A utilização da tela de aço como reforço de pavimentos asfálticos no combate ao trincamento por reflexão é uma alternativa utilizada desde 1980 em países europeus. Uma revisão da literatura a respeito de sua utilização na reabilitação de pavimentos asfálticos, mostra que, a sua utilização acaba diminuindo o aparecimento de trincas nas camadas de revestimento, agindo como uma barreira contra a sua propagação, oferece resistência ao cisalhamento especialmente sob elevadas tensões e ainda, melhora a resistência à fadiga contribuindo para a longevidade do pavimento. Entretanto, o potencial de sua utilização tem sido pouco investigado em rodovias brasileiras. Neste contexto, insere-se esta pesquisa com o objetivo de avaliar o efeito do reforço gerado pela inserção da tela em revestimentos asfálticos para o uso em pavimentos flexíveis, com o propósito de tornar as estruturas rodoviárias menos onerosas com consequente aumento da sua vida útil. Para isso, foi realizada uma pesquisa visando à análise do seu desempenho em um trecho experimental localizado na rodovia SP-354, no Estado de São Paulo entre as cidades de Campo Limpo Paulista e Jarinu, fundamentado nas melhores práticas internacionais, recorrendo à observação em campo e laboratório, análise por meio de ensaios de módulo de resiliência e cálculos por retroanálise para verificação do efeito da inserção da tela, ainda propondo, uma metodologia de dimensionamento estrutural de reforço de pavimentos asfálticos considerando a faixa de valores de módulo de resiliência integrados com a tela e o fator de deflexão (K) para cálculo de espessura de reforço. Conclui-se que esta técnica de reforço tem potencial para prolongar a vida útil de revestimentos asfálticos em pavimentos flexíveis, com benefícios também para o desempenho da camada na fase pós-trincamento. Foram obtidos modelos que permitem dimensionar o revestimento asfáltico com o propósito de avaliar o efeito da tela de aço na zona tracionada da camada. Por fim, foi verificada através de um estudo de viabilidade técnica/econômica que a incorporação da tela de aço em pavimentos flexíveis é uma alternativa eficaz e de adequada viabilidade técnica e econômica. / The use of the steel mesh as reinforcement of asphalt pavements to combat reflective cracks by reflection is an alternative used since 1980 in European countries. A review of the literature on the use of the steel mesh in the rehabilitation of asphalt pavements shows that its use prevents the appearance of cracks acting as a barrier against its propagation, offers resistance to shearing especially under high tensions and also improves the resistance to fatigue contributing to the longevity of the pavement. However, the potential if its use has been little investigated in Brazilian highways. In this context this project is to develop a new technology for road construction and rehabilitation. The idea is to use steel mesh reinforcement in asphalt roads in order to make road structures more cost effective by improving the lifetime of new constructed roads and by developing an optimal rehabilitation method for existing roads. For this, a research was performed aiming at the analysis of its performance in an experimental section located on the highway SP-354, in the State of São Paulo between the cities of Campo Limpo Paulista and Jarinu, based on the best international practices, using observation of its behavior in the field and laboratory, analysis by means of resilient modulus tests and calculations by backcalculation to verify the effect of the insertion of the screen, still proposing, a methodology of asphalt pavement design considering the range of integrated resilience module values with the screen and the structural deflection reduction factor (K) admissible for reinforcement projects. It was concluded that this reinforcing technique has potential for improvements crack propagation post-cracking behavior and permanent deformation in the asphalt concrete surfacing layer, with a ten fold increase on fatigue life to be expected. A model was developed that may be employed for pavement design modifying a model based on the use of conventional fatigue laws for the asphalt concrete, if the grid is positioned at the tensile zone of the surfacing layer. Finally, it was verified through a technical / economic study that the incorporation of the steel mesh in flexible pavements is an effective alternative and of adequate technical and economic viability.

A novel electrode was constructed and tested in a bio-battery. This configuration consisted of a composite electrode with immobilized bacteria (Escherichia coli K-12) in the anode and a composite electrode with immobilized Carbon Nanoparticles (CNP) and algae (Chlorella vulgaris/Scenedesmus sp.) suspended in the cathode. The composite electrode consisted of three parts: a 304L stainless steel mesh base, an electro-polymerized layer of pyrrole, and an electro-polymerized layer of methylene blue. The bacteria were immobilized on the anode electrode using a technique incorporating CNP and a Teflontm emulsion. The anode and cathode electrodes were tested separately in conjunction with chemical cathodes and anodes respectively. The composite electrode with immobilized bacteria was tested in a bioanode setup. The cathode chamber of the cell contained a potassium ferricyanide and buffer solution with a graphite electrode. Factors affecting electrode performance, such as Teflontm and carbon nanoparticle concentration, were investigated to find optimum values. The maximum power density generated by the composite electrode with immobilized bacteria and a chemical cathode was 378 mW/m2. This electrode configuration produced approximately 69% more power density and 53% more current density than composite electrodes with bacteria suspended in solution. Electrochemical Impedance Spectroscopy analysis determined that a significant portion of the bio-battery’s resistance to charge transfer occurred at the surface of the anode and this resistance was significantly lowered when using immobilized bacteria (51% lower than bio-batteries with suspended bacteria). Similarly, biocathodes containing composite electrodes coated with CNP were tested using two algae species, Chlorella vulgaris and Scenedesmus sp., suspended in solution. This electrode configuration was compared with composite electrode without CNP coating. The anode chamber contained potassium ferrocyanide solution with a graphite counter electrode. The composite electrode with CNP produced approximately 23% more current density than composite electrode without CNP. A complete bio-battery was designed using a composite electrode with immobilized bacteria anode and a CNP coated composite electrode with algae suspended in the cathode. EIS analysis showed that the resistance was higher in the biocathode than in the bioanode and a significant portion of the ohmic resistance was contributed by the membrane.

A utilização da tela de aço como reforço de pavimentos asfálticos no combate ao trincamento por reflexão é uma alternativa utilizada desde 1980 em países europeus. Uma revisão da literatura a respeito de sua utilização na reabilitação de pavimentos asfálticos, mostra que, a sua utilização acaba diminuindo o aparecimento de trincas nas camadas de revestimento, agindo como uma barreira contra a sua propagação, oferece resistência ao cisalhamento especialmente sob elevadas tensões e ainda, melhora a resistência à fadiga contribuindo para a longevidade do pavimento. Entretanto, o potencial de sua utilização tem sido pouco investigado em rodovias brasileiras. Neste contexto, insere-se esta pesquisa com o objetivo de avaliar o efeito do reforço gerado pela inserção da tela em revestimentos asfálticos para o uso em pavimentos flexíveis, com o propósito de tornar as estruturas rodoviárias menos onerosas com consequente aumento da sua vida útil. Para isso, foi realizada uma pesquisa visando à análise do seu desempenho em um trecho experimental localizado na rodovia SP-354, no Estado de São Paulo entre as cidades de Campo Limpo Paulista e Jarinu, fundamentado nas melhores práticas internacionais, recorrendo à observação em campo e laboratório, análise por meio de ensaios de módulo de resiliência e cálculos por retroanálise para verificação do efeito da inserção da tela, ainda propondo, uma metodologia de dimensionamento estrutural de reforço de pavimentos asfálticos considerando a faixa de valores de módulo de resiliência integrados com a tela e o fator de deflexão (K) para cálculo de espessura de reforço. Conclui-se que esta técnica de reforço tem potencial para prolongar a vida útil de revestimentos asfálticos em pavimentos flexíveis, com benefícios também para o desempenho da camada na fase pós-trincamento. Foram obtidos modelos que permitem dimensionar o revestimento asfáltico com o propósito de avaliar o efeito da tela de aço na zona tracionada da camada. Por fim, foi verificada através de um estudo de viabilidade técnica/econômica que a incorporação da tela de aço em pavimentos flexíveis é uma alternativa eficaz e de adequada viabilidade técnica e econômica. / The use of the steel mesh as reinforcement of asphalt pavements to combat reflective cracks by reflection is an alternative used since 1980 in European countries. A review of the literature on the use of the steel mesh in the rehabilitation of asphalt pavements shows that its use prevents the appearance of cracks acting as a barrier against its propagation, offers resistance to shearing especially under high tensions and also improves the resistance to fatigue contributing to the longevity of the pavement. However, the potential if its use has been little investigated in Brazilian highways. In this context this project is to develop a new technology for road construction and rehabilitation. The idea is to use steel mesh reinforcement in asphalt roads in order to make road structures more cost effective by improving the lifetime of new constructed roads and by developing an optimal rehabilitation method for existing roads. For this, a research was performed aiming at the analysis of its performance in an experimental section located on the highway SP-354, in the State of São Paulo between the cities of Campo Limpo Paulista and Jarinu, based on the best international practices, using observation of its behavior in the field and laboratory, analysis by means of resilient modulus tests and calculations by backcalculation to verify the effect of the insertion of the screen, still proposing, a methodology of asphalt pavement design considering the range of integrated resilience module values with the screen and the structural deflection reduction factor (K) admissible for reinforcement projects. It was concluded that this reinforcing technique has potential for improvements crack propagation post-cracking behavior and permanent deformation in the asphalt concrete surfacing layer, with a ten fold increase on fatigue life to be expected. A model was developed that may be employed for pavement design modifying a model based on the use of conventional fatigue laws for the asphalt concrete, if the grid is positioned at the tensile zone of the surfacing layer. Finally, it was verified through a technical / economic study that the incorporation of the steel mesh in flexible pavements is an effective alternative and of adequate technical and economic viability.

>Magister Scientiae - MSc / In recent times, the occurrence and presence of complex recalcitrant toxic contaminants in water and wastewater is increasing and consequently contributes to the non-availability of clean and safe drinking water. Water treatment is complex, time demanding and energy intensive due to the physico-chemical structural complexity and diversity of the pollutants. Non-availability of good drinking water has negatively affected human health and the ecosystem. Over the years, numerous conventional treatment techniques were used to degrade and remove these pollutants, but investigations indicated that some of the pollutants are not susceptible to conventional treatment. Advanced oxidation technology, among which heterogeneous photocatalysis (involving the use of a semiconductor) has emerged as one of the more promising techniques to remediate contaminated water. Titanium dioxide (TiO2) semiconductor photocatalysis is considered to be a good option due to its cost effectiveness, chemical and thermal stability, and inertness in the area of wastewater reclamation and re-use. However the post separation of the titania particles poses a threat to the wastewater remediation. Hence there is a need to develop a supported high surface area photocatalyst that will resolve the post separation challenge. This present study aimed to prepare high surface area TiO2 anatase nanocrystals supported on a stainless steel mesh. These new composite materials were used to remove methylene blue (MB) from aqueous solutions. The supporting procedure involved the thermal decomposition of a sol gel solution coated upon stainless steel mesh. The nanocrystalline anatase phase was formed by thermal decomposition on a stainless steel mesh coated with 8 % PAN/DMF/TiO2 sol gel formation calcined at varying temperatures of 300 °C, 400 °C, 500 °C and 600 °C. The heating rate of 50 °C/min and independent holding time of 1 h, 2 h, 3 h and 4 h were applied to find the optimum supporting conditions. The synthesised TiO2 nanocomposites materials were characterised using the following analytical techniques: XRD, HRSEM, EDS, HRTEM, SAED, FTIR and UV-Vis absorption spectroscopy materials were characterised, and the results indicate that synthesised TiO2 nanocrystals were in the anatase form, polycrystalline in nature, and contained additional carbon-carbon bonds from the polymer used during preparation with TiO2 particle sizes range from 13.6 nm to 2285 nm.

This study examines whether woven metal mesh is an appropriate option for usage in beds and what material the mesh should consist of to best be suited for the purpose. The woven steel mesh’s construction was based on a reference model that consists of cross-linked rods and wires. Since the aim of the project was to reach a conclusion of the mesh’s usability in beds, different parameters were examined and taken into consideration. These parameters were the durability of the mesh when carrying human weight, acoustic properties to minimize chatter when lying on the mesh and rolling properties. The durability was examined using COMSOL multiphysics. Acoustics were studied through a literature review and rolling properties were calculated using measurements on the reference model. A material investigation was done in the database software CES EduPack. It was found that steel, stainless steel and aluminum fulfilled the requirements set on durability. Stainless steel was considered too expensive and steel too heavy. Using aluminum halves the weight of the mesh in comparison to steel but doubles the price, in this case however the weight was considered to be a parameter of greater importance overriding price.

As lajes dos tabuleiros de pontes de concreto armado, sejam elas maciças ou executadas com pré-lajes, são elementos estruturais suscetíveis à fadiga, devido às ações a que são submetidas. As pré-lajes, pelo fato de serem resultantes da junção de dois concretos diferentes, torna-se ainda mais suscetível à fadiga. Este trabalho apresenta estudos, ensaios e análise de resultados a respeito do comportamento à fadiga das lajes de pontes de concreto, sejam as maciças ou as executadas com pré-laje, armadas com barras ou telas soldadas. Foram realizados ensaios de fadiga de barra ao ar CA50 f10 mm isoladas e em telas para a construção da Curva de Wöhler nas condições brasileiras. Além disso, foram ensaiadas 23 lajes de concreto, sendo 6 lajes maciças e 17 executadas com prélajes, montadas com diversas configurações de armadura, submetidas a ensaios estáticos e dinâmicos. As configurações de armaduras adotadas nas lajes da pesquisa foram baseadas nas utilizadas com freqüência neste tipo de elemento das pontes, escala ½. Um dos principais motivos que levaram ao desenvolvimento desta pesquisa de caráter experimental foi a escassez de dados sobre o comportamento de lajes armadas com barras ou telas soldadas de fabricação brasileira, submetidas a ações cíclicas. Outro motivo foi a carência de estudos a respeito da iteração prélaje x capa. Foi verificado que não houve ruptura nessa região da estrutura devido aos carregamentos cíclicos aplicados no meio do vão. Ficou evidenciado também que as soldas das telas afetam sua resistência à fadiga. / Concrete bridge slabs, massive or pre-slabs, are structural elements susceptible to fatigue, due to loading applied to them. Pre-slabs, result of two different concretes, become even more susceptible to fatigue. This research presents the studies, tests and analysis of the results about the behavior of concrete bridge massive slabs or pre-slabs reinforced with steel bars and welded steel meshes due to fatigue loading. Axial testing in air of CA50 f10 mm in continuous bars and steel meshes were made in order to build the Wöhler Curve to the Brazilian conditions. Besides that, tests were made in 23 concrete slabs, 6 massive slabs and 17 preslabs, with several reinforcements arrangements, submitted to static and dynamic loading. The reinforcement configurations adopted in the slabs were based on the commonly used in these bridge elements in scale ½. One of main reasons that lead this experimental research development was the scarcity of data about the behavior of concrete slabs reinforced with rebars and welded mesh made in Brazil, submitted to cycle loading. Another reason was the lack of studies about the iteration between pre-slab and concrete cover. It was verified that no rupture was found in this region of the structure due to midspan cycle loading. The welding process caused loss of fatigue resistance.

As lajes dos tabuleiros de pontes de concreto armado, sejam elas maciças ou executadas com pré-lajes, são elementos estruturais suscetíveis à fadiga, devido às ações a que são submetidas. As pré-lajes, pelo fato de serem resultantes da junção de dois concretos diferentes, torna-se ainda mais suscetível à fadiga. Este trabalho apresenta estudos, ensaios e análise de resultados a respeito do comportamento à fadiga das lajes de pontes de concreto, sejam as maciças ou as executadas com pré-laje, armadas com barras ou telas soldadas. Foram realizados ensaios de fadiga de barra ao ar CA50 f10 mm isoladas e em telas para a construção da Curva de Wöhler nas condições brasileiras. Além disso, foram ensaiadas 23 lajes de concreto, sendo 6 lajes maciças e 17 executadas com prélajes, montadas com diversas configurações de armadura, submetidas a ensaios estáticos e dinâmicos. As configurações de armaduras adotadas nas lajes da pesquisa foram baseadas nas utilizadas com freqüência neste tipo de elemento das pontes, escala ½. Um dos principais motivos que levaram ao desenvolvimento desta pesquisa de caráter experimental foi a escassez de dados sobre o comportamento de lajes armadas com barras ou telas soldadas de fabricação brasileira, submetidas a ações cíclicas. Outro motivo foi a carência de estudos a respeito da iteração prélaje x capa. Foi verificado que não houve ruptura nessa região da estrutura devido aos carregamentos cíclicos aplicados no meio do vão. Ficou evidenciado também que as soldas das telas afetam sua resistência à fadiga. / Concrete bridge slabs, massive or pre-slabs, are structural elements susceptible to fatigue, due to loading applied to them. Pre-slabs, result of two different concretes, become even more susceptible to fatigue. This research presents the studies, tests and analysis of the results about the behavior of concrete bridge massive slabs or pre-slabs reinforced with steel bars and welded steel meshes due to fatigue loading. Axial testing in air of CA50 f10 mm in continuous bars and steel meshes were made in order to build the Wöhler Curve to the Brazilian conditions. Besides that, tests were made in 23 concrete slabs, 6 massive slabs and 17 preslabs, with several reinforcements arrangements, submitted to static and dynamic loading. The reinforcement configurations adopted in the slabs were based on the commonly used in these bridge elements in scale ½. One of main reasons that lead this experimental research development was the scarcity of data about the behavior of concrete slabs reinforced with rebars and welded mesh made in Brazil, submitted to cycle loading. Another reason was the lack of studies about the iteration between pre-slab and concrete cover. It was verified that no rupture was found in this region of the structure due to midspan cycle loading. The welding process caused loss of fatigue resistance.

Tato Diplomová práce se zabývá vlivem vyztužení na mechanické vlastnosti materiálu pro přípravu snímatelných náhrad. Pro testování byly použity tři sady vzorků: PMMA pryskyřice, PMMA pryskyřice s Dentapreg Mesh výztuží a PMMA pryskyřice vyztužena zesilující síťkou z nerezové oceli.Pro měření chování vzorků při statickém a dynamickém namáhání byl použit třibodový ohybový test a Charpy rázové kladivo. Viskoelastické vlastnostzi byly měřeny dynamicko-mechanickou analýzou (DMA). Skenovací elektronová mikroskopie (SEM) byla použita k charakterizaci lomových ploch. Během statického namáhání vzorků výztuž nehraje důležitou roli v porovnání s nevyztuženou pryskyřicí. Nicméně byl pozorován opačný trend při dymanickém namáhání, kde efekt výzruže rostl v řadě PMMA pryskyřice – síťka z nerezové oceli – Dentapreg Mesh.