2,272 research outputs found
Elementos para o desenho de estruturas de armazenagem e movimentação de GPL : uma abordagem sob o ponto de vista ATEX
Com a progressiva integração de serviços de voz, vídeo e dados, em novos sistemas de
comunicação, resultantes da convergência tecnológica das tradicionais redes locais de
computador e das redes públicas de telecomunicações, tem sido possível satisfazer os
requisitos específicos das aplicações telemáticas, recorrendo a capacidades e protocolos de
transmissão e de comutação adequados aos diferentes níveis de qualidade de serviço,
suportadas nas diferentes interfaces da rede.
Nesta comunicação, caracterizam-se capacidades e limitações de diferentes tecnologias de
acesso de banda larga, suportadas pelas infra-estruturas fixas existentes (xDSL, DOCSIS e
BPL) e pelas redes de acesso via rádio (DECT, FWA, WLAN, WiMAX, HIPERLAN, GSM e
UMTS), em função dos requisitos de qualidade de serviço das aplicações, de acordo com as
especificações das recomendações internacionais existentes. Aborda-se igualmente a
possibilidade de localização de terminais móveis, recorrendo a serviços de suporte da Rede de
Acesso Rádio, bem como o desenvolvimento de aplicações sensíveis ao contexto de utilização
Bowen–Franks groups of reducible bimodal subshifts of finite type
AbstractWe study the Bowen–Franks groups of subshifts of finite type associated with reducible bimodal periodic kneading sequences pairs
Models for project management in 2016 Olympic Games
The Olympic Games are the major sports event on the planet gathering people for all over the world and integrating several kind of resources that need to be managed in order to achieve efficiency and the sustainability of the event. The research question of this paper is “Which project management business model best fit a mega event like the 2016 Olympic Games?” The organizations which participate in the Olympic Games project management in Rio are under the pressure of external scenarios of uncertainty and also intense competition and internally the organizations that manage all the Olympic resources need to deal with limitations of costs and time – the business model adopted can help to achieve a major success of the event. According to studies made on the past Olympics Project Managers face various challenges and the models adopted can made an integration of various and disperse project management tools. The main finding of this research is that project management maturity models benefits management approaches and reinforce the definition and the use of strategic plans enhancing the control techniques of project management and also the sustainability model is necessary to orchestrate the successful completion of a project with the amplitude of Olympic Games.info:eu-repo/semantics/publishedVersio
Modelling of thermoelectric generator with heat pipe assist for range extender application
Recent trends towards electrification of vehicles favour the adoption of waste energy recovery into electricity. Battery-only Electric Vehicles (BEV) need a very large energy storage system so the use of a Range Extender (RE) may allow a significant downsizing of these bulky components. The Internal Combustion Engines (ICE) have two major discarded energy fluxes, engine cooling and exhaust gas. In Extended Range Electric Vehicles (EREV) and hybrids the potential for heat conversion into electricity is particularly convenient. The direct conversion of thermal energy into electricity, using Thermoelectric Generators (TEG) is very attractive in terms of complexity. However, current commercial TEG modules based on Seebeck effect are temperature limited, so they are unable to be in direct contact with the exhaust gases. A way to downgrade the temperature levels without reducing its potential is to interpose Heat Pipes (HP) between the exhaust gas and the modules. This control of maximum temperature at the modules is achieved by regulating the pressure of phase change of the HP fluid. Such design is convenient for engines with large thermal load variations, such as the RE being developed by the team, with a low (15kW) and a high (40kW) power mode of operation. This system will be able to operate efficiently in both modes. The present work presents the thermal modelling of such a system in order to assess the suitability of this approach. This work is complemented with the experimental work being carried out by the team in this subject, already with some published results. The model was validated with experimental data with a good correlation. Therefore, it was possible to demonstrate the potential of this system for wasted heat recovery.MIT Portugal, Fundação para a Ciência e a Tecnologia (FCT
Temperature controlled exhaust heat thermoelectric generation
The amount of energy wasted through the exhaust of an Internal Combustion Engine (ICE) vehicle is roughly the same as the mechanical power output of the engine. The high temperature of these gases (up to 1000°C) makes them
intrinsically apt for energy recovery. The gains in efficiency
for the vehicle could be relevant, even if a small percentage of this waste energy could be regenerated into electric power and used to charge the battery pack of a Hybrid or Extended Range Electric Vehicle, or prevent the actuation of a conventional vehicle's alternator.SFRH / BPD / 51048 / 2010MIT-Pt/EDAM-SMS/0030/200
Alterações na densidade do solo em um sistema agrossilvipastoril na Amazônia Central.
Este estudo teve como objetivo medir as mudanças dos atributos físicos de um Latossolo Amarelo muito argiloso decorrentes da adoção de um sistema agrossilvipastoril
Stock and carbon levels in the soil in the tree lines or pasture lane in integrated production system (iCLF) in the western Brazilian Amazon.
The objective of this study was to evaluate the stock (STC) and the C content (Ccont) in the soil in the tree lines or pasture lane of an integrated system iCLF with Mahogany (Swietenia macrophylla) and Brachiaria brizantha cv. Xaraés sown after corn cultivation in western Brazilian Amazon
A tale of two ends: Repurposing metallic compounds from anti‐tumour agents to effective antibacterial activity
Postgraduate Research (1252) Studentship UIDB/04378/2020The rise in antibiotic resistance coupled with the gap in the discovery of active molecules has driven the need for more effective antimicrobials while focusing the attention into the repurpose of already existing drugs. Here, we evaluated the potential antibacterial activity of one cobalt and two zinc metallic compounds previously reported as having anticancer properties. Compounds were tested against a range of Gram‐positive and ‐negative bacteria. The determination of the minimum inhibitory and bactericidal concentrations (MIC/MBC) of the drugs were used to assess their potential antibacterial activity and their effect on bacterial growth. Motility assays were conducted by exposing the bacteria to sub‐MIC of each of the compounds. The effect of sub‐MIC of the compounds on the membrane permeability was measured by ethidium bromide (EtBr) accumulation assay. Cell viability assays were performed in human cells. Compound TS262 was the most active against the range of bacteria tested. No effect was observed on the motility or accumulation of EtBr for any of the bacteria tested. Cell viability assays demonstrated that the compounds showed a decrease in cell viability at the MIC. These results are promising, and further studies on these compounds can lead to the development of new effective antimicrobials.publishersversionpublishe
Vorton Formation
In this paper we present the first analytic model for vorton formation. We
start by deriving the microscopic string equations of motion in Witten's
superconducting model, and show that in the relevant chiral limit these
coincide with the ones obtained from the supersonic elastic models of Carter
and Peter. We then numerically study a number of solutions of these equations
of motion and thereby suggest criteria for deciding whether a given
superconducting loop configuration can form a vorton. Finally, using a recently
developed model for the evolution of currents in superconducting strings we
conjecture, by comparison with these criteria, that string networks formed at
the GUT phase transition should produce no vortons. On the other hand, a
network formed at the electroweak scale can produce vortons accounting for up
to 6% of the critical density. Some consequences of our results are discussed.Comment: 41 pages; color figures 3-6 not included, but available from authors.
To appear in Phys. Rev.
Intrahepatic Colangiocarcinoma
Introdução: o colangiocarcinoma intra-hepático (CCIhp) é um tumor maligno raro, normalmente diagnosticado num estadio avançado.
São objectivos deste estudo avaliar os resultados da terapêutica do CCIhp e os factores prognósticos com significado estatístico na sobrevida de doentes com esta entidade nosológica tratados no nosso Serviço. Material e métodos: Vinte e um doentes submetidos
a tratamento por CCIhp nos últimos anos, dos quais onze foram operados com intuitos curativos: quatro hepatectomias esquerdas, duas hepatectomias esquerdas alargadas aos segmentos V e VIII, duas hepatectomias direitas, duas bissegmentectomias e uma trissegmentectomia.
Resultados: a mortalidade per-operatória foi de 0% e a pós-operatória (três meses) de 6%. As sobrevidas cumulativas aos 5 anos foram de 14% no total da população, 26% nos doentes submetidos a cirurgia com intuitos curativos e 26% para a sobrevida cumulativa livre de doença. Observou-se recidiva tumoral hepática em cinco doentes, a qual ocorreu aos 1,09 ± 0,82 anos (limites:
0,24-2,08). Os factores que influenciaram a sobrevida da globalidade dos doentes foram o tratamento cirúrgico com intuitos curativos (p=0,028), a presença de invasão vascular (p=0,002) e o valor da fosfatase alcalina no momento do diagnóstico (p=0,044). Entre os doentes operados com intuitos curativos, a presença de invasão vascular influenciou a sobrevida global (p=0,025) e a sobrevida livre
de doença (p=0,002). Conclusões: A ressecção cirúrgica com intuitos curativos aumentou, de forma estatisticamente significativa, a sobrevida dos doentes com CCIhp. No entanto, sendo o diagnóstico geralmente tardio, apenas uma pequena percentagem destes doentes pode beneficiar deste tratamento.info:eu-repo/semantics/publishedVersio
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