Showing papers by "University of Maribor published in 1990"
TL;DR: In this article, an automated implementation of the modelling/decomposition (M/D) strategy by Kocis and Grossmann (Computers chem. Engng 13, 797-819, 1989) for the MINLP optimization of process flowsheets is presented.
90 citations
TL;DR: In this paper, it was shown that the existence of symmetric bi-derivation on a prime ring of characteristic different from two and three, such that the mappingx → D(x, y) is a derivation, for any fixedy ∈ R, then eitherD1 = 0 orD2 = 0.
Abstract: LetR be a ring. A bi-additive symmetric mappingD(.,.): R × R → R is called a symmetric bi-derivation if, for any fixedy ∈ R, the mappingx → D(x, y) is a derivation. The purpose of this paper is to prove two results concerning symmetric bi-derivations on prime rings. The first result states that, ifD1 andD2 are symmetric bi-derivations on a prime ring of characteristic different from two and three such thatD1(x, x)D2(x,x) = 0 holds for allx ∈ R, then eitherD1 = 0 orD2 = 0. The second result proves that the existence of a nonzero symmetric bi-derivation on a prime ring of characteristic different from two and three, such that [[D(x, x),x],x] ∈ Z(R) holds for allx ∈ R, whereZ(R) denotes the center ofR, forcesR to be commutative.
46 citations
TL;DR: A variant of the Green's function nodal method derived from the boundary integral form of the multigroup neutron diffusion equation in rectangular geometry, which is attractive to design highly efficient algorithms for a large mainframe, a personal computer or a parallel processor.
Abstract: A variant of the Green's function nodal method derived from the boundary integral form of the multigroup neutron diffusion equation in rectangular geometry is presented. As usual in the nodal methods, the multi-dimensional diffusion equation is integrated in the transverse direction. The resulting 1D diffusion equation is solved following the Boundary Element technique in one dimension. In this way a weighted residual method is obtained, with a Green's function for weighting, but with different boundary conditions than normally applied in the Green's function nodal methods. Mathematical formulation of the method is given and the iteration procedure is described. A computer program BINDIF has been designed, based on the new method. Its capabilities include the solution of the multigroup neutron diffusion equation of 1D, 2D and 3D rectangular lattices. The BINDIF program has been checked against other methods used for global reactor calculations on benchmark problems, representative of realistic power reactor cores. The results indicate that the method is attractive to design highly efficient algorithms for a large mainframe, a personal computer or a parallel processor.
12 citations
TL;DR: In this paper, the preparation and usability of a sulphide ion-selective microelectrode, prepared by chemical pretreatment of silver wire with Hg2+ and sulphidization in alkaline sulphide solution is described.
Abstract: The preparation and usability of a sulphide ion-selective microelectrode, prepared by chemical pretreatment of silver wire with Hg2+ and sulphidization in alkaline sulphide solution is described. The electrode is suitable for direct potentiometric measuring of sulphide in alkali solutions of concentrations down to 4×10−7 mol/l. It can be used for the potentiometric measurement of various thiocompounds in alkali and neutral media. The 15 min required for each chemical treatment are enough for the preparation of the described electrode.
8 citations
TL;DR: In this article, the incoherent scattering law for the model of the uniaxial, molecular stochastic reorientation within an arbitrary apex angle Ф0 has been calculated.
Abstract: On the basis of the solution of the random flight problem of a particle between two perfectly reflecting potential barriers the incoherent scattering law for the model of the uniaxial, molecular stochastic reorientation within an arbitrary apex angle Ф0 has been calculated. In conjunction with the published NMR results evidence is presented, that the along the long axis uniaxial rotation, can be described in terms of the model with an apex angle φ0 of 57°. The model of the restricted uniaxial reorientation, which is expected to be of interest in nematic phases of biaxial molecules, has been applied to the investigation, by quasi elastic incoherent cold neutron scattering, of the rotational dynamics of the rigid benzylidene central part of a magnetically oriented MBBA sample in the nematic phase at 303 K.
7 citations
10 Dec 1990-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a gamma spectrometric technique was developed with the aim of determining the amount of a certain radioactive fission product taking into consideration local variations of the linear attenuation coefficient of gamma rays.
Abstract: A description is given of a gamma spectrometric technique which has been developed with the aim of determining the amount of a certain radioactive fission product taking into consideration local variations of the linear attenuation coefficient of gamma rays. Also, an experiment using a fuel element of the TRIGA Mark II reactor in Ljubljana is presented.
6 citations
TL;DR: In this paper, the energy level spectrum for a system of four interacting methyl groups belonging to an X(CH3)4 type molecule is calculated by numerical methods, and the rotational potential at the site of each methyl group is assumed to be of a three-fold symmetry.
Abstract: The energy level spectrum for a system of four interacting methyl groups belonging to an X(CH3)4 type molecule is calculated by numerical methods. The rotational potential at the site of each methyl group is assumed to be of a three-fold symmetry. The torsion-torsion interaction is defined as a term in the multipole expansion of the electrostatic interaction of two rigid charge distributions. It is shown, that the tunneling frequency characterizing the ground state manifold in the absence of methyl-methyl interaction, splits into a set of closely spaced frequencies.
6 citations
TL;DR: The subsequent three papers in the present volume (viz. Snedec', Teržan's, and Trobevsek-Drobnak's) arise from the research in historical syritax conducted since 1986 by us in the Department for Germanic Languages and Literatures of the University of Ljubljana, Yugoslavia, under the advisorship of J. Oresnik as mentioned in this paper.
Abstract: The subsequent three papers in the present volume (viz. Snedec', Teržan's, and Trobevsek-Drobnak's) have arisen from the research in historical syritax conducted since 1986 by us in the Department for Germanic Languages and Literatures of the University of Ljubljana, Yugoslavia, under the advisorship of J. Oresnik.
5 citations
TL;DR: The DFCL — a relatively low level data-flow language and a complier, which transforms programs written in this language into program graphs with different levels of granularity are presented and it is pointed out that it is a viable candidate for future industrial controllers.
2 citations
TL;DR: In this article, the authors focus on the elementary school, trying to give an overview of the main school reforms which have taken place since the Second World War and their political background, and the developments to be expected in schools in the near future as a result of our changing society.
Abstract: As is the case in many countries, education in Yugoslavia can be divided into three levels: elementary, secondary and university level. This paper will focus on the elementary school, trying to give an overview of the main school reforms which have taken place since the Second World War and their political background, and the developments to be expected in schools in the near future as a result of our changing society
2 citations
01 Oct 1990
TL;DR: The Tayloristic model of the "thinking" and the "working" subsystems was not dissolved as mentioned in this paper, which stresses specialization and reinforces one-sidedness, leaving little room for wholism and creativity.
Abstract: Soon after its reestablishment in 1945, Yugoslavia saw no other official solution for its management and government modernization but self-management. This was underestimated by many influential people, so the Tayloristic model of the “thinking” and the “working” subsystems was not dissolved. It stresses specialization and reinforces one-sidedness. It also divides people into those who command and those who obey, leaving little room for wholism and creativity. New solutions are needed, and we see them in the transition toward the managerial style “we all think, we all work,” based on creative cooperation of the Many in constant search for change by innovation. This can also be a new partial system of self-management: the doers' innovation of the daily work processes.
TL;DR: In this paper, a new mathematical model of a hydro plant chain was developed which used only two, instead of three, variables, and the optimization algorithm used Newton's method which is applied on the exact L penalty function which allows a nonfeasible starting point so no phase I simplex or projection method is needed at the beginning.
TL;DR: In this paper, the synthesis of (NH4)4UF1O was described, and the powder data of NH44UF10 were indexed on the basis of a monoclinic cell.
TL;DR: Activation of systems specifications as the useful connection between the both customer and developer team is described and gives the dynamic procedural picture of the future system with the optional level of abstraction and with the possibility of tracing the desired event structure.
Abstract: How to present to the customer team the aim and the potential behavior of the future software system after the earliest phases of software development process - the requirements analysis? Activation of systems specifications as the useful connection between the both customer and developer team is described in the paper. Activation gives the dynamic procedural picture of the future system with the optional level of abstraction and with the possibility of tracing the desired event structure. The advantages of the described activating of systems specifications are simplicity, well understandability and the flexible connection with the techniques for generating system specifications. All this improve the customer/developer cycle's communication paths.
29 Nov 1990
TL;DR: In this paper, various system design issues are stressed, from the system and processor architecture, to the language and exception handling, and some design recommendations are given and a timing predictability study of microprocessors is carried out.
Abstract: Timing predictability of the hard real-time systems can only be assured if every feature of them is deterministic. In this paper, various system design issues are stressed, from the system and processor architecture, to the language and exception handling. In the field of architecture, some design recommendations are given and a timing predictability study of microprocessors is carried out. Language features and exception handling are specially emphasised. For certain topics in these fields some solutions to avoid non-determinism are proposed.
TL;DR: In this article, a superconducting microtron unit with incorporated RF generator is described and the operability of this unit is evaluated, and the experience obtained on this miniature vacuum electronics unit could be easily transferred to other bigger and expensive RF accelerators.
TL;DR: The most important task of CASE tools is to unite the methodologies for covering various life cycle phases under one shell.
Abstract: Conventional groups for software development try to increase its efficiency with a more advanced approach to all phases of software life cycle. The need for more formal specifications demands the introduction of computer aided tools which base on the empirically confirmed methodologies. The most important task of CASE tools is to unite the methodologies for covering various life cycle phases under one shell. In the paper the problems, appearing in the contact of the tool with the subjects of the developers team are described.