http://hdl.handle.net/11422/7616 Tue, 07 Apr 2026 22:19:16 GMT 2026-04-07T22:19:16Z http://hdl.handle.net/11422/27074 Title: Síntese de nano-suportes poliméricos heterofuncionais para a imobilização da Lipase B de Candida antarctica Author(s)/Inventor(s): Everton, Stefanni de Sousa Advisor: Pinto, José Carlos Costa da Silva Abstract: Heterofunctional nano-supports have emerged in the enzyme immobilization scenario due to the minimization of problems such as diffusion difficulties and low specific area. In addition, these materials are promising due to their ability to specifically interact with the surface of lipases. Therefore, this study aimed to synthesize heterofunctional nano-supports using the monomers methyl methacrylate (MMA), divinylbenzene (DVB), and the functional monomer glycidyl methacrylate (GMA), to develop promising support for use in enzyme immobilizations. In addition, it was sought to find the best support/enzyme ratio as a function of the degree of hydrophobicity and surface functionality. Based on the results of this study, PMMA, P(MMA-co-DVB) and P(MMMA-co-DVB-co-GMA) nano-supports were synthesized with 25 % and 50 % of GMA, thus varying the concentration of the epoxide group belonging to GMA. Finally, the nano-supports produced had their performances evaluated in hydrolysis and esterification reaction, after immobilization of the enzyme lipase from Candida antarctica type B (CAL B). As a result, it was observed that the nanobiocatalysts containing the epoxide group showed better performances, presenting high specific areas, pronounced pore volumes and diameters, and hydrophilic nature. Furthermore, no direct relationship was observed between the degree of hydrophobicity and the activity of the biocatalysts. Thus, it was found that the epoxide group provided a better performance of the biocatalysts by increasing the enzyme loading capacity and the interaction of this group with CAL B lipase. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Thu, 01 Jul 2021 00:00:00 GMT http://hdl.handle.net/11422/27074 2021-07-01T00:00:00Z http://hdl.handle.net/11422/27073 Title: CeO2 nanowires decorated with Ni : influence of incorporation methods on the surface reactivity Author(s)/Inventor(s): Anchieta e Silva, Felipe Advisor: Rodrigues, Thenner Silva Abstract: The influence of the synthesis methods of Ni/CeO2 nanowires nanomaterials was investigated, trying to correlate different physicochemical properties and the catalytic performance for the production of H2 via ethanol steam reforming. The Ni/CeO2 nanowires were synthesized by wet impregnation, nanoparticles impregnation, urea deposition, and BH4 deposition. The Ni/CeO2 different synthesis methods originated four Ni nanostructures. The catalysts synthesized by impregnation methods displayed higher catalytic stability and performance with high H2 yield. In conclusion, the different synthesis methods influenced the surface reactivity of nanomaterials, with the primary influence on the nickel particle size and the degree between the Ni nanoparticles and the CeO2 nanowires support interaction. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Thu, 01 Jul 2021 00:00:00 GMT http://hdl.handle.net/11422/27073 2021-07-01T00:00:00Z http://hdl.handle.net/11422/26179 Title: Nanobiossensor por ressonância plasmônica de superfície para detecção de patógenos Author(s)/Inventor(s): da Silva Arcas, Ariadny Advisor: Martins Werneck, Marcelo Abstract: The bacterium Escherichia coli (E. coli) and the parasite Taenia solium (T.solium) are microorganisms that cause infections in humans. Their main detection methods consist of laboratory analyzes carried out by expensive equipment and reagents, and even so, it can take days to complete the results. In this context, this research presents the design of nanobiosensors by suspensions of gold nanoparticles (AuNPs) and by plastic optical fiber (POF) in a “U” shape coated with either gold nanofilm or coated with AuNPs for E. coli and T. solium detection. POF and nanostructures were used because they allow the development of diagnosis and detection systems by remote monitoring and in real time in an easy-to-handle instrumentation, accurate, and low costly. The nanofilm was produced by cathodic deposition in a sputtering chamber and the AuNPs by chemical synthesis. The sensors were evaluated for stability, variability, and sensitivity. The POF nanobiosensors with gold nanofilm showed a detection limit for E. coli bacteria of 1.5 x 103 CFU/mL. The AuNPs suspension containing antibody for the capture of T. solium antigens showed a detection limit higher than 0.1 µg/mL, corresponding to the concentration range found in human blood. The POF nanobiosensor containing AuNPs showed a sensitivity of 159.43 nm/RIU. Therefore, one tool turns out that this technology can be efficient for routine analysis in scheduled clinics Publisher: Universidade Federal do Rio de Janeiro Type: Tese Tue, 01 Mar 2022 00:00:00 GMT http://hdl.handle.net/11422/26179 2022-03-01T00:00:00Z http://hdl.handle.net/11422/26153 Title: Desenvolvimento de ligas de AISI 316L endurecidas por dispersão de nano-óxidos de ítrio Author(s)/Inventor(s): Martins, Tabatta Regina de Brito Advisor: Santos, Dilson Silva Abstract: Austenitic steels are very important structure materials for fusion and fission nuclear reactors due to their excellent creep resistance at high temperature, and reasonable corrosion and oxidation resistance compared to ferritic steels. However, the ultimate tensile properties and stress corrosion resistance of austenitic steels are inferior at high temperature. The introduction of nano-sized oxide particles are expected to improve the strength and irradiation resistance of austenitic steels, because the oxide particles are very stable even at temperature close to the melting point of the steel and can be effective barriers to the motion of dislocations during tensile deformation. Therefore, the present work proposes a preparation of austenitic stainless steels with 0.35% wt. of Y2O3, Ti, Cu or all of them. They are characterized by X-ray diffraction, optical microscopy (OM) and scanning electron microscopy (SEM). The microhardness, gas permeation tests as well as thermal desorption spectroscopy (TDS) are conducted to evaluate the hardening mechanisms and hydrogen transport parameters. The alloys produced shows enhanced microhardness and hindered hydrogen transport. Therefore, nano-oxide dispersion is such a good strategy for producing advanced materials with superior mechanical and hydrogen-related properties. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Mon, 01 Nov 2021 00:00:00 GMT http://hdl.handle.net/11422/26153 2021-11-01T00:00:00Z