1,721,448 research outputs found
A further assessment of interpolation schemes for window deformation in PIV
No full textWe have evaluated the performances of the following seven interpolation schemes used for window deformation in particle image velocimetry (PIV): the linear, quadratic, B-spline, cubic, sinc, Lagrange, and Gaussian interpolations. Artificially generated images comprised particles of diameter in a range 1.1 <= d(p) <= 10.0 pixel were investigated. Three particle diameters were selected for detailed evaluation: d(p) = 2.2, 3.3, and 4.4 pixel with a constant particle concentration 0.02 particle/pixel(2). Two flow patterns were considered: uniform and shear flow. The mean and random errors, and the computation times of the interpolation schemes were determined and compared
Thermo-Elastohydrodynamic Analysis of Connecting Rod Bearing in Internal Combustion Engine
No full textDesign of hybrid steel/composite circular plate cutting tool structures
No full textSubstituting composite structures for conventional metallic structures has many advantages because composite materials have both high specific stiffness and damping characteristics compared to conventional metallic materials. In this study, circular plate cutting tools which are used for rough machining of bearing sites in crankshafts or camshafts were designed with the fiber reinforced composite material to reduce tool mass and to improve the dynamic stiffness of circular plate cutting tools. The hybrid steel/composite circular plate cutting tool was analyzed by finite element method with respect to material types such as composite and foam, stacking angles of the composite, adhesive bonding thickness, and dimensions of the cutting tool. Also, the constrained damping characteristics of the tools were experimentally investigated with respect to the adhesive bonding thickness and material type such as composite and PVC foam. From the finite element analysis and experimental results, optimal design parameters for the hybrid steel/composite circular plate cutting tool were suggested. (C) 2006 Elsevier Ltd. All rights reserved
Micro PIV measurement of two-fluid flow with different refractive indices
No full textMicro particle image velocimetry (PIV) characterization of two-fluid flow in a microchannel was analysed focusing on the effect of differences in the refractive indices of the two fluids on the accuracy of the PIV data. In the present study, we first analysed the objective-imaging system used for two-fluid flow measurement, and then derived the precondition for measurement of a valid velocity profile across the two-fluid interface. A micro PIV experimental system was set up to measure the two-fluid flow inside a Y-shaped microchannel. Using this system, the two-fluid flow of two glycerol-water mixtures with different glycerol mass concentrations (phi) was measured for three cases (phi = 0 and phi = 0.2; phi = 0.1 and phi = 0.5; and phi = 0 and phi = 0.6). The resulting experimental data agreed well with numerical predictions
Wiring cost in the organization of a biological neuronal network
No full textTo find out the role of the wiring cost in the organization of the neuronal network of the nematode Caenorhabditis elegans, we build the spatial neuronal map of C elegans based on geometrical positions of neurons. We show that the number of interneuronal connections of the Euclidean length d decays exponentially with d, implying that the wiring cost, defined as the sum of the interneuronal distances, plays an important role in the actual neuronal network. Using the two methods to shuffle the neuronal network in systematic ways, the edge exchange and the vertex swapping, we show that positions of neurons are not randomly distributed but organized to reduce the wiring cost. Furthermore, we discuss the trade-off between the wiring cost and the performance of the network. (c) 2006 Elsevier B.V. All rights reserved.Ministry of Science and Technology through Korean Systems Biology Research Grant M10309020000-03B5002-00000
KOSEF ABRL Program Grant No. R14-2002-059-01002-0
Ministry of Science and Technology through the Nanoscopia Center of Excellence at Ajou Universit
Investigation of wall and space charges decay using pulse technique in AC plasma display panel
Full text linkUsing simple pulse technique, two kinds of cases in alternating current (ac) plasma display panel were investigated. One is the relationship between the wall charge decay and the discharge aging time. The other is the relationship between space charge decay and the application of pulse to the address electrode during sustain period. For the former case, the minimum sustain voltage depended on the priming particles within a short time range (100 mu s) of afterglow, then suddenly increased as the afterglow time increased. With a long time range (600 mu s) of afterglow, the minimum sustain voltage depended on the state of the wall charges and gradually increased as the afterglow time increased. From these results, a time scale for the wall charge decay was obtained as a function of the discharge aging time. For latter case, the space charge decay time was 5 mu s when there are no pulses applied to the address electrode. The space charge decay time was about 4 mu s due to the application of pulses to the address electrode
Korean family name distribution in the past
No full textWe empirically study the genealogical trees of ten families for about five centuries in Korea. Although each family tree contains only the paternal part, the family names of women married to the family have been recorded, which allows us to estimate roughly the family name distributions for the past five hundred years. Revealed is the fact that the unique Korean family name distribution, characterized by a logarithmic form of the cumulative distribution and an exponentially decaying rank-size plot often called the Zipf plot, has remained unchanged for a long time. We discuss the implications of our results within a recently suggested theoretical model and compare them with observations in other countries in which power-law forms are abundantly found
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