The Experts below are selected from a list of 753 Experts worldwide ranked by ideXlab platform
L Xu - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of thermal contact conductance at low temperature based on Fractal Description
International Communications in Heat and Mass Transfer, 2006Co-Authors: Ruiping Xu, Haidong Feng, Lanping Zhao, L XuAbstract:Abstract An experimental investigation of thermal contact conductance was conducted with pressed pairs of aluminum alloy 5052 and stainless steel 304 over the low temperature range from 155 to 210 K, with nominal contact pressure from 1 to 7 MPa. The contact surfaces were prepared through bead blasting and characterized with the Fractal dimension D and the parameter G of the Weierstrass–Mandelbrot function. The range of Fractal dimension is 1.59–1.86 for aluminum and 1.56–1.92 for stainless steel. And the parameter G is in the magnitude of 10−7 m. From the measured results, thermal contact conductance over this temperature range (155–210 K) is less than that near or above room temperature (T > 300 K). The load sensitivity at low temperature is less than that at room temperature. The smaller Fractal dimension D characterizes the rougher surface when G is on the same magnitude and results in the smaller value of the contact conductance and insensitivity to the contact pressure.
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Fractal Description of thermal contact resistance between rough surfaces at low temperature
Proceedings of the Twentieth International Cryogenic Engineering Conference (ICEC20), 2005Co-Authors: Rang Xu, H D Feng, L Xu, L P ZhaoAbstract:Publisher Summary Complex scientific instruments such as the space infrared detective facility or miniature thermal contact switch apparatus in satellite are often cooled through bolted or pressed links to their refrigeration systems. When two rough nominally flat surfaces are brought together under load, the discrete real contact points impede the heat flow through contact surfaces and result in the temperature drop and thermal contact resistance (TCR) at the interface. This chapter uses the Cantor set Fractal theory to describe the surface morphology of the interface and the Fractal TCR network model is obtained based on the elastic–plastic theory. This model considers the volume conservation of plastically deformed materials and the constriction resistance of asperities. It is concluded from the model that the asperities of the contact interface are deforming from plastically to elastically under normal load. The simulated results are in good agreement with the experimental results at low temperature. This model provides a new way to study the phenomenon of TCR.
T Kronrod - One of the best experts on this subject based on the ideXlab platform.
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the Fractal Description of seismicity
Geophysical Journal International, 2009Co-Authors: G Molchan, T KronrodAbstract:SUMMARY The stable estimation of multiFractal characteristics of seismicity is considered. The data are world and accessible regional catalogues of m ≥ 2–4 events. Our attention is focused on the range of scales in which the Renyi functionals admit of scale-invariant behaviour. We find that the stable Fractal analysis of hypocentres is generally difficult. As to epicentres, we have carried out a stable analysis for seven regions worldwide in the range of scales 1–1.7 decades. The estimates of generalized dimensions admit of tectonic interpretation.
Zhongxiao Peng - One of the best experts on this subject based on the ideXlab platform.
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the use of the Fractal Description to characterize engineering surfaces and wear particles
Wear, 2003Co-Authors: Chengqing Yuan, J Li, Zhongxiao PengAbstract:Fractals can be extremely useful when applied to tribology. Obtaining Fractal Descriptions of engineering surfaces and wear particles requires surface topography information to be measured, digitized and processed. Such procedures can be rigorous. This article compares various methods to calculate profile and surface Fractal dimension. Profile Fractal dimension is computed using three available methods, corresponding to the yard-stick, the power spectrum and the structure function method. The precision of the three methods is analyzed and compared in this paper. Surface Fractal dimension is calculated using the slit island and the box counting method. Both profile Fractal dimension and surface Fractal dimension are used to describe TiN coating surfaces and wear particles.
D. Jonas - One of the best experts on this subject based on the ideXlab platform.
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Revisiting Pollock's drip paintings (Reply)
Nature, 2006Co-Authors: R. P. Taylor, A. P. Micolich, D. JonasAbstract:Replying to: K. Jones-Smith & H. Mathur reply Our use^ 1 of the term 'Fractal'^ 2 is consistent with that by the research community. In dismissing Pollock's Fractals^ 1 , 3 because of their limited magnification range, Jones-Smith and Mathur^ 4 would also dismiss half the published investigations of physical Fractals^ 5 . On the basis of previous debates on limited-range Fractals^ 5 , 6 , a Fractal Description is particularly appropriate for Pollock's patterns because it is physically reasonable and because it is useful for condensing the Description of a complex geometry, as we now describe.
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Fractal Analysis: Revisiting Pollock's drip paintings (Reply)
Nature, 2006Co-Authors: Richard Taylor, A. P. Micolich, D. JonasAbstract:Replying to: K. Jones-Smith & H. Mathur reply Our use1 of the term 'Fractal'2 is consistent with that by the research community. In dismissing Pollock's Fractals1,3 because of their limited magnification range, Jones-Smith and Mathur4 would also dismiss half the published investigations of physical Fractals5. On the basis of previous debates on limited-range Fractals5,6, a Fractal Description is particularly appropriate for Pollock's patterns because it is physically reasonable and because it is useful for condensing the Description of a complex geometry, as we now describe.
G Molchan - One of the best experts on this subject based on the ideXlab platform.
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the Fractal Description of seismicity
Geophysical Journal International, 2009Co-Authors: G Molchan, T KronrodAbstract:SUMMARY The stable estimation of multiFractal characteristics of seismicity is considered. The data are world and accessible regional catalogues of m ≥ 2–4 events. Our attention is focused on the range of scales in which the Renyi functionals admit of scale-invariant behaviour. We find that the stable Fractal analysis of hypocentres is generally difficult. As to epicentres, we have carried out a stable analysis for seven regions worldwide in the range of scales 1–1.7 decades. The estimates of generalized dimensions admit of tectonic interpretation.
