The flapping motion of a flexible propulsor near the ground was simulated using the immersed boundary method. The hydrodynamic benefits of the propulsor near the ground were explored by varying the heaving frequency (...The flapping motion of a flexible propulsor near the ground was simulated using the immersed boundary method. The hydrodynamic benefits of the propulsor near the ground were explored by varying the heaving frequency (St) of the leading edge of the flexible propulsor. Propulsion near the ground had some advantages in generating thrust and propelling faster than propulsion away from the ground. The mode analysis and flapping amplitude along the Lagrangian coordinate were examined to analyze the kinematics as a function of the ground proximity (d) and St. The trailing edge amplitude (\(a_\mathrm{tail}\)) and the net thrust (\(\overline{{F}}_x\)) were influenced by St of the flexible propulsor. The vortical structures in the wake were analyzed for different flapping conditions.展开更多
Individuals who are unable to walk independently spend most of the day in a wheelchair.This population is at high risk for developing pressure injuries caused by sitting.However,early diagnosis and prevention of these...Individuals who are unable to walk independently spend most of the day in a wheelchair.This population is at high risk for developing pressure injuries caused by sitting.However,early diagnosis and prevention of these injuries still remain challenging.Herein,we introduce battery-free,wireless,multimodal sensors and a movable system for continuous measurement of pressure,temperature,and hydration at skin interfaces.The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity,a temperature sensor for measuring skin temperature,and a galvanic skin response sensor for measuring skin hydration levels.The movable system enables power harvesting,and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage.Experimental evaluations and numerical simulations of the devices,together with clinical trials for wheelchair patients,demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.展开更多
基金supported by the Creative Research Initiatives (Grant 2016-004749) program of the National Research Foundation of Korea (MSIP)
文摘The flapping motion of a flexible propulsor near the ground was simulated using the immersed boundary method. The hydrodynamic benefits of the propulsor near the ground were explored by varying the heaving frequency (St) of the leading edge of the flexible propulsor. Propulsion near the ground had some advantages in generating thrust and propelling faster than propulsion away from the ground. The mode analysis and flapping amplitude along the Lagrangian coordinate were examined to analyze the kinematics as a function of the ground proximity (d) and St. The trailing edge amplitude (\(a_\mathrm{tail}\)) and the net thrust (\(\overline{{F}}_x\)) were influenced by St of the flexible propulsor. The vortical structures in the wake were analyzed for different flapping conditions.
基金supported by the Technology Innovation Program(00144157,Development of Heterogeneous Multi-Sensor Micro-System Platform)funded By the Ministry of Trade,Industry&Energy(MOTIE,korea)and the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(no.2021R1A2C3008742)supported by the MSIT(Ministry of Science and ICT),Korea,under the Grand Information Technology Research Center support program(IITP-2022-2016-0-00318)supervised by the IITP(Institute for Information&communications Technology Planning&Evaluation)Z.X.acknowledges the support from the National Natural Science Foundation of China(Grant No.12072057).
文摘Individuals who are unable to walk independently spend most of the day in a wheelchair.This population is at high risk for developing pressure injuries caused by sitting.However,early diagnosis and prevention of these injuries still remain challenging.Herein,we introduce battery-free,wireless,multimodal sensors and a movable system for continuous measurement of pressure,temperature,and hydration at skin interfaces.The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity,a temperature sensor for measuring skin temperature,and a galvanic skin response sensor for measuring skin hydration levels.The movable system enables power harvesting,and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage.Experimental evaluations and numerical simulations of the devices,together with clinical trials for wheelchair patients,demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.
