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By Y. H. Liu, G. W. Powell

Thin foils made from the gold-rich region of- short (0.15 mm)Au-Ag diffusion couples annealed at 880°C for 1 hr were examined in ax electron microscope and the structures were compared with that of pure gold subjected to identical heat treatments. The couples underwent Plastic deformation (bending) during the diffusional anneal. The foils prepared from the diffusion zone have a higher dislocation density and incidence of subboundaries than pure gold. The plastic bending of the couple can be interpreted in terms of the climb of edge dislocations, which are pavallel to the bend axis, along the direction of diffusion. THE interaction of lattice defects during interdiffu-sion between two metals has been considered by several investigators. In particular, da Silva and Mehl,1 Barnes,' and Bardeen and Herring3 have proposed models based on interactions between point and line defects to account for the Kirkendall effect (marker movement). Each of these models is based on dislocation climb, which can either add or remove lattice planes, induced by an under- or supersaturation of vacancies. A theoretical treatment of the nucleation and growth of voids by the condensation of vacancies has been presented by Seitz.4 Stresses can arise in a binary diffusion couple as a result of the vacancy flux and the gradient in the lattice parameter. rinkmman' has investigated the effects of diffusion-induced stresses on void formation; the results of his analysis suggest that voids can form and grow under the influence of these stresses in the absence of an excess vacancy concentration. The relationships between vacancy supersaturation and diffusion-induced stresses and void formation have been elucidated also by Balluffi and seigle6 who concluded that the stress generated by a vacancy supersaturation aids the growth of voids. Experimental evidence which indirectly shows that stresses are produced by chemical diffusion has been obtained by several researchers.2,7-9 This evidence consists in part of the observation by light microscopy of the formation of subgrains, a process characteristic of the high-temperature deformation of some metals during creep.'0 More striking, however, is the plastic bending of short (0.2 mm) Cu-Ni couples observed by Barnes2 and of boron-doped silicon crystals reported by Queisser.9 Diffusion-induced dislocations in iron and silicon have been investigated by Ainslie et a1.11and Schwutte and Queisser,12 respectively, the former using transmission electron microscopy and the latter an X-ray transmission technique. Matthews and Crawford13 observed the formation of boundaries by the climb of interfacial misfit dislocations in thin, vapor-deposited Au-Pd couples diffused in situ in an electron microscope. In order to obtain additional information on the phenomena associated with defect interaction and diffusion-induced stresses in binary couples, an electron transmission study of foils prepared from the diffusion zone of short Au-Ag couples was undertaken. The initial objective was to investigate the processes occurring at various points of the diffusion zone. Subsequent research demonstrated that foils could be prepared only from the gold-rich region of the diffusion zone using the technique described herein. EXPERIMENTAL PROCEDURE Preparation and Annealing of the Diffusion Couples. The couples were made from annealed, high-purity (99.999 pct). polycrvstalline gold and silver sheets (0.075 mm thick). Shall (0.075 by 5 by 17 mm) elec-tropolished coupons of gold and silver were pressure-bonded by heating the two metals in a graphite device to 770°C and holding at this temperature for approximately 30 min. The quality of the bond was ascertained by metallographic examination at 150 times. Each couple subsequently was annealed at 880°C for 1hr; under these conditions, the extreme portions of the

Jan 1, 1968

By J. W. Evans

ONE of the most important and frequent calculations that the extractive metallurgist is called upon to make is that of the standard free energy change of a reaction (?F°). For many reactions of metallurgical interest, the lengthy arithmetical calculations have been eliminated by the use of free energy-temperature diagrams which have been constructed by Ellingham,1 Richardson and Jeffes,2 Kellogg,3 and Osborn4 (e.g., for oxides, sulphides, halides) from critical surveys of existing data. The speed and simplicity of making calculations with these graphs make them of great practical value and, this should be stressed, in the majority of cases no greater accuracy is obtained by the individual calculations from specific heat data, entropies, and heats of reaction. With the increasing industrial application of vacuum methods to the winning of metals, notably at present magnesium and the alkaline earth metals, it is necessary to calculate low metal vapor pressures above reaction mixtures. The existing free energy diagrams usually give values where the solid and liquid metals are at unit activity. To obtain the free energy change associated with the reaction Metal (solid or liquid) = Metal (gas) it is customary to calculate this from either vapor pressure equations or from the appropriate free energy functions. This paper presents graphically the free energies of vaporization of a number of metals of economic importance which can be used in conjunction with other free energy diagrams. Certain metals have been excluded on the following grounds: titanium, tungsten, molybdenum, and platinum have very high heats of vaporization and boiling points and the uncertainty of these values arising from difficulties of high temperature measurements makes free energy values of doubtful accuracy; the data for cobalt, vanadium, and zirconium are uncertain; finally, arsenic, antimony, and bismuth could not be conveniently included. because of the presence of mixtures of polyatomic and mona-tomic vapors in the temperature range considered. Free Energy Diagram In Fig. 1, the standard free energies of vaporization per mol (?F°T) have been plotted for the temperature range 0" to 2000°C for the reaction M (solid or liquid) = M (gas) The data have been obtained from the free energy functions — (F-H298)/T for the solid, liquid, and gaseous elements and the heats of vaporization at 298°K, i.e., ?H298 (vapor). The values of these functions have been taken without change from the recent critical survey by Brewer;' the bulk of this data is from Kelley7 with adjustments in the light of more recent work. Values of the function — (F-H298) /T at T = 298°, 500°, 1000°, 1500°, and 2000°K were employed. Where possible, a further independent value was obtained by using the boiling point, i.e., where ?F°T = 0. All calculations are based on the assumption that the metal vapors are monatomic and that the boiling points refer to those temperatures at which the partial pressure of the monatomic vapor above the metal is 760 mm. For the alkali metals, e.g., sodium, potassium, and lithium, diatomic gas molecules are present as minor species; details of these are discussed by Brewer." On the basis of the above values and allowing for the change in slope at the melting point, straight line graphs were constructed and extrapolated to 2000°C. The deviation from a straight line did not exceed ±500 cal, which in all cases appears less than the probable error in the ?F°T values.

Jan 1, 1954

By John F. Brass

INTRODUCTION The Jim Walter Corporation is a Florida based organization with diverse interests. They have operations in many states and overseas, but the heart of the company is in the southeast. The major part of the corporation's business is home building and everything that is related to it. In 1969, the Jim Walter Corporation gained an interest in coal mining through the acquisition of the U. S. Pipe & Foundry Company which had two slope mines to supply its requirement of metallurgical coal. In the early 1970's it was decided to enlarge the coal mining activities and work was started on the Blue Creek project. This involved sinking four new deep mines (originally there were to have been five but it was later decided that the property could be satisfactorily worked by four mines). They are all located in west central Alabama between Tuscaloosa and Birmingham. They have a combined projected output of 7314 million tons of very high grade metallurgical coal per year to be reached by the mid 1980's. These new mines are all to work the Blue Creek seam which is a very gassy seam and in the area to be mined is found at between 45m (1500 ft.) and 731m (2400 ft.) below the surface. Longwall is the only practicable method of mining to produce the planned outputs in the conditions prevailing and each mine is planned to have three longwalls as the primary production system. Continuous miners will be used just to do the development work for the longwalls. No. 3 Mine is the most advanced of the mines and started the first longwall early in 1979. The second unit started in the middle of 1980 and the third is scheduled for mid 1981. The first longwall at No. 4 Mine is expected to commence production early in 1982. This paper attempts to relate some of the problems that have been encountered and the lessons that have been learned.

Jan 1, 1981

By B. Thomas Mansbach

INTRODUCTION The Overseas Private Investment Corporation ("OPIC") is a U.S. Government agency mandated to promote the economic development of the less developed countries ("LDCs") by assisting U.S. private investment in the Third World. Generally, investment decisions turn on the optimism or pessimism of the private sector's financial analysis of a project, with market price of product a major unknown in a very chancy set of projections. Discussions with American mineral companies, however, show that, more often than not, in developing country projects it is the political risks of investing in mineral exploration and extraction that pose the most serious deterrent to investment. In several of the projects described here, investments would not have been made if OPIC had not been involved providing support to the project sponsors and their funding sources. Clearly it is not OPIC's business to promote U.S. investment in a project which is not commercially viable, but OPIC's programs can neutralize the political uncertainties which act as disincentives to investment in otherwise commercially viable projects. That is to say, OPIC's programs are designed to reinforce market decisions and not distort them. Although OPIC is an independent agency of the U.S. Government, it is managed by a Board of Directors, the majority of whom come from the private sector. This, coupled with the statutory requirement that it be self-sustaining and operate with due regard for the principles of prudent risk management, requires that it operate on a business-like basis. Although established as a development agency, to the business public OPIC is both an insurance company and a lending institution, with two major programs which are available to U.S. investors in the minerals sector: its political risk insurance program and its finance program. Each has been specially tailored to the meet needs of the mining industry. The insurance program provides coverage against four basic types of political risk: Currency Inconvertibility, Expropriation, loss caused by War, Revolution and Insurrection and Interference with Operations as a result of an act of War, Revolution or Insurrection. Coverage against the risks of Civil Strife can be added to both War, Revolution and Insurrection coverage and Interference with Operations. Inconvertibility coverage provides protection against a deterioration in an investor's ability to convert local currency into U.S. dollars. This deterioration can be the result of either active or passive delays. Active delays consist of a change in exchange laws or regulations that leads to inconvertibility delays of 30 days or more. For example, if the exchange regulations at the time of contract execution allow an investor to transfer earnings equal to 18% of its registered capital per annum and the government of the host country later changes the law to allow conversion of only 12%, the insured would convert the 12% transferable under the new exchange regulations with the government foreign exchange authorities, delivering the remaining 6% to OPIC for conversion at 99% of the then prevailing rate of exchange. (OPIC does not cover devaluation risks.) Upon delivery of the local currency to OPIC, normally at the U.S. Embassy in the project country, the insured's account in the U.S. would be credited with dollars. Delays can also result from what is termed passive blockage, which includes administrative delays of more than 60 days (sometimes longer) caused by the bureaucratic tie-ups or pigeonholding of transfer requests, as well as delays suffered simply because the government of the host country does not have sufficient foreign exchange. The transfer procedure is the same as with active blockage - the local currency is delivered to OPIC in the project country and OPIC provides dollars in the United States at the then prevailing rate of exchange. The second coverage -- Expropriation -protects not only against the loss of the investment due to the well-known risks of expropriation, nationalization or confiscation by the host government, but also against

Jan 1, 1985

By Warnie Flint

According to statistics that have been compiled by the National Safety Council, U.S. Bureau of Mines, American Medical Association, and other agencies, accidental injuries cause more deaths than all the leading diseases. There isn't anyone who is immune to an accident. Probably the best way to describe an accident is to say that it is an unexpected happening. The automobile driver isn't expecting a terrifying crash, the electrician isn't expected to be electrocuted, nor is the coal miner expecting the roof to fall on him. All personal injuries will not result in death. There is a multitude of victims who are living proof of what accidents can mean to an individual. These are the victims who are blind, paralytic, missing arms, legs, etc. In most instances the earning power of these individuals is gone, and they are utterly dependent upon family or welfare. For many years there seemed to be an attitude that prevailed upon industrial America that accidents were inevitable, and that so many fatalities and injuries should be expected. This, of course, was utter nonsense. Since the birth of such organizations as The National Safety Council, American Society of Safety Engineers, and the U.S. Bureau of Mines, much progress has been made in reducing accidents. The enactment of compensation laws greatly contributed to the progress that has been made. Does this mean that all accidents can be prevented? Unfortunately, it doesn't. Human psychology indicates that men will work unsafely or perform unsafe acts for the following reasons: 1) Lack of knowledge or skill. 2) Conflicting motivations, such as: (a) to be more comfortable, (b) to save time or effort, (c) to be accepted by a group 3) Physical or mental condition.

Jan 1, 1973

By J. V. Gluck

In the present paper," as in earlier publications, V1'2"1 the authors present experimentally obtained relations for the free energy of solution of oxygen in various metals as a function of temperature. The relations are linear and given in slope-intercept form. The authors give values for the "probable error" of the slope and intercept, citing Birge's method17 for obtaining these quantities. Birge discussed these methods as early as the period 1929-32.25726 In Ref. 25 the probable error is defined as "the numerical value which the true error is as likely to exceed as not", i.e., 50 pct probability. Ref. 26 is even more detailed and includes a lengthy discussion of the applicability of the Gaussian distribution to experimental data. However, the use of the "probable error" has come under some question. For example, Ezekiel'~ states that "the use of the probable error tends to make the results appear rather more accurate than the standard error". Moroney28 stated (in 1951) that "the term 'probable error' was used in former times to denote 0.67450 (50 pct confidence using the normal distribution)....the term, a poor one, is now very much obsolescent. It has been said that 'it is neither an error nor probable' ". Bennett and Franklin in 1954" in discussing statistical confidence levels mentioned that "the customary use of the 5 and 1 pct levels is not completely a matter of chance; these levels probably represent a balance between the desire to be correct and the desire to be specific. Also in most people's minds the borderline between something that could possibly happen and something that is not likely to happen is somewhere in this region. Certainly 5 or 1 pct confidence limits are to be preferred to limits such as the 'probable error' which has only a 50/50 chance of including the correct value." It may readily be seen that the 95 pct confidence level, which is given by 1.960 (assuming large sample size), thus corresponds to approximately three times the "probable error". Indeed, limits of one standard deviation correspond only to about 68 pct probability. Even if we triple the tolerances given by the authors in the equations of their Table 111, the deviations do not become excessive and would not detract from their excellent results. It could then be said with a high degree of confidence (95%) that the precision of the slope and intercept values is about *3-5 percent of their absolute levels rather than the 1-2 percent implied in Table 111. This is then compatible with an earlier suggestion of Gokcen~' of a probable accuracy of 5 pct in dissolved oxygen measurements by the technique employed. Alternatively, the authors could have

Jan 1, 1967

By John M. Lovejoy

FEDERAL regulation of the petroleum resources of the nation has long been an interesting topic for discussion. A plan to accomplish Federal control has now taken definite form. At the request of the President of the United States, a bill to be known as the Petroleum Conservation Act of 1939 has been presented to Congress-H. R. 7372, offered by Representative Wm. P. Cole, Jr., and more usually known as the Cole bill. It is an act ostensibly designed to conserve our petroleum resources, through regulation of production practices. Hearings are being held currently by a subcommittee of the Interstate and Foreign Commerce Committee, in compliance with the request of the President to report the bill early in the next session of Congress.

Jan 1, 1939

By R. D. Reiswig

An increasing amount of high-temperature metall~?~gical research is carried out in resistively heated tube furnaces in which a bare specimen is suspended by a fine wire at the midpoint of the tube. It is shown that the assumption of near-blackbody conditions on the surface of the sample may give rise to errors in optical pyrometry of 50°C or more. A number of papers published in the metallurgical literature in recent years have described the use of high-temperature tube furnaces for heat treatments, melting-point determinations, and other work. Typically, the tube is of a refractory metal with open ends, is heated by the passage of an electric current, and has concentric cylindrical radiation shields outside it. In at least one of these,' the specimen is contained within a crucible having a small hole in its lid through which optical-pyrometer measurements are made under essentially blackbody conditions. In another design,* the specimen is inside a muffle which is concentric with the heater tube and which contains a number of washerlike longitudinal radi- ation shields to reduce axial temperature gradients and to give conditions near the specimen closer to those of a black cavity. Yet another design3 employs a wire specimen coaxial with the heater tube. Blackbody conditions are simulated by passing current from a separate supply through the wire until it "disappears" against the background (the inside of the heater tube) as seen through a radial spy hole in the tube. Good agreement with known melting points is achieved when an optical pyrometer is used under such disappearance conditions as the melting point is approached. That this latter method works so well is due, evidently, to considerations such as those mentioned by Dike4 and others.5-8 A more common method than the above, however, has been the suspension of an uncovered specimen by a fine wire in a resistively heated tube with open ends. A radial spy hole about midway between the ends of the tube permits optical-pyrometer observations on the specimen, the inside of the tube, or both. So observed, the specimen typically appears to differ but little in brightness temperature from the inside of the tube. According to De vos9 the radiation from such a spy hole in an empty tube of reasonable 1ength:diameter ratio (e.g., 10 or greater) should be essentially blackbody radiation. For these reasons, apparently, descriptions of work carried out in such furnaces usually include a statement to the effect that conditions surrounding

Jan 1, 1964

By W. H. Blauvelt

The technical and engineering problems in the manufacture of coke are today the problems of the byproduct oven. Except in a few special localitics, practically no beehive ovens have been built in the United States for the last 5 or 6 years except as renewals of old plants, and during these years the total number of beehive ovens in existence has been steadily falling. On the other hand, the number of byproduct ovens has increased from 4624 in 1911 to a total of about 7660 in operation at the end of 1917; with 2800 building, this makes a total of about 10,460 which will be in operation in 1918, or shortly thereafter. Preliminary Government estimates place the total production of coke for 1917 at 56,600,000 tons, the largest tonnage in the history of the industry. Of this 34,000,000 tons, or 60 per cent., was beehive, and 22,-600,000 tons, or 40 per cent., was byproduct coke. Some time in 1918 the production of byproduct coke should pass the beehive output, and when the byproduct ovens now building are completed the total byproduct capacity will be about 40,000,000 tons of coke per annum, which is over 70 per cent. of the record-breaking total coke production of 1917. The reasons for these changes in the coking industry are familiar to all of us, and need not be discussed here. Improvement in Oven Design Since the byproduct oven was brought to this country from Europe, in 1892, it has been radically improved, and from the point of view of American metallurgical practice it is safe to say that the American ovens arc superior to those of Europe. The points of superiority are mainly those of larger units and larger output per unit, and the greater extent to which labor-saving machinery has been introduced. The increased output is largely due to the use of silica refractory material, which permits higher heats and shorter coking time than are employed in Europe. The modern American oven will carbonize commercially more than 20 tons of coal per day, and contrary to the European idea that slower

Jan 1, 1920

By Wilbert McBride

Two Alco 3 ½ -ton motor trucks were used by Young Bros. while operating at the Mammoth Collins mine at Shultz, Ariz. One was equipped with an oil tank holding 1,075 gal. and was used for the transportation of "tops." The, other was fitted with a stake body and used to carry machinery, wood, rails, pipe and all classes of miscellaneous supplies. The bodies were made of oak with maple flooring and were attached to the frame of the chassis by U-bolts, to avoid drilling the main members of the frame. Most of the hauling was done from Tucson, a distance of 47;2 miles. During the first. 3 months, part of the road was in very bad condition and the tire cost was excessive. After this part was repaired the road was in fair condition, but never good. There were no excessive grades or bad sand, but wagon ruts, too narrow for the truck wheels and of a different gage, caused heavy tire loss; while chuck holes, sharp curves and stones, both imbedded and loose, were objectionable features. During wet weather the trucks could not get sufficient traction to climb some of the hills and were likely to stick in the mud in certain places, so that no attempt was made to run them unless they were on the road when the rain started. This lost time amounted to about 5 per cent. of the total, but, whenever possible, it was utilized in making minor repairs. The price of gasoline, was from 17 to 21 c. per gal. Rubber tires were used throughout. Drivers were paid $4.50 to $5 per shift, and a return trip to Tucson was counted as two shifts even when made in one day. Drivers were provided with a room in Tucson and were paid for all time lost due to causes beyond their control. Trucks were loaded one way only.

Jan 7, 1916

Trans No. Place Date Vol. 1. Wilkes-Barre, Pa. May, '71 1 2. Bethlehem, Pa. Aug., '71 1 3. Troy, N. Nov., '71 1 4. Philadelphia, Pa. Feb., '72.. 1 5. New York, N. Y. May, '72 1 6. Pittsburgh, Pa. Oct., '72 1 7. Boston, Mass. Feb., '73 1 8. Philadelphia, Pa. May, '73 2 9. Easton, Pa. Oct., '73 2 10. New York N. Y. Feb., '74 2 11. St. Louis, Mo. May, '74 3 12. Hazleton, Pa. Oct., '74.. 3 13. New Haven, Conn. Feb., '75 3 14. Dover, N. J. May, '75 4 15. Cleveland, Ohio Oct., '75 4 16. Washington, D. C. Feb., '76 4 17. Philadelphia, Pa. June, '76 5 18. Philadelphia, Pa. Oct., '76 5

Jan 1, 1942

Trans No. Place Date Vol. 1. Wilkes-Barre, Pa. May, '71 1 2. Bethlehem, Pa. Aug., '71 1 3. Troy, N. Nov., '71 1 4. Philadelphia, Pa. Feb., '72.. 1 5. New York, N. Y. May, '72 1 6. Pittsburgh, Pa. Oct., '72 1 7. Boston, Mass. Feb., '73 1 8. Philadelphia, Pa. May, '73 2 9. Easton, Pa. Oct., '73 2 10. New York N. Y. Feb., '74 2 11. St. Louis, Mo. May, '74 3 12. Hazleton, Pa. Oct., '74.. 3 13. New Haven, Conn. Feb., '75 3 14. Dover, N. J. May, '75 4 15. Cleveland, Ohio Oct., '75 4 16. Washington, D. C. Feb., '76 4 17. Philadelphia, Pa. June, '76 5 18. Philadelphia, Pa. Oct., '76 5

Jan 1, 1932

By James T. Kemp

Some interesting and, to American eyes, rather unusual processes for refining impure aluminum derived from scraps were found by American and British investigators who went into Germany in 1945 for the Technical Industrial Intelligence Committee of the Joint Chiefs of Staff. What was found was recorded in a series of reports (see page ), many of which have been released for general reading. This paper gathers under one title and summarizes the German work in refining light metal scrap. Reference must be made to the original reports for greater detail. Basically, the occasion and stimulus for the German developments in treating light metal scrap were hard necessity. Germany needed the metal for a rapacious war industry. Adequate supplies of new aluminum from reduction works were not assured. Great quantities of airplane and other light metal war scraps were forecast. It was evident that the scrap metal would have to be reabsorbed by the producing industry and would have to be kept of good quality. The normal current production of manufacturing scrap was being and could be consumed as generated. It offered no technical problem. The mixed scraps, especially those arising from crashed and decommissioned airplanes, however, presented problems of another kind. Airplane Scrap The recovery of usable aluminum alloy from the mixed assemblies that made up the piles of airplane scrap was attacked in different ways by different groups and with differing degrees of success. Three procedures actually were used on a commercial scale, one was in pilot-plant stage and another had come to a halt in the laboratory a year before Germany collapsed. Four of these five processes actually involved "refining"; that is, some measure of purification of the metal after melting. Sorting and Separation on a Sloping Hearth The simplest procedure for utilizing airplane scrap involved no refining in the strict sense of the word. This was the practice adopted by two representative plants visited by the author, the Leipziger Leichtmetalle Werke, Rackwitz, Saxony, and the Vereinigte Leichtmetalle Werke, Hanover. These firms did essentially the same thing that was done in England but not with equal success, to judge by their shorter experience, the smaller tonnage handled and by the number and quality of alloys produced. The two German firms named rough-sorted scraps by their easily recognizable alloys, essentially by part and shape. They used hand labor to chop and hack and tear apart. The easily separated heavy metal and nonmetallic scraps were discarded as they were found. Steel and the higher-melting-point metal parts riveted to aluminum or built into

Jan 1, 1947

By James T. Kemp

Some interesting and, to American eyes, rather unusual processes for refining impure aluminum derived from scraps were found by American and British investigators who went into Germany in 1945 for the Technical Industrial Intelligence Committee of the Joint Chiefs of Staff. What was found was recorded in a series of reports (see page ), many of which have been released for general reading. This paper gathers under one title and summarizes the German work in refining light metal scrap. Reference must be made to the original reports for greater detail. Basically, the occasion and stimulus for the German developments in treating light metal scrap were hard necessity. Germany needed the metal for a rapacious war industry. Adequate supplies of new aluminum from reduction works were not assured. Great quantities of airplane and other light metal war scraps were forecast. It was evident that the scrap metal would have to be reabsorbed by the producing industry and would have to be kept of good quality. The normal current production of manufacturing scrap was being and could be consumed as generated. It offered no technical problem. The mixed scraps, especially those arising from crashed and decommissioned airplanes, however, presented problems of another kind. Airplane Scrap The recovery of usable aluminum alloy from the mixed assemblies that made up the piles of airplane scrap was attacked in different ways by different groups and with differing degrees of success. Three procedures actually were used on a commercial scale, one was in pilot-plant stage and another had come to a halt in the laboratory a year before Germany collapsed. Four of these five processes actually involved "refining"; that is, some measure of purification of the metal after melting. Sorting and Separation on a Sloping Hearth The simplest procedure for utilizing airplane scrap involved no refining in the strict sense of the word. This was the practice adopted by two representative plants visited by the author, the Leipziger Leichtmetalle Werke, Rackwitz, Saxony, and the Vereinigte Leichtmetalle Werke, Hanover. These firms did essentially the same thing that was done in England but not with equal success, to judge by their shorter experience, the smaller tonnage handled and by the number and quality of alloys produced. The two German firms named rough-sorted scraps by their easily recognizable alloys, essentially by part and shape. They used hand labor to chop and hack and tear apart. The easily separated heavy metal and nonmetallic scraps were discarded as they were found. Steel and the higher-melting-point metal parts riveted to aluminum or built into

Jan 1, 1947

Trans No. Place Date Vol. 1. Wilkes-Barre, Pa. May, '71 1 2. Bethlehem, Pa. Aug., '71 1 3. Troy, N. Nov., '71 1 4. Philadelphia, Pa. Feb., '72.. 1 5. New York, N. Y. May, '72 1 6. Pittsburgh, Pa. Oct., '72 1 7. Boston, Mass. Feb., '73 1 8. Philadelphia, Pa. May, '73 2 9. Easton, Pa. Oct., '73 2 10. New York N. Y. Feb., '74 2 11. St. Louis, Mo. May, '74 3 12. Hazleton, Pa. Oct., '74.. 3 13. New Haven, Conn. Feb., '75 3 14. Dover, N. J. May, '75 4 15. Cleveland, Ohio Oct., '75 4 16. Washington, D. C. Feb., '76 4 17. Philadelphia, Pa. June, '76 5 18. Philadelphia, Pa. Oct., '76 5

Jan 1, 1934

By Cyril Stanley Smith, Earl W. Palmer

FOR several years an investigation has been in progress in the research laboratory of The American Brass Co. to determine the thermal and electrical conductivities of most copper alloys of commercial importance and several of scientific interest. This paper contains such data on the binary alloys of copper with silicon, aluminum, manganese and nickel, and on a large number of ternary or more complex alloys. Some interesting general relationships between the thermal and electrical conductivities for all copper alloys at all temperatures are pointed out. The data for the copper-zinc, copper-phosphorus and copper-tin binary systems have already been publishedl 1,2 † except for the electrical conductivity at 200° C., which is given in the appendix of this paper. LITERATURE ON THERMAL CONDUCTIVITY OF COPPER ALLOYS The papers referred to above contained a summary of the figures available in 1929 for the thermal conductivity of copper alloys. There is given in Table 1 herewith a selection of the data that have appeared since that time. The measurements of Hanson and Rogers3 are particularly interesting since they cover a series of alloys in the alpha solid solution range and show the effect of heat-treatment. Their alloys were tested as annealed castings, and are not therefore directly comparable to the worked alloys measured in the present investigation, although the difference is small. Bailey's determinations4 were carried out on the alloys used by Lees5 in 1906, and extend his results to higher temperatures. It is most unfortunate that the alloys were not analyzed, for the approximate compositions given are hardly sufficient identification of the

Jan 1, 1935

By John Furness Park

The mining district is located in the northeasterly part of Nevada, between the Jarbidge River on the west and the East Fork of the Jarbidge on the east. The northern boundary of the district is but a few miles south of the Idaho state line—the gold-bearing area extending from this point south, for 5 or 6 miles. • The Jarbidge Mountains, in which the ore deposits occur, range from 5000 to 11,000 ft. in elevation, the most important mines being situated about 7000 ft. or higher. The town of Jarbidge lies along the Jarbidge River and is reached by stage from Rogerson, Ida., the nearest railroad point. During the summer months, the camp may be entered from the south by way of Deeth, Nev., but no regular transportation facilities are available over this route. History The mineral deposits were not discovered until 1909, when D. A. Bourne, panning along the river bank, found gold in. the gravel at the mouth of a small stream flowing into the Jarbidge. He prospected in the vicinity of this stream, later known as Bourne Gulch, and shortly after located the North Star claims. During the following spring and summer (1910), the camp of Jarbidge grew from nothing to a town of 2000 people and the hills surrounding it were practically all taken up by mining claims. Most of the work done during the first year or two consisted of trenching and open-cut prospecting. Tunneling was started on a number of claims and many veins were uncovered. Mills were built and operated on a few properties, notably the Pavlak and the North Star. These ran only a few months, however, when they were closed down because of extraction and financial difficulties. A period of development followed in which the majority of the present producing mines were opened. The Elkoro Mines Co. acquired a number of claims in 1915 and started work on the present mill in 1917. Since that time other properties have been taken over until this company is by far the largest operator in the district. Only one other company is now actively engaged in mining, the Bluster Mining & Milling Co., which has

Jan 1, 1925

The Sub-committee on Safety of the Industrial Organization Com-mittee of the Institute has been asked to cooperate with the National Safety Council, and has made certain recommendations to the Board of Directors of the Institute regarding ways and means of bringing about this cooperation. The National Safety Council has been in existence seven years. Its inception was at a meeting of the American Iron and Steel Electrical Engineers held in Milwaukee in 1912. The first annual congress was held in New York City in October, 1913, at which time the Council was definitely organized. Its membership now consists of nearly four thousand members, representing industrial plants, railroads, public utility companies, insurance companies, state labor commissions, Chambers of Commerce, manufacturers' organizations, etc. These members are in all states of the Union and in eleven foreign countries, and through them the National Safety Council reaches more than six million workers.

Jan 7, 1919

By Herbert Hoover

THERE is one problem of the new administration that has received the attention and thought of the organized engineers of America for many years past. This is the problem of the reorganization of the Federal Government. The, inadequacy, the wastefulness, and the inefficiency of our federal organization was evident, enough under pre-war conditions. These inadequacies, these inefficiencies, these wastes were exhibited to the country during the war at the cost of millions. Congress has placed the problem in the hands of a very able Congressional Joint Committee, but if this Joint Committee succeeds in securing the imminently necessary results it will only be by full insistent support to it by public opinion. Many attempts have been made at reorganization before but all, of them have gone to the same crematory-the interminable differences in opinion among the executive and legislative officials over details.

Jan 1, 1921

By AIME AIME

AT the meeting on Engineering Education on Mon- A day afternoon E. A. Holbrook, of the University of Pittsburgh and chairman of the Committee, presided as chairman with W. B. Plank acting as vice- chairman. About sixty members of the educational fraternity were present. Dean Holbrook, after a few introductory remarks, introduced the first speaker of the afternoon, Charles Y. Clayton, who then presented his paper, "Why Do So Few Elect Metallurgy?" in which he stressed the fact that ,one of the things the study of metallurgy ,now needs is publicity and public education on what metallurgy is and 'does. Another thing he brought out is that the study of metallurgy has been looked on for many years merely as a branch of other departments. He gave tables showing past and present enrollment in the course of metallurgy in various schools.

Jan 1, 1930