A filter cake is often formed between soil and concrete during casting concrete in the ground,such as constructions of diaphragm walls and bored piles.The present study aims to investigate the effect of the filter cak...A filter cake is often formed between soil and concrete during casting concrete in the ground,such as constructions of diaphragm walls and bored piles.The present study aims to investigate the effect of the filter cake on the shear behavior of the sand-concrete pile interface.A series of sand-concrete interface direct shear tests were performed with a large-direct shear apparatus while considering different roughness(I=0,10,20 and 30 mm)and filter cake thickness(Δh=0,5 and 10 mm).For a smooth interface without a filter cake,the shear stress-horizontal displacement curves showed a“softening”response.The peak shear strength and friction angle decreased exponentially with increasing theΔh.Whereas,for a rough interface withΔh=5 or 10 mm,the shear stress-horizontal displacement curves presented a“hardening”response.The peak strength,as well as friction angle,decreased linearly with increasing theΔh.Moreover,a critical roughness I_(cr)of 10 mm was observed in the tests without a filter cake.The interface shear strength initially increased with increasing I but gradually decreased when the I exceeded I_(cr).In addition,the filter cake could reduce the roughness sensitivity on shear strength.展开更多
We study the temperature T and the phase of the Josephson critical current I（Ф） by taking into account the roughness scattering effect at inerface in an f-wave superconductor （S）/Insulator layer （I）/f-wave supe...We study the temperature T and the phase of the Josephson critical current I（Ф） by taking into account the roughness scattering effect at inerface in an f-wave superconductor （S）/Insulator layer （I）/f-wave superconductor （S） junction. It is found that the Josephson critical currents in f-wave Sir-wave S, the barrier strength and the roughness strength at inerface always suppress the Andreev reflection. When α=β, the phase dependence of the Josephson current I（Ф） between two f-wave S is predicted to be sin Ф; particularly, when a α≠ β, the phase dependence of the Josephson current I（Ф） between two f-wave superconductors is not predicted to be sin Ф and with the barrier strength increasing, the period of the I（Ф） turns decrease.展开更多
Roughening the surfaces of zirconium alloy tubes by glass-bead peening has been shown to increase the CHF （critical heat flux） in pool-boiling of water. The increase in CHF attributed to surface roughening effect ha...Roughening the surfaces of zirconium alloy tubes by glass-bead peening has been shown to increase the CHF （critical heat flux） in pool-boiling of water. The increase in CHF attributed to surface roughening effect has been measured in pool-boiling experiments using small-diameter zirconium alloy tubes that have been glass-peened with different bead sizes, intensity and coverage. The CHF was found to correlate with the fractal roughness measured on the metal surfaces. In this study, the nucleate pool-boiling characteristics of a large diameter Zircaloy-2 CANDU~ calandria tube （outer diameter -132 mm） with a glass-peened outside surface were tested in a pool of water near saturation. The primary objective was to measure the wall temperature and heat flux in order to develop a representative nucleate pool-boiling curve for large-diameter tubes with a glass-peened outside surface. By comparing the experimental results with models （e.g., Rohsenow correlation）, a modified boiling correlation has been developed for a glass-peened surface of calandria tubes that includes a surface roughness parameter.展开更多
基金Projects(51978672,51878671)supported by the National Natural Science Foundation of ChinaProject(2017zzts159)supported by the Graduate Innovation Program of Central South University,China+1 种基金Project(HNTY2021K09)supported by the Open Research Project of the Hunan Tieyuan Civil Engineering Testing Co.Ltd.,China。
文摘A filter cake is often formed between soil and concrete during casting concrete in the ground,such as constructions of diaphragm walls and bored piles.The present study aims to investigate the effect of the filter cake on the shear behavior of the sand-concrete pile interface.A series of sand-concrete interface direct shear tests were performed with a large-direct shear apparatus while considering different roughness(I=0,10,20 and 30 mm)and filter cake thickness(Δh=0,5 and 10 mm).For a smooth interface without a filter cake,the shear stress-horizontal displacement curves showed a“softening”response.The peak shear strength and friction angle decreased exponentially with increasing theΔh.Whereas,for a rough interface withΔh=5 or 10 mm,the shear stress-horizontal displacement curves presented a“hardening”response.The peak strength,as well as friction angle,decreased linearly with increasing theΔh.Moreover,a critical roughness I_(cr)of 10 mm was observed in the tests without a filter cake.The interface shear strength initially increased with increasing I but gradually decreased when the I exceeded I_(cr).In addition,the filter cake could reduce the roughness sensitivity on shear strength.
基金Supported by the"333"Project Funds of Jiangsu Province of China,the National Natural Science Foundation of China under Grant No.20571029by the Program for Excellent Talents in Huangshi Institute of Technology
文摘We study the temperature T and the phase of the Josephson critical current I（Ф） by taking into account the roughness scattering effect at inerface in an f-wave superconductor （S）/Insulator layer （I）/f-wave superconductor （S） junction. It is found that the Josephson critical currents in f-wave Sir-wave S, the barrier strength and the roughness strength at inerface always suppress the Andreev reflection. When α=β, the phase dependence of the Josephson current I（Ф） between two f-wave S is predicted to be sin Ф; particularly, when a α≠ β, the phase dependence of the Josephson current I（Ф） between two f-wave superconductors is not predicted to be sin Ф and with the barrier strength increasing, the period of the I（Ф） turns decrease.
文摘Roughening the surfaces of zirconium alloy tubes by glass-bead peening has been shown to increase the CHF （critical heat flux） in pool-boiling of water. The increase in CHF attributed to surface roughening effect has been measured in pool-boiling experiments using small-diameter zirconium alloy tubes that have been glass-peened with different bead sizes, intensity and coverage. The CHF was found to correlate with the fractal roughness measured on the metal surfaces. In this study, the nucleate pool-boiling characteristics of a large diameter Zircaloy-2 CANDU~ calandria tube （outer diameter -132 mm） with a glass-peened outside surface were tested in a pool of water near saturation. The primary objective was to measure the wall temperature and heat flux in order to develop a representative nucleate pool-boiling curve for large-diameter tubes with a glass-peened outside surface. By comparing the experimental results with models （e.g., Rohsenow correlation）, a modified boiling correlation has been developed for a glass-peened surface of calandria tubes that includes a surface roughness parameter.
