Метафоричність та інші стилістичні засоби персуазивності у текстах на екотематику (на матеріалі книги "Тиха весна" Р. Карсон)

Стаття присвячена виявленню і аналізу метафор та інших лінгвістичних засобів персуазивності в книзі Р. Карсон "Тиха весна", всесвітньо визнаного маніфесту екологічного руху. Були досліджені особливості організації дискурсивного простору тексту та засоби класичної аргументації, виявлені біблійні, літературні та культурні алюзії, розглянуті стилістичні фігури, що сприяють підвищенню рівня аргументативності тексту.Статья посвящена анализу метафор и других лингвистических средств персуазивности в книге Р. Карсон "Тихая весна", всемирно известного манифеста экологического движения. Были исследованы особенности организации дискурсивного пространства текста и средства классической аргументации, обнаружены библейские, литературные и культурные аллюзии, рассмотрены стилистические фигуры, способствующие повышению уровня аргументативности текста.The article deals with the analysis of metaphors and other linguistic means of persuasiveness in the book "Silent Spring" by R. Carson, known as the ecological movement manifest. The specific organization of the text's discursive space and the means of classical argumentation were investigated. The biblical, literary and cultural allusions were found. The stylistic figures aimed at the text's argumentativity were analyzed

Формирование композиционных покрытий никель – бор – азот

The methods of X-ray analysis and electron microscopy have been used to study the structure of nitrogen-ion implanted electrochemical Ni–B coatings with the boron concentration of 8,14 and 20 at %. The implantation is shown to increase coating microhardness from 5,1-5,9 GPa to 10,8-11,7 GPa. The hardness increase of coatings is attributed to decrease of nickel boride particle size and formation of γ-BN

Coarse level Newton-Krylov acceleration of sub-iterations in partitioned fluid-structure interaction

Computational fluid-structure interaction is commonly performed using a partitioned approach. For strongly coupled problems sub-iterations are required, increasing computational time as flow and structure have to be resolved multiple times every time step. Reductions in computing times can be achieved by e.g. improving the convergence of the sub-iteration technique and/or performing sub-iterations on a coarse level, but also by improving the iterative solver used in the flow solver. In this paper we investigate the combination of a multilevel acceleration technique for sub-iterations which employs a Newton-Krylov solver on the coarse level to obtain high convergence for the correction term and a multigrid solver which performs only a limited amount of iterations on the fine level to reduce memory and computing requirements. For switching between a coarse grid correction and fine grid solve, an automated coarse grid ACG(r) selection algorithm is proposed. The algorithm is applied to an academic, two dimensional test case with incompressible flow. Compared to sub-iterating with a (memory intensive) JFNK algorithm on the fine mesh, the hybrid algorithm already requires 10% less computing time. When compared to sub-iterating with multigrid, the performance increase for the hybrid scheme is a factor 3

Experimental benchmark and numerical validation of a free heaving airfoil

In order to validate fluid-structure interaction solvers, a one degree of freedom (1 DOF) aeroelastic experiment is performed. A rigid wing with an harmonically actuated flap, is suspended by springs to allow a free heaving motion. Displacements and time dependent aerodynamic forces are measured for reduced flap frequencies ranging from k = 0.1 to k = 0.3. Simulations with three codes of different complexity level are performed for validation purposes: theodorsens model, a 2D panel code and 2D URANS, all coupled to a 1 DOF structural model. Results presented by bode diagrams, show differences in both the displacement and the lift between numerical work and experiment. Although there is an offset, consistency is found between displacements, forces and phase angles in the system for all simulations and the experiment

Higher order time integration schemes for thermal coupling of flows and structures

The application of higher order implicit time integration schemes to conjugate heat transfer problems is analyzed with Dirichlet-Neumann as the decomposition method. In the literature, only up to second order implicit time integration schemes have been reported while there is a potential for gaining computational efficiency using higher orders. For loose coupling of the domains, the IMEX scheme consisting of the ESDIRK scheme for integrating the governing equations within the subdomains and an ERK scheme for explicit integration of the explicit coupling terms is utilized. The IMEX scheme is analyzed for two cases. In one, the material properties of the coupled domains are the same and in the other they are different. While for both cases, the IMEX scheme preserves the design order of the time integration scheme, different stability and accuracy properties are observed for the two. Finally, the computational efficiency of the higher order IMEX schemes relative to the second order scheme is demonstrated using a test case in 2-D involving coupled conduction problem of three domains

Rosenbrock time integration for unsteady flow simulations

This contribution compares the efficiency of Rosenbrock time integration schemes with ESDIRK schemes, applicable to unsteady flow and fluid-structure interaction simulations. Compared to non-linear ESDIRK schemes, the linear implicit Rosenbrock- Wanner schemes require subsequent solution of the same linear systems with different right hand sides. By solving the linear systems with the iterative solver GMRES, the preconditioner can be reused for the subsequent stages of the Rosenbrock-Wanner scheme. Unsteady flow simulations show a gain in computational efficiency of approximately factor three to five in comparison with ESDIRK

Aspects of goal-oriented model-error estimation in convection-diffusion problems

For goal-oriented model adaptation a model-error estimator is required to drive the adaptation process. In recent years publications have appeared on the dual-weighted residual (DWR) method in the application of model-error estimation in output functionals. In this paper we study the application of the DWR method for convection-diffusion problems where hierarchical models are of different type. Omitting the diffusion operator often results in a singular perturbation problem considering the model residual in the limit of vanishing diffusion. This is caused by the change of mathematical type of the model equations and therefore the applied boundary conditions. In this work we show how a model error estimator is developed for steady and unsteady convection-diffusion problems. It is found that a weak formulation and weakly imposing boundary and initial conditions leads to a dual-weighted model-error estimator that also incorporates boundary residuals

A multi-model incremental adaptive strategy to accelerate partitioned fluid-structure algorithms using space-mapping

High fidelity analysis of fluid-structure interaction systems is often too timeconsuming when a large number of model evaluations are required. The choice for a solution procedure depends often on the efficiency of the method and the possibility of reusing existing field solvers. Aggressive Space-Mapping, a technique originally developed for multi-fidelity optimization, is applied to accelerate the partitioned solution procedure of a high fidelity fluid-structure interaction model. The method supports software modularity. Aggressive Space-Mapping (ASM) is applied to an academic testcase and the results are compared with the corresponding Incremental Quasi-Newton (IQN) method. An efficiency metric is defined to facilitate the comparison. The ASM method is found to be more efficient than the corresponding IQN method for the testcases considered. The efficiency of space-mapping increases with increasing fluid-to-structure mass ratio, indicating that the method is especially useful for strongly coupled problems

FLECS, a flexible coupling shell, application to fluid-structure interaction

Numerical simulations involving multiple, physically different domains can be solved effectively by coupling simulation programs, or solvers. The coordination of the different solvers is commonly handled by a coupling shell. A coupling shell synchronizes the execution of the solvers and handles the transfer of data from one physical domain to another. In this paper, we introduce Flecs, a flexible coupling shell, designed for implementing and applying an interface for multidisciplinary simulations with superior accuracy. The aim is not to achieve the best possible efficiency or to support a large feature set, but to provide a flexible platform for developing new data transfer algorithms and coupling schemes