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Nesta pesquisa, objetivou-se a analisar os principais obstáculos relacionados ao ensino e a aprendizagem da matemática no ensino fundamental, anos finais. Para a elaboração da referida pesquisa, foram necessárias uma investigação com análise qualitativa e quantitativa dos resultados da prova do SAEPE realizada em 2021. Foi feito uma vasta leitura em sites, documentos e informações atualizadas dos anos 2020/2021 disponibilizados pela Secretaria Municipal de Educação de Goiana-PE. Artigos, dissertações e teses vinculadas ao estudo da Matemática, serviram como embasamento teórico, e subsídio necessários para alcançar nossos objetivos. Obteve-se como resultados, uma visão geral dos principais problemas relacionados às dificuldades do ensino e da aprendizagem da matemática em período pandêmico. Duas turmas do 9º ano foram testadas em escolas distintas da rede pública municipal de Goiana-PE. Ficou evidenciado que a falta de hábitos de estudos regulares e aulas remotas durante todo ano de 2021, provocaram e contribuíram de forma significativa para o desinteresse dos alunos. Dentre os obstáculos e dificuldades, destaca-se em especial, a falta de interpretação das questões matemáticas. Pois, dos 13 alunos testados, apenas cinco sabiam ler e escrever com fluência. Os demais, liam e escreviam pequenas frases corretas. Provavelmente, por não saberem ler, os alunos envolvidos, apresentaram grandes dificuldades de interiorização de conteúdos e conceitos básicos que deveriam ter sido vivenciados em séries anteriores. Portanto, como possível proposta para solução ou superação desses obstáculos à longo prazo, é essencial que o professor de matemática reformule sua metodológica para a próxima etapa e retorno das aulas presenciais.

This paper aims to study the hybrid process of osmotic dehydration and convective air drying of foods. Emphasis has been put on cassava cubes (Manihot esculenta Crantz.). Convective drying kinetics of fresh and osmotically dehydrated cassava cubes was evaluated at the following hot air-drying conditions: temperature 50°C, velocity 1.35 m/s, and absolute humidity 0.060 dry water/g. Experimental results of the moisture loss, solids gain, and incorporation of sodium chloride are shown and analyzed. For estimation of the effective mass diffusion coefficient, experiment data of average moisture content of cassava cubes (fresh and osmotically dehydrated) was fitted to the simplified Fick model and a good agreement was obtained. The effective mass diffusivity of the osmotically dehydrated cassava cube was 2.75 x10-10 m2/s and to fresh cassava cubes 5.45x10-10 m2/s.

Identificamos alguns erros no preenchimento dos dados no EDUCACENSO, por isso foi desenvolvido uma formação ministrada pela equipe de normatização da secretaria aos 34 gestores, 19 adjuntos e 48 digitadores da rede de ensino. Na formação discutiu os possíveis erros, expondo de forma clara e objetiva o desenvolvimento dos cálculos para obtenção dos recursos oferecidos pelo Governo Federal dirimindo as inconsistências no momento de inserção dos dados no sistema em cada unidade de ensino do município de Igarassu.

Resin transfer molding (RTM) is one technique that has been used to produce polymer composites, which consists in injecting a thermoset pre-catalysed resin into a closed mold containing a dry fiber preform. In this sense, this study aims to investigate the effect of the calcium carbonate content (CaCO3) in the polyester resin during the RTM process. Several experiments were conducted using glass fiber mat molded in a RTM system with cavity dimensions 320 x 150 x 3.6 mm, at room temperature, and different injection pressure (0.75 bar) and CaCO3content (0, 10, 20, 30 and 40%). Results of the physical parameters such as viscosity, permeability, and mobility, and flow front position of the resin into the mold along the RTM process are presented and analyzed. From the results was concluded that the higher the injection pressure and lower CaCO3content into the resin, the lower filling time.

This chapter aims to present a theoretical study of the fluid flow in porous media, with particular reference to manufacturing of polymer composites reinforced with fibers via resin transfer molding process. The mass and momentum conservation equations, including the effect of resin sorption by the fibers, and Darcy's law, are presented, and the analytical solution of the governing equation is obtained via method of separation of variables. Predicted results of the flow front, velocity, volumetric flow rate and pressure fields of the resin inside the model, during the injection process, are presented, and the effects of the injection pressure, resin viscosity and sorption term, are also analyzed.

O ensino da matemática na educação fundamental é um desafio para docentes e pesquisadores. Para superar essas barreiras técnicas metodológicas o lúdico tem sido utilizado. O lúdico está associado a dança, a música e ao jogar, consiste em um mecanismo poderoso para aumentar o interesse dos alunos por alguma disciplina ou conteúdo. Essa metodologia torna o aprendizado mais divertido e interessante, possibilitando o ensino do conteúdo de uma maneira leve. Devido a sua importância, este trabalho tem como objetivo utilizar o lúdico como ferramenta no auxílio do ensino de frações. A pesquisa foi realizada em uma Escola Municipal, com 30 alunos da turma do 6º ano, sendo 13 do sexo masculino e 17 do sexo feminino. Foi feito uma análise da temática, através de um questionário, a aplicação do jogo e uma avaliação no final das atividades. Verificou-se que, com a inserção dos jogos nas aulas, elas se tornaram mais dinâmica e prazerosa, promovendo uma maior interação entre os alunos/material-manipulável/professor, que contribuiu para uma melhora na aprendizagem do conteúdo de frações.

In the manufacturing process of ceramic brick, the step of drying needs the control of process variables to uniformly dry the porous material, producing a good end-product. The majority of numerical simulations involving drying of ceramic materials is performed considering only the solid domain, resulting in a very simplified and limited study. This way, the objective of this work is the analysis of the drying process with hot air of an industrial hollow clay brick inside the oven at different temperatures by using computational fluid dynamic (CFD). The results of the temperature and water mass distribution inside the brick and of air in the oven at different times of the drying process are shown, analyzed and checked with experimental data, and it was obtained in a concordance with the data. An equation to calculate the brick water mass diffusivity depending on the drying air temperature was proposed.

This work aims to investigate the infiltration of a CaCO3filled resin using experiments and the PAM-RTM software. A preform of glass fiber mat, with dimensions 320 x 150 x 3.6 mm, has been used for experiments conducted at room temperature, with injection pressure of 0.25bar. The resin contained 10 and 40% CaCO3content with particle size 38μm. The numerical results were evaluated by direct comparison with experimental data. The flat flow-front profile of the rectilinear flow was reached approximately halfway the length of the mold. It was observed, that the speed of the filling decreases with increasing CaCO3content and,the higher the amount of CaCO3in the resin, the lower the permeability of the reinforcement that is found. The reduction in permeability is due to the presence of calcium carbonate particles between the fibers, hindering the resin flow in the fibrous media. The computational fluid flow analysis with the PAM-RTM proved to be an accurate tool study for the processing of composite materials.

Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing techniques of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. Nowadays, RTM is used by many industrial sectors such as automotive, aerospace, civil and sporting equipment. Therefore, the objective of this study is to verify the effect of calcium carbonate mixed in resin in the RTM process. Several rectilinear infiltration experiments were conducted using glass fiber mat molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, room temperature, maximum injection pressure 0.202 bar and different content of CaCO3 (10 and 40%) with particle size of 75μm. The results show that the use of filled resin with CaCO3 influences the preform impregnation during the RTM molding, changing the filling time and flow from position, however it is possible to make the composite with a good quality and low cost.

Resin Transfer Molding (RTM) is one of the composite manufacturing technique that consists in injecting a resin pre-catalysed thermosetting in a closed mold containing a dry fiber preform, where the resin is impregnated. In this sense, the aim of this research is to study theoretically and experimentally the RTM process. Experimental and simulations of the rectilinear infiltration of polyester resin (filled and non filled with CaCO 3 ) in mold with glass fiber preform were performed in cavity with dimensions 320 · 150 · 3.6 mm. Numerical results of the filling time and fluid front position over time were assessed by comparison with experimental data and good accuracy was obtained. It was verified that, the CaCO 3 content affect resin velocity during filling, the permeability of the reinforcement and resin viscosity, thus the filling time is affected strongly.

O camarão marinho Litopenaeus vannamei pode ser cultivado em águas com ampla faixa de salinidade (0,5-60 g L-1). Desta forma, objetivou-se comparar dados de produção desse crustáceo quando cultivado em águas oligohalina (0,5-5,0 g L-1) ou salgada (25,0-40,0 g L-1), utilizando-se modelos matemáticos. Para relacionar as variáveis de manejo com as de produção, os modelos foram formulados com base em um banco de dados com 278 cultivos comerciais da região Nordeste do Brasil. Para estimar os parâmetros dos modelos, utilizou-se a técnica dos mínimos quadrados. A seleção das variáveis foi realizada com o processo de Stepwise associado à transformação de Box e Cox. A adequação das equações e os pressupostos de normalidade, para os erros, foram analisados com base na análise de variância, na estatística de Durbin-Watson, na análise de resíduo e no teste de normalidade. Em todas as equações formuladas, a variável cultivo em água salgada (CAS) foi selecionada, evidenciando diferença significativa (p < 0,05) entre esses sistemas de cultivo.The marine shrimp Litopenaeus vannamei may be reared in a wide range of salinity (0.5-60.0 g L-1). In this study, the production data of shrimp reared either in oligohaline (0.5-5.0 g L-1) or salty waters (25.0-40.0 g L-1) were compared using mathematical models. The models considered variables related to management and production, and were formulated using a database with 278 culture cycles from different shrimp farms in Northeastern Brazil. The least-squares technique was applied to estimate the model’s parameters. The selection of variables used the Stepwise process associated to Box and Cox’s transformation. The adequacy of the equations and the normality estimated for the errors were analyzed on the basis of the analysis of variance in the Durbin-Watson statistics, on the residue analysis and the normality test. For all the formulated equations, the variable ‘culture in salty water’ was selected, evidencing significant differences between these culture systems.

In the processing of high performance composite materials, the RTM process has been widely used by many sectors of the industry. This process consists in injecting a polymeric resin through a fibrous reinforcement arranged within a mold. In this sense, this study aims to simulate the rectilinear infiltration of pure resin and filled resin (40% CaCO3) in a mold with glass fiber preform, using the PAM-RTM commercial software. Numerical results of the filling time and fluid front flow position over time were assessed by comparison with the experimental data and a good accuracy was obtained.

The marine shrimp Litopenaeus vannamei may be reared in a wide range of salinity (0.5-60.0 g L -1 ). In this study, the production data of shrimp reared either in oligohaline (0.5-5.0 g L -1 ) or salty waters (25.0-40.0 g L -1 ) were compared using mathematical models. The models considered variables related to management and production, and were formulated using a database with 278 culture cycles from different shrimp farms in Northeastern Brazil. The least-squares technique was applied to estimate the model’s parameters. The selection of variables used the Stepwise process associated to Box and Cox’s transformation. The adequacy of the equations and the normality estimated for the errors were analyzed on the basis of the analysis of variance in the Durbin-Watson statistics, on the residue analysis and the normality test. For all the formulated equations, the variable ‘culture in salty water’ was selected, evidencing significant differences between these culture systems.