Photoluminescent properties of Al₂O₃ films containing gold nanoparticles, which are prepared by pulse laser deposition

Photoluminescent porous films of aluminum oxide containing gold nanoparticles were prepared using pulse laser deposition from backward flow of particles from erosion torch. Measurements of time-resolved photoluminescence spectra revealed high intense photoluminescent band with the peak close to 2.4 eV and its low-energy shoulder at 1.6 - 1.7 eV, high-energy shoulder at 2.9 eV, with relaxation times up to several microseconds. Studied were the influence of formation conditions and gold concentrations in the target on photoluminescent properties of films. The nature of photoluminescence related with radiative recombination of electrons and holes in Au nanoparticles as well as local centers in Al₂O₃ matrix is discussed

Possibility of Various Types SNF Reprocessing at the PA Mayak exampled with AMB SNF

AbstractFor the purpose of reprocessing of irradiated nuclear fuel from the water-cooled graphite-moderated pressure-tube reactor named AMB from decomissioned Russian “Atom Peaceful Big”, modernization of the process flow-sheet of the RT-1 plant is being carried out at PA Mayak with participation of FSUE KRI and VNIINM. A particular AMB SNF feature is extremely broad range of fuel compounds with the main ones being the uranium-molybdenum metal, uranium oxide and uranium carbide compositions usually dispersed in magnesium or calcium. Wide range of fuel compositions required to amend SNF dissolution, extraction processing, evaporation of high-level radioactive wastes and vitrification of high-level radioactive wastes. The above set of laboratory research was completed with dynamic tests using samples of AMB from the water-cooled graphite-moderated pressure-tube reactor. Tests have shown the possibility of processing the entire range of AMB SNF at the radiochemical plant RT-1 plant of the PA Mayak. Thus, the ability of the RT-1 plant to process different fuel compositions, including the long-term research reactor fuel have been proved experimentally

Domain Decomposition Approach for Automatic Parallel Generation of 3D Unstructured Grids

The desire to simulate more and more geometrical and physical features of technical structures and the availability of parallel computers and parallel numerical solvers which can exploit the power of these machines have lead to a steady increase in the number of grid elements used. Memory requirements and computational time are too large for usual serial PCs. An a priori partitioning algorithm for the parallel generation of 3D nonoverlapping compatible unstructured meshes based on a CAD surface description is presented in this paper. Emphasis is given to practical issues and implementation rather than to theoretical complexity. To achieve robustness of the algorithm with respect to the geometrical shape of the structure authors propose to have several or many but relatively simple algorithmic steps. The geometrical domain decomposition approach has been applied. It allows us to use classic 2D and 3D high-quality Delaunay mesh generators for independent and simultaneous volume meshing. Different aspects of load balancing methods are also explored in the paper. The MPI library and SPMD model are used for parallel grid generator implementation. Several 3D examples are shown