378 research outputs found

    Fire Safety Analysis of a Railway Compartment using Computational Fluid Dynamics

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    Trains are considered to be the safest on-land transportation means for both passengers and cargo. Train accidents have been mainly disastrous, especially in case of fire, where the consequences are extensive loss of life and goods. The fire would generate smoke and heat which would spread quickly inside the railway compartments. Both heat and smoke are the primary reasons of casualties in a train. This study has been carried out to perform numerical analysis of fire characteristics in a railway compartment using commercial Computational Fluid Dynamics code ANSYS. Non-premixed combustion model has been used to simulate a fire scenario within a railway compartment, while Shear Stress Transport k-ω turbulence model has been used to accurately predict the hot air turbulence parameters within the compartment. The walls of the compartment have been modelled as no-slip stationary adiabatic walls, as is observed in real life conditions. Carbon dioxide concentration (CO2), temperature distribution and air flow velocity within the railway compartment has been monitored. It has been observed that the smoke above the fire source flows to both sides of the compartment. The highest temperature zone is located downstream the fire source, and gradually decreases with the increase in the distance from the fire source. It can be seen that CFD can be used as an effective tool in order to analyse the evolution of fire in railway compartments with reasonable accuracy. The paper also briefly discusses the topical reliability issues

    Design of an optimal multi-layer neural network for eigenfaces based face recognition

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    Face recognition is one of the most popular problems in the field of image analysis. In this paper, we discuss the design of an optimal multi-layer neural network for the task of face recognition. There are many issues while designing the neural network like number of nodes in input layer, output layer and hidden layer(s), setting the values of learning rate and momentum, updating of weights. Lastly, the criteria for evaluating the performance of the neural network and stopping the learning are to be decided. We discuss all these design issues in the light of the eigenfaces based face recognition. We report the effects of variations of these parameters on number of training cycles required to get optimal results. We also list the optimized values for these parameters. In our experiments, we use two face databases namely ORL and UMIST. These databases are used to construct the eigenfaces. The original faces are reconstructed using the top eigenfaces. The factors used in the reconstruction of the faces are used as the inputs to the neural network

    Lossless gray image compression using logic minimization

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    A novel approach for the lossless compression of gray images is presented. A prediction process is performed followed by the mapping of prediction residuals. The prediction residuals are then split into bit–planes. Two-dimensional (2D) differencing operation is applied to bit-planes prior to segmentation and classification. Performing an Exclusive-OR logic operation between neighboring pixels in the bit planes creates the difference image. The difference image can be coded more efficiently than the original image whenever the average run length of black pixels in the original image is greater than two. The 2d difference bit-plane is divided in to windows or block of size 16*16 pixels. The segmented 2d difference image is partitioned in to non-overlapping rectangular regions of all white and mixed 16*16 blocks. Each partitioned block is transformed in to Boolean switching function in cubical form, treating the pixel values as a output of the function. Minimizing these switching functions using Quine- McCluskey minimization algorithm performs compression

    Potential Energy Curves and Dissociation Energies of Diatomic Indium Halides

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    Traditional fish processing in Odisha, India

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    The present study documents the traditional fish drying techniques used by the fisher folk communities of Bhadrak district, Odisha, India. Information on local knowledge and the use of different fish drying methods within the study area was collected from 72 fisher folk through semi-structured questionnaires, free interviews, informal conversations and direct observations. The results showed that sun drying was the most extensively used method for fish preservation. About 19.4% of the informants preferred to spread the fishes directly on earth, 34.8% on the mat, 5.5% on palm leaves, 29.2 % over bamboo bars and 11.2% followed interlocking of snouts/jaws on bamboo sticks. Almost all the fish drying devices are handmade with bamboo, wooden pole and sometimes nylon threads following traditional technologies. The quality of the dry fish could be improved by educating fishermen on hygiene, sanitation, use of good water quality and raw materials for processing. In this context, the low-cost solar dryer can be constructed by using locally available materials, thus preventing contamination and dependence on weather conditions. The dry fish production can play a crucial role in socio-economic upliftment, employment generation and poverty alleviation particularly to women as they depend on it directly for their livelihoods

    Construal Level Research in Decision Making: Analysis and Pushing Forward the Debate Using Bibliometric Review and Thematic Analysis

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    This study examines the extant literature on Construal Level Theory through bibliometric analysis that traces the path of research from 1998 to November 2019. It uses the Scopus database to identify emerging trends, seminal and most-cited papers, authors, universities, and countries that contributed to the development of the theory. A total of 680 papers from 1445 authors, were published in as many as 322 journals. The results indicate that ‘Journal of Experimental Social Psychology,’ ‘Journal of Personality and Social Psychology,’ and ‘Personality and Social Psychology Bulletin,’ were the three most productive sources of knowledge for this theory. The results show that over time, the discussion has progressed from theory to application in different areas of decision sciences, psychology, and management with a recent trend towards application in sustainability. This is the first literature review that has been conducted on the Construal Level Theory using bibliometric analysis. This study attempts to describe, explore possibilities, and provide a roadmap for future research in this field

    Mechanical Characterization of Monel 400 and 316 Stainless Steel Weldments

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    AbstractDissimilar combinations of Monel 400 and austenitic stainless steel AISI 316 is widely used in the petrochemical, nuclear industries where the weldments are usually subjected to hot corrosion. This paper deals with the assessment of metallurgical and mechanical properties of these bimetallic joints obtained by Gas Tungsten Arc Welding process using ERNiCrMo-3 filler metal. A detailed structure- property relationship was made on these bimetallic joints using the combined techniques of optical microscopy, SEM/EDAX analysis

    Inheritance of plumage colour in Japanese quails

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    A complete 4 × 4 diallel cross involving 4 quail populations, 2 of which possessed Pharao, plumage and other 2, White breasted and White plumage pattern was performed and the plumage colour of progeny in different crosses was recorded. The results indicated dominant nature of White breasted and the recessive nature of White feather colour mutations. The inheritance of plumage colours of Pharao, White breasted and White could be explained on the basis of two autosomal plumage color loci

    Comparative Evaluation of Dexmedetomidine and Magnesium Sulphate on Propofol Consumption, Haemodynamics and Postoperative Recovery in Spine Surgery: A Prospective, Randomized, Placebo Controlled, Double-blind Study

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    Purpose: Dexmedetomidine and magnesium sulfate have been used in anesthesia as adjuvant to provide hemodynamic stability and anesthetic agents sparing effect. We compared these effects of dexmedetomidine and magnesium sulfate in spine surgeries. Methods: Ninety patients were randomly assigned to three groups. Group D received dexmedetomidine loading dose 1 µg/kg over a period of 15 minutes and maintenance 0.5 µg/kg/h throughout the surgery. Group M received magnesium sulfate loading dose 50 mg/kg over a period of 15 minutes and maintenance 15 mg/kg/h throughout the surgery. Group C received same volume of normal saline. Heart rate (HR) and blood pressure values were recorded at various intervals. The induction and maintenance doses of anesthetics and recovery parameters were also recorded. Results: Heart rate in group D and group M were significantly decreased (p<0.05) during the whole intraoperative period compared to preoperative values. There was a significant difference in HR values between group C, D and M, during the whole intraoperaive period (p<0.05). Blood pressure values were statistically significantly lower in the group D and group M compared to group C after intubation and all time observations of surgery (p<0.05). Both drugs reduced the anesthetic agent’s requirement during surgery. However, the recovery parameters were statistically significant increase with magnesium sulphate compared to dexmedetomidine and control groups. Conclusion: Dexmedetomidine is more effective than magnesium sulfate for maintaining the hemodynamic stability in spine surgeries. Both these drugs also reduce the requirements of anesthetic agents. Recovery from dexmedetomidine is as rapid as control group compared to magnesium sulfate
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