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Volumetric Flow (volumetric + flow)

Distribution by Scientific Domains
Medical Sciences60%

Terms modified by Volumetric Flow

  • volumetric flow rate
    		•

    Selected Abstracts

    Volumetric flow mapping for microvascular networks by bimodality imaging with light microscope and laser doppler imager

    MICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2004
    Ying Sun
    Abstract A method was developed to produce a composite image of microvascular networks with grayscales proportional to volumetric flows. Velocities in arterioles and venules were assessed with a high-resolution laser Doppler imager (LDI). The vascular structures were quantified from the micrograph with a computerized vessel detection algorithm. After registering the detected vascular network with the LDI scan, volumetric flows were calculated along the centerlines of the vessels. In vivo data were obtained from the hamster cheek pouch in 6 studies. Flow continuity of the flow map was evaluated by comparing the main flow (Q) with the sum of branch flows (Qs), averaging over the respective vessel segments incident to each bifurcation. The method was reproducible across the 6 studies with the correlation coefficient (r) between Qs and Q ranging from 0.913 to 0.986. In all, over 20,000 flow estimates from 360 vessel segments (24,160 ,m in diameter) at 166 bifurcations were analyzed. With flow normalized between 0 and 1, the linear regression yielded: Qs = 1.03 Q + 0.006; r = 0.952, n = 166, P < 0.0005. The bimodality imaging method exploits a large amount of velocity and diameter data, and therefore should be useful for studying heterogeneous flows in the microvasculature. Microsc. Res. Tech. 65:130,138, 2004. © 2004 Wiley-Liss, Inc. [source]

    Automated Volumetric Flow Quantification Using Angle-Corrected Color Doppler Image

    ECHOCARDIOGRAPHY, Issue 5 2004
    Beomjin Kim Ph.D.
    We have developed a fully automated method for measuring volumetric blood flow with angle-corrected blood velocity from a color Doppler image. By computing the blood flow vector through a conduit, the angle of incidence between the direction of ultrasound beam and the direction of blood flow can be measured to correct the underestimated blood velocity. This correction immediately contributes to the improvement of measurement accuracy. The developed method also enhances the conduit identification procedure that is one of the most important factors affecting the accuracy of volumetric measurement. To evaluate the validity of the developed algorithm, experimental studies had been applied to 21 healthy subjects and 10 patients. Volumetric flows were measured from a color Doppler image of the left ventricular outflow track, which were compared with blood volumes that were measured by traditional pulsed-wave (PW)-Doppler technique. The mean stroke volume difference between two methods was ,0.45 ± 11.7 (mean ± SD). The proposed algorithm is a viable method for determining blood flow volume in an automated fashion. (ECHOCARDIOGRAPHY, Volume 21, July 2004) [source]

    A new concept for an osmotic energy converter

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2001
    A. Seppälä
    Abstract A new concept for an osmosis power generation system is presented. While the power production of a conventional system is based on continuous, increasing volumetric flow of solution directed to a turbine, the new concept is based on the pressurizing of fluids by osmosis. Two different new concepts were studied. In the first case, the osmotic module consists of the osmotic membranes, fresh water and solution. In the second case, gas is included in the solution part of the module. Consequently, the new system without gas was found to result in more than 2.5 times higher power values than the conventional concept. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Municipal sludge degradation kinetic in thermophilic CSTR

    AICHE JOURNAL, Issue 12 2006
    Ángeles de la Rubia
    Abstract The performance of a pilot-scale continuous-flow stirred-tank reactor (CSTR) treating municipal sludge under thermophilic conditions has been studied. Two pilot-scale reactors (CSTR1 (175 L) and CSTR2 (850 L)) were operated at different hydraulic residence times (,: 40 to 15 days). The anaerobic sludge processes are generally affected by variations in the concentration of substrate (determined as influent volatile solids, VS) and volumetric flow, both of which lead to a modification in biomass concentration and VS removal efficiency. This unsteady-state situation is mathematically explained in terms of an autocatalytic kinetic model. The general kinetic equation in this model has been applied to experimental data obtained in CSTR1. The fit of the experimental data to the model was used to estimate kinetic parameters and the yield coefficients (,max, ,, YP/S). The estimated parameters were ,max: 0.175d,1, ,: 0.358, YP/S: 0.309 m3CH4/kgVS). These parameters were subsequently used to model the substrate utilization rate and the methane generation rate in CSTR2. The model with the estimated parameters was found to provide excellent results, and is satisfactory in describing the concentration of VS and the methane generation rate in an actual digestion plant. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]

    Volumetric flow mapping for microvascular networks by bimodality imaging with light microscope and laser doppler imager

    MICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2004
    Ying Sun
    Abstract A method was developed to produce a composite image of microvascular networks with grayscales proportional to volumetric flows. Velocities in arterioles and venules were assessed with a high-resolution laser Doppler imager (LDI). The vascular structures were quantified from the micrograph with a computerized vessel detection algorithm. After registering the detected vascular network with the LDI scan, volumetric flows were calculated along the centerlines of the vessels. In vivo data were obtained from the hamster cheek pouch in 6 studies. Flow continuity of the flow map was evaluated by comparing the main flow (Q) with the sum of branch flows (Qs), averaging over the respective vessel segments incident to each bifurcation. The method was reproducible across the 6 studies with the correlation coefficient (r) between Qs and Q ranging from 0.913 to 0.986. In all, over 20,000 flow estimates from 360 vessel segments (24,160 ,m in diameter) at 166 bifurcations were analyzed. With flow normalized between 0 and 1, the linear regression yielded: Qs = 1.03 Q + 0.006; r = 0.952, n = 166, P < 0.0005. The bimodality imaging method exploits a large amount of velocity and diameter data, and therefore should be useful for studying heterogeneous flows in the microvasculature. Microsc. Res. Tech. 65:130,138, 2004. © 2004 Wiley-Liss, Inc. [source]