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Learning trajectories visualizations of visual programming on the computational thinking context
(Universidade Federal de São Carlos, 2020-05-29) Vieira, José Michel Fogaça; Zaina, Luciana Aparecida Martinez; https://lattes.cnpq.br/0192085115595443; https://lattes.cnpq.br/8526887772689607
The ever growing importance of computers and their use created a need for the teaching of computational thinking. In order to better analyze the learning process of the students, teachers and researches often resort to alternative ways of teaching and analysis like visual programming and learning trajectories. Learning trajectories are the steps or paths the students follow as they learn. The task of analyzing the learning trajectories falls upon the area of information visualization. This field of knowledge and research aims to present and extract meaning by creating visual representations of data, the so called visualizations. In this context, this work objective is to propose new literature based and interactive intensive visualizations to represent learning trajectories in order to further enhance the computational thinking learning process by helping teachers to analyze student's learning trajectories. A usability evaluation was conducted with the participation of 23 elementary school teachers and gathered their understanding and feedback in order to assess the usability, acceptance, effectiveness and expressiveness of the proposed visualizations with good overall results. This study contributions besides the proposed visualizations include a new way of organizing visualizations based on layers of representational and interaction aspects and the knowledge gathered about what seems to increase the effectiveness of the visualizations according to the educators perspective.
Estudo do crescimento de nanocristais de TiO2
(Universidade Federal de São Carlos, 2020-05-29) Moura, Bruno Rodrigues de; Leite, Edson Roberto; https://lattes.cnpq.br/1025598529469393; https://lattes.cnpq.br/6463354407273176
STUDY GROWTH OF TiO2 NANOCRYSTALS In the last three decades, the development of nanotechnology has become a reality in many areas of industry and science, already reaching applications in society in sectors such as: health, information technology, transport, energy, food security and the environment. Despite all the research work already done, there are still gaps, mainly in the process of growth and morphology of nanocrystals. Such knowledge is essential for the nanostructures to present the expected gains in optical, mechanical, electrical and magnetic properties, such characteristics are directly dependent on the shape and size of the nanostructures. The processes of nucleation and crystal growth have been studied since the beginning of the 20th century, with the most accepted mechanism for explaining this phenomenon the Ostwald ripening process, where the largest particles grow at the expense of the smallest ones. However, this proposed model does not explain the growth observed in many nanocrystal syntheses. In 1998, Penn and Banfield, proposed a new growth model called oriented attachement, where growth is described as a kind of self-assembly of close crystals when the collision occurs between the faces of these crystals, being these on the same crystallographic orientation. Since then, much effort has been made to better understand the oriented attachment mechanism. In this context, the objective of this work was to study and control the growth process of nanocrystals, using TiO2 nanocrystals as a model, employing a solvent-controlled solvothermal synthesis route, using a titanium alkoxide and oleic acid as a precursor for obtaining nanocrystals. Parameters such as concentration and synthesis time were evaluated, using the techniques of characterization of transmission electron microscopy, x-ray diffraction and thermogravimetric analysis to evaluate the results. The hypothesis that led this study was to verify whether it is possible to grow nanocrystals outside the reaction medium of synthesis. In this work, the results achieved will be presented, with emphasis on the influence of morphology on the stability of TiO2 nanocrystals when exposed to radiation, the growth observed by side-by-side oriented attachment and the growth of nanocrystals after the reaction step in reaction medium different from the initial.
Rotas verdes para obtenção de nanocelulose em biorrefinarias: desenvolvimento de estratégias via hidrólise enzimática e com ácidos orgânicos
(Universidade Federal de São Carlos, 2020-05-29) Bondancia, Thalita Jessika; Farinas, Cristiane Sanchez; https://lattes.cnpq.br/9933650905615452; https://lattes.cnpq.br/1654721179575206
The growing demand for materials from sustainable sources with potential to replace petroleum-based polymers in technological applications projects lignocellulosic biomass as a promising raw material. In this context, nanocellulose has attracted interest due to its numerous properties and functionalities. In this work, different green routes associated with the concept of biorefinery to obtain cellulose nanocrystals (NCC) and cellulose nanofibrils (NFC) in biorefineries were studied. Initially, the use of different enzymatic cocktails was investigated obtain nanocellulose from eucalyptus cellulose pulp (model material) were evaluated. The results showed that cocktails with greater activity of the enzymes xylanases and endoglucanases favored the achievement of more uniform nanometric structures. In contrast, higher glucose release was reached when the enzymatic hydrolysis was performed by complexes containing the class of polysaccharide lytic monoxygenase enzymes (LPMO), which also resulted in nanostructures with higher crystallinity levels. Another method evaluated for nanocellulose extraction was the hydrolysis with citric acid, an organic acid that can be obtained in a biorefinery concept. This approach resulted in a single-step extraction and esterification of the nanocelluloses. Also, the charged surface groups of these nanomaterials improved the colloidal stability of the suspensions in aqueous medium. Another advantage of this method was the higher thermal stability of these nanomaterials compared to those obtained by using sulfuric acid. Based on these results, the use of the enzymatic route and citric acid for sugarcane bagasse was evaluated. Initially, study involved hydrothermal treatment, organosolv followed by the sugarcane bagasse bleaching by a mixture of hydrogen peroxide and sodium hydroxide. After these treatments, the bagasse was hydrolyzed by a commercial cellulolytic cocktail in order to obtain the glucose release integrated with the production of nanostructures. The subsequent study involved the enzymatic hydrolysis of the pre-treated bagasse by the hydrothermal process, which after the release of fermentable sugars was treated by the organosolve method and successively bleached submitted. The bleached residual material was then submitted to three different acid treatments: sulfuric acid, citric acid and a mixture of both acids. In both studies, after the organosolv treatment, 55.8% of the residual lignin was recovered with the potential to be used in other applications. The enzymatic route allowed the obtention of nanostructures with high thermal stability associated with a high glucose release, which can be used in the production of ethanol, organic acids and other bioproducts. The extraction by citric acid and by using a mixture of acids resulted in a nanocellulose with high thermal stability and good colloidal stability, attributed to the presence of charged functional groups on the material surface. In addition, all methods resulted in nanocellulosic materials with a high crystallinity index. Finally, the results here obtained by using different green routes for nanocellulose production may contribute to the selection of the method according to the desired application, in order to add value to the biorefineries residues.
Symmetric and non-symmetric Jack Functions
(Universidade Federal de São Carlos, 2020-05-29) Hindi, Felipe de Mattos Chafik; Schützer, Waldeck; https://lattes.cnpq.br/8638200922501477; https://lattes.cnpq.br/9184090304582276
The goal of this dissertation is to present the theory of Jack functions from the standpoint of algebraic combinatorics. The presentation of symmetric functions is largely centred on the first chapter of MacDonald's "Symmetric Functions and Hall's Polynomials" [7]. Symmetric and non-symmetric Jack functions are characterized by Sahi-Knop's [4] combinatorial formulas. Moreover, Stanley's Pieri-type rule [15] for symmetric Jack functions and Schützer's [13] Pieri-type rule for non-symmetric functions are thoroughly described.
Production, soil amendment and sustainability of sugarcane trash biochar
(Universidade Federal de São Carlos, 2020-05-29) Nakashima, Gabriela Tami; Yamamoto, Hiroyuki; https://lattes.cnpq.br/7817296537223703; Yamaji, Fábio Minoru; https://lattes.cnpq.br/4787449634914831; https://lattes.cnpq.br/6568518277464223
In the past, sugarcane was harvested manually with the aid of fire to facilitate cutting. And because of the Law of the State of São Paulo n. 11,241, which establishes the end of the use of the burning, the sugarcane trash that was previously burned, today is a residue in the plantations. To add value and give a better destination to this residue, some alternatives for its use as raw material are studied. Biochar is a product of pyrolysis of biomass, rich in carbon, which has qualities as a soil conditioner. Therefore, the objectives of this thesis were: to verify the best conditions (pyrolysis temperature and residence time) for biochar production of sugarcane straw and its characterization (Chapter 2), how the biodegradation of this biochar influences for carbon sequestration (Chapter 3) and check the development of sugarcane seedlings with the addition of percentages of biochar in soil (Chapter 4). To verify the best conditions for biochar production (Chapter 2), 6 treatments with 3 different pyrolysis temperatures and 2 residence times were chosen: 200 °C - 2 hours, 200 °C - 4 hours, 325 °C - 2 hours, 325 °C - 4 hours, 450 °C - 2 hours, 450 ° C - 4 hours. The treatments were submitted to proximate analysis, gravimetric yield, porosity, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy analysis (FTIR), X-ray diffraction analysis (XRD) and hydrophobicity test. For biochar biodegradation (Chapter 3), the treatments were: sugarcane straw in natura, 200 °C - 2 hours, 325 °C - 2 hours, 450 °C - 2 hours. These biochars were characterized by their elemental composition (C - carbon, H - hydrogen, N - nitrogen). The biochar (6.3 g/flask) was incubated in 4 flasks by treatment with characterized soil. The quantification of the gases (CH4, CO2, NO2) was performed to verify the influence of biochar on carbon sequestration will occur in a period of 85 days, one sampling per week. For pot experiment (Chapter 4), the biochar produced at 330 °C - 1 hour was mixed to the soil in different application rates: 0 t ha- 1, 1 t ha-1, 5 t ha-1, 15 t ha-1, 30 t ha-1. It was installed 15 plots per dosage/treatment, totalizing 150 plants. Height and diameter measurements were collected every 20 days for 257 days. At the end of the pot experiment it was obtained the dry mass of the aerial part and roots. The soil used was analyzed chemically before and after the pot experiment. The results of the characterization of the biochar produced by Chapter 2, showed that the pyrolysis temperature was a factor that has more influence on the final characteristics of the biochar than the residence time. In Chapter 3, it was observed that the highest rates of greenhouse gas (GHG) emissions were released by treatments with in natura and with biochar 200 ° C, with treatments at 325 °C and 450 °C being more stable and resistant to biodegradation. In Chapter 4, the incorporation of biochar did not result in improvements in the growth of sugarcane but did influence the increase in the pH of the soil. In general, the 325 °C biochar with 2 hours of residence time showed enough results for its application to the soil. Biochar has also proved to be a viable alternative for reducing GHG emissions.