Caracterização do comportamento da ligação entre betões de distinta classe de resistência

Comunicação apresentada no Encontro Nacional Betão Estrutural 2004, Porto, Portugal, 17 - 19 Nov. 2004.O incremento do momento flector resistente que a técnica de reforço baseada na fixação de laminados de CFRP no betão de recobrimento de estruturas laminares de betão armado, por vezes, fica limitado pela extensão máxima de compressão aplicável ao betão. Nestes casos, a conjugação deste sistema de reforço com a aplicação de uma camada de compressão de betão reforçado com fibras de aço (BRFA) permite aumentar significativamente a resistência à flexão deste tipo de estruturas. Este trabalho é dedicado ao estudo da ligação entre camada de BRFA e o betão da estrutura a reforçar.Fundação para a Ciência e Tecnologia - SFRH/BD/11232/2002. “Companhia Geral de Cal e Cimento S.A. (SECIL)”. Sika S.A. “Central do Pego”. “Pedreiras Bezerras”. Bekaert NV. “Bettor MBT Portugal Produtos Químicos para Construção S.A.”

Drug-induced disseminated intravascular coagulation: a pharmacovigilance study on World Health Organization’s database

Background: Disseminated intravascular coagulation (DIC) occurs in several clinical conditions, including drug therapy. We aim to investigate the association between the administration of several drug classes and the onset of DIC by using the reports of Adverse Drug Reactions (ADR) collected in Vigibase, the World Health Organization (WHO) database of ADR. Methods: We collected reports of drug-related DIC from 1968 to September 2015, classified in Vigibase according to the MedDRA (Medical Dictionary for Regulatory Activities) term “Disseminated intravascular coagulation”. A disproportionality analysis using Reporting Odds Ratio (ROR) with 95% Confidence Interval (CI95%) was performed. Results: Overall, 4653 reports of drug-associated DIC were retrieved and the 75.9% of them was serious according to WHO seriousness criteria. DIC was significantly (ROR > 1, lower limit of CI95% > 1) associated with 88 drugs, mainly antineoplastic agents, antithrombotic agents and antibacterials for systemic use. Among of the most frequently reported individual drugs we found dabigatran (94 reports) ROR = 1.34 (CI95% 1.08–1.67), oxaliplatin and bevacizumab both with 75 reports and ROR = 1.77 (1.38–2.27) and 2.02 (1.57–2.61), respectively. Conclusion: A substantial number of drugs, widely used in the clinical practice, may be associated with the potential occurrence of DIC. For many of these drugs, the ADR is not acknowledged in the corresponding Summary of Product Characteristics. The high number of drugs involved underlines the importance of evaluate this condition such as an ADR that might occur during drug therapy

On bonding repairing steel fibre reinforced concrete to hardened concrete

In the last years an emerging repair and strengthening technique for concrete slabs has been used, consisting of applying a thin layer of steel fibre reinforced concrete (SFRC) onto the existent concrete slab. The performance of the structural system depends on the bonding behaviour between old and new concretes. Adhesives based on epoxy resins currently make this liaison. The prices of these adhesives are quite different depending, mainly, on the percentage of pure resin that they include. In the present paper, three commercial adhesive compounds of distinct prices and properties were selected to bond concrete base and repairing SFRC overlay. The bond behaviour was assessed from pull-off tests and the influence of the strength class of concrete base and repairing SFRC was analysed. Finally, the performance of the adhesives was evaluated, considering both the bond strength and their prices.Fundação para a Ciência e a Tecnologia (FCT) - PhD grant SFRH/BD/11232/2002

Sistema híbrido em materiais compósitos para reforço de lajes de betão armado

O desempenho em termos de aumento da resistência à flexão da técnica de reforço que combina laminados de CFRP à tracção com camada de compressão em betão reforçado com fibras de aço (BRFA), foi avaliado experimentalmente, efectuando-se ensaios em faixas de lajes maciças sem reforço (controlo), reforçadas apenas com laminados de CFRP, e duplamente reforçadas com laminados de CFRP e camada de BRFA. Os resultados obtidos permitem concluir que esta estratégia de reforço é eficaz, tanto para o estado limite de serviço (ELS) quanto para o estado limite último (ELU)

Efficient strengthening technique to increase the flexural resistance of existing RC slabs: NSM CFRP laminates and compressive thin bonded SFRC overlay

Technical report 09-DEC/E-0

Growth response and body composition of sharpsnout sea bream (Diplodus puntazzo) fed a high energy diet with different protein levels.

A study was undertaken to determine the effect of a high energy diet with two different protein levels on growth, feed efficiency and whole body composition of sharpsnout sea bream (Diplodus puntazzo). Two isoenergetic diets (24.1-24.7 MJ Kg-1 dry weight) with two different protein levels (46.7 and 52.5 % dry weight) were fed to satiety to duplicate groups of 300 fish (initial body weight 27.7 \ub1 0.2 g) for 94 days. At the end of the experiment, the fish fed 52.5 % protein showed a statistically higher (P < 0.05) daily intake rate (DIR) of feed. Feed conversion rate (FCR) was similar among groups. Whole body composition was similar among treatments while the high enrgy level of the diets significantly modified lipid and moisture content in comparison with fish at the beginning of the experiment. Protein efficiency ratio (PER), gross protein efficiency (GPE) of fish fed 46.7 % protein diet were statistically higher than those for the other diet. It may be concluded that the diet with a lower protein level has given better protein utilization and a protein sparing effect but tended to result in reduced weight gain and feed intake, when compared with diet containing higher protein levels

Concrete slabs strips reinforced with epoxy-bonded carbon laminates into slits

A promising strengthening strategy, using carbon fiber reinforced polymer (CFRP) materials, consists in applying CFRP laminate strips into pre-cut slits opened in the concrete cover of the elements to strengthen. Since both faces of the laminate are bonded to concrete by epoxy adhesive, the maximum attainable strain in the CFRP at the failure of the strengthened element is higher than when the CFRP is externally bonded. This strengthening technique is designated by Near Surface Mounted and has been successfully used to increase the flexural and the shear resistance of concrete and masonry structures. In the present work, the effectiveness of this technique to increase the service and ultimate load carrying capacity of reinforced concrete slabs is assessed by an experimental program. A numerical strategy was developed to predict the load-deflection relationship of this type of elements. The results are presented and analyzed, and the performance of the numerical model is appraised.Fundação para a Ciência e a Tecnologia (FCT) - PhD grant number SFRH/BD/11232/2002.S&P® Reinforcement.Degussa Construction Chemicals Portugal SA.Companhia Geral de Cal e Cimento SA (SECIL).Pedreiras Bezerras

Composite materials for the structural strengthening of reinforced masonry shells

Since the 1950s, the Uruguayan engineer Eladio Dieste designed curved lightweight masonry shells of impressive span width, complex shape and high attractiveness. This structural system is composed of a top mortar cover, a layer of clay bricks, mortar joints, and steel reinforcement. For the permanent loads, this structural system has been working satisfactory, in spite of rebar corrosion being detected in some shells. However, if submitted to an earthquake of considerable magnitude, damage can be significant, and its rupture can even occur. In the present paper, an effective strengthening technique, using carbon fibre reinforced polymer (CFRP) materials, was developed to significantly increase the ultimate load of damaged reinforced masonry shell structures. This strengthening system is composed by strips of wet lay-up CFRP sheet and prefabricated CFRP laminates. The sheet strips are bonded, with epoxy resin, to the top cracked concrete surface of the shell to increase its flexural resistance for the negative bending moments, while laminates are fixed, with epoxy adhesive, to the bottom of the reinforced concrete joints to increase the shell flexural resistance for the positive bending moments. This strengthening system was applied to a damaged shell, having resulted a significant increase in the service load and an increase of about 76% in the ultimate load. A monitoring system was installed to evaluate the applied force, the deflection in critical sections and the strains in the composite materials and in the steel reinforcement. The experimental research is described and the main results are presented and discussed

Evaluation of the safety profile of rotavirus vaccines: a pharmacovigilance analysis on American and European data

Rotaviruses (RVs) are the most common cause of severe diarrheal disease. To date two rotavirus oral vaccines are licensed: Rotarix and Rotateq. Our aim was to contribute to the post-marketing evaluation of these vaccines safety profile. We collected all RV vaccines-related reports of Adverse Events Following Immunization (AEFI) in US Vaccine Adverse Events Reporting System (VAERS) and VigiBase between January 2007 and December 2017. A disproportionality analysis using Reporting Odds Ratio (ROR) was performed. A total of 17,750 reports in VAERS and 6,358 in VigiBase were retrieved. In VAERS, 86.2% of the reports concerned RotaTeq, whereas in VigiBase 67.7% of them involved Rotarix. Across the databases, diarrhea (1,672 events in VAERS, 1,961 in VigiBase) and vomiting (1,746 in VAERS, 1,508 in VigiBase) were the most reported AEFIs. Noteworthy, the RV vaccines-intussusception pair showed a ROR greater than 20 in both databases. Some new potential safety signals emerged such as fontanelle bulging, hypotonic-hyporesponsive episode, livedo reticularis, and opisthotonus. Overall, our data show that most of the reported AEFIs are listed in the Summary of Product Characteristics (SPCs). However, there remains the need to investigate the potential safety signals arose from this analysis, in order to complete the description of the AEFIs

Efficient strengthening technique to increase the flexural resistance of existing RC slabs

Composite materials are being used with notable effectiveness to increase and upgrade the flexural load carrying capacity of reinforced concrete (RC) members. Near-Surface Mounted (NSM) is one of the most promising strengthening techniques, based on the use of carbon fiber-reinforced polymer (CFRP) laminates. According to NSM, the laminates are fixed with epoxy based adhesive into slits opened into the concrete cover on the tension face of the elements to strength. Laboratory tests have shown that the NSM technique is an adequate strengthening strategy to increase the flexural resistance of RC slabs. However, in RC slabs of low concrete strength, the increase of the flexural resistance that NSM can provide is limited by the maximum allowable compressive strain in the compressed part of the slab, in order to avoid concrete crushing. This restriction reduces the effectiveness of the strengthening, thus limiting the use of the NSM technique. A new thin layer of concrete bonded to the existing concrete at the compressed region is suitable to overcome this limitation. Volumetric contraction due to shrinkage and thermal effects can induce uncontrolled cracking in the concrete of this thin layer. Adding steel fibers to concrete (Steel Fiber Reinforced Concrete - SFRC), the post cracking residual stress can be increased in order to prevent the formation of uncontrolled crack patterns. In the present work, the combined strengthening strategy, a SFRC overlay and NSM CFRP laminates, was applied to significantly increase the flexural resistance of existing RC slabs. Experimental results of four-point bending tests, carried out in unstrengthened and strengthened concrete slab strips, are presented and analyzed