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Estudos do reaproveitamento térmico do bagaço de laranja: secagem em leito de jorro modificado e peletização
(Universidade Federal de São Carlos, 2024-03-11) Pinto, Guilherme Henrique Alves; Freire, José Teixeira; https://lattes.cnpq.br/2270677706718167; https://orcid.org/0000-0002-8412-6801; Freire, Fábio Bentes; https://lattes.cnpq.br/8937961078558996; https://orcid.org/0000-0001-9258-360X; https://lattes.cnpq.br/6919620534872525; https://orcid.org/0000-0002-0896-7385
The use of biomass as an alternative source of renewable energy has been gaining ground and leading to innovations in the production sector, seeking to support sustainable development and dispose of waste that was previously discarded. Brazil stands out as one of the world's leading producers of oranges, being the largest exporter of juice. Orange pomace, an abundant by-product with largely untapped potential as a biofuel, requires technical improvements to render its use viable. The present work aimed to evaluate the drying of orange pomace in a spouted bed to obtain dry biomass for pelletization. This evaluation involved studying the influence of a CaO mixture combined with pressing as pre-treatment, assessing the fluid dynamics in both the conventional spouted bed (LJC) and the spouted bed with mechanical agitation (LJMM) equipped with inclined blades, with variations in the bed's static height. Drying experiments were conducted in the LJMM, altering air temperature from 40 to 80 °C and air flow from 1 to 5 times the minimum spout velocity. These variations were analyzed for their impact on drying time and the quality of the resulting pellets. The obtained dry biomass underwent pelletization using three distinct strategies to enhance its physical and mechanical properties: particle size reduction, inclusion of binders, and torrefaction. The pellets were subjected to characterization tests measuring durability, impact resistance, density, water absorption, as well as aging properties such as changes in color, density, and humidity over time. The addition of quicklime with pressing removed 31.7% of the initial moisture from the bagasse, facilitating some movement in the LJC. However, the process faced instability due to biomass cohesion. Mechanical agitation proved essential in enhancing operational stability by agitating the entire bed, increasing stability, and eliminating fines carryover, up to 11.65% for LJC, allowing for a bed height of 27 cm, higher than the maximum 21.1 cm for LJC. Fluid dynamics analysis for the LJMM indicated an increase in pressure drop with rising bed height, while this correlation was absent for the minimum operating speed. This suggested that agitation primarily facilitated particle motion and air movement expanded the bed. The LJMM's operating air velocity was measured at 1.10±0.14 m/s, significantly lower (90%) compared to the minimum spout velocity required for a 21.12 cm height (11.11 m/s). During biomass drying, saturation of moisture in the gas stream at the LJMM exit highlighted efficient energy utilization, signifying an adequate airflow supplied to the system. Temperature and drying air flow showed no significant influence on pellet properties. Pellets produced from dried bagasse failed to attain desired physical and mechanical properties, necessitating particle size reduction to eliminate predetermined fragility points due to coarse particles. Strategies involving the addition of solid carbohydrates and mixing with coffee grounds altered pellet mechanical properties but fell short of achieving desirable values. Torrefaction imparted some hydrophobicity to the biomass, ensuring adequate water absorption, albeit resulting in fragile pellets. The addition of molasses enhanced pellet density and strength, but pellets expanded during a 30-day storage period. However, the addition of pure water or gelatinized starch produced resilient pellets, exhibiting high durability and impact resistance, maintaining structural integrity even after storage. These pellets also met the density threshold of 1200 kg/m³ with minimal color variation. These outcomes underscored the significance of moisture as a binding agent, allowing for the integration of drying and pelletization, ensuring an economically and operationally viable process.
Planificação de superfícies poliédricas no cálculo de distâncias
(Universidade Federal de São Carlos, 2024-03-11) Rosa, Marcus Vinícius Fontes de Aquino; Massago, Sadao; https://lattes.cnpq.br/1915704875970931; https://lattes.cnpq.br/8153087447730131
This work proposes the calculation of the length of the shortest possible trajectory connecting two points on the surface of a straight rectangular parallelepiped. One of the points belongs to a face and the other belongs to another face, adjacent to the first. The initial step of the solution is to identify the minimum trajectory, that is, to know exactly where it passes, and the other is to obtain its measurement. To identify the trajectory, a plan is carried out, so that the two adjacent faces are contained in the same plane. As a resource for calculating the length of this trajectory, this work suggests the Pythagorean Theorem or the Similarity of Triangles as a tool. A mathematical modeling of this problem will be proposed by calculating the shortest length of a conduit running from a lamp on a room's ceiling to the lamp switch on one of the room's walls. The concepts of Plane and Spatial Geometries accessed in the consideration and resolution of the problem are considered and presented, which serves as motivation for teaching and learning such concepts. Other similar situations will be suggested, such as, for example, the measurement of a minimum trajectory traveled on the lateral surface of a straight cylinder.
Análise de agrupamentos para dados espectrais
(Universidade Federal de São Carlos, 2024-03-11) Silva, João Pedro Alvarenga Ramos da; Souza, Camila Pedroso Estevam de; https://lattes.cnpq.br/7665731855194346; Andrade Filho, Mario de Castro; https://lattes.cnpq.br/6518161034709249; https://lattes.cnpq.br/6540913903596103
Spectroscopy is the study that uses techniques to measure the spectrum of electromagnetic radiation, including visible light and radiofrequency, where we search for information such as chemical composition, temperature, density, mass, distance, luminosity, and relative motion using displacement measurements. In the case of Raman spectroscopy, we use a light diffusion process to obtain additional information about vibrations that increase the understanding of the fundamental molecular structure. These methodologies provide a diversity of data, which will be modeled and analyzed using statistical and machine learning techniques. The spectroscopy data show high dimensionality and a strong presence of outliers that cause difficulties in clustering due to false positives in discovering new clusters. For the study, a review of the literature on methods for grouping spectroscopy data that do not vary with time will be made. Thus, comparing models with the existing ones, and applying it to real data and simulated data.
Qualidade de vida, autoeficácia e autoestima de gestantes de baixo risco
(Universidade Federal de São Carlos, 2024-03-11) Mazziero, Patricia Fernanda Evaristo; Salim, Natália Rejane; https://lattes.cnpq.br/1116654985699024; https://orcid.org/0000-0001-7744-8274; Napoleão, Anamaria Alves; https://lattes.cnpq.br/8539664594837249; https://orcid.org/0000-0002-6229-4206; https://lattes.cnpq.br/4682247833450558; https://orcid.org/0009-0002-6746-3459
Pregnancy is a period of intense changes for women, both in their body and in their lives, involving significant physical and hormonal changes. Even in low-risk pregnancies, changes are observed that can impact the quality of life of pregnant women and affect their health and that of the newborn. The way pregnant women experience these changes has repercussions on the formation of their maternity and on their relationship with their child. The self-esteem of the pregnant woman is pointed out in the literature as one of the important factors for bonding with the child, self-efficacy can favor the development of skills and contribute to coping with the alterations. Objective: To evaluate the quality of life of low-risk pregnant women and associations with self-efficacy and self-esteem. Method: This is a descriptive, cross-sectional study with a quantitative approach. It was developed in the city of Mococa-SP, in the primary care services of the municipal health network. The sample consisted of 135 pregnant women at different gestational stages. Pregnant women over 18 years of age and involved in active prenatal care were included. The study was approved by the Human Research Ethics Committee of UFSCar. All ethical principles established in CONEP Resolution No. 510 of April 7, 2016 were followed. The collection period was from July to October 2023. Results: Pregnant women had high levels of general quality of life and satisfaction with health, high levels of self-efficacy and unsatisfactory self-esteem occurred in a high percentage (81%). There was an association with quality of life and self-efficacy (p<0.005) and with sociodemographic and clinical data (p<0.05) in the physical, social relationship and environment domains. There was no association between self-esteem and self-efficacy (p=0.40). Conclusion: Pregnant women in general had adequate levels of quality of life and were satisfied with their health. They also had high self-efficacy, but decreased self-esteem. There are sociodemographic and clinical factors such as being black, having previous abortions, previous vaginal births, previous pregnancies, and having several people living in the house that were associated with certain domains for worse quality of life. The present study may contribute to clinical practice, since it points to the possibility of care focused on the specific needs of this population that go beyond the physical scope. It is suggested that new studies on quality of life, self-efficacy and self-esteem in pregnant women should be carried out, given the scarcity of studies that investigated these variables together and given the relevance of a greater understanding of the factors that influence them, which may favor the production of more robust data and contribute to the quality of care for pregnant women.
Síntese de nanopartículas por métodos microfluídicos
(Universidade Federal de São Carlos, 2024-03-11) Gomes, Nícolas Moreira de Carvalho; Cordeiro, Marco Aurélio Liutheviciene; https://lattes.cnpq.br/4787678071396324; https://orcid.org/0000-0001-6287-3083; https://lattes.cnpq.br/4699827186889924; https://orcid.org/0000-0002-6986-7169; Godinho Junior, Mario; Arantes, Tatiane Moraes; https://lattes.cnpq.br/8364676654739392; https://lattes.cnpq.br/9039822138866007
Obtaining micro and nanoparticles with high structural and chemical control is in great demand given the continuous need to increase the performance of a series of processes and devices. The most common processes for synthesizing nanostructures consist of bottom-up processes, especially for the synthesis of silicon dioxide (SiO2), which are among the metal oxides applied in biomedical areas. Such methods make it possible to obtain particles with monodispersed and particles with nanometric dimensions. To achieve this, the synthesis of nanoparticles must be well controlled with well-defined parameters so that the properties of the final material are not affected. One approach to increasing efficiency in obtaining particles is continuous flow synthesis, and a tool for this is the use of microfluidics, however, related research is still not properly appreciated by the materials development community, representing an area that must still be properly explored, so that synthesis protocols are well established. This work aims to investigate the production of nanostructured particles of metal oxides, especially SiO2, from a microfluidics device, correlating the experimental parameters and characteristics of the device. Initially, the microreactor was obtained using a do-it-yourself (DIY) approach using more accessible materials than the traditional methodology, with the architecture designed in CAD. Subsequently, the influence of the concentration of precursors, from the same stock solutions, and the increase in the flow of reagents inserted into the microfluidics system was investigated. Finally, it was possible to observe particles with an average size between 78 and 118 nm and with low dispersion, much smaller than when obtained by the traditional batch method.