143 research outputs found

    Requirements for the conceptual design of advanced underground coal extraction systems

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    Conceptual design requirements are presented for underground coal mining systems having substantially improved performance in the areas of production cost and miner safety. Mandatory performance levels are also set for miner health, environmental impact, and coal recovery. In addition to mandatory design goals and constraints, a number of desirable system characteristics are identified which must be assessed in terms of their impact on production cost and their compatibility with other system elements. Although developed for the flat lying, moderately thick seams of Central Appalachia, these requirements are designed to be easily adaptable to other coals

    Evaluation of ADAM/1 model for advanced coal extraction concepts

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    Several existing computer programs for estimating life cycle cost of mining systems were evaluated. A commercially available program, ADAM/1 was found to be satisfactory in relation to the needs of the advanced coal extraction project. Two test cases were run to confirm the ability of the program to handle nonconventional mining equipment and procedures. The results were satisfactory. The model, therefore, is recommended to the project team for evaluation of their conceptual designs

    A Simple, Rapid and Efficient One-pot Protocol for the Synthesis of 2-substituted Benzothiazole Derivatives and their Antimicrobial Screening

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    A rapid and efficient condensation reaction of 2-aminothiophenol with various fatty acids in solvent-free conditions with or without microwave irradiation was carried out to afford the corresponding 2-substituted benzothiazole derivatives in good to excellent yields. The structures of the new products were established by elemental analyses, IR, 1H NMR, 13C NMR and mass spectral data. All the title compounds were screened for their antibacterial and antifungal activity. Most of the compounds exhibited good antimicrobial activity.Keywords: Fatty acids, 2-substituted benzothiazole, 2-aminothiophenol, antimicrobial activity, microwave irradiatio

    Ventilation-on-Demand: Quantity or Quality — A Pilot Trial at Barrick Gold\u27s Bousquet Mine

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    Common to many established mines in Canada, is the problem that their ventilation systems are continually being stretched to meet new needs that were not anticipated in the original design. This can be the result of a variety of different factors, such as the discovery of new reserves at depth, accelerated production, new worker exposure regulations or a change of mining method. At Bousquet, the ventilation of a new multilevel mining block over 1 km away from the existing bottom of the mine presents a challenge. The airflow available for this region is limited to 57 m3/s by the size of a ventilation drift and raise, and by the total volume the mine can supply. This volume is sufficient only if it can be directed to the desired locations, namely where the diesel equipment is operating and with minimal losses (\u3c10%). Due to the mobile nature of the mining equipment and changing production areas, such tight management of air can only be achieved with Ventilation on Demand . This paper describes a pilot trial, within the existing mine, of an automated demand based ventilation management system. Vehicle tracking and identification determine ventilation demand, location and duration. Specific air volumes are achieved with remote controlled regulators, and auxiliary fan systems and verified with airflow monitors. Air quality is monitored with gas sensors. Based upon this trial the mine will be able to determine the viability of an air quality driven system over an engine based air quantity dictated system. This would then, with the approval of the local regulators, allow the mine to operate its ventilation more efficiently and gain the maximum benefit of cleanengine technology and exhaust treatment devices

    Fractional differentiability of nowhere differentiable functions and dimensions

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    Weierstrass's everywhere continuous but nowhere differentiable function is shown to be locally continuously fractionally differentiable everywhere for all orders below the `critical order' 2-s and not so for orders between 2-s and 1, where s, 1<s<2 is the box dimension of the graph of the function. This observation is consolidated in the general result showing a direct connection between local fractional differentiability and the box dimension/ local Holder exponent. Levy index for one dimensional Levy flights is shown to be the critical order of its characteristic function. Local fractional derivatives of multifractal signals (non-random functions) are shown to provide the local Holder exponent. It is argued that Local fractional derivatives provide a powerful tool to analyze pointwise behavior of irregular signals.Comment: minor changes, 19 pages, Late

    Comparative Analysis of Flywheel under Conventional and Composite Materials

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    This paper presents “COMPARATIVE ANALYSIS OF FLYWHEEL UNDER CONVENTIONAL AND COMPOSITE MATERIALS”. Our objective is to demonstrate the application of composites over conventional materials like steel. Conventional engineering materials like steel has high density due to which the inertia of the components are more. Especially during rotations the forces are more due to higher mass. hence, this will give rise to more vibrations due to high imbalance force. So this can be reduced by using composite materials over conventional materials whose density is less and has higher strength to weight ratio

    Holder exponents of irregular signals and local fractional derivatives

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    It has been recognized recently that fractional calculus is useful for handling scaling structures and processes. We begin this survey by pointing out the relevance of the subject to physical situations. Then the essential definitions and formulae from fractional calculus are summarized and their immediate use in the study of scaling in physical systems is given. This is followed by a brief summary of classical results. The main theme of the review rests on the notion of local fractional derivatives. There is a direct connection between local fractional differentiability properties and the dimensions/ local Holder exponents of nowhere differentiable functions. It is argued that local fractional derivatives provide a powerful tool to analyse the pointwise behaviour of irregular signals and functions.Comment: 20 pages, Late
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