Assessing aerodynamic flutter instability in prismatic structures with rectangular cross sections

Neste artigo estuda-se a ocorrência de instabilidade aerodinâmica por 'flutter' em estruturas prismáticas esbeltas de secção retangular. Considera-se um modelo com 2 graus de liberdade e obtém-se a sua formulação adimensional identificando-se um número mínimo de parâmetros adimensionais que regem a ocorrência de instabilidade por 'flutter' . Obtém-se uma muito boa concordância entre os resultados do modelo de 2 graus de liberdade e os resultados existentes na literatura. Este artigo tem 2 objetivos: (i) definir as condições para as quais estruturas esbeltas com secções retangulares podem instabilizar por 'flutter' sob a ação do vento e (ii) fornecer uma coleção alargada de resultados sob a forma de tabelas ou gráficos prontos a usar, cobrindo um largo número de casos, que proporciona aos projetistas de estruturas uma ferramenta que estes podem utilizar, a nível de pré-dimensionamento, para prever as velocidades críticas do vento que provocam a instabilidade por 'flutter' .This paper is dedicated to the study of the occurrence of 'flutter' instability in slender prismatic structures of rectangular cross section. A two degree of freedom model is considered and its non dimensional formulation is derived so that a minimum number of non dimensional parameters governing the occurrence of 'flutter' instability are put in evidence. A very good agreement has been obtained by comparing the results of the two degree of freedom model with the results available in the literature. The goal of this document is twofold: (i) to summarize the conditions for which slender structures with rectangular cross sections may get unstable by 'flutter' under the action of steady wind conditions and (ii) to supply a broad collection of data in the form of ready-to-use tables or graphics covering a wide range of cases, that provide a basis for designers to predict the critical wind velocities at the onset of 'flutter' instability.Peer Reviewe

Socioeconomic and household framework influences in school-aged children's eating habits: Understanding the parental roles

Maternal influences on children's diet have been widely studied, while paternal and household frameworks require further research. This study aimed to evaluate how individual, socioeconomic and household characteristics at birth and 7 years (y) impact children's fruit and vegetable (FV) and energy-dense foods (EDF) intake at 10y, distinguishing maternal and paternal effects. The sample included 2750 children evaluated at 7 and 10y in the Portuguese birth cohort Generation XXI. The children's food intake was assessed through a Food Frequency Questionnaire at both ages, where 4 food groups were defined: FV, ‘Sweet foods’, ‘Salty snacks’, and ‘Soft drinks’. The associations between food intake at 7y, parents' and children's characteristics, and food intake at 10y were evaluated via binary logistic regression models. Offspring of older mothers with higher age and education, who live with siblings and had higher family income were likelier to have 5 servings of FV daily at 10y. Children eating 5 portions/day of FV at 7y had higher odds of keeping this pattern at 10y. Higher maternal age and education, and father's education decreased the odds of having soft drinks daily at 10y. Higher family income was linked with lower odds of weekly salty snacks and daily sweet foods at 10y. In conclusion, parental education, maternal age, living with siblings, and higher family income influenced children's FV and EDF intake at 10y. Mothers' effects appear to impact children's food intake more than fathers'. © 2024 The AuthorsG21 was funded by Programa Operacional de Saúde – Saúde XXI, Quadro Comunitário de Apoio III and Administração Regional de Saúde Norte (Regional Department of Ministry of Health). This study was supported by the Portuguese Foundation for Science and Technology (FCT), under the Epidemiology Research Unit of the Institute of Public Health of the University of Porto (UIDB/04750/2020) and the Laboratory for Integrative and Translational Research in Population Health of the University of Porto (LA/P/0064/2020), and DOI identifiers https://doi.org/10.54499/UIDB/04750/2020 and https://doi.org/10.54499/LA/P/0064/2020. MPC benefited from an FCT individual doctoral grant (2020.08314.BD) [https://doi.org/10.54499/2020.08314.BD] and SV is supported by national funds through FCT, under the programme of ‘Stimulus of Scientific Employment –Individual Support’ within the contract 10.54499/2021.01096.CEECIND/CP1686/CT0001 [https://doi.org/10.54499/2021.01096.CEECIND/CP1686/CT0001]

Optimization of filament antennas using the Gauss-Newton method

The project of the Yagi-Uda antenna was optimized using the Gauss-Newton method. The optimization consisted of specifying value interval for directivity, front-to-back ratio and beamwidth and, starting from a pre-defined initial model, the best values for the length and spacing of the elements were determined. For the direct modeling, the method of moments on the integral Pocklington equation was used, which consisted of obtaining the values of directivity, front-to-back ratio and beamwidth from the length and spacing between known elements. The procedure was applied to the synthesis of Yagi-Uda antennas with five and six elements and the results were found to be as good as those obtained in the literature using other optimization methods

The new SWOT for a sustainable world

In today’s complex and changing business environment the concern with sustainability has gained more notoriety. However, companies still do not have a sustainable perspective, but a short-term one, where their values are constantly forgotten and this concept is no longer welcomed. This research demonstrates the need for companies to adapt and to start acting in this direction. Following a set of interviews conducted with professionals with management positions of high responsibility, findings reveal that although sustainability is on the management mind, strategies and tools need to be adapted to be at the core of the organization’s strategic formulation. To support this process, a new SWOT analysis to fit a forward-looking sustainable world is proposed. Furthermore, due to the aggregative nature of the model, it represents an essential tool for an open innovation. “SWOT i” integrates the concern with sustainability as one of its pillars, placing the values and impacts that each decision can have at the center of the strategic formulation, allowing their performance to leverage.info:eu-repo/semantics/publishedVersio

Violence and alcoholism in the family: how are the children affected?

Alcohol Alcohol. 1998 Jan-Feb;33(1):42-6. Violence and alcoholism in the family: how are the children affected? Malpique C, Barrias P, Morais L, Salgado M, Pinto Da Costa I, Rodriques M. SourceChild and Adolescent Psychiatry Department, Hospital Central de Criancas Maria Pia, Porto, Portugal. Abstract We made an evaluation of how children and adolescents are affected if they live in a family environment where violence associated with alcoholism is a feature. Interviews with 20 families and the use of psychological tests on their children were performed in this study. The study has demonstrated the existence of psychopathological disturbances in those families' children, whose immaturity and insecurity were expressed by aggressive behaviour or by depressive manifestations. It also became evident that there was a transgenerational alcoholism-violence frequency

A comparison of the Normal and Laplace distributions in the models of fuzzy probability distribution for portfolio selection

The propose of this work is applied the fuzzy Laplace distribution on a possibilistic mean-variance model presented by Li et al which appliehe fuzzy normal distribution. The theorem necessary to introduce the Laplace distribution in the model was demonstrated. It was made an analysis of the behavior of the fuzzy normal and fuzzy Laplace distributions on the portfolio selection with VaR constraint and risk-free investment considering real data. The results showns that were not difference in assets selection and in return rate, however, There was a change in the risk rate, which was higher in the Laplace distribution than in the normal distribution

Milk quality and financial management at different scales of production on dairy farms located in the south of Minas Gerais State, Brazil.

The objective of this study was to analyze the relationship between aspects related to financial management and The objective of this study was to analyze the relationship between aspects related to financial management and scale of production with quality traits (total bacteria count - TBC; somatic cell count - SCC) and composition (protein, fat, lactose, total solids, and non-fat solids) of refrigerated bulk tank milk from 100 dairy farmers located in the south of Minas Gerais state, Brazil, by application of a semi-structured questionnaire. Dairy farmers were categorized according to the daily milk production: small (lower than 150 L); medium (151 to 500 L); and large (higher than 501 L). Chi-square tests and identification of possible relative risks between financial aspects and current regulation standards (Normative Instruction No. 62 of December 29, 2011, Ministry of Agriculture, Livestock and Supply) associated to TBC (higher 300,000 CFU/mL) and SCC (higher than 500,000 cells/mL) means from bulk tank milk among different milk scales productions were performed. Bulk tanks milk composition met the legislation standards and had not differ between scales of production; however, SCC means within all scales, and TBC of small farmers had not attended the legislation standards and differences were identified (P < 0.05). Regarding the financial management aspects, most farmers had no control over incomes, costs, nor calculated milk production cost, with decreased incidences as scale of production increased. Chi-square tests identified that producers that had no concern about milk quality payment bonuses had TBC means 2.95 times more likely (P < 0.05) to be above the current regulations. Small dairy farmers had a greater negligence of the costs management and hygienic milk production as compared to medium and large farmers. scale of production with quality traits (total bacteria count - TBC; somatic cell count - SCC) and composition (protein, fat, lactose, total solids, and non-fat solids) of refrigerated bulk tank milk from 100 dairy farmers located in the south of Minas Gerais state, Brazil, by application of a semi-structured questionnaire. Dairy farmers were categorized according to the daily milk production: small (lower than 150 L); medium (151 to 500 L); and large (higher than 501 L). Chi-square tests and identification of possible relative risks between financial aspects and current regulation standards (Normative Instruction No. 62 of December 29, 2011, Ministry of Agriculture, Livestock and Supply) associated to TBC (higher 300,000 CFU/mL) and SCC (higher than 500,000 cells/mL) means from bulk tank milk among different milk scales productions were performed. Bulk tanks milk composition met the legislation standards and had not differ between scales of production; however, SCC means within all scales, and TBC of small farmers had not attended the legislation standards and differences were identified (P < 0.05). Regarding the financial management aspects, most farmers had no control over incomes, costs, nor calculated milk production cost, with decreased incidences as scale of production increased. Chi-square tests identified that producers that had no concern about milk quality payment bonuses had TBC means 2.95 times more likely (P < 0.05) to be above the current regulations. Small dairy farmers had a greater negligence of the costs management and hygienic milk production as compared to medium and large farmers

Investigating the photophysical properties and biological efficacy of BODIPY derivatives as photosensitizers in photodynamic therapy

The selectivity of photosensitizers for light activation is a key advantage in photodynamic therapy (PDT), allowing for precise targeting while sparing healthy cells. BODIPY derivatives have emerged as promising PDT candidates due to their tunable photophysical properties and versatile synthesis. Herein, we explore the photophysical characterization and the in vitro photodynamic activity of BODIPY analogues meso-substituted with an anthracene moiety and functionalized with iodine atoms or formyl group at 2,6-position. The formylated anthracene-BODIPY derivative exhibited the highest tumor suppression under irradiation, making it a potential candidate as PDT photosensitizer