Curvature Correction in the Strutinsky's Method

Mass calculations carried out by Strutinsky's shell correction method are based on the notion of smooth single particle level density. The smoothing procedure is always performed using curvature correction. In the presence of curvature correction a smooth function remains unchanged if smoothing is applied. Two new curvature correction methods are introduced. The performance of the standard and new methods are investigated using harmonic oscillator and realistic potentials.Comment: 4 figures, submitted to Journal of Physics G: Nuclear and Particle Physic

Magnetic properties of Sn/1-x/Cr/x/Te diluted magnetic semiconductors

We present the studies of Sn/1-x/Cr/x/Te semimagnetic semiconductors with chemical composition x ranging from 0.004 to 0.012. The structural characterization indicates that even at low average Cr-content x < ?0.012, the aggregation into micrometer size clusters appears in our samples. The magnetic properties are affected by the presence of clusters. In all our samples we observe the transition into the ordered state at temperatures between 130 and 140 K. The analysis of both static and dynamic magnetic susceptibility data indicates that the spin-glass-like state is observed in our samples. The addition of Cr to the alloy seems to shift the spin-glass-like transition from 130 K for x = 0.004 to 140 K for x = 0.012.Comment: 4 pages, 4 figure

Alternative Routes from Fossil Resources to Chemical Feedstocks

The chemical industry depends very heavily on hydrocarbon feedstocks, which are presently derived almost exclusively from crude oil. Although only about seven percent of the hydrocarbons suitable for chemical processing are actually used in this way, it is already clear that there is a potential conflict between the needs of the energy sector and those of the chemical industry: they are competing for increasingly scarce liquid hydrocarbon resources. The authors suggest that the supply of hydrocarbon feedstocks to the chemical industry could be protected against the effects of changing patterns of energy use by modifying the underlying industrial structure. They have developed an approach which takes a variety of production processes (either in use or under development), compares their efficiency their consumption of different resources, etc., and finds the combination of technologies that best satisfies a particular demand while staying within the limits imposed by resource availability. This approach uses the techniques of interactive decision analysis to incorporate the unquantifiable social and political factors that must influence any development decision. By way of illustration, the method is applied to one very small part of the problem area: the different routes to the production of methanol. This report does not attempt to provide any final answer to the problem of feedstock supply, but rather to explain one possible approach to the problem and discuss some intermediate results. It is addressed not only to researchers, but also, and in particular, to all decision makers and industrial consultants facing problems of this type

Generating Efficient Alternatives for Development in the Chemical Industry

Industrial development can be seen as the process of changing the production structure by means of investment over the course of time. To control this development to the benefit of society while maintaining the profitability of the industry, decision makers must learn how socioeconomic changes and market conditions affect the static and dynamic properties of the production structure. This paper reports on the progress of collaborative research into the design of tools which could help decision makers to control development in the chemical industry. The basic approach is to formulate a model of the equilibrium state of the industry or, in the case considered here, of a particular subsector of the industry. The development process is initially described by a static multiobjective optimization problem, from which a dynamic multiobjective optimization problem is then derived. An example illustrating the use of this method for the pesticide-producing sector is given. The optimization problem and method for controlling industrial development put forward in this paper were worked out as part of the research program on Growth Strategy Optimization Systems (GSOS), sponsored by the Ministry of the Chemical Industry in Poland. This program is actually carried out at the Institute for Control and Systems Engineering (ICSE), part of the Academy of Mining and Metallurgy (AMM) in Cracow. The multiobjective optimization method for generating efficient alternatives and the related software were developed by the System and Decision Sciences Area at IIASA. This collaborative research was carried out within the framework of the agreement on scientific cooperation cosigned by IIASA and the AMM in June 1980

Fission barriers in covariant density functional theory: extrapolation to superheavy nuclei

Systematic calculations of fission barriers allowing for triaxial deformation are performed for even-even superheavy nuclei with charge number $Z=112-120$ using three classes of covariant density functional models. The softness of nuclei in the triaxial plane leads to an emergence of several competing fission pathes in the region of the inner fission barrier in some of these nuclei. The outer fission barriers are considerably affected by triaxiality and octupole deformation. General trends of the evolution of the inner and the outer fission barrier heights are discussed as a function of the particle numbers.Comment: 24 pages, 8 tables, 12 figure