Obtenção e caracterização de um compósito polimérico de matriz poliéster e reforço/carga de tecido plano de algodão

He was obtained and studied the feasibility of using TPA (Tissue Cotton Plan) screen type, for bagging, with a weight of 207.9 g / m2 in a composite of orthophthalic crystal polyester resin matrix. The process for obtaining the composite was tested against the maximum number of layers that could be used without compromising the processability and manufacturing of CPs in compression mold. Five configurations / formulations were selected and tested at 1, 4, 8, 10 and 12 layers of cotton tissue - TPA. TPA was not subjected to chemical treatment, only by passing a mechanical washing process. The composite in its various configurations / formulations was characterized to determine its physical properties. The properties of the composite were higher viability resistance to bending, approaching the matrix and impact resistance, superiority in relation to the polyester resin. Another property that has shown good result compared to other composite has water absorption. Analyzing all the properties set the settings / formulations with higher viability were TA8 and TA10, by combining good processability and higher mechanical strength, with lower loss compared to polyester resin matrix. The composite showed lower mechanical behavior of the resin matrix for all the formulations studied except the impact resistance. The SEM showed a good adhesion between the layers of TPA and polyester resin matrix, without the presence of micro voids in the matrix confirming the efficient manufacturing process of the samples for characterization. The composite proposed proved to be viable for the fabrication of structures with low requests from mechanical stresses, and as demonstrated for the manufacture of solar and wind prototypes, and packaging, shelving, decorative items, crafts and shelves, with good visual appearance.

Obtenção e caracterização de um compósito de matriz polimérica com carga de resíduos vegetal proveniente do sabugo de milho

The feasibility of using the corn cob to obtain a polymer matrix composite was studied. To obtain the bran, corncob passed the drying process in a solar dryer, and was subsequently triturated in forage and to obtain the different particle sizes, by sieving. Three different grain sizes were used: fine particles (FP) size between 0,10 and 2mm; sized particles (PM) with sizes between 2,10 and 3,35 mm; large particles (PG) sizes between 3,45 and 4,10 mm. Using 20% of residue relative to the resin, the test samples were constructed for characterization of the composite, taking into account thermal and mechanical parameters. The main advantage of the proposed composite is that it has a low density, below the relative resin, about 1.06 kg / m³ for the PG. The composite showed a mechanical behavior less than of the resin to the grain sizes and for all formulations studied. Showed better results for the bending, reaching 25.3 MPa for the PG. The composite also showed be feasible for thermal applications, with thermal conductivity less than 0.21 W / m, ranking as insulation. In terms of homogeneity of the mixture, the most viable grain size is the PF, which also showed improved aesthetics and better processability. This composite can be used to make structures that do not require significant mechanical strength, such as tables, chairs, planks, and solar and wind prototypes, such as ovens and cookers and turbines blades.

Obtenção e caracterização de um compósito de matriz polimérica com carga de resíduos vegetal proveniente do sabugo de milho

The feasibility of using the corn cob to obtain a polymer matrix composite was studied. To obtain the bran, corncob passed the drying process in a solar dryer, and was subsequently triturated in forage and to obtain the different particle sizes, by sieving. Three different grain sizes were used: fine particles (FP) size between 0,10 and 2mm; sized particles (PM) with sizes between 2,10 and 3,35 mm; large particles (PG) sizes between 3,45 and 4,10 mm. Using 20% of residue relative to the resin, the test samples were constructed for characterization of the composite, taking into account thermal and mechanical parameters. The main advantage of the proposed composite is that it has a low density, below the relative resin, about 1.06 kg / m³ for the PG. The composite showed a mechanical behavior less than of the resin to the grain sizes and for all formulations studied. Showed better results for the bending, reaching 25.3 MPa for the PG. The composite also showed be feasible for thermal applications, with thermal conductivity less than 0.21 W / m, ranking as insulation. In terms of homogeneity of the mixture, the most viable grain size is the PF, which also showed improved aesthetics and better processability. This composite can be used to make structures that do not require significant mechanical strength, such as tables, chairs, planks, and solar and wind prototypes, such as ovens and cookers and turbines blades.

Método híbrido para projeto de superfícies seletivas em frequência

This thesis presents a hybrid technique of frequency selective surfaces project (FSS) on a isotropic dielectric layer, considering various geometries for the elements of the unit cell. Specifically, the hybrid technique uses the equivalent circuit method in conjunction with genetic algorithm, aiming at the synthesis of structures with response single-band and dual-band. The equivalent circuit method allows you to model the structure by using an equivalent circuit and also obtaining circuits for different geometries. From the obtaining of the parameters of these circuits, you can get the transmission and reflection characteristics of patterned structures. For the optimization of patterned structures, according to the desired frequency response, Matlab™ optimization tool named optimtool proved to be easy to use, allowing you to explore important results on the optimization analysis. In this thesis, numeric and experimental results are presented for the different characteristics of the analyzed geometries. For this, it was determined a technique to obtain the parameter N, which is based on genetic algorithms and differential geometry, to obtain the algebraic rational models that determine values of N more accurate, facilitating new projects of FSS with these geometries. The optimal results of N are grouped according to the occupancy factor of the cell and the thickness of the dielectric, for modeling of the structures by means of rational algebraic equations. Furthermore, for the proposed hybrid model was developed a fitness function for the purpose of calculating the error occurred in the definitions of FSS bandwidths with transmission features single band and dual band. This thesis deals with the construction of prototypes of FSS with frequency settings and band widths obtained with the use of this function. The FSS were initially reviewed through simulations performed with the commercial software Ansoft Designer ™, followed by simulation with the equivalent circuit method for obtaining a value of N in order to converge the resonance frequency and the bandwidth of the FSS analyzed, then the results obtained were compared. The methodology applied is validated with the construction and measurement of prototypes with different geometries of the cells of the arrays of FSS.

Método híbrido para projeto de superfícies seletivas em frequência

This thesis presents a hybrid technique of frequency selective surfaces project (FSS) on a isotropic dielectric layer, considering various geometries for the elements of the unit cell. Specifically, the hybrid technique uses the equivalent circuit method in conjunction with genetic algorithm, aiming at the synthesis of structures with response single-band and dual-band. The equivalent circuit method allows you to model the structure by using an equivalent circuit and also obtaining circuits for different geometries. From the obtaining of the parameters of these circuits, you can get the transmission and reflection characteristics of patterned structures. For the optimization of patterned structures, according to the desired frequency response, Matlab™ optimization tool named optimtool proved to be easy to use, allowing you to explore important results on the optimization analysis. In this thesis, numeric and experimental results are presented for the different characteristics of the analyzed geometries. For this, it was determined a technique to obtain the parameter N, which is based on genetic algorithms and differential geometry, to obtain the algebraic rational models that determine values of N more accurate, facilitating new projects of FSS with these geometries. The optimal results of N are grouped according to the occupancy factor of the cell and the thickness of the dielectric, for modeling of the structures by means of rational algebraic equations. Furthermore, for the proposed hybrid model was developed a fitness function for the purpose of calculating the error occurred in the definitions of FSS bandwidths with transmission features single band and dual band. This thesis deals with the construction of prototypes of FSS with frequency settings and band widths obtained with the use of this function. The FSS were initially reviewed through simulations performed with the commercial software Ansoft Designer ™, followed by simulation with the equivalent circuit method for obtaining a value of N in order to converge the resonance frequency and the bandwidth of the FSS analyzed, then the results obtained were compared. The methodology applied is validated with the construction and measurement of prototypes with different geometries of the cells of the arrays of FSS.

Obtenção, caracterização e utilização de um compósito com matriz de resina poliéster e carga de fibras de sisal

The constant search for sustainable alternatives has earned great effort of researchers in research and obtaining new materials, encouraging the rise of eco-friendly productive development and providing simple and practical solutions to economic profitability. In this sense, the use of materials derived from natural renewable sources, vegetables, has great potential applicability to sustainable development. As alternative materials plant fibers can be applied to production of a range of composite materials easing the use of materials derived from non-renewable this thesis were sisal mats used for achieving a composite matrix having as one orthophthalic polyester resin. The webs were subjected to surface treatment in boiling water for 15 minutes. The webs of sisal fibers used were, respectively, 5%, 10% and 15% of the composite weight. The composite was obtained and characterized mechanically and thermally to the chosen formulations. several plates of the composite to obtain the body of evidence for the characterization tests complying with the relevant rules were made. The obtained composites showed strength tensile and bending lower than the array, so it can be used where are required low load requests. The most significant result of the composite studied given to the impact energy absorption, far superior to the matrix used. Other properties were highlighted in oil absorption, and density. It proved the feasibility of obtaining the composite for the three formulations studied C5, C10 and C15 being the most feasible to C10. To demonstrate the feasibility of using composite were made a wall clock, a bench, a chair and a shelf, low mechanical stress structures. It was concluded that the sisal rugs exercised the load function in the composite.

Obtenção, caracterização e utilização de um compósito com matriz de resina poliéster e carga de fibras de sisal

The constant search for sustainable alternatives has earned great effort of researchers in research and obtaining new materials, encouraging the rise of eco-friendly productive development and providing simple and practical solutions to economic profitability. In this sense, the use of materials derived from natural renewable sources, vegetables, has great potential applicability to sustainable development. As alternative materials plant fibers can be applied to production of a range of composite materials easing the use of materials derived from non-renewable this thesis were sisal mats used for achieving a composite matrix having as one orthophthalic polyester resin. The webs were subjected to surface treatment in boiling water for 15 minutes. The webs of sisal fibers used were, respectively, 5%, 10% and 15% of the composite weight. The composite was obtained and characterized mechanically and thermally to the chosen formulations. several plates of the composite to obtain the body of evidence for the characterization tests complying with the relevant rules were made. The obtained composites showed strength tensile and bending lower than the array, so it can be used where are required low load requests. The most significant result of the composite studied given to the impact energy absorption, far superior to the matrix used. Other properties were highlighted in oil absorption, and density. It proved the feasibility of obtaining the composite for the three formulations studied C5, C10 and C15 being the most feasible to C10. To demonstrate the feasibility of using composite were made a wall clock, a bench, a chair and a shelf, low mechanical stress structures. It was concluded that the sisal rugs exercised the load function in the composite.

Obtenção e caracterização de um compósito de matriz polimérica com carga de bucha vegetal luffa cylindrica

Composite materials arise from the need for lighter materials and with bigger mechanical and thermal resistance. The difficulties of discard, recycling or reuse are currently environmental concerns and, therefore, they are study object of much researches. In this perspective the feasibility of using loofahs (Luffa Cylindrica) for obtainment of a polymeric matrix composite was studied. Six formulations, with 4, 5 and 6 treated layers and untreated, were tested. The loofahs were treated in boiling water to remove lignins, waxes and impurities present in the fibers. After that, they were dried in a direct exposure solar dryer. For the characterization of the composite, thermal (thermal conductivity, thermal capacity, thermal diffusivity and thermal resistivity), mechanical (tensile and bending resistance) and physicochemical (SEM, XRD, density, absorption and degradation) properties were determined. The proposed composite has as advantage the low fiber density, which is around 0.66 g/cm³ (almost half of the polyester resin matrix), resulting in an average composite density of around 1.17g/cm³, 6.0 % lower in relation to the matrix. The treatment carried out in the loofahs increased the mechanical strength of the composite and decreased the humidity absorption. The composite showed lower mechanical behavior than the matrix for all the formulations. The composite also demonstrated itself to be feasible for thermal applications, with a value of thermal conductivity of less than 0.159 W/m.K, ranking it as a good thermal insulator. For all formulations/settings a low adherence between fibers and matrix occurred, with the presence of cracks, showing the fragility due to low impregnation of the fiber by the matrix. This composite can be used to manufacture structures that do not require significant mechanical strength, such as solar prototypes, as ovens and stoves.

Obtenção e caracterização de um compósito de matriz polimérica com carga de bucha vegetal luffa cylindrica

Composite materials arise from the need for lighter materials and with bigger mechanical and thermal resistance. The difficulties of discard, recycling or reuse are currently environmental concerns and, therefore, they are study object of much researches. In this perspective the feasibility of using loofahs (Luffa Cylindrica) for obtainment of a polymeric matrix composite was studied. Six formulations, with 4, 5 and 6 treated layers and untreated, were tested. The loofahs were treated in boiling water to remove lignins, waxes and impurities present in the fibers. After that, they were dried in a direct exposure solar dryer. For the characterization of the composite, thermal (thermal conductivity, thermal capacity, thermal diffusivity and thermal resistivity), mechanical (tensile and bending resistance) and physicochemical (SEM, XRD, density, absorption and degradation) properties were determined. The proposed composite has as advantage the low fiber density, which is around 0.66 g/cm³ (almost half of the polyester resin matrix), resulting in an average composite density of around 1.17g/cm³, 6.0 % lower in relation to the matrix. The treatment carried out in the loofahs increased the mechanical strength of the composite and decreased the humidity absorption. The composite showed lower mechanical behavior than the matrix for all the formulations. The composite also demonstrated itself to be feasible for thermal applications, with a value of thermal conductivity of less than 0.159 W/m.K, ranking it as a good thermal insulator. For all formulations/settings a low adherence between fibers and matrix occurred, with the presence of cracks, showing the fragility due to low impregnation of the fiber by the matrix. This composite can be used to manufacture structures that do not require significant mechanical strength, such as solar prototypes, as ovens and stoves.

Caracterização de um compósito utilizando cimento com agregado de resíduo plástico e resíduo de gesso

The demand for environmental comfort in construction systems within the insulation and thermal comfort, plus the advent of new laws regulating the minimum requirements of comfort, disposal of solid industrial waste, construction waste, the requirements of consumers by adopting construction methods "cleaner", encouraged the development of this work. Aims technologically characterize the composite proposed in three types of samples (10%, 30% and 50% of thermoset plastic industrial waste) and raw materials: gypsum waste, cement and plastic thermosetting industrial waste in order to produce the composite with properties of thermal insulation: conductivity, thermal diffusivity, specific heat and resistivity. The physical, structural and morphological properties of the raw materials were investigated by thermogravimetry analysis (TG / DSC), X-ray diffraction (DRX), X-ray fluorescence (FXR) and scanning electron microscopy (MEV). Obtaining mechanical properties through the compression strength test. The analysis results indicate characteristics suitable for cement matrix composite production with the addition of thermosetting plastic industrial waste and gypsum waste, with potential application of these materials in composites with properties of thermal insulation. Finally, assessing what proportion showed up with better performance. Considering the analysis and testing carried out.

Caracterização de um compósito utilizando cimento com agregado de resíduo plástico e resíduo de gesso

The demand for environmental comfort in construction systems within the insulation and thermal comfort, plus the advent of new laws regulating the minimum requirements of comfort, disposal of solid industrial waste, construction waste, the requirements of consumers by adopting construction methods "cleaner", encouraged the development of this work. Aims technologically characterize the composite proposed in three types of samples (10%, 30% and 50% of thermoset plastic industrial waste) and raw materials: gypsum waste, cement and plastic thermosetting industrial waste in order to produce the composite with properties of thermal insulation: conductivity, thermal diffusivity, specific heat and resistivity. The physical, structural and morphological properties of the raw materials were investigated by thermogravimetry analysis (TG / DSC), X-ray diffraction (DRX), X-ray fluorescence (FXR) and scanning electron microscopy (MEV). Obtaining mechanical properties through the compression strength test. The analysis results indicate characteristics suitable for cement matrix composite production with the addition of thermosetting plastic industrial waste and gypsum waste, with potential application of these materials in composites with properties of thermal insulation. Finally, assessing what proportion showed up with better performance. Considering the analysis and testing carried out.

Un algoritmo híbrido para el problema NRP con interdependencias

En este artículo presentamos un algoritmo híbrido para una variante del problema de la siguiente versión (NRP). En esta variante existe un conjunto de requisitos para los que se dispone de una estimación del esfuerzo necesario para su implementación y de la satisfacción percibida por los potenciales clientes con la inclusión de dichos requisitos. Entre estos requisitos existen relaciones de interdependencia, que establecen a ciertos requisitos como prerequisitos de otros, o que obligan a implementar determinados requisitos simultáneamente en caso de incluirse alguno de ellos en la siguiente versión del producto a desarrollar. Dado un límite superior de esfuerzo prefijado, el objetivo es seleccionar un subconjunto de requisitos que cumpla todas las restricciones y maximice la satisfacción global de los clientes. La propuesta combina heurísticas con técnicas exactas para una versión simplificada del problema. El rendimiento del algoritmo resultante en distintos escenarios realistas se compara con el de otras técnicas metaheurísticas previamente empleadas

Nuevo simulador híbrido cadavérico/sintético para la enseñanza de técnicas intervencionistas para tratamiento del dolor refractario

Se presenta un nuevo simulador para el entrenamiento y evaluación de técnicas intervencionistas bajo visión fluoroscópica en medicina del dolor que permite realizar los procedimientos más utilizados a nivel de cabeza y cuello, tronco, región lumbosacra y pelvis. En el trabajo se desarrolló una inclusión de material óseo cadavérico en material sintético versión no transparente color piel y transparente para entrenamiento en bloqueos bajo visión ecográfica y fluoroscópica combinados. El Nuevo Simulador Híbrido se basó en la inclusión artesanal de material óseo cadavérico dentro de un tejido de material sintético emulando, con elevado realismo, el modelo humano. En la experiencia de los educandos que realizaron los talleres durante el año 2014 expresaron alta satisfacción comparando a pacientes reales, cadáveres frescos y simuladores sintéticos. Este desarrollo permite, como características principales: a) repetir cada procedimiento las veces necesarias para que cada educando alcance un estándar mínimo exigible y disminuya el número y tipo de errores posibles propios de cada técnica; b) entrenar adecuadamente para los procesos de certificación; c) facilitar evaluar la eficacia de entrenar con estos modelos frente al entrenamiento en pacientes reales u otras formas de entrenamiento (simuladores o cadáveres frescos); d) mejorar la accesibilidad por su bajo costo evitando la complejidad de la preservación de tejidos, y e) permitir, en opinión del autor, reducir la curva de aprendizaje en un medio seguro para paciente, educando, docente y el sistema de salud y universitario.