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.     

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.     

Optimization of Physiological Growth Conditions for Maximal Gamma-linolenic Acid Production by Cunninghamella blakesleeana-JSK2

Effects of various cultural conditions on biomass, lipid and Gamma-linolenic acid (GLA) production were investigated in the oleaginous fungus Cunninghamella blakesleeana-JSK2 isolated from soil. The GLA production was influenced by various factors such as growth condition (static and shaken), incubation time, pH, temperature, carbon and nitrogen sources. The results indicated that optimum GLA production (21 %) was obtained when the fungus was grown under shaken condition at 120 rpm for 6 days with optimum pH and temperature of 6 and 28 °C ,respectively. Glucose and potassium nitrate enhanced the GLA production. Urea and sucrose were poor substances for biomass, lipid and GLA production.     

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.     

Hydrogen from empty cotton boll agro-waste via thermochemical route and feasibility study of operating an IC engine in continuous mode

Hydrogen can be cited as prospective source of clean power. In this work hydrogen rich syn-gas generated from the agro-waste, empty cotton bolls was injected into an IC engine in continuous mode along with gasoline. At the air-fuel ratio of 23.40, specific fuel consumption of 0.35 kg kWh^?1, the engine could be operated with higher efficiency than with gasoline alone. A distinct reduction in emission characteristics could also be seen. Empty cotton bolls derived after removal of cotton from the flower in field, was first studied for fuel properties. The reasonably high heating value (HHV) of 17.54 MJ kg^?1 suggested that it could be a precursor to hydrogen via two stepped thermo-chemical process. The first step involved slow pyrolysis of the biomass at 500 °C for 60 min at a heating rate of 10 °C min^?1 yielding 39.71% bio-char by weight. The C, H, N, S and O contents of the produced bio-char was 59.91, 2.91, 0.72, 0.47 and 35.99% respectively and its HHV was 26.7 MJ kg^?1. Steam gasification of this bio-char, at 700 °C and water flowrate of 7 mL min^?1 exhibited maximum hydrogen yield of 67.42% (v/v) in the syn-gas mixture. Subsequent enrichment of the gas using ethanolamine/ethylene diamine and KMnO₄ solutions resulted in more than 90% (v/v) hydrogen in the combustible gas mixture and the test engine could be effectively operated.     

Influence of salt concentration on solubility and tie-line data for the system: Formic acid + n-butanol + water

The tie-line and solubility data, i.e. formic acid (FA) + n-butanol + water + NaCl, were resolved at T = 298.15 K and under ambient pressure. The Othmer–Tobias equation was applied in this study. The experimental data were correlated and all linear correlation coefficients were found to be approximately equal to 1. Both the Universal Quasi-chemical Theory (UNIQUAC) and Nonrandom Two Liquid Theory (NRTL) and NRTL models were employed in order to compare the experimental liquid–liquid equilibrium (LLE) and tie-line data. Consequently, the calculated and experimental data proved to be a good fit. Results show that adding salt to the system proved beneficial by increasing the separation of FA from water.     

Numerical modelling of calcination reaction mechanism for cement production

Calcination is a thermo-chemical process, widely used in the cement industry, where limestone is converted by thermal decomposition into lime CaO and carbon dioxide CO₂. The focus of this paper is on the implementation and validation of the endothermic calcination reaction mechanism of limestone in a commercial finite volume based CFD code. This code is used to simulate the turbulent flow field, the temperature field, concentrations of the reactants and products, as well as the interaction of particles with the gas phase, by solving the mathematical equations, which govern these processes. For calcination, the effects of temperature, decomposition pressure, diffusion and pore efficiency were taken into account. A simple three-dimensional geometry of a pipe reactor was used for numerical simulations. To verify the accuracy of the modelling approach, the numerical predictions were compared with experimental data, yielding satisfying results and proper trends of physical parameters influencing the process.     

Investigations of ductile damage during the process chains of toothed functional components manufactured by sheet-bulk metal forming

Sheet-bulk metal forming processes combine conventional sheet forming processes with bulk forming of sheet semi-finished parts. In these processes the sheets undergo complex forming histories. Due to in- and out-of-plane material flow and large accumulated plastic strains, the conventional failure prediction methods for sheet metal forming such as forming limit curve fall short. As a remedy, damage models can be applied to model damage evolution during those processes. In this study, damage evolution during the production of two different toothed components from DC04 steel is investigated. In both setups, a deep drawn cup is upset to form a circumferential gearing. However, the two final products have different dimensions and forming histories. Due to combined deep drawing and upsetting processes, the material flow on the cup walls is three-dimensional and non-proportional. In this study, the numerical and experimental investigations for those parts are presented and compared. Damage evolution in the process chains is simulated with a Lemaitre damage criterion. Microstructural analysis by scanning electron microscopy is performed in the regions with high mechanical loading. It is observed that the evolution of voids in terms of void volume fraction is strongly dependent on the deformation path. The comparison of simulation results with microstructural data shows that the void volume fraction decreases in the upsetting stage after an initial increase in the drawing stage. Moreover, the concurrent numerical and microstructural analysis provides evidence that the void volume fraction decreases during compression in sheet-bulk metal forming.