3,020 research outputs found

    Impact of surface roughness in nanogap plasmonic systems

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    Recent results have shown unprecedented control over separation distances between two metallic elements hundreds of nanometers in size, underlying the effects of free-electron nonlocal response also at mid-infrared wavelengths. Most of metallic systems however, still suffer from some degree of inhomogeneity due to fabrication-induced surface roughness. Nanoscale roughness in such systems might hinder the understanding of the role of microscopic interactions. Here we investigate the effect of surface roughness in coaxial nanoapertures resonating at mid-infrared frequencies. We show that although random roughness shifts the resonances in an unpredictable way, the impact of nonlocal effects can still be clearly observed. Roughness-induced perturbation on the peak resonance of the system shows a strong correlation with the effective gap size of the individual samples. Fluctuations due to fabrication imperfections then can be suppressed by performing measurements on structure ensembles in which averaging over a large number of samples provides a precise measure of the ideal system's optical properties

    EFFECTIVENESS OF BLOCK ITERATIVE SCHEMES IN COMPUTING THE SEISMIC RESPONSE OF BUILDINGS WITH NONLINEAR BASE ISOLATION

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    The conventional form of solving the equations of motion governing the seismic response of building structures with nonlinear base isolation consists of using monolithic step by step integrationmethods. As an alternative, the application of a block iterative scheme is examined in this paper. After describing the particularities of the equations of motion of the structure with base isolation, different block iterative schemes are described. Their effectiveness is discussed and compared with that of monolithic step by step integration methods. Adequate examples are used with the aim of performing numerical comparisons

    FIC/FEM formulation with matrix stabilizing terms for incompressible flows at low and high Reynolds numbers

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s00466-006-0060-yWe present a general formulation for incompressible fluid flow analysis using the finite element method. The necessary stabilization for dealing with convective effects and the incompressibility condition are introduced via the Finite Calculus method using a matrix form of the stabilization parameters. This allows to model a wide range of fluid flow problems for low and high Reynolds numbers flows without introducing a turbulence model. Examples of application to the analysis of incompressible flows with moderate and large Reynolds numbers are presented.Peer ReviewedPostprint (author's final draft

    Numerical modelling of compressible laminar and turbulent flow. The Cbs algorithm

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    This work is about the development of a general algorithm for the numerical solution of flow equations: the Navier-Stokes set. This set of differential equations models the time dependent behavior of fluids. It is formed by continuity, linear momentum and an energy transport equations. The algorithm here described is a general one since it can handle equally a great variety of problems, ranging from incompressible to compressible flows, viscous to inviscid, stationary and transient, all of them phisically modeled by the same set of differential equations. In the present work, a quest for a general algorithm is described, following one of many possible ways to tackle the problem. In general, this is done extending methods either from compressible to incompressible flows or from incompressible to compressible ones

    Quick Read and Easy Read Summary - End of Three Year Evaluation of the Access and Inclusion Model

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    This is a quick-read/easy read summary of the evaluation for people who have additional needs, such as a learning disability, or who want to read a quick summary of the findings. About the research that this summary is based on: The Department for Children, Equality, Disability, Integration, and Youth (DCEDIY) commissioned this evaluation. Its purpose was to investigate the implementation and impact of the Access and Inclusion Model (AIM), from the perspective of multiple stakeholders. The findings of the evaluation would inform the continuous improvement of AIM within the contemporaneous policy context. The evaluation was led by the University of Derby (UoD) consortium and took place between December 2020 and December 2021. Substantive evidence about the implementation and impact of AIM was gathered in this evaluation. Evidence is drawn from the participation of over 2,000 stakeholders and the analysis of over 140 documents. The sample for the study has comprised: •50 sources of documentary evidence (policy documents, agency reports, statistics, websites) •94 sources from the research and academic literature •1,157 parent/carers in an online survey •732 providers in an online survey •79 stakeholders (AIM delivery partners and agencies, disability sector, parent/carers, and ELC practitioners) •14 children who are supported by AIM •14 pre-school settings that are engaged with AI

    Nitsche's prescription of Dirichlet conditions in the finite element approximation of Maxwell's problem

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    In this paper we consider the finite element approximation of Maxwell's problem and analyse the prescription of essential boundary conditions in a weak sense using Nitsche's method. To avoid indefiniteness of the problem, the original equations are augmented with the gradient of a scalar field that allows one to impose the zero divergence of the magnetic induction, even if the exact solution for this scalar field is zero. Two finite element approximations are considered, namely, one in which the approximation spaces are assumed to satisfy the appropriate inf-sup condition that render the standard Galerkin method stable, and another augmented and stabilised one that permits the use of finite element interpolations of arbitrary order. Stability and convergence results are provided for the two finite element formulations considered

    Social segregation of indigenous migrants in Mexico: An overview from Monterrey

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    In Mexico, rural to urban migration is a clearly noticeable phenomenon. During the last few years, there has been spontaneous growth in the migration of indigenous people towards the northern cities of Mexico, especially to Monterrey, in search of employment. Once the migrants arrive in this metropolis, they face difficulties adjusting and adapting to the city environment because of hidden discrimination. The main argument and hypothesis of this paper is that indigenous people isolate themselves and segregate themselves socially due to fear of (cultural and racial) discrimination and violence. For this study, data were obtained from fieldwork carried out during 2009 and 2010 in Monterrey, Mexico, where we interviewed 350 indigenous people that had moved there from different parts of the country

    Implementing counter hegemonic research approaches to evaluating high-profile, national policies in Early Childhood Education and Care

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    This paper reports on the counter hegemonic research methods which were applied to an evaluation of a national policy (henceforth referred to as ‘the policy’) for the inclusion of children with disabilities in early childhood education and care (ECEC). Its focus is on methodological design. It is relevant to policy-makers, researchers and practitioners who wish to enact research methods that affirm the expert status of both children and practitioners as ‘truth’ knowers in an inclusive milieu

    Sustainable landscape in arid zones : useful ornamental xeric species

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    Se analiza el valor económico, ecológico y paisajístico de especies vegetales, pertenecientes a la flora espontánea de Mendoza (Argentina), resistentes a la sequía y que pueden alcanzar porte arbóreo. Su empleo ahorra agua de riego en espacios verdes ornamentales y de protección ambiental. Se sugiere medidas de conservación de las especies espontáneas más útiles paisajísticamente, así como normas generales sobre métodos de plantación y mantenimiento. Se recomiendan especies leñosas espontáneas de la provincia, de bajo requerimiento hídrico, utilizables paisajísticamente.This paper analyzes the economic, ecological and landscape value of drought resistant species from the spontaneous flora of Mendoza (Argentina). Some of such species could reach tree size and its use might save the irrigation water used for ornamental and environmental protection areas. Actions to protect the most useful spontaneous species, as well as general rules for plantation and maintenance are suggested. Spontaneous wooden species of low water requirements, to use in different landscape objectives, are recommended.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Manzano, Enrique R.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Carrieri, Sergio A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Fioretti, Sonia B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuari
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