24 research outputs found

    Conhecimentos dos alunos em Educação Física: Um estudo quasi-experimental com intervenção

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    Orientação: Francisco Alberto Arruda Carreiro da CostaO decréscimo de Atividade Física (AF) e os poucos conhecimentos adquiridos em Educação Física (EF) apresentados pela população escolar devem ser encarados como uma atual e alarmante preocupação para o futuro. O objetivo do estudo foi analisar os conhecimentos dos alunos do secundário relativamente à Educação Física relacionada com a saúde e avaliar o efeito de uma sessão de ensino teórico sobre o seu nível de conhecimento, designadamente as recomendações para a prática de AF. Participaram no estudo 72 alunos (Masculino=30, Feminino=42) de uma escola secundária. Os alunos foram divididos em dois grupos: o G1, para efeitos de estudo, foi definido como o Grupo de Controlo (GC) e o G2 como Grupo de Intervenção (GI). Num primeiro momento, foi aplicado aos dois grupos um questionário de avaliação de conhecimentos. Não se verificaram diferenças estatisticamente significativas entre os dois grupos. O GI foi submetido a uma intervenção teórica onde foram abordados conteúdos relacionando a aptidão física e a saúde e identificados os fatores associados a um estilo de vida saudável. Uma semana após a intervenção foi aplicado o questionário de avaliação de conhecimentos a ambos os grupos. Três semanas após a intervenção foi aplicado novamente o questionário apenas ao GI com o intuito de avaliar a retenção dos conhecimentos adquiridos. Os alunos do GI registaram uma evolução positiva nos seus conhecimentos registando-se uma maior percentagem de respostas corretas nas recomendações de AF quanto à intensidade, duração e tempo, benefícios da AF e perigos associados à inatividade física. Os alunos do GC mantiveram ao longo do estudo os mesmos conhecimentos. Os resultados deste estudo enfatizam a necessidade dos Professores de Educação Física utilizarem nas aulas estratégias que promovam, junto dos alunos, os conhecimentos que lhes permitam adotar, de forma consciente, um estilo de vida ativo e saudável ao longo da vida.The decrease in Physical Activity (AF) and the little knowledge acquired in Physical Education (PE) presented by the school population should be viewed as a current and alarming concern for the future. The objective of the study was to analyze the knowledge of the secondary students regarding Physical Education related to health and to evaluate the effect of a theoretical teaching session on their level of knowledge, namely the recommendations for the practice of PA. The study involved 72 students (Male = 30, Female = 42) from a secondary school. The students were divided in two groups: G1, for study purposes, was defined as the Control Group (CG) and G2 as the Intervention Group (GI). At first, a knowledge assessment questionnaire was applied to both groups. There were no statistically significant differences between the two groups. The GI was submitted to a theoretical intervention in which contents related to physical fitness and health were addressed and the factors associated with a healthy lifestyle were identified. One week after the intervention, the knowledge assessment questionnaire was applied to both groups. Three weeks after the intervention, the questionnaire was applied again only to the GI in order to evaluate the retention of the acquired knowledge. GI students had a positive evolution in their knowledge, with a higher percentage of correct answers in FA recommendations regarding intensity, duration and time, FA benefits, and hazards associated with physical inactivity. The students of the GC kept the same knowledge throughout the study. The results of this study emphasize the need for Physical Education Teachers to use, in their classes, strategies that promote knowledge among students and enable them to consciously adopt an active and healthy lifestyle throughout their lives

    Flexural strengthening of RC slabs with prestressed CFRP strips: serviceability and ultimate load state behavior

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    O presente trabalho pretende contribuir para o conhecimento da técnica EBR (Externally Bonded Reinforcement) usando laminados de CFRP (Carbon Fiber-Reinforced Polymer) pré-esforçados no reforço à flexão de estruturas de betão, sob condições de serviço (SLS) e estado limite último (ULS). Para tal, foi desenvolvido um programa experimental composto por 8 lajes ensaiadas até à rotura. Duas lajes foram usadas como de referência; 5 reforçadas com laminados de EBR/CFRP pré-esforçados; finalmente, 1 laje reforçada com um laminado EBR/CFRP. Dois sistemas distintos de ancoragem foram estudados: MA (Mechanical Anchorage) e GA (Gradient Anchorage). O efeito da largura e espessura do laminado foi também estudado. A performance dos protótipos é criticamente analisada ao nível dos SLS e ULS.The present work intends to contribute to the knowledge of Externally Bonded Reinforcement (EBR) technique using prestressed Carbon Fiber-Reinforced Polymer laminates (CFRP) to strengthen concrete structures in flexure, at both serviceability (SLS) and ultimate load levels (ULS). For that purpose, an experimental program was carried out with 8 slabs monotonically tested under displacement control up to failure. Two slabs were used as reference specimens (unstrengthened); 5 slabs were strengthened with prestressed EBR CFRP laminates; finally, 1 slab was strengthened EBR CFRP laminates without being prestressed. To fix the ends of the prestressed CFRP laminates two different anchorage systems were used: Mechanical Anchorage (MA) and Gradient Anchorage (GA). The effect of the width and thickness of the CFRP laminate were also studied. The observed performance of the tested slabs is critically analyzed in terms of SLS and ULS aspects

    Flexural creep response of hybrid GFRP–FRC sandwich panels

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    This work was developed within the scope of the research project “Easyfloor—Development of composite sandwich panels for building floor rehabilitation”, which aims at developing an innovative hybrid sandwich panel as an alternative construction system to conventional floor solutions, mainly for building rehabilitation. The developed hybrid sandwich panel is composed of a top face layer of steel-fibre-reinforced self-compacting concrete (FRC), a core of polyurethane (PUR) closed-cell foam, a bottom face sheet, and lateral webs of glass-fibre-reinforced polymer (GFRP). Full-scale experimental tests on the developed sandwich panels were carried out to characterize their short- and long-term (creep) flexural behaviour. The present work includes a detailed description of the developed panels and the experimental programme carried out and presents and discusses the relevant results. The experimental results showed an almost linear behaviour up to failure. The creep tests were carried out for a period of 180 days, using a creep load equal to 20% of its ultimate loading capacity. An average creep coefficient of 0.27 was obtained for this period. The composed creep model used to simulate the sandwich panel’s creep deflections by considering the individual viscoelastic contributions was able to predict the observed structural response with good accuracy.project “32EasyFloor—Development of composite sandwich panels for rehabilitation of floor buildings”, involving the company ALTO—Perfis Pultrudidos, Lda., ISISE/University of Minho, and CERis/Instituto Superior Técnico, supported by FEDER funds through the Operational Program for Competitiveness and Internationalization (POCI) and the Portuguese National Innovation Agency (ANI)—project no. 3480 (POCI-01-0247-FEDER-003480). This work was also partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020

    Reforço à flexão de lajes de betão armado com laminados de CFRP pré-esforçados : comportamento em estado limite último e de utilização

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    No contexto do reforço estrutural à flexão com recurso aos laminados de CFRP (Carbon Fiber-Reinforced Polymers), a técnica EBR (Externally Bonded Reinforcement) é frequentemente utilizada. A aplicação de CFRP pré-esforçados acumula as vantagens da técnica EBR com as do pré-esforço externo. O sistema de ancoragem desempenha um papel fundamental nos sistemas de reforço com laminados de CFRP pré-esforçados. Por esta razão, neste trabalho desenvolveu-se um programa experimental, composto por 8 lajes de betão armado, com o principal objetivo de analisar dois sistemas de ancoragem: (i) ancoragem metálica e (ii) ancoragem do gradiente de força. Além dos sistemas de ancoragem, foi também analisada a influência da geometria do laminado de CFRP. Através dos resultados obtidos verificou-se uma melhoria do comportamento das lajes pré-esforçadas ao nível do estado limite último e de utilização

    Comportamento de lajes de betão armado reforçadas com laminados de CFRP pré-esforçados

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    O presente artigo resume o trabalho experimental relativo a ensaios à flexão até à rotura em 12 lajes de betão armado reforçadas com laminados de CFRP pré-esforçados. Foram estudados os seguintes parâmetros: dois sistemas de ancoragem (ancoragem metálica e ancoragem do gradiente de força), sistema passivo versus passivo, largura (50 mm e 80 mm) e espessura (1.2 mm e 1.4 mm) do laminado de CFRP e a influência da geometria da laje (2600 mm e 2200 mm de comprimento). No presente artigo o programa experimental é descrito e os principais resultados são apresentados e analisados

    Flexural behaviour of RC slabs strengthened with prestressed CFRP strips using different anchorage systems

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    The Externally Bonded Reinforcement (EBR) technique using Carbon Fiber-Reinforced Polymers (CFRP) has been commonly used to strengthen concrete structures in flexure. The use of prestressed CFRP material offers several advantages well-reported in the literature. Regardless of such as benefits, several studies on different topics are missing. The present work intends to contribute to the knowledge of two commercially available systems that differ on the type of anchorage: (i) the Mechanical Anchorage (MA), and (ii) the Gradient Anchorage (GA). For that purpose, an experimental program was carried out with twelve slabs monotonically tested under displacement control up to failure by using a four-point bending test configuration. The effect of type of anchorage system (MA and GA), prestrain level (0 and 0.4%), width (50 mm and 80 mm) and thickness (1.2 mm and 1.4 mm) of the CFRP laminate, and the surface preparation (grinded and sandblasted) on the flexural response were the main studied parameters. Better performance was observed for the slabs: (i) with prestressed laminates, (ii) for the MA system, and (iii) with sandblasted surface preparation.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the project FRPreDur - PTDC/ECM-EST/2424/2012. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: S&P Clever Reinforcement Iberica Lda, S&P Clever Reinforcement Company (Switzerland), Tecnipor - Gomes & Taveira Lda., Via lam - Industrias Metalurgicas e Metalomecanicas, Lda., Hilti Portugal-Produtos e Servicos, Lda. The first and second authors wish also to acknowledge the grants SFRH/BD/98309/2013 and SFRH/BD/94850/2013, respectively, provided by FCT

    Flexural behaviour of hybrid FRC-GFRP/PUR sandwich panels

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    The present work has been developed in the scope of the research project ‘‘Easyfloor – Development of composite sandwich panels for building floor rehabilitation”. This project aims at developing a hybrid sandwich panel, constituting an alternative construction system to conventional floor solutions, mainly for buildings rehabilitation. The developed hybrid sandwich panel is composed of a top face layer of steel fibre reinforced self-compacting concrete (FRC), a core of polyurethane (PUR) closed-cell foam and a bottom face sheet and lateral webs of glass fibre reinforced polymer (GFRP). The composite (GFRP/PUR) is manufactured by pultrusion, and its cross-section includes a sheet of GFRP between the FRC and PUR. After the production of the composite part, fresh FRC is poured onto the FRP component to materialize the top face of the panel. Full-scale tests on the developed sandwich panels have been carried out to characterize their flexural behaviour. The experimental programme included flexural tests i) on single supported panels, ii) on two panels side adhesively bonded and iii) on single panels with different connection solutions to walls. The present work includes a detailed description of the developed panels and of the experimental programme. It also presents and discusses the relevant results. The observed performance of the tested specimens is critically analysed.FCT - Fundação para a Ciência e a Tecnologia (SFRH/BSAB/150266/2019

    DROOd: desidratação de fruta e vegetais por ar seco

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    Apresenta-se um equipamento capaz de desidratar alimentos que poderá ser adquirido por pequenos agricultores. A proposta de um equipamento que consegue desidratar os produtos produzidos através de ar seco com uma potência equivalente à de um eletrodoméstico, 1,4 kW, tendo a capacidade de desidratar até 4 kg de frutas ou vegetais. Apresenta-se a simulação do funcionamento do equipamento a secar o equivalente a 23 tomates ou 24 bananas ou 21 laranjas simultaneamente distribuídos em 7 tabuleiros individuais, demorando 10, 8 e 9h, respetivamente, a serem desidratados.info:eu-repo/semantics/publishedVersio

    Prevalence of asymptomatic visceral occlusive disease in patients admitted for chronic lower limb ischemia: A cross-sectional study.

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    INTRODUCTION: Occlusive disease of the visceral vessels, when complicated, may lead to a high mortality rate. Current data regarding the co-prevalence of atherosclerotic disease of the lower limbs and visceral vessels is scarce. The aim of this study was to analyze the prevalence of splanchnic and renal visceral occlusive disease in patients admitted for chronic lower limb ischemia (CLLI). METHODS: A cross-sectional study was performed including 100 aleatory patients admitted for CLLI between 2015 and 2020, without previous or current history of mesenteric ischemia, and who were submitted to an abdominal computer tomography angiography (CTA) as part of the pre-operative work-up. The presence of splanchnic (celiac artery, superior and inferior mesenteric arteries) and renal atheromatous disease was defined as mild (30- 50% stenosis), moderate (50-70%) and severe (>70% or occlusion), measured by CTA. Outcomes analyzed included prevalence of splanchnic and renal visceral occlusive disease, evaluation of predictive factors for visceral occlusive disease and its relationship with the pattern of lower limb atherosclerotic disease. RESULTS: Mean age was 68.5 years old (SD: 9.7) and 77% were men. Admission diagnosis was incapacitating claudication (Rutherford stage 3) in 19%, and chronic lower limb threating ischemia (CLTI) in 81% (21% with stage 4 Rutherford and 60% with stage 5/6). Seventy-five percent presented aorto-iliac disease (AOID) and 97% presented infra-inguinal disease. Overall prevalence of visceral disease (mild, moderate or severe) was 65%. Severe disease was seen in at least one vessel in 60%. 34% of patients presented severe disease in only one visceral artery, 26% presented in ≥2 visceral vessels and 22% presented severe disease in all three splanchnic arteries. Regarding renal disease, 33% presented severe disease in at least one renal artery and 20% presented with bilateral disease. CLTI was significantly associated with a higher prevalence of severe stenosis in ≥2 splanchnic vessels, p=0.004. After logistic regression, we observed as predictive factor associated with severe disease in ≥2 splanchnic vessels the age, with an OR of 2.01 for every 10-year difference, p= 0.039; and AOID, OR: 14.6 (p=0.011). When analyzed the presence of at least one severe splanchnic vessel stenosis, AOID (OR 5.4, p=0.008) and coronary disease (OR:3.9, p=0.035) were predictive factors. Regarding renal disease, and association was found with age (OR of 3.90 for every 10-year difference, p<0.001); AOID (OR of 25.6, p=0.004) and carotid artery disease (OR: 9.24, p=0.005). CONCLUSION: Our study showed a high prevalence of multi-visceral and renal occlusive disease in patients admitted for chronic lower limb ischemia. We found an association between coronary and carotid disease with splanchnic and renal disease, respectively. Age was also associated with more severe stages of visceral and renal artery disease. More studies are needed to analyze the clinical impact of our findings regarding planning and follow-up for these patients.

    A ciência-cidadã ao serviço da mudança: o exemplo do projeto A Minha Praia

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    Vencedor da 1ª edição do Orçamento Participativo Portugal (2017), A Minha Praia é um projeto de monitorização ambiental que pretende sensibilizar para a conservação do meio marinho e estimular hábitos de consumo responsáveis, através de ações de ciência cidadã e civismo ambiental.SFRH/BGCT/135195/2017info:eu-repo/semantics/publishedVersio
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