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Baltateanu D.M.,West University of Timisoara | Satulu S.S.,West University of Timisoara | Birau V.,Theoretical High School J. L. Calderon
Physica Scripta | Year: 2013

We propose a computational model for obtaining the transmission coefficient of a relativistic electron transported through a semiconductor-based multiple quantum well structure, in the presence of an external, constant electric field. For this purpose, a relativistic version of the transfer matrix formalism for piecewise constant potentials, based on the Dirac equation, is used. The effects of the electric field and geometry on the relativistic transmission coefficient are investigated. The results obtained in the relativistic framework are compared with the non-relativistic ones. This model could be used in problems with polarization and point-dependent effective mass, with possible applications to the field of optoelectronic devices. © 2013 The Royal Swedish Academy of Sciences. Source


Rinovetz A.,Sudan University of Science and Technology | Rinovetz Z.A.,Theoretical High School J. L. Calderon | Mateescu C.,Sudan University of Science and Technology | Trasca T.-I.,Sudan University of Science and Technology | And 2 more authors.
Journal of Food, Agriculture and Environment | Year: 2011

Present technological opportunities (fractionation, hydrogenation, interesterification) allow the proper chemical and/or physicochemical "changing" of glycerides according to the goal aimed at. The heterogeneous character of natural fats determines the physical features and their rheological behaviour before and after processing. Dry fractionation - one of the "cleanest" procedures of managing separation into more defined liquid/solid lipid fractions from the initial mixture - has been constantly optimised through the development of techniques of physical and mechanical separation (filtering, centrifugation, refrigeration) and of fractioned crystallisation. Correlating the rheological behaviour with lipidic structures is, generally, more difficult, since most of them change their rheological features depending on operating parameters over the duration of the processing without corresponding chemical changes. In this paper we assess the rheological behaviour of pork lards (raw material) and of liquid (FL)/solid lipid (FS) fractions as a result of the dry fractionation process through centrifugation corroborated with temperature monitoring. Results confirm the way to obtain similar products with physical feature different from the initial material, with possible late guided accession in the field of foods. Source


Rinovetz A.,Sudan University of Science and Technology | Jianu C.,Sudan University of Science and Technology | Rinovetz A.,Theoretical High School J. L. Calderon | Iancu T.,Sudan University of Science and Technology | And 3 more authors.
Journal of Food, Agriculture and Environment | Year: 2011

This paper resumes the series of studies concerning the separation of lipid mixtures from pork lard through the method of dry fractionation, more exact temperature of the operating. The changes the authors introduced improved the efficiency of isolation of solid fractions from liquid (fluid) ones through the inclusion of an opalescent intermediary layer (medium-melting point fraction) (MMPF) in repeated separations. Source


Rinovetz A.,Sudan University of Science and Technology | Jianu C.,Sudan University of Science and Technology | Rinovetz Z.A.,Theoretical High School J. L. Calderon | Berbentea F.,Sudan University of Science and Technology | And 3 more authors.
Journal of Food, Agriculture and Environment | Year: 2011

This paper presents trial results of the study of replicated dry fractionation of the medium melting point-fraction (MMPF) of pork lard purified of sterols and lecithin together with a change of centrifugation time and speed at 8°C. The importance of MMPF is thus again confirmed as a more difficult separation area because of the presence, under real working conditions, of several compounds with colloidal features opposing the fractionation. Source

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