bluuebunny/crossref_metadata_2025_split huggingface dataset:
Finite elements with penalties in nonlinear elasticity
Authors: Malkus David S. 
Published: October 2005

AbstractThis paper describes the use of a penalty method to enforce the constraint of incompressibility in nonlinear elasticity. As an example, a problem involving the use of the Newton–Raphson method in conjunction with incremental loading and a successive mesh refinement scheme is presented. It is shown that during the incremental loading phase and the Newton–Raphson refinement on a fixed mesh, all tangent stiffness matrices are positive definite for the chosen energy density and load increment. But when the mesh is refined and the solution is interpolated as a starting value on the new mesh, the tangent stiffness matrix is indefinite. A theoretical analysis of the associated mixed method and a new equivalence theorem are seen to lead to a way to retain positive definiteness. The key is the use of an equivalent tangent stiffness matrix which is the reduced Hessian matrix. The numerical example shows that both positive definiteness and the quadratic convergence rate of the Newton–Raphson method are obtained.
Galerkin and collocation‐Galerkin methods with superconvergence and optimal fluxes
Authors: Carey G. F. , Humphrey D. , Wheeler M. F. 
Published: October 2005

AbstractFinite element methods are formulated and investigated for the effectiveness factor problem for heat and mass transfer with chemical reactions in catalyst pellet models. A Galerkin finite element method is compared with a previous C1 collocation method7. A scheme that is conceptually intermediate between these two methods and accordingly has been termed collocation‐Galerkin is formulated and numerical experiments considered. Of particular interest here are superconvergence results at the Gauss and Jacobi points, respectively. Numerical studies of superconvergence in the presence of a nonlinear reaction‐rate term are presented. An integral formula is devised and used to compute the flux at the pellet surface to optimal accuracy. Numerical experiments are conducted to demonstrate the improvement in computed fluxes.
Stress evaluation algorithms for rate constitutive equations in finite deformation analysis
Authors: Lo S. H. 
Published: October 2005

AbstractThe stress integration algorithm for hypoelastic constitutive equations proposed by Pinsky et al.3 is extended for the treatment of finite deformation elastoplastic constitutive relations. Another approach based on the polar decomposition of the deformation gradient tensor F = R · U is also introduced. Numerical examples and a discussion on these two approaches are given.
A hybrid strain finite element for plates and shells
Authors: Bergmann V. L. , Mukherjee S. 
Published: October 2005

AbstractThis paper describes a new hybrid strain finite element for geometrically linear analysis of plates and shells. The formulation for materially linear problems is based on a mixed variational principle having strain and displacement rates as independently varied fields. To facilitate extension to materially non‐linear analysis, the variational principle is used in rate form and the plane stress assumption is not imposed a priori in the formulation. When desired, the plane stress assumption is imposed in a manner similar to imposition of fixed boundary conditions. The element geometry is based on a nine‐noded quadrilateral with biquadratic interpolation of the displacement field. The strain field is based on a bilinear interpolation with additional non‐linear terms, chosen on the basis of eigenvalue analysis. The element passes the required patch tests, does not display either membrane or shear locking effects, and is free of communicable spurious modes. Numerical results are presented for elastic analyses of several standard plate and shell test problems.
A hybrid optimal synthesis method for truss structures considering shape, material and sizing variables
Authors: Ohkubo Sadaji , Asai Kazuhiro 
Published: October 2005

AbstractA generalized hybrid optimal synthesis method is developed for truss structures in which the design variables are the co‐ordinates of the panel points, cross‐sectional areas and discrete material kinds of member elements. The primary design problem is formulated in terms of the shape, material and sizing variables and approximated to a sequence of convex and separable subproblems by using mixed direct/reciprocal design variables. Each subproblem is solved by a dual method in which the continuous shape and sizing variables are optimized by a Newton‐type algorithm and the discrete material and continuous sizing variables are improved by a discrete sensitivity analysis. Using the proposed method, discrete material kinds, shape and sizing variables can be systematically improved to obtain an optimum solution. The rigourness, reliability and efficiency of the method are demonstrated by applying it to the minimum cost design of trusses subjected to stress and displacement constraints.
An adaptive finite element procedure for 2D dynamic transient analysis using direct integration
Authors: Zeng L. F. , Wiberg N.‐E. , Bernspång L. 
Published: October 2005

AbstractAn adaptive h‐version finite element procedure is presented for a 2D elastodynamic transient analysis using direct integration. The procedure modifies the spatial discretization, i.e. the mesh, in time so that the spatial discretization error can be controlled in each time instant. We analyse an a priori error estimate for the total energy which shows that an a posteriori error estimate developed by Zienkiewicz and Zhu for linear elastostatics can reasonably be extended to dynamic transient analysis. For the time integration, both explicit and implicit time integration schemes can be coupled with the procedure. However, the study in this paper is confined to the use of the Newmark scheme. Numerical examples are used to study the performance of the error estimate and to illustrate the adaptive procedure. Obtained numerical results indicate that: (i) the extension of the Zienkiewicz–Zhu estimate to dynamic transient analysis is useful; (ii) the presented adaptive procedure can, in an efficient way, provide a finite element solution with a user‐controlled accuracy.
A note on the grid movement induced by MFE
Authors: Zegeling P. A. , Blom J. G. 
Published: October 2005

AbstractMoving‐grid methods in one space dimension have become popular for solving several kinds of parabolic and hyperbolic partial differential equations (PDEs) involving fine scale structures such as steep moving fronts and emerging steep layers, pulses, shocks, etc. In two space dimensions, however, application of moving‐grid methods is less trivial than in 1D. For some methods, e.g. those based on equidistributing principles, it is not even clear how to extend the underlying grid selection procedure to 2D. The moving‐finite‐element (MFE) method does not suffer from this drawback; its mathematical extension to 2D is trivial. However, because of the intrinsic coupling between the discretization of the PDE and the grid selection, the application of MFE, as for any other method, is not without difficulties. In this paper we describe the node movement induced by MFE for various PDEs and we indicate some problems concerning the grid structure that can result from this movement.
Viscous heating in forced convective heat transfer across a circular cylinder at low reynolds number
Authors: Sunden Bengt 
Published: October 2005

AbstractThe influence of viscous heating on forced convective heat transfer from a circular cylinder in cross flow is investigated numerically. The Reynolds number is in the range of 5–40 and the Prandtl number is 0.72, corresponding to air. The Navier–Stokes equations and the continuity equations are solved in two dimensions using the streamfunction‐vorticity formulation. In the energy equation the dissipation of mechanical energy into thermal energy is taken into account. All equations are cast into a non‐dimensional form. The numerical solution procedure is based on second‐order finite difference approximations and an implicit formulation is employed. The far field boundary conditions of the flow field are satisfied by matching to asymptotic solutions. The resulting algebraic equations are solved by an iterative relaxation technique. In particular, temperature distributions for an adiabatic wall boundary condition are presented.
A finite element approach to kinetic energy discretization of deformable bodies in quasi‐rigid motion
Authors: Lucibello P. , D'Ambrogio W. 
Published: October 2005

AbstractIn this paper a finite element technique for the discretization of kinetic energy of bodies subjected to large rigid motion and small deformation (which we refer to as quasi‐rigid motion) is presented. First, on the basis of a separation between the rigid displacement and the deformation, the relevant kinematic relationships are derived. A standard assumed‐mode approach is used to describe the deformation displacement field by a linear combination of known functions. Then, the computation of the kinetic energy leads to the definition of a set of tensors, which are configuration‐independent (like the mass matrix in a linear setting) and fully characterize the body non‐linear dynamic behaviour introduced by large rotation. A computer code has been developed, in order to extend an existing FE package, for the computation of these tensors. Details of the technique, including storage requirements and suggestions for model reduction, are given. Finally, two examples are presented: (i) the result of the computation of one of the introduced tensors; (ii) the development of the non‐linear model of a rotating beam.
A possible case of surgical treatment of cranial blunt force injury from medieval England
Authors: Mays S. A. 
Published: October 2005

AbstractA possible example of surgical treatment of depressed fracture of the cranium is presented. The individual involved is a medieval peasant from Wharram Percy. The burial dates from the 10th–11th century AD. The surgery appears to have involved the use of trepanation by the scraping technique. This case pre‐dates the first documentary descriptions in the medieval West of similar operations to treat cranial fracture, and shows that access to complex surgical treatment was not invariably the preserve of the wealthy in medieval England. Copyright © 2005 John Wiley & Sons, Ltd.
Diameter of the human internal acoustic meatus and sex determination
Authors: Lynnerup N. , Schulz M. , Madelung A. , Graw M. 
Published: October 2005

AbstractWe report the results of testing the diameter of the internal opening of the acoustic canal in the petrous part of the temporal bone for sex determination of skeletal remains. The method involves measuring the diameter using a suite of ordinary drills. The method is very simple and has the great advantage of utilising one of the sturdiest bone elements of the human skeleton. The method may be especially useful for the analyses of very fragmented skeletal remains or cremated bones, where the petrous bone may still be readily recognisable. The method was tested using a forensic sample of 113 left petrous bones with known sex. Intra‐ and inter‐observer testing was also performed. We found a statistically significant difference in diameter between males and females (means: males: 3.7 mm; females: 3.4 mm; P < 0.009). However, the low predictive value (70%) for correct sexing using two sectioning points ( < 3.0 mm = female; >3.5 mm = male) was disappointing. No additional accuracy was gained by employing both left and right petrous bones (a bilateral sample of 60 petrous bones was also tested), although left and right side diameter is highly correlated (R = 0.778; P = 0.0001). Copyright © 2005 John Wiley & Sons, Ltd.
Rapid and accurate determination of MYCN copy number and 1p deletion in neuroblastoma by quantitative PCR
Authors: Anderson John , Gibson Sian , Williamson Dan , Rampling Dyanne , Austin Catherine , Shipley Janet , Sebire Neil , Brock Penelope 
Published: October 2005

AbstractMYCN amplification and 1p36 deletion are adverse prognostic factors in neuroblastoma, and rapid accurate determination of MYCN amplification is essential for risk stratification. MYCN copy number and 1p36 deletion status were determined by fluorescence in situ hybridization (FISH) and real time PCR in a diagnostic pathology laboratory setting on 35 consecutive patients with neuroblastoma. The PCR technique was technically successful in all cases and results were generally available within 24 hr of biospy. There was no discordance between FISH and PCR results. Real time PCR is a reliable, accurate, and simple technique that can be applied to small neuroblastoma biopsies allowing rapid diagnosis. © 2005 Wiley‐Liss, Inc.
Proceedings of the tumor board of St. Jude Children's Research Hospital, Memphis, Tennessee: Gestational choriocarcinoma
Authors: Weiss Aaron , Khoury Joseph D. , Kaste Sue C. , Spunt Sheri L. 
Published: October 2005

AbstractThis paper describes a recent tumor board presentation conducted at our institution involving an adolescent with gestational choriocarcinoma. Despite its rarity in pediatrics, gestational choriocarcinoma offers unique diagnostic, treatment and off‐therapy considerations in adolescent patients who have become pregnant. Key features and findings of the case as well as important management issues will be discussed. Pediatr Blood Cancer 2006; 47:640–646. © 2005 Wiley‐Liss, Inc.
Urinary hepcidin in congenital chronic anemias
Authors: Kearney Susan L. , Nemeth Elizabeta , Neufeld Ellis J. , Thapa Dharma , Ganz Tomas , Weinstein David A. , Cunningham Melody J. 
Published: October 2005

AbstractBackgroundHepcidin, a regulator for iron homeostasis, is induced by inflammation and iron burden and suppressed by anemia and hypoxia. This study was conducted to determine the hepcidin levels in patients with congenital chronic anemias.ProcedureForty‐nine subjects with anemia, varying degrees of erythropoiesis and iron burden were recruited. Eight children with immune thrombocytopenia were included as approximate age‐matched controls. Routine hematologic labs and urinary hepcidin (uhepcidin) levels were assessed. For thalassemia major (TM) patients, uhepcidin was obtained pre‐ and post‐transfusion.ResultsIn TM, uhepcidin levels increased significantly after transfusion, demonstrated wide variance, and the median did not significantly differ from controls or thalassemia intermedia (TI). In both thalassemia syndromes, the hepcidin to ferritin ratio, a marker of the appropriateness of hepcidin expression relative to the degree of iron burden, was low compared to controls. In TI and sickle cell anemia (SCA), median uhepcidin was low compared to controls, P = 0.013 and <0.001, respectively. In thalassemia subjects, uhepcidin levels were positively associated with ferritin. In subjects with SCA, uhepcidin demonstrated a negative correlation with reticulocyte count.ConclusionsThis study examines hepcidin levels in congenital anemias. In SCA, hepcidin was suppressed and inversely associated with erythropoietic drive. In thalassemic syndromes, hepcidin was suppressed relative to the degree of iron burden. Transfusion led to increased uhepcidin. In thalassemia, the relative influence of known hepcidin modifiers was more difficult to assess. In thalassemic syndromes where iron overload and anemia have opposing effects, the increased erythropoietic drive may positively influence hepcidin production. Pediatr Blood Cancer 2007;48:57–63. © 2005 Wiley‐Liss, Inc.
Synthesis and electrochemical and electroluminescent properties of N‐phenylcarbazole‐substituted poly(p‐phenylenevinylene)
Authors: Liang Fushun , Kurata Takashi , Nishide Hiroyuki , Kido Junji 
Published: October 2005

AbstractAn N‐phenylcarbazole‐containing poly(p‐phenylenevinylene) (PPV), poly[(2‐(4′‐carbazol‐9‐yl‐phenyl)‐5‐octyloxy‐1,4‐phenylenevinylene)‐alt‐(2‐(2′‐ethylhexyloxy)‐5‐methoxy‐1,4‐phenylenevinylene)] (Cz‐PPV), was synthesized, and its optical, electrochemical, and electroluminescent properties were studied. The molecular structures of the key intermediates, the carbazole‐containing boronic ester and the dialdehyde monomer, were crystallographically characterized. The polymer was soluble in common organic solvents and exhibited good thermal stability with a 5% weight loss at temperatures above 420 °C in nitrogen. A cyclic voltammogram showed the oxidation peak potentials of both the pendant carbazole group and the PPV main chain, indicating that the hole‐injection ability of the polymer would be improved by the introduction of the carbazole‐functional group. A single‐layer light‐emitting diode (LED) with a simple configuration of indium tin oxide (ITO)/Cz‐PPV (80 nm)/Ca/Al exhibited a bright yellow emission with a brightness of 1560 cd/m2 at a bias of 11 V and a current density of 565 mA/cm2. A double‐layer LED device with the configuration of ITO/poly(3,4‐ethylenedioxy‐2,5‐thiophene):poly (styrenesulfonic acid) (60 nm)/Cz‐PPV (80 nm)/Ca/Al gave a low turn‐on voltage at 3 V and a maximum brightness of 6600 cd/m2 at a bias of 8 V. The maximum electroluminescent efficiency corresponding to the double‐layer device was 1.15 cd/A, 0.42 lm/W, and 0.5%. The desired electroluminescence results demonstrated that the incorporation of hole‐transporting functional groups into the PPVs was effective for enhancing the electroluminescent performance. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5765–5773, 2005
Synthesis of core‐shell structured carboxylated microparticles with a straightforward procedure and their evaluation as a polymer support
Authors: Albertsson Ann‐Christine , David Geta , Strandberg Clara , Bilba Doina , Paduraru Carmen 
Published: October 2005

AbstractPoly(trimethylolpropane trimethacrylate) microspheres with a narrow size distribution were obtained by precipitation polymerization. They were subsequently modified by surface grafting with acrylic acid in a polar ethanol–water reaction medium, without stabilizer, yielding core‐shell particles with diameters in the micrometer range. The resulting polymeric material was characterized by SEM and potentiometric titration, FTIR spectroscopy, and thermal analysis. It was shown that the particle characteristics (size, size distribution, and functionality) obtained by this straightforward procedure can be controlled by modifying the synthesis parameters (monomer concentration, agitation rate, and temperature). The high functionality, the chemical and physico‐mechanical stability, as well as the possibility to control the performances of the resulting polymeric materials by synthesis allow its applications in various areas. Envisaging separation and catalysis domains, Cu(II), Cd(II), and Cr(III) uptake capacity from aqueous solutions was investigated under noncompetitive conditions as a function of synthesized particle functionality, time, and pH range. It was also found that the addition of the carboxylated microparticles to polyethylene stabilized with α‐tocopherol improved the thermo‐oxidative behaviour of the polymeric material. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5889–5898, 2005
Radical polymeric photoinitiators bearing side‐chain camphorquinone moieties linked to the main chain through a flexible spacer
Authors: Angiolini Luigi , Caretti Daniele , Rossetti Stefano , Salatelli Elisabetta , Scoponi Marco 
Published: October 2005

AbstractNew polymeric photoinitiators bearing the side‐chain camphorquinone moiety spaced from the backbone by a long and flexible connection have been prepared and tested in the photocuring of acrylic monomers upon irradation with visible light in the presence of tertiary amine coinitiator. The results indicate that the photoinitiating activity of the polymeric initiators may be comparable to the related combination of low molecular weight derivatives when the camphorquinone component has a polymeric structure, and depends on the chemical structure of both the components of the initiator/coinitiator pair. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5879–5888, 2005
Preparation and properties of high performance epoxy–silsesquioxane hybrid resins prepared using a maleimide–alkoxysilane compound as a modifier
Authors: Liu Ying‐Ling , Chang Gung‐Pei , Wu Chuan‐Shao , Chiu Yie‐Shun 
Published: October 2005

AbstractAn alkoxysilane compound possessing maleimide moiety (MSM) was prepared from N‐(4‐hydroxyphenyl)maleimide and 3‐glycidoxypropyltrimethoxysilane and was used as a modifier of epoxy resins. In situ curing epoxy resins with MSM resulted in epoxy resins with good homogeneity. Just 5–10 wt % of MSM is sufficient to yield high glass transition temperature (165 °C), good thermal stability above 360 °C, and high flame retardancy (LOI = 30) to bisphenol‐A‐based epoxy resins. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5787–5798, 2005
Genesis of the CSIRO polymer group and the discovery and significance of nitroxide‐mediated living radical polymerization
Authors: Solomon David H. 
Published: October 2005

AbstractThe background to the formation of the Commonwealth Scientific and Industrial Research Organization (CSIRO) polymer group is discussed. In particular, the challenges of working with high‐conversion polymerization, as found in commercial systems, and the need to explain variations in polymer properties led to important advances in the theory of radical polymerization and control over both the initiation and termination steps. Studies on the fate of the macromonomer, formed in termination by disproportionation, led to an early form of addition/fragmentation now known as reversible addition–fragmentation chain transfer, whereas detailed studies on initiation pathways using nitroxide trapping led to nitroxide‐mediated living radical polymerization. These studies contributed to the renaissance in free‐radical polymerization studies. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5748–5764, 2005
Thermally responsive complex polymer networks containing Fe3O4 nanoparticles: Composition/morphology/property relationship
Authors: Lin Chia‐Lung , Chiu Wen‐Yen 
Published: October 2005

AbstractIn this research, the synthesis and properties of thermally responsive complex polymer networks containing Fe3O4 nanoparticles were studied. First, a stable ferrofluid containing Fe3O4 nanoparticles was synthesized via a coprecipitation method in the presence of a poly(acrylic acid) oligomer. This stable ferrofluid could mix well with water‐soluble monomers by the adjustment of its pH value. Second, a thermally responsive copolymer was synthesized in the presence of the ferrofluid containing Fe3O4 nanoparticles to obtain the complex polymer networks. By the adjustment of the pH value, the ferrofluid could remain stable in the polymerization system, in which N‐isopropylacrylamide (NIPAAm) and methacrylic acid (MAA) were used as comonomers to provide thermoresponsive properties and acid groups and ammonium persulfate and sodium metabisulfite were used as the redox initiator system. Several variables, such as the molar ratio of MAA to NIPAAm, the concentrations of the monomers and crosslinking agent, the addition of an ammonium solution, and the content of the ferrofluid, were studied in this polymerization. Their effects on the morphology, structure, polymerization rate, and thermal properties of the complex polymer networks were discussed. The swelling and thermoresponsive behaviors of the complex polymer networks containing Fe3O4 nanoparticles were also studied, and the composition–morphology–property relationship was established. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5923–5934, 2005