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461.
In optoelectronics assembly, the first few stages of the assembly line are dedicated to build the product and the later stages are dedicated for calibration and testing. The assembly line is arranged in a flow shop environment with multiple processors at each stage. When a product (or job) fails at a stage, it is routed back to one of the previous stages or to the same stage (depending upon the nature of the failure). Consequently, the product could circulate between the current stage and the previous stage(s) before it is transferred to the next stage. Estimating the performance measures of such complex manufacturing systems, while considering multiple product classes, random job failures, and resource sharing, is not trivial. This paper presents the approximations used to estimate the performance measures of such complex manufacturing systems with general arrival and service distributions. The analytical approximations have been validated using discrete event simulation and the source of error between them is identified. These approximations can be used by operations managers to estimate the performance measures such as WIP and flow time. 相似文献
462.
The corona discharge process was studied using Box–Behnken design of experiments in conjunction with response surface methodology of analysis. The single as well as interaction effects of process factors namely applied voltage, time of charging, and distance between electrodes on the surface potential of meltblown nonwoven electret media were examined. The response surface model predicting the surface potential of the electrets displayed a very good correspondence with the experimental results. The optimized corona discharge process run by keeping the predicted levels of process factors yielded surface potential of the electret media very close to that predicted from the model. 相似文献
463.
Noise pollution is one of the major public health problems in urban
areas throughout the world. Noise is unwanted sound which produces undesirable
problems in day to day life of human being (e.g., physiological and psychological
problems). Rapid increase of the industrialization, urbanization, infrastructure,
volume of motor vehicles, and increase in the road networks brought noise pollution
to the highest level of disaster in a current situation. In urban areas, road traffic
noise plays commanding role among all noise sources and affects the exposed
inhabitants. The present work is done to evaluate and assess the traffic noise and
its effects in Burla town.
Burla, Vidyanagari of Odisha, is an emerging town in India, as it hosts national
level of teaching and research institutions like IIM Sambalpur, a medical college-
cum-hospital (VIMSAR), a technical university (VSSUT) and Sambalpur
University. In last two decade, the road traffic volume has been increased and
is facing severe noise pollution to its inhabitants. Noise pollution assessment
was made at different locations of the town. This study unveiled the dismal state
of noise pollution in the town. Noise contour maps were drawn to visualize the
noise level at the traffic and its surroundings. The numbers of hearing impaired
patients in different hospitals of the locality are increasing. That shows grim picture
of the situation. Regression equations were established taking noise levels
with percentage of highly annoyed people during study indicates strong
correlation. 相似文献
464.
Dr. Supriya Ghosh Dr. Debkumar Rana Dr. Bapi Pradhan Dr. Patrice Donfack Prof. Dr. Johan Hofkens Prof. Dr. Dr. Arnulf Materny 《Chemphyschem》2023,24(21):e202300303
In recent years, there has been an impressively fast technological progress in the development of highly efficient lead halide perovskite solar cells. Nonetheless, the stability of perovskite films and associated solar cells remains a source of uncertainty and necessitates sophisticated characterization techniques. Here, we report low- to mid-frequency resonant Raman spectra of formamidinium-based lead mixed-halide perovskites. The assignment of the different Raman lines in the measured spectra is assisted by DFT simulations of the Raman spectra of suitable periodic model systems. An important result of this work is that both experiment and theory point to an increase of the stability of the perovskite structure with increasing chloride doping concentration. In the Raman spectra, this is reflected by the appearance of new lines due to the formation of hydrogen bonds. Thus, higher chloride doping results in less torsional motion and lower asymmetric bending contributing to higher stability. This study yields a solid basis for the interpretation of the Raman spectra of formamidinium-based mixed-halide perovskites, furthering the understanding of the properties of these materials, which is essential for their full exploitation in solar cells. 相似文献