bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigations of shear free turbulent diffusion in a rotating frame
Authors: Guenther S. , Oberlack  , Brethouver G. , Johansson A. V. 
Published: December 2004

AbstractWe reconsider the problem of shear free turbulent diffusion in a rotating frame, rotating about x1. Shear free turbulence is generated at a vibrating grid in the x2–x3 plane and diffuses away from the grid in x1 direction. An important property of this flow case is that there is no mean flow‐velocity. With the help of Lie‐group methods Reynolds‐stress transport models can be analyzed for this kind of flow in a rotating frame. From the analysis it can be found, that the turbulent diffusion only influences a finite domain. Implicating this solution in the model equations shows that even fully nonlinear Reynolds‐stress transport models (non‐linear in the Reynolds‐stresses for the pressure‐strain model) are insensitive to rotation for this type of flow. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mass Transfer in Porous Media
Authors: Ricken Tim 
Published: December 2004

AbstractIn this contribution, a constitutive model based on the macromechanical Theory of Porous Media (TPM) for a saturated thermo elastic porous body has been developed. The body under investigation consists of an organic and inorganic moisturized phases and a gas phase. Based on a consistent thermomechanical treatment, the governing equations and constitutive equations will be given. Thus, we obtain a mathematical concept describing the motion of the solid phase, the pressure of the gas phase, the temperature of the mixture and the biodegradation of organic material into a gas mixture of methane and carbon dioxide produced by bacterial decomposition during stable methane fermentation (biogas). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time Domain Impedance Boundary Conditions for a Slip Mean FlowBoundary
Authors: Zhuang M. , Zheng S. , Thiele F. 
Published: December 2004

AbstractIn modeling the physical condition of an impedance boundary, the assumption of either particle displacement continuity (PDC) or particle normal velocity continuity (PVC) at the interface between the acoustic treatment and the adjacent fluid needs to be used. Although it is well accepted that the impedance boundary condition derived from the PDC is the appropriate impedance boundary condition when there is a slip mean flow at the liner surface, the time domain impedance boundary condition is however unstable due to the Kelvin‐Helmholtz instability associated with the ”vortex sheet.” In this paper, an effective time domain impedance boundary condition for a slip mean flow boundary is proposed and validated. Several relevant issues related to the PDC and PVC are discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Simulation of Two‐Phase Flows Through Injection Nozzles
Authors: Dickopp Christian , Ballmann Josef 
Published: December 2004

AbstractThe characteristic properties of an injection jet and the spray behind the exit of an injection nozzle depend on cavitation phenomena within the nozzle. The presented research project aims at modelling the distributions of pressure, velocity and phase fractions at the nozzle exit based on numerical simulation of the two‐phase flow within the nozzle. The mathematical and physical description assumes the liquid and the gas within the cavitation bubbles as compressible, viscous and heat conductive fluids and also includes dynamical processes in the mixture. The solution of the Navier‐Stokes equations for the mixture is approximated by a finite element method in two space dimensions and explicit in time using an improved FCT‐strategy to achieve nonlinear stability. Linear aspects of stability were analyzed as well, especially with respect to the used homogeneous model and provided upper bounds for the time step. The method is applied for the simulation of transient processes in one‐ and two‐phase flow through injection nozzles with constant or variable cross‐section. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local buckling of a bent flange of a thin walled beam
Authors: Stasiewicz P. , Magnucki K. , Lewiński J. , Kasprzak J. 
Published: December 2004

AbstractThe paper is devoted to stability of repeatedly bent flange of a thin‐walled beam. In classical approach each segment of the flange is considered as a simple plate. The paper provides an analytical description of the whole flange as a thin‐walled structure with the use of an energetic method. An explicit formula defining the critical load of the flange was obtained. This enables to perform a numerical analysis of a family of thin‐walled beams. Additionally, a numerical analysis with FEM was carried out. The results of both approaches have been compared. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Investigation of the Interaction of Turbulent Wind Flow and Elastic Structures
Authors: Al Farra Anas , Hübner Björn , Dinkler Dieter 
Published: December 2004

AbstractThe Interaction between wind flow and structures plays an important role in the computation of civil engineering application. In case of gravity prestressed membrane roofs, the wind lifting forces may exceed the dead load leading to high amplitude structural oscillations, which interact with the flow field. To investigate the interaction a consistent discretization method based on stabilized space‐time finite elements is applied. The flow field is modeled with the incompressible Reynolds Averaged Navier‐Stokes (RANS) equations with an anisotropic eddy‐viscosity turbulence model. The structural motion is described with the theory for geometrically nonlinear elastic deformation behavior, a strong coupling algorithm for the time‐dependent fluid‐structure interaction is implemented. Two applications show the capability of the turbulence model in representing the anisotropic turbulence structure, the differences in the flow field over a bluff body between two configurations representing a rigid and an elastic membrane roof, discusses the structural responses of the roof at a high Reynolds number. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interactive computing methods for aeroelastic analysis of turbomachinery
Authors: Dumitrache Alexandru 
Published: December 2004

AbstractAn interaction viscous‐inviscid method for efficiently computing steady and unsteady viscous flows is presented. The inviscid domain is modeled using a finite element discretization of the full potential equation. The viscous region is modeled using a finite difference boundary layer technique. The two regions are simultaneously coupled using the transpiration approach. A time linearization technique is applied to this interactive method. For unsteady flows, the fluid is assumed to be composed of a mean or steady flow plus a harmonically varying small unsteady disturbance. Numerically exact nonreflecting boundary conditions are used for the far field conditions. Results for some steady and unsteady, laminar and turbulent flow problems are compared to linearized Navier‐Stokes or time‐marching boundary layer methods. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Accurate Distance Algorithm for Octree‐Encoded Objects
Authors: Dyllong Eva , Luther Wolfram 
Published: December 2004

AbstractDistance algorithms are most frequently used in robotics to determine the distance between two obstacles in the environment of a robot or between a sensor point and an object. Bounding volumes are a common technique; this technique relies on a hierarchical model representation of the two surfaces using axis‐aligned bounding boxes. Formoving objects it is interesting to use unaligned octrees to avoid the wrapping effect that occurs when performing octree decomposition in a common coordinate system after several rotations. We discuss the algorithm for computing accurate enclosures for the distance between objects represented by axis‐aligned or unaligned octrees. This algorithm is based on a new, recently published distance algorithm between two objects represented by axis‐aligned octrees. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generierung kollisionsfreier Fahrzeugbahnen für Fahrerassistenzsysteme mittels der Theorie elastischer Bänder
Authors: Hirsch Karina , Hilgert Jens , Hiller Manfred , Bertram Torsten 
Published: December 2004

AbstractZur Verbesserung der Sicherheit im Straßenverkehr werden in Zukunft zunehmend Fahrerassistenzsysteme zur Unterstützung des Fahrers bei der Fahrzeugführung eingesetzt. Insbesondere werden für kritische Situationen Notfalltrajektorien benötigt, deren Planung mit Hilfe der Theorie der elastischen Bänder vorgenommen werden kann. Die zugehörige Ausweichbahn legt sich dabei ähnlich einem physikalischen elastischen Band um das Hindernis. Sowohl die innere Kontraktion als auch die externe Repulsion der Hindernisse werden mit Hilfe von Federpotenzialen realisiert. Lokale äußere Einflüsse auf das Band wirken sich global aus, so dass die Krümmungsänderungen minimiert und somit auch Gefahren f ür das Fahrzeug reduziert werden. Dabei werden die Trajektorien für Fahrmanöver, wie z.B. für einen Spurwechsel, und die zugehörige Ausweichbahn durch kubische Splines generiert. Die fahrdynamische Realisierbarkeit der generierten Notfalltrajektorie unter den gegebenen Randbedingungen, wie Fahrzeuggeschwindigkeit und Witterungsverhältnisse, wird mit Hilfe eines auf ein Fahrdynamikmodell angewandtes Least‐Squares‐Verfahren vorab sichergestellt. Das vorgestellte theoretische Verfahren ist Bestandteil eines deutsch‐niederländischen Kooperationsprojektes und wird am Beispiel des Szenarios einer Kolonnenfahrt auf einer mehrspurigen Fahrbahn mit Ein‐ und Ausfädelvorgängen einzelner Fahrzeuge demonstriert. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New Aspects For Bifurcation Problems in Continuous Mechanics
Authors: Sburlan Cristina , Sburlan Silviu 
Published: December 2004

AbstractConsider a semilinear eigenvalue problem

where λ ∈ R, the linear operator $ \cal L $ is defined in a real Hilbert space H and $ \cal N $ : H → H is generaly a nonlinear perturbation.We can define a coincidence degree of the pair ($ \cal L, \cal N $) under some conditions weaker than the ones when the classical coincidence degree was defined. Our final purpose is to extend the results to the case of the operators from the Banach space X into its dual X*, using the representation theorem due to Browder and Ton.We use these results to study resonance problems in mechanics of continua, such as the buckling in finite elastostatics and the steady state flow of incompressible fluids. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimally matched wavelets
Authors: Thielemann Henning 
Published: December 2004

AbstractSeveral applications require to retrieve a certain pattern from a signal where the actual scaling of the pattern is not known before. We consider applications like evaluation of mass spectrograms, detection of component wearout by observing the current of an engine, detection of pollutions of rotor spinning machines, decomposition of (audio) signals into time‐frequency atoms.We try to solve this problem with discrete wavelet transforms where the wavelet function is constructed to match the given pattern. An approach for a biorthogonal basis constructed by the lifting scheme is presented. This method is rather simple and fast and allows the choice of the smoothness at least of the primal wavelet in a very natural way. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New Accurate Expressions in C‐XSC
Authors: Lüderitz Kolberg Mariana , Amaral Hölbig Carlos , Bohlender Gerd , Moraes Claudio Dalcidio 
Published: December 2004

AbstractC‐XSC is a programming library for Extended Scientific Computing which supports many data types with high accuracy. However, it does not provide the accurate expressions which are already available in the older language PASCAL‐XSC. These expressions have to be replaced by long loops that are more difficult to understand. Therefore, we studied possibilities how these accurate expressions could be implemented in C‐XSC. In this paper we present possibilities like operator overloading with special result types avoiding rounding errors, and a small pre‐processor which converts accurate expressions to function calls. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Random Vibration of the Uncertain Parametric Micro‐Periodic Beam ‐ General Solution
Authors: Mazur‐Sniady K. , Sniady P. 
Published: December 2004

AbstractThe subject of the analysis are random vibrations of the beam having uncertain periodic structure. It is assumed that excitation load is described by stationary or nonstationary stochastic process. The parameters of the beam have the uncertain nature and are described by random variables. The problem is solved using the tolerance averaging procedure, the stochastic Green function and the perturbation method. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reliability of Deterioration System
Authors: Sniady Pawel , Sieniawska Roza , Zukowski Stanislaw 
Published: December 2004

AbstractMathematical models of the reliability assessment of a structure treated as the time to the first passage of the capacity which is degrading in the time are presented. Two stochastic models of the structure degradation caused by different factors and two stochastic models of loading are considered. The relationships for calculating the probability of failure for presented models of the structure load and the capacity degradation, are given. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization in aircraft engineering including approximate structural evaluations by support vector machines
Authors: Kaletta Peter , Wolf Klaus , Fischer Andreas , Löschner Kristina 
Published: December 2004

AbstractThe minimum weight design of structures made of fiber reinforced composite materials leads to a class of mixed‐integer optimization problems for which evolutionary algorithms (EA) are well suited. Based on these algorithms the optimization tool package GEOPS has been developed at TU Dresden.For each design generated by an EA the structural response has to be evaluated. This is often based on a finite element analysis which results in a high computational complexity for each single design. Typical runs of EA require the evaluation of thousands of designs. Thus, an efficient approximation of the structural response could improve the performance considerably. To achieve this aim the constraints on the structural response are approximated by means of support vector machines (SVM). It is trained by means of exact structural evaluations for selected design alternatives only. Several ways to enhance the efficiency of such an optimization procedure are presented.As an example for a typical aircraft structure, a stiffened composite panel under compressive and shear loading is considered. The SVM is trained on geometrical and material data. Representing the design space of composite panels by ABD matrices turned out to be a valuable means for obtaining well trained SVMs. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of Mechanically Coupled Composite Pipes by Genetic Algorithms
Authors: Luxner M. H. , Daxner T. , Rammerstorfer F. G. 
Published: December 2004

AbstractThe optimization of composite components with regard to minimum weight and maximum load bearing capacity in consideration of multiple constraints is an optimization problem of rather high complexity. Genetic Algorithms are a good choice for solving such problems. In this paper the formulation of a Genetic Algorithm for the simultaneous optimization of two thin walled, mechanically coupled composite pipes subjected to a combination of thermal and mechanical loads is presented. The optimization goal is the minimization of the total mass of the pipe arrangement taking into account multiple design constraints. It is shown that Genetic Algorithms are valueable tools for solving optimization problems with a large number of parameters. Furthermore, it is possible to find additional, perhaps practicable, close‐to‐optimal configurations as a byproduct of the optimization process. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flow Optimization on Traffic Networks
Authors: Kumari Singh Anita , Herty Michael , Klar Axel 
Published: December 2004

AbstractThis work has been motivated by the work of [1]. Here in traffic models for networks based on PDE's are considered. A simplified algebraic model is derived from PDE‐based model. Optimization problem is to minimize cost functional measuring properties of network flows. We use a new approach to solve the minization problem for the reformulated algebraic model. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Weight‐Reduction of Sandwich Structures by an Efficient Topology Optimization Technique
Authors: Tapp Christian , Hansel Wilfried , Mittelstedt Christian , Becker Wilfried 
Published: December 2004

AbstractA heuristic algorithm for the weight minimization of sandwich structures by a specific kind of topology optimization is presented. The method employs a preexisting algorithm for the layerwise topology optimization of symmetric laminates under in‐plane loads and expands this method for the case of bending. During the optimization procedure the algorithm adds or subtracts material from the layers of the face sheets and the core of the sandwich plate in regions of high or low stresses respectively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimality Conditions for Mechanical Impacts
Authors: Yunt Kerim , Glocker Christoph 
Published: December 2004

AbstractIn this report the necessary conditions for optimal non‐smooth control of rigid body mechanical systems with multiple impacts will be stated in accordance with Pontryagin's Minimum Principle. Criteria based on the Weierstrass‐Erdmann (WE) conditions and contemporary impact theory will be established in order to assess the optimality of an impact.The determination of post‐impact state and costate values from the pre‐impact values will be possible in some cases. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Eye lens proteomics: from global approach to detailed information about phakinin and gamma E and F crystallin genes
Authors: Hoehenwarter Wolfgang , Kumar Nalin M. , Wacker Maik , Zimny‐Arndt Ursula , Klose Joachim , Jungblut Peter R. 
Published: December 2004

AbstractExploration of the lenticular proteome poses a challenging and worthwhile undertaking as cataracts, the products of a disease phenotype elicited by this proteome, remains the leading cause of vision impairment worldwide. The complete ten day old lens proteome of Mus musculus C57BL/6J was resolved into 900 distinct spots by large gel carrier ampholyte based 2‐DE. The predicted amino acid sequences of all 16 crystallins ubiquitous in mammals were corroborated by mass spectrometry (MS). In detailed individual spot analyses, the primary structure of the full murine C57BL/6J beaded filament component phakinin CP49 was sequenced by liquid chromatography/electrospray ionization‐tandem MS and amended at two positions. This definitive polypeptide sequence was aligned to the mouse genome, thus identifying the entire C57BL/6J genomic coding region. Also, two murine C57BL/6J polypeptides, both previously classified as gamma F crystallin, were clearly distinguished by MS and electrophoretic mobility. Both were assigned to their respective genes, one of the polypeptides was reclassified as C57BL/6J gamma E crystallin. Building on these data and previous investigations an updated crystallin reference map was put forth and several non crystallin lenticular components were examined. These results represent the first part of a comprehensive investigation of the mouse lens proteome (http://www.mpiib‐berlin.mpg.de/2D‐PAGE) with emphasis on understanding genetic effects on proteins and disease development.
Transcriptomic and proteomic responses of human renal HEK293 cells to uranium toxicity
Authors: Prat Odette , Berenguer Frédéric , Malard Véronique , Tavan Emmanuelle , Sage Nicole , Steinmetz Gérard , Quemeneur Eric 
Published: December 2004

AbstractThe industrial use of uranium, in particular depleted uranium, has pin‐pointed the need to review its chemical impact on human health. Global methodologies, applied to the field of toxicology, have demonstrated their applicability to investigation of fine molecular mechanisms. This report illustrates the power of toxicogenomics to evaluate the involvement of certain genes or proteins in response to uranium. We particularly show that 25% of modulated genes concern signal transduction and trafficking, that the calcium pathway is heavily disturbed and that nephroblastomas‐related genes are involved (WIT‐1, STMN1, and STMN2). A set of 18 genes was deregulated whatever the concentration of toxicant, which could constitute a signature of uranium exposure. Moreover, a group of downregulated genes, with corresponding disappearing proteins (HSP90, 14‐3‐3 protein, HMGB1) in two‐dimensional polyacrylamide gel electrophoresis (2‐D PAGE), are good candidates for use as biomarkers of uranium effects. These results reveal a cross‐checking between transcriptomic and proteomic technologies. Moreover, our temporal gene expression profiles suggest the existence of a concentration threshold between adaptive response and severe cell deregulation. Our results confirm the involvement of genes already described and also provide new highlights on cellular response to uranium.
Phosphoproteomic analysis using immobilized metal ion affinity chromatography on the basis of cellulose powder
Authors: Feuerstein Isabel , Morandell Sandra , Stecher Guenther , Huck Christian W. , Stasyk Taras , Huang Hong‐Lei , Teis David , Huber Lukas A. , Bonn Guenther K. 
Published: December 2004

AbstractDetailed characterization of phosphoproteins as well as other post‐translationally modified proteins such as glycoproteins, is required to fully understand protein function and regulatory events in cells and organisms. Therefore, an experimental strategy for the isolation of phosphoproteins using a new immobilized metal ion affinity chromatography (IMAC) material on the basis of cellulose has been developed and characterized. Different approaches have been used to test the material. Recovery rates were determined by 32P labelling of a myelin basic protein fragment and by reversed‐phase high‐performance liquid chromatography‐electrospray ionization mass spectrometry using a tryptic digest of the model protein bovine β‐casein. Selectivity was demonstrated by enrichment and separation of phosphopeptides from different samples, such as from a digest of horse myoglobin as well as from a digest of in vitro phosphorylated extracellular signal regulated kinase 2 (ERK2) mixed with synthetic phosphopeptides, phosphorylated on different amino acid residues. Furthermore, simplification and optimization of sample pretreatment was achieved by combining the separating (IMAC) and desalting (C18) step during preparative high performance liquid chromatography. The comparison between our material and a commercially available IMAC system (POROS 20 MC; Perseptive BioSystems) emphasizes the competitiveness of the cellulose. Confirmed by the obtained data, the cellulose material performed as well as the commercially available sorbent, however with the advantage, that it can be produced rather easily and at very low cost.