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By P. R. Sperry, A. P. Beck

It has been shown1 that in poly-crystalline strips of high purity aluminum with a fairly random orientation distribution, grain growth progresses gradually until the average grain diameter reaches a value approximately equal to the strip thickness. Recent work at this laboratory led to the realization that grain growth might be impeded to a considerable extent in the presence of a sharply defined texture, where orientation differences between neighboring grains are small. In order to investigate this effect the following experiment was carried out with the same lot of high purity aluminum previously used for grain growth studies in randomly oriented material.' Very large grain size was developed by grain growth at 650°C in specimens of 0.200 in. thickness. These specimens were then rolled to a thickness of 0.050 in. or 1.25 mm—a reduction of 75 pct. In the rolled strip each large grain corresponded to an elongated area easily identified by etching. After annealing for 1 to 25 min at 600°C and re-etching, these elongated areas were again recognizable. Within each area, corresponding to a single large grain before annealing, there formed by recrystallization a multitude of new grains with a fairly well developed preferred orientation. The orientation and the size of the new grains formed in areas corresponding to different large grains, varied widely depending on the orientation of the parent grains with respect to the rolling direction and the plane of rolling. Many areas were found where the average grain size was considerably smaller than the specimen thickness. Such an area occurred in a specimen cut in half before annealing. One half, containing a portion of the area in question, was annealed 1 min at 600°C, the other half, with the remaining portion of this area, for 25 min at the same tempera-Aluminum killed low carbon steel, § which is now used extensively for severe deep drawing or other difficult forming operations, is unusual in that its grain structure, after cold reduction and box annealing in accordance with conventional continuous sheet or strip mill practice, often is elongated, although at times it is equiaxed. Since this unusual structure has been found superior for many, but not all, severe forming operations, recrystallization of the steel, both at constant temperature and on continuous heating, was investigated and compared with that of rimmed steel in the hope that something might be learned about the mechanism of, and the factors controlling, the formation of such elongated grains. In this structure, the grains are elongated both in the lengthwise direction of the strip and transverse to this direction, even though nearly all of the extension in both hot and cold rolling is in the lengthwise direction. The grains are thus roughly pancake-shaped, being longer and wider than they are thick, as observed also by Burns and McCabe,1 and as illustrated by the typical structures shown in Fig 1. Fig la, representing a conventional longitudinal section, shows the length and thickness of the grains, whereas Fig Ib shows their length and width as seen by examining a section parallel to the sheet surface. Both illustrate the very irregular grain boundaries usually associated with the elongated grain shape. A finer equiaxed grain structure in this same grade is shown in Fig Ic. Either the elongated or the equiaxed structure may be present in the annealed product, and in rare instances the two types may coexist in a single specimen, as shown in Fig 1 d. Isothermal Recrystalliza-tion of Rimmed and Alamimum Killed Steel An aluminum killed steel known to have an elongated grain structure after conventional processing (Steel B, Table l), was selected for the initial recrystallization studies; for comparison, a rimmed steel, A in Table 1, was used. Samples of each in the form of hot rolled strip 0.075 and 0.095 in. thick, respectively, were cold rolled on a small laboratory mill in steps of about 0.010 in. per pass to obtain total reductions of 40 and 60 pct. Small pieces of the cold reduced strip were heated in lead at selected constant temperatures for one of several periods of time, then cooled in air. Rate of heating in the lead was, of course, very fast. Hardness of the cooled specimen was measured and a longitudinal section examined metallographically. Isothermal recrystallization curves for these two steels at 1050°F, based on hardness of the air cooled specimens, are shown in Fig 2 in which the amount of recrystallization corresponding to each plotted point is indicated. The marked difference in the behavior of these two types of steel is evident. After a corresponding amount of cold reduction, the rimmed steel recrys-tallizes in a much shorter time than the killed steel and the shape of its recrystallization curve, (plotted on a logarithmic time scale), is very different. The curve for rimmed steel indicates that recrystallization is analogous to isothermal transformation of aus-i.enite in that it proceeds at a progressively faster rate up to some 50 pct recrystallization, then at an increasingly slower rate. For the aluminum killed steel, however, the start of

Jan 1, 1950

By Warfield Garson

Few, if any, of the non-ionizing radiation health hazards to be found in either surface or underground coal mining are uniquely different because of their being found in the work environment. Hence, they can be considered generally for their bio-effects on the worker when found in the mining work environment. The same may not be said, however, for the lack of non-ionizing radiation and its bio-effects, particularly as it relates to underground coal mining. The term "non-ionizing radiation" refers to various forms of electromagnetic radiation of wavelengths longer than those of ionizing radiation. As the wavelength gets longer the energy of electromagnetic radiation decreases. Therefore, all non-ionizing forms of radiation have less energy than cosmic, gamma, and X-radiation. In order of increasing wavelength, non-ionizing radiation includes ultraviolet, visible light, infrared, microwave, and radiofrequency radiations. The energy frequency and wavelength range of both the ionizing and non-ionizing electromagnetic forces are shown in Table I. To convert the wavelengths of various radiations to Ångström units, one multiplies millimicrons by ten. In a vacuum, all electromagnetic radiation has the same velocity, namely 3 x 1010 centimeters per second. The natural source of radiant energy here on earth is our sun which emits radiation continuously over a wide spectrum. This radiation on average reaching earth ranges from 290 nm in the ultraviolet range to over 2,000 nm in the infrared range with a maximum intensity of about 480 nm in the visual range. You will note this falls into the visible blue wavelength and accounts for our blue sky and blue ocean and deep water effects. We are all familiar with the fact that the passage of solar radiation through the atmosphere to the earth changes the spectrum considerably because the atmosphere absorbs and scatters many of the sun's rays. The ozone in the upper atmosphere absorbs the shorter ultraviolet wavelengths and water vapor absorbs some of the infrared wavelengths. Smoke, dust particles, gas molecules and water droplets scatter the rays, especially those of shorter wavelengths. In addition to the sun, every gas, liquid or solid object at a temperature above absolute 0° radiates energy. Solid objects emit almost continuous spectra. At low temperatures only radiation of the longer wavelengths in the infrared range is emitted, but as the temperature of the object is increased, more and more of the shorter wavelengths are added. This fact is most readily demonstrated by heating a piece of steel. When a piece of steel reaches a temperature of about 1,700° Fahrenheit, it gives off radiation at the red end of the visible spectrum and appears dull red. As the temperature is further increased, the shorter rays are also emitted, until at about 2,100°F, the metal appears white, due to the emission of wavelengths throughout the entire visible range. Gasses, on the other hand, when heated emit radiant energy only at certain wavelengths, which are characteristic of their chemical structure. This latter fact is of importance in underground coal mining as high intensity gas and vapor lamps are becoming more and more utilized for illumination in underground coal mining. The biologic effect of non-ionizing radiation exposure depends upon the type and duration of exposure and on the amount of absorption by the miner. The effects of this radiant energy on the miner fall into four distinct types: (1) the heating effect of infrared radiation, (2) the effect on the eye of visible radiation, (3) the effects of ultraviolet radiation, and (4) the growing potential effects of the misuse of microwave radiation. Each non-ionizing type of radiation will be considered individually. ULTRAVIOLET RADIATION The sun is the major source of ultraviolet radiation, which is of concern in open pit and surface mining at certain seasons and in certain climes necessitating protection for the surface miners under those conditions; nonetheless, there are some man-made sources such as electric arc lights, welding arcs, plasma jets, and special ultraviolet bulbs for illumination underground that demand surveillance in the underground environment to be aware of whether the miners are at risk above the threshold limit values allowable. Since ultraviolet radiation has little penetrating power, the organs that are affected are the skin and the eyes. Ultraviolet radiation is strongly absorbed by nucleic acids and proteins, and the effects in man are largely chemical rather than thermal. Short-term effects on miners include acute changes in the skin. These are of four types: (a) darkening of pigment, (b) erythema (sunburn), (c) increase in pigmentation (tanning) and (d) changes in cell growth. Ultraviolet radiation also causes acute effects on the tissues of the eye. Overexposure can lead to keratitis, inflammation of the cornea, and conjunctivitis. Long-term effects of ultraviolet exposure include an increase in the rate of ageing of the skin with degeneration of skin tissue and a decrease in elasticity. Late effects of ultraviolet on the eye include the development of cataracts. The most serious chronic effect of ultraviolet exposure is skin cancer. Ultraviolet radiation effects are increased by some industrial materials and drugs. After exposure to such compounds as cresols, the skin is exceptionally sensitive to ultraviolet radiation. Photosensitivity reactions occur after exposure to a variety of other chemicals and drugs including dyes, phenothiazines, sulfonamides, and sulfanylureas. On the other hand, we must remember that ultraviolet radiation has an important role in the prevention of rickets. Vitamin D is produced by the action of

Jan 1, 1981

By Carroll F. Hardy

The day by day loss of industrial plants to gas and oil is chiefly by default. The coal industry is not selling its superior economy, safety, and other advantages to its customers. THE position of the coal industry has been affected by a wide variety of developments in the production and use of energy. The tempo of development and change has been increasing and the end is not in sight. Legislation is currently being proposed for commercial use of atomic power, and the employment of atomic energy in significant quantity will probably occur about the same time as the decline in production of petroleum and natural gas. But these developments are in the future and have little immediate effect on utilization and marketing of coal. While no one should try to suppress or retard the development of a new and economical source of energy, both the coal and private utility industry should be allowed to question how the nuclear power is to be used, who is to use it, and who is going to pay for it. The taxpayers have a monopoly on fissionable material and the knowledge to employ it. Any commercial use must stem from this source. It is not hard to visualize either taxpayer-subsidized private utility atomic power plants on one hand and super TVA's on the other. In view of the gains of gas and oil in the home heating field, it is interesting to compare the 1940 and 1950 census reports on the kind of fuel used for heating in occupied dwelling units. Table I shows that whereas coal provided 77 pct of the fuel for central heating (furnaces and boilers) in 1940, it was down to 45.4 pct in 1950. However, only about 1 1½ million units were lost in this 10-year period. In the non-central heating category, which principally includes stoves, the percentage declined from 39.2 to 25.6, but the units declined about 2½ million in number. The big increase was in heating units designed to burn gas and oil. Use of wood for central heating declined about one-third. Data on amount of fuels used for residential heating are not available, but information is on hand for residential and comnlercial space heating, see Table 11. Commercial space heating includes office buildings, churches, schools. and similar structures. The annual use of bituminous coal in these two categories declined about 1 million tons in the 10-year period. Other forms of solid fuel showed greater losses, except wood, which remained the same. Domestic stokers reached their high point in 1948 with about 1,200,000 in use. At the end of 1951 there were approximately 1,116,790 stokers in use. Conversions to gas and oil have been from hand-fired heating plants in the ratio of about 7 to 1 compared to stokers. In other words, for every one stoker which has been converted to gas or oil, seven hand-fired units have been converted to gas or oil. A bare recital of these data would indicate that the coal industry is holding its own reasonably well. However, 93.4 pct of the new homes built in 1951 were heated by gas or oil. Oil-burning equipment was installed in 37.8 pct and gas equipment in 55.6 pct of the new homes. This indicates that the public prefers gas when it is available, and that oil is second choice, with all forms of solid fuel apparently used when it is unavoidable. It must be pointed out, however, that during the period of rapid expansion of gas pipelines gas has been sold for house heating at prices that are in some cases actually lower than coal prices, or very nearly on a par. Gas has been sold at wells at far below the comparable price for oil produced from the same wells, and far below its actual worth. This situation is being remedied at the present time by increases in gas prices at the wells. For example, the wellhead price of gas in Texas averaged 7.494 per Mcf in 1952. In 1949 it was 4.59c per Mcf. This increase in price is being reflected in pipeline gas prices, and in most of the markets served by the pipelines the tendency is to get it out of the bargain basement type of sales. The American Gas Association estimates that at the end of 1952 there were in the United States about 11 million customers for gas house-heating, and the Association expects additional gains each year until around 18 million homes will be heated by gas in 1975. By 1975 there should be 60 million dwelling units to be heated in the United States, if dwelling units increase at the same rate as the population. If the gas industry heats 18 million dwelling units by that time, this still leaves 42 million units to be heated by some other fuel. If oil is used to heat 18 million dwelling units in that same year, 24 million would of necessity be heated by coal, coke, wood, electricity, or another fuel. The total number of dwelling units using coal listed in the 1950 Census was 18,776,000, so it would appear that coal has a chance at least to stand still in the tonnage sold for domestic use. In the first quarter of 1953, 2044 domestic stokers

Jan 1, 1955

By R. C. J. Goode, W. S. Rapson, W. R. Lawrie, L. W. P. Van Der Bosch

W. R. Lawrie (Member): As all the Institute members present are aware, the Ninth Commonwealth Mining and Metallurgical Congress was held in Great Britain from 3rd to 24th May, 1969. The Congress opened in London and the first week was devoted to technical sessions. Several receptions and other forms of entertainment were held in the evenings. The Congress was attended by some 1 200 delegates, many of whom were accompanied by their wives. As can be imagined a large organisation was needed to cater for all the whims of these delegates, to arrange accommodation and to provide transport for the technical trips, for the receptions and for the sight-seeing tours. Papers presented at the technical sessions proved of great interest. It was stimulating to hear of the developments taking place in the various branches of mining and metallurgy. The discussions which developed between men from so many different countries were thought provoking, led to new friendships and most of us made valuable contacts for the future. There were 141 papers presented in the one week. They were given in four separate halls with two, three and sometimes four papers coming up for discussion in each of the three sessions per day in each hall. Among the more interesting subjects were those concerning off-shore drilling and the facilities for production of petroleum and natural gas. Beach mining at Consolidated Diamond Mines drew a large audience. Automation, mechanization and other technical developments were well described and we were brought up to date with modern techniques of mineral prospecting. There was general discussion on the future of the mineral industries together with comments on the consumption and price trends of these metals and minerals. The future of uranium, of vital interest to us in South Africa, came in for much debate. During the first week, besides attending the technical sessions and seeing some of the sights of London, we were royally entertained. There was a banquet, attended by some I 400 people, where we were welcomed by Princess Alexandra, a reception by H.M. Government in the Banqueting House, and we were entertained at the House of Lords on a terrace overlooking the bustling and rather muddy river Thames. Then there was the visit to the Glyndebourne Opera. It is only in London that at 3 o'clock of an afternoon, nearly 1 000 people all togged up in dress suits and long dresses and carrying packets of sandwiches for supper could arrive at a station to catch a train, and not even cause a stir of interest or a raised eyebrow! This is the way we travelled 60 miles to the opera from London. Surely there can be no more picturesque or romantic a setting for an opera than this large 400-year old red brick manor house nestling in the green valleys of the unspoilt Sussex countryside. It was a glorious evening and though we returned somewhat late and tired, not one of us would have missed this experience. After the first week in London there was a choice of tours of one week to London and the Home Counties, Cornwall, a Geological tour to Scotland, South Wales, and North England. These were followed by further one week tours to Yorkshire and Lancashire, Scotland, West Country and Midlands, a Geological tour of Wales, and a Mining and Geological tour to Jurassic Iron Mines. We then returned to London for the final session and closing banquet. Post-congress tours were arranged to Europe and to Ireland. It was a wonderful Congress, a great experience, we made many friends and may there be many more congresses! . L. W. P. van den Bosch (Member): Much has already been said in appreciation of the excellent organisation and arrangements made for the delegates who attended this Congress. This report is confined to a brief discussion of the personal impressions gained from the papers presented and the technical visits attended. The papers covered a wide variety of subjects ranging from highly theoretical observations to practical descriptions of operations. There were three main themes, VIZ: 1. The attention given to research and its forceful application to practical operation. 2. A steady development in mechanization and automation leading to savings in manpower. 3. Improvization, modernization and adaptation of exisitng facilities. Thoughts on these themes can best be illustrated by comments on some of the industries visited. COAL The National Coal Board (N.C.B.) has been most progressive and all of us have heard of the Bevercotes Colliery with its completely automatic mining and coal handling equipment. This was not, unfortunately, on show but there is no doubt that this is one of the greatest advances in coal mining leading towards continuous production. Coal in Britain is fighting for its life against oil, North Sea gas, imported gases and nuclear power. Output is dropping, the less efficient collieries are closing down and efficiencies are steadily rising as the following tabulation indicates: In 1931: 1 million men produced 300 million tons of coal In 1947: 0.7 million men produced 230 million tons of coal In 1968: 0.4 million men produced 160 million tons of coal

By Robert W. Miller

There are many problems faced by ventilation engineers in deep underground mining operations, not the least of which is controlling miner exposure to radon gas and its daughter products. Radon gas is commonly found in uranium mining operations, but may also be present in other deep metal mines. For example, tin mines in England, iron ore mines in Sweden, gold mines in South Africa, and molybdenum mines in the U. S. have potential radon exposures. This is because uranium and accompanying radium ore are ubiquitous to the earth's crust albeit at low levels. The fact that the activity represented by one WL can be caused by a relatively low concentration of radon gas increases the difficulty of control. Since the source of the radon gas is usually widespread throughout a mine, local exhaust ventilation is not a viable control schema. The technique used to control exposure is then dilution ventilation and, in fact, huge amounts of air must be moved in order to reduce potential exposures to an acceptable level. An interesting comparison can be made of ventilation rates in different types of mines. It is estimated in modern coal mines, which are generally acknowledged to have high rates of ventilation, that about eleven tons of air are moved for each ton of ore mined. A typical operating uranium mine may have ventilation flows of 14-15 tons per ton of ore mined. This provides an idea of the scope and importance of ventilation in modern mining operations where radon is a hazard. Further pressure is put on ventilation engineers by the steady downward trend in exposure limits set by national and international standard setting agencies. Much of this tendency toward lowered standards is based upon longitudinal mortality studies of miner populations. Another important factor is the limited number of experienced miners available in the labor pool. For optimum production, it is important to have as many experienced miners underground in each shift as possible. However, the average daily exposure in a U. S. mine must be less than .3 WL to permit the miner to work underground for a full year. The ventilation system then must provide enough uncontaminated air to maintain the WL below the .3 TTL level to maximize production efficiency and minimize personnel turnover and the problems associated with it. Ultimately, the goal of the ventilation engineer and health physicist is to protect the working miner from harmful exposures based upon currently acceptable standards. U. S. Federal regulations require that in uranium mines all active work sites must be monitored every two weeks if they measure above .1 WL. Areas that have .3 WL ratios or higher must be monitored on a weekly basis until five consecutive weekly samples show the level has dropped below .3 WL. Also, exposure records must be kept for all individuals exposed to levels exceeding .3 WL. These requirements provide a strong economic incentive to have a ventilation system that minimizes exposure of any personnel. A good ventilation system requires careful planning, operation and backup in order to fulfill its mission of providing adequate clean air. Its proper operation also requires coordination with production personnel so it can be adapted as new areas in the mine open up and old areas are sealed off. The ultimate indicator of ventilation efficiency to control radon daughter exposure is, of course, monitoring working levels. Historically, this has been done using the Kusnetz, Tsivoglou, and Rolle's methods, among others. These methods all require cumbersome equipment and tedious calculations to obtain the measurements that results in WL. More important, however, they require a significant time lag between sampling and counting, typically 40-90 minutes. This time lag is, in fact, what can cause significant economic losses due to unnecessary downtime as well as high WL exposures. In a typical mining situation, a sampling technician using the Kusnetz method takes a sample, moves to the next location and takes another sample and so on. Forty to ninety minutes after the first sample, the technician will stop, run the activity count on the filter and calculate the WL. The technician may be one-half mile away or several levels removed from where the first sample was taken when it is counted. If the WL ratio is high the technician must then backtrack to the sample position. There are then two options. If the sample area is a working stage, it can be shut down or a second sample can be taken. If the first alternative is chosen; i.e., shutdown and correction of the ventilation, then another sample must be taken, followed by a forty minute wait for results. If the ventilation adjustment didn't correct the problem, then the whole process must be repeated with a minimum of forty-five minutes per sample cycle when using the Kusnetz method. It has been estimated from operating uranium mines that the cost per hour for downtime on a production slope is about $1,50O/hour. The time lag between sampling and resultant data can be very costly. If the second alternative is chosen to verify the first reading, the miners may be unnecessarily exposed to high levels while waiting for the result. Clearly, such a sampling system can be markedly improved by eliminating the excessive time lag between sampling and analysis.

Jan 1, 1981

By Paul L. Horrer

Costly damage by severe wave attack to many engineering structures has illustrated the need for a consideration of the nature of wave action in plans for offshore drilling operations. Using wave data it is possible to answer questions pertaining to engineering problems such as platform elevation, structure orientation, and expected wave forces. For locations where wave records are not available a technique can be used to obtain information about wave characteristics from past meteorological data and near shore submarine topography. Forces exerted on structures by waves may be divided into four parts. A completed study is given in which frequencies of various wave heights and maximum frictional drag forces are computed for a typical offshore drilling site. INTRODUCTION Waves of tremendous proportions accompanying hurricane winds crash against breakwaters and other offshore structures causing untold damages. Wave forces exerted on structures at these times are enormous, as shown by past records of incidents where massive portions of breakwaters have been broken off and moved by waves. On other similar occasions, whole structure; have been unloosed and smashed or floated away. These incidents, which seem almost incredible, serve to illustrate the great amount of energy contained in large waves, and to show that this energy results in powerful forces destructive to offshore installation~ which are not designed sufficiently strong to withstand wave attack. In the past the expected frequencies of waves having various characteristic.% have rarely been considered in the design of structure affected by wave action. As a result, many structures have failed to accomplish the purpose for which they were designed or have collapsed under wave attack. Others have been constructed to withstand greater wave energy than is ever encountered, with resulting waste of material and construction time. In this study an analysis is made of the frequencies of waves having different characteristics which affect the plans for offshore drilling installations. After such an analysis the erection of these structures can proceed with less risk involved and with more efficiency and economy. ENGINEERING ASPECTS In the offshore drilling program wave forces play an extremely important part in design and construction of drilling rigs in shallow water. The design of a platform or other structure from which drilling equipment is operated is critical, becauze any damage to the platform may endanger personnel and result in complete loss of equipment. Since a platform built too close to the water would be battered by breakers, and one built unnecessarily high would involve undue expense, it is necessary to know the most desirable elevation at which the platform should be erected. This is only one of many questions about structural planning which can be answered using existing technique for determining wave characteristics. The purpose of efficient design for the portions of many types of offshore structures which are acted upon by wave forces is the same as that of all designs which deal with frictional forces of a fluid on a solid. For these structures the problem is comparable to that encountered by undersea craft moving through water, except that in the case of a fixed structure the force is produced by the water moving past the model. For off shore sructures which are extremely rigid the frictional forces may be nearly negligible compared with the impact or shock forces imparted by breaking waves. In all case; the better design is that which offers the least resistance to the opposing forces. From a consideration of wave forces, each drilling structure varies in efficiency depending upon the type and amount of superstructure in contact with the waves. For example, round piling and bracing offer less resistance to wave forces than do I-shaped ones. All network superstructure such as cross bracing should be kept to a minimum and at as low an elevation as possible, so that it will not expecience the pressure exerted at the tops of breaking waves. Models of proposed structures can be tested in wave tanks and in the field to ascertain the efficiency of specific designs. Past experience in beach and shoreline engineering has shown that, although changes in the topography of the bottom very near shore do not seem to be occurring, the natural forces involved may be in a delicate balance such that a static state exists. Interruptions of any of these natural forces by erecting offshore structures are likely to cause undesirable effects. Changes in beach profile result partly from sediment being brought into suspension by the orbital motion of waves and partly from the transport of sediment by longshore currents. With the erection of an offshore structure and consequent change in the combined effects of these two forces, unfavorable deposition upon, or erosion of, the bottom at the site may occur. Therefore, combination wave and current studies are essential for the solution of problems involved in the design of most marine structures. TECHNIQUE FOR OBTAINING WAVE INFORMATION In determining the probable effect of wave action on an offshore drilling structure, it is first necessary to know the usual frequencies of certain wave types for the given location. A technique has been developed which provides a means for obtaining information about wave characteristics in the

Jan 1, 1949

By Paul L. Horrer

Costly damage by severe wave attack to many engineering structures has illustrated the need for a consideration of the nature of wave action in plans for offshore drilling operations. Using wave data it is possible to answer questions pertaining to engineering problems such as platform elevation, structure orientation, and expected wave forces. For locations where wave records are not available a technique can be used to obtain information about wave characteristics from past meteorological data and near shore submarine topography. Forces exerted on structures by waves may be divided into four parts. A completed study is given in which frequencies of various wave heights and maximum frictional drag forces are computed for a typical offshore drilling site. INTRODUCTION Waves of tremendous proportions accompanying hurricane winds crash against breakwaters and other offshore structures causing untold damages. Wave forces exerted on structures at these times are enormous, as shown by past records of incidents where massive portions of breakwaters have been broken off and moved by waves. On other similar occasions, whole structure; have been unloosed and smashed or floated away. These incidents, which seem almost incredible, serve to illustrate the great amount of energy contained in large waves, and to show that this energy results in powerful forces destructive to offshore installation~ which are not designed sufficiently strong to withstand wave attack. In the past the expected frequencies of waves having various characteristic.% have rarely been considered in the design of structure affected by wave action. As a result, many structures have failed to accomplish the purpose for which they were designed or have collapsed under wave attack. Others have been constructed to withstand greater wave energy than is ever encountered, with resulting waste of material and construction time. In this study an analysis is made of the frequencies of waves having different characteristics which affect the plans for offshore drilling installations. After such an analysis the erection of these structures can proceed with less risk involved and with more efficiency and economy. ENGINEERING ASPECTS In the offshore drilling program wave forces play an extremely important part in design and construction of drilling rigs in shallow water. The design of a platform or other structure from which drilling equipment is operated is critical, becauze any damage to the platform may endanger personnel and result in complete loss of equipment. Since a platform built too close to the water would be battered by breakers, and one built unnecessarily high would involve undue expense, it is necessary to know the most desirable elevation at which the platform should be erected. This is only one of many questions about structural planning which can be answered using existing technique for determining wave characteristics. The purpose of efficient design for the portions of many types of offshore structures which are acted upon by wave forces is the same as that of all designs which deal with frictional forces of a fluid on a solid. For these structures the problem is comparable to that encountered by undersea craft moving through water, except that in the case of a fixed structure the force is produced by the water moving past the model. For off shore sructures which are extremely rigid the frictional forces may be nearly negligible compared with the impact or shock forces imparted by breaking waves. In all case; the better design is that which offers the least resistance to the opposing forces. From a consideration of wave forces, each drilling structure varies in efficiency depending upon the type and amount of superstructure in contact with the waves. For example, round piling and bracing offer less resistance to wave forces than do I-shaped ones. All network superstructure such as cross bracing should be kept to a minimum and at as low an elevation as possible, so that it will not expecience the pressure exerted at the tops of breaking waves. Models of proposed structures can be tested in wave tanks and in the field to ascertain the efficiency of specific designs. Past experience in beach and shoreline engineering has shown that, although changes in the topography of the bottom very near shore do not seem to be occurring, the natural forces involved may be in a delicate balance such that a static state exists. Interruptions of any of these natural forces by erecting offshore structures are likely to cause undesirable effects. Changes in beach profile result partly from sediment being brought into suspension by the orbital motion of waves and partly from the transport of sediment by longshore currents. With the erection of an offshore structure and consequent change in the combined effects of these two forces, unfavorable deposition upon, or erosion of, the bottom at the site may occur. Therefore, combination wave and current studies are essential for the solution of problems involved in the design of most marine structures. TECHNIQUE FOR OBTAINING WAVE INFORMATION In determining the probable effect of wave action on an offshore drilling structure, it is first necessary to know the usual frequencies of certain wave types for the given location. A technique has been developed which provides a means for obtaining information about wave characteristics in the

Jan 1, 1949

The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal. STANDARDS FOR ACCEPTANCE To merit consideration papers should be of sufficient high standard and contain matter that is new, interpretations that are novel or of new significance and conclusions that cast a fresh light on old ideas. Their publication should be of real interest to technical men and of benefit to mining and industry. Authors must realize that because a mine shaft is new or the mine itself is newly established, this in itself does not justify a paper unless significantly new techniques or processes were involved in the opening-up procedure. A few well selected diagrams and illustrations are often more pertinent than an amorphous mass of less well chosen material. Over-statement and dogmatism are jarring and have no place in technical writing. The amount of textbook material included in a contribution should be the minimum essential to the argument. The length of a paper is not the criterion of its worth and it should be as brief and concise as possible, consistent with the lucid presentation of the subject. Avoid the use of the first person, be objective and do not include irrelevant or extraneous matter. Papers should be submitted at least three months prior to the intended date of presentation. The text should be typewritten, double-spaced, on one side only of foolscap paper, leaving a left-hand margin of 11-inches, and should be submitted in duplicate to facilitate the work of the referees and editors. Galley proofs are sent to the authors for the correction of printers' errors and not for the purpose of making alterations and additions which may be expensive. Should an author make alterations which are considered excessive, he may be required to pay for them. ORTHODOX SEQUENCE Title and author's name together with author's degrees, titles and position Summary, abstract or synopsis Introduction Development of the main substance Conclusions References. Title: This should be as brief as possible, yet give a good idea of the subject and character of the paper. Style: Writing should conform to certain prescribed standards. The Institute is guided in its requirements by: Collins, F. H. Authors' & Printers' Dictionary-Oxford University Press. Hart, H. Rulesfor Compositors and Readers. Humphrey Milford (familiarily known as the Oxford Rules). Fowler, H. W. & F. G. The King's English-Oxford University Press. Generally: Avoid unnecessary use of capitals and hyphens, while punctuation should be used sparingly and be governed by the needs of sense and diction. Sentences should be short, uninvolved and unamiguous. Paragraphs should also be short and serve to separate basic ideas into compact groups. Quotation marks should be of the 'single' type for quotations and "double" for quoted matter within quotations. Interpretations in the text should be marked off by parenthesis ( ), whereas brackets [ ] are employed to enclose explanatory matter in the text. Words to be printed in italics should be underlined singly. For small capitals they are to be underlined DOUBLY and for large capitals TREBLY. Abbreviations and symbols are laid down in British Standard 1991 and proof correction symbols in British Standard 1219C. Abbreviations are the same for the singular and plural, e.g. ft for foot and feet, lb for pound and pounds. Percentages are written in the text as per cent; the symbol % is restricted to tables. Likewise ft and in. should be used, x' y" only being permissible in diagrams and plans. Drawings and diagrams are to be in black India ink and should be about 6 in. wide. 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By H. W. Meyer, H. N. Lander, F. D. Delve

A method of calculating the changes in blast-furnace performance brought about by burden and/or blast modifications is presented. Essentially the method consists of three simultaneous equutions derived from materials and heat balances. These equations can be used not only to evaluate quantitatively the effect of changes in process operating variables on furnace performance, but also to provide a useful means of evaluating changes in process variables which cannot be measured directly. It has been customary for a number of years to use simple heat and materials balances as a basis for assessing blast-furnace practice. A good example of the method used to set up these balances is that proposed by Joseph and Neustatter.1 This approach to process assessment has limited utility, however, in that it cannot be used to predict the furnace coke rate or production under new operating conditions. Using an approach based on multiple correlation of blast-furnace variables, R V. Flint2 has developed an equation which may be used to predict the change in coke rate that will result from some changes in operating conditions with a reasonable degree of accuracy. Although this equation has useful applications in production planning, it cannot be used to study the relationships between the operating variables and the fundamental thermochemi-cal characteristics of the process. In attempting to analyze the blast-furnace process quantitatively, the idea of dividing the furnace into zones3 may at first appear attractive. In our present state of knowledge, however, it is not possible to define with any accuracy the physical limits of such zones in relationship to their temperatures or to the reactions which may occur in them. Although its application is restricted, the zonal approach to blast-furnace analysis is useful in some instances. For example, the change in the calculated flame temperature in the "combustion zone" caused by injecting steam constitutes information which is helpful in understanding why the addition of steam to the blast is best accompanied by an increase in blast temperature. The zonal approach cannot, at the present time, be used to establish the relationships between process variables and process performance if the whole process rather than part of it is to be considered. One of the earliest approaches to the problem of relating blast-furnace operating variables to pro- duction and coke rate was that developed by Marshall.4 Essentially Marshall's work showed that it was possible to estimate the performance of a furnace by solving three simultaneous equations which consisted of rudimentary carbon and heat balances plus a further equation relating the production, wind rate, and the carbon burned at the tuyeres. Although these equations did not include all of the chemical and thermal variables of the process, their derivation and application seems to be the earliest attempt which achieved any success in relating prior furnace operating data to the calculation of furnace performance under different blast conditions. Work carried out in Germany has been directed mainly towards prediction of coke rates using material and thermal balances rather than statistical methods. wesemann5 used prior furnace operating data as part of the basis for predicting the change in coke rate accompanying a change in burden composition. This author employed a method of successive approximations to estimate the secondary changes in slag volume and stone rate brought about by the change in coke rate. The most recent analysis, which seems to have been developed concurrently with the thermochemical model presented in this paper, has been described by Georgen.6 This author has succeeded in improving on Wesemann's approach by expressing the total changes in the slag volume and stone rate in terms of the change in coke rate itself. This is accomplished in a manner similar to that used in the thermochemical model described in this paper. Although Georgen makes use of a calculated furnace heat loss, he does not relate the heat loss per unit of hot metal to the production rate as is done in the present work. Georgen's approach may be used to calculate the changes in materials requirements accompanying changes in furnace operation; it cannot be used to assess the resulting changes in production. The fact that blast-furnace behavior can be interpreted by consideration of the heat requirements of the process was demonstrated by Dancy, Sadler, and Lander.7 In the analysis of blast-furnace operation with oxygen and steam injection these authors showed that it was possible to account for the changes in production and coke rate

Jan 1, 1962

By Gregory R. Wessel

Sulfur is a nonmetallic element widely distributed in nature and of great physical and economic importance. It is the 14th most abundant element in the Earth's crust (0.06%) and an important constituent of animal and plant life. Sulfur has been known and used since ancient times for a number of medicinal and industrial uses. At present, most sulfur is used to generate sulfuric acid that is used in a wide variety of industrial processes, particularly the production of fertilizer. Because of this, sulfuric acid (and hence sulfur) consumption is often regarded as a good index of a nation's industrial development. In the past, sulfur was mined from surface occurrences in several geologic environments, and was used in relatively small amounts. With time, the uses of sulfur and sulfuric acid expanded, as has the need for larger quantities of these commodities. Sulfur is now mined from both surface and underground deposits, and is recovered as a byproduct from a number of industrial processes. Despite valiant efforts and years of work by sulfur explorationists and others, many aspects of sulfur mineralization remain controversial. Almost as controversial is the spelling of the word sulfur. The English spelling sulphur commonly is used outside America and in the American sulfur mining industry, but sulfur is the correct American spelling as approved by the American Chemical Society, the American Geological Institute, and many others. Those new to the American sulfur industry often find it puzzling to be reprimanded for using the correct American spelling. Sulfur resources are abundant and widespread, but the extent to which they can be classified as reserves is constrained by pre- vailing prices and extraction technologies. At present, sulfur can be economically mined from very few deposits. The sulfur industry is roughly divisible into two sectors: voluntary (or discretionary) and involuntary (or nondiscretionary). In voluntary production, the mining of sulfur or pyrites is the sole objective, and the recovery of the resource is as complete as economic conditions will allow. During involuntary production, sulfur or sulfuric acid (termed recovered sulfur) are produced as byproducts, and the quantity of the output is dictated by the demand for the primary product. Voluntary sulfur now accounts for only about 35% of the elemental sulfur produced worldwide, and most inves- tigators believe that voluntary sulfur will be less important in the future. Sulfur sources and products are described as follows (after Barker, 1983): Sulfur Sources: Combined sulfur-sulfur that occurs in nature combined with other elements, commonly referring to sulfides and sulfates. Cupriferous pyrites-pyrite containing minor amounts of cop- per sulfides. Hydrogen sulfide-a toxic gas that occurs in petroleum and natural gas. Involuntary sulfur-sulfur produced as a byproduct in response to legislative or process mandates. Native sulfur-naturally occurring elemental sulfur. Nonferrous metal sulfides-opper, lead, zinc, nickel, and molybdenum sulfides that are processed for their metal content. Organic sulfur complex organic sulfur compounds that occur in petroleum, coal, oil shale, and tar sands. Pyrites-iron sulfide minerals that include pyrite, marcasite, and pyrrhotite. Sulfate sulfur-sulfur contained in anhydrite and gypsum. Voluntary sulfur-sulfur produced in response to market demand. Basic Sulfur Products: Acid sludge-contaminated sulfuric acid usually returned to acid plants for reconstitution. Brimstone-synonymous with crude sulfur. Bright sulfur-crude sulfur free of discoloring impurities and bright yellow in color. Broken sulfur-solid crude sulfur crushed to -8 in. Byproduct sulfuric acid-sulfuric acid produced as a byproduct of a metallurgical or industrial process, generally relating to combined sulfur sources. Crude sulfur-commercial nomenclature for elemental sulfur. Dark sulfur-crude sulfur discolored by minor quantities of hydrocarbons, ranging up to 0.3% carbon content. Elemental sulfur-processed sulfur in the elemental form produced from native sulfur or combined sulfur sources, generally with a minimum sulfur content of 99.5%. Formed sulfur-elemental sulfur cast or pressed into particular shapes to enhance handling and to suppress dust generation and moisture retention. Frasch sulfur-elemental sulfur produced from native sulfur sources by the Frasch mining process. Liquid sulfur-synonymous with molten sulfur. Liquid sulfur dioxide-purified sulfur dioxide compressed to the liquid phase. Molten sulfur-crude sulfur in the molten state. Prilled sulfur-solid crude sulfur in the form of pellets produced by cooling molten sulfur in air or water. Recovered sulfur-elemental sulfur produced from combined sulfur sources (including byproduct hydrogen sulfide, but sometimes referring only to sulfur from fossil fuels) by any method. Slated sulfur-solid crude sulfur in the form of slate-like lumps, produced by allowing molten sulfur to solidify on a moving belt. Specialty sulfur-prepared or refined grades of elemental sulfur that include amorphous, colloidal, flowers, precipitated, wettable, flour, and paste sulfur. Sulfur ore-unprocessed ore containing native sulfur.

Jan 1, 1994

By K. G. Wikle, J. G. Klein, W. W. Beaver

Consolidation of hydride process, electrolytic, calcium reduced, and comminuted thorium powder, as well as saw chips and lathe turnings, by vacuum hot pressing and by cold pressing-vacuum sintering was studied. The mechanical properties of the consolidated material in the extruded form are compared with those of wrought castings. AT present there little little industrial use for thorium metal, although it has some important though small scale applications in electronic equipment. Despite its high inelting point—about 1750°C —a low modulus of elasticity, 11.4xl0 si at 20°C;' relatively low mechanical properties coupled with a high density, 11.7 g per cu cm; and an unusually high chemical activity with normal atmospheres limit any structural applications. The metal is utilized as an alloying element principally in magnesium. Pure thorium finds utility as electrodes in gaseous discharge lamps such as the high intensity mercury lamp' because its low work function and high electron emissivity provide lower starting potentials and more uniform operating characteristics than other available materials. The metal is also found in photoelectric tubes used for the measurement of the ultraviolet spectrum." Thorium metal has been used in germicidal lamps of the cold cathode type as sputtered coatings on nickel in order to provide a low work function surface and a low starting voltage. Other applications have involved the radioactive properties of thorium for the production of ionized particles." The potential value of thorium is much greater than its present use pattern because of possible utility in the field of nuclear power. Th may be converted through nuclear reaction to a fissionable element U which should be capable of acting similarly to U in the g'eneration of atomic power. Thorium has been reported to be about three times as plentiful as uranium in the earth's crust, placing it in the order of abundance of lead and molybdenum." Thus, it is of interest in augmenting the potential supply of fissionable material for nuclear power. Because of its high melting point, thorium is usually produced as a powder through the calcium reduction of its oxide or thermal reduction of halides by sodium, magnesium, and calcium. It may also be produced in flake form by electrolysis of fused alkali or alkaline earth chloricles and fluorides. Therefore, powder metallurgy assumes importance in the fab- rication of thorium metal shapes. Furthermore, it is rather difficult to obtain pure thorium by melting, as the molten metal reacts readily with graphite as well as oxide, carbide, and nitride refractories. These contaminate the melt with oxides, carbides, and metallic impurities." The current investigation was undertaken to examine the fabrication of thorium by powder metallurgy methods which have been used for the commercial production of beryllium and other metals.' A sparcity of data concerning the comparative cold and hot compaction of thorium powders of different derivation existed. Therefore, all commercially available types were examined along with other experimentally produced thorium powders in order to round out the comparison of consolidated thorium powders with melted reguline metal. Review of the Literature By heating a mixture of ThC1, with potassium, Berzelius made the first thorium metal as an impure powder in 1828. Improvements in the basic process, increasing thorium assay to 99 pct, were made by several investigators including Arsem," Lely and Hamberger10 and Von Bolton." Calcium reduction of Tho, to make powders was investigated by Berger," Huppertz,'" Kroll," and Kuzel and Wedekind.'" A thorium powder produced by this method using a CaC1, fluxing agent assayed 99.7 pct, as reported by Marden and Rentschler.'" Compacted and sintered, this product was found to be ductile, and could be fabricated into wire and sheet. Improvements of the calcium reduction process were made later" wherein CaCl, was eliminated from the reaction, producing metal assaying 99.8 pct Th. Further work by Lilliendah118 howed that a coarser metal could be obtained by the substitution of ThC1, or ThOC1, for oxide with consequent advantage of stability to atmospheric reaction. Reports on the technology of thorium developed in Germany during World War II have been made by Espe."' Thorium powder of 99.5 pct Th was obtained by reduction of the oxide by calcium. Screening to —200 mesh, compacting with about 20 tsi, and sintering in vacuo at 1320" to 1360°C for 3 hr resulted in a porous sinter cake. The sinter cake was sufficiently ductile to be worked into bar, wire, and sheet which could be employed as electrode materials.

Jan 1, 1957

By W. B. Gogarty, W. C. Tosch

A new recovery process for producing oil under both secondary and tertiary conditions utilizes the unique properties of micellar solutions (also known as microemulsions, swollen micelles, and soluble oils). These solutions, which displace 100 percent of the oil in the reservoir contacted, can be driven through the reservoir with water and are stable in the presence of reservoir water and rock. Basic components of micellar solutions are surfactant, hydrocarbon and water. They may also contain small amounts of electrolytes and co surfactants such as a1cohol.r. The specific reservoir application dictates the type and concentration of each component. A salient feature of [he process is the capability for mobility control. Micellar solution slug mobility, by way of viscosity control, is made equal to or less than the combined oil and water mobility. Mobility control continues with a mobility buffer that prevents drive water from contacting the micellar solution. Laboratory and field flooding have proven that the process is technically feasible and that surfactant losses by adsorption on porous media are small. Introduction projects are under way to recover the maximum amount of oil under the most favorable economic conditions.' : New techniques are being developed to increase oil recovery,3" Polymer solutions are becoming an important means of controlling mobility in a waterflood. Thermal methods such as in-situ combustion and steam injection are being used in reservoirs containing highly viscous crudes. Surfactant flooding is receiving attention as a method of reducing interfacial tension to increase recovery.*'" Exotic recovery processes have been considered primarily for ' perations. Economics are unfavorable in most cases for tertiary recovery. studies at the Denver Research Center of the Marathon oil CO. have led to a new oil recovery method.* Micellar solutions (sometimes called microemulsions, swollen micelles, and soluble oils) are used to recover oil by miscible-type waterflooding. Basically, these solutions contain surfactant, hydrocarbon, and water. The method can be used in either secondary or tertiary operations. First, thc concept of thc process is considered in terms of the requirements for an effective miscible waterflood ing operation. Next, micellar solution properties are described including structure, composition, and phase behavior with reservoir fluids. Fluid characteristics are then considered as related to mobility control, and, finally, laboratory and field results are presented to illustrate the efficiency of the process. Concept of the Process Unit displacement efficiency and conformance determine the effectiveness of any oil recovery mechanism. In theory, a miscible waterflood should be capable of a 100-percent unit displacement efficiency with a correspondingly high conformance. Requirements for the slug of a miscible waterflood include (1) 100-percent displacement of oil in the reservoir contacted, (2) controllable mobility, (3) the capability of being driven through the reservoir with water, (4) a low unit cost to enhance economics, and (5) the ability to remain stable in the presence of reservoir water and rock. Micellar solutions satisfy requirements for the slug of a miscible waterflood process. Our discovery that these solutions acted as though they were miscible by displacing all fluids in the reservoir and by being displaced by water solved the miscibility problem. Adequate mobility control is possible by variations in solution viscosity through compositional changes. Economic requirements are met since micellar solution costs below $6/bbl appear possible, Mi cellar solutions stabilize surfactant in the presence of reservoir rock and water, thus reducing the importance of the problem of surfactant loss by adsorption. Fig. 1 illustrates schematically how these solutions are used. Operations start with injection of a micellar solution slug that serves as the oil displacing agent. Next, a mobility buffer of either a water-external emulsion or water solution containing polymer (thickened water) is injected to protect the slug from water invasion. Finally, drive water (water used in a regular waterflood) is injected to propel the slug and mobility buffer through the reservoir. Reservoir oil and water are displaced ahead of the slug, and a stabilized oil and water bank develops as shown in Fig. 1. Stabilized bank saturations are independent of original oil and water saturations. This means that, for a particular type of reservoir, the displacement mechanism is the same under secondary and tertiary recovery conditions. Oil is produced first in a secondary operation. For tertiary conditions, water is produced first. Movement of the slug through the reservoir is stabilized by the mobility buffer. An unfavorable mobility ratio usually exists at the interface between the buffer and drive

Jan 1, 1969

By T. H. Alden

Using alternating tension-compression straining, the hardening of magnesium oxide single crystals was studied up to large stresses and strains. At 0.25 pct plastic strain amplitude, the hardening curve is approximately linear with slope 25,000 psi from the shear yield stress, 7 to 8000 psi, to 35,000psi. Above this stress, the slope decreases. The strain hardening behavior of MgO is considered qualitatively similar to that of metal single crystals. The relatively high stress attainable by strain hardening is associated apparently with the high yield stress on the cross-slip system, (001) <110>. Cleavage fracture during testing is uncommon. It is argued that the centers of high internal stress at glide band intersections, at which cracks tend to nucleate, are dispersed by cyclic strain. Special features of the glide band structure produced by cyclic strain and revealed by dislocation etch pits, support this view. Strain hardened MgO has mechanical properties greatly superior to the as-received material: yield stress, greater than 100,000 psi; elongation to fracture about 1 pct. A material is said to strain harden if the yield stress increases with an increment of plastic strain. This definition is usually applied for straining done in one direction, but is also applicable when the strain direction is periodically reversed, Fig. 1. For certain metal single crystals, data are available which permit a comparison of the hardening behavior for cyclic straining and for tension straining.&apos;-4 With certain qualifications, these data show that the same processes of hardening are operative in each type of test.5 Despite this fact, the importance of the technique is not immediately evident, although tension-compression studies of the common metals appear to suggest some deficiencies in theories of strain hardening developed exclusively on the basis of tensile tests. However, a recent observation suggests that the cyclic straining method may be very useful for studying semibrittle crystals in which large plastic strains are not accessible in unidirectional testing. The observation is that zinc crystals, when strained in tension-compression at -52°C, do not fail by cleavage at low stress (-500 psi)6 as they do in tension, but harden to a limiting stress of more than 5000 psi over a total plastic strain of about 600 pct.2 An important characteristic of the behavior of zinc crystals is the high stress, relative to the yield stress, attainable by strain hardening. By comparison, the hardening of aluminum single crystals tested by an identical technique saturates at 1100 psi. This difference is best explained by the cross-slip hypothesis of dynamic recovery.7,8 In zinc, cross slip is difficult because of the high yield stress for glide on planes other than the basal plane in the < 1120 > zone. The present work was undertaken in order to test whether these methods and ideas are applicable to other materials. Magnesium oxide single crystals, in common with most crystals of the rock-salt structure, deform plastically but fail by cleavage after a small strain when tested in tension. It was hoped that larger strains would be attained using tension-compression. There is, in addition, evidence 8a which shows that slip on the probable cross system, (001) < 110>, is difficult in magnesium oxide; it may therefore be possible to attain high stresses by strain hardening. 1) EXPERIMENTAL PROCEDURE Experimental methods used in this study were based in part on techniques reported in papers of Stokes, Johnston, and Li.&apos; MgO blocks, purchased from Norton Co., were used without further annealing. Specimens were cleaved to dimensions approximately 0.125 in. sq and 1 in. in length. The gage section, formed by chemical polishing, was sprinkled with 280 mesh silicon carbide particles in order to introduce fresh dislocations. The crystals were then cemented into cylindrical aluminum adapters and clamped in an Instron testing machine. One of two alternating straining programs was used. In the first, total cross-head travel was established and increased in steps after various numbers of cycles. In the second, a capacitance gage was used to directly measure the elongation of the specimen and the crosshead was controlled so as to keep the plastic strain amplitude constant. The straining was always symmetrical with respect to the initial, zero strain condition. While both procedures produce strain hardening, only the latter permits a measure of the total plastic strain so that hardening curves may be drawn. Constant plastic strain amplitude tests were done

Jan 1, 1963

By Oren C. Baptist, Carlon S. Land

Laboratory research has been conducted to evaluute the effect of clay hydration on the permeability to gas of water-sensitive reservoir sands. Samples of a .sandstone containing trace amounts of montmorillonite and a sample of montmorillonite were .studied in the laboratory to detertnine whether swelling or dispersion was the cause of permeability reduction in these samples. Heliuin, containing various amounts of water vapor, was used to hydrate the clay minerals and to determine the gas permeability at various stages of clay hydration. The amount of water adsorbed by the samples using this method is small. The nonwetting-phase permeability at higher water saturations war investigated by saturating the with water and measuring the permeability to humid helium while decreasing the water saturation, Relative-permeability curves obtained from results of these procedures were used to estimate the effect of the swelling of trace amounts of mont/tlorillonite on the permeability of the .samples. Most of the damage to the permeability when reservoir sands containing trace amounts of montmorillonite are exposed to fresh water is due to dispersion and movement of clays. Blockage of pores by the increased volume of expanded montmorillonite is believed to result in permeability damage that is small in comparison to the observed damage to the samples tested. INTRODUCTION Studies have shown that permeability is severely damaged when sands containing only small amounts of montmorillonite are contacted by fresh water.15 When samples of sands containing large amounts of montmorillonite are placed in fresh water in the laboratory, these samples may completely disintegrate, forming an unconsolidated mass of larger volume than that occupied by the dry sample." In this case, it is apparent that the swelling of montmoril-lonite has destroyed the pore structure of the sand. If only a trace of montmorillonite is present in a sand. samples may remain intact when saturated with water, although the permeability to water is a small fraction of the gas permeability of the dry sample. Many workers in the field of water sensitivity have attributed this reduction in permeability to the blocking of pores and reduction of pore size by the increased volume occupied by expanded mont- niorillonite. if the sand contains a detectable amount of montmorill&apos;onite or mixed-layer clay containing rnontmorillonite. Logically3 the smaller amount of montmorillonite present in a sand, the smaller should he the effect of montnlorillonite swelling on permeability; however, the quantity of montmorillonite sufficient to cause severe damage by swelling is not known. Although hundreds of samples have been tested in our laboratory, no correlation has been established between the amount of montmorillonite in samples and the permeability reduction caused by fresh water. To many petroleum engineers, the phrase "clay swelling" is synonymous with "water sensitivity", or "permeability reduction" implying that any formation damage due to the hydration of clays is caused by swelling. Although all clays adsorb water on their surfaces, montmorillonite is the only clay mineral commonly found in reservoir rocks which adsorbs water between intercrystalline layers, resulting in expansion of the clay particle. As montmoril-lonite swells, the first few layers of water adsorbed between platelets are strongly held and well oriented, and the montmorillonite retains its crystalline structure, although expanded. As swelling of sodium montmorillonite continues, the platelets become farther apart and the forces orienting the platelets in the crystalline structure become weaker, resulting in a less orderly orientation of platelets. In an abundance of water, small groups of platelets may become detached from the original monl-rnorillonite particle and may be dispersed throughout the water phase. Because of its swelling properties, sodium montmorillonite is very easily dispersed in water. Particles of other clay minerals. such as illite and kaolinite may also be dispersed in water. causing water sensitivity of sands not containing montmorillonite. The presence of an immobile layer of water adsorbed on the surface of clays has been considered a possible cause of the low permeability to water of dirty sands. Grim states that the thickness of the layer of immobile water held by sodium montrnorillonite is three nlolecular layers or 7.5 A (angstroms), with some orientation of water extending to 100 A. Assuming a very thick, immobile water layer adsorbed on the surface of a pore represented by a capillary tube, the maximum effect of the water layer on permeability can be calculated. Using a pore radius of 10 &apos; cm and an immobile water layer of 50 A. the calculation shows the permeability to be reduced only 2 per cent. Similar calculations can be used to show that the effect of electro-osmotic counterflow is of the same order of magnitude as that of bound water. The reduction of the permeability to water by either an immobile water layer

Jan 1, 1966

By Ralph B. Stevens

INTRODUCTION Underground fires continue to be one of the most serious hazards to life and property in the mining industry. Although underground mines are analogous to high-rise buildings where persons are isolated from immediate escape or rescue, application of technology to locate and control fire hazards while still in their controllable state is slow to be implemented in underground mines. Even in large surface structures such as hotels, often only fire protection systems which meet minimal laws are implemented due to the high cost of adding extensive extinguishing systems, isolation barriers, alternate ventilation, escape routes and alarm systems. Incomplete and ineffective protection occasionally is evidenced where costs would not seem to be a factor, such as the $211 million MGM Grand Hotel fire November 21, 19801. Paramount in increasing fire safety and decreasing the threat of serious fire is early warning followed by proper decision analysis to perform the correct action. However, very complex fire situations can be produced in structures such as high-rise buildings and underground mines simply because of the distances between the numerous fire-potential locations and fire safe areas. Other complexities arise when normal activities occur that emit products of combustion signaling a fire condition to a sensitive fire/smoke sensor. For example, the operation of diesel equipment or the performance of regular blasting can produce combustion products that reach the sensitive alarm points of many sensors2. Smoke detectors for surface installations provide fire warning when occupants are at a distant location or when sleeping, thus greatly reducing injuries and property damage. However, when installed in the harsh environments of underground mines, fire and smoke detection equipment soon becomes inoperative, unreliable, or requires excessive maintenance. The U.S. Bureau of Mines has performed many studies and tests to improve fire and smoke protection for underground mine workers3. This paper describes several USBM safety programs which included in-mine testing with mine fire and smoke sensors, telemetry and instrumentation to develop recommendations for improving mine fire safety. It is hoped that the technology developed during these programs can be added to other programs to provide the mining industry with the necessary fire safety facts. By recognizing fire potentials and being provided with cost-effective, proven components that will perform reliably under the poor environmental conditions of mining, mine operators can provide protection for their working life and property equal to that which they provide for themselves and their families at home. The basis of this report is two USBM programs for fire protection in metal and nonmetal mines4,5 and one coal program6. The data was collected beginning in May 1974 and continuing through the present with underground tests of a South African fire system installed at Magma Mine in Superior, Arizona, and a computer-assisted, experimental system at Peabody Coal Mine in Pawnee, Illinois. The conduct of each program was as follows: • Define the problem and its magnitude in the industry • Develop concepts to solve or diminish the problem • Review available hardware or systems approaches to fit the concepts • Install and demonstrate the performance of a prototype system through fire tests in an operating mine. MINE FIRE FACTS Whether in coal or metal and nonmetal mines, the potential severity of fire hazard is directly related to location. As shown in Figure 1, fire in intake air at zones A, B, C or D can cause contamined air to route throughout the mine quickly if not detected, isolated or rerouted. Causes and location of former metal and nonmetal fires are represented in Table 1; the cause and location of fatalities and injuries is shown in Table 2. Coal-related fires and their impact on deaths and injuries are graphed in Figure 2; their locations are described in Table 37. Significantly the table shows that the hazard to personnel was three times greater for fires occurring in shaft or slope areas, and the percentage of deaths and injuries was four times that of other areas. Number of Persons Affected A 129-mine sample indicated that from 8 to 479 employees per shift work in underground metal and nonmetal mines, and that deeper mines have larger populations, as shown in Figure 3. Coal mining relates similar employment, and a 16-state sample of 670 mines employing at least 25 persons shows the distribution in Figure 4. Drift mines accounted for 58 percent of the sample but employ only 45 percent of the underground workers.

Jan 1, 1982

By W. J. Maraman, D. R. Harbur, J. W. Anderson

A device for rapidly quenching liquid metals into thin platelets has been developed at the Los Alamos Scientific Laboratory. This rapid quenching equipment is built around the technique of catching a molten drop of metal between a rapidly closing plate and a stationary plate. The design and operation of this unit are described. The closing speed of the smasher plate at impact is 12.6 ft per sec. The quenching rate for this device is controlled by the interface resistance between the plates and the platelet, and is dependent upon the heat content and density of the material being quenched. The initial quenching rate down to the freezing point of the platelet material is lo5º to 106ºC per sec. After an isothermal delay, which is poportional to the heat of fusion of the platelet material, the final cooling rate down to the temperature of the smaslier plates is l04ºto 105cº per sec. RAPID heating of metals by capacitor discharge and other methods has provided the metallurgist with a useful tool for probing into the kinetics of phase changes and the many nonequilibrium phenomena which occur during rapid temperature changes. Equally interesting studies can also be made on metals and alloys which are rapidly cooled from the liquid state.&apos; Studies in this field have been limited, however, because the rates at which metals could be cooled were many orders of magnitude slower than the rates possible for heating. In recent years many new laboratory methods have been developed to rapidly cool metals from the liquid state to ambient temperature and below.2"4 All of these methods involve spreading a liquid drop of metal into a thin foil in a very short time. The methods developed have varied from ejecting a drop of molten metal at the inside surface of a rotating cylinder or stationary curved plate to catching a falling drop of molten metal between rapidly closing plates. The equipment which has been developed at the Los Alamos Scientific Laboratory for rapidly cooling molten materials uses the latter of these two approaches. The basic design, operation, and initial results of this rapid quenching device are given in this report. APPARATUS The drop smasher, which is now being used to obtain rapidly cooled metal foils, is shown in Fig. 1. Basically the device consists of a smasher plate which is driven by a solenoid into a stationary plate. The solenoid is activated by a drop passing through the photoelectric cell and is powered by discharging an adjustable 350-v capacitor bank with a 66-amp peak current into it. This power supply is designed so that the solenoid is powered for 2 m-sec after plate closure to minimize the rebound effect. There is an adjustable time-delay mechanism between the photoelectric cell and the solenoid. Both smasher plates have changeable inserts so that a variety of materials can be used to smash the molten drop. The shaft of the moving plate is guided in an adjustable housing which has ball-bearing walls. The cabinet shown to the left of the drop smasher in Fig. 1 contains the power supply and receiver for the photoelectric cell, the time delay mechanism, and the capacitor bank. The drop smasher can be placed inside a vacuum chamber, for use with radioactive materials, with the upper plate forming the lid, as shown in Fig. 2. On top of the vacuum lid is an induction coil, powered by an Ajax induction generator, which is used to melt drops from the end of the rod extending through the vacuum seal on top the quartz tube. OPERATION The drop smasher shown in Fig. 2 is operated in the following manner. The smasher plates are separated and the unit is lowered into the vacuum chamber using a pressurized cylinder. The induction coil, quartz tube, and lid with sliding vacuum seal are then assembled on top the vacuum chamber. A rod of the material for rapid quenching studies is connected to the rod extending through the sliding vacuum seal. The vacuum chamber is then evacuated and the desired atmosphere established. The photoelectric cell is turned on, and the capacitor bank is charged and armed. Power is supplied to the induction coil, and the rod of material for rapid quenching studies is lowered into the induction field. A molten drop forms on the end of the rod, drops off, falls through the light beam of the photoelectric cell, and is then caught between the smasher plates. .

Jan 1, 1970

By S. Nakajima, H. Okazaki

Quantitatiue studies of the deformation texture in drawn tungsten wives were made by the X-vay dif-fractottletetr. Experimental results show that the diffraction Intensities are equal to tilose pvedicted from the (1 10). fiber lexlure but the angxla), spreads of. diffraction peaks in the pole distribution curres are different for different diffraction planes and directions. For this reason a modified (110) fiber lextuve model, in which a kind of anisotropy is assumed, is proposed to explain the results. According to this model the poles lying on a line directing front the (110) to the (110) poles in the (1 10) standard stereograpllic projection should show spreads which are different from those lyitlg on a line directing from the (001) to the (001) poles, which is confirmed by the experiments. The anisolvopy and the spveads of the pole positions are large at the outer part of the wires and decrease gradually lowards the inside of the wire. The possibilily of occurrence of such anisolropy in irrelals with fcc stvuctures is discltssed. THE deformation texture of drawn tungsten wires has been assumed by different investigators to be the simple ( 110) fiber texture.&apos; Recently, however, Leber2,3 has shown that a swaged tungsten rod has a cylindrical texture. It changes gradually to the (110) fiber texture by drawing through dies. However, even after drawing to 0.25 mm in diam, the cylindrical texture can still be found in wires together with the (110) fiber texture. This was deduced from the pole figures obtained from the longitudinal section of these wires. Use was made also of quantitative measurements of the pole distribution curves. Leber stated that the angular spread of the pole distribution curves (henceforward called dispersions) are quite different for (400) 45 deg and (400) 90 deg: the former is always larger than the latter. This inequality is accompanied by deviations of the diffraction intensities from the theoretical values for the ( 110) fiber texture. Bhandary and cullity4 have reported similar results on iron wire and explained them by assuming a cylindrical texture. Both Leber3 and Bhandary4 used only the results of the (400) reflection for the determination of the dispersion. The pole figures found by Leber3 and by Rieck5 are largely different. The model given by Leber to explain the effects is in the authors&apos; opinion in some respects unsatisfactory, especially if one looks at other than the (400) reflections. Intensities and dispersions of diffraction peaks are conclusive factors for the determination of the fine structure in wire textures. For this reason we studied them extensively to come to a model which is more suitable to fit the facts. In the following, after giving the experimental set-up, we report about measurements of X-ray diffraction on drawn tungsten wires. Different models to describe the experimental results will be discussed. EXPERIMENTAL GO-SiO2-A12O3 doped tungsten wires drawn to 0.18 mm in diam were used for the measurements. The wires were chemically etched to various diameters down to 0.03 mm. Measurements were carried out for the different wires in order to determine the dependence of the texture on the radius. The wires were cut to pieces of 10 mm length and fixed with paste closely against each other on a flat, polished glass plate. Parallelism of the wires with the surface of the glass plate should be adequate. For the diffraction studies three different X-ray sources were applied, respectively, giving the CuK,, FeK,, and FeKp emission. The measurements were carried out with a diffrac-tometer with a GM counter. The latter was fixed to a certain diffraction angle 20hkl and the diffraction intensity was recorded as a function of the angle of rotation of the specimen around the axis, lying in the specimen surface and perpendicular to the wire axis, as shown in Fig. 1. Measurements were also done with the detector at angles slightly deviating from the diffraction maxima The measured intensities in this case were taken to be equal to the background level. The deviations were chosen as small as possible but large enough to eliminate the influence of the diffraction maxima. The useful range of the rotation angle x of the specimen is generally limited by the wavelength of the X-rays. We have: where and cp is the angle between the wire axis and the normal of the diffraction plane. Intensity measurements were made to find the necessary corrections for counting loss of the GM counter and for distortion resulting from such effects as absorption of X-rays and from inclination of the reflection plane under study with respect to the surface of the specimen. The counting loss was esti-

Jan 1, 1968

By R. H. Kolb

A long term project at Shell Development Co.&apos;s Exploration and Production Research Laboratory has been the improvement of the accuracy and the ease of BHP measurements. As a result of these efforts, two complete and separate systems have now been built for the automatic logging of BHP variations. The first of these is a small-diameter instrument suitable for running through production tubing on a single-conductor well cable. During the development of this instrument, as much emphasis was placed on providing a high degree of usable sensitivity and repeatable accuracy as on obtaining the advantages of surface recording. The second system combines the benefits of automatic, unattended recording with the convenience of a permanently installed Maihak BHP transmitter.&apos; THE CABLE INSTRUMENT For many years the standard instrument for BHP determination has been the wireline-operated Amerada recording pressure gauge or one of several other similar devices. This gauge records on a small clock-driven chart carried within the instrument, and although relatively precise readings from the chart are possible, they are difficult to ob-tain. a Both the maximum recording time and the resolution of the time measurements are limited by chart size, and when a slow clock is required for long tests, the precision of the time measurement is often inadequate. Since it is impossible to determine the data being recorded until the gauge has been returned to the surface, wasted time often results when a test is protracted beyond the necessary time or when it is terminated too soon and must be re-run. Clock stoppage or other malfunctions which would be immediately apparent with surface recording remains undetected with down-hole recording; the test is continued for its full term with a consequent loss in production time. As new uses for subsurface pressure data evolved, the shortcomings of the wireline instrument became increasingly apparent, and the concurrent development of a surface-recording pressure gauge and the associated high-pressure well cable service unit&apos; was undertaken. Description of the Instrument Because of its ready availability and advanced degree of development, the Amerada bourdon-tube element was chosen as the basic pressure-sensing device. This element converts a given pressure into a proportional angular displacement of its output shaft, and a suitable telemetering system was designed to measure accurately the extent of this displacement and to transmit the measurement to the surface and record it. The telemetering system furnishes a digital record printed on paper tape by an adding machine-type printer. The present arrangement provides a resolution of one part in 42,000 over the angular equivalent of full-scale deflection, giving a usable sensitivity of better than 0.0025 per cent of full scale. An additional refinement simultaneously records on the tape the time or the depth of the measurement, also in digital form. When the instrument is placed in operation, an adjustable programer can be set to initiate a read-out cycle automatically at selected time intervals. When subsurface pressures are changing rapidly, readings may be recorded as frequently as once every 10 seconds; when pressures are more nearly stabilized, the period between readings may be extended to as much as 30 minutes. Because the instrument is surface-powered as well as surface-recording, the maximum period of continuous logging is (for all prac. tical purposes) unlimited. The subsurface instrument is a tubular tool, 1 1/4-in. in diameter and 6.5 ft in length, operating on 12,000 ft of conventional 3/16-in. IHO logging cable. The transmitting section, mounted above the bourdon-tube element in place of the regular recording mechanism, contains no fragile vacuum tubes or temperature-sensitive transistors. This unit has been laboratory-tested to 1 0,000 psi and 300°F and has performed dependably during a number of field operations. The down-hole transmitting arrangement can be fitted to any standard Amerada pressure element, regardless of range and with no modification of the element itself. Calibration To obtain a repeatability commensurate with the sensitivity and resolution of the instrument, it was necessary to develop a special calibrating technique. The manufacturers of the Amerada recording pressure gauge claim an accuracy of only 0.25 per cent of full scale, which is a realistic figure for normal calibrating and operating procedures. An exhaustive investigation was made of the errors inherent in the bourdon-tube element, itself, independent

By Hollis L. Caswell

The present status of integrated circuits utilizing. superconductive switching. elements is reviewed with special attention given to fabrication techniques, methods for interconnecting completed circuits, and refrigeration requirements. Cryoelectronics has been largely an "inte- grated-circuit" technology since its conception because the switching speed of superconductive devices is attractive only when these devices are fabricated with thin-film techniques. It is true that cryotron circuits can be constructed from wires of appropriate materials (as indeed was done by Dudley Buck 1 in his early investigations) but these circuits will switch in times characteristic of milliseconds whereas similar circuits fabricated by thin-film methods have potential switching times of nanoseconds. Furthermore, cryo-electronic devices such as the cryotron lend themselves readily to fabrication by thin-film techniques since these components may be made from polycrys-talline thin films and are relatively insensitive to the presence of impurities (as measured by semiconductor standards). Therefore, during the past decade considerable effort has been devoted to developing techniques for batch fabricating circuit arrays containing superconductive switching elements. Technology had developed to the point several years ago that fabrication of cryoelectronic arrays containing up to one hundred devices was rather straightforward. However, larger arrays containing between lo4 and 106 components which are required for commercial development of cryoelectronics still pose very severe yield problems. Thus in a sense cryoelectronics found itself in 1962 at the point semiconductor technology finds itself today; namely, individual devices and small groups of integrated devices could be fabricated with acceptable yield and the outlook for building larger integrated-circuit arrays was bright. Unfortunately, problems associated largely with yield have made fabrication of these larger arrays difficult. Unlike semiconductor technology, cryoelectronics had to solve the problems of large-scale integration before it could become economically attractive. This has proven to be a sizable burden to bear. Since several reviews exist on superconductivity,2 superconductive devices,3 and cryoelectronic technology, no attempt will be made in this paper to summarize these areas. Instead a few specific topics will be dealt with in more detail. First, a brief description is given of selected superconducting switching and storage devices with special attention to several metallurgical techniques which improve the performance of these devices. Second, techniques used to fabricate cryoelectronic devices are described with emphasis on problems affecting yield. Third, techniques for interconnecting a number of cryoelectronic planes are described. And last, refrigeration of cryoelectronic components is discussed briefly since the low operating temperature of superconductive devices is an important consideration in this technology. SUPERCONDUCTING STORAGE AND SWITCHING DEVICES The basic superconductive switching device is the thin-film cryotron. The geometry of this device is attractively simple, since it involves only the intersection of two lines that are electrically insulated from each other. The switching element (gate) and control element (control) of a crossed-film cryotron are arranged as illustrated in Fig. 1. The material for the gate is selected to permit the gate to be switched from the superconducting to the normal (resistive) state by the application of a control current. Tin, which has a critical temperature (T,) of 3.7°K, is commonly used for the gate and the cryotron is operated at a temperature just below T, (for example, 3.5°K). The control material (normally lead, with T, = 7.2°K) is chosen so that the control is never driven normal during circuit operation. To improve cryotron operation, a ground plane, also of lead, is placed under all of the circuitry to act as a diamagnetic shield and improve the current-density uniformity across the width of various thin-film elements. Normally, line widths vary from 0.005 to ^ 0.020 in. and film thicknesses from 300 to 10,000A, although new fabrication techniques make narrower lines feasible. In fabricating cryotrons it is important that the edges of the gate elements be geometrically sharp to avoid undesirable switching characteristics associated with a thinner edge region, Fig. 2. One technique which has been used extensively to form patterns consists of placing a physical mask containing the film pattern between the evaporation source and the substrate and depositing through the mask. Film strips formed in this manner possess a penumbra at the film edges due to shadowing of the evapor-ant under the mask. Several techniques have been proposed for minimizing effects due to this penumbra. One of the more promising metallurgical techniques

Jan 1, 1967

By J. Philibert, A. G. Guy

Diffusion in the presence of deformation was studied by the method of vacuum dezincification of copper-rich and silver-rich solid solutions containing 7 to 30 pct Zn. The specimens were designed to permit the study of diffusion in separate portions of a given specimen characterized by strain rates ranging from essentially zero to approximately 10 sec-. No effect of deformation on diffusion was observed. BEGINNING with the work of Buffington and Cohen: interest in the question of the effect of stress or strain on diffusion has largely been concentrated on the enhancement of diffusion in specimens subjected to Continuous plastic deformation. The present research is a contribution to this limited area. However, as a preliminary to focusing attention on this special topic, it will be desirable to make a broad survey of the larger question, especially since there has been considerable foreign work in areas outside those of current interest in the United States. Since most of the topics referred to in the following section are both complex and imperfectly understood at present, it has been expedient in most instances to offer only a guide to the general nature of the work rather than a critical evaluation. PREVIOUS WORK The effect of elastic stress on diffusion has received considerable attention, especially with regard to the thermodynamic driving force for diffusion. The thermodynamic treatments have been based on the work of Gibb, Voigt, Planck, and Leontovich.&apos; Konobeevskii and Selisski6 made a first attempt at treating the problem in 1933, and Gorskii7 a few years later gave a solution applicable to single crystals as well as to polycrystalline specimens. In 1943 Konobeevski8 published treatments that have been the basis of much Russian work up to the present. For example, Aleksandrov and Lyubov used his work in explaining the velocity of lateral growth of pearlite. Early work in the United States was that of Mooradian and Norton, which showed that lattice distortion tends to be relieved before it can significantly affect the diffusion process. Druyvesteyn and Berghoutl1 observed a slight effect of elastic strain on self-diffusion in copper, while de Kazinczy12 found that both elastic and plastic deformation increased the rate of diffusion of hydrogen in steel. On the other hand, Grimes58 observed no effect of either elastic or plastic straining on the diffusion of hydrogen in nickel. High-frequency alternating stresses have been reported by various investigator s13-l5 to increase the rate of diffusion. A special form of elastic stressing is the imposition of hydrostatic pressure, a condition that is amenable to Conventional thermodvnamic analysis. Most of the experimental results in this area are consistent in showing a slight decrease in diffusion rates at high pressures.16-l8 Although Geguzinl reported a pronounced effect of relatively small pressures, Barnes and Mazey20 failed to Corroborate this finding, while Guy and Spinelli21 advanced an explanation of the phenomenon observed by Geguzin. It has been recognized that the thermodynamic treatment of diffusion phenomena in an arbitrarily stressed body is complicated by the fact that the desired state of quasi-equilibrium of the shear stresses cannot be maintained during a general diffusion process. However, attempts have been made by Meix-ner22-24 and Fasto to treat certain restricted cases, such as relaxation. FastovZ7 has also incorporated the general stress tensor into the thermodynamics of irreversible processes. The lattice strain that accompanies the formation of a solid solution has been the subject of much study,28-s0 and indirectly it has entered into many recent theories of diffusion. However, some Russian investigators31&apos;32 have taken other views of this matter and have predicted large effects on diffusion rates because of concentration stresses.o In completing this brief resume of previous work involving elastic strains and before proceeding to a consideration of the effect of continuous plastic deformation, it should be pointed out that deformation of various additional types may also influence diffusion. The effect of cold-working on subsequent diffusion has been studied directly by AndreevaS and by Schumann and Erdmann-Jesnitzer, while indirect evidence has been obtained by Miller and Guarnieri and by Vitman.38 Thermal stresses may also influence diffusion, contributions to this subject having been made by Fastovs7 and by Aleksandrov and Lyubv. The work of Johnson and Martin,o Dienes and Damask,3Band DamaskS considered the question of radiation-enhanced diffusion. In considering previous work on the subject of plastic deformation and diffusion, attention will be directed to those studies concerned primarily with diffusion rather than with its relation to Creep, e.g., the work of Dorn, or to the acceleration of diffusion -controlled reactions. Observations of the effect of

Jan 1, 1962