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Análise numérica da influência do tamanho e posicionamento de aberturas adjacentes a pilares de seção quadrada em sistemas estruturais de lajes lisas
(Universidade Federal de São Carlos, 2021-03-01) Küster, Leandro Dias; Almeida Filho, Fernando Menezes de; https://lattes.cnpq.br/0447825383222965; https://lattes.cnpq.br/0718993595233743
The objective of the work was the theoretical and numerical study of the structural behavior of the reinforced concrete slab-column connection for models with different dimensions and opening positions close to the column. A wide bibliographic review on the subject was carried out, raising topics related to structural behavior, tests, numerical simulations and models of rupture load prediction. The methodology used consisted of calibrating a numerical reference model and subsequently a parametric study was carried out addressing the dimensions and positions of openings in a reference model, using the ABAQUS® software. In the numerical simulation it was verified the importance in the dilation angle, viscosity and refinement of the mesh to understand the structural behavior. It was also identified that the test conditions adopted directly interfere in the numerical response, which makes a standard test model necessary. Regarding the parametric study, it was identified that openings located at the edge of the column are more harmful to the slab than openings located at the apex. Regarding the position of the opening, it is clear that the closer to the column, the greater its effect in reducing the model's resistant capacity of the slab. Regarding the size of the opening, it was possible to notice that it has no direct relationship with the reduction of the load capacity. Regarding theoretical models, the Fib Model Code (2010) was the one that came closest to the numerical results, with adaptations being proposed in the normative equations of the codes NBR 6118 (ABNT, 2014), ACI 318 (2019) and Eurocode 2 (2004) for approximation of results. Finally, it was found that openings located from the pillar 3d do not significantly interfere with the structural behavior, however, there is a need to continue the parametric study to better understand the puncture phenomenon and the need for a standard test to better compare the results of different authors.
Síntese de Mg2NiH4 para armazenagem de hidrogênio em compósito polimérico
(Universidade Federal de São Carlos, 2021-03-01) Matheus, Felipe Henrique; Oliveira, Verona Biancardi; https://lattes.cnpq.br/6209504580928538; Leiva, Daniel Rodrigo; https://lattes.cnpq.br/6576844591900987; https://lattes.cnpq.br/1920657495546869
In this work, powder production routes based on Mg2NiH4 are investigated, utilizing high-energy reactive milling; thermal treatment procedures, and hydrogen absorption/desorption cycles, which promote controlled decrepitation, capable of storing and releasing hydrogen at 250 °C, maintaining a high absorption capacity. This material was utilized to obtain a Mg2NiH4-PMMA metal-polymer composite with a maximum work temperature of 250 °C due to possible degradation of PMMA at higher temperatures. The production of this composite aims to create a protective barrier with the polymer, blocking contaminants such as O2 e H2O presents in the atmosphere. The composite production routes were investigated, using high-energy reactive milling with and without the addition of THF solvent. It was verified that the high-energy reactive milling, followed by thermal treatment procedures and controlled decrepitation, can be utilized to produce Mg2NiH4 with the desired properties. Using these techniques, a material based on Mg2NiH4 was obtained with an absorption capacity of 3.5 wt. % at 300 °C and 3 wt. % at 250 °C and with good hydrogen absorption kinetics, reaching absorption plateaus in less than a minute in some cases, so this route was considered ideal to the production of the storage metallic material to be utilized in the metal-polymer composite. However, the results from the production of storage metal-polymer composites by the milling techniques are inconclusive, indicating that more studies are necessary to evaluate these production techniques.
Coalizões no subsistema da política do acordo de Associação Mercosul-União Europeia
(Universidade Federal de São Carlos, 2021-03-01) Grego, Letícia Bernardes de Mello; Capella, Ana Cláudia Niedhardt; https://lattes.cnpq.br/5810332148425938; https://lattes.cnpq.br/5056449990631186
The Mercosur - European Union Association Agreement was finalized in June 2019, after approximately 20 years of negotiation. The member countries and other actors had divergent interests and expressed their opposition or support to the agreement under various arguments, while protectionism of the agricultural sector of the European Union was the most prominent justification among the opponents. While some actors stand out for how they emphasized their position, it is unclear which coalitions are behind the forces that guided the negotiations and which actors took part in them. The Advocacy Coalition Framework (ACF) offers the theoretical basis for the study of coalitions, which is a way for individuals and organizations to join their resources and knowledge in order to imprint their preferences in public policies. This work had the objective of identifying the coalitions of the subsystem of the negotiations of the Mercosur-European Union Association Agreement between 2010 and 2019, by verifying the presence of the two minimum attributes of a coalition, according to Weible et al. (2019): the presence of actors who constantly tried to influence the outcome of the policy and shared policy-core beliefs. Process tracing was used to validate hypotheses formulated about which main state actors shared policy-core beliefs. A coalition between France, Ireland and Belgium was identified in advocacy of higher protectionism of the EU agricultural from 2010 to 2019. These same states formed a coalition that demanded stricter environmental protection policies from the signatories as a condition of the Agreement in 2019. Brazil, Spain and Uruguay formed a coalition in support of trade liberalization between the blocs, of which Paraguay has been a part since 2015.
Eletrodo de pasta de carbono modificado com solvente eutético profundo hidrofóbico e sua aplicação voltamétrica
(Universidade Federal de São Carlos, 2021-03-01) Augusto, Karen Kenlderi de Lima; Fatibello Filho, Orlando; https://lattes.cnpq.br/9859737944357808; https://lattes.cnpq.br/7421215665128985
In this work, the use of hydrophobic deep eutectic solvent was proposed for the modification of carbon paste electrodes. Different HDES were prepared using fatty acids: octanoic, decanoic, and dodecanoic acids, and tetrabutylammonium bromide, and 1-octanol. The electrical conductivities and the water content of these HDES were determined, and the HDES and their precursors were characterized by FTIR(ATR). The HDES TBABr:DecA (1:2 mol/mol) showed better electroanalytical performance in modifying the proposed electrode, therefore was selected as a modifier/ binder in the preparation of carbon pastes. The modified electrode was morphologically characterized and, it was observed changes in its morphology resulting from the incorporation of HDES in the carbon paste. The electroanalytical performance of the electrodes was evaluated and characterized using cyclic and square wave voltammetry. Moreover, electrochemical impedance spectroscopy studies were carried out using hydroquinone as the electrochemical probe. Studies were carried out to optimize the amount of HDES in the pastes, pH, support electrolyte type, and instrumental parameters of the square wave voltammetry technique. In studies by electrochemical impedance spectroscopy, lower values of Rct (322 Ω), and higher values of k0 e kapp, 1.42×10-4 cm s-1e 1.65×10- 4 cm s-1, respectively, were obtained for the modified electrode. Using square wave voltammetry technique, the analytical curve for hydroquinone was linear in the concentration range of 1.50×10-5 to 2.04×10-3 mol L-1, with limits of detection and quantification of 4.59×10-6 mol L-1 and 1.53×10-5 mol L-1, respectively. In repeatability studies (inter and intra-days) and, potential interference, the proposed method showed to be precise and selective. The accuracy of the proposed method was evaluated by determining hydroquinone in dermatologic creams. The results were compared with those obtained using the comparative method by UV-Vis spectrophotometry.
Imagens espectrais do processo de agregação da insulina por complexos metálicos luminescentes
(Universidade Federal de São Carlos, 2021-03-01) Pereira, Lorena Maria Borges; Carlos, Rose Maria; https://lattes.cnpq.br/1589143355309943; https://lattes.cnpq.br/7446682563393163
Insulin is a protein hormone synthesized by β cells in the pancreas, which regulates the level of glucose in the blood. This protein was the first biopharmaceutical produced on an industrial scale for the treatment of diabetic patients. However, the formation of amyloid insulin aggregates is one of the most common and problematic processes found during the production, storage and distribution of drugs based on this hormone, since this process reduces the effectiveness of drugs and, consequently, limits treatment of diabetic patients. The present work aims to monitor in vitro the process of aggregation of bovine insulin using the cis- [Ru (phen)2(3,4-Apy) 2]2+ complex as a luminescent probe. The complex has an intense absorption band in the ultraviolet region (λmax = 260 nm, ε = 70 200 mol-1.L.cm-1) typical of the transitions of unsaturated aromatic ligands (ILCT) and a wide absorption band in the region visible (λmax = 440 nm, ε = 9 650 mol-1.L.cm-1) attributed to the charge transfer transition from metal to ligand (MLCT, Ru, dπ → phen, π*). The complex has a maximum emission at 655 nm, after being excited at 480 nm, an emission lifetime (em) of 60.88 and 0.594 ns in phosphate buffer pH 7.0, with a Stokes shift of around 4 800 cm-1. These spectroscopic properties indicate the potential of this complex for application as a luminescent probe in a biological environment. The insulin aggregation process was investigated as a function of the incubation time, in the absence and presence of the cis-[Ru(phen)2(3,4-Apy)2]2+ complex. From the luminescence assays it was possible to observe that the complex can monitor the insulin aggregation kinetics. The limit for insulin fiber detection was 0.85 M. This low detection limit value indicates that the complex is efficient in detecting amyloid species. The interaction affinity of the complex with the amyloid fibrils was evaluated through the dissociation constant (Kd), the calculated Kd value corresponds to 13.50 ± 1.84 M. The stoichiometry of the ligand between complex and fibers was determined as 1 complex: 2 insulin fibers. Fluorescence microscopy images indicate that it can act as an amyloid marker. Based on these results, it can be concluded that the complex can act as an amyloid marker in the insulin aggregation process.