Corrosion of steel reinforcement in concrete structures poses a risk reduction of durability and ability to perform the required function of structures for which they were designed.The objective of this work was to study the effectiveness of a new type of corrosion inhibitor with different concentrations of the active substance and its comparison with commercial products. The corrosion inhibitors were part of a comprehensive system repair materials from Betosan s.r.o. and using the electrical measurements was studied their effect in reducing corrosion activity caused by aggressive chloride environments.

This master’s thesis is focused on measurement of electrical contact resistance. The beginning of the thesis is devoted to the introduction of the electrical contact resistance and electrical parameters of journal bearings. Next part of the thesis deals with engineering design of test rig. In order to verify functional measurement principle, the test rig based on engineering design has been made. In the end of the thesis the measuring devices and the measuring process is described. The measurement results from the test rig are presented.

Orientador: Michelli Leali Costa / Resumo: Dentre os setores de aplicações comerciais de materiais compósitos avançados, destaca-se o setor aeroespacial com larga aplicação desses materiais. Entre as técnicas de união aplicadas aos compósitos termoplásticos está a soldagem com grandes vantagens em relação aos outros processos de uniões tais como, redução de custo, agilidade de processamento, redução de elementos acumuladores de tensão, preparações mais simplórias das superfícies a serem soldadas. Mesmo com essas vantagens e, embora o processo já seja utilizado nos setores industriais, a soldagem de compósitos tem como desafio a melhoria de sua resistência, a aplicação do processo para reparos ou processamentos em campo, além da necessidade de avaliação dos efeitos das condições climáticas em juntas soldadas, as quais podem estar submetidas quando em operação em uma aeronave, por exemplo. Mediante a isso, esse trabalho visa produzir e estudar juntas soldadas por resistência elétrica e por tocha acetilênica em compósito PEI/fibra de vidro. Os compósitos obtidos foram submetidos ao condicionamento higrotérmico seguido de ensaios mecânicos de LSS (Lap Shear Strength) e ENF (End-Notched Flexure). O mecanismo de fratura das juntas soldadas foi avaliado por microscopia. A partir das análises e dos resultados obtidos, foi observado que os valores de resistência ao cisalhamento em modo II dos compósitos soldados por resistência elétrica (3270,9 J/m²) são similares aos descritos na literatura para os compósitos PEI/fibra de vid... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Among the commercial application sectors of advanced composite materials, the aerospace sector with wide application of these materials stands out. Among the joining techniques applied to thermoplastic composites is welding with great advantages over other joining processes such as cost reduction, processing agility, reduction of stress accumulators, little or no preparation required of the surface to be processed. Even with these advantages, and although the process is already used in the industrial sectors, composite welding has the challenge of improving its resistance, the application of the process for field repairs or processing, and the need to evaluate the effects of weather conditions. welded joints, which may be subjected when operating in an aircraft, for example. Therefore, this work aims to produce and study joints welded by electric resistance and acetylene torch in PEI / fiberglass composite. The composites obtained were subjected to hygrothermal conditioning followed by mechanical tests of LSS (Lap Shear Strength) and ENF (End-Notched Flexure). The fracture mechanism of the welded joints was evaluated by microscopy. From the analyzes and results obtained, it was observed that the shear strength values in mode II of the composites welded by electric resistance (3270.9 J / m²) are similar to those described in the literature for PEI / fiberglass composites. However, for the composites welded by the oxyacetylene process, a reduction of approximately 20% in the va... (Complete abstract click electronic access below) / Mestre

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Introduction Oral delivery of proteins faces numerous challenges due to their enzymatic susceptibility and instability in the gastrointestinal tract. In recent years, the polyelectrolyte complexes have been explored for their ability to complex protein and protect them against chemical and enzymatic degradation. However, most of the conventional binary polyelectrolyte complexes (PECs) are formed by polycations which are associated with toxicity and non-specific bio-interactions. The aim of this thesis was to prepare a series of ternary polyelectrolyte complexes (APECs) by introduction of a polyanion in the binary complexes to alleviate the aforementioned limitations. Method Eight non-insulin loaded ternary complexes (NIL APECs) were spontaneously formed upon mixing a polycation [polyallylamine (PAH), palmitoyl grafted-PAH (Pa2.5), dimethylamino-1-naphthalenesulfonyl grafted-PAH (Da10) or quaternised palmitoyl-PAH (QPa2.5)] with a polyanion [dextran sulphate (DS) or polyacrylic acid (PAA)] at 2:1 ratio, in the presence of ZnSO4 (4μM). A model protein i.e., insulin was added to a polycation, prior to addition of a polyanion and ZnSO4 to form eight insulin loaded (IL) APECs. PECs were used as a control to compare APECs. The complexes were characterised by dynamic light scattering (DLS) and transmission electron microscope (TEM). In vitro stability of the complexes was investigated at pH (1.2-7.4), temperature (25˚C, 37˚C and 45˚C) and ionic strength (NaCl-68mM, 103mM and 145mM). Insulin complexation efficiency was assessed by using bovine insulin ELISA assay kit. The in vitro cytotoxicity was investigated on CaCo2 and J774 cells by MTT (3-4,5 dimethyl thialzol2,5 diphenyl tetrazolium bromide) assay. All complexes were evaluated for their haemocompatibility by using haemolysis assay, oxidative stress by reactive oxygen species (ROS) assay and immunotoxicity by in vitro and in vivo cytokine generation assay. The potential of the uptake of complexes across CaCo2 cells was determined by flow cytometry and fluorescent microscopy. The underlying mechanism of transport of complexes was determined by TEER measurement, assessment of FITC-Dextran and insulin transport across CaCo2 cells. 15 Results NIL QPa2.5 APECs (except IL QPa2.5-DS) exhibited larger hydrodynamic sizes (228-468nm) than all other APECs, due to the presence of bulky quaternary ammonium moieties. QPa2.5 APECs exhibited lower insulin association efficiency (≤40%) than other APECs (≥55%) due to a competition between the polyanion and insulin for QPa2.5 leading to reduced association of insulin in the complexes. DS based APECs generally offered higher insulin association efficiency (≥75%) than PAA based APECs (≤55%) due to higher molecular weight (6-10kDa) of DS. In comparison to other complexes, Pa2.5 PECs and APECs were more stable at varying temperature, ionic strength and pH due to the presence of long palmitoyl alkyl chain (C16) which reduced the chain flexibility and provided stronger hydrophobic association. The cytotoxicity of polycations on CaCo2 and J774 cells is rated as PAH>Da10=Pa2.5>QPa2.5. The introduction of PAA in Pa2.5 and Da10 brought most significant improvement in IC50 i.e., 14 fold and 16 fold respectively on CaCo2 cells; 9.3 fold and 3.73 fold respectively on J774 cells. In comparison to other complexes, Da10 (8mgml-1) induced higher haemolytic activity (~37%) due to a higher hydrophobic load of 10 percent mole grafting of dansyl pendants. The entire range of APECs displayed ≤12% ROS generation by the CaCo2 cells. The degree of in vitro TNFα production (QPa2.5≥Da10≥Pa2.5=PAH) and in vitro IL-6 generation (QPa2.5≥Pa2.5=PAH≥Da10) by J774 cells established an inverse relationship of cytotoxicity with the cytokine generation. Similar to MTT data, the introduction of PAA in APECs brought more significant reduction in in vitro cytokine secretion than DS based APECs. Pa2.5-PAA brought the most significant reduction in both in vitro and in vivo cytokine generation. All the formulations were able to significantly reduce original TEER, however did not demonstrate appreciable paracellular permeation of a hydrophilic macromolecular tracer of paracellular transport i.e., FITC Dextran. The uptake study revealed internalisation of APECs predominantly by a transcellular route. Transcellular uptake of IL QPa2.5 (≤73%), IL QPa2.5-DS (67%) was higher than their NIL counterparts, whereas the uptake of NIL Pa2.5 (≤89%), NIL Pa2.5-PAA (42%) was higher than their IL counterparts. Conclusion In essence, amphiphilic APECs have shown polyanion dependent ability to reduce polycation associated toxicity and they are able to facilitate transcellular uptake of insulin across CaCo2 cells.

Submitted by ISABELA ATILIO null (isabelaatilio@hotmail.com) on 2017-10-31T16:58:11Z No. of bitstreams: 1 Dissertação Final - Isabela Atilio.pdf: 12968588 bytes, checksum: 24d1b58efcf37a8ffc0d9ed1afc4d7d4 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-11-10T19:48:34Z (GMT) No. of bitstreams: 1 atilio_i_me_guara.pdf: 12968588 bytes, checksum: 24d1b58efcf37a8ffc0d9ed1afc4d7d4 (MD5) / Made available in DSpace on 2017-11-10T19:48:34Z (GMT). No. of bitstreams: 1 atilio_i_me_guara.pdf: 12968588 bytes, checksum: 24d1b58efcf37a8ffc0d9ed1afc4d7d4 (MD5) Previous issue date: 2017-09-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O aumento da demanda por petróleo e seus derivados tem instigado o desenvolvimento de materiais para dutos com elevadas tenacidade à fratura e resistência mecânica, como os aços de alta resistência e baixa liga (ARBL) pertencentes às classes API. Aliada à utilização destes aços, a aplicação do processo de soldagem por resistência elétrica de alta frequência (HF/ERW) tem conquistado maior interesse no setor. Entretanto, defeitos nas juntas soldadas constituem uma das principais causas de falhas em dutos, principalmente quando associados às condições externas de operação, o que tem sido motivo para estudos relacionados à integridade estrutural destes tubos. O objetivo deste trabalho foi estudar a tenacidade à fratura de um tubo de aço API 5L X70 soldado pelo processo HF/ERW, a partir de dados obtidos com ensaios CTOD de espécimes de flexão por três pontos, tipo SE(B) “gull wing”. A metodologia proposta envolveu ensaios de CTOD a variadas temperaturas, incluindo a região de transição dúctil-frágil, a fim de avaliar a integridade estrutural do material em condições críticas de operação. Os ensaios foram realizados com base nas normas ASTM E1820 e BS7448, e consistiram na utilização de corpos de prova retirados diretamente da parede do tubo, com posterior planificação. De forma geral, as amostras de material base apresentaram uma boa tenacidade à fratura em todas as temperaturas de ensaio, o que não aconteceu com as amostras de material de solda, que apresentaram baixa tenacidade. Os resultados de tenacidade obtidos mostraram que a metodologia empregada para o estudo da integridade estrutural por meio de ensaios CTOD com amostras extraídas diretamente da parede do tubo, com posterior planificação, mostrou-se adequada. Embora as normas ASTM E1820 e BS7448 adotem diferentes parâmetros para a determinação do valor de CTOD, observou-se que os valores de CTOD foram bem próximos. / The increasing demand for oil and its products has driven the development of materials for ducts with high fracture toughness and high mechanical strength, such as high strength low alloy (HSLA) steels, appertaining to the API classes. In addition to the use of these steels, the application of the high frequency resistance welding process (HF/ERW) has gained greater interest in the sector. However, defects in the welded joints are one of the most causes of failures in pipelines, especially when they are associated with external operating conditions, which has been the reason for studies related to the structural integrity of these tubes. The aim of this work was to study the fracture toughness of an API 5L X70 steel tube welded by the HF/ERW process, from data obtained with CTOD tests bending specimens by three points, type SE (B) gull wing. The proposed methodology involved CTOD tests at various temperatures, including the ductile-brittle transition region, in order to assess the structural integrity of the material under critical operating conditions. The tests were performed based on the ASTM E1820 and BS7448 standards, and consisted of the use of specimens taken directly from the wall of the tube, with subsequent planning. In general, the base material samples showed good fracture toughness at all test temperatures, which did not occur with the samples of welded material, which presented low toughness. The toughness results obtained showed that the methodology used for the study of structural integrity by means of the CTOD tests with samples drawn directly from the wall of the tube, with subsequent planning, was adequate. Although the ASTM E1820 and BS7448 standards adopt different parameters for the determination of the CTOD value, it was observed that the CTOD values were very close.

Dans les applications automobiles et dans d'autres domaines (énergie, aviation, etc), le nombre d'appareils électroniques a augmenté de façon significative au cours des dernières décennies. La sécurité des systèmes et des personnes repose sur la qualité de connecteurs électriques. Toutefois, soumis à des vibrations (moteur de la voiture, de l'environnement) des microdéplacements sont induits à l’interface. La problématique du contact électrique est principalement liée à l'altération de la conduction de faible courant (5mA) dans les interfaces soumises à des contraintes mécaniques de glissement répétitifs engendrant un phénomène bien connu de fretting par l’usure. La sollicitation de fretting usure apparait comme un processus de dégradation très pénalisant. Outre la détérioration des surfaces, ce processus conduit à une augmentation de la résistance électrique des contacts et à une possible perte du signal électrique. Ceci est particulièrement le cas pour les connecteurs bas niveau très sensibles aux fluctuations de la résistance électrique. Pour remédier à cela, les acteurs de la connectique développent de nouveaux dépôts pour limiter l’utilisation de dépôts nobles tels que l’or. Les objectifs de cette thèse sont d’établir une "table d’utilisation" des revêtements en fonction de sollicitations précises et de mettre en place une méthodologie dans le choix des dépôts en vue d’optimiser la durée de vie des connecteurs. L’étude aborde différents aspects tels que les influences des conditions de chargements mécaniques, des épaisseurs de dépôts, du type de dépôt (noble, non noble, dopé), de l’amplitude de débattement (micro-déplacement et grand déplacement) et la formalisation de l’endurance électrique (loi puissance et approche énergétique). / In automotive applications and in other areas (energy, aviation, etc.), the number of electronic devices has increased significantly in recent last decades. Systems and people securities are based on the quality of electrical connectors. However, submitted to vibrations (car engine, environment) micro-displacements are induced at the interface. The problem of electrical contact is mainly due to the impairment of low current conduction (5mA) in interfaces subjected to repetitive sliding displacement generating a well-known fretting wear phenomenon. Fretting wear solicitation appears as a process of very detrimental degradation. Besides surface deterioration, this process leads an increase of the electrical contact resistance and a possible loss of the electrical signal. This is particularly the case of the low level connectors which are very sensitive to electrical contact fluctuations. To remedy, connections actors develop new deposits to limit the use of noble ones such as gold. The objectives of this thesis are to establish a "table of use" coatings based on specific solicitations and define a methodology for the selection of deposits to optimize the lifetime connectors. The study covers different aspects such as the mechanical loading conditions influence, the thickness deposits influence, the type of deposit (noble, non-noble, doped), the displacement amplitude (microdisplacement and large displacement) and the electrical endurance formalization (energetic approach and power law).

Ordinary concrete is the most commonly used building material, but nowadays the requirements for low energy consumption, durability of structures together with their easy diagnostics as well as ecological production raises. This thesis deals with cement and aluminosilicate composites with content of conductive fillers, which allows to monitor the change in electrical properties, most commonly electrical resistance in dependence on mechanical stress. In the experimental part of the thesis, test beams were produced based on alkali-activated slag with content of carbon nanotubes, graphite powder, carbon black and carbon fibre. The beams were subjected to flexural loading in a three-point bending configuration and the shift in electrical resistance was monitored.