Sparse decompositions for exploratory pattern analysis

We define and verify the utility of a pattern analysis procedure called sparse decomposition. This technique involves sequentially ``peeling' sparse subsets of patterns from a pattern set, where sparse subsets are sets of patterns which possess a certain degree of regularity or compactness as measured by a compactness measure c. If this is repeated until all patterns are deleted, then the sequence of decomposition ``layers' derived by this procedure provides a wealth of information from which inferences about the original pattern set may be made. A statistic P is derived from this information and is shown to be powerful in detecting clustering tendency for data in reasonably compact sampling windows. The test is applied to both synthetic and real data.     

Parallel Algorithms for Image Template Matching on Hypercube SIMD Computers

This correspondence presents several parallel algorithms for image template matching on an SIMD array processor with a hypercube interconnection network. For an N by N image and an M by M window, the time complexity is reduced from O(N2M2) for the serial algorithm to O(M2/K2 + M * log2 N/K + log2 N * log2 K) for the N2K2-PE system (1 ? K ? M), or to O(N2M2/L2) for the L2-PE system (L ? N). With efficient use of the inter-PE communication network, each PE requires only a small local memory, many unnecessary data transmissions are eliminated, and the time complexity is greatly reduced.     

Tests in an MR reactor of experimental fuel elements of the VVÉR-1000 reactor

Conclusions In an MR reactor performance tests of 16 fuel assemblies, with elements having essentially the same structure as standard VVÉR-100 fuel elements, were carried out. Tests of five more fuel assemblies are continuing. Of the 16 assemblies, 13 were studied in a hot laboratory.The tests in the MR, carried out at high loads and with a large number of transition processes, as well as the postreactor studies, indicated that fuel elements of the specified design (with initial helium pressures of 1.96–2.45 MPa) have a high reliability. None of the elements of the fuel assemblies studied malfunctioned due to design defects or faults in their fabrication. During the tests the jackets were subject to a little oxidation and hydrogenation (zirconium-oxide film<3 m thick, hydrogen content less than 0.008% by mass), and their plasticity remained high (the relative elongation at the working temperature remained at the 20% level).Translated from Atomnaya Énergiya, Vol. 62, No. 5, pp. 312–317, May, 1987.     

New Protective Coatings for Replacing Cadmium Coatings on Steel Parts

Works aimed at solving the problem of replacing toxic cadmium coatings used for protection of aircraft steel parts are reviewed. Numerous electrolytic alloys based on zinc and zinc-bearing coatings of the Colsil and Dacromet types are suggested for the purpose. A VIAM-designed coating based on a Zn – Sn alloy in combination with a modified phosphate coating is considered. It is shown that the protective properties of the combined coating are close to those of a cadmium coating, and the former is recommended for commercial use.     

Predicting phase equilibrium,phase transformation,and microstructure evolution in titanium alloys

Phase transformation and microstructural evolution in commercial titanium alloys are extremely complex. Traditional models that characterize microstructural features by average values without capturing the anisotropy and spatially varying aspects may not be sufficient to quantitatively define the microstructure and hence to allow for establishing a robust microstructure-property relationship. This article discusses recent efforts in integrating thermodynamic modeling and phase-field simulation to develop computational tools for quantitative prediction of phase equilibrium and spatiotemporal evolution of microstructures during thermal processing that account explicitly for precipitate morphology, spatial arrangement, and anisotropy. The rendering of the predictive capabilities of the phase-field models as fast-acting design tools through the development of constitutive equations is also demonstrated. For more information, contact Y.-Z. Wang, Department of Materials Science & Engineering, Ohio State University, 2041 College Road, Columbus, OH 43221, USA; (614) 292-0682; fax (614) 292-1537; e-mail wang.363@osu.edu.     

Water-Acetonitrile Ratio in Perchlorate Cadmium Bath and the Effectiveness of the Addition of Crown-Ester

It is shown that the strongest deceleration of the electrodeposition of cadmium in inhibited media is observed in the domain of loosening the structure of a mixed solvent (0.45 x ₂ 0.25) when the molecular adsorption of organic solvent on Cd is maximum. The process is maximally facilitated in the domain of ordering the acetonitrile's (AN) structure (0.9 x ₂ 0.75), where perchlorate anions dominate at the cathode surface. Crown-ester exhibits maximum inhibition effect under the conditions of preferential adsorption of its molecules, i.e., in the domain of the prevalence of the nonaqueous component in the mixture (x ₂ 0.95).     

Change in structure of an iron-chromium alloy during service

Conclusions As the result of long high-temperature heating the structure of the iron-chromium alloy changes. After service at 1280–1300°C for 500 h light precipitates at the boundaries and in the body of the grain enriched with chromium and molybdenum are observed, which may be considered as the result of separation of the ferrite and as a preparatory stage before precipitation of -phase. In the surface zones of the feeder, nitride and oxide inclusions and products of gas corrosion are observed.Institute of Problems of Casting, Academy of Sciences of the Ukrainian SSR. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 29–30,January, 1985.     

Metallic compounds in the Ti−Cu system

Conclusions In alloys of the Ti–Cu system we found the Ti₃Cu phase at a concentration of 25 at % Cu formed at 1000°C by the peritectic reaction L+Ti₃Cu.Siberian Metallurgical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 10–11, February, 1967.