Adição de vermiculita expandida mícron em pastas de baixa densidade para cimentação de poços de petróleo

The northeastern region of Brazil has a large number of wells producing oil using a method of secondary recovery steam injection, since the oil produced in this region is essentially viscous. This recovery method puts the cement / coating on thermal cycling, due to the difference in coefficient of thermal expansion between cement and metal coating causes the appearance of cracks at this interface, allowing the passage of the annular fluid, which is associated with serious risk socioeconomic and environmental. In view of these cracks, a correction operation is required, resulting in more costs and temporary halt of production of the well. Alternatively, the oil industry has developed technology for adding new materials in cement pastes, oil well, providing high ductility and low density in order to withstand the thermo-mechanical loads generated by the injection of water vapor. In this context, vermiculite, a clay mineral found in abundance in Brazil has been applied in its expanded form in the construction industry for the manufacture of lightweight concrete with excellent insulation and noise due to its high melting point and the presence of air in their layers lamellar. Therefore, the vermiculite is used for the purpose of providing low-density cement paste and withstand high temperatures caused by steam injection. Thus, the present study compared the default folder containing cement and water with the folders with 6%, 8% and 10% vermiculite micron conducting tests of free water, rheology and compressive strength where it obtained the concentration of 8 % with the best results. Subsequently, the selected concentration, was compared with the results recommended by the API standard tests of filtered and stability. And finally, analyzed the results from tests of specific gravity and time of thickening. Before the study we were able to make a folder with a low density that can be used in cementing oil well in order to withstand the thermo-mechanical loads generated by steam injection

Estudos e propriedades mecânicas de um novo tipo de bloco cerâmico híbrido para edificações em alvenarias estruturais

This dissertation presents a hybrid ceramic block the use of which reside in the buildings executed with walls. Initially, we conducted a survey on the requirements and / or norms prevailing in Brazil about structural ceramic blocks, making use of the experiences in other countries. This work seeks new materials and / or products in order to maintain or increase the compressive strength of the ceramic blocks, without neglecting the other properties. Then was collected materials (clay and crushed powder) and an approach on the characterization, through fluorescence, Mineralogy, vitrification curve and characterization of these materials used in the manufacture of the blocks by Ray Diffraction "X" and SEM. Subsequently it was made, numbered and measured dimensions of about 150 bodies of the test piece (hybrid ceramic blocks in small sizes) with varying percentages of 0%, 5%, 10% and 15% substitution of crushed clay powder. After sintering of the bodies of the test piece at temperatures of 900oC, 1000oC 1100oC and with a heating rate of 5oC/minuto and level of 1 hour, the samples were submitted to the tests (compressive strength and water absorption) and calculated their retractions, which were subsequently carried out the analysis of the results according to the criteria and parameters required by Brazilian legislation and standards in force

Processamento e caracterização de compósitos Poli(METACRILATO DE METILA)/Sílica (PMMA/SiO2)

Currently the search for new materials with properties suitable for specific applications has increased the number of researches that aim to address market needs. The poly (methyl methacrylate) (PMMA) is one of the most important polymers of the family of polyacrylates and polymethacrylates, especially for its unique optical properties and weathering resistance, and exceptional hardness and gloss. The development of polymer composites by the addition of inorganic fillers to the PMMA matrix increases the potential use of this polymer in various fields of application. The most commonly used inorganic fillers are particles of silica (SiO2), modified clays, graphite and carbon nanotubes. The main objective of this work is the development of PMMA/SiO2 composites at different concentrations of SiO2, for new applications as engineering plastics. The composites were produced by extrusion of tubular film, and obtained via solution for application to commercial PMMA plates, and also by injection molding, for improved the abrasion and scratch resistance of PMMA without compromising transparency. The effects of the addition of silica particles in the polymer matrix properties were evaluated by the maximum tensile strength, hardness, abrasion and scratch resistance, in addition to preliminary characterization by torque rheometry and melt flow rate. The results indicated that it is possible to use silica particles in a PMMA matrix, and a higher silica concentration produced an increase of the abrasion and scratch resistance, hardness, and reduced tensile strength

Influência do método de síntese e caracterização de pós compósitos de NiO- Ce1-xEuxO2-δ para anodos catalíticos de células a combustível

Fuel cells are electrochemical devices that convert chemical energy into electricity. Due to the development of new materials, fuel cells are emerging as generating clean energy generator. Among the types of fuel cells, categorized according to the electrode type, the solid oxide fuel cells (SOFC) stand out due to be the only device entirely made of solid particles. Beyond that, their operation temperature is relatively high (between 500 and 1000 °C), allowing them to operate with high efficiency. Another aspect that promotes the use of SOFC over other cells is their ability to operate with different fuels. The CeO2 based materials doped with rare earth (TR+3) may be used as alternatives to traditional NiO-YSZ anodes as they have higher ionic conductivity and smaller ohmic losses compared to YSZ, and can operate at lower temperatures (500-800°C). In the composition of the anode, the concentration of NiO, acting as a catalyst in YSZ provides high electrical conductivity and high electrochemical activity of reactions, providing internal reform in the cell. In this work compounds of NiO - Ce1-xEuxO2-δ (x = 0.1, 0.2 and 0.3) were synthesized from polymeric precursor, Pechini, method of combustion and also by microwave-assisted hydrothermal method. The materials were characterized by the techniques of TG, TPR, XRD and FEG-SEM. The refinement of data obtained by X-ray diffraction showed that all powders of NiO - Cex-1EuxO2-δ crystallized in a cubic phase with fluorite structure, and also the presence of Ni. Through the characterizations can be proved that all routes of preparation used were effective for producing ceramics with characteristics suitable for application as SOFC anodes, but the microwave-assisted hydrothermal method showed a significant reduction in the average grain size and improved control of the compositions of the phases

Raman Spectroscopy and DFT calculations for the Electronic Structure Characterization of Conjugated Polymers

In the last three decades, there has been a broad academic and industrial interest in conjugated polymers as semiconducting materials for organic electronics. Their applications in polymer light-emitting diodes (PLEDs), polymer solar cells (PSCs), and organic field-effect transistors (OFETs) offer opportunities for the resolution of energy issues as well as the development of display and information technologies1. Conjugated polymers provide several advantages including low cost, light weight, good flexibility, as well as solubility which make them readily processed and easily printed, removing the conventional photolithography for patterning2. A large library of polymer semiconductors have been synthesized and investigated with different building blocks, such as acenes or thiophene and derivatives, which have been employed to design new materials according to individual demands for specific applications. To design ideal conjugated polymers for specific applications, some general principles should be taken into account, including (i) side chains (ii) molecular weights, (iii) band gap and HOMO and LUMO energy levels, and (iv) suited morphology.3-6 The aim of this study is to elucidate the impact that substitution exerts on the molecular and electronic structure of π-conjugated polymers with outstanding performances in organic electronic devices. Different configurations of the π-conjugated backbones are analyzed: (i) donor-acceptor configuration, (ii) 1D lineal or 2D branched conjugated backbones, and (iii) encapsulated polymers (see Figure 1). Our combined vibrational spectroscopy and DFT study shows that small changes in the substitution pattern and in the molecular configuration have a strong impact on the electronic characteristics of these polymers. We hope this study can advance useful structure-property relationships of conjugated polymers and guide the design of new materials for organic electronic applications.

Efeito da adição do poli(etileno acrilato de metila) (ema) e da fibra de linter de algodão nas propriedades do poli(tereftalato de etileno) reciclado (petrec)

The development of new materials to fill the demand of technological advances is a challenge for many researchers around the world. Strategies such as making blends and composites are promising alternatives to produce materials with different properties from those found in conventional polymers. The objective of this study is to evaluate the effect of adding the copolymer poly(ethylene methyl acrylate) (EMA) and cotton linter fibers (LB) on the properties of recycled poly(ethylene terephthalate) (PETrec) by the development of PETrec/EMA blend and PETrec/EMA/LB blend composite. In order to improve the properties of these materials were added as compatibilizers: Ethylene - methyl acrylate - glycidyl methacrylate terpolymer (EMA-GMA) and maleic anhydride grafted polyethylene (PE-g-MA). The samples were produced using a single screw extruder and then injection molded. The obtained materials were characterized by thermogravimetry (TG), melt flow index (MFI) mensurements, torque rheometry, pycnometry to determinate the density, tensile testing and scanning electron microscopy (SEM). The rheological results showed that the addition of the EMA copolymer increased the viscosity of the blend and LB reduces the viscosity of the blend composite. SEM analysis of the binary blend showed poor interfacial adhesion between the PETrec matrix and the EMA dispersed phase, as well as the blend composite of PETrec/EMA/LB also observed low adhesion with the LB fiber. The tensile tests showed that the increase of EMA percentage decreased the tensile strength and the Young s modulus, also lower EMA percentage samples had increased the elongation at break. The blend composite showed an increase in the tensile strength and in the Young`s modulus, and a decrease in the elongation at break. The blend formulations with lower EMA percentages showed better mechanical properties that agree with the particle size analysis which showed that these formulations presented a smaller diameter of the dispersed phase. The blend composite mechanical tests showed that this material is stronger and stiffer than the blend PETrec/EMA, whose properties have been reduced due to the presence of EMA rubbery phase. The use of EMA-GMA was effective in reducing the particle size of the EMA dispersed phase in the PETrec/EMA blend and PE-g-MA showed evidences of reaction with LB and physical mixture with the EMA

Retratamento endodôntico cirúrgico

Introdução: O presente trabalho tem como tema Microcirurgia Endodôntica sendo esta um tipo de Retratamento Endodôntico Cirúrgico (RTEC). Este tipo de procedimento está indicado em casos de insucesso prévio no Tratamento Endodôntico Não Cirúrgico (TENC). Embora atualmente os índices de sucesso do TENC sejam elevados, existem ainda alguns casos, que não atingem os resultados desejados mesmo realizando corretamente todas as etapas do tratamento. Quando assim é, há necessidade de abordar o sistema de canais radiculares por outra via: recorrer à cirurgia endodôntica e à obturação retrógrada. Objetivos: Esta dissertação tem como objetivo principal abordar uma técnica de Retratamento Endodôntico Cirúrgico: a Microcirurgia Endodôntica. Procedeu-se a uma revisão bibliográfica, analisando literatura que versa o tema, a evolução da técnica, o protocolo cirúrgico em toda a sua extensão, a sua utilidade e aplicabilidade na prática clínica. Materiais e métodos: Na execução desta revisão bibliográfica, os motores de pesquisa on-line utilizados foram os seguintes: b-On, Pubmed, Scielo, Science Direct e Google Académico. Os critérios de inclusão limitaram o uso de artigos publicados entre 2000 e 2016 e nos idiomas de português, inglês e espanhol. Os critérios de exclusão rejeitaram artigos dos quais o teor não teria relevância para a concretização do trabalho e artigos fora dos limites temporais. Conclusão: Na literatura científica, quando a técnica Microcirurgica é comparada com a técnica convencional de RTEC mostra uma taxa de sucesso de excelência e que maioritariamente, os autores defendem que esta deverá ser usada apenas como retratamento, e não isoladamente ou como primeira abordagem terapêutica. Nas últimas décadas, o crescente desenvolvimento científico e tecnológico da cirurgia endodôntica leva à introdução da microcirurgia graças ao recurso da magnificação e iluminação, instrumentos adaptados à nova realidade da cirurgia endodôntica, novos equipamentos e novos materiais associados à retrobturação. É de salientar que este processo cirúrgico é menos invasivo para o paciente e que se obtém um aumento das taxas de sucesso.

Materiais electrocrómicos e mecaelectroquímicos: contextualização e experimentação na disciplina de química do 12º ano

Durante os últimos 1O anos, em particular, tem-se assistido à descoberta e desenvolvimento de materiais com propriedades únicas e potencialmente úteis em vários domínios da Ciência e Tecnologia. Quer seja na área das Ciências Biomédicas e do Ambiente, na área das Novas Tecnologias de Informação e Comunicação ou nas Novas Tecnologias relacionadas com sistemas de Conversão e Armazenamento de Energia Eléctrica, encontram-se inúmeros exemplos de Novos Materiais com propriedades muito interessantes, e cujas aplicações inovadoras podem revolucionar o nosso Mundo. O presente trabalho é uma proposta de contextualização e experimentação do tema "Materiais Electrocrómicos e Mecaelectroquímicos" no Programa de Química de 12° Ano, nomeadamente na terceira Unidade - Plásticos, Vidros e Novos Materiais. Neste, é apresentada uma sub-unidade que possa integrar a unidade referida. Faz-se especial referência às aplicações dos polímeros condutores, que pela sua inovação e actualidade tomam a leccionação do tema mais apelativa, interessante e facilitadora de uma literacia científica. São apresentadas experiências laboratoriais demonstrativas e elucidativas do tema em questão. Como forma de apoiar a leccionação do referido tema, é apresentada a proposta de uma animação gráfica animada em Power Point. ABSTRACT: During the past 1O years, in particular, it has witnessed to the discovery and development of materials with unique properties and potentially useful in various fields of Science and Technology. There are numerous examples of new materials in different areas, such as Biomedical, Energy and Environmental Sciences and New information and Communication Technologies, with very interesting properties, and whose innovative applications can have an outstanding impact in our world. This dissertation is a proposal of contextualization and experimentation of theme "Electrochromic Materials and Electrochemical Artificial Muscles" in the Program of Chemistry, in 12th year, particularly in the third unit - Plastics, Glass and New Materials. lt will present a sub-unit that can integrate the unit above. The definitions and some applications of the Electrochromic Materials and Electrochemical Artificial Muscles are showed. Demonstrative and illustrative laboratory experiments of the theme are proposed. ln order to support the teaching of that subject, it is presented an animated graphical presentation in Power Point.

O engenheiro Adriano Monteiro e a utilização do ferro na reconversão e refuncionalização de espaços em Évora: o caso do Palácio D. Manuel e dos Paços do Concelho

Resumo A partir da segunda metade do século XIX e XX assistiu-se à introdução de novos materiais, como o ferro fundido, o aço e o vidro, na remodelação ou construção de edifícios que procuravam dar resposta às novas necessidades de gestão urbana e de criação de espaços de lazer e sociabilidade. Nestas intervenções, que ficaram marcadas pela arquitectura do ferro, os engenheiros, grupo profissional detentor de competências técnicas que os habilitavam a trabalhar com estes materiais, tiveram um papel determinante. Na cidade de Évora a ligação entre a utilização de novos materiais e os engenheiros, é visível no papel que o Engenheiro Adriano Monteiro teve na reconversão do Palácio D. Manuel e na remodelação do edifício dos Paços do Concelho. Palavras-chave: Engenheiro, Arquitectura do Ferro, Évora, Palácio D. Manuel, Paços do Concelho Abstract From the second half of the nineteenth century onwards, there was the introduction of new materials, such as cast iron, steel and glass, in the remodeling or in the construction of buildings that sought to satisfy the new needs of urban management and the creation of leisure spaces and sociability. In these interventions that were marked by the iron architecture, the engineers, a professional group with technical skills that enabled them to work with these materials, played a decisive role. In the city of Évora this link between the utilization of new materials and engineers, is visible in the role that engineer Adriano Monteiro had in the conversion of the D. Manuel Palace and in the remodeling of the Town Hall building. Keywords: Engineers, Iron Architecture, Évora, D. Manuel Palace, City Hall

Crystal engineering of co-crystals and host-guest systems for environmentally friendly applications: sunscreens stabilization, pollutant sequestering and herbicide reformulation.

Solid state engineered materials have proven to be useful and suitable tools in the quest of new materials. In this thesis different crystalline compounds were synthesized to provide more sustainable products for different applications, as in cosmetics or in agrochemistry, to propose pollutants removal strategy or to obtain materials for electrocatalysis. Therefore, the research projects presented here can be divided into three main topics: (i) sustainable preparation of solid materials of widely used active ingredients aimed at the reduction of their occurrence in the natural environment. The systems studied in this section are cyclodextrins host-guest compounds, obtained via mechanochemical and slurry synthesis. The first chemicals studied are sunscreens inclusion complexes, that proved to have enhanced photostability and desired photoprotection. The same synthetic methods were applied to obtain inclusion complexes of bentazon, a herbicide often found to leach in groundwaters. The resulting products showed to have desired water solubility properties. The same herbicide was also adsorbed on amorphous calcium phosphate nanoparticles, to obtain a biocompatible formulation of this agrochemical. This herbicide could benefit by the adsorption on nanoparticles for what concerns its kinetic release in different media as well as its photostability. (ii) Sustainable synthesis of co-crystals based on polycyclic aromatic hydrocarbons, for the proposal of a sequestering method with a resulting material with enhanced properties. The co-crystallization via mechanochemical means proved that these pollutants can be sequestered via simple solvent-free synthesis and the obtained materials present better photochemical properties when compared to the starting co-formers. (iii) Crystallization from mild solvents of nanosized materials useful for the application in electrocatalysis. The study of compounds based on nickel and cobalt metal ions resulted in the obtainment of 2D and 1D coordination polymers. Moreover, solid solutions were obtained. These crystals showed layered structures and, according to preliminary results, they can be exfoliated.

Strategies for lowering the environmental impact of different electrochemical energy storage system

The continuous growth of global population brings an exponential increase on energy consumption and greenhouse gas emission in the atmosphere contributing to the increase of the planet temperature. Therefore, it is mandatory to adopt renewable energy production systems like photovoltaic or wind power: unfortunately, the main limit of these technologies is the natural intermittence of the energy sources that limits their applicability. The key enabling technology for a widespread usage of clean power sources are electrochemical energy storage systems, most commonly known as batteries. Batteries will enable the storage of energy during overproduction period and the release during low production period stabilizing the power outcome, allowing the connection to the main grid and increasing the applicability of renewable energy sources. Despite the high number of benefits that the widespread use of batteries will bring, starting from the reduction of CO2 emitted in the atmosphere, it is necessary also to take care of the environmental impact of processes and materials used for the production of electrochemical storage systems. In addition, there are many different battery systems, with different chemistries and designs that require specific strategies. Nowadays, the most part of the materials and chemicals used for battery production are toxic for humans and the environment. For this reason, this Ph.D. thesis addresses the challenging scope of lowering the environmental impact of manufacturing processes of different electrochemical energy storage systems using natural derived or low carbon footprint materials while increasing the performances with respect to commercial devices. The activities carried out during my Ph.D. cover a high number of different electrochemical storage systems involving a wide range of electrochemical processes from capacitive to faradic. New materials, different production processes and new battery design, all in view of sustainability and low environmental impact, increased the innovative and challenging aspects of this work.

Synthesis, characterization and potential applications of novel metal-organic frameworks

​The research work described in this thesis concerns the synthesis, characterization, and applications of two kinds of metal-organic frameworks (MOFs), Copper based MOF (Cu-MOF) and zirconium based MOF (Zr-MOF) functionalized with new linkers. ​The common thread of this research project can be summarized in three work phases: ​first, the synthesis and characterization of new organic linkers is described, followed by the presentation of the different optimization conditions for the MOFs synthesis. ​Second, the new materials were fully characterized using several complementary techniques, such as infrared (ATR-FTIR) and Raman spectroscopy, X-ray powder diffraction spectroscopy (PXRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS) as well as thermal and surface area measurements. ​Final, to obtain a complete work the possible environmental applications of the new materials were explored.

Multi-functional electrocatalysts for CO2 reduction reaction: towards the modulation of selectivity

The electrocatalytic reduction of CO2 (CO2RR) is a captivating strategy for the conversion of CO2 into fuels, to realize a carbon neutral circular economy. In the recent years, research has focused on the development of new materials and technology capable of capturing and converting CO2 into useful products. The main problem of CO2RR is given by its poor selectivity, which can lead to the formation of numerous reaction products, to the detriment of efficiencies. For this reason, the design of new electrocatalysts that selectively and efficiently reduce CO2 is a fundamental step for the future exploitation of this technology. Here we present a new class of electrocatalysts, designed with a modular approach, namely, deriving from the combination of different building blocks in a single nanostructure. With this approach it is possible to obtain materials with an innovative design and new functionalities, where the interconnections between the various components are essential to obtain a highly selective and efficient reduction of CO2, thus opening up new possibilities in the design of optimized electrocatalytic materials. By combining the unique physic-chemical properties of carbon nanostructures (CNS) with nanocrystalline metal oxides (MO), we were able to modulate the selectivity of CO2RR, with the production of formic acid and syngas at low overpotentials. The CNS have not only the task of stabilizing the MO nanoparticles, but the creation of an optimal interface between two nanostructures is able to improve the catalytic activity of the active phase of the material. While the presence of oxygen atoms in the MO creates defects that accelerate the reaction kinetics and stabilize certain reaction intermediates, selecting the reaction pathway. Finally, a part was dedicated to the study of the experimental parameters influencing the CO2RR, with the aim of improving the experimental setup in order to obtain commercial catalytic performances.

Polyhydroxyalkanoates production from salted food waste using mixed microbial cultures.

Plastic is an essential asset for the modern lifestyle, given its superiority as a material from the points of view of cost, processability and functional properties. However, plastic-related environmental pollution has become nowadays a very significant problem that can no longer be overlooked. For this reason, in recent decades, the research for new materials that could replace fossil fuel-based plastics has been focused on biopolymers with similar physicochemical properties to fossil fuel-based plastics, such as Polyhydroxyalkanoates (PHA). PHAs are a family of biodegradable polyesters synthesized by many microorganisms as carbon and energy reserves. PHA appears as a good candidate to substitute conventional petroleum-based plastics since it has similar properties, but with the advantage of being biobased and biodegradable, and has a wide range of applications (e.g., packaging). However, the PHA production cost is almost four times higher (€5/kg) than conventional plastic manufacturing. The PHA production by mixed microbial cultures (MMC) allows to reduce production costs as it does not require aseptic conditions and it enables the use of inexpensive by-products or waste streams as these cultures are more amenable to deal with complex feedstocks. Saline wastewaters (WWs), generated by several industries such as seafood, leather and dairy, are often rich in organic compounds and, due to a strong salt inhibition, the biological treatments are inefficient, and their disposal is expensive. These saline WWs are a potential feedstock for PHA production, as they are an inexpensive raw material. Moreover, saline WWs could allow the utilization of seawater in the process as dilution and cleaning agent, further decreasing the operational costs and the environmental burden of the process. The main goal of the current project is to assess and optimize the PHA production from a mixture of food waste and brine wastewater from the fishery industry by MMC.

Polymerization of isatin towards polymers for anion exchange membranes and gas separation applications

In a world where the problem of energy resources, pollution and all aspects related to these issues become more and more dominant, a greater commitment is needed in the search for solutions. The goal of this project is to make a contribution to the research and development of new materials to reduce the environmental impact in some fields. First of all, we tried to synthesize and prepare an isatin-based membrane which has the potential for use in separating industrial gases. Furthermore, ion exchange membranes, specifically hydroxide exchange membranes (HEMs) derived from the same product can be developed for fuel cells (HEMFC) applications. These materials are essential for energy conversion and storage. The most difficult challenge is to guarantee their thermal stability and stability in corrosive environments such as alkali without losing efficiency. In recent years the poly- hydroxyalkylation catalysed with superacids, e.g. TFSA, has become increasingly studied. This reaction is exploited for the synthesis of the compounds of this thesis. After a preliminary optimization of the reaction conditions it was concluded that due to the rigidity and excessive reactivity of the system, it was not possible to obtain the isatin-based membrane to evaluate the gas separation properties. The synthesis of precursor materials for HEMs was successful by using 1-(4-bromobutyl)indoline-2,3-dione (BID) instead of isatin. A characterization of the obtained polymers was carried out using NMR, TGA and DSC analyses, and subsequently the membranes were functionalized with different ammonium-based cations. Unfortunately, this last step was not successful due to the appearance of side reactions. Future studies on the mechanism and kinetics of the reaction solve this obstacle.