The Experts below are selected from a list of 12483 Experts worldwide ranked by ideXlab platform

Tung Thanh Bui - One of the best experts on this subject based on the ideXlab platform.

  • Corona based air-Flow using parallel discharge electrodes
    Experimental Thermal and Fluid Science, 2016
    Co-Authors: Van Thanh Dau, Thien Xuan Dinh, Tung Thanh Bui, Canh-dung Tran, Hoa Thanh Phan, Tibor Terebessy
    Abstract:

    Abstract A novel air-Flow generator based on the effect of ion wind has been developed by the simultaneous generation of both positive and negative ions using two electrodes of opposite polarity placed in parallel. Unlike the conventional unipolar-generators, this bipolar configuration creates an ion wind, which moves away from both electrodes and yields a very low net charge on the device. The electro-hydrodynamic behavior of air-Flow has been experimentally and numerically studied. The velocity of ion wind reaches values up to 1.25 m/s using low discharge current 5 μA with the kinetic conversion efficiency of 0.65% and the released net charge of −30 fA, 8 orders of magnitude smaller compared with the discharge current. Due to easy scalability and low net charge, the present configuration is beneficial to applications with space constraints and/or where neutralized discharge process is required, such as inertial fluidic units, Circulatory Flow heat transfer, electrospun polymer nanofiber to overcome the intrinsically instability of the process, or the formation of low charged aerosol.

  • bipolar corona discharge based air Flow generation with low net charge
    Sensors and Actuators A-physical, 2016
    Co-Authors: Van Thanh Dau, Thien Xuan Dinh, Tung Thanh Bui, Tibor Terebessy
    Abstract:

    Abstract In this paper, we report on a miniaturized device that can generate ion wind Flow with very low net charge. Both positive and negative ions are simultaneously generated from two sharp electrodes placed in parallel, connected to a single battery-operated power source. The two-electrode arrangement is symmetrical, where the electrode creating charged ions of one polarity also serves as the reference electrode to establish the electric field required for ion creation by the opposite electrode, and vice versa. The numerical simulation is carried out with programmable open source OpenFOAM, where the measured current-voltage is applied as boundary condition to simulate the electrohydrodynamics Flow. The air Flow inside the device is verified by eight hotwires embedded alongside the downstream channel. It was confirmed that the jet Flow generated in the channel has a linear relationship with the square root of the discharge current and its measured values agree well with simulation. The device is robust, ready-to-use and minimal in cost. These are important features that can contribute to the development of multi-axis fluidic inertial sensors, fluidic amplifiers, gas mixing, coupling and analysis. The proposed configuration is beneficial with space constraints and/or where neutralized discharge process is required, such as inertial fluidic units, Circulatory Flow heat transfer, electrospun polymer nanofiber to overcome the intrinsic instability of the process, or the formation of low charged aerosol for inhalation and deposition of charge particles.

Vivek V Buwa - One of the best experts on this subject based on the ideXlab platform.

  • experimental characterization of dense gas liquid Flow in a bubble column using voidage probes
    Chemical Engineering Journal, 2017
    Co-Authors: Parul Tyagi, Vivek V Buwa
    Abstract:

    Gas–liquid Flow in bubble columns under dilute Flow condition has been investigated widely. In the present work, we have characterized gas–liquid Flow in a pseudo 2D bubble column for a wide range of superficial gas velocities (UG = 1–30 cm·s-1) that cover dilute to dense Flow conditions. In-house developed voidage probes were used to measure local gas volume fraction fluctuations, which in turn were used to characterize dynamics of column-scale re-Circulatory Flow and bubble-scale Flow processes, under dilute-to-dense conditions. Importantly, the spatial distribution of internal composition of gas volume fraction, i.e. gas volume fraction contained in different bubble size groups, was measured. Further, the spatial distribution of chord length and bubble size was measured for a wide range of UG. With increase in UG, the low frequency oscillations caused by meandering bubble plume at lower UG were found to diminish and the fluctuations caused by bubble swarms were found to dominate under the dense Flow conditions. Using the time spent by the probe in each bubble, the bubble population was classified into different size groups and the gas volume fraction for each size group was measured. Under dense Flow conditions, small bubbles were seen to accumulate near column walls, as exhibited by wall peaking in gas volume fraction profiles and that large bubbles were found to Flow through the column centre. The results presented in this work are important to improve the understanding of dense gas–liquid Flow and also for rigorous validation of CFD models.

  • modelling of gas liquid gas liquid solid Flows in bubble columns experiments and cfd simulations
    Canadian Journal of Chemical Engineering, 2008
    Co-Authors: Mohan R Rampure, Vivek V Buwa, Vivek V. Ranade
    Abstract:

    Gas-liquid/gas-liquid-solid systems are widely used in the chemical process industry for a variety of applications. In the present work, we have characterized the dynamics of gas-liquid/gas-liquid-solid Flows in cylindrical bubble columns using experiments and CFD simulations. The low frequency oscillations corresponding to the local re-Circulatory Flow were characterized using wall pressure fluctuation measurements. Eulerian-Eulerian two-/three-phase simulations were carried out with a focus on characterizing the dynamic properties of gas-liquid/gas-liquid-solid Flows. The effects of superficial gas velocity, H/D ratio and solid loading on the dynamic and time-averaged Flow behavior were studied experimentally and computationally. The simulated results were compared with the experimental measurements. The results presented are useful for understanding the dynamics of gas-liquid/gas-liquid-solid Flows in bubble columns and provide a basis for further development of CFD models for three-phase systems.

Brant M Weinstein - One of the best experts on this subject based on the ideXlab platform.

  • long term time lapse fluorescence imaging of developing zebrafish
    Zebrafish, 2005
    Co-Authors: Makoto Kamei, Brant M Weinstein
    Abstract:

    A variety of different transgenic zebrafish lines have been generated expressing green fluorescent protein (GFP) or other fluorescent proteins in different organs and tissues, permitting dynamic visualization of development of these organs and tissues in living animals via time-lapse imaging. Although methods have been devised for shortto medium-term time-lapse imaging of transgenic zebrafish, these methods are not suitable for longer term imaging because of poor control over temperature, evaporation, and anoxia. We describe a new imaging chamber that provides continuously circulating Flow of warm, oxygenated aqueous media. We show that the chamber can be used for multiphoton time-lapse imaging of developing blood vessels in the trunk of Fli1-EGFP transgenic zebrafish for 5 days without developmental delay, loss of viability, or evident reduction in strength of Circulatory Flow. This imaging chamber provides an important new tool for long-term dynamic imaging of transgenic zebrafish.

  • angiogenic network formation in the developing vertebrate trunk
    Development, 2003
    Co-Authors: Sumio Isogai, Nathan D Lawson, Saioa Torrealday, Masaharu Horiguchi, Brant M Weinstein
    Abstract:

    We have used time-lapse multiphoton microscopy of living Tg(fli1:EGFP) y1 zebrafish embryos to examine how a patterned, functional network of angiogenic blood vessels is generated in the early vertebrate trunk. Angiogenic vascular sprouts emerge from the longitudinal trunk axial vessels (the dorsal aorta and posterior cardinal vein) in two spatially and temporally distinct steps. Dorsal aorta-derived sprouts form an initial primary network of vascular segments, followed by emergence of vein-derived secondary vascular sprouts that interact and interconnect dynamically with the primary network to initiate vascular Flow. Using transgenic silent heart mutant embryos, we show that the gross anatomical patterning of this network of vessels does not require blood circulation. However, our results suggest that Circulatory Flow dynamics play an important role in helping to determine the pattern of interconnections between the primary network and secondary sprouts, and thus the final arterial or venous identity of the vessels in the functional network. We discuss a model to explain our results combining genetic programming of overall vascular architecture with hemodynamic determination of Circulatory Flow patterns.

Koji Fumoto - One of the best experts on this subject based on the ideXlab platform.

  • temperature visualization and investigation inside evaporator of pulsating heat pipe using temperature sensitive paint
    Applied Thermal Engineering, 2019
    Co-Authors: Keiko Ishii, Koji Fumoto
    Abstract:

    Abstract The mechanism of pulsating heat pipe (PHP) is still unclear because of its complex thermal fluid property, and a few studies have measured the temperature distribution inside PHPs. In this study, the temperature distribution inside a PHP was visualized. Temperature-sensitive paint (TSP) was applied on the optical window and was excited using UV LED light. The luminescence intensity was captured using a CMOS camera. The fluid and wall temperatures inside the PHP were measured instantaneously, with an accuracy of 0.263 °C. The thermal Flow induced by evaporation and oscillation was captured. The temperature of working fluid adhering to the wall surface was lesser than the ambient temperature. When oscillatory Flow was generated, the temperature at an arbitrary point inside the channel fluctuated. In contrast, when Circulatory Flow was generated, the temperature in the channel became stable. Based on the frequency analysis, the Circulatory Flow showed the periodic property. Measured data was in qualitative agreement with known PHP properties. Temperature measurement by TSP is considered effective in evaluating the performance and Flow mechanism of PHPs.

Dervis Can Vural - One of the best experts on this subject based on the ideXlab platform.

  • tissue failure propagation as mediated by Circulatory Flow
    Biophysical Journal, 2020
    Co-Authors: Gurdip Uppal, Gokhan Bahcecioglu, Pinar Zorlutuna, Dervis Can Vural
    Abstract:

    Abstract Aging is driven by subcellular processes that are relatively well understood. However, the qualitative mechanisms and quantitative dynamics of how these micro-level failures cascade to a macro-level catastrophe in a tissue or organs remain largely unexplored. Here, we experimentally and theoretically study how cell failure propagates in an engineered tissue in the presence of advective Flow. We argue that cells secrete cooperative factors, thereby forming a network of interdependence governed by diffusion and Flow, which fails with a propagating front parallel to advective circulation.

  • tissue failure propagation as mediated by Circulatory Flow
    bioRxiv, 2020
    Co-Authors: Gurdip Uppal, Gokhan Bahcecioglu, Pinar Zorlutuna, Dervis Can Vural
    Abstract:

    Aging is driven by subcellular processes that are relatively well-understood. However the qualitative mechanisms and quantitative dynamics of how these micro-level failures cascade to a macro-level catastrophe in a tissue or organs remain largely unexplored. Here we experimentally and theoretically study how cell failure propagates in a synthetic tissue in the presence of advective Flow. We argue that cells secrete cooperative factors, thereby forming a network of interdependence governed by diffusion and Flow, which fails with a propagating front parallel to advective circulation.