Adição de geomanta e tecido não tecido de polipropileno em cimentos geopoliméricos de pega rápida

Geopolymers are cementing materials that depict a number of advantages compared to Portland cement. Contrary to the latter, geopolymers are synthesized at room temperature, thus significantly reducing the emission of CO2 to the atmosphere. Moreover, the composition and synthesis reactions can be tailored to adjust the setting time of the material as well as its compressive mechanical strength. It is then possible to produce geopolymeric cements with short setting times and high compressive strength, although relatively brittle. The objective of the present study was to produce and characterize composite materials by reinforcing fastsetting geopolymeric matrixes with polypropylene geosynthetics (geomats and geotextiles) in an attempt to improve the toughness and tensile strength of the cementing material. Geosynthetics have been increasingly used to reinforce engineering structures, providing higher strength and better toughness. In particular, polypropylene nonwoven and geomats depict other attractive properties such as low density, durability, impact absorption and resistance to abrasion. Fast-setting geopolymers were then synthesized and reinforced with polypropylene nonwoven and geomats. The mechanical strength of the materials, reinforced or not, was characterized. The results showed that relatively short setting times and adequate flowing behavior were achieved by adjusting the composition of the geopolymer. In addition, it is possible to improve the fracture resistance of geopolymeric cements by adding polypropylene geosynthetics. The best results were achieved by reinforcing geopolymer with polypropylene TNT

Estudo das propriedades mecânicas de biocompósitos de polipropileno reforçados com fibras naturais

This research presents an approach to the addition of curauá fibers and licuri fibers in a polypropylene resin matrix, such as an alternative proposal to reinforce the polymeric composites. Fiber content of 0 %, 5 %, 10 %, and 20% were analyzed for verification of their mechanical properties comparing them, inclusive with the properties of polypropylene. The grainulated biocomposites had been prepared in an extrusora. The test bodies had been molded by injection and submitted to the mechanical essays uniaxial traction, flexion on three points, impact, in addition to thermal tests (HDT). These biocomposites had been also subjected the essay physicist-chemistry index of fluidity (IF). It was observed that the biocomposites of PP with 20% curauá, obtained bigger increase in the modulus of elasticity and a bigger reduction in the resistance to the impact. In the mechanical behavior, for all the biocomposites, these were increases in values of the limit of drainage and tension of rupture, when tested by uniaxial traction, as they added the fibers. Another important point was the increase of the resistance the flexion. It was also noted that the addition of fibers reduced the thermal degradation of the mixture natural fibers / polypropylene.

Degradação fotoquímica de efluentes industriais contendo polipropileno e isoniazida

One of the main impacts to the environment is the water pollution, where the industrial sector is one of the main sources of this problem. In order to search for a solution, the industrial sector is looking forward to new technologies to treat its wastewaters with the goal to reuse the water in the own process. In this mode, the treatment presents a reduction in its costs with the water suply. One of these technologies that are getting more and more applications is the advanced oxidative processes (AOP´s). In this work two industrial wastewaters have been studied, i.e., containing polymers and pharmacus. In the case of the wastewaters with polymers the UV/H2O2 process has been applied with a systematic series of experiments, using irradiation from a mercury lamp and also solar. The following variables of the UV/H2O2 process for the polymers wastewaters have been studied systematically with the lamp reactor: mode of addition of hydrogen peroxide, temperature, time of reaction, hydrogen peroxide concentration and power of the lamp (80, 125, 250 and 400W). The results demonstrated to be satisfactory, obtaining rates of organic charge removal of 100% in 120 minutes of reaction. The studied variables for the experiments with solar irradiation using polymers wastewaters were only the time of reaction, the mode of addition and concentration of the hydrogen peroxide. The results with the solar irradiation demonstrated to be not satisfactory, reaching maximum of 22% of TOC removal in 240 minutes of reaction. This is in accordance with the fact that the solar source has only 5% of low UV irradiation. With respect to the photodegradation of the pharmacus wastewaters, the process UV/H2O2 and photo-Fenton have been applied. As a source of photons, in this case, a mercury UV lamp of 80 W has been used. The studied variables for the experiments with artificial irradiation with the pharmacus wastewaters were: initial concentration of the pollutant, concentration of Fe2+ and time of reaction. The results demonstrated a degree of degradation fairly satisfactory, showing a maximum conversion value of 46% in 120 minutes

Posicionamento estratégico de destinos: uma análise através da percepção dos operadores de Turismo da cidade de São Paulo sobre o destino Natal, Brasil

El turismo constituye una actividad propulsora de mejorías económicas y sociales en incontables lugares alrededor del mundo, y la ciudad de Natal se posiciona como uno de los principales destinos turísticos del Nordeste brasileño. De ese modo, el objetivo del presente estudio consistió en analizar el posicionamiento estratégico del destino Natal por medio de la percepción de los operadores de turismo de la ciudad de São Paulo, principal mercado emisor de turistas del país. El estudio de carácter descriptivo-exploratorio utilizó un abordaje cualitativo y tuvo, como universo de investigación, operadoras de turismo de la capital paulista que comercializan el destino Natal. En la colecta de datos, se utilizaron la investigación bibliográfica y el estudio de campo, siendo este último efetivado por medio de un guión de entrevista semiestruturado. Ya la técnica utilizada para el análisis de los datos fue el análisis de contenido, iniciada mediante selección del material recolectado y concluida con el proceso de categorización. Cuanto a los resultados del estudio, se percibió que el paulistano que viaja al destino Natal tiene un perfil demográfico que sugiere a la práctica del turismo sustentable, está a la busca del turismo de sol y playa, y valora las bellezas naturales del lugar. Los operadores de turismo entrevistados evaluaron, positivamente, la ciudad de Natal, y destacaron los siguientes atributos del destino: playas, bellezas naturales, hostelería, receptividad de los autóctonas, gastronomía, de entre otros. Además, los respondentes demostraron tener un fuerte encariño al destino. En lo que se refiere a los aspectos negativos, prevaleció la observancia de la ineficacia de los gobiernos locales, donde el deterioro de la malla aérea y la incipiente promoción del destino fueron apuntados como los dos principales gargalos. Al analizar la competencia, se identificó que Fortaleza, Porto de Galinhas y Maceió son los tres principales concurrentes de Natal, siendo el destino pernambucano lo que presenta mejor evaluación. Por fin, se observó que no existe una diferenciación relevante en el destino Natal.