Navegando por Data de Publicação, começando com "2016-03-09"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 4 de 4

Síntese e caracterização de filmes do sistema Zn(1−x)CoxO obtidos por spray pirólise
(Universidade Federal de São Carlos, 2016-03-09) Onofre Ramirez, Yina Julieth; Godoy, Marcio Peron Franco de; https://lattes.cnpq.br/2609654784637427; https://lattes.cnpq.br/2454048514942066
We report a systematic study on the structural, morphological and optical properties of Zn1−xCoxO thin films grown by spray pyrolysis. The employed nominal concentrations were up to 15 Co %. The films were deposited on glass substrates between 220-300 o C using precursors such as zinc acetate and cobalt acetate in aqueous solutions. The effects of Co-doping on structural, morphological and optical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical transmittance and absorbance as well as photoluminescence (PL). The XRD results indicated that all films are polycrystalline with wurtzite crystal structure, a preferential growth direction in c-axis, and no secondary phases. SEM images generally showed uniform surface, and few regions have irregularities due to effects of the inclusion of cobalt as well as substrate deposition temperature. The spectra of transmittance and absorbance exhibited the transitions d-d due to Co2+ ion, a redshift of the absorption-edge and changes in the absorption band intensity with increasing of nominal Co-doping. These observations revealed the substitution of Zn ions Zn2+ and the presence of Co in the state 2+ in tetrahedral coordination in the ZnO lattice. Furthermore, there was a narrowing in band gap of 28 meV by percentage of Co inserted into the lattice. The PL spectra of ZnCoO samples presented three bands associated to near-band-edge absorption (NBE), structural defects and intratomic emissions of Co2+. Their optical emissions were characterized by the presence of traps which capture carriers and affect significantly the emissions. Through a qualitative model in a temperature range we interpreted these traps as potential fluctuations up to 17 meV. We also discussed the annealing in selected samples.
Descentralização da função de compras e licitações: o caso da Universidade Federal de São Carlos (UFSCar)
(Universidade Federal de São Carlos, 2016-03-09) Silva, Rogério Colaço da; Fonseca, Sérgio Azevedo; https://lattes.cnpq.br/2879240108726907; https://lattes.cnpq.br/1015145691788260
The Federal University of São Carlos is part of the current period of expansion of courses and vacancies in the Federal Institutions of Higher Education (IFES), especially after REUNI (Support Program Plan of Restructuring and Expansion of Federal Universities). In order to meet the demand of a growing institution, took effect several administrative changes. One of the changes underway is the implementation of decentralized units of shopping, which is the object of study. This research has the following objectives: identify the factors inherent to this process (steps, difficulties, solutions, benefits, etc.), as well as the impacts of the changes made in the organizational structure generated in the administration of the University, map the new organizational structure Dean of administration (PROAD), identify problems and propose solutions and changes in procedures that may assist in the execution of decentralized purchasing activity. To this end, research is proposed as an action research with qualitative approach with exploratory way, designed as a single case study, the Federal University of São Carlos (UFSCar).
Caracterização ecomorfológica da comunidade de peixes de duas microbacias do Alto Rio Paraná
(Universidade Federal de São Carlos, 2016-03-09) Oliveira, Elisa Martins de; Peret, Alberto Carvalho; https://lattes.cnpq.br/0995579236780271; https://lattes.cnpq.br/3345072251027342
This study examined the ecomorphological pattern ofichthyofauna in two watersheds located on the Upper Paraná River. It was analyzed the ecomorphological variations of species collected from the Beija-Flor stream and Beija-Flor reservoir located in Estação Ecológica de Jataí and Lapa stream located in Área de Proteção Ambiental Corumbataí/Botucatu/Tejubá, to verify interspecific morphological differentiation, the effects oftrophic guilds along the ecomorphological patterns and the effects of water velocity along the ecomorphological standards. Of individuals collected in Estação Ecológica de Jataí, it was selected two Characidium species, on which the ecomorphological variations related to possibility of inter specific morphological differentiation of species of the same genus were analyzed. Considering the common species between the Estação Ecológica de Jataí and the Lapa Stream were observed morphological variables in order to verify the intraspecific morphological differences. Finally these results were related to the meaningof the relation ship between form and function. The main morphological differences found in the individuals of this study were related to the speed of water and feeding habits of the species. The distribution of species in morphological space showed the relation between the ecomorphological attributes and the distribution of species over the water column, where it was possible to characterize the species as demersal, nectobenthicand nektonic species. The relation ship of fish morphology with the water velocity is fundamental. The feeding also contributes with smaller importance in the separation of species in ecomorphological space, but this contribution seems to be because of the presence of these food items is also influenced by the speed of the water. The function of the species in the environmentin which they liveis linked mainly to its trophicniche.
Impactos ambientais da zona rural e urbana na qualidade da água do Ribeirão das Araras
(Universidade Federal de São Carlos, 2016-03-09) Bentos, Adriel Barboza; Borges, Maria Teresa Mendes Ribeiro; https://lattes.cnpq.br/1800048119205212; Stolf, Rubismar; https://lattes.cnpq.br/2436951279203355; https://lattes.cnpq.br/5702789962514874
Agriculture, urbanization and industrialization are some of the human activities that are constantly generating negative impacts on the environment. Much of this degradation directly affects exhaustible lotic systems that are important sources of water supply for the population. This provides the aggravation of problems in obtaining clean water. From this context, the present study aims to assess visual characteristics of habitats in the longitudinal gradient of Araras River and along with the seasonal monitoring of physical and chemical parameters of water quality, state of the natural environment conservation status, while characterizing the changes caused by anthropic activity. For the survey data, 6 points of evaluation were select, ranging from stretches of rural and urban areas. The evaluation took place using the Rapid Assessment Protocol of Habitat Diversity, which at the end of the application, defines the environment preservation level. The monitoring with collection of water samples complied with the climate (drought, intermediate and wet), totaling 13 parameters measured, submitted to analysis of simple variance (ANOVA), using as multiple comparisons test the Tukey test at 5% level of significance. Both, the results of water quality analysis and the PARs analysis showed degradation of shares in the Ribeirão das Araras, as a result of human activities. Regarding seasonality, there was a significant difference only between the parameters: total nitrogen, total phosphorus, chloride, sulfate and electrical conductivity, but without apparent climate relationship. Total phosphorus parameter, except for the 3rd poit, showed values above the limit, established by CONAMA, in the Resolution 357/05, with higher concentrations in the dry season. However, in the 5th point, it was highlighted by having higher concentrations in almost all parameters and also by disagreement in turbidity parameter in the interim period. The protocol described the whole gradient evaluated as amended (48.6 points). The points of greatest environmental criticality were the points 4 and 5, both classified as impacted. Together the tools showed that the points located in the urban area (4 and 5), are the most affected by human activities, mainly because of the margins occupation, channeling, rectification, removal of riparian vegetation, domestic sewage disposal, garbage on the banks, erosion, etc. So, the low-cost of tools adopted here, Ecokit and RAPs, provided to be an efficient way to evaluate the water resources.