Evaluation of the inelastic behavior of steel columns and frames subjected to minor‐axis bending

Este trabalho tem como objetivo avaliar o comportamento inelástico de sistemas estruturais metálicos submetidos à flexão em torno do eixo de menor inércia. Consideram‐se seções transversais compactas do tipo I. Nessas seções, a flexão em torno do eixo mais fraco apresenta benefícios importantes como a capacidade de desenvolver toda resistência plástica sem ocorrência de flambagem lateral por torção. Adota‐se uma formulação de elementos finitos reticulados planos, na qual o processo de plastificação do aço é acompanhado através do método da rótula plástica refinado. Nesse método, os efeitos decorrentes do escoamento do material são capturados através de um parâmetro que reduz a rigidez do membro estrutural em função do desenvolvimento de regiões plásticas. Emprega‐se ainda nesse método o módulo tangente para considerar a degradação da rigidez em função das forças internas. Efeitos de segunda ordem, tensões residuais e imperfeições geométricas também são considerados nas análises. Como critério para definir o estado limite último de resistência da seção transversal adotam‐se superfícies de plastificação que descrevem a interação entre esforço normal e momento fletor. Para solução das equações não lineares de equilíbrio estrutural usa‐se o método de Newton‐Raphson acoplado a estratégias de continuação. Colunas isoladas e pórticos planos são analisados e os resultados obtidos são comparados aos encontrados por outros pesquisadores. Essas comparações permitem concluir que as técnicas usadas neste trabalho são eficazes e necessárias para uma melhor previsão do comportamento das estruturas com membros submetidos à flexão em torno do eixo de menor inércia.This work presents an evaluation of the inelastic behavior of steel structures subjected to minor‐axis bending. Profiles type I and compact cross‐sections are considered. In these sections, the bent about weak axis presents important benefits, such as the ability to develop all of their plastic resistance without the occurrence of lateral torsional buckling. A nonlinear beam‐column element formulation is adopted, in which the steel yielding process is accounted by the refined plastic‐hinge method. In this method the effects of material yielding are captured by a parameter that reduces the structural member stiffness with the development of cross‐section plastic regions. The tangent modulus approach is used to consider the stiffness degradation caused by the increase in internal forces. Second–order effects, residual stresses and geometric imperfections are also considered in analysis. To define the cross‐section strength ultimate limit state, the study adopts strength surfaces that describe the interaction between internal forces — axial force and bending moment. The nonlinear equations at the structural system level are solved using the Newton‐Raphson iterative strategy coupled with path‐following methods. Isolated steel columns and portal frames are analyzed, and the results obtained are compared to those of other investigators. The comparison shows that the numerical methodology presented in this work is effective and can be used for predicting the behavior of steel structures with members under minor‐axis bending.Peer Reviewe

1-[2-(4-methyl-7-coumarinyloxy)ethyl]-4-(5-{1-[2-(4-methyl-7-coumarinyloxy)ethyl]-1h-1, 2, 3-triazol-4-yl}pentyl)-1h-1, 2, 3-triazole

Nature often produces compounds with a high degree of symmetry to reduce structural information and complexity. Synthesis of identical twin drugs, through the linkage of two identical pharmacophoric entities, is a classical strategy to produce more potent and/or selective drugs. Herein, two units of the privileged core of the coumarin hymecromone were linked together using “click chemistry”. Synthesis of 1-[2-(4-Methyl-7-coumarinyloxy)ethyl]-4-(5-{1-[2-(4-methyl- 7-coumarinyloxy)ethyl]-1H-1, 2, 3-triazol-4-yl}pentyl)-1H-1, 2, 3-triazole was achieved by coupling of two identical units of an azido coumarin with a symmetrical alkine using copper(I)-catalyzed alkyne-azide cycloaddition reaction, in good yields and with complete regioselectivity. © 2016 by the authors; licensee MDPI, Basel, Switzerland.2016

Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water

The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio

A comprehensive review on carotenoids in foods and feeds: status quo, applications, patents, and research needs

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN, www.eurocaroten.eu, https://www.cost.eu/actions/CA15136/#tabs|Name:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.This article is based upon work from COST Action (European network to advance carotenoid research and applications in agro-food and health, EUROCAROTEN, CA15136, www.eurocaroten.eu, https://www. cost.eu/actions/CA15136/#tabsjName:overview) supported by COST (European Cooperation in Science and Technology, http://www.cost. eu/).info:eu-repo/semantics/publishedVersio

Avaliação do uso de resíduo de serragem de pedra Cariri (RSPC) para produção de concretos convencionais

No estado do Ceará, na região do Cariri, um minério calcário laminado, comercialmente conhecido como pedra Cariri, é muito explorado. Os processos de exploração e beneficiamento desse minério são causas da geração de resíduos. Um dos tipos de resíduo gerado é o decorrente da serragem de pedra Cariri, denominado de resíduo de serragem de pedra Cariri (RSPC). Nesta pesquisa, avalia-se a viabilidade do uso de RSPC como substituição parcial do cimento na produção de concretos convencionais. Foram determinadas as características químicas e físicas do RSPC. A influência foi avaliada através das propriedades mecânicas (resistência à compressão axial e diametral) e parâmetros de durabilidade (absorção por imersão e por sucção capilar). Foram produzidos 9 traços, variando a relação a/c (0,45; 0,55; 0,65) e os teores de substituição (0%, 10% e 20%) do cimento. Os resultados demonstram que a utilização de RSPC no concreto proporcionou uma redução nas resistências à compressão e à tração por compressão diametral. Entretanto, em relação aos parâmetros de durabilidade, os concretos com RSPC apresentaram comportamento compatível com os concretos de referência. De um modo geral, do ponto de vista técnico, o RSPC não proporcionou resultados satisfatórios para aplicação em concreto