Pressure drop calculation in a fuel element of a pool type reactor

Even with the advances of hardware in computer sciences, sometimes it is necessary to simplify the simulation in order to optimize the results given the same calculation runtime. The object of this study is a thermodynamic analysis of the core of a pool type research reactor, focusing on natural circulation. Due to the high geometrical complexity of the core, the scale transfer process becomes an essential step to the thermodynamic study of the reactor. This process takes place by determining the effective equivalent properties obtained from a detailed simulation of the core and transferring them to a porous medium having a coarse mesh while preserving the overall characteristics. In this way, it will be able to obtain the quadratic resistance coefficient KQ by calculating the pressure drop inside the fuel element. To observe in detail the behavior of this flow, longitudinal and transversal cross sections will be made in different points, thereby observing the velocity and pressure distributions. The analysis will provide detailed data on the fluid flow between the fuel plates enabling the observation of possible critical points or undesired behavior. The whole analysis was made by using the commercial code ANSYS CFX ver. 12.1. This is study will provide data, as a first step to enable future simulations which will consider the entire reactor

Aplicação de métodos geofísicos e mecânicos a pavimentos rodoviários

Mestrado em Engenharia CivilO presente trabalho visa estudar os principais métodos geofísicos e mecânicos passíveis de serem utilizados na caracterização de pavimentos rodoviários flexíveis. Nesse contexto, apresenta duas componentes essenciais: uma fortemente ligada à área da Geofísica ; e outra mais ligada aos métodos habituais de caracterização das camadas que constituem os pavimentos rodoviários. Destacam-se como objectivos fundamentais, avaliar a utlidade dos métodos geofísicos na caracterização de pavimentos rodoviários, estudar a aplicabilidade do método MASW para estimar os módulos de deformabilidade das camadas de uma estrutura de pavimento, e correlacionar os respectivos módulos com os obtidos segundo a aplicação de ensaios mecânicos. Em Portugal, ainda não se verifica uma utilização tão frequente dos métodos geofísicos, como acontece em alguns países europeus. Se a metodologia Georadar apresenta alguma difusão, mais não seja a nível académico, o mesmo não pode ser dito acerca dos métodos sísmicos aplicáveis a pavimentos rodoviários. Entre estes, destacam-se os métodos sísmicos de superfície, estudados por alguns investigadores com o intuito de determinar o perfil de velocidades das ondas S de uma estrutura de pavimento, e consequentemente, obter parâmetros elásticos dos materiais. No que diz respeito aos ensaios mecânicos, duma maneira geral o deflectómetro de impacto tem sido o ensaio não destrutivo mais reconhecido na caracterização estrutural de pavimentos. Por sua vez, os ensaios laboratoriais continuam a desempenhar um papel importante no estudo de diferentes parâmetros que influenciam as propriedades dos materiais e dos pavimentos. Os parâmetros mecânicos determinados com a aplicação de métodos sísmicos e mecânicos, devem ser analisados à luz dos estados de tensão-deformação mediante os quais são obtidos. Desta maneira, é normal que os módulos de deformabilidade determinados com a aplicação dos referidos métodos apresentem valores distintos. Partindo dos pressupostos referidos no último parágrafo, no presente trabalho foram aplicadas algumas das metodologias estudadas na parte teórica desta dissertação. Desse modo, foi possível comparar os módulos de deformabilidade obtidos com a aplicação de métodos geofísicos, mecânicos e empírico-mecanicistas, e averiguar a importância dos processos geofísicos na área dos pavimentos rodoviários.The aim of this work is to study the main geophysical and mechanical methods that can be used in the characterization of flexible road pavements. In this context, it presents two major components. One strongly linked to the Geophysics Area, and other more related to the standard methods of categorization of the layers that compose the road pavements. The most relevant purposes of the work are: to evaluate the utility of the geophysical methods in the characterization of road pavements; study the applicability of the MASW method to estimate the modulus of each layer of the pavement; and correlate the respective modulus with the ones obtained following the mechanical essays. Portugal still doesn’t show a very frequent use of the geophysical methods, as it happens in some other European countries. If the Georadar methodology presents some diffusion, at least at academic level, the same can’t be said about seismic methods applied to road pavements. Among them, stands out the superficial seismic methods, which are studied by some researchers in order to determine the VS velocity profile of a pavement system and then establish the elastic parameters of the materials. In what concerns to the mechanical essays, the falling weight deflectometer (FWD) has been shown the most recognized nondestructive essay in the structural characterization of pavements. On the other hand, the laboratorial tests still have an important role in the study of the different parameters that influence the material and pavement properties. The mechanical parameters determined through the application of seismic and mechanical methods, should be analyzed looking to the tension-deformation levels from which they are obtained. Thus, it’s usual that the modulus determined by the application of the referred methods presents differing values. Based on the assumptions in the final paragraph, in the present work were studied some of the methodologies applied in the theoretical part of this dissertation. Thus, it was possible to compare the modulus obtained from the application of geophysical methods, mechanical and mechanistic-empirical, and found the importance of geophysical processes in the road pavements area

Estruturas metálicas temporárias

Mestrado em Engenharia CivilCom o decorrer dos tempos e o avanço da tecnologia é evidente o aumento do número de eventos realizados com recurso à montagem de estruturas temporárias. Desde vários tipos de tendas, palcos e plateias, estrados autorreguláveis, naves industriais, polidesportivos e multiusos, a projetos especiais direcionados para condições mais específicas. Devido à crescente procura por este tipo de mercado, são exigidos elevados critérios de qualidade e segurança das estruturas e superiores níveis de conforto. Este documento insere-se num estágio realizado numa empresa internacional de montagem de estruturas para eventos e centra-se na montagem de uma tenda do evento Rock in Rio 2013 na cidade do Rio de Janeiro. O caso de estudo analisado nesta dissertação foca-se no projeto e verificação de segurança da estrutura da tenda VIP, recorrendo ao software de cálculo estrutural Metal 3D 2013, e em todo o procedimento para montagem e desmontagem da estrutura.Through time and technology advancement, the increasing number of events using the assembly of temporary structures is evident. These range from different types of tents, stages and audiences, to self-regulating platforms, industrial sheds, sports centers and multipurpose halls, and special projects aiming specific conditions. Due to growing demand for this market, high quality, elevated safety standards and higher levels of comfort are required for all structures. This document is part of an internship at an internacional enterprise, that designs, assembles and manages temporary structures at various events. The intership focuses on assembly of a tent for “Rock in Rio 2013” an event taking place in Rio de Janeiro. The case study analyzed in this thesis focuses on the design and safety verification of the VIP tent structure, using the “Metal 3D 2013” structural calculation software and on the entire procedure of assembly and disassembly of that structure

Manipulating the pitch size constrains the players’ positioning during unbalanced soccer small-sided games played by different age groups

We aim to investigate the impact of variable soccer pitch sizes on the position of players during unbalanced small-sided games (SSGs) and compare the responses of players from two different age groups. Forty-eight young players (n = 24 under-13 and n = 24 under-14) took part in the study and played 3 vs. 3 + 1 SSGs on two different pitch sizes (smaller: 36 x 27 m / 139m2 per player; and larger: 40 x 29 m / 166 m2 per player). Players’ positions on the pitch (length, width, length-to-width ratio, stretching index, and spatial exploration index) were assessed by the positional data provided by global position system devices and were compared within age groups and between game formats using a two-way analysis of variance. Results showed higher values of spatial exploration index (SEI) in the larger SSGs than in the smaller format (p<.001). Moreover, a higher length (p<0.001) and length-to-width ratio (p<.001) was observed in the younger group. Finally, the larger format presented higher values of SEI and stretching index, independent of the age group (p<.001). In the smaller format, U-14 players presented a higher stretching index, while in the larger format U-13 players presented higher values in the same variable. We conclude that enlarging the pitch size constrains players’ behaviour during SSGs, and older players are more able to deal with this more complex task context than younger ones

Some statistical methods directed the information centers

Este estudo visa mostrar algumas técnicas estatísticas aplicadas na gestão informacional nas unidades de informação através da utilização de métodos de mensuração e métricas quantitativas atreladas a estudos relacionados à bibliometria, cienciometria, econometria entre outros. Os estudos envolvendo estatística podem ser descritivos, para construção de indicadores, inferencial através de modelos teóricos ou empíricos. As técnicas estatísticas permitem que de base de dados sejam extraídas informações relevantes à tomada de decisão.  Assim, será brevemente explanando sobre probabilidade, distribuição de frequência, séries estatísticas, covariância e correlação, regressão linear e números índices.Este estudio apunta a mostrar algunas técnicas estadísticas aplicadas en la gestión informacional en las unidades de información a través del uso de métodos de medición y métricas cuantitativas relacionadas a los estudios en bibliometria,  cienciometria, econometría entre otros. Los estudios que involucran estadística pueden ser descriptivos, para la construcción de indicadores, o inferenciales mediante modelos teóricos o empíricos. Las técnicas estadísticas permiten que desde las bases de datos se extraiga información relevante para la toma de decisiones. Así se expondrá brevemente sobre la probabilidad, la distribución de frecuencia, las series estadísticas, la covariancia y correlación, la regresión lineal y los números índices.This study aims to show some statistical techniques applied in information management in the units of information through the use of methods of measurement and quantitative metrics tied to studies related to bibliometrics, scientometrics, econometrics among others. The studies involving statistics can be descriptive, for construction of indicators, inferential models through theoretical or empirical. Statistical techniques allow the database to be extracted relevant information for decision making. This will briefly explaining about probability, frequency distribution, statistical series, covariance and correlation, linear regression and index numbers

GESTÃO DE CAPITAL DE GIRO LÍQUIDO E DE FLUXO DE CAIXA EM RISCO DE EMPRESAS DE BENS INDUSTRIAIS LISTADAS NA BMF& BOVESPA

O objetivo deste estudo foi avaliar o desempenho de empresas brasileiras de bens industriais quanto à gestão de capital de giro líquido e quanto à capacidade de geração de caixa em risco, haja vista que estas temáticas estão intrinsecamente associadas e que seu bom gerenciamento é condição necessária para a manutenção da sustentabilidade financeira organizacional. Neste intuito, foi realizado um levantamento com nove empresas listadas na BMF&BOVESPA, dentre uma população de 16 companhias. Foram coletados 47 relatórios contábeis trimestrais por empresa entre 1999 e 2010, onde os dados foram formatados de acordo com as orientações de Fleuriet, Kehdy e Blanc (2003) e do método indireto de fluxo de caixa (GITMAN, 2004). A análise dos dados procedeu-se através de estatística descritiva, teste não-paramétrico Kruskal-Wallis, regressão linear e simulação de Monte Carlo para o cálculo do risco. Quanto à gestão do capital de giro líquido, foi verificado que as empresas possuem dificuldades para financiar e gerenciar seu capital de giro líquido, cujas chances de solvência são de 17%, de inadimplência são 51% e de insolvência são de 32%. Quanto à gestão de caixa, a maioria das empresas têm chances superiores a 50% de terem fluxos de caixa positivos, ainda que o risco da não ocorrência esteja entre 34% e 50 %. Comentários adicionais estão no final do artigo

Paleoproterozoic juvenile magmatism within the northeastern sector of the São Francisco paleocontinent: insights from the shoshonitic high Ba-Sr Montezuma granitoids

New, integrated petrographic, mineral chemistry, whole rock geochemical, zircon and titanite U?Pb geochronology, and zircon Hf isotopic data from the Montezuma granitoids, as well as new geochemical results for its host rocks represented by the Corrego Tingui Complex, provides new insights into the late- to post-collisional evolution of the northeastern S~ao Francisco paleocontinent. U?Pb zircon dates from the Montezuma granitoids spread along the Concordia between ca. 2.2 Ga to 1.8 Ga and comprise distinct groups. Group I have crystallization ages between ca. 2.15 Ga and 2.05 Ga and are interpreted as inherited grains. Group II zircon dates vary from 2.04 Ga to 1.9 Ga and corresponds to the crystallization of the Montezuma granitoids, which were constrained at ca. 2.03 Ga by the titanite U?Pb age. Inverse age zoning is common within the ca. 1.8 Ga Group III zircon ages, being related to fluid isotopic re-setting during the Espinhaco rifiting event. Zircon ?Hf(t) analysis show dominantly positive values for both Group I ( 4 to ?9) and II ( 3 to ?8) zircons and TDM2 model ages of 2.7?2.1 Ga and 2.5?1.95 Ga, respectively. Geochemically, the Montezuma granitoids are weakly peraluminous to metaluminous magnesian granitoids, enriched in LILES and LREE, with high to moderate Mg# and depleted in some of the HFSE. Their lithochemical signature, added to the juvenile signature of both inherited and crystallized zircons, allowed its classification as a shoshonitic high Ba?Sr granitoid related to a late- to post-collisional lithosphere delamination followed by asthenospheric upwelling. In this scenario, the partial melting of the lithospheric mantle interacted with the roots of an accreted juvenile intra-oceanic arc, being these hybrid magma interpreted as the source of the Montezuma granitoids. The Corrego Tingu? Complex host rocks are akin to a syn- to late-collisional volcanic arc granitoids originated from the partial melting of ancient crustal rocks. The results presented in this study have revealed the occurrence of juvenile rocks, probably related to an island arc environment, that are exotic in relation to the Paleo- to Neoarchean crust from the S~ao Francisco paleocontinent?s core

Potassium urinary excretion and dietary intake A cross-sectional analysis in 8-10 year-old children

Background: Data from studies assessing the intake of potassium, and the concomitant sodium-to-potassium ratio are limited. The aim of this study was to evaluate potassium and sodium-to-potassium ratio intake in 8-10 year-old children. Methods: A cross-sectional survey was carried out from January to June 2014 and data from 163 children (81 boys) were included. Potassium intake was estimated by 24-h urine collection and coefficient of creatinine was used to validate completeness of urine collections. Urinary sodium and sodium-to-potassium ratio were also analysed. A 24-h dietary recall was used to provide information on dietary sources of potassium. Height and weight were measured according to international standards. Results: The mean urinary potassium excretion was 1701 +/- 594 mg/day in boys, and 1682 +/- 541 mg/day in girls (p = 0.835); 8.0 % of children met the WHO recommendations for potassium intake. The mean sodium excretion was 2935 +/- 1075 mg/day in boys and 2381 +/- 1045 mg/day in girls (p < 0.001) and urinary sodium-to-potassium ratio was 3.2 +/- 1.4 in boys, and 2.5 +/- 1.1 in girls (p = 0.002). The mean fruit and vegetable intake was 353.1 +/- 232.5 g/day in boys, and 290.8 +/- 213.1 g/day in girls (p = 0.101). Conclusions: This study reported a low compliance of potassium intake recommendations in 8-10 year-old children. Health promotion interventions are needed in order to broaden public awareness of potassium inadequacy and to increase potassium intake