bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimentelle Ermittlung einer vibroakustischen Zielfunktion für die aktiveRegelung von Plattenstrukturen
Authors: Vogl Bernd 
Published: April 2003

AbstractFür die Entwicklung aktiver Struktursysteme, die u.a. auf die akustische Verbesserung von Bauteilen abzielen, ist die Kenntnis des Zusammenhangs zwischen dem dynamischen Verhalten und dem dadurch induzierten Luftschallfeld notwendig. In einer vorangegangenen Arbeit [1] wurde die theoretische Ermittlung einer vibroakustischen Zielfunktion analytisch am Beispiel einer allseitig gelenkig gelagerten Rechteckplatte gezeigt. Die Übertragung der gewonnenen Erkenntnisse auf ein Experiment mit einer fest eingespannten Rechteckplatte soll hier vorgestellt werden. Über eine Experimentelle Modalanalyse (EMA) lässt sich die Volumenverschiebung, die zur abgestrahlten Schallleistung unterhalb der Koinzidenzfrequenz korreliert [2], diskretisiert als Zielfunktion ermitteln. Die Rekonstruktion dieser Zielfunktion mittels geometrisch äquidistant verteilter, strukturapplizierter piezokeramischer Sensoren (PZT‐Patches) ist das Ziel der Untersuchung. Die Güte der Rekonstruktion wird in dieser Arbeit ebenfalls diskutiert. Die Integration der rekonstruierten Zielfunktion in einen aktiven Regelkreis ist ein weiterführendes Ziel dieser Arbeit.
A nondestructive experimental approach for heat flux determination on direct‐chill cast aluminium alloy billet surface
Authors: Založnik M. , Šarler B. , Bajsić I. 
Published: April 2003

AbstractIn this paper a new nondestructive experimental method for the determination of the billet surface heat flux in direct‐chill casting of aluminium alloys is presented. The new measurement method is based on measurements of the water film temperatures along the billet surface and determination of the local heat flux from the energy balance. Experiments using the new technique are carried out in a real plant environment. The results are used for the validation of a computational model of the process.
Comparison of the Solution of the Riemann Problem for Inviscid/Viscous Flows
Authors: Dykas S. , Goodheart K.A. , Schnerr G.H. 
Published: April 2003

AbstractThe aim of this paper is to present the influence of the method used to solve the convective fluxes on the transonic internal flow field. The governing equations are discretized using an upwind method based on different solutions of the Riemann problem, flux vector splitting (FVS) or flux difference splitting schemes (FDS). Turbulence effects are simulated by means of the low‐Reynolds‐number k – ϵ and the SST (Shear‐Stress‐Transport) turbulence models.
Details on the Computation of Hypersonic Inlet Flows
Authors: Reinartz B. , Ballmann J. 
Published: April 2003

AbstractWithin the frame of the Collaborative Research Center (SFB) “Fundamentals of Design of Aerospace Planes”, the design criteria of hypersonic engine inlet flows are studied computationally as well as experimentally. Of special interest are geometrical considerations with respect to the attainable total pressure recovery as well as the thermal load on the engine structure. Thus, the length and base angle of the exterior compression ramps are varied and their influence on the overall pressure gain is investigated. In addition, the length of the subsequent isolator/diffusor, responsible for the interior flow compression, is analyzed with emphasis on the total pressure loss.
Strömungsmechanische und rheooptische Untersuchungen viskoelastischer Flüssigkeiten in turbulenten Kanalströmungen
Authors: Gampert B. , Brämer T. , Eich T. 
Published: April 2003

AbstractIn dieser Arbeit wurden strömungsmechanische und rheooptische Experimente an viskoelastischen Flüssigkeiten in der vollausgebildeten turbulenten Kanalströmung durchgeführt. Dabei wurden das Turbulenzverhalten und die Orientierung der Makromoleküle in der Strömung mit Hilfe der Laser‐Doppler‐Anemometrie (LDA) und dem Verfahren der strömungsinduzierten Doppelbrechung (FIB) für verschieden konzentrierte Polymerlösungen untersucht. Es wird der Zusammenhang zwischen rheologischen und turbulenten Ergebnissen diskutiert.
Driftflussmodell für unstrukturierte Netze mit Partikelagglomeration
Authors: Javurek Mirko 
Published: April 2003

AbstractEin Driftflussmodell (oder auch algebraisches Mischungsmodell genannt) kann in Mehrphasen‐CFD‐Simulationen eingesetzt werden, wenn die Sekundärphasen Partikel, Tropfen oder Blasen sind. Das Geschwindigkeitsfeld der Sekund ärphase wird berechnet, indem die Driftgeschwindigkeit (die von der Partikelgröße abhängt) zum Geschwindigkeitsfeld der Primärphase addiert wird. Für jede Sekundärphase wird nur eine zusätzliche Transportgleichung gelöst. Deswegen ist das Driftlussmodell im Vergleich mit Euler‐Euler‐Modellen ein sehr robustes, stabiles und schnelles Modell um Mehrphasenströmungen zu berechnen. Bei Implementierungen des Driftlussmodells für unstrukturierte Gitter können Probleme an Wänden auftreten, an denen die Partikel das Rechengebiet nicht verlassen können und sich dort ansammeln (Agglomeration). Diese Probleme und eine Lösungsidee sind in dieser Arbeit geschildert.
Unsteady Cavitation in Injection Nozzles ‐ Dynamic Interaction of Internal Flow and Jet Formation ‐
Authors: Yuan Weixing , Schnerr Günter H. , Gabi Martin 
Published: April 2003

AbstractThis actual extension of our previous work demonstrates the strong interaction of cavitation inside injection nozzles with the external jet flow. Due to the high sensitivity of cavitation on the imposed initial and boundary conditions, simulations with restriction to the internal nozzle flow are qualitatively and quantitatively incorrect. Results of this very first simulations indicate the potential of cavitation for enhancement of atomization and spray formation.
Material Modelling of Porous Media for Wave Propagation Problems
Authors: Schanz M. 
Published: April 2003

AbstractUnder the assumption of a linear geometry description and linear constitutive equations, the governing equations are derived for two poroelastic theories, Biot's theory and Theory of Porous Media (TPM), using solid displacements and pore pressure as unknowns. In both theories, this is only possible in the Laplace domain. Comparing the sets of differential equations of Biot's theory and of TPM, they show different constant coefficients but the same structure of coupled differential equations. Identifying these coefficients with the material data and correlating them leads to the known problem with Biot's ‘apparent mass density’. Further, in trying to find a correlation between Biot's stress coefficient to parameters used in TPM yet unsolved inconsistencies are found. For studying the numerical effect of these differences, wave propagation results of a one‐dimensional poroelastic column are analysed. Differences between both theories are resolved only for compressible constituents.
On the properties of the radiosity equation near corners
Authors: Hansen Olaf 
Published: April 2003

AbstractThe radiosity equation is an integral equation of the second kind which describes the energy exchange by radiation between surfaces in R3. It is assumed that all surfaces are Lambertian reflectors and that all emitters are diffusive emitters. The radiosity equation plays an important role for the calculation of photo realistic images with the help of computers. Many surfaces which are used in practical calculations are only piecewise smooth and contain edges or corners. In this contribution we present regularity results for the solution of the radiosity equation in the vicinity of corners. The space of piecewise continuous functions is not suitable for this equation and we construct a new function space which contains the solution of the radiosity equation.
Numerical simulation of rotational symmetric tube bulging with inside pressure and axial compression
Authors: Kosel F. , Pipan J. , Petrišič J. 
Published: April 2003

AbstractThe contribution treats the process of rotational symmetric tube bulging with inside pressure and axial compression. This process enables the standard tubes to be formed into different rotational symmetric hollow parts in such a way that their central part is expanded into a desired shape while the ends remain unchanged. The superposition of axial compression contributes to a more favourable forming stress state, which is reflected in larger forming limits and smaller wall thinning in the widened area. The problems characterizing the process are a limited range of compression stability and difficulties met when establishing and optimizing the technological parameters of the process whose course cannot be defined in an analytical way. Based on a physical model of the forming process, a numerical model was built. Using ABAQUS code the model was simulated over the entire stress/forming region. A comparison of the computer simulated forming process with the experimentally obtained results showed that the model was highly accurate.
Homogenization of Fatigue and Creep Durability of Composites
Authors: Mikhailov S.E. , Orlik J. 
Published: April 2003

AbstractThe paper is an extension of the theory presented in [4] to fatigue, creep and other types of time‐dependent material behaviour. In the previous paper a multi‐phase periodic composite subjected to prescribed mechanical loads was considered. The asymptotic homogenization was applied for calculation of homogenized macro‐stresses. A nonlocal approximate macro‐strength condition, defined on homogenised stress‐field, was derived from the micro‐strength conditions and their convergence to the approximate macro‐strength condition, as the structure period tends to zero, was proved. This paper presents the analogous results for the macro‐durability of elastic and viscoelastic composites.
Autonomy, Controllability, and Extension Modules
Authors: Zerz Eva 
Published: April 2003

AbstractThe so‐called behavioral approach to systems theory, developed by Willems, provides a unified framework for the mathematical treatment of linear systems. In the behavioral context, a linear system is nothing but the solution space of a linear system of (partial) difference or differential equations. For simplicity, the coefficients are supposed to be constant.Oberst proved a duality theorem that builds upon an earlier result of Palamodov. It says that for certain signal spaces of interest, e.g., the smooth functions or the distributions, the solutions spaces of linear systems of partial differential equations, are dual to certain polynomial modules associated to them. Then the solution space and the module contain the same information, and algebraic properties of the module translate to analytic properties of the solution space. Powerful tools from commutative algebra may be used to derive them.As a prominent example, we study two properties that lie at the very heart of systems and control theory: autonomy and controllability. We summarize the characterizations given by several authors, and unify them in the language of extension modules, an algebraic concept which yields a full classification of these systems theoretic notions.
Chances and limitations of a short‐term overreaction effect – stochastic considerations and empirical results
Authors: Düvelmeyer D. , Hofmann B. 
Published: April 2003

AbstractAs a specific case of the overreaction phenomenon in financial markets we observe reversals of index and future prices in periods following a suggested “qualified movement” of prices. Such a situation is indicated on the one hand by a monotone growth or decline of closing prices during three trading days. On the other hand, there are formulated stochastic conditions expressing a sufficiently improbable market situation, which is frequently compensated by a significant short‐term price reversal. Reversal measures are discussed and a case study completes the paper.
On Existence Theorems for Solutions of Non‐Linear Systems
Authors: Mayer Jan 
Published: April 2003

AbstractAn equivalent formulation of a recent result in [1] states that if the conditions of the Theorem of Newton‐Kantorovich are satisfied in a slightly modified (but equivalent) form in the maximum norm for a function g : G → ℝn, G ⊆ ℝn, guaranteeing the existence of a zero in D, then the conditions of Miranda's Theorem are automatically satisfied. We prove that this result holds for arbitrary norms if the conditions of the Theorem of Newton‐Kantorovich are suitable strengthened and Miranda's Theorem is suitably generalized.
Multi‐grid for PDEs on complicated domains
Authors: Frauböse N. , Sauter S.A. 
Published: April 2003

AbstractA multi‐grid method for solving linear equation systems as they arise from finite element discretisations of elliptic boundary value problems on complicated domains will be presented and analysed. The emphasis is on the robustness of this algorithm with respect to the geometric details in the domain. Robust multi‐grid convergence can be proved for a two‐dimensional model problem.
Formulation of a Non‐linear Higher‐Order Shell Theory Using the Convective Description
Authors: Sparr H. , Ulbricht V. 
Published: April 2003

AbstractBy formulating a higher‐order non‐linear shell theory, we start with the basic equations of continuum mechanics of a three‐dimensional body. By assuming a director set on a reference surface of a shell, the description shifts into the shell space. The position vector for the body is introduced as a power series with respect to the out‐of‐surface variable. By considering more than the usual linear part of the series, the complete three‐dimensional strain tensor is available. The motion of the continuum can be represented through the usage of the convective description which combines properties from both the spatial and the material description. Furthermore, the rate‐type formulation gives the opportunity to deal with geometrical nonlinearities in a three‐dimensional field problem efficiently. Following these two concepts results as well in a position‐dependent as in a time‐dependent base vector set; applying them leads to an initial boundary value problem (IBVP).
Improved sensitivity of biomolecular interaction analysis mass spectrometry for the identification of interacting molecules
Authors: Lopez Frédéric , Pichereaux Carole , Burlet‐Schiltz Odile , Pradayrol Lucien , Monsarrat Bernard , Estève Jean‐Pierre 
Published: April 2003

AbstractBiological functions of most macromolecules depend on their ability to interact with other molecules and a great challenge is the complete description of the protein interaction networks. Biomolecular interaction analysis (BIA) is an optical technology that uses the surface plasmon resonance phenomenon for characterizing macromolecular interactions between an analyte in solution and its ligand immobilized on a sensor chip. Further identification of interacting proteins can be achieved by combining this nondestructive method to mass spectrometry (MS). The BIA‐MS approach represents a promising tool in proteomics for the characterization of protein/protein interactions. In this study, we report on the improved sensitivity in the identification of an unknown protein bound to a known ligand by a rapid and simple BIA‐MS approach. We took advantage of a new automatic and very reproducible microelution procedure available on BIACORE 3000 instruments, called “microrecovery”, to elute the bound protein from the sensor chip. Protein identification was then achieved after tryptic digestion by matrix‐assisted laser desorption/ionization‐time of flight mass mapping and database search. The strategy was succesfully applied to the model protein SHP2 tyrosine phosphatase interacting with an immunoreceptor tyrosine‐based inhibitory motif sequence of the sst2 somatostatin receptor. Optimization of the BIA‐MS approach allowed the unambiguous identification of 10–20 fmol of the protein specifically trapped from a complex mixture of cytosolic extracts.
Identification of the human salivary cystatin complex by the coupling of high‐performance liquid chromatography and ion‐trap mass spectrometry
Authors: Lupi Alessandro , Messana Irene , Denotti Gloria , Schininà Maria Eugenia , Gambarini Gianluca , Fadda Maria Benedetta , Vitali Alberto , Cabras Tiziana , Piras Vincenzo , Patamia Maria , Cordaro Massimo , Giardina Bruno , Castagnola Massimo 
Published: April 2003

AbstractHuman salivary cystatins, five major (S, S1, S2, SA, SN) and two minor (C and D), are multifunctional proteins playing a different role in the oral environment. Salivary cystatin SN is able to effectively inhibit lysosomal cathepsins B, C, H and L and cystatin SA inhibits cathepsins C and L in vitro. These activities suggest, particularly for cystatin SN, an important role in the control of proteolytic events in vivo. Differently, cystatins S are involved, together with statherin, in the mineral balance of the tooth. Due to their distinct role, a reliable method for identification and quantification of the different cystatins, as well as of possible truncated and derived forms, could be helpful for the assessment of the status of the oral cavity. To this purpose high‐performance liquid chromatography electrospray ionization mass spectrometry (HPLC‐ESI MS) was applied to the analysis of human saliva obtained from healthy subjects. All known salivary cystatins, with the exception of cystatin C, were detected. Strong evidence was also obtained for the presence in saliva of post‐translational modified isoforms of cystatins, which may be related to donor habits. Cystatin SN and cystatins S, S1 and S2 were well separated by HPLC‐ESI MS coupling from other components and thus this approach can be successfully applied to their quantification.
Proteomics approach to identify wound‐response related proteins from rice leaf sheath
Authors: Shen Shihua , Jing Yuxiang , Kuang Tingyun 
Published: April 2003

AbstractIn order to avoid the complex conditions of the intact plant for simple analysis of proteins in wound‐response stress, we used the detached rice leaf sheath which is a very active part of the rice seedling. Proteins were extracted from rice leaf sheath at 0, 12, 24, 48 h after cutting and separated by two‐dimensional (2‐D) polyacrylamide gel electrophoresis. Changes in differentially displayed proteins were found in leaf sheaths after cutting in the 0–48 h time course. Ten proteins were up‐regulated, while 19 proteins were down‐regulated compared with those on the four 2‐D gels. Among them, 14 proteins were analyzed by N‐terminal, or internal amino acid sequence. The clear functions of nine proteins could be identified. Six proteins did not yield amino acid sequence information due to their blocked N‐termini. Furthermore, 11 proteins were determined by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry, and identified protein database matching. It was shown that the down‐regulated proteins were calreticulin (nos. 5, 6), histone H1 (no. 15) and hemoglobin (no. 17), putative peroxidase (no. 19); the up‐regulated proteins were Bowman‐Birk trypsin inhibitor (no. 23), putative receptor‐like protein kinase (nos. 24, 25), calmodulin‐related protein (no. 26), small subunit of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (no. 27), mannose‐binding rice lectin (nos. 28, 29). Among all the above proteins, four (nos. 23, 24, 25, 26) have been confirmed to be wound‐response proteins. The others cannot be excluded as also being related to wound‐responses, such as the signal transduction‐related proteins (nos. 5, 6), photosynthesis‐related protein (no. 27), and stress‐response proteins (nos. 19, 28, 29). This is the first time protein changes in response to wounding in rice leaf sheath have been shown.
Guide for the Practical Application of the ICRP Human Respiratory Tract Model
Authors: Valentin J. 
Published: April 2003

The ICRP Publication 66 Human Respiratory Tract Model for Radiological Protection (HRTM) has been applied to calculate dose coefficients (doses per unit intake) and bioassay functions in ICRP Publications 68, 71, 72 and 78. For these purposes, ICRP assigned numerical values to a range of model parameters, such as the size of the inhaled particles and the breathing rate of the subjects. These are known as ‘default’ or ‘reference’ values, and were chosen to be typical, representative values. In any particular situation the actual values of many parameters can be considerably different from the reference values. Usually, doses from intakes of radionuclides are low compared with the relevant limit or constraint, and the resulting difference is unimportant. There are, however, circumstances where more reliable assessments of intake and dose are desirable. This Guidance Document therefore gives advice on applying specific information within the framework of the HRTM for assessing occupational and environmental exposures and for interpreting bioassay data. Chapters on each aspect of the model (morphometry, physiology, deposition, clearance, gases and vapours, dosimetry) provide: A summary of how the HRTM treats that topic; Information on the reference values of relevant parameters; Guidance on choosing between default values; Information on how doses and bioassay quantities (lung retention, urine, and faecal excretion) vary with the values of selected parameters, giving guidance on the importance of obtaining specific information; Simple examples of the use of specific information relating to the topic. Annexes give additional information for those directly involved in applying the HRTM to specific situations, including guidance on obtaining parameter values. A brief overview is given of the deposition, characterisation, and sampling of aerosols, with references to further information, as there are relevant text books already available. Issues specific to radioactive aerosols, such as low particle number concentrations for high specific activity materials are, however, addressed. Guidance on obtaining information about absorption of inhaled radionuclides into blood is given in greater detail, because this is a topic on which ICRP has traditionally given guidance, and because a compilation of such information is not readily available elsewhere. Several detailed examples are also provided. One involves assessment of an individual's intake and committed dose from comprehensive bioassay monitoring data. The others deal with the derivation of HRTM absorption parameter values from experimental data, and their application, with additional information on e.g. size distribution, to calculate dose coefficients and interpret bioassay data.
Spatio‐temporal expression of Drosophila mitochondrial transcription factor A during development
Authors: Takata Kei‐ichi , Inoue Yoshihiro H. , Hirose Fumiko , Murakami Shizuka , Shimanouchi Kaori , Sakimoto Ippei , Sakaguchi Kengo 
Published: April 2003

AbstractWe previously reported cloning of the Drosophila mitochondrial transcription factor A (D‐mtTFA) gene, and characterization of a recombinant protein. In this report, the expression and distribution patterns of D‐mtTFA during development are described. D‐mtTFA mRNA and its protein product were found to be abundant in cells of tissues undergoing both proliferation and polytenization. Furthermore, a DRE‐like sequence present in the D‐mtTFA gene showed promotor activity in Drosophila Kc cells. In addition, D‐mtTFA was detected in brain throughout the developmental process, as well as in non‐proliferating tissues, such as flight muscle and cardia, and was also found in spermatids of imagos. D‐mtTFA possesses a nuclear‐targeting sequence, and is present in the nucleus at the syncytial stage, where bundles of 64 spermatids are present during spermatogenesis. The results suggest that D‐mtTFA not only contributes to the mitochondrial DNA transcription and replication system, but also has a role in cell proliferation and development, including spermatogenesis.
John R. Rickford, African American Vernacular
English: Features, evolution, educational implications.
Malden, MA: Blackwell, 1999. Pp. xxviii, 399.
Authors: Yang James H. 
Published: April 2003

This book primarily addresses the following questions:(a) What are the features of African American Vernacular English
(AAVE), and how is it used?(b) What is its evolution and where is it headed?(c) What are its educational implications?