bluuebunny/crossref_metadata_2025_split huggingface dataset:
Public firms' merger, employment, and welfare in developing countries: A general equilibrium analysis
Authors: Chao Chi‐Chur , Ee Mong Shan , Wang Leonard F. S. 
Published: December 2017

AbstractThis paper examines the effect of a merger of state‐owned firms on wage gap, employment, and social welfare in a general equilibrium setting. For a developing economy with state‐owned firms in the urban sector, a merger via a reduction in the number of the urban state‐owned firms can reduce the cost of capital. It then lowers the skilled wage rate through the factor‐substitution effect, while it raises the unskilled wage by the inflow of capital to the rural sector and hence lowers urban unemployment. In addition, the reduction in the number of the urban state‐owned firms can yield a scale effect to the firms. The beneficial effects on higher urban output and less urban unemployment can improve social welfare of the developing economy.
IDENTIFICANDO A EVOLUÇÃO CONCEITUAL NO ENSINO DE ELETROMAGNETISMO, ATRAVÉS DE UMA UEPS BASEADA NUM SISTEMA DE SOM AUTOMOTIVO GERADOR DE ENERGIA
Authors: Spohr Carla Beatriz , Garcia Isabel Krey , Pereira Santarosa Maria Cecília 
Published: December 2017

No presente estudo apresenta-se a proposta de uma Unidade de Ensino Potencialmente Significativa (UEPS) para o ensino de eletromagnetismo a partir de um circuito elétrico capaz de transformar a energia sonora emitida pelo alto-falante em energia elétrica para recarregar a bateria. Tal circuito foi considerado significativo para apresentar as relações entre os conceitos trabalhados, por exemplo, corrente elétrica e indução eletromagnética com o funcionamento de alto-falantes e microfones. Para tanto, acadêmicos do Curso de Licenciatura em Ciências da Natureza (UNIPAMPA – Uruguaiana/RS) se propuseram a elaborar, implementar e avaliar uma UEPS para ensinar conceitos de eletromagnetismo para alunos de nível médio, a partir da utilização do circuito elétrico que mostrou ser um instrumento provocador da motivação do aprendiz, uma das condições necessárias e imprescindíveis para que ocorra a aprendizagem significativa. Ao final da UEPS, foi notória a motivação por parte dos acadêmicos responsáveis por ensinar com fundamentos teóricos baseados na teoria construtivista ausubeliana, bem como por parte dos estudantes de ensino médio através da predisposição em aprender, evidenciada ao longo dos encontros. Os resultados obtidos no presente estudo comparam os avanços, retrocessos e estagnações dos alunos participantes, em relação às evidências de aprendizagem significativa indicadas através das respostas dadas pelos alunos ao início e ao final dos encontros. Os dados apontam que a evolução conceitual se deve ao planejamento e aplicação da UEPS, que procurou observar constantemente a organização sequencial dos conteúdos a serem desenvolvidos, de maneira coerente com as relações de dependência que existem naturalmente entre eles. Além da organização dos conteúdos previstos no planejamento da UEPS, considerou-se a cada encontro o conhecimento prévio do aluno, bem como a presença de subsunçores em sua estrutura cognitiva para possibilitar a ancoragem de novos conhecimentos. Reitera-se que os frutos desta pesquisa, estão em conformidade com os princípios da teoria psicológica de Ausubel, de que para facilitar a aprendizagem significativa deve-se levar em consideração: o conhecimento prévio do aluno, sua predisposição para aprender e o material apresentado deve ser potencialmente significativo.
Træstruktur i en skov af fortolkninger
Authors: Christensen Ken Ramshøj 
Published: December 2017

Denne artikel fremfører først et logisk argument for at det ikke er muligt at redegøre for sprogtilegnelsen og sprogbrugen ved hjælp at funktion og hyppighed alene. Der er også behov for at tage form-delen – dvs. syntaksen – alvorligt, for den er forudsætningen for funktionen. Dernæst gennemgår artiklen resultaterne fra en række danske neuro- og psykolingvistiske undersøgelser der understøtter den formelle lingvistiks grundtese, nemlig at det er muligt at adskille sproglig form og sproglig funktion. Forsøgene viser at vi laver usandsynlige fortolkninger undervejs i sprogforståelsen, og at sandsynlighed og hyppighed ikke forklarer hvorfor eller hvordan vi misforstår visse sætningstyper, eller hvorfor vi tilskriver mening til sætninger der ikke har en fast betydning. Selvom visse semantiske og syntaktiske kriterier normalt skal være opfyldt, er det muligt så at sige at kortslutte det sproglige fortolkningssystem og dermed adskille form og funktion. Der argumenteres for at hjernen er en forudsigelsesmaskine der konstant konstruerer og opdaterer mentale modeller af verden omkring os, og én af disse modeller er sprogets grammatik. Ligesom enhver anden form for søge- eller læringsalgoritme må sprogforståelsen nødvendigvis være styret af visse formelle principper.
In Situ Tropical Peatland Fire Emission Factors and Their Variability, as Determined by Field Measurements in Peninsula Malaysia
Authors: Smith T. E. L. , Evers S. , Yule C. M. , Gan J. Y. 
Published: December 2017

AbstractFires in tropical peatlands account for >25% of estimated total greenhouse gas emissions from deforestation and degradation. Despite significant global and regional impacts, our understanding of specific gaseous fire emission factors (EFs) from tropical peat burning is limited to a handful of studies. Furthermore, there is substantial variability in EFs between sampled fires and/or studies. For example, methane EFs vary by 91% between studies. Here we present new fire EFs for the tropical peatland ecosystem; the first EFs measured for Malaysian peatlands, and only the second comprehensive study of EFs in this crucial environment. During August 2015 (under El Niño conditions) and July 2016, we embarked on field campaigns to measure gaseous emissions at multiple peatland fires burning on deforested land in Southeast Pahang (2015) and oil palm plantations in North Selangor (2016), Peninsula Malaysia. Gaseous emissions were measured using open‐path Fourier transform infrared spectroscopy. The IR spectra were used to retrieve mole fractions of 12 different gases present within the smoke (including carbon dioxide and methane), and these measurements used to calculate EFs. Peat samples were taken at each burn site for physicochemical analysis and to explore possible relationships between specific physicochemical properties and fire EFs. Here we present the first evidence to indicate that substrate bulk density affects methane fire EFs reported here. This novel explanation of interplume, within‐biome variability, should be considered by those undertaking greenhouse gas accounting and haze forecasting in this region and is of importance to peatland management, particularly with respect to artificial compaction.
Experimental Constraints on Ferropericlase (Mg, Fe)O Melt Viscosity Up to 70 GPa
Authors: Du Zhixue , Deng Jie , Lee Kanani K. M. 
Published: December 2017

AbstractDuring Earth's accretion, Earth's mantle is expected to have been a magma ocean due to large impacts. As such, properties of molten mantle materials are key to understanding Earth's thermochemical evolution. However, due to experimental challenges, transport properties at lower mantle pressures, particularly viscosity, are poorly constrained for mantle melts. In this study, we use quenched dendritic textures to estimate melt viscosities at high pressures for (Mg, Fe)O ferropericlase, one of the major components of the mantle. We find that the viscosity of (Mg, Fe)O melt near liquidus temperatures is ~10−3–10−2 Pa s over the pressure range of 3–70 GPa, which is ~1–2 orders of magnitude lower than previous results for Si‐rich melts at similar conditions. This may have implications for magma ocean cooling and thermochemical evolution of the mantle.
Experimental Study of Stick‐Slip Failure Processes and Effect of Physical Properties on Stick‐Slip Behavior
Authors: Zhou Xiaoping , Ma Wen , Yang Luhao , Bi Jing , Cheng Hao 
Published: December 2017

AbstractTo investigate the process of stick‐slip shear failure, small‐scale poly methyl methacrylate samples with friction faults and a high‐speed recording experiment system are used. The evolution of shear stress and slip displacement clearly shows both the propagation of stick‐slip failures and the local slip‐weakening behavior of the fault. The distribution of local stress ratioτyx/σyalong the fault is of great significance to determining the nucleation location. The interrelations among local shear stresses, slip displacements, slip velocities, and slip accelerations show the details of local deformations and motions of breakdown near the crack tip. Four distinctive phases of local breakdown process are found in both the nucleation zone and the dynamic rupture propagation zone. Experiments with three prefabricated roughnesses of the fault surfaces are conducted at normal stresses varying from 2 MPa to 4 MPa. The critical crack length decreases and the rupture velocity increases with increasing normal stress or decreasing the roughness. Both the local dynamic stress drop Δτdand local breakdown stress drop Δτbgenerally increase with increasing normal stresses and decrease with increasing the roughness. Although the critical slip‐weakening displacementucseems to be insensitive to normal stress, it decreases as the fault becomes smoother. The shear fracture energyGc, which is determined by Δτbanduc, increases with an increase in the normal stress and increases with increasing the roughness. In addition, the linear relations of Δτd, Δτb, anducto the static friction coefficient μsare found, and a quadratic function relatingGcand μsis established.
Stochastic Finite Element Methods
Authors: Gutiérrez Miguel A. , Krenk Steen 
Published: December 2017

Abstract
This chapter gives an overview of finite element related methods for the solution of problems in which the system has random properties. The notion of stochastic variables and fields is introduced and details are given for the normal and log‐normal distributions. Discretization methods for random fields and efficient algorithms for evaluation of the sensitivity to the random input are presented. The two dominating approximate methods for obtaining the statistical properties of the response from those of the stochastic properties of the system – the perturbation and the spectral method – are described in detail, and it is explained how statically determinate systems constitute a special case, permitting more general results. The final section deals with reliability methods, the purpose of which is to obtain the probability or a probability estimate, of a rare event, for example, failure. The methods are introduced by means of simple examples, with a view to making the text a self‐contained introduction and survey.
Acoustics
Authors: Thompson Lonny L. , Pinsky Peter M. 
Published: December 2017

AbstractState‐of‐the‐art computational methods for linear acoustics are reviewed. The equations of linear acoustics are summarized and then transformed to the frequency domain for time‐harmonic waves governed by the Helmholtz equation. Three major current challenges in the field are specifically addressed: numerical dispersion errors that arise in the approximation of short unresolved waves, polluting resolved scales and requiring a large computational effort; the effective treatment of unbounded domains by domain‐based methods; and parallel iterative methods for large complex, ill‐conditioned and possibly indefinite equation systems for high‐frequency problems.A priorierror estimates, including both dispersion (phase error) and global pollution effects for moderate to large wave numbers are discussed. Stabilized and other wave‐based discretization methods are reviewed. Domain‐based methods for modeling exterior domains are described including Dirichlet‐to‐Neumann (DtN) methods, absorbing boundary conditions, infinite elements, and the perfectly matched layer (PML). Efficient equation‐solving methods for the resulting complex‐symmetric (non‐Hermitian) matrix systems are discussed including parallel iterative methods and domain decomposition methods. Numerical methods for direct solution of the acoustic wave equation in the time domain are also reviewed.
Boundary Integral Equation Methods for Elastic and Plastic Problems
Authors: Bonnet Marc 
Published: December 2017

AbstractThis chapter deals with formulations based on boundary integral equations (BIEs) for elastic and plastic problems. After a brief review of the basic integral identities of solid mechanics and issues associated with the singular character of the fundamental solutions, the collocation and symmetric Galerkin BIE formulations and the associated boundary element methods (BEMs) are presented in their conventional form where the complete matrix equation is set up using numerical integration and stored. This approach being inadequate for large problem sizes, fast solution techniques are then reviewed, with emphasis on the fast multipole method. Next, BEMs in both collocation and symmetric Galerkin form are described for fracture mechanics and small‐strain elastoplasticity. The treatment of the hypersingular integrals arising in the integral representation of tractions on the crack surface or of strains at potentially plastic interior points is discussed, along with other issues. Shape sensitivity analysis techniques are also presented, based on either the direct differentiation of the primary elastic BIE or an adjoint solution. Finally, the symmetric Galerkin BIE is used to define a symmetric formulation for BEM–FEM coupling.
Boundary Element Methods for the Dynamic Analysis of Elastic, Viscoelastic, and Piezoelectric Solids
Authors: Gaul Lothar , Kögl Martin , Moser Friedrich , Schanz Martin 
Published: December 2017

AbstractElastic solids are the simplest model for deformable solid continua, when any deformation vanishes after unloading. The extension to viscoelastic solids takes creep and relaxation effects into account. If additionally to the elastic fields also electric fields influence the behavior of the solid a piezoelectric theory has to be used. The dynamic response of these three models of solids is governed by partial differential equation. The Boundary Element Method utilises the corresponding integral representation of these partial differential equations. The numerical realisation based on a discretization in space and time is the Boundary Element Method.
Aerodynamics
Authors: Witherden Freddie D. , Jameson Antony 
Published: December 2017

AbstractComputational methods are now pervasive in the science of aerodynamics. Because previously existing numerical methods proved inadequate for fluid flow simulations, the emergence of computational fluid dynamics (CFD) as a distinct discipline has sparked the development of an entirely new class of algorithms, and a supporting body of theory, which are the main theme of this chapter. After a review of mathematical models of fluid flow, methods for solving the transonic potential flow equation (of mixed type) are examined. The central part of the chapter discusses the formulation and implementation of shock‐capturing schemes for the Euler and Navier–Stokes equations. The chapter next discusses the merits of the contrasting approaches of finite difference, finite volume, and finite element methods for the treatment of flows in complex geometric domains, together with the treatment of boundary conditions. A detailed presentation of explicit and implicit time‐stepping schemes for both steady and unsteady flows precedes a discussion of preconditioning and multigrid procedures for accelerating the convergence of steady‐state calculations. High‐order methods suitable for conducting unsteady simulations on unstructured grids are also presented. In order to realize the potential benefits of CFD, it is essential to move beyond simulation to aerodynamic (and ultimately multidisciplinary) optimization. The chapter concludes with a discussion of aerodynamic shape optimization via control theory.
CFD‐Based Nonlinear Computational Aeroelasticity
Authors: Farhat Charbel 
Published: December 2017

AbstractThis chapter overviews a three‐field formulation of nonlinear aeroelastic problems, where the fluid is modeled by the arbitrary Lagrangian–Eulerian (ALE) form of either the Euler or Navier–Stokes equations; the structure is represented by a detailed finite element model, and the fluid‐mesh is unstructured, dynamic, and constructed by a robust structure‐analogy–based method. It also discusses recent advances in the computational algorithms associated with this approach for modeling nonlinear fluid/structure interaction problems. These include CFD schemes that are formally second‐order time‐accurate on moving grids, energy‐transfer–conserving methods for discretizing transmission conditions across nonmatching fluid and structure discrete interfaces, and state‐of‐the‐art loosely coupled algorithms for solving efficiently coupled systems of fluid and structural equations arising from the discretization of real aircraft configurations. A taste of the capabilities of such algorithms is provided by reporting on their validation for an F‐16 fighter aircraft configuration in various subsonic, transonic, and supersonic airstreams, and at various load factors. The chapter concludes with a discussion of the feasibility and merit of the overviewed computational technology for accurately extracting the flutter envelopes of civilian and military aircraft, and a perspective on future research in CFD‐based nonlinear computational aeroelasticity.
The Use of Mixed Finite Element Methods for Viscoelastic Fluid Flow Analysis
Authors: Baaijens Frank P. T. , Hulsen Martien A. , Anderson Patrick D. 
Published: December 2017

AbstractThe numerical analysis of non‐Newtonian viscoelastic flows is a challenging task, and requires accurate, efficient, and robust computational methods. In this work, mixed finite element methods are used for that purpose. They are introduced within the context of closed‐form differential constitutive models. Their application to steady and time‐dependent viscoelastic flows and stability analysis is discussed. Application to model polymer melt flows is briefly addressed. These techniques can also be adapted to solve problems with models that cannot be written as closed‐form differential models. Two examples thereof are the deformation fields method for closed‐form constitutive equations and the Brownian configuration fields formulation for stochastic constitutive models.
Combustion
Authors: Poinsot Thierry J. , Veynante Denis P. 
Published: December 2017

AbstractThis chapter describes the basic phenomena controlling reacting flows and the corresponding computational methodologies. Combustion regimes (premixed or diffusion flames, laminar or turbulent cases, stable or unstable behavior) are first defined before introducing the basic terminology required to understand numerical techniques for reacting flows. The governing equations for combustion are more complex than those used in classical aerodynamics, and their specificities are discussed before describing numerical methods for laminar flames. Finally, the various methods used for turbulent flames are discussed, focusing on recent techniques such as direct numerical simulations and large eddy simulations.
Reproducing Kernel Particle Method for Solving Partial Differential Equations
Authors: Chen Jiun‐Shyan , Liu Wing Kam , Hillman Michael C. , Chi Sheng‐Wei , Lian Yanping , Bessa Miguel A. 
Published: December 2017

AbstractThis chapter gives a state of the art review of the weak‐form‐ and strong‐form‐based reproducing kernel particle method (RKPM). The construction of the continuous and discrete reproducing kernel (RK) approximations and their approximation properties are first presented. Recent developments and their connection to other meshfree methods, as well as an overview of the inherent multiresolution capabilities of the RKPM, are then given. The Galerkin‐based method is discussed in detail, along with several recent advances in quadrature and stability. A review of strong form collocation with RK approximation as well as implicit gradient enhancement is presented. Formulations for large deformation and contact problems for which the RKPM is particularly well suited are also discussed.
Topology Optimization
Authors: Maute Kurt 
Published: December 2017

Abstract
Topology optimization is a computational approach to systematically optimize the conceptual layout and the geometry of a body on the basis of a basic description of a design problem. In contrast to other design optimization methods, the outer shape of the body and the geometry of the material interfaces within the body may undergo radical changes in the optimization process, including both shape and topological changes. This unique feature reduces significantly the dependence of the optimized design on the initial guess from which the optimization process is started and allows finding nonintuitive solutions for complex design problems. Formulating optimization problems that yield meaningful, practical designs requires a solid understanding of the physical phenomena that dominate the body's functionality, as well as insight into the mathematical characteristics of the high‐dimensional design spaces used in topology optimization. Topology optimization methods involve a broad variety of computational techniques for describing the geometry of the body, predicting the physical phenomena of interest, and searching for the optimum design. This chapter provides an introduction to modern topology optimization. Instead of providing a comprehensive overview, the most important and widely used approaches are discussed in sufficient detail to provide the reader with a basic understanding of the state of the art of topology optimization.
Shape Optimization
Authors: Bletzinger Kai‐Uwe 
Published: December 2017

AbstractThis chapter gives basic information about those aspects which make structural shape optimization different from other problem types of optimization. It concentrates on those topics which deal with the control of shape (continuous and parametric), the regularization of problem formulation, the treatment of the infinity of design space and some further aspects which are specific to numerical and parametric shape optimization. As a consequence, there is little presented about general optimization theory or algorithms, or specific aspects of implementation and applications are restricted to typical, illustrative examples. In particular, a unified approach is displayed which allows to see the floating transition between free shape optimization and computer aided design‐based parametric shape optimization on a sound theoretical basis.
High‐Order Methods for CFD
Authors: Abgrall R. , Ricchiuto Mario 
Published: December 2017

AbstractWe provide a review of high‐order methods for computational fluid dynamics (CFD). Besides recalling some classical methods, we show a framework that, on one hand, allows us to see and work with these methods under a different light, and, on the other, provides a different path to construct numerical methods for flow equations. In particular, we focus on residual‐based techniques and residual distribution methods as a framework to construct schemes of arbitrary order.