Search Documents

By M. O. Pekguleryuz, D. S. Aydin

The high temperature oxidation and ignition resistance of Mg-(0-6) wt% Nd alloys have been investigated via isothermal and continuous heating experiments conducted in air atmosphere. Alloy composition is observed to be effective in low levels (~ 0.5 %) in the ignition temperature (Ti) of the alloys; the Ti of pure Mg increased from 630 °C to 770 °C with 0.5 wt% Nd addition. However, no noteworthy improvement was achieved with further additions up to 6 wt% Nd. The initial microstructure was observed to determine the oxide structure on the surface due to the differing oxidation behavior of the phases (a-Mg + Mg12Nd intermetallics). It has been found that the formation of a Nd-depleted region at the subsurface due to extensive Nd oxidation at the oxide/intermetallic interface lowers the protective ability of the oxide scale.

Jan 1, 2015

By Samir Kumar Pal, Rajasekar Rathanasamy, Gobinath Velu Kaliyannan, Moganapriya Chinnasamy, Sathish Kumar Palaniappan

The research examines the performance of uncoated and coated tungsten carbide-cobalt rock cutting bits. It aims to optimize process variables (cutting speed, depth, coating material) considering multiple output responses (cutting forces, specific energy, wear rate, material removed, angle of reaction forces). The study uses a hybrid optimization technique combining Taguchi design, grey relational analysis, and fuzzy logic. The optimal parameter combination was found to be cutting speed: 200 mm/s, cutting depth: 6 mm, and titanium aluminum silicon nitride coating.

Apr 24, 2022

By R. Barany

The heats of formation of goethite, ferrous vanadate, and manganese molybdate at 298.15° K were determined by solution calorimetry. For formation from the elements, the heat values were -133.7 ±0.3 kcal/mole for goethite, -453.8 ±0.5 kcal/mole for ferrous vanadate, and -284.8 ±0.2 kcal/mole for manganese molybdate. For formation from the oxides, the heat values were -0.9 ±0.1 kca1/mole for goethite, -19.4 ±0.3 kca1/mole for ferrous vanadate, and -14.6 ±O.l kcal/mole for manganese molybdate.

Jan 1, 1965

By G. G. Krishna Murthy

Several experiments were conducted to determine the rates of heat transfer coefficients of CaO-SiO2-A1203-FeO slags at temperatures in the range 1623-1823 K The experimental technique involved measuring heating rates of a solid specimen, sub¬merged in slag phase, using a temperature probe made of Pt\ 10%Rh-Pt. Effect of %FeO (3-10%), %FeS (0.1-0.68%), %P205 (0.2-3.0%), %MgO(5-6%), and %MnO (0.96-3.84%) present in the slag on overall heat transfer coefficient, U, of slags was investigated. Simple first order heat balance equation in combination with experimental plots rising temperature of solid specimen versus time were employed to determine the values of U. The values of U determined in the present investigation were present in the range of 70-260 cal/Ks.m2. The value of U increased with increasing the slag temperature. The values of U were not effected by increased amounts of sulfur in the slag phase. The increased concentrations of MgO, FeO, MnO, and P205 in the slag phase decreased the values of U. On the other hand, the increased amounts of Fe2O3 in the slag phase increased the value of U. Comparison of the results, obtained using the slag bath stirred by argon injection, with those determined without any stirring indicated that both radiative and conductive heat transfer mechanisms are important even at high temperatures.

Jan 1, 1993

By José Luis Calderón

En los tres anexos (Pueblo Nuevo, Zarumilla y Chuquitambo) del área de influencia directa (AID) de Compañía Minera Poderosa se ha institucionalizado y formalizado una nueva gestión del agua de consumo poblacional, lo que ha permitido prevenir conflictos socioambientales y mantener la estabilidad social que posibilita el normal desarrollo de las operaciones mineras en el distrito de Pataz, región La Libertad.

Jul 30, 2019

(Members are urged to send in for this column any notes of interest; concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period Nov. .10, 19 16 to Dec. 1.0, 1916: Chester Atkinson, La Fundicion, Peru. , Paul Llewellyn, East Chicago, Ind. F. J. Brule, Toronto, Ont., Canada. Harry March, London, England. Sterling H. Bunnell, New York, N. Y. E. P. Mathewson, Toronto, Ont., Canada. G. H. Cunningham, Hobart, Tasmania.' E. W. Moore, Budapest, Rumania. Courtenay DeKalb, Tucson, Ariz. W. J. Pentland, Guadalajara, Mex., E. H. Dickenson, New Y.. Heinrich Ries, Ithaca, N. Y. E. B. Durham, Mount Kisco, N. Y. W. E. Saunders, Philadelphia, Pa. L. B. Eames, Pueblo. Colo. J. G. Scrugham, Reno, Nev. N: H. Emmons, 2d, Copperhill, Tens. - W. H, Seagrave, Kennecott, .Alaska. R. E. Hoffman, Hannibal Mo.'s H. B. Small, Magangue, Colombia. B. B. Hood, Chronic, N. J. W. H. Staver, Washington, D. C. H. E. Jackman, Rochester, N. Y. R. K. Stockwell, Santiago, Chile. F. H. Jackson, Joplin, Mo. Warren D. Thompson, Boston, Mass. Knight S. Jordan, Provo. Utah. Thor Warner, Kingman, Ariz. William Kelly, Vulcan, Mich. S. T. Wellman, Cleveland, Ohio. W. H. Lanagan, San Francisco. Cal. F. H. Willcox, Pittsburgh, Pa. H. H. Lauer, Northampton, Pa. Arthur K. Adams has been appointed geologist to the Andes Copper Co.

Jan 1, 1917

By Erle I. Shobert

In the comparison and consideration of synthetic and natural materials, graphites represent a situation in which natural graphites amount to less than 10% of the total carbon and graphite production by weight, and less than 5% in dollar volume, There are few applications where it could not be re- placed by synthetic graphite. On the contrary, synthetic graphite materials can be engineered to cover an extremely wide range of applications. These include electrographite brushes for rotating machinery, pyrolytic graphite, graphite-impervious pipe, nuclear moderators, high purity spectrographic graphite, power tube anodes, graphite rotary shaft seals, and rocket nozzles. The special qualities of natural graphite and its limitations are delineated and the almost unlimited possibilities in artificial graphite materials are discussed.

Jan 1, 1964

By Theodore Simons

The rapid and comparatively recent development of flotation has opened so fascinating a field for study and research that the older processes of gravity concentration no longer receive the attention they deserve. The early work of Munroel and Richards12 and the more recent contributions by Clevenger and Coe,3 Laist and Wiggin,4 Ammon,5 Bardwell,6 Crowfoot,' and Hayden8 (to mention only some which have appeared in our own Transactions) and by Schu1z,9 have furnished so much data that to offer something new seems a difficult task. It is still possible, however, to present known facts from a different point of view, and, with this in mind, the writer has undertaken to express basic principles of gravity concentration in terms of simple mathematics and mechanics; the conclusions thus reached will be found to correspond, in general, with those obtained by experimental methods. Rittinger, in his classic Aufbereitungskunde (1867)) reached analogous conclusions by way of intricate higher mathematics, for which reason his interesting investigations have remained a sealed book to most of us. The writer hopes that a more elementary treatment of the subject, based in part on Rittinger's metheds, may arouse new interest in the study of basic principles.

Jan 1, 1923

By Theodore Simons

The rapid and comparatively recent development of flotation has opened so fascinating a field for study and research that the older processes of gravity concentration no longer receive the attention they deserve. The early work of Munroel and Richards12 and the more recent contributions by Clevenger and Coe,3 Laist and Wiggin,4 Ammon,5 Bardwell,6 Crowfoot,' and Hayden8 (to mention only some which have appeared in our own Transactions) and by Schu1z,9 have furnished so much data that to offer something new seems a difficult task. It is still possible, however, to present known facts from a different point of view, and, with this in mind, the writer has undertaken to express basic principles of gravity concentration in terms of simple mathematics and mechanics; the conclusions thus reached will be found to correspond, in general, with those obtained by experimental methods. Rittinger, in his classic Aufbereitungskunde (1867)) reached analogous conclusions by way of intricate higher mathematics, for which reason his interesting investigations have remained a sealed book to most of us. The writer hopes that a more elementary treatment of the subject, based in part on Rittinger's metheds, may arouse new interest in the study of basic principles.

Jan 1, 1923

By A Fern, A Hawkes, o, T Vincent

The modern workplace has changed dramatically in recent years with an increased emphasis on the psychological well-being of employees. While adhering to a certain standard of psychosocial safety at work is now not only a moral, but legal obligation in Australia, it begs the question: how can organisations begin to ensure psychosocial safety? A positive psychosocial safety climate is one where employees feel they are psychologically safe, feel supported in their work and are not exposed to work-related stressors that can negatively affect their mental health. Such a climate can help boost productivity and create a more positive working environment. This presentation will provide a twopronged approach to understanding and managing psychosocial safety: pairing a traditional risk assessment with climate measurement. Risk assessments can provide several benefits, including identifying and characterising work-related hazards, identifying the nature and severity of the risks to employees and prioritising necessary interventions for reducing or preventing psychosocial harm in the workplace. However, these assessments can have certain limitations, especially when it comes to capturing some of the less obvious causes of psychosocial harm. Climate measurement can provide valuable insights into employees’ perceptions of the work environment, identify areas of concern that may not have been identified in the risk assessment and help to guide organisational changes that will enhance employees’ psychosocial well-being over time. It will also be argued that climate should be assessed from a broad perspective exploring general, physical, social and psychological aspects of safety climate. This presentation will explore why conducting risk assessments in conjunction with detailed climate measurements is integral to protecting the psychosocial safety of employees in the workplace and demonstrate why employers should view the two approaches as complementary and interconnected. Best practice recommendations will be provided for the risk assessment, climate measurement and psychosocial interventions

Apr 16, 2024

Carbon sequestration in planted forests provides an immediately available, low cost option to address the greenhouse impacts of coal mining and coal utilisation in a carbon constrained world. In addition, planted forests also offer the opportunity to address other environmental issues, particularly salinity and loss of biodiversity. Given salinity is characteristically associated with agriculture in the 500 to 700 mm rainfall belt, then where such forests can also produce commercial timber products, they offer the additional opportunity to establish new, diversified rural employment in both timber growing and processing. In the majority of Australian catchments affected by salinity, where rainfall is generally less than the 700 mm limit to conventional forestry, and where groundwater reserves are often saline, the objective of achieving economically viable forestry production presents a significant challenge. In 1996, Saltgrow commenced a collaborative breeding program to combine the salt and stress tolerance of E camaldulensis, with the growth rate, stem form and wood properties of the commercial species, E grandis and E globules. This program aimed to produce trees with the potential for commercial rehabilitation of saline landscapes. Results covering a range of site conditions from SaltgrowÆs network of over 100 trials around Australia are presented. The opportunity for commercial plantations integrated with agriculture in low to medium rainfall areas to address salinity and sustainability will be discussed. In addition, the significant potential for partnerships between land-rich, cash-poor farmers, catchment management authorities seeking to invest in public good projects that enhance environmental sustainability, and major carbon producing industries with either mandated or voluntary requirements to curtail net emissions will also be discussed.

Jan 1, 2005

By William Brewster

DATING back some five years ago, various foundries made inquiries as to the probable total carbon content in a given specification and grade of pig iron. Up to that time we had no data, and except for a few occasional determinations of total carbon, no attempt had ever been made to set up routine determinations of total carbon. In fact, at that time, a cast analysis was considered sufficient, without examining at further length into possible variations of analysis between ladles of the same cast. In view of the various inquiries as to total carbon, we sampled all piles of all grades of pig iron, making complete analyses. Finding some variation in carbon content, we secured more samples and plotted the carbon content with respect to silicon in each grade of iron except for the higher phosphorus foundry iron, where it was necessary to divide the group into twenty-point phosphorus ranges. This is easily understood, owing to the falling off of carbon content with the increase in phosphorus con-tent, silicon in each case being the same. In addition, these curves clearly demonstrate the lowering of the carbon content as the silicon is increased. In order to insure accuracy and reliable determinations the following method of sampling and analysis was employed: Two pigs selected from each end of the car, each car containing iron from one 50-ton ladle, are drilled with a 5/16-in. drill all the way through from top to bottom in the center of one section of the pig. The drillings are collected and transferred to an 80-mesh sieve; the portion passing through and the portion retained are placed in separate envelopes and labeled accordingly. The amount of sample in each envelope is weighed to obtain the proportionate amount of coarse and fine drillings, then a factor weight of sample (1.3636 grams) made up of proportionate

Jan 1, 1936

By H. H. Wang

Construction safety documents regulate significant safety actions and requirements by which construction workers or employees should abide in order to secure them from occupational hazard events. Therefore, facilitating faster identification of applicable safety requirements from the documents has become an important topic in the construction safety domain. To address the need in this regard, tools and techniques have been developed and research efforts have been made. One of the research efforts is to utilize ontology, a knowledge representation and reasoning approach, as the methodology to achieve the goal of identifying applicable safety requirements. In such ontology-based researches, the development and construction of the safety concept ontology is an essential task as the concepts and the relationships between the concepts both representing key safety knowledge need to be carefully identified. In this paper, the author focuses on the safety documents without predefined concept structure and aims to address the concept and relationship identification difficulties. Specifically, the author leverages the Formal Concept Analysis (FCA) methodology, a theory of data analysis that identifies conceptual structures among data sets, to mine and analyze the documents in order to discover safety concept structure and to further assist the development of the concept ontology for the construction safety documents. The author expects the application of FCA to construction safety domain can eventually benefit the ontology-based approaches for identification of applicable safety requirements.

Aug 1, 2013

By Thomas M. Drown, P. W. Shimer

THE precipitation of phosphoric with titanic acid, by boiling an iron solution which had been reduced to the ferrous condition by sulphuretted hydrogen or sulphurous acid, was first noticed by E. H. Bogardus in 1874.* Since that time, as far as we are aware, not much has been published on the relation- of these two acids to each other, and to silicic acid, in the ordinary course of analysis of iron ores. The following investigation may perhaps aid in clearing up some of the obscure points in the analysis of titaniferous ores. THE DETERMINATION OP PHOSPHORUS. From two to five grams of the finely powdered ore are weighed into a beaker and treated with about 50 c.c. of hydrochloric acid (sp. gr. 1.12), evaporated to dryness, and heated in an air-bath for * American Journal of Science, III, 8, p. 334.

Jan 1, 1882

By SANJIT KUMAR PAL, Sarvesh Kumar, Arindam Guha

The integrated geophysical study around pipe 1 and pipe 2 in Wjarakarur Kimberlite Field (WKF) assisted in comprehending the response of pipes. In the present study, we have attempted a combined analysis of very low-frequency electromagnetic (VLF-EM), electrical resistivity tomography (ERT), and magnetic methods to analyze the response from pipe 1 and pipe 2. A comparative analysis along all the profiles revealed the extension, depth, and geometry of the pipes. The results of VLF data and ERT data have been compared for two profiles of pipe 1 and pipe 2. Fraser-filtered grid map generated from all profiles of pipe 1 proficiently demarcated the trend of kimberlite pipe extension with high Fraser filter value associated with kimberlite. The ground-based magnetic data around pipe 1, pipe 2, and pipe 6 have been processed to analyze the magnetic behavior and subsurface structure based on the susceptibility contrasts. Analytical signal (AS) map revealed the extension of pipes, which was validated with the Fraser-filtered grid map. Analytical signal anomaly pattern reveals that pipe 1, pipe 2, and pipe 6 are trending in SW-NE, NE-SW, and NE-SW, respectively. Based on this study, the results indicate the conducting nature of pipe 1, whereas pipe 2 is resistive in nature. Further, the Euler deconvolution technique has been applied to calculate the possible depth of pipes from magnetic data. The comparisons of calculated depth ranges obtained from all geophysical techniques correlate well and validate the result (Table 1). The geological borehole data at pipe 1 and pipe 2 reported by the Geological Survey of India are well corroborated with our combined geophysical study.

Jan 17, 2024

By B. Genc

Safety in South African mines is a subject of significant interest, since many mining companies are experiencing production deficits due to safety-related stoppages. In this paper, safety data from the South African platinum mining sector is analysed for the period 2006 to 2010. The data was obtained from company annual reports as well as the Department of Mineral Resources, and analysis in the study is limited to injury and fatality data only. The overall safety performances of companies in the sector are compared, and opportunities for benchmarking and recognising potential sources of best practice amongst platinum miners are identified. Improving safety usually incurs a cost, and mining companies are particularly conscious of the importance of controlling costs. However, cost considerations often deal only with direct costs, and it has been shown that indirect costs are usually far more significant. Therefore, a greater safety spend will usually result in the creation of value for the mine since it will reduce the indirect costs associated with accidents. The results of some recent research in this area are presented. In this light, where available, the financial performances of mining companies in the sector, obtained from published annual results, are included in the benchmarking exercise to determine whether there is any correlation with safety performance.

Jan 1, 2012

By T. G. Hayes

Economic and environmental regulations in the coal industry have required companies to evaluate their current blasting method of loosening in-situ coal. This paper will review ripping vs. blasting thick in-situ coal seams, handling frozen active coal stockpiles and proper stockpile conditioning and reclaiming. How basic operating technique can improve job efficiency, productivity and cost per ton.

Jan 1, 1995

By Guomin Jiang

Potassium ferrate is an excellent multifunctional reagent for wastewater treatment, but its preparation is crucial. The improved hypochlorite oxidation method was used to prepare potassium ferrate in this study. Iron nitrate, the preferred iron source, was added into hypochlorite solution and then the stabilization agent was added during the purification process of product. The influence of available chlorine content, iron molecular proportion, reaction temperature and reaction time on potassium ferrate preparation was investigated. The optimal condition for potassium ferrate preparation is 15% of available chlorine content , 0.6 of iron molecular proportion , 30i of reaction temperature , 45min of reaction time. The yield of potassium ferrate is about 67% with high purity (> 99%). The structure and performances of the product was characterized by XRD, EDX, SEM, TG and IR and the results show that the prepared product is consistent with the properties of potassium ferrate(VI).

Jan 1, 2010

By Max W. Ball

YOU have been kind enough to ask me to speak to you on "The War and Anglo-American Relations." A speaker always takes the liberty of putting his own interpretation on the scope of his subject. I am going to exercise that privilege, and try to look back over a generation of Anglo-American relationships and forward beyond the present war. I should like particularly to consider responsibilities as well as relationships. A more accurate caption for what I am going to say would be "Anglo-American Responsibilities.?? THE WAR WILL BE WON I am assuming that sooner or later we shall win this war. History and economics point to the same conclusion, that Germany has attempted the impossible and that the seeds of defeat are already sown. As to one ecof1:omic factor, I am already on public record as believing that Germany's oil supply is inadequate for the war she has launched. That opinion is unchanged. Aside from such tangible factors, moreover, I am convinced that the spirit of freedom is unquenchable, and that no combination of powers will be able to rout it from the British Commonwealth of Nations and the United States. Stronger even than this conviction is my faith in a God who will not suffer the defeat of man's aspiration to be master of his own soul. I am sure that all of you share that faith, and that we need not argue it. We can start with the assumption that the war will end in victory. The subject we are to consider, then, is the relationship of the English-thinking peoples during the conflict, and their joint responsibilities in the difficult days that will follow it. A CANADIAN-AMERICAN No talk on such a subject is worth listening to unless the audience knows the background and fundamental beliefs of the speaker. No human statement stands alone; behind and beside and within it are the ideals and the bias of the man who makes it. Because I am a stranger to most of you, I am constrained to talk about myself before I talk about more important matters. The review may be profitable, not because of the subject, but because it may illustrate the evolution of an attitude toward England.

Jan 1, 1941

By Laurence Whitty-Léveillé

Proper handling of the radioactive fraction associated with the production of rare earth elements (REEs) in the mining industry is essential for a sustainable environment and human health. Actinides, such as uranium and thorium, have similar chemical properties to REEs, and are often co-dissolved in current hydrometallurgical processes. This causes radioactive contamination of the infrastructure through the extraction cycle. The present study optimizes, through experimental design, a sequential leaching procedure with Na2CO3/NaHCO3 and HCl for the rapid and selective dissolution of REEs and actinides. Optimization focuses on the main operating parameters (time, temperature, and concentration); different types of minerals, REE composites, and ores; on achieving maximal leaching yield; and on minimizing dissolution of the gangue metals (Fe, Si, and Ca). The final sequential procedure was rapid (1 h), effective, and led to the segregation of Th, U, and REEs with limited dissolution of the gangue metals.