Ordering within precipitates in copper-nickel-titanium alloys

The precipitation process in alloys containing 4% Ti and 5 to 16% Ni was investigated using transmission electron microscopy, hardness and electrical conductivity measurements. After ageing, spherical -Ni₃Ti precipitates with ordered DO₂₂ superlattice were observed in alloys CuTiNi5 to 10 and the L1₂ superlattice in the CuTi4Ni16 alloy. With increasing nickel content the size of precipitates decreases; this has only a minor influence on the age hardening. The CuTiNi10 alloy has the best electrical conductivity approaching 18m^–1mm^–2.     

Finding Induced Paths of Given Parity in Claw-Free Graphs

The Parity Path problem is to decide if a given graph contains both an induced path of odd length and an induced path of even length between two specified vertices. In the related problems Odd Induced Path and Even Induced Path, the goal is to determine whether an induced path of odd, respectively even, length between two specified vertices exists. Although all three problems are NP-complete in general, we show that they can be solved in $\mathcal{O}(n^{5})$ time for the class of claw-free graphs. Two vertices s and t form an even pair in G if every induced path from s to t in G has even length. Our results imply that the problem of deciding if two specified vertices of a claw-free graph form an even pair, as well as the problem of deciding if a given claw-free graph has an even pair, can be solved in $\mathcal{O}(n^{5})$ time and $\mathcal{O}(n^{7})$ time, respectively. We also show that we can decide in $\mathcal{O}(n^{7})$ time whether a claw-free graph has an induced cycle of given parity through a specified vertex. Finally, we show that a shortest induced path of given parity between two specified vertices of a claw-free perfect graph can be found in $\mathcal {O}(n^{7})$ time.     

Iron-ruthenium catalyst for the water-gas shift reaction

Iron-ruthenium catalysts prepared by impregnation of calcination products of -, , -and -iron oxide-hydroxides with either ruthenium chloride or ruthenium red were tested for the activity for the water-gas shift reaction. The effect of support, ruthenium containing impregnation agent and thermal treatment on catalyst performance was discussed.     

Quantitative microstructural characterisation of Fe–30Ni alloy after martensitic transformations by means of stereological and magnetic methods

In the Fe–30Ni alloy investigated a martensitic transformation can occur both during quenching or plastic deformation. Martensite formed during plastic deformation, depending on the thermo-mechanical treatment applied, exhibits a different morphology from that achieved during quenching and forms the so-called composite-like structure. The morphology and volume fraction of martensite depends both on strain and temperature. In the present studies Fe–30Ni alloy was deformed by monotonic rolling in one path and perpendicular rolling in the temperature range M_D–M_S. The aim of the investigations was a determination of martensite volume fraction depending on the strain and temperature. To examine the influence of strain, the alloy was deformed by rolling in one path or perpendicular rolling at a temperature of − 30 °C, in the strain range of 10–30%. The dependence of temperature was investigated by rolling with 30% strain in a temperature range from − 30 °C to − 80 °C. The variants of thermo-mechanical treatment performed enabled us to achieve different martensite morphologies and volume fractions. Microstructural analysis was performed by means of light microscopy and transmission electron microscopy. The results of quantitative microstructural analysis of martensite and retained austenite volume fractions formed in different thermo-mechanical treatments were compared with those obtained by magnetic measurements. The fraction of deformation-induced martensite determined varied from 2% to 86%. The partial volume fractions V_V^MF of martensite formed in different deformation directions were also determined. It was found that the influence of the temperature on the martensite volume fraction is more pronounced than the influence of strain.     

Quattor: Tools and Techniques for the Configuration,Installation and Management of Large-Scale Grid Computing Fabrics

This paper describes the quattor tool suite, a new system for the installation, configuration, and management of operating systems and application software for computing fabrics. At present Unix derivatives such as Linux and Solaris are supported. Quattor is a powerful, portable and modular open source solution that has been shown to scale to thousands of computing nodes and offers a significant reduction in management costs for large computing fabrics. The quattor tool suite includes innovations compared to existing solutions which make it very useful for computing fabrics integrated into grid environments. Evaluations of the tool suite in current large scale computing environments are presented.     

Concurrent analogue fault simulation,the equation formulation aspect

Fault simulation is an essential tool for developing test patterns for circuits. Because the potential number of faults in a circuit is potentially very large, computational efficiency is an important consideration. In the digital domain, concurrent fault simulation is well‐established as an efficient tool. For analogue circuits, fault simulation is often performed by repeated insertion of possible faults and resimulation of the circuit. Consequently, methods for efficient concurrent analogue fault simulation are attracting attention. A review of existing methods of concurrent analogue fault simulation shows that most are based on a similar fundamental perturbation of the original fault‐free circuit equations, although the methods differ in the procedure applied after the circuit equations are formulated. We develop here a comprehensive set of element stamps, describing faulty elements, enabling effective and routine equation formulation for faulty circuits. These may be used no matter what method of fault simulation is later applied. These stamps are used in a new technique for concurrent analogue fault simulation, based on modified nodal analysis. A significant improvement in efficiency, compared with other methods, is demonstrated. Copyright © 2004 John Wiley & Sons, Ltd.     

Constraint Lingo: towards high‐level constraint programming

Logic programming requires that the programmer convert a problem into a set of constraints based on predicates. Choosing the predicates and introducing appropriate constraints can be intricate and error prone. If the problem domain is structured enough, we can let the programmer express the problem in terms of more abstract, higher‐level constraints. A compiler can then convert the higher‐level program into a logic‐programming formalism. The compiler writer can experiment with alternative low‐level representations of the higher‐level constraints in order to achieve a high‐quality translation. The programmer can then take advantage of both a reduction in complexity and an improvement in runtime speed for all problems within the domain. We apply this analysis to the domain of tabular constraint‐satisfaction problems. Examples of such problems include logic puzzles solvable on a hatch grid and combinatorial problems such as graph coloring and independent sets. The proper abstractions for these problems are rows, columns, entries, and their interactions. We present a higher‐level language, Constraint Lingo, dedicated to problems in this domain. We also describe how we translate programs from Constraint Lingo into lower‐level logic formalisms such as the logic of propositional schemata. These translations require that we choose among competing lower‐level representations in order to produce efficient results. The overall effectiveness of our approach depends on the appropriateness of Constraint Lingo, our ability to translate Constraint Lingo programs into high‐quality representations in logic formalisms, and the efficiency with which logic engines can compute answer sets. We comment on our computational experience with these tools in solving both graph problems and logic puzzles. Copyright © 2004 John Wiley & Sons, Ltd.