Fixed supports(rigid structures)and flexible supports(tensioned cable systems)are two main methods used in constructing photovoltaic power plants,and their construction technology has significant differences.This comp...Fixed supports(rigid structures)and flexible supports(tensioned cable systems)are two main methods used in constructing photovoltaic power plants,and their construction technology has significant differences.This comparative study assessed their environmental impacts on near-surface characteristics during constructing photovoltaic power plants in karst mountainous regions.Our findings revealed significant but different surface disturbances between these installation approaches.While both systems caused terrain modifications through foundation works and access road construction,the fixed support completely disturbed 100%of the construction area compared to<30%disturbance from flexible supports.Compared with the original ground,fixed support caused approximately 22%increase in bedrock exposure rate,while decreased 5%for the flexible support.Additionally,only 17%of the original vegetation coverage remained for the fixed support after construction,compared to 53%for the flexible support.The lower bedrock exposure rate and higher vegetation coverage of flexible support indicated that it had less surface disturbance area than fixed support.These results suggested that in ecologically sensitive karst terrains characterized by severe rocky desertification,challenging revegetation conditions,and low land productivity,flexible support photovoltaic technology represented a significantly less disruptive technology for minimizing surface disturbance and preserving fragile mountain ecosystems.展开更多
This paper is concerned with the generation of waves due to initial disturbances at the upper surface of a two-layer fluid, as the upper layer is covered by an inertial surface and the lower layer extends infinitely d...This paper is concerned with the generation of waves due to initial disturbances at the upper surface of a two-layer fluid, as the upper layer is covered by an inertial surface and the lower layer extends infinitely downwards. The inertial surface is composed of thin but uniform distribution of non-interacting material. In the mathematical analysis, the Fourier and Laplace transform techniques have been utilized to obtain the depressions of the inertial surface and the interface in the form of infinite integrals. For initial disturbances concentrated at a point, the inertial surface depression and the interface depression are evaluated asymptotically for large time and distance by using the method of stationary phase. They are also depicted graphically for two types of initial disturbances and appropriate conclusions are made.展开更多
In this context,a testing system to understand rock fracturing processes induced by different dynamic disturbances under true triaxial compression was developed.The system is mainly composed of a static loading subsys...In this context,a testing system to understand rock fracturing processes induced by different dynamic disturbances under true triaxial compression was developed.The system is mainly composed of a static loading subsystem,a dynamic loading subsystem,a specimen box subsystem,and a data measurement subsystem.The static loading subsystem uses low stiffness loss frame structure technology,which greatly improves the frame stiffness in the three principal stress directions(up to 20 GN/m)and ensures the demand of the disturbance experiment in both the prepeak and postpeak stages.The disturbance loads with frequency of 0e20 Hz and stress level of 0e30 MPa were applied using large flow parallel oil source technology characterized with high heat dissipation efficiency.For the disturbance loads with frequency of 100e500 Hz and stress level of 0e30 MPa,they were realized by using high-frequency and centimeter-per-second-scale low-speed disturbance rod technology.Three rigid self-stabilizing specimen boxes were utilized to provide support for the specimen and deformation sensors,ensuring the stability and accuracy of the data obtained.To verify the performance of the true triaxial test system,disturbance experiments were conducted on granite specimens.The results show that the experimental device satisfies the requirements of original design,with an excellent repeatability and reliable testing results.展开更多
Since the beginning of the systematic study of wear,many classification schemes have been devised.However,though covering the whole field in sum,they stay only loosely connected to each other and do not build a comple...Since the beginning of the systematic study of wear,many classification schemes have been devised.However,though covering the whole field in sum,they stay only loosely connected to each other and do not build a complete general picture.To this end,here we try to combine and integrate existing approaches into a general simple scheme unifying known wear types into a consistent system.The suggested scheme is based on three classifying criterions answering the questions“why”,“how”and“where”and defining a 3-D space filled with the known wear types.The system can be used in teaching to introduce students to such complex phenomena as wear and also in engineering practice to guide wear mitigation initiatives.展开更多
基金supported by Technology Project of Power Construction Corporation of China(DJ-ZDXM-2023-07)。
文摘Fixed supports(rigid structures)and flexible supports(tensioned cable systems)are two main methods used in constructing photovoltaic power plants,and their construction technology has significant differences.This comparative study assessed their environmental impacts on near-surface characteristics during constructing photovoltaic power plants in karst mountainous regions.Our findings revealed significant but different surface disturbances between these installation approaches.While both systems caused terrain modifications through foundation works and access road construction,the fixed support completely disturbed 100%of the construction area compared to<30%disturbance from flexible supports.Compared with the original ground,fixed support caused approximately 22%increase in bedrock exposure rate,while decreased 5%for the flexible support.Additionally,only 17%of the original vegetation coverage remained for the fixed support after construction,compared to 53%for the flexible support.The lower bedrock exposure rate and higher vegetation coverage of flexible support indicated that it had less surface disturbance area than fixed support.These results suggested that in ecologically sensitive karst terrains characterized by severe rocky desertification,challenging revegetation conditions,and low land productivity,flexible support photovoltaic technology represented a significantly less disruptive technology for minimizing surface disturbance and preserving fragile mountain ecosystems.
基金Supported by the DST Research Project No.SR/SY/MS:521/08and CSIR,New Delhi
文摘This paper is concerned with the generation of waves due to initial disturbances at the upper surface of a two-layer fluid, as the upper layer is covered by an inertial surface and the lower layer extends infinitely downwards. The inertial surface is composed of thin but uniform distribution of non-interacting material. In the mathematical analysis, the Fourier and Laplace transform techniques have been utilized to obtain the depressions of the inertial surface and the interface in the form of infinite integrals. For initial disturbances concentrated at a point, the inertial surface depression and the interface depression are evaluated asymptotically for large time and distance by using the method of stationary phase. They are also depicted graphically for two types of initial disturbances and appropriate conclusions are made.
基金This study was financially supported by the National Natural Science Foundation of China(Grant No.51839003),for which we are grateful.
文摘In this context,a testing system to understand rock fracturing processes induced by different dynamic disturbances under true triaxial compression was developed.The system is mainly composed of a static loading subsystem,a dynamic loading subsystem,a specimen box subsystem,and a data measurement subsystem.The static loading subsystem uses low stiffness loss frame structure technology,which greatly improves the frame stiffness in the three principal stress directions(up to 20 GN/m)and ensures the demand of the disturbance experiment in both the prepeak and postpeak stages.The disturbance loads with frequency of 0e20 Hz and stress level of 0e30 MPa were applied using large flow parallel oil source technology characterized with high heat dissipation efficiency.For the disturbance loads with frequency of 100e500 Hz and stress level of 0e30 MPa,they were realized by using high-frequency and centimeter-per-second-scale low-speed disturbance rod technology.Three rigid self-stabilizing specimen boxes were utilized to provide support for the specimen and deformation sensors,ensuring the stability and accuracy of the data obtained.To verify the performance of the true triaxial test system,disturbance experiments were conducted on granite specimens.The results show that the experimental device satisfies the requirements of original design,with an excellent repeatability and reliable testing results.
文摘Since the beginning of the systematic study of wear,many classification schemes have been devised.However,though covering the whole field in sum,they stay only loosely connected to each other and do not build a complete general picture.To this end,here we try to combine and integrate existing approaches into a general simple scheme unifying known wear types into a consistent system.The suggested scheme is based on three classifying criterions answering the questions“why”,“how”and“where”and defining a 3-D space filled with the known wear types.The system can be used in teaching to introduce students to such complex phenomena as wear and also in engineering practice to guide wear mitigation initiatives.
