Facing fluid dynamics through a friendly shortcut though of limited validity: the superposition principle

O princípio da superposição é invocado de maneira ampla na física, mas o estudante deve ter em mente que sua validade limita-se às situações regidas por equações lineares. Tal é o caso do eletromagnetismo, em contraste com a dinâmica de fluidos. Nesta ultima, as equações são em geral não-lineares, podendo contudo se reduzir a equações lineares num caso particular de grande interesse, capaz inclusive de abranger situações dependentes do tempo. O objetivo desse artigo de cunho pedagógico é explorar as analogias deste caso com o eletromagnetismo, de forma a possibilitar uma introdução rápida à dinâmica de fluidos por parte do estudante não familiarizado com este ramo fascinante porém geralmente ausente da formação do físico. Nesse processo daremos ênfase ao traçado de linhas de corrente mediante o uso de ferramentas gráficas computacionais que, acreditamos, facilitarão ao estudante a percepção da analogia mencionada.The superposition principle is widely invoked in physics. However, the student should bear in mind that its validity implies that the system under focus is governed by linear equations. Such a condition is usually fulfilled in electromagnetism, but not in fluid dynamics, where the governing equations are generally non-linear ones. Nevertheless, such equations become linear in an important particular case, which applies even to time dependent situations. Our aim in this pedagogical article is to explore the analogies of such a case with electromagnetism. We believe that this approach can make easier to introduce fluid dynamics to a typical student, generally not acquainted at all with the principles of this branch of increasing importance in physics. We emphasize the plot of streamlines by making use of computational graphical tools which hopefully helps to clarify the proposed pedagogical strategy

Análise do centro de custo de um edifício de alto padrão: desafios e proposições

Since a building demands several activities, containing limits and restrictions, planning and control procedures that consider such aspects are necessary. Construction control is a complex job, as it is an activity that presents many variables and belongs to a dynamic and changing environment. With the objective of diagnosing the use of the cost center tool, with regard to the determination of challenges and presentation of proposals for solutions, data were collected from a high standard building, with emphasis on external and internal masonry services and subfloor of the pavements by measuring them in loco, later the calculation of the predicted through the project was carried out. With the available resources, it was possible to compare what was planned, executed and budgeted, in addition, an analysis was made of how the company organizes itself and controls its costs, proposing technical improvements. Finally, it was noted that, despite the benefits arising from cost control, the company does not use this tool, due to the allocation of inputs in the Integrated Business Management System (ERP) not being carried out properly.Visto que uma edificação demanda diversas atividades, contendo limites e restrições, são necessários procedimentos de planejamento e controle que considerem tais aspectos. O controle de obra é um trabalho complexo, pois é uma atividade que apresenta muitas variáveis e pertence a um ambiente dinâmico e mutável. Tendo como objetivo diagnosticar o uso da ferramenta de centro de custo, no que se refere à determinação de desafios e apresentação de proposições de soluções, foram levantados dados de um edifício de alto padrão, com ênfase nos serviços de alvenaria externa e interna e contrapiso dos pavimentos tipo mediante medição in loco dos mesmos, posteriormente realizou-se o cálculo do previsto por meio do projeto. Com os recursos disponíveis, foi possível comparar o que foi planejado, executado e orçado, além disso, foi feita a análise de como a empresa se organiza e controla seus custos, propondo melhorias técnicas. Por fim, notou-se que, apesar dos benefícios advindos do controle de custo, a empresa não faz o uso dessa ferramenta, em virtude da alocação dos insumos no sistema Integrado de Gestão Empresarial (ERP) não ser realizada de forma devida

Electron-beam irradiation preserves nutritional profile of Agaricus bisporus Portobello

All over the world, mushrooms are highly consumed due to their high contents of digestible proteins, carbohydrates, vitamins and fibers. Mushrooms contain about 90% of water, which leads to a faster deterioration due to senescence, browning, water loss and microbial attack. Despite of the immense popularity of this food worldwide, data regarding alternative technologies to increase mushrooms shelf-life are scarce. Ionizing radiation processing is recognized as a safe and effective method for conservation, being widely used to extend the shelf-life of raw foods. The present work reports the effects of storage time (0, 4 and 8 days) and electron-beam irradiation on the nutritional composition (moisture, fat, proteins, ash, carbohydrates and energy) of Agaricus bisporus Portobello samples. The irradiation was performed with a 10 MeV energy irradiator at the doses of 1, 2 and 5 kGy. The proximate composition was evaluated by AOAC official procedures. Storage time (ST) and electron-beam (EB) irradiation showed a significant interaction in all cases (p-value > 0.05), indicating that the effects potentially exerted by ST depended on EB dose and vice-versa. Considering the individual effect of each factor, EB induced more changes than ST, which in fact had a significant effect only for protein and carbohydrates. Among different EB doses, despite the significant differences, it is evident that the nutritional profiles were not greatly changed with any applied dose. Therefore, up to 5 kGy, EB seems to be a suitable conservation treatment for A. bisporus Portobello.Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), C2TN (UID/Multi/04349/2013), grant to A. Fernandes (SFRH/BPD/114753/2016) and L. Barros contract; European Structural and Investment Funds (ESIF) (Regional Operational Program Norte 2020, Project ValorNatural®); Rural Development Program (Project MicoCoating, PDR2020-101-031472); International Atomic Energy Agency (IAEA) Coordinated Research Project D61024 DEXAFI.info:eu-repo/semantics/publishedVersio

Combined effects of irradiation and storage time on the nutritional and chemical parameters of dried Agaricus bisporus Portobello mushroom flour

Abstract: Portobello variety of Agaricus bisporus mushrooms, appreciated for its taste, makes it desirable to be eaten fresh and also as flour in soups and gravies. Gamma and electron-beam radiation at four doses (1, 2, 5, and 10 kGy) were used to analyze its preservation effect on Portobello mushroom flour. A proximate analysis, as well as the impact on fatty acids, tocopherols, soluble sugars, organic acids, and ergosterol profiles, were performed every 3 months, during a storage period of 1 year. Gamma rays preserved mannitol (most abundant soluble sugar) over the 12 months, while electron beam radiation preserved organic acids. No significant changes were sought for any radiation type, and the slight changes extracted from the estimated marginal means reveal a tendency for irradiation as having preserving effects of nutrients and other important molecules. Thus, both irradiation types, up to 10 kGy are suitable for preservation of A. bisporus Portobello flour.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/AGR/00690/2020), C2TN (UID/Multi/04349/2013) for R.V.C. Cardoso’s grant (SFRH/BD/137436/2018), M. Carocho’s research contract. L. Barros and A. Fernandes also thank FCT’s funding through the institutional scientific employment program-contracts. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador ValorNatural R . Acknowledgments are also due European Agricultural Fund for Rural Development (EAFRD), through the Rural Development Program (PDR2020), within the scope of Project MicoCoating (PDR2020-101-031472).info:eu-repo/semantics/publishedVersio

Combined effects of irradiation and storage time on the nutritional and chemical parameters of dried Agaricus bisporus Portobello mushroom flour

Portobello variety of Agaricus bisporus mushrooms, appreciated for its taste, makes it desirable to be eaten fresh and also as flour in soups and gravies. Gamma and electron-beam radiation at four doses (1, 2, 5, and 10 kGy) were used to analyze its preservation effect on Portobello mushroom flour. A proximate analysis, as well as the impact on fatty acids, tocopherols, soluble sugars, organic acids, and ergosterol profiles, were performed every 3 months, during a storage period of 1 year. Gamma rays preserved mannitol (most abundant soluble sugar) over the 12 months, while electron beam radiation preserved organic acids. No significant changes were sought for any radiation type, and the slight changes extracted from the estimated marginal means reveal a tendency for irradiation as having preserving effects of nutrients and other important molecules. Thus, both irradiation types, up to 10 kGy are suitable for preservation of A. bisporus Portobello flour.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/AGR/00690/2020), C2TN (UID/Multi/04349/2013) for R.V.C. Cardoso’s grant (SFRH/BD/137436/2018), M. Carocho’s research contract. L. Barros and A. Fernandes also thank FCT’s funding through the institutional scientific employment program-contracts. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador ValorNatural R . Acknowledgments are also due European Agricultural Fund for Rural Development (EAFRD), through the Rural Development Program (PDR2020), within the scope of Project MicoCoating (PDR2020-101-031472).info:eu-repo/semantics/publishedVersio