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

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

Cartilage tissue engineering using electrospun PCL nanofiber meshes and MSCs

Mesenchymal stem cells (MSCs) have been recognized for their ability to differentiate into cells of different tissues such as bone, cartilage, or adipose tissue, and therefore are of great interest for potential therapeutic strategies. Adherent, colony-forming, fibroblastic cells were isolated from human bone marrow aspirates, from patients undergoing knee arthroplasties, and the MSCs phenotype characterized by flow cytometry. Afterward, cells were seeded onto electrospun polycaprolactone nanofiber meshes and cultured in a multichamber flow perfusion bioreactor to determine their ability to produce cartilagineous extracellular matrix. Results indicate that the flow perfusion bioreactor increased the chondrogenic differentiation of hBM-MSCs, as confirmed either by morphological and RT-PCR analysis. Cartilage-related genes such as aggrecan, collagen type II, and Sox9 were expressed. ECM deposition was also detected by histological procedures. Collagen type II was present in the samples, as well as collagen type I. Despite no statistically significant values being obtained for gene expression, the other results support the choice of the bioreactor for this type of culture.M. Alves da Silva would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her grant (SFRH/BD/28708/2006). The authors would like to acknowledge the patients of Hospital de S. Marcos, Braga, Portugal, for the donation of the biological samples, as well to its medical staff. The authors would also like to thank the Institute for Health and Life Sciences (ICVS), University of Minho, Braga, Portugal, for allowing the use of their research facilities. Authors would like specially to acknowledge Luis Martins for his valuable help with the histological procedures and Goreti Pinto for the aid in the microscopy. We thank Ana M. Frias for the important help with the FACS procedure. Finally, we would like to acknowledge the European NoE EXPERTISSUES (NMP3-CT-2004-500283). This work was partially supported by the European FP7 Project Find and Bind (NMP4-SL-2009-229292)