bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pathophysiology of spastic paresis. II: Emergence of muscle overactivity
Authors: Gracies Jean‐Michel 
Published: February 2005

AbstractIn the subacute and chronic stages of spastic paresis, stretch‐sensitive (spastic) muscle overactivity emerges as a third fundamental mechanism of motor impairment, along with paresis and soft tissue contracture. Part II of this review primarily addresses the pathophysiology of the various forms of spastic overactivity. It is argued that muscle contracture is one of the factors that cause excessive responsiveness to stretch, which in turn aggravates contracture. Excessive responsiveness to stretch also impedes voluntary motor neuron recruitment, a concept termed stretch‐sensitive paresis. None of the three mechanisms of impairment (paresis, contracture, and spastic overactivity) is symmetrically distributed between agonists and antagonists, which generates torque imbalance around joints and limb deformities. Thus, each may be best treated focally on an individual muscle‐by‐muscle basis. Intensive motor training of the less overactive muscles should disrupt the cycle of paresis–disuse–paresis, and concomitant use of aggressive stretch and focal weakening agents in their more overactive and shortened antagonists should break the cycle of overactivity–contracture–overactivity. Muscle Nerve, 2005
Insight into the flow‐condition‐based interpolation finite element approach: solution of steady‐state advection–diffusion problems
Authors: Kohno Haruhiko , Bathe Klaus Jürgen 
Published: February 2005

AbstractThe flow‐condition‐based interpolation (FCBI) finite element approach is studied in the solution of advection–diffusion problems. Two FCBI procedures are developed and tested with the original FCBI method: in the first scheme, a general solution of the advection–diffusion equation is embedded into the interpolation, and in the second scheme, the link‐cutting bubbles approach is used in the interpolation. In both procedures, as in the original FCBI method, no artificial parameters are included to reach stability for high Péclet number flows. The procedures have been implemented for two‐dimensional analysis and the results of some test problems are presented. These results indicate good stability and accuracy characteristics and the potential of the FCBI solution approach. Copyright © 2005 John Wiley & Sons, Ltd.
Identifikation von Materialparametern für ein elasto‐plastisches Materialmodell für Fichtenholz
Authors: Fleischmann Martin , Eberhardsteiner Josef , Mang Herbert A. 
Published: February 2005

AbstractAuf der Basis von biaxialen Experimenten behandelt dieser Beitrag die Identifikation von ausgewählten makroskopischen Materialparametern für ein orthotropes Einflächen‐Plastizitätsmodells für Fichtenholz. Das Hauptaugenmerk liegt in der Bestimmung der initialen Fließfläche sowie der Erfassung des Einflusses wesentlicher Holzmerkmale auf die Festigkeitseigenschaften. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Macromechanical characteristics deduced from tests on glass/epoxy composites with optical methods
Authors: Haasemann Georg , Thielsch Karin , Ulbricht Volker 
Published: February 2005

AbstractExperimental results are required to verify the simulation results obtained by the homogenisation procedure of a biaxial weftknitted fabric reinforced composite with the Binary Model [1]. Tensile, bending and shear tests were performed to investigate and validate the elastic macro‐mechanical behaviour of the composite material. Beside other methods an optical whole‐field measuring system was used to estimate the deformation in all tests. Additionally, natural frequencies and the appropriate mode shapes of plates were used to get the elements of the compliance matrix. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of Microstructural Components of Bitumen by Means of Atomic Force Microscopy (AFM)
Authors: Jäger Andreas , Lackner Roman , Eisenmenger‐Sittner Christoph , Blab Ronald 
Published: February 2005

AbstractAccounting for the large variation of asphalt mixes, resulting from variations of constituents and composition, and from the allowance of additives, a multiscale model for asphalt is currently developed at the Christian Doppler Laboratory for “Performance‐based optimization of flexible road pavements”. The multiscale concept allows to relate macroscopic material properties of asphalt to phenomena and material properties of finer scales of observation. Starting with the characterization of the finest scale, i.e., the bitumen‐scale, Atomic Force Microscopy (AFM) is employed. Depending on the mode of measurement (tapping versus pulsed‐force mode), the AFM provides insight into the surface topography or stiffness and adhesion properties of bitumen. The obtained results will serve as input for upscaling in the context of the multiscale model in order to obtain the homogenized material behavior of bitumen at the next‐higher scale, i.e., the mastic‐scale. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental Investigations on Polymeric Foams
Authors: Klar Oliver , Ehlers Wolfgang 
Published: February 2005

AbstractThe knowledge of the material behaviour of polymeric foams and their experimental investigation is the starting point for the structure of the chosen constitutive equations and for the following identification of the material constants therein. Especially for the parameter identification, it is necessary to make an adequate set of experimental data available.In this regard, it is important that the experiments make the different kinds of material behaviour visible like elastic, plastic or viscous material properties. For this reason, the foam is observed under uniaxial tension and compression and under simple shear tests combined with different deformation states in axial direction. Unfortunately, due to different reasons, e.g., the foam must be sticked on the fastener to realize the tests mentioned above, it is very difficult to initialize a homogenous deformation state in the specimen. Therefore, the experiments are recorded with a standard digital camcorder to get local information of the deformation state by tracking single points with algorithms of the digital image processing. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wavelet transformation in damage identification by dynamic tests
Authors: Knitter‐Piatkowska Anna , Garstecki Andrzej 
Published: February 2005

AbstractThe paper presents the problem of damage detection basing on the phenomenon of reflection and diffraction of waves at damage boundaries. Elastic waves in plate structures are considered. Damage is modeled as stiffness reduction at a small domain. One‐dimensional discrete signals, representing the velocity or acceleration measured at specified time and plate sections are analyzed using wavelet transform. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An experimental validation of the Stochastic Subspace Identification
Authors: Kompalka A. S. , Reese S. 
Published: February 2005

AbstractIn this contribution we derive and experimentally validate the Stochastic Subspace Identification. Additionally we compare the results with an updated finite element model. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extreme roll motions of ships
Authors: Kreuzer Edwin , Mestrom Rob , Pick Marc‐Andre 
Published: February 2005

AbstractThe ship capsizing problem is one of the major challenges in naval architecture. The criterion of the International Maritime Organization (IMO) regarding capsize stability is still not including dynamic loads. Existing mathematical models of ships taking into account all degrees of freedom as well as fluid–structure–interaction can hardly be used for stability analysis with common methods from nonlinear dynamics theory due to their complexity. For the development of new better suited models a test environment has been created. A first prototype for an experimental capsize analysis is presented in this paper. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Damage identification by wavelet transformation of data measured in thermal processes
Authors: Pozorski Zbigniew , Ziopaja Krzysztof 
Published: February 2005

AbstractDamage detection by the analysis of steady‐state or transient thermal response of a structure is studied. 2D‐wavelet transform is employed. Measurement noise in temperature field is accounted for. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parameter–identification of macroscopic material models based on virtual testing of given material mesostructures
Authors: Rieger Andreas , Miehe Christian 
Published: February 2005

AbstractFor many heterogeneous materials such as composites and polycrystals, the material modeling for the constituents on a representative mesoscale can be considered as known, including concrete values of their inherent material parameters. Typical examples are isotropic elastic–plastic models for the constituents of composites or anisotropic crystal–plasticity models for the grains of polycrystals. This knowledge can be exploited with regard to the modeling of the homogenized macroscopic response. In particular, parameters in macroscopic models may be identified by virtual experiments provided by a computational deformation–driving of representative mesostructures. This paper outlines the general concept for the parameter–identification of macroscopic materialmodels based on the virtual testing of given material mesostructures. The virtual test data are obtained in the form of multi–dimensional stress–strain paths by applying different deformation gradients to a given mesostructure. After specifying a corresponding macroscopic material model covering the observed effects on the macroscale, the material parameters are identified by a least–square–type optimization procedure that optimizes the macroscopic material parameters. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐dimensional boundary layer on wind turbine blades
Authors: Dumitrescu Horia , Cardos Vladimir 
Published: February 2005

AbstractThis paper describes a three‐dimensional analysis of the laminar boundary layer that develops on the blades of an horizontalaxis wind turbine. The main aim was to investigate a fundamental phenomenon: the effect of rotation on the blade boundary layer of a wind turbine in conjunction with the widely observed phenomenon of stall‐delay. The separation position in retarded flows with pressure gradients is calculated and compared for the rotation and non‐rotation cases. It is concluded that the stall is linearly postponed due to the Coriolis force and the separation point is delayed as a result of increasing rotation speed or decreasing blade spanwise position. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Initial Opening of a Compressor Valve
Authors: Flade Georg , Will Gotthard , Steinrück Herbert 
Published: February 2005

AbstractThe initial opening of a compressor valve is investigated. The motion of the valve plate is essentially determined by the pressure distribution in the valve gap. Since the initial gap is extremly narrow a conventional CFD solution fails. Therefore the initial stages of the opening process are modelled by using an asymptotic expansion with respect to a small asepct ratio of the valve gap. The purpose of the analysis is to provide an initial condition for a CFD simulation of the valve dynamics. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Capillary driven Oscillations of a Free Liquid Interface under Non‐Isothermal Conditions
Authors: Gerstmann Jens , Michaelis Mark , Dreyer Michael 
Published: February 2005

AbstractIn this study the reorientation behavior of a free liquid interface in a partly filled right circular cylinder upon a step reduction in gravity is investigated experimentally. The experiments focus on the investigation of non‐isothermal boundary conditions on the liquid reorientation. The situation is similar to a spacecraft which enters a ballistic flight after the end of thrust. Heat flux between the liquid propellant and the tank wall occurs and influences the behavior of the liquid reorientation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some methods of the control of the separation region behind a backward facing step
Authors: Jaňour Z. , Jonáš P. 
Published: February 2005

AbstractPreliminary experimental study was made on the prospects to affect the separation behind a backward facing step by means of suction or blowing through a gap at the foot of the step on one wall of the straight channel with rectangular cross section. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First Order LSFEM for Fluid‐Structure Problems
Authors: Kayser‐Herold Oliver , Matthies Hermann G. 
Published: February 2005

AbstractThe Least‐Squares Finite Element Method (LSFEM) is an interesting alternative to the standard variational principles, which are used to solve partial differential equations. Advantages of the LSFEM are its robustness and the resulting symmetric positive definite matrices, which allow the use of robust iterative solvers like the CG method. In this paper we consider the application of the LSFEM for Fluid‐Structure Interaction (FSI) problems. Our model uses the LSFEM for the discretisation of the instationary incompressible Navier‐Stokes equations, which is coupled with a standard Galerkin FEM model for a linear elastic structure. The results for a simple model problem agree well with results obtained by other authors with different numerical schemes. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Transonic Marginal Separation
Authors: Kluwick Alfred , Streibl Bernhard 
Published: February 2005

AbstractLaminar boundary‐layer separation near the leading edge of a thin airfoil is one of the principal factors that limits the lift force acting on the airfoil. Marginal separation, in particular, denotes the onset of separation which is accompanied by the formation of a short separation bubble. Using asymptotic analysis this effect is studied in the limit of high Reynolds number and for transonic external flow conditions. It is assumed that the fluid under consideration is a perfect gas and the airfoil surface is taken to be thermally insulated. Results to be presented include the analytical investigation of the emerging three layer structure, the associated transonic far field and the calculation of representative wall shear stress distributions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shock boundary layer interactions in dense gases
Authors: Kluwick Alfred , Wrabel Marcus 
Published: February 2005

AbstractThe concept of triple deck theory is applied to study laminar interacting boundary layers of dense gases in external purely supersonic flow. An impinging shock is generated at distances which are large compared to the upper deck thickness. As predicted by weakly nonlinear theory such a discontinuity may disintegrate into a sonic shock and an associated wave fan depending on its amplitude and the magnitude of the so called fundamental derivative. Incoming and outgoing waves are computed analytically by means of the method of multiple scales taking into account that mutual interaction effects between them are restricted to the linear upper deck region. The lower deck problem is solved numerically. The results show that it is possible to reduce the size of the separation bubble or even to avoid the occurrence of flow separation by choosing an optimal thermodynamic state. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of granular flow in silos
Authors: Leppert Caroline , Dinkler Dieter 
Published: February 2005

AbstractA numerical model for granular flow is introduced in the light of the discharging of silos. To represent the dynamic and partly structure‐damaging processes during emptying, the granular material is treated as a fluid. Therefore, the Navier‐Stokes equations can be used to describe the flow. A discretisation scheme with space‐time finite elements is applied to both structure and fluid to allow a monolithic coupling of both continua [3]. Therefore, an investigation into the interaction between granular material and walls is possible.The main part of this paper is the presentation of a constitutive model for granular media, which combines the non‐Newtonian fluid properties with the solid behaviour at rest. Bagnold [1] formulates first experimentally based relations for granular flows. Besides a number of phenomenological models, constitutive relations exist, that are derived from kinetic theory [2]. The extension of these fluid properties to the constitutive models in soil mechanics allows the description of granular flows in transition. Selected results show the influence of compressibility and inner friction to discharging phenomena. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Trailing Edge Problem For Mixed Convection Flow Past a Horizontal Plate
Authors: Savic Ljubomir , Steinrück Herbert 
Published: February 2005

AbstractThe influence of buoyancy onto the boundary‐layer flow past a horizontal plate aligned parallel to a uniform free stream is characterized by the buoyancy parameter K = Gr/Re5/2 where Gr and Re are the Grashof and Reynolds number, respectively. An asymptotiy analysis of the complete flow field including potential flow, boundary layer, wake and interaction region is given for small buoyancy parameters and large Reynolds numbers in the distinguished limit KRe1/4 = O(1). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shear stress analysis in axially symmetric flow using the Padé approximation technique
Authors: Spillane Sandra , Redmond Brendan 
Published: February 2005

AbstractThis paper evaluates the shear stress on the surface of a circular cylinder in axially symmetric flow within the boundary layer. An extended solution is obtained by established techniques, e.g. asymptotic series or Pohlhausen method. A Padé approximation technique is applied to the extended solution obtained. The region of validity of the solution is extended and the results are then compared and examined against known approximate Pohlhausen and series solutions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mathematical modelling of compressible viscous fluid flow in a male rotor‐housing gap of screw machines
Authors: Vimmr Jan 
Published: February 2005

AbstractThis contribution is devoted to the mathematical modelling of a compressible viscous fluid flow through a 2‐D model of the male rotor‐housing gap in screw machines. Numerical solution of the nonlinear conservative system of the compressible Navier‐Stokes equations is obtained by means of the cell‐centred finite volume formulation of the explicit two‐step TVD MacCormack scheme proposed by Causon on a structured quadrilateral grid using the own developed numerical code. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instationäre Strömung in einer Halbkugel
Authors: Wünsch Olaf 
Published: February 2005

AbstractEs geht um die Strömung in einer mit Flüssigkeit gefüllten Halbkugel, die um eine Achse Drehschwingungen ausführt. Im Fall eines newtonschen Fluids werden interessante Strömungsformen in der Meridianebene beobachtet, die sich mit klassischen Theorien nicht erklären lassen. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of the compatibilizer PE‐g‐GMA on the mechanical, thermal and morphological properties of virgin and reprocessed LDPE/corn starch blends
Authors: Pedroso A. G. , Rosa D. S. 
Published: February 2005

AbstractThe effects of the compatibilizer polyethylene grafted with glycidyl methacrylate (PE‐g‐GMA) on the properties of low‐density polyethylene (LDPE) (virgin and reprocessed)/corn starch blends were studied. LDPE (virgin and reprocessed)/corn starch blends containing 30, 40 and 50 wt% starch, with or without compatibilizer, were prepared by extrusion and characterized by the melt flow index (MFI), tensile test, dynamic mechanical analysis (DMTA) and light microscopy. The addition of starch to LDPE reduced the MFI values, the tensile strength and the elongation at break, whereas the modulus increased. The decreases in the MFI and tensile properties were most evident when 40 and 50 wt% starch were added. Blends containing 3 wt% PE‐g‐GMA had higher tensile strength values and lower MFI values than blends without compatibilizer. Light microscopy showed that increasing the starch content resulted in a continuous phase of starch. Copyright © 2005 John Wiley & Sons, Ltd.
Comparative study on the enzymatic polymerization of N‐substituted aniline derivatives
Authors: Nabid Mohammad Reza , Entezami Ali Akbar 
Published: February 2005

AbstractA series of water‐soluble N‐substituted poly(alkylanilines) (PNAAs) have been enzymatically synthesized with a variety of groups, from methyl to n‐butyl, such as poly(N‐methylaniline), poly(N‐ethylaniline), poly(N‐butylaniline) and poly(N‐phenylethanolamine). The syntheses were made in the presence of poly(4‐sodium styrene sulfonate) (SPS) as a template and horseradish peroxidase (HRP) as a catalyst. The size and type of the groups have a great effect on the properties of the final polymers. UV‐vis spectroscopy and cyclic voltammetry measurements confirmed that for enzymatically synthesized PNAAs/SPS complexes, the electroactivity increased with the bulkiness of the substituents. These polymers have been studied in the doped and undoped states by FT‐IR and UV‐vis spectroscopy. Also these polymers show multiple and reversible optical transitions that can be ascribed to the formation of polaron and bipolaron states. Copyright © 2005 John Wiley & Sons, Ltd.
Diffusion and permeability of aldehydes into blends of natural rubber and chemically modified low molecular weight natural rubber
Authors: Akinlabi A. K. , Okieimen F. E. , Aigbodion A. I. 
Published: February 2005

AbstractLow molecular weight natural rubber (LMWNR) obtained from natural rubber (NR) by depolymerization of natural rubber latex (NRL) was modified by epoxidation to 35% epoxide level to yield epoxidized low molecular weight natural rubber (ELMWNR). The ELMWNR was in turn modified in a solution of thioglycollic acid (TGA) (0.5 mol phr) to yield a product of 20% conversion of its initial LMWNR epoxide. Blends of NR with LMWNR, ELMWNR and epoxidized low molecular weight natural rubber thioglycollic acid (ELWMNR‐TGA) adduct were made. The mixes were vulcanized at 150°C for 20 min before determining the system parameters (n and k), the sorption (S), diffusion (D) and permeability (P) of the vulcanizates in acetaldehyde and formaldehyde solutions at three different temperatures (25, 40 and 60°C) for a period of 90 days. The sorption, diffusion and permeability of the vulcanizates were found to be temperature dependent. The vulcanizates containing ELMWNR were found not to be easily penetrated by both acetaldehyde and formaldehyde when compared with base mix A that is vulcanizates with only NR. The reaction system was found not to be spontaneous but dependent on the activation energies. Copyright © 2005 John Wiley & Sons, Ltd.