Turbulence
Mostrando 1-12 de 366 artigos, teses e dissertações.
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1. Heart rate turbulence assessed through ergometry after myocardial infarction: a feasibility study
ABSTRACT BACKGROUND: Coronary artery disease is an important cause of morbidity and mortality. The impact of ventricular arrhythmias with impaired cardiac vagal activity is one of the most recently studied prognostic factors. However, there are no studies evaluating the phenomenon of heart rate turbulence (HRT) during physical exertion. OBJECTIVE: To stu
Sao Paulo Medical Journal. Publicado em: 2022
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2. MGF Methods for Fixed and Gain Saturated Optically Preamplified FSO Links Impaired by Misalignments and Atmospheric Turbulence
Abstract The Gaussian approximation is commonly used to evaluate the performance of free space optical communication systems. However, other performance evaluation methods such as the saddle point approximation, Chernoff bound and the modified Chernoff bound have also been used. This paper investigates the performance of fixed and gain saturated optically pr
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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3. Numerical and experimental evaluation of the thermally stratified atmospheric boundary layer in wind tunnels
Abstract The atmospheric boundary layer (ABL) flow occurs due to the interaction between the Earth’s surface and atmosphere, and it usually happens under thermal stratification. Therefore, in order to emulate this phenomenon, atmospheric wind tunnels need appropriate devices, such as spires and cubical roughness elements, at the entrance of the wind tunnel
REM, Int. Eng. J.. Publicado em: 2021-01
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4. Silences in media coverage of the World Cup in Pernambuco, Brazil
Abstract The 2014 World Cup occurred in Brazil at a time of great political turbulence and change in communications markets. From the standpoint of a person involved in media coverage of this championship, the MA thesis titled Os silêncios, os silenciamentos e a cobertura midiática da Copa do Mundo em Pernambuco (Silences, silencing and media coverage of t
Sociologias. Publicado em: 2020-04
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5. Compression of the Left Atrium and Pulmonary Veins Due to Ascending and Descending Aortic Aneurysms
Abstract An 89-year-old female patient presented to our cardiology outpatient clinic complaining of shortness of breath and back pain. Chest X-ray demonstrated a widened mediastinum. Transthoracic echocardiography showed an ascending aortic aneurysm and the modified apical 5-chamber view showed that left atrium was compressed between the ascending and descen
Braz. J. Cardiovasc. Surg.. Publicado em: 2020-04
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6. SIMULATION AND EXPERIMENTAL INVESTIGATION OF POWER CONSUMPTION, GAS DISPERSION AND MASS TRANSFER COEFFICIENT IN A MULTI-PHASE STIRRED BIOREACTOR
Abstract Bio-oxidation leaching of refractory gold concentrate was carried out in a typical gas-liquid-solid three-phase stirred bioreactor. The bacteria, which adhered to solid particle surfaces and spread over the liquid phase, require sufficient oxygen and nutrient of carbon and nitrogen, and then the mass transfer rate should be considered. However, the
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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7. 3D numerical investigation of mixture formation and combustion in a DISI engine at part-load under stratified operation
This work investigates through numerical simulation, the operation of a big bore direct fuel injection spark ignition engine, at part load under stratified operation. It evaluates fuel-air mixture preparation and combustion process with the adoption of detailed chemical kinetics mechanisms for both Isooctane and Ethanol, and applying adaptive mesh refinement
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2020
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8. Aerodynamic effects on a high slenderness concrete chimney
Resumo Este trabalho apresenta os resultados da determinação teórico-experimental do comportamento aerodinâmico de uma chaminé esbelta de concreto armado, com 150m de altura e esbeltez 30. Foram construídos dois modelos reduzidos: um rígido para medição das pressões e outro aeroelástico, reproduzindo as principais características dinâmicas da es
Rev. IBRACON Estrut. Mater.. Publicado em: 13/12/2019
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9. AN INVESTIGATION OF THE HEAT TRANSFER PERFORMANCE OF DUAL IMPROVED INTERMIG IMPELLERS IN A STIRRED TANK WITH AN INNER HEATING COIL
Abstract The heat transfer process in a stirred tank of diameter T=0.5m equipped with dual-layer improved Intermig impellers and helical coils was investigated by experiment and numerical simulation methods. The temperature field, the temperature boundary layer lateral to the coil and the heat transfer coefficient were measured at different rotational speeds
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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10. Numerical Simulation of a Pitching Airfoil Under Dynamic Stall of Low Reynolds Number Flow
ABSTRACT: In this research, viscous, unsteady and turbulent fluid flow is simulated numerically around a pitching NACA0012 airfoil in the dynamic stall area. The Navier-Stokes equations are discretized based on the finite volume method and are solved by the PIMPLE algorithm in the open source software, namely OpenFOAM. The SST k - ω model is used as the tur
J. Aerosp. Technol. Manag.. Publicado em: 14/11/2019
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11. Agency Costs and Scarce Resources: Influences on Brazilian Franchising
RESUMO Este artigo revisita uma tradicional questão na literatura em franchising: o mix contratual, ou seja, a proporção entre franquias e lojas próprias. Analisam-se 270 redes brasileiras para entender melhor o cenário nacional. Ressalta-se a dinâmica dessa proporção ao longo do tempo considerando como possíveis explicações o problema dos custos
BBR, Braz. Bus. Rev.. Publicado em: 19/08/2019
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12. Application of an alternative mesh morphing method on the numerical modeling of oscillating wave surge converters
RESUMO Uma das tecnologias capazes de explorar a energia das ondas, baseada na captação das componentes horizontais do movimento destas, aliada a um sistema placa-pistão, vem experimentando um notável desenvolvimento ao longo dos últimos anos, tal dispositivo é conhecido como conversor oscilante por translação de ondas. Este possui um grande potencia
RBRH. Publicado em: 29/07/2019