bluuebunny/crossref_metadata_2025_split huggingface dataset:
p‐version of the generalized FEM using mesh‐based handbooks with applications to multiscale problems
Authors: Strouboulis Theofanis , Zhang Lin , Babuška Ivo 
Published: May 2004

AbstractIn this paper, we analyse the p‐convergence of a new version of the generalized finite element method (generalized FEM or GFEM) which employs mesh‐based handbook functions which are solutions of boundary value problems in domains extracted from vertex patches of the employed mesh and are pasted into the global approximation by the partition of unity method (PUM). We show that the p‐version of our GFEM is capable of achieving very high accuracy for multiscale problems which may be impossible to solve using the standard FEM. We analyse the effect of the main factors affecting the accuracy of the method namely: (a) The data and the buffer included in the handbook domains, and (b) The accuracy of the numerical construction of the handbook functions. We illustrate the robustness of the method by employing as model problem the Laplacian in a domain with a large number of closely spaced voids. Similar robustness can be expected for problems of heat‐conduction and elasticity set in domains with a large number of closely spaced voids, cracks, inclusions, etc. Copyright © 2004 John Wiley & Sons, Ltd.
Multi‐scale analysis and FE computation for the structure of composite materials with small periodic configuration under condition of coupled thermoelasticity
Authors: Feng Yong‐Ping , Cui Jun‐Zhi 
Published: May 2004

AbstractThe two‐scale asymptotic (TSA) expressions of the increment of temperature and the displacement for the structure of composite materials with small periodic configuration under coupled thermoelasticity condition are derived formally in this paper, especially, the two‐scale coupled relation between the increment of temperature and the displacements are set up. Then the approximate solutions and their error estimations are presented, and the multi‐scale finite element algorithm corresponding to TSA is described. Finally, simple numerical results evaluated by multi‐scale FE computation are shown. They demonstrate that the basic configuration and the increment of temperature strongly influence upon local strains and local stresses inside basic cell. Copyright © 2004 John Wiley & Sons, Ltd.
Adhesive element modelling and weighted static shape control of composite plates with piezoelectric actuator patches
Authors: Sun Dongchang , Tong Liyong 
Published: May 2004

AbstractA novel finite element model is presented for static and dynamic analysis of composite plates integrated with a laminated piezoelectric layer, a host laminated composite plate and an adhesive layer between them. A new adhesive element is developed which includes both peel and shear effects in the adhesive layer based on first‐order shear deformation plate theory. The thin adhesive layer between the piezoelectric layer and the host plate is modelled by assuming that it carries constant shear and peel strains throughout its thickness. In addition, a weighted static shape control scheme for finding the optimal voltage distribution for static shape control is given. By selecting different weighting matrices, a variety of items such as displacements, slopes, curvatures, strains and even generalized forces, can be included in finding the optimal actuating voltage for static shape control. The present model is validated by comparing with those results available in the literature. The numerical results show that the weighted linear least method can give a satisfactory voltage distribution to best match the desired shape. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison of regularization methods for solving the Cauchy problem associated with the Helmholtz equation
Authors: Marin L. , Elliott L. , Heggs P. J. , Ingham D. B. , Lesnic D. , Wen X. 
Published: May 2004

AbstractIn this paper, several boundary element regularization methods, such as iterative, conjugate gradient, Tikhonov regularization and singular value decomposition methods, for solving the Cauchy problem associated to the Helmholtz equation are developed and compared. Regularizing stopping criteria are developed and the convergence, as well as the stability, of the numerical methods proposed are analysed. The Cauchy problem for the Helmholtz equation can be regularized by various methods, such as the general regularization methods presented in this paper, but more accurate results are obtained by classical methods, such as the singular value decomposition and the Tikhonov regularization methods. Copyright © 2004 John Wiley & Sons, Ltd.
Procedures for approximate eigenproblem reanalysis of structures
Authors: Kirsch Uri , Bogomolni Michael 
Published: May 2004

AbstractIn vibration mode superposition analysis, the main computational effort is spent in the solution of the eigenproblem. In reanalysis procedures this solution must be repeated for each change in the design. It is shown in this study how the combined approximations method can be used to improve the efficiency of some common iterative procedures. These procedures can then be used for efficient eigenproblem reanalysis. Solution of the reduced eigenproblem by the combined approximations method is first demonstrated. Procedures based on inverse iteration, inverse iteration with shifts, and subspace iteration are then considered. Some numerical examples show that high accuracy is achieved for very large changes in the design. In cases where higher accuracy is required, additional terms of the approximations may be considered. Copyright © 2004 John Wiley & Sons, Ltd.
Bifurcation points and bifurcated branches by an asymptotic numerical method and Padé approximants
Authors: Boutyour E. H. , Zahrouni H. , Potier‐Ferry M. , Boudi M. 
Published: May 2004

AbstractThe aim of this work is to develop a reliable and fast algorithm to compute bifurcation points and bifurcated branches. It is based upon the asymptotic numerical method (ANM) and Padé approximants. The bifurcation point is detected by analysing the poles of Padé approximants or by evaluating, along the computed solution branch, a bifurcation indicator well adapted to ANM. Several examples are presented to assess the effectiveness of the proposed method, that emanate from buckling problems of thin elastic shells. Especially problems involving large rotations are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Studies of the strong coupling and weak coupling methods in FSI analysis
Authors: Zhang Qun , Hisada Toshiaki 
Published: May 2004

AbstractThe weak coupling methods in fluid–structure interaction analysis are newly classified into three types; the weak coupling method for solving structures with interfaces, the weak coupling method for solving fluids with interfaces, and the weak coupling method for solving both fluids and structures with interfaces. The consistent added matrices of these weak coupling methods are derived from the condensation of the strong coupling formulation. Some approximations for the consistent added matrices, which can avoid the matrix coupling, are proposed. The reasons for convergence difficulty in the weak coupling methods are clarified. A number of numerical results are presented to investigate the convergence properties and computational efficiency of these methods. Copyright © 2004 John Wiley & Sons, Ltd.
Truncation error and stability analysis of iterative and non‐iterative Thomas–Gladwell methods for first‐order non‐linear differential equations
Authors: Kavetski Dmitri , Binning Philip , Sloan Scott W. 
Published: May 2004

AbstractThe consistency and stability of a Thomas–Gladwell family of multistage time‐stepping schemes for the solution of first‐order non‐linear differential equations are examined. It is shown that the consistency and stability conditions are less stringent than those derived for second‐order governing equations. Second‐order accuracy is achieved by approximating the solution and its derivative at the same location within the time step. Useful flexibility is available in the evaluation of the non‐linear coefficients and is exploited to develop a new non‐iterative modification of the Thomas–Gladwell method that is second‐order accurate and unconditionally stable. A case study from applied hydrogeology using the non‐linear Richards equation confirms the analytic convergence assessment and demonstrates the efficiency of the non‐iterative formulation. Copyright © 2004 John Wiley & Sons, Ltd.
An adaptive least squares mixed finite element method for the stress‐displacement formulation of linear elasticity
Authors: Cai Zhiqiang , Korsawe Johannes , Starke Gerhard 
Published: May 2004

AbstractA least‐squares mixed finite element method for linear elasticity, based on a stress‐displacement formulation, is investigated in terms of computational efficiency. For the stress approximation quadratic Raviart‐Thomas elements are used and these are coupled with the quadratic nonconforming finite element spaces of Fortin and Soulie for approximating the displacement. The local evaluation of the least‐squares functional serves as an a posteriori error estimator to be used in an adaptive refinement algorithm. We present computational results for a benchmark test problem of planar elasticity including nearly incompressible material parameters in order to verify the effectiveness of our adaptive strategy. For comparison, conforming quadratic finite elements are also used for the displacement approximation showing convergence orders similar to the nonconforming case, which are, however, not independent of the Lamé parameters. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
High‐order numerical methods for one‐dimensional parabolic singularly perturbed problems with regular layers
Authors: Clavero C. , Gracia J. L. , Jorge J. C. 
Published: May 2004

AbstractIn this work we construct and analyze some finite difference schemes used to solve a class of time‐dependent one‐dimensional convection‐diffusion problems, which present only regular layers in their solution. We use the implicit Euler or the Crank‐Nicolson method to discretize the time variable and a HODIE finite difference scheme, defined on a piecewise uniform Shishkin mesh, to discretize the spatial variable. In both cases we prove that the numerical method is uniformly convergent with respect to the diffusion parameter, having order near two in space and order one or 3/2, depending on the method used, in time. We show some numerical examples which illustrate the theoretical results, in the case of using the Euler implicit method, and give better numerical behaviour than that predicted theoretically, showing order two in time and order N−2log2N in space, if the Crank‐Nicolson scheme is used to discretize the time variable. Finally, we construct a numerical algorithm by combining a third order A‐stable SDIRK with two stages and a third‐order HODIE difference scheme, showing its uniformly convergent behavior, reaching order three, up to a logarithmic factor. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Rhabdomyolysis with HMG‐CoA reductase inhibitors and gemfibrozil combination therapy
Authors: Chang Jennie T. , Staffa Judy A. , Parks Mary , Green Lanh 
Published: May 2004

AbstractContextElevated total cholesterol (total‐C) and low‐density lipoprotein cholesterol (LDL‐C) levels are established risk factors for cardiovascular disease (CVD). HMG‐CoA reductase inhibitors (statins) are effective cholesterol‐lowering drugs that are commonly prescribed to treat this condition. These drugs are often combined with another class of drugs, fibric acid derivatives, to lower both cholesterol and triglyceride levels. Rhabdomyolysis is a known, rare serious side effect of statin monotherapy and of statin‐fibrate combination therapy.ObjectiveTo examine Food and Drug Administration's (FDA's) postmarketing database for cases of rhabdomyolysis in relation to monotherapy and combination use and calculate reporting rates for this event.DesignDomestic cases of statin‐ and statin/gemfibrozil‐associated rhabdomyolysis were culled from FDA's database and reviewed. Rhabdomyolysis was defined by CPK ≥ 10 000 IU/L, myopathic signs and symptoms and clinical diagnosis of rhabdomyolysis. Reporting rates, consisting of number of reported cases/number of prescriptions for each drug, were then calculated to determine whether the reporting of rhabdomyolysis cases was commensurate with extent of use of each statin in the population.SettingCases were obtained from the FDA adverse event reporting system (AERS) database.PatientsNA.Main Outcome MeasuresNumber of rhabdomyolysis cases were evaluated, along with outcomes, such as renal failure, dialysis and death.ResultsOf 866 total reported cases, 482 (56%) were associated with monotherapy and 384 (44%) related to combination therapy. More than 80% of reported cases for each drug resulted in hospitalization for renal failure and dialysis. 80 patients expired from events related directly to rhabdomyolysis. Reporting rates for all statins, except for cerivastatin, were similar and much lower than 1 per 100 000 prescriptions. The cerivastatin‐reporting rate was much higher at 4.24/100 000 prescriptions.ConclusionsRhabdomyolysis is a rare, serious side effect of statin monotherapy and of statin‐fibrate combination therapy. Clinicians need to remain cognizant of this potential adverse event and discuss signs and symptoms of muscle toxicity with patients in order improve the benefits‐to‐risks of treating dyslipidemia with statins. Copyright © 2004 John Wiley & Sons, Ltd.
A proteomic approach to analyze salt‐responsive proteins in rice leaf sheath
Authors: Abbasi Fida Mohammad , Komatsu Setsuko 
Published: May 2004

AbstractTo examine the response of rice to salt stress, changes in protein expression were analyzed using a proteomic approach. To investigate dose‐ and time‐dependent responses, rice seedlings were exposed to 50, 100 and 150 mM NaCl for 6 to 48 h. Proteins were extracted from leaf sheath and separated by two‐dimensional polyacrylamide gel electrophoresis. Eight proteins showed 1‐ to 3‐fold up‐regulation in leaf sheath, in response to 50 mM NaCl for 24 h. Among these, three proteins were unidentified (LSY081, LSY262 and LSY363) while five proteins were identified as fructose bisphosphate aldolases, photosystem II (PSII) oxygen evolving complex protein, oxygen evolving enhancer protein 2 (OEE2) and superoxide dismutase (SOD). The maximum expression levels of seven proteins were at 24 h. Their expression declined after 48 h of 50 mM NaCl treatment. In contrast, SOD maintained its elevated expression throughout these conditions. The increased expression of proteins seen in the 50 mM NaCl treatment group was less pronounced in the groups receiving 100 or 150 mM NaCl for 24 h. The expression of SOD was a common response to cold, drought, salt and abscisic acid (ABA) stresses while the expression of LSY081, LSY363 and OEE2 was enhanced by salt and ABA stresses. LSY262 was expressed in leaf sheath and root, while fructose bisphosphate aldolases, PSII oxygen evolving complex protein and OEE2 were expressed in leaf sheath and leaf blade. LSY363 was expressed in leaf sheath but was below the level of detection in leaf blade and root. These results indicate that specific proteins expressed in specific regions of rice show a coordinated response to salt stress.
Copolymerization of allyl butyl ether with acrylates via controlled radical polymerization
Authors: Venkatesh Rajan , Vergouwen Frank , Klumperman Bert 
Published: May 2004

AbstractThe atom transfer radical polymerization (ATRP) and reversible addition–fragmentation chain transfer (RAFT) of acrylates (methyl acrylate and butyl acrylate) with allyl butyl ether (ABE) were investigated. Well‐defined copolymers containing almost 20 mol % ABE were obtained with ethyl‐2‐bromoisobutyrate as an initiator. Narrow molar mass distributions (MMDs; polydispersity index ≤ 1.3) were obtained from the ATRP experiments, and they suggested conventional ATRP behavior, with no peculiarities caused by the incorporation of ABE. The comparable free‐radical (co)polymerizations resulted in broad MMDs. Increasing the fraction of ABE in the monomer feed led to an increase in the level of incorporation of ABE in the copolymer, at the expense of the overall conversion. Similarly, RAFT copolymerizations with S,S′‐bis(α,α′‐dimethyl‐α″‐acetic acid)trithiocarbonate also resulted in excellent control of the polymerization with a significant incorporation of ABE within the copolymer chains. The formation of the copolymer was confirmed with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). From the obtained MALDI‐TOF MS spectra for the ATRP and RAFT systems, it was evident that several units of ABE were incorporated into the polymer chain. This was attributed to the rapidity of the cross‐propagation of ABE‐terminated polymeric radicals with acrylates. This further indicated that ABE was behaving as a comonomer and not simply as a chain‐transfer agent under the employed experimental conditions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3271–3284, 2004
Influence of carboxyl‐terminated (butadiene‐co‐acrylonitrile) loading on the mechanical and thermal properties of cured epoxy blends
Authors: Thomas Raju , Abraham Jacob , Thomas P Selvin , Thomas Sabu 
Published: May 2004

AbstractA mixture of epoxy with liquid nitrile rubber, carboxyl‐terminated (butadiene‐co‐acrylonitrile) (CTBN) was cured under various temperatures. The cured resin was a two‐phase system, where spherical rubber domains were dispersed in the matrix of epoxy. The morphology development during cure was investigated by scanning electron microscope (SEM). There was slight reduction in the glass transition temperature of the epoxy matrix (Tg) on the addition of CTBN. It was observed that, for a particular CTBN content, Tg was found to be unaffected by the cure temperature. Bimodal distribution of particles was noted by SEM analysis. The increase in the size of rubber domains with CTBN content is due probably to the coalescence of the rubber particles. The mechanical properties of the cured resin were thoroughly investigated. Although there was a slight reduction in tensile strength and young's modulus, appreciable improvements in impact strength, fracture energy, and fracture toughness were observed. Addition of nitrile rubber above 20 parts per hundred parts of resin (phr) made the epoxy network more flexible. The volume fraction of dispersed rubbery phase and interfacial area were increased with the addition of more CTBN. A two‐phase morphology was further established by dynamic mechanical analysis (DMA). © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2531–2544, 2004
Effect of crosslinking on intermolecular interactions in thermosetting blends of epoxy resin with poly(ethylene oxide)
Authors: Hu Lindi , Lü Han , Zheng Sixun 
Published: May 2004

AbstractThe miscibility and intermolecular‐specific interactions in thermosetting blends of epoxy resin (ER) with poly(ethylene oxide) (PEO) cured with various amounts of 1,3,5‐tridroxybenzene (THB) were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The glass‐transition behavior indicated that all the blends were miscible and had homogeneous amorphous phases; FTIR showed that there were the intermolecular hydrogen‐bonding interactions between crosslinked ER and PEO. However, both the glass‐transition behavior and infrared spectroscopy also indicated that the intermolecular interactions were significantly reduced by the formation of crosslinked structures, which was shown by comparing the experimental results of poly(hydroxyether of bisphenol A) (PH)/PEO and ER/PEO blends cured with various amounts of the curing agent. In ER/PEO blends the intermolecular hydrogen‐bonding interactions were much weaker than the self‐association of hydroxyls of ER, which was in marked contrast to the interactions in PH/PEO blends. In ER/PEO blends with various amounts of the curing agent, the intermolecular interactions between epoxy polymers and PEO were reduced with an increasing degree of crosslinking. The results were interpreted in terms of the effect of crosslinking on the intermolecular interactions, such as steric shielding, the screening effect, and chain connectivity resulting from the formation of the three‐dimensional crosslinked network, which could reduce the intermolecular hydrogen‐bonding interactions among hydroxyls of ER versus ether oxygen atoms of PEO. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2567–2575, 2004
Respiratory illness in children attending daycare
Authors: Dales Robert E. , Cakmak Sabit , Brand Kevin , Judek Stan 
Published: May 2004

AbstractDaycare attendance has been associated with an increased occurrence of respiratory illness, but little is known about which children are at particular risk. Our objectives were to determine the association between the incidence of respiratory illness and attendance in daycare, and to determine if the risk is modified by selected sociodemographic factors. Using a prospective study design, 185 newborns in Prince Edward Island, Canada, were recruited between January 1997–March 2000. They were followed for 2 years or until the end‐date of the study in September 2000. Information on daycare attendance and respiratory illness was collected twice monthly by telephone interviews of the parent. Comparing those who were ever in daycare more than 1 day per week (daycare group) to those who were not, the association between daycare and illness was stronger among children 15 months of age compared to those less than 3 months of age (P < 0.001), and stronger among those without siblings than those with siblings (P < 0.001). Among those not in daycare, family income was inversely related to the proportion of days with an illness episode: 9.8% (CI, 6.0, 13.6) if family income was <$30,000 vs. 5.2% (CI, 4.1, 6.3) if ≥$30,000 (P = 0.003). However, in the daycare group, income did not influence illness, with respective values of 14.6% (CI, 12.4, 16.8) vs. 13.2% (CI, 12.1, 14.3) (P = 0.21). In conclusion, younger children and those with siblings may be less susceptible to illness associated with daycare, and daycare attendance may negate a protective effect of higher income on respiratory illness. Pediatr Pulmonol. 2004; 38:64–69. © 2004 Wiley‐Liss, Inc.