Numerical modelling code based on the finite volume method in unstructured grids

In this work, the implementation employed in the new modeling code is described. It is based on the FVM with on a SIMPLE type scheme suitable for unstructured meshes.Fundação para a Ciência e a Tecnologia (FCT

Development of numerical tools to aid the design of complex geometry profile extrusion dies

The research team of this work is involved since the mid-nineties on the development of computational tools to aid the design of profile extrusion dies. Initially, the numerical code employed was based on structured meshes that limited its application to simple geometries. The work planned in this PhD programme comprises the development of a numerical modelling code able to deal with unstructured meshes and its application on the design of profile extrusion dies comprising complex cross sections. In its current state the numerical code under development is able to model de flow of generalized Newtonian fluids inside flow channels using unstructured meshes. This paper describes briefly the current state of the developed code and illustrates its application in a case study involving the design of a profile extrusion die comprising a complex cross section

Design of complex profile extrusion dies through numerical modeling

The achievement of a balanced flow is one of the major tasks encompassed in the design of profile extrusion dies [1]. For this purpose numerical modeling codes may be a very useful aid. The research team involved in this work has been working during the last decade on the development of numerical tools to aid the conception of extrusion dies [1,2]. The design code developed so far carries out the automatic search of a final geometry via an optimization routine coupled with geometry and mesh generators and a 3D computational fluid dynamics (CFD) code based on the finite volume method (FVM). This CFD code is able to model the flow of polymer melts in confined channels, but is inadequate to deal with complex geometries, since it is limited to structured meshes. This work describes the recent efforts made to enlarge the scope of the design procedures, that are currently focused on the development of a modeling code able to deal with unstructured meshes. This code solves the continuity and linear momentum conservation equations, with generalized Newtonian fluids, using a SIMPLE based approach. This paper describes the developed numerical modelling code and its employment in a case study that involves the design of a medical catheter extrusion die, focused on the search of a balanced flow distribution. The results obtained show that the developed numerical code is able to deal with complex geometrical problems, being thus a valuable tool to aid the design of extrusion dies to produce complex profiles.The authors gratefully acknowledge funding from Fundacao para a Ciencia e Tecnologia through the PhD Grant SFRH/BD43632/2008 and FCT (COMPETE Program) under the Projects FCOMP-01-0124 - FEDER-010190 (Ref. PTDC/EME - MFE/102729/2008) and FCOMP-01-0124-FEDER-015126 (Refa. FCT PTDC/EME-MFE/113988/2009), and FEDER, via FCT, under the PEst-C/CTM/LA0025/2011 (Strategic Project - LA 25 - 2011-2012)

Ab-initio study of the relation between electric polarization and electric field gradients in ferroelectrics

The hyperfine interaction between the quadrupole moment of atomic nuclei and the electric field gradient (EFG) provides information on the electronic charge distribution close to a given atomic site. In ferroelectric materials, the loss of inversion symmetry of the electronic charge distribution is necessary for the appearance of the electric polarization. We present first-principles density functional theory calculations of ferroelectrics such as BaTiO3, KNbO3, PbTiO3 and other oxides with perovskite structures, by focusing on both EFG tensors and polarization. We analyze the EFG tensor properties such as orientation and correlation between components and their link with electric polarization. This work supports previous studies of ferroelectric materials where a relation between EFG tensors and polarization was observed, which may be exploited to study ferroelectric order when standard techniques to measure polarization are not easily applied.Comment: 9 pages, 6 figures, 5 tables, corrected typos, as published in Phys. Rev.

Sport practice and plantar pressure in children aged 10–18 years: evaluation using Namrol® Podoprint®

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

Comportamento de variedades de mirtileiro sob cultivo agroecológico.

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Características agronômicas de quatro híbridos de sorgo com capim-sudão avaliados em quatro idades de corte.

Objetivou-se avaliar as características agronômicas dos híbridos de sorgo com capim-sudão BR800, CMSXS 765bmr, CMSXS 766 e 156x2785, destinados à produção de forragem, em quatro idades de corte (52, 61, 67 e 74 dias). O plantio foi realizado em quatro canteiros por híbrido em cada idade de corte, com delineamento de blocos ao acaso. Foram determinadas altura das plantas, número de plantas ha -1 (stand), produção de matéria verde (PMV) e produção de matéria seca (PMS). A altura das plantas variou de 1,53 a 2,55 m, e o híbrido 156x2785 se destacou por apresentar maior altura em relação aos demais híbridos na quarta idade de corte (P<0,05). A correlação da altura com a PMS foi positiva (r = 0,73, P<0,0001). O stand variou de 251,42 a 449,98 mil plantas ha -1, e o híbrido 156x2785 apresentou valores menores que os demais na primeira e segunda época de corte (P<0,05). A PMV variou de 28,86 a 48,00 t ha-1e apresentou-se com variações (P<0,05) entre os híbridos e idades de corte. A PMV apresentou correlação positiva com a PMS (r = 0,52, P<0,0001). A PMS variou de 2,35 a 7,56 t ha-1, sendo que o híbrido CMSXS 766 se destacou por apresentar maior PMS na primeira, segunda e terceira época de corte. Na quarta época de corte a maior PMS foi obtida pelo híbrido 156x2785. O híbrido portador do gene bmr-6, CMSXS 765bmr, apresentou menor PMS que seu par isogênico não portador, CMSXS 766, em todas as idades de corte

Características agronômicas de quatro híbridos de sorgo destinados à produção de forragem, avaliados em quatro idades de corte.

O experimento foi conduzido na Embrapa Milho e Sorgo em Sete Lagoas, MG e objetivou avaliar as características agronômicas dos híbridos de sorgo BRS655, BRS610, BR601 e BR700 destinados à produção de forragem em quatro idades de corte (77, 84, 88 e 95 dias). O plantio foi realizado em quatro canteiros por híbrido em cada idade de corte, com delineamento de blocos ao acaso. Foram determinadas altura das plantas, número de plantas por hectare (stand), produção de matéria verde (PMV) e produção de matéria seca (PMS). A altura das plantas apresentou pouca variação entre os híbridos e a sua correlação com a PMS foi positiva (r = 0,26, P<0,05). O stand também não apresentou diferenças significativas entre os híbridos e apresentou tendência de diminuir com aumento da idade de corte. A PMV variou de 23,71 a 44,14 t ha-1 e apresentou-se com variações (P<0,05) entre os híbridos e idades de corte. A PMS variou de 5,80 a 8,75 t ha-1, sendo que os híbridos que apresentaram maior PMS na primeira, segunda, terceira e quarta épocas de corte foram, respectivamente, BR700, BR601, BR700 e BRS655. Todos os híbridos avaliados apresentaram produtividade elevada para a época em que foram produzidos, podendo ser indicados para produção de silagem para a alimentação de ruminantes

What makes re-finding information difficult? A study of email re-finding

Re-nding information that has been seen or accessed before is a task which can be relatively straight-forward, but often it can be extremely challenging, time-consuming and frustrating. Little is known, however, about what makes one re-finding task harder or easier than another. We performed a user study to learn about the contextual factors that influence users' perception of task diculty in the context of re-finding email messages. 21 participants were issued re-nding tasks to perform on their own personal collections. The participants' responses to questions about the tasks combined with demographic data and collection statistics for the experimental population provide a rich basis to investigate the variables that can influence the perception of diculty. A logistic regression model was developed to examine the relationships be- tween variables and determine whether any factors were associated with perceived task diculty. The model reveals strong relationships between diculty and the time lapsed since a message was read, remembering when the sought-after email was sent, remembering other recipients of the email, the experience of the user and the user's ling strategy. We discuss what these findings mean for the design of re-nding interfaces and future re-finding research