bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über die Sensibilität von Eigenwerten und Eigenvektoren
Authors: Kuhnert F 
Published: May 2007

AbstractBetrachtet werden allgemeine Eigenwertaufgaben mit parameterabhängigen Matrizen. Sensibilitätsanalyse bedeutet Untersuchung des Einflusses dieser Parameter auf die Eigendaten. Für die Eigenwerte werden lineare und quadratische Glieder angegeben. Untersucht werden auch iterative Verfahren für inverse Aufgaben, die entstehen, wenn einzelne Eigenwerte vorgegeben werden und die entsprechenden Parameter zu identifizieren sind.
Über die Lösung des St.‐Venantschen Torsionsproblems durch singuläre Randintegralgleichungen
Authors: Zlatanovski T. 
Published: May 2007

AbstractSinguläre Integralgleichungen wurden bislang fast nicht zur Lösung des klassischen St.‐Venantschen Torsionsproblems angewandt. In dieser Arbeit wird das Problem auf direkte Weise in eine singuläre Randintegralgleichung überführt, und dann werden die Bedingungen zu deren eindeutiger Lösung (auch im Falle mehrfach zusammenhängender Stabquerschnitte) angegeben. An einem Beispiel wird gezeigt, daß diese singuläre Randintegralgleichung in manchen Fällen auch zur exakten analytischen Lösung des Torsionsproblems gut geeignet ist.
A Finite‐Rotation Theory for Elastic‐Plastic Shells under Consideration of Shear Deformations
Authors: Bašar Y. , Weichert D. 
Published: May 2007

AbstractA consistent, five‐parametric shell theory which permits the consideration of transversal shear deformations is developed for elastic‐plastic analysis of shells undergoing finite rotations. The constitutive equations derived allow the consideration of isotropic and kinematic hardening with temperature dependent yield limit and deliver as special case the Prandtl‐Reuss equations. For the application of incremental‐iterative solution strategies, the field equations, in particular, the principle of virtual work are transformed into incremental equations. The constitutive relations are given in terms of stresses rather than of the two‐dimensional force variables and present, thus, a suitable basis for the development of layered numerical models.
Zur numerischen Integration linearer zeitvarianter Systeme
Authors: Bergmann K. 
Published: May 2007

AbstractEs werden 1‐ und 2‐stufige Runge‐Kutta‐Verfahren vom Gauß‐Typ vorgestellt, die speziell auf lineare zeitvariante Bewegungsgleichungssysteme zugeschnitten sind. Gegenüber anderen Algorithmen, die in diesem Zusammenhang angewendet werden, arbeiten sie theoretisch schneller, da ihr Rechenaufwand kleiner ist und sie absolut stabil sind.
Globale Stabilität und Umlauflösungen für ein System zweier gekoppelter Josephson‐Kontakt‐Gleichungen
Authors: Reitmann V. 
Published: May 2007

AbstractEs wird eine Zwei‐Punkt‐Diskretisierung der gedämpften Sinus‐Gordon‐Gleichung untersucht, welche die Dynamik zweier gekoppelter Josephson‐Kontakte beschreibt. Unter Benutzung von Frequenzmethoden und Vergleichstechniken wird gezeigt, daß Oszillationen (Zyklen erster Art) nicht auftreten können. Es werden Parameterbereiche angegeben, für die Umlauflösungen existieren, und es werden Bedingungen formuliert, bei denen jede Lösung des Systems gegen einen stationären Punkt konvergiert.
On the Stability of an Elastic Imperfect Column Including Axial Compressibility
Authors: Guran A. 
Published: May 2007

AbstractThe nonlinear stability of a compressible elastic imperfect column under uniaxial compression is studied. It is shown that in addition to a stable symmetric bifurcation diagram, hysteresis, and a trifurcation may occur. Using a nonlinear finite element technique, numerical examples illustrating the imperfection sensitivity of an elastic compressible column in various ranges of slenderness ration are given. The present paper sheds new light on the question of the possibility of snap‐through buckling of a compressible column.
Influence of Shear Deformation and Rotatory Inertia on the Solutions of the Generalized Mathews Problem
Authors: Bogacz R. , Krzyżyński T. , Popp K. 
Published: May 2007

AbstractThe influence of shear deformation and rotatory inertia on the dynamics of a beam under a moving harmonic force is studied. Solutions in the whole range of parameters for the shear beam and the Rayleigh beam on elastic foundation are presented. The obtained results are compared with solutions for the Timoshenko beam and the Bernoulli‐Euler beam. The analysis makes it possible to determine separately the influence of shear deformations and rotatory inertia on the solutions of the generalized Mathews problem.
Two General Representation Theorems for Arbitrary‐Order‐Tensor‐Valued Isotropic and Anisotropic Tensor Functions of Vectors and Second Order Tensors
Authors: Xiao H. 
Published: May 2007

AbstractIn this paper, it is shown that irreducible representations for r‐th‐order‐tensor‐valued isotropic or anisotropic tensor functions depending on an arbitrary number of vectors and second order tensors as variables may be formed by the union of irreducible representations for certain r‐th‐order‐tensor‐valued isotropic or anisotropic tensor functions merely depending on not more than three variables (for r ≧ 1) or four variables (for r = 0) and hence that the representation problem for the former may be reduced to that for the latter.
Mixed Convective Conjugate Heat Transfer from a Vertical Flat Plate
Authors: Pop I. , Ingham D. B. , Yuan Y. 
Published: May 2007

AbstractThe aim of this paper is to present a detailed numericla study of the conjugate mixed convection flow along a vertical finite flat plate and both the cases of aiding and opposing flows, which are characterized by the buoyancy parameter λ, are considered. In the first part of the analysis, asymptotic series solutions which are valid near the leading edge of the plate and far from it are given. These solutions are them matched by solving numerically the full governing boundary‐layer equations using a finite‐difference scheme. It is shown that for λ < 0 (opposing flow) the boundary‐layer separates from the plate and we have determined very accurately the location of the point of separation, i.e. where the numerical method breaks down. In addition, an asymptotic expression is given which accurately predicts the position of separation as a function of the buoyancy parameter. Detailed velocity and temperature profiles, and the skin friction and the temperature at the plate are given for a wide range of values of the relevant parameters which occur in the problem.
Bruchbedingungen vom Mohrschen Typ für transversal isotrope Werkstoffe am Beispiel der Faser‐Kunststoff‐Verbunde
Authors: Jeltsch‐Fricker R. 
Published: May 2007

AbstractIn neuerer Zeit sind Kriterien zur Beschreibung des Bruchverhaltens de Matrix von unidirektionalen Faser‐Kunststoff‐Verbunden entwickelt worden, die auf der Mohrschen Bruchhypothese basieren. Die Mohrsche Bruchhypothese besagt in dem betrachteten Fall, daß der Bruchkörper durch seine orthogonale Projektion in einem dreidimensionalen linearen Unterraum des Spannungsraumes festgelegt ist. Die Gestalt des Projektionskörpers liefert damit Vorgaben für die Modellierung von Bruchbedingungen. Mit dem konstruktiven Verfahren zur Bestimmung der zum Bruch Führenden Spannungszustände werden gleichzeitig Richtungen ermittelt, in denen der Bruch auftreten kann.
Free Convection of a Non‐Newtonian Power‐Law Fluid from a Vertical Wavy Surface with Uniform Surface Heat Flux
Authors: Kumari M. , Pop I. , Takhar H. S. 
Published: May 2007

AbstractThe steady laminar free convection in the flow of a non‐Newtonian power‐law fluid along a vertical wavy surface with constant heat flux has been investigated in this paper. The transformed boundary layer equations are solved by using a very efficient implicit finite‐difference method. A sinusoidal surface is used to elucidate the amplitude of the wavy surface effects. Along with the wall temperature, representative velocity and temperature profiles are presented. Numerical results show that the wall temperature decreases as the power‐law index increases, while it increases with the amplitude of the wavy surface. Comparisons with earlier work are also made for a flat plate immersed in a Newtonian fluid. The results are found to compare very well.
On a Mathematical Model of a Radiating, Viscous, Heatconducting Fluid: Remarks on a Paper by J. Förste
Authors: Gergó L. , Stoyan G. 
Published: May 2007

AbstractWe consider a mathematical model of the fluid indicated in the title which is useful in describing several processes of industrial interest like gas flow in lighting devices or flow of molt glass in a glass furnace. This model includes the three‐dimensional Navier‐Stokes equations, mass conservation, and equations for radiation intensity (differential approximation) and temperature.The problem is rewritten to define a weak solution the existence of which we re‐prove following a paper by J. Förste. For unicity of the solution we give a modified proof (under suitable conditions on the solution domain).
Modeling Nonlinear Viscous Incompressible Fluid Flows in Axisymmetric Complex Geometry
Authors: Zarutskaya T. V. 
Published: May 2007

AbstractAn effective approach to solving the problem of steady flow of incompressible nonlinear viscous fluid in arbitrary axisymmetric channels is introduced. We show how to reduce the problem to a variational one, and then how to find the saddle point of an appropriate functional. The relevant techniques are pointed out. We analyse some numerical results.
β‐blocked Multistep Methods for Euler‐Lagrange DAEs: Linear Analysis
Authors: Arévalo C. , Führer C. , Söderlind G. 
Published: May 2007

AbstractMany different methods have been suggested for the numerical solution of index 2 and 3 Euler‐Lagrange equations. We focus on 0‐stability of multistep methods (φ, σ) and investigate the relations between some well‐known computational techniques. By various modifications, referred to as β‐blocking of the σ polynomial, some basic shortcomings of multistep methods may be overcome. This approach is related to projection techniques and has a clear and well‐known analogy in control theory. In particular, it is not necessary to use BDF methods for the solution of high index problems; indeed, “nonstiff” methods may be used for part of the system provided that the state‐space form is nonstiff. We illustrate the techniques and demonstrate the results with a simplified multibody model of a truck.
Effect of Injection on the Squeeze Flow in the Presence of a Magnetic Field
Authors: Usha R. , Sridharan R. 
Published: May 2007

AbstractThe squeeze flow of an electrically conducting fluid between two parallel disks with injection at the lower porous disk in the presence of a magnetic field applied perpendicular to the disk is investigated. Analytic solutions are obtained through the use of a regular perturbation scheme. The results show that the effect of injection is to increase the load carrying capacity in the hydromagnetic squeeze film and this increase is more than that observed without injection.
Proof producing synthesis of arithmetic and cryptographic hardware
Authors: Slind Konrad , Owens Scott , Iyoda Juliano , Gordon Mike 
Published: May 2007

AbstractA compiler from a synthesisable subset of higher order logic to clocked synchronous hardware is described. It is being used to create coprocessors for cryptographic and arithmetic applications. The compiler automatically translates a functionfdefined in higher order logic (typically using recursion) into a device that computesfvia a four-phase handshake circuit. Compilation is by fully automatic proof in the HOL4 system, and generates a correctness theorem for each compiled function. Synthesised circuits can be directly translated to Verilog, and then input to design automation tools. A fully-expansive ‘LCF methodology’ allows users to safely modify and extend the compiler’s theorem proving scripts to add optimisations or to enlarge the synthesisable subset of higher order logic.
Telesurgery: Remote Knowledge Translation in Clinical Surgery
Authors: Anvari Mehran 
Published: May 2007

AbstractDissemination of new surgical knowledge, skills, and techniques across the wide spectrum of practicing surgeons in the community is often difficult and slow. This is even more problematic in countries such as Canada, where geographic distances separate a large portion of community surgeons from the large teaching centers. As an example, the penetration of advanced minimally invasive techniques in Canada has been severely hampered by the inability to provide adequate training opportunities and support for community surgeons, many of whom live in remote regions of the country. In an attempt to overcome the barriers that exist, the Centre for Minimal Access Surgery (CMAS) at McMaster University has been using broadband Internet and telecommunication systems to provide distance training and mentoring to community surgeons living in remote northern communities of Canada. This article describes our experience with telementoring and robot‐assisted remote telepresence surgery and assisting, between a teaching hospital in Hamilton and two community hospitals in northern Ontario and Quebec.
Tumor Localization for Laparoscopic Colorectal Surgery
Authors: Cho Yong Beom , Lee Woo Yong , Yun Hae Ran , Lee Won Suk , Yun Seong Hyeon , Chun Ho‐Kyung 
Published: May 2007

AbstractBackgroundBecause palpating colonic tumors during laparoscopy is impossible, the precise location of a tumor must be identified before operation. The aim of this study was to evaluate the accuracy of various diagnostic methods that are used to localize colorectal tumors and to propose an adequate localization protocol for laparoscopic colorectal surgery.MethodsA total of 310 patients underwent laparoscopy‐assisted colectomy between April 2000 and March 2006. We investigated if the locations of the tumors that were estimated preoperatively were consistent with the actual locations according to the operation.ResultsAll the tumors were correctly localized and resected. Altogether, 203 patients had complete endoscopic reports available. Colonoscopy was inaccurate for tumor localization in 23 cases (11.3%). In total, 104 patients (33.5%) underwent barium enema; five tumors (4.8%) were not visualized, and three tumors were incorrectly localized. Another group of 94 patients (30.3%) underwent computed tomography (CT) colonography, which identified 91 of 94 lesions (96.8%). Finally, 96 patients (31.0%) underwent endoscopic tattooing; 2 patients (2.1%) did not have tattoos visualized laparoscopically and required intraoperative colonoscopy to localize their lesions during resection. Dye spillage was found in six patients intraoperatively, but only one patient experienced clinical symptoms. Intraoperative colonoscopy was performed in four patients; two of the four were followed by endoscopic tattooing, and the other two underwent intraoperative colonoscopy for localization. All lesions were correctly localized by intraoperative colonoscopy. The accuracy of tumor localization was as follows: colonoscopy (180/203, 88.7%), barium enema (97/104, 93.3%), CT colonography (89/94, 94.7%), endoscopic tattooing (94/96, 97.9%), and intraoperative colonoscopy (4/4, 100%).ConclusionsWith a combination of methods, localization of tumors for laparoscopic surgery did not seem very different from that during open surgery. Preoperative endoscopic tattooing is a safe, highly effective method for localization. In the case of tattoo failure, intraoperative colonoscopy can be used for accurate localization.
Effects of Warm Water Sitz Bath on Symptoms in Post‐anal Sphincterotomy in Chronic Anal Fissure—A Randomized and Controlled Study
Authors: Gupta Pravin J. 
Published: May 2007

AbstractBackgroundSitz bath is frequently recommended by physicians for a variety of anal disorders including anal fissure. The aim of the present study was to determine whether sitz bath does have any therapeutic properties improving upon a patient’s postoperative symptoms after a closed lateral sphincterotomy.Materials and MethodsForty‐six patients were randomly assigned to receive analgesics and fiber supplement alone (control patients) or a twice‐daily sitz bath along with identical fiber and analgesics (sitz bath group). A 24‐h pain score—post‐defecation anal burning and symptom improvement—was evaluated on a visual analog scale (VAS).ResultsThe groups were equally matched for age, gender distribution, and duration of disease. No significant difference in mean pain score between groups (p = 0.284) was noticed after one week. However, the patients from the control group experienced significant anal burning compared with patients from sitz bath group (p < 0.0001). The improvement score was higher in the sitz bath group when compared with the control group; however, it did not reached a statistically significant level.ConclusionsPatients after sphincterotomy for anal fissure receiving sitz bath experienced similar levels of pain when compared with those not receiving sitz bath. However, they reported a significant relief in anal burning and a marginally better satisfaction score and no reported adverse side effects.
Stability to oxidation of virgin olive oils as related to olive conditions: Study of polar compounds by chemometric methods
Authors: Evangelisti F. , Zunin P. , Tiscornia E. , Petacchi R. , Drava G. , Lanteri S. 
Published: May 2007

AbstractPolar compounds of virgin olive oils were analyzed. They influence oil flavor and aroma and improve the shelf‐life of the oil. The orthodiphenolic fraction is particularly significant for oil stability because of its antioxidative activity. A relationship between the composition of the whole fraction of polar compounds and the state of health of the olives was established. For this purpose, oil samples were obtained from olives that had reached different degrees of ripeness and that had been affected by Dacus oleae infestation differently. The polar compounds were then analyzed by high‐performance liquid chromatography. The data set was studied by means of chemometric methods. Partial least squares regression was used to obtain models that show a significant correlation between composition of the oil’s polar compounds and conditions of the olives sampled. In particular, compounds with antioxidative activity were directly linked with the state of health of the olives. The models obtained allow tracing of the state of health of the olives sampled through analysis of the polar fraction of virgin olive oil with a high degree of accuracy, and thus prediction of the oil’s expected shelf life.
Development and validation of fluorescence spectroscopic assays to evaluate antioxidant efficacy. Application to metal chelators
Authors: Arora Arti , Strasburg Gale M. 
Published: May 2007

AbstractTwo fluorescence‐based assays were developed for rapid evaluation of compounds for antioxidant activity. These assays were based on the quenching of intensity of the fluorescent probe and an increase in its fluorescence anisotropy due to the free radicals generated during lipid peroxidation. A large unilamellar vesicle system, containing the fluorescence probe diphenylhexatriene‐propionic acid, was used to study the effects of chelators on metal‐ion‐induced lipid peroxidation. In this paper, the actions of the chelating agents ethylenediaminetetraacetic acid disodium salt (EDTA), nitrilotriacetic acid trisodium salt (NTA), adenosine‐5′‐diphosphate disodium salt (ADP), and sodium citrate on Fe(II)‐ and Fe(III)‐induced peroxidation were compared. The effects of chelators on metal‐ion‐induced peroxidation depended on the type of metal used to initiate peroxidation and, for citrate, also on the concentration of chelator used. EDTA strongly suppressed both Fe(II)‐ and Fe(III)‐induced peroxidation in this system. NTA and ADP inhibited Fe(III)‐induced peroxidation but enhanced Fe(II)‐induced peroxidation at all concentrations tested. Citrate promoted both Fe(II)‐ and Fe(III)‐induced peroxidations at lower chelator‐to‐metal ratios; however, at higher ratios, it inhibited both peroxidations. The results of the two fluorescence‐based assays agreed well with the quantitation of conjugated dienes and hydroperoxides by high‐performance liquid chromatography. The combination of sensitivity, speed, and general utility associated with these methods suggests that these methods will be useful in rapid screening of extracts and purified compounds for antioxidant activity.
Quenching mechanism and kinetics of ascorbyl palmitate for the reduction of the photosensitized oxidation of oils
Authors: Lee K. H. , Jung M. Y. , Kim S. Y. 
Published: May 2007

AbstractEffects of 0, 500, 1000, and 1500 ppm (wt/vol) ascorbyl palmitate (AP) on the methylene‐blue‐ and the chlorophyll‐sensitized photooxidations of linoleic acid or soybean oil, either in methanol or in a solvent mixture (benzene/methanol, 4:1, vol/vol), were studied during storage under 3300 lux fluorescent light for 5 h. Steady‐state kinetic approximation was used to determine a quenching mechanism and quenching rate constant of AP in the chlorophyll‐sensitized photooxidation of methyl linoleate in a solvent mixture (benzene/methanol, 4:1, vol/vol). Both methylene blue and chlorophyll greatly increased the photooxidation of linoleic acid and soybean oil, as was expected. AP was extremely effective at minimizing both methylene‐blue‐and chlorophyll‐sensitized photooxidations of linoleic acid and soybean oil, and its effectiveness was concentration‐dependent. The addition of 500, 1000, and 1500 ppm AP resulted in 69.3, 83.6, and 94.6% inhibition of methyleneblue‐sensitized photooxidation of linoleic acid, respectively, after 5‐h storage under fluorescent light. AP showed significantly greater antiphotooxidative activity than α‐tocopherol for the reduction of methylene blue‐sensitized photooxidation of linoleic acid (P < 0.05). The steady‐state kinetic studies indicated that AP quenched singlet oxygen only to minimize the chlorophyll‐sensitized photooxidation of oils. The calculated total quenching rate of AP was 1.0 × 108 M−1s−1. The present results clearly showed, for the first time, the effective singlet oxygen quenching ability of AP for the reduction of photosensitized oxidation of oils.
Collaborative test of determination of iodine value in fish oils. 2. Carbon tetrachloride or cyclohexane/acetic acid as solvents
Authors: Barlow Stuart M. , Bimbo Anthony P. , Miller Eric L. , Thorisson Snorri , Walters D. E. 
Published: May 2007

AbstractNine laboratories participated in a collaborative test to determine the iodine value (IV) of eight samples of fish oil (four with IV<150; four with IV>150) with either carbon tetrachloride (AOCS Official Method Cd 1–25) or cyclohexane/acetic acid (AOCS Recommended Practice Cd 1d‐92) as solvent and 1 h of reaction time. Laboratories received coded duplicate samples (hidden duplicates) and carried out duplicate determinations on each oil by each method (open duplicates). Replacing carbon tetrachloride with cyclohexane/acetic acid resulted in similar mean values for both low‐ and high‐IV oils and similar estimates of repeatability and reproducibility. The repeatability standard deviation (sr), based on hidden duplicates, with carbon tetrachloride and cyclohexane/acetic acid were 1.71 and 1.55, respectively. The corresponding reproducibility standard deviations were 1.81 and 1.98.