bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Thermodynamic Properties of Solutions of Polar Polymers. Theory
Authors: Yamakawa Hiromi , Rice Stuart A. , Corneliussen Roger , Kotin Leonard 
Published: January 2005

In this paper we present a simple analysis of the thermodynamic properties of solutions of polar polymers. It is found that:
(a) In the dilute solution regime, a cluster analysis identical with that used in the theory of solutions of nonpolar polymers can be developed, but with the thermodynamic parameter z now dependent on the dipole moment, dielectric constant, etc.
(b) In the concentrated solution regime, a continuum theory can be developed based on the assumption of uniform mixing of polymer chains and the use of cavity field and reaction field arguments.
(c) For dilute solutions of a polar polymer in a nonpolar solvent, or a nonpolarizable polar polymer in a polar solvent, the system is equivalent to an ordinary nonpolar polymer-poor solvent system.
(d) It is generally true that the solvent becomes poorer as the dipole moment and/or polarizability of the segment are increased. Also, the solvent becomes better as its dielectric constant increases.
(e) In the case of concentrated solutions of a polar polymer in a nonpolar solvent, the polar contribution to the Flory-Huggins free-energy parameter, χp, decreases with increasing concentration.
(f) In the case of concentrated solutions of a nonpolar polymer in a polar solvent, χp increases with increasing concentration.
(g) The dilute solution theory and concentrated solution theory predict the same functional form for χp in the limit of zero polymer concentration, but the numerical coefficients differ.
(h) The results of extensive digital computer calculations are presented in terms of the predicted concentration dependence of χp with varying properties of both polymer and solvent.
Agreement between theory and experiment is examined in detail in the following paper.
Meshfree Methods
Authors: Belytschko Ted , Rabczuk Timon , Huerta Antonio , Fernández‐Méndez Sonia 
Published: January 2005

AbstractThe aim of this chapter is to provide an in‐depth presentation and survey of meshfree particle methods. Several particle approximations are reviewed; the smooth particle hydrodynamic (SPH) method, corrected gradient methods, and the moving least squares (MLS) approximation. The discrete equations are derived from a collocation scheme or a Galerkin method. Special attention is paid to the treatment of essential boundary conditions. A brief review of radial basis functions is given because they play a significant role in meshfree methods. Finally, different approaches for modelling discontinuities in meshfree methods are described.
Adaptive Wavelet Techniques in Numerical Simulation
Authors: Cohen Albert , Dahmen Wolfgang , DeVore Ronald 
Published: January 2005

AbstractThis chapter highlights recent developments concerning adaptive wavelet methods for time dependent and stationary problems. The first problem class focuses on hyperbolic conservation laws in which wavelet concepts exploit sparse representations of the conserved variables. Regarding the second problem class, we begin with matrix compression in the context of boundary integral equations in which the key issue is now to obtain sparse representations of (global) operators like singular integral operators in wavelet coordinates. In the remainder of the chapter, a new fully adaptive algorithmic paradigm along with some analysis concepts are outlined, which, in particular, work for nonlinear problems and where the sparsity of both, functions and operators, is exploited.
Plates and Shells: Asymptotic Expansions and Hierarchic Models
Authors: Dauge Monique , Faou Erwan , Yosibash Zohar 
Published: January 2005

AbstractConcerning thin structures, such as plates and shells, the idea of reducing the equations of elasticity to two‐dimensional models defined on the midsurface seems relevant. Such a reduction was first performed thanks to kinematical hypotheses about the transformation of normal lines to the midsurface. As nowadays, the asymptotic expansion of the displacement solution of the three‐dimensional linear model is fully known at least for plates and clamped elliptic shells, we start from a description of these expansions in order to introduce the two‐dimensional models known as hierarchical models: These models extend the classical models, and presuppose the displacement to be polynomial in the thickness variable, transverse to the midsurface. Because of the singularly perturbed character of the elasticity problem as the thickness approaches zero, boundary, or internal layers may appear in the displacements and stresses, and so may numerical locking effects. The use of hierarchical models, discretized by higher degree polynomials (p‐version of finite elements) may help overcome these severe difficulties.
Multigrid Methods forFEMandBEMApplications
Authors: Hackbusch Wolfgang 
Published: January 2005

AbstractAfter discretization of the partial differential equations from mechanics, one usually obtains large systems of (non)linear equations. Their efficient solution requires the use of fast iterative methods. Multigrid iterations are able to solve linear and nonlinear systems with a rather fast rate of convergence, provided the problem is of elliptic type. The contribution describes the basic construction of multigrid methods, their ingredients, related methods, and their application to various problem classes.Although most of the applications concern FEM discretizations of partial differential equations, there are also applications to integral equations as they occur in boundary element methods (BEM).
Domain Decomposition Methods and Preconditioning
Authors: Korneev V. G. , Langer U. 
Published: January 2005

AbstractDomain decomposition methods nowadays provide powerful tools for constructing efficient parallel solvers for large‐scale systems of algebraic equations arising from the discretization of partial differential equations. The classical alternating Schwarz method and the classical substructuring technique have led to advanced overlapping and nonoverlapping domain decomposition solvers (preconditioners), that can be analyzed from a unified point of view now calledSchwarz theory. This survey article starts with a brief historical overview, provides the basic results of the Schwarz theory, looks at some overlapping domain decomposition methods (preconditioners) in brief, and discusses more extensively various nonoverlapping domain decomposition techniques.
Models and Finite Elements for Thin‐Walled Structures
Authors: Bischoff M. , Bletzinger K.‐U. , Wall W. A. , Ramm E. 
Published: January 2005

AbstractThe present study provides an overview of modeling and discretization aspects in finite element analysis of thin‐walled structures. Shell formulations based upon derivation from three‐dimensional continuum mechanics, the direct approach, and the degenerated solid concept are compared, highlighting conditions for their equivalence.Rather than individually describing the innumerable contributions to theories and finite element formulations for plates and shells, the essential decisions in modeling and discretization, along with their consequences, are discussed. It is hoped that this approach comprises a good amount of the existing literature by including most concepts in a generic format.The contribution focuses on nonlinear finite element formulations for large displacements and rotations in the context of elastostatics. Although application to dynamics and problems involving material nonlinearities is straightforward, these subjects are not taken into account explicitly.
Crystal Plasticity and Evolution of Polycrystalline Microstructure
Authors: Miehe Christian , Schotte Jan 
Published: January 2005

Abstract
The continuum slip theory of crystals provides a canonical framework of finite plasticity with physically well‐defined roots in the dislocation mechanics of metals. Reliable algorithmic settings of crystal plasticity are not only needed for structural analyses of single crystals but also provide a cornerstone for multiscale computations of evolving anisotropic microstructures in metallic polycrystals. This article summarizes a current status of computational crystal plasticity and its application to the texture analysis of polycrystals. It outlines a basic constitutive structure of crystal plasticity, alternative deformation‐driven stress update algorithms and a computational scheme for the nonlinear homogenization of polycrystalline aggregates. Particular emphasis is put on a canonical incremental variational formulation for Schmid‐type crystal plasticity with potential hardening where an incremental stress potential is obtained from a local minimization problem with respect to the internal variables. The existence of this stress potential allows the formulation of IBVPs for elastic–plastic crystals as a sequence of incremental minimization problems. Furthermore, the nonlinear homogenization of polycrystalline microstructures may be recast into a principle of minimum averaged incremental energy. Within this variational setting of homogenization, a quasi‐hyperelastic incremental macro‐stress potential is obtained from a global minimization problem with respect to the fine‐scale displacement fluctuation field. The performance of the formulations is demonstrated for benchmarks of single crystal plasticity and texture developments in polycrystals.
Computational Concrete Mechanics
Authors: Lackner Roman , Mang Herbert A. , Pichler Christian 
Published: January 2005

AbstractThis chapter contains a report on recent developments in the field of computational concrete mechanics, introducing the multiscale concept for the simulation of cement‐based materials and, in the case of reinforced concrete (RC), of the steel–concrete interaction. In this concept, several scales of observation may be considered simultaneously in the numerical analysis. Alternatively, material properties, which serve as input for macroscopic analyses, are related to properties of material phases and their assemblage at finer scales of observation. The benefits of multiscale approaches in computational concrete mechanics are illustrated by two analyses of real‐life structures employing macroscopic material properties for plain and reinforced concrete related to finer scales of observation.
Acoustics
Authors: Thompson Lonny L. , Pinsky Peter M. 
Published: January 2005

AbstractState‐of‐the‐art computational methods for linear acoustics are reviewed. The equations of linear acoustics are summarized and then transformed to the frequency domain for time‐harmonic waves governed by the Helmholtz equation. Two major current challenges in the field are specifically addressed: numerical dispersion errors that arise in the approximation of short unresolved waves, polluting resolved scales and requiring a large computational effort, and the effective treatment of unbounded domains by domain‐based methods. A discussion of the indefinite sesquilinear forms in the corresponding weak form are summarized. A priori error estimates, including both dispersion (phase error) and global pollution effects for moderate to large wave numbers in finite element methods, are discussed. Stabilized and other wave‐based discretization methods are reviewed. Domain‐based methods for modeling exterior domains are described including Dirichlet‐to‐Neumann (DtN) methods, absorbing boundary conditions, infinite elements, and the perfectly matched layer (PML). Efficient equation‐solving methods for the resulting complex‐symmetric (non‐Hermitian) matrix systems are discussed including parallel iterative methods and domain decomposition methods including the FETI‐H method. Numerical methods for direct solution of the acoustic wave equation in the time domain are reviewed.
Turbulence Closure Models for Computational Fluid Dynamics
Authors: Durbin Paul A. 
Published: January 2005

AbstractThe formulation of analytical turbulence closure models for use in computational fluid mechanics is described. The subject of this chapter is the types of models that are used to predict the statistically averaged flow field – commonly known as Reynolds‐averaged Navier–Stokes equations (RANS) modeling. A variety of models is reviewed: these include two‐equation, eddy viscosity transport, and second moment closures. How they are formulated is not a main theme; it enters the discussion but the models are presented largely at an operational level. Several issues related to numerical implementation are discussed. Relative merits of the various formulations are commented on.
CFD‐Based Nonlinear Computational Aeroelasticity
Authors: Farhat Charbel 
Published: January 2005

AbstractThis chapter overviews a three‐field formulation of nonlinear aeroelastic problems, where the fluid is modeled by the arbitrary Lagrangian–Eulerian (ALE) form of either the Euler or Navier–Stokes equations; the structure is represented by a detailed finite element model, and the fluid‐mesh is unstructured, dynamic, and constructed by a robust structure‐analogy–based method. It also discusses recent advances in the computational algorithms associated with this approach for modeling nonlinear fluid/structure interaction problems. These include CFD schemes that are formally second‐order time‐accurate on moving grids, energy‐transfer–conserving methods for discretizing transmission conditions across nonmatching fluid and structure discrete interfaces, and state‐of‐the‐art loosely coupled algorithms for solving efficiently coupled systems of fluid and structural equations arising from the discretization of real aircraft configurations. A taste of the capabilities of such algorithms is provided by reporting on their validation for an F‐16 fighter aircraft configuration in various subsonic, transonic, and supersonic airstreams, and at various load factors. The chapter concludes with a discussion of the feasibility and merit of the overviewed computational technology for accurately extracting the flutter envelopes of civilian and military aircraft, and a perspective on future research in CFD‐based nonlinear computational aeroelasticity.
The Use of Mixed Finite Element Methods for Viscoelastic Fluid Flow Analysis
Authors: Baaijens Frank P. T. , Hulsen Martien A. , Anderson Patrick D. 
Published: January 2005

AbstractThe numerical analysis of non‐Newtonian viscoelastic flows is a challenging task, and requires accurate, efficient, and robust computational methods. In this work, mixed finite element methods are used for that purpose. They are introduced within the context of closed‐form differential constitutive models. Their application to steady and time‐dependent viscoelastic flows and stability analysis is discussed. Application to model polymer melt flows is briefly addressed. These techniques can also be adapted to solve problems with models that cannot be written as closed‐form differential models. Two examples thereof are the deformation fields method for closed‐form constitutive equations and the Brownian configuration fields formulation for stochastic constitutive models.
Ship Hydrodynamics
Authors: Oñate Eugenio , García Julio , Idelsohn Sergio R. , Idelsohn Sergio R. 
Published: January 2005

AbstractThis chapter presents an overview of some computational methods for analysis of ship hydrodynamics problems. Attention is focused on the description of a stabilized finite element formulation derived via a finite calculus procedure. Both arbitrary Lagrangian–Eulerian (ALE) and fully Lagrangian forms are presented. Details of the treatment of the free‐surface waves and the interaction between the ship structure and the seawater are also given. Examples of application to a variety of ship hydrodynamics problems are shown.
Cluster kinetics of granular mixing
Authors: McCoy Benjamin J. , Madras Giridhar 
Published: January 2005

AbstractGranular mixing of identical particles that cluster together is a challenging and important engineering problem. Mixing requires the breakup of clusters, both by individual particle detachment and cluster fragmentation. We apply a population balance (distribution kinetics) approach to describe such size‐distributed cluster processes. Expressions for mixing effectiveness and segregation measures are derived and expressed in terms of the rate coefficients for reversible cluster distribution kinetics. Analytical and numerical moment solutions illustrate how the novel method is implemented and also provide some realistic results. The method allows straightforward derivation of experimentally observed long‐time power law or exponential asymptotic behavior of segregation metrics for various rate coefficient expressions. © 2005 American Institute of Chemical Engineers AIChE J, 51: 406–414, 2005
Autistic‐like behavior in CHARGE syndrome
Authors: Hartshorne Timothy S. , Grialou Tina L. , Parker Kellie R. 
Published: January 2005

AbstractChildren with CHARGE syndrome frequently exhibit moderate to severe behavior difficulties, and are often diagnosed with obsessive‐compulsive disorder, attention deficit disorder, Tourette syndrome, and autism. Hartshorne and Cypher (2004) surveyed parents of 100 children with CHARGE worldwide and confirmed the prevalence of behaviors that are associated with these disorders. They also found behaviors that could be described as typical of persons who are deafblind. The present study examined whether the autistic‐like behaviors of children with CHARGE are more similar to those of children who are deafblind, to those of children who are autistic or are unique to CHARGE. Surveys including the Autism Behavior Checklist (ABC) were mailed to families of 204 children with CHARGE, and 160 usable surveys were returned (78%). Total scores on the ABC for children with CHARGE were significantly different from the norms for those with autism, and those who were deafblind. However, the variance for CHARGE was larger than for the normative groups, and 27.5% of those with CHARGE could be classified as autistic. The pattern of subscale scores for those with CHARGE differed from the other normative groups. © 2005 Wiley‐Liss, Inc.
The epitaxial growth of gallium arsenide using triethylarsine
Authors: Maeda T , Hata M , Zempo Y , Fukuhara N , Matsuda Y , Sawara K 
Published: January 2005

AbstractThe thermal decomposition of triethylarsine (TEAs) has been studied. It decomposes at a lower temperature than arsine (AsH3). The decomposition proceeds via a radical process at a temperature above 700°C. Epitaxial growth using TEAs has been investigated. A gallium arsenide (GaAs) layer with good morphology was obtained, but the layer was found to contain a considerable amount of carbon impurity originating from TEAs. The use of TEAs with 10% AsH3 or with 20% ammonia (NH3) apparently improves the quality of GaAs layer. A possible scheme for reducing carbon incorporation is discussed.
The thermolysis of dicarbonylcyclopentadienyliron dimer: The formation of biferrocene
Authors: Wilkie Charles A , Huettl Brian 
Published: January 2005

AbstractThe thermolysis of dicarbonylcyclopentadienyliron dimer in a sealed tube at 300°C has been reported to produce ferrocene, carbon monoxide, carbon dioxide, cyclopentadiene and elemental iron. We observe in addition to these products the production of biferrocene and elemental carbon. Thermolysis of carbonylcyclopentadienyliron tetramer (produced from the dimer by thermolysis in refluxing xylene) produces ferrocene, iron and carbon monoxidre; no biferrocene, carbon dioxide or elemental carbon are produced. A scheme is proposed to account for these products.
Polarographic behaviour of some organotin(IV) compounds in dimethyl sulphoxide
Authors: Al‐Allaf Talal A K , Sulaiman Sadallah T , Hameed Yasser O 
Published: January 2005

AbstractThe differential pulse polarographic behaviour in dimethyl sulphoxide (DMSO) of 14 organotin(IV) compounds having the general formula R3SnX (R = Me, Ph; X− = NCS−, N3−, N3−, NO3−, OH−, NCO− and OAc−) and nBu3SnCl and nBu2SnCl2 has been studied. The peak potential was found to depend markedly on the organic group and to a lesser extent on the nature of the anion X. The phenyltin compounds were reduced at lower potentials than the corresponding methyltin compounds. The data obtained could be used for trace determination of these compounds. Linear calibration curves were obtained over the concentration range of 2.8 × 10−4 to 1.9 × 10−6 mol dm−3.
Butyltins in california river and lake marina waters
Authors: Stang Peter M , Goldberg Edward D 
Published: January 2005

AbstractButyltins were analyzed in waters from California river and lake marinas and were detected at the part per trillion (ppt) level in most locations. The tributyltin:dibutyltin (TBT/DBT) ratios in the fresh waters were similar to those in their saline counterparts indicating like rates of degradation in the two salinity regimes.
The preparation and structure of 1,4,5,6,7,7‐hexachloro‐2‐endo‐ferrocenylhydroxymethyl‐3‐endo‐hydroxymethyl‐5‐norbornene
Authors: Carty P , Grant J , Metcalfe E , Povey D C 
Published: January 2005

AbstractThe crystal structure of a novel ferrocene derivative with potential flame‐retardant/smoke‐suppressant activity, 1,4,5,6,7,7‐hexachloro‐2‐endo‐ferrocenyl‐hydroxymethyl‐3‐endo‐hydroxymethyl‐5‐norbornene, has been determined. Some of the carbon–carbon bonds within the chlorendic residue are unusually long, and there is no interaction between the hydroxyl groups and the iron atom. There is evidence of intramolecular hydrogen bonding between the two hydroxyl groups.
Organogallium compounds from metallic gallium through using metal‐vapor synthesis
Authors: Starowieski Kazimierz B , Klabunde Kenneth J 
Published: January 2005

AbstractThe first syntheses of organogallium compounds utilizing metallic gallium and alkyl halides (bromides and iodides) are presented. Metal‐vapor synthesis methods were used, and it is proposed that gallium atoms are the reactive species involved.Gallium also reacted with alkyl halides as fine particles in slurry form, but only when deposited in, or co‐deposited with, alkylaluminum compounds. Rationale for this finding is based on irregularity of the clusters due to incorporation of aluminum (or its compounds) and probably also on smaller particle sizes.
Tributyltin determination in marine sediments: A comparative study of methods
Authors: Astruc A , Lavigne R , Desauziers V , Pinel R , Astruc M 
Published: January 2005

AbstractTwo independent speciation methods have been applied to the determination of tributyltin (TBT) in marine sediments: (1) acetic acid leaching/hydride generation/cold trapping/GC/quartz furnace AA; and (2) toluene–tropolone extraction/HPLC/GFAA. TBT determines in a typically moderately polluted sediment (Porto Vecchio Bay, Corsica, France) are in very good agreement, as also are the determination of total recoverable tin by the first method and by a direct one using strong acid leaching followed by GFAA. These cross‐verifications lead one to conclude that both speciation methods are convenient and allow for valid determination of TBT in marine sediments, with no loss of TBT. Method‐induced modification of tin speciation has not been observed.
Insecticidal activity of some penta‐ and hexa‐coordinated heterocyclic β‐diketone derivatives of diorganotin(IV) against the stored product pest Rhizopertha (Coleoptera: Bostrichidae)
Authors: Saxena Prabhu N , Saxena Sanjiv 
Published: January 2005

AbstractSome new penta‐and hexa‐coordinated diorganotin complexes of heterocyclic β‐diketones having the general formula (n‐C4H9)2Sn(OPr1)2−n[RCOC:CON(C6H5) N:CCH3]n (where RCH3, C6H5 and p‐ClC6H4 and n = 1 and 2) have been synthesized and were screened for their insecticidal activity against Rhizopertha dominica (Fabricius), the lesser grain borer. The hexa‐coordinated complexes have been observed to be more active than the penta‐coordinated complexes.