bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über die klassischen Randwertaufgaben in der Theorie der Wärmespannungen in stückweise stetigen, anisotropen Körpern unter Kopplungsbedingungen
Authors: Beckert H. 
Published: May 2007

AbstractIn der Arbeit werden die klassischen Randwertaufgaben der linearen Thermoelastizitätstheorie für Körper D mit stückweise stetigem elastischen und thermischen Aufbau gelöst und Regularitätsbeweise gegeben. Dabei werden längs der geschlossenen Unstetigkeitsflächen Si = δ Di im Innern des Körpers D = D1 + D2 + … + Ds zugelassen:
Stetiger Durchgang aller Verschiebungskomponenten durch Si
Stetiger Durchgang der Normalkomponenten des Verschiebungsvektors durch Si
Lösung sämtlicher Verheftungsbedingungen längs Si
Ein Wirbelmodell zur Behandlung der Strömung am Rotorblatt eines Hubschraubers
Authors: Isay W. H. 
Published: May 2007

AbstractMit Hilfe der instationären Wirbeltraglinientheorie wird eine Näherungsmethode zur Berechnung der Auftriebsverteilung an Rotorblättern im Vorwärtsflug angegeben. Die vorgelegte Theorie berücksichtigt bezüglich der Wirbelgeometrie einen ungleichförmigen (insbesondere trapezförmigen) Durchfluß durch die Rotorebene sowie den Aufrollvorgang und die Kontraktion der freien Querwirbel. Bei der Ermittlung der Zirkulationsverteilung der Rotorflügel wird insbesondere der Fall behandelt, daß die Blätter die aufgerollten und kontrahierten Spitzen‐ und Nabenwirbel des jeweils vorausfahrenden Flügels durchschlagen.Der Anhang der Arbeit enthält Formeln zur Berechnung des von einem Rotor abgestrahlten (kompressibel zu behandelnden) akustischen Druckfeldes.
Die Versetzungen in der physikalisch nichtlinearen Elastizitätstheorie
Authors: Knésl Z. , Semela F. 
Published: May 2007

AbstractDas Spannungsfeld einer Stufenversetzung und einer Schraubenversetzung wird mit einem speziellen nichtlinearen Ansatz für das Elastizitätsgesetz für ein isotropes, unendlich ausgedehntes Medium berechnet und die Anwendung des Ergebnisses besprochen.
Deformationsgesetze des Modellstruktursystems
Authors: Bergander H. 
Published: May 2007

AbstractDas Modellstruktursystem ist eine Klasse von Deformationsgesetzen, die nach einheitlichen Additionsprinzipien aus drei Elementaroperatoren zwischen Spannung und Dehnung aufgebaut werden und der Beschreibung des rheonomen nichtlinearen Verhaltens von isotropen Werkstoffen im Bereich kleiner Verzerrungen dienen: Es enthält die Deformationsgesetze der nichtlinearen Elastizitätstheorie, der Theorien des plastischen Fließens, des stationären Kriechens und der linearen und nichtlinearen viskoelastischen Nachwirkung mit Exponentialkernen als Sonderfälle. Der besondere Vorzug für die Anwendung besteht in dem einheitlichen Aufbau aller Gesetze als Systeme nichtlinearer Differentialgleichungen erster Ordnung, der für rein viskoelastische Gesetze offensichtlich wird.
Nicht‐rotationssymmetrische Schwingungen beliebig dicker Kreiszylinderschalen
Authors: Zimmermann P. 
Published: May 2007

AbstractDie Grundgleichungen der linearen Elastokinetik liefern Verschiebungsvektor, Verzerrungs‐ und Spannungstensor der ungedämpften, harmonischen, nicht‐rotationssymmetrischen Schwingungen kreiszylindrisch begrenzter Kontinua. Für die an den Mantelflächen spannungsfreie, beliebig dicke aber i. a. unbegrenzt lange Zylinderschale werden Eigenwertgleichungen und die Feldgrößen der freien Schwingungen ermittelt. Davon ausgehend erhält man durch Grenzübergänge die entsprechenden Größen der infinitesimal dünnen Zylindermembran. Die Eigenwerte sind für Querkontraktionszahlen 0 ≦ ν ≦ 0,5 und Radienverhältnisse 0 ≦ β ≦ 1 numerisch ermittelt worden und hier teilweise graphisch wiedergegeben.
Störungsrechnung für lineare gewöhnliche Differentialoperatoren Teil II
Authors: Schmidt A. 
Published: May 2007

AbstractEs wird auf direktem Wege gezeigt, daß alle nach Potenzen des Störparameters ε fortschreitenden Reihen, die ein Eigenwertproblem, bestehend aus einem System linearer gestörter Differentialgleichungen und Randbedingungen, formal erfüllen, auch konvergieren und das Problem lösen.
Zur Elastizitätstheorie des dreidimensionalen, dehnsteifen Punkthaufens
Authors: Schade D. 
Published: May 2007

AbstractEs wird die Elastizitätstheorie des Quader‐ und Tetraeder‐Punkthaufens vorgestellt. An Beispielen wird gezeigt, daß es Anwendungen der Theorie des Punkthaufens in der Methode der finiten Elemente gibt.
On the interpretation of structural damping
Authors: Rösel R. 
Published: May 2007

AbstractThe usual definition of structural damping leads naturally to a complex differential equation of motion, the interpretation of the complex solution of which has caused some confusion in the literature. Even a real equation obtained by a straightforward method does not prove to be satisfactory. For this reason, a new principle is introduced, that of “accompanying”, virtual motion; the resulting equation and solution are still such as one would expect, but the interpretation becomes physically straightforward and mathematically coherent. This is shown first (for single degree of freedom) for the homogeneous equation, to illustrate a case of non‐periodic motion; then, also introducing an “accompanying”, virtual force, the inhomogeneous equation is solved. Finally, the generalization to several degrees of freedom is indicated, and the implications of the method are illustrated by the typical case of aerodynamic flutter.
Convergence of Huber's method for heat conduction problems with change of phase
Authors: Fasano A. , Primicerio M. 
Published: May 2007

AbstractIn diesem Artikel wird die Konvergenz einer Methode zur Lösung einer Wärmeleitungsaufgabe mit Phasenübergang bewiesen. Die Methode scheint einige bedeutungsvolle numerische Vorteile zu bieten. Es wird eine α‐priori Fehlerabschätzung gegeben.
The Turbulent EMF u′ × B′ in the Case of Non‐Vanishing Mean Flow
Authors: Krause F. 
Published: May 2007

AbstractA more convenient formula (c. f. [2]) for the turbulent mean electromotive force u' × B' in the presence of a nonvanishing mean flow is derived by slightly modifying the representation ([2], [3]) of the Green's tensor Gij of the induction equation for velocity fields with constant rate of strain. Furthermore the existence of growing dynamo solutions of the induction equation of the mean field is analysed under the assumption that there is a linear relation with constant coefficients connecting the turbulent emf and the mean magnetic field.
The Axisymmetric Boussinesq Problem for a Radiating Heated Punch
Authors: Chakrabarti S. 
Published: May 2007

AbstractThe solution of the axisymmetric heated punch problem when the heat flow is prescribed on a finite part of the boundary, the remainder radiating in accordance with Newton's law is obtained. The temperature, displacement and stresses have been evaluated. The results show appreciable differences with the cases when radiation is neglected.
Long Time Behavior of a Decaying Vortex
Authors: Gunzburger M. D. 
Published: May 2007

AbstractThe motion and decay of a vortex submerged in a two‐dimensional inviscid stream is considered with view of seeking solutions valid for all time. A multiple time scale perturbation scheme is used to obtain solutions. The important effects of viscosity near the center of the vortex are included by a systematic procedure. To illustrate the theory solutions are then presented for the motion of a vortex subject to a sudden uniform gust and for the motion of a vortex in the presence of a wall.
Ein neues Variationsprinzip mit Anwendung auf Schwingungen flacher Schalen nach der Methode der finiten Elemente
Authors: Tabarrok B. , Gass N. 
Published: May 2007

AbstractEin finites Element für die Schwingungsanalyse flacher Schalen wurde formuliert. Die Entwicklung der Elementgleichungen basiert auf einem zweifeldrigen Variationsprinzip. Innerhalb des Elementes wird ein Impulsfeld angenommen, am Rand ein Geschwindigkeitsfeld. Die Extremalbedingungen des Funktionals sichern a) die Befriedigung der Kompatibilität innerhalb des Elementes, b) die Anpassung des hergeleiteten Geschwindigkeitsfeldes innerhalb des Elementes mit dem angenommenen Feld am Rand und c) die Gleichgewichtsbedingungen entlang der Ränder der Elemente. Die wichtigsten Elementmatrizen sind in expliziter Form angegeben. Verschiedene Beispiele wurden analysiert und dabei die Wirkungsweise des Verfahrens aufgezeigt.
Asymptotische Näherungen der modifizierten Mathieuschen Funktionen für komplexe Eigenwertparameter h = |h| (1 ±; j)/√2
Authors: Rembold B. 
Published: May 2007

AbstractZur Berechnung der Übertragungseigenschaften von verlustbehafteten Leitungen mit elliptischem Querschnitt werden in Weiterführung einer Arbeit von Piefke asymptotische Näherungen der modifizierten Mathieuschen Funktionen für große komplexe Eigenwertparameter h = |h| (1 ± j)/√2 hergeleitet. Die Ergebnisse werden in einigen Bildern mit den exakten Funktionen verglichen.
Lineare elliptische Zustände mit nichtlinearem Zielfunktional
Authors: Miersemann E. 
Published: May 2007

AbstractWir untersuchen elliptische Zustände, die durch das Dirichletproblem gegeben sind. Das Zielfunktional ist ein allgemeiner nichtlinearer Ausdruck. Wir zeigen die Existenz der optimalen Steuerung. Für eine spezielle beschränkte Steuerungsmenge beweisen wir die Regularität der optimalen Steuerung.
Geometrically Nonlinear Shell Theory in the Light of the Method of Asymptotic Integration
Authors: Novotný B. 
Published: May 2007

AbstractDie in der Arbeit beschriebene Methode der asymptotischen Integration gestattet ein iteratives Vorgehen zur sukzessiven Bestimmung einer Näherungslösung der dreidimensionalen Gleichungen der geometrisch nichtlinearen Schalentheorie. Es wird eine Klassifikation der Schalenprobleme in Ausdrücken qualitativer und quantitativer Charakteristiken der Schalendaten dargeboten und auf eine Möglichkeit hingewiesen, den Einfluß verschiedener Typen von äußeren Einwirkungen abzuschätzen. Auf der durch die asymptotische Analysis gewonnenen Grundlage kann eine allgemeine Information über das Verhalten der Schale abgeleitet werden. Für gewisse Beispiele von Platten und Schalen werden die auf diesem Wege gemachten Voraussetzungen mit numerischen Ergebnissen verglichen.
Thermodynamische Analyse von Deformationsgesetzen des Modellstruktursystems
Authors: Balke Herbert 
Published: May 2007

AbstractEs werden die Eigenschaften der Verzerrungsarbeit untersucht, die mit Hilfe nichtlinear‐rheonomer Deformationsgesetze berechnet wurde. Durch Einführung einer wegabhängigen Viskosität wird gezeigt, daß die verwendeten Deformationsgesetze thermodynamisch zulässig sind.
Der Einfluß der Machzahl auf wellenwiderstandsoptimierte Rümpfe und Profile bei Überschallanströmung
Authors: Wellmann J. 
Published: May 2007

AbstractDie nach der Theorie schlanker Körper berechneten Konturen mit minimalem Wellenwiderstand zeigen keine Abhängigkeit von der Machzahl, wohingegen einige nichtlineare Optimierungen einen derartigen Einfluß aufweisen. Ausgehend von einer widerspruchsfreien Linearisierung der Erhaltungssätze wird eine geschlossene lineare Theorie angegeben, in der die Optimierung von Rotationskörpern exakt und explizit möglich ist. Die durch die Stromfunktion dargestellten Konturen enthalten die alten Lösungen als asymptotische Sonderfälle und sind auch für höhere Machzahlen gültig.
Investigation of Microwave Absorption of Surface-State Electrons on Liquid 3He
Authors: Konstantinov Denis , Isshiki Hanako , Akimoto Hikota , Shirahama Keiya , Kono Kimitoshi 
Published: May 2007

Abstract
We report on the experimental study of the resonance microwave absorption of surface-state electrons (SSE) on liquid 3He. The absorption is detected as a variation of the microwave power passing through the experimental cell, or as a resonance-induced change in the electron conductivity. In the latter method a decrease of the conductivity is observed, which points out on the possibility of substantial heating of the electrons by the absorbed microwave power. In a vapor-atom scattering regime the temperature dependence of the linewidth agrees well with the theoretical model, and the absolute value of the measured linewidth is about twice larger than the theoretical one. At very high microwave power the side band absorption peaks are observed.
Results after surgical treatment of thumb duplication: A retrospective review of 33 thumbs
Authors: Maillet Marie , Fron Damien , Martinot-Duquennoy Véronique , Herbaux Bernard 
Published: May 2007

Purpose Purpose This study reports the results of surgical treatment of thumb duplication in the Clinique d'Orthopédie et de Chirurgie de l'Enfant de l'Hôpital Jeanne de Flandre in Lille (France). Methods Thirty patients (33 thumbs) operated on between 1995 and 2003 are clinically reviewed. Results The mean postoperative follow-up was 3 years and 11 months. According to Wassel's classification, the series included 12 type II duplications, two type III, 14 type IV, two type V, one type VI and two type VII. The surgical approaches consisted of simple resection of the most hypoplastic thumb (16 thumbs), the Bilhaut–Cloquet procedure (ten thumbs) and resection associated with reconstructive surgery (seven thumbs). The Bilhaut–Cloquet procedure was used in three cases for treatment of type IV duplication On the basis of the Tada scoring system, we obtained 24 good results, eight fair results and one poor result. Conclusion Based on our results, we recommend that the Bilhaut–Cloquet procedure be used not only for the treatment of type II duplication when the thumbs are both hypoplastic and symmetric but also for type IV duplication with the same clinical parameters. For the other types of duplications, we consider that resection of the most hypoplastic thumb associated with reconstructive surgery is the best surgical approach. For type VII duplication, ablation of the triphalangeal thumb remains the best option. We do not recommend osteotomy at the first surgery.
OBESITY AND TIME PREFERENCE: THE HEALTH CONSEQUENCES OF DISCOUNTING THE FUTURE
Authors: ZHANG LEI , RASHAD INAS 
Published: May 2007

SummaryMuch focus has been placed on the obesity epidemic due to its high prevalence and the costs it imposes on society. Using 2004 data from the Roper Center, complemented with 2003 data from the Behavioural Risk Factor Surveillance System, this study analyses the possible effect that time preference has on health in the United States, as measured by the body mass index. After controlling for a variety of covariates and correcting for potential selectivity, some evidence of a positive association between time preference for the present and the body mass index can be found, particularly for males. Research in this area has policy implications in terms of creating incentives for those who lack self-control through the use of pre-commitment devices. Measures addressing self-control issues may be more effective in reducing the rising obesity rates across the world.
Impact of different pH thresholds for 24-hour dual probe pH monitoring in patients with suspected laryngopharyngeal reflux
Authors: Reichel O , Issing W J 
Published: May 2007

AbstractObjectives:The gold standard test for laryngopharyngeal reflux is 24-hour pH monitoring, which determines the reflux area index with a pH threshold of less than four (i.e. the reflux area index four). However, refluxed pepsin is able to cause laryngeal injury at pH levels above five.Study design:Prospective study.Materials and methods:In order to establish normative values for a reflux area index with a pH threshold of less than five (i.e. the reflux area index five), 29 healthy volunteers underwent pH monitoring. In 45 patients with suspected laryngopharyngeal reflux, reflux area index four and reflux area index five were determined by pH study.Results:In healthy volunteers, the reflux area index five was 72.6 (95th percentile). In 29 of 44 patients, laryngopharyngeal reflux was diagnosed due to a reflux area index four of greater than 6.3. However, the reflux area index five revealed laryngopharyngeal reflux in six more patients.Conclusions:For exact analysis of pH monitoring results, two pH thresholds (less than four and less than five) must be considered. Further studies with a larger number of healthy volunteers are necessary in order to reveal normative values for the reflux area index five parameter.
Kernel theorems in spaces of tempered generalized functions
Authors: DELCROIX ANTOINE 
Published: May 2007

AbstractIn analogy to the classical isomorphism between $\mathcal{Lgrave;}(\mathcal{S}(\mathbb{R}^{n}),\mathcal{S}^{\prime}(\mathbb{R}^{m})) $ and $\mathcal{S}^{\prime}(\mathbb{R}^{n+m}) $, we show that a large class of moderate linear mappings acting between the space $\mathcal{G}_{\mathcal{S}}(\mathbb{R}^{n}) $ of Colombeau rapidly decreasing generalized functions and the space $\mathcal{G}_{\tau}(\mathbb{R}^{n}) $ of temperate ones admits generalized integral representations, with kernels belonging to $\mathcal{G}_{\tau}(\mathbb{R}^{n+m}) $. Furthermore, this result contains the classical one.
Fefferman-type metrics and the projective geometry of sprays in two
dimensions
Authors: CRAMPIN M. , SAUNDERS D. J. 
Published: May 2007

AbstractA spray is a second-order differential equation field on the slit tangent bundle
of a differentiable manifold, which is homogeneous of degree 1 in the fibre
coordinates in an appropriate sense; two sprays which are projectively
equivalent have the same base-integral curves up to reparametrization. We show
how, when the base manifold is two-dimensional, to construct from any projective
equivalence class of sprays a conformal class of metrics on a four-dimensional
manifold, of signature (2, 2); the Weyl conformal curvature of these metrics is
simply related to the projective curvature of the sprays, and the geodesics of
the sprays determine null geodesics of the metrics. The metrics in question have
previously been obtained by Nurowski and Sparling (Classical and Quantum Gravity20 (2003) 4995–5016), by a different
method involving the exploitation of a close analogy between the Cartan geometry
of second-order ordinary differential equations and of three-dimensional
Cauchy–Riemann structures. From this perspective the derived metrics
are seen to be analoguous to those defined by Fefferman in the CR theory, and
are therefore said to be of Fefferman type. Our version of the construction
reveals that the Fefferman-type metrics are derivable from the scalar triple
product, both directly in the flat case (which we discuss in some detail) and by
a simple extension in general. There is accordingly in our formulation a very
simple expression for a representative metric of the class in suitable
coordinates.
Antarctic macro-zoobenthic communities: a review and an ecological classification
Authors: Gutt Julian 
Published: May 2007

AbstractA partly new classification of shelf inhabiting Antarctic macro-zoobenthic communities is proposed in this review. The main components are two core communities. One is dominated by sessile suspension feeders supported by food entrained in strong near-bottom currents. Variants of this community include assemblages without sponges, those that prefer sponge spicule mats as substratum and predator-driven systems. The second core community is dominated by the infauna and mobile epifauna and controlled by vertical phytodetritus flux and soft sediments. This community is obviously restricted to areas with low current velocity, particularly in areas that are sheltered due to a heterogeneous coastal and sea floor topography. In addition, in physically controlled shallow water a small number of representatives of all these ecological guilds can become very abundant. Between both core communities a broad range of mixed assemblages exists that can be explained by a gradient in environmental conditions and trophic amensalism. A concept is also proposed for the ecological functioning of systems with extremely low abundances within ecological guilds, such as those that occur under and close to ice shelves, which cannot satisfactorily be explained by trophic limitation. These extremely low abundances may result from a shift during ontogenesis from a state with predominantly mismatched environmental conditions and ecological demands of young recruits, to a state where a match occurs.
Antarctic marine biology – two centuries of research
Authors: Hempel Gotthilf 
Published: May 2007

AbstractWhilst interest in the economic exploitation of the Southern Ocean resources dates back to the last part of the 18th century scientific research into elements of the marine ecosystem only began in the mid 19th century. As far as plankton and benthos are concerned the great exploratory voyages and expeditions laid a firm taxonomic foundation on which later work was built. The most outstanding expedition contribution was from the Discovery Investigations. Concern about uncontrolled exploitation stimulated the SCAR BIOMASS programme which in turn led to CCAMLR with its modelling programmes and top predator monitoring. Recent research on pack ice communities has been aided by dedicated ice-capable research vessels whilst unmanned photographic techniques as well as SCUBA diving and experimental research facilities in the Antarctic have encouraged major research on benthos. International collaboration, interdisciplinary research and good ideas suggest Antarctic marine biology has a bright future.
Learning about Antarctic krill from the fishery
Authors: Kawaguchi So , Nicol Stephen 
Published: May 2007

AbstractAntarctic krill has been studied for many decades, but we are still long way from understanding their biology to be able to make reliable predictions about the reaction of their populations to environmental change. This is partly due to certain difficulties in relation to logistics, operations and survey design associated with scientific surveys that have been obstacles for us to better understand krill biology. The krill fishery is the largest fishery in the Southern Ocean, continuously operating since early 1970s. Recent studies revealed its potential to be used as a unique source for scientific discussions to understand krill biology. In this paper, after a brief overview of krill fishery operation and krill biology, we examine how current data collection through the fishery operation could contribute to a greater understanding of krill biology, and then suggest future priorities for fisheries-related research in relation to recent changes in the Southern Ocean environment.
First evidence for a bipolar distribution of dominant freshwater lake bacterioplankton
Authors: Pearce David A. , Cockell Charles S. , Lindström Eva S. , Tranvik Lars J. 
Published: May 2007

AbstractAs a result of the recent application of DNA based technology to the investigation of maritime Antarctic freshwater lakes, patterns have begun to emerge in the bacterioplankton communities that dominate these systems. In this study, the bacterioplankton communities of five Antarctic and five Arctic freshwater lakes were assessed and compared with existing data in the literature, to determine whether emerging patterns in Antarctic lakes also applied to Arctic systems. Such a bipolar comparison is particularly timely, given the current interest in biogeography, the global distribution of microorganisms and the controversy over the global ubiquity hypothesis. In addition, it has recently been discovered that commonly encountered bacterial sequences, often originating from uncultivated bacteria obtained on different continents, form coherent phylogenetic freshwater clusters. In this study we encountered both identical sequences and sequences with a high degree of similarity among the bacterioplankton in lake water from both poles. In addition, Arctic freshwater lakes appeared to be dominated by some of the same groups of bacterioplankton thought to be dominant in Antarctic lakes, the vast majority of which represented uncultivated groups.