bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonlinear Parameter Identification for Ordinary Differential Equations
Authors: Wöbbekind Mitja , Kemper Anna , Büskens Christof , Schollmeyer Michael 
Published: November 2013

AbstractIn many applications with dynamical processes parameter depending systems of nonlinear ordinary differential equations (ODE) are formulated. Often the model description does not perfectly match with realistic data. SQP‐methods can be used to identify the parameters of the dynamical model. In conventional approaches the ODE system is solved numerically several times during each of the iteration steps of the optimization process. In this work it is proposed to perform the numerical integration of the ODE system within the optimization process. The benefits of the presented technique will be illustrated by the application of a turbocharger design within the context of diesel engined vehicle development. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solvability and stationarity for the optimal control of variational inequalities with point evaluations in the objective functional
Authors: Hintermüller Michael , Löbhard Caroline 
Published: November 2013

AbstractMotivated by applications in economics and engineering, we consider the optimal control of a variational inequality with point evaluations of the state variable in the objective. This problem class constitutes a specific mathematical program with complementarity constraints (MPCC). In our context, the problem is posed in an adequate function space and the variational inequality involves second order linear elliptic partial differential operators. The necessary functional analytic framework complicates the derivation of stationarity conditions whereas the non‐convex and non‐differentiable nature of the problem challenges the design of an efficient solution algorithm. In this paper, we present a penalization and smoothing technique to derive first order type conditions related to C‐stationarity in the associated Sobolev space setting. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Active damping of rotational load oscillations at container cranes by individual rope length actuation
Authors: Kreuzer Edwin , Radisch Christian 
Published: November 2013

AbstractA particular challenge in the field of container crane control are rotations of the load about its vertical axis when neither special rotational actuators nor variable configurations of the rope directions are available. It is possible to enhance damping of rotational load oscillations by changing the rope lengths individually. Under the assumption of rigid ropes, a model representing the approximate dynamical behavior of the oscillator with three degrees of freedom is developed which reflects the nonlinear coupling effects between the degrees of freedom. This model is used for a stabilizing controller design with only the position of the trolley and the rope lengths actuated. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Balancing Transformations for Infinite‐Dimensional Control Systems
Authors: Reis Timo , Selig Tilman 
Published: November 2013

AbstractIn order to facilitate model reduction by balanced truncation, we introduce state space transformations that can be used to construct an ℓ2‐balanced realization of a regular, linear input‐ouput map with nuclear Hankel‐operator directly from the system generators of an arbitrary, given realization. These balancing transformations are based on factors of the Gramians and, for infinite‐dimensional systems, they are usually unbounded operators. Subsequently the ℓ2‐balanced realization can be truncated in a non‐trivial way to obtain an approximating, finite‐dimensional model. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Model Order Reduction for Unsteady Aerodynamic Applications
Authors: Vendl Alexander , Faßbender Heike 
Published: November 2013

AbstractIn this work a nonlinear model order reduction approach for unsteady aerodynamic applications is presented. It is based on Proper Orthogonal Decomposition (POD). Given a set of snapshots, which are solutions to the full order model, POD yields an optimal basis for representing reduced order solutions of the governing equations. The idea of the reduced order modeling approach in this work is to formulate each time step of the unsteady equations as a steady problem. This yields the so‐called unsteady residual. The unsteady residual is then minimized in the space spanned by the POD basis vectors. As this space is of reduced size, the minimization problem is as well. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Real function reconstruction from sparse Fourier samples
Authors: Wischerhoff Marius 
Published: November 2013

AbstractIn this paper we use the Prony method to reconstruct structured, real‐valued functions from the smallest possible number of equidistantly distributed Fourier samples. In particular, we consider characteristic functions in ${\rm I\!R}^2$ whose supports are unit‐height polygons in the plane with N vertices. We show that these functions can be recovered by 3N Fourier samples. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On unconditionally positivity preserving DG schemes for shallow water flows with shock capturing by adaptive filtering procedures
Authors: Ortleb Sigrun , Meister Andreas 
Published: November 2013

AbstractIn this work, we present an unconditionally positivity preserving implicit time integration scheme for the DG method applied to shallow water flows. For locally refined grids with very small elements, the ODE resulting from space discretization is stiff and requires implicit or partially implicit time stepping. However, for simulations including wetting and drying or regions with small water height, severe time step restrictions have to be imposed due to positivity preservation. Nevertheless, as implicit time stepping demands a significant amount of computational time in order to solve a large system of nonlinear equations for each time step we need large time steps to obtain an efficient scheme. In this context, we propose a novel approach to the strategy of positivity preservation. This new technique is based on the so‐called Patankar trick and guarantees non‐negativity of the water height for any time step size while still preserving conservativity. Due to this modification, the implicit scheme can take full advantage of larger time steps and is therefore able to beat explicit time stepping in terms of CPU time. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Finite Element Method for Spatially Resolved Simulation of Packed Bed Chromatography
Authors: Püttmann Andreas , Nicolai Mike , Behr Marek , von Lieres Eric 
Published: November 2013

AbstractPacked bed chromatography is among the most important unit operations in bio‐chemical process engineering for purifying target molecules from contaminants. A liquid solution of different species is pumped through the chromatography column, which is filled with porous particles (beads). Solute molecules can adsorb to the inner surfaces of these beads with different affinities which leads to different retention times in the column and consequently facilitates the desired separation.We present a stabilized space‐time finite element scheme to solve for fluid flow and mass transfer in miniaturized chromatography columns, which are used in the design and optimization of industrial‐scale applications. Our method can accurately handle realistic size systems with more than 108 degrees of freedom on massively parallel computing facilities. It can also be applied for simulating sections of larger chromatographic beds in lab‐ and process‐scale columns. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenization in fractional elasticity – One spatial dimension
Authors: Waurick Marcus 
Published: November 2013

AbstractIn this note we treat the equations of fractional elasticity in one spatial dimension. After establishing well‐posedness, we use an abstract result in the theory of homogenization to derive effective equations in fractional elasticity with highly oscillating coefficients. The approach also permits the consideration of non‐local operators (in time and space). (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Essential spectrum of Schrödinger operators with δ‐interactions on the union of compact Lipschitz hypersurfaces
Authors: Behrndt Jussi , Exner Pavel , Lotoreichik Vladimir 
Published: November 2013

AbstractIn this note we prove that the essential spectrum of a Schrödinger operator with δ‐potential supported on a finite number of compact Lipschitz hypersurfaces is given by [0, +∞). We emphasize that the union of a family of Lipschitz hypersurfaces is in general not Lipschitz. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bounds on Non‐Real Eigenvalues of Indefinite Sturm‐Liouville Problems
Authors: Behrndt Jussi , Chen Shaozhou , Philipp Friedrich , Qi Jiangang 
Published: November 2013

AbstractIt is known since the early 20th century that regular indefinite Sturm‐Liouville problems may possess non‐real eigenvalues. However, finding bounds for this set in terms of the coefficients of the differential expression has remained an open problem until recently. In this note we prove a variant of a recent result in [1] on the bounds for the non‐real eigenvalues of an indefinite Sturm‐Liouville problem with Dirichlet boundary conditions. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase Field Modeling of Brittle and Ductile Fracture
Authors: Ulmer Heike , Hofacker Martina , Miehe Christian 
Published: November 2013

AbstractThe phase field modeling of brittle fracture was a topic of intense research in the last few years and is now well‐established. We refer to the work [1‐3], where a thermodynamically consistent framework was developed. The main advantage is that the phase‐field‐type diffusive crack approach is a smooth continuum formulation which avoids the modeling of discontinuities and can be implemented in a straightforward manner by multi‐field finite element methods. Therefore complex crack patterns including branching can be resolved easily. In this paper, we extend the recently outlined phase field model of brittle crack propagation [1‐3] towards the analysis of ductile fracture in elastic‐plastic solids. In particular, we propose a formulation that is able to predict the brittle‐to‐ductile failure mode transition under dynamic loading that was first observed in experiments by Kalthoff and Winkler [4]. To this end, we outline a new thermodynamically consistent framework for phase field models of crack propagation in ductile elastic‐plastic solids under dynamic loading, develop an incremental variational principle and consider its robust numerical implementation by a multi‐field finite element method. The performance of the proposed phase field formulation of fracture is demonstrated by means of the numerical simulation of the classical Kalthoff‐Winkler experiment that shows the dynamic failure mode transition. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dislocations in nanowire heterostructures: from discrete to continuum
Authors: Lazzaroni Giuliano , Palombaro Mariapia , Schlömerkemper Anja 
Published: November 2013

AbstractWe discuss an atomistic model for heterogeneous nanowires, allowing for dislocations at the interface. We study the limit as the atomic distance converges to zero, considering simultaneously a dimension reduction and the passage from discrete to continuum. Employing the notion of Gamma‐convergence, we establish the minimal energies associated to defect‐free configurations and configurations with dislocations at the interface, respectively. It turns out that dislocations are favoured if the thickness of the wire is sufficiently large. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Micromechanically‐Based Approaches to Failure in Polymers
Authors: Schänzel Lisa , Dal Hüsnü , Miehe Christian 
Published: November 2013

AbstractRubbery polymers comprise of three‐dimensional network structures, formed by flexible and mobile chains. They exhibit highly non‐linear ground state elastic combined with rate‐dependent inelastic material response. The key challenge in the micromechanically‐based modeling of polymer materials is the construction of micro‐macro transition that provides a bridge between microscopic kinematic variables of a single chain and macroscopic deformation measures of a continuum. The fracture toughness of rubbery polymers shows distinct rate dependency which can be identified through tearing tests. In this contribution, an overview on the micromechanical‐motivated modeling of polymeric materials will be given and different micromechanically‐based approaches to the modeling of rubbery polymers will be discussed. The novel aspect of the contribution is the incorporation of micromechanically‐motivated crack phase field model for the description of rate‐dependent fracture process in rubbery polymers. To do so, the viscoelastic spectrum of rubber network is idealized by a number of Maxwell branches superimposed to a ground‐state elastic spring representing the crosslinked network. The core of the ansatz is the incorporation of rupture of the superimposed network of dangling chains to the fracture process at different loading rates. We demonstrate the modeling capability of the proposed ansatz by means of representative numerical examples. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On local hierarchical refinement and error estimation for isogeometric analysis
Authors: Fußeder Daniela , Vuong Anh‐Vu 
Published: November 2013

AbstractOver the past years a lot of attention was devoted to the investigation of isogeometric analysis, which integrates simulation techniques with computer aided design. In this article we focus on the ingredients for adaptive simulation with isogeometric methods. Local mesh refinement is realized by the usage of hierarchical B‐splines, and different error estimation techniques are discussed. Promising numerical examples are shown in the end. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Next‐generation sequencing to dissect hereditary nephrotic syndrome in mice identifies a hypomorphic mutation in Lamb2 and models Pierson's syndrome
Authors: Bull Katherine R , Mason Thomas , Rimmer Andrew J , Crockford Tanya L , Silver Karlee L , Bouriez‐Jones Tiphaine , Hough Tertius A , Chaudhry Shirine , Roberts Ian SD , Goodnow Christopher C , Cornall Richard J 
Published: November 2013

AbstractThe study of mutations causing the steroid‐resistant nephrotic syndrome in children has greatly advanced our understanding of the kidney filtration barrier. In particular, these genetic variants have illuminated the roles of the podocyte, glomerular basement membrane and endothelial cell in glomerular filtration. However, in a significant number of familial and early onset cases, an underlying mutation cannot be identified, indicating that there are likely to be multiple unknown genes with roles in glomerular permeability. We now show how the combination of N‐ethyl‐N‐nitrosourea mutagenesis and next‐generation sequencing could be used to identify the range of mutations affecting these pathways. Using this approach, we isolated a novel mouse strain with a viable nephrotic phenotype and used whole‐genome sequencing to isolate a causative hypomorphic mutation in Lamb2. This discovery generated a model for one part of the spectrum of human Pierson's syndrome and provides a powerful proof of principle for accelerating gene discovery and improving our understanding of inherited forms of renal disease. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd
Whole‐exome sequencing of pancreatic neoplasms with acinar differentiation
Authors: Jiao Yuchen , Yonescu Raluca , Offerhaus G Johan A , Klimstra David S , Maitra Anirban , Eshleman James R , Herman James G , Poh Weijie , Pelosof Lorraine , Wolfgang Christopher L , Vogelstein Bert , Kinzler Kenneth W , Hruban Ralph H , Papadopoulos Nickolas , Wood Laura D 
Published: November 2013

AbstractPancreatic carcinomas with acinar differentiation, including acinar cell carcinoma, pancreatoblastoma and carcinomas with mixed differentiation, are distinct pancreatic neoplasms with poor prognosis. Although recent whole‐exome sequencing analyses have defined the somatic mutations that characterize the other major neoplasms of the pancreas, the molecular alterations underlying pancreatic carcinomas with acinar differentiation remain largely unknown. In the current study, we sequenced the exomes of 23 surgically resected pancreatic carcinomas with acinar differentiation. These analyses revealed a relatively large number of genetic alterations at both the individual base pair and chromosomal levels. There was an average of 119 somatic mutations/carcinoma. When three outliers were excluded, there was an average of 64 somatic mutations/tumour (range 12–189). The mean fractional allelic loss (FAL) was 0.27 (range 0–0.89) and heterogeneity at the chromosome level was confirmed in selected cases using fluorescence in situ hybridization (FISH). No gene was mutated in >30% of the cancers. Genes altered in other neoplasms of the pancreas were occasionally targeted in carcinomas with acinar differentiation; SMAD4 was mutated in six tumours (26%), TP53 in three (13%), GNAS in two (9%), RNF43 in one (4%) and MEN1 in one (4%). Somatic mutations were identified in genes in which constitutional alterations are associated with familial pancreatic ductal adenocarcinoma, such as ATM, BRCA2 and PALB2 (one tumour each), as well as in genes altered in extra‐pancreatic neoplasms, such as JAK1 in four tumours (17%), BRAF in three (13%), RB1 in three (13%), APC in two (9%), PTEN in two (9%), ARID1A in two (9%), MLL3 in two (9%) and BAP1 in one (4%). Perhaps most importantly, we found that more than one‐third of these carcinomas have potentially targetable genetic alterations, including mutations in BRCA2, PALB2, ATM, BAP1, BRAF and JAK1. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Anthracene‐containing conjugated polymer showing four optical transitions upon doping: A spectroscopic study
Authors: Gasiorowski Jacek , Boudiba Sameh , Hingerl Kurt , Ulbricht Christoph , Fattori Valeria , Tinti Francesca , Camaioni Nadia , Menon Reghu , Schlager Stefanie , Boudida Louiza , Sariciftci Niyazi Serdar , Egbe Daniel Ayuk Mbi 
Published: November 2013

ABSTRACTAn anthracene‐containing poly(arylene‐ethynylene)‐alt‐poly(arylene‐vinylene) (PAE‐PAV) of general constitutional unit (PhCCAnthrCCPhCHCHAnthrCHCH)nbearing two 2‐ethylhexyloxy solubilizing side chains on each phenylene (Ph) unit has been synthesized and characterized. The basic electrochemical characterization was done, showing the existence of two non‐reversible oxidation and one reversible reduction peaks. The optical properties, the real and imaginary part of the dielectric function, were probed using spectroscopic ellipsometry (SE). The vibrational structure of the undoped/doped polymer was investigated using Fourier transformed infrared spectroscopy. A strong change in the polaronic absorption was observed during the doping, which after modeling revealed the existence of two separated transitions. The optical changes upon doping were additionally recorded using the SE technique. Similar to the results from FT‐IR spectroscopy, two new in‐the‐gap absorptions were found. Moreover, the electrical conductivity as well as the mobility of positive carriers were measured. In the undoped state, the conductivity of the polymer was found to be below the detection limit (<μS cm−1), after doping the conductivity increased to 0.69 S cm−1. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2014,52, 338–346
The basis for rootstock resilient to Capnodis species: screening for genes encoding δ‐endotoxins from Bacillus thuringiensis
Authors: Gindin Galina , Mendel Zvi , Levitin Bella , Kumar Pradeep , Levi Tal , Shahi Preeti , Khasdan Vadim , Weinthal Dan , Kuznetsova Tatiana , Einav Monica , Kushmaro Ariel , Protasov Alex , Zaritsky Arieh , Ben‐Dov Eitan 
Published: November 2013

AbstractBACKGROUNDConventional methods often fail to control the flatheaded borers Capnodis spp., major pests of stone fruit trees; the larvae are protected from insecticides and predation because they feed deep in the roots. A potential solution is transgenic trees producing in their roots toxic compounds such as Cry proteins of Bacillus thuringiensis (Bt).RESULTSToxicities against Capnodis larvae were demonstrated by exploiting a recently designed artificial larval diet and an available collection of field isolated Bt. An isolate of Bt tenebrionis (Btt) from commercial bioinsecticide (Novodor) displayed LC50 and LC95 values of 3.2 and 164 mg g−1, respectively, against neonates of Capnodis tenebrionis, whereas values of the most toxic field isolate K‐7 were 1.9 and 25.6 mg g−1 respectively. Weights of surviving larvae after 1 month on diets containing low concentrations of K‐7 (0.1–1.0 mg g−1) were lower than on Btt or untreated larvae. K‐7 was also toxic against larvae of C. cariosa and C. miliaris and found to harbour genes encoding Cry9Ea‐like and Cry23Aa/Cry37Aa binary toxins.CONCLUSIONLarvae of Capnodis spp. are susceptible to Bt Cry toxins. Expressing cry genes active against these pests thus seems a feasible solution towards production of transgenic rootstock trees resilient to the pest. © 2013 Society of Chemical Industry
Magnetic and electromagnetic absorption properties of FeNi alloy nanoparticles supported by reduced graphene oxide
Authors: Sun Chen , Jiang Wei , Wang Yujiao , Sun Danping , Liu Jie , Li Pingyun , Li Fengsheng 
Published: November 2013

AbstractFeNi alloy nanoparticles (NPs) supported by reduced graphene oxide (RGO) (FeNi/RGO nanocomposites) were successfully synthesized through in‐situ reduction. Large amounts of sphere‐like FeNi NPs are uniformly deposited on the RGO nanosheets. The magnetic hysteresis measurement reveals the ferromagnetic behavior of the nanocomposites at room temperature. According to the electromagnetic (EM) characteristics, the FeNi/RGO nanocomposites show outstanding EM absorption properties in the 2–18 GHz range, as evidenced by the wide effective absorption bandwidth (up to 3.3 GHz, with reflection loss RL < –10 dB) and a minimal RL (–32 dB) at 12.4 GHz with a thickness of 1.5 mm. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Space–time clustering and the permutation moments of quadratic forms
Authors: Zhou Yi‐Hui , Mayhew Gregory , Sun Zhibin , Xu Xiaolin , Zou Fei , Wright Fred A. 
Published: November 2013

AbstractThe Mantel and Knox space–time clustering statistics are popular tools to establish transmissibility of a disease and detect outbreaks. The most commonly used null distributional approximations may provide poor fits, and researchers often resort to direct sampling from the permutation distribution. However, the exact first four moments for these statistics are available, and Pearson distributional approximations are often effective. Thus, our first goals are to clarify the literature and make these tools more widely available. In addition, by rewriting terms in the statistics, we obtain the exact first four permutation moments for the most commonly used quadratic form statistics, which need not be positive definite. The extension of this work to quadratic forms greatly expands the utility of density approximations for these problems, including for high‐dimensional applications, where the statistics must be extreme in order to exceed stringent testing thresholds. We demonstrate the methods using examples from the investigation of disease transmission in cattle, the association of a gene expression pathway with breast cancer survival, regional genetic association with cystic fibrosis lung disease and hypothesis testing for smoothed local linear regression. © The Authors.Statpublished by John Wiley & Sons Ltd.