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Disertaciones |
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1
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GRAZIELE LOPES DE SOUZA
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Synthesis of alternative oxides for intermediate temperature solid oxide fuel cells
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Líder : RUBENS MARIBONDO DO NASCIMENTO
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MIEMBROS DE LA BANCA :
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RUBENS MARIBONDO DO NASCIMENTO
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ANTONIO EDUARDO MARTINELLI
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RICARDO PEIXOTO SUASSUNA DUTRA
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Data: 30-ene-2017
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Resumen Espectáculo
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La2-xNiO4+d cathode, series materials with structure K2NiF4, have been considered as very promising materials due to their high mixed ionic electronic to intermediate temperature. The interest in these oxides as functional material for cathode increased because of its oxygen permeability and its stability. This material has coefficient of thermal expansion compatible with electrolytes from the La10-x(SiO4)6O2+-d family and apatite structure. These electrolytes have higher conductivities than zirconia-based electrolytes if used in the same temperature range as the above-mentioned cathode. This work reports the synthesis of apatite-type lanthanum silicate powders with nominal composition La10Si6O27 and Lanthanum nickelate (La2NiO4) for using as electrolyte and cathode materials, respectively, in solid oxide fuel cells. The lanthanum silicate was obtained from a co-precipitation chemical route, while the cathode was obtained by the citrate method. The herein proposed synthetic procedure is advantageous in reducing energy consumption and processing time, key elements to decrease the total manufacturing cost. At the end of the syntheses, the precursors powders were characterized by thermogravimetric analysis. The lanthanum silicate powders as prepared were calcined between 500 and 900 °C and characterized X-ray diffraction (XRD), Rietveld refinement and scanning electron microscopy (SEM). Already the lanthanum nickelate was calcined in a single temperature 1200 °C for 4h and characterized by SEM. The structural characterization of the electrolyte indicated the formation of biphasic material after calcination at 900 °C. The effect of sintering temperature, ranging from 1400 to 1450 °C, on the electrical properties was investigated by impedance spectroscopy. Electrical measurements were recorded in the 400 – 800 °C temperature range in air. The lanthanum silicate electrolyte sintered at 1450 °C exhibited total electrical conductivity 2.12 x 10-3 S.cm-1 in 700 °C comparable with samples from literature prepared and sintered at 1500 °C. The electrochemical performance as cathode material was evaluated in a symmetrical cell configuration (cathode/substrate/cathode) using the electrochemical impedance spectroscopy. Lanthanum nickelate cathodes obtained by screen printing and sintered at 1300 ° C for 4 h had an area specific resistance (ASR) of 2.85 ohm.cm2 at 800 ° C under an oxygen atmosphere. Lanthanum nickelate was mixed with the electrolyte material and sintered at the same temperature used for sintering of the cathode film, in order to evaluate possible chemical reactions between them and characterized by X-ray diffraction and SEM. The materials showed good electrochemical results compared to the literature and chemical stability up to 1300 ° C.
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2
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THATIANA CRISTINA PEREIRA DE MACEDO
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PROCESSING AND CHARACTERIZATION OF POLY (METHYL METHACRYLATE) (PMMA) WITH ELASTOMIC PARTICLES AND POLYCARBONATE (PC) BLEND
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Líder : EDSON NORIYUKI ITO
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MIEMBROS DE LA BANCA :
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EDSON NORIYUKI ITO
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ROSANGELA DE CARVALHO BALABAN
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MARCELO MASSAYOSHI UEKI
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Data: 13-feb-2017
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Resumen Espectáculo
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The aim of this work was to study the rheological, mechanical and microstructural behavior of poly (methyl methacrylate) / polycarbonate (PMMA/PC) blends using a PMMA with elastomeric particles until phase inversion. The PMMA/PC blends were processed in single screw extruder and co-rotational twin screw extruder, with subsequent injection molding. The changes in the physical and chemical characteristics of the polycarbonate were analyzed by viscosimetry and by Fourier transform infrared spectroscopy (FTIR) before and after processing. The mechanical characterizations were performed by uniaxial tensile test and Izod impact. The rheological tests were done by melt flow index (MFI) and capillary rheometry. Microstructural analysis of the polymer blends was performed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The thermal degradation temperature was determined by thermogravimetric analysis (TGA). The results of the MFI in the processing conditions indicated a higher flowability of the polycarbonate among all the studied compositions, most of them present higher value of MFI for the materials processed in twin screw extruder. In the capillary rheometry of the unprocessed materials a lower PC viscosity variation was observed as a function of the shear rate increase, but the processing of this material caused significant changes in the rheological curves. TGA showed a higher degradation onset temperature for the PC, but the processing altered the thermal stability of that polymer more than for poly (methyl methacrylate). The intrinsic viscosity measurements of the polycarbonate indicated a possible degradation by chain scission after processing due to the decrease in the molar mass of the material. The FTIR did not identify distinct bands for the PC before and after the processing. The mechanical characterization by uniaxial tensile revealed higher tensile strength, higher modulus of elasticity and greater elongation at break for polycarbonate, and the compatibility of PMMA/PC blends varied with PC concentration, with some compositions that showed synergism in the properties. Izod impact strength showed a high PC impact strength when compared to PMMA, but the addition of 20 wt% of PC in the PMMA matrix significantly increased the impact strength of PMMA/PC blends. The morphological analysis by AFM visualized the presence of spherical elastomeric particles with an average size of about 182 ± 20 nm in the PMMA, evenly distributed along its microstructure, while the PC presented only one homogeneous phase. The PMMA/PC blend showed two well-defined phases throughout all the compositions, and showed evidence of morphology with co-continuity characteristics for the compositions between 70/30 and 50/50 wt%, both for the materials processed in songle screw extruders as well as twin screw extruders. The compositions with the highest percentage of PMMA in the PMMA/PC blends were the ones with the best results of rupture strength and elongation at break, and the Izod impact resistance showed intermediate properties. The results in the phase inversion followed the characteristics of the polycarbonate, not showing significant gains of properties. It was concluded that the use of PMMA with elastomeric particles as the matrix phase in the PMMA/PC blend enhanced the applicability of the material.
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3
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MARIANA CHIANCA LÚCIO DA SILVA
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STUDY THE EFFECT OF ALUMINA IN THE WC-Al2O3 SYSTEM BY POWDER METALLURGY
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Líder : UILAME UMBELINO GOMES
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MIEMBROS DE LA BANCA :
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ARIADNE DE SOUZA SILVA
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LEILIANE ALVES DE OLIVEIRA
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UILAME UMBELINO GOMES
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Data: 16-feb-2017
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Resumen Espectáculo
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Tungsten Carbide (WC) is best known for its excellent physical and mechanical properties. However, it has limitations, mainly when the tougher and lighter material is requested. An alternative to minimize these problems is a composite of WC and alumina (Al2O3) to reducing density and promoting toughness at certain temperatures. Thus, in this work, the effects of the different amount of alumina and powder metallurgy processing parameters on microstructure of particulate and sintered composite (WC-Al2O3) were studied and the mechanical properties, particularly the microhardness, of the product were analyzed to find an alternative cutting tool material. In the study, the particulate materials production route was applied. The composite powders have the following compositions: WC with 5, 10 and 15wt% of Al2O3 processed by high energy milling in a planetary milling for 1, 4 and 10 hours. Compacting of mixed powders was done using a uniaxial press in a cylindrical die of 5 mm diameter under a pressure of 400 MPa. Solid phase sintering was performed in a resistance furnace at 1450 and 1550 °C with 1 hour of holding time and heating rate of 10°C/min in argon atmosphere. The raw materials were characterized by particulometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The milled powders and sintered samples were subjected to the same tests and microhardness test was also done for sintered samples as well. The results showed that high energy milling met the targets for particle size and dispersion of composite components. However, due to partial sintering or consolidation of green compact, the microhardness did not achieve to significant results and microstructures with high porosity were observed.
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4
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JOSÉ RAELSON PEREIRA DE SOUZA
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EFFECT OF SINTERING AND HIGH-ENERGY MILLING ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ALUMINUM ALLOYS RECYCLED FROM BEVERAGE CANS
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Líder : MAURÍCIO MHIRDAUI PERES
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MIEMBROS DE LA BANCA :
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MAURÍCIO MHIRDAUI PERES
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RUBENS MARIBONDO DO NASCIMENTO
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BRUNO BELLINI MEDEIROS
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Data: 24-feb-2017
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Resumen Espectáculo
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This work presents the study of the obtaining and characterization of aluminum recycling from beverage cans composed of aluminum alloys AA3004, 5042 and 5182, through the technique of high energy milling and powder metallurgy. The cans were selected, drilled and milled to obtain the metallic powder under different milling times (1h, 1h30min and 2h). The obtained powder was compacted at a load of 400 MPa and sintered at 600 ° C for two hours. For characterization of the aluminum poder were realized XRD, SEM and EDS, and laser granulometry analyzes; while the material consolidated by sintering, in addition to the analyzes via DRX, SEM and EDS, was also characterized by dilatometry, compression and microhardness Vickers tests. The size of the particles and their relationship to the properties of the aluminum alloy were evaluated. The processing route adopted resulted in the effective compaction of the aluminum powder from the beverage can milling, but with a clear presence of porosity, typical of sintered metals. A large incidence of precipitates of the dispense Al6Mn phase in the Al-alpha matrix (CFC) was observed. The samples presented variations in their mechanical properties as a function of milling time. The compressive strength increased from 105 N / mm² with 1h grinding to 120 N / mm² with 1h30min and decreasing to 110N / mm² with 2h grinding, but the ductility presented little variation. The hardness was 56.43 HV, 66.52 HV and 92.21 HV for the times of 1h, 1h30min and 2h, respectively.
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5
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RAYANE RICARDO DA SILVA
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Analysis of the synthesis parameters of NbN via gas-solid reaction.
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Líder : CARLSON PEREIRA DE SOUZA
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MIEMBROS DE LA BANCA :
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CARLSON PEREIRA DE SOUZA
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ANDRE LUIS LOPES MORIYAMA
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ANDARAIR GOMES DOS SANTOS
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Data: 02-mar-2017
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Resumen Espectáculo
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The aim of this work is to study the synthesis of Niobium Nitride, starting from the precursor tris (oxalate) oxiniobilato ammonium hydrate, through the gas-solid reaction in a fixed-bed reactor. The heat treatment conditions to obtain the NbN were at temperatures 700, 800, 900, 1000 and 1100°C varying the time in the isotherm between 3, 4 and 5 hours. The gas mixture is composed of nitrogen and hydrogen. The composition and the total flow of the gas flow were varied. The obtained materials were characterized by X-ray diffraction (XRD), Rietveld Refinement and Scanning Electron Microscopy (SEM). Increasing the reaction temperature and time in the isotherm it was observed the phase change of niobium oxide to niobium nitride. There was formation of two phases of nitride, and the hexagonal phase is present in greater quantity, and the tetragonal phase in less quantity. These results are not observed in the literature.
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6
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CAROLINE SUZY DO NASCIMENTO GARCIA
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STARCH LAURATE OBTAINED FROM STARCH EXTRACTED THE SEED OF MANGA TOMMY ATKINS: SYNTHESIS, CHARACTERIZATION AND APPLICATION IN NON-AQUEOUS DRILLING FLUIDS.
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Líder : EDSON NORIYUKI ITO
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MIEMBROS DE LA BANCA :
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EDSON NORIYUKI ITO
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ROSANGELA DE CARVALHO BALABAN
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MARCOS ANTONIO VILLETTI
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NÍVIA DO NASCIMENTO MARQUES
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Data: 03-mar-2017
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Resumen Espectáculo
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After processing of mango in pulp and juices industries, tons of residues such as shell and seed are discarded without proper use. About 15% to 20% of the weight of the mango, depending on its variety, is due to the seed, from which it is possible to obtain the starch. In order to add value to this residue, this study aimed to produce an ester from mango starch (Tommy Atkins), through the transesterification reaction of vinyl laurate (LV) with starch. The synthesis was performed in the presence of a basic catalyst (K2CO3) in dimethyl sulfoxide (DMSO) at 110 ° C and N2(g). The product was purified by precipitation in methanol and characterized by Fourier Transform Infrared Spectroscopy (FTIR), thermal gravimetric analysis (TGA), solubility tests and scanning electron microscopy (SEM). FTIR confirmed the starch laurate was obtained, by displacing the C=O band from the vinyl ester at 1759 cm-1, to 1743 cm-1 in vinyl laurate, due to satured ester in the modified starch. 1H NMR indicated that the starch laurate showed a degree of chemical modification at 1.13 and 13C NMR showed a signal at 173 ppm, which can be attributed to the carbonyl of the starch laurate. Thermogravimetric analysis showed that the modified starch has higher thermal stability than its precursors and than a physical blend of starch and vinyl laurate. Solubility tests also confirmed the chemical modification, since, unlike the starch, the product was soluble in toluene and chloroform, and remained insoluble in water and DMSO. SEM data showed that crystalline domains on starch were broken after chemical modification and the appearance shown in micrograph is unstructured (amorphous). From the hydrophobic starch product obtained the present work sought the use of this starch in petroleum well drilling fluids based on invert emulsion (W/ O), due to the high interest in developing non-aqueous fluids of low toxicity and high performance under very high temperature and pressure conditions. The physical-chemical experimental results of the studied fluids indicate that the obtained product of the synthesis presented similar performance to the fluid with commercial additive in the control of the filtrate.
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7
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CICERO LEONARDO PEREIRA DE SOUZA
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An investigation of the influence of heat imput and adittion of Al and PVC films on the microstructure of the welded metal deposited by basic coated electrodes E7018
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Líder : AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MIEMBROS DE LA BANCA :
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AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MOACIR BISPO RAMOS
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NICOLAU APOENA CASTRO
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RUBENS MARIBONDO DO NASCIMENTO
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Data: 10-mar-2017
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Resumen Espectáculo
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The shield metal arc welding (SMAW) is one of the oldest welding processes and the first one to be used in large industrial scale. During the XX century the SMAW was the most applied process for metal joining, remaining until nowadays as one of the most used in the Brazilian market. In this kind of welding one of the biggest problems is to avoid the hydrogen induced cold cracking, what imposes rigid requirements in the storing of the weld consumables. In order to avoid the humidity absorption, the consumables must be dried out in special ovens at temperatures in the order of 450 C, what implies in additional and higher manufacturing costs. In this context a recent research suggested modifications in coating of electrodes providing an alternative for execution of welding with low hydrogen electrode AWS E7018 without having to dry it, The welds were developed with basic coated electrodes (hygroscopic) externally painted with aluminum spray paint for high temperatures or wrapped with thin plastic films (PVC) and aluminum foil films. The induced metallurgical changes in the deposited metal, associated with the addition of new materials to the electrode coating, were investigated, wereby the microconstituents in the fusion zone were quantified using a software for image analysis. In the actual work, with the use of a field emission microscope, MEV-FEG, high contrast images could be obtained, this allowed a detailed characterization of the various microconstituents and a more precise description of their morphology. In special it was possible to evaluate the influence of the protective films in the grain size and aspect ratio of the microconstituent AF (acicular ferrite). On base of a literature review a critical analysis is presented, that embraces the effect of the more relevant parameters on the final microstructure and resulting mechanical properties. The results showed that for higher values of heat input the microstructure, especially the acicular ferrite, tends to be coarser. With the use of PVC coatings and aluminum paint, a slight reduction was achieved in this granulometry, since the microstructure was more refined than with reference electrodes (E7018 pure and BRH4R).
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8
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FÁBIO GUSTAVO LIMA PEREIRA
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Fadigue and fracture of the nickel base superalloy, inconel 625, submited cyclic stress R = -1
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Líder : RUBENS MARIBONDO DO NASCIMENTO
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MIEMBROS DE LA BANCA :
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JORGE MAGNER LOURENÇO
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JOSÉ DE ANCHIETA LIMA
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NICOLAU APOENA CASTRO
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RUBENS MARIBONDO DO NASCIMENTO
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Data: 17-mar-2017
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Resumen Espectáculo
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The fatigue process in materials is the failure mechanism with the presence of cyclic stresses. Surface flaws and stress concentrators may lead to nucleation of cracks during this process. The cracks propagate and cause component fracture after a sufficient number of cycles. This failure mechanism has become increasingly important as soon as the technological progress has enabled the implementation of a larger number of structures subjected to different modes of loading and vibrations such as the equipment used in the pre-salt industry. New materials are being developed especially for this sector and they have to meet some specifications to work on this harsh environments. Examples of materials used under such circumstances are the resistant nickel-based alloys. In this context, this study aims to evaluate the behaviour of the Nickel-based superalloy, Inconel 625, under load with load ratio R equal to -1 as well as its mechanical and microstructural properties. The mechanical, microstructural and morphological characterization of Inconel was analyzed by axial fatigue, tensile, hardness, optical microscopy, SEM and XRD tests. The results indicated that Inconel 625 is able to associate high mechanical strength and moderate hardness with good ductility. The diffractometry allowed to verify the presence of a matrix phase 𝛾 and carbides of the types 𝐶𝑟23𝐶6, MoC e NbC. The development of the S-N curve made it possible to estimate the fatigue strength of the material to be approximately 255 MPa. The fracture surfaces were observed by scanning electron microscopy, in order to investigate the effects produced by fatigue cracks. The presence of beach marks and fatigue striations were observed, they are typical characteristics of the fatigue process.
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9
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ANA CAROLINA MARÇAL PIRES FERREIRA LUCAS
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Diagnosis of a petroleum derivative contamination in soil and groundwater in a Waterway Terminal: a case study in the city of Natal-RN.
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Líder : MARCUS ANTONIO DE FREITAS MELO
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MIEMBROS DE LA BANCA :
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CARINA GABRIELA DE MELO E MELO BARBOSA
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DJALMA RIBEIRO DA SILVA
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MARCUS ANTONIO DE FREITAS MELO
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Data: 31-mar-2017
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Resumen Espectáculo
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The Aquaviários Terminal Unit's main function is to receive, store and distribute oil, oil products and liquid renewable fuels, ensuring the supply of domestic and international markets. The great logistic movement generated by the exploration, processing, storage, transportation and commercialization of oil and its derivatives has generated worries related to its potential contamination of the environment. Because of the numerous accidents with fuel spills, which cause contamination of soils and waters by oil-derived hydrocarbons, research in this context makes it a challenge for professionals working in the area, due to the complexity of interactions occurring in the soil and in the water. The Terminal, object of study, is located in the city of Natal-RN and occupies an area of 110,000 m2. The aim of this study is to evaluate soil and groundwater contamination by petroleum by-products in the 1430-04 basin, characterizing the presence of substances with potential contamination in soil and groundwater through the collection of soil and water samples for the analysis of TPH fractional parameters, BTEX, VOC, SVOC and metals. As well as the analysis of soil physical parameters (particle size, total and effective porosity, particle density and total soil, natural moisture) and organic carbon fraction. The chemical analyzes of soil samples did not present concentrations of the analyzed parameters (TPH, BTEX, VOC, SVOC and metals). Concentrations of benzene were detected in the groundwater samples, in addition to xylenes and TPH. For metals, concentrations of lead were detected in addition to iron. For dissolved metals, only lead had concentrations above the values investigated. All results of the chemical analyzes were compared with the values of CONAMA Resolution 420/2009.
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10
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ÉRICK STÉFANO SILVEIRA GUERRA
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Study of the addition of poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) thermoplastic to epoxy resin for use in self-healing composites
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Líder : ANA PAULA CYSNE BARBOSA
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MIEMBROS DE LA BANCA :
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ANA PAULA CYSNE BARBOSA
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EVANS PAIVA DA COSTA FERREIRA
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JOSE DANIEL DINIZ MELO
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MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
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MARIA ODILA HILÁRIO CIOFFI
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Data: 28-abr-2017
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Resumen Espectáculo
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Repair of damaged composite structural elements to restore pristine conditions and meet regulatory requirements can be a great challenge. Thus, materials capable of self-healing when damaged are of great interest. In one of the self-healing approaches studied in the literature, thermoplastic is added to a thermosetting matrix and the damaged material partially recovers its mechanical properties after a healing cycle. This technique employs heat to partially re-establish the mechanical properties of the composite material. In the present study, modification of epoxy resin with poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (E-MA-GMA) termoplastic was evaluated. The influence of the employed type of hardener (anhydride and amine) on the properties of the material was also investigated. Dynamic mechanical analysis (DMA) was performed to evaluate changes in viscoelastic properties due to the thermoplastic addition. Fourier transform infrared (FTIR) spectroscopy was used to evaluate chemical alterations in thermoplastic-epoxy systems. Atomic force microscopy (AFM) was employed to examine the role of thermoplastic addition on epoxy network structure. Healing ability was assessed by comparing areas damaged by standard indentations on the surface of samples before and after healing cycle for materials with and without E-MA-GMA addition. Results suggest the presence of a E-MA-GMA second phase after curing, an increase in glass transition temperature (Tg) for all thermoplastic blended samples as compared to neat epoxy, the presence of one single Tg for epoxy anhydride hardened E-MA-GMA mixtures and chemical and structural alterations on epoxy network due to addition of E-MA-GMA. Further, the disappearance damage caused by indents on areas of the material modified with thermoplastic after a heating cycle supports the potential use of E-MA-GMA as healing agent.
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11
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NIVALDO FREIRE DE ANDRADE NETO
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STUDY OF THE PHOTOCATALITICAL AND ANTIMICROBIAL ACTIVITIES OF AGCl PARTICLES IMPREGNATED WITH WHAT IS OBTAINED BY SONOQUÍMICA SYNTHESIS
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Líder : FABIANA VILLELA DA MOTTA
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MIEMBROS DE LA BANCA :
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FABIANA VILLELA DA MOTTA
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MAURICIO ROBERTO BOMIO DELMONTE
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KATIA NICOLAU MATSUI
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BRAULIO SILVA BARROS
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Data: 16-jun-2017
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Resumen Espectáculo
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The growth of industrial activities led to an increase in the generation of effluents, which led environmental agencies to propose the creation of regulatory frameworks to limit the generation of effluents. The effluents generated by the textile industries are difficult to be degraded by traditional methods of treatment. Advanced oxidative processes (POAs) are an efficient alternative for the degradation of organic pollutants such as dyes (methylene blue). In this work, silver chloride particles (AgCl) impregnated with copper oxide (CuO) were synthesized via sonochemistry. AgCl/CuO 1:1 and 2:1 compositions, respectively, were prepared. Such compositions went through three distinct procurement routes. To characterize the particles, X-ray diffraction (XRD), scanning electron microscopy with field emission (SEM-FEG), and UV-visible (UV-vis) spectroscopy were performed. To verify the applicability of the compound were carried out in the samples of AgCl/CuO photocatalytic tests for degradation of the methylene blue dye and the antimicrobial activity against the bacteria Escherichia coli and Staphylococcus aureus. The results of X-ray diffraction confirmed the formation of AgCl and CuO in all samples, with no evidence of doping for any route used. The results of the photocatalytic activity indicate that increasing the ratio of AgCl (1:1 to 2:1) accelerates the degradation of methylene blue on average by 25%.
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12
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THIAGO SOUZA VIANA
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INFLUENCE OF THERMAL HEAT TREATMENTS IN THE MICROSTRUCTURE OF A PSEUDOPLASTIC NiTi LEVEL.
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Líder : AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MIEMBROS DE LA BANCA :
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AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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NICOLAU APOENA CASTRO
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RUBENS MARIBONDO DO NASCIMENTO
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WALMAM BENÍCIO DE CASTRO
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Data: 30-jun-2017
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Resumen Espectáculo
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In the present work, the influence of heat treatments on the microstructural transformations of an approximately equiatomic NiTi memory form alloy was investigated. A NiTi wire with 2.5 mm in diameter, received in the work hardened state, was submitted to annealing heat treatments at 450°C and 500°C in order to verify the calorimetric and microstructural changes. Optical and electronic microscopy and X-rays diffraction were employed to characterize the structure and the phases morphology. The analysis via differential scanning calorimetry allowed the determination of the transition temperatures (As, Af, Ms, Mf) and the change in the transformation temperatures between the as received worked hardened and annealed material is discussed. The microstructure in the work hardened condition and after the annealing heat treatments was analyzed in detail via field emission scanning electronic microscopy (MEV-FEG), which showed a coarsening of the martensite plates for higher temperatures and longer heat treatment times. Microhardness measurements did not reveal any significant influence of the annealing or subzero heat treatments on the mechanical behavior of the alloy.
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13
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AMANDA REGINA DE SOUZA MACEDO
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OBTAINING AND CHARACTERIZING A DIATROMETRIC DIATOMIC TAPE THROUGH THE TAPE CASTING PROCESS
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Líder : UILAME UMBELINO GOMES
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MIEMBROS DE LA BANCA :
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ARIADNE DE SOUZA SILVA
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CARLSON PEREIRA DE SOUZA
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LEILIANE ALVES DE OLIVEIRA
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UILAME UMBELINO GOMES
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Data: 31-jul-2017
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Resumen Espectáculo
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Diatomitehas a widevarietyofapplicationsdueto its physicalandchemicalpropertiesandiswidelyused as a filter material becauseof its high porosity. It is a material thatalsohasdielectricpropertieswhenin its naturalstate. In thiswork, a ceramic tape producedfromthediatomitewasstudiedthroughthe tape castingprocess, tobeapplied as in dielectriccapacitors. The raw material (diatomite) wascharacterizedbyparticulometry, X-raydiffraction (XRD), X-rayfluorescence (FRX), scanningelectronmicroscopy (SEM) and Fourier transforminfraredspectroscopy (FTIR) ). The ceramic tape wasobtainedbypreparing a slipwithdiatomitepowder, solvent, dispersant, binder, plasticizeranddefoamer; The mixingofthematerialswascarried out in a ballmill. The rheologytestwasperformedtoevaluatetheviscosityofthesuspension. The slipwasgluedonto a filmandafter 24 hours thegreenribbonwasremoved, whichwascharacterizedbydifferentialthermalandthermogravimetricanalysis (ATD \ ATG), DRX, FRX and MEV. A dielectricceramic capacitor (prototype) wasbuiltwiththegreen tape, in whichtheelectricalcapacitanceandresistancemeasurementswereperformed, andthedielectricconstantofthe material (diatomite tape) wasobtained. The green tape underwent a heattreatment for theremovaloforganicsat a temperatureof 600 ° C and a heating rate of 0.5 ° C / min. The sinteringwasperformedatthreedifferenttemperatures (1000 ° C, 1150 ° C and 1250 ° C), with a heating rate of 5 ° C / min. And 60 min isotherm. It wasthencharacterizedby XRD, SEM, anddensityandporositymeasurements. It wasobservedthatthesinteredsamplespresented high porosity in theirmicrostructure, however, for thehighersinteringtemperatures, therewas a reductionofthisporosity. The diatomitemorphologywasmaintained for thegreenandsinteredbands, showingits navicularand tubular shape. The presenceof pores isdueto a typicalcharacteristicofthefeedstock (diatomite) used, as well as totheprocessingparameters, whichsignificantlyinfluencedthedielectricpropertiesofthe material, particularlygreen tape.
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14
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EDUARDO RODRIGUES DA SILVA
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EFFECT OF HEAT INPUT IN THE MICROSTRUCTURE OF WELD BEADS DEPOSITED WITH E81T1-Ni1C TUBULAR WIRE IN 3 VARIANTS OF API X-65 STEELS
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Líder : AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MIEMBROS DE LA BANCA :
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AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MAURÍCIO MHIRDAUI PERES
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NICOLAU APOENA CASTRO
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CELINA LEAL MENDES DA SILVA
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Data: 23-ago-2017
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Resumen Espectáculo
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The objective of the present work is the microstructural characterization of weld beads deposited with E81T1-Ni1C tubular wire in 3 variants of X65 API steels. These are alternative materials used in the assembly of pipelines for the transportation of oil and gas, where the qualification of the welding procedures is a prerequisite for guaranteeing the mechanical properties of the component in service. In this context, the detailed characterization of the microconstituents that compose the three sub-regions of the weld is an essential tool, since it contributes with important elements to the understanding of the correlation between process variables and the final properties of the fabricated assembly.
For this research weld beads were deposited under controlled conditions by the FCAW process, which allowed thermal inputs of 7.3; 11.3 and 22.1 KJ / cm corresponding to cooling times (Δt 8/5) estimated at 3.5; 6.5 and 20s. The microstructural characterization was made by optical microscopy and scanning electron microscopy with Field Emission Gun, where the high quality of the contrast in the images allows the identification and more detailed classification of the microconstituents present. The results for the welding deposits with medium thermal input and Δt 8/5 = 6.5 s, showed that the fused zone (ZF) of the three alloys is predominantly formed by the microconstituint acicular ferrite (AF), with average hardness of the order of 240 HV0,3, aspects that according to the literature are requirements of excellent toughness. When welded with low thermal input, the ZF had AF and average hardness of 260 HV0.3 and Δt 8/5 = 3.5 s. The high thermal input provided a hardness lower than 200 HV0.3 and AF formation in the ZF, and greater Δt 8/5 of approximately 20s. The area affected by the coarse grain heat (ZAC-GG) showed for the 3 steels microstructure basically formed by second phase ferrite (FS) and small fraction of primary ferrite. According to the microhardness profile along the sub-regions of the weld, the maximum peaks located in the ZAC-GG are lower than 340 HV for the bead made with medium heat input, which is indicative of absence of martensite and good toughness for this critical region of the heat affected zone. A hardness profile made in ZAC-GG, with values higher than 350 HV0,3, indicates the risk of formation of martensite in the three alloys of API X65 welded steel with low thermal input.
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15
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JULIANO AUGUSTO MEDEIROS DE MENEZES E OLIVEIRA
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Microstructural Characterization of Eutectic Aluminum Alloys in the As-Cast State and Heat Treated by Homogenization
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Líder : MAURÍCIO MHIRDAUI PERES
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MIEMBROS DE LA BANCA :
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MAURÍCIO MHIRDAUI PERES
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RUBENS MARIBONDO DO NASCIMENTO
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WANDERSON SANTANA DA SILVA
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Data: 25-ago-2017
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Resumen Espectáculo
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The aluminum alloys in the eutectic composition have a characteristic low melting temperature and a complex microstructure formed by eutectic constituents. They can be applied in the foundry industry, as they additionally present high fluidity and low tendency to the formation of porosity and hot cracking. The Al-Cu (binary), Al-Cu-Si and Al-Cu-Mg (ternary) and Al-Cu-Si-Mg (quaternary) systems were produced by sand casting. The alloys were analyzed microstructurally in the as-cast condition and after homogenizing heat treatment at 495 ° C for until 24 hours, via x-rays fluorescence (FRX), x-rays diffraction (XRD) and scanning electron microscopy (SEM) with dispersive scanning energy system (EDS). The results showed the formation of the main constituent phases in the thermodynamic equilibrium state, the significant formation of eutectic constituents and the formation of a small amount of intermetallic Al5FeSi (platelets) and AlFeSiMgCu (chinese writing), commonly found due to the intrinsic presence of iron as an impurity In aluminum alloys.
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16
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LUANA BARBOSA DA CRUZ CAVALCANTI
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Production of NiO/CDG ceramic tapes by Tape Casting
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Líder : WILSON ACCHAR
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MIEMBROS DE LA BANCA :
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WILSON ACCHAR
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Ana Paula da Silva Peres
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Antonio Carlos Silva da Costa
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LUCIANNA DA GAMA FERNANDES VIEIRA
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SHEYLA KAROLINA JUSTINO MARQUES
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Data: 08-sep-2017
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Resumen Espectáculo
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Solid oxide fuel cells (SOFCs) are electrochemical devices that are increasingly used because they have high energy conversion capacity and are minimally polluting. Several materials are used in the composition of the anode, among them NiO / CDG, since they promote an increase of intragranular ionic conductivity, improving the properties of the fuel cell, besides minimizing production costs, since there is a decrease in the operating temperature of SOFCs. One of the most widespread fine-film production techniques today is Tape Casting, which has been widely used in the electronics industry in capacitors, ferromagnetic memories, ceramic circuit substrates, among other applications, thanks to the great versatility of this method. This process requires a slurry homogeneous and stable slip, which composition of the formula can be varied according to the powder used. In this work, NiO/CDG slurries were prepared in aqueous medium, with the addition of polymers responsible for stability, flexibility and resistance to the body in green. The characterization was performed from the study of the stability of the suspension through rheological analysis, which showed a pseudoplastic behavior, in which there is a decrease of the viscosity as the shear rate increases. Studies were performed to verify the apparent density and porosity of the sintered bodies, X-ray diffraction, Differential Thermal Analysis (DTA), Thermogravimetric (TGA) and mechanical resistance. The XRD results allowed to observe the phases present in the tapes produced after the sintering stages at temperatures of 1250oC, 1300oC and 1400oC. The thermal analysis tests demonstrated the stability of the samples from 450oC, the mechanical strength tests showed a good flexural strength between 80 and 90 MPa for multilayer tape and 10 MPa for single tapes, allowing to observe that there is a better performance in tapes with multilayers, as there is an increase in mechanical resistance. The tapes produced were porous, dense and resistant.
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17
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ALLANA AZEVEDO DO NASCIMENTO
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Addition of poly (ethylene-co-acid-methacrylic) (EMAA) as a self-repair agent in carbon-epoxy composites
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Líder : ANA PAULA CYSNE BARBOSA
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MIEMBROS DE LA BANCA :
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ANA PAULA CYSNE BARBOSA
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EVANS PAIVA DA COSTA FERREIRA
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JOSE DANIEL DINIZ MELO
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MARIA ODILA HILÁRIO CIOFFI
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Data: 16-oct-2017
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Resumen Espectáculo
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Self-healing techniques in epoxy resins have been developed to improve the life-span and reduce costs associated with repairs of these materials during service. The addition of thermoplastics into the thermoset matrix producing mendable resins appears as a promising self-healing technique. In this study, poly(ethylene-co-methacrylic acid) (EMAA) was added to carbon fiber-epoxy composites to produce a self-healing system. Specimens with different percentages of thermoplastic were manufactured and interlaminar shear strength test (ILSS), dynamic mechanical analysis (DMA), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and field-emission gun scanning electron microcopy (FEG-SEM) were employed in order to evaluate the effect of the addition of the thermoplastic to the composite and its behavior before and after a healing cycle. The healed samples had similar mechanical properties to the properties presented by the samples before healing. However, for higher percentages of EMAA, there was a reduction of these properties, besides a reduction of Young’s modulus and Tg, in relation to the values presented by the unmodified composite. SEM images confirmed the strong adhesion between EMAA and epoxy resin, producing an adhesive layer that prevented the formation of delamination in the mid-plane of the laminate.
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18
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PABLO RODRIGO PADILHA HONÓRIO
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DEVELOPMENT OF MARKERS BY TRACES OF CHEMICAL ELEMENTS FOR IDENTIFICATION OF ELECTRICAL CABLES VIA X-RAY FLUORESCENCE.
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Líder : AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MIEMBROS DE LA BANCA :
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AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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JORGE MAGNER LOURENÇO
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NICOLAU APOENA CASTRO
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Data: 24-oct-2017
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Resumen Espectáculo
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The present work has as objective the study and development of markers based on traces of chemical elements for the identification of electrical cables of aluminum and copper by means of a X-ray fluorescence (XRF) portable equipment. The development of chemical markers has as purpose try to solve or minimize the problem of theft of electric cables in the country, which has caused huge losses and disorders for companies and population. In this sense, the markers were developed using a polyester-based varnish and an epoxy resin, which were doped with Cr2O3 particles. The markers were produced with additions of 1 %, 2 %, 5 % and 10 % of bulk weight of Cr2O3 in polymer resins and they were applied on cables of bare aluminum and isolated copper. After the markers were applied, the cables were analyzed via XRF, then fused, and again analyzed by XRF, whit the objective to check the remained of the Cr element, even after a possible recycling of cables. The results showed that the chemical markers are efficient for identifying the Cr element via laboratory FRX even with only 1 % bulk addition of Cr2O3 on the surface of Al and Cu cables, with both types of resins, however, it is not sufficient for identification after re-fusion of the conductors. The markers containing 2 % and 5 % of Cr2O3 Showed little efficiency in the identification of Cr after re-fusion. Only the markers made with polyester resin containing 10 % of Cr2O3 proved to be efficient after the Al re-fusion and were identified in all analyzed samples.
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19
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ANDERSON DE AZEVEDO GOMES SANTIAGO
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Characterization of the photoluminescent properties of Ba1-xZnxMoO4 synthesized by the ultrasonic pyrolysis spray method
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Líder : MAURICIO ROBERTO BOMIO DELMONTE
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MIEMBROS DE LA BANCA :
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FABIANA VILLELA DA MOTTA
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MARIO GODINHO JUNIOR
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MAURICIO ROBERTO BOMIO DELMONTE
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Data: 18-dic-2017
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Resumen Espectáculo
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Ba1-xZnxMoO4 (x = 0, 0.25, 0.5, 0.75 and 1) powders were synthesized, in a one-step, by the ultrasonic spray pyrolysis method, using temperatures of 1000 ºC and 1100 ºC. Time for particle formation within the reactor was approximately 1 min. The samples were structurally characterized by the X-ray diffraction and morphologically by the field emission scanning electron microscopy (FESEM). Optical properties of the samples were studied using UV-visible and photoluminescence (PL) spectroscopies. The DRX patterns showed that the samples with x = 0 and x = 1 have crystalline tetragonal scheelite and triclinic structure, respectively, without the presence of secondary phases. On the other hand, Rietveld refining of the DRX patterns of samples with x = 0.25, 0.5 and 0.75 revealed the formation of a heterostructure tetragonal/triclinic, in which atomic substitution of Ba2+ by Zn2+ in the tetragonal structure of the BaMoO4 and triclinic structure of the ZnMoO4 occurring the atomic substitution of Zn2+ by Ba2+, perceiving a slight increase portion of the tetragonal phase when the pyrolysis temperature increases. Thus, these modifications promote small structural distortions in these materials, being easily observed in the angles and edges of the base that delimit the tetrahedron [MoO4] of these molybdates. FESEM micrographs showed that the particles obtained have predominantly spherical morphology with diameters ranging from 100 to 1500 nm. It was found that the primary particles forming microspheres of samples with x = 0 have high dimensions relative to the final size of microspheres, on the other hand for samples with x = 1 the primary particles exhibit low dimensions relative to microspheres. Thus, the decrease of the primary particles forming the microspheres was noted with the increase of x of Ba1-xZnxMoO4, that is, with increase of the atomic substitution of Ba2+ by Zn2+. This fact is given by the difference in solubility of the barium and zinc precursor reagents, because solutes with a high degree of supersaturation, such as zinc nitrate, tend to form a larger number of crystallites of nanometric sizes. The gap energy of the Ba1-xZnxMoO4 ranged from 4.56 eV to 4.17 eV, with the powders with x = 0, obtaining the highest values (4.54 eV and 4.56 eV) and the powders with x = 1 the lowest values (4.17 eV and 4.26 eV). In this way, it was noticed that the gap energies of the samples decrease with the increase of the value of x, that is, with increasing substitution of the Ba2+ for the Zn2+ atoms. Therefore, this phenomenon occurs due to atomic substitution raising the degree of disorder of the samples, increasing the intermediate intervals between the conduction and valence bands, which will result in the decrease of the gap band. Photoluminescent (PL) spectra of the samples showed broad band behavior, with predominant emission in the orange-red region and small emission contribution of the blue-green region. For samples with x = 0, the PL emission phenomenon is related to order-disorder degree of the [BaO8] complexes and oxygen vacancies of the [MoO4] complexes. For samples with x = 1, this phenomenon is related to the order-disorder degree of the [ZnO6] complexes and oxygen vacancies of the [MoO4] complexes. While, for samples with heterostructure tetragonal/triclinic, the PL emission is given by the degree of order-disorder and the charger transfer between the [BaO8] and [ZnO6] complexes, and oxygen vacancies of the [MoO4] complexes. The chromaticity coordinates x and y showed that the samples with x ≤ 0.75 exhibit in orange emission, however, the samples with x = 1 presented white emission.
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Tesis |
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1
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ROGERSON RODRIGUES FREIRE RAMOS
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PROCESSO DE PRODUÇÃO DE MANTAS NÃO TECIDAS TUBULARES DE MICRO E NANOFIBRAS POR FIAÇÃO POR SOPRO EM SOLUÇÃO
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Líder : JOSE DANIEL DINIZ MELO
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MIEMBROS DE LA BANCA :
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JOSE DANIEL DINIZ MELO
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ANA PAULA CYSNE BARBOSA
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MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
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ELITON SOUTO DE MEDEIROS
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JULIANO ELVIS DE OLIVEIRA
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Data: 02-feb-2017
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Resumen Espectáculo
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Structures produced from bioresorbable polymers are of great interest because of their potential uses in medical applications. In this work, a process of production of micro and nanofibrous tubular structures by solution blow spinning (SBS) was developed, using a multi-ejection matrix and a collection system based on a rotational conical collector. The process also includes an extracting step and post-spinning process by heat treatment in oven. Poly(D, L lactic acid), PDLLA, fibrous tubules were produced. The effects of collection and heat treatment on their morphological properties (SEM), crystallinity (DSC and DXR), diameter distribution, hydrophobicity (contact angle) and mechanical properties such as modulus of elasticity, stress and strain at rupture (tensile test) were evaluated. DSC analyzes indicated an increase in fiber crystallinity with increasing heat treatment time and temperature and SEM images indicated that the average fiber diameter tends to decrease at the beginning of crystallization. Wettability tests indicated that the surface energy of the material does not change significantly as a function of the degree of crystallinity. The results of the tensile tests showed that the degree of crystallinity is determinant for the mechanical performance of the mats that form the wall of the tubular structures and that the heat treatment raises the modulus of elasticity and reduces the deformation at break. The tubules submitted to the intermediate levels of heat treatment (85 ° C for 3.5 min) presented mechanical performance similar to that of samples treated at the highest levels (115°C for 6.5 min) and the tensile properties were comparable to those of Saphenous vein of an adult person. Analysis of the influence of the collection variables on mechanical properties of the tubules indicated that an increase in spinning gas pressure and a reduction in the diameter of the extractor increases elastic modulus and the tensile strength without significantly affecting the deformation at break. The angular velocity of the conical collector did not interfere in the mechanical behavior of the tubules. In summary, it was possible to produce micro and nanofibrous tubules with great potential in angiogenesis by combining SBS with an appropriate winding and extraction process.
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2
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ROBERTO RODRIGUES CUNHA LIMA
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APPLICATION OF MODIFIED CLAYS FOR HARD WATER SOFTENING
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Líder : VALTER JOSE FERNANDES JUNIOR
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MIEMBROS DE LA BANCA :
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VALTER JOSE FERNANDES JUNIOR
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ANTONIO SOUZA DE ARAUJO
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NEDJA SUELY FERNANDES
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ANA CATARINA FERNANDES CORIOLANO
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FRANCISCO LAERTE DE CASTRO
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Data: 03-mar-2017
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Resumen Espectáculo
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The need to diversify the ways of treating water from different sources and for different purposes becomes more urgent every day, especially when considering the economic and social impacts associated with management of an irreplaceable natural resource. Clays can be applied for softening hard water, expanding perspectives of water use, with the development of sustainable technological devices and processes. In this study, in addition to those that were kept untreated, bentonite samples were activated with HCl and H2SO4, while vermiculite samples were modified with HCl, NaOH and NaCl, for adsorption tests of Ca2+ ions using standard calcium solution and real hard water adequately collected from wells in the central region of the state of Rio Grande do Norte, Brazil. A reduction of 22.8% in the hardness of the standard calcium solution was verified with H2SO4-activated bentonite, while higher efficiency was verified with vermiculites treated with HCl, NaOH and NaCl, with hardness reductions on the standard calcium solution of 43.6%, 46.3% and 57.5%, respectively, and reduction of up to 45.2% in the hardness of the real sample, with NaCl-modified vermiculite, which generated the best results. It has been proven that it is possible to recondition the vermiculite, and that electrolyte concentration and successive treatment influence the adsorptive capacity of this NaCl-modified clay. Vermiculite saline treatment can be performed simultaneously with a combination of Na+ and K+ as exchangeable cations. Clay modifications were tracked with XRD, SEM, TG, DTG, EDX, BET and physical-chemical parameter measurements. Further research should be encouraged for the refinement of techniques and methods applying clays for the recovery and management of water resources.
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3
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SAMARA MELO VALCACER
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STUDY ON THE EFFECT OF ALUMINA (Al2O3) ADDITION ON THE COMPOSITE WC-3% Ni SINTERIZED WITH LIQUID PHASE
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Líder : UILAME UMBELINO GOMES
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MIEMBROS DE LA BANCA :
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UILAME UMBELINO GOMES
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FRANCINE ALVES DA COSTA
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ARIADNE DE SOUZA SILVA
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GILSON GARCIA DA SILVA
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LEILIANE ALVES DE OLIVEIRA
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TERCIO GRACIANO MACHADO
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Data: 17-mar-2017
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Resumen Espectáculo
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The need for materials with high performance has driven the study of new systems as an alternative to existing ones. The composite materials are indicated when there is this necessity, therefore, can unite characteristics of different materials in a single body. A composite well known for its properties is tungsten carbide and cobalt (WC-Co). It is known that the mentioned material presents high hardness being indicated for use in cutting tools, however, as the cutting speed increases, the studies indicate that there is oxidation, thus generating a break in the composite. As an alternative to the WC-Co system, the cobalt substitution is currently studied by nickel, however the WC-Ni composite presents a low hardness when compared to the WC-Co. The present study proposes the study of a new material, which is a mixture of carbide of tungsten, alumina (Al2O3) and nickel. The study aims to establish characteristics of the composite WC-3% Ni when added with 5, 10 and 15% w Al2O3. The process of obtaining it was via powder metallurgy. High energy milling (400 rpm), uniaxial compaction at 400Mpa and vacuum sintering were carried out and in a dilatometric oven at temperatures of 1450 and 1550 ° C with a sintering level of 1h. The samples were characterized by: laser particulometry, XRD, SEM, hardness, density and densification of the samples. The results were promising since there was interaction between WC-Ni in all compositions. The sintering in dilatometric furnace presented better densities and hardnesses being the composition with addition of 5% p of alumina the more dense in the two processing temperatures, with relative density superior to 90%.
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4
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ZODINIO LAURISA MONTEIRO SAMPAIO
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Structural lightweight concrete formulation with residues and low consumption of cement
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Líder : ANTONIO EDUARDO MARTINELLI
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MIEMBROS DE LA BANCA :
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ANTONIO EDUARDO MARTINELLI
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JÚLIO CÉZAR DE OLIVEIRA FREITAS
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KLEBER CAVALCANTI CABRAL
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SANDRO MARDEN TORRES
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ULISSES TARGINO BEZERRA
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Data: 25-abr-2017
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Resumen Espectáculo
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The high-energy demand involved in the construction industry and the increasing consumption of concrete made this material an ideal option for the recycling of by-products from various industries such as: porcelain polishing residue (PPR); Tire rubber residue (TRR) and limestone residue (LSR). These residues often lack a treatment that will contribute to the degradation of the environment. Lightweight concrete (LWC) has been used in civil construction due to its benefits, which include: reducing the concrete's dead weight; increase of useful area; handling and less costly transport operations; Increased thermal and acoustic insulation and fire resistance. In the production of lightweight concrete, usually part or all of the aggregates are replaced by lightweight aggregates such as expanded clays (EC), TRR, pome stone, expanded vermiculite and others. LWC usually consume more cement because of the low strength of porous aggregates used in manufacturing. In this sense, the use of by-products that will increase the volume of the concrete without damaging the properties, can be a viable option in the production of low cost and sustainable LWC. The general objective of this work was to analyze the mechanical and thermal behavior of structural lightweight concrete (SLWC) produced with EC in replacement of the aggregate and with the addition of PPR, TRR and LSR to replace the small aggregate. And finally create a low-cost SLWC with good mechanical properties with minimal cement consumption. For this purpose, a 2³ factorial design was used for the choice of SLWC with the best performance in terms of consistency, mechanical properties and density. Subsequently, reductions of 10, 20 and 30% of cement were performed on SLWC that presented better performance and were characterized by mechanical tests. The best SLWC mix resulting from the combination of mechanical properties and cement consumption was characterized by: permeability tests; Flexural strength; TG/DTA; XRF; XRD; SEM; Thermal capacity; Thermal conductivity and thermal diffusivity. Finally, an economic analysis of the feasibility of the use of SLWC obtained with the reduction of cement was carried out. The results showed that residues contents around 21% presented better combination of properties. By maintaining the amount of residue at optimum levels it was possible to produce an economically viable CLE with good rheological, mechanical and thermal properties with a minimum cement consumption.
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5
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MICHELINE DAMIAO DIAS MOREIRA
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ROUTES OF CHEMICAL SYNTHESES FOR OBTAINING NANOPARTICLES OF Ag/g-Al2O3 and Ag/ZnO WITH BACTERICIDAL PROPERTIES.
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Líder : CARLOS ALBERTO PASKOCIMAS
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MIEMBROS DE LA BANCA :
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ANDRE LUIS CALADO ARAUJO
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CARLA GRACY RIBEIRO MENEZES
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CARLOS ALBERTO PASKOCIMAS
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FABIANA VILLELA DA MOTTA
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MAURICIO ROBERTO BOMIO DELMONTE
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Data: 27-abr-2017
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Resumen Espectáculo
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The progressive demand for water has made the treatment and reuse of effluents a subject of worldwide relevance. Considering this situation, research has been carried out on the use of nanometric materials to obtain nanocomposites with antibacterial properties. In order to improve the obtaining of new materials, several methodologies and preparation techniques have been developed with the aim of controlling the shape and size of particles, which will consequently improve and optimize their properties. This work consists of obtaining, characterization and antibacterial evaluation of nanocomposites obtained by the impregnation of silver (Ag) in commercial alumina (g-Al2O3) and zinc oxide (ZnO) from different synthesis routes: hydrothermal method assisted by micro- Waves, sonoquímico and association of the sonoquímico and hidrotermal, destined to the disinfection of wastewater. A comparative study was performed between the nanoparticles g-Al2O3 and ZnO synthesized by sonochemical and hydrothermal microwave methods, investigating the influence of composition and distribution of particle size on the properties of these nanoparticles.Impregnations of 4%, 8%, 12% and 16% Ag in g-Al2O3 and ZnO were tested. The nanopó was applied in effluent coming from compact ETE (Sewage Treatment Station), after the secondary treatment step, and then, through bacteriological analyzes, the efficiency in the removal of the pathogenic indicators of contamination was evaluated. The results regarding the use of the ZnO nanocomposite impregnated with 8% Ag in the ratio of 0.3g/300 mL for a contact time of 30 minutes, indicated an efficiency of 100.00% in the removal of total coliforms, thermotolerant coliforms and Escherichia coli, reaching standards equal or superior to the already established disinfection techniques. The network parameters of the nanocomposites obtained through XRD, together with the FRX characterization techniques, particle size analysis and the micrographs from the SEM/FEG and EDS confirmed the adequate impregnation of the silver in the oxides. ICP-OES plasma optical emission spectrometry revealed that all samples analyzed had a silver content below the detection limit LD<0.50 mg/L, taking into account the maximum levels established by the current standards, as well as the toxicity to Health and the environment.
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6
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CÁSSIA CARVALHO DE ALMEIDA
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CATALYTIC MATERIALS BASED ON NICKEL AND COBALT SUPPORTED IN SBA-15 TO USE IN THE STEAM REFORM OF THE ETHANOL AND IN THE DRY REFORM OF NATURAL GAS
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Líder : DULCE MARIA DE ARAUJO MELO
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MIEMBROS DE LA BANCA :
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DULCE MARIA DE ARAUJO MELO
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ELEDIR VITOR SOBRINHO
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RENATA MARTINS BRAGA
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FLÁVIA DE MEDEIROS AQUINO
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RAIMUNDO CRISOSTOMO RABELO NETO
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Data: 26-may-2017
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Resumen Espectáculo
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In the last years, the processes of reform for the production of hydrogen as an energetic vector have been well studied because of the increase of the demand for alternative technologies of energy generation, showing a good relation cost/benefit when compared to other technologies of hydrogen production. In addition, they have advantages from an environmental point of view, not contributing to the increase of CO2 concentration in the atmosphere. However, hydrogen production through reform processes, while promising, still presents many technological bottlenecks, requiring advances in new materials with catalytic properties. In this proposal, the goal of this work is to obtain catalytic materials with high reactivity and selectivity for products in the face of reactions of steam reforming of ethanol (SRE) and dry reforming of methane (DRM). Catalysts based on nickel and cobalt supported on SBA-15 were prepared by wet impregnation method and characterized before and after the catalytic tests by several techniques: Thermogravimetric Analysis (TGA), Fourier Transformer Infrared Spectroscopy (FT- IR), X-ray diffraction (XRD), Temperature Programmed Reduction (TPR), Nitrogen Adsorption and Desorption, X-ray Diffraction in situ (XRD in situ), and Scanning Electron Microscopy (SEM) with Energy Spectroscopy (ES) to understanding the mechanisms involved in the reforming reactions and also responsible for the deposition of carbon on the catalysts. The catalysts tested against the steam reaction of ethanol for 6 hours at 500ºC presented an initial conversion around 80-100%, with H2 (65-70%), CO2 (18-23%) and only traces of CO (0.5-10%), but they suffered a rapid deactivation in the first hours of test, being more promising in the dry reforming reaction of methane, which showed good activity and stability during 10 hours of reaction at 700ºC with conversions (CH4 and CO2) and H2 yields above 80% and low carbon deposition.
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7
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GINEIDE CONCEIÇÃO DOS ANJOS
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Use of diatomite as support of Ni and Co catalysts in the dry reforming reaction of methane.
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Líder : DULCE MARIA DE ARAUJO MELO
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MIEMBROS DE LA BANCA :
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DULCE MARIA DE ARAUJO MELO
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ELEDIR VITOR SOBRINHO
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RENATA MARTINS BRAGA
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JOANA MARIA DE FARIAS BARROS
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RAIMUNDO CRISOSTOMO RABELO NETO
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Data: 26-may-2017
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Resumen Espectáculo
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Due to the environmental demands in the past years, the search for more environmental-friendly fuels has intensified. The utilization of hydrogen gas as energetic vector has been highlighted in this scenario in a way that researches of its production have grown substantially. The main utilized routes for the hydrogen obtainment are the catalytic reform reactions, in which the development of adequate catalysts became an essential tool in these processes. However, the major difficulty in these reactions to produce H2 is to find stable catalysts for longer periods, that are resistant to the carbon accumulation and selective to the formation of hydrogen gas. The catalytic support present an important role in the reform reactions, proportionating a good dispersion and avoiding the active phase synthetization, influencing in a positive way the reactivity and stability of the catalyst. In this context, the diatomite, an amorphous sediment originated from frustules, unicellular algae skeletons, has been studied as a natural catalyst support. Because of that, this work utilized the diatomite as a catalyst support for the dispersing of Ni and/or Co metallic phases, and, posteriorly, evaluate the obtained catalysts in the dry reforming methane process. The mono and bimetallic catalysts with different concentrations were prepared by moist impregnation, with posterior calcination. The support and catalysts were submitted to the following characterizations: X-ray diffraction (XRD), adsorption and desorption of N2 isothermal analysis, thermogravimetric analysis (TGA/DTG), x-ray fluorescence (XRF), temperature programmed reduction (TPR), and scanning electron microscopy (SEM). The catalytic tests were performed in a quartz fixed-bed reactor coupled to a mass spectrophotometer. The results indicated that all the catalysts presented a good catalytic activity, with higher conversion rates and yields of CH4, CO2 and H2 superior to 80%. In all tests, the H2/CO ratio evolution was close to 1. However, the bimetallic catalyst NiCo/D showed the best stability and catalytic activity if compared to the other studied catalysts. Aiming to increase this efficiency, cerium and lanthanum promoters were added to these catalysts. The adding of cerium did not change the yields of the NiCo/D catalyst, while the lanthanum adding increased significantly the yield of H2 and in the H2/CO ratio, showing that the diatomite is a promissory for Nickel and/or Cobalt, and that the NiCo/D is a prominent catalyst for dry reform processes.
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8
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PATRICIA NEVES DE MEDEIROS
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Synthesis of strontium-calcium indate (Sr0,9Ca0,1In2O4) codoped with rare earth ions for application in photoluminescence
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Líder : FABIANA VILLELA DA MOTTA
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MIEMBROS DE LA BANCA :
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FABIANA VILLELA DA MOTTA
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MAURICIO ROBERTO BOMIO DELMONTE
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MICHELINE DAMIAO DIAS MOREIRA
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MAXYMME MENDES DE MELO
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VINÍCIUS DANTAS DE ARAÚJO
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Data: 22-jun-2017
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Resumen Espectáculo
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Nanostructured ceramic materials have been extensively studied in recent years due to their great potential in areas such as photoluminescence, photocatalysis, electrochemistry. These materials allow the improvement of various properties due to their nanometric dimensions. The strontium indate (SrIn2O4) and the calcium indate (CaIn2O4) are oxides with structure of spinel type and orthorhombic crystalline system, being reported in the literature as host lattice for luminescent materials. The ultrasonic spray pyrolysis method allows continuous one-step production of particles with high purity. In this context, the synthesis of Sr(1-x)CaxIn2O4 was performed using the spray pyrolysis method, investigating the influence of the Ca2+ ion content on the photoluminescent properties of the solid solution. After analysis of the results it was verified that the composition Sr0,9Ca0,1In2O4 emitted higher intensity photoluminescent and was selected as host lattice for Rare Earth activator ions (RE3+). The indate Sr0.9Ca0.1In2O4: Eu3+, Tb3+, Tm3+, co-doped at different concentrations (%mol) were synthesized by spray pyrolysis. The obtained samples were characterized by X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (MEV-FEG), photoluminescence measurements (PL), UV-visible spectroscopy (UV-VIS) and photocatalytic activity by degradation of the methylene blue dye. The results of X-ray diffraction confirmed the formation of the strontium indate phase with orthorhombic structure. From the micrographs it can be observed the formation of microspheres composed of nanoparticles. The photoluminescence spectra of the Sr(1-x)CaxIn2O4 samples showed broadband emission and the Sr0,9Ca0,1In2O4 RE3+ (Eu3+, Tb3+, Tm3+) showed narrow and intense bands, characteristic emissions of RE3+ ions. The Sr(1-x)CaxIn2O4 samples showed low photocatalytic activity, with a maximum degradation of 45% of the dye. According to the results obtained, the strontium and calcium indate co-doped with RE3+ ions presents potential application in the area of photoluminescence.
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9
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ADRIANO LINCOLN ALBUQUERQUE MATTOS
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ADDING VALUE TO LIGNOCELLULOSIC WASTE FROM REGIONAL BIOMASS BY POLYMER COMPOSITES
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Líder : EDSON NORIYUKI ITO
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MIEMBROS DE LA BANCA :
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EDSON NORIYUKI ITO
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JOSE HERIBERTO OLIVEIRA DO NASCIMENTO
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ROSANGELA DE CARVALHO BALABAN
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DIEGO LOMONACO VASCONCELOS OLIVEIRA
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MEN DE SÁ MOREIRA DE SOUZA FILHO
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Data: 28-jun-2017
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Resumen Espectáculo
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Lignocellulosic fibers have become an economical and ecological alternative for use as reinforcements and fillers in composites made of virgin or recycled polymers. The present work was subdivided in three papers that focus different aspects of the development of composites. The first one had involved the modification of lignocellulosic particles, using the cashew nut shell liquid (CNSL) as the source of cardanol. The objective was increasing in the degradability of polypropylene (PP) composites made of different types of lignocellulosic particles. Thermo-oxidation tests and analyzes of the mechanical behavior, chemical composition and physical properties of the samples allowed the verification that composites produced with CNSL-modified particles degraded in half the time of the conventional ones. The second article aimed at optimizing the methodology of chemical modification of lignocellulosic particles surface with CNSL that can also be used as an intermediary step in further functionalization of lignocellulosic particles, as it introduces upon its surface higher reactivity sites. The efficiency of the chemical modification methodologies was evaluated with the use of scanning electron microscopy (SEM), infrared spectroscopy (FTIR), thermogravimetry (TGA) and contact angle. The behavior of composites made of the modified particles in polypropylene matrix was also evaluated by mechanical tests and dynamic mechanical thermal analysis (DMTA). The third paper dealt with the production of PP composites made of cashew wood flour and carnauba leaf flour. The physical, mechanical and morphological properties were evaluated by TGA, differential scanning calorimetry, mechanical tensile and flexural tests, and SEM. Composites made of bulk fibers, mercerized and coupled with maleic anhydride were compared and the best performances were observed in the composites using maleic anhydride as coupling agent and carnauba fibers.
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10
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RAIMISON BEZERRA DE ASSIS
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SYNTHESIS OF SODIUM AND POTASSIUM NIOBATE (K1-xNaxNbO3) WITH PHOTOCATALYTIC AND PHOTOLUMINESCENT PROPERTIES
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Líder : FABIANA VILLELA DA MOTTA
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MIEMBROS DE LA BANCA :
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ANTONIO EDUARDO MARTINELLI
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FABIANA VILLELA DA MOTTA
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MAURICIO ROBERTO BOMIO DELMONTE
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MAXYMME MENDES DE MELO
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NEFTALÍ LENIN VILLARREAL CARREÑO
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Data: 29-jun-2017
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Resumen Espectáculo
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In recent years, photoluminescence and photocatalysis have proven to be a comprehensive field for the research and development of materials technology. The development of new materials has opened new perspectives for the production of devices with highly efficient photoluminescent and photocatalytic properties. Among the promising materials of technological interest are the semiconductors sodium and potassium niobates (KNN), which show good performance in optical and photocatalytic properties. In this work, perovskite structures of sodium and potassium niobate (K1-xNaxNbO3) for x = 0; 30; 50; 70; 100% (mol) were synthesized by the polymer precursor method and heat treated at 600°C, 700°C, 800°C and 900°C for the purpose of investigating their photocatalytic and photoluminescent properties. The samples were characterized by thermal analysis (TG/ DSC), X-ray diffraction (XRD), Raman spectroscopy, infrared absorption spectroscopy (FTIR), UV-vis optical absorption spectroscopy, scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL) and photocatalytic tests on the degradation of methylene blue dye. The results of X-ray diffraction confirmed the formation of the orthorhombic phase of the perovskite KNN, K1-xNaxNbO3 showing long-range organization. The FTIR spectra confirmed the X - ray diffraction data by presenting a reduction of bands related to short vibrations related to the double bonds of Nb = O. SEM images revealed that the KNN niobate samples presented morphology in the form of cubes with different particle sizes, with the presence of agglomerates and partially sintered regions. The optical absorption spectra by UV-vis characterized the niobates as semiconductors, indicating an optical gap between 2.59 eV and 3.35 eV, in addition to showing that the increase of the heat treatment temperature and the sodium concentration promoted an increase of the gap band. Photoluminescence spectra indicated a decrease in FL emission intensity with increasing sodium concentration in the KNbO3 matrix, exhibiting emission at room temperature in the region of violet (433 nm) in red (642 nm). Samples of niobates KN, KNN30, KNN50, KNN70 and NN showed satisfactory degradation rates, presenting excellent results for NaNbO3 (NN) thermally treated at 600°C with 95.95% degradation of the dye. The increase of the sodium concentration improved the photocatalytic performance of the KNN system, being efficient for photocatalytic applications. The results indicate the potential of sodium and potassium niobates in photocatalysis and photoluminescence.
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11
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MEYSAM MASHHADIKARIMI
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OBTAINING TRIPLE LAYER POLYCRYSTALLINE DIAMOND COMPACT BY HPHT METHOD
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Líder : UILAME UMBELINO GOMES
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MIEMBROS DE LA BANCA :
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UILAME UMBELINO GOMES
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RUBENS MARIBONDO DO NASCIMENTO
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FRANCINE ALVES DA COSTA
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CLODOMIRO ALVES JUNIOR
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MARCELLO FILGUEIRA
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Data: 10-jul-2017
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Resumen Espectáculo
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The primary objective of this thesis is to obtain a polycrystalline diamond compact (PDC) with a WC- 10 wt% Co substrate and a sintered polycrystalline diamond top layer via high pressure high temperature (HPHT) sintering method. To achieve this objective, the project has been done in three different stages. The first stage was producing diamond sintered body with a suitable binder, for this reason four different binders was used to sinter diamond powder under HPHT condition. Binders were pure niobium (Nb) and three different mixture of niobium with Iron (Fe), Nickel (Ni) and Cobalt (Co). 10 wt% of binder was used and sintering was carried out at different temperature of 1600, 1700 and 1750°C under 5.5, 6.5 and 7.7 GPa of pressure for three successive holding time of 3 minutes (total 9 minutes). Obtained samples were studies according to relative density, microstructure, and hardness to find the optimum binder and sintering parameters. Studies at this stage showed that using pure niobium as binder and higher pressure and temperature have better results specially by avoiding graphitization during sintering. The second stage of project was done to study the hardmetal substrate at different sintering conditions. At this stage a powder mixture of WC-10 wt% Co was sintered via HPHT at 1500 to 1900°C under 7.7 GPa pressure for 2 and 3 minutes. Microstructural/structural analysis was performed by SEM/EDS and XRD. Hardness, Indentation Fracture Toughness (ITF) and compression tests were also carried out to understand effects of different sintering parameters. At this stage, it was found that full density can achieved for high sintering temperature along with abnormal grain growth. Undesirable ƞ phases were formed only in samples sintered at 1800 and 1900°C. High hardness was observed in range starting from 1250 up to 1650 HV. Third and last stage was done according to the results achieved from previous stages to obtain a triple layer polycrystalline diamond compact. A thin layer of WC 10 wt% Nb/Ni was used as an interface between diamond with pure Nb top layer and WC 10 wt% Co substrate. Sintering was done via HPHT method at 1750°C under 7.7 GPa of pressure. Two different holding time of 6 (three successive 2 minutes) and 9 (three successive 3 minutes) were used. Density, hardness and compression strength were measured and microstructural/structural studies were done via XRD and SEM/EDS. The overall results showed that a new kind of PDC can successfully produce using a new pure niobium binder for diamond without any graphitization. It was also found that using an interface having the resemblance to both substrate and sintered diamond body caused good adhesion between layers that can results in enhanced performance and improving durability of PDC.
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12
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MARIA JOSE SANTOS LIMA
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Synthesis of Nanostructured composite powders (WC-Ni) by APT Carborreduction with Ni(NO3)2.6H2O and its Sintering in Vacuum Oven and by SPS.
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Líder : UILAME UMBELINO GOMES
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MIEMBROS DE LA BANCA :
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UILAME UMBELINO GOMES
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CARLSON PEREIRA DE SOUZA
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FILIPE MARTEL DE MAGALHAES BORGES
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MARCELLO FILGUEIRA
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OSCAR OLIMPIO DE ARAÚJO FILHO
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Data: 18-jul-2017
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Resumen Espectáculo
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In this work WC-Ni composite powders were synthesized by carborreduction of the hydrated ammonium paratungstate (APT) mixture with the nickel nitrate in proportions (5% p.Ni, 10% p.Ni and 15% p.Ni) a low temperature (800 ° C to 950 ° C) and small reaction time (90min to 150min) in a single synthesis process. The powders were characterized mainly by X-ray diffraction, Scanning Electron Microscopy (SEM), Dispersive Energy Spectroscopy (EDS), X-ray Fluorescence (FRX), Particle Size Analysis and (BET) and measures of magnetization, coercivity and remanence. The study of crystallite size was obtained from the X-ray diffractograms of post-composites, using the Scherrer equation. A factorial experimental design 23 with three central points was carried out to evaluate the influence of the synthesis conditions on the response variables (crystallite size). The synthesis parameters evaluated in this work were: reaction time (90min, 120min and 150min), synthesis temperature (800 ° C, 850 ° C and 900 ° C) and concentration of nickel by weight (5% p.Ni, 10 % P.Ni and 15% p.Ni). It was possible to produce nanometric WC-Ni composite powders in the desired proportions with the desired purity, with a mean crystallite size varying from 24.2 nm to 38 nm, with a surface area ranging from 24.6m²/g to 46.7 m²/g. The powders presented morphology with particles of varied sizes and shapes, quite agglomerated and also presented a good dispersion and homogenization of the phases. The specific characteristics of these nanometric materials provide their use for both the hard metal in catalytic reactions.Therefore, the composite powders obtained in this work were applied in the production of WC-Ni hard metal by solid and liquid phase sintering using conventional sintering and Spark Plasma Sintering techniques for comparison purposes. In the sintered samples the measurements of Vickers hardness and density by pycnometry were performed. We also performed XRD, SEM and EDS analyzes with mapping. The best results for the sintered WC-Ni were obtained for the sintered samples via SPS at 1350ºC, showing Vickers hardness (2322 HV) and density (97.67%) higher than the samples sintered by conventional sintering at higher temperatures.
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13
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ELANIA MARIA FERNANDES SILVA
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STRUCTURED OXIDES OF PEROVSQUITA TYPE FOR GAS GENERATION OF SYNTHESIS VIA REFORMATION OF METANE DRY
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Líder : DULCE MARIA DE ARAUJO MELO
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MIEMBROS DE LA BANCA :
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DULCE MARIA DE ARAUJO MELO
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ELEDIR VITOR SOBRINHO
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RENATA MARTINS BRAGA
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ELSON LONGO DA SILVA
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FLÁVIA DE MEDEIROS AQUINO
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Data: 25-jul-2017
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Resumen Espectáculo
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High-performance catalysts have been widely researched in order to increase the yield in methane dry reforming processes (DRM). Some transition metals, especially nickel, are largely studied for this purpose. Due to its catalysts’ properties, thermal and chemical stability, perovskite-type oxides ABO3 are promising materials as catalytic precursors in DRM processes. In this work perovskite-type oxides ABO3 were synthesized by microwave assisted combustion using urea as fuel and calcinated at 900 ºC for 2h. After the calcination, all the prepared oxides were impregnated with 20% (w/w) of nickel and calcinated again at 600ºC for 2h. The samples were characterized by the following techniques: x-ray diffraction (XRD), temperature programmed reduction (TPR), and dispersive energy scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Methane reforming tests with CO2 were performed for evaluation of these materials as catalysts in the production of syngas. After the reforming tests, the catalysts were submitted once again to characterizations for the evaluation of the existence of carbon in the oxides’ surface. According to the X-ray diffractograms, secondary phases of nickel oxides were formed after the nickel impregnation in the powders. The SEM images showed that the impregnation methodology resulted in a homogeneous dispersion of the nickel oxide particles on the perovskite’s surface.
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14
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CLEONILSON MAFRA BARBOSA
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SYNTHESIS AND CHARACTERIZATION OF MIXED NIOBIUM AND TANTALUM ELECTROCATALYSTS DOPED WITH Co, Cu AND Ni PRODUCED FROM COLUMBITE/TANTALITE.
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Líder : CARLSON PEREIRA DE SOUZA
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MIEMBROS DE LA BANCA :
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ANA KARLA COSTA DE OLIVEIRA
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ARIADNE DE SOUZA SILVA
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CARLSON PEREIRA DE SOUZA
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FABIO GARCIA PENHA
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UILAME UMBELINO GOMES
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Data: 31-jul-2017
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Resumen Espectáculo
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This paper proposes an alternative route for producing catalysts for methanol and ethanol oxidation reactions to be applied on fuel cells. Those catalysts are based on oxides and precursors of mixed niobium and tantalum nanostructured materials in their pure and doped (with Co, Cu or Ni) forms. These materials are obtained from columbite/tantalite, which is the base mineral for Nb, Ta, extracted from Rio Grande do Norte’s mineral resources. At first, an experimental planning for the complete purification of the mineral was performed. After purification, 10%wt. doping with each of the metals, and thermal treatment at three different temperatures (110,400 and 600°C) was carried out. Un-doped purified oxides were then subject to complexation process followed by metal addition (doping) and thermal treatment. Purified and thermally treated mineral was characterized by X-Ray Fluorescence (XRF) and X-Ray Diffraction and complete purification was attained. Complex precursors were evaluated on the basis of XRD, Infra-Red Spectroscopy (IR), thermal behavior (TG/DSC and DTA) and morphology (Scanning Electron Microscopy) and presented particle sizes under 0.2 µm, elevated weight loss (76.6%) and a porous structure of irregular shape. Pure and doped catalysts were characterized on XRD, XPS (X-Ray Excited Photon Spectroscopy), SEM and TEM (Transmission Electron Microscopy) basis, presenting indication of catalytic properties interesting for oxidation reactions, such as quick surface reduction. Electrical evaluation of the catalysts was performed according to Differentia Pulse Voltammetry (DPV) with the use of micro sensors during alcohol oxidation reactions. These analyses indicated the excellent conducting characteristics of the materials as electric current flow was increased in two orders of magnitudes in comparison to gold electrodes. The best catalytic behaviors were observed when dopping was performed with copper, followed by nickel, cobalt and without dopant addition. Therefore, the synthesized materials presented characteristics that indicate their suitability for use as fuel cells electrodes.
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15
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CIRO JOSÉ FERREIRA RODRIGUES
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Hydrothermal synthesis and characterization of Ce-Al and Ce-Al composites
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Líder : ANTONIO EDUARDO MARTINELLI
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MIEMBROS DE LA BANCA :
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ANTONIO EDUARDO MARTINELLI
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DULCE MARIA DE ARAUJO MELO
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RUBENS MARIBONDO DO NASCIMENTO
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DANIEL ARAÚJO DE MACEDO
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DANIEL ZANETTI DE FLORIO
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Data: 17-ago-2017
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Resumen Espectáculo
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Solid Oxide Fuel Cells (SOFCs) are among modern devices that generate energy from hydrogen sources. SOFCs consist basically of three ceramic constituents acting as electrodes and electrolyte. Yttria-stabilized zirconia/NiO are traditional materials used as mixed anodes that operate with different sources of hydrogen. Although YSZ-NiO depicts high electrical energy conversion, it can only operate between 800 and 1000ºC. Alternative materials based on doped ceria show similarionic conductivity, lower ohmicloss and become operational between 500 and 800ºC. In a mixed anode composition, NiO acts as catalyst in the fuel reform, granting high electrical conductivity. On the downside, the costs of the material are relatively high, and the catalytic activity is decreased by the production of coke. The present study aimed at evaluating the synthesis of mixed ceria-doped anodes using different catalysts, i.e., Al2O3 and SnO. NiO was also used as reference for the efficiency of electric conductivity. The following compositions were synthesized by the microwave assisted hydrothermal synthesis: Ce0.8Sm0.2O1.95-Al2O3 (SAL).Ce0.8Gd0.2O1.95-Al2O3(GAL).Ce0.8Sm0.2O1.95-SnO2 (SSN).Ce0.8Gd0.2O1.95-SnO2 (GSN).Ce0.8Sm0.2O1.95-NiO (SNI) and Ce0.8Gd0.2O1.95-NiO (GNI).The powders were characterized by SEM, thermal analysis and XRD. The electrical conductivity was evaluated by cyclic voltammetry. The method of synthesis was efficent in the preparation of all compositions studied. The crystallinity of the powders was compatible with that of other synthesis methods. SAL and GAL depicted high values of electrical conductivity, as a consequence of the relatively low densities of anodic and cathodic current. Measured peak currents were 1.01 x 10-5 A/mm² for SSN,6.17 x 10-5 A/mm² for GSN, 1.60 x 10-5 A/mm² for SNI and 1.81 x 10-4 A/mm² for GNI. These values suggest the occurrence of electrocatalytic reactions and low electrical conductivity for this kind of electrochemical analysis.
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16
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EMANOELA PEREIRA DE MATTOS
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HIGH TEMPERATURE BRAZING OF LEAN DUPLEX AND DUPLEX STAINLESS STEELS WITH AMORPHOUS NICKEL-BASED FOILS
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Líder : AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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MIEMBROS DE LA BANCA :
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AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
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RUBENS MARIBONDO DO NASCIMENTO
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NICOLAU APOENA CASTRO
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ALOISIO NELMO KLEIN
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WANDERSON SANTANA DA SILVA
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Data: 25-ago-2017
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Resumen Espectáculo
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Duplex stainless steels, characterized by biphasic microstructure composed of similar fractions of ferrite and austenite, have been expanding their application in several fields, to the detriment of the use of traditional austenitic and ferritic stainless steels, in particular in the chemical and petrochemical industries where they can advantageously meet the requirements of mechanical resistance and corrosion in aggressive media. For fabrication of components with complex geometries and / or with reduced thickness sheets the most indicated processes are solid state diffusion welding and high temperature brazing (BAT) over conventional fusion welding methods. In this context, this work initially describes the results of BAT tests on austenitic stainless steel AISI 316L, exploring the applicability of this technology as an alternative manufacturing route for compact heat exchangers.. In addition, as main objective of the work were evaluated in more detail different brazing systems formed by 3 duplex stainless steels and 5 different nickel-based addition alloys. As base metals were used plates of duplex stainless steels UNS S32101 and UNS S32304 and duplex UNS S32205 and as addition metals, amorphous nickel-based foils with different amounts of alloying elements such as Cr, Fe and in particular the Si metalloids , B, P and C. The brazing process was carried out in a high vacuum atmosphere (10-4 mbar), under temperatures of 1020, 1100 and 1160 ° C for times of 30 minutes and 1 hour. A wedge brazing test at 1020 ° C with subsequent heat treatment (1000 and 1100 ° C for 60 and 120 minutes) was performed for the lean duplex UNS S32101 steel with addition alloy containing P in order to determine the behavior of intermetallics in the joint. The characterization of the brazed joints for the microstructural integrity of the steels, the presence of intermetallic phases in the melting zone and the base metal / metal addition interface was performed by optical microscopy, field emission scanning electron microscopy, dispersive energy spectroscopy, backscattered electron diffraction, X-ray diffraction and Vickers microhardness. The best-performing addition metal is the Si-B addition alloy, with continuous γ-Ni phase brazing and dispersed precipitation of borides and nitrides in the brazing zone. The lean duplex stainless steel UNS S32101 showed a phenomenon of high ferritic grain growth under vacuum at temperature over 1100 C, both on the free surface and at the brazing interface. The influence of the brazing atmosphere on the loss by sublimation of Mn and N, as well as the B content in the occurrence of this effect is discussed.
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17
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ERIK DOS SANTOS SILVA
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EFFECT OF THE INCORPORATION OF TREATED SILICA WITH AMINOSILANE IN PMMA/SAN/SILICA NANOCOMPOSITES
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Líder : EDSON NORIYUKI ITO
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MIEMBROS DE LA BANCA :
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AMANDA MELISSA DAMIAO LEITE
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EDSON NORIYUKI ITO
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MARCELO MASSAYOSHI UEKI
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MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
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TOMÁS JEFERSON ALVES DE MELO
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Data: 30-ago-2017
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Resumen Espectáculo
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Nanocomposites of polymers and silica have become the focus of many researchers in recent years because of their excellent properties when compared to individual components. In this work a surface modification treatment of the silica with 3-aminopropyltriethoxysilane (APTES) was carried out for incorporation in the poly(methyl methacrylate)/poly(styrene-co-acrylonitrile)(PMMA/SAN) blend by means of processing in double screw extruder. The effect of the addition of silica nanoparticles with and without surface modification on the structure and properties of PMMA/SAN blends was evaluated in order to promote better mechanical properties without compromising the transparency of the materials produced. The materials were characterized by flow index measures (MFI), mechanical tests of uniaxial traction, 3-point flexural, Rockwell M hardness (HRM) and Shore D, Izod impact, parallel plate rheometry, transmission electron microscopy (TEM), abrasion and scratch tests. The rheological results indicated that there was a reaction between the silica nanoparticles treated with the pure polymers and with the PMMA/SAN blend, proving a useful technique to evaluate possible reactions during the extrusion process. The nanocomposites presented a decrease in the properties of maximum tensile strength, impact strength and elongation at break when compared to PMMA/SAN blends, which showed synergism in the properties of maximum tensile strength and elongation at break. However, the properties of the nanocomposites with modified silica nanoparticles were superior to the nanocomposites without treatment. The addition of silica promoted an increase in the modulus of elasticity, hardness, abrasion and scratch of the nanocomposites produced.
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18
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MARIA DE FÁTIMA DANTAS E SILVA
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PIGMENTS BASED ON SHALE AND IMPREGNATED WITH METALS FOR APPLICATION IN CERAMIC COATINGS.
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Líder : MARCUS ANTONIO DE FREITAS MELO
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MIEMBROS DE LA BANCA :
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MARCUS ANTONIO DE FREITAS MELO
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CARLOS ALBERTO PASKOCIMAS
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ASENETE FRUTUOSO DA COSTA
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JOANA MARIA DE FARIAS BARROS
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PATRICIA MENDONCA PIMENTEL
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Data: 01-sep-2017
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Resumen Espectáculo
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Most industries, the ceramic industry felt the need for the development of new pigments for the production of floors and coatings, in order to meet the demand of ceramics for the decoration of domestic and commercial environments. Given this, there is a great interest in developing new materials that are in accordance with environmental preservation and that are relatively low cost. Retried shale (XR) is a waste from the shale industry, which improperly stored or stored can cause damage to the environment and health. The objective of this study is to evaluate the viability of this material, pure retort shale and retorted shale impregnated with metals, in obtaining pigments that stably color several ceramic matrices; Trying to understand which parameters influence the pigmentation of the enamels. The XR-based pigments were prepared by impregnating the metals via wet and calcined at 700 and 900°C. These pigments were characterized by X-Ray Fluorescence (FRX), X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) spectroscopy in UV-Visible region and Colorimetry. The results confirm the feasibility of the use of shale as a pigment indicating that the use of XR and XR impregnated with iron and chromium nitrate have been favorable processes since they have the advantage of being simple, low cost and reduces the environmental impact caused for this waste. The pigments have light brown, red and shades of gray according to the impregnation and their calcination temperatures, which have become darker at higher temperature.
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19
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EDUARDO RIGOTI
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DEVELOPMENT OF NEW CATALYTIC MATERIALS BASED MOLYBDENIUM SUPPORTED ON ORDERED MESOPOROUS SILICA AND CARBONS FOR HYDRODEOXYGENATION REACTIONS
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Líder : SIBELE BERENICE CASTELLA PERGHER
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MIEMBROS DE LA BANCA :
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SIBELE BERENICE CASTELLA PERGHER
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DULCE MARIA DE ARAUJO MELO
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TIAGO PINHEIRO BRAGA
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ANNE GABRIELLA DIAS SANTOS
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CRISTIANE BARBIERI RODELLA
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VICTOR LUIS DOS SANTOS TEIXEIRA DA SILVA
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Data: 06-oct-2017
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Resumen Espectáculo
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The aim of this thesis was to develop new catalytic materials through the synthesis of mesoporous silica and carbon supports for Mo impregnation to study its catalytic performance in hydrodeoxygenation of gas-phase platform molecules, where it was tried to determine the influence of the catalyst, support and support/catalyst behavior under different reaction conditions. Mesoporous carbons were obtained using the silica materials as a template. The impregnation of molybdenum oxide (MoO3) was carried out by the incipient wetness impregnation to obtain an amount of 4 and 2 Mo atoms/nm² in the silica and carbon supports. Molybdenum carbides were obtained in situ and ex situ by means of Temperature Programmed Carburization (TPC). Characterization was performed using several techniques such as X-Ray Diffraction (XRD), N2 physisorption, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), by these techniques was possible to confirm the synthesis of the silica and carbon materials and the subsequent impregnation of the molybdenum oxide. The techniques of programmed temperature decomposition (TPD), programmed temperature reduction (TPR) and Raman spectroscopy allowed to evaluate the influences of the different reaction conditions on catalysts. The materials were evaluated in hydrodeoxygenation reactions phenol. The results showed an excellent selectivity in reactions with phenol indicating optimal conditions for the reaction at 500 °C. Among all the catalysts studied, the material supported on the CMK-3 carbon replica presented the best results.
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20
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ALESSANDRA AGNA ARAÚJO DOS SANTOS
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STUDY OF THE SINTERING OF TUNGSTEN CARBIDE USING ALTERNATIVES BINDERS 316L AND FeNi WITH CROMIUM ADDED
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Líder : UILAME UMBELINO GOMES
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MIEMBROS DE LA BANCA :
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UILAME UMBELINO GOMES
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ANGELUS GIUSEPPE PEREIRA DA SILVA
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ARIADNE DE SOUZA SILVA
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GILSON GARCIA DA SILVA
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JOAO BAPTISTA MANUEL
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Data: 11-oct-2017
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Resumen Espectáculo
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Hard metal WC-Co is used in machining, drilling or in the manufacture of cutting tools. Nowadays, 70% of the cutting tools are WC-binder. In production numbers, approximately 40.000 MT tools of WC-binder have been produced worldwide since 2011. Today, more than 90% of all WC-binder uses cobalt as the main binder. The superiority of cobalt in relation to other binders is related to several factors, the main being the width of the carbon window. However, it has been studied for decades by alternative binders due to the scarcity and price of cobalt and mainly by the system WCCo be carcinogenic. The goal of this doctoral thesis was to analyze the sintering of the tungsten carbide with alternative binders (steel 316L, and FeNi with addition of chromium content) and verify if they are viable. Both systems WC-316L (binder content of 5, 7 and 20%) and WC-20%FeNi with addition of chromium (chromium content were added in 0, 5, 10 and 20%) were processed by the Powder Metallurgy, following the steps: preparing of the powders, milling (1h, 24h), isostatic compaction (200 MPa) and vacuum sintering (1400oC/1h). The characterization performed in all the sintered samples were: optical and electron microscopy, x-ray diffraction, magnetic saturation and coercivity, hardness, electrochemical etching, and calculation of the vertical sections of the phase diagrams for the system WC-FeNi with addition of chromium. The results obtained and discussed demonstrate that the binder 316L in hard metal is not a viable, because of the high chromium content in this alloy, that forming complex carbides which weaken the structure. The steel 316L binder in hard metal, regardless of the binder content or carbon content, precipitate eta phase (phase that must be avoided in hard metal). For the FeNi binder with addition of chromium, the results demonstrate that the maximum content of chromium that may be contained in solution is approximately 4% (for a binder content of 20%), FeNi with chromium content above 4% will be precipitated eta phase and other stable chromium carbides, the chromium content above 4% will still drastically reduces the carbon window of the composite, making it practically impossible to avoid eta phase or graphite precipitation.
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21
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PALOMA VINACHES MELGUIZO
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Study of the organic cation 2-ethyl-1,3,4-trimethylimidazolium in synthesis of zeolites and zeotypes.
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Líder : SIBELE BERENICE CASTELLA PERGHER
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MIEMBROS DE LA BANCA :
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DULCE MARIA DE ARAUJO MELO
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ELEDIR VITOR SOBRINHO
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FLORIAN EDOUARD PIERRE MENEAU
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KATIA BERNARDO GUSMÃO
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SIBELE BERENICE CASTELLA PERGHER
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Data: 27-oct-2017
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Resumen Espectáculo
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In this PhD thesis the structure-directing agent 2-ethyl-1,3,4-trimethylimidazolium was studied in the context of zeolite and zeotype synthesis in hydrofluoric media. Initially, it was deepened into the study of the pure silica zeolite HPM-1 to understand the role of the cation in the nucleation and growth, explaining the helicoidal channels and the order of secondary building units formation. Subsequently, an alternative methodology of heteroatom introduction, never reported for the present material, was also presented to give HPM-1 catalytic properties. As a result of it, three different Al-HPM-1 samples were obtained, characterized and tested in ethanol dehydration reaction. Finally, an exploratory study of the organic cation in zeotype synthesis (with Si, Al and P) was performed, giving two main SAPO phases: CHA and LTA zeotypes. It was proven that the SAPO-CHA structure was directed not only by the use of the organic cation and the hydrofluoric media, but also its obtention was influenced by the temperature and a combination of dilution and time. In the case of the SAPO-LTA, the directing effect was mainly due to the organic cation.
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22
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JUCIKLÉCIA DA SILVA REINALDO
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RHEOLOGICAL STUDY OF POLYMER BLENDS WITH POLY (METHYL METHACRYLATE) AND DIFFERENTS STYRENIC POLYMERS
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Líder : EDSON NORIYUKI ITO
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MIEMBROS DE LA BANCA :
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EDSON NORIYUKI ITO
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LUIZ ANTÔNIO PESSAN
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MARCELO MASSAYOSHI UEKI
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PANKAJ AGRAWAL
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TOMÁS JEFERSON ALVES DE MELO
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Data: 23-nov-2017
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Resumen Espectáculo
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The aim of this work was to investigate the influence of the effect of the chemical structures on the rheological behavior in the linear viscoelastic of polymer blends consisting of acrylic and styrene polymers, i.e., poly (methyl methacrylate) homopolymer (PMMAh), poly (methyl methacrylate) copolymer (PMMAe), polystyrene (PS), styrene-acrylonitrile copolymer (SAN) and acrylonitrile-butadiene-styrene copolymer (ABS) and methyl methacrylate-butadiene-styrene copolymer (MBS). Preliminary characterization of the pure polymers shows by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) that the copolymers had different chemical structures based on acrylics, styrene, acrylonitrile, butadiene and other elastomer types present in the PMMAe copolymer. The results of the chemical compositions of the styrenic copolymers (SAN and ABS) presented percentage of AN that is within the window of miscibility for mixtures developed with the PMMA, i.e., of 25 and 21% respectively. The rheological results obtained at low shear rates in the region of linear viscoelasticity showed that there was a significant change in the rheological behavior in relation to the use of acrylic homopolymer in the development of the polymer blends, when compared to the use of acrylic copolymerized with elastomeric particles. It was possible to indicate the miscibility mixture of polymer blends with structural variation of the minority components (styrenic polymers) by means of the linear viscoelastic behavior of these polymer blends. The morphological results obtained by scanning electron microscopy (SEM) showed the immiscibility in the polymer blends with PS and a probability of miscibility between the SAN and the SAN phase of the ABS with the PMMAh forming a single phase, corroborating with the rheological results. However, polymer blends with PMMAe and ABS presented complex microrreological results, because both polymers presented elastomeric phases. The morphological results, obtained by transmission electron microscopy (TEM) together with the results of glass transition temperature (Tg) by DSC, led to the proposal in this work that the elastomeric domains of PMMAe are formed by the butyl acrylate-polystyrene copolymer (PBA-co-PS) in core-shell with PMMA.
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23
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ANA PAULA PEREIRA FULCO
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DAMAGE MECHANISMS OF CARBON/EPOXY LAMINATES UNDER FATIGUE LOADING AND HIGROTHERMAL AGING
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Líder : JOSE DANIEL DINIZ MELO
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MIEMBROS DE LA BANCA :
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ANA PAULA CYSNE BARBOSA
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CARLOS ALBERTO CIMINI JUNIOR
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FLAMINIO LEVY NETO
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JOSE DANIEL DINIZ MELO
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RAIMUNDO CARLOS SILVERIO FREIRE JUNIOR
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Data: 30-nov-2017
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Resumen Espectáculo
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Carbon fiber reinforced polymer (CFRP) composites used in aeronautic and aerospace structures are often exposed to cyclic loading and environmental effects such as temperature and humidity, which can lead to degradation and failure of the component. The objective of this work was to study the effects of aging under exposure to high temperature and humidity on the damage mechanisms of carbon/epoxy composites subjected to cyclic loading. Initially, a preliminary accelerated aging study was conducted with unidirectional AS4/8552 samples using an exposure cycle of 8 h of UVA-340 at 80 °C followed by 4 h of condensation at 80 °C, for a total exposure period of 2,160 h. The effects of aging were evidenced by weight loss, fiber exposure, chemical changes, increased crack density in interlaminar shear strength tests, and fiber buckling in fractured samples after compression tests, even though no significant changes mechanical properties were observed. Based on this preliminary work, a study was conducted on [02/902]s laminates of the same material, using an exposure cycle of 8 h at 160 °C followed by 4 h of 80% relative humidity at 70 °C, for a total exposure period of 2,880 h. Afterwards, stress-controlled tension-tension fatigue tests were conducted using a stress ratio R = 0.1 and frequency of 5 Hz. Composites were characterized using Fourier transform infrared spectroscopy (FTIR), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and weight change, before and after hygrothermal exposure. Samples of plain epoxy 8552 were also exposed to the same aging conditions and characterized by optical microscopy (OM), FTIR spectroscopy and weight change. Based on the fatigue life diagrams, a shift function was proposed for the prediction of number of cycles to failure of aged composites based on data from unaged specimens. The study also showed that failure by fracture may not be the best parameter to evaluate the effect of hygrothermal aging on fatigue life of carbon fiber reinforced polymer composites. Other parameters such as delamination and crack saturation are also essential to assess durability of these composites.
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24
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ANA CLÁUDIA MEDEIROS DE CARVALHO
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INFLUENCE OF SYNTHESIS PARAMETERS IN THE MORPHOLOGICAL CHARACTERISTICS OF POLY MICROCAPSULES (UREIA-FORMALDEHYDE) FOR USE IN SELF-TREATMENT SYSTEMS
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Líder : MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
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MIEMBROS DE LA BANCA :
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MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
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ANA PAULA CYSNE BARBOSA
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JOSE DANIEL DINIZ MELO
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EVANS PAIVA DA COSTA FERREIRA
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AMELIA SEVERINO FERREIRA E SANTOS
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JOSIANE DANTAS VIANA BARBOSA
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Data: 13-dic-2017
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Resumen Espectáculo
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Self-healing materials are a class of smart materials with an inherent ability to repair damage, thus recovering their functionality. Urea-formaldehyde microcapsules have been studied to provide self-healing functionality to polymers and polymeric matrix composites. These microcapsules must be strong enough to remain intact during processing of the host polymer, and yet break when the polymer is damaged. A well-known self-healing system comprises an epoxy matrix with urea-based microcapsules containing dicyclopentadiene (DCPD). Upon release, DCPD can undergo ring-opening metathesis polymerization (ROMP) when in contact with a pre-embedded dispersed Grubbs’ catalyst. As the healing agent encounters the embedded catalyst, a polymerization reaction is initiated and proceeds until all released healing agent is consumed. The resulting polymer (poly(DCPD) serves as a bonding agent that bridges the crack, regaining much of the initial material properties. In this work, synthesis parameters of poly(urea-formaldehyde) microcapsules were evaluated and an experimental design 22 with three central points was assembled, with the objective of analyze the influence of agitation rate and pH in the size of microcapsules and thickness of capsules shell. The influence of agitation rate on microcapsules size and pH on shell thickness could be proven. From the experimental design results, microcapsules with different core materials such as, vegetable oil (soybean, olive, linseed and coconut), endo-dicyclopentadie and 5-etilidene 2-norbonene (ENB) were synthesized presenting same morphological characteristics and size. Capsules were characterized by Fourier infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Microcapsules filled with soybean, linseed oil and endo-DCPD were used in epoxy system with self-healing ability aiming delay corrosion in metallic substrate. Samples with capsules filled with soybean and linseed oils presented excellent anticorrosive results, with emphasis on the system containing capsules filled with soybean oil, which is an economical alternative to the other tested materials. Microcapsules filled with endo-DCPD were used in indentation tests to verify the self-healing effect, however, it was not possible to attest it, since the indentation did not generate a crack in the samples. Therewith, the behavior of the microcapsules obtained under the adjusted conditions of the experimental design was analyzed in epoxy samples by means of tests where cracks were produced using a blade, capsule rupture was verified as consequence of crack propagation. Capsules which presented adequate diameter and shell thicknesses for their use in the proposed self-healing system, were produced. However, due to the agglomeration and poor dispersion of the microcapsules in the epoxy matrix, in addition to the low amount of catalyst presented, the self-healing effect could not be proven in polymeric or polymeric composites samples.
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25
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LUCAS RICARDO FERNANDES FIGUEIREDO
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ADHESIVE PROPERTIES OF BIODEGRADABLE POLYMERS WITH ADDITION OF CELLULOSE NANOWHISKERS
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Líder : JOSE DANIEL DINIZ MELO
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MIEMBROS DE LA BANCA :
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JOSE DANIEL DINIZ MELO
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ANA PAULA CYSNE BARBOSA
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MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
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ELITON SOUTO DE MEDEIROS
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HENRIETTE MONTEIRO CORDEIRO DE AZEREDO
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JULIANO ELVIS DE OLIVEIRA
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Data: 13-dic-2017
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Resumen Espectáculo
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Green adhesives are of great scientific and technological interest as an alternative to conventional commercial products, which often release toxic substances and take long time to degrade. However, the poor mechanical properties and fast degradation of some biodegradable polymers limit their use in most practical applications. In the present work, novel biodegradable composites were prepared using biodegradable polymers and cellulose nanowhiskers (CNW) for their use as wood adhesives. The goal of the investigation was to study the effect of the addition of CNW on the mechanical properties and degradation of the polymers. The biodegradable polymers synthesized by polycondensation based on glycerol and acids were poly(glycerol adipate) - PGA, poly(glycerol maleate) - PGM, poly(glycerol citrate) - PGC, poly(glycerol phthalate) - PGPh, poly(glycerol succinate) - PGSu and poly(glycerol sebacate) - PGS. In addition, the copolymers synthesized were poly(glycerol succinate-co-maleate) - PGMSu, poly(glycerol succinate-co-adipate) – PGASu and poly(glycerol adipate-co-maleate) – PGMA. Cellulose nanowhiskers (CNW) were added to the polymers as an approach for improving the mechanical properties and controlling the degradation rate. Composites were produced with the addition of 0, 5, 10 and 20 wt.% of CNW. The neat polymers and composites were analyzed by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Adhesively bonded joints were produced in test specimens of slash pine (Pinus elliottii) and angelim (Vatairea heteroptera Ducke) and tested under shear by tensile loading and for accelerated aging degradation. Bonded joints produced with polyvinyl acetate - PVAc and cyanoacrylate based adhesives were also tested under the same conditions for comparison purposes. Thermal analyses showed that most of the biodegradable glycerol-based polymers tested are stable up to about 260°C and the addition of CNW increased the thermal stability (Tonset) of some polymers by 26°C up to 48°C, while others were not affected. Analyses of the fracture surface after the shear tests by Scanning Electron Microscopy (SEM) suggest less ductile fracture with the incorporation of CNW to the adhesive. Adhesion measurements indicated that the green adhesives developed from glycerol polymers with 10 and 20% CNW addition showed shear strength superior to the commercial PVAc based adhesive and the best results were obtained for PGASu 20 wt.% CNW (2.57 ± 0.36 MPa) and PGM 20 wt.% CNW (2.33&plusm |