Quadriplegia is a neuromuscular disease that may cause varying degrees of functional loss in trunk and limbs.In such cases,head movements can be used as an alternative communication channel.In this study,a human–mach...Quadriplegia is a neuromuscular disease that may cause varying degrees of functional loss in trunk and limbs.In such cases,head movements can be used as an alternative communication channel.In this study,a human–machine interface which is controlled by human head movements is designed and implemented.The proposed system enables users to steer the desired movement direction and to control the speed of an output device by using head movements.Head movements of the users are detected using a 6 DOF IMUs measuring three-axis accelerometer and three-axis gyroscope.The head movement axes and the Euler angles have been associated with movement direction and speed,respectively.To ensure driving safety,the speed of the system is determined by considering the speed requested by the user and the obstacle distance on the route.In this context,fuzzy logic algorithm is employed for closed-loop speed control according to distance sensors and reference speed data.A car model was used as the output device on the machine interface.However,the wireless communication between human and machine interfaces provides to adapt this system to any remote device or systems.The implemented system was tested by five subjects.Performance of the system was evaluated in terms of task completion times and feedback from the subjects about their experience with the system.Results indicate that the proposed system is easy to use;and the control capability and usage speed increase with user experience.The control speed is improved with the increase in user experience.展开更多
For long-distance water conveyance shield tunnels in operation,the high internal water pressure may cause excessive deformation of composite linings,affecting their structural integrity and serviceability.However,the ...For long-distance water conveyance shield tunnels in operation,the high internal water pressure may cause excessive deformation of composite linings,affecting their structural integrity and serviceability.However,the deformation and failure characteristics of lining structures under internal water pressure are not well investigated in the literature,particularly for three-layer composite linings.This study presents an in situ experimental investigation on the response of two types of composite linings(i.e.separated and combined lining structures)subjected to internal pressures,in which a fiber optic nerve system(FONS)equipped with distributed strain and displacement sensing nerves was employed to monitor the performance of the two composite linings during testing.The experimental results clearly show that the damage of the tunnel lining under different internal pressures was mainly located in the self-compaction concrete layer.The separated lining structure responded more aggressively to the variations in internal pressures than the combined one.Moreover,two evaluation indices,i.e.radial displacement and effective stiffness coefficient,are proposed for describing the changes in the structural bearing performance.The effective stiffness coefficients of the two types of lining structures were reduced by 39.4%and 29.5%,respectively.Considering the convenience of field monitoring,it is suggested that the average strains at different layers can be used as characteristic parameters for estimating the health conditions of lining structures in service.The analysis results provide a practical reference for the design and health evaluation of water conveyance shield tunnels with composite linings.展开更多
Triboelectrification between a liquid and a solid is a common phenomenon in our daily life and industry.Triboelectric charges generated at liquid/solid interfaces have effects on energy harvesting,triboelectrification...Triboelectrification between a liquid and a solid is a common phenomenon in our daily life and industry.Triboelectric charges generated at liquid/solid interfaces have effects on energy harvesting,triboelectrification-based sensing,interfacial corrosion,wear,lubrication,etc.Knowing the amount of triboelectric charge transfer is very useful for studying the mechanism and controlling these phenomena,in which an accurate method is absolutely necessary to measure the triboelectric charge generated at the solid–liquid interface.Herein,we established a method for measuring the charge transfer between different solids and liquids.An equipment based on the Faraday cup measurement was developed,and the leakage ratio(r_(l))was quantified through simulation based on an electrostatic field model.Typical experiments were conducted to validate the reliability of the method.This work provides an effective method for charge measurement in triboelectrification research.展开更多
Scholte waves at the seafloor interface are generally identified by their velocity features and seismic fields,which are measured using ocean bottom seismometers and geophones.These methods are effective in cases wher...Scholte waves at the seafloor interface are generally identified by their velocity features and seismic fields,which are measured using ocean bottom seismometers and geophones.These methods are effective in cases where there is a considerable difference between the velocities of Scholte and acoustic waves in water.However,they are ineffective when the velocities of these two types of waves are close to each other.Thus,in this paper,a method based on acoustic pressure field measurement for identifying Scholte waves is proposed according to their excitation and propagation characteristics.The proposed method can overcome the limitations on the velocities of two types of waves.A tank experiment is designed and conducted according to the proposed method,and an ocean environment is scaled down to the laboratory size.Acoustic measurements are obtained along virtual arrays in the water column using a robotic apparatus.Experiments show that changes in Scholte wave amplitudes,depending on different source depths and propagation distances,are consistent with the theoretical results.This means that Scholte waves generated at the seafloor interface are successfully measured and identified in the acoustic pressure field.展开更多
基金the Scientific and Technological Research Council of Turkey(TUBITAK).
文摘Quadriplegia is a neuromuscular disease that may cause varying degrees of functional loss in trunk and limbs.In such cases,head movements can be used as an alternative communication channel.In this study,a human–machine interface which is controlled by human head movements is designed and implemented.The proposed system enables users to steer the desired movement direction and to control the speed of an output device by using head movements.Head movements of the users are detected using a 6 DOF IMUs measuring three-axis accelerometer and three-axis gyroscope.The head movement axes and the Euler angles have been associated with movement direction and speed,respectively.To ensure driving safety,the speed of the system is determined by considering the speed requested by the user and the obstacle distance on the route.In this context,fuzzy logic algorithm is employed for closed-loop speed control according to distance sensors and reference speed data.A car model was used as the output device on the machine interface.However,the wireless communication between human and machine interfaces provides to adapt this system to any remote device or systems.The implemented system was tested by five subjects.Performance of the system was evaluated in terms of task completion times and feedback from the subjects about their experience with the system.Results indicate that the proposed system is easy to use;and the control capability and usage speed increase with user experience.The control speed is improved with the increase in user experience.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.42225702 and 42077235)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX22_0162)the scientific research project of Guangdong Yue Hai Pearl River Delta Water Supply Co.,Ltd.The authors thank Guangqing Wei,Lixiang Jia,and Zhen Zhang,all of Suzhou Nanzee Sensing Co.,Ltd.,for their assistance in the tests.The valuable suggestions provided by Professor Baojun Wang,Nanjing University,are also gratefully acknowledged.
文摘For long-distance water conveyance shield tunnels in operation,the high internal water pressure may cause excessive deformation of composite linings,affecting their structural integrity and serviceability.However,the deformation and failure characteristics of lining structures under internal water pressure are not well investigated in the literature,particularly for three-layer composite linings.This study presents an in situ experimental investigation on the response of two types of composite linings(i.e.separated and combined lining structures)subjected to internal pressures,in which a fiber optic nerve system(FONS)equipped with distributed strain and displacement sensing nerves was employed to monitor the performance of the two composite linings during testing.The experimental results clearly show that the damage of the tunnel lining under different internal pressures was mainly located in the self-compaction concrete layer.The separated lining structure responded more aggressively to the variations in internal pressures than the combined one.Moreover,two evaluation indices,i.e.radial displacement and effective stiffness coefficient,are proposed for describing the changes in the structural bearing performance.The effective stiffness coefficients of the two types of lining structures were reduced by 39.4%and 29.5%,respectively.Considering the convenience of field monitoring,it is suggested that the average strains at different layers can be used as characteristic parameters for estimating the health conditions of lining structures in service.The analysis results provide a practical reference for the design and health evaluation of water conveyance shield tunnels with composite linings.
文摘Triboelectrification between a liquid and a solid is a common phenomenon in our daily life and industry.Triboelectric charges generated at liquid/solid interfaces have effects on energy harvesting,triboelectrification-based sensing,interfacial corrosion,wear,lubrication,etc.Knowing the amount of triboelectric charge transfer is very useful for studying the mechanism and controlling these phenomena,in which an accurate method is absolutely necessary to measure the triboelectric charge generated at the solid–liquid interface.Herein,we established a method for measuring the charge transfer between different solids and liquids.An equipment based on the Faraday cup measurement was developed,and the leakage ratio(r_(l))was quantified through simulation based on an electrostatic field model.Typical experiments were conducted to validate the reliability of the method.This work provides an effective method for charge measurement in triboelectrification research.
基金the National Natural Science Foundation of China(No.11474258)the State Key Laboratory of Acoustics(No.SKLA202206)。
文摘Scholte waves at the seafloor interface are generally identified by their velocity features and seismic fields,which are measured using ocean bottom seismometers and geophones.These methods are effective in cases where there is a considerable difference between the velocities of Scholte and acoustic waves in water.However,they are ineffective when the velocities of these two types of waves are close to each other.Thus,in this paper,a method based on acoustic pressure field measurement for identifying Scholte waves is proposed according to their excitation and propagation characteristics.The proposed method can overcome the limitations on the velocities of two types of waves.A tank experiment is designed and conducted according to the proposed method,and an ocean environment is scaled down to the laboratory size.Acoustic measurements are obtained along virtual arrays in the water column using a robotic apparatus.Experiments show that changes in Scholte wave amplitudes,depending on different source depths and propagation distances,are consistent with the theoretical results.This means that Scholte waves generated at the seafloor interface are successfully measured and identified in the acoustic pressure field.
