Reliability versus performance for critical applications

Applications implemented on critical systems are subject to both safety critical and real-time constraints. Classically, applications are specified as precedence task graphs that must be scheduled onto a given target multiprocessor heterogeneous architecture. We propose a new method for simultaneously optimizing two objectives: the execution time and the reliability of the schedule. The problem is decomposed into two successive steps: a spatial allocation during which the reliability is maximized (randomized algorithm), and a scheduling during which the makespan is minimized (list scheduling algorithm). It allows us to produce several trade-off solutions, among which the user can choose the solution that best fits the application’s requirements. Reliability is increased by replicating adequate tasks onto well chosen processors. Our fault model assumes that processors are fail-silent, that they are subject to transient failures, and that the occurrences of failures follow a constant parameter Poisson law. We assess and validate our method by running extensive simulations on both random graphs and actual application graphs. They show that it is competitive, in terms of makespan, compared to existing reference scheduling methods for heterogeneous processors (HEFT), while providing a better reliability.     

The use of natural Kazakhstan zeolites for the development of gas purification catalysts

The results of investigation of catalysts based on natural zeolite in comparison with synthetic ZSM-5 zeolite used in reduction of nitrogen oxides and conversion of carbon monoxide are presented. It was found that rearrangement of the crystal structure of natural zeolite begins upon heating it above 500 °C in air. The structure of natural zeolite has been improved by introduction of various modifiers and selection of thermal regime of samples training. It has been shown that developed compositions of press-mass for preparation of carriers for gas purification catalysts in the form of granules and tablets satisfy the requirements on ductility and mechanical strength. The efficiency of synthesized granular and block Cu–Ce, Cu–Ni–Cr, Ti–V, Ti–VW, and TiO₂–V₂O₅ catalysts based on natural and synthetic zeolites was determined in conversion of CO and nitrogen oxides. The results of X-ray structure analysis of clinoptilolite of the Republic of Kazakhstan deposits—Chankanai and Taizhuzgen—are represented in comparison with synthetic ZSM-5 zeolite. The paper also comprises data about their thermal stability, ductility, and strength of compositions on their base. Metals particles morphology and dispersity are studied by the method of electronic microscopy. These particles were used as active components of synthesized catalysts.     

Recovery of rare earth metals (REMs) from primary raw material: sulphatization-leaching-precipitation-extraction

The present study is devoted to the extraction of rare-earth metals (REMs) from a high-silica ore found in one of the deposits in Kazakhstan. The ore was processed in a mixture with sulfuric acid at 200°C (sulphatization) and subsequently followed by water leaching of the sulphate product (sinter), REMs were extracted into the solution. Precipitation of the REMs-containing hydrate product from the sulfate solution was carried out with sodium hydroxide. In order to obtain the REMs-containing nitrate solution, the precipitate was dissolved in nitric acid. REMs solvent extraction from nitrate solutions was carried out with tributyl phosphate (TBP).     

Load-balancing spatially located computations using rectangular partitions

Distributing spatially located heterogeneous workloads is an important problem in parallel scientific computing. We investigate the problem of partitioning such workloads (represented as a matrix of non-negative integers) into rectangles, such that the load of the most loaded rectangle (processor) is minimized. Since finding the optimal arbitrary rectangle-based partition is an NP-hard problem, we investigate particular classes of solutions: rectilinear, jagged and hierarchical. We present a new class of solutions called m-way jagged partitions, propose new optimal algorithms for m-way jagged partitions and hierarchical partitions, propose new heuristic algorithms, and provide worst case performance analyses for some existing and new heuristics. Moreover, the algorithms are tested in simulation on a wide set of instances. Results show that two of the algorithms we introduce lead to a much better load balance than the state-of-the-art algorithms. We also show how to design a two-phase algorithm that reaches different time/quality tradeoffs.     

Desorption of rhenium from weakly basic anion exchangers

The desorption of rhenium from an A172 anion exchanger with an ammonia solution has been studied. A172 and A170 anion exchangers have been investigated with infrared spectroscopy. The difference in their structures has been revealed so that A172 can be assigned to a medium basic anion exchanger type. The reason for the low desorption of rhenium from the A172 anion exchanger has been determined.     

Transcriptional regulation of vascular endothelial growth factor gene expression in ovarian bovine granulosa cells

From rape (Brassica napus) seedlings proteins able to bind fatty acids and their CoA-esters were purified by gel filtration and cation-exchange chromatography. Among the four proteins detected, one of them (peak IV) appeared purified to homogeneity. This protein is a monomer with a molecular mass of about 9 kDa, as estimated by gel filtration and by polyacrylamide gel electrophoresis. The isoelectric point of the rape protein was higher than 10.5 as determined by chromatofocusing. The pure rape protein appeared furthermore to be able to transfer several phospholipids (phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine) between membranes. The rape protein, having a multifunctional property, was thus called acyl-binding/lipid-transfer protein (AB-LTP). In order to compare this protein to plant lipid-transfer proteins (LTPs), its structure was determined. The amino acid analysis of the rape AB-LTP revealed a high amount of alanine, an absence of histidine and tryptophan and the presence of eight cysteine residues. The N-terminal amino acid sequence of the rape protein revealed a high homology to plant LTPs. These observations led us to propose that the rape AB-LTPs belong to a category of plant proteins interacting with lipids and playing a role in the fatty acid dynamics.     

Induced decomposition of an acrylic peroxide for chemical modification of polypropylene

The heating of a mixture of ethyl 2-(1,1-dimethylethylperoxymethyl)propenoate and atactic polypropylene allowed the grafting of ester and epoxide functions onto the polyolefin. This is attributed to an induced decomposition of this acrylic peroxide, due to the addition of macroradicals, arising from polypropylene, to the unsaturation followed by an S_Hi onto the peroxidic bond.     

Effect of the Temperature Conditions of Sulfation Process on Extraction of Rare-Earth Metals from Refractory Ore

Metallurgist - Physical and chemical testing of sulfate product, obtained as a result of high-temperature treatment of ore from the Kundybai field with sulfuric acid mixture at 500°C revealed...     

Impacts of water level changes in the fauna,flora and physical properties over the Balkhash Lake watershed

The water level variations of the Lake Balkhash, the Kapshagay Reservoir and the Ili River and the linkage with salinity and biological conditions are investigated in this work using different techniques: satellite radar altimetry, in situ gauges, historical archives of fish population counting and field works. We show that it is possible now to monitor, over decades, in near real time, with high precision, the water level changes in the Lake Balkhash from satellite altimetry, over the reservoir and also along the Ili River. The vulnerability of the lake fauna and flora populations is enhanced by the morphometry of the lake: shallow and separation of the eastern basin from the western basin through the narrow Uzun‐Aral strait. Water policy of the Ili River also plays a fundamental role in the evolution of the Balkhash Lake. The Ili River that provides 80% of the surface water of the lake is a transboundary river. Development of intense irrigated agriculture in the upstream part of this river, located in the Chinese territory, could lead in the future to high hydrological stress in the downstream regions with potentially high damage in the delta and for fishery production. We show here the recent evolution of the Lake Balkhash basin from satellite data. Some interannual oscillation of 6–8 years over the last decade has been highlighted, with a water level of the lake still at a high value, but prediction on increasing irrigation is also highlighting the vulnerability of this lake. Linkage between water level change along the river and the downstream waters is also investigated. It shows that the role of the reservoir is not fundamental in the understanding of the Lake Balkhash water level changes which is in contrast highly correlated to upstream river level changes.