Influência do uso de combustíveis alternativos na síntese por combustão via microondas para a produção de materiais cerâmicos com estrutura espinélio

The development and study of detectors sensitive to flammable combustible and toxic gases at low cost is a crucial technology challenge to enable marketable versions to the market in general. Solid state sensors are attractive for commercial purposes by the strength and lifetime, because it isn t consumed in the reaction with the gas. In parallel, the use of synthesis techniques more viable for the applicability on an industrial scale are more attractive to produce commercial products. In this context ceramics with spinel structure were obtained by microwave-assisted combustion for application to flammable fuel gas detectors. Additionally, alternatives organic-reducers were employed to study the influence of those in the synthesis process and the differences in performance and properties of the powders obtained. The organic- reducers were characterized by Thermogravimetry (TG) and Derivative Thermogravimetry (DTG). After synthesis, the samples were heat treated and characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), analysis by specific area by BET Method and Scanning Electron Microscopy (SEM). Quantification of phases and structural parameters were carried through Rietveld method. The methodology was effective to obtain Ni-Mn mixed oxides. The fuels influenced in obtaining spinel phase and morphology of the samples, however samples calcined at 950 °C there is just the spinel phase in the material regardless of the organic-reducer. Therefore, differences in performance are expected in technological applications when sample equal in phase but with different morphologies are tested

Síntese de pigmentos cerâmicos inorgânicos nanométricos e encapsulados com estrutura core-shell pela rota dos precursores poliméricos

The present work has as objective the development of ceramic pigments based in iron oxides and cobalt through the polymeric precursor method, as well as study their characteristics and properties using methods of physical, chemical, morphological and optical characterizations.In this work was used iron nitrate, and cobalt citrate as precursor and nanometer silica as a matrix. The synthesis was based on dissolving the citric acid as complexing agent, addition of metal oxides, such as chromophores ions and polymerization with ethylene glycol. The powder obtained has undergone pre-ignition, breakdown and thermal treatments at different calcination temperatures (700 °C, 800 °C, 900 °C, 1000 °C and 1100 °C). Thermogravimetric analyzes were performed (BT) and Differential Thermal Analysis (DTA), in order to evaluate the term decomposition of samples, beyond characterization by techniques such as BET, which classified as microporous materials samples calcined at 700 ° C, 800 º C and 900 º C and non-porous when annealed at 1000 ° C and 1100 º C, X-ray diffraction (XRD), which identified the formation of two crystalline phases, the Cobalt Ferrite (CoFe2O4) and Cristobalite (SiO2), Scanning Electron Microscopy (SEM) revealed the formation of agglomerates of particles slightly rounded;and Analysis of Colorimetry, temperature of 700 °C, 800 °C and 900 °C showed a brown color and 1000 °C and 1100 °C violet

Efeito de argilas organofílicas na estrutura e propriedades de nanocompósitos de poli(metacrilato de metila)

Nacomposites of polymers and lamellar clayminerals, has generated high scientific and technological interest, for having mechanical properties and gas barriers differentiated of polymers and conventional composites. In this work, it was developed nanocomposites by single screw extruder and injection, utilizing commercial raw material, with the goal to investigate the quality of new developed materials. It was evaluated the influence of the content and the kind of clay in the structure and in the nanocomposites properties. It was used regular and elastomeric poly (methyl methacrylate) (Acrigel LEP 100 and Acrigel ECP800) and six montmorillonites (Cloisite 10A, 11B, 15A, 20A, 25A e 30B) at the concentration of 1% e 3% in weight. The nanocomposites were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), colorimetric, optical transparency, flexural and tensile tests, Rockwell hardness and esclerometry. It was founded that is possible to obtain intercalated and exfoliated nanocomposites PMMA/MMT, and the top results was obtained in the materials with 1%in clay weight organophilizated with 2M2HT (Cloisite 15A and 20A) presented intercalate and hybrid morphology (exfoliated and flocullated). The ones that was produced with organophilizated clay with 2MHTL8 (Cloisite 30B) had excellent visual quality, but the majority presented hybrid morphology. In the materials processed with organophilizated clay with MT2ETOH (Cloisite 30B), there were color change and loss of transparency. It occurs improvement in a few mechanical properties, mainly in the materials produced with PMMA elastomeric (Acrigel ECP800), being more significant, the increase in the resistance to stripping in those nanocomposites

Estrutura da população de Coleodactylus natalensis Freire, 1999 (Squamata: Sphaerodactylidae) no Parque Estadual Dunas de Natal, Rio Grande do Norte, Brasil

Coleodactylus natalensis Freire, 1999, an endemic species of Atlantic Forest fragments around the Natal municipality, Rio Grande do Norte State, Brazil, has as type locality the Parque Estadual Dunas de Natal (05º48 S to 05º53 S and 35º09 W to 35º12 W), one of the largest restinga (herb and shrub association on sand dunes along the Brazilian coastline) associate fragment, surrounded by urban zone, placed on setentrional Atlantic Forest limits. We made estimates on populational density, spatial distribution, habitat and microhabitat preferences and feeding ecological aspects like sazonal and sexual variations on diet, prey electivities and niche breadth. We randomly sampled ninety-six 50m2 quadrants in each of the four habitats identified in the study area. Were collected 49 specimens and their stomach contents were analyzed; prey items found were correlated with leaf-litter invertebrates from habitat samples. We found a 98,5 ± 75,5 individuals/ha density, in grouped distribution pattern on densest habitats and random distribution on others habitats. This species lives mostly on leaf-litter in forest habitats, in higher humidity points, with lower temperatures, deeper leaf litter and lower sea level elevations than the randomly chosen points in the study area. Isopoda and Aranae were the most important prey categories in numeric, frequency and volumetric terms. Niche breadth has an intermediate value and was variable in sexual and in habitat terms. There was no correlation between morfometric measures and prey size on diet. The C. natalensis population studied seems to be diet opportunist, although selects larger prey items. The Parque Estadual das Dunas do Natal has several indications of anthropic pressure from the surrounding urban area that may affects the local C. natalensis population. Thus, the fragility of this species calls for urgent conservation efforts

Estrutura da população de Microcerotermes exiguus ( Isoptera: Termitidae) e sua partuicipação no consumo de madeira em uma área de caatinga, Nordeste, Brasil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Ecologia trófica em uma taxocenose de anfíbios: estrutura, filogenia e especialização individual

Historically, ever since the pre-Darwinian naturalists interspecific competition was considered the main force responsible for structuring ecological communities. This interpretation lost strength in the late 70s and throughout the 80s giving room for other views, which consider other factors such as predation, parasitism and the phylogenetic inertia more important. Studies on changes in the trophic niche of a species are still uncommon in general and especially in amphibians. Species considered generalist might actually be a group of individual specialists, or individuals that specialize in a particular category of prey during a period of scarcity of resources, thus reducing intraspecific competition. This work studied the community structure of litter amphibians and trophic variation along the dry and rainy seasons in a population of Leptodactylus macrosternum. Sixteen-litter frog species were studied for their diet. Two central assumptions were tested: 1a) if the community is structured in the niche trophic level, and 1b) if there is a significant difference in the use of food resources by different species (i.e. if the community is structured), the observed structure is the result of ecological interactions or just the current phylogenetic inertia of species. Finally, 2) if there is variation in food resource use between seasons for L. macrosternum. The community showed a structure with respect to the use of food resources, and this structure persisted after taking into account the phylogenetic relationships among species. The diet of Leptodactylus macrosternum varied with the seasons, with a significant degree of individual specialization for the dry season. Patterns of a local community are important to understand its dynamics, and this may play a role in larger- scale processes. Therefore, the studies in community ecology are fundamental to understand and eventually restoring degraded areas

O parto dos caminhos: Formação dos Sindicatos Rurais no Rio Grande do Norte (1960 - 1964)

The present work treats the movements dedicated to reinvidication per land and social rights for the field works, among 1960 and 1964. Trying to understand this question in the Rio Grande do Norte it is necessary to consider the connection between the catholic church and the rural syndicates besides the influence of the Brazilian communist party, and still other social movements and the state. The structures politics local, national and international, had considerable importance to the organization rural potiguares workers. The rural potiguares syndicate appear in 1961 - after a hard organization work starting of the Service of Rural Assistance - and expand itself through state until the middle of 1962. Soon the first big conflicts an important manifestation are perceive, indirectly referring to a increasing movement's performance. The Favoring Progresses chains co quested a biggest influence in the politics destiny of the Rio Grande do Norte, in front of integration among syndicates, educational projects, and favoring progress's politics. But the military coup hired that the hope overflow the field

Avanços e retrocessos na articulação de um pacto territorial: a experiência do PRONAF Infra-Estrutura

Since minetics The economics and political promotion along the necessity of flexibility in states actions admited actors partipction and social controlo on process of construction in local development. The Programa Nacional de Fortalecimento à Agricultura Familiar (PRONAF) by this framework consists suprass the specific points about contry world in order to embrace territorial dimension of development, focalizing actions that estimulate co-operative pratices among local agents. This work proposal intends to identify advances and regression of PRONAF Infra-estrutura (Framework) by one territorial pact organization considering its administration about mechamisms on advantage conmflicts between distinct actor and their ables to atimulates a construction of new relationships between governors and population. Undderstanding PRONAF action like a process that come from its instrumental proportion surpass looking for substantial elements constructionm on intervention of local development considering administration mechamisms in São Paulo do Potengi (RN) city-council-starting by Conselho Municipal de Desenvolvimento Rural as well changes of institutional arrangement with território da Borborema erection. Throngh documental studies, bibliography researches and interviews we indenttfy an articulante power of Territorial pact partnerships like one of these political process and its sector character as their limits

As razões da esquerda radical PCB, PSTU e PSOL: estrutura organizativa e objetivos políticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Reestruturação produtiva na Petrobrás e ação sindical dos petroleiros do RN

Ce travail a l objectif d analyser la question de la restructuration productive dans la Petrobrás/ RN et les implications possibles sur l action syndicale du Sindipetro/RN pendant la période 1995 2003. La restructuration productive dans la Petrobrás/RN commence dans la décennie 1990 quand l entreprise, au niveau national, décide d adhérer au Programa Brasileiro de Qualidade e Produtividade PBQP lancé par le gouvernement Collor comme motivation et priorité pour que les entreprises s adaptent à l ouverture de l économie brésilienne au marché extérieur. De ce fait, la Petrobrás/RN afin de se maintenir dans le marché compétitif et mondialisé , adopte des techniques administratives basées sur la philosophie de la qualité totate, met au point des inovations technologiques et organisationnelles, tout en altérant sa base technique et adopte, encore, la tertiairisation de quelques activités visant à la reduction des coûts. De telles mesures ont atteint de façon remarquable l action du Sindipetro/RN qui commence alors à agir selon la logique de la politique néo-libérale du gouvernement de conduite anti-syndicale. Face à ces faits le syndicat a rédéfini ses actions dans le but de trouver des manières de poursuivre les luttes syndicales dans cette conjoncture de difficultés dans les relations de travail. Celui-ci s engage donc à entamer les négociations comme stratégie afin de préserver les privilèges de la catégorie et d éviter la perte des droits acquis

Estrutura econômica, mercado de trabalho e evolução sócio-ocupacional no Rio Grande do Norte 2001 a 2008: reflexo de uma condição mercantil e estruturalmente periférica

The aim of this thesis was to investigate the evolution of the socio-occupational status in Rio Grande do Norte from 2001 to 2008, based on the characterization of the socio-economic status of this State from the analysis of labor market norte-rio-grandense . The study, specifically, drew a comparison between the dynamics of the labor market in Rio Grande do Norte and the capital city, Natal. From this perspective, the purpose was to make a relationship between the social division of labor and its effects on the socio-spatial division, represented in the "macro scale" by the federal unit and the "micro level" for the capital; locus of economic and population concentration. The collection of data on the labor market had as a major source PNAD/IBGE, characterizing the labor market in many ways: people of working age, economically active population and employed and unemployed people, classified by age, sex, color, education, income and social protection condition. However, as for the socio-occupational division, we follow the methodology used by the research group on national television, based in IPPUR /UFRJ, called Monitoring of the Metropolis," which rallied twenty-four groups that aggregate the occupations found in the PNAD/IBGE, in eight groups of socio-occupational categories, according to the similarity between them. It was used in the socio-spatial cutting two relevant discussions, which are inter-related and were characterized as crucial points in developing the research problem: the former was related to the influence of the hegemony of merchant capital in the labor market in Rio Grande North and, the latter, it referred the socio-economic relations between the territory and the variable occupation. Lastly, the results all indicated that in Rio Grande do Norte, as a peripheral state, has suffered the devastating influence of the hegemony of capital purely commercial basis, where "wealth" of capitalism is generated through the sphere of mere movement of goods and services rather than a productive process due to the social relations of production more advanced. We have a little advanced economic structure, with a tertiary sector that has propagated under-employment or disguised unemployment. Similarly, the agricultural sector has been presented as an example of greater social degradation of working conditions in the state. The secondary sector, in turn, also was not behind this uncertainty; on the contrary, confirmed that condition, with poor levels of income, low education of the workforce and a high degree of social helplessness, even in the state capital, space full urban area, which although always appear with a favorable condition compared to Province, in practically most of the variables studied, was also reflected at the same time the author of a structurally underdeveloped condition

Evangelizar e politizar :O sentido da atuação da Igreja Católica com os sindicatos dos trabalhadores rurais no Seridó potiguar (1964-1979)

The purpose of this work is to analyze the influence of the Catholic Church on rural worker s union in the Seridó potiguar region between 1964 to 1979. To the work developed by the Church is connected the beginning of worker s union in the Seridó region. In this way, this research tries to understand what is also the politic direction of the labor s union by means of the Cathólic Church that througt a process of creating Leagues have been looking for reinforcing and protecting catholicism as a way of maintaining its believers and distancing them from others movements such as Peasant League and the influence of Brazilian Communist Party. We use as sources oral narratives and newspaper A Folha , wich was published by the Parish Church of Caicó (RN) between 1954 to 1967. Some wrintten documents produced by worker s union from the Seridó region were also used

Estrutura genética populacional de Heliconius erato e Heliconius melpomene (Lepidoptera: Nymphalidae) em fragmentos de Mata Atlântica do Rio Grande do Norte

Extensive studies using molecular markers on butterflies have shown how a highly fragmented landscape may result in the reduction of gene flow among patches of habitat and, consequently, increase genetic differentiation among populations. However, little is known about Heliconius geographical structure and the effects of fragmentation on the connectivity of populations. Furthermore, findings on the effects of the population structure on the dynamics of mimicry evolution in Heliconius butterflies need to be tested in H. erato and H. melpomene specimens found in other locations other than Central and northern South Americas. For the present study, we had two motivations: (1) compare the population structure of H. erato and H. melpomene given the highly fragmented Brazil s Atlantic Forest habitat; and (2) studying population structure of co-mimics could give us insights into the dynamics of mimicry evolution. For this, we analysed the spatial structure and connectivity of eight populations of Heliconius butterflies, in a total of 137 H. erato specimens and 145 H. melpomene specimens, using nine microsatellites loci, 1144 AFLPs markers and 282 mitochondrial DNA sequences. In general, both species exhibited evidence of population subdivision but no isolation by distance indicating some extent of genetic differentiation among populations. Contrary to Kronforst & Gilbert s (2008) Costa Rican Heliconius, H. melpomene exhibited more genetic differentiation than H. erato based on nuclear markers. However, for mitochondrial DNA, H. erato populations showed more genetic differentiation than H. melpomene. Our results corroborate to other studies on Heliconius butterflies concerning the pronounced population subdivision and local genetic drift found in this genus. Nevertheless, the pattern of this differentiation varies significantly from the pattern found in studies conducted in Central America, where H. erato is generally more differentiated and structured than H. melpomene, based on nuclear markers. This different pattern may reflect different evolutionary histories of Heliconius species in Northeastern Brazil s Atlantic Forest

Estrutura populacional e aspectos reprodutivos do Octopus insularis Cephalopodas: Octopodidae: implicações para o manejo da pesca de polvo no município de Rio de Fogo-RN

In northeastern Brazil, Octopus insularis is the most commercially important cephalopod species and its capture has been performed for several years by the lobster fishermen in the region. In order to obtain information about the reproductive biology, 1108 specimens were collected between November 2009 and September 2011 in the landings and fish markets of Rio do Fogo (RN). For each specimen the mantle length (CM) and total fresh weight (PT) were recorded. Gonads of 264 males and 295 females were examined macroscopically and histologically to assess sexual maturation and determine reproductive indices. Four reproductive stages were determined for males (immature, maturing, mature and post-mature) and females (immature, early maturing, late maturing and mature). The average of eggs recorded in the female s gonads was 93.820 and 39 was the average of spermatophores found in male Needham s complex. Spermathecae with sperm were found in females with 69 mm CM (immature). Males and females become sexually mature at 64.41 and 98.50 mm of CM, respectively. The weight at sexual maturity was 270 g for males and 630 g for females. The values of the size and weight at sexual maturity found in this study show that males mature at smaller sizes than females. For both sexes the maturation peaks occurred in February and November 2010 and also in September 2011. The periods of maximum reproductive activity lasted about 3 months and it seems to occur every 7 10 months. Only one spent female (stage V) was found and the number of mature females was low. Presumably, mature females migrate to deep waters with complex habitat to protect the offspring, indicating that fishery by snorkeling with maximum depth of 15 meters is not reaches this part of the stock. Finally, it is noticeable the importance of the establishment of management strategies for the exploitation of O. insularis different of the ones used for O. vulgaris, once the species have distinct biological features

Influência das mudanças climáticas na estrutura funcional da comunidade fitoplanctônica em um reservatório da região do semiárido

The Brazilian Northeast is the most vulnerable region to climatic variability risks. For the Brazilian semi-arid is expected a reduction in the overall rates of precipitation and an increase in the number of dry days. These changes predicted by the IPCC (2007) will intensify the rainfall and droughts period that could promote the dominance of cyanobacteria, thus affecting the water quality of reservoirs, that are most used for water supply, in the semi-arid. The aim of this study was to evaluate the effects of increasing temperature combined with nutrient enrichment on the functional structure of the phytoplankton community of a mesotrophic reservoir in the semi-arid, in the worst case scenario of climate change predicted by the IPCC (2007). Two experiments were performed, one in a rainy season and another in the dry season. In the water sampled, nutrients (nitrate and orthophosphate) were added in different concentrations. The microcosms were submitted to two different temperatures, five-year average of air temperature in the reservoir (control) and 4°C above the control temperature (warming). The results of this study showed that warming and nutrient enrichment benefited mainly the functional groups of cyanobacteria. During the rainy season it was verified the increasing biomass of small functional groups of unicellular and opportunists algae such as F (colonial green algae with mucilage) and X1 (nanoplanktonic algae of eutrophic lake systems). It was also observed an increasing in total biomass, in the richness and diversity of the community. In the dry season experiment there was a greater contribution in the relative biomass of filamentous algae, with a replacement of the group S1 (non-filamentous cyanobacteria with heterocytes) for H1 (filamentous cyanobacteria with heterocytes) in nutrient- enriched treatments. Moreover, there was also loss in total biomass, species richness and diversity of the community. The effects of temperature and nutrients manipulation on phytoplankton community of reservoir Ministro João Alves provoked changes in species richness, the diversity of the community and its functional composition, being the dry period which showed the highest susceptibility to the increase in the contribution of potentially toxic cyanobacteria with heterocytes