978 resultados para LIQUID FLOW
Resumo:
A hanseníase é um problema de saúde pública no Brasil. As ações de controle estão baseadas no diagnóstico e tratamento dos indivíduos doentes e na vigilância de seus contatos. Os testes sorológicos permitem identificar, entre os contatos, aqueles com maior risco de desenvolver hanseníase. O ML Flow foi utilizado em 2.840 contatos intradomiciliares de casos novos de hanseníase, diagnosticados entre outubro de 2002 e março de 2004, em Minas Gerais. O ML Flow foi positivo em 20,5% dos contatos de hanseníase, sendo maior nos contatos do sexo masculino (22,4%), nos maiores de 15 anos (21,7%), nos contatos de doentes multibacilares (23,9%). A chance de um contato ser soropositivo foi maior se convivia com caso multibacilar (OR=1,75), idade superior a 15 anos (OR=1,38) e sexo masculino (OR=1,25). O acompanhamento desses contatos permitirá, no futuro, avaliar o risco que a soropositividade representa no desenvolvimento de hanseníase.
Resumo:
Estudo transversal em menores de 18 anos, sendo 115 casos novos de hanseníase e 1.011 contatos intradomiciliares. Determinaram-se as proporções da soropositividade do ML Flow e fatores associados ao teste positivo. Observou-se soropositividade em 21,7% dos pacientes e 19,7% dos contatos. Nos pacientes, a regressão logística indicou associação com baciloscopia positiva e número de lesões cutâneas maior que cinco. A análise por árvore de decisão mostrou associação com baciloscopia, classificação de Madri, número de nervos acometidos e idade. Nos contatos, as duas análises indicaram as mesmas associações: classificação do caso-índice, idade e tipo de serviço de saúde. As variáveis que explicaram melhor a soropositividade, em menores de 18 anos, são aquelas associadas à maior carga bacilar. Assim, o teste ML Flow poderia ser utilizado também na infância para ajudar na correta classificação dos pacientes para tratamento e na identificação dos contatos com maior risco de desenvolver hanseníase.
Resumo:
A detecção da hanseníase no município de Paracatu é elevada em menores de quinze anos, abrangendo cerca de 6,8/10.000 hab. em 2003 e é classificada como hiperendêmica. O estudo objetiva analisar a aplicação do teste sorológico do PGL-1 (ML Flow) em 56 de 68 pacientes escolares da rede pública, diagnosticados com hanseníase através da busca ativa de casos no município de Paracatu - MG (2004 a 2006), sendo 71%, paucibacilares. Cerca de 85,2% dos pacientes residiam na área urbana, 55,8% eram do sexo feminino e a doença predominava no grupo de 10 a 14 anos (IC95%:0,49-0,89%) e χ²=7,376, sendo que 15 (26,7%) com resultado do ML Flow positivo. Cinco pacientes tinham incapacidades do Grau 1, da forma clínica Dimorfa (40% ML Flow positivo). O percentual de casos de hanseníase entre os contatos intradomiciliares foi de 46,4%, sendo que 44,9% deles com resultado do teste do ML Flow positivo. O estudo sugere incorporar o teste ML Flow nos serviços de saúde, uma vez que o mesmo auxilia na classificação operacional da doença, controle de contatos intradomiciliares com resultado do teste positivo, visando à detecção precoce dos casos suspeitos de hanseníase.
Resumo:
Nanotechnology plays a central role in ‘tailoring’ materials’ properties and thus improving its performances for a wide range of applications. Coupling nature nano-objects with nanotechnology results in materials with enhanced functionalities. The main objective of this master thesis was the synthesis of nanocrystalline cellulose (NCCs) and its further incorporation in a cellulosic matrix, in order to produce a stimuli-responsive material to moisture. The induced behaviour (bending/unbending) of the samples was deeply investigated, in order to determine relationships between structure/properties. Using microcrystalline cellulose as a starting material, acid hydrolysis was performed and the NCC was obtained. Anisotropic aqueous solutions of HPC and NCC were prepared and films with thicknesses ranging from 22μm to 61μm were achieved, by using a shear casting technique. Microscopic and spectroscopic techniques as well as mechanical and rheological essays were used to characterize the transparent and flexible films produced. Upon the application of a stimulus (moisture), the bending/unbending response times were measured. The use of NCC allowed obtaining films with response times in the order of 6 seconds for the bending and 5 seconds for the unbending, improving the results previously reported. These promising results open new horizons for building up improved soft steam engines.
Resumo:
In the field of energy, natural gas is an essential bridge to a clean, low carbon, renewable energy era. However, natural gas processing and transportation regulation require the removal of contaminant compounds such as carbon dioxide (CO2). Regarding clean air, the increasing atmospheric concentrations of greenhouse gases, specifically CO2, is of particular concern. Therefore, new costeffective, high performance technologies for carbon capture have been researched and the design of materials with the ability to efficiently separate CO2 from other gases is of vital importance.(...)
Resumo:
A thermal Energy Storage Unit (ESU) could be used to attenuate inherent temperature fluctuations of a cold finger, either from a cryocooler working or due to sudden income heat bursts. An ESU directly coupled to the cold source acts as a thermal buffer temporarily increasing its cooling capacity and providing a better thermal stability of the cold finger (“Power Booster mode”). The energy storage units presented here use an enthalpy reservoir based on the high latent heat of the liquid-vapour transition of neon in the temperature range 38 - 44 K to store up to 900 J, and that uses a 6 liters expansion volume at RT in order to work as a closed system. Experimental results in the power booster mode will be described: in this case, the liquid neon cell was directly coupled to the cold finger of the working cryocooler, its volume (12 cm3) allowing it to store 450 J at around 40 K. 10 W heat bursts were applied, leading to liquid evaporation, with quite reduced temperature changes. The liquid neon reservoir can also work as a temporary cold source to be used after stopping the cryocooler, allowing for a vibration-free environment. In this case the enthalpy reservoir implemented (24 cm3) was linked to the cryocooler cold finger through a gas gap heat switch for thermal coupling/decoupling of the cold finger. We will show that, by controlling the enthalpy reservoir’s pressure, 900 J can be stored at a constant temperature of 40 K as in a triple-point ESU.
Resumo:
Cryocoolers have been progressively replacing the use of the stored cryogens in cryogenic chains used for detector cooling, thanks to their higher and higher reliability. However, the mechanical vibrations, the electromagnetic interferences and the temperature fluctuations inherent to their functioning could reduce the sensor’s sensitivity. In order to minimize this problem, compact thermal energy storage units (ESU) are studied, devices able to store thermal energy without significant temperature increase. These devices can be used as a temporary cold source making it possible to turn the cryocooler OFF providing a proper environment for the sensor. A heat switch is responsible for the thermal decoupling of the ESU from the cryocooler’s temperature that increases when turned OFF. In this work, several prototypes working around 40 K were designed, built and characterized. They consist in a low temperature cell that contains the liquid neon connected to an expansion volume at room temperature for gas storage during the liquid evaporation phase. To turn this system insensitive to the gravity direction, the liquid is retained in the low temperature cell by capillary effect in a porous material. Thanks to pressure regulation of the liquid neon bath, 900 J were stored at 40K. The higher latent heat of the liquid and the inexistence of triple point transitions at 40 K turn the pressure control during the evaporation a versatile and compact alternative to an ESU working at the triple point transitions. A quite compact second prototype ESU directly connected to the cryocooler cold finger was tested as a temperature stabilizer. This device was able to stabilize the cryocooler temperature ((≈ 40K ±1 K) despite sudden heat bursts corresponding to twice the cooling power of the cryocooler. This thesis describes the construction of these devices as well as the tests performed. It is also shown that the thermal model developed to predict the thermal behaviour of these devices, implemented as a software,describes quite well the experimental results. Solutions to improve these devices are also proposed.
Resumo:
Cryocoolers have been progressively replacing the use of the stored cryogens in cryogenic chains used for detector cooling, thanks to their higher and higher reliability. However, the mechanical vibrations, the electromagnetic interferences and the temperature fluctuations inherent to their functioning could reduce the sensor’s sensitivity. In order to minimize this problem, compact thermal energy storage units (ESU) are studied, devices able to store thermal energy without significant temperature increase. These devices can be used as a temporary cold source making it possible to turn the cryocooler OFF providing a proper environment for the sensor. A heat switch is responsible for the thermal decoupling of the ESU from the cryocooler’s temperature that increases when turned OFF. In this work, several prototypes working around 40 K were designed, built and characterized. They consist in a low temperature cell that contains the liquid neon connected to an expansion volume at room temperature for gas storage during the liquid evaporation phase. To turn this system insensitive to the gravity direction, the liquid is retained in the low temperature cell by capillary effect in a porous material. Thanks to pressure regulation of the liquid neon bath, 900 J were stored at 40K. The higher latent heat of the liquid and the inexistence of triple point transitions at 40 K turn the pressure control during the evaporation a versatile and compact alternative to an ESU working at the triple point transitions. A quite compact second prototype ESU directly connected to the cryocooler cold finger was tested as a temperature stabilizer. This device was able to stabilize the cryocooler temperature ((≈ 40K ±1 K) despite sudden heat bursts corresponding to twice the cooling power of the cryocooler. This thesis describes the construction of these devices as well as the tests performed. It is also shown that the thermal model developed to predict the thermal behaviour of these devices,implemented as a software, describes quite well the experimental results. Solutions to improve these devices are also proposed.
Resumo:
Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/64337/2009 ; projects PTDC/ECM/70652/2006, PTDC/ECM/117660/2010 and RECI/ECM-HID/0371/2012
Resumo:
The assessment of wind energy resource for the development of deep offshore wind plants requires the use of every possible source of data and, in many cases, includes data gathered at meteorological stations installed at islands, islets or even oil platforms—all structures that interfere with, and change, the flow characteristics. This work aims to contribute to the evaluation of such changes in the flow by developing a correction methodology and applying it to the case of Berlenga island, Portugal. The study is performed using computational fluid dynamic simulations (CFD) validated by wind tunnel tests. In order to simulate the incoming offshore flow with CFD models a wind profile, unknown a priori, was established using observations from two coastal wind stations and a power law wind profile was fitted to the existing data (a=0.165). The results show that the resulting horizontal wind speed at 80 m above sea level is 16% lower than the wind speed at 80 m above the island for the dominant wind direction sector.
Resumo:
INTRODUCTION: Snake bite, a problem in public health, generally occurs where there is no electric power. METHODS: A comparative clinical study was conducted with 102 victims of Bothrops snake bite, from the state of Amazonas, Brazil; 58 victims were treated with liofilizated trivalent antivenom serum (SATL) and 44 victims treated with liquid bivalent and monovalent antivenom serum (SAMBL). RESULTS: 17% (10/58) of patients presented adverse effects with the SATL and 25% (11/44) with the SAMBL. CONCLUSIONS: There was no statistic difference in number of adverse effects between the two types of snake bite antivenom.
Resumo:
This thesis evaluates a start-up company (Jogos Almirante Lda) whose single asset is a board game named Almirante. It aims to conclude whether it makes sense to create a company or just earn copyrights. The thesis analyzes the board game’s market, as part of the general toy’s market, from which some data exists: European countries as well as the USA. In this work it is analyzed the several ways to finance a start-up company and then present an overview of the valuation of the Jogos Almirante based on three different methods: Discounted Cash Flow, Venture Capital Method and Real Options.
Resumo:
A Work Project, presented as part of the requirements for the Award of a Master’s Double Degree in Finance from Maastricht University and NOVA – School of Business and Economics
Resumo:
Research literature and regulators are unconditional in pointing the disclosure of operating cash flow through direct method a section of unique information. Besides the intuitive facet, it is also consistent in forecasting future operating cash flows and a cohesive piece to financial statement puzzle. Bearing this in mind, I produce an analysis on the usefulness and predictive ability on the disclosure of gross cash receipts and payments over the disclosure of reconciliation between net income and accruals for two markets with special features, Portugal and Spain. Results validate the usefulness of direct method format in predicting future operating cash flow. Key
Resumo:
We use a new dataset to study how mutual fund flows depend on past performance across 28 countries. We show that there are marked differences in the flow-performance relationship across countries, suggesting that US findings concerning its shape do not apply universally. We find that mutual fund investors sell losers more and buy winners less in more developed countries. This is because investors in more developed countries are more sophisticated and face lower costs of participating in the mutual fund industry. Higher country-level convexity is positively associated with higher levels of risk taking by fund managers.