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By X. J. Lu

Purified Na-montmorillonite samples were used as the starting materials to prepare organically modified montmorillonites (OM), and a series of OM samples were prepared by intercalation of al-kyl quaternary ammoniums with different alkyl chain length. The interlayer spacing (d001) of the OM was determined by small angle X-ray diffraction and its gelating performance was characterized by measuring the viscosity of OM/dimethylbenzene mixture. The effects of alkyl chain length, dosage of alkyl ammonium, intercalation duration and layer charge of the starting material on the OM structure and gelating properties were investigated. According to the results, the adsorption quantity of the alkyl ammonium is dependent on the hydrocarbon chain length, the dosage of the alkyl ammonium and the retention time. The adsorption quantity of the alkyl ammonium increases with the chain length and the dosage, and extra adsorption more than the CEC of the montmorillonite sample was observed under the dosages of more than 1.3 CEC. The interlayer spacing (d001) of the OM shows a dynamic variation with the dosage and the retention time, and super interlayer spacings greater than the length of the alkyl ammonium were observed under larger dosages and shorter retention times. However, the gelating performance of OM does not follow the variations of the adsorption quantity of alkyl ammonium, an optimum viscosity value of OM/ dimethylbenzene gel was observed with the moderate adsorption of the alkyl ammoniums. Furthermore, the layer charge plays an important role on the gelating performance of OM. The OM synthesized by the starting material with lower layer charge shows better gelating performance in the dimethylbenzene solution.

Jan 1, 2014

By Hisataka Sakakibara

Although the pathophysiology of vibration-induced white finger (VWF) is still under discussion, evidence has been accumulated to understand the underlying mechanism. VWF is pathophysiologically characterized by an enhanced vasospastic response to cold, which can result from an imbalance between vasoconstriction and vasodilation in the digital arteries in response to cold (i.e., vasoconstriction-dominant). The imbalance is supposed to be due to faults in vascular vessels and sympathetically mediated vascular tone. Enhanced vasospastic response to cold Narrowing of arterial lumen with medial smooth muscle hypertrophy. Possible functional factors for enhanced vasoconstriction • Increased sympathetic nervous activity to cold (e.g., norepinephrine) • Increased release of endothelin-1 (ET-1; an endothelial-dependent vasoconstrictor) from the endothelium • Increased reactivity of alpha2-adrenoreceptors to cold Possible functional factors for decreased vasodilation • Decreased release of nitric oxide (NO; an endothelial-dependent vasodilator) from the endothelium • Decreased release of calcitonin gene-related peptide (CGRP; a vasodilatory neuropeptide) from sensory afferents The question is how their interrelations or imbalances among them are Vibration and arterial damage The next question is, how does hand-arm vibration exposure induce such pathophysiological changes in VWF patients? Recent morphological evidence from animal experiments shows that vibration acceleration stress (including shear stress) and smooth muscle contraction contribute to arterial damage of smooth muscle and endothelial cells. The vibration-induced arterial damage is frequency-amplitude-dependent.

Jan 6, 2006

By Brian F. Osborne

A continuous on-line particle size analysis system for solid/liquid suspensions is described. The basic sensor utilizes a centrifugal principle to separate particles according to size, the resultant separation being measured by means of beta-ray attenuation. Results obtained when analyzing a variety of materials at sizes from 65 mesh (210 microns) to 20 microns are discussed in de- tail. Accuracies better than 2% are demonstrated. The effects of particle specific gravity, and mixtures of materials of diverse specific gravities, are discussed from a practical and theoretical viewpoint. It is demonstrated that particle specific gravity has a minimal effect on the size reading obtained. This renders the instrument suitable for handling materials where the ratio of light to heavy component may change. The design of the first commercial installation of this instrument is described in detail. This installation will be capable of analyzing three streams in sequence, measurement at three particle sizes being effected on each stream.

Jan 1, 1973

By Marius B. Wechsler

A mathematical analysis is developed for the determination of the cases when HP-piles might be replaced by precast concrete piles. The analysis focuses especially on the "integral abutment-bridges" which are used on large scale in the Great Plains of the United States of America, The theoretical considerations are illustrated by a numerical example.

Jan 1, 1992

By R. L. Grayson, L. L. Probert

"A three-year project focusing on the depth profiling of respirable coal mine dust particles using scanning electron microscopy coupled with energy dispersive X-ray analysis resulted in the development of statistically classified particle-behavior models. The models depict the changing silicon fraction for particles at 5-, 7-, 9-, and 11-keV accelerating voltages, thereby giving a clear indication of the nature of various types of mineral particles. This paper focuses on the results for respirable quartz particles sampled from five underground coal mines across the US. Through statistical analysis of results the relationship between the fraction of surface available quartz in respirable dust samples and coal rank is established for three Pennsylvania coal seams. IntroductionThis is the last in a series of papers detailing the results of SEM/EDX-based analyses of respirable coal mine dust particles collected from field sampling. Previous papers have detailed preliminary results and the statistical validity of the methodology (Grayson, Andre, and Simonyi, 1990; Grayson, 1991). This paper presents the final results of the analysis of respirable dusts from five coal seams with a range of coal rank:• Lykens Valley seam (anthracite), eastern Pennsylvania• Brookville (A) seam (mid-vol bituminous), central Pennsylvania• Pittsburgh seam (high-vol B bituminous), western Pennsylvania• No. 6 seam (high-vol C bituminous), Illinois• Wadge seam (sub-bituminous A), ColoradoSEM/EDX-based techniques were applied to try to clarify the role of quartz as an etiologic agent in coal workers' pneumoconiosis (CWP). It was hypothesized that previous studies were hampered by the restrictions of bulk analysis techniques and that particle-level analyses were needed to answer a number of questions concerning the role of quartz in CWP and its progression.Since 1985, a large number of the respirable dust samples submitted to MSHA are analyzed for free silica (Tomb, Parobeck, and Gero, 1986). Our reasearch shows that conventional bulk analysis techniques may not give a true indication of the biologically available, or active, quartz in mine dusts. Analytical evidence indicates that respirable dust samples may contain many quartz particles that are occluded, or coated, resulting in a bulk analysis for ""free silica"" that may not be indicative of the biologically available quartz surface."

Dec 1, 1996

By N. J. Grant, B. C. Giessen, U. Wolff

With the aid of the splat-cooling technique of rapid quenching, metastable alloy phases based on antimony ad bismuth have been prepared. At room temperature, simple cubic phases were found in the Sb + Au, 56 + Yd, and Sb + Ni systems. Another phase was retained in the Au-Bi system at -190°C; in this systent, a microcrystalline phase and a rhombohedrally distorted phase were also observed. The crystal chemistry of these phases is discussed in terms of their valence electron concentration range. A remarkable five-step Phase sequence was found upon heating and equilibration of certain metastable Au-Bi alloys. USING the splat- cooling technique of rapid quenching from the liquid,' a large number of metastable intermediate alloy phases have been prepared in recent years. Thus, Hume-Rothery phases of the hexagonal type based on the valence electron concentration have been produced in systems where they are missing in equilibrium, e.g., Ag-Ge 1 or AU-Sb. 3 In a comprehensive study of metastable alloys based on tin, simple hexagonal metastable y phases were found, raising the total of stable and metastable y phases from 3 to 13. 4 In the In-Bi system, five new metastable intermediate phases were retained.' In most cases, the new metastable phases have some crystal chemical characteristics in common: a) They have rather simple, elementlike structures with few atoms per unit cell, e.g., y phase,4'5 or the metastable primitive cubic phases in the Ag-Te and and Au-Te systems.= b) Their structures are often related to those of the terminal phases, or to elements that are straddled in their position in the periodic table by the constituent elements; this is the case for metastable ß (In-Bi) with the structure of white ß Sn,' or metastable a (Cd-sn). 4 c) They seem to represent the crystal structures appropriate to certain average group number (AGN) ranges in which no or few single-phase structures exist in equilibrium. These average group number ranges can probably be equated in the case of many elements of the Ba(Zn)-Bs(As) groups with the averaged valence electron concentration. In the present work, the splat-cooling technique has been applied to the alloys of antimony and bismuth. In equilibrium, neither element forms intermediate alloy phases with other B elements from groups Bl(Cu) to B4(Si) that contain more than 66.7 at. pct of Sb or Bi, respectively, e.g., AUSb 2. 7 Thus, antimony- or bismuth-rich phases, which might be closely related to antimony or bismuth, and which would reflect struc- tural changes occurring on alloying with small amounts of addition elements, do not exist. Also, the terminal solubility of antimony and bismuth for all B metals is very small. It was therefore of interest to investigate the influence of enforced, nonequilibrium solid solution of addition elements in antimony and bismuth on their crystal structures. It was found that additions of group B 2-B4 metals act distinctly differently than additions of group T 10 and B1 metals. The latter set of additives will be treated here. EXPERIMENTAL TECHNIQUES Alloy preparation and splat-quenching followed closely the procedures described in Refs. 1, 4, and 5; they consisted of the preparation of master alloys from high-purity starting materials (99.99+ pct) and blast-atomizing of 20-mg quantities onto copper sheets. The resulting approximately 1 to 5 u thick foils were investigated by X-ray diffraction. The cooling rates obtained are of the order of 107 to 10 8 C per set,'" causing solidification to proceed at a rat; of approximately 100 cm per sec.' Powder patterns of the resulting fine-crystalline materials were taken with filtered CuK, radiation. For antimony alloys the substrates were held at room temperature and for bismuth alloys at -190°C both during splat foil deposition and X-ray investigation. Annealing treatments at several

Jan 1, 1969

By T. Kilner, A. Plumtree

DURING an investigation of electro-deposited silver structures, samples were prepared for metallographic examination by cold mounting in plastic, grinding on successive grades of emery paper down to 3/0, and chemically polishing by swabbing using the chromic acid solution described by Gilpin and Worzala.1 Attempts to etch these samples using the standard solutions described for silver (e.g., 5 pet KCN-5 pet Na2S2O8, H2O2-NH4OH, and various potassium dichro-mate solutions) all failed to give good results due to staining of the samples and to rapid etching. The staining was caused by the chromic acid polishing solution being trapped in small fissures between the sample and the mounting plastic, and also in small fissures in the sample itself. To overcome these difficulties, an etchant was developed which prevented staining at the same time as it slowly etched the sample. This resulted in a very clean, crisply etched surface as shown in Figs. 1 and 2. This etch consisted of 10 ml of orthophosphoric acid, 10 ml of distilled water, and 2 drops of the polishing solution noted above,' which is made by mixing 100 ml of saturated CrO3 solution, 45 ml of 10 pet HC1 solution, and 800 ml of distilled water. The etching procedure involved taking the final polished sample, either immersing or swabbing in the etchant for a period of 1 to 2 min, rinsing as quickly as possible in distilled water, alcohol, and ethyl ether in that order, and then immediately drying. This etch is easily controlled due to its slow rate of etching, and produces samples with clean, sharp surfaces. Pits due to overetching produced varying contrast effects when viewed under polarized light, and are therefore obviously useful for revealing many structural details within the sample. Another effect of overetching was to produce a height varia-

Jan 1, 1968

By D. E. Poole

Injury Prevention: Dependent, Independent and Interdependent In recent years, management-directed (dependent)safety programs have lost ground to the more successful self-directed (independent) programs, where employees take responsibility for their own safety. Today, with the growth of the team concept in industry, a mutual-caring (interdependent) approach to workplace safety is gaining wide acceptance. This presentation compares characteristics and results of the three progressive levels of safety responsibility and explains how to develop a successful interdependent program. The presentation will also detail the common principals that are necessary for safety excellence under any of the management styles.

Jan 1, 2000

By John H. Hollomon

THE interpretation of notched-bar impact results has been a matter of controversy since the introduction of more or less standard tests by Fremont,1 Charpy2 and others at the turn of the century. Many investigators3-l1 have contributed to the understanding of the significance of such tests. Several symposiums12,13 have been held with the express purpose of discussing the significance and interpretation of the impact tests. It is not the purpose of this paper to review all these contributions to the development of the knowledge on this subject, but rather to present an interpretation of notched-bar impact tests that appears to be in agreement with the available published data. Fundamentally, the interpretation discussed in this DaDer of the brittle failure of some steels in notched-bar impact test is similar to the qualitative analysis presented by Ludwik3 in the 1920's. Essentially, Ludwik stated that the function of the notch was to increase the tensile stress necessary for yielding, and that brittle failure occurred when the stress necessary for yielding exceeded the normal stress required for fracture (with no plastic de- formation). Ludwik, however, had no means of measuring this normal stress necessary for failure of a plastically* undeformed metal, therefore he could not extend his interpretation beyond the qualitative stage. Kuntze14 and recently MC- Adam15 attempted to determine the effect of deformation on the stress necessary for fracture by testing, in tension, specimens notched to various depths and angles. Because of the uncertainties in Kuntze's (and RlcAdam's) analysis of the stresses (which have been pointed out by SachsI6) and the inherent nonuniformity in the stress distribution in notched bars, the results of such investigations are difficult to interpret. A more direct method of measuring the effect of deformation on the fracture stress was suggested in previous papers17-l8 and has been utilized in the present investigation. The present paper concerns itself primarily with the behavior of notched impact specimens. The effects of strain rate, temperature, and stress distribution, which are discussed with reference to the impact specimen, apply just as well to the behavior of metal at the bases of notches in any engineering structure. All that is necessary is to determine the stress distribution in the structure at the base of the notches.

Jan 1, 1944

By Kenneth S. Johnson

Western Oklahoma, with an estimated 48 billion tons of minable gypsum, has one of the largest reserves of high-purity stone in the United States (Figure 1). Gypsum beds of the Permian Blaine Forma¬tion are 10 to 30 feet thick in the southwest and northwest regions, and the Permian Cloud Chief Gypsum is 20 to 90 feet thick in the west-central region (Ham, 1962; Ham and Curtis, 1958; Scott and Ham, 1957). Republic Gypsum Company, in the southwest part of the State, is Oklahoma's second-largest gypsum producer. Since opening its plant in 1964, the company has steadily increased production and now accounts for about 15 percent of the State's annual output. The plant and quarry are 15 miles west of Altus at Duke, a small commu¬nity on the Hollis and Eastern Railroad in northwestern Jackson County.

Jan 1, 1970

By B. W. Roberts, V. A. Phillips

A copper alloy containing- 25.5 at, pct Zn and 19.0 at. pct Ni, which was previously found to show an anoma1old.s hardening effect on quenching- from 600 "C and aging- at 400oc, has now been examined by neutron diffraction. No evidence of long-range order was found. The aged sample showed diffuse scattering- consistent with clustering. The anomalous hardening effect is now attributed to lattice strains caused by clustering rather than (long-range) order hardening. SOLID-solution Cu-Ni-Zn alloys (the commercial 'nickel silvers") have been reported to show anomalies in: change of resistivity on cold working,1-6 temperature coefficient of resistance,2-12 resistivity at low temperatures,13,14 parameter (vs temperature),2"4 calorimetric data,2,4 specific heat,15,16 dilation,2-4 and elastic modulus.17 The structure responsible for the anomalies is produced by annealing typically near 400°C and is rather loosely referred to as the ('K-Zustands" (K state), a term coined by Thomas1' who apparently meant simply that the arrangement of atoms on the sites deviated from that expected statistically. Thomas proposed that the K state occurred in a variety of (solid-solution) alloys such as Cu-Ni-Zn, Ni-Cr, Ni-A1, Ni-Cu, Fe-A1, and Fe-Si and is recognized because its formation is strongly temperature-dependent and results in an increase in electrical resistance which can then be decreased by cold working. Later workers on ('nickel silver" have interpreted the K state variously as short-range order, long-range order. or a combination. The present work was prompted by the discovery by Phillips and Jones19 of a substantial hardening effect when an 18 pct "nickel silver" alloy which is fairly close to the Cu2NiZn composition, was reheated in the range 150" to 450 C after previously quenching from 600°C or, alternatively. was slow-cooled from 600°C or above. The phenomenon was attributed to (long-range) order hardening. Due to the similarity in the atomic scattering factors of copper. nickel, and zinc atoms, the ''nickel silvers" are unfavorable for X-ray diffraction studies aimed at detecting ordering. Nevertheless Bialas et a1.,20 using a powder sample containing 47.96 wt pct Cu, 24.03 wt pct Ni, and 27.98 wt pct Zn, slow-cooled from 400" to 200°C taking 500 hr, observed weak super lattice lines. Further unpublished work" using an anomalous dispersion X-ray technique indicates that zinc atoms are regularly ordered at the corner points of the lattice cell, while the nickel and copper atoms are statistically distributed on the remaining sites. Köster 17 also observed X-ray superlattice lines, for example, in an alloy containing 43.5 wt pct Cu, 28.6 wt pct Ni, and 27.9 wt pct Zn superimposed on the basic fcc cell with a = 3.62 kX. He proposed a Cu3Au-type superlattice with the Ll2 structure in which the A sites were statistically occupied by copper and nickel atoms and the B sites by zinc. He adds that substitution must be possible so that zinc atoms partly occupy A sites. Below about 35 pct Cu, Koster had some evidence for a CuAu-type superlattice with the Llo tetragonal fcc structure with a = 3.82 kX, c/a = 0.88 which could be preserved by quenching. This is suggested17722 to correspond to CuNiZn. While the present work was in progress Hirabaya-shi et a1.23 made an independent comprehensive neutron-diffraction study of a single crystal containing 50.05 at. pct Cu, 26.57 at. pct Ni, 0.25 at. pct Mn, 0.13 at. pct Fe, balance zinc. The presence of manganese and iron is surprising since the crystal was supposedly grown from high-purity metals. The homogenized crystal showed evidence of long-range ordering after an anneal of 5 months at about 300°C. Three possible crystal models were proposed. A curious feature of their results23 is that they could not find any neutron-diffraction evidence of ordering in a powdered polycrystalline near-stoichiometric Cu2NiZn alloy. There appears to be some essential difference between a near-stoichiometric Cu2NiZn alloy and one somewhat further off stoichiometry as used by the present authors. Thus Sato14 was able to reproduce the low-temperature resistivity anomaly reported by one of the authors13 on the present alloy if he used a similar composition, but found the normal behavior of the residual resistivity in a near-stoichiometric alloy. satol2 found that the resistivity of a cold-drawn slightly off-stoichiometric alloy increased to a maximum on isothermally annealing at 300°C and then decreased ("over-aged"). Since he could not explain this on the basis of ordering phenomenon, he proposed that zinc atoms were segregating to stacking faults (Suzuki effect) and found etching bands on the surface by replication which were attributed to the widening of faults. Sato suggested14 that the hardening effect observed by Phillips and Jones19 is partly due to the Suzuki effect. EXPERIMENTAL The starting material was 1/4-in.-diam hard-drawn rod of a commercial 18 pct "nickel silver" alloy identical with that used in a previous study by Phillips

Jan 1, 1967

By Cristiano Devitte

O presente trabalho busca verificar a viabilidade técnica de utilização de aços com diferentes percentuais de elementos de liga em sua composição química para a fabricação de brocas DIN 338, com e sem revestimento PVD de TiN comparando com aço AISI M2. A caracterização do material foi realizada em conformidade com a norma SEP 1615 e a identificação do tamanho de grão foi realizada pelo método Snyder-Graff. No teste de furação foi utilizada um centro de usinagem vertical 3 eixos. A aderência do filme PVD foi verificada pelo teste de indentação VDI 3198. As variáveis significativas foram o material do substrato, o revestimento da ferramenta, a velocidade de corte e o avanço de corte. As variáveis de resposta analisadas foram o desgaste da ferramenta, o número de furos produzidos, a rugosidade superficial e o diâmetro dos furos. Ao final do trabalho foi possível constatar que o material Z2 ainda não pode ser utilizado como alternativa ao AISI M2 para a fabricação de brocas helicoidais de aço rápido.

Aug 7, 2018

A coal mine located in southern West Virginia recently set a world record for daily low-seam coal production using a Cat automated longwall plow system. In a 24-hour period on April 10 and 11, 2014, the Pinnacle Mine longwall produced 32,411 t (35,724 st) from the Virginia Pocahontas No. 3 Seam, in a seam height of just 1.42 m (56 in.) along the 298-m (980-ft) longwall face. The Pinnacle Mine, located near the town of Pineville and owned by Cliffs Natural Resources Inc., an international mining and resource company, operates a Cat Gleithobel GH1600 Longwall Plow System. A previous record was set by this system at Pinnacle in August, 2012 when 29,423 t (32,430 st) were mined in a 24-hour period. The record was set by the same system, mining its second panel after a comprehensive rebuild was performed by Carter Machinery, the Cat Dealer in that area. The rebuild encompassed a complete rebuild of the headgate and tailgate armored face conveyor (AFC) drive, the headgate and tailgate special AFC pans, the stageloader drives and return end, the complete crusher and all gearboxes for the plow, AFC and stageloader. Carter acquired the rights to sales and aftermarket support associated with the former Bucyrus mining products, both surface and underground, in 2013. ?Supporting and rebuilding a longwall plow system was a new experience for the Carter service team,? said Chris Curfman, president of Caterpillar Global Mining Sales and Support Division. ?However, given the record production results attained by the rebuilt system at Pinnacle, it?s obvious that they are up to the challenge of supporting the underground product lines at the same high standards and quality level that they have been delivering for many years on the traditional Cat surface mining products.? Tom Bluth, president of Caterpillar Global Mining Products Division, said, ?Caterpillar congratulates the Pinnacle team for this great achievement. Without their efforts and dedication this record would not have been possible. To safely deliver that kind of output from such a thin seam is remarkable. We have been privileged to work alongside their team to demonstrate the capabilities of Cat longwall mining technology. ?

By A. D. Engelbrecht

An investigation was undertaken to ascertain the suitability of four selected low grade, South African coals for gasification in a bubbling fluidized bed for production of synthesis gas and for the development of integrated gasification combined cycles (IGCC). This study consisted of the characterization of the coals, laboratory evaluation of intrinsic reactivity, and experimentation with a pilot-plant fluidized bed gasifier. Results of the characterization experiments show that the selected coals are high in ash, rich in inertinites, very dense (low porosity), with low caking indices and high ash fusion temperatures. Reactivity measurements with a thermogravimetric analyser (TGA), under reaction rate controlling conditions with carbon dioxide, showed that the reactivity of the coal chars decreases with increase in rank of the coal, as expressed by the vitrinite random reflectance and carbon content of the parent coals. The fixed carbon conversion achieved in the fluidized bed gasifier also correlates well with the rank parameter of the coal, with higher conversions being obtained with the lower rank coals. Thermal shattering and attrition of the coal particles produce significant amounts of fines, which correlate with the grindability indices, and no agglomeration (non-caking) was observed. It is concluded that fluidized bed gasifiers are able to utilize typical low grade, high ash South African coals for synthesis gas production and for inclusion in integrated gasification combined cycles for power generation.

Jan 1, 2010

By A. A. Smith, J. S. Smart

THe elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses. When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range o to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorilv determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing 2nd oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B, and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold. The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300' and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type. All samples were quenched from the annealing temperature in 10 per cent H²S04 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.' Effect of Silver Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By A. A. Smith, J. S. Smart

THe elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses. When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range o to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorilv determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing 2nd oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B, and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold. The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300' and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type. All samples were quenched from the annealing temperature in 10 per cent H²S04 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.' Effect of Silver Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By L. D. Mullins, H. B. Bradley

Numerous articles have appeared in the literature citing the application of the potentiometric analyzer to cycling operations. Specific information obtainable by a potentiometric analysis, as noted by various investigators, includes: 1. Pattern sweep efficiency for various injection and production rate programs. 2. Injected fluid breakthrough time at production wells. 3. Optimum production and injection rates. 4. Prediction of injection and/or production well locations. 5. History of advance of the in-jected-produced fluid interface. 6. Ultimate life of the reservoir. 7. Ultimate reservoir production. This note describes a procedure for predicting pressure distribution in a gas-condensate reservoir by using the potentiometric analyzer to obtain potential distribution data on an analog model of the reservoir and then applying Muskat's' equations. The method relates the volumetric weighted average datum pressure to the mean potential in the model.

Jan 1, 1958

By Shu Yamaguchi

The behavior of halide impurities in pyrometallurgical processes such as Wealtz kiln and MF process has been discussed based on the thermochemical data and the reported data of PbO activity in PbCl2-PbO melts. The role of PbCl(g) has been estimated to be significant in the chloridization evaporation reaction. From reported data on the PbO activity in PbC12-PbO melts, activity of PbCl2 has been calculated by the numerical integration of Gibbs-Duhem equation, and the stability domains and the composition of the liquid phase as well as the vapor pressure of PbCl2 have been estimated as functions of log P2HCI/PH2O and temperature. From the discussion of the path during cooling process on the log P2 HCI . PH2O vs. temperature diagram, the authors proposed a possible dechioridization process that utilize water vapor as a dechloridizer for the direct precipitation of PbO from gas phase.

Jan 1, 2003

By A. C. Watts

The question of disposition of the slack and dust so troublesome to coal mine operators of the West has been divided by your committee chairman into three heads, viz: The preparation and transportation of fine and powdered coal. The developments along the line of low heat carbonization. The uses to which fine and pulverized coal have been put. The development of low heat carbonization has been assigned to me. This is really not a part of the subject but as it has a most important bearing on the future use of coal, I presume the chairman thought best to include it. An English committee on smoke abatement makes the statement that the burning of raw coal is "dirty, wasteful and unscientific". I will go a step further and characterize it as an "economic crime." It has been predicted by eminent scientific men that eventually no raw coal will be burned for heat or power purposes. All this will take time, experimentation and large expenditure, but it will surely come. The question of disposition of slack and dust so troublesome to coal and utilization of its by-products has been retarded by the abundance and cheapness of the raw coal, and by the abundance of suitable coking coals for metallurgical purposes. But necessity is surely, if slowly, demanding that the enormous waste ensuing from the burning of raw coal for heat and power must cease. For instance, smoke abatement investigations in Manchester, England, showed that the increased cost of household washing was about $1,250,000 per year due to smoke and soot. It is estimated that in London 200 tons of soot and smoke particles are suspended in the atmosphere over that city during dense fogs and that much more than this is emitted from the chimneys each winter day during the forenoon. As an example of what benefits a smokeless fuel gives, it is cited that in the mill town of Shaw, England, the burning of smokeless fuels in the factories has reduced the so-called fogs by about 80%. Necessity, caused by the war led Germany into the field of low tem¬perature carbonization because of the shortage of motor fuel and lubricating

Jan 1, 1922

By Greg Plutko

Laboratory testing has shown that the Marsh Funnel test can be significantly impacted by long-chain polymer entanglement. In general, shorter hydration time leads to more chain entanglement which in-turn, leads to higher marsh funnel values that values seen for longer mixing. This trend makes it very difficult to predict funnel-viscosity on successive days. Data is presented which helps to explain this chain interaction effect on Marsh Funnel data and how it differs from traditional Fann viscosity. The data suggest that this long-chain polymer entanglement occurs more in samples with less hydration time and decreases as hydration time increases. There is also suggestion that higher polymer concentrations have a greater drop-off in marsh funnel viscosity for a given aging length than do lower solids slurries. Fann rheology was shown to be much less impacted by the hydration time of the PHPA polymers than was Marsh Funnel viscosity. This suggests that the Marsh Funnel viscosity is impacted by some aspect of the slurry that does not affect Fann rheology as strongly. It is known from literature that longer-chained polymers have more potential to entangle and our data support the theory that the Marsh funnel viscosity is greatly impacted by this polymer-chain ‘roping’ entanglement.