bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solar‐Thermal Energy Conversion and Storage Using Photoresponsive Azobenzene‐Containing Polymers
Authors: Wu Si , Butt Hans‐Jürgen 
Published: November 2019

AbstractPhotoswitchable compounds are promising materials for solar‐thermal energy conversion and storage. In particular, photoresponsive azobenzene‐containing compounds are proposed as materials for solar‐thermal fuels. In this feature article, solar‐thermal fuels based on azobenzene‐containing polymers (azopolymers) are reviewed. The mechanism of azopolymer‐based solar‐thermal fuels is introduced, and computer simulations and experimental results on azopolymer‐based solar‐thermal fuels are highlighted. Different types of azopolymers such as linear azopolymers, 2D azopolymers, and conjugated azopolymers are addressed. The advantages and limitations of these azopolymers for solar‐thermal energy conversion and storage, along with the remaining challenges of azopolymer‐based solar‐thermal fuels, are discussed.
Effect of Streptomyces probiotics on the gut microbiota of Litopenaeus vannamei challenged with Vibrio parahaemolyticus
Authors: Mazón‐Suástegui José Manuel , Salas‐Leiva Joan Sebastian , Medina‐Marrero Ricardo , Medina‐García Ricardo , García‐Bernal Milagro 
Published: November 2019

AbstractThis study assessed the intestinal microbiota of juveniles of the White shrimp Litopenaus vannamei, whose feed was enriched with three probiotic formulations: Streptomyces sp. RL8 (RL8); a mix of Lactobacillus graminis and Streptomyces spp. RL8 and N7 (Lac‐Strep); and a mix of Bacillus spp. and Streptomyces spp. RL8 and N7 (Bac‐Strep). The analysis was performed by sequencing the V3 region of the 16S rRNA gene of treated animals and the control group before and after Vibrio parahaemolyticus challenge. After challenge, the highest Shannon diversity indexes corresponded to RL8 and Bac‐Strep (3.94 ± 0.11 and 3.39 ± 0.3, respectively) and the lowest to the control group (2.58 ± 0.26). The most abundant phyla before and after challenge were Proteobacteria, Actinobacteria, and Bacteroidetes. The principal component analysis and Statistical Analysis of Metagenomic Profiles (STAMP) showed that the gut microbiota of the groups RL8 and Bac‐Strep after challenge was different from the other experimental groups, which was characterized by a higher bacterial diversity, as well as a significant stimulation of the Bacteriovorax population and other antimicrobial producing genera that protected shrimp from infection.
The alteration of PLCζ protein expression in unexplained infertile and asthenoteratozoospermic patients: A potential effect on sperm fertilization ability
Authors: Rahimizadeh Pegah , Topraggaleh Tohid Rezaei , Nasr‐Esfahani Mohammad Hossein , Ziarati Niloofar , Mirshahvaladi Shahab , Esmaeili Vahid , Seifi Soroush , Eftekhari‐Yazdi Poopak , Shahverdi Abdolhossein 
Published: November 2019

AbstractFailed oocyte activation has been observed in unexplained infertile (UI) and asthenoteratozoospermic (AT) men. The deficiency of phospholipase C‐zeta (PLCζ) could be a possible reason for such failures and has not been studied yet. We investigated the expression and localization of PLCζ protein in the sperms of patients with UI and AT conditions. The relationships between PLCζ‐related parameters with male age, sperm characteristics, DNA integrity, and cellular maturity were assessed. Semen samples were collected from fertile (n = 40), UI (n = 40), and AT (n = 40) men. Subsequently, semen analysis, DNA fragmentation, hyaluronic acid‐binding ability, and PLCζ level along with its distribution were evaluated using computer‐assisted sperm analyzer, sperm chromatin structure assay (SCSA), hyaluronic acid‐binding assay (HBA), western blot analysis and immunofluorescence microscopy, respectively. Unlike SCSA, the values of HBA, and PLCζ expression were significantly reduced in UI and AT patients compared to fertile men, whereas no significant differences were observed among the experimental groups in terms of PLCζ localization patterns. The regression analysis also showed that HBA is the only variable associated with PLCζ levels. Furthermore, the correlation of male age with PLCζ localization in postacrosomal, equatorial, and acrosomal+postacrosomal+equatorial (A+PA+E) patterns, as well as the relation of normal morphology, with the (A+PA+E) pattern, remained in the regression model. Our findings indicated that reduced PLCζ level along with the increased DNA fragmentation and impaired maturation may be possible etiologies of decreased fertilization in the studied subjects.
A conversation with Mariana Wolfner, newly inducted member of the National Academy of Sciences
Authors: Swanson Willie J. , Findlay Geoffrey D. 
Published: November 2019

AbstractMolecular Reproduction and Development is delighted to announce that editorial board member Mariana F. Wolfner has been elected to the National Academy of Sciences. Here, Dr Wolfner is interviewed by two of her former postdocs. She discusses her path to studying reproduction and her career as a researcher and mentor.
Four‐dimensional translabial ultrasound concordance with digital palpation and surface electromyography during dynamic pelvic floor muscles assessment: A cross‐sectional study
Authors: Martinho Natalia , Botelho Simone , Nagib Anita , Jales Rodrigo Menezes , Turel Friyan , Caagbay Delena , Riccetto Cássio 
Published: November 2019

AbstractAimTo investigate whether pelvic floor muscle (PFM) morphological changes obtained through four‐dimensional translabial ultrasound (4D TLUS) correlate with a PFM contraction as evaluated by digital palpation and PFM electromyographic activity evaluated by surface electromyography (sEMG). The secondary objective was to investigate which ultrasound parameter is more strongly associated with digital palpation.MethodsThis cross‐sectional study included 210 women and their PFMs were evaluated by digital palpation (graded according to the Modified Oxford Scale), sEMG and 4D TLUS. Offline analysis of ultrasound volume datasets was performed for measuring the change in levator plate angle, bladder neck elevation, hiatal area narrowing, puborectalis strain, and puborectalis muscle thickness at rest and during PFM contraction. Statistical analysis included Kruskal‐Wallis, Dunn, and Spearman's tests in addition to univariate and multivariate logistic regression, adopting a significance level of 5%.ResultsA weak but significant correlation between the change in levator plate angle and sEMG (P = .04; r = 0.14) was found. All 4D TLUS measurements, except the puborectalis muscle thickness, significantly correlated with digital palpation (P < .0001); with the puborectalis strain and the change in levator plate angle having the strongest combined parameters associated with digital palpation (R2 = 21.77%), despite the low coefficient of determination.ConclusionWe found that 4D TLUS significantly correlates with digital palpation and sEMG, being the change in the levator plate angle the parameter that best correlates with both methods. While digital palpation is essential during a PFM functional assessment, 4D TLUS is recommended as a beneficial noninvasive clinical tool for a more in‐depth evaluation.
What criteria affect a patient's choice of catheter for self‐catheterization?
Authors: Hentzen Claire , Turmel Nicolas , Chesnel Camille , Miget Gabriel , Le Breton Frederique , Charlanes Audrey , Tan Eliane , Amarenco Gérard 
Published: November 2019

AbstractAimThe aim was to determine which criteria are most influential in guiding the patient's choice of catheter during clean intermittent self‐catheterization (CISC) education.MethodsA questionnaire exploring five traits (catheter design, catheter length, the comfort of use, nurse's explanations, and how easy it was to carry and dispose of the catheter) was administered to all patients who succeeded in performing CISC. The patients had to report the criterion that most influenced their choice, and rate the importance of each criterion from 1 to 4 on a Likert scale (strongly disagree, somewhat disagree, somewhat agree, strongly agree). The study assessed the impact that age, sex, etiology, dependency, motor or sensory upper limb deficiency, and position required to perform CISC may have had on the importance of the different criteria.ResultsSeventy‐three patients were included (mean age, 50.9 ± 14.3 years). The most important criterion was the nurse's explanations (44%), followed by comfort of handling (32%), the discreet aspect of carrying the catheter (15%), and catheter length (7%). The esthetic aspect was not important for 34% of patients, whereas all the other criteria were important for at least 82% of patients. The comfort of handling was more often a priority for those with motor or sensory upper limb disorders (P < .01). The other characteristics of the patients did not impact the way they prioritized the criteria.ConclusionThese results highlight the importance of extensive training for nurses involved in CISC education, as their explanations have the greatest impact on the patient's choice of the catheter.
Well‐posedness and finite element approximation of time dependent generalized bioconvective flow
Authors: Cao Yanzhao , Chen Song , van Wyk Hans‐Werner 
Published: November 2019

AbstractWe consider the finite element approximation of a time dependent generalized bioconvective flow. The underlying system of partial differential equations consists of incompressible Navier–Stokes type convection equations coupled with an equation describing the transport of micro‐organisms. The viscosity of the fluid is assumed to be a function of the concentration of the micro‐organisms. We show the existence and uniqueness of the weak solution of the system in two dimensions and construct numerical approximations based on the finite element method, for which we obtain error estimates. In addition, we conduct several numerical experiments to demonstrate the accuracy of the numerical method and perform simulations of the bioconvection pattern formations based on realistic model parameters to demonstrate the validity of the proposed numerical algorithm.
On the regularization for ductile damage models
Authors: Langenfeld Kai , Möhring Kerstin , Walther Frank , Mosler Jörn 
Published: November 2019

AbstractModeling softening behavior often leads to ill‐posed boundary value problems. This, in turn, results in pathological mesh‐dependent computations as far as the finite‐element‐method is concerned. A by now widely used technique to eliminate these problems is the micromorphic approach by [1,2]. This regularization technique implicitly includes gradients of internal variables into the constitutive model. However, and in contrast to other gradient‐enhanced models, the micromorphic approach preserves the local structure of the underlying local constitutive model. Within this contribution, it is first shown that a standard application of this approach to ductile damage models does not work. By analyzing the respective equations, a modification of the regularization technique is elaborated – first for an isotropic ductile damage model, i.e. scalar‐valued damage. Subsequently, the novel regularization is extended to tensor‐valued damage models.
On Empirical System Gramians
Authors: Grundel Sara , Himpe Christian , Saak Jens 
Published: November 2019

AbstractState‐space realizations of input‐output systems or control systems are a widely used class of models in engineering, physics, chemistry and biology. For the qualitative and quantitative classification of such systems, the system‐theoretic properties of reachability and observability are essential, which are encoded in so‐called system Gramian matrices. For linear systems these Gramians are computed as solutions to matrix equations, for nonlinear or parametric systems the data‐driven empirical system Gramians approximate the actual system Gramians. These empirical Gramians have manifold applications, for example in model reduction or decentralized control of nonlinear systems, as well as sensitivity analysis, parameter identification and combined state and parameter reduction of parametric systems. Here, we demonstrate that empirical system Gramians are also useful for linear but hyperbolic input‐output systems.
Kinematic hardening and Bauschinger effect
Authors: Tran Tuan Minh , Le Khanh Chau 
Published: November 2019

AbstractThis paper studies a single crystal subjected to anti‐plane shear‐controlled load reversal within the thermodynamic dislocation theory. Numerical simulations of the governing equations demonstrate the size‐dependent kinematic hardening and the Bauschinger effect. Both are caused by the excess dislocations.
High‐Order Numerical Methods for the Thermal Activation of SMA Fibers
Authors: Gleim Tobias , Kuhl Detlef , Schleiting Maximilian , Wetzel Alexander , Middendorf Bernhard 
Published: November 2019

AbstractThe present paper establishes an axisymmetric benchmark model of a conducting loop, which implies an electromagnetic induction. Therein, the MAXWELL equations are demonstrated in a direct formulation (without a potential formulation) with its solution strategy. Standard high‐order LAGRANGE shape functions and a harmonic ansatz are used to solve the electromagnetic behavior. Studies regarding the influence of a steel fiber in a block of concrete are analyzed.
Non‐localized Contact Between Beams with Non‐Circular Cross Sections
Authors: Magliulo Marco , Zilian Andreas , Beex Lars 
Published: November 2019

AbstractIn this contribution, we introduce a contact formulation between beams finite elements with (hyper)elliptical cross sections. The contact scheme allows to model scenarios in which the contact area is finite or the contact area occurs along a line. Although some contact schemes are yet able to do this, they require one of the beams to have a circular cross section [1, 2]. Here however, we focus on non‐circular cross‐sections. Consequently, new projections are required, in which the beam surfaces are used explicitly to formulate contact kinematics.
Model reduction techniques for port‐Hamiltonian differential‐algebraic systems
Authors: Hauschild Sarah-Alexa , Marheineke Nicole , Mehrmann Volker 
Published: November 2019

AbstractPort‐based network modeling of multi‐physics problems leads naturally to a formulation as port‐Hamiltonian differential‐algebraic systems (pHDAEs). In this way, the physical properties are directly encoded in the structure of the model. Since the state space dimension of such systems may be very large, in particular when the model is a space‐discretized partial differential‐algebraic system, in optimization and control there is a need for model reduction methods that preserve the port‐Hamiltonian (pH) structure while keeping the algebraic constraints unchanged. To combine model reduction for differential‐algebraic equations (DEAs) with port‐Hamiltonian structure preservation, we adapt power conservation based techniques from port‐Hamiltonian systems of ordinary differential equations (pHODEs) to pHDAEs. The performance of the methods is investigated for benchmark examples originating from semi‐discretized flow problems.
Funnel control for linear non‐minimum phase systems
Authors: Berger Thomas 
Published: November 2019

AbstractWe consider tracking control for linear non‐minimum phase systems with known relative degree. For a given reference signal we design a low‐complexity controller which achieves that the tracking error evolves within a prescribed performance funnel. We present a novel approach where a new output is constructed, with respect to which the system has a higher relative degree, but the unstable part of the internal dynamics is eliminated. Using recent results in funnel control, we then design a controller for this new output, which also incorporates a new reference signal. The original output stays within a prescribed performance funnel around the original reference trajectory and all signals in the closed‐loop system are bounded.
Application of a mixed variational higher order plate theory towards understanding the deformation behavior of hybrid laminates
Authors: Jackstadt Alexander , Liebig Wilfried V. , Sessner Vincent , Weidenmann Kay A. , Kärger Luise 
Published: November 2019

AbstractHybrid laminates containing an elastomer layer in addition to fiber reinforced polymer as well as metal layers have been found beneficial in compensating issues frequently found with traditional fiber metal laminates. Commonly used equivalent single‐layer shell and plate theories, however, are unable to account for the strong heterogeneous stiffness distribution of the constituents within the laminate. Furthermore, the transverse shear and normal deformations in the elastomer layer are expected to significantly influence the deformation of the neighboring laminae. An accurate depiction of these transverse stresses requires a multi‐layer shell theory as opposed to commonly used single‐layer formulations. Hence, a higher order mixed variational plate theory is applied in order to study and predict the mechanical behavior of such laminates, especially on a structural level where the computational effort forbids the use of a three dimensional continuum formulation.
Towards the incorporation of damage into solid‐shells based on reduced integration
Authors: Barfusz Oliver , Brepols Tim , Frischkorn Jan , Reese Stefanie 
Published: November 2019

AbstractSome years ago, a family of continuum finite elements based on reduced integration [1], [2], [3] was investigated. Many structural components with different kinds of elastic and inelastic material behaviour were considered and these elements showed accurate results while beeing more efficient than similar three‐dimensional formulations based on full integration. The objective of the present contribution is to extend the analysis to damage and fracture. To this end, we present the incorporation of a modified version of a gradient‐extended damage model [4] based on the micromorphic approach [5] into solids with only a single integration point. Due to the analogy to fully‐coupled thermomechanical problems, we adapt the derivation of a consistent hourglass stabilization from an earlier contribution for multi‐field problems [6]. A numerical benchmark problem of quasi‐brittle fracture reveals the accuracy and efficiency of the proposed approach. Besides the ability to deliver mesh‐independent results, the framework is especially suitable for highly constrained situations in which conventional low‐order finite elements suffer from well known locking phenomena.
Effect of a rotating magnetic field on the decay of a free‐falling metal jet
Authors: Kasper Tom , Schwarze Rüdiger 
Published: November 2019

AbstractAdditive manufacturing enables the production of individualized high‐grade components. Established techniques can use metal powder as its basic material. The generated product is often limited by the particle size distribution, particle shapes, and its composition. The metal powder manufacturing process needs to be understood and improved to enhance the quality of the fabricated products. In this work, numerical simulations are performed to describe the flow processes of powder production using the method of free‐falling gas atomization. Furthermore, the use and influence of a rotating magnetic field is adapted to the atomization process and investigated by varying the influencing parameters like magnetic field strength and rotational frequency.
Effects of fluid rheology and wetting properties on the droplet motion by a shear flow
Authors: Barwari Beawer , Burgmann Sebastian , Rohde Martin , Janoske Uwe 
Published: November 2019

AbstractThe paper presents an experimental investigation of the detaching mechanisms of adhering droplets exposed to a turbulent air flow, focusing on the specific case of water, glycerine and ethanol droplets on a PMMA and coated silicon wafer surface. A rectangular Plexiglas channel (22 x 22 mm) with a replaceable substrate is used. A controlled air flow is established and increased during the experiment, until the droplet deforms and starts to move from its initial position along the surface. Shadowgraph technique is applied to measure the droplet behavior. The images are automatically analyzed by an edge‐detection algorithm to gain information on the droplet contour, the contact angles and the contact line movement. It was found that the critical velocity required for the onset of the droplet movement decreases with the droplet volume. As the viscosity of the droplet increases, the critical velocity increases. For a particular liquid it is easier to detach the droplets on coated silicon wafers compared to PMMA due to the increase of the hydrophobicity of the substrate. Glycerine droplets move at a slow rate over the surface due to the high viscous damping and reach a certain position only at higher air velocities. The results show that contact angle hysteresis seems not to be the unique factor influencing the critical velocity, since several parameters superpose and affect the droplet detachment process.
Coordinate‐Invariant Linear Quadratic Control
Authors: Burnett Ethan R. , Sinclair Andrew J. , Butcher Eric A. 
Published: November 2019

AbstractThis paper shows how the linear quadratic regulator (LQR) designs in different coordinate choices are related. Given the LQR design in one coordinate choice, it is shown that the LQR design for an alternate coordinate choice can be recovered through use of the nonlinear and linearized coordinate transformations. This provides the analyst a method of comparing coordinate choices that is more straightforward than previously suggested methods involving nonlinearity indices.
A closed‐form analytical approach for stress concentrations at elliptical holes in moderately thick plates
Authors: Felger Julian , Becker Wilfried 
Published: November 2019

AbstractIn this work, a modified plate model situated in‐between the classical Kirchhoff‐Love and first‐order shear deformation plate theory (FSDT) is proposed. The modified plate model includes transverse shear deformation and the governing system of partial differential equations can be tackled employing a complex potential approach. This allows for using the powerful tool of conformal mapping enabling closed‐form analytical solutions on complex domains. Based on the established complex potential methodology, the distribution of bending moments at an elliptical hole in an infinite plate under bending loading is derived. Solutions of the modified plate model are compared against numerical reference data employing FSDT.
On the Lubricant Flow and the Friction Coefficient in Partially Filled Gaps
Authors: Stahl Lukas , Müller Michael , Ostermeyer Georg-Peter 
Published: November 2019

AbstractStarved lubrication is a friction regime in which the gap between the contact partners is not fully filled with fluid. It can serve as an important strategy for minimizing the amount of lubricant needed, and also inevitably occurs during idling and fail‐safe lubrication. In this regime, however, the flow of the lubricant and the related friction coefficients are yet to be fully understood. Strong non‐linear behaviour, transient influences and experimental limitations exist and hamper the creation of a comprehensive theory. This paper aims to make a fundamental contribution to the understanding of contact mechanics of partially lubricated contacts. A unique experimental setup with macroscopic asperities has been used to study the lubricant flow, the coefficient of friction (COF), and other variables over a wide range of parameters. Distinct friction behaviours were observed, for example the typical characteristic of the Stribeck curve. In addition to this well documented behaviour the experiments show a similar Stribeck‐like behaviour regarding the lubricant filling level in the gap. This proves and quantifies the expected fact that the friction regime can also be controlled by the fluid volume in the gap. To investigate this behaviour the fluid was evaluated with still images from the experiments. This study exhibits distinct flow patterns for different friction regimes of starved lubrication.