Federal University of São Carlos

About: Federal University of São Carlos is a education organization based out in São Carlos, Brazil. It is known for research contribution in the topics: Population & Microstructure. The organization has 16471 authors who have published 34057 publications receiving 456654 citations. The organization is also known as: UFSCar & Federal University of São Carlos.

Effect of crystallization temperature on the phase transitions of P(VDF/TrFE) copolymers

Abstract: A systematic study was carried out on the effect of the crystallization tem- perature (Tcr), on the phase transitions presented by P(VDF/TrFE) copolymers cast from dimethylformamide (DMF) solution with molar ratios 60/40, 70/30, and 80/20. The results obtained by differential scanning calorimetry (DSC) showed that two- phase transitions are observed only when the copolymer crystallizes above a certain temperature To, and that the temperatures at which these transitions occur are reduced slightly with Tcr increase. It also was observed that when Tcr increases, the intensity of the endotherm corresponding to the lowest temperature transition is increased, whereas the one corresponding to the highest temperature transition is reduced. In order to explain these phenomena, the existence of two ferroelectric and two paraelectric phases is suggested. The conformational differences between like phases occur due to the distinct origin of each one: the best organized phase crystallizes directly from solution, whereas the least organized is the result of a solid phase transition. Wide angle x-ray diffusion (WAXD) diffractograms corroborate this hypothesis. Phase diagrams for samples crystallized below and above To have been proposed. q 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 403-414, 1998

Humidity levels drive reproductive modes and phylogenetic diversity of amphibians in the Brazilian Atlantic Forest

Abstract: Aim The diversity of reproductive modes among amphibians constitutes a striking example of how differences in the biology of species provide important explanations for species distribution patterns on a broad scale. We hypothesize that sites with a higher humidity level will support more modes of reproduction than drier sites and will consequently exhibit a higher phylogenetic diversity. Furthermore, if there is a gradient in the tolerance of reproductive modes to desiccation, there will be a nested pattern in the composition of reproductive modes among sites. Location Twenty-seven forest sites in the Brazilian Atlantic Forest. Methods Through a path analysis approach, we evaluated the direct and indirect effects of the humidity level on the number of reproductive modes, as well as the relative importance of both variables on amphibian phylogenetic diversity. A nestedness analysis was used to quantify the extent to which the compositions of both species and reproductive modes in drier sites correspond to subsets of those in sites with higher annual precipitation. Results We found that the reproductive modes present in drier sites are nonrandom subsets of those present in sites with higher humidity levels. Because reproductive modes are phylogenetically conserved among amphibians, sites with a greater number of reproductive modes supported greater phylogenetic diversity. Sites with high precipitation throughout the year provided suitable environmental conditions for a larger number of reproductive modes, whereas sites with low precipitation and typical seasonal climates supported only those reproductive modes specialized to resist desiccation. Main conclusions Our results show that humidity-related variables are key environmental factors related to both the richness of reproductive modes and phylogenetic diversity. Our results support the hypothesis that the higher phylogenetic diversity found in moister sites reflects differences in the tolerance to desiccation among different reproductive modes. Given that reproductive modes are associated with susceptibility to desiccation, their incorporation into explanatory models may trigger a significant advance in the understanding of the mechanisms regulating the species richness and composition of amphibian communities.

Corrosion behavior of supermartensitic stainless steel in aerated and CO2-saturated synthetic seawater

Abstract: This paper discusses the corrosion behavior of supermartensitic stainless steel in CO 2 -saturated synthetic seawater. A comparison is also made with an aerated solution. Potentiodynamic polarization measurements were taken in synthetic seawater with five different chloride contents: 20 000, 30 000, 40 000, 60 000 and 80 000 ppm, and at three different temperatures: 5, 25 and 60 °C. The pitting potential decreased in a logarithmic relation with the chlorine concentration. The pitting potential decreased linearly with increasing temperature. XPS measurements indicated that the presence of CO 2 enriches the Cr content in the oxide layer and that the temperature also favors this enrichment. The pitting potential depends on the stability of passive film. Otherwise, stability is dependent on the composition. So pitting potential is affected by a synergy between the chloride concentration and the saturated CO 2 solution.

Capacidade para o trabalho em indivíduos com lesões músculo-esqueléticas crônicas

Abstract: OBJETIVO: Avaliar o impacto de fatores pessoais, do trabalho e da lesao na capacidade funcional dos trabalhadores com e sem historia de acometimento de lesoes musculo-esqueleticas relacionadas ao trabalho, atraves da aplicacao do indice de capacidade para o trabalho. METODOS: Participaram do estudo 127 trabalhadores da linha de producao de uma empresa multinacional de porte medio. Foi aplicada uma traducao autorizada do indice de capacidade para o trabalho, um questionario elaborado pelo Instituto de Saude Ocupacional da Finlândia, assim como uma escala de dor. Os resultados foram analisados descritivamente, por meio do teste qui-quadrado e pela analise de regressao logistica. RESULTADOS: Todos os fatores pessoais, ocupacionais e clinicos analisados apresentaram relacao significativa com a capacidade para o trabalho. A analise de regressao mostrou que as variaveis de dor e afastamentos, quando associadas, explicam 59% das ocorrencias de baixa capacidade para o trabalho. CONCLUSOES: Diferentes niveis de dor refletiram niveis tambem distintos e equivalentes de perda da capacidade para o trabalho, o que pode sugerir que os relatos de dor sao consistentes. Ou, por outro lado, que ambos - dor e incapacidade - sao baseados em auto-relatos e, portanto, estao permeados pelos mesmos mecanismos de percepcao. Estudos futuros podem contribuir para melhor avaliar essas tendencias.