Desevolvimento de nanocompósitos de poli(metacrilato de metila)/argila processados por mistura no estado fundido

Poly(methyl methacrylate)/clay nanocomposites were prepared by melt mixing using a montmorillonite-rich clay (MMT). The clay in natura was treated with acrylic acid to facilitate the dispersion in the polymer matrix. A masterbatch of PMMA/clay was prepared and combined with the pure PMMA and then subjected to extrusion process using singlescrew and twin-screw extruders followed by injection. Nanocomposites were processed with clay contents of 1, 3, 5 and 8 wt.%. The effect of shear processing on the morphology of the nanocomposites was evaluated by XRD, SEM and TEM. Thermal and mechanical properties of the nanocomposites were investigated through TGA, DSC, HDT, VICAT, tensile and impact tests, to evaluate the effect of the addition of clay to the PMMA matrix. Flammability tests were also conducted to investigate the effect of the addition of clay on the flame retardation properties. SEM images of the nanocomposites indicated the presence of clay agglomerates, which resulted in the reduction of properties such as thermal stability, mechanical strength and impact resistance, and increased the rate of burning for materials processed by both extrusion routes

A rede de marcação e recaptura: o caso de borboletas do gênero heliconius

(The Mark and Recapture Network: a Heliconius case study). The current pace of habitat destruction, especially in tropical landscapes, has increased the need for understanding minimum patch requirements and patch distance as tools for conserving species in forest remnants. Mark recapture and tagging studies have been instrumental in providing parameters for functional models. Because of their popularity, ease of manipulation and well known biology, butterflies have become model in studies of spatial structure. Yet, most studies on butterflies movement have focused on temperate species that live in open habitats, in which forest patches are barrier to movement. This study aimed to view and review data from mark-recapture as a network in two species of butterfly (Heliconius erato and Heliconius melpomene). A work of marking and recapture of the species was carried out in an Atlantic forest reserve located about 20km from the city of Natal (RN). Mark recapture studies were conducted in 3 weekly visits during January-February and July-August in 2007 and 2008. Captures were more common in two sections of the dirt road, with minimal collection in the forest trail. The spatial spread of captures was similar in the two species. Yet, distances between recaptures seem to be greater for Heliconius erato than for Heliconius melpomene. In addition, the erato network is more disconnected, suggesting that this specie has shorter traveling patches. Moving on to the network, both species have similar number of links (N) and unweighed vertices (L). However, melpomene has a weighed network 50% more connections than erato. These network metrics suggest that erato has more compartmentalized network and restricted movement than melpomene. Thus, erato has a larger number of disconnected components, nC, in the network, and a smaller network diameter. The frequency distribution of network connectivity for both species was better explained by a Power-law than by a random, Poissom distribution, showing that the Power-law provides a better fit than the Poisson for both species. Moreover, the Powerlaw erato is much better adjusted than in melpomene, which should be linked to the small movements that erato makes in the network

Uma análise sociodemográfica dos cuidadores formais de idosos institucionalizados no município de Natal/RN, 2012

The aging population and individual have been the subject of a multitude of studies nowadays. This is probably due to the impact of this phenomenon in various sectors of society, like social security, social assistance and public health. The process of aging of the individual imply the demand for specific services, considering the limitations and vulnerabilities of the individual at that stage of life cycle. The growth of the elderly contingent in the last decades raises challenges for policymakers, the family and also for the society at large. In this scenario, long-stay institutions for the elderly (LSIEs) appear as an option to aid and support the elderly and their family, assisting in all or part in the activities of daily living and self-care. Inside these LSIEs we find the professional responsible for the direct care of the elderly, the formal caregiver. In this context, this dissertation presents two main objectives: an analysis of the phenomenon of population aging in a given brazilian municipality Natal / RN, based on the Demographic Censuses of 2000 e 2010; and a social, demographic and economic characterization of the Formal caregiver for the institutionalized elderly in the municipality, evaluating aspects of his quality of life and also analyzing the institutions where they are inserted. Furthermore, we intend to identify demographic, socioeconomic and quality of life factors that are correlated with caregivers quitting the job. The data used in the second part of this work comes from the research project named Long-Stay Institutions for Elderly: abandonment or a family need? . This survey interviewed 92 caregivers in eleven LSIEs in Natal/RN. In the data treatment logistic regressions, cluster analysis and statistical tests were used. The survey revealed that aging in Natal is more pronounced in the older, more traditional districts: Petrópolis, Lagoa Seca and Tirol. It also allowed a broad characterization of the formal caregivers in LSIEs. Most of these professionals are female. The educational level is predominantly complete high school and more. Most caregivers reported being married or in union, or have ever been in a union. Family monthly income is under three times the minimum wage. The mean age is of 37.4 years. The mean time of work as a caregiver was 5.93 years. The associations showed that being woman, not being single, having caregiving training and physical limitations (regarding quality of life) are related to wanting to quit the caregiving job. As for the characterization of the LSIEs, it was found that the philanthropic ones are older and have most (62.5%) of the institutionalized elderly. The institutions managers gave social interaction and affinity with the elderly as the main criteria with which to evaluate and hire caregivers. It is intended with this study to contribute to improving the quality of life of the elderly and their caregiver, providing information on aspects of institutionalization of elderly both in the philanthropic and particular institutions, in Natal/RN; this dissertation may also be used as a starting point for later works

Aproveitamento de resíduo de caulim em cerâmica branca

The world market of Kaolin has been growing as new investments for better quality of materials have been applied. This market produces amounts of dross that are put in the environment in a wrong way, causing damages to it. Trying to reduce these damages, researches have been done in an attempt to use kaolin dross in ceramic. The disposal of kaolin dross in the environment by the industries of the states of Rio Grande do Norte and Paraiba have great impact in society. Usually this dross is disposed clandestinely in places like roads, river banks and lands of small cities. The present work shows the characteristics of the kaolin produced by the mining company in Junco do Seridó, Paraiba state, western Seridó, 300 km from Natal, in the border of both states. After that, researches were done to study its physical and the chemistry characteristics, trying to see if it can be used in white ceramic. The samples got were bolted in fabric of 325# . The technological characteristics tried to use it as a product in white ceramic. For that, it was made a haracterization of the subject matter through enlargement analyses, ATG and ATD, elaborating three formulations that were burned in four different temperatures, 1175, 1200, 1250 and 1300 degrees centigrade up to 30 minutes. After the burning, the subjects were submitted to water absorbing tests, linear retreating, apparent porosity, apparent specific mass, resistance to flexibility and MEV. For one of the mixtures it was obtained demanded properties for a semi porous material

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.