bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regular boundary integral solution with dual and complementary variational formulations applied to two‐dimensional Laplace problems
Authors: Sun Y. , Kagawa Y. 
Published: August 2005

AbstractRegular boundary integral elements are employed for the dual and complementary variational formulations of Laplace problems. The problems are defined only on the boundary as usual, but as in the manner of charge simulation method (CSM), the source terms are arranged outside the domain so that the singular integral can be avoided. The Laplace problems are analysed and the usefulness of the formulation is discussed in comparison with direct BEM. The scalar potential and electric displacement vector potential functions are used in the dual and complementary formulations, with which the upper and lower bounds of the system energy or the capacitance can also accurately be evaluated.
A frequency‐independent circuit model of a conductor under surge conditions
Authors: Davies A. E. , Tong Y. K. , Lewin P. L. , German D. M. 
Published: August 2005

AbstractThis paper presents a circuit‐based model of a current carrying conductor that can provide instantaneous ohmic losses under surge conditions. The model is frequency independent and can be used to calculate transient current characteristics of surges on overhead transmission lines. The theoretical current distribution under lightning surge conditions is used to demonstrate the validity of the model and the results are compared with values obtained using a finite element analysis package. There is a good correlation between the two methods with the circuit‐based model having the advantages of being less cumbersome, requiring shorter computation time and being simple to implement in transient analysis packages.
The approximation of two‐fluid plasma flow with explicit upwind scemes
Authors: Schneider R. , Munz C.‐D. 
Published: August 2005

AbstractA non‐stationary longitudinal model of a thermal two‐component plasma is investigated with numerical methods based on so‐called high‐resolution schemes. The inhomogeneous model system is solved numerically applying a splitting method, where the homogeneous conservation laws for the electrons and ions are approximated by explicit Godunov‐type schemes. Coupling of both plasma components is achieved by the electric field, which is also calculated in an explicit manner after reformulating Coulomb's law. A new numerical method is proposed for the expansion of the plasma into the vacuum. This tracking method is based on the solution of the vacuum Riemann problem and avoids the difficulties of numerical approximation introduced by the vacuum where the longitudinal plasma model is not valid. This new approach of tracking resolves sharply the plasma vacuum interface and captures this boundary very well during the temporal evolution of the model system. Two test problems show the interplay, the quality and properties of the approximation methods applied.
Efficient modelling of curved surfaces by planar patches and wire grids for electromagnetic scattering
Authors: Heras Fernando Las , Jambrina J. L. Fernández 
Published: August 2005

AbstractThe scattering of conducting regular polyhedrons of resonant size is studied by means of the electrical field integral equation (EFIE) and the method of moments (MoM). Two models are generated for each polyhedron, a wire grid model and a triangular patch model. Two numerical codes associated with those modelling techniques are used to obtain the radar cross section (RCS) of the polyhedrons. The calculated results are compared with the analytical results of the scattering of a perfectly conducting sphere. Practical criteria relating geometric properties of the sphere and the polyhedrons are investigated for the modelling of curved surfaces by facets in electromagnetic simulations.
The climate of Scotland over the last 5000 years inferred from multiproxy peatland records: inter‐site correlations and regional variability
Authors: Langdon Peter G. , Barber Keith E. 
Published: August 2005

AbstractThe mid to late‐Holocene climates of most of Scotland have been reconstructed from seven peat bogs located across north–south and east–west geographical and climatological gradients. The main techniques used for palaeoclimatic reconstruction were plant macrofossil, colorimetric humification, and testate amoebae analyses, which were supported by a radiocarbon‐based chronology, aided by markers such as tephra isochrons and recent rises in pine pollen and in spheroidal carbonaceous particles (SCPs). Field stratigraphy was undertaken at each site in order to show that the changes detected within the peat profiles were replicable. Proxy climate records were reconstructed using detrended correspondence analysis (DCA) of the plant macrofossil data and a mean water table depth transfer function on the testate amoebae data. These reconstructions, coupled with the humification data, were standardised for each site and used to produce a composite record of bog surface wetness (BSW) from each site. The results show coherent wet and dry phases over the last 5000 years and suggest regional differences in climate across Scotland, specifically between northern and southern Scotland. Distinct climatic cycles are identified, all of which record a millennial‐scale periodicity which can be correlated with previously identified marine and ice core Holocene cycles. The key role of the macrofossil remains of Sphagnum imbricatum, a taxon now extinct on many sites, is discussed in relation to the identified climatic shifts. Copyright © 2005 John Wiley & Sons, Ltd.
Sea surface temperature record off central Japan since the Last Glacial Maximum using planktonic foraminiferal Mg/Ca thermometry
Authors: Sagawa Takuya , Toyoda Kazuhiro , Oba Tadamichi 
Published: August 2005

AbstractWe conducted paired measurements of the Mg/Ca ratio and δ18O of planktonic foraminifera, Globigerina bulloides, from a sediment core (MD01‐2420) off central Japan in the northwest Pacific, to reconstruct current movements since the Last Glacial Maximum (LGM). These methods make it possible to determine the magnitude and timing of the sea surface temperature (SST) changes and to reconstruct the variations of the past seawater δ18O (δ18Ow) off central Japan. The amplitude of Mg/Ca‐based SST changes between the Holocene and the LGM was about 10°C. The strong resemblance of the SSTs estimated from both methods, Mg/Ca‐based and δ18O‐based, suggests that the SST changes were caused primarily by latitudinal displacement of the Kuroshio–Oyashio currents and no distinct change in the carbonate dissolution of the core. The southward migration of the water mass was 5–6° in latitude at the LGM. The values for regional δ18Ow changes, which were obtained by subtracting the ice volume contribution from the calculated δ18Ow, describe the millennial‐scale water mass migration over the last 30 kyr. Copyright © 2005 John Wiley & Sons, Ltd.
Control of Helical Sense and Tightness of Amino Acid‐Based Poly(N‐propargylamide) by Temperature and Solvents
Authors: Zhao Haichao , Sanda Fumio , Masuda Toshio 
Published: August 2005

AbstractSummary: Poly(N‐(α‐tert‐butoxycarbonyl)‐L‐aspartic acid β‐cyclohexyl ester N′‐propargylamide) [poly(1)] was synthesized by the polymerization of the corresponding monomer 1 catalyzed by (nbd)Rh+[η6‐C6H5B−(C6H5)3] in CH2Cl2 at 30 °C for 2 h. Poly(1) was soluble in CH2Cl2, CHCl3, THF, and partly soluble in DMF. The specific rotation, CD, and UV‐vis spectroscopic data revealed that poly(1) exists in a helical structure in CH2Cl2, CHCl3, CHCl3/DMF, and CHCl3/MeOH. Poly(1) underwent thermo‐ and solvent‐driven switch of helical sense, accompanying the change of tightness.Schematic representation of the synthesis of the here discussed L‐aspartic acid‐based novel polyacetylene.imageSchematic representation of the synthesis of the here discussed L‐aspartic acid‐based novel polyacetylene.
Reactive Extrusion of Starch‐Polyacrylamide Graft Copolymers: Effects of Monomer/Starch Ratio and Moisture Content
Authors: Finkenstadt Victoria L. , Willett Julious L. 
Published: August 2005

AbstractSummary: The effects of monomer/starch feed ratios and moisture content during reactive extrusion of starch‐polyacrylamide graft copolymers were investigated. Acrylamide/starch ratios ranged from 0.20 to 1.87 at 50% moisture content, while moisture content was increased from 45 to 75% with an acrylamide/starch ratio of 0.33. Average conversion was 86.6% (±3.5%), independent of monomer content, at acrylamide/starch ratios of 0.77 and less. Conversion increased to approximately 95% when the acrylamide/starch ratio exceeded unity. Molecular weight of grafted polyacrylamide increased as the acrylamide/starch ratio increased. Graft efficiency was constant at approximately 75% for monomer/starch ratios of 0.77 or less, and decreased to 52.3% as the monomer/starch ratio increased to 1.87. Higher acrylamide/starch ratios gave more frequent grafts of higher molecular weight. As moisture content decreased from 75 to 45%, conversion and graft content increased from 78 and 14% to 97 and 23%, respectively. Lower moisture content gave fewer grafts of higher molecular weight. Ungrafted polyacrylamide homopolymer increased with monomer/starch ratio and moisture content. These results indicate that graft copolymer properties can be controlled through the monomer/starch ratio and moisture content during reactive extrusion.Molecular weight distributions of grafted polyacrylamide at different moisture contents during extrusion: A) 75%; B) 65%; C) 55%; D) 45%.imageMolecular weight distributions of grafted polyacrylamide at different moisture contents during extrusion: A) 75%; B) 65%; C) 55%; D) 45%.
Psychogenic tremor disorders identified using tree‐based statistical algorithms and quantitative tremor analysis
Authors: Piboolnurak Panida , Rothey Natalia , Ahmed Anwar , Ford Blair , Yu Qiping , Xu Dong , Pullman Seth L. 
Published: August 2005

AbstractDetecting psychogenic tremors (PsychT) is often challenging. As there are no laboratory investigations or imaging techniques that can confirm the diagnosis, PsychT is identified on a clinical basis. We present a tree‐based statistical algorithm derived from quantitative computerized tremor recordings as a novel method to help in the recognition of PsychT. The goal of this study was to show that objective data from computerized tremor recordings, when processed through a tree‐based statistical algorithm, can be used to determine whether a patient can be classified as having PsychT. © 2005 Movement Disorder Society
Relationship between eye symptoms and blepharospasm: A multicenter case–control study
Authors: Martino Davide , Defazio Giovanni , Alessio Giovanni , Abbruzzese Giovanni , Girlanda Paolo , Tinazzi Michele , Fabbrini Giovanni , Marinelli Lucio , Majorana Giovanni , Buccafusca Maria , Vacca Laura , Livrea Paolo , Berardelli Alfredo 
Published: August 2005

AbstractAlthough patients with primary blepharospasm (BSP) commonly report experiencing ocular symptoms before the onset of orbicular spasms, the precise frequency and pathogenic role of this subjective ocular discomfort are poorly understood. We conducted a multicenter case–control study to investigate symptoms related to disorders of the anterior segment of the eye, administering a questionnaire to 165 patients with BSP and 180 age‐ and gender‐matched control patients with hemifacial spasm. On a validation sample, our questionnaire yielded high accuracy in detecting eye diseases (predominantly, dry eye syndrome) using detailed ophthalmological examination as the criterion. Logistic regression analysis indicated a significant association between ocular symptoms at disease onset and BSP. Ocular symptoms starting in the year preceding disease onset (short‐latency symptoms) showed a stronger association with BSP than ocular symptoms occurring earlier in time (long‐latency symptoms). The association was stronger when short‐latency symptoms developed from 40 to 59 years of age, whereas this was not observed for long‐latency symptoms. Our findings support the view that eye symptoms associated with BSP result from eye diseases and may be involved in the pathogenesis of BSP. The differential risk of developing BSP, based on age at onset of ocular symptoms, suggests that age and eye diseases may interact in giving rise to BSP. © 2005 Movement Disorder Society
Dopaminergic influence on disturbed spatial discrimination in Parkinson's disease
Authors: Shin Hae‐Won , Kang Suk Y. , Sohn Young H. 
Published: August 2005

AbstractVarious sensory symptoms and disturbed sensory perception are often observed in patients with idiopathic Parkinson's disease (PD). The basis of sensory disturbance in PD is unknown but possibly reflects a role for the basal ganglia in sensory processing. To investigate the relationship between the sensory dysfunction and dopaminergic deficiency in PD, we measured spatial discrimination using the Grating Orientation Task in 21 drug‐naive patients with PD, before and after long‐term antiparkinson therapy, and 25 age‐matched healthy controls. The grating orientation threshold was significantly higher in patients (3.03 ± 0.84) than controls (2.03 ± 0.79). After 3 to 10 months of antiparkinson therapy, the grating orientation threshold was significantly lowered (2.66 ± 0.84), although it was still higher than that in controls. Improvement in the patients' sensory function was significantly correlated with motor improvement (r = 0.44). These results suggest that sensory dysfunction in Parkinson's disease is related at least in part to the dopaminergic deficit. © 2005 Movement Disorder Society
On the construction of global weak solutions in the Kynch theory of sedimentation
Authors: Bustos María Cristina , Concha Fernando 
Published: August 2005

AbstractWe construct global weak solutions to the different modes of sedimentation appearing in the theory of Kynch and show that, with constant initial concentration, only five modes of sedimentation exist. We also generalize the method of construction to the case of a monotonically decreasing initial concentration.
The Sommerfeld half‐plane problem revisited, IV: Variations on a theme of Carlson and Heins
Authors: Heins A. E. , Pond J. M. 
Published: August 2005

AbstractA plane wave is incident upon an infinite set of equally spaced, semi‐infinite parallel and staggered plates. The boundary conditions on the plates alternate between the Dirichlet and Neumann ones. This problem is formulated as a pair of coupled Wiener‐Hopf integral equations and solved by a method proposed by A. E. Heins in 1950. For the case of specular reflection, that is, a single reflected plane wave, the magnitudes of the reflection coefficient and the transmission coefficients are determined.
Sturm‐Liouville eigenvalue problems on networks
Authors: von Below Joachim 
Published: August 2005

AbstractThe description of heat conduction on ramified wires, for instance, leads to a Sturm‐Liouville eigenvalue problem on a network. It is shown that these problems are special canonical eigenvalue problems in the sense of Hölder, and therefore they can be investigated within the theory of S‐Hermitian eigenvalue problems. In particular, Wielandt's expansion theorem can be applied in order to obtain eigenfunction expansions.
An evolution equation with non‐local non‐linearities: Existence, uniqueness and asymptotic behaviour
Authors: Miletta Peter D. 
Published: August 2005

AbstractAn evolution equation with non‐linearities of non‐local type is investigated. Under various hypotheses on the non‐linearities global existence and uniqueness of solutions to initial value problems is shown. Moreover the asymptotic behaviour of the solutions is determined by topological dynamics methods.
On the radius continuity of the models of polytropic gas spheres which correspond to the positive solutions of the generalized Emden‐Fowler equation
Authors: Batt J. , Pfaffelmoser K. 
Published: August 2005

AbstractWe completely answer the question which positive solutions of the Emden‐Fowler equation
equation image
, n > ½, m > − 1, m+n > 0 induce models of polytropic gas spheres of finite radius or finite mass. We continue and complete the investigation of the radius continuity of these models initiated by van den Broek and Verhulst8 in connection with a numerical analysis by Hénon7.
Unique continuation for Schrödinger operators and for higher powers of the Laplacian
Authors: Łaba Izabella 
Published: August 2005

AbstractIn this paper we consider the unique continuation property for Schrödinger operators and its application for proving the non‐existence of positive eigenvalues (embedded in the continuous spectrum). We also use the estimate given by Jerison and Kenig9 to prove unique continuation for higher powers of the Laplace operator.
On spline approximation for a class of integral equations. I: Galerkin and collocation methods with piecewise polynomials
Authors: Elschner Johannes 
Published: August 2005

AbstractWe consider the numerical solution of a class of one‐dimensional non‐compact integral equations by Galerkin and collocation methods and their iterated variants, using piecewise polynomials as basis functions. In particular, we obtain new results for the stability of the approximation methods, without any restriction on the norm of the integral operators. Furthermore, we extend results of Chandler and Graham4,6 concerning error estimates and superconvergence to a more general class of operators.
On a weakly formulated exterior problem from linear hydrodynamics
Authors: Doppel K. , Schomburg B. 
Published: August 2005

AbstractIn this paper we investigate a certain exterior boundary value problem for the inhomogeneous Helmholtz equation. We give sufficient conditions for the unique solvability of a weak formulation of this problem and show an interior regularity result for all weak solutions. As a special case the incompresible, irrotational and stationary fluid flow around a totally immersed obstacle (submarine problem) is included.
Some remarks on Newton–Sabatier methods
Authors: Carroll Robert , Delic George , Gilbert R. P. 
Published: August 2005

AbstractIt is shown how Newton–Sabatier methods (arising in inverse scattering at fixed energy) can be related to spectral measures and typically when they correspond to regular potentials. A number of spectral formulae for various transmutation kernels are also given in terms of general Kontorovič–Lebedev theory and connections to generating functions, generalized orthogonal polynomials, etc. are indicated.
Almost global existence of solutions of quasi‐linear hyperbolic equations
Authors: Milani Albert J. , Brosowski B. 
Published: August 2005

AbstractWe consider the quasi‐linear hyperbolic initial value problem (1) of the Introduction, and prove that for any T>0 there is a bound such that if the norm of the initial data is smaller than that bound then the solution of (1) exists on all of [0, T].
On the continuation for variational inequalities depending on an eigenvalue parameter
Authors: Miersemann Erich , Mittelmann Hans D. , Törnig W. 
Published: August 2005

AbstractIn this paper we generalize recent theoretical results on the local continuation of parameter‐dependent non‐linear variational inequalities. The variational inequalities are rather general and describe, for example, the buckling of beams, plates or shells subject to obstacles. Under a technical hypothesis that is satisfied by the simply supported beam, we obtain the existence of a continuation of both the solution and the eigenvalue with respect to a local parameter. A numerical continuation method is presented that easily overcomes turning points. Numerical results are presented for the non‐linear beam.
Multiple scales expansions for eddy current computation in layered media
Authors: Chiampi M. , Negro A. , Serra E. , Eckhaus W. 
Published: August 2005

AbstractAn asymptotic expansion is derived by the multiple scales method for the electromagnetic potential in a one‐dimensional model problem for eddy current computations in periodic non‐homogeneous layered media in presence of an integral constraint for each period.Error estimates for approximations with partial sums of any order are established. Numerical computations of correctors up to the fourth order are performed and the results are compared with the exact solution in some significant cases.
A global existence theorem for the general coagulation–fragmentation equation with unbounded kernels
Authors: Stewart I. W. , Meister E. 
Published: August 2005

AbstractIn this article an existence theorem is proved for the coagulation–fragmentation equation with unbounded kernel rates. Solutions are shown to be in the space X+ = {c∈L1: ∫ (1 + x)∣c(x)∣dx < ∞} whenever the kernels satisfy certain growth properties and the non‐negative initial data belong to X+. The proof is based on weak L1 compactness methods applied to suitably chosen approximating equations.
Resonance phenomena for a class of partial differential equations of higher order in cylindrical waveguides
Authors: Lesky P. , Werner P. 
Published: August 2005

AbstractWe consider a domain Ω in ℝn of the form Ω = ℝl × Ω′ with bounded Ω′ ⊂ ℝn−l. In Ω we study the Dirichlet initial and boundary value problem for the equation ∂ u + [(− ∂ −… − ∂)m + (− ∂ −… − ∂)m]u = fe−iωt. We show that resonances can occur if 2m ≥ l. In particular, the amplitude of u may increase like tα (α rational, 0<α<1) or like in t as t∞∞. Furthermore, we prove that the limiting amplitude principle holds in the remaining cases.
Pseudo‐transparent boundary conditions for the diffusion equation. Part I
Authors: Joly P. , Nedelec J. C. 
Published: August 2005

AbstractIn this article, we introduce and study a family of artificial boundary conditions for the diffusion equation. These conditions are local in time and non‐local in space. We describe the principle of the approximation, show that the corresponding approximate problems are mathematically well‐posed and give convergence results, as well as error estimates, of the approximate solution to the exact one.
Free‐boundary values in an elastic‐plastic torsion problem
Authors: Ting Tsuan Wu , Hsiao C. G. 
Published: August 2005

AbstractConsider a cylindrical pipe twisted by terminal couples. For a large twist θ, the elastic‐plastic stress function, Ψ (·,θ), is shown to be the positive in the interior of the pipe, an increasing function of θ and converging to the completely plastic stress function, \documentclass{article}\pagestyle{empty}\begin{document}$ \bar \Psi \left(\cdot \right) $\end{document} (·), as θ→∞. A geometric procedure for constructing Ψ(·) has been developed to provide qualitative information. The main result states that \documentclass{article}\pagestyle{empty}\begin{document}$ \psi \left({\cdot,\theta} \right) = \bar \Psi \left(\cdot \right) $\end{document} on the cross‐sectional boundary of the pipe, if θ is greater than or equal to a certain critical value, In addition, an example has been constructed to give additional insights.
A free boundary problem and stability for the rectangular plate
Authors: Miersemann Erich , Mittelmann Hans D. 
Published: August 2005

AbstractIn the recent paper [13] we have answered the question of stability for the linear circular plate which is being axially compressed by a force greater than the critical value and contacts a plane obstacle. In this case there are radially symmetric solutions and the contact region is a disk of a smaller radius. This simplified the determination of the critical parameter values for which the plane jumps to another state. For the rectangular plate continuation has to be applied to the variational inequality in order to determine the contact region and evalute the stability criterion. A numerical method is developed for a discretization of the problem and is used to compute the critical load both in the simply supported and the clamped case.