748 research outputs found

    Risk analaysis of ethanol blending fuel in refinery industry using event tree analysis and Topsis method

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    Chemicals have always posed risks including fire, explosion, and the release of harmful substances in process industries like the Petroleum Industry. The occurrence of such catastrophes has a significant impact on the resources for finances and daily living. In this research paper, the major safety-related causes and effects are identified through event tree analysis based on accidents and incidents while using ethanol as fuel. For this purpose, the accident and incident data collected so far while using ethanol in the fuel industry, detailed information about ethanol, and even tree analysis. The event tree analysis (ETA) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) analysis method is utilized to Identifying an initiating event of interest of accident. The event tree\u27s structure also aids the analyst in identifying the locations where additional protocols or safety measures are required to mitigate accidents or lower their frequency

    Vibration analysis and control in linear switched reluctance motor

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    Vibration is one of the major drawbacks of Linear Switched Reluctance Motor (LSRM). Two design techniques to reduce vibration in the LSRM are proposed. A detailed mathematical approach for calculating natural frequency has been outlined. Different techniques to predict the vibration frequencies are analyzed using ANSYS software. The analyzed structures are compared by using experimental and simulation results

    Multi-objective optimization in single-row layout design using a genetic algorithm

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    This paper presents the development of a genetic algorithm for determining a common linear machine sequence for multi-products with different operation sequences and facilities with a limited number of duplicate machine types available for a job. This work aims to minimize the total flow distance travelled by products, reduce the number of machines arranged in the final linear sequence, and decrease the total investment cost of the machines used in the final sequence. We assume that product flow runs only in the forward direction, either via in-sequence or bypass movement. We demonstrate the effectiveness of the proposed algorithm by solving a typical layout design problem taken from literature, and several randomly generated problems. Results indicate that the proposed algorithm serves as a practical decision support tool for resolving layout problems in manufacturing facilities

    Convergent evolution of reduced energy demands in extremophile fish

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    Citation: Passow, C. N., Arias-Rodriguez, L., & Tobler, M. (2017). Convergent evolution of reduced energy demands in extremophile fish. PLOS ONE, 12(10), e0186935. https://doi.org/10.1371/journal.pone.0186935Convergent evolution in organismal function can arise from nonconvergent changes in traits that contribute to that function. Theory predicts that low resource availability and high maintenance costs in extreme environments select for reductions in organismal energy demands, which could be attained through modifications of body size or metabolic rate. We tested for convergence in energy demands and underlying traits by investigating livebearing fish (genus Poecilia) that have repeatedly colonized toxic, hydrogen sulphide-rich springs. We quantified variation in body size and routine metabolism across replicated sulphidic and non-sulphidic populations in nature, modelled total organismal energy demands, and conducted a common-garden experiment to test whether population differences had a genetic basis. Sulphidic populations generally exhibited smaller body sizes and lower routine metabolic rates compared to non-sulphidic populations, which together caused significant reductions in total organismal energy demands in extremophile populations. Although both mechanisms contributed to variation in organismal energy demands, variance partitioning indicated reductions of body size overall had a greater effect than reductions of routine metabolism. Finally, population differences in routine metabolism documented in natural populations were maintained in common-garden reared individuals, indicating evolved differences. In combination with other studies, these results suggest that reductions in energy demands may represent a common theme in adaptation to physiochemical stressors. Selection for reduced energy demand may particularly affect body size, which has implications for life history evolution in extreme environments

    A simple heuristic for linear sequencing of machines in layout design

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    This paper presents a simple heuristic to determine a common linear machine sequence for multiple products with different operation sequences and a limited number of duplicate machine types available for the job. The heuristic is based on minimisation of the total flow distance travelled by a product on the linear machine sequence. It is assumed that the flows of products are allowed only in the forward direction, either in-sequence or by-pass. It is also assumed that backtrack movements are not allowed. The effectiveness of the proposed heuristic is demonstrated through the solutions of two typical layout design problems taken from the literature. Subsequently, a number of additional problems are solved and their results are compared with the results applying existing methods. The results indicate that the proposed method can be an effective tool in solving layout design problems

    Vibration analysis and control in linear switched reluctance motor

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    Vibration is one of the major drawbacks of Linear Switched Reluctance Motor (LSRM). Two design techniques to reduce vibration in the LSRM are proposed. A detailed mathematical approach for calculating natural frequency has been outlined. Different techniques to predict the vibration frequencies are analyzed using ANSYS software. The analyzed structures are compared by using experimental and simulation results

    Quantifying Metal Contamination and Potential Uptake by Phragmites australis Adans. (Poaceae) Along a Subtropical River System

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    Metal pollution is pervasive across terrestrial and aquatic ecosystems owing to anthropogenic activities. Sediments can accrue high concentrations of metals and act as secondary sources, and thus may be valuable indicators of metal contamination across spatiotemporal scales. In aquatic systems, the extent of metal pollution may be further mediated by transference among sediments and living organisms, with plant metal contaminants potentially predictive of underlying sediment concentrations. The present study thus quantifies the extent of metal pollutants (Na, K, Ca, Mg, Cu, Zn, Mn, B, Fe) across multiple study sites and seasons (cool-dry, hot-wet, hot-dry) in a subtropical river system. Furthermore, uptake by a key macrophyte species, Phragmites australis, was examined and correlated with sediment pollution levels among different plant parts. Overall, sediment pollution load indices differed seasonally, being significantly highest during the cool-dry season irrespective of sampling location, suggesting that periods with reduced water flows can exacerbate metal pollution levels in riverine sediments. Also, metal concentrations were highest in upstream wetland sites, indicating a capacity for metal sink effects in these areas. Overall, macrophytes contained high concentrations of select metals, however composition and concentrations differed across plant parts, with roots containing particularly high concentrations of Fe and B. Correlations between sediment and macrophyte concentrations were mostly non-significant, whilst stem Mn and Fe concentrations correlated significantly negatively and positively to sediment concentrations, respectively. The present study identifies key spatiotemporal differences in multiple metal contaminants in an understudied subtropical aquatic system that align with hydrological regime differences. Whilst macrophytes were not found to be major accumulators, or predictors, of metal contaminants in this study, they may collectively play a central role in concentration regulation in aquatic systems
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