Untethered, powered orthotics require an actuation system with power supply and control, transmission line and actuator. Fluid power has unmatched force-to-weight and power-to-weight compared to electromechanical systems, but it is unclear if those same advantages hold for small systems in the 10 to 100 W range. A systems analysis approach suggests that a fluid power system will be lighter than an electromechanical system with the same output power and efficiency if the fluid power is run at pressures over about 200 psi. A theoretical analysis of small bore cylinders suggests that eliminating the piston seal will result in a higher efficiency actuator if the clearance gap is small. A demonstration, battery powered electrohydraulic actuator assembled from off-the-shelf components had the force and power suited to a powered ankle orthosis, but is too large and too heavy, suggesting the need to develop custom components.
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http://dx.doi.org/10.1109/ICORR.2011.5975473 | DOI Listing |
Water Res
January 2025
School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong SAR, China. Electronic address:
Flow meters are commonly used in manholes to monitor the flow rate for sewer operation and management. However, the large-scale deployment of flow meters in a sewer system is cost-prohibitive due to their high costs and the need for frequent maintenance. This paper proposes a soft sensor that estimates flow rates based on water level measurements in a manhole.
View Article and Find Full Text PDFR Soc Open Sci
January 2025
Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, Hunan 410013, People's Republic of China.
DNA mixtures containing semen and vaginal fluid are common biological samples in forensic analysis. However, the analysis of semen-vaginal fluid mixtures remains challenging. In this study, to solve these problems, it is proposed to combine semen-specific CpG sites and closely related microhaplotype sites to form a new composite genetic marker (semen-specific methylation-microhaplotype).
View Article and Find Full Text PDFAdv Mater
January 2025
Institute for Advanced Materials & Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China.
Laboratory-scale spin-coating techniques are widely employed for fabricating small-size, high-efficiency perovskite solar cells. However, achieving large-area, high-uniformity perovskite films and thus high-efficiency solar cell devices remain challenging due to the complex fluid dynamics and drying behaviors of perovskite precursor solutions during large-area fabrication processes. In this work, a high-quality, pinhole-free, large-area FAPbI perovskite film is successfully obtained via scalable blade-coating technology, assisted by a novel bidirectional Marangoni convection strategy.
View Article and Find Full Text PDFSci Rep
January 2025
Computational Fluid Dynamics Laboratory, School of Mechanical Engineering, VIT, Vellore, 632014, India.
Stenosis causes the narrowing of arteries due to plaque buildup, which impedes blood flow and affects flow dynamics. This work numerically analyzes flow fluctuations in stenosed arteries under realistic physiological conditions (resting and exercise) and external body acceleration. The artery is inclined at angle , and blood rheology is modeled using a generalized power-law fluid.
View Article and Find Full Text PDFHeliyon
January 2025
Biomedical Engineering Department, College of Engineering and Technologies, Al-Mustaqbal University, Hillah, Iraq.
The optimization of heat transfer in various engineering applications, such as thermal management systems and energy storage devices, remains a crucial challenge. This study aims to investigate the potential of Casson-based Cu-HO nanofluids in enhancing free convection heat transfer within complex geometries. The research examines the free convection heat transfer and fluid flow characteristics of a Casson-based Cu-HO nanofluid within a semi-parabolic enclosure that includes a wavy corrugated cylinder.
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