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By B. M. Satish

The aim of the present work is to study the effect of annealing on the vibration damping capacity of high-chromium (16%) ferromagnetic steel. The alloys were prepared from raw materials of 99.9% purity melted in a high frequency induction furnace under high vacuum. The samples were heat-treated in vacuum at various temperatures (800 to 1200°C) for 1 hour followed by slow cooling (120°C/h). The inverted torsional pendulum method was used to evaluate the vibration damping capacity. The results indicated that the vibration damping capacity of the alloys is influenced by annealing and there exists a critical annealing temperature after 1000°C. The damping capacity increases quickly below the critical temperature since the magnetic domains move more easily.

Jan 1, 2009

By Aiyuan Ma, Tu Hu, Chenyu Sun, Yonggang Zuo, Hongying Xia, Jinhui Peng, Libo Zhang, Yongguang Luo

"In this study, the adsorption characteristics of tannin acid in aqueous solution were investigated using regenerated activated carbon (AC), with the aim to remove the tannin acid organic matter from the solution after zinc hydrometallurgy and Ge precipitation. Results showed the temperature has little effect on the adsorption ability (q.) of the regenerated activated carbon. The experimental equilibrium data were tested for the Langmuir and Freundlich isotherms. The adsorption equilibrium was better described by the Langmuir isotherm (R2 > 0.99). Pseudo first- and second-order kinetic models were used for describing kinetic data. It was determined that the kinetics of tannin acid removal was well fitted by second-order reaction.IntroductionGermanium recovery is a complex processes [1]. Hydrometallurgical processes are favoured and these are based on the precipitation of germanium as hydroxide or sulphide or alternately with tannic acid [2]. However, in the germanium recovery process, too much tannin is consumed by the germanium-tannins complexation process, and results in a high content of tannic acid remaining in solution, which is harmful to the valuable metal recovery [3]."

Jan 1, 2014

By S C. Dominy

For any gold deposit-based geometallurgical study, the collection and processing of representative samples for gold grade and recovery tests is critical. Sampling protocols should be designed to suit the style of orebody in question. The proportion and size of gold particles has a direct impact on the effectiveness of sampling protocols and metallurgical recovery processes employed. Studies focussing on ore mineralogy and gold particle deportment, size and distribution are required. Key issues are the presence of gold particle clustering (important for sampling optimisation) and proportion of coarse versus fine to refractory gold. X-ray computed tomography (CT) is a radiographic technique that produces high-resolution 3D computerised models of objects based on density distribution. The ‘virtual’ specimens are made up of voxels, the 3D equivalent of pixels each assigned a grey value based on X-ray absorption. This paper presents the results of recent research on the imaging of in situ gold particles in a coarse gold-bearing ore. The technique shows promise as a rapid non-destructive method for preliminary characterisation to facilitate more detailed studies. Early and rapid gold particle determination enables sampling protocol optimisation and metallurgical recovery parameters to be defined prior to detailed feasibility studies

Sep 5, 2011

By Alicia E. Ares

316 L Stainless Steel samples were solidified directionally under conditions which produced the columnar to equiaxed transition. The position of the transition was located in each sample and the distance from the bottom of the ingot was measured. During solidification the distribution of temperatures were measured by means of thermocouples located strategically. From the measured temperatures the following parameters were derived; the local temperature gradient, the cooling rate and the velocities of the liquid and solidus fronts. Comparing the location of the transition and the values of these parameters it was found that the temperature gradient reaches negative values of as low as -13.44 "C/cm, and velocities of the fronts of around 0.1 cm/s. Also, a supercooling of 5.81°C were measured which was associated with the supercooling for the nucleation and growth of the equiaxed grains ahead of the columnar front. In addition the primary and secondary dendritic spacing was measured in both regions. The spacing was compared with the predictions from available models. The results are presented and discussed in the frame of the results obtained for other alloys

Jan 1, 2002

By Rudolf E. Greuer

The existing computer programs for the simulation of ventilation systems under normal ventilation conditions are reviewed and a suitable program for including the influence of mine fires is selected. New program parts are written for the consideration of methane productions in coal mines, heat and gas productions of mine fires, temperature and air composition changes in ventilation systems, and the ventilation forces resulting from the latter. Other program parts are provided for the detection of danger zones and reversed air currents and for the inclusion of recirculated air currents in the network analysis. Existing program and new program parts are combined. The resulting new program can be used for a multitude of assignments. It is designed for the practical ventilation engineer and should be applicable to all types of ventilation emergency plans, in particular mine fire plans. The organization of the program and its mathematical basis are described. A FORTRAN IV listing and several flow diagrams are included. Eight executed examples are discussed, input and output for these examples explained. Storage requirements and execution times are estimated.

Jan 1, 2011

By Malti Goel

"Ferrous and non-ferrous metals industries are source of both direct and indirect greenhouse gas (GHG) emissions. Metal industry accounted for 29.7% of the total GHG emitted from the Indian industry sector in 2007. Aluminum is second largest contributor after steel. Indian Aluminum industry has been growing and is adopting several effective measures for better efficiencies through process change and waste utilization. Improvement in the energy efficiency can form the basis of monitoring reduction in emissions. Under the National Action Plan on Climate Change 2008, National Mission for Enhanced Energy Efficiency (NMEEE) aims to upscale the efforts to unlock the market for energy efficiency improvement on a public private partnership (PPP) basis. For a transition to low carbon economy industry is undertaking voluntary measures through scientific and technological innovations both in upstream and downstream sectors. In this paper an attempt is made to overview recent developments in Indian Aluminum industry as well as summarize scientific & technological challenges and prospects.IntroductionAluminum plays a vital role in industrial development. It is a substitute for different type of materials ranging from wood to copper and steel. The aluminum industry has high energy consumption and high contribution to greenhouse gases from carbon dioxide and perfluorocarbons (PFCs) emissions. It is estimated that CO2 equivalent burden of aluminum industry is about 1% of total anthropogenic emissions. The anticipated world growth rate is 3.5% for aluminum demand. Through measures to reduce both direct and indirect CO2 emissions, electricity consumption was reduced from 25 kWh / kg of Aluminum in 1998 to 15 kWh / kg of Aluminum produced in 2008. It is targeted to further reduce it to 10.8 kWh. Aluminum industry is also responsible to about 60% of all PFC emissions. The PFC emissions are harmful to environment, accumulate in surrounding vegetation and contaminate. Efforts to reduce PFC emissions from aluminum industry started early and reduced to 0.5-1 kg / tonne in 1990 [1] from 12-15 kg / tonne in 1940. Since 1990s to 2000 it further reduced to 0.2 -0.4 kg / tonne as seen in Fig. 1. The Global Aluminum Sustainable Development Initiative (GADSI), targets perfluorocarbon (PFC) specific emissions reduction of 80% for 2010 relative to 1990."

Jan 1, 2011

By J. S., Douglas

IN 1880, the late James Douglas, LL.D., was superintendent of the Chemical Copper Co., operating the Hunt & Douglas process for the treatment of the siliceous copper ores of the Jones mine at Phoenixville, Pa. In conjunction with this a refining furnace was operated. After correspondence with Ben Williams, of Bisbee Ariz., who was commencing the mining and smelting of the Copper Queen ore. Dr. Douglas decided-to make his first journey to Arizona. While making plans for the trip lie visited a friend in Philadelphia, a .Mr. Logan, a prominent lawyer. He, through Professor Treadwell, brother of the discoverer of the great Treadwell gold mine of Douglas Island, Alaska, had an option with his min¬ing partner, Mr. Lenig, on the Eureka and Wade Hampton claims near the headwaters of the Verde River in Yavapai County, Arizona. These two claims, later the source of practically all of the wealth of the Jerome district, were then owned by C. P. Head and Co. Prescott merchants. Hugo Richards, banker, and formerly sutler at Camp Apache; Rod and John McKinnon prospectors and Nova Scotians; and perhaps one or two 'other owners of minor interests. Mr. Logan, hearing of Dr. Douglas intended trip to Bisbee, asked him to go first to see the two mining prospects, and this, Douglas, in need of the $500 fee, agreed to do as the time on the option on the claims was running short.

Jan 1, 1935

By Ronald B. Stotelmeyer

This report summarizes studies of 55 Idaho national forest roadless areas completed by the U.S. Bureau of Mines (USBM) in the period 1966-1992. These roadless areas have been recommended for addition to the National Wilderness Preservation System, proposed as special management areas, or otherwise recommended for study by the U.S. Forest Service or the Idaho congressional delegation. The Bureau of Mines' studies indicate which parts of the roadless areas contain mineral resources. They also show where mining and prospecting are likely to occur in the future, where mineral production has occurred in the past, and where abandoned mine workings (possible hazards) would be encountered. The number of mine and prospect workings found are a measure not only of surface disturbance, but of areas not wilderness in character.

Jan 1, 1994

By Steve Thoman

After the 1989 Loma Prieta Earthquake, the California Department of Transportation (Caltrans) initiated an overview of the Caltrans Bridge Design Specifications (BDS) and bridge seismic design practice in California. This overview is continuing under the direction of the Applied Technologies Council (ATC-32), to review and revise as necessary existing standards, performance criteria, specifications, and practices for design and construction of new bridge structures within California. The ATC-32 project began in August 1991 and is expected to be completed in 1995. Since 1990, Caltrans project-specific seismic criteria have been developed and implemented on the I-280 and I-480 projects in San Francisco. Caltrans and an independent seismic safety review panel continue to develop and implement these criteria on other projects. In 1991 and 1992, project-specific seismic criteria were used on the I-880 reconstruction project in Oakland. The seismic safety review panel considered the I-880 seismic design criteria a state-of-the-art methodology to ensure seismic safety against collapse of bridge structures subjected to a maximum credible seismic event. This paper highlights the 1992 "I-880 Reconstruction Project Seismic Design Criteria Review" report prepared by the Seismic Safety Review Panel and Caltrans Division of Structures and will compare pre-1989 BDS and AASHTO methodologies to the I-880 criteria.

Jan 1, 1996

By M. M. Kim

As-electrogalvanized coatings of pure Zn, Zn-11% Fe, and Zn-18% Fe coatings were characterized in terms of initial crystal structure and surface morphology. Samples were then subjected to heat treatments simulating the paint bake cycle of automobile manufacturers. Surface morphology changes were correlated with the process variables, and crystallo.graphic changes were interpreted by mapping heat treatment routes on the Fe-Zn phase diagram. The morphology of pure zinc electrogalvanized coatings with heat treatment from platelets to smeared platelets. The zn-11% Fe coating changes with heat treatment from tetrahedral nodules to a mixture of round and tetrahedral nodules, with the Zn-:18% Fe coating always having round nodules. Regarding crystal structure, a critical transformation time can be defined at any selected temperature, below which the crystal structure does not change. This temperature is related to iron content.

Jan 1, 1990

In recent years, wide consideration has had to be given to methods of improving the condition of the mine environment in many coal mines, and significant developments and changes have evolved. Thus even after substantial increases inòair flow rates at the working place (they have increased over three fold in the last generation), environmental conditions have arisen for which it has been necessary to introduce or consider: i) additional ameliorative measures, such as good housekeeping; ii) layout changes: such as Y or Z layouts; iii) homotropal ventilation; and iv) air conditioning. In certain countries, consideration has been given also to: v) additional payments reduced working times; vi) heat acclimatisation programmes; and vii) the use of cold or cooling suits At many hot and humid mines, the principal benefits from adopting (i), (ii) and (iii) have already been realised. At such mines,

Jan 1, 1983

By W. Dietzel

Fracture mechanics based techniques are used to gain insight into the phenomenon of stress corrosion cracking (SCC) and to develop guidance for avoiding or controlling SCC. From constant extension rate experiments under rising load or rising displacement conditions the susceptibility of high strength steels, aluminum, magnesium and titanium alloys to SCC and hydrogen embrittlement can be assessed. Such tests on pre-cracked specimens are also well suited for studying the mechanisms leading to SCC by employing appropriate models for the degradation of metallic materials which take into account the uptake of atomic hydrogen from the corrosive environment. Measurements of crack growth resistance curves using the crack tip opening displacement as fracture parameter can be compared with simulated R-curves obtained from modeling of the mechanism of hydrogen embrittlement. The materials investigated are a high strength steel and a magnesium alloy both exposed to environmental conditions which fostered the uptake of hydrogen.

Jan 1, 2010

By Xintan Chang

MFIRE is a computer simulation program that performs normal ventilation network planning calculations and dynamic transient-state simulation of ventilation networks under a variety of conditions. The program is useful for the analysis of ventilation networks under the influence of natural ventilation, fans, fires, or any combination of these. MFIRE simulates a mine's ventilation system and its response to altered ventilation parameters such as the development of new mine workings or changes in ventilation control structures, external influences (varying outside temperatures), and internal influences (fires). Extensive output enables detailed, quantitative analysis of the effects that the alteration will cause to the ventilation system. The program was developed at Michigan Technological University (MTU), Houghton, MI, with support from the Bureau of Mines. A personal computer (PC) version of the program was completed under contract for the Bureau by MTU. The purpose of this report is to document the installation and use of the PC version of the program MFIRE.

Jan 1, 1990

By Nora M. Hutt, Kevin A. Morin

The Sobek humidity cell has been in use with minor modification for more than 30 years to determine bulk primary-mineral reaction rates. As a result, it has become a key tool for predicting the bulk rate of sulphide oxidation, the Carbonate Mole Ratio (CMR) of neutralization-potential (NP) consumption to sulphide oxidation, and the rates of metal leaching. Most humidity cells are operated for less than a year, with the resulting rates extrapolated into the future for years or decades. The validity of these extrapolations was tested by examining longer trends from cells that have operated for three to seven years, as found in the International Kinetic Database (IKD). Additionally, large batches of cells for two minesites in the IKD (45 and 46 cells each) were examined to determine if regular, predictable trends were obtained across ranges of geochemistry at a minesite. The long-term cells show that the rates of sulphide oxidation and acid generation, based on sulphate production, have a 50% chance of stabilizing within one year, with the remainder fluctuating significantly throughout their test periods. Despite the fluctuations, the CMR, which is critical for defining site-specific or rock-unit-specific ABA criteria, remains relatively steady in many cases between 1.0 and 2.0 as expected from principles of aqueous geochemistry. However, if the sulphate-production rate falls below 10-30 mg/kg/wk, the CMR value can increase significantly. At and below these low rates, physical factors like flow rates of surface waters and groundwaters will determine the rate of NP consumption, rather than geochemical factors. Also, if weekly rinse pH falls to acidic values, the CMR will decrease below 1 .O, reflecting the exhaustion of fast- neutralizing minerals. The two batches of multiple cells also confirm these trends across arange of geochemistry. The long-term cells show that copper leaching often stabilizes within a narrow range as long as rinse pH remains relatively constant. Also, there is no strong dependence of leaching on the sulphate rate. However, the rate of copper production often increases sharply if rinse pH falls to acidic values. This suggests the measured copper-production rate in some cases is not a true primary rate, but a lower secondary rate after secondary- mineral precipitation within Sobek cells. As with the long-term cells, the batches of multiple cells show that copper production often increases gradually with decreasing rinse pH, with no clear dependence on sulphate production. However, high rates can also occur at near-neutral pH, so secondary-mineral precipitation of copper is not necessarily common.

Jan 1, 2000

By J. W. Horne, W. L. Finley, A. D. Bauer, D. W. Gould

"The Bureau of Mines and the State of Colorado are cooperating in an investigation of the oil shales of Colorado. in this report the yields and the results of analyses of the oil and, gas produced from a number of oil-shale samples from the principal deposits of Colorado and other oil-shale States, are compared with samples from Scotland and Australia, where the oil-shale industry has had its greatest commercial development, and also with a sample from Brazil *here extensive oil-shale deposits are found shale samples were not selected as being representative of the different deposits, but they illustrate the wide variation in the nature of the organic matter of different oil shales.A further study is being made of the chemical composition of the shale, distribution of nitrogen and sulphur. in the products, temperatures at which organic matter decomposes, and the results will be presented in subsequent Papers, With complete data available on the chemical composition of the shales, it may be possible to explain some of the differences in the nature of the products from the various shales,Most of the work described herein was done under the supervision of M. J. Gavin. L. C. Karrick, formerly of .the Boulder laboratory, assisted in the work and gave many valuable suggestions."

May 1, 1924

By Nn Li

Energy consumption in commercial buildings has been increasing rapidly in the past decade. The knowledge of future energy consumption can bring significant value to commercial building energy management. For example, prediction of energy consumption decomposition helps analyze the energy consumption patterns and efficiencies as well as waste, and identify the prime targets for energy conservation. Moreover, prediction of temporal energy consumption enables building managers to plan out the energy usage over time, shift energy usage to off-peak periods, and make more effective energy purchase plans. This paper proposes a novel model for predicting heating, ventilation and air conditioning (HVAC) energy consumption in commercial buildings. The model simulates energy behaviors of HVAC systems in commercial buildings, and interacts with a multiagent systems (MAS) based framework for energy consumption prediction. Prediction is done on a daily, weekly and monthly basis. Ground truth energy consumption data is collected from a test bed office building over 267 consecutive days, and is compared to predicted energy consumption for the same period. Results show that the prediction can match 92.6 to 98.2% of total HVAC energy consumption with coefficient of variation of the root mean square error (CV-RMSE) values of 7.8 to 22.2%. Ventilation energy consumption can be predicted at high accuracies (over 99%) and low variations (CV-RMSE values of 3.1 to 16.3%), while cooling energy consumption accounts for majority of inaccuracies and variations in total energy consumption prediction.

Aug 1, 2013

By R. L. Crosby

Microscopical and X-ray diffraction techniques were used to identify two intermediate phases in that part of the solid region of the magnesium-cerium system between and Mg3Ce. Previous literature had reported only one intermediate phase for this region, 1)12t chemical analysis determined the approximate composition of the two compounds to be Mg23Ce2 and Mg17Ce2. The range in composition of the two intermediate phases was found to be limited to less than 0.3 atomic percent cerium. The study did not determine the crystal structure of Mg17Ce2, but that of Mg23Ce2 is tetragonal with a = 10.33 A and c = 19.51 A.

Jan 1, 1966

By R. R. Kallu

The current 120 psi seal design and evaluation practices are mostly based on simple analytical solutions. Considering the simplistic assumptions and limitations involved in simple analytical solutions and practical difficulties involved in conducting conventional full-scale explosion tests for evaluating 120 psi seal designs, there is a need for developing new scientific methods and engineering practices for design, analysis and evaluation of mine seals.

Jan 1, 2010

By Roy A. White

The development of a fire and rot-resistant coating treatment for mine timbers, along with the associated processing technology, is described. Included are a literature search, laboratory studies of polyimide-fungicide coatings, and leaching and fungus growth studies on coated wood blocks. Finally, an economic analysis is performed tor various levels of production.

Jan 1, 1977

By AIME AIME

THE American Institute of Mining and Metallurgical Engineers will hold its annual meeting in New York City, Feb. 9-12. The technical sessions, excepting the Sunday afternoon and evening sessions of the Mineral Industry Education Division (see the M.I.E.D. program) will be held in the Engineering Societies Building. The "All-Institute" luncheon on Monday will be at the Commodore Hotel; the Annual Banquet and President's Reception, the Smoker, and the Informal Dance will be at the Waldorf Astoria Hotel. The dinners of the Petroleum Division and the Institute of Metals Division will be at the Roosevelt Hotel.

Jan 1, 1942