Concerted utility review of VVER-440 safety research needs (VERSAFE)

There are twelve operating VVER-440/213 reactors in the Czech Republic, Hungary and Slovakia. The plant owners have carried out extensive safety enhancement programmes, which have included measures to improve prevention, mitigation and control of design basis accidents. Recently, there have been a number of projects to study the Severe Accident Management aspects of these plants. The plant owners have also initiated Plant Life Management programmes. The objective of the VERSAFE Concerted Action is to create a network of the VVER-440/213 plant owners and operators, which aims at definition of the further research needs of severe accidents and plant ageing from the utilities’ viewpoint. The starting point is to formulate a general approach to severe accident management and plant life management and then proceed to define the needs for the additional information expected from the safety research. The role of national research institutes and organisations of the partner countries is of crucial importance in performing such research and, thus, creating and maintaining the expertise on the national level. The successful completion of the project will assist in establishing well-defined research projects that are oriented to the needs of the end-users and provide information that can be used to facilitate and support the negotiations of the EU applicant countries operating VVER-440 reactors.     

Overexpression of TcNTPDase-1 Gene Increases Infectivity in Mice Infected with Trypanosoma cruzi

Ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are enzymes located on the surface of the T. cruzi plasma membrane, which hydrolyze a wide range of tri-/-diphosphate nucleosides. In this work, we used previously developed genetically modified strains of Trypanosoma cruzi (T. cruzi), hemi-knockout (KO +/−) and overexpressing (OE) the TcNTPDase-1 gene to evaluate the parasite infectivity profile in a mouse model of acute infection (n = 6 mice per group). Our results showed significantly higher parasitemia and mortality, and lower weight in animals infected with parasites OE TcNTPDase-1, as compared to the infection with the wild type (WT) parasites. On the other hand, animals infected with (KO +/−) parasites showed no mortality during the 30-day trial and mouse weight was more similar to the non-infected (NI) animals. In addition, they had low parasitemia (45.7 times lower) when compared with parasites overexpressing TcNTPDase-1 from the hemi-knockout (OE KO +/−) group. The hearts of animals infected with the OE KO +/− and OE parasites showed significantly larger regions of cardiac inflammation than those infected with the WT parasites (p < 0.001). Only animals infected with KO +/− did not show individual electrocardiographic changes during the period of experimentation. Together, our results expand the knowledge on the role of NTPDases in T. cruzi infectivity, reenforcing the potential of this enzyme as a chemotherapy target to treat Chagas disease (CD).     

An upgraded artificial bee colony (ABC) algorithm for constrained optimization problems

Artificial bee colony (ABC) algorithm developed by Karaboga is a nature inspired metaheuristic based on honey bee foraging behavior. It was successfully applied to continuous unconstrained optimization problems and later it was extended to constrained design problems as well. This paper introduces an upgraded artificial bee colony (UABC) algorithm for constrained optimization problems. Our UABC algorithm enhances fine-tuning characteristics of the modification rate parameter and employs modified scout bee phase of the ABC algorithm. This upgraded algorithm has been implemented and tested on standard engineering benchmark problems and the performance was compared to the performance of the latest Akay and Karaboga’s ABC algorithm. Our numerical results show that the proposed UABC algorithm produces better or equal best and average solutions in less evaluations in all cases.     

Microalgae biomass interaction in biopolymer gelled systems

Microalgae are an enormous biological resource, representing one of the most promising sources for the development of new food products and applications. Pea protein/κ-carrageenan/starch gels, interesting vegetarian alternatives to dairy desserts, served as model systems to study the addition of microalgal biomass, its effect, and subsequent rheological behaviour. Spirulina and Haematococcus gels presented a markedly different rheological behaviour compared to the control mixed biopolymer gelled system. The present goal is to clarify how these microalgae affect the gelation and interact with each biopolymer present in the complex mixed gel system. Hence, the aim of the present work is to study the effect of Spirulina and Haematococcus microalgal biomass addition on the rheological behaviour of pea protein, κ-carrageenan and starch simple gels, as well as in pea protein/κ-carrageenan and pea protein/starch systems. The gelation process was monitored in-situ through dynamic oscillatory measurements (temperature, time and frequency sweep tests) for a 24 h maturation period, and rheological results were supported with fluorescence optical microscopy observations. The addition of Spirulina and Haematococcus to biopolymer gelled systems induced significant changes in the gels’ rheological behaviour and microstructure. In general, it was observed that the gelling mechanism is ruled by the biopolymers, while microalgae seem to be embedded in the gel network acting as active particle fillers. The addition of Haematococcus resulted in more structured gels in comparison to the control and Spirulina systems. In the case of κ-carrageenan gels, both microalgae induced a large increase in the rheological parameters, which should be related to the high ionic content of microalgal biomass. Spirulina addition on starch systems promoted a decrease in the gels’ rheological parameters. This should be related to the starch gelatinization process, probably by competing for water binding zones during the granules’ hydration process.     

Seasonal variations in total fatty acid composition of muscles and eye sockets of tucunaré (Cichla sp.) from the Brazilian Amazon area

Seasonal variations in total fatty acid compositions of tucunaré, Cichla sp. in the Janauacá Lake of the Amazon basin were determined by GC. Saturated fatty acids (SFAs) were found to be at higher concentrations than monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) in two seasonal periods. Major fatty acids were palmitic (16:0, 48.5–51.6% of total SFA), oleic (18:1ω9, 43.9–50.2% of total MUFA), docosahexaenoic (DHA, 22:6ω3, 13.5–27.9% of total PUFA) and arachidonic acid (AA, 20:4ω6, 16.0–19.6% of total PUFA). Polyunsaturated fatty acids were the most abundant in muscle during the flood period, and more especially fatty acids 22:6ω3 (10%) and 20:4ω6 (7%). There were no significant variations amongst total lipid SFA, MUFA, and PUFA from eye sockets. The ω6 fatty acid percentages were always higher than the ω3 fatty acid percentages in tucunaré, with ω6/ω3 ratios varying between 1.02 and 1.6 in the flood and drought periods.     

基于MPPMSG的混合高压直流风电系统故障穿越技术

为解决传统风电系统变换级数多的问题,文中提出了一种基于多相永磁同步电机(MPPMSG)的混合高压直流风电系统拓扑。电机多套绕组分别连接单极性变流器并在直流侧串联形成高压直接接入直流母线,一套绕组向电机注入无功功率以改善电机调速和稳态性能。岸上变电站采用电网换相换流器,直流母线短路时可阻断短路电流。为解决多绕组耦合问题,MPPMSG采用了反馈解耦的控制策略。根据发电机短路特性分析,提出了直流母线短路时限制电机短路电流以及直流故障穿越的控制策略。最后,利用PSCAD/EMTDC搭建风电系统开关电路仿真模型,验证了所提控制策略的有效性。     

Effect of RF magnetron sputtering parameters on the optimization of the discharge capacity of ternary lithium oxide thin films

Journal of Materials Science: Materials in Electronics - The increasing demand for lithium-ion batteries has stimulated the investigation of new compounds in order to reduce the costs and the...     

Stereometric analysis of nanostructured boehmite coatings synthesized by aluminum nitride powder hydrolysis

We studied the morphological properties of precipitated, nanostructured, boehmite coatings on a polished alumina surface by exploiting the aluminum nitride (AlN) powder hydrolysis at elevated temperatures. The hydrolysis tests of the 3 wt% AlN powder suspensions in the temperature range 50–90 °C were performed in order to estimate the time needed for the synthesis of the coatings. They consisted of interlocked boehmite lamellas, positioned perpendicularly to the ceramic surface, and they exhibited a strong temperature-dependent size and surface density. The aim of this research was a quantitative assessment of the as-formed boehmite coatings. Based on electron microscopy micrographs, a stereometric analysis of the as-prepared coatings was performed in order to estimate the relevant geometric parameters of the lamellas. In spite of the temperature-dependent lamellas’ size and surface density, the specific volume of the coatings was similar for all the synthesis temperatures.     

Influence of dietary vitamin C and selenium,alone and in combination,on the composition and oxidative stability of meat of broilers

Information on the combined effect of dietary vitamin C and Se on the composition and oxidative stability of meat of broilers is not available in the literature. In the present experiment, male broiler chickens were fed a maize–wheat–soya diet supplemented with vitamin C at 280 and 560 mg/kg of diet, and Se (sodium selenite or selenised yeast; Se) at 0.3 mg/kg for 5 weeks. After slaughter, samples of thigh meat were analysed. The supplementation of diets with vitamin C or Se increased the protein concentration of the meat at the expense of fat. Vitamin C supplementation increased the vitamin C content of the meat in a dose-dependent manner and decreased the vitamin A concentration in the meat of broilers fed diets with sodium selenite or without a Se supplement. In the meat of the broilers that were fed these diets, the vitamin C decreased the lipid oxidation in meat that was stored for 5 days. No sparing effect of vitamin C was apparent on the amount of vitamin E in the meat. Selenised yeast was more effective in the enrichment of meat with Se than was selenite. Both Se sources increased the activity of glutathione peroxidase and the oxidative stability of the meat.