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Dopagem substitucional de peroviskitas com metais de transição 3d: um estudo ab initio
(Universidade Federal de São Carlos, 2022-10-04) Chagas, Lucas Guilherme; Lima, Matheus Paes; https://lattes.cnpq.br/1835846543912999; https://lattes.cnpq.br/0907339374208991
The global demand for energy has brought into focus the halide perovskites as materials with high potential for applications in photovoltaic devices. Great progress has been made in the last 10 years, demonstrating the possibility of surpassing the efficiency of current silicon-based technology with the advantage of lower costs and ease of synthesis. However, there are two drawbacks for its large-scale commercial use: (i) the most efficient perovskites currently have lead in their composition, generating strong toxicity; (ii) in addition, there is structural instability, resulting in degradation, and consequent loss of its properties. This degradation can lead to the release of lead, and is greater in the case of perovskites with organic cations. As an alternative, perovskites with inorganic cations, such as Cs + , have been explored. It is also common to replace lead with non-toxic metallic cations, such as Sn 2+ . In particular, CsSnI3 is a promising lead-free perovskite for applications in photovoltaic devices. However, this material has two phases at room temperature: Black (photo-active) and Yellow (photo-inactive), the second being more stable, but without potential for applications in photovoltaic devices due to its wide bandgap (2,4 eV ). In this work, we study the substitutional doping of CsSnI 3 with transition metals 3d at the site of Sn through simulations ab initio based on density functional theory. The dopants are Sc , Ti , V , Cr , Mn , Fe , Co , Ni , Cu , and Zn . The study was divided into three stages: (i) study of CsSnI3 without defects; (ii) doping 100% to understand the limits of high concentration; (iii) partial doping in concentration of 12,5%. The results of step (i) indicate that the Yellow phase is more stable than the Black phase, and that local structural distortions are essential to obtain a bandgap in agreement with experimental data. Step (ii) indicated that dopants in high concentrations can improve the stability of CsSnI3 . Step (iii) shows that there is a reduction of the lattice parameter for dopings with Sc , V , Cr and Mn . However, some dopants induce Jahn-Teller distortions in octahedra, namely, Co , Ni , Cu and Zn . The calculation of the energy of formation shows that the doping with Sc is exothermic, while the others are endothermic. Most defects have the most stable neutral state of charge. The only exceptions are doping with Ni and Cu . Furthermore, the dopants V , Cr , Fe and Co introduce states into the bandgap. Finally, our most relevant result was the inversion of the most stable phase for dopants with a greater number of electrons 3d. That is, the black phase is more stable when we doped CsSnI3 with Co , Ni , Cu , and Zn . Our work demonstrated that the stability of perovskites can be controlled with substitutional doping, and indicated the main effects of this doping on the structural and electronic properties of CsSnI3.
Um estudo dos modelos de sobrevivência de longa duração LIGcr e GEPGWcr
(Universidade Federal de São Carlos, 2022-10-04) Stella, Caroline Amantea; Suzuki, Adriano Kamimura; https://lattes.cnpq.br/4579497412852854; https://lattes.cnpq.br/9914440896089821
In this work we study two long-term survival models denomined Logaritmic Inverse Gaussian cure rate (LIGcr) model and Geometric Exponentiated Power Generalized Weibull cure rate (GEPGWcr) model. Both models take into account the existence of unobserved heterogeneity. For this, both models consider a random variable that describes the frailty been discret and starting on zero. For both models studied, the parameters are estimated by the maximum likehood method. In a simulations study, we investigated the averages of the estimates, the biases, the mean squared errors and coverage probabilities. Finally, we show the applicability of the models to real data sets.
Desafios e possibilidades da atuação de intérpretes educacionais para a inclusão de alunos surdos na educação básica
(Universidade Federal de São Carlos, 2022-10-04) Silva, Luiza Trindade da; Martins, Vanessa Regina de Oliveira; https://lattes.cnpq.br/4768682330164550; https://lattes.cnpq.br/2267183017660362
The present work shares the analyzes carried out from the research of the Course Completion Work (TCC) of the Bachelor's Degree in Translation and Interpretation in Libras/Portuguese Language. The research aimed to investigate the dilemmas and possibilities of the performance of educational interpreters in the early and final years of elementary school, bringing considerations of the inclusion of deaf students in basic education and its impact on the training of translators and interpreters of Libras. The research problematized the dilemmas of this process for 3 aspects: 1) the performance of the educational interpreter, demarcating his function in the face of the articulated relations between the regent teacher and the Educational Interpreter (EI), 2) the challenges and possibilities for the performance of the EI in basic education and 3) the dilemmas and creation of strategies for interaction with deaf teachers and students at school. In order to answer these questions, a bibliographical survey of research was carried out that underlies the current dilemmas of deaf education and the presence of translators and interpreters as mediation agents between teachers, deaf students and the school context. For data collection, interviews were conducted with 2 professional educational interpreters who work or have worked in interpretive mediation for the deaf in basic education, focusing on basic education. It is expected that such knowledge can directly help in the formation of EI and in its interpretative and educational practices with deaf students in the context of school inclusion.
Dinâmicas de gênero no parlamento das águas: o caso do Comitê de bacia Rio Pardo (SP)
(Universidade Federal de São Carlos, 2022-10-04) Souza, Janaina dos Santos de; Martins, Rodrigo Constante; https://lattes.cnpq.br/6617183095074852; https://lattes.cnpq.br/2687747073551813
This work focused on analyzing the conflicts and dynamics of gender relations in the water parliament, more specifically in the management unit of the Rio Pardo Basin Committee (CBH-Pardo), which is a fundamental space in terms of the economy paulista, mainly due to sugarcane monoculture activities. Considering the participatory character proposed by this governance model, we seek to understand the participation of women in this management instance from its first management team, started in 1996, until the management of the year 2019, also highlighting the plenary with the right to vote. It is important to emphasize that this analysis did not take place only in terms of the number these women, but in the participatory quality and in the way of their insertion in the internal organizational structures of the committee. We work with the hypothesis that the governance structure of São Paulo waters, more specifically the CBH-Pardo, reproduces an organizational model that generates different types of conflicts and gender dynamics, which are the result of tensions of a power legitimized through of central forces in the field of technical-scientific knowledge and the market. A qualitative approach of social research was used in the research, through bibliographic research, survey and document analysis, as well as semi-structured and in-depth interviews with the participating members of the Committee. From this we can highlight two important results of the research carried out: the first one that is guided by a reorganization of our original hypothesis, showing that this space not only showed us models and gender conflicts, but also presented us with the democratic limits of the formation of the committee , which did not overcome traditional and social values; and the second one that properly refers to the scope of power relations and how these are placed in the path of a participatory parity look, outlining the central and peripheral relations that design the participation of these women .