Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to sol...Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to solve the problem, extensive research has been carried out to study the major factors wh1ch rnay affect stress deterrnlnation. They include the rock behaviour and the stress state. For rocks showing non-isotropic behaviour, the values of Young’s modulus and Poisson ratio vary with the orientation of loading and measurement. Stress condition in the rock affects the rock behaviour. Furtherrnore, the loading condition on rock samples durlng laboratory tests is different from in the field and therefore the determined e1astic constants may not represent the field condi tion. In general , the Young’s modulus may depend on the orientation, the loading path, the stress magnitude and the stress ratio. This paper examines in detail the effects of those factors, especially for rocks showing transversely isotropic behaviour. It is found that the discrepancy of stress results from field measurernents in this type of rock is mainly due to over simplification of the rock behavior and inadequate use of elastic constants of the rock during stress calculation. A case study is given,which indicates the significance of these factors and demonstrates the proper procedure for stress calculation from measurements.展开更多
Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity ...Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube.展开更多
The phenomenon of hysteresis of contact angle is an important topic subject to a long time of argument.A simple hydrostatic model of sessile drops under the gravity in combination with an ideal surface roughness model...The phenomenon of hysteresis of contact angle is an important topic subject to a long time of argument.A simple hydrostatic model of sessile drops under the gravity in combination with an ideal surface roughness model is used to interpret the process of drop volume increase or decrease of a planar sessile drop and to shed light on the contact angle hysteresis and its relationship with the solid surface roughness. With this model, the advancing and receding contact angles are conceptually explained in terms of equilibrium contact angle and surface roughness only,without invoking the thermodynamic multiplicity. The model is found to be qualitatively consistent to experimental observations on contact angle hysteresis and it suggests a possible way to approach the hysteresis of three-dimensional sessile drops.展开更多
A novel saline-tolerant bacterium Bacillus circulans WZ-12 was evaluated for its potential to degrade four chlorinated hydrocarbons under saline conditions. CHECl2 was effectively degraded by Bacillus circulans WZ-12 ...A novel saline-tolerant bacterium Bacillus circulans WZ-12 was evaluated for its potential to degrade four chlorinated hydrocarbons under saline conditions. CHECl2 was effectively degraded by Bacillus circulans WZ-12 cells in the medium containing NaCl concentrations ranging from 5 g.L^-1 to 10 g-L^-1, and the maximum degradation efficiency （85%） was achieved at NaCl concentration of 10 g.L^-1. Similarly, Bacillus circulans WZ-12 was able to degrade CH2BrCl, C2H4Cl2, and C2H2Cl2 in the presence of 10 g NaCl per liter within 24 h. Cells of Bacillus circulans WZ-12 grown in minimal salt medium contained low levels of glycine betaine （GB）, but GB levels were 3- to 5-fold higher in cells grown in media with high salt. Kinetic analysis revealed that biodegradation of the four chlorinated hydrocarbons was concentration dependent and a linear inverse correlation （R2= 0.85-0.94） was observed between the rate of biodegradation （V） and salt concentration from 5 g.L〈 to 60 g.L-1. The growing cells （in minimal salt medium） degraded approximately 50% of the CH2C12 within 24 h, whereas the resting cells （in physiological saline） degraded only 25% of the CH2C12 within 24 h and were inactive after 36 h cultivation. Biodegradation could be repeatedly performed for more than 192 h with more than 50% removal efficiency. Bacillus circulans WZ-12 grows well in an aqueous/oil system, hence, it is effective for the treatment of industriai efflu- ents that contain chlorinated hydrocarbons with high salt concentrations.展开更多
The role of viscosity coefficient(η′), coulomb coupling parameter(Γ) and dust mass on the growth of jeans mode is investigated in strongly coupled dusty plasma using equations of Generalized Hydrodynamics(GH) Model...The role of viscosity coefficient(η′), coulomb coupling parameter(Γ) and dust mass on the growth of jeans mode is investigated in strongly coupled dusty plasma using equations of Generalized Hydrodynamics(GH) Model. The novel aspect of this work is that the force arising due to electrostatic pressure caused by grain grain interaction has been included in the dynamics of dust particles. This force is found to play a significant role in counter balancing the self gravity effect, thereby reducing the growth rate of jeans instability. The present work may provide more physical insight in understanding the mechanisms behind formation of planetesimals, stars etc.展开更多
The present article concerns the continuum modelling of the mechanical behaviour and equilibrium shapes of two types of nano-scale objects： fluid lipid bilayer membranes and carbon nanostructures. A unified continuum...The present article concerns the continuum modelling of the mechanical behaviour and equilibrium shapes of two types of nano-scale objects： fluid lipid bilayer membranes and carbon nanostructures. A unified continuum model is used to handle four different ease studies. Two of them consist in representing in analytic form cylindrical and axisymmetric equilibrium configurations of single-wall carbon nanotubes and fluid lipid bilayer membranes subjected to uniform hydrostatic pressure. The third one is concerned with determination of possible shapes of junctions between a single-wall carbon nanotube and a fiat graphene sheet or another single-wall carbon nanotube. The last one deals with the mechanical behaviour of closed fluid lipid bilayer membranes （vesicles） adhering onto a fiat homogeneous rigid substrate subjected to micro-injection and uniform hydrostatic pressure.展开更多
文摘Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to solve the problem, extensive research has been carried out to study the major factors wh1ch rnay affect stress deterrnlnation. They include the rock behaviour and the stress state. For rocks showing non-isotropic behaviour, the values of Young’s modulus and Poisson ratio vary with the orientation of loading and measurement. Stress condition in the rock affects the rock behaviour. Furtherrnore, the loading condition on rock samples durlng laboratory tests is different from in the field and therefore the determined e1astic constants may not represent the field condi tion. In general , the Young’s modulus may depend on the orientation, the loading path, the stress magnitude and the stress ratio. This paper examines in detail the effects of those factors, especially for rocks showing transversely isotropic behaviour. It is found that the discrepancy of stress results from field measurernents in this type of rock is mainly due to over simplification of the rock behavior and inadequate use of elastic constants of the rock during stress calculation. A case study is given,which indicates the significance of these factors and demonstrates the proper procedure for stress calculation from measurements.
基金supported by the National Natural Science Foundation of China (Grant No. 40771026)the NSFC-RFBR project (Grant No. 40911120089, 08-05-92206 NSFCa)
文摘Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube.
文摘The phenomenon of hysteresis of contact angle is an important topic subject to a long time of argument.A simple hydrostatic model of sessile drops under the gravity in combination with an ideal surface roughness model is used to interpret the process of drop volume increase or decrease of a planar sessile drop and to shed light on the contact angle hysteresis and its relationship with the solid surface roughness. With this model, the advancing and receding contact angles are conceptually explained in terms of equilibrium contact angle and surface roughness only,without invoking the thermodynamic multiplicity. The model is found to be qualitatively consistent to experimental observations on contact angle hysteresis and it suggests a possible way to approach the hysteresis of three-dimensional sessile drops.
基金Supported by the National Natural Science Foundation of China （20977087, 20976165）, Zhejiang Provincial Key Science and Technology Project of China （2011C13023）, and Zhejiang Provincial Natural Science Foundation of China （Y5090155, Y5090054）.
文摘A novel saline-tolerant bacterium Bacillus circulans WZ-12 was evaluated for its potential to degrade four chlorinated hydrocarbons under saline conditions. CHECl2 was effectively degraded by Bacillus circulans WZ-12 cells in the medium containing NaCl concentrations ranging from 5 g.L^-1 to 10 g-L^-1, and the maximum degradation efficiency （85%） was achieved at NaCl concentration of 10 g.L^-1. Similarly, Bacillus circulans WZ-12 was able to degrade CH2BrCl, C2H4Cl2, and C2H2Cl2 in the presence of 10 g NaCl per liter within 24 h. Cells of Bacillus circulans WZ-12 grown in minimal salt medium contained low levels of glycine betaine （GB）, but GB levels were 3- to 5-fold higher in cells grown in media with high salt. Kinetic analysis revealed that biodegradation of the four chlorinated hydrocarbons was concentration dependent and a linear inverse correlation （R2= 0.85-0.94） was observed between the rate of biodegradation （V） and salt concentration from 5 g.L〈 to 60 g.L-1. The growing cells （in minimal salt medium） degraded approximately 50% of the CH2C12 within 24 h, whereas the resting cells （in physiological saline） degraded only 25% of the CH2C12 within 24 h and were inactive after 36 h cultivation. Biodegradation could be repeatedly performed for more than 192 h with more than 50% removal efficiency. Bacillus circulans WZ-12 grows well in an aqueous/oil system, hence, it is effective for the treatment of industriai efflu- ents that contain chlorinated hydrocarbons with high salt concentrations.
文摘The role of viscosity coefficient(η′), coulomb coupling parameter(Γ) and dust mass on the growth of jeans mode is investigated in strongly coupled dusty plasma using equations of Generalized Hydrodynamics(GH) Model. The novel aspect of this work is that the force arising due to electrostatic pressure caused by grain grain interaction has been included in the dynamics of dust particles. This force is found to play a significant role in counter balancing the self gravity effect, thereby reducing the growth rate of jeans instability. The present work may provide more physical insight in understanding the mechanisms behind formation of planetesimals, stars etc.
基金Supported by the Bulgarian Ministry of Education, Youth and Science under the Project "Science and Business" BG051PO001/3.3-05-001 within "Human Resources Development" Operational Program of the European Social Fund
文摘The present article concerns the continuum modelling of the mechanical behaviour and equilibrium shapes of two types of nano-scale objects： fluid lipid bilayer membranes and carbon nanostructures. A unified continuum model is used to handle four different ease studies. Two of them consist in representing in analytic form cylindrical and axisymmetric equilibrium configurations of single-wall carbon nanotubes and fluid lipid bilayer membranes subjected to uniform hydrostatic pressure. The third one is concerned with determination of possible shapes of junctions between a single-wall carbon nanotube and a fiat graphene sheet or another single-wall carbon nanotube. The last one deals with the mechanical behaviour of closed fluid lipid bilayer membranes （vesicles） adhering onto a fiat homogeneous rigid substrate subjected to micro-injection and uniform hydrostatic pressure.
