No abstract

Resumo -O artigo descreve a construção de um tanque hidráulico para o cálculo da perda de carga em dutos cilíndricos retos e a execução dos ensaios. O tanque possui estrutura simples, baixo custo, robustez e versatilidade necessárias para a realização de ensaios de fácil execução, baseados no registro dos tempos associados à variação da altura da coluna de água num tubo vertical. A utilização deste equipamento em aulas experimentais mostrou-se muito eficaz, possibilitando a comprovação de resultados teóricos a partir da utilização de modelos reais. Os resultados obtidos são apresentados em planilhas eletrônicas, cuja elaboração baseou-se na aplicação dos princípios de conservação de massa e energia no escoamento de fluidos viscosos, e nas equações de perda de carga distribuída e localizada. O experimento proposto constitui uma ferramenta pedagógica interessante, tendo em vista que sua execução requer a participação ativa dos alunos na realização dos ensaios e na execução de cálculos. A rotina de cálculos, visando comparar valores experimentais perda de carga obtidos experimentalmente com valores teóricos, abrange uma sé-rie de conceitos e equações da Mecânica dos Fluidos, propiciando que a aprendizagem desse conteúdo seja feita a partir de um problema real. Palavras-chave -Perda de carga. Tanque hidráulico. Mecânica dos fluidos. Abstract -The article describes the construction of a hydraulic tank designed for head loss calculation in straight cylindrical pipeline and the essays execution.The tank has low cost, simple structure, robustness and versatility required for carrying out easy execution tests, upon the recording of the time associated with changes in height of the water column in a vertical tube. The use of this equipment in practical lessons was very effective, engaging students in carrying out the tests and performing calculations. The obtained results were satisfactory and presented on spreadsheets, whose development consists on applying the principles of the mass and energy conservation in the flow of viscous fluids, as well as equations for continuous and local head losses. This experimental activity is an interesting pedagogical tool, since its implementation requires the active participation of students in carrying out tests calculations. The routine of calculations, aiming to compare head losses experimentally obtained with theoretical values, covers many concepts and equations of Fluid Mechanics, providing an opportunity for learning this subject upon the analysis of a real problem.

Antimicrobial resistance has been attributed to the overuse of antibiotics.To control the use of antibiotics, Brazil adopted the RDC 20/2011. A comparison the antibiotic-resistance profi le of bacterial has provided important insights into resistance evolution. Enterococci are ubiquitous bacteria recommended to be used as a sentinel organism, in national surveillance systems, for tracking antimicrobial resistance through the food chain. The present study aimed to evaluate the diversity and antimicrobial resistance of enterococci collected from food in South Brazil in 2017 (pos-RDC 20/11) for comparison with isolated in 2007 (pre-RDC 20/11). A total of 310 enterococci were isolated from vegetables and products of animal origin, identifi ed by PCR and MALDI-TOF, tested for antimicrobial susceptibility and screened for resistance genes. Enterococcus casselifl avus was dominant in vegetables and E. faecalis i n products of animal origin. Enterococcal isolates in 2017 were mostly sensitive to ampicillin, gentamicin, chloramphenicol, and vancomycin when compared to isolated collected in 2007. While resistance levels to most compounds remained relatively stable, multidrug resistance decreased by 24% during this period. Our results suggest that RDC 20/11 had a positive outcome in controlling the spread of antimicrobial resistance. This study provides baseline data to measure future changes in the prevalence of resistant enterococci.