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The article highlights a research study on consumer navigation behavior through the Web users?optimal Flow experiences in the online environments. The research study establishes the empirical groundwork for measuring Web users?Flo...
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The article highlights a research study on consumer navigation behavior through the Web users?optimal Flow experiences in the online environments. The research study establishes the empirical groundwork for measuring Web users?Flow experiences in the Web environment. The article proposes a comprehensive definition of Flow on the basis of Comprehensive Process (Flow) Model of Network Navigation, considering that the Flow concept is a multidimensional concept in the 搈ulti-activity?medium of the Web. Flow has been defined as a multi-dimensional and context-specific concept. Furthermore, the research article proposes that there are 10 Flow constructs (also called 搕he antecedents of Flow? along with the three states of Flow, namely, Perfect Flow, Imperfect-Intensive Flow, and Imperfect Flow. Consumer Behavior on the Web is studied using the Flow concept for three categories of Flow users, namely, Perfect and Imperfect-Intensive Flow (PIIF) users, Imperfect Flow (IF) users, and Non-Flow (NF) users. These users achieve Flow depending on 10 Flow-constructs and three Flow states. Empirical results suggest a direct relationship between the Flow states and the Flow user categories and between expected Web user in the future (EXPUSE) and the Flow user categories. This research study provides a basis for future researchers to study consumer navigation behavior on the Web using the Flow concept for three categories of Flow users through 10 Flow constructs and three Flow states. The research has significant implications for theory and practice.
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摘要 :
The article highlights a research study on consumer navigation behavior through the Web users' optimal Flow experiences in the online environments. The research study establishes the empirical groundwork for measuring Web users 'F...
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The article highlights a research study on consumer navigation behavior through the Web users' optimal Flow experiences in the online environments. The research study establishes the empirical groundwork for measuring Web users 'Flow experiences in the Web environment. The article proposes a comprehensive definition of Flow on the basis of Comprehensive Process (Flow) Model of Network Navigation, considering that the Flow concept is a multidimensional concept in the "multi-activity " medium of the Web. Flow has been defined as a multi-dimensional and context-specific concept. Furthermore, the research article proposes that there are 10 Flow constructs (also called "the antecedents of Flow") along with the three states of Flow, namely. Perfect Flow, Imperfect-Intensive Flow, and Imperfect Flow. Consumer Behavior on the Web is studied using the Flow concept for three categories of Flow users, namely, Perfect and Imperfect-Intensive Flow (PIIF) users, Imperfect Flow (IF) users, and Non-Flow (NF) users. These users achieve Flow depending on 10 Flow-constructs and three Flow states. Empirical results suggest a direct relationship between the Flow states and the Flow user categories and between expected Web user in the future (EXPUSE) and the Flow user categories. This research study provides a basis for future researchers to study consumer navigation behavior on the Web using the Flow concept for three categories of Flow users through 10 Flow constructs and three Flow states. The research has significant implications for theory and practice.
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This work presents an experimental and numerical study of pulsated Dean flow, three-dimensional pulsatile flow in a curved pipe. The numerical study is performed by CFD code (Fluent 6) in which a pulsated velocity field is imposed...
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This work presents an experimental and numerical study of pulsated Dean flow, three-dimensional pulsatile flow in a curved pipe. The numerical study is performed by CFD code (Fluent 6) in which a pulsated velocity field is imposed as an inlet condition. The experimental setup involves principally a "Scotch-yoke" pulsatile generator and a 90° bend. Laser Doppler Velocimetry (LDV) measurements have shown that the Scotch-yoke generator produces pure sinusoidal instantaneous mean velocities with a mean deviation of 3%. Visualizations by laser-induced fluorescence (LIF) and velocity measurements, coupled with the numerical results, have permitted analysis of the evolution of the swirling secondary flow structures that develop along the bend during the pulsation phase. These measurements were made for a range of stationary Reynolds number (300 ≤ Re_(st) ≤ 1200), frequency parameter (1 ≤ α = r_0 (ω/v)~(1/2) < 20), and two velocity components ratios (β = U_(max.osc)U_(st)). We observe satisfactory agreement between the numerical and experimental results. For high p, the secondary flow structure is modified by a Lyne instability and a siphon effect during the deceleration phase. The intensity of the secondary flow decreases as the parameter a increases during the acceleration phase. During the deceleration phase, under the effect of reverse flow, the secondary flow intensity increases with the appearance of Lyne flow.
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Overland flow in an ephemeral gully (EG) system includes the EG channel, rill and interrill sheet flows, which comprise an interconnected drainage network. There are abundant researches on the hydraulics of rill flow and interrill...
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Overland flow in an ephemeral gully (EG) system includes the EG channel, rill and interrill sheet flows, which comprise an interconnected drainage network. There are abundant researches on the hydraulics of rill flow and interrill sheet flow, as well as their relationships with soil detachment rates and sediment loads. Few studies have quantified the flow hydraulics of EG system which is highly related to the EG erosion and the development of better EG management strategies. Thus, two erosive rainfall intensities (50 and 100 mm h(-1)) and two slope gradients (15 degrees and 20 degrees) under different upslope and lateral inflow boundary conditions were employed to study the flow hydraulics of an EG system using simulated rainfall and inflow experiments. The results showed that flow velocity, shear stress, stream power and cross-sectional energy in the EG channel generally increased from the top to bottom of the slope with different trends and fluctuations under various inflow conditions. The flow hydraulic parameters of EG channel, rill, and interrill sheet flows all increased as rainfall intensity and slope increased. Flow regimes in the EG system were divided based upon the Reynolds number and Froude number. EG channel flow was classified as transitional to turbulent flow, rill flow was transitional, while sheet flows on interrill areas was laminar. From sheet flow to rill flow and EG channel flow, the flow regime gradually shifted from laminar and subcritical flow to turbulent and supercritical flow. The flow force, power and energy correspondingly increase as flow regime changed toward turbulent and supercritical. Good relationships between sediment load and flow hydraulic parameters were observed and flow shear stress was found to be best correlated with soil erosion of the EG system (R-2 = 0.92). This study quantitively mapped the flow hydraulics in the EG system and correlated these with erosion features, contributing to the development of process-based EG prediction models and better EG management strategies.
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In general, the computation of single phase subsonic mass velocity of gas flowing through a pipe requires a computerized iterative analysis. The equations for the friction factor for laminar and turbulent flow are used to obtain e...
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In general, the computation of single phase subsonic mass velocity of gas flowing through a pipe requires a computerized iterative analysis. The equations for the friction factor for laminar and turbulent flow are used to obtain explicit equations for the subsonic mass velocity as a function of the pressures at the ends of a pipe. Explicit equations for mass velocity are presented. Included within the equations is a heat transfer ratio, which can vary between 0 for adiabatic flow conditions to 1 for isothermal flow conditions. The use of this heat transfer ratio also enables the formulation of an explicit equation for the gas temperature along the pipe for nonisothermal flow conditions. The explicit equations eliminate the need for an iterative solution. Laboratory data are used to support the accuracy of the model.
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The development of a wing-tip vortex of a rectangular, square-tipped wing having a NACA 0012 airfoil at a chord Reynolds number Re-cw = 2 x 10(5), under the effect of synthetic jet actuation, was experimentally studied. Five contr...
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The development of a wing-tip vortex of a rectangular, square-tipped wing having a NACA 0012 airfoil at a chord Reynolds number Re-cw = 2 x 10(5), under the effect of synthetic jet actuation, was experimentally studied. Five control configurations were considered: case C1 with momentum coefficient C-mu = 0.001 and actuation frequency F+ = 0.075; case C2 with C-mu = 0.001 and F+ = 0.15; case C3 with C-mu = 0.001 and F+ = 0.3; case C4 with C-mu = 0.001 and F+ = 0.6; and case C5 with C-mu = 0.001 and F+ = 1.2. Under the most effective configuration, case C3, the vortex was stretched and appeared to be diffuse with a nearly 40% decrease in the peak circumferential velocity and 50% decrease in the core axial vorticity. The vortex core radius largely broadened suggesting that the lower-frequency control configuration allowed the synthetic jet to travel larger distances into the vortex bringing turbulent structures within its core resulting in increased mixing and subsequently a more diffuse vortex.
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Explosion suppression is often the preferred method of explosion attenuation in industry. The morphology development of suppression clouds is important for the design of necessary suppression systems. This paper presents a numeric...
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Explosion suppression is often the preferred method of explosion attenuation in industry. The morphology development of suppression clouds is important for the design of necessary suppression systems. This paper presents a numerical and experimental investigation of the growth of powder dispersion as it expands from a discharge nozzle. A Lagrangian stochastic particle-tracking approach and the renormalised group k -ε turbulence model are adopted in the flow field solver for the dispersed and continuous phases. The flow fields coupled with the particle interactions are predicted. The dispersion characteristics of the expansion of the powder cloud through a pipe for short intervals of time are investigated. This was compared with (1) captured images from experiments, (2) experimental data, and (3) results of previous simulations. Particle positions along the jet are presented. The effects of flow rate on the development of the cloud and a comparison with experimental results are also presented. It is noted that the coverage of the powder cloud can be controlled by the flow rate of the jet, and the developing length of the cloud is more influenced by the flow rate of jet flow than the developing width. The good qualitative agreements achieved are useful for further optimisation of product design.
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This numerical study reveals stable multi-eddy patterns of a steady axisymmetric air-water flow driven by the rotating bottom disk in a vertical sealed cylindrical container. As rotation strength Re increases, eddies emerge, coale...
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This numerical study reveals stable multi-eddy patterns of a steady axisymmetric air-water flow driven by the rotating bottom disk in a vertical sealed cylindrical container. As rotation strength Re increases, eddies emerge, coalesce, separate, and disappear in both air and water. The topological scenario varies with water volume fraction H-w according to the results obtained for Hw = 0.3, 0.5, and 0.8. Interesting features are: (a) zipper-like chains of air and water eddies forming as the interface bends and (b) bubble-ring air eddies existing in the Re ranges specified in the paper. The stability analysis, performed with the help of a novel efficient technique for two-fluid flows, shows that these multi-eddy motions are stable. The shear-layer instability develops as the interface approaches either the top or bottom of the container and some eddies vanish. The physical reasoning behind the eddy formation and the flow instability is provided. The results are of fundamental interest and can have applications in bioreactors.
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The flow condensation heat transfer coefficient of R134a inside two helical micro-fin tubes with outer diameter of 6.35 mm and helical angles of 18° and 28° respectively were experimentally studied at a high mass flux ranging fr...
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The flow condensation heat transfer coefficient of R134a inside two helical micro-fin tubes with outer diameter of 6.35 mm and helical angles of 18° and 28° respectively were experimentally studied at a high mass flux ranging from 500 to 1100 kg m~(-2) s~(-1). The condensation temperatures are 35℃, 40℃ and 45℃. and the vapor qualities ranges from 0.95 to 1.00 at the inlet section and from 0.00 to 0.05 at the outlet section. Experimental results show that there are annular and intermittent flow regimes inside the tube under experimental conditions, the ratio of annular flow region to the total heat transfer region is about 70%. The liquid film flow changes from rotational flow to coexistence of rotational and horizontal flows when the vapor quality is 0.475±0.08, 0.486±0.06 and 0.521 ±0.05, respectively and the corresponding saturation temperature is 35℃. 40℃ and 45℃. Based on the experimental data, the heat transfer coefficient increases with increasing mass flux and fin helical angle, and with decreasing saturation temperature and Reynolds number of cooling water. In addition, the heat transfer coefficient of annular flow is greater than that of intermittent flow, in other words, the heat transfer coefficient increases with increasing vapor quality. The heat transfer coefficient obtained at high mass flux was compared with the calculated data of some published correlations used at low mass flux. It was found that most correlations underestimate the experimental heat transfer coefficient inside the micro-fin tube, and these prediction deviation increases with increasing mass flux and fin helical angle. By introducing some dimensionless numbers as well as considering the flow mechanism of liquid film inside the tube, two heat transfer coefficient correlations were proposed based on the experimental data. The ratio of liquid film thickness to fin height was used to characterize whether the liquid film flow is rotational flow or coexistence of rotational and horizontal flows in the proposed correlation, which shows a better prediction accuracy with a mean deviation of less than 7.3%.
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In this work we study the asymptotic behavior of solutions of the incompressible two dimensional Euler equations in the exterior of a single smooth obstacle when the obstacle becomes very thin tending to a curve. We extend results...
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In this work we study the asymptotic behavior of solutions of the incompressible two dimensional Euler equations in the exterior of a single smooth obstacle when the obstacle becomes very thin tending to a curve. We extend results by Iftimie, Lopes Filho and Nussenzveig Lopes, obtained in the context of an obstacle tending to a point, see [D. Iftimie, M.C. Lopes Filho, H.J. Nussenzveig Lopes, Two dimensional incompressible ideal flow around a small obstacle, Comm. Partial Differential Equations 28 (1-2) (2003) 349-379].
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