bluuebunny/crossref_metadata_2025_split huggingface dataset:
An operator‐split ALE model for large deformation analysis of geomaterials
Authors: Di Y. , Yang J. , Sato T. 
Published: January 2007

AbstractAnalysis of large deformation of geomaterials subjected to time‐varying load poses a very difficult problem for the geotechnical profession. Conventional finite element schemes using the updated Lagrangian formulation may suffer from serious numerical difficulties when the deformation of geomaterials is significantly large such that the discretized elements are severely distorted. In this paper, an operator‐split arbitrary Lagrangian–Eulerian (ALE) finite element model is proposed for large deformation analysis of a soil mass subjected to either static or dynamic loading, where the soil is modelled as a saturated porous material with solid–fluid coupling and strong material non‐linearity. Each time step of the operator‐split ALE algorithm consists of a Lagrangian step and an Eulerian step. In the Lagrangian step, the equilibrium equation and continuity equation of the saturated soil are solved by the updated Lagrangian method. In the Eulerian step, mesh smoothing is performed for the deformed body and the state variables obtained in the updated Lagrangian step are then transferred to the new mesh system. The accuracy and efficiency of the proposed ALE method are verified by comparison of its results with the results produced by an analytical solution for one‐dimensional finite elastic consolidation of a soil column and with the results from the small strain finite element analysis and the updated Lagrangian analysis. Its performance is further illustrated by simulation of a complex problem involving the transient response of an embankment subjected to earthquake loading. Copyright © 2007 John Wiley & Sons, Ltd.
Inexact Barzilai‐Borwein method for saddle point problems
Authors: Hu Yi‐Qing , Dai Yu‐Hong 
Published: January 2007

AbstractThis paper considers the inexact Barzilai–Borwein (BB) algorithm applied to saddle point problems. To this aim, we study the convergence properties of the inexact BB algorithm for symmetric positive definite linear systems. Suppose thatgkandg̃kare the exact residual and its approximation of the linear system at thekth iteration, respectively. We prove theR‐linear convergence of the algorithm if ∥g̃k–gk∥⩽η∥g̃k∥ for some small η>0 and allk. To adapt the algorithm for solving saddle point problems, we also extend theR‐linear convergence result to the case when the right‐hand term ∥g̃k∥ is replaced by ∥g̃k–1∥. Although our theoretical analyses cannot provide a good estimate to the parameter η, in practice, we find that η can be as large as the one in the inexact Uzawa algorithm. Further numerical experiments show that the inexact BB algorithm performs well for the tested saddle point problems. Copyright © 2007 John Wiley & Sons, Ltd.
Preconditioning CGNE iteration for inverse problems
Authors: Egger H. 
Published: January 2007

AbstractThe conjugate gradient method applied to the normal equations (CGNE) is known as efficient method for the solution of non‐symmetric linear equations. By stopping the iteration according to a discrepancy principle, CGNE can be turned into a regularization method, and thus can be applied to the solution of inverse, in particular, ill‐posed problems. We show that CGNE for inverse problems can be further accelerated by preconditioning in Hilbert scales, derive (optimal) convergence rates with respect to data noise, and give tight bounds on the iteration numbers. The theoretical results are illustrated by numerical tests. Copyright © 2007 John Wiley & Sons, Ltd.
Modified Hermitian and skew‐Hermitian splitting methods for non‐Hermitian positive‐definite linear systems
Authors: Li Liang , Huang Ting‐Zhu , Liu Xing‐Ping 
Published: January 2007

AbstractTo further study the Hermitian and non‐Hermitian splitting methods for a non‐Hermitian and positive‐definite matrix, we introduce a so‐called lopsided Hermitian and skew‐Hermitian splitting and then establish a class of lopsided Hermitian/skew‐Hermitian (LHSS) methods to solve the non‐Hermitian and positive‐definite systems of linear equations. These methods include a two‐step LHSS iteration and its inexact version, the inexact Hermitian/skew‐Hermitian (ILHSS) iteration, which employs some Krylov subspace methods as its inner process. We theoretically prove that the LHSS method converges to the unique solution of the linear system for a loose restriction on the parameter α. Moreover, the contraction factor of the LHSS iteration is derived. The presented numerical examples illustrate the effectiveness of both LHSS and ILHSS iterations. Copyright © 2007 John Wiley & Sons, Ltd.
The retraction algorithm for factoring banded symmetric matrices
Authors: Kaufman Linda 
Published: January 2007

Abstract
Let A be an n × n symmetric matrix of bandwidth 2m + 1. The matrix need not be positive definite. In this paper we will present an algorithm for factoring A which preserves symmetry and the band structure and limits element growth in the factorization. With this factorization one may solve a linear system with A as the coefficient matrix and determine the inertia of A, the number of positive, negative, and zero eigenvalues of A. The algorithm requires between 1/2nm2 and 5/4nm2 multiplications and at most (2m + 1)n locations compared to non‐symmetric Gaussian elimination which requires between nm2 and 2nm2 multiplications and at most (3m + 1)n locations. Our algorithm reduces A to block diagonal form with 1 × 1 and 2 × 2 blocks on the diagonal. When pivoting for stability and subsequent transformations produce non‐zero elements outside the original band, column/row transformations are used to retract the bandwidth. To decrease the operation count and the necessary storage, we use the fact that the correction outside the band is rank‐1 and invert the process, applying the transformations that would restore the bandwidth first, followed by a modified correction. This paper contains an element growth analysis and a computational comparison with LAPACKs non‐symmetric band routines and the Snap‐back code of Irony and Toledo. Copyright © 2007 John Wiley & Sons, Ltd.
An inverse problem in estimating the relaxation time for nanoscale phonon radiative transfer problem
Authors: Huang Cheng‐Hung , Chen Kuan‐Yu , Kim Sin 
Published: January 2007

AbstractAn inverse nanoscale phonon radiative transfer problem is solved in this study by using conjugate gradient method (CGM) to estimate the unknown frequency‐ and temperature‐dependent relaxation time, based on the simulated phonon intensity measurements. The CGM in dealing with the present integro‐differential governing equations is not as straightforward as for the normal differential equations; special treatments are needed to overcome the difficulties. Results obtained in this inverse analysis will be justified based on the numerical experiments where two different unknown distributions of relaxation time are to be estimated. Finally, it is shown that the reliable frequency and temperature‐dependent relaxation time can be obtained with CGM. Copyright © 2007 John Wiley & Sons, Ltd.
A simple computer implementation of membrane wrinkle behaviour via a projection technique
Authors: Akita T. , Nakashino K. , Natori M. C. , Park K. C. 
Published: January 2007

AbstractA simple computer implementation of membrane wrinkle behaviour is presented within the classical elastic plane stress constitutive model. In the present method, a projection technique is utilized for modelling of the wrinkle mechanisms, in which the total strains in wrinkled membranes are decomposed into elastic and zero‐strain energy parts, and a projection matrix that extracts the elastic parts from the total strains is derived. The resulting modified elasticity matrix that represents the stress–strain relations in wrinkled membranes is thus obtained as product of the classical elasticity matrix and the projection matrix. The modified elasticity matrix is straightforward to implement within the context of the finite element method. Numerical examples are presented to demonstrate the accuracy and effectiveness of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic identification of fractal structures
Authors: Tesar Alexander , Melcer Jozef 
Published: January 2007

AbstractDynamic identification of fractal structures mapping the configurations from the nature and adopted in advanced structural engineering is dealt with in the present paper. Theoretical, numerical and experimental assessments are based on wave approaches and back‐propagation neural network models corresponding with genetic algorithms. Some structural applications based on such assessments are presented. Copyright © 2007 John Wiley & Sons, Ltd.
A discontinuous Galerkin method for a hyperbolic model for convection–diffusion problems in CFD
Authors: Gómez H. , Colominas I. , Navarrina F. , Casteleiro M. 
Published: January 2007

AbstractThis paper proposes a hyperbolic model for convection–diffusion transport problems in computational fluid dynamics (CFD). The hyperbolic model is based on the so‐called Cattaneo's law. This is a time‐dependent generalization of Fick's and Fourier's laws that was originally proposed to solve pure‐diffusive heat transfer problems. We show that the proposed model avoids the infinite speed paradox that is inherent in the standard parabolic model.A high‐order upwind discontinuous Galerkin (DG) method is developed and applied to classic convection‐dominated test problems. The quality of the numerical results is remarkable, since the discontinuities are very well captured without the appearance of spurious oscillations. These results are compared with those obtained by using the standard parabolic model and the local DG (LDG) method and with those given by the parabolic model and the Bassi–Rebay scheme.Finally, the applicability of the proposed methodology is demonstrated by solving a practical case in engineering. We simulate the evolution of pollutant being spilled in the harbour of A Coruña (northwest of Spain, EU). Copyright © 2007 John Wiley & Sons, Ltd.
On some fluid–structure iterative algorithms using pressure segregation methods. Application to aeroelasticity
Authors: Badia Santiago , Codina Ramon 
Published: January 2007

AbstractIn this paper we suggest some algorithms for the fluid–structure interaction problem stated using a domain decomposition framework. These methods involve stabilized pressure segregation methods for the solution of the fluid problem and fixed point iterative algorithms for the fluid–structure coupling. With one single loop the solution of the coupled system tends to one of the strongly coupled monolithic systems. These coupling algorithms are applied to the aeroelastic simulation of suspension bridges. We assess flexural and torsional frequencies for a given inflow velocity. Increasing this velocity we reach the value for which the flutter phenomenon appears. Copyright © 2007 John Wiley & Sons, Ltd.
An investigation into blood donation intentions among non‐donors
Authors: Reid Mike , Wood Angela 
Published: January 2007

Abstract
In broad terms, the donation of blood along with organ and bone marrow donation is considered to be the ultimate act of humanity involving a voluntary and anonymous exchange between two people of a life saving commodity. Yet motivating people to donate blood is a significantly difficult task. The aim of this paper is to use the Theory of Planned Behaviour (TPB) to examine non‐donors on the basis of their likely intention to donate blood in the future and to identify barriers on these more favourable non‐donors. This exploratory research finds that subjective norm, perceived behavioural control and time related barriers are related to intent to donate by current non‐donors. Differences between higher and lower intention donors are also explored.
Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and characterization of poly(L‐lactide‐co‐ε‐ caprolactone) copolymers: influence of sequential monomer addition on chain microstructure
Authors: Nalampang K. , Molloy R. , Punyodom W. 
Published: January 2007

AbstractA series of copolymers with various compositions were synthesized by one‐step and two‐step bulk ring‐opening polymerizations of L‐lactide (LA) and ε‐caprolactone (CL) using stannous octoate [Sn(Oct)2] and 1‐hexanol as the initiating system. For the sequential two‐step polymerization, a poly(ε‐caprolactone) (PCL) prepolymer was polymerized first to a percent conversion of approximately 70% and LA then added in order to produce a copolymer with a chain microstructure different from that obtained from the corresponding one‐step reaction. The resulting copolymers were characterized using a combination of nuclear magnetic resonance spectroscopy (1H‐ and 13C‐NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). The average sequence lengths of the lactidyl ($l_{{\rm LL}}^{\rm e}$) and caproyl ($l_{{\rm cap}}^{\rm e}$) units, the degree of randomness (R) and the transesterification coefficient (T(II)) were calculated from the 13C‐NMR spectra. The appearance of a signal due to CapLCap sequences was directly attributable to transesterification of lactidyl (LL) units. It was found that both $l_{{\rm LL}}^{\rm e}$ and $l_{{\rm cap}}^{\rm e}$ values from the two‐step syntheses were significantly longer than from the corresponding one‐step syntheses, leading to different semi‐crystalline morphologies and chain microstructures. The copolymers all showed at least some blocky chain structure as a result of the significant difference in monomer reactivity (LA > CL) between LA and CL. Thermal properties including stability depended on both composition and chain microstructure which could be controlled by the method of synthesis. From their DSC curves, the two‐step copolymers were seen to be semi‐crystalline whereas the one‐step copolymers were mainly amorphous. A more blocky microstructure, as obtained from the two‐step method, appeared to result in a lower thermal stability. Copyright © 2007 John Wiley & Sons, Ltd.
Fatal adenovirus hepatitis during maintenance therapy for childhood acute lymphoblastic leukemia
Authors: Steiner Isabelle , Aebi Christoph , Ridolfi Lüthy Annette , Wagner Bendicht , Leibundgut Kurt 
Published: February 2007

AbstractDisseminated adenoviral infection with hepatitis is rare in children undergoing standard chemotherapy. We report on a 3½‐year‐old male with fatal adenovirus hepatitis receiving maintenance chemotherapy for acute lymphoblastic leukemia (ALL). Adenoviral hepatitis was proven by histology, viral culture, and PCR in a liver biopsy. Quantitative real‐time PCR in the peripheral blood showed adenoviral DNA copy number >109/ml. Despite aggressive supportive care and antiviral treatment with cidofovir, the patient died rapidly due to fulminant liver failure. Diagnostic and treatment options for adenovirus infection remain unsatisfactory for these patients. We propose suggestions for diagnosis and therapy. Pediatr Blood Cancer 2008;50:647–649. © 2007 Wiley‐Liss, Inc.
Successful treatment with modified CHOP‐rituximab in pediatric AIDS‐related advanced stage Burkitt lymphoma
Authors: Crosswell Howland E. , Bergsagel Daniel J. , Yost Robert , Lew Glen 
Published: February 2007

AbstractBurkitt lymphoma is the most common AIDS‐related lymphoma (ARL) in childhood. The major issues in adult and pediatric ARL include identifying the optimal chemotherapy regimen and the concurrent treatment of both rituximab and highly active anti‐retroviral therapy (HAART). We present a case of advanced stage Burkitt lymphoma in an 8‐year‐old female with acquired immunodeficiency syndrome (AIDS), who was successfully treated with a 3 month course of modified CHOP‐R (cyclophosphamide, daunorubicin, vincristine, prednisone, and rituximab) and HAART therapy. The combination of rituximab and chemotherapy with HAART therapy may be well‐tolerated and effective in HIV/AIDS patients with Burkitt lymphoma. Pediatr Blood Cancer 2008;50:883–885. © 2007 Wiley‐Liss, Inc.
Synthesis and characterization of cross‐shaped p–n diblock oligomers
Authors: Wang Hong‐Yu , Wan Jun‐Hua , Jiang Hong‐Ji , Wen Gui‐An , Feng Jia‐Chun , Zhang Zhi‐Jian , Peng Bo , Huang Wei , Wei Wei 
Published: February 2007

AbstractThe cross‐shaped p–n diblock oligomers based on oligothiophenes (OTs) and 1,3,4‐oxadiazole (OXD) were synthesized and investigated regarding optical properties, electrochemistry, quantum chemical calculations, and intramolecular energy transfer. Since only one emission peak is observed in PL spectra of the oligomers, it is evidenced that effective energy transfer from the OXD to OTs branch. The electrochemical experiments show that almost complete spatial separation of HOMO and LUMO with the thiophene number increasing. The theoretical calculations were carried out regarding which conformer is the lowest in energy, the torsion angle between thiophene/oxadiazole and the central benzene ring, and electron densities distributions of the oligomers. Based on all data, a model for intramolecular energy‐transfer process has been put forward to explain the optical properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1066–1073, 2007
Novel electroluminescent cationic polyelectrolyte based on poly[(fluorene‐2,7‐diylvinylene)‐alt‐(1,4‐phenylenevinylene)] and its precursor
Authors: Mikroyannidis John A. , Barberis Vasilis P. , Cimrová Věra 
Published: February 2007

AbstractA novel conjugated poly[(fluorene‐2,7‐vinylene)‐alt‐(1,4‐phenylenevinylene)] derivative 2 with quaternizable tertiary amino groups was synthesized by Heck coupling of a substituted 2,7‐dibromofluorene and 1,4‐dialkoxy‐2,5‐divinylbenzene. The corresponding quaternary ammonium cationic polyelectrolyte 3 was obtained by the treatment of 2 with bromoethane. Both polymers were soluble in common organic solvents, like tetrahydrofuran, chloroform, and dichloromethane. Polymer 3 showed a limited solubility in alcohols and was insoluble in water. Photophysical and electrochemical properties of the resulting polymers were fully investigated. An intensive green photoluminescence (PL) with maxima at 550 and 545 nm was observed from thin films of 2 and 3 polymers, respectively, red‐shifted compared with the PL emission spectra measured in the solution. The electrochemical band gaps were 2.38–2.45 eV. Single‐layer and double‐layer (with poly[3,4‐(ethylenedioxy)thiophene]/poly (styrenesulfonate) (PEDOT:PSS)) light‐emitting devices (LEDs) with ITO and Al electrodes were prepared and studied. They emitted a green light and their electroluminescence (EL) spectra were similar to those of PL thin films. The external EL efficiency was determined to be 0.43 and 0.32% for ITO/PEDOT:PSS/2/Al and ITO/PEDOT:PSS/3/Al LEDs, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1016–1027, 2007
Thermodynamic model of gas permeability in polymer membranes
Authors: Lee Do Kyoung , Kim Yong Woo , Lee Kyung Ju , Min Byoung Ryul , Kim Jong Hak 
Published: February 2007

AbstractA new molecular thermodynamic model is developed of the gas permeability in polymer membranes on the basis of configurational entropy and Flory‐Huggins theory to predict permeability dependence on the concentration of penetrant. Three kinds of configurational entropy are taken into account by this model; that is, the disorientation entropy of polymer, the mixing entropy, and specific interaction entropy of polymer/gas. The validity of the mathematical model is examined against experimental gas permeability for polymer membranes. Agreement between experimental and predicted permeability is satisfactory. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 661–665, 2007
Magnetoresistance, transport noise and granular structure in polycrystalline superconductors
Authors: García‐Fornaris I. , Govea‐Alcaide E. , Muné P. , Jardim R. F. 
Published: February 2007

AbstractIn this work we present a theoretical study on the magnetic field dependence of the electrical resistance R (Ba) and the transport noise (TN) in a high‐Tc polycrystalline superconductors. In the model, we have considered the ceramic superconductor as a series‐parallel array of Josephson devices and the intergranular magnetic field is described within the framework of the intragranular flux‐trapping model. The obtained results qualitatively reproduce the hysteretic behavior of the R (Ba) dependence in increasing and decreasing applied magnetic fields. We have found that the hysteretic behavior in the R (Ba) dependence changes appreciably if different statistical distributions of the geometric factors of grains are used. In addition, such changes are also reflected in the TN, which is produced by the electric current rearrangement in the array with increasing applied magnetic fields. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonparametric confidence intervals for Tmax in sequence‐stratified crossover studies
Authors: Willavize Susan A. , Morgenthien Elizabeth A. 
Published: January 2007

AbstractTmax is the time associated with the maximum serum or plasma drug concentration achieved following a dose. While Tmax is continuous in theory, it is usually discrete in practice because it is equated to a nominal sampling time in the noncompartmental pharmacokinetics approach. For a 2‐treatment crossover design, a Hodges–Lehmann method exists for a confidence interval on treatment differences. For appropriately designed crossover studies with more than two treatments, a new median‐scaling method is proposed to obtain estimates and confidence intervals for treatment effects. A simulation study was done comparing this new method with two previously described rank‐based nonparametric methods, a stratified ranks method and a signed ranks method due to Ohrvik. The Normal theory, a nonparametric confidence interval approach without adjustment for periods, and a nonparametric bootstrap method were also compared. Results show that less dense sampling and period effects cause increases in confidence interval length. The Normal theory method can be liberal (i.e. less than nominal coverage) if there is a true treatment effect. The nonparametric methods tend to be conservative with regard to coverage probability and among them the median‐scaling method is least conservative and has shortest confidence intervals. The stratified ranks method was the most conservative and had very long confidence intervals. The bootstrap method was generally less conservative than the median‐scaling method, but it tended to have longer confidence intervals. Overall, the median‐scaling method had the best combination of coverage and confidence interval length. All methods performed adequately with respect to bias. Copyright © 2007 John Wiley & Sons, Ltd.