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AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve Engineers. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BIGELOW, BRAXTON. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BROOKS, ALFRED H., Captain, Engineer Officers' Reserve Corps. BROWNE, DE Courser, 1st Lieutenant, Ordnance Dept., Fortress Monroe, Va.

Jan 8, 1917

AARONS, J. BOYD; Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve Engineers. AMBLER, HARRY A., Second Training Camp,, Ft. Sheridan, Ill. BAINS, THOMAS M., JR., Major, Engineer Officers' Reserve Corps. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy' Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BARRETT, LESLIE P., Lieutenant, A. E. F., France. (Unattached.) BENSEL, J. A., Major, Engineers' Reserve Corps. BIGELOW, BRAXTON, Royal Engineers, B. E. F. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BOWLES, MARTIN F., 2d Lieutenant of Infantry, Camp Funston, Kans.

Jan 11, 1917

By George Otis Smith

A YEAR ago, ,at the Institute's dinner, I closed my A remarks with the words: "The scientist devotes his life to the advancement of learning; the engineer gives his to the advancement of living." May 1 begin tonight where I left off then and speak first of the distinction between science and engineering? This difference is a difference both in purpose and in method: it is the sharp contrast between theory and practice; it marks the broad gap between dream and attainment. Sometimes it happens that the investigator is also the builder and applies what he discovers, yet the distinction between science and engineering serves to point out the broad dependence of the engineer upon his brother the scientist. You remember .the old - saying that "where there is no vision the people perish" translate this into modern experience and we may say that "where there is no science, the engineer fails."

Jan 1, 1929

By C. Chiou, D. P. Seraphim

The effect of clustering on the superconducting properties of Al-Zn alloys has been studied by the ballistic induction techniques. The superconducting critical temperature, T,, changes when zinc-rich clusters are formed. The change in T, depends on the concentration and may be positive or negative, but always correlates with an effective decrease in the solute concentration of the alloy. Reversion after clustering effectively returns a 5 at. pct Zn alloy to the quenched state. These methods might be use&lly extended to the Al-Mg system, where X-ray data are difficult to obtain. In very dilute Al-Zn alloys, as in other tin,' indium, aluminum,2 or tantalums base solid solutions, there is a decrease in the superconducting critical temperature, Tc, roughly proportional to the temperature independent resistivity, i.e., -0.2°K per pS2cm. With increasing solute concentration, the T, generally reaches a minimum and then increases4 to a value well above that for the pure solvent. The change of T, with solute concentration follows an empirical formulation involving two constants which correlate with the scattering cross section of the impurities. As will be shown below, the Al-Zn alloys more concentrated than 1or2at. pct do not follow the empiricism, probably because they are unstable even when rapidly quenched.5 However, it seems possible to study at least the later stages of solute clustering by precise measurements of the 1', following various thermal treatments. A few experiments on quenched alloys, aged alloys, and tests on reversion are reported here. The heat treatments selected for obtaining the quenched and aged states were mainly deduced from the work of Dash and Fine.6 For the quenched state, specimens were homogenized at 480°C, quenched to -160°C, and immediately transferred and mounted in liquid nitrogen. Measurements on the superconducting properties and residual resistivities were then made at helium temperatures, after which the specimens were aged at room temperature for 3 to 5 hr, i.e., much longer than the time required for clustering to be essentially completed. The superconducting properties and residual resistivities were once again examined. To reach the reverted state of the A1-5at. pct Zn alloy, the aged specimen was heated for 5 min at 200°C and then tested as above.

Jan 1, 1963

By H. A. Schwartz, W. Kenneth Bock

In this paper it is shown that when the tensile strength of a given steel in various states of heat-treatment is plotted against its elongation, a straight line results. The equation of this straight line can be computed with considerable accuracy from its chemical composition. The appropriate equations are given. The logarithm of the slope of the tensile-strength locus is shown to be proportional to the cumulative effect of the total alloy addition and the vosition of the line to be directly proportional to the cumulative effect of the alloy content. It is further pointed out that heat-treatment is more effective than composition in determining yield ratio. The latter enters mainly by its effect on hardenability, which is briefly discussed. Reduction of area and Brinell number are given some incidental attention. The data are applicable only to steels that have been normalized and/or quenched. The steels, if normalized, may or may not have been tempered. If quenched they must have been tempered at or above 4oo°C. (75o°F.). Introduction Cast steels vary in composition and frequently are used in various states of heat-treatment. It is obviously important to be able to predict the compositions that might accompany specific engineering properties by suitable selection of heat-treatments. For cast steels, which are of necessity produced heat by heat in accordance with the particular requirements of the castings to be poured, there has been, happily, much less tendency to standardization than for rolled products, whose destination is not necessarily known when particular ingots are made or rolled. It is of distinct advantage to the steel foundry-men to be able to make steel of given properties, using alloys that can be recovered from scrap, or most conveniently or cheaply bought, rather than a particular formula adopted in the interest of standardization. The heat-treatment appropriate to securing a given result in a given steel is well known to be closely related to composition. For example, molybdenum steels are not much softened by tempering except at rather high temperatures. Highly alloyed steels are "air-hardening," and on cooling in air behave like carbon steels that have been quenched. With these matters, we do not concern ourselves in this paper, although we recognize their importance. The entire picture evidently will be very complex and can be brought within accurate understanding only if our knowledge of test results can be coordinated in terms of general principles.

Jan 1, 1944

By H. A. Schwartz, W. Kenneth Bock

In this paper it is shown that when the tensile strength of a given steel in various states of heat-treatment is plotted against its elongation, a straight line results. The equation of this straight line can be computed with considerable accuracy from its chemical composition. The appropriate equations are given. The logarithm of the slope of the tensile-strength locus is shown to be proportional to the cumulative effect of the total alloy addition and the vosition of the line to be directly proportional to the cumulative effect of the alloy content. It is further pointed out that heat-treatment is more effective than composition in determining yield ratio. The latter enters mainly by its effect on hardenability, which is briefly discussed. Reduction of area and Brinell number are given some incidental attention. The data are applicable only to steels that have been normalized and/or quenched. The steels, if normalized, may or may not have been tempered. If quenched they must have been tempered at or above 4oo°C. (75o°F.). Introduction Cast steels vary in composition and frequently are used in various states of heat-treatment. It is obviously important to be able to predict the compositions that might accompany specific engineering properties by suitable selection of heat-treatments. For cast steels, which are of necessity produced heat by heat in accordance with the particular requirements of the castings to be poured, there has been, happily, much less tendency to standardization than for rolled products, whose destination is not necessarily known when particular ingots are made or rolled. It is of distinct advantage to the steel foundry-men to be able to make steel of given properties, using alloys that can be recovered from scrap, or most conveniently or cheaply bought, rather than a particular formula adopted in the interest of standardization. The heat-treatment appropriate to securing a given result in a given steel is well known to be closely related to composition. For example, molybdenum steels are not much softened by tempering except at rather high temperatures. Highly alloyed steels are "air-hardening," and on cooling in air behave like carbon steels that have been quenched. With these matters, we do not concern ourselves in this paper, although we recognize their importance. The entire picture evidently will be very complex and can be brought within accurate understanding only if our knowledge of test results can be coordinated in terms of general principles.

Jan 1, 1944

By E. Bicknese, R. Clark

The mechanism and rate of reduction of FeO at conditions similar to those in the stack of a blast furnace have been determined for temperatures from 980" to 1165°C. Preliminary studies of the reduction of Fe2O3 with activated coconut charcoal in a static system (no flow of reducing gas) have shown that the CO2-CO ratio of the product gas depends upon the relative reactivities of the Fe2O3 and charcoal. In a systern with a "hot blast" of CO and Nz (simitar to dry bosh gas), synthetic FeO, and actiuated coconut charcoal, the rate of reduction was not sensitive to the flow of reducing gas, and the rate-controlling step alas the chemical reaction at the metal-oxide interface. Wherz solid carbon was not present, a critical flow rate of reducing- gas had to be met in order to prevent a lowering of the reduction rate. The effect of a less-reactive carbon (blast-jurnace coke) and of a "natural" FeO on the mechanistn and rate, and the mininum amount of carbon necessary in the charge to tnaintain the reducing potential of the gas phase, have been determined. THE importance of iron oxide reduction processes has encouraged many studies of the process reaction kinetics. Despite this, the mechanism is not well-understood and three main theories have evolved, which can be stated as follows: A) the rate-controlling step is diffusion, either gaseous diffusion of the reductant or product gas through a porous solid,' or solid-state diffusion of iron and oxygen atoms through the so1id.2 B) The slow step is diffusion of reducing gas through a stagnant boundary layer. C) The reaction rate is controlled by the chemical reaction occurring at the metal-oxide interface and is proportional to the area of this interface.3 By increasing the velocity of the reducing gas to a flow rate beyond which no increase in the reduction rate is observed, critical flow rate, it may be possible to eliminate B as the slow step. However, as warnere points out, the establishment of a critical flow rate may only assure that the reaction is not limited by a reduction in the reducing potential of the gas and that B may still be the rate-determining step. Edstrom and Bitsianes and Seth and Ross8 show that A and C may both be correct for the reduction of the same oxide, depending upon the stage of the reduction, and that the relative importance of the two mechanisms varies with the porosity of the oxide. Themelis9 has derived expressions which express A, B, and C in terms of the fraction reduction, Rx, of a spherical particle. Thus, in the case of A a plot of In (1 - Rx) vs time must be linear and the time to reach a given reduction is proportional to the square of the particle diameter. For B a plot of (1 - Rx) vs must be linear and the time to reach a given reduction is proportional to the square of the diameter. For C a plot of 1 - (1 - RX)1/3 vs f must be linear and the time to reach a given degree of reduction should be proportional to the diameter. In the case of mixad controlled reactions, none of the plots are linear over their entire length. The results of previous studies, in which the rates of gaseous reduction of iron oxide were measured in the absence of carbon, may not correspond to blastfurnace practice because they ignore the effects of the Boudouard reaction. CO2 +C — 2CO The presence of carbon may alter the mechanism or the rate of iron oxide reduction through an enrichment of the gas phase by Eq. [1]. In this case, the presence of and reactivity of carbon become important. If the Boudouard reaction has no effect on the rate of reduction, the reducing gas could be supplied by some means other than the gasification of carbon at the tuyeres and carbon could, theoretically, be eliminated from the burden. Preliminary studies of the reduction of Fe2O3 with activated coconut charcoal were made to determine if the reactivity (surface area) of the Fe2O3 had any effect on the product gas composition. Two size fractions of Fe2O3 were reduced with charcoal in a static system (no flow of reducing gas). In each case the charcoal was -100 + 325 mesh and was 25 pct of the total charge. One fraction of the reagent-grade Fe2O3 was submicron in diameter. The other fraction was -100 + 200 mesh and was prepared from the former by compacting, sintering at 1300°C, crushing, and screening. In each experiment, the reaction vessel was filled with a mixture of CO and CO, which would be in equilibrium with FeO and iron at the reaction temperature. A furnace was heated to the desired temperature, the vessel was placed in the furnace, and the gaseous products of the reaction were collected and analyzed. The results of these experiments, Fig. 1, show that the gas phase associated with the submicron oxide is more oxidizing than that with the -100 + 200 mesh oxide. Therefore, in a static system, the relative rates of the reduction reaction and the gasification of carbon depend upon the reactivities of the Fe2O3 and charcoal. The reduction of FeO to iron is the most important reaction occurring in the blast furnace and is probably the slowest of the several reduction steps. The mechanism and rate of reduction of FeO in a system containing carbon and a flow of dry bosh gas have been studied. TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AlME

Jan 1, 1967

Jan 1, 1970

Jan 1, 1965

IN THE past, we have, perhaps, been somewhat careless in our furnace practice, in the use of high-grade material, lowering the production costs through demanding high-grade ores, increasing the size of units, and eliminating heat losses by collecting and returning unused heat to our furnaces. Further economies would seem to be possible through keeping out of the furnace those materials that appear to serve no useful purpose and carry with them heat that should be used in reduction operations. In the manufacture of pig iron, about three tons of inert nitrogen pass through the furnace for each ton of iron produced. This nitrogen serves no useful purpose in the chemical actions involved, but when discharged into the atmosphere it carries away a considerable quantity of heat. Can not this loss be eliminated, at least in part, through the use of more oxygen in the blast? Many metallurgical chemists, during the past 20 years, have stated that they thought it can and have urged that the plan be tried. Others have expressed doubt, not being able to visualize how more oxygen could be used in present practice; they have regarded it as impracticable, without trying to conceive of an entirely new practice based on a new reagent. That more experimental work has not been done is due to the fact that no cheap oxygen has been available, but the committee believes that there is strong reason to expect that, should a demand exist, 99 per cent. oxygen may be made at a cost not to exceed $3 per ton. The theoretical studies of the committee have indicated such marked economy by using oxygenated air in various operations that its members strongly recommend experimental work to verify the anticipated economies. The committee has developed plans for experimentally determining the effects of oxygen-enriched air on the operation of an iron, blast furnace. A furnace with a height of 30 ft. has been built and it is recommended that the plans be put in, effect as the first step in the research.

Jan 11, 1924

By Roscoe C. Clark

In a previous technical note' by Walter Rose, evidence is offered in support of the contention that "the possibility of describing oil recovery features in terms of capillary pressure phenomena has not been established entirely." It is not the purpose of this note to present further discussion of this possibility but rather to point out that the argument presented there does not appear to be generally valid. In the cited note' reference is made to the experiments of Welge2 wherein it was shown that when water was displaced by oil from a core the pressure in the water phase was less than in the oil phase but that when this oil was then produced by water drive the pressure in the water phase was greater than in the oil phase. Rose has concluded from these observations that conditions of static equilibrium did not obtain since the fluid saturations were such that phase discontinuities seemed unlikely. The argument from which this conclusion was drawn is based on the contention that "the pressure is always greatest in the non-wetting phase at each static interstitial interface of contact with the wetting phase." This premise appears to have been reached from a consideration of capillary phenomena in cylindrical tubes, although it may a1so hold for other types of pore geometry, hut as will be shown below it does not hold for all pore shapes and hence is not generally applicable. Since the pore structure of porous media such as reservoir rocks i- in general so complex as to defy exact description. it is undoubtedly of great value to establish a model in terms of pore shapes of known geometry, provided of course that the limitations of the model are recognized. That the limitations of the capillary. or cylindrical, tube model have not always been fully recognized will be evident from the following discussion of a pore of different shape hut one which may a. logically he considered a.; the capillary tube. The pore space to be considered is that shown in Fig. 1, which may be thought of as the "hole in a doughnut."* Consider the interface, A-B-A', between two immiscible fluids, P, and P2, which interface meets the solid alone a line, A-C.A'-C'. The interface A-B-A' is the surface of a spherical segmen† while the line of mutual contact be-

Jan 1, 1950

By William R. Jones, Robert M. Hernon

This report on the Central mining district of New Mexico is the partial culmination of an intensive U.S. Geological Survey effort dating back some 30 years. Robert M. Hernon went to Silver City in 1948 to finish a detailed restudy of the district that had been started in the thirties by Samuel G. Lasky. He was joined by William R. Jones in 1951, and Jones took over as project chief when Hernon resigned to do consulting work in 1953; it was under Jones' guidance that most of the work was brought to completion or nearly so ( 17, 22-24, 26-30). Hernon returned to the Survey in 1958 to work in .the southern Appalachians. Early in 1965 Jones urged that Hernon be reassigned to the Silver City project to help complete the Professional Paper report on the ore deposits of the Santa Rita quadrangle as well as to take over preparation of the report on the Central district for the Graton-Sales volume. This reassignment was approved, and Hernon began work on the present report. By late June he had completed most of it in draft form, and on June 28 Jones and Hernon left Denver for a short trip to Silver City to fill in a few gaps and to reacquaint Hernon with activities in the district, which he had not visited for 12 years. Late in the afternoon of June 29, 1965, as Bob and Bill were 85 miles short of their destination, their jeep collided head-on with a truck that was attempting to pass another vehicle in a cloud of dust. They both died instantly. As the most recent surviving member of the Silver City project (1958-1962), I was given the honorable though rather sorrowful task of putting the Hernon-Jones report "in shape" for publication. Fortunately the manuscript was already in good shape, so that the task has consisted of little more than minor reorganization and editing, and of preparation of the illustrations, abstract, and bibliography. The sections on wall-rock alteration had been left for Jones to complete in the light of his recently intensified interest in alteration geochemistry (25), and it is in these sections only that. the report may fall short, for they have been filled in from a 1958 manuscript by Jones on the ore deposits of the Santa Rita quadrangle that he intended to revise considerably. The shortcomings, however, are largely in the interpretation, not in the field data. As a brief but accurate summary of what was known about the geology of the Central mining district in 1965, this report stands as a fitting testimonial to the scientific dedication of two exceptional men.

Jan 1, 1968

By M. C. Udy, C. H. Lorig

THROUGH the years much interest has been centered in attempting to develop a direct method of iron-ore reduction, to replace or supplement the present indirect blast-furnace process. It would not be difficult to produce a list of more than 500 patents dealing with the direct production of iron and steel, but the few of this type of process that have proved successful do not produce in competition with the blast furnace; they produce special products. A survey of the literature reveals that the equilibrium conditions for the reduction reactions (iron oxides with carbon monoxide and with hydrogen) have been fairly well established but that data on the rate of reaction are discordant, although the general effects of the variables are known. This dissertation deals with the rate of reduction of a magnetite concentrate with hydrogen. The following variables have been studied: bed depth, gas velocity, particle size and temperature. The behavior of a single particle was also studied. LITERATURE Two general factors should be considered in a study of reduction of iron oxide: (I) equilibrium relations, and (2) rate of reaction. The first factor, equilibrium, has received the attention of many investigators and the equilibria Fe304-FeO-H2-H20, Fe3O4-FeO-CO-CO2, FeO-Fe-H2-H20, FeO¬Fe-CO-C02 are fairly well established. Of the second factor, the rate of reaction, much less is known. Data are comparatively scarce and there is very little concordance. The discordance probably results from the large number of variables influencing the reactions. However, the general effect of the variables is known. Among these variables are temperature, gas velocity, particle size, porosity, gas composition (distance from equilibrium), presence of impurities, greater or less prevalence of side reactions, and even design of the apparatus itself. Wetherill and Furnas1 published an excellent paper in 1934. They point out that any one or more of five processes (the chemical reaction, diffusion of the reactant through the gas film, diffusion of the reactant through the solid phase, diffusion of the reaction product through the solid phase, or diffusion of the reaction product through the gas film) may be the slow process, and thus the rate-controlling process. It is regretted that the work of these authors was limited to experiments at one temperature, and that the range of gas compositions was limited. Langmuir2 has shown that heterogeneous reactions take place at phase boundaries.

Jan 1, 1942

By Johnson Crawford, Alan H. Hoagland

Zinc mining at Jefferson City began in 1854 with small scale production of oxidized ore from open pits. Significant production began in 1913 with the development of the Mascot Mine by the American Zinc Company. In 1965, four flotation mills were treating crude ore at the rate of about 12,000 tons per day and the Mascot-Jefferson City district currently is the largest zinc producing area in the United States. The producing mines, Mascot, Young, North Friends Station, New Market Zinc, Grasselli, Davis-Bible, Coy, and the Jefferson City, are 15 to 28 miles northeast of Knoxville in the Valley and Ridge physiographic province, an area of gentle relief lying between the more rugged Great Smoky Mountains and the Cumberland escarpment. The ore is strata bound, occurring essentially within a stratigraphic range of 200 feet in the Lower Kingsport and Upper Longview formations of Lower Ordovician age. In the lower strata of the mineralized section, the ore generally is found in coarsely crystalline elastic dolomite breccia containing silica and chert debris within a sequence of aphanitic limestones. The upper strata of the mineralized section are fine-grained primary dolomites that, in the ore zones, have been fragmented in mosaic patterns by solution collapse with the interfragmental space filled by white gangue dolomite and sphalerite. The mineralogy is unusually simple, sphalerite being the only important sulfide. Pyrite is very sparse. Dolomite gangue is abundant, silica was deposited in quite small amounts, calcite is minor, and fluorite and barite are very rare. The principal ore controlling structures are rubble breccia zones that were formed during the post-Lower Ordovician-pre-Middle Ordovician erosion interval by supergene solution as a phase of the development of a regional karst system of underground drainage that extended to' depths of at least 800 feet. The major Appalachian orogenic structures are post-ore and have been superimposed on the ore bodies. There is substantial evidence to support the current thinking of the writers that the ore deposits were formed at a depth not exc1~eding 800 feet.

Jan 1, 1968

By J. R. Thompson

It is common practice, and certainly good business as all of us know, to take care of plant operating equipment. Machinery of any type requires periodic inspection and planned maintenance. With this thought in mind a plant operator should at the end of every shutdown period make regular belt inspections and plan for later appropriate care and maintenance. The points mentioned below are understood well by all of us but are sometimes forgotten because belt conveyors are comparatively easy to operate. Maintenance of any conveyor belt is dependent upon the fundamental characteristics of the two component parts-cover and carcass.

Jan 6, 1950