538 research outputs found

    Effect of Shot Peening Process on Rolling Contact Fatigue Performance of EN 31 Alloy Steel

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    This paper aims to study the effect of shot peening on the Rolling Contact Fatigue (RCF) life of EN 31 Steel subjected to a pure rolling condition. Tests were carried out under lubricated contact conditions using a two-disc on-cylinder test rig. The orthogonal stress distributions and depth of deformation zones under static loading conditions were calculated using an elastic model by Finite Element Analysis (FEA) method. Shot peening increased the surface hardness by 20 % and imparted residual stress, which resulted in a 2-fold improvement of life. The depth of origin of the crack from the sub-surface was found to be in good agreement with the depth of maximum shear region obtained from the finite element model

    Convergence Rates in L^2 for Elliptic Homogenization Problems

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    We study rates of convergence of solutions in L^2 and H^{1/2} for a family of elliptic systems {L_\epsilon} with rapidly oscillating oscillating coefficients in Lipschitz domains with Dirichlet or Neumann boundary conditions. As a consequence, we obtain convergence rates for Dirichlet, Neumann, and Steklov eigenvalues of {L_\epsilon}. Most of our results, which rely on the recently established uniform estimates for the L^2 Dirichlet and Neumann problems in \cite{12,13}, are new even for smooth domains.Comment: 25 page

    Postmastectomy chest wall radiation of left-sided carcinoma breast - a dosimetric comparison between electrons and photons

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    Background: For carcinoma breast patients requiring post mastectomy radiation therapy (PMRT), tangential photon beam (PB) is commonly used technique. The physical nature of electrons results in sharp dose fall off and reduces organs at risk (OAR) doses. Aim of the present study is to compare the coverage of chest wall and doses received by OARs – heart and lung between electron and photon beam plans in left sided breast cancer patients requiring PMRT.Methods: This study was done in 22 left sided carcinoma breast patients treated at GSL Medical College between May to December 2017. Both tangential PB plans and electron beam (EB) plans were generated on simulation computed tomography (CT) for each patient and both plans were compared. A dose of 50 Gy was prescribed to planning target volume (PTV) in 25 fractions.Results: The PB plans provided superior homogeneity index (HI) and conformity index CI compared to the EB plans (p<0.05). There was significant difference in favour of electron-beam plans for mean heart dose (p=0.0312), V25 Gy (p=0.029), V45 Gy (p=0.001) and V20 Gy of left lung (p=0.042). There was no significant difference in mean lung dose.Conclusions: Dosimetric data from this study suggests that PMRT with the electron beam can reduce doses to the heart and left lung with acceptable target coverage. It needs further research in the clinical setting

    Catalytic Social Entrepreneurship to Combat Desperate Poverty: A Systems Approach

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    Any credible agenda that seeks to eradicate global poverty must seek to correct the structural injustices and inequities that cause and perpetuate desperate endemic poverty. Such an agenda must aim not merely to aid the poor with grants, welfare and subsidies, but it must primarily seek to enhance the capabilities, skills, access and opportunities of the marginalized to participate on more equitable terms, in the dynamic process of overall economic growth. We apply a systems approach to poverty, the latter itself being a pernicious system. Eradication of global desperate poverty and its unjust structural causes can be done through two concurrent systems-thinking based strategies: (a) micro catalytic social entrepreneurship that leads to catalytic innovations that alleviate poverty, and (b) macro social catalytic political entrepreneurship that radically innovates legislation or designs macro-policy intervention systems that can effectively dismantle existing unjust structures of social injustice and inequities – the causes that perpetuate endemic global poverty. Using the theories of catalytic innovations and the bottom of the pyramid, we focus on solution (a) as being feasible, viable and doable and in the long run having the potential for eradicating global desperate poverty. We also provide two case studies where solution (b) was effectively implemented. The main proposition of the paper is that the use of both micro- and macro- catalyst can help alleviate poverty in the world.   Keywords: Micro catalyst, macro catalyst, global poverty, system approach, catalytic innovation, macro-policy intervention

    A Visual Analytics Framework for Reviewing Streaming Performance Data

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    Understanding and tuning the performance of extreme-scale parallel computing systems demands a streaming approach due to the computational cost of applying offline algorithms to vast amounts of performance log data. Analyzing large streaming data is challenging because the rate of receiving data and limited time to comprehend data make it difficult for the analysts to sufficiently examine the data without missing important changes or patterns. To support streaming data analysis, we introduce a visual analytic framework comprising of three modules: data management, analysis, and interactive visualization. The data management module collects various computing and communication performance metrics from the monitored system using streaming data processing techniques and feeds the data to the other two modules. The analysis module automatically identifies important changes and patterns at the required latency. In particular, we introduce a set of online and progressive analysis methods for not only controlling the computational costs but also helping analysts better follow the critical aspects of the analysis results. Finally, the interactive visualization module provides the analysts with a coherent view of the changes and patterns in the continuously captured performance data. Through a multi-faceted case study on performance analysis of parallel discrete-event simulation, we demonstrate the effectiveness of our framework for identifying bottlenecks and locating outliers.Comment: This is the author's preprint version that will be published in Proceedings of IEEE Pacific Visualization Symposium, 202

    Phi-Meson Production at RHIC, Strong Color Fields and Intrinsic Transverse Momenta

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    We investigate the effects of strong color fields and of the associated enhanced intrinsic transverse momenta on the phi-meson production in ultrarelativistic heavy ion collisions at RHIC. The observed consequences include a change of the spectral slopes, varying particle ratios, and also modified mean transverse momenta. In particular, the composition of the production processes of phi mesons, that is, direct production vs. coalescence-like production, depends strongly on the strength of the color fields and intrinsic transverse momenta and thus represents a sensitive probe for their measurement.Comment: 4 pages, 3 figure

    Nanomedicine: towards development of patient-friendly drug-delivery systems for oncological applications

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    The focus on nanotechnology in cancer treatment and diagnosis has intensified due to the serious side effects caused by anticancer agents as a result of their cytotoxic actions on normal cells. This nonspecific action of chemotherapy has awakened a need for formulations capable of definitive targeting with enhanced tumor-killing. Nanooncology, the application of nanobiotechnology to the management of cancer, is currently the most important area of nanomedicine. Currently several nanomaterial-based drug-delivery systems are in vogue and several others are in various stages of development. Tumor-targeted drug-delivery systems are envisioned as magic bullets for cancer therapy and several groups are working globally for development of robust systems

    On a (\beta,q)-generalized Fisher information and inequalities involving q-Gaussian distributions

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    In the present paper, we would like to draw attention to a possible generalized Fisher information that fits well in the formalism of nonextensive thermostatistics. This generalized Fisher information is defined for densities on Rn.\mathbb{R}^{n}. Just as the maximum R\'enyi or Tsallis entropy subject to an elliptic moment constraint is a generalized q-Gaussian, we show that the minimization of the generalized Fisher information also leads a generalized q-Gaussian. This yields a generalized Cram\'er-Rao inequality. In addition, we show that the generalized Fisher information naturally pops up in a simple inequality that links the generalized entropies, the generalized Fisher information and an elliptic moment. Finally, we give an extended Stam inequality. In this series of results, the extremal functions are the generalized q-Gaussians. Thus, these results complement the classical characterization of the generalized q-Gaussian and introduce a generalized Fisher information as a new information measure in nonextensive thermostatistics.Comment: v2: corrected equation (A5
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