bluuebunny/crossref_metadata_2025 huggingface dataset:
Extended hypoplastic model incorporating the coordination number for the simulation of granular flow
Authors: Leon Bal Abdiel , Dang Thai Son , Meschke Günther
Published: November 2019

In this contribution, a hypoplastic viscous soil model incorporating viscous and grain‐inertia rate effects observed in granular flows is enhanced by means of the coordination number, which allows to characterize the evolution of the microstructure of the granular material. Near a critical solid volume fraction and critical coordination number there exists a transition from a solid‐like (rate‐independent) to a flow‐like (rate‐dependent) behavior of granular materials. This information is used to calibrate a so‐linear concentration factor, which controls viscous and grain‐inertial rate effects in terms of the rate dependent evolution of the coordination number. The influence of this proposed hypoplastic model considering the coordination number is investigated in this paper by means of a simple undrained shear test .
Simulating electromechanical delay across the scales – relating the behavior of single sarcomers on a sub‐cellular scale and the muscle‐tendon system on the organ scale
Authors: Schmid Laura , Klotz Thomas , Siebert Tobias , Röhrle Oliver
Published: November 2019

The time lag between the activation of a muscle and the development of force is commonly denoted as electromechanical delay (EMD). Within this work, a multi‐scale model of an idealized muscle‐tendon system is used to analyze EMD on different characteristic anatomical length scales. Thereby, the simluated EMD‐stretch curves for a complete muscle‐tendon system and a single sarcomere are significantly different. While for an isolated muscle EMD is shown to be strongly determined by excitation‐contraction coupling (ECC), the EMD‐stretch curve for a complete muscle‐tendon system is influenced by additional factors, such as, e.g., the tendon. Further, it is shown that the action potential conduction velocity (APCV) has minor influence on EMD.
Simulation of Dual‐Phase Steel Using the Finite Cell Method and Voxel‐Based Microstructure Data
Authors: Fangye Yannick F. , Miska Niklas , Balzani Daniel
Published: November 2019

For the modeling of micro‐heterogeneous materials, the effective macroscopic response can be determined by means of computational homogenization. The complex morphology of the microstructure needs to be discretized efficiently for numerical simulations. To reduce the effort arising from the generation of a conforming finite element mesh the finite cell method is applied. In this contribution, we focus on the microstructure of dual‐phase steel given by voxel‐based data and present an approach that directly exploits such data for an efficient generation of an integration mesh.
Dynamics of finite‐dimensional mechanical systems on Galilean manifolds
Authors: Capobianco Giuseppe , Winandy Tom , Eugster Simon R.
Published: November 2019

As 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

The 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

The 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

Flow 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

Waveform‐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

We 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

The 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

MRI (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

We 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

There 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

The 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

The 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

Magneto‐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

This 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

Metastable 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

Multi‐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

The 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

Polyelectrolytic 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

In 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

Corticosteroids 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

Hexakis (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

An 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

Two 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

For 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.
The Atomic Structure of Ultrathin Oxide Films and Interfaces Studied by Surface X‐Ray Diffraction
Authors: Mohseni Katayoon , Meyerheim Holger L.
Published: November 2019

X‐ray diffraction (XRD) studies of the atomic structure of ultrathin oxide films and interfaces are presented, which are conducted within the framework of the Sonderforschungsbereich 762 (functionality of oxide interfaces). Knowledge of the atomic structure is at the heart of the study of functional oxides. XRD allows the investigation of complex systems frequently encountered in oxide systems (large unit cells, complex relaxation patterns, and structural and chemical disorder). Results are combined with first‐principles calculations and complementary techniques providing a thorough understanding of the oxides' functionality. The structure analysis of the approximant (AP) to the 2D oxidic quasicrystal (QC) based on BaTiO3 (BTO) is discussed, the first oxide‐type QC discovered. This AP is related to the Kepler tiling described 400 years ago. The LaFeO3/SrTiO3 interface is examined, which is a prototype for the formation of a 2D electron gas (2DEG). Subtle interfacial chemical roughness in combination with oxygen off‐stoichiometry strongly influences the critical LaFeO3 thickness for the 2DEG formation. Finally, the analysis of the multiferroic BTO/ME(001) (ME = Fe, Pd, Pt) interface reveals that a submonolayer of impurities is the origin for the inversion of the BTO film/vacuum termination from BaO on Fe(001) to TiO2 on Pt(001).
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

High‐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.
Highly Efficient and Bright Inverted Top‐Emitting InP Quantum Dot Light‐Emitting Diodes Introducing a Hole‐Suppressing Interlayer
Authors: Lee Taesoo , Hahm Donghyo , Kim Kyunghwan , Bae Wan Ki , Lee Changhee , Kwak Jeonghun
Published: November 2019

InP quantum dots (QDs) based light‐emitting diodes (QLEDs) are considered as one of the most promising candidates as a substitute for the environmentally toxic Cd‐based QLEDs for future displays. However, the device architecture of InP QLEDs is almost the same as the Cd‐based QLEDs even though the properties of Cd‐based and InP‐based QDs are quite different in their energy levels and shapes. Thus, it is highly required to develop a proper device structure for InP‐based QLEDs to improve the efficiency and stability. In this work, efficient, bright, and stable InP/ZnSeS QLEDs based on an inverted top emission QLED (ITQLED) structure by newly introducing a “hole‐suppressing interlayer” are demonstrated. The green‐emitting ITQLEDs with the hole‐suppressing interlayer exhibit a maximum current efficiency of 15.1–21.6 cd A−1 and the maximum luminance of 17 400–38 800 cd m−2, which outperform the recently reported InP‐based QLEDs. The operational lifetime is also increased when the hole‐suppressing interlayer is adopted. These superb QLED performances originate not only from the enhanced light‐outcoupling by the top emission structure but also from the improved electron–hole balance by introducing a hole‐suppressing interlayer which can control the hole injection into QDs.
Investigation of Binary Metal (Ni, Co) Selenite as Li‐Ion Battery Anode Materials and Their Conversion Reaction Mechanism with Li Ions
Authors: Park Gi Dae , Yang Sung Jin , Lee Jong‐Heun , Kang Yun Chan
Published: November 2019

Highly efficient anode materials with novel compositions for Li‐ion batteries are actively being researched. Multicomponent metal selenite is a promising candidate, capable of improving their electrochemical performance through the formation of metal oxide and selenide heterostructure nanocrystals during the first cycle. Here, the binary nickel–cobalt selenite derived from Ni–Co Prussian blue analogs (PBA) is chosen as the first target material: the Ni–Co PBA are selenized and partially oxidized in sequence, yielding (NiCo)SeO3 phase with a small amount of metal selenate. The conversion mechanism of (NiCo)SeO3 for Li‐ion storage is studied by cyclic voltammetry, in situ X‐ray diffraction, ex situ X‐ray photoelectron spectroscopy, in situ electrochemical impedance spectroscopy, and ex situ transmission electron microscopy. The reversible reaction mechanism of (NiCo)SeO3 with the Li ions is described by the reaction: NiO + CoO + xSeO2 + (1 ‐ x)Se + (4x + 6)Li+ + (4x + 6)e− ↔ Ni + Co + (2x + 2)Li2O + Li2Se. To enhance electrochemical properties, polydopamine‐derived carbon is uniformly coated on (NiCo)SeO3, resulting in excellent cycling and rate performances for Li‐ion storage. The discharge capacity of C‐coated (NiCo)SeO3 is 680 mAh g−1 for the 1500th cycle when cycled at a current density of 5 A g−1.
Utilization of blockchain for mitigating the distributed denial of service attacks
Authors: Singh Rajeev , Tanwar Sudeep , Sharma Teek Parval
Published: November 2019

Distributed Denial of Service (DDoS) attacks cause devastating effects on the web services and hence harm the digital availability. The DDoS attackers use vulnerabilities exposed through new networking technologies like wireless, mobile, IoT, and associated protocol weaknesses for bringing down the networks and servers. Owing to availability of easily available tools and botnet armies, the DDoS attack incidences in the internet world are increasing day by day. Several techniques have been proposed by the researchers against DDoS attacks. This paper concentrates on the utilization of one of the latest and most promising technologies, that is, blockchain technology against DDoS attacks. The blockchain technology is rapidly finding use in various applications ranging from financial to gaming; this is because of its stable, decentralized, and secure architecture. The DDoS solutions based on blockchain are still in infancy and some solutions provide only architectural details without bothering about the implementation details. This paper presents a study of the blockchain‐based DDoS solutions. It also compares the existing blockchain‐based techniques against DDoS attacks and analyses them. This paper facilitates the development of future research proposals in this emerging area of blockchain technology.
A privacy‐preserving Blockchain with fine‐grained access control
Authors: Adams Carlisle
Published: November 2019

This article proposes a simple, efficient, and easy‐to‐use mechanism to add privacy and fine‐grained access control features to a traditional Blockchain. It uses standard cryptographic algorithms and techniques, along with a novel key derivation algorithm and a fuzzy extractor component (that derives a cryptographic key from a biometric), to make access control functionality very simple for nonexpert users. Such a Blockchain would be suitable for the storage of participant data postings in long‐term–isolated environments.
Optimization of an Extrusion Cooking Process to Increase Formation of Resistant Starch from Corn Starch with Addition of Citric Acid
Authors: Neder‐Suárez David , Amaya‐Guerra Carlos Abel , Pérez‐Carrillo Esther , Quintero‐Ramos Armando , Mendez‐Zamora Gerardo , Sánchez‐Madrigal Miguel Ángel , Barba‐Dávila Bertha Alicia , Lardizábal‐Gutiérrez Daniel
Published: November 2019

Effects of extrusion cooking process (ECP) with citric acid (CA) addition on the physicochemical changes and resistant starch (RS) formation in native corn starch (NCS) are evaluated. NCS at different feed moisture levels (18–32%) and CA concentrations (0–10.3%), are subject ECP under constant conditions of screw speed (233 rpm) and die temperature (127 °C). The obtained extrudates are stored at 4 °C for 120 h and then at room temperature. The water absorption index (WAI), water solubility index (WSI), RS content, peak temperature (Tp), ∆H, peak viscosity (PV), setback viscosity (SV), FT‐IR, X‐ray analysis and microstructural (SEM) properties are evaluated. RS content and WSI increased with decreasing moisture content (MC), WAI, PV and SV shows that increases in MC caused an increase, while ∆H and Tp decreases with decreasing MC. SEM shows that ECP with CA destroys the granular structure of NCS generated amorphous structures owing to gelatinization and dextrinization. FT‐IR analysis shows that extruded samples with CA cause starch hydrolysis, increasing the intensity of bands 994 and 1016 cm−1 in comparison to NCS. The highest RS yield (1.15 g/100 g) is obtained at 18% moisture content and 5.2% of CA: an increase of 71% with respect to NCS.
Experimental investigations on the effects of the steel rebar corrosion at structural level
Authors: Imperatore Stefania , Rinaldi Zila , Spagnuolo Simone
Published: November 2019

The paper presents some of the results obtained in the framework of a wide research program funded by the Italian Ministry of Instruction and Research, on the corrosion effects on existing structures. Both the aspects related to ultimate and serviceability states are analyzed. In particular, in the first case, the study is devoted to the definition of constitutive relationships of the steel rebars subjected to the corrosion. Many studies are available in literature on this topic, mainly with reference to the tensile behavior; the compressive one is generally neglected. The compressive and buckling behavior of corroded steel bar is discussed in this article with reference to experimental test results, and the importance of accounting for this peculiar aspect is motivated. Finally, with reference to serviceability states and based on tensile tests on reinforced concrete ties, the influence of corrosion on bond transfer length and crack pattern, due to low corrosion amount, not affecting the local and global strength, is clearly shown.
Triple‐chromosome genetic algorithm for unrelated parallel machine scheduling under time‐of‐use tariffs
Authors: Kurniawan Bobby , Chandramitasari Widyaning , Gozali Alfian Akbar , Weng Wei , Fujimura Shigeru
Published: November 2019

Energy demand is increasing as the population and economy grow. Many countries have implemented time‐of‐use (TOU) tariffs to meet such demand so that the demand during peak periods could be reduced by shifting its usage from peak periods to off‐peak periods. This paper addresses the unrelated parallel machine scheduling under TOU to minimize the sum of weighted makespan and electricity cost. Because the problem has nonregular performance measure, delaying the starting time of the job can produce a better solution. Hence, not only do we determine the job sequencing and the job assignment, but also we determine the starting time of the job. We propose a triple‐chromosome genetic algorithm that represents the job sequencing, the job assignment and the optimal starting time of the job simultaneously. A self‐adaptive algorithm is developed to determine the value of the third chromosome after crossover and mutation process. Numerical experiment and statistical analysis are conducted to show the appropriateness and efficacy of the proposed approach. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Benchmark your students’ persistence, retention against national statistics
Authors: Hope Joan
Published: November 2019

More than a quarter of entering students leave college within their first year. That's according to the National Student Clearinghouse Research Center's Persistence and Retention Snapshot Report released last summer. Among the 3.5 million students who enrolled in college for the first time in fall 2017, 74% (2.6 million) were still enrolled at any higher education institution in fall 2018. The first‐year persistence rate rose 2.2% over eight years, the data showed.
A Metric Space with LCOE Isolines for Research Guidance in wind and hydrokinetic energy systems
Authors: Garcia‐Sanz Mario
Published: November 2019

This paper introduces a new Metric Space to guide the design of advanced wind energy systems and hydrokinetic energy converters such as tidal, ocean current and riverine turbines. The Metric Space can analyse farms that combine different or identical turbines and stand‐alone turbines. The first metric (M1) of the space considers the efficiency of the turbines in the farm, which is also proportional to the specific power per swept area at a given wind/water velocity (W/m2). The second metric (M2) describes the specific rotor area per unit of mass of the turbines (m2/kg). Both metrics depend on the primary design characteristics of the turbines, such as swept area, system size and mass, materials and efficiency, and are independent at first from external characteristics, such as atmospheric and ocean site conditions, cost of materials and economic factors. Combining both metrics, and for a given set of external characteristics, the resulting Metric Space M2/M1 displays the Levelized Cost of Energy (LCOE) standards as isolines. This graphical representation provides a quick understanding of the cost and state of the technology. It also offers a practical guidance to choose the research tasks and strategy to design advanced wind and hydrokinetic energy systems. The paper applies the new Metric Space to several case studies, including large and small onshore wind turbines, floating and bottom‐fixed offshore wind turbines, downwind rotors, multi‐rotor and hybrid systems, airborne wind energy systems, wind farms and tidal energy converters.
A Conversation Among Student Affairs Leadership Educators
Authors: Rocco Melissa L. , Pelletier Jennifer
Published: November 2019

This chapter explores the nature of leadership education work and the development of leadership educator identity in a student affairs context through the lenses of seven colleagues in conversation with one another.
Primate Infectious Disease Ecology: Insights and Future Directions at the Human-Macaque Interface
Authors: Balasubramaniam Krishna N. , Sueur Cédric , Huffman Michael A. , MacIntosh Andrew J. J.
Published: November 2019

Global population expansion has increased interactions and conflicts between humans and nonhuman primates over shared ecological space and resources. Such ecological overlap, along with our shared evolutionary histories, makes human-nonhuman primate interfaces hot spots for the acquisition and transmission of parasites. In this chapter, we bring to light the importance of human-macaque interfaces in particular as hot spots for infectious disease ecological and epidemiological assessments. We first outline the significance and broader objectives behind research related to the subfield of primate infectious disease ecology and epidemiology. We then reveal how members of the genusMacaca, being among the most socioecologically flexible and invasive of all primate taxa, live under varying degrees of overlap with humans in anthropogenic landscapes. Thus, human-macaque interfaces may favor the bidirectional exchange of parasites. We then review studies that have isolated various types of parasites at human-macaque interfaces, using information from the Global Mammal Parasite Database (GMPD:http://www.mammalparasites.org/). Finally, we elaborate on avenues through which the implementation of both novel conceptual frameworks (e.g., Coupled Systems, One Health) and quantitative network-based approaches (e.g., social and bipartite networks, agent-based modeling) may potentially address some of the critical gaps in our current knowledge of infectious disease ecology at human-primate interfaces.
Tibetan Macaque Social Style: Covariant and Quasi-independent Evolution
Authors: Balasubramaniam Krishna N. , Ogawa Hideshi , Li Jin-Hua , Ionica Consuel , Berman Carol M.
Published: November 2019

Understanding the evolutionary origins of group social structure is vital to understanding how individuals deal with the trade-offs of group living. In this chapter, we review our previous work related to social style in Tibetan macaques and across macaque species, focusing on whether, and the extent to which, indicators of social style covary with one another and with phylogenetic closeness as previously hypothesized and/or evolved as quasi-independent traits. Covariation is consistent with a phylogenetic model in which social style traits are structurally linked and coevolve over time, whereas the quasi-independence argument is more consistent with some degree of independent evolution of traits in response to current ecological conditions. We describe how a mixture of both despotic and tolerant social style traits in Tibetan macaques provides evidence for quasi-independent adaptive evolution. Nevertheless, evidence for covariation is discernible across higher organizational scales such as between some species and lineages of macaques. Findings from these studies suggest that aspects of macaque social style appear to be shaped both by underlying influences of ancestry on linked traits and by quasi-independent, adaptive responses by animals to variation in current conditions. This view appears to be consistent with the concept of social structure as the product of social reaction norms. We end by discussing avenues of future research on Tibetan macaque social structure, including male social style traits and the roles of paternal relatedness, infectious disease risk, intraspecific variation, and the phylogeography of ancestral species.
Digital Heritage
Authors: Wang Xinyuan , Lasaponara Rosa , Luo Lei , Chen Fulong , Wan Hong , Yang Ruixia , Zhen Jing
Published: November 2019

Natural and cultural heritage, the common wealth of human beings, are keys to human understanding of the evolution of our planet and social development. The protection and conservation of natural and cultural heritage is the common responsibility of all mankind. Spatial information technology provides a new applied theory and tool for the protection and utilization of natural and cultural heritage. This chapter is divided into four parts. The first part elaborates the connotation of digital heritage, the differences and connections between digital heritage and physical heritage, the technology of digital heritage formation and the research objectives and content of digital heritage. Parts 2 and 3 discuss the contents and methods of digital natural heritage and cultural heritage, respectively, and some practical case studies. In the fourth part, the future development trends of digital heritage research in protection and utilization are described, as well as six research directions that deserve attention.
Soft bootstrap and effective field theories
Authors: Low Ian , Yin Zhewei
Published: November 2019

Abstract

The soft bootstrap program aims to construct consistent effective field theories (EFT’s) by recursively imposing the desired soft limit on tree-level scattering amplitudes through on-shell recursion relations. A prime example is the leading two-derivative opera­ tor in the EFT of SU(N) x SU(N)/SU(N) nonlinear sigma model (NLSM), where 𝒪(p2 ) amplitudes with an arbitrary multiplicity of external particles can be soft-bootstrapped. We extend the program to 𝒪(p4) operators and introduce the “soft blocks,” which are the seeds for soft bootstrap. The number of soft blocks coincides with the number of independent operators at a given order in the derivative expansion and the incalculable Wilson coefficient emerges naturally. We also uncover a new soft-constructible EFT involving the “multi-trace” operator at the leading two-derivative order, which is matched to SO(N + 1) /SO(N) NLSM. In addition, we consider Wess-Zumino-Witten (WZW) terms, the existence of which, or the lack thereof, depends on the number of flavors in the EFT, after a novel application of Bose symmetry. Remarkably, we find agreements with group­ theoretic considerations on the existence of WZW terms in SU(N) NLSM for N ≥ 3 and the absence of WZW terms in SO(N) NLSM for N ≠ 5.
3-D DC Resistivity Forward Modeling Using the Multi-resolution Grid
Authors: Gao Jingyu , Smirnov Maxim , Smirnova Maria , Egbert Gary
Published: November 2019

We implemented a novel multi-resolution grid approach to direct current resistivity (DCR) modeling in 3-D. The multi-resolution grid was initially developed to solve the electromagnetic forward problem and helped to improve the modeling efficiency. In the DCR forward problem, the distribution of the electric potentials in the subsurface is estimated. We consider finite-difference staggered grid discretization, which requires fine grid resolution to accurately model electric potentials around the current electrodes and complex model geometries near the surface. Since the potential variations attenuate with depth, the grid resolution can be decreased correspondingly. The conventional staggered grid fixes the horizontal grid resolution that extends to all layers. This leads to over-discretization and therefore unnecessary high computational costs (time and memory). The non-conformal multi-resolution grid allows the refinement or roughening for the grid’s horizontal resolution with depth, resulting in a substantial reduction of the degrees of freedom, and subsequently, computational requirements. In our implementation, the coefficient matrix maintains its symmetry, which is beneficial for using the iterative solvers and solving the adjoint problem in inversion. Through comparison with the staggered grid, we have found that the multi-resolution grid can significantly improve the modeling efficiency without compromising the accuracy. Therefore, the multi-resolution grid allows modeling with finer horizontal resolutions at lower computational costs, which is essential for accurate representation of the complex structures. Consequently, the inversion based on our modeling approach will be more efficient and accurate.