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RISS 인기검색어
- 검색키워드
- 저자 : Noor Azuan Abu Osman (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
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Optimization and Comparison of Typical Elastic Actuators in Powered Ankle-foot Prosthesis
Jingjing Liu,Noor Azuan Abu Osman,Mouaz Al Kouzbary,Hamza Al Kouzbary,Nasrul Anuar Abd Razak,Hanie Nadia Shasmin,Nooranida Arifin 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.1
Elastic actuators are broadly applied in the design of the powered ankle-foot prosthesis, so it is a significant task to select and optimize a suitable elastic actuator. Dynamic models of seven kinds of elastic actuators are constructed from a two-degrees-of-freedom vibration system in rotation. With input parameters from sound ankle data during walking, motor data, and the three-dimensional model of the proposed prosthesis, two objectives, which are to minimize the peak mechanical power and mean energy consumption power of the motor, respectively, are optimized by changing the parameters of elastic elements. Unidirectional parallel elastic actuator (UPEA) and UPEA with series spring (SE+UPEA) optimize nearly 75% compared to the direct-driver actuator (DDA) in minimizing the characteristic of peak mechanical power. When it comes to reducing mean energy consumption power, UPEA is also the best, and its performance is at least 15% better than those of the other four kinds of elastic actuators with effective optimization. Besides, features of torque and velocity on the driver end are also compared from elastic actuators to sound ankle. The comparison contributes to understanding the optimization mechanism of different elastic elements, and the optimized and compared performances of elastic actuators can be utilized as the selection basis in the design of the powered ankle-foot prosthesis.
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Nur Ain Iftitah Mohamad Razali,Sumit Pramanik,Noor Azuan Abu Osman,Zamri Radzi,Belinda Pingguan-Murphy 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.7
Bioactive ceramics such as hydroxyapatite (HA) can mimic the organic structure of human bone. HA was successfullysynthesized from animal bones, corals, and eggshells which have been studied for bone repairing treatment and as implantcoatings. This study aims to synthesize nanorod HA from cockle shells via two routes: calcination and the hydrothermalmethod. The raw cockle shells were converted to calcite by calcination method at 450 oC (CS450) and 800 oC (CS800) for 2 hrs. The calcite calcium carbonate samples were reacted with diammonium hydrogen phosphate and hydrothermally treated at110 oC. The pH of the solution was kept at 10.5 throughout the synthesis step by adding drops of ammonia. Product obtainedwas labelled as HA450 and HA800 containing HA powder. Presence of calcite phase in the raw cockle shells was characterizedby utilizing Thermogravimetric analysis (TGA), X-ray Diffraction (XRD) and Fourier transforms infrared spectrophotometer(FTIR) analyses and morphologically analyzed by Field emission scanning electron microscopy (FESEM). The best result wasobtained from the HA800 sample where nanoparticle with rod-like shape was observed (aspect ratio = 7) while needle-likeparticle was seen in HA450 sample (aspect ratio = 20). High purity HA was developed in HA800 sample while HA450 showedsmall presence of calcite phase. In vitro bioactivity test of HA powder samples incubated simulated body fluid (SBF) for 1, 3,8, 15 and 21 days showed high bioactivity in both samples by forming apatite agglomerate on the surfaces. Highermicrohardness strength was observed in HA800 compared to HA450, CS450 and CS800 sintered pellet samples.
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Ay Ching Hee,Mehdi Mehrali,Hendrik Simon Cornelis Metselaar,Mohammad Mehrali,Noor Azuan Abu Osman 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.6
Ferrite is an important ceramic material with magnetic properties that are useful in many types of electronic devices. In this study, structure and magnetic properties of nanostructured nickel zinc ferrite and magnesium copper zinc ferrite prepared by water-in-oil microemulsion were compared. Both ferrites samples demonstrated similar weight loss characteristics in TGA. The magnesium copper zinc ferrite showed a crystalline structure with an average crystallite size of 13.5 nm. However, nickel zinc ferrite showed an amorphous phase. Transmission electron micrographs showed agglomerated nanoparticles with an average crystallite size of 26.6 nm for magnesium copper zinc ferrite and 22.7 nm for nickel zinc ferrite. Magnesium copper zinc ferrite exhibited soft ferromagnetic bahaviour whereas nickel zinc ferrite showed superparamagnetic nature.
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