bluuebunny/crossref_metadata_2025_split huggingface dataset:
Review of the 6th International Consultation on Incontinence: Primary prevention of urinary incontinence
Authors: Palmer Mary H. , Cockerell Rowan , Griebling Tomas L. , Rantell Angie , van Houten Paul , Newman Diane K. 
Published: November 2019

AbstractAimsTo report the state of the science on primary prevention of urinary incontinence (UI) in adults from the 6th International Consultation on Incontinence with an update through January 2019.MethodsOnline databases PubMed, CINAHL, PsycInfo, and Medline were searched in March 2016 and February 2019 with a focus on literature published after 2010. The International Consultation on Urological Diseases modified Oxford Centre for Evidence‐Based Medicine Levels of Evidence and grades of recommendation were used to evaluate the literature.ResultsGrade B recommendations to prevent UI in pregnant and postpartum women are available and promising evidence exists for educational interventions to prevent UI up to 2 years in older women. There is little evidence for adding preoperative pelvic floor muscle exercises to postprostatectomy pelvic floor muscle exercises for men to regain continence. Insufficient evidence exists for the effectiveness of screening for UI in women. The absence of information on primary prevention remains for adolescents, nulliparous and perimenopausal women, and middle‐aged and aged men and women.ConclusionsFew primary prevention interventions for UI exist for specific populations, especially pregnant and postpartum women. Research interest in developing foundational knowledge to design these interventions is growing.
New targets for overactive bladder—ICI‐RS 2109
Authors: Fry Christopher Henry , Chakrabarty Basu , Hashitani Hikaru , Andersson Karl‐Erik , McCloskey Karen , Jabr Rita I. , Drake Marcus J. 
Published: November 2019

AbstractAimTo review evidence for novel drug targets that can manage overactive bladder (OAB) symptoms.MethodsA think tank considered evidence from the literature and their own research experience to propose new drug targets in the urinary bladder to characterize their use to treat OAB.ResultsFive classes of agents or cellular pathways were considered. (a) Cyclic nucleotide–dependent (cyclic adenosine monophosphate and cyclic guanosine monophosphate) pathways that modulate adenosine triphosphate release from motor nerves and urothelium. (b) Novel targets for β3 agonists, including the bladder wall vasculature and muscularis mucosa. (c) Several TRP channels (TRPV1, TRPV4, TRPA1, and TRPM4) and their modulators in affecting detrusor overactivity. (d) Small conductance Ca2+‐activated K+ channels and their influence on spontaneous contractions. (e) Antifibrosis agents that act to modulate directly or indirectly the TGF‐β pathway—the canonical fibrosis pathway.ConclusionsThe specificity of action remains a consideration if particular classes of agents can be considered for future development as receptors or pathways that mediate actions of the above mentioned potential agents are distributed among most organ systems. The tasks are to determine more detail of the pathological changes that occur in the OAB and how the specificity of potential drugs may be directed to bladder pathological changes. An important conclusion was that the storage, not the voiding, phase in the micturition cycle should be investigated and potential targets lie in the whole range of tissue in the bladder wall and not just detrusor.
Numerical method to determine the inverse solution of two impacting rods of non‐constant cross section
Authors: Burgert Jens , Seemann Wolfgang 
Published: November 2019

AbstractImpacting rods are used in several scientific experiments and in everyday tools such as drilling machines. For deep hole drillings, the efficiency of the drilling process can be improved by shaping the longitudinal wave that is transmitted through the drill rod to the drill bit [1]. The approach implemented in this contribution adjusts the longitudinal wave shape by varying the geometry of the impacting piston.
Reduction of stiffness‐induced round‐off errors in chemical reaction systems
Authors: Lukassen Axel Ariaan , Kiehl Martin 
Published: November 2019

AbstractThe timescales of chemical reactions range from nanoseconds to minutes. Hence, chemical reaction systems result in stiff systems of differential equations. Usually, implicit integration schemes are used in order to solve these stiff systems of differential equations. Thus, Newton's method is used in order to solve a nonlinear equation system in each time step. Thereby the evaluation of the chemical source term requests subtraction of very large numbers, and round‐off errors by cancellation occur. This can cause severe convergence problems within Newton's method, resulting in step size reductions. The system of differential equations is replaced by a less stiff modified system in order to reduce the round‐off errors and the computing time. Thereby the approximation error between the given system of differential equations and the modified system of differential equations is smaller than the given tolerance.
Mixed frameworks and structure preserving integration for coupled electro‐elastodynamics
Authors: Franke Marlon , Ortigosa Rogelio , Janz Alexander , Gil Antonio J. , Betsch Peter 
Published: November 2019

AbstractIn the present contribution new approaches for the design of structure preserving time integrators for nonlinear coupled problems are proposed. Polyconvexity inspired energy functionals are obtained by using the rediscovered tensor cross product which greatly simplifies the algebra, see [1]. In this connection an extended kinematic set, consisting of the right Cauchy‐Green tensor, its co‐factor and its Jacobian, is introduced. On this basis coupled problems like e.g. non‐linear thermo‐elastodynamics, see [2] or electro‐elastodynamics, see [3], can be considered. Furthermore the formulations are readily extendible for mixed Hu‐Washizu type formulations where the extended kinematic set is introduced as unknown field. In particular in [1] an elegant cascade system of kinematic constraints was introduced for elastodynamics, crucial for the satisfaction of the required conservation properties of a new family of energy momentum (EM) consistent time integrators. The objective of the present contribution is the introduction of new mixed variational principles for EM consistent time integrators in electro‐elastodynamics, hence bridging the gap between the previous works [3] and [1], opening the possibility to a variety of new finite element implementations, see [4]. The following characteristics of the proposed EM consistent time integrator make it very appealing: (i) the new family of time integrators can be shown to be thermodynamically consistent and second order accurate; (ii) piecewise discontinuous interpolation of the mixed fields is carried out in order to obtain a computational cost comparable to that of standard displacement, electric potential formulations. Eventually, the superior numerical performance of the proposed formulation is demonstrated.
Investigation of the Mechanical Behavior of Polystyrene using Molecular Dynamics
Authors: Ries Maximilian , Steinmann Paul , Pfaller Sebastian 
Published: November 2019

AbstractPolymer nanocomposites exhibit highly promising material properties caused by their molecular structure. Multiscale techniques are used to gain a deeper understanding of the influence of molecular mechanisms on the macro scale. Especially domain composition coupling approaches, e.g. the Capriccio method [1], require a precise match of the constitutive models of the coupled domains. To this end, in this contribution a methodology to characterize the material behavior of polymers using the widely used Molecular Dynamics approach is presented. Exemplary, polystyrene is investigated as a model system and the results of time proportional and time periodic uniaxial deformation tests as well as relaxation and creep tests are briefly discussed.
Dynamical Characteristics of Electromechanical Energy Dissipation due to Translatory Motion: A Minimal Example
Authors: Boy Felix , Hetzler Hartmut , Tchomgue Simeu Arnold 
Published: November 2019

AbstractElectromechanical systems cover a broad technological range of application. Typical examples are electrical machines, eddy current brakes, or different types of actors and sensors. Their dynamical behaviour is affected by some challenging peculiarities: among those are strong geometrical and physical non‐linearities. Consequently, all these effects may result in different kinds of vibration issues. Within this contribution, the classical textbook example of a simple mechanical oscillator is coupled with a magnetic and an electrical circuit. The dynamical characteristics of this system are discussed with respect to equilibria and stationary solutions. Non‐linear periodic solutions are approximated using the harmonic‐balance method.
Analysis of Cahn‐Hilliard‐Brinkman models for tumour growth
Authors: Ebenbeck Matthias , Garcke Harald 
Published: November 2019

AbstractWe introduce and mathematically analyse a new Cahn–Hilliard–Brinkman model for tumour growth allowing for chemotaxis. Outflow boundary conditions are considered in order not to influence tumour growth by artificial boundary conditions. Existence of global‐in‐time weak solutions is shown in a very general setting.
An error bound for the standard deviation in model order reduction of linear stochastic Galerkin systems
Authors: Pulch Roland , Narayan Akil 
Published: November 2019

AbstractWe apply the stochastic Galerkin method to a linear dynamical system including random parameters. The balanced truncation technique yields a model order reduction of the stochastic Galerkin system. We prove an error bound for a quadratic‐type output: the standard deviation of a quantity of interest. Numerical results are demonstrated for a test example.
Simulation of Thermoelastic Problems with the Finite Element Method
Authors: Matter Fabian , Ziegler Pascal , Iroz Igor , Eberhard Peter 
Published: November 2019

AbstractDisc brakes convert kinetic energy into thermal energy in order to slow down vehicles. During the braking process enormous heat flows and temperature gradients occur in the system. Because heating leads to a change in shape for most materials, it is important to take the temperature and its influence into account during the design process. The interaction between the structure and the heat in disc brakes can be described with methods from thermoelasticity. To simulate thermoelastic behaviour the Finite Element Method is commonly used. The thermal and mechanical domain are taken into account by coupling the equation of motion and the heat equation. However, in transient analysis often the problem occurs of different time scales of the structural and thermal dynamics for many technically relevant materials, like steel. For metallic materials the time constant of structural dynamics is much smaller than those of thermal dynamics. This complicates an efficient transient simulation. In the present work the implementation of a Finite Element Method in thermoelasticity and associated investigations are shown. The method is applied to various parts and load cases. Also different approaches to deal with the different time scales will be shown. Heuristic methods like mass‐scaling as well as more mathematically oriented approaches like model order reduction are presented.
Reduction of a district heating model using network decomposition
Authors: Rein Markus , Mohring Jan , Damm Tobias , Klar Axel 
Published: November 2019

AbstractIn this contribution we study model order reduction of nonlinear transport networks for district heating systems. In these, heating energy injected at a centralized power plant is transported to consumers. They are modeled by a hyperbolic differential algebraic system with large state space dimension. The network structure introduces sparse system dynamics, which transform to a dense reduced system leading to unacceptable computational costs [1]. To exploit the benefits of sparsity, sub‐parts of the network are reduced separately in a structure preserving way using Galerkin projection [2]. After introducing the dynamical model, we discuss a decomposition strategy which aims at minimizing the number of observables for each subnetwork. We demonstrate its numerical benefits at an existing large scale heating network.
Spectral Super Elements for Beams with Arbitrary Cross Section
Authors: Greim Axel , Müller Gerhard 
Published: November 2019

AbstractSpectral Super Elements are semi‐analytical elements for the calculation of the wave propagation in structures with a constant cross section. They base on a finite element discretization in the cross‐sectional directions and wave functions as ansatz for the longitudinal direction. No discretization in the latter direction has to be carried out and therefore the number of degrees of freedom is independent of the length the structure.The wave functions used as ansatz are gained as eigenvalues (wave numbers) and –vectors (wave forms) from a quadratic eigenvalue problem of the infinite structure (in longitudinal direction). The infinite structure is reduced to a 2D problem with the help of a Fourier transformation in longitudinal direction. This method is called Waveguide Finite Element Method or 2,5D Finite Element Method in literature.In this study we compare the performance of Spectral Super Elements for beams with arbitrary cross sections with analytical solutions for the Euler‐Bernoulli beam at low frequencies and with results form a 3D Finite Element analysis with commercial software for higher frequencies.
Viscous dissipation in DG methods for turbulent incompressible flows
Authors: Lehrenfeld Christoph , Lube Gert , Schroeder Philipp W. 
Published: November 2019

AbstractNowadays, (high‐order) DG methods, or hybridised variants thereof, are widely used in the simulation of turbulent incompressible flow problems. For turbulence simulations, and especially in the practically relevant situation of strong under‐resolution, it is important to distinguish between the resolved physical dissipation rate and the contribution of numerical dissipation originating from the underlying method. In this note, a certain ambiguity related to such a decomposition for the viscous effects in a DG‐discretised fluid flow problem, which is due to the discontinuity of the approximate solution, is addressed. A novel but rather natural decomposition into ‘physical’ and ‘numerical’ viscous dissipation is proposed for a class of DG methods. Based on a typical 3D benchmark problem for decaying turbulence, its meaningfulness is confirmed numerically. In order to justify the term ‘dissipation’, both the physical and the numerical contributions for the proposed additive decomposition are provably non‐negative (possibly zero).
Steady transonic dense gas flow past two‐dimensional compression/expansion ramps revisited
Authors: Kluwick A. , Cox E. A. 
Published: November 2019

AbstractSupersonic flow past compression/expansion ramps represents a canonical problem in fluid dynamics which has been studied extensively in the past assuming perfect gas behaviour. More recently real gas effects on such flows have received increasing attention as part of efforts, among others, to increase the efficiency of Organic Rankine Cycles for decentralized power plants. Of special interest in this connection are dense gases of Bethe–Zel'dovich–Thompson fluids which have the distinguishing property that the so called fundamental derivative of gasdynamics Γ takes on negative values in the general neighbourhood of the thermodynamic critical point. Asymptotic analysis of the transonic flow regime has so far concentrated on cases where the unperturbed state with pressure p0, density ρ0 and entropy s0 is close to the transition curve Γ = 0 in the pressure specific volume plane such that |Γ0| ≪ 1,

, Kluwick and Cox [1], [2]. These studies have revealed a number of new phenomena and a non‐uniqueness of solutions exceeding that known from the theory of perfect gases.Here we extend the analysis to cover flows where the unperturbed state in the p, 1/ρ plane is in the vicinity of the point on the transition line where Γ and Λ vanish simultaneously. Such flows have |Γ0| ≪ 1, |Λ0| ≪ 1,

and are of considerable practical interest as isentropes that can be realized experimentally at present just barely enter the negative Γ region. Again an increased wealth of possible solutions is observed.
Sensitivity in Machining Systems
Authors: Hamann Dominik , Eberhard Peter 
Published: November 2019

AbstractThe simulation‐based assessment of the stability of machining processes can be an important step in the design of these processes. In order to achieve best possible processes, considering the quality of the surface of workpieces and cycle times, gradients are almost mandatory. Our contribution is a work flow for including varying workpiece dynamics in sensitivity analysis of a predefined machining process.
Shape optimization: what to do first, optimize or discretize?
Authors: Bergmann Ronny , Herzog Roland , Loayza-Romero Estefanía , Welker Kathrin 
Published: November 2019

AbstractIn general, it is not easy to decide whether to use a discretize–then–optimize or optimize–then–discretize approach to solve PDE‐constrained optimization problems. Shape optimization problems are particularly challenging due to the infinite dimensional, nonlinear structure of shape spaces. One option to overcome this drawback is to choose finite dimensional shape spaces, i.e., to discretize first. Nevertheless, this limits the amount of available tools coming from function spaces. In this note, we aim to show advantages and disadvantages of both approaches based on a simple shape optimization problem.
Phase‐Field Simulations of Cracks under Dynamic Loading
Authors: Bilgen Carola , Wieners Christian , Weinberg Kerstin 
Published: November 2019

AbstractPhase‐field fracture simulations have been established to simulate crack propagation in fracture mechanics. This contribution sets the focus on different driving forces for crack growth and on the simulation of waves propagating along the fractured interfaces.Typically, phase‐field methods for brittle fracture employ a variational framework which has been proven to converge to Griffith’ classical model. This approach, however, has limits in the pressure dominated regime. For that reason we propose ad‐hoc driving forces which are motivated physically using general fracture mechanic concepts. Additionally we investigate the effect of the phase‐field modeled cracks and interfaces on the propagation of the arising waves. The accuracy and the robustness of the simulation method will be demonstrated by numerical examples.
Modelling of cellular materials by a microsphere‐based material model
Authors: Jung Anne , Bleistein Thomas , Diebels Stefan 
Published: November 2019

AbstractMetal foams are a very interesting class of cellular materials which, due to their structure, can be used both for lightweight construction and for the absorption of kinetic energy. They have a microheterogeneous structure, which makes it difficult to simulate these materials efficiently. Although microstructure models are very precise in terms of strut size and pore geometry, they are very computationally intensive due to their high resolution and therefore do not allow the simulation of entire components. While continuum models that do not resolve the specific microstructure are very efficient, they do not allow the influence of variations in strut size, strut geometry or pore size to be modelled directly by the simulation. Therefore, simulation approaches such as microsphere models are necessary, which combine the macroscopic component scale with the microscopic microstructure.
Uncertainty Quantification for Optimal Power Flow Problems
Authors: Mühlpfordt Tillmann , Hagenmeyer Veit , Faulwasser Timm 
Published: November 2019

AbstractThe need to de‐carbonize the current energy infrastructure, and the increasing integration of renewables pose a number of difficult control and optimization problems. Among those, the optimal power flow (OPF) problem—i.e., the task to minimize power system operation costs while maintaining technical and network limitations—is key for operational planning of power systems. The influx of inherently volatile renewable energy sources calls for methods that allow to consider stochasticity directly in the OPF problem. Here, we present recent results on uncertainty quantification for OPF problems. Modeling uncertainties as second‐order continuous random variables, we will show that the OPF problem subject to stochastic uncertainties can be posed as an infinite‐dimensional L2‐problem. A tractable reformulation thereof can be obtained using polynomial chaos expansion (PCE), under mild assumptions. We will show advantageous features of PCE for OPF subject to stochastic uncertainties. For example, multivariate non‐Gaussian uncertainties can be considered easily. Finally, we comment on recent progress on a Julia package for PCE.
Science Thriller: The dramatic destiny of Alexander Mohrenstein‐Ertel and the history of elastohydrodynamics
Authors: Popova Elena , Popov Valentin L. 
Published: November 2019

AbstractPresentation is devoted to the life and work of Alexander Mikhailovich Ertel, the founder of elastohydrodynamics. He was the first to recognize the importance of elastic deformation of partners in lubricated contacts as well as pressure dependence of lubricants. In his dissertation written in Moscow during the Second World War, he suggested a solution of this complicated problem, which was not changed essentially by the later research. However, due to his escape to West Germany and change of identity, the real authorship remained unknown over many years. In West Germany, Mohrenstzein‐Ertel continued his work by practical implementation of the ideas suggested in his dissertation. He could reveal his identity after the Stalin's death, and could witness the recognition of his contribution through the German Tribological Society and international tribological community.
Modeling of electric field‐induced magnetization switching in multiferroic heterostructures
Authors: Dornisch Wolfgang , Müller Ralf 
Published: November 2019

AbstractMultiferroic heterostructures consist of materials with either pronounced ferroelectric or ferromagnetic effect. The combination of both types of material, be it in layers, columns or inclusions, potentially yields a significant magneto‐electric coupling effect even at room temperature. The magnetization in the ferromagnetic material can be controlled by the application of electric fields to the ferroelectric material. In this contribution a linear elastic continuum formulation is coupled with a phase field formulation for the polarization and magnetization in the ferroelectric and the ferromagnetic layer, respectively. The strain transfer at the interface of the layers yields a magneto‐electric coupling effect within the heterostructures. The finite element method is used to discretize the arising differential equations. A numerical example provides a proof of concept for the simulation of the magneto‐electric coupling effect in multiferroic heterostructures.