bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamical Modeling and LQR Control of a Gyroscopically Stabilized Bicycle
Authors: Gattringer Hubert , Reiter Alexander , Müller Andreas , Wagner Daniel , Mauernböck Tobias 
Published: December 2018

AbstractThis contribution focuses on the dynamical modeling and control of a self‐balancing bicycle. The bicycle is equipped with two flywheels rotating at constant speed mounted via a hinge that is actuated by an additional motor and allows for rotation about the vertical axis. Due to the balance of angular momentum, a torque is generated around the axis perpendicular to the hinge and spinning axis, i.e. an axis along the forward motion direction. This gyroscopic effect is exploited for the stabilization of the bicycle. Two cases are distinguished: 1) For the stabilization of the non‐moving bicycle an LQ–controller based on a linear model is used. 2) For the moving bicycle, a non‐linear dynamic model in terms of non‐holonomic velocities is derived and based on the linearized model at constant driving speeds the stability of the bicycle is analyzed. The model reveals the self‐stabilization behavior of a bicycle without flywheels. At a speed of about 17km/h, the linearized model has only eigenvalues with negative real parts and is hence stable. Experimental as well as simulation results are presented.
Anisotropic wave dispersion and band‐gaps in mechanical metamaterials via the relaxed micromorphic model
Authors: d'Agostino Marco V. , Madeo Angela , Barbagallo Gabriele , Ghiba I. Dumitrel , Eidel Bernhard , Neff Patrizio 
Published: December 2018

AbstractWe propose a continuum model (the relaxed micromorphic model) to describe band‐gap phenomena in metamaterials.
Modelling and experimental testing of expanded granules as crash‐absorber for double hull ships
Authors: Woitzik Christian , Chaudry Mohsin Ali , Wriggers Peter , Düster Alexander 
Published: December 2018

AbstractIn this contribution, expanded glass granules are investigated, which will be used to increase the crashworthiness in ship construction. Therefore, an experimental setup is presented. This setup represents a simplified side hull structure of a double hull ship. The empty space between the double hull structure can be filled with the granular material which acts as crash absorber.The described experiment will be used to validate the finite element simulation of the penetration of the double hull with the bulbous bow. To model the granules the Mohr‐Coulomb material model is taken advantage of. Based on the experimental data the suitability of the Mohr‐Coulomb model will be discussed.
The research of viscoelastic mechanical behaviour of human periodontal ligament based on stress‐relaxation tests
Authors: Wu Bin , Ma Songyun , Yan Bin , Heider Yousef , Markert Bernd 
Published: December 2018

AbstractIn this paper a dynamic thermomechanical analyzer was used to perform stress‐relaxation tests on human periodontal ligament samples and a viscoelastic model is employed to correlate the test data. The results show that the stress‐strain curves of the three samples can be predicted by the used constitutive model, which uses five parameters. The correction coefficients are larger than 0.99 for all tests, indicating that the five‐parameter viscoelastic model is suitable for describing the viscoelastic behaviour of human periodontal ligament.
Chondrocyte migration in an acellular tissue‐engineered cartilage substitute
Authors: Nachtsheim Julia , Dursun Gözde , Markert Bernd , Stoffel Marcus 
Published: December 2018

AbstractAcellular tissue‐engineered cartilage substitutes are promising replacement materials to mend small focal defects. The underlying therapeutic idea is to initially stabilise the defect zone and in a long‐term manner allowing for remodelling processes towards a hyaline cartilage tissue. Crucial for remodelling processes inside the implant, is the cell migration from the adjacent tissue, which will be assessed in this study.
Wetting phenomena with ALE interface tracking
Authors: Gründing Dirk , Bothe Dieter , Marschall Holger 
Published: December 2018

AbstractAn arbitrary Lagrangian Eulerian (ALE) interface tracking method is applied to multiphase flows involving wetting phenomena. The method is implemented in OpenFOAM and validated for the static shape of a drop deformed by gravity influence. Results for a constant contact angle model are compared to approximate analytic solutions for the limiting cases of vanishing or infinite Eötvös numbers. Results between the two limiting cases are compared to numerical results from literature.
A hybrid stochastic domain decomposition method for partial differential equations with localised possibly rough random data
Authors: Gruhlke Robert , Eigel Martin , Hömberg Dietmar , Drieschner Martin , Petryna Yuri 
Published: December 2018

AbstractThe presence of air voids in adhesive bonds, possible introduced in a manufacturing process, is regarded as one main reason for failure of rotor blades. Building up a model for material with random inclusion, we numerically solve for it with the help of domain decomposition techniques. This introduces a hybrid method which combines advantages of sampling and stochastic Galerkin strategies based on generalized multi‐element polynomial chaos expansion (gHPCE).
From Experiment to Material Parameter Identification
Authors: Hartmann Stefan , Gilbert Rose Rogin 
Published: December 2018

AbstractConstitutive modeling requires the calibration of the constitutive model to experimental data. This calibration is called material parameter identification. Simple experiments lead to specified deformation and stress states, which is not guaranteed in all situation. Thus, finite elements must be drawn on to calculate the deformation state solving the entire boundary‐value problem. There are several basic questions, which must be addressed apart from experiments doable for the material under consideration: first, what optimization technique is suitable? Second, are the material parameters identifiable by the given experiments, and what is the quality of the result? Third, there have been open questions of the connection between engineering and mathematical literature showing that in Engineering Science the procedures have already been developed in Numerical Mathematics. These question will be discussed in this overview.
Optimization Approaches for Durable Reinforced Concrete Structures considering Interval and Stochastic Parameter Uncertainty
Authors: Freitag Steffen , Edler Philipp , Kremer Katharina , Hofmann Michael , Meschke Günther 
Published: December 2018

AbstractThe durability of reinforced concrete structures is dominated by steel reinforcement corrosion and uncertain service loads, which have to be considered in the lifetime oriented structural design. The transport of corrosive substances into the structure is considerably influenced by load induced cracking. The crack width therefore is a major controlling factor for the lifetime of reinforced concrete structures. To improve the design for durability, finite element models in combination with optimization approaches for polymorphic uncertain data are presented. Here, the crack width at the reinforcement layer is used as the optimization objective to be minimized. The structural reliability is treated as a constraint of the optimization task in terms of the accepted failure probability. The concrete covers of the reinforcement layers are chosen as interval design parameters, with midpoints to be optimized and a given radius to take construction imprecision into account. The structural loading, the Young's modulus of concrete and the corresponding tensile strength are considered as stochastic a priori parameters within the optimization, which is solved by a particle swarm optimization approach in combination with an artificial neural network surrogate model. The polymorphic uncertain structural response is computed by a combination of Monte Carlo simulations and optimization‐based interval analysis to consider the stochastic and interval parameters within the optimization task, respectively. An application example demonstrates the performance of the proposed approach.
Stress‐based Finite Element Methods for Sea Ice Dynamics
Authors: Bertrand Fleurianne 
Published: December 2018

AbstractA first‐order system least squares formulation for the sea‐ice dynamics is presented. In addition to the displacement field, the stress tensor is used as a variable. As finite element spaces, standard conforming piecewise polynomials for the displacement approximation are combined with Raviart‐Thomas elements for the rows in the stress tensor. Computational results for a test problem illustrate the least‐squares approach.
Adaptive trust‐region POD for optimal control of the Cahn‐Hilliard equation
Authors: Alff Jan Oke , Gräßle Carmen , Hinze Michael 
Published: December 2018

AbstractWe consider the optimal control problem of a phase field system with distributed control. A reduction of the computational complexity is achieved by a POD‐Galerkin approach where the expensive high‐fidelity PDE systems are replaced by low‐dimensional approximations. The POD basis functions are computed from snapshots which are space‐adapted finite element solutions of the governing equations. Within the trust‐region framework, the accuracy of the surrogate models is controlled in the course of the optimization. In the numerical example we compare the use of a relaxed double‐obstacle free energy with a smooth free energy concerning the influence on the accuracy of the solution and the optimization performance.
Characterization and propagation of uncertainties associated with limited data using a hierarchical parametric probability box
Authors: Hoang Truong‐Vinh , Rosić Bojana , Matthies Hermann G. 
Published: December 2018

AbstractUncertainty of random variables is commonly characterized from measurement data. In practice, data might be insufficient in order to obtain an accurate probability model. In this work, we assume that the type of distribution of the considered random variable is known a priori, and use a hierarchical parametric probability box (p‐box) – which is a set of distributions whose parameters are uncertain – to account for the limited data. Using Bayes' rule, knowledge about the variability of these parameters is updated. Propagation of these uncertainties through a computational model usually suffers from computational burden. A surrogate model approximating the computational model is constructed to reduce computational cost.
Crystallization and flame‐retardant properties of polylactic acid composites with polyhedral octaphenyl silsesquioxane
Authors: Jia Lin , Tong Bin , Li Dinghua , Zhang Wenchao , Yang Rongjie 
Published: December 2018

To develop environmental‐friendly and flame‐retarded polymer composites, bio‐based polylactic acid (PLA) was loaded with thermally stable polyhedral octaphenyl silsesquioxane (OPS). Pure PLA and PLA/OPS composites with the OPS of 1, 3, 5, and 10 wt% were prepared by extrusion and injection molding, respectively. The scanning electron microscopy (SEM), polarized optical microscope (POM), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and thermal gravimetric analysis (TGA) were used to analyze the dispersion of the OPS in the PLA matrix and the effects of OPS on the crystallization and thermal stability properties of PLA/OPS composites, respectively. Limited oxygen index (LOI) and cone calorimeter (CONE) measurements were used to study flame retardancy of PLA and PLA/OPS composites. In order to study the flame‐retardant mechanism, the char residues were investigated by SEM, Fourier transform infrared spectra (FTIR), and X‐ray photoelectron spectroscopy (XPS). TGA‐FTIR was used to analyze the gaseous products of their thermal decomposition. The results show that the OPS particles were submicron in the PLA and could increase the crystallization rate of PLA and form small‐sized secondary α‐form crystalline compared with the pure PLA spherulite. The PLA and OPS decomposed individually in the PLA/OPS composites by TGA. According to the LOI tests, the PLA with the OPS loading exhibited very small reduction of LOI. However, the CONE tests indicated that the OPS could improve the flame retardancy of the PLA by means of low peak heat release rate and average heat release rate. It was obtained that the degree and type of the PLA crystalline for the pure PLA and PLA/OPS affect their flame retardancy. In the max thermal decomposition stage of PLA and PLA/OPS, their gaseous products were similar; at high temperatures, the PLA/OPS produced simple and clear gaseous products of PLA with solid SiO2 in the gas phase.
High performance biocompatible cellulose‐based microcapsules encapsulating gallic acid prepared by inverse microsuspension polymerization
Authors: Tangsongcharoen Wichsuda , Punyamoonwongsa Patchara , Chaiyasat Preeyaporn 
Published: December 2018

AbstractIn this study, the preparation of biocompatible cellulose‐based microcapsules encapsulating gallic acid (GA), an important antioxidant of Bambara groundnut extracts, by water‐in‐oil inverse microsuspension polymerization was studied. GA and carboxymethyl cellulose (CMC) were selected as core and shell materials, respectively. For high encapsulation efficiency, CMC was firstly modified (modified‐CMC (m‐CMC)) with 3‐(trimethoxysilyl)propyl methacrylate (MPS) as a silane coupling agent. It was subsequently polymerized with methacrylic acid (MAA) monomer through a radical route, forming a PMAA grafted m‐CMC (m‐CMC‐g‐PMAA) biocompatible polymer shell. Using CMC:MPS in a ratio of 75:25 (w/w %), highly water‐soluble m‐CMC containing a C=C bond for further radical polymerization was obtained. After inverse microsuspension polymerization at various ratios of m‐CMC:MAA, highly stable spherical m‐CMC‐g‐PMAA microcapsules encapsulating GA were formed in all ratios. It was observed that the encapsulation efficiency increased with increase in MAA content. m‐CMC:MAA in a ratio of 33:67 (w/w%) presented the highest encapsulation efficiency which may due to the increase of hydrophilicity of the aqueous phase. It also presented rapid release and non‐cytotoxic characteristics, suited for use in cosmetic products. © 2018 Society of Chemical Industry
Several phased siRNA annotation methods can frequently misidentify 24 nucleotide siRNA‐dominated PHAS loci
Authors: Polydore Seth , Lunardon Alice , Axtell Michael J. 
Published: December 2018

AbstractSmall RNAs regulate key physiological functions in land plants. Small RNAs can be divided into two categories: microRNAs (miRNAs) and short interfering RNAs (siRNAs); siRNAs are further subdivided into transposon/repetitive region‐localized heterochromatic siRNAs and phased siRNAs (phasiRNAs). PhasiRNAs are produced from the miRNA‐mediated cleavage of a Pol II RNA transcript; the miRNA cleavage site provides a defined starting point from which phasiRNAs are produced in a distinctly phased pattern. 21–22 nucleotide (nt)‐dominated phasiRNA‐producing loci (PHAS) are well represented in all land plants to date. In contrast, 24 nt‐dominated PHAS loci are known to be encoded only in monocots and are generally restricted to male reproductive tissues. Currently, only one miRNA (miR2275) is known to trigger the production of these 24 nt‐dominated PHAS loci. In this study, we use stringent methodologies in order to examine whether or not 24 nt‐dominated PHAS loci also exist in Arabidopsis thaliana. We find that highly expressed heterochromatic siRNAs were consistently misidentified as 24 nt‐dominated PHAS loci using multiple PHAS‐detecting algorithms. We also find that MIR2275 is not found in A. thaliana, and it seems to have been lost in the last common ancestor of Brassicales. Altogether, our research highlights the potential issues with widely used PHAS‐detecting algorithms which may lead to false positives when trying to annotate new PHAS, especially 24 nt‐dominated loci.
Admission Pentraxin‐3 Level Predicts Severity of Community‐Acquired Pneumonia Independently of Etiology
Authors: Luo Qiongzhen , He Xinwei , Ning Pu , Zheng Yali , Yang Donghong , Xu Yu , Shang Ying , Gao Zhancheng 
Published: December 2018

PurposePentraxin‐3 (PTX3) is a nonspecific marker of disease severity; however, PTX3 data from community‐acquired pneumonia (CAP) patients are lacking.Experimental designAn observational, prospective study of CAP patients was conducted in 2016. Plasma PTX3 levels are determined with quantitative ELISA. The primary endpoint is diagnosis of severe CAP (SCAP); the secondary endpoint is hospital mortality or discharge from the hospital.ResultsAmong 188 enrolled patients, 88 are diagnosed with SCAP, and 17 died during the hospital stay. Admission PTX3 levels are higher in patients with high CURB‐65 (confusion, uremia, respiratory rate, blood pressure, age ≥65 years) or Pneumonia Severity Index (PSI) scores (p < 0.0001 for both) and are unaffected by etiology. PTX3 demonstrate good performance in predicting both SCAP in CAP patients (AUC = 0.847) and 30‐day mortality of CAP patients (AUC = 0.796). PTX3 combined with CURB‐65 improve prediction performance (p = 0.0379). Furthermore, multivariate Cox regression analysis confirm ≥33.52 ng mL−1 PTX3 as an independent predictor of 30‐day survival.Conclusions and clinical relevanceAdmission levels of PTX3 are useful for predicting severity of CAP, independent of possible pathogens. PTX3 can improve prognostic accuracy of severity scores. Detection of PTX3 on admission might be useful for clinical judgment.Trial registrationClinicalTrials.gov ID: NCT03093220, Date of registration: March 28, 2017 (retrospectively registered)
A novel triple amino acid substitution in the EPSPS found in a high‐level glyphosate‐resistant Amaranthus hybridus population from Argentina
Authors: Perotti Valeria E , Larran Alvaro S , Palmieri Valeria E , Martinatto Andrea K , Alvarez Clarisa E , Tuesca Daniel , Permingeat Hugo R 
Published: December 2018

AbstractBackgroundThe evolution of herbicide‐resistant weeds is one of the most important concerns of global agriculture. Amaranthus hybridus L. is a competitive weed for summer crops in South America. In this article, we intend to unravel the molecular mechanisms by which an A. hybridus population from Argentina has become resistant to extraordinarily high levels of glyphosate.ResultsThe glyphosate‐resistant population (A) exhibited particularly high parameters of resistance (GR50 = 20 900 g ai ha−1, Rf = 314), with all plants completing a normal life cycle even after 32X dose application. No shikimic acid accumulation was detected in the resistant plants at any of the glyphosate concentrations tested. Molecular and genetic analyses revealed a novel triple substitution (TAP‐IVS: T102I, A103V, and P106S) in the 5‐enol‐pyruvylshikimate‐3‐phosphate synthase (EPSPS) enzyme of population A and an incipient increase on the epsps relative copy number but without effects on the epsps transcription levels. The novel mechanism was prevalent, with 48% and 52% of the individuals being homozygous and heterozygous for the triple substitution, respectively. In silico conformational studies revealed that TAP‐IVS triple substitution would generate an EPSPS with a functional active site but with an increased restriction to glyphosate binding.ConclusionThe prevalence of the TAP‐IVS triple substitution as the sole mechanism detected in the highly glyphosate resistant population suggests the evolution of a new glyphosate resistance mechanism arising in A. hybridus. This is the first report of a naturally occurring EPSPS triple substitution and the first glyphosate target‐site resistance mechanism described in A. hybridus. © 2018 Society of Chemical Industry
Enhancing the performance of the EWMA control chart for monitoring the process mean using auxiliary information
Authors: Adegoke Nurudeen A. , Abbasi Saddam Akber , Dawod Abdaljbbar B.A. , Pawley Matthew D.M. 
Published: December 2018

AbstractWhen using control charts to monitor manufacturing processes, the exponentially weighted moving average (EWMA) control chart is useful for detecting persistent shifts in the process parameter. This paper proposes enhancements to the applications of the EWMA control chart for those scenarios where the exact measurement of process units is difficult and expensive, but the visual ordering of the units can be done easily. The proposed charts use an auxiliary variable that is correlated with the process variable to provide efficient monitoring of shifts in the process mean and are formulated based on ranked set sampling (RSS) and median RSS schemes (MRSS). Simulation results showed that the proposed charting schemes are more efficient in detecting a shift in the process mean than the classical EWMA control chart and its modification. An example is provided to show the application of the proposed charts using a simulated benchmark process: the continuous stirred tank reactor (CSTR).
Systematic review of ganciclovir pharmacodynamics during the prevention of cytomegalovirus infection in adult solid organ transplant recipients
Authors: Wong Diana D. , van Zuylen Wendy J. , Craig Maria E. , Rawlinson William D. 
Published: December 2018

SummaryHuman cytomegalovirus (CMV) represents the most common infection among recipients of solid organ transplants (SOTs). Previous meta‐analysis showed 0.8% of SOT recipients developed CMV disease whilst receiving valganciclovir (ValGCV) prophylaxis. However, the clinical utility of monitoring ganciclovir (GCV) blood concentrations is unclear. We systematically reviewed the association between GCV concentrations during prophylaxis and the incidence of CMV. MEDLINE and EMBASE databases were searched for studies between 1946 and 2018, where GCV pharmacokinetics and incidence of CMV viraemia or disease in SOT were available. Research designs included randomised trials, comparative, prospective cohort, retrospective, or case report studies. Only human adult studies were included, with English language restriction. The 11 studies that met the eligibility criteria included 610 participants receiving GCV or ValGCV prophylaxis. Quality assessment showed 2/4 randomised trials, 4/6 cohort studies, and 1/1 case report were of high quality. Despite dose adjustments for renal impairment, mean GCV exposures for patients were heterogeneous and ranged between 28 and 53.7 μg·h/mL across three randomised trials. The incidence of CMV infection and disease ranged from 0% to 50% and 0% to 3.1%, respectively, with follow up between 3 to 9 months. One study showed statistical power in determining relationship, where GCV exposure at 40 to 50 μg·h/mL in high‐risk SOT recipients was associated with a reduced risk of viraemia. Clinical monitoring for GCV exposure can be applied to high‐risk SOT recipients during ValGCV prophylaxis; however, further studies are needed to determine the utility of monitoring in all SOT recipients.