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By Ming-Kao Yen

A considerable amount of work has been reported in the literature in regard to the texture and earing behavior of copper strip. The rolling texture of copper has been confirmed as (110) [112] and (112) [111], which yields ears of a drawn cup at the position 45" from the rolling direction.1-3 The recrystallization texture has been established as the cubic or (100) [001] texture, where the earing positions are at 0" and 90" to the rolling direction.4-8 It has also been reported that in the development of cubically aligned grains of copper strips, the percentage of this cubic texture increased with an increase of final reduction and final annealing temperature.8,9 A comprehensive study on H.C. copper (British commercial copper of high-conductivity quality = Cu 99.95 pct, O2 0.03 pct, Ag 0.003 pct, Fe 0.005 pct and Pb < 0.001 pct) was made by Cook and Richards.6 They concluded that the recrystallization textures could be described as one or more of the following textures: (1) a single texture (100) 10011, (2) a twin texture (110) [112] and (3) a random orientation, depending upon the previous history of the specimen concerned. The effect of various alloying additions in copper was reported by Dahl and Pawlek.10 They found that certain alloying additions, such as 5 pct Zn, 1 pct Sn, 4 pct Al, 0.5 pct Be, 0.5 pct Cd, or 0.05 pct P suppressed the formation of cubic texture. Brick, Martin and Angierll reported that the cold rolled textures due to various additions fitted a rather simple pattern. However, the recrystallization textures were subject to very considerable variations. In the discussion of this paper, Baldwin stated that deoxidized copper containing 0.02 pct P gave a complicated recrystallization texture at lower temperature. When this copper was annealed at high temperature, a single texture appeared which was described as (110) [ill] but. according to a pri- vate communication from Baldwin, this orientation reported was in error and should have been reported as (110)[112]. He also reported that the earing positions of drawn cups were at 60" to the rolling direction.12 Recently, Howald, in his discussion on the paper by Hibbard and Yen,13 reported that the rolling texture of phosphorus deoxidized copper, containing from 0.006 to 0.020 pct phosphorus, was of the pure copper type. When these coppers were annealed at lower temperatures, they exhibited a random orientation, and when they were annealed at higher temperatures they had a mixed (111)[110] and (100)[001] texture, depending on the severity of the final reduction and annealing temperature. However, the specific influence of phosphorus and other impurities on the recrystallization textures and the deep drawing properties of copper strip has not been thoroughly reported. Therefore, an attempt has been made in the present work to determine the rolling and recrystallization textures and also the earing behavior of five types of commercial copper and thereby to evaluate the effect of phosphorus and some other significant impurities on the development of texture for cold reductions of about 87 to 89 pct. Materials Used The five types of copper employed in the present investigation were two phosphorus deoxidized coppers of different phosphorus content (0.007 and 0.013 pct P), an oxygen-free copper (OFHC), an electrolytic tough-pitch copper, and a fire-refined tough-pitch copper. These materials were subjected to a thorough spectroscopic and chemical analysis. The designations and the chemical compositions were as shown in Table 1. The coppers, FA1, FA2 and FA3. were hot-forged from 3-in. billets into a ½ X 6-in. plate and cold rolled to the ready-to-finish gauge indicated below. FA4 and FA5 were hot rolled and scalped to ready-to-finish gauge. The grain size of all the materials in the ready-to-finish condition was about 0.030 to 0.045 mm. Table 2 shows the last stage of the production schedule for each copper strip used. Experimental Procedure ANNEALING, GRAIN SIZE AND HARDNESS DETERMINATIONS Specimens of each type of copper were finally annealed in air for periods of one hour at temperatures ranging from 300 to 1600°F and were subsequently cooled in air. The average grain diameter of the annealed specimen was estimated by comparing with a standard grain size chart. Hardness was determined on the Rockwell 15 T scale. CUPPING TESTS Cups were made in a blanking and drawing set, in which blanks of 2-in. diam were drawn to a cup of 1.25-in. diam with an average depth of about 0.75 in. The clearance between the punch and die was about 0.032 in. The ears of the cup were measured with a special fixture which read the height of ears to one-thousandth of an inch on every ten-degree interval along the circumference of the cup. POLE FIGURES The usual transmission diffraction method with unfiltered copper radiation was employed to determine the pole-figures of the specimens cold-rolled or annealed at 900°F. All the pole-figures were derived from the positions of intensity maxima on 111 diffraction rings of the X ray photo-grams taken at 10 rotation of a

Jan 1, 1950

By Y. A. Chang

Phase relationships in the system Cr-Si have been established based on the melting point, X-ray, metallo-graphic, and DTA studies. The three intermediate phases, Cr3Si, Cr5Si,, and CrSi,, melt congruently at 177V ± I@,Cr3Si, 1680"i 20°, and 1490" *20°C, respectively, while the fourth intermediate phase CrSi, melts peritectically at 1413" i 5°C to Cr5Si3 and a melt containing 51 at. pct Si. The temperatures and compositions of the four eutectic isotherms occurring in this system are given below: DTA and metallographic evidences indicate that Cr5Si, undergoes a phase transformation at 1505" i20°C. The high-temperature form of this phase could not be retained by the quenching techniques used in this study. TECHNOLOGICAL interest in the developing of composite systems, consisting of Sic on the one hand as a fiber-reinforced material and metallic substances such as chromium, nickel, or Cr-Ni alloys as a binding agent on the other hand, stimulated the present investigation of phase relationships in the binary system Cr-Si. Earlier works concerning this system have been evaluated and summarized by ansen and Anderko.&apos; Their phase diagram was based mainly on the works of Kieffer, Benesovsky, and schroth2 and Kurnakov.~ According to these authors, the three intermediate phases Cr3Si, CrSi, and CrSi, all melt congruently at approximately 1730°, 1600°, and 1550°C. However, they did not agree on the compositional stability of the fourth intermediate phase between Cr3Si and CrSi. Later Parthe, Nowotny, and schmid4 determined the structure of this phase to be tetragonal T-1 type using the single-crystal method, and concluded that this phase had a formula of Cr5Si3. Since the compilation of Hansen and Anderko,&apos; a new phase diagram for the system Cr-Si has been proposed by Elliott5 based on the works of Goldschmidt and rand,&apos; Guseva and ~vechkin,~ and Trusova, Kuzev, and Ormont8 and the earlier works quoted by Hansen and Anderko.&apos; According to this proposed phase diagram, all four intermediate phases have large ranges of homogeneity and all melt congruently. More recently, Svechnikov, Kocherzhinskii, and yupkog studied the system Cr-Si by the DTA-method. According to their findings, the three intermediate phases, Cr3Si, Cr5Si3, and CrSi,, melt congruently at 1700°, 1720°, and 1475"C, respectively, while the fourth intermediate phase, CrSi, melts peritectically at 1475°C to Cr5Si3 and a melt containing 50 at. pct Si. The temperatures and compositions of the four eutectic isotherms were found to be: In view of the discrepancies existing in the literature concerning the system Cr-Si, it was decided to rein-vestigate the phase relationships in this system. EXPERIMENTAL a) Starting Materials. Chromium disilicide and chromium or silicon powders were used in the present study to prepare the melting point and DTA samples. CrSi, was obtained by directly reacting cold-pressed elemental powders in an atmosphere of Hz at a temperature of about 1250°C. Chromium powder, purchased from Stark Chemical Co., had the following impurities in ppm: Fe, 200; Mg, 1000; and 0, 250; while silicon powder, purchased from the Welded Carbide Co., had the following impurities in ppm: Ca, 700; and Fe, 3500. b) Melting-Point Determination and Differential Thermal Analysis. Cylindrical melting-point samples of approximately 13 mm in diam and 30 mm in length with a rectangular groove in the center were prepared by hot-pressing of well-mixed powder mixtures in graphite dies. Before the melting-point determination, the hot-pressed samples were ground on a sand paper to remove any minute surface contamination of graphite. A small hole of 1 mm in diam, drilled on the center portion of the samples, served as a blackbody cavity for the temperature measurements. DTA samples approximately 13 mm in diam and 15 mm in length were prepared in a manner similar to the melting-point samples. Melting points were determined using the Pirani technique under a helium atmosphere of 40 psi. The design, performance, and operation of this apparatus have been described in detail by Rudy and ~ro~ulski.&apos;~ The temperature measurements were carried out with a calibrated disappearing-filament-type micro-pyrometer. The measured temperature was corrected for losses from the quartz window of the melting-point furnace and for deviations from blackbody conditions of the observation hole. The procedure for temperature correction has also been previously described." The DTA method of Heetderks, Rudy and Eckertl&apos; was also used to check any phase transformations of selected alloys in the system Cr-Si. It was not possible to make remated runs on the same sample once melt-

Jan 1, 1969

By A. U. Seybolt

In part 111&apos; of this series it was shown that during the selective oxidation of a 3 1/4 pct Si-Fe alloy in damp hydrogen, only silica, (observed at room temperature) as low cristobalite or low tridy-mite or both, was formed as an oxidation product. In some in- „ stances where the film was fairly thin (probably well under 100A) there was some suggestion of an amorphous form of SiO2. The present investigation of oxidation rate showed that the selective oxidation of silicon-iron can be rather complicated, and apparently impossible to rationalize in an unequivocal manner. In some temperature regions, notably near 800" and 1000°C, the data seem to obey the familiar parabolic rate law. However, at intermediate temperatures complications were noted, some of which are possibly due to the order-disorder reaction in the silicon-iron solid solution. IN an earlier report&apos; it was shown that during the oxidation of 3 1/4 pct Si-Fe alloys in H2O-H2 atmospheres only silica films were formed in the temperature range from 400° to 1000°C in hydrogen nearly saturated with water at room temperatures, or at dew points as low as -45°C. In the work to be reported here, some observations are made on the rate of oxide film formation. As in the earlier investigation, electron diffraction patterns generally showed either low tridymite or low cristobalite or both, except for some very thin films. These sometimes showed diffuse rings, presumably due to a very small crystallite size, or in a few cases, diffuse bands probably caused by an amorphous film. EXPERIMENTAL PROCEDURE Vacuum-melted silicon iron made of high-purity materials was rolled into strips 0.014 in. thick, and cut into samples 1/2 in. wide by 1 in. long. Chemical analysis showed 3.2 pct Si and 0.002 pct C. All samples were surface abraded with 600-grit paper, were solvent cleaned, and then placed in an paper,apparatus containing a "Gulbransen type"2 micro-balance. Here the gain in weight of the samples of about 5 sq cm area could be followed as a function of time during the oxidation caused by the water in atmospheres of various controlled water-hydrogen ratios. The water-hydrogen ratios can most easily be described as varying from a dew point of 0°C (PH2O-p^2 = 6.2 x 10-3 , to K (P j -40°C (PH2O/PH^= 1.3 X 10-* Most of the experiments were conducted at the 0°C dew-point atmosphere because drier atmospheres caused so little gain in weight that the accuracy of measurement was poor. Because of this, only the data obtained at PH2O,/P,,,= 6.2 x X3 will be reported. The temperature range extended from 800" to 1000°C; and most of the oxidation runs lasted for about 24 hr. The reproducibility of any reading was about ± 1 ?, but the sensitivity of the balance was about 0.2 ?. The atmosphere, flowing at 200 cm per-min, was preheated to the furnace temperature before contacting the specimen. While the gas flow caused a measurable lift on the sample, it was ordinarily sufficiently constant so that it was not an appreciable source of error. X-ray and electron diffraction checks of the samples before and after oxidation showed no evidence of preferred orientation, either on the metal samples or on the silica films formed. EXPERIMENTAL RESULTS The data obtained are summarized in Table I, and some are given in detail in Figs. 1 to 4. In the fourth column of Table I, kp refers to the parabolic rate constant in the expression (?/cm2)2 = kpt + c [1] where ? = micrograms gain in weight kp = parabolic rate constant in units r2 /cm4 t = time in minutes c = constant It will be noted that in many cases no value for kp is given; this is because in these instances the data did not obey the parabolic rate law. The silica film thicknesses given in the last columns are values calculated from the weight gain, an average tridy-mite-crystobalite density, and by assuming a perfectly plane surface. Fig. 1 shows the data plotted in the form of Eq. [I], hence a linear plot indicates parabolic behavior. It has been frequently observed in the literature that

Jan 1, 1960

By J. C. F. Randolph

New Granada, or, as it is known to its people, the Republic of Colombia, occupies the northwest corner of South America, and includes the Isthmus of Panama. Although it is one of our nearest neighbors, so little is known about it in the United States that the following notes regarding it, flowing from a year&apos;s professional residence, may be timely. It is bounded on the north by the Caribbean Sea and Costa Rica, on the east by Venezuela and Brazil, on the south by Brazil and Ecuador, and on the west by the Pacific Ocean. Its extreme geographical limits are from 2&apos; South latitude to 12&apos; North latitude, and from 69 to 78&apos; East longitude. In size, therefore, it is roughly 1000 miles from north to south, and 600 miles from east to west. After many political convulsions and revolutions, and a somewhat checkered history, the country consists to-day of nine departments, Panama, Bolivar, Magdalena, Cauca, Santander, Antioquia, Tolima, Boyaca and Cundinamarca. These departments are governed from the national capital of Bogota, although each has its own capital and departmental staff. The total population of the Republic is not more than 3,000,000 inhabitants, and these to a large extent consist of mixed races. Those who live in the hot belt are, as a

Jan 1, 1890

By Alan R. Grant

The Cascade Range of Washington can be considered metallogenetically to be primarily a copper province. Structural and chemical data compiled from examination of numerous copper occurrences in the Cascades indicate a marked parallel of physical conditions for sulfide deposition. In probable order of significance, the environmental criteria are as follows: 1) adjacent or subjacent, postregional metamorphism high-level intrusive activity, most commonly in the time range from 15 million years to 30 million years; 2) transverse northeast trending structural belts which obliquely cut the northwest regional trend of the range; 3) potassium-silica wall rock alteration; most important of the alteration suite of silicates are orthoclase secondary biotite and quartz; 4) the intersection of northwest trending and northeast trending structures. The varying geologic environments in the Washington Cascades present a complex setting for the sulfide deposits. The North Cascades are comprised of predominantly pre-Tertiary metamorphic rocks invaded by Tertiary calcalkaline intrustive rocks. The Central Cascades, lying south of the North Cascades, exhibit a younger, higher level geologic environment comprised of predominantly early to middle Tertiary volcanic rocks and subordinate sedimentary rocks which are intruded by Tertiary calc-alkaline igneous rocks. Although the Tertiary Cascade intrusions are dominantly quartz dioritic, copper mineralization is commonly found in rocks of quartz monzonite to granite composition. These acid rocks appear to be the product of late stage magmatic K alteration of the original quartz diorites. Sulfide concentrations are considered to be in part dependent on the degree of K-silicate activity and the intensity of transverse structural deformation.

Jan 1, 1973

By L. D. Rickets

The principles on which an art is founded are usually few and necessarily basic in nature, but he who wishes to achieve the power to select his aides and give success to important undertakings that may be entrusted to him in the future must ordinarily undergo years of drudgery in order to gain the experience that will enable him to distinguish such fundamentals through the haze of reenforcing detail that clothes and tends to disguise them. This especially applies to those who would dream dreams that may come partly true. Professor Henry B. Cornwall of Princeton was a graduate of Freiberg with mining experience in Mexico. He was my friend and mentor during my college life. In 1883 I finished my postgraduate course and had two offers of work to consider. His advice is very clear in my mind today. It was essentially as follows: I know something of the mines of Mexico and have crossed through the mountains of the West. The West possesses a vast area of mountain and valley. California has long had its gold mines, the Comstock and Gilpin County followed and now comes the discovery of Leadville. I believe the West, will become a great mining country. You can choose now to teach here or go to the mountains. Were I in your place I would go West and identify myself with mining.

Jan 1, 1932

By K. U. Snowden, J. N. Greenwood

CRACKS which form in lead exposed to fluctuating stress frequently follow a rectangular pattern. It is well known that under ordinary atmospheric conditions these cracks are intercrystalline. On the other hand after fabrication the crystal grains in lead are in general irregular polygons. The observed facts appear to be mutually contradictory. Re-examination of some lead failures has confirmed that the rectangular cracks are intercrystal- line. It follows therefore that under fluctuating stress some of the grains lose their irregular outlines and become approximately regular polygons of cubic type. G. R. Gohn and W. C. Ellis* suggest that this is due to recrystallization during the life of the part, in such a way that the new grain boundaries are aligned at 45 deg to the longitudinal strain prior to the formation of the fatigue crack. Experiments at Baillieu Laboratory—Some recent experiments carried out in the Baillieu Laboratory in conjunction with the Broken Hill Associated Smelters have thrown some light on this transition. A test piece of pure lead was polished chemically

Jan 1, 1959

By S. Frederick Ravitz

FOUR liquids are ordinarily present in the lead blast furnace during lead smelting. At the bottom is the lead bullion, which is metallic lead containing about one per cent of impurities, including gold, silver, copper, bismuth, arsenic and antimony. Above this is the speiss, which consists essentially of arsenides and antimonides of iron and copper. The speiss is followed by the matte, which consists principally of sulfides of iron, copper and lead1. The top layer is the slag, of which the major constit-uents are silica, lime, alumina, zinc oxide and iron oxide. Similar products are obtained from the dross furnace, which treats the dross obtained in decopperizing lead bullion. The distribution of gold and silver among these various products is of considerable importance in the smelting of lead. In general, the matte and speiss cannot be treated in the lead smelter, and usually are sent to a copper smelter. It is usually desirable, therefore, to keep their gold and silver contents as low as possible, and to collect the precious metals in the bullion. If the bullion, speiss, matte and slag exist together in equilibrium, the gold and silver should distribute themselves among these four liquids in a definite manner, which, other conditions being equal, should depend only on the amounts of gold and silver in the charge to the furnace. It is thus apparent that a knowledge of whether such equi-librium exists is necessary before attempting to study the effects of various compositions of matte and speiss on the distribution of gold and silver among the furnace products2. Moreover, systems consisting of four liquids in equilibrium are very rare, and are of considerable scientific interest.

Jan 1, 1936

By Edward H. Robie

IN many ways, the Annual Meeting of the Institute in February was the most successful yet held. Attendance surpassed even that of the 75th Anniversary Meeting in 1947 with its international flavor. The number of technical sessions and the number and quality of papers presented almost certainly set a new record. The banquet was the best attended of any yet held even though the price reached a new high. Despite the demand for almost 1700 tickets to the banquet, some felt that the price-$13.50-was higher than they could afford. There are two points of view: One is that this is the big social event of the year for members and that it is worth from three to five dollars more to have it at the Waldorf and to have a luxury menu, as we did this year, with turtle soup, a fish course, guinea hen for the entree, and wild rice (which we understand is $3.50 per lb) for a vegetable. The other point of view is that a seven or eight dollar banquet of more simple food at the Commodore Hotel would more than make up in appeal, especially to the younger and less well-heeled members, what it would lack in glamour.

Jan 1, 1952

After months of negotiations, the U. S. has agreed to buy between 6000 and 7000 long tons of Bolivian tin now stockpiled at Peruvian and Chilean ports, at $1.175 per lb, f.o.b. South American Ports. Harry A. McDonald of the Reconstruction Finance Corp. signed the contract with Victor Andrade, Bolivian ambassador. The Mercantile Metals and Ore Corp., of New York City, acted as the agent of Bolivia&apos;s Banco Minero in negotiating the deal. The contract is a short term one. Throughout the talks, the U. S. refused to make a long term agreement because of the possibility that Bolivia will soon nationalize its mines. The Bolivians desired to sell the U. S. 18,000 tons during a one-year pact. The price agreed upon is roughly the same as with Malayan producers. In the meantime, American Smelting & Refining Co., signed over control of its operations to the Bolivian Government. The formal act of leasing the mines to the Bolivian Government follows the announcement last July by the company that it was closing operations because of high costs. Contract terms were not disclosed.

Jan 1, 1952

By Richard E. McElvain, I. Cave

The selection of centrifugal pumps for mill discharge duty should be based on the total circuit concept. The practice of operating the mill circuit based on limitation of the pump can result in losses in one day which would offset the pump cost. Operating data from 25 grinding circuits have been reviewed and comparative results on added mill capacity have established advantages far beyond the less significant maintenance costs with increased circulating load and better cyclone operation. Mill discharge pumps should be selected on the following basis: i) Best available design for wear performance ii) Size to provide best economic life iii) Liner material best suited to circuit conditions Pump efficiency is a secondary consideration because power consumed by pumps is small compared to mill power input. Energy dissipated in mill pumps is contributing to comminution of ore.

Jan 1, 1982

By Joseph G. Wargo

A meteoric rise in selling price has revived gold exploration activity throughout the world. In the United States the effort is, in large measure, channeled toward discovery of disseminated gold deposits such as the Carlin-type, i.e., with size and grade characteristics similar to Newmont&apos;s Carlin mine in Nevada. The subtle surface indications characteristic of Carlin-type gold mineralization have been examined by a number of geologists, and the more obvious prospects have been tested by surface sampling and drilling. It is likely that most of these readily recognizable deposits have already been found and, as a consequence, prospectors are now entering a new, second stage of exploration for Carlin-type and related disseminated gold deposits.

Jan 9, 1979

By Luther Wagoner

For a number of years I have, at odd times, tried to perfect a method of assay sufficiently delicate to find and estimate minute quantities of gold and silver. The object in view was to examine rocks remote from veins or mineral areas, in order to test the probability of the lateral-secretion theory. Having succeeded in measuring approximately the amount of gold and silver contained in one cubic centimeter of sea-water, I present a detailed account of the method employed, with some of the results obtained. General Method of Assay. The use of purified lead without other flux, blowpipe methods, extraction by cyanide, and measurement of the beads by the microscope. Purged Lead. The method of testing is by cupellation. On a properly prepared cupel, it is easy to cupel and find a bead of 0.002 mm. diameter. Such a bead of silver weighs about 1 part of a milligramme. A bead 0.02 mm. in diameter weighs about 1/24,000 mg., and a close approximation can be made to its weight. It is desirable that the lead used in the assay should be low in silver so as to avoid large correction, but as the parted

Jan 1, 1902

By S. Wiederhorn

The energy and force of interaction between a crack and a slip band have been calculated. When the distance between the crack and the slip band is greater than the dislocation spacing of- the slip band, the force on the cgrack is perpendicular to the slip band. The energy needed to propagate a crack against this force can be lawe enough to pevmit crack propagation parallel to noncleavage planes. SEVERAL recent experiments have demonstrated the occurrence of crack-slip band interaction in ionic crystals having a NaC1-type structure. Stokes, Johnston, and Lil have studied the nucleation and growth of cracks in MgO. From their observations, they conclude that slip bands have the ability to halt and stabilize cleavage crack nuclei. Gilman2 has shown that a crack, propagating along a (100) cleavage plane in a previously deformed LiF crystal, tends, at certain points within the crystal, to switch to (110) planes. He reasons that plastic deformation reduces the cohesive energy of the (110) planes below that of the (1130) planes, making possible (110) crack propagation. Keh3 has demonstrated that when indentations are made in MgO, crkcks form along (110) planes at the indentations. Gilman2 attributes the formation of these cracks to plastic cieformation. There is some doubt as to the formation of cracks on (110) planes. Kuznetsov4 in his discussion of crack propagation in rock salt, shows that splitting along (110) planes requires 1.76 times as much energy as splitting along a stepped (100) surface. Therefore, the observed (110) cracking in LiF and

Jan 1, 1962

By S. E. Piper, E. M. Buchalter, R. P. King, E. T. Woodburn

The problems involved in an optimum decision making model for flotation circuit are, first of all, to characterize the feed material in terms of parameters which can quantitatively describe the network flotation action in terms of a feasible set of control actions. Once the characterization has been postulated, it is then necessary to devise tests relating to parameter sensitivity, in order that credibility of the model predictions can be assessed. Once a credible model is available, the optimum control set is determined by a hill climbing technique. Details will be reported as to the credibility of model predictions using the stochastic flotation model on a network and further, computational problems associated with hill climbing for a complex objective function are reviewed. Discussion is presented on use of the Rosenbrock technique with constraints and use of a modified objective function with constrained derivatives when employing Fletcher and Powell technique.

Jan 1, 1969

By T. D. Yensen, N. A. Ziegler

AGING is a term that connotes a slow change in properties under ordinary operating conditions. It can be accelerated by increasing the temperature and by mechanical straining. The magnetic properties of iron and some of its alloys have for many years been known to be subject to such a change. But the cause of the change was not recognized until a few years ago after mechanical age-hardening in nonferrous alloys of the "duralumin" type had been definitely shown, by means of solid solubility curves, changes in electrical resistance and microanalysis, to be caused by slow precipitation of one or more constituents from the solid solution. The similarity between the solid solubility curves of such alloys (Fig. 1) and those for iron-nitrogen (Fig. 2) and iron-carbon alloys (Fig. 3) below the Al transformation point suggested at once that magnetic aging of iron might be caused by a similar process; namely, by the slow precipitation of carbon and nitrogen in the form of Fe4N and Fe3C at ordinary temperatures because of a cooling rate that had been too rapid to permit complete precipitation according to equilibrium conditions. This suggestion has since been amply confirmed, particularly by the comprehensive work of Köster1 on the effect of nitrogen and carbon. Typical curves are shown in Fig. 4 for the relationship between aging temperature and coercive force. Previous to the establishment of the precipitation-hardening theory it was thought that the effect of nonmetallic elements like C, N, 0, etc., on the magnetic properties of iron was greatest when these elements were retained in solid solution, atomically dispersed throughout the interstitial spaces of the iron lattice2.

Jan 1, 1935

By E. Ackerman, L. Y. Tu, S. C. Sun

The use of ultrasonics in forming emulsions is not new. As early as 1927 Wood and Loomis&apos; reported preparation of emulsions with ultrasonics. In 1935 Rschevkin and Ostrawskyz described the use of great ultrasonic power in producing fine emulsions of various oils and paraffin in water. Recently Oyama and Tanakahmployed ultra-emulsification to increase the effectiveness of sodium ethyl xanthate in flotation of chalcopyrite and galena. An emulsion is a two-phase system consisting of two incompletely miscible liquids, the one being dispersed as finite droplets in the other. The dispersed liquid is known as the internal or discontinuous phase, and the surrounding liquid is termed the external or continuous phase. There are two types of emulsions; one is oil-in-water (O/W) and the other water-in-oil (W/O). The word oil refers to the liquid other than water. Circumstances exist in which the emulsion type is not clearly defined, and the internal and external phases both contain portions of the opposite phase. This is said to be a dual emulsion. Among the many hypotheses&apos;, 6v proposed for the formation of emulsions, the Bancroft&apos;s adsorbed film or double interfacial tension theory is widely accepted. Bancroft ""educed that in the process of emulsification the interfacial tension between oil and water is lowered by the formation of an emulsifying film, which contains the adsorbed molecules and/or ions from the emulsifying agent and the two liquids.

Jul 1, 1955

By Arthur Flagg

(New York Meeting, February, 1913.) THE Elk City mining district of Idaho occupies a position near the geographical center of Idaho county, a region of mod¬erate elevation in the western foot-hills of the Bitter Root mountains. The district comprises an area of approximately 350 sq. miles, bounded oil the west by the Newsome district and on the south by the Dixie and Oro Grande districts. There are no mining districts to the north or east. Elk City, the principal town and the seat of the mining office for the district, is situated in a hydrographical basin surrounded by low hills. The elevation is 4,200 ft. above sear level. Through this basin flow Elk Creek, Red river, and American river, which unite west of town to form the south fork of the Clearwater. The one township is set out from the Bitter Root Forest Reserve. Though a railroad starting from the Stites terminus of the Clearwater Short Line of the Northern Pacific railroad has been under consideration for some years, the camp is yet with¬out railroad facilities. The projected road would follow the south fork of the Clearwater on easy grades, but would be very expensive to build and maintain. While such a road would greatly benefit those who are now operating in the camp, and in a slight degree stimulate interest in its possibilities, there is hardly business enough to warrant its construction.

Jan 4, 1913

By T. D. Yensen

AGING is a term that connotes a slow change in properties under ordinary operating conditions. It can be accelerated by increasing the temperature and by mechanical straining. The magnetic properties of iron and some of its alloys have for many years been known to be subject to such a change. But the cause of the change was not recognized until a few years ago after mechanical age-hardening in non-ferrous alloys of the "duralumin" type had been definitely shown, by means of solid solubility curves, changes in electrical resistance and microanalysis, to be caused by slow precipitation of one or more con-stituents from the solid solution. The similarity between the solid solubility curves of such alloys (Fig. 1) and those for iron-nitrogen (Fig. 2) and iron-carbon alloys (Fig. 3) below the Al transformation point suggested at once that magnetic aging of iron might be caused by a similar process; namely, by the slow precipitation of carbon and nitrogen in the form of Fe4N and Fe3C at ordinary temperatures because of a cooling rate that had been too rapid to permit complete precipitation according to equilibrium conditions. This suggestion has since been amply confirmed, particularly by the comprehensive work of Köster1 on the effect of nitrogen and carbon. Typical curves are shown in Fig. 4 for the relationship between aging temperature and coercive force. Previous to the establishment of the precipitation-hardening theory it was thought that the effect of nonmetallic elements like C, N, 0, etc., on the magnetic properties of iron was greatest when these elements were retained in solid solution, atomically dispersed throughout the interstitial spaces of the iron lattice2.

Jan 1, 1935

By Robert Carlson, Hugh McMillan

During 1967, the Metropolitan Sanitary District of Greater Chicago adopted a policy of land application as a method of using the solids produced in the wastewater treatment process. Research by the Agronomy Department of the University of Illinois, several demonstrations on farm land, reclamation of acid strip-mine spoils, fertilizing a land fill, and reclamation of an alkaline sand waste pit showed the value of using wastewater solids to reclaim marginal and submarginal lands. To launch the Solids-On-Land Program, 10,000 acres of land in Fulton County, Ill., was purchased, part of it previously strip-mined for coal. The Sanitary District initiated a water monitoring program, constructed holding basins, leveled the land, awarded a liquid fertilizer transportation contract, installed a distribution end application system, and began application and crop production. During 1972, the Sanitary District completed the first year of application and harvested the first corn crop. The corn yielded 60 bu per acre while the previous year in a demonstration field it yielded 56 and 13 bu per acre, respectively, on treated and untreated strip-mined land.

Jan 1, 1976