32 research outputs found

    Common Bulkhead Tank Design for Cryogenic Stage of an Indian Launch Vehicle

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    Indian Space Research Organization (ISRO) has been advancing in space technology with its cost-effective techniques. Currently, ISRO, in its cryogenic stages, uses truss type intertank structure, which induces large concentrated loads at the truss interfaces. As a remedial measure, works on closed intertank are being carried out by them, but this configuration will considerably increase the launch vehicle mass compared to truss type. Therefore, after a thorough literature survey, a Common bulkhead (CBH) tank seemed to be the best solution to the aforementioned problem. Detailed research on sandwich-type CBH has been carried out in this paper with the motivation of saving mass and height in launch vehicles. Suitable core and facesheet material were selected. A novel foam-filled honeycomb core is suggested in this work. Several comparisons in various CBH dome designs were carried out to reach for the best possible configuration and composition that can be used. MATLAB®, SolidWorks®, and ANSYS® were used in parallel for all computations dealing with design and analysis. A mass saving of approximately upto 490 kgs and a height reduction of upto 1.755 m was obtained with the final selected configuration with respect to the current GSLV configuration. These savings can add extra payload capacity to ISRO launch vehicles in their future missions

    Study of instabilities and outbursts in luminous blue variables AF And &\& R 127

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    Luminous blue variables (LBVs) are evolved massive stars close to the Eddington limit, with a distinct spectroscopic and photometric variability having unsteady mass-loss rates. These stars show a considerable change in their surface temperature from quiescent to outbursts phase. The cause of irregular variability and unsteady mass-loss rate is not properly understood. Here we present the result of linear stability analysis in two LBVs AF And and R 127 during their quiescent and outburst phase. We note that several modes are unstable in the models of the considered LBVs. Mode interaction is frequent in the modal diagrams for the models of both LBVs. For AF And, number of instabilities increase in models having temperature below 15000 K. The found instabilities may be linked with the observed irregular variabilities and surface eruptions. Observational facilities of Belgo-Indian Network for Astronomy and Astrophysics (BINA) will be very beneficial to study the spectroscopic and photometric behavior of the considered LBVs.Comment: 7 pages, 3 figures, Proceedings paper of the third Belgo-Indian Network for Astronomy and Astrophysics (BINA) workshop, Accepted for publication in the Bulletin of Li\`ege Royal Society of Science

    A Hierarchical Framework of Challenges for Blockchain Adoption in Public Services. Implications for decision-makers

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    This study attempts to identify critical challenges for blockchain adoption in government, particularly public-service delivery in India, a developing country context. Through an extensive literature review and focus-group discussions with policymakers and blockchain experts, we have identified 12 adoption challenges for Blockchain in public service delivery. We then collected data and analysed using interpretive structural modeling and Cross-Impact Matrix Multiplication Applied to Classification (MICMAC) Analysis to develop a hierarchical framework of the challenges. Our findings indicate that governments must first ensure legislative support for blockchain-based transactions. This research contributes to information systems strategic planning literature and provides a framework for policymakers to craft a strategic approach to facilitate blockchain adoption

    On the optical properties of Ag^{+15} ion-beam irradiated TiO_{2} and SnO_{2} thin films

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    The effects of 200-MeV Ag^{+15} ion irradiation on the optical properties of TiO_{2} and SnO_{2} thin films prepared by using the RF magnetron sputtering technique were investigated. These films were characterized by using UV-vis spectroscopy, and with increasing irradiation fluence, the transmittance for the TiO_{2} films was observed to increase systematically while that for SnO_{2} was observed to decrease. Absorption spectra of the irradiated samples showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with increasing irradiation fluence for TiO_{2} while significant changes in the direct bandgap from 3.92 to 3.6 eV were observed for SnO_{2}. The observed modifications in the optical properties of both the TiO_{2} and the SnO_{2} systems with irradiation can be attributed to controlled structural disorder/defects in the system.Comment: 6 pages, ICAMD-201

    Risk of secondhand smoke exposure and severity of COVID-19 infection: multicenter case–control study

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    IntroductionExposure to secondhand smoke (SHS) is an established causal risk factor for cardiovascular disease (CVD) and chronic lung disease. Numerous studies have evaluated the role of tobacco in COVID-19 infection, severity, and mortality but missed the opportunity to assess the role of SHS. Therefore, this study was conducted to determine whether SHS is an independent risk factor for COVID-19 infection, severity, mortality, and other co-morbidities.MethodologyMulticentric case–control study was conducted across six states in India. Severe COVID-19 patients were chosen as our study cases, and mild and moderate COVID-19 as control were evaluated for exposure to SHS. The sample size was calculated using Epi-info version 7. A neighborhood-matching technique was utilized to address ecological variability and enhance comparability between cases and controls, considering age and sex as additional matching criteria. The binary logistic regression model was used to measure the association, and the results were presented using an adjusted odds ratio. The data were analyzed using SPSS version 24 (SPSS Inc., Chicago, IL, USA).ResultsA total of 672 cases of severe COVID-19 and 681 controls of mild and moderate COVID-19 were recruited in this study. The adjusted odds ratio (AOR) for SHS exposure at home was 3.03 (CI 95%: 2.29–4.02) compared to mild/moderate COVID-19, while SHS exposure at the workplace had odds of 2.19 (CI 95%: 1.43–3.35). Other factors significantly related to the severity of COVID-19 were a history of COVID-19 vaccination before illness, body mass index (BMI), and attached kitchen at home.DiscussionThe results of this study suggest that cumulative exposure to secondhand cigarette smoke is an independent risk factor for severe COVID-19 illness. More studies with the use of biomarkers and quantification of SHS exposure in the future are needed

    Artificial intelligence (AI): multidisciplinary perspectives on emerging challenges, opportunities, and agenda for research and practice

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    As far back as the industrial revolution, great leaps in technical innovation succeeded in transforming numerous manual tasks and processes that had been in existence for decades where humans had reached the limits of physical capacity. Artificial Intelligence (AI) offers this same transformative potential for the augmentation and potential replacement of human tasks and activities within a wide range of industrial, intellectual and social applications. The pace of change for this new AI technological age is staggering, with new breakthroughs in algorithmic machine learning and autonomous decision making engendering new opportunities for continued innovation. The impact of AI is significant, with industries ranging from: finance, retail, healthcare, manufacturing, supply chain and logistics all set to be disrupted by the onset of AI technologies. The study brings together the collective insight from a number of leading expert contributors to highlight the significant opportunities, challenges and potential research agenda posed by the rapid emergence of AI within a number of domains: technological, business and management, science and technology, government and public sector. The research offers significant and timely insight to AI technology and its impact on the future of industry and society in general

    Impact of osmotic stress on seed germination and seedling growth in black gram (Phaseolus mungo

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    Abstract: An experiment was conducted to see the impact of osmotic stress as it is one of the main cause in various soil and water disorders in agricultural field crops, specially the seed germination and seedling growth. The osmotic stress was generated using PEG-6000 and the seed germination, seedling growth were evaluated including the status of pigments i.e. chlorophyll (a, b and total), total carotenoids, pheophytin (a, b and total) and different enzymes like amylase, peroxidase, catalase and superoxide dismutase. The various osmotic potentials generated (-2, -5 and -10 bars) showed significant decrease in germination percentage as at the osmotic potential of -10 bars it was observed 70 in comparison to 90% of control. All the seedling growth parameter also showed inhibition with increase in osmotic potential. Increase in osmotic stress decreased Chlorophyll 'a', while Chlorophyll 'b' was increased in -5 bars while total chlorophyll showed decrease in -5 bars osmotic potential. Total carotenoids and pheophytin (a, b and total) were highly increased in -5 bars and decreased in -10 bars osmotic concentration. Enzymatic activity was found to be decreased in amylase while peroixidase, catalase and SOD were increased at different osmotic gradients in comparison to control. The data observed in the experiment can be helpful to assess the impact of any kind of osmotic stress on plant growth and development in crops

    Feasibility Study of Railway Line in Hilly Region using GIS

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    Aim of this study is to demonstrate the potential of GIS and multi-criteria decision approach (MCDA) as a tool for the selection of alignment of rail route in Hilly region. In the present study, Geographic information system (GIS) and multi-criteria decision approach (MCDA) is used to plan the alignment of railway route from Bhuntar to Kullu in Himachal Pradesh (HP), India. The various factors which affect the alignment of rail route are identified in this study. The factors considered in this study are topography, land-use, distance from power line, drainage pattern and road network of the area. The Analytical Hierarchy Process (AHP) is used to determine the ranking of the relative parameters. The determined ranking is used in pair-wise comparison to find the weights of these relative parameters. The maps with weighted parameters are overlaid and resultant map is created in GIS for route finding, station location and alignment of railway. The final map shows the cumulative effect of all the factors which affect the rail route alignment. The final map is divided into four parts based on feasibility index. It is found that 55% area is highly feasible for route alignment while 25% of the total area comes under category of low feasibility

    Performance Optimization using Fuzzy Modular Arithmetic in Short-Memory Scalar Multiplication for Koblitz Curve

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    It is widely recognized that data security, influence ofprocessor types used, resources and the architecture regardingthroughputs are playing a central role in IT systems. EllipticCurve Cryptography (ECC) is a sort of public-key cryptographythat is an alternative to other public-key algorithms like RSA,DSA. It is widely accepted because of the usage of smallerparameters than other public-key cryptosystems but with samelevel of security, reduces the memory consumption of hardwareand software by using the special kind of functionalities and animproved versions of algorithm with a larger margin of theprevious systems by using an extension of ECC called KoblitzCurve.It has becoming increasingly common to implementsuch kind of systems that takes a shorter computational time foran execution of an instruction. The previous versions were of anarithmetic computation that takes a longer time. I haveemphasized on fuzzy modular arithmetic that takes a veryshorter time towards the computational growth compared to thestandard one. I have also measured the performances in threesenses like theoretically, software and hardware perspective thatshows the evolution in the field of cryptograp
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