A decision problem under uncertainty for nuclear power system development

Decision making under uncertainty is a further step in comparison with decision under risk in the more realistic approach to decision problems concerning, for instance, nuclear power system development. In this paper the theory developed is, however, based in a great measure on that of risk preference. The theory of decision making under uncertainty is applied to a nuclear power system NPS consisting of PHWRs and PWRs integrated with LMFBRs. Nine development alternatives of the system which evolves for a period of 40 years are considered. The fast reactor integration is accomplished beginning in year 15 with a variable time delay so that for every alternative, six final states are possible. An econometric model of the system offers the cost price of annual energy generated by the system at the end of the given time interval for every possible state of any alternative. Further, the complete ignorance case is considered, resulting from the principle of insufficient reason, and the risk preference theory is applied. Then the partial ignorance case is taken into account and finally it it shown how we can infer a plausible a priori optimal probability distribution to have an optimal decision characterized by an optimal selected development alternative, for which a minimum certain equivalent of cost price of annual energy is realized with an accepted level of risk and a determined value of risk averter.     

Multilayer biopolymer/poly(ε-caprolactone)/polycation nanoparticles

Combining two or more materials for carrier construction is one of the topical approaches to avoid/diminish deficiencies and to increase functionality in delivery systems for bioactive compounds. In this context, here, multilayered nanoparticles comprising both natural (atelocollagen—AteCol; hyaluronic acid derivative—HA) and synthetic [poly(ε-caprolactone)—PCL; polyethylenimine—PEI; poly(l-lysine)—PLL] polymers were prepared and characterized. The combination of a modified double-emulsion method with polymer modification reactions allowed improvement of the polymer particle’s functionality. Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, fluorescence spectroscopy, dynamic light scattering, transmission/scanning electron microscopy and fluorescence microscopy investigations confirmed the obtention of the envisaged nanomaterials with the expected composition and structure. The double-layered biopolymer/PCL-based nanoparticles formed in a first synthesis step could be successfully coated with PEI and PLL. The gel electrophoresis assay attested the DNA packing ability of the formed nano-vehicles involving surface grafting of the former biopolymer/PCL-based nanoparticles in the case of both cationic polymers, for N/P ratios of 10 (PEI coating) and 3.5 (PLL coating), respectively. According to the FTIR registration, the protein’s native form was preserved. Considering the advantage of biocompatibility and high versatility (controlled size, tuned chemistry and biodegradation rate) some of the resulted nanomaterials may appear as potential candidates for biomedical uses (i.e., drug/gene delivery and tissue engineering).     

Features of the mechanical properties of phosphate glasses doped with rare earth elements under indentation

The microstructure, as well as the mechanical and thermal properties, of phosphate glasses (PhGs) doped with rare earth elements (REEs), namely, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, and Yb, were studied in the present paper. The strength parameters of the PhGs and their dependence on the load value modification were estimated by the dynamic indentation method. Three specific stages were revealed in the deformation process, including nano-, submicro-, and microdeformation. The factors responsible for each stage were determined. It was shown that the strength properties (Young’s modulus and hardness) and the thermal characteristics (the lower and upper annealing temperature, the softening temperature, and the vitrification temperature) exhibit no evident relationship with the atomic mass and ionic radius of an REE. An assumption was made that the elastic and plastic properties of PhGs can be determined by the internal structure of the glasses.     

Highly photoemissive polymer–transition metal complexes based on poly(2‐hydroxyethyl) methacrylate

The paper presents several new polymer complexes based on poly(2‐hydroxyethyl) methacrylate (P‐HEMA) and transition metals including Y³⁺, Eu³⁺, Tb³⁺ and Dy³⁺. Red‐, green‐, blue‐ and yellow‐emitting polymer complexes with remarkable photoluminescent (PL) properties, high degree of transparency and excellent processability both in bulk and in thin film were prepared and investigated. In the case of the prepared P‐HEMA–Eu³⁺ and P‐HEMA–Tb³⁺ polymer complexes, divinylbenzene was used as a crosslinker resulting a markedly enhanced PL emission, most probably due to the presence of the benzene rings which improve the efficiency of the energy transfer to the cation emissive centres. The prepared polymer complexes were structurally investigated through Fourier transform infrared and X‐ray photoelectron spectroscopies while atomic force microscopy was used to study the morphology of the prepared thin films. Steady‐state fluorescence spectroscopy and absolute PL quantum yield were used for the investigation of the luminescent properties. The impressive PL emission and the convenience of preparation in bulk or thin films could be important arguments for a wide area of applications ranging from photonic conversion materials in optoelectronic devices (light‐emitting diodes, flat‐panel displays) to full‐colour watermarks on special‐purpose papers or PL inks and coatings. © 2019 Society of Chemical Industry     

Stochastic approach in the optimization of A nuclear power system

The paper deals with a CANDU-CANDU (Th/Pu)-LMFBR (PuO₂) nuclear power system which evolves in a finite time interval. Its initial evolution is only in the CANDU variant, and subsequently in the variants CANDU (Th/Pu) and LMFBR (PuO₂) by the use of Pu produced in the system. It is assumed that the fuel burn-up in the LMFBR (PuO₂) reactors is a random value, as it is governed by an a priori determined field of probability. The resources of natural uranium and Pu which severely influence the development of the system are also random, as they cannot be definitely known, and moreover they are actually governed by another field of probability already known. Under these conditions, the set of optimal solutions and associated optimal values represented by the nuclear electric powers released in the system at the end of the considered time interval have to be derived. Concomitantly, the distribution of the optimal value, its average value and standard deviation can be evaluated. This type of stochastic approach to nuclear power system optimization is much more valid than the deterministic approach, as it supplies information of interest for the decision-makers engaged in the solution of a nuclear power policy.     

Periodic autoregressive model identification using genetic algorithms

Periodic autoregressive (PAR) models extend the classical autoregressive models by allowing the parameters to vary with seasons. Selecting PAR time‐series models can be computationally expensive, and the results are not always satisfactory. In this article, we propose a new automatic procedure to the model selection problem by using the genetic algorithm. The Bayesian information criterion is used as a tool to identify the order of the PAR model. The success of the proposed procedure is illustrated in a small simulation study, and an application with monthly data is presented.     

Synthesis and Biocompatibility of Maleic Anhydride Copolymers: 1. Maleic Anhydride–Vinyl Acetate,Maleic Anhydride–Methyl Methacrylate and Maleic Anhydride–Styrene

A series of maleic anhydride (MA)–vinyl acetate (VA), MA–methyl methacrylate (MM) and MA–styrene (S) copolymers were prepared and characterized. By employing various amounts of initiator, MA–VA, MA–MM and MA–S copolymers with molecular weights ranging between 18 000 and 219 000 were obtained. The ‘in vivo’ and ‘in vitro’ tests performed on K562 cellular cultures (human chronic myeloid leukaemia) and also on Westar rats (inoculated with the Walker 256 carcinosarcome) showed that, as a function of the molecular weight, the copolymers synthesized had a 50% in vitro cytotoxicity and a mean tumour regression of a maximum of 68%. © 1997 SCI.