bluuebunny/crossref_metadata_2025_split huggingface dataset:
γ‐Radiation‐Induced Graft Copolymerization of Ethyl Acrylate onto Hydroxypropyl Methylcellulose
Authors: Wang Lili , Xu Yongshen 
Published: August 2006

AbstractSummary: Graft copolymerization of EA onto water‐soluble HPMC was carried out using γ‐radiation using both simultaneous and preirradiation in an aqueous medium. The effects of radiation environment, radiation dose, monomer concentration, and reaction temperature on percentage of grafting (G) and grafting efficiency (GE) were investigated. For preirradiation, the observed values for G and GE were higher in air than in a nitrogen atmosphere. G and GE values are obviously higher for preirradiation; their maximum values were obtained for a radiation dose of 1.8 kGy. The grafting parameters increase for increasing monomer concentration up to 0.15 mol · L−1, where they reach their saturation values. In the case of preirradiation, the largest grafting parameters are obtained at 65 °C. The graft copolymers obtained were characterized by FTIR spectroscopy, TEM, SEM, and XRD methods. The method of irradiation significantly affects the mechanical properties of the grafted HPMC samples. Samples prepared by simultaneous irradiation show superior mechanical properties. In addition, the equilibrium humidity adsorption behaviors of the grafted copolymers were also studied, and the humidity resistance behavior of HPMC was enhanced through the grafting copolymerization.Transmission electron micrograph of the HPMC‐g‐PEA water dispersion.magnified imageTransmission electron micrograph of the HPMC‐g‐PEA water dispersion.
Effects of exercise and creatine on myosin heavy chain isoform composition in patients with Charcot–Marie–Tooth disease
Authors: Smith Cheryl A. , Chetlin Robert D. , Gutmann Laurie , Yeater Rachel A. , Alway Stephen E. 
Published: August 2006

AbstractIt is not known whether myosin heavy chain (MHC) content changes in response to exercise training or creatine supplementation in subjects with Charcot–Marie–Tooth disease (CMT). Based on previous data, we hypothesized that resistance exercise and creatine would increase the percentage of type I MHC composition in the vastus lateralis muscle and that myosin isoform changes would correlate with improved chair rise‐time in CMT subjects. To test this hypothesis, 18 CMT subjects were randomly assigned to either a placebo or creatine group. All subjects performed a 12‐week, home‐based, moderate‐intensity resistance training program. Chair rise‐time was measured before and after the training program. Muscle biopsies were obtained from the vastus lateralis before and after the 12‐week program. Gel electrophoresis showed a significant decrease (∼30%) in MHC type I in CMT subjects given creatine supplementation when compared with placebo. There was a nonsignificant increase in both MHC type IIa (∼23%) and MHC type IIx (∼7%) in CMT subjects given creatine. Reduced MHC type I content and increased MHC type IIa content correlated with faster chair rise‐times (i.e., improved muscle performance). The training‐induced change in MHC IIa content was inversely correlated with chair rise‐time in CMT subjects given creatine. When the two subject groups were combined, there was a linear, negative relationship between the change in MHC type IIa content and chair rise‐time after training and a positive relationship between the training‐induced change in MHC type I content and chair rise‐time. These data suggest that improved function (chair rise‐time) was associated with a lower level of MHC type I and increased MHC type IIa composition. Furthermore, the data are consistent with the hypothesis that creatine supplementation alters MHC composition in CMT patients undergoing resistance training and that MHC changes associated with creatine supplementation can improve muscle function. Muscle Nerve, 2006
Simultaneous price, location, and capacity decisions on a line of time‐sensitive customers
Authors: Dobson Gregory , Stavrulaki Euthemia 
Published: August 2006

AbstractConsider a monopolist who sells a single product to time‐sensitive customers located on a line segment. Customers send their orders to the nearest distribution facility, where the firm processes (customizes) these orders on a first‐come, first‐served basis before delivering them. We examine how the monopolist would locate its facilities, set their capacities, and price the product offered to maximize profits. We explicitly model customers' waiting costs due to both shipping lead times and queueing congestion delays and allow each customer to self‐select whether she orders or not, based on her reservation price. We first analyze the single‐facility problem and derive a number of interesting insights regarding the optimal solution. We show, for instance, that the optimal capacity relates to the square root of the customer volume and that the optimal price relates additively to the capacity and transportation delay costs. We also compare our solutions to a similar problem without congestion effects. We then utilize our single‐facility results to treat the multi‐facility problem. We characterize the optimal policy for serving a fixed interval of customers from multiple facilities when customers are uniformly distributed on a line. We also show how as the length of the customer interval increases, the optimal policy relates to the single‐facility problem of maximizing expected profit per unit distance. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Comparison of fully implicit and IMPES formulations for simulation of water injection in fractured and unfractured media
Authors: Monteagudo J. E. P. , Firoozabadi A. 
Published: August 2006

AbstractIn this work, we compare the fully implicit (FI) and implicit pressure‐explicit saturation (IMPES) formulations for the simulation of water injection in fractured media. The system of partial differential equations is discretized within the discrete‐fracture framework using a control‐volume method. A unique feature of the methodology is that there is no need for the computation of matrix–fracture transfer terms.The non‐linear system of equations resulting from the FI formulation is solved with state‐of‐the‐art Newton and tensor methods. Direct and Krylov iterative methods are employed to solve the system resulting from the Newton linearization. The performance of the FI and IMPES formulations is compared with numerical testing. Results show that the contrast between matrix and fracture properties affects the performance of both IMPES and FI formulations and that the tensor method outperforms all the Newton solvers for the near‐singular Jacobian matrix. Copyright © 2006 John Wiley & Sons, Ltd.
Allman's triangle, rotational DOF and partition of unity
Authors: Tian Rong , Yagawa Genki 
Published: August 2006

AbstractA simplification of the 1984 Allman triangle (one of historically most important elements with rotational dofs) is presented. It is found that this old element takes a typical form of the partition of unity approximation. The Allman's rotation presented in the partition of unity form offers merits and convenience in formulation and practical applications. The stiffness matrix of the 1984 Allman triangle, which is originally computed from the linear strain triangular element (the 6 nodes quadratic triangle), can be obtained instead in a cheaper way from that of the constant strain triangular element. The constraint of the rotational terms during essential boundary treatment, which remains equivocal and ambiguous, is understood to be mandatory. The partition of unity notion enables a straightforward extension of the Allman's rotational dof to meshfree approximations. In numerical examples, we discuss suppression of spurious zero‐energy modes and patch tests. Standard benchmarks are carried out to assess performance of the newly formulated triangle and a meshfree approximation with the rotational dofs. Copyright © 2006 John Wiley & Sons, Ltd.
A projection semi‐implicit scheme for the coupling of an elastic structure with an incompressible fluid
Authors: Fernández M. A. , Gerbeau J.‐F. , Grandmont C. 
Published: August 2006

AbstractWe address the numerical simulation of fluid–structure systems involving an incompressible viscous fluid. This issue is particularly difficult to face when the fluid added‐mass acting on the structure is strong, as it happens in hemodynamics for example. Indeed, several works have shown that, in such situations, implicit coupling seems to be necessary in order to avoid numerical instabilities. Although significant improvements have been achieved during the last years, solving implicit coupling often exhibits a prohibitive computational cost. In this work, we introduce a semi‐implicit coupling scheme which remains stable for a reasonable range of the discretization parameters. The first idea consists in treating implicitly the added‐mass effect, whereas the other contributions (geometrical non‐linearities, viscous and convective effects) are treated explicitly. The second idea, relies on the fact that this kind of explicit–implicit splitting can be naturally performed using a Chorin–Temam projection scheme in the fluid. We prove (conditional) stability of the scheme for a fully discrete formulation. Several numerical experiments point out the efficiency of the present scheme compared to several implicit approaches. Copyright © 2006 John Wiley & Sons, Ltd.
Adaptive finite element methodology for tumour angiogenesis modelling
Authors: Peterson J. W. , Carey G. F. , Knezevic D. J. , Murray B. T. 
Published: August 2006

AbstractIn this paper, we consider an adaptive finite element approach for reliable, efficient solution of a class of continuum models for tumour‐induced angiogenesis. The ideas are demonstrated using an established three equation reaction/transport model that simulates aspects of tumour‐induced angiogenesis in a deterministic manner. The weak variational formulation and finite element approximation scheme for the model are developed, and a statistical approach for concurrent adaptive mesh refinement and coarsening is described. The appropriate form of the model and solution dependence on choice of parameters are explored. Computational results are presented for 1D, 2D and 3D geometry models. The effectiveness of the open‐source, parallel adaptive software library (LibMesh) that is being developed in the CFDLab at the University of Texas is also demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.
An alternative approach for numerical solutions of the Navier–Stokes equations
Authors: Chantasiriwan S. 
Published: August 2006

AbstractConventional approaches for solving the Navier–Stokes equations of incompressible fluid dynamics are the primitive‐variable approach and the vorticity–velocity approach. In this paper, an alternative approach is presented. In this approach, pressure and one of the velocity components are eliminated from the governing equations. The result is one higher‐order partial differential equation with one unknown for two‐dimensional problems or two higher‐order partial differential equations with two unknowns for three‐dimensional problems. A meshless collocation method based on radial basis functions for solving the Navier–Stokes equations using this approach is presented. The proposed method is used to solve a two‐ and a three‐dimensional test problem of which exact solutions are known. It is found that, with appropriate values of the method parameters, solutions of satisfactory accuracy can be obtained. Copyright © 2006 John Wiley & Sons, Ltd.
Computational method of inverse elastostatics for anisotropic hyperelastic solids
Authors: Lu Jia , Zhou Xianlian , Raghavan Madhavan L. 
Published: August 2006

AbstractThe paper presents a computational method for predicting the initial geometry of a finitely deforming anisotropic elastic body from a given deformed state. The method is imperative for a class of problem in stress analysis, particularly in biomechanical applications. While the basic idea has been established elsewhere Comput. Methods Appl. Mech. Eng. 1996; 136:47–57; Int. J. Numer. Meth. Engng 1998; 43: 821–838), the implementation in general anisotropic solids is not a trivial exercise, but comes after a systematic development of Eulerian representations of constitutive equations. In this paper, we discuss the general representation in the context of fibrous hyperelastic solids, and provide explicit stress functions for some commonly used soft tissue models including the Fung model and the Holzapfel model. A three‐field mixed formulation is introduced to enforce quasi‐incompressibility constraints. The practical utility of this method is demonstrated using an example of aneurysm stress analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Optimal layout design of three‐dimensional geometrically non‐linear structures using the element connectivity parameterization method
Authors: Yoon Gil Ho , Joung Young Soo , Kim Yoon Young 
Published: August 2006

AbstractThe topology design optimization of ‘three‐dimensional geometrically‐non‐linear’ continuum structures is still difficult not only because of the size of the problem but also because of the unstable continuum finite elements that arise during the optimization. To overcome these difficulties, the element connectivity parameterization (ECP) method with two implementation formulations is proposed. In ECP, structural layouts are represented by inter‐element connectivity, which is controlled by the stiffness of element‐connecting zero‐length links. Depending on the link location, ECP may be classified as an external ECP (E‐ECP) or an internal ECP (I‐ECP). In this paper, I‐ECP is newly developed to substantially enhance computational efficiency. The main idea in I‐ECP is to reduce system matrix size by eliminating some internal degrees of freedom associated with the links at voxel level. As for ECP implementation with commercial software, E‐ECP, developed earlier for two‐dimensional problems, is easier to use even for three‐dimensional problems because it requires only numerical analysis results for design sensitivity calculation. The characteristics of the I‐ECP and E‐ECP methods are compared, and these methods are validated with numerical examples. Copyright © 2006 John Wiley & Sons, Ltd.
Eight‐node Reissner–Mindlin plate element based on boundary interpolation using Timoshenko beam function
Authors: Zhang Hexin , Kuang J. S. 
Published: August 2006

AbstractA new eight‐node Reissner–Mindlin plate element is developed with a special interpolation within the element. This special interpolation is an extension of the element boundary interpolation that employs Timoshenko beam function for the boundary segment interpolation. The element function can effectively capture the structural behaviours of thick plates and achieve high precision in the analysis of thick plates. Patch tests and numerical investigations are conducted. It can be seen that the proposed element successfully passes all the patch tests. The results of the numerical investigation show that the proposed element is free of the shear locking phenomenon and possesses a higher accuracy in the analyses, as compared to the earlier research in the literature. Copyright © 2006 John Wiley & Sons, Ltd.
Optimization control of bionics shell roofs subjected to snow skidding
Authors: Tesar Alexander , Melcer Jozef 
Published: August 2006

AbstractDynamic identification and optimization of bionics shell roofs subjected to the snow skidding is dealt with in present paper. The optimization control of structural geometry in order to induce the aimed snow skidding with reduction of dead weight snow loads is aimed. Theoretical, numerical and experimental in situ assessments based on wave approaches of the problem are presented. Structural application in situ on attractive shell roof made of laminated wood with optimization control suggested is presented. Copyright © 2006 John Wiley & Sons, Ltd.
A sinh transformation for evaluating two‐dimensional nearly singular boundary element integrals
Authors: Johnston Barbara M. , Johnston Peter R. , Elliott David 
Published: August 2006

AbstractA new transformation technique is introduced for evaluating the two‐dimensional nearly singular integrals, which arise in the solution of Laplace's equation in three dimensions, using the boundary element method, when the source point is very close to the element of integration. The integrals are evaluated using (in a product fashion) a transformation which has recently been used to evaluate one‐dimensional near singular integrals. This sinh transformation method automatically takes into account the position of the projection of the source point onto the element and also the distance b between the source point and the element. The method is straightforward to implement and, when it is compared with a number of existing techniques for evaluating two‐dimensional near singular integrals, it is found that the sinh method is superior to the existing methods considered, both for potential integrals across the full range of b values considered (0<b⩽10), and for flux integrals where b>0.01. For smaller values of b, the use of the Lmethod is recommended for flux integrals. Copyright © 2006 John Wiley & Sons, Ltd.
Morphology based domain partitioning of multi‐phase materials: a preprocessor for multi‐scale modelling
Authors: Valiveti D. M. , Ghosh Somnath 
Published: August 2006

AbstractThis paper develops a microstructural morphology‐based domain partitioning method (MDP) as a comprehensive pre‐processor for multi‐scale simulation of heterogeneous multi‐phase materials. The MDP method systematically creates a multi‐scale image simulation–characterization methodology to enable domain partitioning that can delineate homogenizable regions from those where explicit representation of phases is necessary for analysis. The methods are strictly based on geometric features of the material morphology and do not use any mechanical response functions. The first step in this development simulates high‐resolution microstructural information from low resolution images of the domain and only a limited high resolution micrographs from optical or scanning electron microscopy. The second step uses quantitative characterization of these high resolution images with, e.g. phase distribution functions, to create effective metrics that can relate microstructural features to the material's physical behaviour. The third step invokes domain partitioning to demarcate regions corresponding to different length scales in a concurrent multi‐scale model. Partitioning criteria are defined in terms of descriptors of microstructural characteristics and these are used to adaptively create multi‐level domain partitions. The method developed is tested on a micrograph of a cast aluminium alloy A356. Copyright © 2006 John Wiley & Sons, Ltd.
Measurement of critical concentration for mesophase formation of chitosan derivatives in both aqueous and organic solutions
Authors: Dong Yan‐ming , Mao Wei , Wang Hui‐wu , Zhao Ya‐qing , Li Xiao‐jian , Bi Dan‐xia , Yang Liu‐lin , Ge Qiang , Fang Xueming 
Published: August 2006

AbstractA novel chitosan derivative, acryloyl chitosan (AcCs), and two N‐maleoyl chitosans, MaCs‐1 and MaCs‐2, with different degrees of substitution were synthesized using completely deacetylated chitosan as raw material under different reaction conditions. AcCs is an amphiphilic chitosan derivative, but MaCs‐1 and MaCs‐2 are soluble in water and organic solvents respectively. The concentrated solutions of AcCs, MaCs‐1 and MaCs‐2 all demonstrated mesophases and were investigated using polarizing optical microscopy (POM). Circular dichroism (CD) was also employed for determining the critical concentration for mesophase formation. A broad peak in the visible light region of CD spectra had its origin in the appearance of the mesophase, and arose from the selective reflection of cholesteric helix pitches. The results of CD measurements agreed with those of POM. The critical concentration values for aqueous solutions were much lower than those for organic solutions, which was explained by the strong interactions between the chitosan derivatives and water. Copyright © 2006 Society of Chemical Industry
Surface activity and solubilization of a novel series of functional polyurethane surfactants
Authors: Dong Yang , Jin Yong , Wei Deqing 
Published: August 2006

AbstractFunctional polyurethane surfactants (di‐block and tri‐block) were synthesized by addition polymerization of 2,4‐toluenediisocyanate with poly(propylene oxide) and monoallyl‐end‐capped poly(ethylene oxide). The chemical structure of the polyurethane surfactants was confirmed by Fourier transform infrared and 1H NMR spectroscopy. These polymeric surfactants were found to have excellent surface activity. The lowest surface tension of polyurethane surfactant aqueous solutions could be reduced to 37.6 mN m−1. All the polyurethane surfactants synthesized had low critical micelle concentrations and could reduce the surface tension even at very low concentration levels (10−6–10−5 mol L−1). The solubilization of toluene in micelles of the synthesized polyurethane surfactants was studied using UV‐visible spectroscopy, and the results showed that they all exhibited good solubilization capacity. Possible solubilization positions of toluene in the micelles are conjectured. Copyright © 2006 Society of Chemical Industry
Decontamination of Surfaces by Low Pressure Plasma Discharges
Authors: Rossi François , Kylián Ondřej , Hasiwa Marina 
Published: August 2006

AbstractSummary: Non‐equilibrium discharges in molecular gases and their mixtures have been extensively studied due to their applicability in different areas of surface treatment, cleaning and functionalization. In this paper, the feasibility of the use of low pressure discharges for sterilization and decontamination, i.e., a topic that has attracted great attention recently, is demonstrated and discussed using examples of bacterial spore sterilization and depyrogenation of bacterial endotoxins, as well as the elimination of protein films.Image of spores used for sterilization, showing heavy stacking.magnified imageImage of spores used for sterilization, showing heavy stacking.
Metallic TiO2
Authors: Sheppard L. R. , Bak T. , Nowotny J. 
Published: August 2006

AbstractThe present work reports the discovery of the effect of metallic‐type conduction for Nb‐doped TiO2 (0.65 at% Nb). This effect was attested by measurements of electrical conductivity at elevated temperatures (973–1223 K) in the gas phase of controlled oxygen activities. It is shown that the temperature coefficient of the mobility of electrons in reduced conditions is negative. This finding paves the way for the development of high‐efficiency photoelectrodes for photoelectrochemical hydrogen generation from water using solar energy with substantially reduced internal energy losses for charge transport. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)