The behavior of Taylor-Couette （TC） flow has been extensively studied. However, no suitable torque prediction models exist for high-capacity fluid machinery. The Eckhardt-Grossmann-Lohse （EGL） theory, derived base...The behavior of Taylor-Couette （TC） flow has been extensively studied. However, no suitable torque prediction models exist for high-capacity fluid machinery. The Eckhardt-Grossmann-Lohse （EGL） theory, derived based on the Navier-Stokes equations, is proposed to model torque behavior. This are the significant energy theory suggests that surfaces transfer interfaces between cylinders and annular flow. This study mainly focuses on the effects of surface texture on momentum transfer behavior through global torque measurement. First, a power-law torque behavior model is built to reveal the relationship between dimensionless torque and the Taylor number based on the EGL theory. Second, TC flow appa- ratus is designed and built based on the CNC machine tool to verify the torque behavior model. Third, four surface texture films are tested to check the effects of surface texture on momentum transfer. A stereo microscope and three-dimensional topography instrument are employed to analyze surface morphology. Global torque behavior is measured by rotating a multi component dynamometer, and the effects of surface texture on the annular flow behavior are observed via images obtained using a high-speed camera. Finally, torque behaviors under four differentsurface conditions are fitted and compared. The experi- mental results indicate that surface textures have a remarkable influence on torque behavior, and that the peak roughness of surface texture enhances the momentum transfer by strengthening the fluctuation in the TC flow.展开更多
Objective:To explore the influence of blending learning on the critical thinking disposition among undergraduates.Methods:Two undergraduate classes majoring in Applied Psychology with similar level of critical thinkin...Objective:To explore the influence of blending learning on the critical thinking disposition among undergraduates.Methods:Two undergraduate classes majoring in Applied Psychology with similar level of critical thinking disposition were selected as the research subjects.Class A(106 students)was the experimental class,and class B(131 students)was the control class.During the research period of one semester(four months),the following measures were implemented for the two classes.The control class studied Developmental Psychology under the conventional teaching methods and procedures,while the experimental class studied Developmental Psychology according to the requirements and procedures of blending learning.The two classes were investigated with Critical Thinking Disposition Inventory-Chinese Version(CTDI-CV)at the beginning and end of the course.Results:At the beginning of the course,the total scores of CTDI-CV of the two classes were(217.33±14.90)and(218.31±16.29),respectively,with no significant difference(P>0.05).At the end of the course,the total scores of CTDI-CV of the experimental class and the control class were(237.84±17.53)and(224.22±17.52),respectively,and the difference was statistically significant(P<0.001).Conclusion:Blending learning may have a positive effect in improving the critical thinking disposition in undergraduates.展开更多
基金Supported by National Programs for Fundamental Research and Development of China(Grant Nos.2009CB724308,2015CB057302)National Science and Technology Major Project of China(Grant No.2013ZX06002002-017)
文摘The behavior of Taylor-Couette （TC） flow has been extensively studied. However, no suitable torque prediction models exist for high-capacity fluid machinery. The Eckhardt-Grossmann-Lohse （EGL） theory, derived based on the Navier-Stokes equations, is proposed to model torque behavior. This are the significant energy theory suggests that surfaces transfer interfaces between cylinders and annular flow. This study mainly focuses on the effects of surface texture on momentum transfer behavior through global torque measurement. First, a power-law torque behavior model is built to reveal the relationship between dimensionless torque and the Taylor number based on the EGL theory. Second, TC flow appa- ratus is designed and built based on the CNC machine tool to verify the torque behavior model. Third, four surface texture films are tested to check the effects of surface texture on momentum transfer. A stereo microscope and three-dimensional topography instrument are employed to analyze surface morphology. Global torque behavior is measured by rotating a multi component dynamometer, and the effects of surface texture on the annular flow behavior are observed via images obtained using a high-speed camera. Finally, torque behaviors under four differentsurface conditions are fitted and compared. The experi- mental results indicate that surface textures have a remarkable influence on torque behavior, and that the peak roughness of surface texture enhances the momentum transfer by strengthening the fluctuation in the TC flow.
文摘Objective:To explore the influence of blending learning on the critical thinking disposition among undergraduates.Methods:Two undergraduate classes majoring in Applied Psychology with similar level of critical thinking disposition were selected as the research subjects.Class A(106 students)was the experimental class,and class B(131 students)was the control class.During the research period of one semester(four months),the following measures were implemented for the two classes.The control class studied Developmental Psychology under the conventional teaching methods and procedures,while the experimental class studied Developmental Psychology according to the requirements and procedures of blending learning.The two classes were investigated with Critical Thinking Disposition Inventory-Chinese Version(CTDI-CV)at the beginning and end of the course.Results:At the beginning of the course,the total scores of CTDI-CV of the two classes were(217.33±14.90)and(218.31±16.29),respectively,with no significant difference(P>0.05).At the end of the course,the total scores of CTDI-CV of the experimental class and the control class were(237.84±17.53)and(224.22±17.52),respectively,and the difference was statistically significant(P<0.001).Conclusion:Blending learning may have a positive effect in improving the critical thinking disposition in undergraduates.
