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Síntese de zeólita FAU com cristais nanométricos para fins de adsorção
(Universidade Federal de São Carlos, 2014-03-17) Massula, Lívia Maciel; Cardoso, Dilson; https://lattes.cnpq.br/2462847535959232; https://lattes.cnpq.br/4221057085661380
Significant investments have been made in the development of technologies that enable the drying process of natural gas. The molecular sieves are highlighted in this context, due to features such as ion exchange capacity, thermal stability and especially for its ability to selective adsorption. The nanocrystalline structure favors the water diffusion into the pores of the material, providing greater adsorption efficiency. Therefore, the zeolite nano offers attractive possibilities in the exploration of their use in catalytic and adsorption processes. In this context, the present study aimed to vary some parameters such as aging time, the Si/Al ratio and the mineralizing source in order to synthesize nanocrystalline zeolites faujasitas. Diffractogramsshow that the high alkalinity along with increased aging time were effective for the peak intensity reduction. The Scherrer equation confirms that this decrease is due to obtain nanosized crystals. It is observed by SEM that the change of these same parameters also favored particle size reduction. Thermogravimetryresults enable us to find that 30% of the sample weight loss was water, although the adsorption of the sample was not induced. This fact confirms that even at ambient temperature and pressure, the nanocrystalline faujasite is highly hydrophilic. Adsorption isotherms of synthesized samples indicated that the material has a large surface area and a pore volume which favors and benefits its application in water adsorption. The adsorption tests made in situ at the National Synchrotron Light Laboratory (LNLS in Portuguese), XPDanalysis (X-Ray Diffraction Powder), note that its structure remains stable after adsorption and high temperatures, presenting a promising material in drying. Data from X-ray diffraction showed that the decrease of Si/Al ratio in the reaction mixture, both by source of alumina or silica, was not effective to increase the aluminum content in the network and eventually contributed to the emergence of other competing phases with FAU zeolite, thus compromising its purity. These phases also appeared when the alkalinity is increased in the synthesis at a temperature of 100°C (crystallization), where GIS (NaP1) and CAN phaseswere favored. The crystallization temperature reduce to 70°C was enough to solve this problem and show that all samples showed a reduction in the crystallite sizes with increasing external area. 29Si NMR analysis showed that the physicochemical changes done helped to reduce the Si/Al enough to obtain faujasite X. All samples synthesized in this study, regardless of the impurities, showed a reduction in pore volume, even with a rise in external area. The adsorption tests made with CO2, CH2 and N2 have shown that the faujasite has a larger adsorption capacity than commercial zeolite NaA.
Invasão e estabelecimento de Digitonthophagus gazella (Fabricius) (Coleoptera: scarabaeidae) em fragmento de transição cerrado-mata atlântica
(Universidade Federal de São Carlos, 2014-03-17) Angotti, Marina Acero; Flechtmann, Carlos Alberto Hector; https://lattes.cnpq.br/3751581397164912; https://lattes.cnpq.br/2563012255547191
Digitonthophagus gazella is known worldwide because it has been introduced in tropical and subtropical regions of several countries. The aim of this introduction was to assist in the removal of dung pats in pasture areas and to aid in the biological control of flies of veterinary importance. Thus, although D. gazella has a preference for open and sunny habitats and herbaceous vegetation, there is evidence that it apparently has been adapting to closed-canopy areas. Therefore, this study aimed at evaluating the ability of D. gazella to develop in a forest environment. The study was conducted in 2012 and 2013 in the Farm of UNESP - Ilha Solteira in Mato Grosso do Sul, Brazil. To evaluate the presence of D. gazella in the forest were used pitfall traps and to verify its capability of develop in this habitat couples of this species were kept in pasture and forest fragment in the absence and presence of competitors. The results indicate that D. gazella is able to enter the forest fragment, but at short distances from the edge. Additionally, D. gazella was not able to develop and establishment in the forest fragment.
Capacidades dinâmicas a partir da gestão do conhecimento e da aprendizagem organizacional: em busca de desempenhos superiores
(Universidade Federal de São Carlos, 2014-03-17) Gasparini, Liz Vanessa Lupi; Alves Filho, Alceu Gomes; https://lattes.cnpq.br/7885557554922569; https://lattes.cnpq.br/0452113881423529
The area of Strategic Planning seeks to understand how the company creates and maintains competitive advantage, considering factors external and internal constraints. Among these, the lines of thought related to the Resource Based View, the Knowledge Management and Organizational Learning, there are the Dynamic Capabilities, necessary for enterprises to integrate, build and reconfigure internal and external competencies to respond quickly to environmental changes: absorptive capacity related to knowledge; adaptive capacity, organizational learning; and innovation capacity related to innovation and market advantage. Still under development, this recent approach to strategic management is criticized for its weakness in guiding the development and management of capacity and organizational resources. This study proposes that the integration of knowledge management, generating absorptive capacity and organizational learning, generating adaptive capacity, can foster innovation and organizational performance, and can promote indirectly, mediated by innovation, superior organizational performance generated directly, characterizing the generation of innovation capacity; and that if this performance is superior to that of competitors, featuring competitive advantage. This argument has been translated into a model of hypotheses, to contribute to the research model of dynamic capabilities developed by Wang and Ahmed (2007) by detailing how dynamic capabilities can relate and generate differential performance and innovativeness. Results of the questionnaire developed and applied to CEOs of four plants manufacturing Mato Grosso biodiesel, and a national unit of a global corporation in the auto parts industry recognized for its innovativeness and its performance was compared qualitatively to illustrate the model proposed. The results of this study reinforced the proposition and hypotheses examined in a preliminary way. From the viewpoint of view of dynamic capabilities were related the effects of integration of knowledge management and organizational learning in innovation and organizational performance , and indicated how this integration can generate differential organizational performance and innovativeness.
Aplicação de técnicas de CFD no estudo da eficiência de estágio em colunas de destilação para produção de etanol
(Universidade Federal de São Carlos, 2014-03-17) Oliveira, Gladson Cintra de; Gonçalves, José Antônio Silveira; https://lattes.cnpq.br/0337997526924402; https://lattes.cnpq.br/2439230694829140
Distillation is one of the most important and used separation techniques of components at industrial level, applied in a wide range of processes. Its great importance is due to the capacity of purify components of a mixture using the volatility difference among them as driving force. However, this technique represents 40% of the total energy consumption of an industrial facility. Nowadays, with the necessity of rethink the energetic use owing to the massive usage of natural resources, new regulations of pollutant emissions, environmental issues and market competition; the enhancement of the distillation process has become essential to the refineries, petrochemicals and a variety of other sectors of the industry. Empirical studies about the flow dynamics in distillation columns are rare due to the large dimensions of this equipment and the high investment, including measurement instrumentation. This lack of experimental data makes difficult the appropriate understanding of the mechanisms that occur in this equipment, as flow patterns and degree of separation, as well as the relation between both. Nevertheless, to improve the distillation process performance is necessary to deeply know the dynamics of the multiphase flow existing on each tray of the column, where the contact between the phases indeed happens. In this study, was proposed the computational simulation of sieve trays of distillation columns using CFD s tools (Computational Fluid Dynamics). The main aim was to conceive a model capable to predict the hydrodynamics and the more volatile component transfer between the liquid and the vapor. Furthermore, the regions that possibly interfere on obtaining higher efficiencies were pointed out. For that, tridimensional, transient and multiphase models with the Euler- Euler framework were used. The main results show liquid velocity profiles, volumetric fraction, clear liquid height, mass fraction and efficiency. The results presented agreement with the literature. In general, the fluid dynamics results obtained here highlight the significance of the application of models that represent the complex behavior existing on sieve trays, since this crucially influence in the separation degree of the process. The CFD evidenced to be and valuable tool to study this sort of flow on columns internals and can be applied in the design and optimization of those equipment.