91 research outputs found

    Optimization of production parameters in sms plant, welspun

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    Welspun Steel Limited produces steel billets of various dimensions 30% of which are sent to produce Re-bars. WSL’s TMT is presently the second best TMT available for business and industry based constructions in the market after JINDAL’s. As per the Welspun Fellowship Program, the student has undergone a training period alongside doing the project in optimizing the production of the WSL plant in Anjar, Gujarat. The thesis details the findings and discusses the current issues that a typical secondary steel industry, namely WSL, is facing along with some theoretical suggestions. DRI + Scrap is the raw material in the secondary steel production in WSL. A conclusive study is conducted to check the tap times, just by melting DRI without the steel scrap. The results indicate a success and so a new method, posing a new set of problems though, to be experimented and researched on. Finally, sets of loopholes, neglected zones and bottlenecks have been identified all through the process of steel making and casting. Suggestions have been insisted and some of them were effectively implemented

    Contribution-based priority assessment in a web-based intelligent argumentation network for collaborative software development

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    Decision making is an important aspect of the collaborative software development process which usually involves complex process of conflict resolution. Stakeholders approach decision making process from multiple perspectives and their priorities play a vital role in it. The priority assessment methods used in the argumentation process so far are usually static. Priorities remain constant throughout the decision making process. In order to make the collaborative system more closely replicate real-world scenarios, this work incorporates dynamic priority assessment into a web-based collaborative system which is based on intelligent computational argumentation. It evaluates priorities dynamically for each cycle of decision process based on contribution of individual participant. The contribution is assessed based on the impact of each participant\u27s arguments on a winning design alternative. More successful participants have higher priorities in argumentations during collaboration. An empirical case study is conducted to evaluate effectiveness of dynamic priority assessment in improving quality of the argumentation based decision making --Abstract, page iii

    Algorithm to Obtain Total Order from Partial Orders for Social Networks

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    We developed an algorithm for generating total orders from partial orders based on a variant of QuickSort. We also constructed a website: 100 best movies! that would generate and display the total order of the best 100 movies from partial orders that are humanly ordered and stored in a database. The users of the website can add new movies of different categories to the database. The users can also generate partial rankings within specific categories. The total order of 100 best movies! would be calculated from the humanly computed partial orders stored in the database

    FRAMEWORK FOR IMPROVING PERFORMANCE OF PROTOCOLS FOR READING RADIO FREQUENCY IDENTIFICATION TAGS

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    Radio-frequency Identification (RFID) is a highly sought-after wireless technology used to track and manage inventory in the supply chain industry. It has varied applications ranging from automated toll collection and security access management to supply chain logistics. Miniaturization and low tag costs of RFID tags have lead to item-level tagging, where not just the pallet holding products is tagged but each product inside has a tag attached to it. Item-level tagging of goods improves the accuracy of the supply chain but it significantly increases the number of tags that an RFID reader must identify and track. Faster identification is crucial to cutting cost and improving efficiency. Existing RFID protocols were designed to primarily handle static scenarios with both RFID tags and readers not being in motion. This research addresses the problem of inventory tracking within a warehouse in multitude of scenarios that involves mobile tags, multiple readers and high density environments. Mobility models are presented and frameworks are developed for the following scenarios: a) mobile tags on a conveyor belt with multiple fixed readers; b) mobile reader in a warehouse with stationary tags in shelves; and c) high density tag population with Near-Field (NF) communication. The proposed frameworks use information sharing among readers to facilitate protocol state handoff and segregation of tags into virtual zones to improve tag reading rates in mobile tag and mobile reader scenarios respectively. Further, a tag’s ability to listen to its Near-Field neighboring tags transmissions is exploited to assist the reader in resolving collisions and hence enhancing throughput. The frameworks discussed in this research are mathematically modeled with a probabilistic analysis of protocols employed in conjunction with framework. With an increased number of tags to be identified, mathematically understanding the performance of the protocol in these large-scale RFID systems becomes essential. Typically, this analysis is performed using Markov-chain models. However, these analyses suffer from the common state-space explosion problem. Hence, it is essential to come up with a scalable analysis, whose computation model is insensitive to the number of tags. The following research analyzes the performance of tag identification protocols in highly dense tag scenarios, and proposes an empirical formula to estimate the approximate time required to read all the tags in a readers range without requiring protocol execution

    The need for obscured supermassive black hole growth to explain quasar proximity zones in the epoch of reionization

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    Proximity zones of quasars with redshifts z6z \gtrsim 6 are unique probes of the growth of supermassive black holes. But simultaneously explaining proximity zone sizes and black hole masses at this redshift has proved to be challenging because of the very short quasar lifetimes implied by the proximity zones. We study the robustness of some of the assumptions that are usually made to infer quasar lifetimes from proximity zone sizes. We show that thanks to the short equilibration time of gas inside the proximity zones, small proximity zones can be readily explained by quasars that vary in brightness with a short duty cycle of fduty0.1f_\mathrm{duty}\sim 0.1 and short bright periods of ton104t_\mathrm{on}\sim 10^4 yr, even for long lifetimes. We further show that reconciling this with black hole mass estimates requires the black hole to continue to grow and accrete during its obscured phase. The consequent obscured fractions of \gtrsim 0.7 or higher are consistent with low-redshift measurements and models of black hole accretion. Further, the large dynamic range of our simulation, and its calibration to the Lyman-α\alpha forest, allows us to investigate the influence of the large-scale topology of reionization and the quasar's host halo mass on proximity zones. We find that incomplete reionization can impede the growth of proximity zones and make them smaller up to 30%, but the quasar host halo mass only affects proximity zones weakly and indirectly. Our work suggests that high-redshift proximity zones can be an effective tool to study quasar variability and black hole growth.Comment: 19 pages, 17 figures, submitted to MNRAS, comments welcom

    Evaluation of Physical and Chemical Pretreatment Methods to Improve Efficiency of Anaerobic Digestion of Waste Streams from Grain Processing

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    Globally, Anaerobic Digestion (AD) industry is booming and biogas, the most sustainable biofuel, produced via AD is in an exponential market growth curve. According to a November 2020 report from US Energy Information Administration (EIA), “25 large dairies and livestock operations in the United States produced a total of about 224 million kWh (or 0.2 billion kWh) of electricity from biogas”. However, the growth of AD and the cost-effective use of the generated biogas are hindered by the inconsistencies (composition, suspended solids, flow rate, etc.) of the incoming waste stream and the associated biogas quality (due to the presence of hydrogen sulfide gas). A pretreatment step prior to an AD unit can promote consistency in the incoming stream, minimize the suspended solids; and thereby insures the efficiency of AD. In this study, we evaluated the method of pretreatment of waste streams from three grain processing industries, where 1) we adjusted the pH of a stream corresponding to its isoelectric point (zero zeta-potential), 2) removed solids (and their corresponding COD) that precipitated, and 3) produced a consistent composition stream to feed the AD process. For grain processing industry, the precipitated solids can be returned to their process – thus integrating the pretreatment with the rest of the process. The pH pre-treatment should not add any additional cost to the plant since the pH of the waste streams from grain processing plant needs to be raised per plant permits prior to disposal. Our lab and pilot AD studies showed a positive effect of such pretreatment on these waste streams in terms of increased biogas production (11–60%) and COD removal (12–60%), and in some instances reduction in H2S content in biogas (8%). This study clearly demonstrated that such a pretreatment method is economical and is effective to improve AD performance on waste waters from grain processing industries

    Control of the growth interface location and morphology in vertical Brigman geometries

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1996.Includes bibliographical references (leaves 161-164).by Satyavolu Srinivas Papa Rao.Ph.D

    Robustness of direct measurements of the mean free path of ionizing photons in the epoch of reionization

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    Measurements of the mean free path of Lyman-continuum photons in the intergalactic medium during the epoch of reionization can help constrain the nature of the sources as well as sinks of hydrogen-ionizing radiation. A recent approach to this measurement has been to utilize composite spectra of multiple quasars at z6z\sim 6, and infer the mean free path after correcting the spectra for the presence of quasar proximity zones. This has revealed not only a steep drop in the mean free path from z=5z=5 to z=6z=6, but also potentially a mild tension with reionization simulations. We critically examine such direct measurements of the mean free path for biases due to quasar environment, incomplete reionization, and quasar proximity zones. Using cosmological radiative transfer simulations of reionization combined with one-dimensional radiative transfer calculations of quasar proximity zones, we find that the bias in the mean free path due to overdensities around quasars is minimal at z6z\sim 6. Patchiness of reionization at this redshift also does not affect the measurements significantly. Fitting our model to the data results in a mean free path of λmfp=0.900.40+0.66\lambda_{\mathrm{mfp}}=0.90^{+0.66}_{-0.40} pMpc at z=6z=6, which is consistent with the recent measurements in the literature, indicating robustness with respect to the modelling of quasar proximity zones. We also compare various ways in which the mean free path has been defined in simulations before the end of reionization. Overall, our finding is that recent measurements of the mean free path appear to be robust relative to several sources of potential bias.Comment: 10 pages, 9 figures, submitted to MNRA

    Integration of InP and InGaAs on 300 mm Si wafers using chemical mechanical planarization

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    Integration of III-V high mobility channel materials in complementary metal oxide semiconductors (CMOS) and III-V photonic materials for integrated light sources on Si substrates requires low defect density III-V buffer layers in order to enable epitaxial growth of high crystal quality active layers. For the fabrication of In0.53Ga0.47As n-channel MOSFET on Si, a lattice matched InP buffer layer is one of the most effective approaches when used in combination with the aspect ratio trapping technique, an integration method known for reducing the density of defects formed during relaxation of strain induced by the lattice mismatch between InP and Si. The InP buffer should be planarized in order to improve thickness uniformity and roughness before subsequent deposition of active layers. In this work we discuss the development of InP planarization on 300 mm Si wafers and investigate slurry composition effects on the final oxide loss and condition of the InP surface. To further explore viability of this approach we deposited an epitaxial In0.53Ga0.47As n-MOS channel layer on top of the planarized InP buffer
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