Reactor dosimetry for VVERs RPV lifetime assessment

A state of the art review of Reactor Dosimetry used for reactor pressure vessel irradiation damage assessment and lifetime evaluation of the Russian type VVER reactors is presented. The necessity of prospective studies in Reactor Dosimetry for improvements that will reduce the neutron fluence uncertainty and in this way to substantiate the extension of NPP lifetime is summarized by specialists in Reactor Dosimetry from countries operating VVER reactors such as Russia, Ukraine, Czech Republic, Finland, Hungary, and Bulgaria, together with specialists from Western European countries such as France, Spain, Germany, Belgium, The Netherlands, and UK, operating PWR and BWR type reactors.     

Selective adsorption of multivalent ions into TiC-derived nanoporous carbon

A TiC-derived carbon (TiC-CDC) was prepared, and the adsorption of large hexacyanocobaltate and tetrabutylammonium ions of approximately same size was examined on this carbon. While selectively absorbing these large ions, it rejects smaller chloride and ammonium ions in mixed electrolyte solutions. The result demonstrates the important role of electrostatic repulsive forces, space-efficient charge packing and hydrophobic ion interactions with the pore walls of TiC-CDC, similar to what is known for a variety of biological membranes.     

Estimation of water balance over catchment areas taking into account the heterogeneity of their landscape conditions

The landscape conditions for forming the water balance and runoff from catchment areas can change considerably under the pressure of natural and anthropogenic factors. The role of hydromorphic transformation of landscapes is important for most of the Ob basin; it results in the paludification of the area. The specific parameter n is used in calculating water balance according to Mezentsev’s method of hydro-climatic calculations to take account of landscape conditions. We suggest determining this parameter’s value by geomorphological features of the landscapes using GIS tools.     

Efficient approximation algorithms for the routing open shop problem

We consider the routing open shop problem being a generalization of two classical discrete optimization problems: the open shop scheduling problem and the metric traveling salesman problem. The jobs are located at nodes of some transportation network, and the machines travel on the network to execute the jobs in the open shop environment. The machines are initially located at the same node (depot) and must return to the depot after completing all the jobs. It is required to find a non-preemptive schedule with the minimum makespan. The problem is NP-hard even on the two-node network with two machines. We present new polynomial-time approximation algorithms with worst-case performance guarantees.     

Densification of transparent yttrium aluminum garnet (YAG) by SPS processing

Nano-size YAG powder co-mixed with 0.25 wt.% LiF was used to fabricate transparent polycrystalline YAG specimens by means of the Spark Plasma Sintering (SPS) technique. The presence of the LiF additive in the initial nano-powder allows obtaining fully dense disc shaped (up to 4 mm thick) transparent specimens at the outcome of a 2 h treatment at 1300 °C. The presence of LiF plays a key role in the mass transport related effects during the densification of YAG to full density and also in the elimination of the residual carbon contamination, allowing reaching a level of optical transmittance close to the theoretical value.     

The virtual production simulation platform: from collaborative distributed simulation to integrated visual analysis

Computational simulations are used for the optimization of production processes in order to significantly reduce the need for costly experimental optimization approaches. Yet individual simulations can rarely describe more than a single production step. A set of simulations has to be coupled to each other to form a contiguous representation of a process chain. Eventually, simulated results have to be analyzed by domain experts to gather insight from the preformed computations. In this paper, we propose an IT infrastructure and software tools that aim at a rather non-intrusive way of coupling resources and domain expert’s knowledge to enable the collaborative setup, execution and analysis of distributed simulation chains. We illustrate the approach in the domain of materials processing. Beyond means originating from the domain of GRID computing for resource management, a data integration component assures semantic data integrity between the simulation steps and stores simulation data in an application independent way. Thus, we can transform this data into native formats for each simulation tool, and finally into a format that allows for contiguous visualizations and an intuitive, comprehensive analysis of complete simulated process chains.     

Size effect on the kinematic parameters of nanometer-thick bilayer films

The behavior of nanodimensional bilayer structures (plates) of finite length consisting of nanometer-thick crystalline Ni and Cu films has been studied by means of molecular dynamics simulation. The inter-atomic interactions were described within the framework of the embedded atom method. It is shown that, in the absence of an external action, the nanostructures perform mechanical oscillations with the amplitude and frequency determined by the length and thickness of the plate. The dependence of the parameters of oscillations of the nanodimensional structures on their dimensions is established. The results can be used in designing components of nanodevices for various applications.     

Pulsed electromagnetic attraction of sheet metals – Fundamentals and perspective applications

The paper is dedicated to the study of pulsed electromagnetic attraction processes which can deform ferromagnetic sheet metal materials such as low carbon steels using low frequency discharges. The analytical model based upon the solution of Maxwell equations explains that magnetic forces are prevailing over the Lorentz forces for low frequency discharges. For electromagnetic forming (EMF) processes employing ferromagnetic sheet metal blanks of low electrical conductivity with relatively slow electric discharges, the magnetic forces should be taken into account in order to achieve a correct representation of electromagnetic forces applied to the blank. An engineering estimate on the size of magneto-static forces and Lorentz-forces is the outcome of the analytical work. In addition to analytical work and validation of the proposed engineering estimate of attracting forces, a single turn coil is introduced which is more robust than previous designs with multiple frequencies and interrupted discharges. The simplified setup only requires a rather slow single frequency low voltage electric discharge which allows for using cheaper and longer life capacitors, substantially reduces the safety implications and also extends the life of the coil insulation.     

On generalized communicating P systems with minimal interaction rules

Generalized communicating P systems are purely communicating tissue-like membrane systems with communication rules which allow the movement of only pairs of objects. In this paper, we study the power of these systems in the case of eight restricted variants of communication rules. We show that seven of these restrictions lead to computational completeness, while using the remaining one the systems are able to compute only finite singletons of non-negative integers. The obtained results complete the investigations of the computational power of generalized communicating P systems and provide further examples for simple architectures with simple functioning rules which are as powerful as Turing machines.     

Techniques for Dispersion of Microorganisms into Air

ABSTRACT

Many commercially available devices initially developed for dispersion of biologically inert particles have been adopted for aerosolization of microoganisms in laboratory settings. However, these dispersion devices are not always adequate for microbial particles, as they do not simulate natural release into air. Wet dispersion methods are appropriate for viruses and most bacteria, whereas dry methods are more suitable for most fungal and actinomycete spores. Characteristics of the resulting aerosol are dependent on the dispersing shear forces and the sensitivity and agglomeration of the tested microorganisms. Consequently, each microbial group may need a specific dispersion technique. The following devices have been developed and tested in this study: the bubbling aerosol disperser, the agar-tube disperser, and the swirling-flow disperser. Testing included the evaluation of both physical and microbiological characteristics of aerosolized microorganisms. Each of the dispersers has shown several advantages over commercially available ones. When used for the dispersion of bacteria from the liquid suspension, the bubbling aerosol disperser was found to produce considerably fewer amounts of microbial fragments and much lower levels of microbial metabolic injury than the commercially available Collison nebulizer. Fungal spores dispersed from their colonies by the agar-tube disperser were found to have a more stable aerosol concentration and a lower fraction of agglomerates than achievable by conventional powder dispersion. The swirling-flow dispersion technique was used for aerosolization of actinomycetes because the agar-tube disperser could not provide a stable concentration of these spores due to their smaller size. The tests have shown that new methods minimize the changes of properties of the microorganisms during their aerosolization in the laboratory.