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

Aplicação de fungicidas via água de irrigação por aspersão convencional para o controle da brusone (Pyricularia oryzae) em arroz.

Plantas de arroz da cultivar IAC-25 foram inoculadas aos 21 dias de idade com 5x10 conidios de Pyricularia oryzae/ml de suspensao. Parcelas de 12 x 12m foram irrigadas por 4 aspersoes setoriais (ZE-305). Os fungicidas foram aplicados atraves do Aplicador Portatil de Produtos Quimicos. Foram 5 as aplicacoes com intervalos de 7 a 10 dias, e inicio 15 dias apos a inoculacao. A lamina media de agua aplicada foi de 3,0mm. A porcentagem de brusone no "pescoco" da panicula e o peso em gramas de graos em 2000 paniculas foram de 8,1 e 11000; 41,4 e 9477, 84,9 e 7052 para os tratamentos trifenil hidroxido de estanho (750 g ia/ha), IBP (960 IA/HA) e testemunha sem fungicida respectivamente. O aumento de producao das parcelas tratadas com trienil hidroxido de estanho foi de 55,9% em relacao a testemunha. Os resultados mostraram a viabilidade da aplicacao de fungicidas via agua de irrigacao por aspersao convencional visando o controle da brusone em arroz

Co-amorphization of olanzapine and saccharin : a pathway to increase solubility in water

Communication presented at the 12th Annual Symposium, Pharmaceutical Solid State Research Cluster (PSSRC). 12-14 September 2018, Leuven, BelgiumN/

Cable robot for non-standard architecture and construction: A dynamic positioning system

In the past few years, cable-driven robots have received some attention by the scientific community and the industry. They have special characteristics that made them very reliable to operate with the level of safeness that is required by different environments, such as, handling of hazardous materials in construction sites. This paper presents a cable-driven robot called SPIDERobot, that was developed for automated construction of architectural projects. This robot has a rotating claw and it is controlled by a set of 4 cables that allow 4 degrees of freedom. In addition to the robot, this paper introduces a Dynamic Control System (DCS) that controls the positioning of the robot and assures that the length of cables is always within a safe value. Results show that traditional force-feasible approaches are more influenced by the pulling forces or the geometric arrangement of all cables and their positioning is significantly less accurate than the DCS. Therefore, the architecture of the SPIDERobot is designed to enable an easily scaling up of the solution to higher dimensions for operating in realistic environments.This work is partly funded by the project PTDC/ATPAQI/ 5124/2012 - Robotic Technologies for Non-Standard Design and Construction in Architecture. This work is also financed by the ERDF European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT Portuguese Foundation for Science and Technology within project ”FCOMP - 01-0124-FEDER-022701”info:eu-repo/semantics/publishedVersio

Megacolon e megaesôfago chagásicos diagnosticados na infância e com provável transmissão vertical

A doença de Chagas congênita é mais comumente identificada nos recém nascidos com sinais sugestivos de infecção intrauterina. Outras expressões clínicas são menos conhecidas e referências de manifestações compatíveis com a fase crônica da doença são raras na faixa etária pediátrica. Apresenta-se o caso de paciente em que, aos sete anos de idade, foram diagnosticados megaesôfago e megacolon secundários a tripanosomíase. A etiologia foi confirmada por meio de xenodiagnóstico, sorologias e achados anátomo-patológicos. Com base na epidemiologia, foi possível descartar outras vias de infecção que não a transmissão vertical. O diagnóstico deve figurar entre crianças com constipação intestinal e/ou sintomas de dismotilidade esofágica, mesmo fora das zonas endêmicas para a tripanosomíase.Reports on children presenting symptoms compatible with the chronic phase of Chagas disease are sporadic. We report a case of a 7-year-old boy who had megaesophagus and megacolon, both of them a consequence of the trypanosomiasis. The etiology was established by means of laboratory and histological features. Based on epidemiological data, the authors concluded that vertical transmission was the most probable route of acquisition. This diagnosis should be considered in children presenting similar complaints, even those living away from endemic areas

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)