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11.
In this paper, the locally conservative Galerkin (LCG) method (Numer. Heat Transfer B Fundam. 2004; 46 :357–370; Int. J. Numer. Methods Eng. 2007) has been extended to solve the incompressible Navier–Stokes equations. A new correction term is also incorporated to make the formulation to give identical results to that of the continuous Galerkin (CG) method. In addition to ensuring element‐by‐element conservation, the method also allows solution of the governing equations over individual elements, independent of the neighbouring elements. This is achieved within the CG framework by breaking the domain into elemental sub‐domains. Although this allows discontinuous trial function field, we have carried out the formulation using the continuous trial function space as the basis. Thus, the changes in the existing CFD codes are kept to a minimum. The edge fluxes, establishing the continuity between neighbouring elements, are calculated via a post‐processing step during the time‐stepping operation. Therefore, the employed formulation needs to be carried out using either a time‐stepping or an equivalent iterative scheme that allows post‐processing of fluxes. The time‐stepping algorithm employed in this paper is based on the characteristic‐based split (CBS) scheme. Both steady‐ and unsteady‐state examples presented show that the element‐by‐element formulation employed is accurate and robust. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
12.
Francesco De Matteis Gwyn A. Lord 《Rapid communications in mass spectrometry : RCM》2008,22(24):4055-4065
We have used open‐chain tetrapyrroles, such as bilirubin, as molecular probes to investigate the pro‐oxidant activity of desferrioxamine (DES) and its modulation by Trolox. On exposure to Fe‐EDTA/H2O2, bilirubin and mesobilirubin underwent bleaching. When DES was present, bleaching was prevented and both rubins were converted into green‐coloured derivatives and then into red pigments. Trolox added with DES inhibited the colour changes induced by DES. The oxidative products were resolved from their parent compounds by high‐performance liquid chromatography (HPLC) and studied by electrospray ionization mass spectrometry and by UV/visible spectroscopy. The green products were identified as biliverdin or mesobiliverdin; the red pigments as the 1:1 molar adduct of DES with biliverdin or mesobiliverdin, less two hydrogens in both cases. It is concluded that DES exercises its oxidative activity through nitroxyl oxidizing radicals capable of efficient hydrogen abstraction, dehydrogenating either rubin to the corresponding verdin. A diradical derivative of DES (bearing two nitroxyl radicals in the same molecule) may be involved in the oxidation of verdins to red pigments, through concerted dehydrogenation and adduct formation. These results shed further light on the redox properties of bilirubin, DES and Trolox, and their interactions. They provide further evidence of the pro‐oxidant activity of DES and suggest a more general biological significance, as rapid removal of bilirubin by bleaching or dehydrogenation may have pharmacological/toxicological implications in severe jaundice. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
13.
W. G. Campbell J. C. Mc Gowan St. A. Bryant A. J. Bailey A. Orup R. I. Thieme H. Bergström K. G. Trobeck P. W. Moryganow J. I. Wlassjuk N. K. Koshewnikowa G. S. Ssurta G. Jayme H. Pfretzschner R. Steinmann M. G. van Beckum G. J. Ritter J. H. Barbour C. F. Cross und E. J. Bevan 《Fresenius' Journal of Analytical Chemistry》1940,119(1-2):67-71
Ohne Zusammenfassung 相似文献
14.
Everett WN Beltran-Villegas DJ Bevan MA 《Langmuir : the ACS journal of surfaces and colloids》2010,26(24):18976-18984
We report video microscopy measurements and inverse simulation analyses of specific Ca(2+)-dependent interactions between N-cadherin fragments attached to supported lipid bilayer-coated silica colloids in quasi-2D concentrated configurations. Our results include characterization of the bilayer formation and fluidity and the attachment of active extracellular cadherin fragments on bilayers. Direct measurements of interaction potentials show nonspecific macromolecular repulsion between cadherin fragments in the absence of Ca(2+) and irreversible bilayer fusion via cadherin-mediated attraction at >100 μM Ca(2+). Analysis of Ca(2+)-dependent N-cadherin bond formation in quasi-2D concentrated configurations using inverse Monte Carlo and Brownian Dynamics simulations show measurable attraction starting at 0.1 μM Ca(2+), a concentration significantly below previously reported values. 相似文献
15.
Melissa M. Cadelis Hugo Gordon Alex Grey Soeren Geese Daniel R. Mulholland Bevan S. Weir Brent R. Copp Siouxsie Wiles 《Molecules (Basel, Switzerland)》2021,26(11)
Fungi have become an invaluable source of bioactive natural products, with more than 5 million species of fungi spanning the globe. Fractionation of crude extract of Neodidymelliopsis sp., led to the isolation of a novel polyketide, (2Z)-cillifuranone (1) and five previously reported natural products, (2E)-cillifuranone (2), taiwapyrone (3), xylariolide D (4), pachybasin (5), and N-(5-hydroxypentyl)acetamide (6). It was discovered that (2Z)-cillifuranone (1) was particularly sensitive to ambient temperature and light resulting in isomerisation to (2E)-cillifuranone (2). Structure elucidation of all the natural products were conducted by NMR spectroscopic techniques. The antimicrobial activity of 2, 3, and 5 were evaluated against a variety of bacterial and fungal pathogens. A sodium [1-13C] acetate labelling study was conducted on Neodidymelliopsis sp. and confirmed that pachybasin is biosynthesised through the acetate polyketide pathway. 相似文献
16.
Jonathan Bevan 《Comptes Rendus Mathematique》2003,336(1):11-14
We construct a C1,1 polyconvex function W such that there exists a fixed 2×2 matrix Y with the property that all convex representatives of W have at least two distinct subgradients (and are hence not differentiable) at the point (Y,detY), showing in particular that a polyconvex function can be smoother than any of its convex representatives. To cite this article: J. Bevan, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
17.
A kinetic investigation of electronically excited arsenic atoms in the low-lying states, As(4p3 2DJ) and As(4p3 2PJ), ca. 1.33 and 2.28 eV, respectively, above the 44S3/2 ground state, has been carried out by atomic absorption spectroscopy. Atoms in these optically metastable states were generated by the pulsed irradiation of suitable arsenic compounds (AsMe3 for 2D and AsCl3 for 2P) in different spectral regions and monitored photoelectrically by time-resolved attenuation of atomic resonance radiation. Rate constants for the deactivation of these two states are reported for a range of collision partners. The data are compared with those of the analogous states of lighter atoms in group V, namely, P(32DJ, 32PJ) and N(22DJ, 22PJ), and discussed in terms of spin and orbital symmetry considerations. 相似文献
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20.
R. G. Bevan 《The Journal of the Operational Research Society》1980,31(3):201-208
The problems of public expenditure planning and control to which O.R. can make a contribution are identified. Suggestions are made for research by those in O.R. both within government and in universities. Recent work in the Treasury on financial models and information systems are discussed in terms of how such work might be applied elsewhere and extended to include measures of achievement. The topics covered include planning for uncertainty and theory development by O.R. in models of inflation and social justice. 相似文献