bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of Multiphase Flows with Strong Shocks and Density Variations
Authors: Nowakowski Andrzej F. , Jolgam Shaban A. , Ballil Ahmed R. , Nicolleau Franck C.G.A. 
Published: December 2011

AbstractThe system of extended Euler type hyperbolic equations is considered to describe a two‐phase compressible flow. A numerical scheme for computing multi‐component flows is then examined. The numerical approach is based on the mathematical model that considers interfaces between fluids as numerically diffused zones. The hyperbolic problem is tackled using a high resolution HLLC scheme on a fixed Eulerian mesh. The global set of conservative equations (mass, momentum and energy) for each phase is closed with a general two parameters equation of state for each constituent. The performance of various variants of a diffuse interface method is carefully verified against a comprehensive suite of numerical benchmark test cases in one and two space dimensions. The studied benchmark cases are divided into two categories: idealized tests for which exact solutions can be generated and tests for which the equivalent numerical results could be obtained using different approaches. The ability to simulate the Richtmyer‐Meshkov instabilities, which are generated when a shock wave impacts an interface between two different fluids, is considered as a major challenge for the present numerical techniques. The study presents the effect of density ratio of constituent fluids on the resolution of an interface and the ability to simulate Richtmyer‐Meshkov instabilities by various variants of diffuse interface methods. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Analytical Results for the Optimal Control of the quasi‐stationary Radiative Heat Transfer System
Authors: End Thomas 
Published: December 2011

AbstractWe state an optimal control problem of the coupled quasi‐stationary radiative heat equations consisting of the radiative transfer equation and the instationary heat transfer equation that model radiative‐conductive heat transfer. We give an existence and uniqueness result for the state equations and the adjoint equations of the quasi‐stationary radiative heat transfer system. For the optimal control problem the existence of a minimizer is proven. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenization approach for optimal design of perforated layer in acoustic wave propagation
Authors: Rohan Eduard , Lukeš Vladimír 
Published: December 2011

AbstractHomogenization provides a reduced model of the acoustic wave propagation through a periodically perforated layer immersed in an inviscid fluid. The shape of the perforation influences some parameters of the non‐local transmission condition. We developed and implemented numerically the sensitivity analysis for an optimal design of the perforation. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pointwise numerical index determination of unstructured DAEs
Authors: Lamour René 
Published: December 2011

AbstractThe index of a DAE is a measure of the expected difficulties arising when solving it. The tractability index concept determines the index without knowing any solution. It is based on a matrix sequence with matrices of the same dimension as the DAE under consideration. For the numerical realization of the matrix sequence it is advantageous to use so‐called widely orthogonal projectors and to compute derivatives by means of algorithmic differentiation (AD) because of the higher accuracy. The presented method of numerical index determination may become a basic component on the way to a robust index monitor. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of LTI descriptor systems
Authors: Müller Peter C. 
Published: December 2011

AbstractLinear time‐invariant (LTI) descriptor systems Eẋ = Ax + Bu with regular matrix pencils λ(E − A) may be separated by an equivalence transformation into a “slow” and a “fast” subsystem. The consistent solution of the fast subsystem can be presented by the input u and its time‐derivatives. If these time‐derivatives appear explicitly, then the system behaviour is called improper, otherwise it is proper or even strictly proper. This contribution deals with the determination of the related characteristics based on the matrices E, A, B without applying the equivalence transformation: Index k, orders n1, n2 of the subsystems (n1 + n2 = n), (strictly) proper and improper transfer behaviour, degree of improperness of each individual input. These characteristics are calculated by rank conditions of suitable matrices composed of E, A, B. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Segmentation of Stochastic Images using Stochastic Extensions of the Ambrosio‐Tortorelli and the Random Walker Model
Authors: Pätz Torben , Kirby Robert M. , Preusser Tobias 
Published: December 2011

AbstractWe discuss methods based on stochastic PDEs for the segmentation of images with uncertain gray values resulting from measurement errors and noise. Our approach yields a reliable precision estimate for the segmentation result, and it allows us to quantify the robustness of edges in noisy images and under gray value uncertainty. The ansatz space for such images identifies gray values with random variables. For their discretization we utilize generalized polynomial chaos expansions and the generalized spectral decomposition method. This leads to the stochastic generalization of the Ambrosio‐Tortorelli approximation of the Mumford‐Shah functional. Moreover, we present the extension of the random walker segmentation for our stochastic images, which is based on an identification of the graph weights with random variables. We demonstrate the performance of the methods on a data set obtained from a digital camera as well as real medical ultrasound data. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundary triples and quasi boundary triples for elliptic operators
Authors: Behrndt Jussi , Micheler Till 
Published: December 2011

AbstractThe abstract concepts of boundary triples and their recent generalizations are useful tools to parametrize the self‐adjoint and maximal dissipative/maximal accumulative extensions of formally symmetric elliptic differential expressions with the help of explicit boundary conditions. In the present note the parametrizations induced by the “natural” quasi boundary triple with the Dirichlet and Neumann trace as boundary maps are compared with the parametrizations induced by a “classical” ordinary boundary triple, where a regularized Neumann trace is used for one of the boundary maps. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heun und Hamel – Repräsentanten der Mechanik um 1900
Authors: Bremer Hartmut 
Published: December 2011

AbstractZu Beginn des zwanzigsten Jahrhunderts, zu einer Zeit, in der die klassische Mechanik längst als abgeschlossen propagiert wurde, treten KARL HEUN und GEORG HAMEL auf den Plan. Ihnen ist wesentlich der weitere Ausbau der analytischen Mechanik mit zu verdanken, insbesondere im Neuland der nichtholonomen Systeme (HAMELsche Gleichungen, heute meist HAMEL‐BOLTZMANN‐Gleichungen genannt). Es wird gezeigt, welche Auswirkungen ihre Forschertätigkeit auf das zwanzigste Jahrhundert, ja, bis heute hat. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Das Millennium‐Problem der Strömungsmechanik ‐ Lösung der Navier‐Stokes‐Gleichungen
Authors: Krause Egon 
Published: December 2011

AbstractEinleitend werden die Anfänge der im Titel angedeuteten Problematik erörtert. Ausgehend von der Aufnahme in die sieben ungelösten Probleme der Mathematik durch das Clay Mathematics Institute in USA im Jahre 2000 werden frühere enttäuschende Ergebnisse wie das d'Alembertsche Paradoxon und die damals noch nicht lösbaren Euler‐Gleichungen skizziert. Nach der Vorstellung der Navier‐Stokes‐Gleichungen wird die Ableitung der Helmholtzschen Wirbelsätze und der Reynoldsschen Spannungen zur Beschreibung turbulenter Strömungen erörtert. Danach wird die revolutionäre Bedeutung der Prandtlschen Grenzschichttheorie und seiner Traglinientheorie erklärt. Schließlich werden die Einführung numerischer Methoden in die Strömungsmechanik und deren Entwicklung kurz beschrieben. Mit Hilfe von zwei Beispielen wird der heutige Stand der Forschung skizziert. Die Zusammenfassung gibt einen Ausblick auf zukünftige Probleme. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wesentliche Beiträge Österreichs zur Strömungsmechanik bis 1958
Authors: Sockel Helmut 
Published: December 2011

AbstractDas erste Privileg (Patent) für eine Schraube zum Vortrieb eines Schiffes erhielt der als Förster in der Österreichisch‐Ungarischen Monarchie tätige J. Ressel im Jahre 1827. Die Fahrt mit einem Versuchsschiff im Hafen von Triest wurde wegen eines Schadens der Dampfmaschine abgebrochen und konnte nicht wiederholt werden. Der weltweit als Erfinder der nach ihm benannten Wasserturbine bekannte V. Kaplan wirkte an der Technischen Hochschule Brünn 1903‐1934. R. Knoller wurde 1909 an die neu gegründete Lehrkanzel für „Luftschiffahrt und Automobilwesen“ berufen. Seine wesentlichen Beiträge sind der Bau eines aeromechanischen Laboratoriums an der Technischen Hochschule Wien, eines Luftschraubenprüfstandes in Fischamend und zahlreiche Flugzeugkonstruktionen. R. Katzmayr war Leiter dieses Laboratoriums und nach dem Tode Knollers leitete er auch die Lehrkanzel. Er veröffentlichte die „Berichte der Aeromechanischen Versuchsanstalt in Wien“. Nach 1945 kam das aeromechanische Laboratorium zur Lehrkanzel für Strömungslehre, die mit F. Magyar besetzt wurde. Seine wesentlichen Beiträge sind Untersuchungen von Fliehkraftreinigern und Dralldüsen. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational homogenization and parameter‐identification for heterogeneous inelastic materials
Authors: Schmidt Ulrike , Mergheim Julia , Steinmann Paul 
Published: December 2011

AbstractThe aim of this paper is to describe a method for identifying micro material parameters using only macroscopic experimental data. The FE2 method is used to model the behavior of the complex materials with heterogeneous micro‐structure. The resulting least squares problem is minimized using gradient‐based optimization algorithms, where the gradient information is derived analytically within the discretized scheme. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐heating of polymeric laminated composite plates under the resonant vibrations: Theoretical and experimental study
Authors: Katunin A. , Fidali M. 
Published: December 2011

AbstractThe self‐heating effect caused by the energy dissipation during vibration of viscoelastic materials is an important criterion in the evaluation of the structural degradation. In this study the theoretical model of the self‐heating of the polymeric layered FRP plate subjected to the resonant vibration was proposed. The model is based on the complex parameters, which could be obtained in DMA tests. The theoretical model is validated in several experiments. The experiment contains two stages: first, the modal analysis was performed for the evaluation of natural frequencies of vibration and further the specimens were excited to harmonic vibration with their resonant frequencies in the constant strain rate mode. During the second stage the force response and evolution of the temperature distributions on the surface of the specimens were registered. Obtained results allow identifying the self‐heating temperature evolution of the composite and determining the relation of the excitation frequency and self‐heating temperature. Several phenomena observed during the experiments were interpreted following their physical nature. Investigated problem could be applied for predicting the structural life of such composites and in diagnostics and structural health monitoring of the parts and constructions made of polymeric composites. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
The future of catastrophic event prevention: Seven questions leaders need to ask
Authors: Stricoff Scott 
Published: December 2011

AbstractDespite a high level of development, process safety systems are ultimately limited by the organizational cultures that use them. Advancing the effectiveness of catastrophic event prevention will necessarily require changes at the organizational level. Specifically, process safety systems, like personal safety systems before them, must become an integrated part of a whole organizational safety picture, rather than an isolated function of a specialized few. This article poses seven questions that challenge leaders to rethink common assumptions and begin the work of aligning process safety practices with a culture that supports them. © 2011 American Institute of
Chemical Engineers Process Saf Prog, 2011
Design, synthesis, insecticidal activity and structure–activity relationship of 3,3‐dichloro‐2‐propenyloxy‐containing phthalic acid diamide structures
Authors: Feng Mei‐Li , Li Yu‐Feng , Zhu Hong‐Jun , Ni Jue‐Ping , Xi Bin‐Bin , Zhao Liang 
Published: December 2011

AbstractBACKGROUND: Phthalic acid diamide derivatives are among the most important classes of synthetic insecticides. In this study, a 3,3‐dichloro‐2‐propenyloxy group, the essential active group of pyridalyl derivatives, was incorporated into phthalic acid diamide derivatives with the aim of combining the active groups to generate more potent insecticides.RESULTS: Thirty‐one new phthalic acid diamides were obtained, and these were characterised by 1H and 13C NMR. The structure of N2‐[1,1‐dimethyl‐2‐(methoxy)ethyl]‐3‐iodo‐N1‐[4‐(3,3‐dichloro‐2‐propenyloxy)‐3‐(trifluoromethyl)phenyl]‐1,2‐benzenedicarboxamide was determined by X‐ray diffraction crystallography. The insecticidal activities of the compounds against Plutella xylostella were evaluated. The title compounds exhibited excellent larvicidal activities against P. xylostella. Structure‐activity relationships revealed that varying the combination of aliphatic amide and aromatic amide moieties, or the nature and position of substituent Y on the aniline ring, could aid the design of structures with superior performance.CONCLUSION: A series of novel phthalic acid diamides containing a 3,3‐dichloro‐2‐propenyloxy group at the 4‐position of the aniline ring were designed and synthesised. Structure‐activity relationships with the parent structure provided information that could direct further investigation on structure modification. Copyright © 2012 Society of Chemical Industry
Development of a rapid resistance monitoring bioassay for codling moth larvae
Authors: Magalhaes Leonardo C , Van Kretschmar Jaap B , Barlow Vonny M , Roe R Michael , Walgenbach James F 
Published: December 2011

AbstractBACKGROUND: The codling moth, Cydia pomonella (L.), is one of the most important pests of apple worldwide. Use of insecticides for management of this insect has been extensive and has resulted in resistance development. There are a number of different bioassay methods to monitor for codling moth resistance; however, many are not applicable to new insecticides and most are time consuming. A novel 16‐well plasticware bioassay plate containing lyophilized diet was developed for rapid resistance monitoring of codling moth.RESULTS: The contact insecticides acetamiprid and azinphosmethyl were significantly more toxic to neonates than to fourth instars. However, there was no significant difference in LC50 values between neonates and fourth instars to the ingestion insecticides chlorantraniliprole, methoxyfenozide, novaluron and spinetoram. Field colonies of codling moth were significantly more resistant to methoxyfenozide than susceptible populations. A diagnostic dose of 20 µg mL−1 (LC99) was established to monitor for codling moth resistance to methoxyfenozide.CONCLUSIONS: The results presented here demonstrate that a novel and rapid bioassay can be used to monitor for codling moth resistance to methoxyfenozide. The bioassay method is relevant to both ingestion and contact insecticides, but a single diagnostic dose, regardless of larval age, is only relevant to ingestion insecticides. Age‐dependent diagnostic doses are likely necessary for contact insecticides. Copyright © 2011 Society of Chemical Industry
Hydrothermal synthesis and optical properties of hexagonal tungsten oxide nanocrystals assisted by ammonium tartrate
Authors: Pang Hua‐Feng , Xiang Xia , Li Zhi‐Jie , Fu Yong‐Qing , Zu Xiao‐Tao 
Published: December 2011

AbstractCrystals of hexagonal tungsten oxides (hex‐WO3) have been synthesized using hydrothermal method at 150 °C, assisted by the capping reagent of ammonium tartrate (AT). The XRD and EDX results reveal that the lattice distortion exists in all the samples, possibly due to the defects and the intercalation of the residual sodium ions. Different crystal shapes including plate‐like, urchin‐like, and particle structures were obtained by varying concentration of AT and pH values in the precursor solution. Beside the absorption action of the ${\rm NH}_{4}^{ + } $ and Na+ ions, the capping effect can be reinforced by the hydrogen bonding from the tartrate groups in the crystallization process. The bandgap energies were modulated by the size of the nanostructured hex‐WO3 crystals due to quantum confinement effect, which increases from 2.74 to 3.04 eV. Based on the analysis of the photoluminescence and X‐ray photoelectron spectroscopy, the enhancement of the blue emission of the nanocrystals is assigned as a result of a complex of the local intercalation of the residual sodium ions and the oxygen vacancies or defects.
Local piezoelectric response of ZnO nanoparticles embedded in a photosensitive polymer
Authors: Prashanthi K. , Zhang H. , Ramgopal Rao V. , Thundat T. 
Published: December 2011

AbstractLocal piezoelectric properties of ZnO nanoparticles (NPs) embedded in a photo‐epoxy polymer are investigated by piezoresponse force microscopy (PFM). Integrating ZnO NPs into a photosensitive SU‐8 polymer matrix not only retains the highly desired piezoelectric properties of the ZnO, but also preserves photosensitivity and optical transparency of the SU‐8 polymer. These results have strong implications for simple photolithography based low‐cost fabrication of piezoelectric microelectromechanicalsystems (MEMS) and nanoelectromechanicalsystems (NEMS) in both sensing and energy harvesting applications. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distributed containment control of multi‐agent systems with general linear dynamics in the presence of multiple leaders
Authors: Li Zhongkui , Ren Wei , Liu Xiangdong , Fu Mengyin 
Published: December 2011

SUMMARYThis paper considers the containment control problems for both continuous‐time and discrete‐time multi‐agent systems with general linear dynamics under directed communication topologies. Distributed dynamic containment controllers based on the relative outputs of neighboring agents are constructed for both continuous‐time and discrete‐time cases, under which the states of the followers will asymptotically converge to the convex hull formed by those of the leaders if, for each follower, there exists at least one leader that has a directed path to that follower. Sufficient conditions on the existence of these dynamic controllers are given. Static containment controllers relying on the relative states of neighboring agents are also discussed as special cases. Copyright © 2011 John Wiley & Sons, Ltd.
How to protect security and privacy in the IoT: a policy‐based RFID tag management protocol
Authors: Rekleitis Evangelos , Rizomiliotis Panagiotis , Gritzalis Stefanos 
Published: December 2011

ABSTRACTRadio‐frequency identification (RFID) technology constitutes an important part of what has become known as the Internet of Things (IoT) that is accessible and interconnected machines and everyday objects that form a dynamic and complex environment. To secure the IoT in a cost‐efficient manner, we need to build security and privacy into the design of its components. Moreover, mechanisms should be constructed that will allow both individuals and organizations to actively manage their “things” and information in a highly flux environment. The contributions of this paper are twofold: We first discuss the use of security and privacy policies that can offer fine granularity and context‐aware information control in RFID systems. Second, we propose a novel secure and privacy‐preserving tag management protocol that can support such policies. Our protocol has a modular design that allows it to support a set of desirable management operations (viz. tag authentication, delegation, and ownership transfer) while imposing minimal hardware and computational requirements on the tag side. Furthermore, inspired by the European Network and Information Security Agency's Flying 2.0 study, we describe a near‐future air travel scenario to further explain and demonstrate the inner workings of our proposal. Copyright © 2011 John Wiley & Sons, Ltd.
Lidar profilers in the context of wind energy–a verification procedure for traceable measurements
Authors: Gottschall J. , Courtney M. S. , Wagner R. , Jørgensen H. E. , Antoniou I. 
Published: December 2011

ABSTRACTThe need for measuring wind speed and direction at greater heights and at several levels simultaneously gains importance as wind turbines become larger and higher. For this purpose, remote‐sensing profilers become very attractive for resource assessment and power performance testing. However, the existing standards only permit the use of cup anemometers as standard instruments. The main issue preventing the use of remote sensors in such standards is the need to maintain the traceability of the measurements in the international standard system.In this paper, we describe a verification procedure for lidar profilers that enables us to achieve the required traceability. The procedure is based on a direct comparison of the measurements from the lidar and reference sensors mounted on a mast at various height levels. First, the data are corrected and filtered to obtain a representative data set ensuring a repeatable test. Second, a linear regression is applied to the data for each height. The third step is a bin‐average analysis of the lidar error, i.e. the difference between the lidar and reference measurements, forming the basis for the ensuing uncertainty estimation.The results of the verification test are both used to correct the lidar measurements and to derive a corresponding uncertainty budget. A significant limitation of the procedure is the considerable uncertainty introduced by the reference sensors themselves. The decision as to whether to apply the derived correction as a lidar calibration or not therefore mainly depends on the interpretation of this reference uncertainty and the assumed and observed biases. Copyright © 2011 John Wiley & Sons, Ltd.