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By H. E. Cline, J. L. Walter

Grain boundary sliding and migration were studied in pure aluminum bicrystal and polycrystal samples with two-dimensional grain structure. Scratches, 50 P apart, were used for measurement of sliding and migration distanceso. Samples were deformed at constant rate at 315C and events recorded continuously on wrotion picture film. Electron micrograPhs of boundary-scratch intersections were obtained. Yield and flow stress values were measured. The sequence of sliding and migration events for a three-grain junction is described in detail. Sliding depended only on the resolved shear stress imparted to the boundary. Sliding was accowmodated by formation of shear zones in grains opposite triple points and adjacent to curved boundaries. These shear zones provided the driving force for grain boundary migration. Migration caused rumpling of the boundaries, decreasing the sliding rate. Sliding and migration generally began at the same time, occurred simultaneously and ended at the same time. In the bicrystal, sliding and migration rates were proportional. Initial sliding rules of 5 X joe cm per sec. were measured for the polycrystal and bicrystal samples. These sliding rates agree wilh the internal friction experirnents of K;. The observations seem consistent with a viscous boundary sliding nzechanism. GRAIN boundary sliding is the translation of one grain relative to its neighbor by a shear motion along their common boundary. Sliding is thought to be an important mode of deformation at elevated temperatures and at low strain rates such as prevail in creep,' and perhaps in the area of superplastic behavior.2"4 Although much work has been done to investigate grain boundary sliding, the effort has not led to the identification of a mehanism. KG showed that grain boundaries in aluminum exhibit a viscous nature under very small displacements of internal friction measrements. Various dislocation mechanisms have been proposed but are without conclusive experimental support. Attempts to relate sliding to 6's viscous boundaries have been unsuccessful in that measured rates of sliding are always several orders of magnitude lower than KG'S results would predict.= In bi crystals7and polycrystalsR of aluminum tested under constant load, the grain boundary sliding was found to be proportional to the total creep elongation which indicated that sliding might be controlled by deformation of the grains. Shear zones were observed to extend beyond grain boundaries at triple points to accommodate the sliding.8 Surface observations brought forth the opinion that sliding and migration occurred alternately, in sequence.' Measurements of sliding at the surface have been criticized because they might not be representative of the interior of the sample. Generally speaking, it seemed that much of the previous work and knowledge was based on observations made at relatively low magnification and examination of samples after deformation had been accomplished. Thus, it was the purpose of the present study to continuously record, at high magnification, the events occurring during the deformation of pure aluminum. Samples with two-dimensional grain structures were used to simplify interpretation of the results. The sliding and migration of small areas of many samples were continuously recorded by time-lapse motion pictures. Replicas of the surface were used to provide high-resolution electron micrographs. These observations, coupled with tmsile strength data, provide sufficient information to arrive at an understanding of the phenomenon. EXPERIMENTAL PROCEDURE An ingot of 99.999 pct A1 was rolled to sheet, 0.127-cm thick. Tensile specimens, with a gage length of 0.85 cm, were machined from the sheet. Bicrystal tensile specimens, of the same dimensions, were spark cut from a large bicrystal ingot. The grain boundary was oriented at 45 deg to the tensile axis. The surfaces of the tensile samples were ground flat on fine metallographic paper and were then electropolished in a solution of 75 parts absolute alcohol and 25 parts of perchloric acid. The solution was cooled in an ice-water bath. Using a weighted sewing needle suspended from a small pivot on a precision milling machine, a grid of fine scratches, 50 p apart, was scribed on one surface of the sample. The polycrystalline samples were then annealed in hydrogen for 15 min at 350" to 400°C to produce a two-dimensional grain structure of about 0.2-cm average grain diameter which would not undergo further growth at the test temperature, 315OC. Examination of both surfaces of the samples showed that the grain boundaries were perpendicular to the surface of the polycrystal and bicrystal samples. A hot-stage tensile machine was constructed for use with an optical microscope as shown in Fig. 1. The specimen is shown mounted in the grips. The grips ride in V-ways so that the sample can be mounted without damage. The rear grip is free to slide so that when the sample expands during heating it is not put under a compressive stress. When the grips and samples are at temperature, the rear grip is locked in place by two set-screws. The other grip is connected to a synchronous drive motor which, through a worm gear and a fine-threaded rod, deforms the

Jan 1, 1969

By E. O. Jones, E. Whitehead

During the heating of cold-worked nickel silver, the tendcncy of the material to crack is well known. The present research deals with this question, and may conveniently be divided into the following sections: Changes in these alloys during heating and cooling, determination of the temperature at which cracking occurs, effect of grain size, quenching cracks, methods of overcoming annealing cracking. The work is far from complete, in particular the influence of impurities on this tendency has not been investigated, but the results so far obtained lead to certain definite conclusions, which are of theoretical and practical importance. Changes in Alloys During Heating and Cooling During the annealing of many metals at a temperature just below that at which recrystallization sets in, there is evidence of some change, the effect of which is to harden and embrittle the material. This effect has been most clearly demonstrated in the cases of aluminum, copper, brass, and nickel silver, and appears to be a common property of cold-worked metals and alloys, or, at any rate, the non-ferrous ones. The effect would obviously offer an explanation for certain types of annealing cracking, but the trouble is so much more common in the nickel silvers than in the other alloys that some special cause should be looked for. There is, however, fairly good reason for believing that similar cracking may occur in some of the brasses; D. Bunting1 suggests that the a brasses toward the saturation limit are subject to a transformation closely allied in nature to that known to occur in the nickel silvers at around 320" C. Although the existence of this critical temperature range was known, it did not necessarily follow that this transformation was responsible for the trouble under investigation, so the first portion of this paper deals with the attempts made to determine whether other critical changes might not occur in these alloys. There were already reasons for the belief that such would prove to be the case, as the mechanical properties of the nickel

Jan 1, 1926

By S. W. Kessler, R. B. Pond

Metal specimens were solidified through a measured thermal gradient so a free surface and the liquid-solid interface could be examined. A line structure was observed on the surface and a hexagonal structure on the interface. A model to explain these forms is proposed. NUMEROUS observations of the dendrite form have been made both in nonmetallic and metallic systems. From these, extrapolations have been made as to the probable dendrite form in pure metals. Observations of the dendrite form in pure metals, nevertheless, have been scanty. In general, these observations have been made on the skeleton dendrite after the mother liquid has been drained from around it, and a mechanism of the formation of the dendrite has been postulated from this solid form. Recent investigations have been conducted in an endeavor to make a study of the formation of the dendrite in several pure metals and the effect of several variables on this mechanism and final form. For these investigations, an apparatus was designed and constructed as shown in Fig. 1. It consists of a talc block containing a half-cylindrical depression, the end of which terminates in the conical recess of a copper block having an external attachment for cooling. A heating coil extends the length of the mold just beneath the lower limits of the cavity. The entire cavity for holding metal is coated with a thin film of graphite. Six thermocouples are equally spaced in the cavity and under the graphite, and six microammeters indicate the temperatures at the particular thermocouple stations. Readings were taken of all meters at the same instant time measurements were taken by photographing the panel of microammeters and a stop watch which was started at the beginning of the run. It was possible with this apparatus to solidify metals through a measured thermal gradient and to observe the progression of the liquid-solid interface with time by following the formation of the dendrite markings in the surface of the solid material. These

Jan 1, 1952

Lieut. Louis J. Brunel, now in France, was commissioned on July 27, 1917, as Second Lieutenant in the Engineers Reserve Corps, assigned to the 7th U. S. Engineers, Dec. 10, 1917, and has been with the American E. F. since Mar. 26, 1918. He was assigned to the staff of the General commanding the 5th Field Artillery Brigade, as Engineer Officer, on Aug. 6, 1918. E. Ross Housholder writes that "the record for pontoon bridge building was broken Sept. 25, 1918, by Section A, Co. 4, 5th Engineer Officers' Training School, at Camp Humphreys, Va., of which I am a member. The time was 15 min. 11 3/5 seconds. We then proceeded to break the record for dismantling in 9 min. 57 1/5 seconds. The length of the bridge section was 200 ft. The post band was sent out to meet us, and we feel proud of this record. I have met quite a few A. I. M. E.

Jan 11, 1918

By J. E. Neal, C. T. Naber, O&apos

Silicon thin films were deposited by electron beam evaporation in an ultrahigh vacuum onto (0001) and (1102) sapphire substrates. Attempts were made to correlate the structural properties of the deposited silicon films with the following: 1) substrate orientation, 2) substrate surface condition, 3) substrate temperature, and 4) deposition rate. The substrate temperatures were varied between 500° and 1000°C and the deposition rates were varied between approximately 50 and 700A per min. The following sapphire surface treatments were investigated: 1) annealing in the ultrahigh vacuum at 1200° C; 2) heating in a hydrogen atmosphere at about 1350°C; and 3) etching with silicon by evaporating silicon onto sapphire substrates heated to 1200° or 1300°C. Twinned silicon films were occasionally formed at substrate temperatures between the 800° and 1000°C on unprocessed mechanically polished substrates; however, the reproducibility and crystallinity of these films were generally poor. Single-crystal and twinned silicon films were formed at substrate temperatures between 700° and 1000°C on substrates which were silicon-etched at 1300°C prior to deposition. Fiber texture films were formed at substrate temperatures between 500° and 700°C. The (111) lattice plane of the silicon single-crystal films was parallel to the (0001) sapphire plane and the (100) silicon plane was parallel to the (1102) sapphire plane. TECHNIQUES are well-established for growing single-crystal silicon thin films on sapphire by chemical methods.'-* Vacuum epitaxial techniques have a number of advantages over chemical epitaxial techniques in the fabrication of thin film microcircuits.5 One of the most significant is that vacuum techniques are compatible with well-established procedures for forming vacuum-deposited thin-film resistors, capacitors, and interconnections. Salatna, Tucker, and young6 recently reported the formation of relatively poor crystalline-quality silicon films on sapphire by electron beam evaporation in a vacuum of about 7 x 10-7 Torr. The purpose of the investigation described here is to determine the relationships between the structural properties of silicon thin films deposited on sapphire substrates by electron beam evaporation in an ultra-high vacuum and the following: 1) substrate orientation; 2) substrate surface condition; 3) substrate temperature; and 4) deposition rate. The substrate temperatures were varied between 500° and 1000° C and the deposition rates were varied between approximately 50 and 700A per min. Two orientations of sapphire were used: (0001) and (1102). The thick-nesses of the films were between 8000 and 16,000A. The morphology and crystallinity of the deposited films and substrate surfaces were investigated by optical microscopy, electron microscopy, and electron diffraction. APPARATUS AND PROCEDURE A cross section of the ultrahigh-vacuum thin-film evaporator is shown in Fig. 1. The bell jar is stainless steel and copper gaskets are utilized at all seals. High vacuum is attained by a 6001iter per sec ion pump and a titanium sublimation pump. Sorption pumps are used to rough the system to a pressure of about 10 µ prior to starting the ion pump. Vacuums in the 10- 10 Torr range were attained after baking the system at about 250°C for 8 hr. Vacuums in the 10-8 to 10-9 Torr range were maintained during silicon evaporation. The silicon charges, which were cut from p-type single-crystal boules which had resistivities between 2000 and 4500 ohm-cm, were placed in the water-cooled copper crucible of a 180 deg bent-beam 5-kw electron beam evaporator. During evaporation, a molten zone was formed in the top center of the silicon charge, and the portion of the silicon charge in contact with the water-cooled crucible remained solid. The substrate heater, which has been described

Jan 1, 1969

By George Espey, George Sachs, G. B. Kasik

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually have been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,' the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin3-5 and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between

Jan 1, 1942

By G. B. Kasik, George Sachs, George Espey

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually have been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,' the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin3-5 and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between

Jan 1, 1942

By D. C. Jones

The term "coal-mine mechanization" is definable in several ways. In its general application it can mean the use of machines instead of manpower in each of the various mining activities necessary for the production of coal—so that under this definition a mine that uses mechanical coal cutters could be classed as a mechanized mine. Common usage, however, insists that a mechanized mine is one in which machines are used for the entire process of mining or extraction and transportation of the coal. For the purpose of this paper, then, the second definition of "coal-mine mechanization" will be used, and practices employed in mines where the greater part of the production is obtained through the use of mechanical loaders and conveyors will form the basis for this discussion. Physical Contact Hazards If we were to group all the hazards that accompany the use of mechanized equipment in a mine, the predominant class would be that which, for want of a better name, might be termed the "physical contact" hazards; that is, all the sources of danger that lead to accidents through physical contact of workmen with machines. A survey of accidents in a group of mechanized mines indicated that this class of hazards may be responsible for more than half the number of accidents in mechanized mining. For example, of 21 mining-machine accidents at one mine, 14 were of the physical contact type; of 14 loading-machine accidents at the same mine, 8 were the result of physical contact. Certain of these hazards are controllable through the use of guards— a guard over the cutting-machine bits when the machine is being trammed from place to place, or a chain or some similar locking device around the cutter chain, so that an accidental blow or push against the bit control will not cause the cutter chain to move. Other hazards, such as the possibility of a loader operator having his foot crushed by a crawler tread, or a brakeman being hit by a loader boom swung too far to one side while a car is being loaded, might be subject to control through the use of guard devices, but the reduction or elimination of all physical contact hazards by such methods does not appear feasible. Every accident of the physical contact type should he investigated to discover whether guards could have prevented it, but often the only way in which to combat these hazards will be through the awakened consciousness of each workman as to the danger that exists if he indulges in unsafe practices. A good approach to control of accidents in any mine is the establishment of a set of safety rules or operating rules. The intent of such rules is to provide guides far the workmen to follow in the operation of equipment. Frequently the workmen have no regard for such rules, and observance is obtained only through compulsion on the part of management. An interesting development in connection with-the formation of safety rules occurred during a training program for employees in the

Jan 1, 1947

By D. C. Jones

The term "coal-mine mechanization" is definable in several ways. In its general application it can mean the use of machines instead of manpower in each of the various mining activities necessary for the production of coal—so that under this definition a mine that uses mechanical coal cutters could be classed as a mechanized mine. Common usage, however, insists that a mechanized mine is one in which machines are used for the entire process of mining or extraction and transportation of the coal. For the purpose of this paper, then, the second definition of "coal-mine mechanization" will be used, and practices employed in mines where the greater part of the production is obtained through the use of mechanical loaders and conveyors will form the basis for this discussion. Physical Contact Hazards If we were to group all the hazards that accompany the use of mechanized equipment in a mine, the predominant class would be that which, for want of a better name, might be termed the "physical contact" hazards; that is, all the sources of danger that lead to accidents through physical contact of workmen with machines. A survey of accidents in a group of mechanized mines indicated that this class of hazards may be responsible for more than half the number of accidents in mechanized mining. For example, of 21 mining-machine accidents at one mine, 14 were of the physical contact type; of 14 loading-machine accidents at the same mine, 8 were the result of physical contact. Certain of these hazards are controllable through the use of guards— a guard over the cutting-machine bits when the machine is being trammed from place to place, or a chain or some similar locking device around the cutter chain, so that an accidental blow or push against the bit control will not cause the cutter chain to move. Other hazards, such as the possibility of a loader operator having his foot crushed by a crawler tread, or a brakeman being hit by a loader boom swung too far to one side while a car is being loaded, might be subject to control through the use of guard devices, but the reduction or elimination of all physical contact hazards by such methods does not appear feasible. Every accident of the physical contact type should he investigated to discover whether guards could have prevented it, but often the only way in which to combat these hazards will be through the awakened consciousness of each workman as to the danger that exists if he indulges in unsafe practices. A good approach to control of accidents in any mine is the establishment of a set of safety rules or operating rules. The intent of such rules is to provide guides far the workmen to follow in the operation of equipment. Frequently the workmen have no regard for such rules, and observance is obtained only through compulsion on the part of management. An interesting development in connection with-the formation of safety rules occurred during a training program for employees in the

Jan 1, 1947

(This list includes only those who have entered military service within the past month, or whose entry has only recently become known to us; it also includes a few names of those whose titles or assignments have been changed within the month. The last complete list was printed in Bulletin No. 131, November, 1917. A complete Honor List is maintained in the reception room at the office of the Institute:) AARONS, J. BOYD, Captain, 4th Reinforcements, 11th Infantry, Australian Imperial Force. AHBE, F. R., Captain, 33d Engineers. AMBLER, HARRY A., 30th Infantry, Camp Greene, Charlotte, N. C. ALFORD, NEWELL G., Sergeant, Headquarters 84th, 9th Division, Camp Zachary Taylor, Ky. ANDERSON, ALEXANDER, Lieutenant, Royal Garrison Artillery. ANDREWS, CLARENCE W., 1st Infantry Co., Officers' Training Camp, 83d Div., Camp Sherman.

Jan 2, 1918

By Christopher Haycocks, Michael Karmis, David G. Lundy

Roof bolting is the most common means of support in under- ground coal mines. The main advantages of this support system are the relative ease of installation and the ability to provide a stable and unobstructed work area. Roof bolts can be broadly classified into two categories, mechanical and resin bolts. Currently, about 20% of all bolts used are the resin types, and trends show an increasing popularity of these kinds. Although the reinforcing effects of resin bolts have been well demonstrated, there is, nevertheless, a considerable lack of knowledge of their interaction with the surrounding strata. To study this interaction and to further investigate the mechanisms involved in resin bolting, an instrumentation system was designed and tested in a southwestern Virginia coal mine. The instrumentation system was composed of straingaged resin bolts, convergence and differential sag stations, and a borescope. Strain gages mounted on the bolt determined axial, bending, and shear strain at several levels along the axis of the bolt. The roof movement, as measured by the convergence and differential sag readings and as observed by the borescope, correlated well with the strains registered on the bolts.

Jan 1, 1983

By Alexander Bowie

In many places throughout the Western mountain plateau regions of the United States coal beds in place have been burned over very extensive areas, the fire evidently originating on the nakedly exposed outcrop of the coal bed and gradually burning its way into the bed for considerable distances under very heavy cover. The surface evidences of the burned-out coal beds are seen in the calcined and discolored rocks overlying the places of the outcrops. The greater the mass of the burned coal the higher the results of its combustion can be seen in the overlying strata. I have noted many instances of this condition in the States of South Dakota, Wyoming, Colorado, New Mexipo, and Arizona. In the lignite fields of Dakota and Wyoming I noted stretches of level country many square miles in extent where the surface rooks were roasted and vitrified by the burning of a great bed of lignite lying nearly level and with a light cover; this is probably the most favorable natural condition for the burning out of a coal bed. The less the depth of the rock covering overlying the coal bed, the better the chance for a continuous supply of air to the fire; but when the coal bed dips heavily into the ground, or even if level, if it passes under a hill or mountain which gives the bed a heavy covering of strata, the fire has more chances of being extinguished from natural causes than in the first condition described. The distance which a crop fire may extend into a coal field is very much influenced by the dip, the thickness of the coal bed, and the nature of the rock covering immediately overlying it. In reasoning on this subject, it would seem logical to assume in the case of a coal-bed cropping at the base of a hill and dipping into it, with an extensive drainage surface above the crop line, that a crop fire would be promptly extinguished by the caving in of the overlying strata and the precipitation of the rainfall from the drainage surface above the outcrop through the breaks formed in the caving strata. This consideration would be more or less effective according to the climate of the location and the nature of the overlying strata. In a humid climate where the rainfall was heavy the water from the natural precipitation alone would probably extinguish a crop fire before it could work its way very far under cover, but in an arid climate this preventive does not seem to be effective.

Jan 1, 1915

By R. DiBella, H. Biloni, G. F. Bolling

A study of the detailed relationship between solidification substructure and microsegregation in dilute tin alloys has been continued. New observations reveal that depressions form at the solid-liquid interface not only as an initial form of segregation but throughout the range of increasing constitutional supercooling. In order to show the importance of this node formation it proves convenient to make two simplifications. Although substructure changes continuously as constitutional- supercooling increases,&apos; the following discrete stages may be used for discussion: 1) the planar solid-liquid interface; 2) ordered nodes, or depressions at the interface;&apos; 3) two-dimensional or elongated cells;3 4) regular or hexagonal cells;4 5) distorted cells, or hexagonal cells with branches;4 6) dendrites. It is also convenient to ignore observations made near grain boundaries which interact with the cellular substructure.2-4 And, it should be clearly pointed out that all singular depressions at the solid-liquid interface will be called nodes. Heretofore, the term "node" has been used without clear justification to describe both the truly isolated depression and the junction of cell walls appearing in a later stage of segregation. This usage is continued because it seems proved by the observations. Standard systematic growth of tin crystals was undertaken over a broad range of constitutional supercooling using various added solutes. Except for one or two chance observations, this research failed to reveal any appreciable range of growth conditions over which a disordered array of isolated nodes exists. Even though &apos;some finite range of random instability must exist, it is now concluded that stage one passes very rapidly to stage two. Next, after confirming that stage two passes to stage three by the elongation of isolated nodes: a reexamina-tion of stages three, four, and five followed. Standard metallography showed that pockets of higher solute concentration (for ko < 1) became more numerous in cell walls the more severe the growth conditions. These high-concentration regions must arise from depressions; however, in stage three their segregation is not distinguishable from the segregation of the nodes which join cell walls together. It seems, therefore, that the presence of nodes is causal in the formation of new cell walls, and that the mechanism by which stage three passes to stage four is initiated by nodes. If a similar reasoning is followed, the separation of stage four from stage five appears to be just a convenience that has arisen from the decanted interface observations made in the past. The present observations again show that more severe growth conditions relate directly to an increase in the number of nodes in the hexagonal cell walls. These nodes apparently serve as the origin for lines of segregation extending within the body of a cell, and can thus be assumed to represent the earliest form of branching,* as shown here in Fig. 1. The examination of stage six involved decanted-interface structures as in Fig. 2, which are similar to those considered by Rutter and Chalmers,5 Plaskett and winegard,6 and Hellawell and Herbert,7 and where distinct protrusions are each surrounded by a depressed boundary. The corresponding microsegregation behind the interface, but not far enough behind to allow a smearing of the segregation because of diffusion,4 is shown in Fig. 3. Both the shape of the decanted interface and the segregation pattern behind it

Jan 1, 1968

By Edwin B. Eckel

This paper, based on brief field examination and on data supplied by the operators, records the condition of the Italian mercury industry as of March 1945, not long after Italy&apos;s collapse. Except for the once-Italian but now Yugoslavian Idria mine near Trieste, virtually all the known mercury deposits are in the Monte Amiata district in Siena and Grosseto Provinces, 75 miles north of Rome. This district contains the Abbadia San Salvatore. the Siele. the Argus, and the Cerreto Piano mines besides numerous prospects and unproductive mines. Under pressure from Germany the principal mines were highly productive during the early part of the war, but production fell off long before its end. All of the mines were damaged in some way at the German withdrawal but by September 1944 the Abbadia had resumed production and several others were only lacking power by the early spring of 1945. The Monte Amiata district is characterized geologically by a thick series of sedimentary rocks that range from Triassic to Eocene in age . and are surmounted on Monte Amiata itself by a thick cap of extrusive trachyte. Bodies of travertine and of landslide detritus, younger than the trachyte, are rather widespread. The structure is complex and little known but most of the ore deposits seem to lie along or near a major, north-trending fault or on associated cross-fractures. Cinnabar is the only important ore mineral and clay minerals are by far the most abundant products of hydrothermal alteration. A southward increase in the amount of stibnite, relative to cinnabar, suggests horizontal zoning. The grade of ore ranges from 0.60 to 3.0 Pet and the reserves, as compared with those in American mines, are enormous. Even in the face of war-time scarcities, the mines are remarkably self-sufficient and labor is plentiful, but the costs of production are estimated to be not greatly below those of the better American mines. Notes on the principal mines, on the mining and metallurgical methods, and on the manufacture of synthetic cinnabar are included in the paper. Introduction With but few brief interludes, Spain and Italy, including the Idria mine near Trieste, which has passed from Austrian to Italian to Yugoslavian hands in the Past 3 decades, have led the world in the production of mercury, or quicksilver, for many centuries. Despite their enviable position with respect to the supplies of a metal so essential in both war and peace, there is a notable lack of up-to-date information in America on the mercury industry of either country. Duschak and Schuette&apos; and Schuettez,3 give by far the best summaries in English known to the writer, but the latest firsthand report cited by them on the Italian mines was published in 1915.&apos; Having been deeply interested in the geology and economics of mercury for several years, the writer naturally felt most fortunate in being the to obtain enough firsthand information on the Italian industry to fill at least a few of the gaps in our knowledge. The opportunity came during the war, soon after this industry, together with the rest of Italy, had capitulated to the Allies. Many of the facts presented here are thus definitely "dated," but others are of less transitory nature, and even the dated facts should be of interest in showing the strength and

Jan 1, 1949

By Edwin B. Eckel

This paper, based on brief field examination and on data supplied by the operators, records the condition of the Italian mercury industry as of March 1945, not long after Italy&apos;s collapse. Except for the once-Italian but now Yugoslavian Idria mine near Trieste, virtually all the known mercury deposits are in the Monte Amiata district in Siena and Grosseto Provinces, 75 miles north of Rome. This district contains the Abbadia San Salvatore. the Siele. the Argus, and the Cerreto Piano mines besides numerous prospects and unproductive mines. Under pressure from Germany the principal mines were highly productive during the early part of the war, but production fell off long before its end. All of the mines were damaged in some way at the German withdrawal but by September 1944 the Abbadia had resumed production and several others were only lacking power by the early spring of 1945. The Monte Amiata district is characterized geologically by a thick series of sedimentary rocks that range from Triassic to Eocene in age . and are surmounted on Monte Amiata itself by a thick cap of extrusive trachyte. Bodies of travertine and of landslide detritus, younger than the trachyte, are rather widespread. The structure is complex and little known but most of the ore deposits seem to lie along or near a major, north-trending fault or on associated cross-fractures. Cinnabar is the only important ore mineral and clay minerals are by far the most abundant products of hydrothermal alteration. A southward increase in the amount of stibnite, relative to cinnabar, suggests horizontal zoning. The grade of ore ranges from 0.60 to 3.0 Pet and the reserves, as compared with those in American mines, are enormous. Even in the face of war-time scarcities, the mines are remarkably self-sufficient and labor is plentiful, but the costs of production are estimated to be not greatly below those of the better American mines. Notes on the principal mines, on the mining and metallurgical methods, and on the manufacture of synthetic cinnabar are included in the paper. Introduction With but few brief interludes, Spain and Italy, including the Idria mine near Trieste, which has passed from Austrian to Italian to Yugoslavian hands in the Past 3 decades, have led the world in the production of mercury, or quicksilver, for many centuries. Despite their enviable position with respect to the supplies of a metal so essential in both war and peace, there is a notable lack of up-to-date information in America on the mercury industry of either country. Duschak and Schuette&apos; and Schuettez,3 give by far the best summaries in English known to the writer, but the latest firsthand report cited by them on the Italian mines was published in 1915.&apos; Having been deeply interested in the geology and economics of mercury for several years, the writer naturally felt most fortunate in being the to obtain enough firsthand information on the Italian industry to fill at least a few of the gaps in our knowledge. The opportunity came during the war, soon after this industry, together with the rest of Italy, had capitulated to the Allies. Many of the facts presented here are thus definitely "dated," but others are of less transitory nature, and even the dated facts should be of interest in showing the strength and

Jan 1, 1949

By Wm. D. Owsley, R. E. Moeller

In the petroleum industry, the process known as oil well cementing is the equivalent of pressure grouting in the mining and construction industries. The science of oil well cementing has been known and practiced for many years. At the present time it has been brought to a high degree of perfection in the handling of many different types of jobs, all of which are known as oil well cementing. In order to understand more easily these processes, we will discuss briefly several different types of oil well cementing jobs, the purposes for which they are performed, and the methods of their accomplishment. It is believed that some of .these procedures, in a modified form, can be applied to pressure grouting projects in general. Originally, oil well cementing consisted of placing a neat cement slurry about a steel casing set in a bore hole. Cement is used about these casings to protect them from the corrosive effects of ground waters, to protect the oil and gas zones from encroachment of undesired water from other levels, to prevent the blowing out of high pressure oil and gas zones from shallow levels, and to strengthen generally and support the casing being placed in the bore hole. After the bore hole is completed to the desired depth, casing is run into the well, pumps are attached to this casing and circulation of the mud fluid in the hole is established; this circulation being from the inside of the casing into the annulus about the casing, and thence back to the surface. Next, a cement slurry is mixed and pumped into the inside of the casing string, A plug, which acts as a piston within the casing, is placed above the cement slurry. This is to separate the top of the cement slurry from mud or water which is used to shove the cement down through the casing and out into the annulus. This plug further serves the purpose of shutting off against a baffle in the bottom end of the casing string, thus stopping the flow of cement out of the casing and leaving the shoe, or lower end of the casing, surrounded by cement and also filling the annulus there above. Casing strings cemented in the above described manner may vary in length from a few feet of large diameter pipe to very long lengths of smaller pipe. As of the present date the longest string of casing which has yet been cemented is some 16,600 ft deep. As a general rule, the deeper the well and the more cement slurry used, the higher the pressures which are required to place the slurry. In parts of West Texas, it is not uncommon to use 4000 sacks to cement a single string of casing in place. Machinery used to mix the cement and place it into the casing is mounted on heavy duty, powerfully equipped trucks which are capable of negotiating any type of highway or country roads. These trucks

Jan 1, 1949

By K. M. Fagin, D. W. Carter

Six new oil fields were discovered in the East and East Central Texas district during 1942. The Coke and Quitman fields, in Wood County, at this time appear to be the two most important oil discoveries for the year. The. four other oil fields discovered were Concord, in Anderson County; Kildare, in Cass County; Weiland (ClubLake), in Hunt County; and Larissa, in Cherokee County. The Rodessa lime in the Chapel Hill field, Smith County, provided the only new oil zone in older fields. The Hawkins field, Wood County, was the most active in drilling operations, 125 new wells being completed during the year. The Chapel Hill field tied the Coke field for second place with 30 completions each. The third most active field was Kildare, with 10 completions. Like the other oil-producing districts of the country, wartime restrictions reduced the number of oil and gas-well completions to 265 in 1942, compared with 964 completions in 1941. This represents a drop of 72 per cent and only a little more than one half enough to replace the 437 producing wells abandoned in the district during the year. Tn addition, the number of producing wells temporarily shut down nearly tripled, far two principal reasons: (I) the rule of the Petroleum Administration for War preventing operators from equipping more than, one well on each 10 surface acres with pumping or artificial-lift equipment, and (2) the Railroad Commission&apos;s issuance of various orders permitting the transfer of allowable for wells having high water-oil ratios and high gas-oil ratios to other wells capable of producing the same with less waste of reservoir energy. No changes were made in prices of crude oil in the district during 1942. Production and Probation The district produced 158,928,281 bbl. of oil and distillate during 1942, compared with 163,566,695 bbl. during 1941, which represents a decrease of 3 per cent. The East Texas field produced 120,680,595 bbl. of oil, compared with 130,377,793 during 1941; a reduction of 9,697,198 bbl., or 7.4 per cent. The production of this field represents 75.9 per cent of the district total, compared with the 79.7 per cent that it furnished in 1941. The district had an estimated basic daily oil allowable of 623,242 bbl. on Dec. 31, 1942. Approximately 31.8 per cent of the production in Texas during 1942 was supplied by this district, compared with 33 per cent during 1941- Changes in the annual production of newer and flush fields in this district are attributable either to a difference in the number of wells producing during the year or to changes in basic allowable and number of shutdown days due to shifting market dconditions brought on by the war. All regularly prorated fields in the district were shut down 123 days. Major exceptions were the East Texas field, closed128 days; Hawkiis, shut down 106 days; and Cayuga, Sulphur Bluff, Talco, and Rodessa, which

Jan 1, 1943

By D. W. Carter, K. M. Fagin

Six new oil fields were discovered in the East and East Central Texas district during 1942. The Coke and Quitman fields, in Wood County, at this time appear to be the two most important oil discoveries for the year. The. four other oil fields discovered were Concord, in Anderson County; Kildare, in Cass County; Weiland (ClubLake), in Hunt County; and Larissa, in Cherokee County. The Rodessa lime in the Chapel Hill field, Smith County, provided the only new oil zone in older fields. The Hawkins field, Wood County, was the most active in drilling operations, 125 new wells being completed during the year. The Chapel Hill field tied the Coke field for second place with 30 completions each. The third most active field was Kildare, with 10 completions. Like the other oil-producing districts of the country, wartime restrictions reduced the number of oil and gas-well completions to 265 in 1942, compared with 964 completions in 1941. This represents a drop of 72 per cent and only a little more than one half enough to replace the 437 producing wells abandoned in the district during the year. Tn addition, the number of producing wells temporarily shut down nearly tripled, far two principal reasons: (I) the rule of the Petroleum Administration for War preventing operators from equipping more than, one well on each 10 surface acres with pumping or artificial-lift equipment, and (2) the Railroad Commission&apos;s issuance of various orders permitting the transfer of allowable for wells having high water-oil ratios and high gas-oil ratios to other wells capable of producing the same with less waste of reservoir energy. No changes were made in prices of crude oil in the district during 1942. Production and Probation The district produced 158,928,281 bbl. of oil and distillate during 1942, compared with 163,566,695 bbl. during 1941, which represents a decrease of 3 per cent. The East Texas field produced 120,680,595 bbl. of oil, compared with 130,377,793 during 1941; a reduction of 9,697,198 bbl., or 7.4 per cent. The production of this field represents 75.9 per cent of the district total, compared with the 79.7 per cent that it furnished in 1941. The district had an estimated basic daily oil allowable of 623,242 bbl. on Dec. 31, 1942. Approximately 31.8 per cent of the production in Texas during 1942 was supplied by this district, compared with 33 per cent during 1941- Changes in the annual production of newer and flush fields in this district are attributable either to a difference in the number of wells producing during the year or to changes in basic allowable and number of shutdown days due to shifting market dconditions brought on by the war. All regularly prorated fields in the district were shut down 123 days. Major exceptions were the East Texas field, closed128 days; Hawkiis, shut down 106 days; and Cayuga, Sulphur Bluff, Talco, and Rodessa, which

Jan 1, 1943

By S. R. Balajee, I. Iwasaki

The adsorption mechanism of corn starch and its derivatives at mineral-solution interfaces was investigated by the adsorption of cationic starch, unmodified corn starch, British Gum 9084, and anionic starch on quartz and hematite. The adsorption of these starches, which decreases in the order mentioned, is dependent on the balance between the magnitude of the electrostatic interaction and the magnitude of the hydrogen bonding. There exists a critical starch concentration for both optimum flotation and flocculation conditions of iron ores, which corresponds to a point where the starch adsorption reaches a saturation coverage. Flocculation occurs due to the adsorption of starch via electrostatic and hydrogen-bonding forces and by interparticle bridging as a result of the conformation of starch molecules at the interface. The depressant property of starches and starch derivatives in flotation&apos; and their flocculation char: acteristics in clarification and filtration2.3 have long been recognized on a wide variety of ores. The effectiveness of a starch as a depressant for iron minerals has been the subject of much investigation in recent years both in the amine flotation of siliceous gangue and in the anionic flotation of activated silica from iron ores. It has been reported that the depressant activity of starches and dextrins in the cationic flotation of quartz from hematite increases with molecular weight, branching, and number of hydroxyl groups, 1 and that the selectivity is affected by changing the configuration of starch molecules and the composition of its polar groups.4 ,5 The manner in which starches are solubilized was shown to exert a significant influence as a depressant in the anionic silica flotation, and a series of articles covering the practical aspects of flotation and flocculation have already been reported.618 Chemical modification of the starch structure, the pulp pH, the calcium ion, and the residual starch concentration were identified as some of the more important variables affecting the flotation behavior. In the flocculation of iron ores, it was noted that most starches flocculated suspensions of hematite in water but did not flocculate similar suspensions of quartz,9 and that an excessive use of starch restabilized the suspensions due presumably to protective action. 6 An admirable application of such an observation to practice may be cited in the selective flocculation and desliming in the anionic silica flotation of iron ores, which resulted in superior metallurgy and lower reagent cost. 10 From detailed adsorption measurements, Schulz&apos;and Cooke4 established that the adsorption of starches and their derivatives depended on the types of minerals and of starches, pH, and electrolytes present. Their adsorption data and the foregoing flotation and flocculation observations suggested that an electrical interaction between starches and charged mineral surfaces might be playing a role in their adsorption process. Adsorption of organic polymers, particularly of synthetic origin, at solid-liquid interfaces has been extensively studied in recent years,&apos; and it is realized that their adsorption mechanism is considerably more complex than that of simple ions or molecules. A polymer molecule possesses a number of functional groups, and the adsorption at a point may restrict the adsorbability of adjacent groups. The mechanism may be further complicated by the conformation of the polymer molecules which may exist as coiled spheres, helices, or extended chains as a result of intramolecular interactions among functional groups as well as intermolecular interactions with solvent molecules. The object of the present investigation was to examine the effect of the chemical modification on the adsorption characteristics of starches and starch products on quartz and hematite at several pH values, so that by correlating this information with flocculation and flotation results, adsorption mechanism of starches on mineral-solution interface may be elucidated. EXPERIMENTAL MATERIALS Quartz: St. Peter sand was screened at 35 mesh and the undersize was scrubbed and deslimed at a Fagergren cell. The deslimed sand was cleaned with 0.1 N hot hydrochloric acid and washed repeatedly with distilled water, For anuscript, measurementsl the -200-mesh fraction of the sand was ground dry in a porcelain mill for 3 hr. The specific surface of the finely ground quartz was

Jan 1, 1970

By Elmars Ence, Harold Margolin

The titanium-aluminum system has been investigated in the composition region 0 to 34 pct Al in the temperature range 800" to 1450°C. The phases encountered in this region were: a,ß, TiAl3, The reactions observed are as follows: 13 ; L - 6T. A1, 0 (15 pct Al) + 6 (18 pct Al) - yTi Al (16.5 pct Al) at -1170°C andP (7 pctpct Al) + y (9.2 pet Al) - ah(9 pct Al) at - 1060°C. A eutectoid reaction: y — a +d belm 700°C is postulated. THE Ti-A1 system has been the sub.ect of a number of investigations. Several of these1-3 have indicated extensive solubility of A1 in both a and ß titanium. Ence and Margolin, as a result of work on the Ti-A1-0 system:&apos;5 have shown that the a solubility ofalumi-num is considerably restricted, and found that a compound, Ti2A1 existed in the region formerly designated as Q a This structure was identified as hexagonal with c/a = 0.803. Pietrokowsky confirmed the existence of this phase7 and pointed out that the structure was isomorphous with Ti3Sn.8 Although the existence of Ti,A1 has been confirmed by others,9-12 there has been considerable disagreement regarding the composition and mode of formation. A detailed reinvestigation of the Ti-A1 system has been published by Sagel et al.13 The tentative diagram indicated two phases, a, and e, occurring in the former all a region. The a, phase has the same structure as Ti2A1 and was indicated as having a broad region of solubility. Epsilon, a tetragonal phase, was shown to form within the a, solubility region. AS a result of unpublished work,14 Ence and Mugy3 olin disagreed with the interpretation of Sage1 et al., although some common features existed. The present study was conducted in an attempt to clarify prevailing uncertainties. EXPERIMENTAL PROCEDURE Alloy Preparation—Alloys were prepared from iodide titanium (99.9 pct Ti with less than 0.01 pct Zr) or Bureau of Mines electrolytic titanium (BHN-73) and high purity aluminum (99.99 pct). Alloys were arc-melted in argon or helium atmosphere as 15-g buttons in the composition range up to 34 pct Al. Depending on need, alloys were made in increments varying from 0.25 to 2 pct Al. Up to five 15-g buttons of some compositions were made. Weight losses during melting did not exceed about 1 pct of the charge and chemical analysis revealed that both titanium and aluminum were evaporated. In general, nominal and analyzed compositions agreed within 0.5 pct and therefore nominal compositions were used in plotting the data. Unavoidably, some overlap of composition occurred, particularly where small increments of A1 were used. The small increments were primarily used to obtain alloys which would fall into the narrow a -, r region and this purpose was achieved. In general, the data obtained from Bureau of Mines base titanium and iodide titanium alloys were in agreement. Forging—Both as-cast and forged samples were employed. Samples were heated for hand forging by an oxygen-hydrogen torch to the region 1200" to 1300°C. A titanium anvil and cover plate were used to prevent any iron pick-up and consequent formation of a low melting point compound. Frequent reheating kept the temperature in the desired range. Under these conditions, alloys containing up to 15.5 pct could be successfully forged. To check on the depth of contamination, forged alloys were heated slightlybelow the ß transformation temperature. Metal was removed to a depth below the contaminated surface so revealed, and the subsequent results obtained from these samples agreed closely with those secured from as-cast material. Heat Treatment—Prior to heat treatment, all alloys were vacuum annealed to remove hydrogen. Samples

Jan 1, 1962