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.

Efeitos do treino de marcha em esteira com adição de carga ao membro inferior não parético de indivíduos com acidente vascular cerebral: ensaio clínico controlado e randomizado

Introduction: Gait after stroke is characterized by a significant asymmetry between the lower limbs, with predominant use of the non-paretic lower limb (NPLL) over using the paretic lower limb. Accordingly, it has been suggested that adding load/weight to the NPLL as a form of restricting the movement of this limb may favor the use of the paretic limb, reducing interlimb asymmetry. However, few studies have been conducted up to this moment, which only investigated the immediate effects of this practice. Objectives: 1) Investigating whether there is an influence of adding load to the NPLL during treadmill training on cardiovascular parameters and on gait performance of individuals with stroke, compared to treadmill training without load addition; 2) Analyzing the effects of treadmill training with and without load added to the NPLL on kinematic parameters of each lower limb during gait; 3) Analyzing the effects of treadmill training with and without load added to the NPLL on measurements of functional mobility and postural balance of these patients. Materials and Methods: This is a randomized single blinded clinical trial involving 38 subjects, with a mean age of 56.5 years, at the subacute post-stroke phase (with mean time since stroke of 4.5 months). Participants were randomly assigned into an experimental group (EG) or control group (CG). EG (n= 19) was submitted to gait training on a treadmill with the addition of load to the NPLL by ankle weights equivalent to 5% of body weight. CG (n= 19) was only submitted to gait training on a treadmill. Behavioral strategies which included home exercises were also applied to both groups. The interventions occurred daily for two consecutive weeks (Day 1 to Day 9), being of 30 minutes duration each. Outcome measures: postural balance (Berg Functional Balance Scale – BBS), functional mobility (Timed Up and Go – TUG; kinematic variables of 180° turning) and kinematic gait variables were assessed at baseline (Day 0), after four training sessions (Day 4), after nine training sessions (Day 9), and 40 days after completion of training (Follow-up). Cardiovascular parameters (mean arterial pressure and heart rate) were evaluated at four moments within each training session. Analysis of variance (ANOVA) was used to compare outcomes between EG and CG in the course of the study (Day 0, Day 4, Day 9 and Follow-up). Unpaired t-tests allowed for intergroup comparison at each training session. 5% significance was used for all tests. Results: 1) Cardiovascular parameters (systemic arterial pressure, heart rate and derivated variables) did not change after the interventions and there were no differences between groups within each training session. There was an improvement in gait performance, with increased speed and distance covered, with no statistically significant difference between groups. 2) After the interventions, patients had increased paretic and non-paretic step lengths, in addition to exhibiting greater hip and knee joint excursion on both lower limbs. The gains were observed in the EG and CG, with no statistical difference between the groups and (mostly) maintained at follow-up. 3) After the interventions, patients showed better postural balance (higher scores on BBS) and functional mobility (reduced time spent on the TUG test and better performance on the 180° turning). All gains were observed in the EG and CG, with no statistically significant difference between groups and were maintained at follow-up. Conclusions: The addition of load to the NPLL did not affect cardiovascular parameters in patients with subacute stroke, similar to treadmill training without load, thus seemingly a safe training to be applied to these patients. However, the use of the load did not bring any additional benefits to gait training. The gait training program (nine training sessions on a treadmill + strategies and exercises for paretic limb stimulation) was useful for improving gait performance and kinematics, functional mobility and postural balance, and its use is suggested to promote the optimization of these outcomes in the subacute phase after stroke.

El grafismo contemporáneo en la creación artística. Aspectos históricos y estéticos

En esta investigación se pretende estudiar el uso que se ha hecho del grafismo en aquellos procesos creativos que tendrían la intencionalidad de devenir en obras de carácter plástico-artístico Consideremos que todo diagrama tienen una intencionalidad; se carga de valor creativo en el mismo momento que pretende crear o recrear una realidad. Pero no por ello habría que suponer que su valor pueda contemplarse como artístico. Esta valoración habría que hacerla en función de la significación, inmediata o subsiguiente, que se le dé a estos esquemas: el que lleguen a ser considerados como elementos de un proceso con una finalidad artística concreta. La significación aquí estaría definida por el dominio del que habla Deleuze en su conferencia "¿Qué es el acto de creación?" en 1987. " [...]Uno no tiene una idea “en general”. Una idea está “ya vista de antemano”, está ya en tal autor, en tal dominio determinado. Quiero decir que una idea, ya sea una idea en pintura, ya sea una idea en novela, ya una idea en filosofía, como una idea en ciencia, evidentemente no es lo mismo."3 Aquí nos encontramos con la intencionalidad que cada autor le quiera dar a su obra. Pero la resignificación que se hace de la obra cuando esta se contempla en diversos momentos o lugares, ¿afecta también a estos elementos? Si los consideramos como parte de la obra, aunque en su momento no fuera así, es más que probable. La obra final, entonces, no siempre existe. Pero aún es más frecuente, sobre todo en ciertas épocas o culturas, que sea el material conducente a la obra final lo que ha desaparecido, aunque se tenga constancia de su existencia. El que esta documentación del proceso se haya conservado o no, no parece afectar de manera directa a la obra final, pero sí nos habla de manera directa de como se contempla el arte, por lo que esta significativa ausencia también se tiene en cuenta a la hora de realizar este estudio...

O uso da PCR em tempo real para o estudo da carga parasitária e dos níveis transcricionais durante a infecção experimental por Trypanosoma cruzi

Trypanosoma cruzi is causative agent of Chagas disease, one of most neglected tropical diseases. Estimated that about 11 million people worldwide are infected by T. cruzi and about 6 to 7 million people are at risk in endemic areas. During the process of invasion of host and parasite interact enabling signal transduction and gene expression modulation in response to invasion. The diversity of activated proteins and pathways to repair the damage by disruption of the plasma membrane interest to us and thus present study developed a new form of detection and quantitation by polymerase chain reaction in real time (qPCR) of parasitic load T. cruzi and quantified transcriptional levels relative (RT-qPCR) of dysferlin, Sphingomyelin acid esferase (ASM), transcription factor EB (TFEB) Galectins 1 and 3 and Annexin A2. This study demonstrated that quantification by real time PCR using primers P21fw and P21rv was specific and sensitive for detection of T. cruzi in vivo and in vitro, as well as transcriptional levels of genes related to cytoskeletal organization and repair plasma membrane are modulated in response to damage generated by parasite.

Sistema de carga bidirecional para veículo elétrico

As preocupações com o elevado consumo de combustíveis fósseis e a crescente poluição atmosférica conduziram ao desenvolvimento dos veículos elétricos e dos veículos elétricos híbridos. O crescimento do parque automóvel elétrico levou à necessidade de considerar a sua integração na rede eléctrica, ao nível dos impactos estimados, mas também na sua potencial contribuição para uma gestão inteligente do sistema, funcionando como um buffer da energia produzida, permitindo desacoplar a produção do consumo, e assim melhor a eficiência global. Neste trabalho foi efetuado um estudo relacionado com a ligação bidirecional entre os veículos eléctricos e a rede eléctrica que permitirá o uso das baterias instaladas nos veículos participar nesse apoio à rede, debruçando-se primeiramente sobre o desenvolvimento das baterias que permanecem como elos mais fracos. Utilizando diferentes ferramentas de simulação e de análise de resultados foi depois efetuado um estudo sobre dois sistemas alternativos capazes de implementar o conceito V2G respeitando as restrições do ponto de vista normativo. Os resultados obtidos a partir de uma simulação coordenada entre os programas Simulink/Matlab e PSIM permitiram demostram o bom funcionamento dos 2 sistemas propostos, permitindo ficar com a convicção que o conversor multinível será capaz de proporcionar os resultados desejados com um menor tempo de resposta.

Monitorização da carga de treino em Futsal: estudo piloto com jogadores amadores juniores e seniores

Este foi um estudo piloto que pretendeu monitorizar a carga de treino em Futsal, com jogadores amadores juniores e seniores. A amostra do presente estudo foi composta por 8 jogadores de Futsal do sexo masculino, 4 juniores com idade média de 16.5±0.5 anos (estatura de 1.67±0.04 m e 59.2±2.21 Kg de massa corporal) e 4 seniores com idade média de 27.2±2.7 anos (estatura de 1.71±0.05 m e 69.7±7.5 Kg de massa corporal). Os jogadores competiam nos campeonatos distritais amadores de Futsal, na sua categoria, organizados pela Associação de Futebol de Leiria. Para a realização deste estudo recorreu-se a 4 unidades do ZephyrTM BioHarnessTM System (Zephyr Technology, Auckland, New Zealand). Trata-se de um sistema de monitorização wireless de dados fisiológicos e que tem a capacidade de medir a frequência cardíaca (FC), frequência respiratória (FR) e acelerometria (ACC). Os resultados obtidos mostram que o sistema utilizado registou as variáveis que se pretendiam estudar, sem limitações para o atleta, isto é, sem cabos ou artefactos, que limitassem os movimentos durante a unidade de treino. Verificou-se também que, no somatório de 8 unidades de treino, a frequência cardíaca média no grupo de juniores foi mais elevada do que a dos jogadores seniores (p = 0.029). A monitorização permitiu avaliar a intensidade das unidade de treino, permitindo identificar as respostas fisiológicas por jogador e por treino. Utilizando esta tecnologia é possível fazer um acompanhamento monitorizado de cada atleta por forma a analisar a sua adaptação e evolução fisiológica e fazer uma prescrição/planificação da sessão de treino mais adaptada a cada atleta.

Estudio de optimización técnico-económica de la desalación como carga diferida en un sistema aislado

[ES]Este trabajo pretende estudiar el impacto que la desalación tendría en una micro-red abastecida por fuentes de energía renovables en un entorno en vías de desarrollo. Para ello, se ha estudiado el efecto económico de la inclusión de la desalación, utilizando distintas estrategias. Se ha demostrado que estos sistemas pueden ofrecer una solución viable al abastecimiento de agua dulce en poblaciones en vías de desarrollo

Diseño de máquina para ensayos de Creep, Creep-Fatiga y falla por carga sostenida.

El objetivo del presente trabajo es el diseño de una máquina para ensayos de Creep, con capacidad de aplicar carga variable. Se busca una máquina liviana, desmontable y fácilmente transportable entre laboratorios. El diseño de la máquina parte de una ingeniería básica, pasando por una etapa de detalle y finalizando en la fabricación y montaje de la misma. Se incluye en el diseño un sistema de adquisición y control de carga. Se diseñó y construyó una máquina accionada por resorte capaz de aplicar 5 kN. Se evalúa su respuesta ante distintos programas de carga. El control de carga es capaz de seguir referencias con evolución suave en el tiempo sin mayores dificultades y mantener la carga constante durante intervalos largos de tiempo. La adquisición de datos se realiza mediante un módulo QuantumX y transductores de desplazamiento y carga HBM.

Validación de un instrumento para evaluar la carga del cuidador en parálisis cerebral

Esta investigación pretende desarrollar y validar una escala para evaluar la carga del cuidador del niño con parálisis cerebral (PC) de niveles funcionales GMFCS (Gross Motor Function Classification System) IV y V.

Estudo numérico e experimental da estabilidade e repartição de carga na tíbia na revisão da ATJ

Este estudo visou a realização de uma análise comparativa da estabilidade e transferência de carga do prato tibial na interface osso-cimento aquando da utilização de diferentes tipos de hastes (press-fit e cimentada) na revisão da artroplastia total do joelho (ATJ).

Diseño de máquina para ensayos de Creep, Creep-Fatiga y falla por carga sostenida.

El objetivo del presente trabajo es el diseño de una máquina para ensayos de Creep, con capacidad de aplicar carga variable. Se busca una máquina liviana, desmontable y fácilmente transportable entre laboratorios. El diseño de la máquina parte de una ingeniería básica, pasando por una etapa de detalle y finalizando en la fabricación y montaje de la misma. Se incluye en el diseño un sistema de adquisición y control de carga. Se diseñó y construyó una máquina accionada por resorte capaz de aplicar 5 kN. Se evalúa su respuesta ante distintos programas de carga. El control de carga es capaz de seguir referencias con evolución suave en el tiempo sin mayores dificultades y mantener la carga constante durante intervalos largos de tiempo. La adquisición de datos se realiza mediante un módulo QuantumX y transductores de desplazamiento y carga HBM.