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Preparação de catalisadores Fe/FER e Fe2O3/FER: avaliação na redução de NO com CO
(Universidade Federal de São Carlos, 2012-08-30) Soares, Magmir Metzker; Urquieta-González, Ernesto Antonio; https://lattes.cnpq.br/3201421189723555; http://lattes.cnpq.br/2389975677904655
Due to the development of society, industrial processes and transportation (cars, buses, trucks, etc.) that emit pollutants are used, which affect the environment and consequently human health, flora and fauna. Among these contaminants, air pollution is the most complex, since it is becoming increasingly difficult to control, despite the efforts of more restrictive laws and the growing number of agencies for its regulation. Among the most worrisome issues stand out nitrogen oxides (NOx) generated throughout the combustion process of hydrocarbons. In the abatement of NOx, various catalytic processes are applied today. However, there is a need for them to be improved and upgraded, as to increase the activity and selectivity of the catalysts used for the conversion of NOx to N2. Thus, the air quality is preserved and the impacts of these contaminants in the environment are minimized. In this context, and considering the recent results in the literature and the Group of Catalysis UFSCar, this study aimed the preparation of catalysts based on cations Fen+ exchanged in zeolite ferrierite (|Nax| [SiyAlwOz]) or based on iron oxide supported and evaluated in the same reduction of NO to N2 by using CO as reducing agent. For purposes of comparison, catalysts were prepared based on commercial zeolites USY-type and mordenite under the same conditions of impregnation. Were also verified the effect of activity in the presence of O2, H2O(v) or SO2. The research included: i) preparation of ferrierite zeolite by ion exchange and impregnation of Mordenite and USY zeolite, ii) characterization via energy dispersive spectrometry of X-rays, atomic absorption spectroscopy, X-ray diffraction, scanning electron microscopy , diffuse reflectance spectroscopy in the ultraviolet visible reduction with H2 temperature-programmed and Mössbauer spectroscopy, iii) evaluating the reduction of NO with CO; iv) evaluation of the catalytic performance fronts interfering O2, H2O(v) and SO2. The catalytic tests showed that the samples with iron content close to 9% (FERtroca80 and FERimpr10) were the most active in the reduction of NO by using CO as reducing agent. The reaction was selective to the formation of desired products, even for high temperatures. The tests indicated that the sample interfering FERimpr10, which was more active in reducing the catalytic activity was not affected by the presence of SO2 or O2, being affected by the presence of O2 and H2O, which promoted a competition for active sites of the catalyst.
Desempenho de filmes soprados multicamada de blendas de polipropileno e copolímeros de etileno
(Universidade Federal de São Carlos, 2012-08-30) Elias, Marcelo Brasil; Canevarolo Júnior, Sebastião Vicente; https://lattes.cnpq.br/4153664441338178
Polypropylene (PP) and polyethylene (PE) are widely used in the flexible packaging market individually as mono or multilayer films. Blending PP and PE in coextruded films has shown limited commercial applications due to the poor adhesion. On this work we made three layer coextruded blown films with ascendant flow and air cooling. The thicknesses were kept constant at 50m, having the external layers made of metallocene ethylene-octene copolymers (m-PE) to provide sealability. The internal layer (structural) was produced with rich blends of polypropylene homopolymer and ethylene-octene copolymers made by metallocene (m-PE and POP) and by Ziegler-Natta (U-PE) catalytic systems. These films were characterized by their mechanical, thermal, optical and morphological properties. Based on the results it is proposed a morphological model of the core layer, in which the matrix phase of PP has a shish kebab crystalline structure, and the disperse phase and the external layers composed by fragmented lamellar crystallites blended with small spherulites. The epitaxial crystallization of the polyethylene copolymer on the shishes of the polypropylene allows good adhesion between the external and internal layers of the multilayered structure. The internal structure formed with the dispersed phase of m-PE and U-PE has shown similar mechanical behavior with better properties at the concentration of 30%.On the other hand, when the dispersed phase of the internal layer is POP elastomer, the Tg and Tm of the matrix PP decrease due the compatibility between the matrix and the dispersed phase, generating shish kebab structures with lower crystallinity. These morphological characteristics guarantee a balanced film regarding the thermomechanical properties, in order to achieve a high performance flexible packaging.
Inserção, atuação e ascensão profissional: o papel do capital social em usinas sucroalcooleiras do interior paulista
(Universidade Federal de São Carlos, 2012-08-30) Zanarotti, Vanessa Regina Cenedezi; Donadone, Julio César; https://lattes.cnpq.br/7643906508178259; https://lattes.cnpq.br/2862944241973678
From the financial logic that changes the investment outlook favoring capital dispersion and fragmentation of control of the business, many industries and businesses have been directly affected by the entry of new capital. In several cases the entry of new capital is not restricted to purely investment of resources, but influence the management of companies, for example, prioritizing the adoption of Corporate Governance as a necessary instrument to regulate the relations among more actors. As a result of these new practices, values, structures and culture are modified starting to integrate new models of standardization of organizational action. Through research conducted in the field in two sugarcane industries, one of family fully control and another of mixed control, aimed from the analysis of the results pertaining to two specific organizational actions: professionalization and dispersion of capital verify the value of the Social Capital in organizational environments surveyed focusing on the importance of this concept in the processes of insertion, performance and career advancement. In the surveyed companies, strong correlations were observed between new organizational processes and revaluation of Social Capital contradicting the initial expectations that the professionalization and dispersion of capital could undermine its importance. Moreover, the concept also showed his productive character in relation to the processes of insertion, performance and career advancement valuing the importance of it in the sugar and alcohol sector. Although the Social Capital is present in both surveyed professional environments, is apprehended differently in the two companies.
Simulação de um alimentador Venturi em trecho ascendente no transporte pneumático de sólidos
(Universidade Federal de São Carlos, 2012-08-30) Padua, Thiago Faggion de; Freire, José Teixeira; https://lattes.cnpq.br/2270677706718167; https://lattes.cnpq.br/8909812973749651
The radial and axial distributions of coarse solids when fed directly in a riser are unknown, despite this type of feeding is very important for drying and preheating of solids during conveying. In this context, this thesis focused on studying the diluted conveying of coarse solids in a riser that was fed by a Venturi feeder in vertical orientation. Experiments were done with particles of 1mm averaged diameter conveyed in a riser (5.32cm of diameter) to obtain the mass loading ratio used in simulations. The assays also made pressure data available to verify the simulations. Eulerian simulations using models based on kinetic granular theory were done. The main goal was to evaluate solids distribution in gas-solid flow for this type of system. The 2D simulations were used to get a stable pattern downstream the feeder after the development length. However, the solid feeding structures generated near feeding percolated the entire riser and, as a consequence, there was no stable pattern. As a consequence, no pattern was found to represent solid phase behavior, since the axial symmetric assumption is invalid for the Venturi feeder. Therefore, only 3D simulations can be used to study asymmetric feeding for the conditions applied, even for a relatively long riser with small diameter. Experimental pressure data was approximately predicted by 3D simulations and prediction was better as the mesh was refined. However, the refined meshes applied in shorter risers to decrease computational effort showed the same solid flow behavior that was seen in the coarser mesh. The 3D simulations showed that there were clusters in the entire experimental riser. Moreover, clusters were generated by solid phase flow near feeding and some of them percolated the entire riser while mixing others. In addition, simulations showed that the bypass region on feeding is in the opposite side from feeding pipe.
Síntese, sinterização em forno de micro-ondas e caracterização da Fe-Ni, PZT e do sistema multifuncional magnetoelétrico PZT/Fe-Ni
(Universidade Federal de São Carlos, 2012-08-30) Muñoz Hoyos, José Rodrigo; Kiminami, Ruth Herta Goldschmidt Aliaga; https://lattes.cnpq.br/7643216999108223; https://lattes.cnpq.br/4742056034033702
The production of multifunctional magnetoelectric materials today is potentiated in the manufacture of particulate (0-3 connectivity) or multilayer (2-2 connectivity) composites comprising a phase with magnetic properties and another with piezoelectric properties. The magnetoelectric response of this type of material depends on factors such as the properties of each of the phases in the composite, the microstructure and the homogeneity of the mixture of phases. The topic of this dissertation is a study of powder synthesis by the Pechini method and of the microwave sintering of ceramic bodies made of magnetic materials such as nickel ferrite and ferroelectric materials such as lead zirconate titanate, as well as an evaluation of their ferromagnetic and ferroelectric properties. This study includes an evaluation of the influence of microwave sintering on the microstructural, ferroelectric and magnetoelectric properties of particulate composites of the PZT/Fe-Ni (80/20) system. To this end, the powders were synthesized by the Pechini method in solutions at different levels of pH in order to evaluate the effect of this parameter on their particle size. The structural and microestructural characterization indicated that crystalline powders of both PZT and Fe-Ni phases were obtained, with nanometric particle sizes which decreased as the pH of synthesis increased. Dense Fe-Ni, PZT and PZT/Fe-Ni ceramic bodies were obtained by microwave and conventional sintering and analyzed by XRD, SEM and EDS. Fe-Ni and PZT samples showing high phase density and integrity were characterized by magnetic and electric hysteresis cycles, which elicited the typical responses of ferroelectric and ferromagnetic materials. The magnetoelectric coupling coefficient of samples of PZT/Fe-Ni composites with densities of >90 % and adequate phase integrity showed a value of 0.7 mV/cmOe for the microwave sintered sample and of 2.2 mV/cmOe for the conventionally sintered sample.