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By F. G. Tickell, R. C. McCurdy, O. E. Mechem

The behavior of fluids in the voids of a rock is fundamental to the study of many of the problems of oil-field development and production. For it is by virtue of these openings between grains that oil and gas are able to move through the rock, to be contained by the rock, and to pass from the rock into the well. The capacity to contain fluids is measured by the porosity of the rock, and the ease of fluid movement is governed by the permeability. When the engineer wishes to estimate the amounts of oil and gas in an underground reservoir he is often concerned with the porosities of the rocks and, when dealing with problems relating to rate of production, he is more likely to be interested in the permeabilities of the rocks. Rocks are permeable because they are porous, but they may be porous without being permeable. Clays are very porous, and yet they are impermeable from a practical standpoint. Attempts have been made1 to correlate permeability with porosity for certain rock members but, where a definite relationship between these two properties is found to hold, it is purely fortuitous and local. Porosity and permeability do not necessarily bear any quantitative relationship to one another. The porosity of a substance is the percentage of void volume to bulk volume. The petroleum engineer is usually interested only in the inter-granular voids that are accessible to fluids. In measuring porosity he does not wish to include scaled openings. The measurement he desires is one of "available porosity," otherwise called "apparent porosity." The porosity of a natural aggregate of solid grains, such as a sandstone or clay, is governed by: (1) Grain-size distribution, (2) angularity of grain, (3) colloidal content, (4) degree of compaction. It is not difficult, for unconsolidated rocks, to measure the effect of any one of these when it alone is varied, and then to predict what the effects on porosity will be for such single variables. It is very difficult, however, if not

Jan 1, 1933

By R. Steinitz, J. L. Orehotsky

An analysis was made of the influence of floating molten zone traversal on the purification of tungsten rods and the effect of this purification on the brittle -to-ductile transition temperature. The major impurities detectable in the original rods, i.e., molybdenum and oxygen, were reduced by zone refining from 30 to 3 Ppm. Changes in the trace amounts of other impurities could not be quantitatively determined since they were below the limit of detection. Tensile tests on 3-mil wires, drawn from these rods and recrystallized to 17,000 grains per sq mm, showed a transition temperature of 60°C for the zone Purified and 175°C for the original material. 1 HE brittle-to-ductile transition temperature is manifest mainly in the bee metals, iron,' molybdenum, chromium,3 tungsten,4 and niobium. Since many of these metals cannot be fabricated at room temperature in a commercially pure annealed poly-crystalline state, a considerable amount of work has been done on evaluating the influence of purification on the transition temperature in order to determine indirectly whether the fabricability of these metals can be improved by removing impurities. Smith and Rutherford8 showed that the transition temperature of iron is lowered significantly by zone purification. Working with chromium, Edwards, Nish, and wain7 found also that purification appreciably lowered the transition temperature. A similar evaluation has so far not been reported for tungsten, probably because of the difficulties in obtaining tungsten in a purified polycrystalline state. carlson8 and, more recently, schadler9 have purified tungsten rods by floating zone traversal, but after zone traversal, their rods were single crystals. To obtain high-purity polycrystalline tungsten, a technique has to be round for transforming the zone-purified single crystal material into a suitable polycrystalline structure. The purpose of this investigation was to obtain zone-purified tungsten in a suitable polycrystalline state and then to evaluate the effect of zone purification on the transition temperature.

Jan 1, 1962

By John V. Beall

Probably the only hotel in the world with near 100% occupancy at all times is the modern Hotel Indonesia in Djakarta. However, there is little gaiety among the scores of business men who occupy the hotel because they fret as days grow into weeks in seemingly interminable negotiations with government officials. As one man put it, "time is a dimension that they [Indonesians] have never grasped." But the visitors still come in droves to investigate business opportunities in this sprawling nation of tropical islands which is, with 120 million people, the fifth largest nation in the world. Approximately $300 million is being spent each year in Indonesia by foreign companies and governments. Aid grants from the latter are derived about one third from the United States, one third from Japan and the remainder from many nations. Djakarta is a far cry from pleasant colonial Batavia, as the city was called under the Dutch. The orderly colony of prewar days was managed as an agricultural and trading dependency of Holland. The Dutch did little about educating the people. The islands were controlled by the Japanese during World War II and afterwards there was a war for independence--which was attained in 1949. In the ensuing years, President Sukarno devastated the economy by squandering money on a gigantic scale. A Communist-attempted coup in 1965 resulted in a military takeover and the extermination of Communists. The new government under Suharto, which took over all power in March 1966, found itself in a situation where bare survival was the first consideration.

Jan 1, 1970

By EDBIUND U. NORTH

IN making a glass model of mine-workings, each mine will present some little individualities, to meet which will call for the exercise of special ingenuity. Having made several models, I offer the following details of the model of the Montana-Tonopah mine-workings, believing that with small changes for different conditions the method described can be successfully used in making a glass model of the workings of any mine. The model, Fig. 1, has the top, one end, and the front removed. The case is made of kiln-dried pine, painted with several coats of dead-white paint. It is made to take sheets of glass 24 by 42 in. in size, and is 18 in. high, the workings shown being on a scale of 1 in. = 40 ft., or 4800 : 1 scale. The base is made of four pieces of 2-in. material, well pinned and glued together. The back, of material 1 in. thick, is secured rigidly to the base by screws and countersinking. The four posts, 1.5 in. square, are so cut that. the front and two ends of the model fit in flush with the outside edges of the posts. The top rails, 1 in. square, are fastened rigidly to the front and back posts by means of small iron braces. The ends, front, and top of the case are of 0.5-in. material; the ends and front are held in place at the bottom by pegs fitting into the base ; at the top the ends are held by buttons and the front by cupboard-hooks on the inside. Hinged hasps on the cover, fitting over staples in the end-pieces, make it easy to lock the entire case. Before the back is fastened to the base, it is cut with horizontal and vertical grooves to receive the horizontal and vertical sheets of glass, shown clearly in Figs. 1 and 2. The horizontal grooves, spaced to scale, represent the vertical distances between the levels at the shaft. The vertical grooves are placed wherever cross-sections of the workings are desired.

Jan 1, 1910

By E. P. Shea

The Anaconda Co.'s Geological Department at Butte, Mont., was started early in the Company's history because of litigation involving vein ownership and extralateral rights. The problems, some of which were resolved in courts, were many because of the large number of veins and lode locations. Defensive action was required to prove ownership and protect against illegal exploitation of the downward and extra-lateral extensions of the ore bodies. In many cases it was necessary to define the outcrop of the vein and to show that its apex was within the boundaries of the lode claim. Exhibits illustrating geology were needed to present the cases clearly, and these could be made only after careful inspection and mapping of the underground workings by competent geologists. Also, The Anaconda Co. was one of the first companies to recognize the worth of skilled mining geologists and the value of accurate records in the search for new ore. The department was organized in 1900 by H. V. Winchell who, with D. W. Brunton, worked out the methods. Reno Sales was Chief Geologist from 1906 until 1948 when he was succeeded by V. D. Perry, the present Chief Geologist. Under their direction, F. A. Linforth, M. H. Gidel, C. H. Steele, E. P. Shea, C. C. Goddard, Jr., and W. A. O'Brien enlarged the scope of the work and improved the technique.

Jan 3, 1961

By George W. Riter

(Canal zone meeting, November, 1910.) A DISTINGUISHED engineer, the active head of a large mining company, has said that surveying attains the dignity of a profession only in the hands of a few men-the few who know how to keep notes that will be understood by even a novice without further word of explanation. Of all mine-records, survey notes are perhaps the most important. The maps made from them serve as a working-guide, and as framework for other data ; and when, from any cause, access to underground workings is shut off, the surveyor's record often becomes invaluable. So seldom does a surveyor have a chance to check underground surveys by making a closure, that he is compelled to rely on the precision of each step of his work for the accuracy of the final result. When data are fully recorded on the spot, the notes, even in the hands of second parties, become evidence of the care and precision with which the surveying was done. It is worth a great deal to be able to pick up the work of a former surveyor where it was left o$; and to be able to carry it forward without retracing from the beginning. The purpose of this paper is to describe the survey-note system of a mine now under my direction, in which underground surveys had to be relied upon entirely for the proper division of rich ore-bodies between neighbors, thereby placing a premium on accurate surveying and permanent records. In survey-work, it soon turns out that paper is the least item of expense, and that little is gained by trying to economize note-book space. For many purposes it is best to record notes on cards or loose-leaves, which may be left in the office at the end of the day's work, and need not be carried into the mine again, there to become smeared with grime and grease. With the loose-leaf or card system, all notes relating to the same local-

Apr 1, 1911

By Arthur C. Simmons

Oil production and activity in northern and central Pennsylvania was slightly less in 1939 than in the previous year, but owing to higher average prices 1939 was undoubtedly a better business year. The last quarter showed markedly increased activities throughout all of the Pennsylvania fields. Production, Stocks and Price Storage of Pennsylvania crude oil at pipe lines and refineries totaled 5,413,000 bbl. on Dec. 31, 1938, and declined during the year 1,124,000 bbl. to a total of 4,319,000 bbl. at the end of 1939. The stocks of crude at the end of the year represent the lowest point reached in Pennsylvania-grade crude storage in recent years. Stocks increased slightly during April, May and June, but decreased during all other months of 1939. The Bradford field production within the state of Pennsylvania averaged 35,340 bbl. per day throughout 1939, which represents a decrease of 1419 bbl. a day from the 1938 average. The production in central and southern Pennsylvania increased 1176 bbl. per day, averaging 12,159 bbl. throughout 1939. Table 1 includes annual production for the part of Bradford field situated within the state of Pennsylvania, for central and southern Pennsylvania, and for the entire state of Pennsylvania. A definite segregation of production between the Bradford field and central and southern Pennsylvania is slightly ambiguous because a portion of the oil from the newly discovered Music Mountain pool is included statistically in each area. In all probability the entire increase and some small addition to the production from southern Pennsylvania can be attributed to oil produced from the Music Mountain pool. Within the Bradford field, six price changes occurred throughout the year. At the beginning of 1939 the price of Bradford crude oil was $1.80 per barrel, whereas by the end of the year it had risen to $2.50. The weighted average price for Bradford crude during 1939 was $2.059 per barrel.

Jan 1, 1940

By Arthur C. Simmons

Oil production and activity in northern and central Pennsylvania was slightly less in 1939 than in the previous year, but owing to higher average prices 1939 was undoubtedly a better business year. The last quarter showed markedly increased activities throughout all of the Pennsylvania fields. Production, Stocks and Price Storage of Pennsylvania crude oil at pipe lines and refineries totaled 5,413,000 bbl. on Dec. 31, 1938, and declined during the year 1,124,000 bbl. to a total of 4,319,000 bbl. at the end of 1939. The stocks of crude at the end of the year represent the lowest point reached in Pennsylvania-grade crude storage in recent years. Stocks increased slightly during April, May and June, but decreased during all other months of 1939. The Bradford field production within the state of Pennsylvania averaged 35,340 bbl. per day throughout 1939, which represents a decrease of 1419 bbl. a day from the 1938 average. The production in central and southern Pennsylvania increased 1176 bbl. per day, averaging 12,159 bbl. throughout 1939. Table 1 includes annual production for the part of Bradford field situated within the state of Pennsylvania, for central and southern Pennsylvania, and for the entire state of Pennsylvania. A definite segregation of production between the Bradford field and central and southern Pennsylvania is slightly ambiguous because a portion of the oil from the newly discovered Music Mountain pool is included statistically in each area. In all probability the entire increase and some small addition to the production from southern Pennsylvania can be attributed to oil produced from the Music Mountain pool. Within the Bradford field, six price changes occurred throughout the year. At the beginning of 1939 the price of Bradford crude oil was $1.80 per barrel, whereas by the end of the year it had risen to $2.50. The weighted average price for Bradford crude during 1939 was $2.059 per barrel.

Jan 1, 1940

By L. H Levenson, Charles S. Barrett

The orientation of metal crystals and grains, both large and small, can be detcrmined conveniently and accurately without the use of X-ray apparatus. This seems to be appreciated by so few metallurgists that it may be useful to explain in detail the method we have found most satisfactory in the laboratory—the reflection of light from crystallographie etch pits. This note includes a description of a suitable inexpensive instrument and instructions for etching various metals and for plotting the data. As the stereographie projection is used to facilitate handling the data, this note may he considered as an appendix to an earlier review of the metallurgical uses of the stercographie projection.' Various methods involving etch pits have been used by other investigators. Bridgman's method2 consists of attaching the specimen to a sphere (a transparent sphere is convenient4 , holding it at arm's length, and marking a spot on it when it has been turned so that the eteh pits reflect light into the eye of the observer from a lamp standing behind him. It has an accuracy of about 2" and is extrernely rapid. A greater accuracy can be obtained by having the reflected light fall on a screen, as has been done by Czochralski,5 Chalmers,6 and Schubnikov.7 All of these methods have been intended for undeformed single crystals. Tammann and his coworkers3,8 developed a method for estimating the number of grains in a polyerystalline aggregate having orientations in a given region of the stereographic triangle and thus obtained statistical information about deformation and reerystallization textures. While the method has had some use in recent years,9 it is not applicable to the majority of problems in physical metallurgy. Smith and Mehl10 determined orientations by plotting the directions of the sides of individual etch pits on a stereographic projection. The accuracy is limited to about 3" and the method requires careful polishing and high magnification.

Jan 1, 1940

By Charles S. Barrett, L. H. Levenson

The orientation of metal crystals and grains, both large and small, can be detcrmined conveniently and accurately without the use of X-ray apparatus. This seems to be appreciated by so few metallurgists that it may be useful to explain in detail the method we have found most satisfactory in the laboratory—the reflection of light from crystallographie etch pits. This note includes a description of a suitable inexpensive instrument and instructions for etching various metals and for plotting the data. As the stereographie projection is used to facilitate handling the data, this note may he considered as an appendix to an earlier review of the metallurgical uses of the stercographie projection.' Various methods involving etch pits have been used by other investigators. Bridgman's method2 consists of attaching the specimen to a sphere (a transparent sphere is convenient4 , holding it at arm's length, and marking a spot on it when it has been turned so that the eteh pits reflect light into the eye of the observer from a lamp standing behind him. It has an accuracy of about 2" and is extrernely rapid. A greater accuracy can be obtained by having the reflected light fall on a screen, as has been done by Czochralski,5 Chalmers,6 and Schubnikov.7 All of these methods have been intended for undeformed single crystals. Tammann and his coworkers3,8 developed a method for estimating the number of grains in a polyerystalline aggregate having orientations in a given region of the stereographic triangle and thus obtained statistical information about deformation and reerystallization textures. While the method has had some use in recent years,9 it is not applicable to the majority of problems in physical metallurgy. Smith and Mehl10 determined orientations by plotting the directions of the sides of individual etch pits on a stereographic projection. The accuracy is limited to about 3" and the method requires careful polishing and high magnification.

Jan 1, 1940

By COREY C. BRAYTON

PACIFIC COAST steel and iron industries can now take care of all the western and export demands except for heavy structural shapes, thick plates, rails, alloy tool steels, and a few other items. In. 1902 all of our steel came from St. Louis and Milwaukee and points still farther east. A small quantity at that time came from foreign countries. Early mining in the West was, broadly speaking, prior to the steel age. 'Wood for structures and iron for castings were almost exclusively used. Forgings were made of rolled iron that came from the East and foreign countries. San Francisco was, from the early days of mining, the manufacturing center for mining and milling machinery of all types and held that position until the .nineties, when eastern competition began to be felt. Even today in the old mining camps of the West, and many abroad, you will find machines and equipment with familiar San Francisco manufacturers' names. ..Iron, either rolled or cast, entered into their manufacture, for steel castings did not come into general use :until the nineties.

Jan 1, 1929

By Myron K. Rodgers

In rock- or ore-crushing tests all data, in order to be valuable for study and comparison, should be obtained and tabulated under conditions as uniform as possible. The results of many such tests have no value for comparison, because of incomplete data and the lack of uniform conditiops, screens and scale of sizing, etc. The purpose of this paper is to suggest a form of standard specifications which may be developed by the Milling Committee and approved by the A. I. M. E. for rock-crushing tests. It is not intended to discuss any theories of rock crushing. Reports of rock-crushing tests should include the following details: 1. Description of the machine employed (jaw or gyratory crushers, rolls, stamps,tube mills, Chilean mills, etc.), 2. Method and material (timber, concrete, etc.) of foundation. Much power is dissipated in the vibration of poor foundations. 3. Locality from which the rock or ore was obtaincd, and geological, mineralogical, and physical characters of the material. 4. The power consumption of the machine running with no load and with full load, the unit of power being 1 hp. per 24 hr, 5. The capacity of the machine in tons (of 2000 Ib.) per 24 hr. 6. The duty in tons per horsepower-day. 7. The screen analysis of feed and product by the proposed A. I. M. E. standard screen scale. On the foregoing statement, the following remarlrs are offered. Toughness of Rock Table P shows the relative crushing duty of the same machine on three different characters of rock, all other crushing conditions being the same. This table indicates that the specific resistance of the rock to crushing, may affect the crushing duty of a unit of power as much as 300 per cent. Perhaps this quality may be called toughness. It is not a function of hardness only. For comparison of tests, rocks should be divided into

Jan 1, 1916

1. Any society of undergraduates at a technical school, comprising students in any branch of engineering, metallurgy, chemistry, geology, etc, may be recognized by the Board of Directors in its discretion as an Affiliated Student Society, and its name, to¬gether with the names of its president and its secretary, may be published in MINING AND METALLURGY or the DIRECTORY of the Institute. The members of such a society will not be named individually on the membership list of the Institute, but may at any time be proposed for election as associates or junior associates of the Institute, in the usual way. 2. Membership in an Affiliated Student Society, certified by the official representative thereof, and accompanied by suitable testimony as to character and qualifications, will have special weight with the Membership Committee of the Institute, in its consideration of the proposal of a candidate for membership. The Affiliated Student Societies receive the following privileges: 1 A copy of MINING AND METALLURGY free; 2. The use of Employment Service; 3. The use of MINING AND METALLURGY for publicity purposes, such as printing notices of their activities, etc ; 4. Assistance in obtaining speakers for their meetings, lists of moving-picture films, etc. To retain the privileges of the Affiliated Student Society, its officers must keep in touch with the Secretary of the Institute and advise him of its activities. The foregoing plan is not confined to students in mining engi¬neering or metallurgy. Any undergraduate society of engineers may avail itself of the privileges offered. Societies desiring to be recognized as Affiliated Student Societies are requested to make application to the Secretary of the Institute, giving particulars as to their nature, membership and officers. The accompanying list gives the names of the Affiliated Student Societies as of April 15, 1927, and their presidents and secretaries, in so far as they have been reported to the Secretary of the Insti¬tute.

Jan 1, 1923

By H. H. Hausner, S. Storchheim, J. L. Zambrow

The solid state bonding of aluminum to nickel was studied as a function of temperature, pressure, and time at pressure. The initial results indicated that as the reaction conditions were varied, marked changes in tensile strength occurred. Plots of the log penetration coefficient vs the reciprocal of absolute temperature for various isobars were straight lines displaced from each other. THE techniques of bonding different metals to A each other include brazing, welding, welding by application of a molten phase, and solid state welding without any molten phase present. This last technique, the pressing of metals either at room temperature or at some temperature below the melting point of the metals to be joined, seems to offer interesting possibilities for bonding purposes. However, this technique has not been completely investigated, and very little is known about the diffusion phenomena which occur during solid state welding. Some previous work on the effect of pressure on diffusion1 was inconclusive. This paper is concerned with an investigation regarding the effect that the processing variables, such as pressure, temperature, and time at pressure, have in solid state bonding. The tests were made with aluminum and nickel and special emphasis was given to the strength of the bond between these two metals and to the intermetallic penetration rate during the bonding process. It seems that the effect of pressure on the intermetallic penetration is of particular importance for practical purposes and this effect was therefore studied in detail. Procedure Apparatus: The means of solid state bonding used for this study was that of the hot-pressing technique. This method requires the equipment pictured in Fig. 1 and involved the following procedure. The two metals to be bonded were placed in an aquadag lubricated 18-4-1 tool steel die, 16 in. high by 1.440 in. ID, between punches of 1.366 in. diameter made of the same material. A thermocouple

Jan 1, 1955

By C. A. Mitke

(Butte Meeting, August, 1913.) 1. Character of Gases which Caused Helmets to Get Out of Order. DURING September, 1911, the fire area, in the Lowell mine continually increased. and gases resulting from the fire came through the upcast shaft. These gases contained such a large percentage of sulphur dioxide that the men were unable to go up and down on cages, and, within a comparatively short time, repairs in the shaft were found to be necessary. Since the fire was in sulphide ores and extended into certain timbered sections, the gases contained varying amounts of SO2, CO2, and perhaps, at times, CO. The temperature in the shaft was generally about 97°, and the relative humidity from 97 to 99.5 per cent. The corrosive action of the fumes became apparent when the cables had to be changed more often than usual, the heads of lag screws in the guides of the shaft disappeared, and the cages needed frequent repairs. It also became necessary to repair two compartments of the shaft by putting in 150 ft. of new guides between the 600 and 800 levels and lag screws in nearly all the old guides from the surface to the 800 level. 2 Ordinary Methods of Testing Helmets which were Unsatisfactory. These conditions required all work to be done by men wearing oxygen helmets. The Draeger type was tried, and was used until all repairs were completed. At first the helmets were tested for air circulation and air tightness .and the injector was tested by water gauge according to the methods recommended by the Draeger Oxygen Apparatus Co. Six arrangements, covering these different tests, are illustrated in the catalogue and circulars of the company.

Jan 7, 1913

ARTHUR H. STORRS, Scranton, Pa.-I would like to ask whether this same process is applicable to bituminous coal? FELLS A. VOGEL, New York, N. Y.-This Dutch process is applicable to bituminous or any other kind of coal. The Berwind Fuel Co. has had a plant in operation, in Superior, Wis., for about 2 years, using the Dutch process, and it has made a very satisfactory briquette, using Pocahontas coal. There is just one item in Mr. Frey's paper I would like to discuss; that is, the matter of cost. Mr. Frey figures a total cost of $3.35, based on the use of 7 per cent. of oil. Of course, the price of oil has advanced seriously within the last year or two, and any possible reduction in the percentage of oil required in the manufacture of briquettes is very important. I believe that Mr. Frey will agree that very good briquettes can be made with considerably less than 7 per cent. of oil; in fact, actual experience has shown that it can be clone with less than 5 per cent. The only possible effects of a low percentage of oil, particularly in anthracite briquettes, are that the briquette might not burn so freely, and that it might not be quite so hard. Briquettes made by the Lehigh Coal & Navigation Co., using 7 per cent. of binder, are extremely tough. Those briquettes have been handled in one of the local yards in Brooklyn, chuting them from railroad cars into boats and digging them out by grab buckets, and the losses average less than 2 per cent. This compares very favorably with domestic anthracite coal, with which the losses from breakage amount to between 7 and 10 per cent.

Jan 4, 1918

By Thomas A. Wright

No symposium on die casting could be complete without consideration of the methods of formula and impurity control. No consideration of control would be complete without discussion of that new tool of the analytical chemist and inspector, the quartz spectrograph. Just as there is an increased appreciation of the possible applications of the die-casting process and of die castings, so too is there, slowly but surely, of the spectrograph. At present the role of the instrument might well be compared with that of brass or magnesium die castings. Neither is as widely understood or known as they will be. Product specifications are increasing and are getting more explicit and often more rigid. The designer, metallurgist and production engineer or superintendent will be forced to depend more and more on the chemical laboratory. Sampling, as well as analyses, testing and inspection problems will grow. The chemical laboratory must meet its increased responsibility and use of the spectrograph will become more common. Advantages of increased precision, greater speed, lessened labor and often lower costs cannot be ignored. It will be the purpose of this paper in part to outline the respective fields of chemical and spectrographic analyses and to indicate where one may overlap the other and in part to indicate certain possible sources of contamination of zinc-base die-cast alloys in particular. COMPOSITION Aluminum.-Aluminum die castings are expected to conform to the specifications of the American Society for Testing Materials1† and the Society of Automotive Engineers2. The A.S.T.M. has recognized seven

Jan 1, 1935

Arthur H. Elliott, New York, N. Y.: We have all been very much interested in the results of Dr. Bone's work, which Mr. Ellis has presented to us this evening. The high temperatures attained by this method perhaps afford us an explanation of the temperatures reached in the puddling-furnace with its crude and almost primitive methods of burning fuel, by means of which we have, nevertheless, been able to melt iron in a comparatively short time, and keep it in a molten condition down to a high degree of purity. No doubt many of us have wondered, as I have done, how such a result could be obtained in such a way; and it occurs to me that, perhaps, Dr. Bone has supplied the explanation in disclosing the effect on combustion of burning gas and air after passing through, and in contact with, a porous refractory body. May not the fettling of the puddling-furnace have, in some degree, an effect upon the combustion like the influence of the porous diaphragm employed by Dr. Bone ?

Jan 1, 1913

By R. G. Davies

Above 500°C, where dislocation climb is rate controlling, it is observed that the activation energy for creep is independent of the apblied stress, although it varies from 62 kcal per mol at 15 pct A1 to 73 kcals per mol at 20 pctA1 due to the change in short-range ovdw with composition. Below 500°C, when the nonconservative motion of jogs upon dislocations is thought to be rate controlling, the activation energy is stress dependent. A sudden increase in the creep rate, for which no explanation is availab2e, occurs at the highest stress at all temperatures. CREEP has been the subject of numerous research publications during the past decade with most of the attention focused upon high temperature steady state creep, i.e., above 0.5 TM, where TM is the absolute melting temperature, as it is the most amenable to theory. Many of the proposed theories involve the climb of dislocations out of their slip plane, which allows them to circumvent obstacles or to annihilate dislocations of opposite sign on other slip planes.' For pure metals it is observed that the activation energy for this creep is equal to the activation energy for self diffusion.' The position is much more complicated in alloys as there are many possible microcreep mehanisms, as well as dislocation climb, which could be rate controlling. There has been little systematic investi- gation of alloys, but Weertman (lead and indium base alloys)3 and Lawley, Coll, and Cahn (Fe-A1 alloys)4 suggest a microcreep process as the controlling factor. A Cottrell-Jaswon atmosphere mechanism is proposed for the lead and indium alloys, and a mechanism involving crystallographic order for the Fe-A1 alloys. Lawley et al. showed that the formation of a super-lattice, either of the FeAl or Fe3A1 type. decreased the rate and increased the activation energy for creep. From the measurements of lattice parameters,= resistivity,' magnetic properties,7'8 internal friction: and dilatometry10 the ordered region is thought to commence at -19 at. pct Al. However, a recent investigation by the author indicates a value

Jan 1, 1963

A LARGE proportion of the steel that is melted and refined in the United States and poured into ingots is made in basic open- hearth furnaces. The capacity of these furnaces varies over a wide range with a large majority falling within limits of 50 to 200 tons (Fig. 1) The two general types of furnace design used are stationary [ ] and tilting furnaces, the former being much more common. The fuel burned in such furnaces is either one of several types of gas, or a liquid fuel such as oil or tar, or a combination of gas and liquid fuel. GENERAL FEATURES OF FURNACE CONSTRUCTION The design of a modern stationary furnace built to burn liquid fuel and with a capacity of 175 tons is shown in Figs. 2 to 4. The cross- section of the furnace at the tap hole is illustrated in Fig. 2, which shows the bottom construction, sloping back wall, and the rigid steel

Jan 1, 1944