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Propriedades ópticas e magneto-ópticas de monocamadas de dicalcogenetos de metais de transição
(Universidade Federal de São Carlos, 2022-06-07) Soares Covre, Felipe; Matos, Christiano José Santiago de; https://lattes.cnpq.br/6843256597783676; Gobato, Yara Galvão; https://lattes.cnpq.br/7558531056409406; https://lattes.cnpq.br/0605656438457962
Bidimensional (2D) materials are systems of great interest both from the fundamental physical point of view and for possible applications in electronics, optoelectronics and spintronics. In this thesis, the optical properties of monolayers of transition metal dicalcogenetes (TMD) grown by Chemical Vapor Deposition (CVD) and exfoliated were investigated. In particular, we conducted a systematic study of the optical properties of tungsten disulfide (WS2) of large area (of the order of some cm), grown by van der Waals epitaxy on a CVD system. We investigated the optical properties of these samples using macro-photoluminescence and micro-photoluminescence techniques at low temperatures. We observed that the optical emission of these samples is quite unstable in time and that this optical instability depends on the temperature and power of the laser. This effect was associated with photo-induced doping. In addition, we observed thin peaks in the region of lower energy that are promising candidates for the generation of single photons. In general, the results obtained help to gain a greater understanding of the effects of photo-doping dynamics on these systems, which is important for future applications of TMD-based devices. We also investigated biaxial stress effects on a monolayer of molybdenum diselenide (MoSe2)/h-BN prepared by mechanical exfoliation and dry transfer technique. The sample studied has a region with a bubble of the order of 15 micrometers producing a mechanical biaxial tension of up to 1.3% in that region. We investigated the effects of tension using several experimental techniques, such as PL, magneto-PL and second harmonic generation (HGS). The results obtained showed the presence of a non-uniform tension in the sample, as well as a displacement to red in the PL peaks of the exciton and trion, when compared with the region without tension in the sample. A decrease of the trion binding energy and an increase in the g-factor of the trion and exciton in the bubble region were also observed. The results obtained are consistent with calculations of first principles performed in these systems. The results obtained present valuable information on stress effects in the properties of excitons and trions in MoSe2 monolayer and are interesting for the development of devices with controlled mechanical tension based on TMDs.
Análise da adoção de tecnologias da Indústria 4.0 por pequenas e médias empresas do setor de usinagem
(Universidade Federal de São Carlos, 2022-06-07) Baio Junior, Antonio Arnaldo; Carrer, Marcelo José; https://lattes.cnpq.br/6178330814144839; https://lattes.cnpq.br/5256052044490554
New information and communication technologies (ICTs), such as internet of things, wireless network sensors, mobile internet, big data, cloud computing, embedded systems, additive manufacturing and autonomous robots have been adopted by companies from different industries. This movement is treated in the literature as a fourth technological revolution, also known as “Industry 4.0”. Despite the economic, social and environmental potential benefits of Industry 4.0 technologies, the level of adoption by small and medium-sized Brazilian companies still appears to be low. This work aimed to analyze the level of adoption and compare characteristics of adopters and non-adopters of Industry 4.0 technologies. Primary data for the year 2021 were collected through a structured questionnaire applied to a sample of 30 small and medium-sized companies in the metallurgical sector, which operate with machining processes, in the state of São Paulo. Data were analyzed using descriptive statistics measures, statistical tests to compare means/frequency and an econometric regression model. The 4.0 technologies adopted by the sample companies were: Cloud Computing (10 companies), Horizontal and Vertical Integration Systems (5 companies), Big Data (4 companies) and Industrial Internet of Things (4 companies). The comparative analysis between the characteristics of adopters and non-adopters showed that: (1) adopters have, much more frequently, employees with ICT skills and also more frequently hire ICT consulting services; (2) the use of ERP and MRP systems is much higher among companies adopting Industry 4.0 technologies; (3) adopters participate more frequently in cooperation programs with Universities, Science and Technology Institutes or Technological Research and Development Promotion Agencies; (4) companies that adopt 4.0 technologies have a greater perception of relative advantage and compatibility of these technologies. The results of the estimated econometric model corroborate the importance of the availability of skilled labor in ICTs, the prior adoption of other management technologies and the perception of compatibility of 4.0 technologies to determine the intensity in use of these technologies by the companies in the sample. The study results are consistent with the empirical literature review and with the theoretical TOE model.
Saberes de diretores sobre as dimensões da administração escolar
(Universidade Federal de São Carlos, 2022-06-07) Silva, Caroline Miranda Palmieri da; Luiz, Maria Cecília; https://lattes.cnpq.br/7425361719028650; https://lattes.cnpq.br/2328230255840992
This study aimed to analyze the relationship with Knowledge, according to Bernard Charlot, of school directors according to the school administration model of Benno Sander (2007), with the economic, pedagogical, political and cultural dimensions. Data were collected in 2021, through two instruments: a closed questionnaire, in a stratified sample, composed of 2882 Brazilian directors and a focus group with five mentor directors (representing the five regions of Brazil) who participated in the Mentoring Improvement Course of School Directors offered by the Federal University of São Carlos (UFSCar). There was an intertwining between the relationship with the Knowledge of the five directors and the dimensions of Sander (2007), especially, the Knowing how to do and the relational Knowledge. The directors respond to the extent of what they experience and to analyze the relationship of a subject with Knowledge is to understand the epistemic, social and identity relationships of this being immersed in the learning process, and these dimensions are not fragmented in this process. Future studies are indicated in order to closely monitor the management of these directors in different regions of Brazil, mainly due to the diversity of Brazilian schools. It is concluded that, in Brazil, public policies need to promote democratic management, instituting forms of entry into management positions through democratic means, both in secretariats and in institutions, since it is essential that these directors can be legitimate representatives in the fight for a quality education, in addition to having more spaces in which debates take place in municipal, state and federal instances, in which more democratic and legitimate discussions are held, with the intention of thinking about a different school from the one we have today.
Fenomenismo no Quarto Paralogismo da Crítica da Razão Pura de I. Kant: a leitura berkeleyana do idealismo transcendental
(Universidade Federal de São Carlos, 2022-06-07) Garcia, Ernane São João; Baioni, José Eduardo Marques; https://lattes.cnpq.br/9613180348313909; https://lattes.cnpq.br/8150590189872500
The philosophies of Kant and Berkeley aim to refute skepticism and, for this purpose, they defend the thesis according to which the objects of our knowledge are, respectively, “representations” or “ideas”. In general, this thesis is classified in the literature as “phenomenism”. Such similarity between the position of both philosophers has led many critics to see the position of Immanuel Kant in the Fourth Paralogism of the first edition of the Critique of Pure Reason (1781), a passage in which the philosopher intends to refute the “empirical idealism”, as being identical to that of the philosopher George Berkeley in the Principles (1710) and the Dialogues (1713). This reading, defended, among others, by Norman Kemp Smith, Colin M. Turbayne and James Van Cleve, conflicts with two assertions by Kant: that his transcendental idealism is “the opposite” of Berkeley's and that the Fourth Paralogism differs from the Refutation of Idealism of the second edition of the first Critique only in the way of proving. Against this Berkeleyan reading of the Fourth Paralogism, we argue that Kant's position in this passage is fundamentally different from Berkeley's. To prove our thesis, we try to determine the nature of Berkeleyan phenomenism, which was determined as an ontological phenomenism, and then to verify if Kantian phenomenism is identical to that. This was possible by the application of the distinction, presented by Kant in the Fourth Paralogism, according to which objects can be considered in two senses, the empirical and the transcendental, to the Kantian notion of “representation”, which allowed us to determine whether the Kantian concept of “representation” is or is not equivalent to the Berkeleyan concept of “idea”. As a result, we show that the Kantian conception of “representation” is radically new in the light of the philosophical tradition and that Kant's phenomenalism is an epistemic phenomenalism, being, therefore, radically different from Berkeley's ontological phenomenalism, which allows us to resolve the two problems outlined.