495 research outputs found

    Analysis of laminated beams using the natural neighbour radial point interpolation method

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    Neste trabalho aplica‐se o método sem malha natural neighbour radial point interpolation method (NNRPIM) à análise unidimensional de vigas laminadas, considerando a teoria de Timoshenko. O NNRPIM combina o conceito matemático dos vizinhos naturais com a interpolação radial pontual. Os diagramas de Voronoï permitem impor a conectividade nodal e construir a malha de fundo para efeitos de integração, por intermédio das células de influência. É apresentada a construção das funções de interpolação NNRPIM, sendo, para estas, usada a função de base radial multiquadrática. As funções de interpolação geradas possuem continuidade infinita e a propriedade de delta Kronecker, o que facilita a imposição das condições de fronteira, uma vez que estas podem ser impostas com o método da imposição direta, tal como no método dos elementos finitos (FEM). De modo a obter o campo de deslocamentos e de deformações, a teoria de deformação de Timoshenko para vigas sujeitas a esforços transversos é considerada. Vários exemplos numéricos de vigas isotrópicas e vigas laminadas são apresentados de modo a demonstrar a convergência e a exatidão da aplicação proposta. Os resultados obtidos são comparados com soluções analíticas disponíveis na literatura.In this work, a meshless method, “natural neighbour radial point interpolation method” (NNRPIM), is applied to the one‐dimensional analysis of laminated beams, considering the theory of Timoshenko. The NNRPIM combines the mathematical concept of natural neighbours with the radial point interpolation. Voronoï diagrams allows to impose the nodal connectivity and the construction of a background mesh for integration purposes, via influence cells. The construction of the NNRPIM interpolation functions is shown, and, for this, it is used the multiquadratic radial basis function. The generated interpolation functions possess infinite continuity and the delta Kronecker property, which facilitates the enforcement of boundary conditions, since these can be directly imposed, as in the finite element method (FEM). In order to obtain the displacements and the deformation fields, it is considered the Timoshenko theory for beams under transverse efforts. Several numerical examples of isotropic beams and laminated beams are presented in order to demonstrate the convergence and accuracy of the proposed application. The results obtained are compared with analytical solutions available in the literature.Peer Reviewe

    Effect of the particle size range of construction and demolition waste on the fresh and hardened-state properties of fly ash-based geopolymer mortars with total replacement of sand

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    This study seeks the valorization of industrial residues (fly ash and construction and demolition waste (CDW)) through the production of geopolymer mortars. The effect of the sand substitution by CDW and the influence of the particle size range of CDW fine aggregates on the fresh and hardened properties of the mortars were evaluated. Geopolymer mortars were produced using biomass fly ash waste and metakaolin as a binder, CDW as fine aggregates, and an alkali solution of sodium silicate and sodium hydroxide as activator. The geopolymer mortars were characterized in fresh state by the flow table test and in the hardened state through chemical, physical/microstructural analyzes. The mortars produced with CDW showed lower flowability when compared to the ones prepared with sand. The compressive and flexural strength of hardened mortars, respectively, obtained with residues were higher when compared to sand: 40 MPa and 8.5 MPa with CDW, against 23 MPa and 3.1 MPa for sand-based samples. It was observed that mortars developed with recycled aggregate and natural aggregate present similar chemical and mineralogical compositions. The superior results obtained in the mechanical properties of mortars produced with CDW are related to the recycled aggregate-geopolymer paste interface.publishe

    Improving environmental sustainability of agriculture in Egypt through a life-cycle perspective

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    Soil plays an essential role as a habitat, source of nutrients and support for vegetation. Promoting food security and environmental sustainability of agricultural systems requires an integrated approach to soil fertility management. Agricultural activities should be developed with preventive approaches aimed at avoiding or reducing negative impacts on the soil physicochemical and biological properties and the depletion of soil nutrient reserves. In this regard, Egypt has developed the Sustainable Agricultural Development Strategy to encourage environmentally friendly practices among farmers, such as crop rotation and water management, in addition to extending agriculture to desert areas, favoring the socio-economic development of the region. In order to evaluate the outcomes of the plan beyond quantitative data of production, yield, consumption and emissions, the environmental profile of agriculture in Egypt has been assessed under a life-cycle perspective in order to identify the associated environmental burdens and ultimately contribute to improving the sustainability policies of agricultural activity within the framework of a crop rotation system. In particular, a two-year crop rotation (Egyptian clover-maize-wheat) was analyzed in two distinct agricultural areas in Egypt: New Lands in desert regions and Old Lands along the Nile River, traditionally recognized as fertile areas due to the river alluvium and water availability. The New Lands had the worst environmental profile for all impact categories, except for Soil organic carbon deficit and Global potential species loss. Irrigation and on-field emissions associated with mineral fertilization were identified as the most critical hotspots of Egyptian agriculture. In addition, land occupation and land transformation were reported as the main drivers of biodiversity loss and soil degradation, respectively. Beyond these results, further research on biodiversity and soil quality indicators is needed to more accurately assess the environmental damage caused by the conversion of deserts into agricultural areas, given the species richness these regions holdThis research is supported by the project Enhancing diversity in Mediterranean cereal farming systems (CerealMed), funded by PRIMA Programme, FEDER/Ministry of Science and Innovation– Spanish National Research Agency (PCI2020-111978); and Academy of Scientific Research and Technology (ASRT); and the project Transition to sustainable agri-food sector bundling life cycle assessment and ecosystem services approaches (ALISE), funded by the Spanish National Research Agency (TED2021-130309B-I00). S.L.O., M.T.M. and S.G.G belong to the Galician Competitive Research Group (GRC ED431C-2021/37) and to the Cross-disciplinary Research in Environmental Technologies (CRETUS Research Center, ED431E 2018/01)This research is supported by the project Enhancing diversity in Mediterranean cereal farming systems (CerealMed), funded by PRIMA Programme, FEDER/Ministry of Science and Innovation– Spanish National Research Agency (PCI2020-111978); and Academy of Scientific Research and Technology (ASRT); and the project Transition to sustainable agri-food sector bundling life cycle assessment and ecosystem services approaches (ALISE), funded by the Spanish National Research Agency (TED2021-130309B-I00). S.L.O., M.T.M. and S.G.G belong to the Galician Competitive Research Group (GRC ED431C-2021/37) and to the Cross-disciplinary Research in Environmental Technologies (CRETUS Research Center, ED431E 2018/01)S

    Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal

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    Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal Cátia Coelho2, Elsa Caeiro2,4, Maria Luísa Lopes1, Ana Filipa Lopes3, Raquel Ferro2, José Eduardo Moreira3, Célia Antunes3,4, Rui Brandão4,5 1Hospital de Santa Luzia, Elvas, Portugal; 2Sociedade Portuguesa de Alergologia e Imunologia Clínica (SPAIC), Lisboa, Portugal; 3Departamento de Química, Universidade de Évora, Portugal; 4Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Portugal; 5 Departamento de Biologia, Universidade de Évora, Portugal Introdução: A sensibilização aos pólenes depende de vários factores nomeadamente do tipo de vegetação local e sabe-se que a sintomatologia não está apenas associada à exposição aos pólens mas também a partículas, algumas das quais resultantes da rotura dos grãos de pólen sendo posteriormente aerossolizadas. Objectivos: Relacionar a sensibilização de doentes com a concentração polínica atmosférica e a concentração de alguns dos respectivos aerolergenos. Métodos: Das consultas externas de Imunoalergologia dos hospitais de Évora e Elvas seleccionaram-se doentes que apresentavam queixas sazonais de rinite alérgica e asma brônquica, aos quais foram realizados testes cutâneos em Prick, standardizados, aos pólenes identificados na região. A 55 doentes foram realizados testes ao extracto de Phleum, aos seus alergénios Phl p 1 e Phl p 5, bem como aos extractos das restantes gramíneas e a 47 doentes foram realizados testes ao extracto de Olea, aos seus alergénios Ole e 1 e Ole e 2. Monitorizaram-se diariamente as partículas polínicas e os aeroalergenos mediante 2 colectores específicos para cada tipo. Resultados: A percentagem de doentes que é sensível aos 3 extractos de Phleum (Phleum total, Phl p 1 e Phl p 5) é de 51% , a dos que são sensíveis aos extractos de Phleum total e Phl p 1 é de 16 % e a dos que são sensíveis a Phleum total e Phl p5 é de 2%. A percentagem de doentes que é sensível a somente um dos extractos é de 20% e os que não têm qualquer sensibilidade são 11%. A percentagem de doentes que é sensível aos 3 extractos de Olea (Olea total, Ole e 1 e Ole e 2) é de 23%, a dos que são sensíveis à Olea total e Ole e 1 é de 21 % e a dos que são sensíveis à Olea total e Ole e 2 é de apenas 4%. A percentagem dos que são sensíveis a um dos extractos é de 19% e a dos que não apresentaram qualquer sensibilidade é de 32%. Conclusões: Podemos concluir que 89% dos doentes mostraram ser sensíveis aos alergénios da gramínea Phleum pratense pois mostraram positividade tanto ao extracto de Phleum e/ou aos seus alergénios Phl p 1 e Phl p 5. Em relação à oliveira, 44% dos doentes são alérgicos a este pólen pois são sensíveis ao seu alergénio major, Ole e 1. Em ambos os casos estão correlacionados com os aeroalergenos detectados nas amostras de ar, sendo a sensibilidade aos pólenes de gramíneas maior que a sensibilidade ao pólen de oliveira. Mais estudos devem ser realizados para despiste de reacções cruzadas nomeadamente quanto à Olea com outras plantas da região

    Determinação da Carga Alergénica (Ole e1) Presente no Ar Atmosférico na Região de Évora: Correlação com o conteúdo polínico de Olea

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    Introdução: Em Portugal, o pólen da oliveira (Olea europaea) constitui uma das fontes mais relevantes de aero-alergénios, sendo uma causa frequente de polinose na região Mediterrânica, onde o Ole e 1 é um alergeno major. Apesar de se julgar apenas associado aos grãos de pólen, desconhece-se a variabilidade inter-anual da carga alergénica do pólen e ainda existe alguma controvérsia sobre a forma como este aeroalergeno se distribui no ar atmosférico. Objectivo: Este trabalho teve como objectivos: i) determinar a fracção dos bioaerossóis mais rica em Ole e 1; ii) avaliar a correlação dos conteúdos diários de pólen e aeroalergeno no ar atmosférico; iii) avaliar variação anual da carga alergénica do pólen. Métodos: Os aeroalergenos foram captados utilizando um colector de impacto CHEMVOL equipado com dois filtros com capacidade para reter partículas de diferentes dimensões: PM>10µm e 10µm>PM>2,5µm. Após 24h os filtros foram retirados, a fracção proteica foi extraída e os alergenos quantificados por ELISA. Simultaneamente o pólen foi monitorizado pela tecnologia padrão utilizando um colector volumétrico Burkard 7-Day Recording Volumetric Spore Trap. Os colectores foram ambos colocados numa mesma plataforma a 17m de altura, e a ≈3-4m um do outro. Resultados: Entre 2009 e 2011, registou-se uma variação inter-anual quer do perfil quer da duração da época polínica (39, 47 e 45 dias, respectivamente). O conteúdo polínico total no ar atmosférico também foi variável no intervalo de 7240 a 12524 grãos/m3. Mais de 90% do alergeno foi encontrado na fracção de bioaerossóis de PM>10µm. O conteúdo em Ole e 1 foi directamente proporcional ao número de grãos de pólen no ar atmosférico, tendo-se encontrado uma correlação positiva entre os valores diários dos dois parâmetros. Comparando as épocas estudadas, os conteúdos totais de Ole e1 e de pólen não foram proporcionais, tendo-se observado que a carga alergénica por grão de pólen variou mais de 3x. Conclusões: Estes resultados sugerem que o Ole e 1 está preferencialmente associado aos grãos de pólen. Os conteúdos em pólen e Ole e 1 variaram inter-anualmente, tendo a carga alergénica dos grãos de pólen sido diferente. Este trabalho poderá assim contribuir para o desenvolvimento de um indicador que permita melhorar a previsão do risco de exposição a aeroalergenos. Agradecimentos: Este foi realizado no âmbito do projecto europeu HIALINE (Executive Agency for Health and Consumers, grant agreement No 2008 11 07)

    Novel universality class of absorbing transitions with continuously varying critical exponents

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    The well-established universality classes of absorbing critical phenomena are directed percolation (DP) and directed Ising (DI) classes. Recently, the pair contact process with diffusion (PCPD) has been investigated extensively and claimed to exhibit a new type of critical phenomena distinct from both DP and DI classes. Noticing that the PCPD possesses a long-term memory effect, we introduce a generalized version of the PCPD (GPCPD) with a parameter controlling the memory effect. The GPCPD connects the DP fixed point to the PCPD point continuously. Monte Carlo simulations show that the GPCPD displays novel type critical phenomena which are characterized by continuously varying critical exponents. The same critical behaviors are also observed in models where two species of particles are coupled cyclically. We suggest that the long-term memory may serve as a marginal perturbation to the ordinary DP fixed point.Comment: 13 pages + 10 figures (Full paper version

    The fraction of cancer attributable to ways of life, infections, occupation, and environmental agents in Brazil in 2020

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    Many human cancers develop as a result of exposure to risk factors related to the environment and ways of life. The aim of this study was to estimate attributable fractions of 25 types of cancers resulting from exposure to modifiable risk factors in Brazil. The prevalence of exposure to selected risk factors among adults was obtained from population-based surveys conducted from 2000 to 2008. Risk estimates were based on data drawn from metaanalyses or large, high quality studies. Population-attributable fractions (PAF) for a combination of risk factors, as well as the number of preventable deaths and cancer cases, were calculated for 2020. The known preventable risk factors studied will account for 34% of cancer cases among men and 35% among women in 2020, and for 46% and 39% deaths, respectively. The highest attributable fractions were estimated for tobacco smoking, infections, low consumption of fruits and vegetables, excess weight, reproductive factors, and physical inactivity. This is the first study to systematically estimate the fraction of cancer attributable to potentially modifiable risk factors in Brazil. Strategies for primary prevention of tobacco smoking and control of infection and the promotion of a healthy diet and physical activity should be the main priorities in policies for cancer prevention in the country. \ua9 2016 Azevedo e Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Effective treatment of a case of pregnancy toxemia in sheep - case report

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    ABSTRACT Pregnancy toxemia has a high mortality rate and few cases with effective treatment are reported, especially when associated with secondary diseases. Therefore, the present work reports the case of a sheep, which was referred to the veterinary hospital of UFMG, in the last month of pregnancy, presenting apathy, hyporexia and sternal recumbency. After the diagnosis of pregnancy toxemia, the fetuses were removed while still alive, but did not survive. Monitoring was started with blood gas analysis, blood glucose assessments and laboratory tests. The results were consistent with liver damage, which was justified by the condition of lipolysis. Treatment consisted of electrolyte replacement plus 50% glucose and potassium chloride, along with administration of antibiotics (ceftiofur, 5mg/kg/SID/IM/7 days), flunixim meglumine (2.2mg/kg/SID/IM first day and 1.1mg/kg/SID/IM on the second and third days) and omeprazole (4mg/kg/SID/oral). The patient had secondarily clinical laminitis, which was treated with cryotherapy and anti-inflammatory drugs, in addition to mastitis, using a single dose of intramammary antibiotics. The work demonstrated the effectiveness of the treatment of pregnancy toxemia, when performed early and intensively, associated with daily clinical and laboratory monitoring of the animal
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