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41.
42.
This paper deals with the cost-benefit analysis of a one-server two-identical-unit cold standby system with repair and preventive maintenance (PM). The PM is of the type where the operating unit is taken up for PM whenever the other unit is available for operation. Initially, one unit is placed in operation and the other unit is kept as a cold standby. When the operating unit fails while the other unit is under service (repair or PM), the system breaks down. The busy period of the server in a time interval (O, t] is divided into time spent for repair and time spent for PM. By identifying regenerative epochs, suitable expressions for the expected values of these times are obtained. The pointwise availability is also derived. With the assumptions that a revenue is earned linearly with up-time, and repair and PM costs are incurred linearly with repair and PM times, respectively, the net expected revenue for a period (O, t] is derived. A particular case where the time to failure of the operating unit is 2-Erlang and the times for repair and PM are exponential has been analysed. 相似文献
43.
Kamenan Koffi A. Jagadeesh Anooja Kre N’guessan Raymond Assanvo Edja Florentin Soman Suraj Unni K. N. Narayanan 《Journal of Materials Science: Materials in Electronics》2021,32(11):14217-14217
Journal of Materials Science: Materials in Electronics - A correction to this paper has been published: https://doi.org/10.1007/s10854-021-06180-2 相似文献
44.
R. Gopalan K. Muraleedharan T. S. R. K. Sastry A. K. Singh V. Joshi D. V. Sridhara Rao V. Chandrasekaran 《Journal of Materials Science》2001,36(17):4117-4123
Structural transformations and microstructural characterisation of Sm2Co17 alloys containing Fe, Cu and Zr at different stages of thermal processing have been investigated by X-ray diffraction, optical, scanning electron and transmission electron microscopes. Solution treated samples consist of a mixture of hexagonal TbCu7 (1:7 H) and rhombohedral Th2Zn17 (2:17 R) structure types of 2:17 phase. After isothermal aging, TbCu7 + Th2Zn17 structures transform into Th2Zn17 type structure with precipitation of Cu-rich hexagonal SmCo5 (1:5 H) and Zr-rich platelet phases. In addition to the main phases, a soft magnetic phase of composition Zr6(FeCo)23 is formed in alloys containing higher Zr composition. Isothermal aging studies reveal that magnetic properties show a peak value when aged at 1108–1123 K for 10 h. TEM studies show cellular precipitate structure with cell interiors having 2:17 R structure, while the fully coherent cell boundaries have the 1:5 H structure. Zr-rich platelets which run across many cells and cell boundaries were found to have 1:7 H structure. 相似文献
45.
Electrochemical copolymerization of diphenylamine (DPA) with o‐chloroaniline (OCA) was performed in aqueous 4M sulfuric acid using the pulse potentiostatic method (PPSM). By employing the tunable parameters in PPSM, polymeric films were deposited under different conditions. Cyclic voltammetry was used for evaluating the characteristics of the deposited polymeric films. A suitable growth equation for the deposition of polymer, relating the charge associated for the film deposition and the pulse parameters in PPSM, was deduced. Various surface parameters are evaluated. The formation of copolymer during PPSM deposition was revealed through critical analysis of the results. The characteristic differences between the individual homopolymers, poly(diphenylamine) and poly(o‐chloroaniline) and the copolymer, poly(diphenylamine‐co‐o‐chloroaniline), were brought out. The copolymer was also synthesized through a chemical method and characterized through infrared and ultraviolet‐visible spectroscopic analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 389–397, 2003 相似文献
46.
Unexpected optical contrast at antiparallel domain walls is observed in non-stoichiometric lithium niobate. This is imaged using near-field scanning optical microscopy. A detailed modeling of the imaging process is performed, and a comparison of the experimental and simulation images is used to extract the index profile across a single antiparallel domain wall. 相似文献
47.
This paper deals with the cost-benefit analysis of 1-server 2-unit system with imperfect switch where the items (units/switch) are not ‘as good as new’ after the repair. The successive repair times of each item are arbitrarily distributed while the successive failure rates are constants. If repair of a unit is not possible it is discarded incurring some salvage value. After a fixed number of failures the unit is scrapped without any salvage value. The switch is always repairable and is scrapped only when both the units are scrapped. The expected revenue, expected busy period due to different types of repairs of units/switch, expected salvage value and expected number of repair completions of the switch, all in [0, t], are obtained to carry out the cost-benefit analysis. 相似文献
48.
Membrane-based processes are becoming increasingly important in the field of industrial gas separation. Such processes are attractive from the standpoint of high separation selectivity and high conversion ratios in cases involving gas phase and gas–solid reactions. In particular, the application of dense ceramic mixed ionic and electronic conducting membranes to separate gases such as oxygen through ambipolar transport of oxygen ions and electrons and hydrogen through ambipolar transport of protons and electrons from gas mixtures at elevated temperatures (>500°C) is gaining increasing importance. As a specific example, the requirement of high-purity tonnage hydrogen with less than 10 ppm carbon monoxide impurity levels would be absolutely essential for low-temperature proton exchange membrane fuel cells to gain wide market acceptance. We analyze herein a novel membrane-based hydrogen separation process which has heretofore not been widely reported in the literature. 相似文献
49.
Gang Zhong Jagadeesh K. Venkatesan Henning Madry Magali Cucchiarini 《International journal of molecular sciences》2023,24(1)
Mitochondria are the key biological generators of eukaryotic cells, controlling the energy supply while providing many important biosynthetic intermediates. Mitochondria act as a dynamic, functionally and structurally interconnected network hub closely integrated with other cellular compartments via biomembrane systems, transmitting biological information by shuttling between cells and tissues. Defects and dysregulation of mitochondrial functions are critically involved in pathological mechanisms contributing to aging, cancer, inflammation, neurodegenerative diseases, and other severe human diseases. Mediating and rejuvenating the mitochondria may therefore be of significant benefit to prevent, reverse, and even treat such pathological conditions in patients. The goal of this review is to present the most advanced strategies using mitochondria to manage such disorders and to further explore innovative approaches in the field of human mitochondria-based therapies. 相似文献
50.
Kamenan Koffi A. Jagadeesh Anooja Kre N’guessan Raymond Assanvo Edja Florentin Soman Suraj Unni K. N. Narayanan 《Journal of Materials Science: Materials in Electronics》2021,32(11):14207-14216
Journal of Materials Science: Materials in Electronics - We successfully fabricated dye sensitized solar cells (DSSCs) employing a quasi-solid state electrolyte based on pristine insulator natural... 相似文献