Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease. The cannula insertion process plays an important role in DBS. The friction force during needle insertion influences the precision of the insertion and the degree of damage to the brain tissue. This paper proposes a method of longitudinal vibration assisted insertion to reduce the friction during insertion and improve the effects of the insertion. Cannulas were inserted into twenty eight pig brains at multiple frequencies and fixed amplitudes, and the resulting friction force was measured. On this basis, the LuGre model was used to analyze the friction force trend under vibration-assisted conditions. The frictional forces of vibration-assisted insertion with frequencies ranging from 200-1200 Hz and an amplitude of 1 μm were measured. The results show that the friction between the needle shaft and the tissue is smaller with vibration than without vibration. In this experiment, the friction is reduced by up to 24.43%. The friction force trend of vibration-assisted insertion conforms to the simulation results of the LuGre model.
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http://dx.doi.org/10.1016/j.medengphy.2020.10.003 | DOI Listing |
Sci Rep
December 2024
Nanyang Vocational College, Nanyang, 473000, China.
In the course of pipe jacking construction, the carrying-soil effect frequently arises, influenced by factors such as excavation unloading, ongoing disturbance from successive pipe sections, and the progressive accumulation of soil adhesion. The pipe jacking slurry serves as a critical agent for friction reduction and strata support, essential for the secure advancement of the construction process. This study introduces the Microbial-Induced Calcium Carbonate Precipitation (MICP) technology into the realm of pipe jacking slurry, aiming to enhance its friction-reduction capabilities and the stability of the soil enveloping the pipe.
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December 2024
State Key Laboratory of Shield Machine and Boring Technology, Zhengzhou, 450001, China.
This paper presents an analytical solution derived with force method for the internal forces in the ring lining of maglev train tunnels, which are typically in a circular section and shallowly buried with low vacuum air pressure in the lining. The model incorporates the vacuum pressure induced by the differences in air pressures outside and inside the lining, and the vacuum pressure is assumed to be the active load exerting to the outside of the lining. The model assumes the vertical overburden acting on the lining is proportional to the soil depth at every particular point along the tunnel lining circumference.
View Article and Find Full Text PDFACS Nano
December 2024
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
Nanometer-thick ultrathin coatings with superior mechanical strength and desirable lubricating and antifouling performance are critical for the miniaturization of implantable medical devices. However, integrating these properties at the nanoscale remains challenging due to the inherent trade-off between mechanical strength and hydration as well as limitations in coating thickness. In this work, we address these challenges by employing dual-function metal coordination to construct a ∼25 nm thick bilayer structure.
View Article and Find Full Text PDFBiomimetics (Basel)
December 2024
Devol Advanced Automation, Inc., Shenzhen 518101, China.
Direct-drive servo systems are extensively applied in biomimetic robotics and other bionic applications, but their performance is susceptible to uncertainties and disturbances. This paper proposes an adaptive disturbance rejection Zeta-backstepping control scheme with adjustable damping ratios to enhance system robustness and precision. An iron-core permanent magnet linear synchronous motor (PMLSM) was employed as the experimental platform for the development of a dynamic model that incorporates compensation for friction and cogging forces.
View Article and Find Full Text PDFBiomimetics (Basel)
December 2024
School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Worms are organisms characterized by simple structures, low energy consumption, and stable movement. Inspired by these characteristics, worm-like soft robots demonstrate exceptional adaptability to unstructured environments, attracting considerable interest in the field of biomimetic engineering. The primary challenge currently involves improving the motion performance of worm-like robots from the perspectives of actuation and anchoring.
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