2,837 research outputs found

    Mathematical Modelling of Shaft based direct Reduction processes of Iron manufacture with Recirculation of Moisture free flue Gases

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    Shaft furnaces account for over 80 percent of the world production of the directly reduced iron that is fed' to an electric arc- furnace as an alternative to the blast furn-ace basic oxygen steelmaking route. The process is charac-terised by high rates of production as well as high deg-rees of metallisation of the product for its economic melting in the electric arc furnace for its survival in the present day competitive world. This is best done by keeping the amount of hot reducirig gases such as CO and H2 well above the theoretical minimum as the same would tend to ensure rapid preheating of the incoming uniformly sized burdan materials and the accompanying high rates of Iron ore reduction . The unutilised portions of CO and H, in the flue gates are partly recycled back to the furnace through a reformer where CO2 in flue gases is used to conve, the natural gas into CO and H2 at around 10000, and partly used as fuel tc. meet. the energy requirements of the reformer. As the flue gases are to be cooled to get rid of the dust particles, most of the water vapours, present in the gases a5 a result of reduction of iron ore by hydrogen in the shaft, are removed by condensatio

    D-Terms, Unification, and the Higgs Mass

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    We study gauge extensions of the MSSM that contain non-decoupling D-terms, which contribute to the Higgs boson mass. These models naturally maintain gauge coupling unification and raise the Higgs mass without fine-tuning. Unification constrains the structure of the gauge extensions, limiting the Higgs mass in these models to roughly less than 150 GeV. The D-terms contribute to the Higgs mass only if the extended gauge symmetry is broken at energies of a few TeV, leading to new heavy gauge bosons in this mass range.Comment: 30+1 pages, 7 figure

    The number of privately treated tuberculosis cases in India: an estimation from drug sales data

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    Background Understanding the amount of tuberculosis managed by the private sector in India is crucial to understanding the true burden of the disease in the country, and thus globally. In the absence of quality surveillance data on privately treated patients, commercial drug sales data offer an empirical foundation for disease burden estimation. Methods We used a large, nationally representative commercial dataset on sales of 189 anti-tuberculosis products available in India to calculate the amount of anti-tuberculosis treatment in the private sector in 2013–14. We corrected estimates using validation studies that audited prescriptions against tuberculosis diagnosis, and estimated uncertainty using Monte Carlo simulation. To address implications for numbers of patients with tuberculosis, we explored varying assumptions for average duration of tuberculosis treatment and accuracy of private diagnosis. Findings There were 17·793 million patient-months (95% credible interval 16·709 million to 19·841 million) of anti-tuberculosis treatment in the private sector in 2014, twice as many as the public sector. If 40–60% of private-sector tuberculosis diagnoses are correct, and if private-sector tuberculosis treatment lasts on average 2–6 months, this implies that 1·19–5·34 million tuberculosis cases were treated in the private sector in 2014 alone. The midpoint of these ranges yields an estimate of 2·2 million cases, two to three times higher than currently assumed. Interpretation India's private sector is treating an enormous number of patients for tuberculosis, appreciably higher than has been previously recognised. Accordingly, there is a re-doubled need to address this burden and to strengthen surveillance. Tuberculosis burden estimates in India and worldwide require revision

    Geometry of Scheduling on Multiple Machines

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    We consider the following general scheduling problem: there are m identical machines and n jobs all released at time 0. Each job j has a processing time pj, and an arbitrary non-decreasing function fj that specifies the cost incurred for j, for each possible completion time. The goal is to find a preemptive migratory schedule of minimum cost. This models several natural objectives such as weighted norm of completion time, weighted tardiness and much more. We give the first O(1) approximation algorithm for this problem, improving upon the O(loglognP) bound due to Moseley (2019). To do this, we first view the job-cover inequalities of Moseley geometrically, to reduce the problem to that of covering demands on a line by rectangular and triangular capacity profiles. Due to the non-uniform capacities of triangles, directly using quasi-uniform sampling loses a O(loglogP) factor, so a second idea is to adapt it to our setting to only lose an O(1) factor. Our ideas for covering points with non-uniform capacity profiles (which have not been studied before) may be of independent int

    Z-prime Gauge Bosons at the Tevatron

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    We study the discovery potential of the Tevatron for a Z-prime gauge boson. We introduce a parametrization of the Z-prime signal which provides a convenient bridge between collider searches and specific Z-prime models. The cross section for p pbar -> Z-prime X -> l^+ l^- X depends primarily on the Z-prime mass and the Z-prime decay branching fraction into leptons times the average square coupling to up and down quarks. If the quark and lepton masses are generated as in the standard model, then the Z-prime bosons accessible at the Tevatron must couple to fermions proportionally to a linear combination of baryon and lepton numbers in order to avoid the limits on Z--Z-prime mixing. More generally, we present several families of U(1) extensions of the standard model that include as special cases many of the Z-prime models discussed in the literature. Typically, the CDF and D0 experiments are expected to probe Z-prime-fermion couplings down to 0.1 for Z-prime masses in the 500--800 GeV range, which in various models would substantially improve the limits set by the LEP experiments.Comment: 34 pages, 13 figure

    Multi-Channel Transport in Disordered Medium under Generic Scattering Conditions

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    Our study of the evolution of transmission eigenvalues, due to changes in various physical parameters in a disordered region of arbitrary dimensions, results in a generalization of the celebrated DMPK equation. The evolution is shown to be governed by a single complexity parameter which implies a deep level of universality of transport phenomena through a wide range of disordered regions. We also find that the interaction among eigenvalues is of many body type that has important consequences for the statistical behavior of transport properties.Comment: 19 Pages, No Figure

    The New Fat Higgs: Slimmer and More Attractive

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    In this paper we increase the MSSM tree level higgs mass bound to a value that is naturally larger than the LEP-II search constraint by adding to the superpotential a λSHuHd\lambda S H_{u}H_{d} term, as in the NMSSM, and UV completing with new strong dynamics {\it before} λ\lambda becomes non-perturbative. Unlike other models of this type the higgs fields remain elementary, alleviating the supersymmetric fine-tuning problem while maintaining unification in a natural way.Comment: 14 pages and 2 figures. Added references and updated argument about constraints from reheating temperatur

    Environmental Evaluation and Global Development Institutions

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    Evaluation is increasingly important for finding sustainable solutions for the people and the planet, based on a systematic analysis of what works, for whom, and under what circumstances, and to contribute to the achievement of the Sustainable Development Goals, as they pertain to the environment. This book explores why the Global Environment Facility (GEF) invests in evaluation for accountability and learning to inform its decision-making on programming priorities, and how this leads to wiser funding decisions and better program performance on the ground. The book is based on real-life experiences of how to make evaluation count for international environmental action. Drawing upon comprehensive evaluations of the GEF, it provides unique insights from authors responsible for designing, implementing, and disseminating the findings of the evaluations. No other multilateral development or environment agency places evaluation fully at the center of their decision-making. The book outlines the trends in the global environment and the changing landscape of international environmental finance. It defines the role of the GEF and explains its institutional framework and the unique partnership that involves donor and recipient countries, multilateral development banks, UN agencies, nongovernmental organizations (NGOs), and national agencies in the developing countries. Further, it provides useful pointers to other organizations wishing to enhance evidence-based decision-making for improving their relevance, performance, and impact. The book will be most suitable for graduate-level, specialized study in a variety of disciplines such as environmental and development economics, political science, international relations, geography, sociology, and social anthropology
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