Steering in computational science: Mesoscale modelling and simulation

This paper outlines the benefits of computational steering for high performance computing applications. Lattice-Boltzmann mesoscale fluid simulations of binary and ternary amphiphilic fluids in two and three dimensions are used to illustrate the substantial improvements which computational steering offers in terms of resource efficiency and time to discover new physics. We discuss details of our current steering implementations and describe their future outlook with the advent of computational grids.     

On regularity of block triangular fuzzy matrices

Necessary and sufficient conditions are given for the regularity of block triangular fuzzy matrices. This leads to characterization of idempotency of a class of triangular Toeplitz matrices. As an application, the existence of group inverse of a block triangular fuzzy matrix is discussed. Equivalent conditions for a regular block triangular fuzzy matrix to be expressed as a sum of regular block fuzzy matrices is derived. Further, fuzzy relational equations consistency is studied.     

Z4-Kerdock Codes, Orthogonal Spreads, and Extremal Euclidean Line-Sets

When m is odd, spreads in an orthogonal vector space of type⁺(2m + 2,2) are related to binary Kerdock codes and extremalline-sets in 2^{m + 1} with prescribed angles. Spreads in a 2m-dimensionalbinary symplectic vector space are related to Kerdock codesover Z₄ and extremal line-sets in with prescribed angles. These connections involve binary, realand complex geometry associated with extraspecial 2-groups.A geometric map from symplectic to orthogonal spreads is shownto induce the Gray map from a corresponding Z₄-Kerdock codeto its binary image. These geometric considerations lead tothe construction, for any odd composite m, of large numbersof Z₄-Kerdock codes. They also produce new Z₄-linear Kerdockand Preparata codes. 1991 Mathematics Subject Classification:primary 94B60; secondary 51M15, 20C99.     

Probabilistic Inductive Classes of Graphs

A unifying framework—probabilistic inductive classes of graphs (PICGs)—is defined by imposing a probability space on the rules and their left elements from the standard notion of inductive class of graphs. The rules can model the processes creating real-world social networks, such as spread of knowledge, dynamics of acquaintanceships or sexual contacts, and emergence of clusters. We demonstrate the characteristics of PICGs by casting some well-known models of growing networks in this framework. Results regarding expected size and order are derived. For PICG models of connected and 2-connected graphs order, size and asymptotic degree distribution are presented. The approaches used represent analytic alternative to computer simulation, which is mostly used to obtain the properties of evolving graphs.     

碳税机制下考虑不同低碳策略的动态博弈模型及复杂性研究

考虑碳排放税,建立双寡头制造商分别实施废品回收和绿色低碳广告投入策略的动态博弈模型。通过系统稳定域,分岔图,功率谱等分析了博弈模型纳什均衡解处的稳定性及参数对系统稳定域的影响,同时对系统的复杂性特征进行了研究。结果表明,消费者回收价格敏感性增加会使整个系统稳定域缩小,而绿色低碳广告投入水平增加只会使实施该策略的企业自身稳定域扩大;当制造商价格调整速度过快时,系统会进入混沌状态;混沌状态下,对比实施广告策略的制造商,实施废品回收策略的制造商价格调整行为对市场造成的震荡更大。最后使用反馈控制策略对系统混沌状态进行了有效的控制,研究结果对制造商低碳策略选择及价格决策有着较好的借鉴意义。     

The bidentate behaviour of tetrahydroborate towards copper(II) and group(IV) metals in heterobimetallic complexes

Summary New heterobimetallic complexes of the type [Cu(TETA)-BH₄)₂M(BH₄)₂] (TETA = triethylene tetramine; M = Si, Ge, Sn, Ti and Zr) were prepared by the interaction of [Cu(TETA)Cl₂MCl₂] with an excess of KBH₄ in THF. The results indicate that the complexes are nonelectrolytes and the tetrahydroborate group links to the copper(II) atom and the group(IV) metal in a bidentate manner adopting C _2v symmetry.     

Chelating behaviour of new 12-membered Schiff base macrocycles containing pendant groups

Summary The free Schiff base macrocycles 1,4,7,10-tetraazacyclo-dodeca-5,6,11,12-tetraaminoacetic acid-4,6,10,12-tetraene (L¹), 1,4,7,10-tetraazacyclododeca-5,6,11,12-tetraamino-phenyl-4,6,10,12-tetraene (L²) and 1,4,7,10-tetraazacyclo-dodeca-5,6,11,12-tetraaminopyridyl-4,6,10,12-tetraene (L³) have been prepared by the reaction of oxamidediacetic acid, oxamidediphenyl and oxamidedipyridyl, respectively, with ethylenediamine. Their complexes with first row transition metal ions, of types [MLCl₂] and [MLCl₂]Cl, have also been prepared and characterized by physico-chemical and spectroscopic methods. The complexes of divalent metal ions are non-ionic while those of trivalent metal ions appear to be 11 electrolytes. An octahedral geometry is proposed for all the complexes.     

A pericyclic cascade to the stereocontrolled synthesis of 9-cis-retinoids

A domino reaction that is pericyclic in nature is thought to be triggered upon treatment of alkenynol 10 with arylsulfenyl chlorides. The process comprises an ordered sequence of sigmatropic rearrangements: a reversible [2,3]-allyl sulfenate to allyl sulfoxide shift, followed by a [2,3]-propargyl sulfenate to allenyl sulfoxide rearrangement, and last a stereodifferentiating [1,5]-sigmatropic hydrogen migration leading to polyene 13. The occurrence of the C7 to C11 hydrogen migration has been demonstrated by labeling experiments. The double diastereoselection of the [1,5]-sigmatropic hydrogen shift to afford a single isomer of the final polyene 13 is thought to arise from a combination of the electronic effect of the sulfoxide at one terminus, and the steric effect imparted by the bulky trimethylcyclohexenyl substituent at the other terminus. The overall process thus constitutes a stereoselective synthesis of an E,Z,Z-triene fragment from an alkenynol and, in particular, a retinoid with the 7E,9Z,11Z,13E configuration on the conjugated polyenic side chain. Application of this method to the synthesis of retinoids, including labeled analogues, is straightforward.     

Coordination properties of new indazole derivatives

Summary The bidentate nitrogen donor ligands 2-(1-indazolyl) pyridine and 2-(1-indazolyl) pyrimidine have been synthesised. Their complexes with Mn^II, Co^II, Ni^II, Cu^II and Zn^II have been prepared and characterised by elemental analysis, i.r., u.v. spectra and magnetic susceptibility measurements. The complexes are nonelectrolytes and have magnetic moments consistent with an octahedral environment.     

Ion Chromatographic Determination of Anions in Environmental Samples

Abstract

The use of ion-exchange chromatography with an IonPac AS 14 column, 3.5 mM Na₂CO₃/1.0 mM NaHCO₃ eluent and suppressed conductivity detection provides a simple, cost-effective, fast, accurate, and highly sensitive method for the determination of F^?, Cl^?, NO₂ ^?, Br^?, NO₃ ^?, PO₄ ^2?, SO₄ ^2?, and C₂O₄ ^2? at low μ/L levels in environmental samples. Data on sensitivity, selectivity, accuracy, and % relative standard deviation are described. The method is suitable for many environmental applications including atmospheric aerosols (exposed on cellulose, glass fiber, and quartz filters), rainwater, cloud water, potable- and non-potable waters, and carbonated waters. Dominant components of the aerosol were SO₄ ^2?, NO₃ ^?, and Cl^?. Rainwater, on the other hand, has relatively very low concentrations of these three species. The wide-spread concentration range for Cl^? in variety of water samples and the high concentrations for SO₄ ^2? in drinking water are striking. Determination of the anionic composition of carbonated waters revealed a considerable variation of the individual anions.