At about this aluminum content, however, alloys become brittle, which considerably reduces their commercial value. About two years ago the author, performed a series of experiments, the results of which are presented here. A series of iron-aluminum-carbon alloys was prepared by melting electrolytic iron, aluminum and high-carbon iron alloy in an induction vacuum furnace.2 The list of these alloys is given in Table 1. Each alloy was forged in the ordinary way to

Jan 1, 1932

By A. M. Kivari

OPERATIONS at the cement plant of the Permanente Corporation, in the hills about 45 miles south of San Francisco and 12 miles west of San Jose, are interesting to the members because of the adoption of modern hydrometallurgical methods for handling and beneficiating raw materials. Closed-circuit grinding, classification, hydro-separation, flotation, agitation, and thickening are familiar terms at this cement plant. These methods make it possible to process refractory limestone into suitable materials for the manufacture of modern cements. Construction of the plant, having originally a design capacity of 7000 bbl. of cement per day, was started in June 1939, and the first clinker was ground on the following Christmas Day. At present the capacity is about 12,000 bbl. of finished cement per 24 hr., most of the production being low-heat cement.† About 3130 tons of limestone, 620 tons 0f clay and 100 tons of gypsum are required daily for this output. Occasionally iron oxide is added to the clay to obtain the desired composition. This, together with the gypsum, is purchased from outside sources. Up to the present time, the corporation has produced low-heat, normal, moderate heat, moderate-sulphate-resisting, high-early-strength, oil-well, modified-oil-well, and plastic cements. Most of the present production is for Shasta Dam, near Redding, Calif., the total demand being 5,800,000 bbl, of cement. Following are some of the cement requirements of the Shasta Dam specifications: [PERCENT Chemical composition: Loss in ignition2.25 Insoluble residue0.75 SO32.25 MgO5.00 Uncombined lime in clinker (CaO)1 .25 Percentage of iron oxide to alumina ratio1.5 Compound composition: Tricalcium silicate (3CaO.Si02)Not more than 3,5 Dicalcium silicate (2CaO.Si02)Not less than 40 and not more than 65 Tricalcium aluminate (3CaO.Al2O7)Not more than 7 Tetracalcium aluminoferrite (4CaO.A12O3.Fe203) Not more than 0 Fineness:] The average specific surface in the bin sampled shall be not less than 1800 sq. cm. per gram and no individual sample less than 1600 sq. centimeters. Compressive strength: The average compressive strength-in pounds per square inch of three mortar cubes composed of one part cement and 2.75 parts fine testing sand, by weight, shall be equal to or greater than the following:

Jan 1, 1941

By E. H. Lancaster, M. E. Mitchell

A MUD-conditioning program found to be very effective for drilling and completion operations on routine field wells requiring relatively short drilling time involves a moderate alkaline-tannate-bentonite treatment resulting in an ultimate filtration rate of 10.0 cc or less (API test). Mud weight schedules are planned from pressure information on completed wells in producing reservoirs and drill-stem test data obtained on other zones not being produced at present. In general, terminal mud viscosities average 45 sec (Marsh). This value has been found to be sufficient to remove cuttings from the well bore on the average well, with the slush pumps in general use on the rigs. On field wells requiring drilling times in excess of approximately 30 days, an alkaline-tannate-lime-bentonite treatment has been effective in maintaining desirable viscosities and filtration rates with a substantial reduction in chemical costs. This system has shown particular advantage on heavily weighted muds and those with abnormal flow-line temperatures. For the most part, the chemical treatment utilized in wildcat drilling follows closely the program used on field wells, depending on depth and duration of drilling operations. Wildcat mud programs are planned from information available from various geologic and operational sources, taking into consideration the possibility of encountering mud problems of a special nature in the wildcat area. Careful planning of wildcat mud pro- grams has proved to have definite value in avoiding most serious mud problems. An analysis and recommended treatment are presented on several special. mud problems which have been encountered in the area in the past. Those problems discussed are lost circulation, blowouts, sloughing shale, excessive chloride contamination, sulphate contamination, and prevention and correction of cement contamination. Introduction Drilling-mud control in the Southwest Texas area, in general, does not involve the multiplicity of problems encountered in other coastal areas. For instance, it is rare that a mixture of problems such as lost circulation, abnormal pressure, severe sloughing shale, and others, occurs on one well within close enough limits in vertical depth not to be taken care of by a sensible casing program, together with a relatively clear-cut mud program. There are conditions such as the fairly widespread occurrence of abnormal pressure in the lower Frio and Vicksburg zones, and the tendency for sloughing shale in the Jackson section which make for rather expensive mud control. However, the availability of fairly accurate geologic and operational information makes possible a reasonable degree of standardization on mud treatment over a relatively large area. It may be said that, over most of this area where drilling is currently in progress, the natural mud made is very poor in quality, but responds readily to moderate chemical treatment to yield very good wall-building characteristics. AS far as field development drilling is concerned, the mud engineer's principal job, once the routine treatment best

Jan 1, 1949

Discussion of the paper of THEODORE P. HOLT, presented at the Salt Lake meeting August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1699 to 1708. F. S. SCHMIDT, Salt Lake City, Utah.-Any furnace that can make a chloridizing roast to yield an extraction of 92 to 93 per cent. and do this at a cost of less than 24c. per ton in a 10-ton unit opens great possibilities for the treatment of certain classes of ores. This cost does not include the salt and will be reduced to about 16 1/2c. per ton in the 35-ton furnace which are now being designed. On a trial run the roaster treated 9.6 ton: of Ontario stope fillings crushed to pass a ¼ -in. opening. The ore is well adapted to chlorination with the exception of insufficient sulphur and occasional days of high lime, but is not adapted to any other process The following is an analysis of the crude ore: Ag, 9.52; Au, 0.029 oz. Pb, 0.71; Cu, 0.11; SiO, 79.4; Zn, 0.57; S, 1.00; Fe, 7.9; Mn, 0.89 CaO, 1.20 per cent. The composition of the mix was: Per Cent. Dry crude ore : 83.4 Moisture 4.4 Salt 8.3 Coal dust 2.3 Pyrite, 70 per cent. pure 1.6

Jan 11, 1914

By John Hall

THE Fremont test for measuring the energy consumed in breaking a notched bar of steel is not so well known in this country as it deserves to be. The test specimen used in this test is about 3/8 by 1/4 by about 1 1/4 in., notched with a hack saw on the lower side to cause the piece to break at a fixed point. A weight of 10 kg. falling 4 m., and provided with a knife or chisel which strikes the specimen, breaks the test piece by impact. The residual force in the falling weight after it has broken the specimen is recorded by a suitable device, and the difference between the total energy and the residual energy of the weight (in kilogrammeters) is the force consumed in breaking the specimen. An experience of several years with the Fremont testing machine has shown its great value in readily detecting brittleness not revealed by tensile testing or slow bending testing. I this paper it is proposed to discuss (1) the supersensitiveness of the test as applied to cast steel and (2) its value in revealing the effect of heat treatment under certain conditions. .

Jan 7, 1913

By E. T. Turkdogan

In this theoretical paper, a transport-reaction mechanism is suggested for the enhancement of the rate of vaporization of metals, or other materials, brought about by the process of convection and condensation. Based on theoretical reasoning it is predicted that, when there is a temperature gradient surrounding the heated object, a slight increase in the rate of vaporization brought about by natural convection is enhanced further as a result of condensation of the vapor close to the surface of the object. In order to derive the effective vapor-concentration profile, consideration is given to the super saturation of the vapor necessary for the homogeneous nucleation of the condensed phase from the vapor. For the formulation of the rate equation based on this mechanism, adequate information should be available on the transport properties of gases and vapors at elevated temperatures and the method of calculating nucleation pressures of the vapor. The methods of deriving such data are discussed in the paper and a rate equation is calculated for the vaporization of iron in helium for various temperature gradients in the boundary layer. Considerations are also given to the effect of oxygen on rates of vaporization of metals under isother ma1 and nonisotherma1 conditions. THE study of the methods of enhancement or retardation of basically transport-controlled vaporization reactions is of theoretical interest with possible practical implications. There are several ways of bringing about such effects. For example, Turk-dogan, Grieveson, and Darken1 demonstrated that the rates of vaporization of metals under isothermal conditions were increased by several orders of magnitude, up to the maximum rate attainable in vacuo, by introducing some reacting gas into the inert atmosphere surrounding the metal. Such an effect is brought about by the interaction of the counter-diffusing reacting gas and metal vapor in close proximity of the metal-gas interface. Another case which is often experienced in practice is that of vaporization affected by natural convection. Although several theoretical and experimental studies of this problem have already been made, no detailed consideration has been given to the possible effects of condensation of the vapor in the boundary layer on vaporization rates, which constitutes the subject matter of this paper. BASIC CONCEPT OF ENHANCED DIFFUSION-LIMITED VAPORIZATION When a heated object, for example a metal sphere, is submerged in a fluid medium, heat is transferred from the surface of the object to its surroundings by four simultaneously occurring transfer processes: i) free-molecular conduction at the gas-solid interface over the distance equal to the mean free path of the gas, ii) conduction and convection through the fluid-dynamic boundary layer, iii) latent heat of mass transferred, and it!) radiation. The free-molecular conduction becomes pronounced only when the total pressure in the system is very low, e.g., below 1 mm Hg. Therefore, this term may be neglected for ordinary pressures. At low mass-transfer rates, due to vaporization of the object, the contribution of process iii) to the heat transfer can also be neglected. Finally, since the temperature profile is not affected by radiation, the latter need not be considered. The natural convection is brought about by gravitational body forces arising from a decrease in the

Jan 1, 1964

By Pablo Hadzeriga

Great Salt Lake brine was subjected, in laboratory scale, to conditions simulating solar evaporation. Solid phases and the variation in composition of the liquid phase throughout the potassium salts crystallization zone are presented. These experimental results are discussed and compare with stable equilibrium data of the quinary system Cl-, SO4, Na+, K+, Mg + + and H2O. The Great Salt Lake brine in Utah is a vast reserve of several potential chemicals which has attracted much attention in the recent past. From the standpoint of an ore reserve, it may be said that the lake contains a low grade ore which has to be concentrated by evaporation of water. Because of the fairly favorable weather conditions in the Great Salt Lake area, it seems reasonable to consider solar evaporation as an economical means of concentration. From the view of phase chemistry, the main constituents of Great Salt Lake brine make it belong to the five component system: C1-, SO4=, Na+, K+, Mg++ and H2O. Because of their low concentration, the presence of other elements may be regarded as having little effect on the equilibrium of the five main components. Equilibrium data for the quinary system of our interest has been available for many years. Using these data, it is possible to calculate how the brine of the lake will concentrate when subjected to solar evaporation. In practicing solar evaporation, the weather factor and supersaturation conditions cannot be ignored, but their introduction into calculations using equilibrium diagrams is almost an impossible task. With the experimental work presented in this paper, an attempt is made to compare the stable equilibrium data of the quinary system as applied to the case of the Great Salt Lake brine and the dynamic equilibrium when that brine is subjected to continuous solar evaporation. Sea water brine belongs to this quinary system when only the major constituents are considered. The study of this system has been carried on since the last decades of the nineteenth century. The reason for these intensive studies was to give a geological explanation to the underground potash deposits. AS a result, many theories were presented trying to relate the equilibrium data with the geological formation, paragenesis and metamorphism of these deposits. Two main approaches were followed for the equilibrium studies of this quinary system. One of them, and the best known to us, was the school started in Germany in the last century by J. H. Van't Hoff. The other one, which started about the same time, was the school of N. S. Kurnakov in Russia. Both approaches were different and as a consequence generated opposite theories about the geological formation of potash deposits. The Van't Hoff school studied the quinary system of sea water under careful laboratory control, resulting in stable phase diagrams. During these studies, Van't Hoff recognized the difficulties in crystallizing some double salts.' ". . . . we unexpectedly found that some compounds whose formation in the solutions under investigation was possible at 25°C, nevertheless totally failed to put in an appearance. These, not to mention the calcium salts, were leonite, MgSO4 . K2SO4 4 H2O; kainite, KC1-MgSO4 . 3 H2O; and kieserite, MgSO4 .H2O. Even exceedingly slow crystallization with the addition of the compounds themselves did not remove the condition of supersaturation in the case of these bodies." However, those salts (leonite, kainite, and kieserite) were included in the stable phase diagram at 25°C as shown in Fig. 1 using D'Ans data.3 The figure also shows the sequence of crystallization of the Great Salt Lake brine according to the stable diagram. In later studies by the Van't Hoff school, especially by D'Ans,3 Karsten,4 Autenrieth,5,6 attention

Jan 1, 1968

NEW MEMBERS The following list comprises the names of those persons who became members during the period Oct. 10, 1918, to Nov. 9, 1918. ALLER, FRANK D., Copper Met., Ore Purchaser, American Smelt. & Refin. Co., 120 Broadway, New York, N. Y. AVÈRY, PAUL W., Met. Engr., Esperanza Min. Co., Apt. 8, El Oro, Mex., Mexico. BAKER, CHARLES A., Leaching Foreman, Copper Leaching Plant, Anaconda Copper Min. Co., Anaconda, Mont: BREED, CHARLES H Met., Crown Cork & Seal Co., Baltimore, Md. CHASE, R. L., Min. Engr 102S First National Bank Bldg., Denver, Colo. EICHELBERGER, FRANK, Vice-pres. and Engr., New York-Montana Testing & Engrg. Co., Helena, Mont. GESTER, G. C., Geol., Standard Oil Co. of Cal., 616 Standard Oil Bldg., San Francisco, Cal. GRIFFIN, JOHN, Mgr., Anthracite Territory, The Dorr Co., Board of Trade Bldg., Scranton, Pa. HAYNES, ELWOOD Pres., The Haynes Stellite Co., Kokomo, Indiana. Hsi, T. C:.. Sec'y, Tayeh Iron & Steel Works, Tayeh, China. HYDE, AUSTIN T., Mgr., Keokuk Plant, River Smelt. & Refin. Co., 607 Franklin St., Keokuk, Iowa.

Jan 12, 1918

By G. Sachs

THE iron-rich iron-nickel alloys have at-tracted considerable academic interest in recent years. The carbon-free alloys are of minor practical importance, but they are Atomic per cent nickel FIG. I. FIG. 2. FIG, I.-HONDA'S AND MERICA's IRON-NICKEL DIAGRAM, FIG. 2.-MARSH'S IRON-NICKEL CONSTITU-TIONAL DIAGRAM. the base of many alloys with various out-standing properties. The iron-nickel alloys, therefore, have been investigated exten-sively regarding both their structures and their properties. The researches on these alloys up to 1938 have been collected and critically reviewed by J. S. Marsh,1 and will be discussed in some detail in the sec-tions of this paper dealing with specific subjects. These numerous investigations have not succeeded in establishing the equilibrium conditions in this system. Alloys containing more than a certain amount of nickel (8 to10 per cent Ni) undergo the allotropic transformation extremely sluggishly, both on heating and cooling, showing a large hysteresis,2 which is not dependent upon

Jan 1, 1940

By Sherwin F. Kelly

MANY baffling problems of crustal geology-of warping and folding, elevation, subsidence, and great dislocations of the earth's surface-may now be on the verge of yielding to the science of geophysics. Electric, magnetic, gravitational, geothermal, and seismic methods are being turned to the gathering of geological evidence buried by deep layers of rock, or lying beneath the waters of the oceans. In this hope, B. L. Miller expresses the opinion that these geophysical studies will sup- ply useful data bearing-on some of the more theoretical problems of North American geology. Among these for example, is the explanation of how Appalachia disappeared. This ancient land mass is supposed to have foundered beneath the Atlantic Ocean after the close of the Paleozoic era and the question arises, was it warped or faulted downward? The geophysical data, though meagre, indicate that the surface of the dense, basal rocks, the probable remnant of ancient Appalachia now underlying the Continental Shelf, slopes downwards to a depth of some two miles below sea level at a distance of 140 mi. from shore: thus suggesting that the subsidence was the result of warping downward rather than abrupt faulting.

Jan 1, 1938