Navegando por Data de Publicação, começando com "2004-07-30"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 5 de 5

Síntese e caracterização de pós de Li2TiSiO5 e Na2TiSiO5
(Universidade Federal de São Carlos, 2004-07-30) Albarici, Viviane Cristina; Leite, Edson Roberto; https://lattes.cnpq.br/1025598529469393
This work presents a systematic study of the synthesis and characterization of Li2TiSiO5 and Na2TiSiO5 compounds. We studied their structural, morphologic and luminescent properties using X ray diffraction, Raman spectroscopy and scanning electron microscopy. These materials have in their crystalline structures centers of pentacoordinated titanium. The samples were produced through two different synthetic routes, both based on Pechini method. Different heat treatments were applied in order to obtain crystalline and disordered materials. The polymeric resins obtained were submitted to Raman spectroscopy, to verify their influence on the different routes used in the powders preparation. These materials were analyzed by X ray diffraction and Raman spectroscopy, to study the thermal evolution of the phases, as well as the structural disorder of the samples. Rietveld refinement were performed on the diffraction patterns of the crystalline samples. The morphology of the samples was investigated by scanning electron microscopy. After structural characterization, luminescent properties of the synthesized powders were studied. These studies were realized using excitation wavelengths of 250 and 488nm. The obtained results showed that Li2TiSiO5 did not present luminescent properties when the excitement wavelength was 250nm but they did when disordered and excited by the 488nm line. On the other hand Na2TiSiO5 samples presented luminescence with excitement of 250nm although didn t present this property when excited with 488nm. For a better understanding of the luminescent properties in the Li2TiSiO5 and Na2TiSiO5 compounds, their electronic structures were investigated by quantum-mechanical studies. This investigation allowed us obtain information about the effects of deformations in the crystalline structure and in the physical properties of these compounds. The obtained results suggest that the luminescent properties can occur by different mechanisms and thus depend on the crystalline structure and the excitement wavelength.
Do "barro de loiça" à "loiça de barro": caracterização etnopedológica de um artesanato camponês no Agreste Paraibano
(Universidade Federal de São Carlos, 2004-07-30) Alves, Ângelo Guiseppe Chaves; Marques, José Geraldo Wanderley; https://lattes.cnpq.br/7962059488333070
Ethnopedological studies have been devoted mainly to agriculture, paying little attention to other aspects (e.g. pottery) of land use. The main objective of this work was to describe and analyse local knowledge and practices among peasant potters, as related to some soils that they use as ceramic resource, in a rural village (Chã da Pia) in Northeast Brazil. Peasant soil knowledge was described and analysed through an adaptation of classic ethnoscientific techniques, attempting to articulate emic and etic data, following Marques s Comprehensive Ethnoecology. Five soil profiles were formally described by researchers (etic approach) near pits where local people obtain pottery clay. Later, peasant artisans where asked to indicate the soil categories or materials they recognized in those same soil profiles (emic approach). Samples collected during both emic and etic approaches were used to describe and analyse the soils existing near these clay sources. Peasant potters recognized variations between the topsoil and subsurface soil. They were capable of distinguishing, identifying and naming, their way, some soil materials arranged in layers ( capas ) along the soil profile: terra (earth), piçarro (gravel), cabeça do barro (clay head), barro de loiça (ceramic clay), and pedra mole (soft rock). The multi-layered arrangement of these materials along the soil profiles was similar to the arrangement of the horizons as described in formal pedology. Nonetheless, local potters did not seem to know about pedogenetic relationships among these layers. Discriminant-canonical analysis, based on chemical, physical and morphological soil features, has shown clear distinctions between the agricultural topsoil and subsurface layers from where ceramic resources may be collected. It also made possible to demonstrate physical, chemical and morphological similarity among some soil materials (as distinguished by local potters) and the pedogenetic horizons where these materials are normally found. Barro de loiça is the main ceramic resource obtained from local soils. It was found mainly as part of the the 2Bt horizon in Eutric Planosols and Haplic Solonetz. The making of ethnopedological studies in different social and pedological environments could be an aid to the advancement of formal soil knowledge, also giving an opportunity to understanding and valuing local soil knowledge and management.
Influência do ambiente construído na distribuição das temperaturas do ar em Araraquara/SP
(Universidade Federal de São Carlos, 2004-07-30) Barbugli, Renata Aboud; Roriz, Maurício; https://lattes.cnpq.br/6355579765506588
The central theme of this dissertation was to evaluate the influence of the urban occupation in the variations of air temperature in Araraquara, a medium size city in the central region of the State of Sao Paulo. At first, temperature takings were made in places that are representative of the different tipologies of urban occupation in the city and the first results showed temperature variations up to 6oC in different places. Besides the measurements made in each of the places, some of the theoretically physical determining parameters of temperature variation were registered, such as: altitude, solar rays incidence angle at noon, roof area, vicinity to water, number of inhabitants per square meter and the percentage of paved, cemented, trees and grass areas. The quantification of the urban occupation design parameters was obtained through topographic maps and serial color orthophotography of the city area. Using the Cluster statistical analysis, the different places were put together according to the similarities of its urban occupation design parameters. Then, for each of the groups, multiple linear regression analyses were made to relate the thermal parameters to the quantified urban occupation parameters. These analyses allowed the elaboration of representative thermal maps of the typical summer and winter days. The observation of the maps showed significant differences between the urban perimeter and the intensely inhabited areas. The least thermal densities were observed in places of higher urban density, demonstrating, then, the occurrence of the urban thermal inertia.
Estrutura genética das populações de abelhas africanizadas (Apis mellifera L.) da Colômbia estimada através de marcadores nucleares e mitocondriais
(Universidade Federal de São Carlos, 2004-07-30) Quiroga, Carlos Fernando Prada; Del Lama, Marco Antonio; https://lattes.cnpq.br/7198095288825585
In 1957 a hybridization process occurred in South America between European and African bees just introduced in the continent. Since the arrival of the Africanized bees to Colombia in 1978 and their total establishment four years later, there have been done few studies about the degree of hybridization between Africanized swarms from Brazil and the resident ones. Allozymic analysis showed that: I) Hk-1 and Mdh-1 allele frequencies in Colombian Apis mellifera samples are very similar to the ones of Brazilian bees; ii) Africanized populations from Colombia have different levels of introgression of African genes into the European genome of the resident bees; iii) these populations are at Hardy-Wienberg equilibrium and the loci are not at linkage disequilibrium, suggesting that the Africanization process of the Colombian bees has been completed probability; iv) the presence of a altitudinal clinal variation suggests an effect of natural selection on Mdh-1 phenotypes. The 16S region of the mitochondrial DNA showed almost exclusively the African pattern of Colombian bees, a result similar to that was found in Brazilian and Uruguayan bees. The increasing frequencies of haplotype A1 (C/A) for the intergenic region CO I CO II of Colombian bees is related to the decrease of the pattern A4 (B/B) during the movement of the Africanized swarms from Brazil to north of the continent. Based on the results for the three regions of the mitochondrial DNA (16S, intergenic region CO I - COII and CO I), a high number of haplotypes was observed, showing the heterogeneous maternal origin of these colonies. These mitochondrial DNA haplotypes are not distributed through a latitudinal or altitudinal clines indicating that the colonies with African mitochondrial DNA is able to explore many different environments in Colombia. Microsatéllite analysis showed the presence of 7 to 12 alleles for the A43 and RJP57-1 loci. The allele sizes varied between 125-150 pb and 400-600pb, respectively. The results of the present work suggest that the bee populations of Colombia are genetically similar to the ones from north Brazil based on the results from nuclear and mitochondrial markers.
Tipos de personalidade e estilos de aprendizagem: proposições para o ensino de engenharia.
(Universidade Federal de São Carlos, 2004-07-30) Kuri, Nidia Pavan; Truzzi, Oswaldo Mário Serra; https://lattes.cnpq.br/5005536921435787
The main purpose of this study is to evaluate how the teaching of engineering can benefit from knowledge of the students personality types and learning styles. To identify the types and styles, two inventories were used, based on Jung s Theory of Psychological Types Keirsey s Temperament Sorter and Felder & Soloman s Index of Learning Styles, both translated into Portuguese. These instruments were submitted to 840 undergraduate students of Engineering enrolled in a five-years regular course at a public education institution located in the interior of the state of São Paulo. The sample was divided into four groups and three subgroups, comprising undergraduate students of Mechanical, Electrical, Civil and Industrial Engineering in their first, third and fifth years, respectively. In the statistical analyses of the results, three approaches were considered: a descriptive analysis, a correlation analysis, and a logistic model. The latter approach was introduced into the statistical analysis of the results in order to verify not only the existence of a correlative structure among the variables analyzed personality types and learning styles but also the probability of the variables qualification and undergraduate year influencing the percentage of responses obtained from the questions of the instruments. The validity of the model was proven in this study. In addition to the statistical analyses, the results were also analyzed qualitatively to discuss the possible effects of the students personality traits on their learning styles and to propose teaching-learning strategies tailored to the profiles identified, aiming to contribute to the teaching practices in engineering. The study have confirmed the reliability and validity of the instruments applied, which have been able to estimate the preferences of the population under investigation. Is also highlighted the fact that the knowledge of the student s personality traits and learning styles may have important implications for teaching. Hence, it may aid the lecturer in different ways, such as: for planning teaching/learning activities, for removing communication barriers in the classroom, for improving personal relationships, and for avoiding productivity losses.