On Bending of Bernoulli-Euler Nanobeams for Nonlocal Composite Materials

Evaluation of size effects in functionally graded elastic nanobeams is carried out by making recourse to the nonlocal continuum mechanics. The Bernoulli-Euler kinematic assumption and the Eringen nonlocal constitutive law are assumed in the formulation of the elastic equilibrium problem. An innovative methodology, characterized by a lowering in the order of governing differential equation, is adopted in the present manuscript in order to solve the boundary value problem of a nanobeam under flexure. Unlike standard treatments, a second-order differential equation of nonlocal equilibrium elastic is integrated in terms of transverse displacements and equilibrated bending moments. Benchmark examples are developed, thus providing the nonlocality effect in nanocantilever and clampled-simply supported nanobeams for selected values of the Eringen scale parameter

a note on torsion of nonlocal composite nanobeams

The ERINGENelastic constitutive relation is used in this paper in order to assess small-scale effects in nanobeams. Structural behavior is studied for functionally graded materials in the cross-sectional plane and torsional loading conditions. The governing boundary value problem has been formulated in a mixed framework. Torsional rotations and equilibrated moments are evaluated by solving a first-order differential equation of elastic equilibrium with boundary conditions of kinematic-type. Benchmarks examples are briefly discussed, enlightening thus effectiveness of the proposed methodology

Mechanical behavior of web-flange junctions of thin-walled pultruded fiber-reinforced polymer profiles: an experimental and numerical evaluation

2012 - 2013Fibre-reinforced polymer (FRP) composites represent a class of advanced materials whose use has spread from the aeronautical, mechanical and naval industry to civil infrastructure, which has generated a new set of challenges. Composites have unique features, such as high corrosion resistance, electromagnetic transparency, low maintenance costs and high strength-to-weight ratio. During the past few decades, pultruded fibre-reinforced polymer (PFRP) composites have been used in several successful applications related to corrosive environments such as cooling towers, mining and petrochemical facilities, water and wastewater treatment plants, as well as, off-shore structures. By mid-1990s, major applications of these materials were initiated in the field of seismic and corrosion repair and strengthening of existing reinforced concrete bridges and buildings. Historically, off-the-shelf PFRP composites were developed and designed by the pultrusion industry and were intended for low-stress applications. Recently, composites have been introduced as primary structural members to replace or complement other conventional materials, such as steel, concrete and wood, in critical applications such as bridge decks, pedestrian bridges, and recently in highway bridges and other infrastructural systems. ... [edited by Author]XII n.s

Non-typhoidal Salmonella septic arthritis in an immunocompetent child with a pharyngeal streptococcal infection

Summary We report the case of an immunocompetent child who showed monoarticular arthritis and fever, preceded by pharyngitis and arthralgias. Because group A β-hemolytic Streptococcus had been detected in the pharyngeal swab, erythromycin was given on admission. However, based on ultrasound examination, therapy with ceftriaxone and joint fluid drainage were promptly performed, and a rapid and full recovery followed. Meanwhile, Salmonella enterica infection was revealed in blood and joint fluid. Our case suggests that septic arthritis caused by a non-typhoidal Salmonella infection may occur without gastrointestinal manifestations and concomitantly with a pharyngeal streptococcal infection

Heterogeneity and instability : theoretical–methodological outcomes of three investigations on land and agrarian movements and the state

The article presents a theoretical–methodological proposal to research movements and its connections based on the associations they estab-lish. The first investigation focuses on the transformations of the South African Landless People’s Movement, the second on interactions between Brazilian rural movements and the National Institute of Colonization and Agrarian Reform, the third focuses on the transnational ties of the Brazilian National Confederation of Agricultural Workers. We pro-duce an ontological definition of movements and the state as collectives whose existence is defined by continuous assemblages of heterogene-ous and unstable elements. Those collectives are not enclosed analytical units, but contingent and contextual. Methodologically, we suggest the observation of the processes in the long term to grasp the continu-ous constructions of those collectives, even before they reach public expression. Controversies are analytical categories for understanding which elements allow things to take the course we analyze

Nano-beams under torsion: a stress-driven nonlocal approach

Purpose This study aims to model scale effects in nano-beams under torsion. Design/methodology/approach The elastostatic problem of a nano-beam is formulated by a novel stress-driven nonlocal approach. Findings Unlike the standard strain-driven nonlocal methodology, the proposed stress-driven nonlocal model is mathematically and mechanically consistent. The contributed results are useful for the design of modern devices at nanoscale. Originality/value The innovative stress-driven integral nonlocal model, recently proposed in literature for inflected nano-beams, is formulated in the present submission to study size-dependent torsional behavior of nano-beams

Experimental investigation on cyclic response of RC elements repaired by CFRP external reinforcing systems

This paper deals with the experimental results of an investigation aimed at studying cyclic response of half scaled RC specimens previously damaged and then repaired with externally bonded carbon fiber reinforced polymer sheets. The research involved the test of ten specimens. Two of them were tested without any external strengthening material in order to provide a reference for the response of repaired specimens. These latter were tested after a previous damaging procedure and a subsequent repair intervention with fiber reinforced polymer composites. The parameters under investigation were the level of initial damage, the strengthening configuration, and the level of axial load. Test results have pointed out effectiveness of the adopted strengthening systems, since repaired specimens exhibited better mechanical responses than the unstrengthened ones

El mundo raro de Mermel. Propuestas didácticas para abordar las diversidades y disidencias en Infantil y Primaria.

De la mano de Mermel y su pandilla, estudiantes y personal docente podrán abordar cuestiones de género, identidades, roles, vio­lencias, diferencias, cuerpos, culturas y etnias variadas, formas de hacer y de estar en el mundo, capacidades, prevención de la violencia y de situa­ciones de acoso entre iguales y el abuso de menores. Incorpora, además, elementos sobre el desarrollo sostenible, la ecolo­gía, los cuidados, la crítica al consumo o al propio sistema capitalista o el desarrollo de actitudes de respeto, siempre desde la prevención

Los movimientos y el estado como colectivos inestables y heterogéneos : una agenda teórico-metodológica basada en tres estudios de caso

Neste texto apresenta-se uma proposta teórico-metodológica para pesquisar movimentos e estado tomando como base as associações que estabelecem a partir de três pesquisas: sobre as transformações do Landless People’s Movement (LPM) da África do Sul, as interações entre movimentos rurais brasileiros e o Instituto Nacional de Colonização e Reforma Agrária (Incra) na implementação da política de reforma agrária, e a transnacionalização da Confederação Nacional dos Trabalhadores na Agricultura (Contag). O principal efeito do artigo é uma definição ontológica de movimentos e do estado como coletivos cuja existência é marcada por contínuos agenciamentos de elementos heterogêneos e instáveis. Não sendo possível tomá-los como unidades analíticas fechadas, cabe às pesquisas observar construções contínuas de grupos e coletivos contingentes às associações contextuais que se formam – desde antes, portanto, de sua expressão pública. Para tanto, propõe-se que sejam compreendidos quais elementos, agenciados de forma específica e descritível, permitem que as coisas tomem os cursos que normalmente observamos e analisamos. Sugere-se ainda o emprego metodológico das controvérsias como categorias analíticas e a observação dos processos na longa duração.This paper presents a theoretical-methodological proposal to re-search movements and the state based on the associations they establish. It is grounded in three investigations: the first one about the transformations of the Landless People’s Movement (LPM) of South Africa, the second about interactions between Brazilian rural movements and the National Institute of Colonization and Agrarian Reform (Incra); the third focuses on the transnational ties of the National Confederation of Agricultural Workers (Contag). The main effect of the article is an ontological definition of movements and the state as collectives whose existence is defined by continuous assemblages of heterogeneous and unstable elements. Since it is not possible to take them as enclosed analytical units, it is up to the research to observe continuous constructions of groups and collectives which are contingent and contextual. Researchers will often follow these processes before their public expression. The proposal is to understand which elements allow things to take the courses we normally observe and analyze. It is also su-ggested the methodological use of controversies as analytical categories and the observation of the processes in the long term.Este texto presenta una propuesta teórico--metodológica para investigar movimientos y el estado basada en las asociaciones que establecen a partir de tres investigaciones: sobre las transformaciones del Landless People’s Movement (LPM) de Sudáfrica, las interacciones entre movimientos rurales de Brasil y el Instituto Nacional de Colonización y Reforma Agraria (Incra) en la implementación de la política de reforma agraria, y, por ende, la transnacionalización de la Confe-deración Nacional de Trabajadores Agrícolas (Contag). El efecto principal del artículo es una definición ontoló-gica de los movimientos y del estado como colectivos cuya existencia está marcada por conjuntos continuos de elementos heterogéneos e inestables. Dado que no es posible tomarlos como unidades analíticas cerradas, corresponde a las investigaciones observar construc-ciones continuas de grupos y colectivos supeditados a las asociaciones contextuales que se forman, desde antes de su expresión pública. Con este fin, se propone comprender qué elementos, organizados de manera específica y descriptiva, permiten que las cosas tomen los cursos que normalmente observamos y analizamos. También se sugiere el uso metodológico de contro-versias como categorías analíticas y la observación de los procesos a largo plazo