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Diagnóstico dos agroecossistemas na microbacia hidrográfica do rio Pirapora - município de Piedade/SP
(Universidade Federal de São Carlos, 2012-08-16) Schneider, Fernando; Costa, Manoel Baltasar Baptista da; https://lattes.cnpq.br/4748534388515487; https://lattes.cnpq.br/0220281286346217
The present work was aimed at making the diagnosis of 25 Agroecosystems located in the Pirapora river micro basin, in the Piedade municipality, State of São Paulo, focusing particularly on the adopted management practices. The socioeconomic, productive and environmental implications of these practices were analyzed and contextualized in the scenario of São Paulo State agriculture. The focus in the watershed, besides their legal aspects, reflects its importance as a geographical until priority actions for integrated management, conservation and natural resource management. In this study we sought to define the indicators that reflect the complexity of management were studied based on the method proposed by MESMIS, as well as by systematic methodological experience Agronomic Institute of Paraná IAPAR, systemic approach. The main results arising from systematized this work were: a significant presence of family farmers in the region, the incompatibility of management techniques adopted in Agroecosystems in relation to environmental and soil characteristics of the region, the weakness in the organization among the farmers, the narrow market for the sale restricted to the middleman, the heavy dependence on external inputs to the system resulting from a conventional farming, the use of pesticides banned, the impairment of water resources and public health of residents for limited use in the preservation of water sources and lack of sanitation. These factors indicate that the diagnosed type of agriculture currently practiced in the region is undermining the sustainability of Agroecosystems due to the degradation of natural resources and, consequently, of their own agricultural activities in the watershed.
Ondas de spin em paredes de domínio unidimensionais em monocamadas magnéticas
(Universidade Federal de São Carlos, 2012-08-16) Caprara, Leandro Peres; Farinas, Paulo Eduardo Fornasari; https://lattes.cnpq.br/0309157540839329; https://lattes.cnpq.br/7222840232739649
Recent investigations on ferromagnetic monolayers predict the existence of spinwave modes without gap in the spectrum, even in the presence of anisotropy. These excitations propagate within the domain walls that exist in the monolayer, hence in quasione- dimensional structures. They are different from the known bulk-modes whose spectrum presents anisotropy gap and whose propagation may cover all the monolayer's extension. Moreover, since they do not have gap in the spectrum, the predicted modes are not associated to an activation temperature and must influence low-temperature observable physical properties. In the present work, a theoretical study is presented for a single ferromagnetic monolayer with domain walls and the response toan oscillating magnetic field. Gapless spin-wave modes' resonances are studied in the results.
Avaliação de modelos de sinterização por fluxo viscoso e determinação da taxa de crescimento de cristais e fração cristalizada em vidros
(Universidade Federal de São Carlos, 2012-08-16) Reis, Raphael Midea Cuccovia Vasconcelos; Zanotto, Edgar Dutra; https://lattes.cnpq.br/1055167132036400; https://lattes.cnpq.br/9034852268717585
Glass-ceramics are materials obtained from the controlled crystallization of glass. The properties of these materials are controlled by the nature and proportions of the crystalline phases and residual glass present. Sintering with concurrent crystallization of glass powders is one of the routes for the development of these materials. One of the few models that describe sinter-crystallization is the Clusters model, which allows one to calculate the density of sintered compacts by knowing composition-dependent properties, such as viscosity (η), crystal growth rate (U) and surface tension (γ), and process-dependent parameters, such as particle size distribution and the density of surface nucleation sites (NS). The determination of input parameters for the model can be labor-intensive, which may difficult its use. In this work a critical assessment of the Clusters model and its bases was performed by checking its predictions against results of sintering of spherical and jagged diopside glass particles. Frenkel s model was capable of describing the initial stages of sintering only qualitatively, requiring an adjusting factor of ~1/3. With this correction, the Modified Clusters model described the powder densification in different conditions well. The effect of crystallization was slightly underestimated by the model, which could be explained by a mechanism of Ns increase in the pores surfaces as observed in a previous work. It has been demonstrated that the jagged particles increasingly round during the heat treatment causing the densification rate to gradually approximate that of spherical particles. Additionally, a model for the determination of crystallized fraction from the surface of particles was derived and can be applied for sintered particles or crystallization DSC studies. A new technique capable of the determination of the crystal growth rate in a temperature range using a single DSC run was developed and successfully tested for three different glasses.
Determinação de molibdênio em plantas combinando microextração e espectrometria de absorção atômica em chama
(Universidade Federal de São Carlos, 2012-08-16) Villamizar, Jenny Andrea Oviedo; Nóbrega, Joaquim de Araújo; https://lattes.cnpq.br/8833989058164529; https://lattes.cnpq.br/5005205399281843
In this study, a procedure for the determination of low concentrations of molybdenum in plants by flame atomic absorption spectrometry (FAAS) was developed. The poor sensitivity of FAAS for determination of refractory elements such as molybdenum, and the typical low levels of this micronutrient in plants require the use of a preliminary preconcentration step. The procedure was based on the solidified floating organic drop microextraction strategy (SFODME). This method was selected based on its simplicity, high enrichment factors and low consumption of organic solvents. Because of SFODME microvolume characteristics, the effect of the discrete introduction of samples in FAAS was studied. The following extraction parameters were evaluated: type and concentration of complexing agent, type of solvent, solvent volume, use of ultrasound or vortex in the extraction process, and effect of discrete nebulization. All parameters were evaluated considering their effects on sensitivity for the determination of molybdenum in plant samples by FAAS. The most critical effects were caused by the type of complexing agent, the use of vortex mixing and discrete nebulization. Prior to the microextraction procedure, Mo complexing conditions were optimized. A 0.5% m v-1 8- hydroxyquinoline solution at pH 4.75 adjusted with acetate buffer and complexing time of 10 min were the ideal experimental conditions. For the microextraction procedure, the highest enhancement factor for Mo was obtained with 60 μL of 1-undecanol and using the vortex mixer for 2 min. Appreciable sensitivity improvements were observed by combining microextraction, the introduction of discrete volumes of sample, and determination of Mo by FAAS. An enrichment factor of 67, limit of detection of 4.9 μg L-1 and limit of quantification of 16.4 μg L-1 were reached. The accuracy of the developed procedure was demonstrated by determining Mo in certified reference materials. Finally, the procedure was applied to samples of roots and leaves of corn.
Caracterização da produção e avaliação de indicadores de qualidade tecnológica de amostras de melado do estado de São Paulo
(Universidade Federal de São Carlos, 2012-08-16) Silva, Mariane Martins Pereira da; Borges, Maria Teresa Mendes Ribeiro; https://lattes.cnpq.br/1800048119205212; https://lattes.cnpq.br/1083005939009933
The molasses, a syrup made from the juice of sugarcane juice, is a sweet liquid, nutritious, homemade and very popular in the Northeast Region of Brazil. It is few explored by small farmers in São Paulo State and, because this, the present study aimed to identify how is the professional involved in its production at São Paulo State through a questionnaire. Whit the returns obtained from the questionnaires and the results of physicochemical analyzes, it can be concluded that few producers know the best way to produce molasses. It s necessary instruction and training for these to be able to exploit this market share.