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Utilização da borracha natural no desenvolvimento de elastômeros termoplásticos
(Universidade Federal de São Carlos, 2010-05-28) Rojas, Galia Johanna Alzate; Pessan, Luiz Antonio; https://lattes.cnpq.br/8276650236213537; https://lattes.cnpq.br/0771017207165419
Dynamic vulcanization is a process of vulcanization of an elastomer during melt mixing with a thermoplastic. This process results in an elastomeric alloy material with the properties of a conventional thermoset rubber, but which can be processed as a conventional thermoplastic. In this study, thermoplastic elastomers (TPEs) based on natural rubber (NR)/polyprolylene (PP) with various blend ratios were prepared. The TPEs was obtained by dynamic vulcanization of NR/PP using a sulphur (S)/N-tert-butyl-2- benzothiazolesulphenamide (TBBS) and tetramethylthiuram disulphide (TMTD) curative system during processing in the melt state. The crosslinking formation during the processing was confirmed by the increase in the degree of cure of the systems measured by DSC. The dynamic vulcanization process increases the stiffness of the NR phase in the TPEs and modifies the thermal and mechanical behavior. NR/PP TPEs with high content of NR showed superior mechanical performance compared to the uncrosslinked NR/PP blends in terms of tensile strength and Young s modulus. It was obtained an increase in Young s modulus values of NR70/PP30 TPE of 316% than compared to NR70/PP30 conventional blend. The main reason for the high performance was the increase of degree of cure during the reactive processing that became the NR phase more rigid and contributed to the increase in the mechanical resistance of TPEs.
Ensino de discriminações condicionais em bebês: avaliação do responder por exclusão e treino de emparelhamento de identidade com diferentes estímulos
(Universidade Federal de São Carlos, 2010-05-28) Garcia, Lucas Tadeu; Gil, Maria Stella Coutinho de Alcântara; https://lattes.cnpq.br/1673770301699940; https://lattes.cnpq.br/3292626740859106
Studies on learning by exclusion and stimuli equivalence are usually conducted by means of conditional discriminations teaching procedures. Some recent studies have investigated important variables in procedures for teaching conditional discriminations to babies, both for the maintenance of the subjects in the task and for the establishment of conditional responding in babies. Considering the recent advances in the literature and seeking to develop procedures for investigating relational repertoires in infants, two studies were performed. The first study was divided into two parts whose objectives was: 1A) replicating and adapting to the child care center context a study about conditional discrimination teaching by exclusion for a baby of 17 months, in which photographs were used as stimuli and; 1B ) to evaluate the generality of the procedure employed in the previous study. The second study aimed to investigate the effect of using abstract stimuli and toys stimuli on an identity matching teaching procedure. In Study 1A, the three participants were trained a baseline auditory-visual conditional discriminations with familiar photographs. After that subjects were presented to exclusion and learning evaluation trials. The three participants (between 17 and 19 months) learned the baseline conditional discriminations and chose correctly in all exclusion trials, although they have not demonstrated learning by exclusion. In Study 1B the same procedure was used and only two of three children, aged between 15 and 18 months, learned the baseline relations, although all of them chose the correct stimulus in the exclusion trials. There was evidence of learning by exclusion for some children, however, the performance of infants in the novelty control trials suggested that children could be choosing based on such bias. The results suggest that the presented procedure is a useful tool for the study of exclusion responding in babies and thus enables further investigations on the process. In Study 2, two babies of 17 and 20 months were submitted to an identity matching training with abstract shapes or toys used as discriminative stimuli. The stimuli presentation was made by a mechanical apparatus that allowed the exposure of stimuli in closed and open windows. The programmed consequences varied according to the stimuli training condition. Babies have not learned the identity conditional discriminations in any stimuli conditions, although there was a greater number of corrects choices when the stimuli used were abstract shapes. Nevertheless, it was not possible to obtain conclusive evidence about the effectiveness of the use of those different stimuli conditions on the infant s conditional discrimination learning.
Especiação de metais e sua interação com a matéria orgânica dissolvida em um reservatório artificial
(Universidade Federal de São Carlos, 2010-05-28) Tonietto, Alessandra Emanuele; Lombardi, Ana Teresa; https://lattes.cnpq.br/6737850858443813; https://lattes.cnpq.br/3056194008699912
Environmental degradation of aquatic ecosystems stimulates investigations about the interactions between dissolved organic matter, trace metals and the biota. This study aimed to investigate the speciation of cadmium, copper, lead and zinc in a reservoir subjected to antropic activities. To develop this study, we have chosen Barra Bonita Reservoir (SP), an eutrophic and contaminated ecosystem that receives urban, industrial and agricultural efluents. Water samples were obtained in three locations within the reservoir considering local seasonality (dry winter and rainny summer) during 24 months. The samples were analysed for total, total dissolved, labile and ionic concentrations of the metals, as well as complexation parameters (CL e logK ML) and competition between copper and zinc for the ligands, fluorimetric characterization, and physico-chemical parameters of the water. The results showed a high degree of deterioration of the ecosystem. Independent of sampling location, the concentration order for the metals was Zn>Cu>Pb>Cd (total and total dissolved). In general copper and zinc remained as complexes in the dissolved fraction, while lead was mostly associated with particulate materials. MineqL+ calculations showed that Zn2+ and Cd2+ dominated the labile form, whereas copper and lead remained associated with carbonates. The increased concentration of total dissolved metal showed an increase of copper and zinc complexes, and labile form of zinc and lead. Through principal component analysis (PCA), seasonal influences related to the main sources of metals supply into the reservoir were identified. Metal competition analysis showed that previously added copper affected zinc speciation. However, prior addition of zinc indicated that this metal was complexed by the ligands that were previously available to copper. Nevertheless, no differences were observed in copper speciation. Because the resevoir is subject to intense and frequent cyanobacteria blooms, Cylindrospermopsis raciborskii was isolated from that environment and cultured in the laboratory to obtain its excreted materials. This excreted material was then separated into three molecular weight fractions (> 30 kDa; 30-10 kDa; 10-3 kDa) that were analyzed for complexation capacity (CL e logK ML) with cadmium, copper, lead and zinc, elemental (C, H, N and S) and biochemical composition, fluorescence characteristics and competition for ligands between copper and zinc, and cadmium xvii and lead. The results showed that the fraction >30 kDa and 30-10 kDa had high carbohydrates contents, but low proteins and lipids, whereas for the 10-3 kDa fraction no variation on the biochemical composition was obtained. Fluorescence analysis showed peaks that define proteinaceous materials with 2 5 aromatic rings ususally assigned to be of phytoplankton origin. The CL and logK'ML for the different molecular weight fractions indicated a broad chemical diversity of the ligands that had different affinities for the metals. Metal competition titrations on the excreted material showed that it was only for the >30 kDa fraction that either previously added copper or zinc were complexed by ligands previously available to zinc and copper, respectively. In the 30-10 kDa fraction previously added lead, was complexed by ligands that were available to cadmium. In all fractions no lead complexation capacity was detected when cadmium had been previously added.
Ecologia trófica e ecomorfologia de peixes em um trecho do Alto Rio São Francisco impactado pela transposição do Rio Piumhi, com ênfase nas espécies Pimelodus fur Lütken, 1874 e Leporinus reinhardti Lütken, 1875
(Universidade Federal de São Carlos, 2010-05-28) Stefani, Patrícia Monte; Rocha, Odete; https://lattes.cnpq.br/7577441794992601; https://lattes.cnpq.br/3840139659511108
Studies on the feeding of fishes provide relevant information for understanding the mechanisms allowing the coexistence and exploitation of resources by several species of fishes and also by other components of the aquatic communities.. The objective of the present study was to analyze in detail the feeding habits and the ecomorphology of the fish species Pimelodus fur and Leporinus reinhardti as well as to preliminarily characterize the fedding habits and describe the morphological characteristics of other nine species of fish occurring in a stretch of the Upper São Francisco River Basin. Fishes were sampled in four periods: December 2006 and 2008 (rainy periods) and April 2007 and June 2008 (dry periods) using with gillnets, seine nets and sieve. The results on the feeding ecology of P.fur revealed that this species belong to the trophic gulid of the insectivores, since insects represent between 74.0% and 79.0% of its diet. There were seasonal changes in the diet of P. fur, with food items essentially authochtonous, as aquatic insects larvae being consumed in the dry periods and insects from terrestrial sources, as Araneae and Hymenoptera being added to its diet during the rainy periods, in both São Francisco River and its tributary Piumhi River. In these rivers P. fur displayed high trophic specialization, being a specialist in consuming aquatic insects. It was also observed great overlap in the food items consumed by the different size classes of P. population sampled in both rivers. L. reinhardti had intense feeding activity in both seasons dry and rainy periods. This species belong to the trophic guild of herbivores, being its diet composed mainly by plant material. The feeding spectrum of L. reinhardti is wider in São Francisco River than in the Piumhi River, what can be a consequence of the fact that the gallery forest in the São Francisco River is better preserved in this region than that of the Piumhi River. There were seasonal changes in the diet of L. reinhardt, with some food items as Trichoptera and Hymenoptera only being consumed in the rainy periods. There was no significant change in the diet of L. reinhardti along its development, with preference by plant material in all size classes. L. reinhardti is a feeding specialist with narrow niche breath. There was no feeding niche overlap between P. fur and L. reinhardti in any seasonal period or river stretch studied. Although feeding activity of both P. fur and L. reinhardti was intense during all periods analyzed, the narrow feeding niche breath and the large diet overlap among the size classes within each species population indicate that food sources are abundant in this part of the Upper São Francisco River basin. Regarding the morphological characteristics there was also trophic structuring of the species studied in Piumhi and São Francisco Rivers, with segregation between the body shape of the specialists (insectivores and piscivores) and the more generalist feeders (omnivores and herbivores).
Secagem de pimenta dedo-de-moça (Capsicum baccatum var. pendulum) em secador convectivo horizontal
(Universidade Federal de São Carlos, 2010-05-28) Véras, Antonio Onias Mesquita; Freire, José Teixeira; https://lattes.cnpq.br/2270677706718167; https://lattes.cnpq.br/2122563889901240
The cultivation of pepper is widespread in Brazil since its colonization. This plant, besides being much appreciated in the cuisine has proven pharmacological effects such as lowering cholesterol, inhibiting appetite and the presence of antioxidants such as ascorbic acid and beta-carotene. It is a product whose demand increases every year, but generally still produced handmade diminish the ability of producers to meet the needs of commerce. To contribute to improving the production of pepper dedo-de-moça, it was the behavior of this plant in analyzing the influence of drying process on the nutritional composition and physical qualities of the dried product. For this, drying kinetics were obtained and certain structural properties (apparent density, real density and porosity) as a function of moisture content during drying. Assessing the quality of the final product was performed by quantification of ascorbic acid and study of rehydration. The convective drying and freeze-drying was compared with respect to product quality parameters such as shrinkage, structural properties, vitamin C retention and rehydration characteristics. To describe the kinetics of drying and rehydration were used empirical and semiempirical equations. The characterization of the rehydration process was carried out from the indices that take account of the capacity of water absorption and loss of solutes. The use of seed from the drying of peppers to obtain seedlings was studied by checking the germination through standardized tests. The samples of convective drying at 60 ºC had the best results in terms of nutritional quality, rehydration characteristics and structural properties, comparing with those obtained from freezedrying. In assessing the use of seeds of peppers after processing to obtain new seedlings, the most suitable temperature was 40 oC to cause less damage to germination.
Toxicidade aguda e respostas metabólicas e hematológicas do pacu (Piaractus mesopotamicus, Holmberg, 1887) exposto a concentração sub-letal de triclorfon e recuperação
(Universidade Federal de São Carlos, 2010-05-28) Venturini, Francine Perri; Moraes, Gilberto; https://lattes.cnpq.br/4427903557163246; https://lattes.cnpq.br/7347561381483761
Parasitosis in fishes is a relevant problem in aquaculture. Besides, the organophosphate trichlorfon (2,2,2-trichloro-1-hydroxyethyl phosphonate) is amongst the most used medicine in farming of fishes. Due to trichlorfon use in fish parasitosis control, including pacu (Piaractus mesopotamicus), in brazilian and worldwide aquaculture, it is necessary to study the effects of this organophosphorus compound related to toxicity and metabolic biochemical parameters. The aim of this work was to evaluate trichlorfon acute toxicity (LC(I)50;96h) to P. mesopotamicus and histopathological effects of this exposition; detect metabolic changes in juvenile pacu (P. mesopotamicus) exposed to trichlorfon sub-lethal concentration (10% LC (I) 50;96h); and evaluate metabolic changes after seven and 14 days of recovery. Estimated (LC (I)50;96h) of trichlorfon to alevin was 0.04mg/L; to juvenile fish was 0.07 mgL-1. Histological evaluation showed adaptive alterations, aiming to limit xenobiotic entrance; liver alterations aimed an increase in blood influx, consequently increasing detoxication; kidney alterations indicate excretion increase and skin presented cromatophore migration to superficial folds. After sub-lethal exposure, pacu presented a decrease in hemoglobin, after seven days recovery it was recorded a decrease in MCH and after 14 days recovery analysis showed a decrease in hematocrit. Metabolic alterations observed after sub-lethal expositions and recovery indicated efforts aiming to homeostatic maintenance trough energy production. Brain and muscle AChE activity decreased, regaining the control values after 14 day of recovery in xenobiotic free water.
Perfil dos cursos de formação de professores dos programas de licenciatura em química das instituições públicas de ensino superior da região nordeste do Brasil
(Universidade Federal de São Carlos, 2010-05-28) Marques, Clara Virginia Vieira Carvalho Oliveira; Ferreira, Luiz Henrique; https://lattes.cnpq.br/4819009378941531; https://lattes.cnpq.br/0504326528660511
This study aimed to determine the profile of Chemistry´s courses of Public Institutions of higher education in Brazilian Northeastern, referencing the current educational paradigms and also the legal guidelines regarding processes teacher training governed by the Brazilian education. We attempted to trace the identity of these courses through the perspectives of the adequacy of legal issues and adequacy of the regional reality, understanding the concepts and interactions between faculty and students in the process of training teachers of Chemistry. The methodology was based on the qualitative research structuration, using documentary analysis and content analysis of semi-structured interviews and questionnaires, which were treated under the scheme of the methodology of systemic networks. We studied the Political Pedagogical Project and the Curriculum Matrix for 16 courses in Chemistry from the Northeast, as well as the content analysis of interviews with coordinators and teachers and questionnaires to a graduating students sample. The results showed that the courses are seeking to effect their adequacy, however, was identified a marked segmentation between the training areas of chemical knowledge and pedagogical and still prevailing the model of teacher training based on technical rationality. The Internship and Supervised Practice Component Course as were the dimensions that showed the greatest inconsistencies in the change process suggested by current law. Therefore, the profile of studied courses is not yet equal to that recommended in the new Brazilian education paradigms for teacher training.