bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computability and Adaptivity inCFD
Authors: Hoffman J. , Johnson C. 
Published: January 2005

AbstractWe present an approach to Computational Fluid Dynamics CFD based on adaptive stabilized Galerkin finite element methods with duality based a posteriori error control for chosen output quantities of interest. We address the basic question of computability in CFD: For a given flow, what quantity is computable to what tolerance to what cost? We focus on incompressible Newtonian flow with medium to large Reynolds numbers involving both laminar and turbulent flow features. Our basic tool is a representation formula for the error in the quantity of interest in terms of a space–time integral of the residual of a computed solution multiplied by weights related to derivatives of the solution of an associated linear dual problem with data connected to the output. We use the error representation formula to derive an a posteriori error estimate combining residuals with computed dual weights, which is used for mesh adaptivity in space–time with the objective of satisfying a given error tolerance with minimal computational effort. We show in concrete examples that outputs, such as mean values in time of drag and lift of turbulent flow around a bluff body are computable on a PC with a tolerance of a few percent using a few hundred thousand mesh points in space. We refer to our methodology asAdaptive DNS/LES, where automatically by adaptivity certain features of the flow are resolved in a Direct Numerical Simulation DNS, while certain other small‐scale turbulent features are left unresolved in a Large Eddy Simulation LES. The stabilization of the Galerkin method giving a weighted least square control of the residual acts as the subgrid model in the LES. The a posteriori error estimate takes into account both the error from discretization and the error from the subgrid model.
Dynamic Multilevel Methods and Turbulence
Authors: Dubois T. , Jauberteau F. , Temam R. M. 
Published: January 2005

AbstractIn this article, we describe numerical multilevel methods applied to the Navier–Stokes equations (homogeneous isotropic turbulence and channel flow problem), to the shallow water equations (geophysical problems), and to the renormalization of small eddies. The first difficulties with multilevel methods is to separate the scales. In this work, various cases are considered: the case of spectral methods, the case of finite difference methods, and the case of finite element methods. Then the numerical treatment is adapted to the size of the computed scales. The aim is to obtain new schemes, with better modeling properties and improved numerical stability. The spectral case is studied in detail, and results of numerical simulations are reported in this case.Multilevel numerical methods are indispensable for the approximation of phenomena involving a large number of scales, such as turbulence. Although the methods described in this article are generally limited to two levels, they can, as explained in the text, be extended to a more important number of levels, thus extending significantly their performances.
Turbulence Direct Numerical Simulation and Large‐Eddy Simulation
Authors: Sagaut Pierre 
Published: January 2005

AbstractThis article deals with direct numerical simulation and large‐eddy simulation of turbulent flows, which are two techniques for the unsteady three‐dimensional simulation of turbulent motion. For the sake of clarity and brevity, the present framework is restricted to Newtonian, single‐phase, single‐specie fluids. Both compressible and incompressible cases are considered. Numerical requirements for these two approaches are discussed, including grid resolution and control of numerical errors. The specific problem of compressible flows with shocks is detailed. The problem of the definition of the filtering procedure and subgrid models for the large‐eddy simulation approach is presented, and the main theoretical and practical solutions are given. The difficult question of the definition of boundary conditions is also considered, with emphasis on turbulent inflow conditions and wall stress models. The last section is devoted to the presentation of the evolution of the application of these two techniques.
Aerodynamics
Authors: Jameson Antony 
Published: January 2005

AbstractComputational methods are now pervasive in the science of aerodynamics. Because previously existing numerical methods proved inadequate for fluid flow simulations, the emergence of computational fluid dynamics (CFD) as a distinct discipline has sparked the development of an entirely new class of algorithms and a supporting body of theory, which are the main theme of this article. After a review of mathematical models of fluid flow, methods for solving the transonic potential flow equation (of mixed type) are examined. The central part of the article discusses the formulation and implementation of shock‐capturing schemes for the Euler and Navier–Stokes equations. The article next discusses the merits of the contrasting approaches of finite difference, finite volume, and finite element methods for the treatment of flows in complex geometric domains, together with the treatment of boundary conditions. A detailed presentation of explicit and implicit time‐stepping schemes for both steady and unsteady flows precedes a discussion of preconditioning and multigrid procedures for accelerating the convergence of steady state calculations. Dual time‐stepping schemes are recommended for the simulation of unsteady flow. In order to realize the potential benefits of CFD, it is essential to move beyond simulation to aerodynamic (and ultimately multidisciplinary) optimization. The article concludes with a discussion of aerodynamic shape optimization via control theory.
Combustion
Authors: Poinsot T. J. , Veynante D. P. 
Published: January 2005

AbstractThis chapter describes the basic phenomena controlling reacting flows and the corresponding computational methodologies. Combustion regimes (premixed or diffusion flames, laminar or turbulent cases, stable or unstable behavior) are first defined before introducing the basic terminology required to understand numerical techniques for reacting flows. The governing equations for combustion are more complex than those used in classical aerodynamics, and their specificities are discussed before describing numerical methods for laminar flames. Finally, the various methods used for turbulent flames are discussed, focusing on recent techniques such as Direct Numerical Simulations and Large Eddy Simulations.
Direct adaptive active noise control algorithms in case of uncertain secondary path dynamics
Authors: Kohno Toshikazu , Sano Akira 
Published: January 2005

AbstractAlmost all adaptive feedforward control algorithms for active noise control require an identified model of the secondary path dynamics from the control loudspeaker to the error and reference microphones. This paper is concerned with new direct adaptive algorithms which will be applicable when the secondary path dynamics are unknown or uncertainly changeable. In the first approach, the control algorithm consists of a robust adaptive feedforward control algorithm and robust feedback control scheme permitting bounded uncertainty in the nominal secondary path model. The second one is a fully direct adaptive feedforward control algorithm which does not require explicit identification of the secondary path dynamics even when all of the path dynamics are uncertain. Simulation and experimental results validate the effectiveness of the proposed algorithms. Copyright © 2005 John Wiley & Sons, Ltd.
Compartmental modelling of the uptake kinetics of the anti‐cancer agent topotecan in human breast cancer cells
Authors: Evans Neil D. , Errington Rachel J. , Chapman Michael J. , Smith Paul J. , Chappell Michael J. , Godfrey Keith R. 
Published: January 2005

AbstractA compartmental model for the in vitro uptake kinetics of the anti‐cancer agent topotecan is proposed. This model provides a description of the activity of the drug, and subsequent delivery of active form to the nuclear DNA target. The unknown model parameters are estimated from two‐photon laser‐scanning microscopy data, which provide concentrations of topotecan (active plus inactive forms) in the extracellular region containing live human breast tumour cells (MCF‐7 cell line), the cytoplasm and the nucleus. This determines an output structure for which the model is uniquely identifiable, that is, the unknown parameters are uniquely determined from noise‐free, continuous and perfect data. The model allows in silico predictions of the dose dependence of target binding. Copyright © 2005 John Wiley & Sons, Ltd.
CHARGE syndrome from birth to adulthood: An individual reported on from 0 to 33 years
Authors: Searle Lisa C. , Graham John M. , Prasad Chitra , Blake Kim D. 
Published: January 2005

AbstractCHARGE syndrome was independently reported by Hall [(1979): J Pediatr 95:395–398] and Hittner et al. [(1979): J Pediatr Ophthalmol Strabismus 16:122–128] and was initially considered to be a non‐random association between distinct multiple congenital anomalies. It is now considered to be a recognizable syndrome with well‐characterized diagnostic criteria and a genetic pathogenesis. We report on a 33‐year‐old adult male with CHARGE syndrome, with emphasis on the unique medical, behavioral, and psychological issues faced in adulthood. Characteristic facial and ear abnormalities were obvious in early childhood, and bilateral retinal colobomata, left choanal atresia, right congenital hip dislocation, and hypogonadism were diagnosed during the first year. Walking was delayed due to vestibular problems, speech was impaired due to moderately severe hearing loss, and use of sign communication was limited. Choanal atresia was surgically corrected in infancy, and atrial septal defect, ventricular septal defect, and patent ductus arteriosus were surgically corrected in childhood. Undescended testes were removed in adolescence, and gallstones were removed in early adulthood. Puberty was delayed until hormone replacement therapy began at 15 years. Behavioral disturbances and anxiety persisted throughout childhood, adolescence, and into adulthood, often resulting from communication challenges. At 33 years of age, he lives independently in a supervised group home, receives regular eye check‐ups and is being monitored for severely reduced bone density. © 2005 Wiley‐Liss, Inc.
Familial cognitive deficits in schizophrenia
Authors: Hoff Anne L. , Svetina Christine , Maurizio Andrea M. , Crow Timothy J. , Spokes Kate , DeLisi Lynn E. 
Published: January 2005

AbstractSusceptibility to schizophrenia is considered familial, but the mechanism for transmission has not been found. Since widespread cognitive deficits have been found in patients with schizophrenia, several of these have been proposed as candidate familial endophenotypes that may or may not be predictive of who develops the illness. The current study examines these candidates in individuals from 32 families with at least 2 members having the diagnosis of chronic schizophrenia and normal comparison subjects using an extensive neuropsychological battery. Consistent with previous literature, family members with schizophrenia were significantly impaired on all measures compared with controls. Well relatives demonstrated significantly worse performance on a measure of verbal learning, delayed visual recall, perceptual‐motor, and pure motor speed. Expressive and receptive language, but not other functions, were highly correlated within both concordant for schizophrenia and discordant sibling pairs, suggesting that they are familial vulnerability endophenotypes, but not predictive of whom becomes ill. On the other hand, some measures of perceptual‐motor, pure motor speed, and frontal/executive functioning were significantly correlated in concordant, but not discordant pairs. These latter correlations suggest that some cognitive measures may be genetically related to the illness. © 2004 Wiley‐Liss, Inc.
Compounds of arsenic, antimony, and tin in mollusc shells
Authors: Cullen William R , Dodd Mathew , Nwata Basil U , Reimer Deborah A , Reimer Kenneth J 
Published: January 2005

AbstractInorganic arsenic(III) and arsenic(V), methyl‐arsenicals, antimony(III), and antimony(V), and butyltin derivatives are present in the shells of molluscs found in the coastal waters of British Columbia.
Triphenylstibine oxide–phosphorus(V) sulfide as a novel condensation catalyst system: application to the synthesis of dipeptides
Authors: Nomura Ryoki , Yamada Yasuhiro , Matsuda Haruo 
Published: January 2005

AbstractTriphenylstibine oxide (Ph3SbO) and phosphorus(V) sulfide (P4S10) synergistically catalyzed the aminolysis of N‐protected amino‐acids with amino‐acid esters in benzene. Ph3SbO accelerated both the initial conversion of carboxylic moieties into the corresponding thiocarboxylic moieties by P4S10 and the subsequent aminolysis of the resulting thiocarboxylic acids. Thus, dipeptides such as Z–A–A′–OEt (where Z = PhCH2OC(O)– and A,A′ = Ala,Gly; Gly,Gly; Leu,Gly; Phe,Gly; Phe,Leu;Ser,Gly; Val,Gly, respectively) were conveniently prepared even at 35°C.
Dimethylheptyl [3‐(N‐hetaryl)propyl]silanes: Synthesis, antimicrobial and antiblastic activity
Authors: Sturkovich R , Goldberg Yu , Verovsky V , Augustane I , Prodanchuk N , Deineka S , Lukevics E 
Published: January 2005

AbstractThe alkylation of monoazoles, diazoles, triazoles and tetrazoles with dimethylheptyl(3‐iodopropyl)silane using liquid/liquid phase‐transfer catalysis affords the corresponding [3‐(N‐azolyl)propyl]silanes in high yield, by which means the nonsymmetric ambident heterocycles 1,2,4‐triazole and tetrazole undergo alkylation regiospecifically in position 1 and 2, respectively. Dimethylheptyl[3‐(N‐imidazolyl)propyl]silane demonstrated high fungistatic activity with respect to S. cerevisiae and T.rubrum in combination with high cytotoxicity.
Persistence of fungitoxicity of two triorganotin(IV) compounds in soil
Authors: Kuthubutheen A J , Wickneswari R , Kumar Das V G 
Published: January 2005

AbstractThe persistence of triphenyltin chloride‐triphenylphosphine oxide (Ph3SnCl·Ph3PO) and diphenylbutyltin bromide (Ph2BuSnBr) in unsterilized sandy loam soil maintained in the dark at 60% of its water‐holding capacity and at 27±2°C was studied over a period of 29 days. The percentage recovery of the compounds upon extraction with acetone immediately after application to soil was 60% for Ph3SnCl·Ph3PO and 9.8% for Ph2BuSnBr. The half‐lives of the compounds were 15 days for Ph3SnCl·Ph3PO and 14.2 days for Ph2BuSnBr. After 29 days following application of the compounds in soil < 8.3 μg g−1 of Ph3SnCl·Ph3PO and < 5.1 μg g−1 of Ph2BuSnBr remained in soil compared with the starting concentration of 50 μg of each compound per gram soil. The two triorganotin compounds were evidently easily degraded and the compounds may be applied every 2–3 weeks in the field at a rate of at least 0.005–0.01 kg ha−1.
A kinetic model for the growth of znte by metal organic chemical vapour deposition
Authors: Dumont Hervé , Qu'hen Bruno , Bourée Jean Eric , Gorochov Ouri , Marbeuf Alain 
Published: January 2005

AbstractA kinetic model for the metal organic chemical vapour deposition (MOCVD) growth of ZnTe is presented, taking into account the competitive adsorption of organometallic precursors. By assuming that diethylzinc (DEZn) and diethyltellurium (DETe) or di‐isopropyltellurium (DIpTe) are adsorbed onto the surface by two sites, the model yields the growth rate as a function of the gas‐phase concentrations of the constitutents and is corroborated by experimental results obtained by the MOCVD growth (at 400°C with DETe or 350°C with DIpTe), which shows asymmetric behaviour: for a given DETe or DIpTe pressure (10−4 atm), the growth rate as a function of DEZn partial pressure passes through a maximum, whereas, at the same constant DEZn pressure, the growth rate increases monotonically when the DETe or DIpTe partial pressure increases
Some further observations on polymethylsilane as a precursor for silicon carbide
Authors: Mu Ying , Harrod John F. , Laine Richard M. 
Published: January 2005

AbstractPoly(methylsilanes) produced by sodium coupling of methyldichlorosilane (2:1 molar ratio) contain residual chlorine which can be removed by reduction with LiAlH4 at low temperature. Following this reduction, the polymers contain catalytically active centers (presumed to be silyl anions) which, in THF solution, further polymerize and crosslink the polymer at room temperature, while in toluene solution they are inactive. The reduced polymethylsilane gives high yields (ca 75%) of ceramic product on pyrolysis, but the composition is rich in silicon, compared with pure silicon carbide (SiC). Addition of catalytic amounts of dimethylzirconocene (DMZ) to this polymer gives a product which pyrolyzes to a product with stoichiometry close to that of SiC. It is concluded that the DMZ has an important influence in promoting Si–C bond formation, relative to Si–Si bond formation, during the pyrolysis.
Dibutyltin‐3‐hydroxyflavone titrates a dissociable component (cofactor) of mitochondrial ATP synthase: An energy‐transfer component linked to the ubiquinone pool
Authors: Griffiths David E. 
Published: January 2005

AbstractDibutyltin‐3‐hydroxyflavone, Bu2Sn(of), is a new fluorescence probe inhibitor of F1F0‐ATPase and oxidative phosphorylation which inhibits by titration of an unidentified component of F0. Its site of action is closely related to that of the trialkyltins and of venturicidin. This F0 component is part of a pool of this component which is present in the heart mitochondrial inner membrane at levels of 5–7 nmol (mg protein)−1 [18 ± 3 Bu2Sn(of) sites per mol F1F0‐ATPase]. However, ATPase activity in submitochondrial particles is near maximally inhibited by titration of approx. three Bu2Sn(of) sites per mol F1F0‐ATPase.Over 60% (60–80%) of the Bu2Sn(of) interaction sites can be lost during the purification of F1F0‐ATPase from submitochondrial particles. The number of Bu2Sn(of) interaction sites in various F1F0‐ATPase preparations is variable. The high numbers of Bu2Sn(of) sites per mol F1F0‐ATPase for heart mitochondria (18–21) and submitochondrial particles (15–19.5) decline in ATP synthase (11–15) to the low values obtained in Complex V (7–10.5) and the minimal values observed in highly purified F1F0−ATPase (3.5–5.6), thus indicating a variable dissociable component or cofactor of ATP synthase.The Bu2Sn(of) interaction site, a component of ATP synthase, is responsive to the redox status of the respiratory chain and the interaction with Bu2Sn(of) is with the reduced form of this component. Fluorescence titration studies show that this component is in redox equilibrium with the ubiquinone pool of the respiratory chain. It is proposed that this redox component serves as an inhibitor titratable cofactor pool which cycles through an F0 interaction site (or sites) via a system which serves as an energy‐transfer link between the respiratory chain and ATP synthase.
o‐Cyclohexadiamine complexes of some diorganotin, mono‐organtotin and stannic carboxylates: Synthesis and spectral properties
Authors: Bonire Josiah J. , Crowe Alan J. , Smith Peter J. 
Published: January 2005

Abstracto‐Cyclohexadiamine (the base component of tetraplatin) adducts of Ph2Sn(OCOCH3)2, nBu2Sn(OCOH3)2, (PhCH2)2Sn(OCOCH3)2, PhSn(OCOCF3)3, BuSn(OCOCH3)3 and Sn(OCOCH3)4 have been synthesized and characterized by elemental analysis and spectroscopy. The compounds appear to be the first such adducts in their class.
Substituent effects on titanocenium catalysts
Authors: Kucht Andreas , Kucht Homa , Song Wei , Rausch Marvin D. , Chien James C. W. 
Published: January 2005

AbstractTitanocene dichloride (1) and its bis(trifluoromethyl) (2) and bis(N,N‐dimethylamino) (3) derivatives have been compared as catalysts for ethylene and propylene polymerizations using both methylaluminoxane (MAO) and triphenylcarbenium tetrakis(pentafluorophenyl)borate (4)/triisobutylaluminum (TIBA) as cocatalysts. The differences between the activities of the three ‘free’ titanocenium ions and the Mw of the polyolefins produced by them may be attributable to the relative stabilities of the intermediate olefin–titanocenium π‐complexes. Interaction of either the neutral MAO or its anion with the titanocenium species may be responsible for the significantly lower catalytic efficiencies when the precursors were activated by MAO than by the 4/TIBA system.
Short‐term bioconcentration and distribution of methylmercury, tributyltin and corresponding inorganic species in the starfish leptasterias polaris
Authors: Rouleau Claude , Pelletier Émilien , Tjälve Hans 
Published: January 2005

AbstractStarfish, Leptasterias polaris, were exposed between 30 min and 48 h to seawater containing 0.25 nmol dm−3 of radiolabelled methylmercury (Me203HgCI), tributyltin [(C4H9)3113SnCI], and inorganic 203HgCI2 and 113SnCI4, with the objectives of comparing the uptake and distribution kinetics of these metal species in organs and tissues of treated organisms. Some starfish exposed to metals for 48 h were allowed to depurate for 24 h in clean seawater. Whole‐body autoradiography was used to locate radiotracers very precisely within starfish tissues. The total amount of methylmercury (MeHg) accumulated in the whole animal after 48 h reached 0.53 nmol compared with 0.09 nmol for inorganic mercury, while tributyltin (TBT) reached 0.72 nmol compared with 0.017 nmol for inorganic tin. No significant reduction of body burdens occurred during the depuration period. The first‐order rate constant characterizing the uptake of metals by whole animals, k1, ranged from 0.102 h−1 for MeHg to 3.6 × 10−3h−1 for inorganic mercury(II) and to 8.4 × 10−4 h−1 for inorganic tin(IV). The first‐order rate constant characterizing the translocation of metals from seawater‐exposed tissues toward internal organs, k3, was available for inorganic Hg and Sn and had values similar to k1. Concentration ratios between external tissues and internal organs after a 48 h exposure were 11.5 and 25.4 for MeHg and TBT, respectively, and 2.1 and 6.1 for inorganic mercury and tin. Furthermore, autoradiograms showed that MeHg and TBT were accumulated only on the external surface of the body wall and podia. This finding indicates a much slower translocation process for organometallic species than inorganic species, a process which seems to be related to the binding mode of MeHg and TBT to the organic matrix of external tissues of starfish.