bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multifunctional Porous Poly(vinylidene fluoride)‐graft‐Poly(butyl methacrylate) with Good Li+ Ion Conductivity
Authors: Samanta Sanjoy , Chatterjee Dhruba P. , Layek Rama K. , Nandi Arun K. 
Published: October 2010

AbstractPnBMA is grafted on PVDF using ATRP in NMP solution at 90 °C and characterized by means of 1D and 2D NMR. 19F NMR spectra clearly reveal that the attack occurs on the head‐head >CF2 groups. Cast PB films show a honeycomb‐patterned porous microstructure, and the “breath‐figure” model is used to explain pore formation. FT‐IR spectra suggest a supramolecular interaction between >CO groups of PnBMA and >CF2 groups of PVDF. Storage modulus, loss modulus and stress at break decrease with graft conversion, but the strain at break increases significantly. The toughness of the copolymers also increases dramatically (882%). The porous materials can be applied as solid‐state electrolytes (Li+‐doped) with good ionic conductivity (10−5 S · cm−1). magnified image
Synthesis, Crystallization, and Enzymatic Degradation of the Biodegradable Polyester Poly(ethylene azelate)
Authors: Papageorgiou George Z. , Bikiaris Dimitrios N. , Achilias Dimitris S. , Karagiannidis Nikitas 
Published: October 2010

AbstractPoly(ethylene azelate) (PEAz) was synthesized and its melting behavior was studied with DSC and Step Scan DSC. The equilibrium melting point of PEAz was found 62 °C and the heat of fusion of 100% crystalline polymer was estimated at 160 J · g−1. Polarized light microscopy showed mixed birefringence. From isothermal crystallization DSC study, after self‐nucleation, crystallization rates were estimated. The Lauritzen–Hoffman plots showed crystallization regime I to II and II to III transition at 34 and 19 °C respectively. Non‐isothermal crystallization was studied. The activation energy was calculated applying the isoconversional method of Friedman. Chemical hydrolysis of PEAz was very slow, while enzymatic hydrolysis showed comparable rates with PCL. magnified image
A Highly Efficient Polymerizable Photoinitiator Comprising Benzophenone, Thio Moieties, and N‐Arylmaleimide
Authors: Wei Jun , Wang Baozong 
Published: October 2010

AbstractA novel, highly efficient, polymerizable, thio‐containing photoinitiator, 4‐maleimido‐4'‐thiophenylbenzophenone (MTBP), was synthesized by directly introducing maleimide to benzophenone moieties. Three polymerizable photoinitiators with different location or number of maleimide substituents, together with the bare benzophenone, were chosen to evaluate the photoefficiency of MTBP. Photopolymerization studies indicate that polymerizable photoinitiator with single maleimide substituent directly linking to benzophenone moieties is more efficient for photopolymerization of vinyl monomers than those with indirect or double maleimide substituents. As for the photopolymerization of 1,6‐hexanediol diacrylate, MTBP show surprisingly high efficiency, and the final conversion runs up to 95.94%. magnified image
Superamphiphobic Web of PTFEMA Fibers via Simple Electrospinning Without Functionalization
Authors: Choi Gyoung‐Rin , Park Joonsik , Ha Jong‐Wook , Kim Wan‐Doo , Lim Hyuneui 
Published: October 2010

AbstractThis paper reports on a web of superamphiphobic fluoro‐compound fibers that forms as a result of a typical electrospinning method without any additional treatment. An electrospun web of poly(2,2,2‐trifluoroethyl methacrylate) fibers exhibits superamphiphobicity when the water and hexadecane contact angles both exceed 150°. The morphology of a web is modulated by changing the polymer solution concentration from 24 to 30 wt.‐% with other fixed processing conditions. The fiber diameter length depends mainly on the polymer concentration. A web formed from a 26 wt.‐% solution has the smallest and most uniform fiber diameter; it also has the highest robustness parameter on wetting, thus the highest water and hexadecane contact angles. This result offers the possibility of simple industrial production of an amphiphobic surface. magnified image
Analysis of the large‐n limit of multiple orthogonal polynomials and non‐intersecting Brownian motions
Authors: Alonso L. Martínez , Medina E. 
Published: October 2010

AbstractIn this work, we use the connection between families of multiple orthogonal polynomials with respect to a certain set of weights and random matrix models with external sources to determine the eigenvalue density and its support in the large‐n limit. These results are also applied to a model of non‐intersecting Brownian motions starting from a fix point. Copyright © 2010 John Wiley & Sons, Ltd.
Aroma WaterLOGSY: a fast and sensitive screening tool for drug discovery
Authors: Hu Jun , Eriksson Per‐Olof , Kern Gunther 
Published: October 2010

AbstractOne‐dimensional NMR spectroscopy has proven to be a powerful technique for screening compound libraries in drug discovery. We report a novel water ligand‐observed gradient spectroscopy (WaterLOGSY) pulse sequence, named Aroma WaterLOGSY, that selectively detects aromatic WaterLOGSY signals from compounds or ligands. In the Aroma WaterLOGSY, water magnetization is untouched after water excitation and utilizes the whole period of the remaining pulse sequence to relax back to the + z direction. Due to the phase cycling design, the water magnetization is allowed to relax for the period of two full scans before it gets inverted again. Therefore, the recycle delay can be significantly shortened. Within similar experimental time, Aroma WaterLOGSY shows approximately two times higher sensitivity than the standard scheme. This method also allows the use of non‐deuterated reagents, thereby accelerating experimental set‐up time for ligand‐binding studies. Copyright © 2010 John Wiley & Sons, Ltd.
Polystyrene microsphere–ferritin conjugates: A robust phantom for correlation of relaxivity and size distribution
Authors: Sukerkar Preeti A. , Rezvi Uzma G. , MacRenaris Keith W. , Patel Pinal C. , Wood John C. , Meade Thomas J. 
Published: October 2010

AbstractIn vivo iron load must be monitored to prevent complications from iron overload diseases such as hemochromatosis or transfusion‐dependent anemias. While liver biopsy is the gold standard for determining in vivo iron load, MRI offers a noninvasive approach. MR phantoms have been reported that estimate iron concentration in the liver and mimic relaxation characteristics of in vivo deposits of hemosiderin. None of these phantoms take into account the size distribution of hemosiderin, which varies from patient to patient based on iron load. We synthesized stable and reproducible microsphere‐ferritin conjugates (ferribeads) of different sizes that are easily characterized for several parameters that are necessary for modeling such as iron content and bead fraction. T1s and T2s were measured on a 1.41‐T low‐resolution NMR spectrometer and followed a size‐dependent trend. Ferribeads imaged at 4.7 and 14.1 T showed that signal intensities are dependent on the distribution of ferritin around the bead rather than the iron concentration alone. These particles can be used to study the effects of particle size, ferritin distribution, and bead fraction on proton relaxation and may be of use in mimicking hemosiderin in a phantom for estimating iron concentration. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Estimation of tensors and tensor‐derived measures in diffusional kurtosis imaging
Authors: Tabesh Ali , Jensen Jens H. , Ardekani Babak A. , Helpern Joseph A. 
Published: October 2010

AbstractThis article presents two related advancements to the diffusional kurtosis imaging estimation framework to increase its robustness to noise, motion, and imaging artifacts. The first advancement substantially improves the estimation of diffusion and kurtosis tensors parameterizing the diffusional kurtosis imaging model. Rather than utilizing conventional unconstrained least squares methods, the tensor estimation problem is formulated as linearly constrained linear least squares, where the constraints ensure physically and/or biologically plausible tensor estimates. The exact solution to the constrained problem is found via convex quadratic programming methods or, alternatively, an approximate solution is determined through a fast heuristic algorithm. The computationally more demanding quadratic programming‐based method is more flexible, allowing for an arbitrary number of diffusion weightings and different gradient sets for each diffusion weighting. The heuristic algorithm is suitable for real‐time settings such as on clinical scanners, where run time is crucial. The advantage offered by the proposed constrained algorithms is demonstrated using in vivo human brain images. The proposed constrained methods allow for shorter scan times and/or higher spatial resolution for a given fidelity of the diffusional kurtosis imaging parametric maps. The second advancement increases the efficiency and accuracy of the estimation of mean and radial kurtoses by applying exact closed‐form formulae. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Vascular therapy for radiation cystitis
Authors: Soler Roberto , Vianello Alberto , Füllhase Claudius , Wang Zhan , Atala Anthony , Soker Shay , Yoo James J. , KoudyWilliam James 
Published: October 2010

AbstractPurposeThe underlying pathology of radiation cystitis is cellular and vascular damage followed by increased fibrosis and inflammation. This study was to determine if neovascular‐promoting therapy could reduce the pathological changes in the bladder wall associated with pelvic irradiation.MethodsAdult female Lewis inbred rats were irradiated with a single dose of 20 Gy directed at their bladder. Four weeks later, 30 rats were divided equally into one of three treatment groups for bladder wall injection of: (1) PBS (Control); (2) PBS containing 50 ng vascular endothelial growth factor (VEGF165); or (3) PBS containing 1 × 106 rat endothelial cells (EC). Age‐matched non‐irradiated rats (n = 10) served as untreated controls. At either 1.5 or 3 months following radiation, bladders were analyzed for collagen deposition using Masson's Trichrome staining of collagen and muscle and vascularization using Von Willebrand factor staining of ECs. Quantitative‐PCR was used to examine markers of angiogenesis, hypoxia, and fibrosis.ResultsThe collagen/muscle ratio was doubled in the control group 3 months post‐irradiation (P < 0.05 vs. non‐irradiated bladders). Both ECs and VEGF inhibited increases in collagen content (P < 0.05 vs. control). Similarly, irradiation reduced bladder wall vessel counts compared to non‐irradiated controls (P < 0.05) and both ECs and VEGF maintained vessel counts similar to that of non‐irradiated controls (P < 0.05). PCR analysis showed a higher expression of neovascular markers (CD31, KDR) in the EC and VEGF groups compared to non‐irradiated controls (P < 0.05).ConclusionsAngiogenesis therapy may be useful in the prevention and/or treatment of the underlying pathology of radiation cystitis. Neurourol. Urodynam. 30:428–434, 2011. © 2010 Wiley‐Liss, Inc.
Decomposing inventory routing problems with approximate value functions
Authors: Toriello Alejandro , Nemhauser George , Savelsbergh Martin 
Published: October 2010

AbstractWe present a time decomposition for inventory routing problems. The methodology is based on valuing inventory with a concave piecewise linear function and then combining solutions to single‐period subproblems using dynamic programming techniques. Computational experiments show that the resulting value function accurately captures the inventory's value, and solving the multiperiod problem as a sequence of single‐period subproblems drastically decreases computational time without sacrificing solution quality. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Approximation results for min‐max path cover problems in vehicle routing
Authors: Xu Zhou , Xu Liang , Li Chung‐Lun 
Published: October 2010

AbstractThis article studies a min‐max path cover problem, which is to determine a set of paths for k capacitated vehicles to service all the customers in a given weighted graph so that the largest path cost is minimized. The problem has wide applications in vehicle routing, especially when the minimization of the latest service completion time is a critical performance measure. We have analyzed four typical variants of this problem, where the vehicles have either unlimited or limited capacities, and they start from either a given depot or any depot of a given depot set. We have developed approximation algorithms for these four variants, which achieve approximation ratios of max{3 ‐ 2/k,2}, 5, max{5 ‐ 2/k,4}, and 7, respectively. We have also analyzed the approximation hardness of these variants by showing that, unless P = NP, it is impossible for them to achieve approximation ratios less than 4/3, 3/2, 3/2, and 2, respectively. We have further extended the techniques and results developed for this problem to other min‐max vehicle routing problems.© 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Hybrid‐Trefftz stress element for bounded and unbounded poroelastic media
Authors: de Freitas J. A. Teixeira , Moldovan I. D. 
Published: October 2010

AbstractThe equations that govern the dynamic response of saturated porous media are first discretized in time to define the boundary value problem that supports the formulation of the hybrid‐Trefftz stress element. The (total) stress and pore pressure fields are directly approximated under the condition of locally satisfying the domain conditions of the problem. The solid displacement and the outward normal component of the seepage displacement are approximated independently on the boundary of the element. Unbounded domains are modelled using either unbounded elements that locally satisfy the Sommerfeld condition or absorbing boundary elements that enforce that condition in weak form. As the finite element equations are derived from first‐principles, the associated energy statements are recovered and the sufficient conditions for the existence and uniqueness of the solutions are stated. The performance of the element is illustrated with the time domain response of a biphasic unbounded domain to show the quality of the modelling that can be attained for the stress, pressure, displacement and seepage fields using a high‐order, wavelet‐based time integration procedure. Copyright © 2010 John Wiley & Sons, Ltd.
Coupling finite elements and finite volumes by Lagrange multipliers for explicit dynamic fluid–structure interaction
Authors: Casadei Folco , Leconte Nicolas 
Published: October 2010

AbstractThis paper proposes a strategy for coupling a Finite Element description of structures with a Finite Volume (FV) description of fluids by means of the Lagrange multipliers method, for the numerical simulation of Fluid–Structure Interaction problems in fast transient dynamics. The structural domain uses the classical explicit Central Difference (CD) time integration scheme, while in the fluid domain a node‐centered Finite Volume scheme is adopted, which achieves second‐order accuracy in space and in time by a predictor–corrector algorithm combined with a MUSCL‐like technique. The FV time marching scheme is suitably adapted to enable ‘strong’ coupling with the CD scheme via Lagrange multipliers. Numerical examples illustrate the effectiveness of the proposed procedure. Copyright © 2010 John Wiley & Sons, Ltd.
Efficient non‐linear model reduction via a least‐squares Petrov–Galerkin projection and compressive tensor approximations
Authors: Carlberg Kevin , Bou‐Mosleh Charbel , Farhat Charbel 
Published: October 2010

AbstractA Petrov–Galerkin projection method is proposed for reducing the dimension of a discrete non‐linear static or dynamic computational model in view of enabling its processing in real time. The right reduced‐order basis is chosen to be invariant and is constructed using the Proper Orthogonal Decomposition method. The left reduced‐order basis is selected to minimize the two‐norm of the residual arising at each Newton iteration. Thus, this basis is iteration‐dependent, enables capturing of non‐linearities, and leads to the globally convergent Gauss–Newton method. To avoid the significant computational cost of assembling the reduced‐order operators, the residual and action of the Jacobian on the right reduced‐order basis are each approximated by the product of an invariant, large‐scale matrix, and an iteration‐dependent, smaller one. The invariant matrix is computed using a data compression procedure that meets proposed consistency requirements. The iteration‐dependent matrix is computed to enable the least‐squares reconstruction of some entries of the approximated quantities. The results obtained for the solution of a turbulent flow problem and several non‐linear structural dynamics problems highlight the merit of the proposed consistency requirements. They also demonstrate the potential of this method to significantly reduce the computational cost associated with high‐dimensional non‐linear models while retaining their accuracy. Copyright © 2010 John Wiley & Sons, Ltd.
Finite element modelling of saturated porous media at finite strains under dynamic conditions with compressible constituents
Authors: Gajo A. , Denzer R. 
Published: October 2010

AbstractTwo finite element formulations are proposed to analyse the dynamic conditions of saturated porous media at large strains with compressible solid and fluid constituents. Unlike similar works published in the literature, the proposed formulations are based on a recently proposed hyperelastic framework in which the compressibility of the solid and fluid constituents is fully taken into account when geometrical non‐linear effects are relevant on both micro‐ and macroscales. The first formulation leads to a three‐field finite element method (FEM), which is suitable for analysing high‐frequency dynamic problems, whereas the second is a simplification of the first, leading to a two‐field FEM, in which some inertial effects of the pore fluid are disregarded, hence the second formulation is suitable for studying low‐frequency problems. A fully Lagrangian approach is considered, hence all terms are expressed with reference to the material setting; the balance equations for the pore fluid are also expressed in terms of the chemical potential and the mass flux of the pore fluid in order to take the compressibility of the fluid into account. To improve the numerical response in the case of wave propagation, a discontinuous Galerkin FEM in the time domain is applied to the three‐field formulation. The results are compared with analytical and semi‐analytical solutions, highlighting the different effects of the discontinuous Galerkin method on the longitudinal waves of the first and second kind. Copyright © 2010 John Wiley & Sons, Ltd.
Optimal component mode synthesis for medium frequency problem
Authors: Herran Mathieu , Nélias Daniel , Combescure Alain , Chalons Hervé 
Published: October 2010

AbstractThe component mode synthesis (CMS) with fixed interface (denoted Craig–Bampton) method uses a combination of static and dynamic modes. The usual definition of this CMS leads to a coupling between static and dynamic modes which are not orthogonal with respect to the stiffness matrix. This type of basis is not well suited for dynamic explicit computations, because the resulting mass matrix is not diagonal. If one keeps the same basis mode set but uses an orthogonalization process with respect to the mass matrix, the quality of the reduced Craig–Bampton system is kept but the basis vectors are combined differently. The aim of this paper is to propose a new way to control the accuracy of the reduced dynamic system for a specific frequency domain. Thus a new CMS is defined in order to be accurate in the medium frequency range. Copyright © 2010 John Wiley & Sons, Ltd.
Multiscale XFEM‐modelling and simulation of the inelastic material behaviour of textile‐reinforced polymers
Authors: Kästner M. , Haasemann G. , Ulbricht V. 
Published: October 2010

AbstractThis paper addresses the multiscale simulation of fibre‐reinforced polymers. The considered composite materials exhibit a hierarchical material structure with three distinct length scales—micro, meso and macro. This feature of the morphology allows for the application of homogenization techniques based on a representative volume element (RVE) that is entirely typical for the local, periodic material structure. The effective macroscopic material behaviour of the composite can be predicted from the properties of the individual constituents and the geometric arrangement of the reinforcing fibres based on the simulation of the material behaviour in the RVE.The heterogeneous material structure in an RVE is modelled by the eXtended finite element method (XFEM). To this, two special element types, called X‐element and 2X‐element, are derived. They can represent one or two material interfaces within the element domain. For an efficient modelling process, an automated model generation procedure that determines the required element types, locates the material interfaces and performs the subdivision of the X‐elements into tetrahedral integration domains has been developed. Problems related to a consistent interface approximation and a continuous displacement field are discussed.In the generated RVE models, a viscoplastic material model accounts for the inelastic material behaviour of the polymeric matrix, whereas the glass‐fibres are assumed to have a linear elastic stress–strain behaviour. Using periodic displacement boundary conditions, effective stress–strain curves are computed for glass‐fibre‐reinforced polypropylene with unidirectional and woven arrangements of the reinforcing fibres. Copyright © 2010 John Wiley & Sons, Ltd.
GPU accelerated lattice Boltzmann model for shallow water flow and mass transport
Authors: Tubbs Kevin R. , Tsai Frank T.‐C. 
Published: October 2010

AbstractA lattice Boltzmann method (LBM) for solving the shallow water equations (SWEs) and the advection–dispersion equation is developed and implemented on graphics processing unit (GPU)‐based architectures. A generalized lattice Boltzmann equation (GLBE) with a multiple‐relaxation‐time (MRT) collision method is used to simulate shallow water flow. A two‐relaxation‐time (TRT) method with two speed‐of‐sound techniques is used to solve the advection–dispersion equation. The proposed LBM is implemented to an NVIDIA®Computing Processor in a single GPU workstation. GPU computing is performed using the Jacket GPU engine for MATLAB®and CUDA. In the numerical examples, the MRT‐LBM model and the TRT‐LBM model are verified and show excellent agreement to exact solutions. The MRT outperforms the single‐relaxation‐time (SRT) collision operator in terms of stability and accuracy when the SRT parameter is close to the stability limit of 0.5. Mass transport with velocity‐dependent dispersion in shallow water flow is simulated by combining the MRT‐LBM model and the TRT‐LBM model. GPU performance with CUDA code shows an order of magnitude higher than MATLAB‐Jacket code. Moreover, the GPU parallel performance increases as the grid size increases. The results indicate the promise of the GPU‐accelerated LBM for modeling mass transport phenomena in shallow water flows. Copyright © 2010 John Wiley & Sons, Ltd.