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Analysis of the blood flow behavior through microchannels by a confocal micro-PIV/PTV system

Lima, R.
Fonte: Tohoku University Publicador: Tohoku University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
36.24087%
Over the years, various experimental methods have been applied in an effort to understand the blood flow behavior in microcirculation. Most of our current knowledge in microcirculation is based on macroscopic flow phenomena such as Fahraeus effect and Fahraeus-Linqvist effect. The development of optical experimental techniques has contributed to obtain explanations on the way the blood flows through microvessels. Although the past results have been encouraging, detailed studies on the flow properties of blood in the microcirculation has been limited by several technical factors such as poor spatial resolution and difficulty to obtain quantitative detailed measurements at such small scales. Therefore, there is still a lack of knowledge on the microscale flow behavior of blood cells through microvessels. In recent years, due to advances in computers, optics, and digital image processing techniques, it has become possible to combine a particle image velocimetry (PIV) system with a conventional microscope. As a result, this combination, known as a micro-PIV, has greatly increased the resolution of the conventional PIV. Although the conventional micro-PIV technique has proven to be useful in measuring the flow behavior in microfluidics devices...

New prediction methods for CO2 evaporation inside tubes: Part I - A two-phase flow pattern map and a flow pattern based phenomenological model for two-phase flow frictional pressure drops

CHENG, Lixin; RIBATSKI, Gherhardt; QUIBEN, Jesus Moreno; THOME, John R.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.257961%
An updated flow pattern map was developed for CO2 on the basis of the previous Cheng-Ribatski-Wojtan-Thome CO2 flow pattern map [1,2] to extend the flow pattern map to a wider range of conditions. A new annular flow to dryout transition (A-D) and a new dryout to mist flow transition (D-M) were proposed here. In addition, a bubbly flow region which generally occurs at high mass velocities and low vapor qualities was added to the updated flow pattern map. The updated flow pattern map is applicable to a much wider range of conditions: tube diameters from 0.6 to 10 mm, mass velocities from 50 to 1500 kg/m(2) s, heat fluxes from 1.8 to 46 kW/m(2) and saturation temperatures from -28 to +25 degrees C (reduced pressures from 0.21 to 0.87). The updated flow pattern map was compared to independent experimental data of flow patterns for CO2 in the literature and it predicts the flow patterns well. Then, a database of CO2 two-phase flow pressure drop results from the literature was set up and the database was compared to the leading empirical pressure drop models: the correlations by Chisholm [3], Friedel [4], Gronnerud [5] and Muller-Steinhagen and Heck [6], a modified Chisholm correlation by Yoon et al. [7] and the flow pattern based model of Moreno Quiben and Thome [8-10]. None of these models was able to predict the CO2 pressure drop data well. Therefore...

New prediction methods for CO2 evaporation inside tubes: Part II - An updated general flow boiling heat transfer model based on flow patterns

CHENG, Lixin; RIBATSKI, Gherhardt; THOME, John R.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.248672%
Corresponding to the updated flow pattern map presented in Part I of this study, an updated general flow pattern based flow boiling heat transfer model was developed for CO2 using the Cheng-Ribatski-Wojtan-Thome [L. Cheng, G. Ribatski, L. Wojtan, J.R. Thome, New flow boiling heat transfer model and flow pattern map for carbon dioxide evaporating inside horizontal tubes, Int. J. Heat Mass Transfer 49 (2006) 4082-4094; L. Cheng, G. Ribatski, L. Wojtan, J.R. Thome, Erratum to: ""New flow boiling heat transfer model and flow pattern map for carbon dioxide evaporating inside tubes"" [Heat Mass Transfer 49 (21-22) (2006) 4082-4094], Int. J. Heat Mass Transfer 50 (2007) 391] flow boiling heat transfer model as the starting basis. The flow boiling heat transfer correlation in the dryout region was updated. In addition, a new mist flow heat transfer correlation for CO2 was developed based on the CO2 data and a heat transfer method for bubbly flow was proposed for completeness sake. The updated general flow boiling heat transfer model for CO2 covers all flow regimes and is applicable to a wider range of conditions for horizontal tubes: tube diameters from 0.6 to 10 mm, mass velocities from 50 to 1500 kg/m(2) s, heat fluxes from 1.8 to 46 kW/m(2) and saturation temperatures from -28 to 25 degrees C (reduced pressures from 0.21 to 0.87). The updated general flow boiling heat transfer model was compared to a new experimental database which contains 1124 data points (790 more than that in the previous model [Cheng et al....

Orifice plate meter field performance: formulation and validation in multiphase flow conditions

Campos, Sthener Rodrigues Vieira; Baliño, Jorge Luis; Slobodcicov, Ivan; Florencio Filho, Durval; Paz, Elson Francisco da
Fonte: Philadelphia Publicador: Philadelphia
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.248672%
The performance of orifice plates in real-time monitoring of oil, gas and water standard flow rates was investigated. To this end, a multi-rate test was implemented in two production wells routed individually to a test separator in field operational conditions. The well flow rate was varied in steps by changing the choke opening. The ranges of fluid properties and flow conditions achieved during the experiment were: wellhead pressure from 9073 kPa to 13,278 kPa, wellhead temperature from 47.8 C to 53.5 C, downstream choke pressure from 6770 kPa to 7913 kPa, downstream choke temperature from 41.6 C to 49.1 C, gas–oilratio from 1144 Sm3=Sm3 to 2068 Sm3=Sm3, water-cut from 4.64% to 58.35%, standard oil specific gravity from 0.7988 to 0.8058, standard gas specific gravity from 0.7340 to 0.7550, standard oil flow rate from 46:86 Sm3=d to 266:65 Sm3=d, standard gas flow rate from 62:68 103 Sm3=d to 296:65 103 Sm3=d, standard water flow rate from 18:06 m3=d to 159:33 m3=d. The wells tested showed a different dynamic behavior: while well #2 did not vary significantly the stream composition with flow rate, well #1 produced under gas coning, a near well-reservoir phenomenon that governs the contribution of the reservoir gas-cap to the total stream composition. The multi-rate tests generated two data sets with 1424 flow conditions through two flange-tap orifice plates installed upstream (wellhead) and downstream of a cage choke valve. The ranges of orifice variables were: orifice diameter from 0.03479 m to 0.0430 m...

A relevância do lucro líquido versus fluxo de caixa operacional para o mercado de ações brasileiro; The relevance of earnings versus operating cash flow to the Brazilian stock market

Malacrida, Mara Jane Contrera
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/02/2009 Português
Relevância na Pesquisa
36.24087%
Este trabalho avalia a relevância do fluxo de caixa operacional corrente, accruals e lucros correntes para predizerem o fluxo de caixa operacional futuro e estimarem o retorno das ações das companhias abertas brasileiras. A análise é realizada seguindo o modelo desenvolvido por Barth et al (2001), o qual se baseia no modelo de Dechow et al (1998) e no estudo realizado por Bartov et al (2001). A partir dos modelos teóricos são desenvolvidas 7 hipóteses para analisar a relevância das informações contábeis para o mercado de capitais brasileiro. A pesquisa empírica é desenvolvida a partir das Demonstrações de Fluxo de Caixa publicadas, voluntariamente e pelo método indireto, por companhias abertas com ações listadas na Bolsa de Valores de São Paulo (BOVESPA), no período de 2000 a 2007. As análises são realizadas utilizando dados em painel. As evidências empíricas indicam que o lucro corrente é mais relevante do que o próprio fluxo de caixa operacional corrente para predizer o fluxo de caixa operacional futuro (t+1); os accruals são relevantes para predizer o fluxo de caixa operacional futuro e adicionam capacidade preditiva ao lucro corrente, pois lucro corrente desagregado em fluxo de caixa operacional e seis componentes de accruals mostra-se ainda mais relevante do que o lucro corrente para estimar o fluxo de caixa operacional futuro (t+1). Contudo...

Flow: o que é isso? um estudo psicológico sobre experiências ótimas de fluxo na consciência, sob a perspectiva da psicologia positiva; Flow: What is it? A psychological study on optimal experience of flow in consciousness, from the perspective of Positive Psychology

Kamei, Helder Hiroki
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/08/2010 Português
Relevância na Pesquisa
36.257961%
O presente trabalho visa compreender o que são as experiências de flow, investigando e verificando a qualidade da experiência subjetiva durante a prática de uma determinada atividade intrinsecamente motivadora (a dança-de-salão). Flow é um conceito desenvolvido por Mihaly Csikszentmihalyi, co-fundador do movimento conhecido como Psicologia Positiva, que foi idealizado em 1998 por Martin Seligman. Um dos principais campos temáticos das pesquisas em Psicologia Positiva consiste nos estudos sobre felicidade, sendo que este trabalho pretende contribuir para as pesquisas sobre felicidade e bem-estar subjetivo no Brasil. Para apreender as qualidades da experiência de flow, optou-se pelo método qualitativo e preferiu-se partir da narrativa dos próprios sujeitos, empregando a técnica da entrevista-narrativa norteada por roteiro semi-estruturado. As entrevistas foram realizadas em 6 escolas de dança-de-salão na cidade de São Paulo, sendo selecionados vinte participantes do gênero masculino e feminino, entre 20 e 40 anos de idade, dentre eles 10 alunos que praticavam a dança-de-salão como atividade de lazer e 10 profissionais, professores de dança. Para analisar os depoimentos, foi utilizado o método de derivação empírica das categorias (Csikszentmihalyi & Robinson...

Tocar/jogar Rocksmith : as experiências de flow de jovens guitarristas que jogam games de música

Pfützenreuter, Allan César
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
36.244963%
A presente pesquisa teve como objetivo investigar as experiências de flow de jovens guitarristas ao jogarem o game Rocksmith. Os objetivos específicos foram identificar as condições e as características das experiências de flow presentes no relato de jovens guitarristas ao jogarem Rocksmith e relacionar as condições e características das experiências de flow de jovens guitarristas ao jogarem Rocksmith com as atividades musicais propostas no game. O referencial teórico desta pesquisa está fundamentado na Teoria do Flow de Mihaly Csikszentmihalyi (1992) que investigou as circunstâncias e ambientes que levam um indivíduo a experimentar um estado de imersão e satisfação na realização de determinada atividade, assim como, sistematizou as características daquilo que as pessoas sentem quando vivenciam esta experiência. As experiências de flow têm estreita relação com a motivação intrínseca, a aprendizagem e o desenvolvimento de habilidades cada vez mais complexas. O método desta pesquisa consistiu em um estudo de entrevistas qualitativas com seis jogadores do game Rocksmith que residem em Porto Alegre e Nova Petrópolis, ambas as cidades no Rio Grande do Sul. Como instrumento de coleta de dados, foram utilizadas entrevistas semiestruturadas construídas a partir das sete dimensões da Teoria do Flow. As características reveladas pelos entrevistados ao jogarem Rocksmith mostraram que o game satisfaz as condições e as características das experiências de flow...

Unsteady flow of Oldroyd-B fluids in an uniform rectilinear pipe using 1D models

Carapau, Fernando; Sequeira, Adélia
Fonte: Carapau, F., and Sequeira, A.,"Unsteady flow of Oldroyd-B fluids in an uniform rectilinear pipe using 1D models", Proceedings of the 2006 IASME/WSEAS International Conference on Continuum Mechanics, Chalkida, Greece, May 11-13, 2006, pp. 61-66. Publicador: Carapau, F., and Sequeira, A.,"Unsteady flow of Oldroyd-B fluids in an uniform rectilinear pipe using 1D models", Proceedings of the 2006 IASME/WSEAS International Conference on Continuum Mechanics, Chalkida, Greece, May 11-13, 2006, pp. 61-66.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.102993%
Using the one-dimensional approach based on the director theory which reduces the exact threedimensional equations to a system depending only on time and on a single spatial variable, we analyze the axisymmetric unsteady flow of an incompressible viscoelastic fluid of Oldroyd type in an uniform rectilinear pipe with circular cross-section. From this system we obtain the relationship between average pressure gradient and volume flow rate over a finite section of the pipe and the corresponding equation for the wall shear stress. Attention is focused on the steady flow case with rigid and impermeable walls.

Fluid Flow and Particles Transport in 3-D Packed Beds

Serrenho, A.; Miguel, A. F.
Fonte: Fluid Flow and Particles Transport in 3-D Packed Beds. Publicador: Fluid Flow and Particles Transport in 3-D Packed Beds.
Tipo: Aula
Português
Relevância na Pesquisa
46.06741%
A 3-D numerical study is performed to investigate the effects of periodicity (geometry) on fluid flow and particles transport through fixed beds of spheres. The following packing geometries are studied: cubic- orthorhombic simple, hexagonal, orthorhombic, rhombic-hexagonal, rhombic-pyramidal and tetragonal. The effect of the geometry both on fluid flow characteristics (permeability and inertia parameter) and transport of aerosol particles is studied. Simulations are carried out at Reynolds numbers ranging from 0.001 and 100. The transport of solid particle (size 0.2, 2 and 10 micron) with different temperatures is also analyzed.

Turbidimetric flow analysis.

BRIENZA, S. M. B.; KRUG. F. J.; TORRES NETO, J. A. G.; NOGUEIRA, A. R. de A.; ZAGATTO, E. A. G.
Fonte: Journal of Flow Injection anality, v.10, n.2, p.187-194, 1993. Publicador: Journal of Flow Injection anality, v.10, n.2, p.187-194, 1993.
Tipo: Artigo em periódico indexado (ALICE)
Português
Relevância na Pesquisa
46.01815%
Historical development. Potentialities and limitations of turbimetric methods in flow analysis are revisited, with emphasis to nucleation rate. Main applications are presented and guidelines for systems design are suggested.; 1993; Resumo.

An investigation of the flow along and induced vibration of long cylinders.

Berera, Federico L.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2005 Português
Relevância na Pesquisa
36.24087%
An investigation of the interaction between the vibration of a cable towed under water and the flow developing in the vicinity of a slender cylindrical structure in axial flow, and departing from axial flow, is presented. The modal characteristics of a towed cable are discussed and mode shapes for the motion of a neutrally buoyant cable towed in a viscous fluid are determined. The flow past static cylindrical structures, with shapes representative of the mode shapes identified, is then observed in flow visualisation experiments. More specifically, the structures forming in the flow past circular cross-section cylinders in axial flow and near-axial flow, and past cylinders featuring a sudden departure from axial flow are investigated. The turbulent boundary layer that forms on cylinders in axial flow essentially retains its identity when the cylinder is slightly yawed. The boundary layer thickness may grow to many cylinder radii, and large eddies of scales that exceed the cylinder radius are observed. When the cylinder in axial flow features a bend, and thus suddenly departs from being in axial flow, dominant streamwise structures are formed in the wake of the inclined portion of the cylinder. The formation of these structures generates a shear layer at the interface with the free stream flow...

Application of a Helmholtz resonator excited by grazing flow for manipulation of a turbulent boundary layer.

Ghanadi, Farzin
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2015 Português
Relevância na Pesquisa
36.252048%
In most industrial applications involving flow the Reynolds number is typically sufficiently high such that the boundary layer is turbulent. Flow instabilities within the turbulent boundary layer can result in an excessive drag penalty which is considered to be the main parameter affecting the aerodynamic efficiency in numerous applications including aircraft and pipelines. The aim of this research is manipulation of the turbulent boundary layer through the oscillatory flow created by a flow-excited Helmholtz resonator for the purpose of minimising the flow instabilities. Attention has been given here to a cylindrical Helmholtz resonator as a possible alternative flow control device. The energy required to activate the Helmholtz resonator comes from the grazing flow and it can be fitted to existing airframes with minimal manufacturing requirements. Hence it can potentially be an ideal solution for a wall-based flow control device. This research provides an insight into the behaviour of the flow in the vicinity of the resonator and assesses the capability of a flow-excited Helmholtz resonator for reduction of disturbances within the boundary layer. The excitation of flow in the vicinity of the Helmholtz resonator is associated with both the external pressure fluctuations within the turbulent boundary layer and the acoustic response of the resonator cavity. A model of the relationship between the pressure inside the cavity and the boundary layer was developed based on a momentum balance equation and combination of the vortex sheet with discrete vortex models. A parametric study of the resonator showed that when the orifice length is increased the pressure fluctuations within the resonator are reduced...

A study of the flow within shallow, narrow cavities at low Reynolds numbers.

Crook, Sarah Diane
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011 Português
Relevância na Pesquisa
36.257961%
This thesis investigates low speed three-dimensional cavity flows. The flow past cavities, gaps and steps is of interest to researchers because these features are found on nearly all vehicles. Most past studies of cavity aerodynamics are of two-dimensional representations and although the literature provides valuable fundamental information on two-dimensional models and flow descriptions, they are inadequate when it comes to defining three-dimensional cavity flow. The aim of this study is therefore to discover, by measurement and observation, the time-averaged three-dimensional structure of incompressible flow in an open rectangular cavity in a flat plate. Furthermore, the study will focus on asymmetries in the ensemble-averaged and transient flow. The above aims are addressed by experimental investigation. Experimental data are obtained at low speed in both wind and water tunnels. The free stream Reynolds numbers are 3.4 x 10⁵ in air and 4.3 x 10⁴ in water. The ratio of cavity length (in the direction of the flow) to width to depth is l:w:d=6:2:1. The first experiments are of flow visualisation in both a wind and water tunnel, followed by measurements of surface pressure in air. Lastly, the velocity field in and near the cavity is investigated using Particle Image Velocimetry (PIV) in water. The surface pressure data are presented as pressure coeficient distributions. PIV data are presented as two-component velocity vector fields and streamline patterns in cross sections of the cavity. The experimental results show that a thin shear layer forms at the upstream lip of the cavity...

Untersuchung über die Wertigkeit der Flussmessung mittels MRT in den Nierenarterien zur Beurteilung der seitengetrennten Nierendurchblutung bei Patienten mit Nierenarterienstenose. Ein Vergleich zur Nierenfunktionsszintigraphie; Evaluation of a new MRI-method for blood flow in renal artery stenosis. Comparisons with measurements of kidney function by clearance method and by scintigraphy

Giersch, Jenny Yuhko
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
36.244963%
Fragestellung. Es sollte untersucht werden, inwieweit die MR-Phasenkontrast-flussmessung ohne Kontrastmittel als nicht-invasive und nicht-nephrotoxische Methode zur Beurteilung der seitengetrennten Nierendurchblutung bei Nierenarterienstenose (NAS) und zur Detektion einer NAS im Vergleich zur Nierenfunktionsszintigraphie geeignet ist. Methoden. MR-Blutflussmessung in den Nierenarterien (nMR-Fluss) bei 13 Hypertonikern mit NAS (46-71 Jahre) und 6 Hypertonikern ohne Stenose (29-63 Jahre). Bei 12 Patienten mit NAS zusätzlich Bestimmung der Technetium-99m-MAG-3-Clearance jeder Niere durch Nierenfunktionsszintigraphie ohne Captopril und Berechnung des seitengetrennten effektiven renalen Blutflusses (ERB). Korrelation von nMR-Fluss, MAG3-Clearance und ERB. Prüfung auf signifikante Unterschiede zwischen NAS-Gruppe 1 (NAS = 0-29%, n = 21), NAS-Gruppe 2 (NAS = 30-69%, n = 8) und NAS-Gruppe 3 (NAS = 70-100%, n = 6) für alle Methoden. Bestimmung der Genauigkeit von nMR-Fluss, MAG3-Clearance und ERB zur Detektion einer NAS > / = 70% mit ROC-Kurve. Vergleich zwischen Ergebnissen von Patienten, die einen ACE-Hemmer und / oder AT2-Rezeptorantagonisten eingenommen hatten, und denen von übrigen Patienten. Vergleich zwischen Ergebnissen unter Einschluss aller Patienten und nach Ausschluss von chronischer Niereninsuffizienz (CN) (n = 6 Patienten). Bestimmung von weiteren klinischen Parametern: Alter...

Flow y rendimiento en corredores de marato??n

Fern??ndez Mac??as, Miguel ??ngel; Godoy-Izquierdo, D??bora; Jaenes S??nchez, Jos?? Carlos; Boh??rquez G??mez-Mill??n, Mar??a Roc??o; V??lez Toral, Mercedes
Fonte: Universidad de las Islas Baleares Publicador: Universidad de las Islas Baleares
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.260566%
El flow es un estado subjetivo intensamente positivo y placentero que, por sus dimensiones y caracter??sticas (e.g., equilibrio entre las de- mandas percibidas de la tarea y las habilidades personales para la acci??n requerida, objetivos claros, m??xima concentraci??n, elevado control percibido sobre la ejecuci??n, etc.), se asocia a un rendimiento superior en comparaci??n con las actuaciones normales. La literatura se??ala que se puede experimentar en diferentes contextos y actividades, incluido el deporte. El objetivo de este estudio fue doble: Por un lado, quisimos comprobar si maratonianos de dis- tinto nivel de rendimiento experimentan flow y las caracter??sticas de este fen??meno en este colectivo de deportistas, as?? como conocer si las experiencias de flow eran diferentes en tres situaciones deportivas: Entrenamientos y carreras en general, la mejor carrera recordada y la ??ltima carrera; por otro lado, quisimos explorar la posible relaci??n entre las experiencias de flow y las marcas esperadas y conseguidas por los corredores en las carreras mejor y ??ltima. Colaboraron voluntariamente en este estudio 170 maratonianos que corrieron el Marat??n de Sevilla 2010, los cuales completaron la Escala Breve de Flow (Godoy-Izquierdo...

Cardiac flow analysis using magnetic resonance imaging.

Wong, Kelvin Kian Loong
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009 Português
Relevância na Pesquisa
36.257961%
Many types of cardiac abnormality have an implication on blood flow. However, most present-day diagnostic modalities analyse myocardial structures and not the cardiac flow within to detect heart defects in vivo. Currently, various imaging modalities, such as echocardiography, single photon emission computed tomography (SPECT), positron emission tomography (PET), X-ray computed tomography (CT), and cardiac magnetic resonance imaging (CMRI) provide a non-invasive approach for scanning humans with heart abnormalities, and are utilised in the management of cardiac patients. There is a need to develop a visualisation system for analysing flow of blood within the human heart. Motional properties of blood can be measured against normal controls and patients with cardiac abnormalities in order to discover underlying cause of these flow phenomena. This can potentially extend medical knowledge of the defects and their hemodynamic behaviour. We characterise motion patterns of blood in the human heart and analyse the flow properties, by means of tracking, using a series of time dependent magnetic resonance images. An indication of flow vortices can be provided by numerical computation of vorticity values within the defined region of blood flow. The global estimation of parametric motion flow fields over the whole image provides useful information on the presence of vortices within the heart chamber that can be used to assess cardiac functions. In this study...

Flow and displacement of viscoplastic fluids in eccentric annuli.

Deawwanich, Thana
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2013 Português
Relevância na Pesquisa
36.244963%
In the construction of oil and gas well, improper displacement work (primary cementing job) may cause poor zonal isolation, cement channeling, remedial squeeze cementing, and thus lead to a severe problem. The leakage of the wellbore fluids and contamination of sensitive zones resulting from poor primary cementing job such as the Gulf of Mexico's oil spill in April 2010 has been the biggest disaster accidents for mankind history since then. The experimental flow system was developed for systematic study of both single-fluid flow and two-fluid displacement in eccentric annuli. This flow is relevant to the drilling operation and cementing operation in oil well completions, where drilling fluids are displaced from the annulus between the casing and the well bore by a series of spacer/wash fluids and cement slurries. The design of the system is based on the helical flow geometry, which is a combination of annular axial flow and tangential rotating flow in an annulus. The annular flow apparatus can be operated at various degrees of eccentricity and different angles of inclination to simulate the type of flows in oilfield drilling and cementing operations. A special feature of the flow system is that the inner pipe can be rotated during displacement...

Multicomutation flow system for spectrophometric total amido acids determination in plant material.

NOGUEIRA, A. R. de A.; OLIVEIRA, D. B.; CARAPELI, R.; FERRAZ, L. F. de M.; MARTELLI, P. B.
Fonte: In: INTERNATIONAL CONFERENCE FLOW ANALYSIS, 10., 2006, Porto. Proceedings... Porto: IAFA, 2006 Publicador: In: INTERNATIONAL CONFERENCE FLOW ANALYSIS, 10., 2006, Porto. Proceedings... Porto: IAFA, 2006
Tipo: Resumo em anais de congresso (ALICE) Formato: p.183
Português
Relevância na Pesquisa
46.06741%
To identify lhe nitrogen transportation forms and attain the control mechanism, the amount of free amino acids in different parts of lhe plant has to be determined. An automatic, fast and reliable procedure multicomutated flow system {1] has been developed for spectrophotometric analysis of totalamino acids in plant material. The method is suitable for routine analysis for a large number of samples of plant material. The flow manifold was designed with computer-controlled three-way solenoid valves for independent handling of sample and reagent solutions and a data acquisition system from a spectrophotometer, employed for signal measurements. The software for system control was performed bya program with use of a LabView platform INationallntruments) [2]. The detection reaction was based on the complexation of amino functional groups of amino acids by ninhydrin. It reacts with free a-amino groups, producing lhe colored ninhydrin chromophore called Ruhemann's purple IRP) IAm". = 570 nm; E = 22 000) [3]. The proposed detection system shows a linear range concentration up to 2.0 X 10-3 mal L-I with coefficient of variation of 1.1% (n = 101. Detection limits were estimated as 2.8 x 10-3 mal L-I at 99.7% confidence level for total amino acids. and a mean sampling rale of 30 determinations per hour was achieved.; 2006

Flow y rendimiento en corredores de maratón

Fernández Macías, Miguel Ángel; Godoy-Izquierdo, Débora; Jaenes Sánchez, José Carlos; Bohórquez Gómez-Millán, María Rocío; Vélez Toral, Mercedes
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2015 Português
Relevância na Pesquisa
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El flow es un estado subjetivo intensamente positivo y placentero que, por sus dimensiones y características (e.g., equilibrio entre las de- mandas percibidas de la tarea y las habilidades personales para la acción requerida, objetivos claros, máxima concentración, elevado control percibido sobre la ejecución, etc.), se asocia a un rendimiento superior en comparación con las actuaciones normales. La literatura señala que se puede experimentar en diferentes contextos y actividades, incluido el deporte. El objetivo de este estudio fue doble: Por un lado, quisimos comprobar si maratonianos de dis- tinto nivel de rendimiento experimentan flow y las características de este fenómeno en este colectivo de deportistas, así como conocer si las experiencias de flow eran diferentes en tres situaciones deportivas: Entrenamientos y carreras en general, la mejor carrera recordada y la última carrera; por otro lado, quisimos explorar la posible relación entre las experiencias de flow y las marcas esperadas y conseguidas por los corredores en las carreras mejor y última. Colaboraron voluntariamente en este estudio 170 maratonianos que corrieron el Maratón de Sevilla 2010, los cuales completaron la Escala Breve de Flow (Godoy-Izquierdo...

Historical analyses of debris flow disaster occurrences and of their scientific investigation in Brazil; ; ; ; Historical analyses of debris flow disaster occurrences and of their scientific investigation in Brazil

Kobiyama, Masato; Michel, Gean Paulo; Engster, Elisiele Cardozo; Paixão, Maurício Andrades
Fonte: Labor & Engenho; Labor & Engenho Publicador: Labor & Engenho; Labor & Engenho
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 24/12/2015 Português
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Considering the debris flow as highly-destructive flow of water and sediment mixture in a way where it is a gravity-governed continuous flow, the present paper conducted a Web survey of technical-scientific studies that treated these phenomena which occurred in Brazil during the period 1900-2014. Although the increase of occurrence from the 1990s caused the increase in the number of publication, there are still a small number of publications, especially in scientific journals. A historical analysis about Brazilian studies demonstrates an actual situation in Brazil and confirms various necessary and urgent actions. Among them, the more important actions are: (1) establishment of terminology and concept about debris flow in Brazil; (2) systematization of hydrometeorological monitoring and topographic survey; (3) registration of occurrences and data-base construction; and (4) development of woody debris flow researches.; ; ; ; Considering the debris flow as highly-destructive flow of water and sediment mixture in a way where it is a gravity-governed continuous flow, the present paper conducted a Web survey of technical-scientific studies that treated these phenomena which occurred in Brazil during the period 1900-2014. Although the increase of occurrence from the 1990s caused the increase in the number of publication...