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​Topological optimization is a numerical analysis technique used in many applications such as additive manufacturing, casting, industry, plastic automotive and others. Educational algorithms have been developed, mostly two-dimensional configuration and with well-defined domains, which clearly describe the various possibilities of boundary conditions found in structures. The aim of this study is to evaluate the domains of topological optimization in some two-dimensional cases and contribute for the training and insertion of students in research activities. For the optimization of the topology, pre-established educational codes were used, such as sigmund’s code, the finite element theory to define the meshes and generate the matrix with displacements and supports, through software such as MATLAB®. From the analysis of these domains, it was possible to verify that some educational algorithms do not work correctly as they should. The results of this study provided knowledge about the first optimization algorithms and the Evolution of their approaches to design the details of the numerical aspects of the code and its equations. Due to the facts mentioned it is concluded that it is important to know in detail the domains used in two-dimensional educational algorithms and to what extent each of the algorithms facilitates work with a specific boundary condition. In addition, the evaluation of two-dimensional algorithms and optimization of the approaches studied helped to consolidate and expand knowledge about technological development and software for analysis and simulations.

O presente trabalho apresenta o projeto de um dispositivo e os testes realizados em um sistema de auxílio na prevenção de contaminações pelo Sars-Cov2 com a desinfecção do ar pela utilização de UVC como ação germicida. O sistema foi testado com E.colis e proporcionou no ar tratado uma visível taxa de inativação das colônias de bactérias aspergidas em sua entrada.

As usual, The Academic Society Journal is always looking for partnerships and initiatives to increase its reach. One of the goals of our journal and of our society as a whole is to enable the scientific community to publish their research without fees. The Open Access format has brought several benefits to the popularization of science since its emergence, bringing quality knowledge to students and institutions that do not have access to paid content. In this issue, we would like to introduce our new editorial member, Prof. Mauro Machado de Oliveira, Chief Editor of REGRASP Journal (seer.spo.ifsp.edu.br/index.php/regrasp). Thus, crowning our partnership, we hope that other initiatives can continue forming links and creating networks that facilitate, as always, the daily lives of those who write, those who review and those who read the papers, not the publishers' profits. Our doors are always open!

Nos últimos anos, as células a combustível de membrana de troca protônica em alta temperatura (HT-PEMFC) foram objetos de diversas pesquisas a fim de remover muitos desafios levantados durante a operação em baixa temperatura. O estado-da-arte em eletrólitos para PEMFC, Nafion®, apresenta mecanismos de condução de prótons altamente dependentes de água, o que limita a operação nesses sistemas em 100ºC. O aumento da temperatura de operação de uma célula PEMFC é desejado devido à contribuição da temperatura na aceleração das reações eletroquímicas. Contudo, o aumento da temperatura exige uma nova proposta para eletrólitos, seja por otimização das propriedades do Nafion ou por desenvolvimento de membranas que não dependam de água para a condução protônica. Neste contexto, as membranas de PBI (polibenzimidazol) dopadas com ácido fosfórico têm sido consideradas uma alternativa bastante promissora para eletrólitos sólidos operantes em alta temperatura, devido à combinação de condução de prótons satisfatória em condições de baixa umidade relativa e excelente estabilidade térmica. No entanto, membranas baseadas em PBI apresentam algumas desvantagens como perda do ácido que pode ocorrer por meio de uma série de mecanismos, incluindo evaporação, difusão, transporte capilar ou lixiviação por água condensada. Mesmo assim, a tecnologia HT-PEMFC é mais interessante, pois, ela trabalha acima da temperatura de ebulição da água, portanto a água gerada está representada apenas na fase de vapor, dessa forma, modelos monofásicos são mais simples de estudar computacionalmente. Dessa forma, foram estudados dois modelos de formato de placas: serpentina com múltiplos canais e interdigital, com área geométrica de eletrodo de 5 cm2 através de simulações computacionais no software COMSOL Multiphysics 5.3a, sendo desenvolvidos e validados com a intenção de auxiliar na interpretação de resultados experimentais. Com isso, o presente trabalho priorizou estudos experimentais e computacionais quanto ao comportamento do ácido fosfórico na membrana, difusão reversa de vapor d\'água e distribuição de temperatura através da membrana, fluxo dos gases, carga de catalizadores, alteração do substrato, tipos de combustíveis e mudanças no posicionamento de entrada e saída dos canais de fluxo dos gases. Em geral as curvas de polarização apresentadas, mostraram uma boa concordância entre os resultados experimentais e computacionais. Foi demonstrado que uma quantidade considerável de vapor d\'água pode atravessar o MEA no sentido do cátodo para o ânodo. Em geral, o aumento da estequiometria favoreceu o aumento do desempenho da célula e foi constatado que a fração molar de ácido fosfórico diminui com o aumento da temperatura e da umidade relativa. In recent years, high temperature proton exchange membrane fuel cells (HT-PEMFC) have been the subject of several researches in order to remove many challenges raised during low temperature operation. The state-of-the-art electrolyte for PEMFC, Nafion®, features highly water-dependent proton conduction mechanisms, which limits operation in these systems to 100ºC. The increase in operating temperature of a PEMFC cell is desired due to the contribution of temperature to the acceleration of electrochemical reactions. However, the increase in temperature requires a new proposal for electrolytes, either by optimizing the properties of Nafion or by developing membranes that do not depend on water for proton conduction. In this context, phosphoric acid-doped PBI (polybenzimidazole) membranes have been considered a very promising alternative for solid electrolytes operating at high temperature, due to the combination of satisfactory proton conduction under conditions of low relative humidity and excellent thermal stability. However, PBI-based membranes have some disadvantages such as acid loss that can occur through a series of mechanisms, including evaporation, diffusion, capillary transport or leaching by condensed water. Even so, the HT-PEMFC technology is more interesting because it works above the boiling temperature of water, so the water generated is represented only in the vapour phase, thus, single-phase models are simpler to study computationally. Thus, two plate format models were studied: serpentine with multiple channels and interdigital, with a geometric electrode area of 5 cm2 through computer simulations in COMSOL Multiphysics 5.3a software, being developed and validated with the intention of helping in the interpretation of experimental results. Thus, the present work prioritized experimental and computational studies on the behavior of phosphoric acid in the membrane, back diffusion of water vapor and temperature distribution in the membrane, gas flow, catalyst charge, change substrate, fuel types, and changes in inlet and outlet placement of gas flow channels. In general, the presented polarization curves showed a good agreement between the experimental and computational results. It has been shown that a considerable amount of water vapour can cross through the MEA from the cathode to the anode. In general, the increase in stoichiometry favored the increase in cell performance and it was found that the molar fraction of phosphoric acid decreases with increasing temperature and relative humidity.