bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of finite‐dimensional mechanical systems on Galilean manifolds
Authors: Capobianco Giuseppe , Winandy Tom , Eugster Simon R. 
Published: November 2019

AbstractAs presented in the related PAMM contribution ‘Kinematics of finite‐dimensional mechanical systems on Galilean manifolds’, the state space of a time‐dependent finite‐dimensional mechanical system is defined as an affine subbundle of the tangent bundle to the Galilean manifold modeling the generalized space‐time of the system. The second‐order vector field on the state space that describes the system's motion can be associated with a differential two‐form called the action form of the mechanical system. In this paper, we postulate the action form for time‐dependent finite‐dimensional mechanical systems. Moreover, we show that Lagrange's equations of the second kind can be derived as a chart representation of the conditions that define the second‐order vector field which describes the motion.
Verification and Validation of a 2D energy based peridynamic state‐based failure criterion
Authors: Willberg Christian , Rädel Martin , Heinecke Falk 
Published: November 2019

AbstractThe paper presents a validation approach for an enhanced energy‐based failure model for state‐based peridynamics. Model robustness and validity of predicted crack initiation and propagation is demonstrated for a double cantilever beam. Tensile tests using the same material and energy release rate from the prior simulations are used to predict specimen failure. The model is implemented in the software Peridigm and will be published open‐source.
Frequency‐bounded Delay and Sum: A modified Damage Detection Method in thin‐walled Plates
Authors: Sattarifar Afshin , Nestorović Tamara 
Published: November 2019

AbstractThe delay‐and‐sum (DaS) methodology is implemented in the current study to depict the probability of damage presence on an aluminum plate. Compared to previous researches, the introduced modification in this work attempts to decrease the dependency of the method on the chosen frequency. Firstly, the propagation of the Lamb waves in the plate is modeled numerically employing commercial finite element package, ABAQUS. Additionally, an experimental setup is built, in which piezo patches are utilized to excite the Lamb wave and to measure the corresponding response on the plate as well. Analysis of the experimental results shows the feasibility of the method for damage detection.
Dynamic feedback control through wall suction in shear flows
Authors: Linkmann Moritz , Eckhardt Bruno 
Published: November 2019

AbstractFlow control is of interest in many open and wall‐bounded shear flows in order to reduce drag or to avoid sudden large fluctuations that may lead to material failure. An established means of control is the application of suction through a porous wall. Here, we combine suction with a feedback strategy whereby the suction velocity is adjusted in response to either the kinetic energy or the shear stress at the bottom wall. The control procedure is then used in an attempt to stabilize invariant solutions and to carry out direct numerical simulations with a prescribed value of the friction coefficient.
An SDE waveform‐relaxation method with application in distributed neural network simulations
Authors: Bolten Matthias , Hahne Jan 
Published: November 2019

AbstractWaveform‐relaxation methods are a set of iterative methods to solve systems of differential equations by dividing them into subsystems. Several of these methods, such as the Jacobi waveform‐relaxation method, enable potential for parallelization across the system and are for that reason interesting in applications with a highly parallel setting. Here we present an SDE waveform‐relaxation methods with applications in the fields of computational neuroscience. We give a short overview how and where the application of the method can speed up the simulation of functionally inspired rate‐based units in a distributed neural network simulator that was originally designed for biologically grounded spiking neuron models.
A Frequency‐Uniform and Pitch‐Invariant Time‐Frequency Representation
Authors: Schulze Sören , King Emily J. 
Published: November 2019

AbstractWe introduce the terms frequency‐uniformity and pitch‐invariance in order to characterize time‐frequency representations. A frequency‐uniform representation has the property that it displays Dirac transients as a straight line in the spectrogram, while a pitch‐invariant representation translates pitch change into shifts, which is adequate for melodic instruments. We propose a novel representation that fulfills both criteria.
Energy absorption of re‐entrant auxetic structures: a parametric study
Authors: Mekala Narasimha Rao , Bühring Jannik , Aghdam Nima Jafarzadeh , Schröder Kai-Uwe 
Published: November 2019

AbstractThe present research is focusing on the better understanding of the behaviour of the re‐entrant auxetic structures subjected to impact loads. Various results like the energy absorption capacity, impact force and force‐displacement curves are predicted by performing numerical simulations in ABAQUS. Furthermore, some comparative studies have been performed on different parameters associated with the geometry and the impactor mass to gain a better understanding of re‐entrant auxetic structures on its performance under the impact, mainly focusing on energy absorption characteristics.
Comparison of MRI measurements and CFD simulations of hemodynamics in intracranial aneurysms using a 3D printed model ‐ Influence of noisy MRI measurements
Authors: Giese Daniel , Heinlein Alexander , Klawonn Axel , Knepper Jascha , Sonnabend Kristina 
Published: November 2019

AbstractMRI (Magnetic Resonance Imaging) measurements and CFD (Computational Fluid Dynamics) simulations for blood flow in intracranial aneurysms are compared for a benchmark problem. In particular, it is shown that noise and other artifacts in the MRI measurements have an influence on certain properties of the flow field, e.g., on the boundary flow and mass conservation.
Accuracy considerations of mixed explicit implicit schemes for embedded boundary meshes
Authors: May Sandra , Berger Marsha , Laakmann Fabian 
Published: November 2019

AbstractWe consider a mixed explicit implicit finite volume scheme for solving the advection equation on a Cartesian cut cell mesh: the scheme couples an implicit time stepping scheme on cut cells with an explicit time stepping scheme on cells away from the cut cells by means of flux bounding. We examine the accuracy of the resulting mixed scheme to see if a second‐order explicit and a second‐order implicit scheme result in a second‐order mixed scheme.
On mechanical DAE systems within the framework of optimal control
Authors: Schneider Simeon , Betsch Peter 
Published: November 2019

AbstractThere are different approaches how to treat constrained mechanical systems within the framework of optimal control. One of them is to treat the constraints as constant states in time. An other approach is to ensure the equivalence of either solving an ordinary differential equation system or a differential algebraic equation system as constraints of the optimal control problem. The embedding of both approaches will be shown and numerical examples will show the influence of the embedding on the underlying necessary optimality conditions of the optimal control problem.
IMEX‐ODTLES: A multi‐scale and stochastic approach for highly turbulent flows
Authors: Medina Méndez Juan A. , Glawe Christoph , Starick Tommy , Schöps Mark S. , Schmidt Heiko 
Published: November 2019

AbstractThe stochastic One‐Dimensional Turbulence (ODT) model is used in combination with a Large Eddy Simulation (LES) approach in order to illustrate the potential of the fully coupled model (ODTLES) for highly turbulent flows. In this work, we use a new C++ implementation of the ODTLES code in order to analyze the computational performance in a classical incompressible turbulent channel flow problem. The parallelization potential of the model, as well as its physical and numerical consistency are evaluated and compared to Direct Numerical Simulations (DNSs). The numerical results show that the model is capable of reproducing a representative part of the DNS data at a cheaper computational cost. This advantage can be enhanced in the future by the implementation of a straightforward parallelization approach.
Adjoint based topology optimization of a duct bend
Authors: Goeke Stephan , Wünsch Olaf 
Published: November 2019

AbstractThe cooling performance of a duct is a complex interaction between its shape, position inside the surrounding material and the resulting flow. Hence a change in the geometry does effect both the pressure loss as well as the temperature distribution. Due to this coupling of heat transfer and fluid flow a numerical solution is often computationally expensive. Lowering the number of these evaluation steps is therefore crucial. A gradient based optimization method promises high optimization speed if the gradient can be computed effortlessly. The adjoint method in particular offers a low computational cost to calculate this gradient and is hence chosen for the optimization. In this contribution the continuous adjoint equations including conjugate heat transfer are used to optimize a duct bend. A level‐set is used to differentiate the fluid and solid regions. The aim of the optimization is to lower the temperature of a wall inside the heated solid domain. The Reynolds number of the initial design is varied and the effects on the optimization are studied.
Magneto‐electric product properties of multiferroic composites
Authors: Labusch Matthias , Schröder Jörg 
Published: November 2019

AbstractMagneto‐electric (ME) composite materials enable a coupling between magnetization and electric polarization. This magneto‐electric coupling finds application in sensor technology and data storage devices. Since this coupling is a strain‐induced product property which arises due to the interaction of the different phases, suitable material models for the individual phases as well as microscopic defects, such as pores, have to be considered for precise numerical simulations. In this contribution we implemented suitable material models for both phases describing the behavior on the microscopic level and considered pores which influence the overall ME response. In order to determine the effective properties a two‐scale finite element (FE2) homogenization approach is performed. The remanent magnetization behavior is described using a Preisach operator whereas the remanent electric polarization arises due to a ferroelectric/‐elastic switching criterion based on a change in the free energy.
System‐theoretic model order reduction with pyMOR
Authors: Balicki Linus , Mlinarić Petar , Rave Stephan , Saak Jens 
Published: November 2019

AbstractThis paper shows recent developments in pyMOR, in particular the addition of system‐theoretic methods. All methods are implemented using pyMOR's abstract interfaces, which allows the application to partial differential equation (PDE) models implemented with third‐party libraries. We demonstrate this by applying balanced truncation to a PDE model discretized in FEniCS.
Martensitic transformation at a crack under mode I and II loading
Authors: Schmidt Simon , Dornisch Wolfgang , Müller Ralf 
Published: November 2019

AbstractMetastable austenitic steels can undergo phase transformation. As an allotrope two crystal configurations are of interest: the softer austenitic parent phase and the martensitic phases. Here, the bain orientation relationship leads to distinct orientations for the martensitic variants with a different transformation strain [7]. A phase field approach is used to model the transformation, where a multi‐valued order parameter

identifies the austenitic parent phase and the martensitic variants. This allows to define bulk and surface energies as regularized functions in terms of the order parameter and its gradient. The kinetics of the martensitic transformation are temperature dependent. Temperatures below an equilibrium temperature favour the growth of the martensitic phase, whereas temperatures above the equilibrium favour the austenitic phase. Approaching the equilibrium temperature slows down the transformation [5]. In this work we consider a static crack under mode I and mode II loading.
Multifidelity Reliability Estimation
Authors: Proppe Carsten 
Published: November 2019

AbstractMulti‐fidelity estimation combines the output of simulation models of different approximation quality and from different sources in order to obtain efficient estimators for a quantity of interest. It relies on a model hierarchy that is established either by means of an approximation parameter or the Pearson correlation of the model outputs. Here, alternative measures based on the copula or on information theory are introduced in order to order models. To combine the results from the model hierarchy, information fusion methods based on differences of the quantity of interest and on conditional probabilities are introduced. They are combined with the moving particles method in order to yield efficient estimators for the probability of failure.
Gaussian process based surrogate modelling of acoustic systems
Authors: Kohlsche Thomas , Lippert Stephan , von Estorff Otto 
Published: November 2019

AbstractThe numerical simulation of acoustic problems is, for itself, a quite difficult task since the underlying systems are usually highly complex with a broad frequency range and high sensitivity. Due to this complexity and the corresponding computational burden, tasks like optimization and uncertainty quantification (UQ) are seldom performed in acoustics. Especially when dealing with polymorphic uncertainties where combined techniques of UQ might be required, a direct use of the model is not viable. To allow such engineering tasks, the construction of a cheap surrogate or reduced model is common practice in order to allow a large number of model evaluations at low costs.For acoustic systems, the construction of a reasonably accurate surrogate model can become a challenging task since many systems operate in the frequency domain where phenomena like resonance and interference can cause highly nonlinear responses. In this paper, a surrogate model based on the combination of a parametric model for capturing local nonlinearities and a random process regression for modelling the global trend is presented. The basic procedure based on previous works of the authors is extended to a predict the system response both for unobserved parameters and frequencies. The procedure is demonstrated for a representative example namely the acoustic simulation of a car interior, and further improvements in accuracy and efficiency by the usage of multilevel information are discussed.
An Overview of Simulated Hydrogel Behaviour under Various Kinds of Stimulation
Authors: Keller Karsten , Wallmersperger Thomas , Ricken Tim 
Published: November 2019

AbstractPolyelectrolytic gels placed in aqueous solution show effects under various kinds of stimulation. The stimuli could be e.g. of chemical, electrical, mechanical or thermal nature. The hydrogels react via uptake or delivery of mobile ions and solvent, and they show enormous swelling capabilities. This multifunctional behaviour is potentially attractive for chemo‐electro‐mechanical energy converters or for the use as actuators or sensors. In the present research, anionic and cationic hydrogels are investigated, which means that the polymer network contains anionic or cationic bound charged groups. The chemical stimulation is applied by a change of boundary conditions in the solution bath for the salt concentrations. The electrical stimulus is realized by incorporating electrodes between which an electric potential difference is applied. The mechanical stimulus is realized by prescribed displacements at a boundary of the hydrogel itself. The thermal stimulus is applied as transient temperature change over the whole domain, incorporating temperature‐dependent material parameters and osmotic pressure differences. The reactions of the hydrogel differ depending on the sensitivity of the gel to the applied stimulus. The incorporated chemo‐electro‐mechanical model enhanced with thermal dependencies is capable of giving local concentrations, electric potential and mechanical displacements.
Towards a New Peer Review Concept for Scientific Computing ensuring Technical Quality, Software Sustainability, and Result Reproducibility
Authors: Anzt Hartwig , Cojean Terry , Kühn Eileen 
Published: November 2019

AbstractIn this position paper we argue for implementing an alternative peer review process for scientific computing contributions that promotes high quality scientific software developments as fully‐recognized conference submission. The idea is based on leveraging the code reviewers' feedback on scientific software contributions to community software developments as a third‐party review involvement. Providing open access to this technical review would complement the scientific review of the contribution, efficiently reduce the workload of the undisclosed reviewers, improve the algorithm implementation quality and software sustainability, and ensure full reproducibility of the reported results. Using this process creates incentives to publish scientific algorithms in open source software – instead of designing prototype algorithms with the unique purpose of publishing a paper. In addition, the comments and suggestions of the community being archived in the versioning control systems ensure that also community reviewers are receiving credit for the review contributions – unlike reviewers in the traditional peer review process. Finally, it reflects the particularity of the scientific computing community using conferences rather than journals as the main publication venue.
Risk factors and management of corticosteroid‐induced hyperglycaemia in paediatric acute lymphoblastic leukaemia
Authors: Gregoriou Kyriacos , Craigie Ian , Gibson Brenda , Mason Avril , Shaikh Mohamad Guftar 
Published: November 2019

AbstractCorticosteroids are incorporated into protocols for the treatment of acute lymphoblastic leukaemia, and hyperglycaemia is a recognised side effect. Corticosteroids exert their hyperglycaemic effect with a multifactorial mechanism. Complications of hyperglycaemia include an increased risk of infection – bacterial, viral and fungal. Approximately half of the children who develop corticosteroid‐associated hyperglycaemia are predicted to require insulin treatment, with age and obesity having found to be predictive factors. Fasting and random glucose values can be used to define hyperglycaemia. This review focuses on the published evidence for significant predictive factors for the development of corticosteroid‐induced hyperglycaemia and provides guidance on management.
Preparation of hexakis (4‐aldehyde phenoxy) cyclotriphosphazene grafted kaolinite and its synergistic fire resistance in poly (butylene succinate)
Authors: Zhang Sheng , Li Yuchun , Guo Jia , Gu Lingling , Li Hongfei , Fei Bin , Sun Jun , Gu Xiaoyu 
Published: November 2019

AbstractHexakis (4‐aldehyde phenoxy) cyclotriphosphazene (HAPCP) was synthesized firstly and then it was grafted onto the exfoliated kaolinite (Kaol) to prepare K‐HAPCP. The structure of HAPCP and K‐HAPCP was well characterized. K‐HAPCP was used as synergistic agent in poly (butylene succinate) (PBS)/intumescent flame retardants (IFR) composites. The combustion behavior of PBS composites was reflected by limited oxygen index (LOI), vertical burning (UL‐94), and cone calorimeter test. The thermal stability was traced by thermogravimetric analysis. PBS is highly flammable with the LOI value of only 21.9% and cannot pass any UL‐94 grade during vertical burning test. By the presence of 22 wt% IFR and 3 wt% K‐HAPCP, the LOI of PBS composite is sharply increased to 40.3% and the sample can pass UL‐94 V‐0 rating with excellent anti‐dripping properties. Moreover, the degradation behavior is investigated and the probable flame retardant mechanism is also proposed.
Theoretical investigation of a cation‐controllable molecular shuttle of tetracationic cyclophane
Authors: Liang Zhongshuai , Zheng Xin , Wang Hailong , Wang Xueye 
Published: November 2019

AbstractAn ion‐controllable molecular switch comprising a tetracationic cyclophane (CBPQT4+) macroring bound to [2]pseudorotaxanes has been investigated by density functional theory. The role of noncovalent interactions has been assessed with the reduced density gradient method and binding energies. Moreover, the natural bond orbital is used to evaluate the strength of hydrogen bonding, π–π and cation–π interactions. The electrostatic repulsions between the bound K+ ion and tetracationic cyclophane were also calculated. The theoretical calculations confirmed that the 18‐crown‐6 derivative containing a 1,5‐dioxynaphthalene residue station exhibits the strongest binding interaction, and the hydrogen bond and electrostatic forces are prevalent at all stations. These calculated results are in agreement with the hypothesis proposed by Stoddart.
Synthesis and characterization of 9,9‐bis(4‐hydroxyphenyl and 4‐aminophenyl)dibenzofluorenes: Novel fluorene‐based monomers
Authors: Seesukphronrarak Surasak , Kawasaki Shinichi , Kuwata Shigeki , Takata Toshikazu 
Published: November 2019

ABSTRACTTwo novel 9,9‐difunctionalized fluorene‐type monomers, 9,9‐bis(4‐hydroxyphenyl‐ and 4‐aminophenyl)‐2,3:6,7‐dibenzofluorenes, are synthesized by the reaction of dibenzenzofluorenone with phenol and aniline. These monomers are used for the preparation of polyester and polyimide as the typical polymers to evaluate the property change such as thermal stability caused by the benzene rings fused to the fluorene skeleton with keeping good solubility, in comparison with the polymers derived from simple fluorenone. In fact, these two new polymers have the fairly enhanced thermal stability and refractive index value along with satisfactory solubility in organic solvents, enough to emphasize the fusion effect. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2602–2605
Bronchoscopy in severe childhood asthma: Irresponsible or irreplaceable?
Authors: Januska Megan N. , Goldman David L. , Webley Wilmore , Teague W. Gerald , Cohen Robyn T. , Bunyavanich Supinda , Vicencio Alfin G. 
Published: November 2019

AbstractFor children with severe asthma, guideline‐based management focuses on the escalation of anti‐inflammatory and bronchodilatory medications while addressing comorbid conditions. Bronchoscopy, in this context, has been relegated to ruling out asthma mimickers. More recently, however, there have been questions surrounding the clinical utility of bronchoscopy in severe childhood asthma. In this solicited lecture summary, we discuss the past, present, and potential future applications of bronchoscopy in severe childhood asthma.
Enhanced Controllability of Fries Rearrangements Using High‐Resolution 3D‐Printed Metal Microreactor with Circular Channel
Authors: Lee Hyune‐Jea , Roberts Robert C. , Im Do Jin , Yim Se‐Jun , Kim Heejin , Kim Ji Tae , Kim Dong‐Pyo 
Published: November 2019

AbstractHigh‐resolution 3D‐printed stainless steel metal microreactors (3D‐PMRs) with different cross‐sectional geometry are fabricated to control ultrafast intramolecular rearrangement reactions in a comparative manner. The 3D‐PMR with circular channel demonstrates the improved controllability in rapid Fries‐type rearrangement reactions, because of the superior mixing efficiency to rectangular cross‐section channels (250 µm × 125 µm) which is confirmed based on the computational flow dynamics simulation. Even in case of very rapid intramolecular rearrangement of sterically small acetyl group occurring in 333 µs of reaction time, the desired intermolecular reaction can outpace to the undesired intramolecular rearrangement using 3D‐PMR to result in high conversion and yield.