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Propriedades e aplicações de revestimentos de óxidos metálicos obtidos por oxidação eletrolítica a plasma e dopagem anódica utilizando resíduo de lama vermelha
(Universidade Federal de São Carlos, 2023-06-28) Araújo, Patrícia dos Santos; Mendonça, Vagner Romito de; https://lattes.cnpq.br/4270375873948823; https://orcid.org/0000-0003-2300-9959; Trivinho-Strixino, Francisco; https://lattes.cnpq.br/9740223649776400; https://orcid.org/0000-0002-0990-0270; https://lattes.cnpq.br/0941361933718898; https://orcid.org/0000-0002-3418-1407
Plasma Electrolytic Oxidation (PEO) is a metal processing technique where a high potencial difference is applied between two electrodes, cathode and anode. During this process there is a phenomenon of dielectric breakdown caused when the thickness of the oxide layer that forms reaches a limit and causes micro discharges to appear throughout the surface of the material that sinter and crystallize the formed oxide adhered to the substrate. The oxide layer produced under these conditions can have characteristics such as high mechanical strength or photoactivity. Processing conditions, such as composition, concentration or temperature of the electrolyte used during the formation of coatings, affect the composition and morphology of the produced coatings, altering their properties. This work presents results of the process of surface treatment of Niobium metal under PEO conditions, using a system consisting of a direct current source in galvanostatic regime and temperature control of the electrolyte. The photocatalytic properties of the coatings are also observed. The work can be divided into three parts: 1) investigation of the influence of different electrolytes on the anodizing curve of the synthesis of Nb2O5 coatings. Niobium substrates after anodization in acid medium (C2H2O4 and H3PO4) and basic medium (KOH) were characterized and tested for photoactivity; 2) investigation of the insertion of different amounts in mass percentage of Red Mud in C2H2O4 solution, during the anodizing process. Red Mud is an alkaline residue from the aluminium industry and was used as a dopant; 3) the study of the temperature and composition of the electrolytes in the oscillations of potential and photoactivity of the coatings. In this step, the temperature variation of the electrolyte in the synthesis of the coatings was investigated using different compositions of electrolytes (C2H2O4 at 2 and 25°C, H3PO4 at 15 and 30 °C, KOH at 15 and 25°C and C2H2O4+1% of mud at 15 and 25°C). The samples were characterized by techniques such as scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS). The photocatalytic efficiency was investigated using photodegradation tests in a UV camera with samples in contact with an aqueous solution of Methylene Blue (MB) and Rhodamine B (RhB). During the synthesis in different types of electrolytes, different behaviour of temperature and voltage curves (V) as a function of charge (C) were observed. As a consequence, the samples presented morphology and varied chemical and structural composition according to the parameters of synthesis and addition of dopant, the samples anodized with electrolyte containing 0.1 mol.L-1 solution of C2H2O4 and addition of sludge up to 0.75% , showed superior photocatalytic efficiency compared to other studied conditions. This result was explained by the characterizations that showed morphology with pores of regular size and shape with distribution over the entire surface, formation of orthorhombic Nb2O5, bang gap estimated between 3.12 to 3.27 eV. After the inclusion of the red mud to the electrolyte, elements such as Al and Si were found in the coatings produced and the doping of a small % of these elements on the surface of the coatings proved to be effective in increasing the degradation rate of the MB dye in the first 60 minutes of the test.
Reflexões e possibilidades sobre a quantificação dos surdos sinalizantes nos levantamentos censitários brasileiros
(Universidade Federal de São Carlos, 2023-06-28) Lima, João Víctor de Araujo; Santos, Lara Ferreira dos; https://lattes.cnpq.br/7312070448044165; https://orcid.org/0000-0002-3196-9346; https://lattes.cnpq.br/1489778587557179; https://orcid.org/0000-0002-6014-2428
Brazilian deaf individuals face a series of challenges in their daily lives, especially regarding the guarantee of their linguistic rights, even after the legal recognition of Brazilian Sign Language in 2002. A relevant aspect to be considered is how they are represented in the official statistics of the country's census surveys, which play a fundamental role in the production and monitoring of Brazilian public policies. From this context, the objective of this research was to identify how deaf signers are currently quantified in the statistics of the Brazilian Institute of Geography and Statistics (IBGE) and present possible paths for a dialogue that allows for the inclusion of the demands of deaf social movements in the population statistics research in Brazil. To accomplish this, the study is based on the concept of dual category status of deaf individuals and sign languages, in order to understand the impact of different conceptions of deafness in the census surveys conducted by IBGE, and on the concept of statactivism, through the approach of the sociology of quantification, to facilitate a dialogue between the demands of these movements and the institute. In general, mentions of “deaf individuals” and “sign languages” were analyzed in: 1) Claims made by Brazilian deaf individuals; 2) IBGE statistics, mainly in the Demographic Census and the National Health Survey. In addition, the statistical activism of indigenous peoples in IBGE's statistics was studied, seeking inspiration for Brazilian deaf statactivism. Based on these analyses, the study results indicate that there has been an evolution in the conception of deaf individuals in Brazilian census surveys, but they are still represented solely as people with disabilities. To incorporate the demands of deaf communities into these surveys, national and international partnerships with academics and international organizations responsible for statistical production are essential, incorporating the socio-anthropological perspective on deaf individuals, as well as constant dialogues between deaf representations such as Feneis and the World Federation of the Deaf, and IBGE.
Liderança colaborativa no contexto do trabalho em equipe na atenção primária à saúde: revisão integrativa
(Universidade Federal de São Carlos, 2023-06-28) Caneppele, Juliana Kelly Pascchotto; Rossit, Rosana Aparecida Salvador; https://lattes.cnpq.br/3333865775403342; https://orcid.org/0000-0002-0563-7188; https://lattes.cnpq.br/8303890704717645; https://orcid.org/0000-0002-4198-7644
Teamwork based on collaborative practice is a powerful strategy for tackling the challenges involved in the development of work and caring for growing and complex health demands. Collaborative leadership is essential for involving the different players in discussions and in carrying out activities, so as to respect points of view, value suggestions and proposals, and promote autonomy for team members. With autonomy, team members' sense of belonging reaches a different level, leading to greater engagement among professionals. The aim of this study was to analyse the available scientific evidence on collaborative leadership in teamwork contexts and its contributions to primary health care, highlighting how collaborative leadership occurs in the work context and its possible contributions to health outcomes. This is an integrative review that took up the research question: "How have professionals developed collaborative leadership in the context of teamwork in Primary Health Care?". It included original articles available in full online, in Portuguese, English or Spanish, published between 2017 and 2022. For the searches, the following electronic bibliographic databases were consulted: MEDLINE-PUBMED, ERIC, SCOPUS, WEB OF SCIENCE and Lilacs. The search terms (leadership; collaborative; health; professional; teamwork; interprofessional; interdisciplinary; education; training) were applied in Portuguese, English and Spanish, in different combinations with the booleans "AND" and/or "OR". All the articles identified were saved, exported and hosted on Rayyan®. The eligibility criteria were applied by two independent double-blind evaluators. In total, 3,601 articles were identified. The ckecklist and PRISMA flowchart were followed. After the initial screening of abstracts and titles, 47 articles were selected and read in full. Of these, 27 were eliminated. The 23 articles that met all the eligibility criteria were included in the integrative review. The data was extracted, organised in a summary table and categorised. Four categories emerged from the analyses: Conceptions and Perspectives of Leadership; Characteristics of Leadership Models; Challenges and Possibilities of Collaborative Leadership in Healthcare Organisations; and the Potential of Interprofessional Education for Developing Collaborative Leadership Competence. The results indicate the importance of developing shared leadership competences among healthcare leaders and teams. Shared leadership has the potential to improve the commitment and motivation of professionals; contribute to decision-making and effective communication; and promote the continuous training of leaders to favour mutual recognition. Based on the publications, a framework was organised with competences related to collaborative leadership in health contexts. The need to improve leadership studies is clear, especially considering the perspective of interprofessional collaboration as an alternative to authoritarian and hierarchical management models. Collaborative competences involve a combination of knowledge, skills, attitudes, values and judgements that must be developed or improved in the different contexts of training and working in healthcare, in pursuit of quality care.
Análise numérica da força última e do modo de falha de ligações com cisalhamento duplo em estruturas de madeira
(Universidade Federal de São Carlos, 2023-06-28) Leoni, Vitor Lourensato; Christoforo, André Luis; https://lattes.cnpq.br/7623383075429186; https://orcid.org/0000-0002-4066-080X; https://lattes.cnpq.br/5780893629407978; https://orcid.org/0000-0002-2008-6468
Timber is a material with several benefits for the construction industry because, in addition to being sustainable and renewable, it also possesses favorable properties for use in structures. However, precisely because it is a natural material, the vast number of wood species and their varying mechanical properties pose challenges for research. Consequently, this present study undertook a comprehensive numerical analysis employing the ABAQUS software to investigate some wood species and their performance in structural connections involving metallic pins under double shear conditions. The principal objective of this study was to evaluate the precision of normative equations and pertinent literature. In light of this, regression models were employed to formulate an equation capable of estimating the ultimate strength and failure mode of these connections. Two regression models, characterized by determination coefficients of 95.74% and 91.50% respectively, were successfully derived, clearly illustrating the significant influence of all analyzed parameters on the calculated values of ultimate strength. This approach facilitated a meticulous comparison of the precision exhibited by these parameter equations, effectively identifying any divergences that may exist between the models integrated into normative codes, such as ABNT NBR 7190-1 (2022) and EUROCODE 5 (2004), and the results acquired through this research results. Conspicuous disparities were observed, particularly when contrasting the theoretical outcomes obtained from the Brazilian normative code with all other calculated values. These findings compellingly suggest that the values generated by normative equations are overly cautious in nature.
Métodos Bayesianos para seleção de modelos de mistura de distribuições normais e t de Student assimétricas
(Universidade Federal de São Carlos, 2023-06-28) Macerau, Walkiria Maria de Oliveira; Milan, Luis Aparecido; https://lattes.cnpq.br/7435391829973844; https://orcid.org/0000-0001-6466-7865; https://lattes.cnpq.br/9334093984788993; https://orcid.org/0000-0001-6466-7865
In this work, we consider mixture models whose components of the mixture are modeled by the skew normal and skew t distributions. For the estimation of these skew mixtures models, we used a Bayesian approach, via Markov Chain Monte Carlo methods (MCMC), since this approach allows the development of a joint estimation procedure of the mixture components number and the associated parameters of the mixture components. We also use the Reversible jump method and propose the use of the Data-driven Reversible jump method for modelling the mixture of skew normal and skew t distributions, both to adjust and select the number of components of the mixture. We compare the performances of these two methods (Reversible jump and Data-driven Reversible jump) for selecting the best model through simulations. The Data-driven Reversible jump method was more accurate in pointing out the best model in the simulation studies carried out.
Análise numérica de pilares mistos preenchidos com concreto reciclado sob compressão axial centrada
(Universidade Federal de São Carlos, 2023-06-28) Oliveira, Tawan Mundim de; Nardin, Silvana de; https://lattes.cnpq.br/5587716781980132; https://orcid.org/0000-0002-8736-4987; https://lattes.cnpq.br/1365747842102318; https://orcid.org/0000-0001-5577-6031
Part of the waste generated in civil construction, especially waste concrete, can be used as replacement of natural aggregates. Aiming to expand the use of concrete with recycled aggregates in composite columns, the aim of this study was to evaluate the behavior of composite columns filled with recycled concrete subjected to concentric load. For this, numerical simulation was developed in software Abaqus. First, a systematic review of the literature (SRL) on circular cross-section composite columns filled with recycled concrete was conducted. Most of the available studies are related to experimental results showing an increase in ultimate load due to the use of recycled concrete. Numerical models were developed in software Abaqus® and a sensitivity analysis was conducted to evaluate the influence of parameters such as finite element mesh density, constitutive models of recycled concrete, damage model parameters, steel-concrete friction coefficient, Poisson's ratio and modulus of elasticity of recycled concrete. Among the parameters evaluated, the most significant was the constitutive model of recycled concrete. Compared to experimental results, the numerical model properly predicted the ultimate load capacity, the Load vs. axial strain behavior of the column, and the strains in steel tube and concrete core. The validated numerical model was used to evaluate the influence of steel tube diameter (D=114.3 mm; 219.1 mm and 323.8 mm), height-diameter ratio (L/D=3, 4 and 5); diameter-thickness ratio (D/t=8.4; 18.1 and 28.6) and yield strength of steel (fy=300 MPa and 400 MPa), totaling 54 models. Regarding the ultimate load capacity, decreases were found when D/t went from 8 to 18 and from 18 to 28. There was also an increase in the ultimate load capacity when the yield stress of the steel went from 300 MPa to 400 MPa. Changing the D/t ratio from 8 to 18 was the parameter that most affected the resistant capacity of the column. Finally, there was no significant difference in the strength when the L/D ratio increased from 3 to 5. The values of ultimate load predicted using numerical modelling and Eurocode 4 (EN 1994-1-1:2004) standard procedure were very close each other. Regarding to ABNT NBR 8800 (2008) and AS/NZS 2327 (2016), both standard procedures were conservative with results about 80% of the values from numerical modelling. It is worth noting that these standards do not apply to recycled concrete.
Photocatalytic controlled oxidation reaction of methane
(Universidade Federal de São Carlos, 2023-06-28) Cruz, Jean Castro da; Paris, Elaine Cristina; https://lattes.cnpq.br/8475640212486290; https://orcid.org/0000-0001-8599-9674; Oliveira, Cauê Ribeiro de; https://lattes.cnpq.br/5321313558714462; https://orcid.org/0000-0002-8908-6343; https://lattes.cnpq.br/6346090713548334; https://orcid.org/0000-0001-9428-4304
The CH4 partial oxidation into value-added chemicals by solar means has been discussed as alternative for emission abatement, a fundamental topic for sustainable production with lower global warming gas emissions in future. So far, various semiconductor photocatalysts have been developed. However, the understanding of the main factors influencing photocatalysts' activities on controlled oxidation of methane to methanol is still an issue, especially due to methane overoxidation to CO2. Thus, we propose that the semiconductor must have a valence band (VB) favorable to produce hydroxyl radicals (•OH) and a conduction band (CB) not advantageous to superoxide radical (O2•-). Furthermore, the concentration of the hydroxyl radicals is fundamental and should be fine-tuned for selectively oxidize methane. O2 also is the key oxidant for process control, since O2 may scavenging methyl radicals (•CH3) that further react with •OH to form methanol. Our results showed that the required band edge positions for photocatalysts (e.g., Bi2O3) seems correct to obtain significant amounts of desirable chemical products, taking as main products methanol (3700 μmol g-1) and acetic acid acetic acid (~2036 μmol g-1 h-1) from pure CH4 at room temperature and atmospheric pressure. Moreover, longer hydrocarbons (e.g., ethanol and acetone) could be produced depending on the reaction condition. ESR experiments proved the formation of •CH3 and •OH, and isotope labeling experiment with 13CH4 as the reactant also was conducted, confirming that CH3OH comes from CH4 photooxidation. Another sustainable route to control the CH4 oxidation driven by chloride intermediates in solution using Bismuth-based semiconductors excited in visible light was investigated. BiOCl, a perovskite layered material, exhibited promising photocatalytic performance for methane conversion to methanol (1300 µmol g-1), acetic acid (435 µmol g-1), and ethanol (57 µmol g-1) without foreign radicals to control the reaction. Our findings are significant to new level of understanding in methane’s efficient partial photooxidation, which opens a way to control competitive reactions by appropriate band edge positions in photocatalysts to greater selectivity and avoid its overoxidation to CO2.