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By F. W. Bloecher, A. M. Gaudin

THIS paper describes the results of a series of tests carried out to determine the partition of dodecylamine between distilled water and the surface of quartz at various concentrations of dodecylamine acetate in solution. An adsorption-column technique was utilized for this purpose. Ralston and Harwood, of Armour and Co., had synthesized marked dodecylamine acetate for us.' In their preparation which we employed, 0.0007 pct of the total carbon was the radioactive isotope, carbon fourteen. Unmarked dodecylamine acetate of high purity was also prepared by them for our use. The presence of carbon fourteen in the dodecylamine enabled us to analyze quantitatively for dodecylamine on the surface of quartz, using a radioactive-tracer technique. The method used was that known as internal gas counting of carbon dioxide, formed by oxidation of the amine. This method has already been described, "3 ' and the reader is referred to these papers for details of the analytical method and procedures. and surrounding liquor, a technique analogous to chromatographic columns was utilized. The experimental setup is shown in fig. 1. The dodecylamine-acetate solution was made up in a volumetric flask and poured into the glass funnel shown. It was allowed to drip slowly onto the quartz bed, the rate of flow from the funnel reser- voir being controlled by a hose clamp. The quartz column was contained in a small, fritted-glass filter (size 20 mm, C). The beaded top edge of the filter was cut off to enable the holder and contents to fit into the open end of the 30/45 joint on the combustion tube. This combustion tube is used in the analytical train described in a previous paper.' A piece of gum-rubber tubing joins the bottom of the fritted-glass filter to a filter flask, which in turn is connected to a vacuum line, or water aspirator. The rate of flow of amine solution through the bed was

Jan 1, 1951

By F. W. Bloecher, A. M. Gaudin

THIS paper describes the results of a series of tests carried out to determine the partition of dodecylamine between distilled water and the surface of quartz at various concentrations of dodecylamine acetate in solution. An adsorption-column technique was utilized for this purpose. Ralston and Harwood, of Armour and Co., had synthesized marked dodecylamine acetate for us.' In their preparation which we employed, 0.0007 pct of the total carbon was the radioactive isotope, carbon fourteen. Unmarked dodecylamine acetate of high purity was also prepared by them for our use. The presence of carbon fourteen in the dodecylamine enabled us to analyze quantitatively for dodecylamine on the surface of quartz, using a radioactive-tracer technique. The method used was that known as internal gas counting of carbon dioxide, formed by oxidation of the amine. This method has already been described, "3 ' and the reader is referred to these papers for details of the analytical method and procedures. and surrounding liquor, a technique analogous to chromatographic columns was utilized. The experimental setup is shown in fig. 1. The dodecylamine-acetate solution was made up in a volumetric flask and poured into the glass funnel shown. It was allowed to drip slowly onto the quartz bed, the rate of flow from the funnel reser- voir being controlled by a hose clamp. The quartz column was contained in a small, fritted-glass filter (size 20 mm, C). The beaded top edge of the filter was cut off to enable the holder and contents to fit into the open end of the 30/45 joint on the combustion tube. This combustion tube is used in the analytical train described in a previous paper.' A piece of gum-rubber tubing joins the bottom of the fritted-glass filter to a filter flask, which in turn is connected to a vacuum line, or water aspirator. The rate of flow of amine solution through the bed was

Jan 1, 1951

By W. R. Hibbard

Although extensive pole figure studies have been reported by Brick1 and others2,3 showing preferred orientations in rolled and annealed 70-30 alpha brass, and by Hermann and Sachs4 in 70-30 alpha brass cups, comparatively little information has been published on textures in drawn 70-30 alpha brass tubes. Crampton5 reported a (110) , [111] texture in drawn brass tubes based on selected individual X ray photograms following the method of Norton and Hiller,6 but the extent and ease of developing this texture and the annealing texture have not been reported and pole figures of these structures were not found in the literature. The present investigation was further stimulated by the possible influence of textures on the mercury stress-corrosion cracking of brass tubes. According to Snoek,7 iron-nickel alloy sheet with a strong cubic texture was more resistant to corrosion than a randomly oriented sheet. Crampton5 reported that single crystals of 70-30 alpha brass drawn into tubes did not crack after 24 hr in a standard mer-curous nitrate test. Edmunds12 found that single crystals of 70-30 alpha brass did not crack in a standard mercurous nitrate test but did crack when subjected to ammoniacal vapor. Wasserman11 reported a similar failure of a single crystal of brass in ammonia. A tube with a strong texture might approach single crystal behavior and tend to resist mercury cracking if the differences in orientation between adjacent grains were sufficiently slight. Preparation OF Specimens Crampton's5 tubes drawn 28 pct reduction in area developed a slight degree of preferred orientation while in tubes drawn 48 pct it was more marked. Based on this information, in order to obtain specimens with markedly different degrees of preferred orientation but with the same final draw, two sets of 70-30 alpha brass tubes were made following the mill schedules shown in Table I. The final draw involved a large reduction in outside diameter, and a ratio of reduction in area to reduction in outside diameter similar to that reported by Crampton,5, 10 to cause mercury cracking of brass tubes. The brass contained 71.31 pct copper, 0.01 pct lead, 0.01 pct iron and zinc by difference. Determination of Pole Figures A 6-in. length from each tube was rotated rapidly by an electric stirrer in 25 pct nitric acid until the gauge was reduced to 0.003-0.005 in. The tubes were carefully cut longitudinally and the walls gently flattened. They were further etched in 25 pet nitric acid to 0.0015 in. thickness and (111) pole figures were determined using copper K-alpha radiation in the manner described by Brick.' The three general types of pole figures

Jan 1, 1949

By W. R. Hibbard

Although extensive pole figure studies have been reported by Brick1 and others2,3 showing preferred orientations in rolled and annealed 70-30 alpha brass, and by Hermann and Sachs4 in 70-30 alpha brass cups, comparatively little information has been published on textures in drawn 70-30 alpha brass tubes. Crampton5 reported a (110) , [111] texture in drawn brass tubes based on selected individual X ray photograms following the method of Norton and Hiller,6 but the extent and ease of developing this texture and the annealing texture have not been reported and pole figures of these structures were not found in the literature. The present investigation was further stimulated by the possible influence of textures on the mercury stress-corrosion cracking of brass tubes. According to Snoek,7 iron-nickel alloy sheet with a strong cubic texture was more resistant to corrosion than a randomly oriented sheet. Crampton5 reported that single crystals of 70-30 alpha brass drawn into tubes did not crack after 24 hr in a standard mer-curous nitrate test. Edmunds12 found that single crystals of 70-30 alpha brass did not crack in a standard mercurous nitrate test but did crack when subjected to ammoniacal vapor. Wasserman11 reported a similar failure of a single crystal of brass in ammonia. A tube with a strong texture might approach single crystal behavior and tend to resist mercury cracking if the differences in orientation between adjacent grains were sufficiently slight. Preparation OF Specimens Crampton's5 tubes drawn 28 pct reduction in area developed a slight degree of preferred orientation while in tubes drawn 48 pct it was more marked. Based on this information, in order to obtain specimens with markedly different degrees of preferred orientation but with the same final draw, two sets of 70-30 alpha brass tubes were made following the mill schedules shown in Table I. The final draw involved a large reduction in outside diameter, and a ratio of reduction in area to reduction in outside diameter similar to that reported by Crampton,5, 10 to cause mercury cracking of brass tubes. The brass contained 71.31 pct copper, 0.01 pct lead, 0.01 pct iron and zinc by difference. Determination of Pole Figures A 6-in. length from each tube was rotated rapidly by an electric stirrer in 25 pct nitric acid until the gauge was reduced to 0.003-0.005 in. The tubes were carefully cut longitudinally and the walls gently flattened. They were further etched in 25 pet nitric acid to 0.0015 in. thickness and (111) pole figures were determined using copper K-alpha radiation in the manner described by Brick.' The three general types of pole figures

Jan 1, 1949

By D. R. Mitchell

MEETING for the thirteenth time in New York as part of the five-ring circus known as the Annual Meeting A.I.M.E., the Coal Division experienced a wartime boom in attendance. Technical sessions were crowded and whereas 65 seats were set up for the annual luncheon meeting of the Division over 100 members showed up, many of whom had to be fed elsewhere. Possibly the Coal Division should adopt "13" as its lucky number. Discussions at technical sessions, formal and informal, were lively. Those papers containing material directly concerned with the war, or containing information that might be usable for war industries, were enthusiastically received. Some criticism was made in regard to the present method of handling discussions and it was suggested that better success would be had in getting discussions in the record by the use of hired reporters. This is being considered by the executive committee of the Coal Division.

Jan 1, 1943

By Oscar Weiss

An aerial magnetometer survey was carried out by the author's geophysical organization over the Vrede-fort dome, where Witwatersrand beds are wrapped around a granite plug 25 to 30 miles in diameter. The well-known magnetic shales of the Lower Witwatersrand system (to be referred to as LWW) give strong negative anomalies over the out-cropping portion of the dome. This is unusual as these same shales cause positive anomalies over large areas near Johannesburg and along a strike of 130 miles between the East Rand and Klerksdorp. It is suggested that the negative polarization is caused by heat and stresses connected with the doming. This negative polarization of sedimentary beds, which usually cause positive anomalies, is a good example of how "magnetic lows" can be caused by "structural highs." Significant magnetic anomalies should be tested by gravity and seismic methods irrespective of the sign of the anomalies. South of the line X — Y (see Fig 2 and 5) the gravity anomalies are smaller over the LWW beds and magnetic anomalies suddenly become weaker and even change signs by becoming positive. This peculiar phe- nomenon is explained by faulting which truncated the nearly vertical LWW shales at depth. In this manner the mass of the LWW beds has been reduced together with the weakening of the negative magnetic anomalies by positive poles which occupy the truncated end. Furthermore, by uplifting the beds between f1 and f2 (Fig 2) positive polarization becomes predominant, thus causing positive magnetic anomalies. General The Vredefort dome is one of the internationally known geological structures, which, among others, has attracted the attention of numerous American geologists. It was for this latter reason that our aerial magnetic results over this structure were selected by us for publication in the United States of America. A full description of the exposed geology has been published by Nell and readers are referred to this paper, which is subject to only slight modifications inasmuch as the subdivision of the Witwatersrand system (to be referred to as WW system) is concerned. The Vredefort dome is about 60 miles southwest of Johannesburg. The WW system, after being exposed in the vicinity of Johannesburg, plunges with southerly dips beneath the Vent-ersdorp and Transvaal systems. Along a section southwest from Johannesburg, as shown diagrammatically in Fig 4, we see no outcrops of the WW system until the Vredefort dome, where the Upper and Lower WW system are wrapped around an almost circular arc of a granite mass. Here the whole WW system is overturned around the perimeter of a huge granite plug 25 to 30 miles in diameter. Less than half of the circumference of this dome is exposed; the rest is covered by Karroo dolerites and sediments. The determination of the exact shape of the concealed part of the dome has been a matter of considerable interest and obviously geophysical methods were eminently suited for obtaining this information. A good start was made with a gravimeter survey carried out by the Geological Survey of the Union of South Africa.2 Our own

Jan 1, 1950

By Oliver Bowles

TO keep pace with technical progress is an important function of any industry. All branches of mining may learn important lessons by observing progress made in other branches. The non-metallic mineral industries may learn much from each other as well as from the metal miner and the metallurgist. Recent technical advances which have come to the attention of the Committee on Non-metallic Minerals are presented herewith for consideration and comment. It is planned to present this review for open discussion at the February, 1931, meeting of the Institute. Comments will be welcomed either in the form of written or oral discussion. It is desired that new developments not covered in this paper be brought up at that time. Some notable advances have been made in cement technology. Recognition is now being given to the advantages of closed-circuit grinding of cement raw materials in wet-process plants, with stage removal of the fine materials, It increases mill capacity, reduces the wear of grinding media, and also reduces the power requirement. The method is well known in metallurgical plants, and its acceptance by cement companies is another illustration of the lessons the non-metallic industries may learn from the metal industries. Closed-circuit dry grinding has also proved advantageous for both raw materials and clinker.

Jan 1, 1931

By Robert Peele

TWO outstanding members of the Institute will be honored at the Annual Meeting this month: Robert Peele, who will accept his election to the small group of Honorary Members; and Clinton Hoadley Crane, president of the St. Joseph Lead Co. and William Lawrence Saunders Medalist for 1936. Eminence in the profession character, interest in Institute activities, and general recognition as a gentleman and a friend by so many people, have contributed to the election of Professor Peele. The Saunders Medal is for "achievement in mining." In awarding it to Mr. Crane the citation reads "For distinguished achievement in the successful development and operation of low-grade lead mines."

Jan 1, 1936

By J. Burns Read, S. Tour

It is the purpose of this paper to summarize, as far as possible, the metallurgical information and experience gained by the Ordnancc Department, during the war, in the manufacture of artillery cartridge cases, to describe the tests to which artillery cartridge cases were put, and to summarize the knowledge and experience gained in this testing. The authors wish to acknowledge the aid given by manufacturers, army officers, and civilian employees of the Department in obtaining data. Artillery cartridge cases are cold drawn from circular disks punched from strips of rolled brass. The rnanufacture involves from 25 to 30 main operations, which are done almost entirely on a punch press. Descriptions of the operations have appeared in various periodical:: and, therefore, will not he given here. After each cupping, or drawing, operation, except the last, the cases are annealed at from 540" to 650" C. (1000" to 1200°F.), to remove all the hardening stresses set up in the metal and to allow complete recrystallization. After each annealing, the cases are pickled in niter cake or sulfuric-acid solution and then washed in water to remove all traces of acid. In some instances, the cases arc then immersed in a cyanide-salt solution, and afterwards rinsed in water, to remove the thin layer of copper that forms on the surface of the cases during the acid pickle. The last cold-drawing operation is followcd by the heading operation which, by flattening the head of the case on the outside, causes the metal to flow on the inside to approximately the proper finished dimensions. The mouth, or open end, is then annealed at 430" to 450" ('. 1800" to 900" F.) by immersion in a salt bath or by gas flames. After being washed, the eases are tapered, when they arc ready for machining, inspection, and testing. Cartridge-case Disks Good disks of proper composition and physical properties are essential to the production of good cartridge cases. The Ordnance Department

Jan 1, 1923

By J. Burns Read, S. Tour

It is the purpose of this paper to summarize, as far as possible, the metallurgical information and experience gained by the Ordnancc Department, during the war, in the manufacture of artillery cartridge cases, to describe the tests to which artillery cartridge cases were put, and to summarize the knowledge and experience gained in this testing. The authors wish to acknowledge the aid given by manufacturers, army officers, and civilian employees of the Department in obtaining data. Artillery cartridge cases are cold drawn from circular disks punched from strips of rolled brass. The rnanufacture involves from 25 to 30 main operations, which are done almost entirely on a punch press. Descriptions of the operations have appeared in various periodical:: and, therefore, will not he given here. After each cupping, or drawing, operation, except the last, the cases are annealed at from 540" to 650" C. (1000" to 1200°F.), to remove all the hardening stresses set up in the metal and to allow complete recrystallization. After each annealing, the cases are pickled in niter cake or sulfuric-acid solution and then washed in water to remove all traces of acid. In some instances, the cases arc then immersed in a cyanide-salt solution, and afterwards rinsed in water, to remove the thin layer of copper that forms on the surface of the cases during the acid pickle. The last cold-drawing operation is followcd by the heading operation which, by flattening the head of the case on the outside, causes the metal to flow on the inside to approximately the proper finished dimensions. The mouth, or open end, is then annealed at 430" to 450" ('. 1800" to 900" F.) by immersion in a salt bath or by gas flames. After being washed, the eases are tapered, when they arc ready for machining, inspection, and testing. Cartridge-case Disks Good disks of proper composition and physical properties are essential to the production of good cartridge cases. The Ordnance Department

Jan 1, 1923

The total estimated production of coal in the United States during the first century and a quarter of mining is shown in Table 20. This is the total of the production of the various states already shown in the various tables, and is believed to be the first statement of this sort made. No such table prepared from limited data can be accurate, but it is the writer's opinion that the totals shown are less than those actually produced. It was thought that this study would enable a reasonably accurate account of the movement of coal down the Ohio and Mississippi Rivers to be written. The searches made have shown that at this time the data do not exist from which such a study can be made, but some of the facts collected may be useful to future students.

Jan 1, 1942

By Walter F. Gries

AN ounce of prevention is worth A a pound of cure' is an old proverb that has sometimes been forgotten in programs having to do with the health of workmen. Realization of the truth of this maxim is increasing, however, and today the iron-mining industry, with which I am particularly concerned, is becoming more alive to the prevention of illness and the conservation of health, thus decreasing the need for treatment after diagnosis has established its necessity. The healthy workman is the happy, efficient workman, and new programs tending to make him more health-minded are being put into operation. Preventive medicine is less costly than corrective medicine, to say nothing of the better results obtained. Periodic physical examinations, with close follow-up attention when required, have reduced the time lost because of illness, workmen's compensation costs, and group-insurance benefits for nonindustrial disabilities.

Jan 1, 1939

By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By R. D. Schoone, J. T. Michalak

Recovery, recrystallization, and texture development of a cold-rolled aluminum-killed steel have been studied during simulated box annealing. Two different initial conditions existed prior to cold rolling: 1) essentially all of the nitrogen in solid solution and 2) most of the nitrogen precipitated as AlN. The combined effect of nitrogen and aluminum in solid solution before annealing was to inhibit recovery and sub-grain growth at temperatures above about 1000°F and to raise the recrystallization temperature range on continuous heating at 40°F per hr from 1000"-1050°F to 1065"-1085°F. For the material with nitrogen and aluminum initially in solution there was an inhibition in the nucleation of the (001) [110] texture component and an enhancement of the (111) [110] texture component. The differences in annealing behavior mzd texture development are attributed to preprecipitation clustering of aluminum and nitrogen at subboundary sites developed by prior cold working. THE annealing of cold-worked aluminum-killed steels has been the subject of numerous investigations.'-'2 These studies have been concerned with kinetics of recrystallization, with microstructure and texture development, and with the individual and combined effects of composition, thermal history prior to cold rolling, and heating rates during subsequent annealing. It has been shown that the inhibition of recrystallization, and the development of the pancake-shaped grain and recrystallization texture characteristic of aluminum-killed steels, can be associated with the precipitation of A1N particles during a recrystallization anneal involving heating rates in the range 20" to 80°F per hr. If the AIN is precipitated before cold rolling or if more rapid heating rates are employed, the cold-rolled steels recrystallize more rapidly to an equiaxed grain structure and texture comparable to that of rimmed low-carbon steel. The retardation of recrystallization, the development of the elongated grain structure, and the pronounced (111) texture have been attributed to: 1) precipitation of A1N at prior cold-worked grain boundaries to form a mechanical barrier to grain boundary migration;' 2) precipitation on the boundaries of the growing recrystal-lizing grains as well as on cold-worked grain boundaries;'" and 3) preprecipitation clustering or precipitation on subboundaries to retard recovery, nucleation, and growth. The present study was undertaken to study in more detail recrystallization and texture development during commercial box annealing of cold-rolled aluminum-killed steels. Comparison of the annealing be- havior after cold rolling, for two different conditions prior to cold rolling, was made in an attempt to define more clearly the role of aluminum and nitrogen in forming the recrystallization texture. A) MATERIAL AND PROCEDURE The material used in this investigation was a commercial low-carbon aluminum-killed steel which was hot-rolled with a finishing temperature of about 1565"F, then coiled at about 1020°F. The composition, in wt pct, was: 0.050 C, 0.30 Mn, 0.007 P, 0.019 Si, 0.03 Cu, 0.02 Ni, 0.02 Cr, 0.045 Al, and 0.004 N. Two 4.5 by 13 by 0.078 in. sections were cut from the center section of a hot-rolled panel and one of these was reheated to provide two different conditions prior to cold rolling: low AlN: as commercially hot-rolled, with aluminum and nitrogen in solid solution; and high AlN: as commercially hot-rolled, then reheated at 1300°F for 3.5 hr to precipitate most of the nitrogen as AlN. ~etallc&a~hic examination indicated that the reheating did not change grain size nor carbide distribution (some spheroidization of pearlite was noted). Texture analysis at half-thickness level showed that both sections had the same substantially random as-hot-rolled texture. The results of check chemical analysis of each sample are given in Table I. Both sections were cold-reduced 65 pct on a laboratory rolling mill to a final thickness of 0.027 in. Cold rolling, in one direction only, was in the direction of the prior hot rolling. Specimens 1.0 by 1.25 in. were cut from the cold-rolled sheets and given a simulated box anneal in an atmosphere of 2 pct HZ-98 pct He. Specimens were heated at a constant rate of 40°F per hr from room temperature to various temperatures in the range 750" to 1300°F and cooled immediately by withdrawal to the water-cooled end of a tube furnace. The temperature in the 6-in. uniform hot zone of the furnace was controlled within 3"F. Selection of the individual specimens was made to give a random distribution of annealing temperatures with respect to location in the cold-rolled sheet. At least two specimens of each condition were annealed to the same temperature and smaller specimens for light microscopy, transmission electron microscopy, and X-ray studies were prepared from each of these. Rolling-plane sections for each of these studies were taken at half thickness. Light microscopy and transmission electron micro-

Jan 1, 1969

By Richard O. Carlson

Ions of p31 and B 11 were implanted in natural insulating diamond macles. The thin (-0.4µ) layers showed sheet resistances of 107 to 1011 ohm per sq and activation energies of 0.17 to 0.34 ev above room temperature. However, no Hall effect could be measured, indicating that mobilities were less than I to 10 sq cm per (v-sec). Such low mobilities may be due to excessive scattering due to radiation damage in the bombarded layer or to very high concentrations of active compensating impurities. Annealing did not materially change the room -temperature properties, but the temperature was limited to -800°C by surface graphitization, the latter process probably being accelerated by lattice damage in our diamonds arising from the ion bombardment. A weak n-type thermoelectric power was detected after p31 irradiation, but it cannot be presumed that we have made the phosphorus ions active as donors in diamond. The natural diamonds have a high and uncontrolled concentration of impurities and, when coupled with the radiation damage and graphitization problems, would appear to seriously limit the quality of semiconductor that we can presently achieve by ion implantation in diamond. ALTHOUGH diamonds are usually thought of as insulating in terms of their electrical conductivity, it was found about 15 years ago that natural semiconducting diamonds do occur rarely, and these were designated as type IIb diamonds. These p-type semiconducting diamonds were found to be dominated by an impurity level 0.37 ev from the valence band. Evidence today based on correlation of the concentration of acceptor states from Hall effect measurements with the impurity concentrations determined by neutron activation analysis point to aluminum as the dominant acceptor impurity.' The compensating donor is believed to be nitrogen, which has a donor level 1.6 ev above the valence band.' However, only a small fraction of the total nitrogen content in the diamond is electrically active. An infrared absorption band at 7.8 p and ultraviolet absorption near 4 ev have been associated with nitrogen, the former providing a quantitative measure of nitrogen content.3 The nitrogen content is -l020 cm-3 in insulating or type I diamonds, but is less than 10'' in natural semiconducting diamonds. Much of this nitrogen is distributed in platelets oriented in (100) planes and not atomically dispersed in the diamond lattice.4 Semiconducting diamonds have been deliberately formed by incorporating impurities into the graphite charge in the high-pressure apparatus used to form diamonds.5 These manufactured semiconducting diamonds are always p-type, and while some show the 0.37 ev level due to aluminum, most such samples have been ascribed to impurity banding effects.6 The best natural or manufactured semiconducting diamonds have hole mobilities near 1500 sq cm per (v-sec) at room temperature, and those with the 0.37-ev level can be analyzed to reveal an acceptor concentration of 3 to 8 X 1016 cm-3 and a donor concentration 3 to 10 times lower.' NO bulk n-type diamonds have ever been reported, but the electron mobility has been measured as 1900 sq cm per (v-sec) by irradiating a diamond with ultraviolet to excite electrons out of the deep nitrogen donor level or other levels.7 New hope for the formation of n-type diamond has emerged from the ion-implantation method whereby desired impurities are introduced into a crystal lattice by bombardment with a high-energy beam of the impurity ion. It was found in the case of silicon that the usual donors such as phosphorus and arsenic and acceptors such as boron and gallium could be implanted into silicon. Wentorf and arrow' produced semiconducting layers on diamonds by an ionic bombardment in a glow discharge at potentials of about 2 kv. The observed typeness from thermoelectric probing seemed to depend on the atmosphere gas (nitrogen, argon, or hydrogen) rather than on the electrode material, but the nature of the conduction process in the thin damaged surface layer is completely unknown. A Russian group under Vavilov has attempted high-energy ion implantation in natural diamonds using boron and lithium ions9 and later also phosphorus, aluminum, and carbon ions.10 Their papers claim n-type layers from lithium, phosphorus, and carbon implant and a p-type layer from boron and aluminum implant, though the methods of type determination are not described in detail. Under government contract support, the Ion Physics Corp. has studied ion implantation in several semiconductors. While the bulk of their study1' was devoted to the irradiation of silicon, they did carry out a short study on boron and phosphorus implantation into natural diamonds. They did observe surface conducting layers but did not determine the typeness of the layers. For our experiments, phosphorus and boron were chosen as the dopant ions because of their respective donor and acceptor behavior in germanium and silicon. Moreover, they are the lightest mass dopants of the shallow level donors and acceptors from columns 111 and V of the Periodic Table (excluding nitrogen which is already present in diamond), and will have the largest depth penetration into the diamond lattice. EXPERIMENTAL Diamonds. As the target diamonds for our ion implantation study, we chose commercially available macles, which are flat, twinned diamond crystals. By scanning through the stock of a wholesale distributor

Jan 1, 1970

By E. W. Davis

If the tonnage of merchantable iron ore remaining in the Lake Superior district is divided by the average of the annual shipments for the past 20 years, it will be found that this ore supply will be exhausted in approximately 35 years. This computed exhaustion period would be an indication of the future activities of the iron-mining industry if it were not for the fact that merchantable ore is being manufactured from low-grade ore, of which there is an almost inexhaustible supply in the Lake Superior district. It is true that at present only the simplest of these low-grade ores are being concentrated to any considerable extent, but progress is being made with the treatment of the more complex ores, and now, in addition to 20 washing plants on the Mesabi Range, three plants are equipped with jigs for the treatment of ore that cannot be concentrated simply by washing. The latest addition to the ore-treating plants of the Mesabi Range is a magnetic roasting and concentration plant at Cooley, Minn., in which ore that cannot be concentrated either by washing or by jigging is roasted to the magnetic state and concentrated on magnetic separators. This plant is beginning its third season of operation, and while it is too soon to make definite predictions, there are strong indications that this new process may make commercially possible the manufacture of high-grade, merchantable iron ore from large quantities of low-grade ore now considered worthless. After the iron oxide contained in an ore has been converted to magnetite, almost any desired grade of concentrate can be produced, using magnetic-concentration equipment of the types now in general use for the concentration of the natural magnetites of New York, New Jersey and Pennsylvania. The conversion of hematite (Fe203) to magnetite (Fe3O4) is easily accomplished by heating the ore to a dull red temperature in a reducing atmosphere. The reaction is slightly endothermic, and while it requires 200 B.t.u. to heat to 900' F. one pound of hematite ore containing 45 per cent Fe, it requires only 100 B.t.u. to convert the oxide into magnetite. In the laboratory, using small quantities of ore, this conversion is very simple, but large furnaces suitable for commercial

Jan 1, 1939

By E. W. Davis

If the tonnage of merchantable iron ore remaining in the Lake Superior district is divided by the average of the annual shipments for the past 20 years, it will be found that this ore supply will be exhausted in approximately 35 years. This computed exhaustion period would be an indication of the future activities of the iron-mining industry if it were not for the fact that merchantable ore is being manufactured from low-grade ore, of which there is an almost inexhaustible supply in the Lake Superior district. It is true that at present only the simplest of these low-grade ores are being concentrated to any considerable extent, but progress is being made with the treatment of the more complex ores, and now, in addition to 20 washing plants on the Mesabi Range, three plants are equipped with jigs for the treatment of ore that cannot be concentrated simply by washing. The latest addition to the ore-treating plants of the Mesabi Range is a magnetic roasting and concentration plant at Cooley, Minn., in which ore that cannot be concentrated either by washing or by jigging is roasted to the magnetic state and concentrated on magnetic separators. This plant is beginning its third season of operation, and while it is too soon to make definite predictions, there are strong indications that this new process may make commercially possible the manufacture of high-grade, merchantable iron ore from large quantities of low-grade ore now considered worthless. After the iron oxide contained in an ore has been converted to magnetite, almost any desired grade of concentrate can be produced, using magnetic-concentration equipment of the types now in general use for the concentration of the natural magnetites of New York, New Jersey and Pennsylvania. The conversion of hematite (Fe203) to magnetite (Fe3O4) is easily accomplished by heating the ore to a dull red temperature in a reducing atmosphere. The reaction is slightly endothermic, and while it requires 200 B.t.u. to heat to 900' F. one pound of hematite ore containing 45 per cent Fe, it requires only 100 B.t.u. to convert the oxide into magnetite. In the laboratory, using small quantities of ore, this conversion is very simple, but large furnaces suitable for commercial

Jan 1, 1939

By Forrest K. Pence

BENTONITE deposits are known to occur in Texas within the Jackson group of formations. This group represents the uppermost Eocene age sediments found in the coastal plain area of Texas. It outcrops across this area of the state in a narrow band of some 4 to 20 miles width. The outcrop pattern roughly parallels the present Gulf of Mexico shore line and is some 100 miles inland from the Texas shore, Fig 1. The principal bentonite deposits are found in the areas where this outcrop pattern cuts across the south-central Texas counties of Karnes, Gonzales, and Fayette. In these deposits, the better quality bentonite is found in the lower or bottom layers of the volcanic ash deposits in which they occur. Some of these better quality bentonites develop very light colors upon firing and therefore justify their being classified as "white firing." The deposits in Karnes and Gonzales Counties apparently occur in commercial quantity, whereas the white firing strata so far uncovered in Fayette County have been too thin to be classified as yet as "commercial." A study of the ceramic properties of the weathered ash in Gonzales and Karnes Counties was reported in 1941.1

Jan 1, 1949

THE hall of the Western Iron and Nail Associations having kindly been placed at the service of the Institute, the opening session was held at 3 o'clock, Tuesday afternoon, May 13th, with an attendance of about one hundred and twenty-five members. Mr. William Metcalf, of Pittsburgh, read an address of welcome on behalf of the Local Committee of Arrangements, to which President E. B. Coxe responded. The following papers were then read and discussed : Regenerative Stoves; a Sketch of their History and Notes on their Use, by John M. Hartman, of Philadelphia. Some Curious Phenomena Observed on Making a Test of a Piece of Bessemer Steel, by William Kent, of Pittsburgh. On the Use of Determining Slag Densities in Smelting, by Thomas Macfarlane, of Wyandotte, Michigan. After the reading of these papers each member was presented by the Local Committee with a schedule of excursions, a specially prepared map of Pittsburgh and surroundings, and a directory of industrial works, all tastefully bound, and also with a metal badge bearing the seal of the Institute, to be worn on the excursions. The second session was held on Tuesday evening. The following persons, duly proposed for members and associates of the Institute, were, on the recommendation of the Council, unan¬imously elected. (In this list are included those elected at the final session on Friday morning.) George Bartol, - Cleveland, Ohio. Luther S. Bent, - Steelton, Dauphin Co., Pa. Octave Chanute, - New York City. Albert H. Childs, - Allegheny, Pa. Theodore Cooper, - New York City. Andrew Cosgriff, - Brewster, Putnam Co., N. Y. William B. Crocker, - New York City. Henry M. Curry, - Pittsburgh, Pa. Charles Davis, - Allegheny, Pa. Henry F. De Bardeleben, - Birmingham, Ala. Herbert Du Puy, - Pittsburgh, Pa. Charles L. Fitzhugh, - Pittsburgh, Pa. W. S. Franklin, - Ashland, Md. F. G. Fricke, - Pittsburgh, Pa. Paul A. Fusz, - St. Louis, Mo. Ignatius Hahn, . Pittsburgh, Pa. Henry Hargreaves, - South Pittsburgh, Tenn.

Jan 1, 1880