Rehabilitation of the radioactively contaminated objects and territory of the Russian Science Center Kurchatov Institute

This article is devoted to work done in 2002–2006 as part of the unified project Reabilitatsiya to rehabilitate radiation hazardous objects and sections of the radioactively contaminated territory of the Russian Science Center Kurchatov Institute. The main objects of the rehabilitation work were old storage sites built for radioactive wastes on the territory of the Institute when military and civilian nuclear technologies were under development. The structural features of the storage sites, including the volumes and characteristics of the wastes stored, are presented. The salient aspects of the disposal sites, taken into account during the rehabilitation work, are discussed. The organization of the rehabilitation operations and the sequence in which they are performed, the special features of the technical design solutions used, the technological methods, and ways for conducting the work are described. __________ Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 300–306, May, 2007.     

Accuracy estimate and optimization techniques for SimRank computation

The measure of similarity between objects is a very useful tool in many areas of computer science, including information retrieval. SimRank is a simple and intuitive measure of this kind, based on a graph-theoretic model. SimRank is typically computed iteratively, in the spirit of PageRank. However, existing work on SimRank lacks accuracy estimation of iterative computation and has discouraging time complexity. In this paper, we present a technique to estimate the accuracy of computing SimRank iteratively. This technique provides a way to find out the number of iterations required to achieve a desired accuracy when computing SimRank. We also present optimization techniques that improve the computational complexity of the iterative algorithm from O(n ⁴) in the worst case to min(O(nl), O(n ³/ log₂ n)), with n denoting the number of objects, and l denoting the number object-to-object relationships. We also introduce a threshold sieving heuristic and its accuracy estimation that further improves the efficiency of the method. As a practical illustration of our techniques, we computed SimRank scores on a subset of English Wikipedia corpus, consisting of the complete set of articles and category links.     

International Conference on Plasma Physics and Controlled Thermonuclear Reactions

The International Conference on Plasma Physics and Controlled Thermonuclear Reactions, organized by the IAEA, was held in Salzburg, Austria September 4–9, 1961. The conference was attended by 508 delegates from 29 countries and 6 international organizations. One hundred and eleven reports of the two hundred and fifty presented at the conference were read at the sessions; in addition there were review talks by Artsimovich (USSR) and Rosenbluth (USA). All the reports read at the conferences and the pertinent discussion will be published in Nuclear Fusion. The present paper is a brief review of the results reported at the conference.     

UV absorption in solutions and crystals of potassium dihydrogen phosphate

The effects of impurities and growth conditions on the optical quality of potassium dihydrogen phosphate (KDP) crystals were examined. The transmittance of crystals grown under various conditions was measured in the range 200–400 nm for a larger number of impurities than previously. The highest transmittance is afforded by crystals grown from solutions with the stoichiometric composition at 55‡C and a growth rate of 1 mm per day.     

Experimental and numerical investigation of the electrophysical properties of products of combustion of hydrogen in oxygen seeded with alkali metals

Results are given of experimental and numerical investigations of electrical conductivity and mobility of electrons in the products of combustion of hydrogen-oxygen fuel seeded with cesium or potassium-sodium eutectic. The experiments were performed in model (flow rate of 0.9 kg/s, thermal power N _th ≈7 MW) and large-scale experimental (flow rate ≈12 kg/s, N _th ≈ 150 MW) facilities with the pressure in the combustor ranging from 2 to 6 MPa, oxidizer excess coefficients of 0.6 to 1.1, mass fractions of the seed in the fuel of 0.3 to 0.9 with the Mach number M ≈ 2.4. The basic characteristics, structural schemes, and general views of the facilities are given. When cesium is used for seeding, the experimentally obtained values of electrical conductivity may be as high as σ_el ≈ 20 S/m, those of σ_elν² ≈ 115 S/m (km/s)², and of electron mobility ? 0.11 T^?1 at a pressure of ≈0.3 MPa, temperature of ≈2800 K, and flow velocity ν ≈ 2500 m/s. Under the same conditions for combustion products seeded with KNa eutectic, we have σ^el ≈ 9 S/m, σ_elν² ≈ 65 (S/m)(km/s)², and electron mobility of 0.09 T^?1.     

“Rosshelf” company and development of the arctic shelf of Russia

Power Technology and Engineering -