Vertical axis wind turbine performance prediction: a new approach to the double multiple streamtube model

The vertical axis wind turbines (VAWT) have been suffering an increased acceptance for urban wind turbines integration in the future smart grid for decentralized generation (DG). The VAWT have several advantages over the more conventional horizontal axis wind turbines (HAWT): the smaller number of components; low sound emissions; their insensitivity to fast changes in wind flow direction; a lower architectural visual impact; the ability to operate closer to the ground; and others. But, the VAWT aerodynamic performance is more complex to simulate and predict due to its three dimensional operation. Several mathematical models have been presented to predict the VAWT performance, such as the double multiple streamtube (DMS) model. With the aim of presenting a tool to ease the study of complex shaped VAWTs, being at the same time able to be easily integrated in computational design tools, a new approach to the DMS model is presented in this paper

Broker colaborativo: gestão de recursos energéticos distribuídos

Neste trabalho é apresentado um Sistema de Informação (SI) cujo objetivo é contribuir para a colaboração entre VE possibilitando a sua entrada no mercado de energia elétrica, permiitindo deste modo que o proprietário do VE seja compensado. Esta compensação incidiria em medidas de minimização do investimento inicial na compra do VE e na criação de um modelo de armazenamento de energia mais sustentável. A este SI chamou-se de Broker Colaborativo ou simplesmente Broker e deverá permitir ao proprietário do VE criar um perfil com a sua informação pessoal, com informação do VE que possui e com informação relativa à colaboração que pretende efetuar, ou seja, locais e percentagem da bateria que pretende usar na colaboração. Para assegurar a entrada no mercado de energia torna-se necessário agrupar e filtrar um número significativo de VE, sendo essa responsabilidade atribuída ao Broker. Sendo a otimização do consumo de energia um fator importante neste trabalho, a implementação do Broker foi efetuada sobre o paradigma de Cloud Computing (será utilizada a designação abreviada de Cloud) onde os recursos energéticos são partilhados. A Clod possuiu uma grande capacidade de escalonamento onde se poderão criar os recursos à medida da necessidade. A utilização da Cloud permite que as especificações iniciais das máquinas virtuais, necessárias para alojar a base de dados ou os ficheiros do Broker, possam ser configuradas conforme o número de utilizadores do sistema. Assim, não se desperdiçam recursos que não seriam utilizados. Devido a estes aspetos dinâmicos, que estão intrínsecos ao fator humano, o Broker foi implementado utilizando um módulo de integração com a rede social Facebook esperando-se desta forma, que a colaboração entre diferentes VE seja difundida através dos amigos e conhecidos de cada utilizador da colaboração. Sendo assim, este trabalho pretende criar um sistema de informação onde os proprietários de VE possam juntar-se e criar uma colaboração possibilitando a sua entrada no mercado da energia elétrica. Essa colaboração será alargada recorrendo a uma rede social e compensada através de créditos. É abordado o tema das plataformas de Cloud como uma plataforma sustentável e vantajosa para o desenvolvimento de sistemas com grande potencial de crescimento

Equity research - Walmart Inc.

Mestrado Bolonha em FinançasWalmart Inc. (WMT) is a leading retailer and wholesaler that sells affordable food and non-food items through its “every day low prices” mantra. Each week, approximately 220 million customers visit the company’s 10,500 stores and clubs under 48 banners in 24 countries and eCommerce websites. In fiscal year 2021, WMT recorded half a trillion dollars in Revenue (the largest Fortune 500 company in the world) and employed over 2.3 million associates. WMT has a BUY recommendation with a 2022YE price target of $164.56/share, implying an upside potential of 20$137.05/sh., although with medium risk. The current undervaluation is mainly explained by the downward trend in operating margins over the last few years. The retail phase of selling uniformly through a “one format fits all” channel, where customers are served purely through brick and mortar stores, are gone. The modern-day customer requires an omnichannel approach where brick and mortar stores are integrated with online platforms to create a superior shopping experience. The dynamic process of selling products online, and its challenging economics, has been the main driver for the operating margin performance of Walmart. The present research studies the impacts of the investments announced by WMT’s Executive team from fiscal year 2022 onwards, and the potential outcomes of its operational performance. In the event that key operational risks materialize throughout the forecast horizon, the outlook for the Price Target changes to $127.2/sh., or a potential downside of 7$193.1/share, or a 41% upside potential.A Walmart Inc. é uma empresa líder no comércio retalhista e grossista de produtos alimentares e não alimentares, tendo como foco estratégico “preços baixos todos os dias”. A cada semana, cerca de 220 milhões de clientes visitam 10,500 lojas de 48 diferentes representações em 24 países e plataformas online. No ano fiscal de 2021, a Walmart registou mais de 500 mil milhões em vendas (sendo maior empresa da Fortune 500 global), e empregou mais de 2.3 milhões de pessoas. A Walmart tem uma recomendação de investimento para “COMPRA”, com um preço alvo de $164.56/ação no final do 2022, implicando uma potencial valorização de 20$137.05/ação no dia 1 de Outubro de 2021, no entanto com risco médio. A atual subvalorização da empresa é maioritariamente explicada pela tendência decrescente das margens operacionais nos últimos anos. A fase do retalho em que se baseava numa venda de produtos através de um único canal, pura e exclusivamente através de lojas físicas, deu-se por terminada. O consumidor moderno requer uma integração das lojas físicas com as plataformas digitais no sentido de criar uma experiência de compra mais conveniente e ajustada às suas necessidades. O processo dinâmico de vender produtos online, e a desafiante tarefa de obter retorno neste canal, tem sido o principal condutor de performance das margens operacionais da Walmart. O presente relatório estuda os impactos dos investimentos anunciados pela direção executiva da Walmart a partir do ano fiscal de 2022, e os potenciais resultados na performance operacional da empresa. Na possibilidade de certos riscos operacionais relevantes se materializarem, o preço alvo muda para $127.2/ação, com uma potencial desvalorização de 7$193.1/ação, ou uma potencial valorização de 41%.info:eu-repo/semantics/publishedVersio

Darrieus vertical axis wind turbines: methodology to study the self-start capabilities considering symmetric and asymmetric airfoils

The rapid growth of wind power generation and the need for a smarter grid with decentralized energy generation has increased the interest in vertical axis wind turbines (VAWT), especially for the urban areas. For the urban areas the VAWT offer several advantages over the horizontal ones, so their acceptance is rising. The lift-type VAWT (Darrieus wind turbines) have a natural inability to self-start without the help of extra components. The existing methodologies are usually used to optimize the wind turbine performance, but not its ability to self-start. Indeed, studying the aerodynamic behavior of blade profiles is a very complex and time-consuming task, since blades move around the rotor axis in a three-dimensional aerodynamic environment. Hence, a new methodology is presented in this paper to study the self-start ability of VAWT, which offers a substantial time reduction in the first steps of new blade profiles development. Both symmetrical and asymmetrical airfoils are targeted in our study, presenting comprehensive results to validate our methodology

Plágio : um problema forense

Nas últimas décadas, o plágio tem sido perspetivado como um problemagrave nas mais diversas esferas sociais e prossionais, da academia até à justiça,com consequências sérias. Importa, por isso, questionar o papel desempenhadopela linguística forense nestes casos. Este artigo começa por contextualizar a problemáticado plágio, em geral, e do plágio académico, em particular. Tomandocomo exemplo o caso do Reino Unido, aborda a relevância das políticas de prevençãoe combate ao plágio e a sua aplicação no Brasil e em Portugal e discuteo papel desempenhado tradicionalmente pela linguística forense na deteção deplágio. Descrevendo os contributos desta área da linguística para os processos deanálise e deteção, questiona a função da linguística forense na análise de casos deplágio, identicando, com bases em casos reais, os marcadores linguísticos maisrobustos na deteção e análise de textos suspeitos. O artigo termina com uma discussãosobre a natureza multidisciplinar da linguística forense, questionando se,em casos de plágio, deverá limitar-se à comparação textual e à justicação dessesresultados, ou se deverá adotar uma abordagem multidisciplinar que permita interpretaros resultados encontrados.Over the last decades, plagiarism has been seen as a serious problem in social and professional settings alike, from the academy to the legal community, with serious consequences. It is thus paramount to discuss the role played by forensic linguistics in these cases. This article begins with a discussion of plagiarism, in general, and academic plagiarism, in particular. It takes the UK as an example to debate the relevance of plagiarism policies and their enforcement in Brazil and in Portugal and the role traditionally played by forensic linguistics in detecting plagiarism. The article lists some of the contributions of this eld of linguistics for plagiarism analysis and detection, and then discusses the role of forensic linguistics in the analysis of plagiarism claims. Some of the linguistic markers that are most relevant when detecting and analysing plagiarism are identi ed, based on real cases. The article concludes with a discussion of the multidisciplinarity of forensic linguistics, to argue that forensic linguistic analysis of instances of plagiarism should go beyond the textual comparison and the explanation of the results thereof to enable a multidisciplinary interpretation of those results

Large Geographical Area Aerial Surveillance Systems Data Network Infrastructure Managed by Artificial Intelligence and Certified Over Blockchain: a Review

This paper proposes an aerial data network infrastructure for large geographical area surveillance systems. The work presents a review of previous works from the authors, existing technologies in the market and other scientific work, with the goal of creating a data network supported by Autonomous Tethered Aerostat Airships used for sensor fixing, drones deployment base and meshed data network nodes installation. The proposed approach for data network infrastructure supports several independent and heterogeneous services from independent, private and public companies. The presented solution employs Edge Artificial Intelligence (AI) systems for autonomous infrastructure management. The Edge AI used in the presented solution enables the AI management solution to work without the need of a permanent connection to cloud services and is constantly feed by the locally generated sensor data. These systems interact with other network AI services to accomplish coordinated tasks. Blockchain technology services are deployed to ensure secure and auditable decisions and operations, validated by the different involved ledgers

Strength in young rhythmic gymnasts

The aim of this study was: 1) verify if the level of strength in young Portuguese gymnasts change according to competition levels and ranking positions; 2) compare the level of strength in finalists’ gymnasts of different competition levels; 3) identify the strength tests that discriminate the gymnasts from the different competition levels. The sample consisted of 68 Portuguese young gymnasts (11.7±0.6 years old) of two different competition levels (Base and 1st division). The International Gymnastics Federation recommended tests for strength assessment were applied. For the statistical analysis, Mann-Whitney and Kruskal-Wallis nonparametric tests, and the discriminant function (forward stepwise) were used. The 1st division presented higher results than the Base gymnasts in all strength tests. Regarding to competition levels by ranking groups, we observed that the finalists in Base level showed higher results than the remaining ranking groups in all strength tests. In 1st division level gymnasts, the finalists achieved higher results only in 66.7% of strength tests than the remaining ranking groups. The finalists in 1st division had higher number of years of training practice in RG and training volume than the finalists in Base level. However, the 1st division gymnasts obtained higher results in 66.7% tests but a superior statistical significance in only one strength test. Lastly, the tests “rope skipping” and “partial trunk elevations” were the strength tests that discriminate the gymnasts groups according to the competitive level

Morphological Characteristics of Portuguese Rhythmic Gymnasts in Different Competition Levels

This study aimed to: (1) compare morphological and training characteristics in Portuguese gymnasts across competitive levels; (2) investigate the morphological variables with higher discriminatory power between groups; (3) determine which morphological variables better explain performance. The sample (n=164) consisted of gymnasts at three competition levels (base, 1st division and elite) from Portugal. 19 anthropometric and 2 body composition measurements were performed. Somatotype was defined by Health-Carter method. Training data were collected by interviewing. For the statistical analyses, Kruskal-Wallis test, linear regression and discriminant function were used. Portuguese gymnasts (13.5±2.0 years) presented 43.7±9.3 kg of body mass, 152.6±8.9cm of height, 18.5±2.4k g/m2 of BMI, 17.5±4.1% of body fat, endomorph-ectomorph somatotype and 16.9±7.5 hours/week of training volume. Elite gymnasts differed from other groups in having lower skinfolds and body fat; and higher training volume and training years. The elite and the 1st division showed higher ectomorphy and lower endomorphy component than the base. Thus, the elite presented morphological and training characteristics closer to the international standards, followed by the 1st division and the base. The variables that best discriminate the gymnasts by competition levels were body fat and lower limb length. Furthermore, body fat was the main morphological predictor of performance in competitio

Biological maturation of Portuguese rhythmic gymnasts in different competition levels of performance

The aims of the present study were: (1) identify and compare the biological maturity in Portuguese gymnasts across competitive levels; (2) investigate how morphological variables and training volume behave in the different status and indicators of maturity and (3) determinate if the maturity status influences the competitive performance. The sample (n=164) consisted of three competition levels (Base, 1st division and Elite) from Portugal. Anthropometric measurements and body composition were performed. For analysis of biological maturation, the sexual and somatic maturation were evaluated. For the statistical analysis, Mann-Whitney and Kruskal-Wallis tests, Pearson correlation and Linear Regression were used. In total, 63.4% of gymnasts had not yet reached menarche and the higher competition level, lower the number of gymnasts with menarche. On mean, all groups had reached the age at peak height velocity. The higher the competition level, higher the chronological age and age at peak height velocity. Thus, the maturation indicators showed a delay in pubertal development in all competition levels and the elite gymnasts seem present a later pubertal development. The chronological age, the values of body mass, height, BMI and body fat increased with the maturity status according all maturity indicators. However, gymnasts with different maturity status revealed similar training volume. Finally, the maturational status explained 11.5% of competition success with higher advantage in the competitive performance to prepubertal gymnasts. Thus, the premenarcheal status and a higher age at peak height velocity contribute to performance in Rhythmic Gymnastics