• 제목/요약/키워드: PANDA

검색결과 165건 처리시간 0.027초

Experimental assessment of thermal radiation effects on containment atmospheres with varying steam content

  • R. Kapulla;S. Paranjape;U. Doll;E. Kirkby;D. Paladino
    • Nuclear Engineering and Technology
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    • 제54권11호
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    • pp.4348-4358
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    • 2022
  • The thermal-hydraulics phenomena in a containment during an accident will necessarily include radiative heat transfer (i) within the gas mixture due to the high radiative absorption and emission of steam and (ii) between the gas mixture and the surrounding structures. The analysis of some previous PANDA experiments (PSI, Switzerland) demonstrated the importance of the proper modelling of radiation for the benefit of numerical simulations. These results together with dedicated scoping calculations conducted for the present experiments indicated that the radiative heat transfer is considerable, even for a very low amount of steam (≈2%). The H2P2 series conducted in the large-scale PANDA facility at the Paul-Scherrer-Institut (PSI) in the framework of the OECD/NEA HYMERES-2 project is intended to enhance the understanding of thermal radiation phenomena and to provide a benchmark for corresponding numerical simulations. Thus, the test matrix was tailored around the two opposite extremes: either gas compositions with small steam content such that radiative heat transfer phenomena can be neglected. Or gas mixtures containing larger amounts of steam, so that radiative heat transfer is expected to play a dominant role. The H2P2 series consists of 5 experiments designed to isolate the radiation phenomena from convective and diffusive effects as much as possible. One vessel with a diameter of 4 m and a height of 8 m was preconditioned with different mixtures of air / steam at room and elevated temperatures. This was followed by the build-up of a stable helium stratification at constant pressure in the upper part of the vessel. After that, helium was injected from the top into the vessel which leads to an increase of the vessel pressure and a corresponding elevation-dependent and transient rise of the gas temperature. It is shown that even the addition of small amounts of steam in the initial gas atmosphere considerably impacts the radiative heat transport throughout all phases of the experiments and markedly influences i) the monitored gas peak temperature, ii) the temperature history during the compression and iii) the following relaxation phase after the compression was stopped. These PANDA experiments are the first of its kind conducted in a large scale thermal-hydraulic facility.

A HIGHER ORDER ITERATIVE ALGORITHM FOR MULTIVARIATE OPTIMIZATION PROBLEM

  • Chakraborty, Suvra Kanti;Panda, Geetanjali
    • Journal of applied mathematics & informatics
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    • 제32권5_6호
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    • pp.747-760
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    • 2014
  • In this paper a higher order iterative algorithm is developed for an unconstrained multivariate optimization problem. Taylor expansion of matrix valued function is used to prove the cubic order convergence of the proposed algorithm. The methodology is supported with numerical and graphical illustration.

NONLINEAR FRACTIONAL PROGRAMMING PROBLEM WITH INEXACT PARAMETER

  • Bhurjee, A.K.;Panda, G.
    • Journal of applied mathematics & informatics
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    • 제31권5_6호
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    • pp.853-867
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    • 2013
  • In this paper a methodology is developed to solve a nonlinear fractional programming problem, whose objective function and constraints are interval valued functions. Interval valued convex fractional programming problem is studied. This model is transformed to a general convex programming problem and relation between the original problem and the transformed problem is established. These theoretical developments are illustrated through a numerical example.

AN ORDER LEVEL INVENTORY MODEL FOR PERISHABLE SEASONAL PRODUCTS WITH DEMAND FLUCTUATION

  • Panda, S.;Basu, M.
    • Journal of applied mathematics & informatics
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    • 제26권3_4호
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    • pp.615-625
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    • 2008
  • A single item order level inventory model for perishable products is considered in which a constant fraction of on hand inventory spoils per unit time. Demand linearly depends on time. The fluctuation of demand is taken into account to determine minimum total cost of the system. Both discrete and continuous fluctuations are considered. The model is developed and solved analytically for infinite time horizon. A numerical example is presented for finite time horizon. Sensitivity analysis of the model is carried out.

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A TRANSFORMATION FORMULA ASSOCIATED WITH THE GENERALIZED HYPERGEOMETRIC SERIES

  • Lee, Keumsik;Cho, Young-Joon;Seo, Tae-Young
    • 대한수학회논문집
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    • 제15권4호
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    • pp.707-714
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    • 2000
  • The authors aim at presenting a presumably new transformation formula involving generalized hypergeometric series by making use of series rearrangement technique which is one of the most effective methods for obtaining generating functions or other identities associated with (especially) the hypergeometric series. They also consider a couple of interesting special cases of their main result.

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Fractional Derivative Associated with the Multivariable Polynomials

  • Chaurasia, Vinod Bihari Lal;Shekhawat, Ashok Singh
    • Kyungpook Mathematical Journal
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    • 제47권4호
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    • pp.495-500
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    • 2007
  • The aim of this paper is to derive a fractional derivative of the multivariable H-function of Srivastava and Panda [7], associated with a general class of multivariable polynomials of Srivastava [4] and the generalized Lauricella functions of Srivastava and Daoust [9]. Certain special cases have also been discussed. The results derived here are of a very general nature and hence encompass several cases of interest hitherto scattered in the literature.

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Solubilization by $\beta$-Cyclodextrin: A Fluorescence Quenching Study

  • Panda, M.;Mishra, A.K.
    • Journal of Photoscience
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    • 제9권3호
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    • pp.75-79
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    • 2002
  • Solubility of carbon tetrachloride ($CCl_4$) in water increases appreciably in presence of $\beta$-cyclodextrin ($\beta$CD). $CCl_4$ is a very good quencher of 1-naphthol (1ROH) fluorescence. By studying the quenching of fluorescence of 1ROH included in $\beta$CD cavity, it was found that there is an increase in the availability of $CCl_4$ around $\beta$CD in the aqueous medium. This could help to rationalize the enhanced solubility of $CCl_4$.

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Peroxy Acid Oxidations: A Kinetic and Mechanistic Study of Oxidative Decarboxylation of $\alpha$-Keto Acids by Peroxomonophosphoric Acid

  • Radhasyam Panda
    • Bulletin of the Korean Chemical Society
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    • 제22권8호
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    • pp.909-913
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    • 2001
  • The kinetics of oxidative decarboxylation of pyruvic acid and benzoylformic acid by peroxomonophosphoric acid (PMPA) in aqueous medium have been investigated. The reaction follows second order-first order each in PMPA and substrate concentration a t constant pH. The reactivity of different peroxo species in the oxidation has been determined. Activation energy and thermodynamic parameters have been computed. A plausible mechanism consistent with the observed results is proposed.