Armalcolite, a rare ceramic mineral and normally found in the lunar earth, was synthesized by solid-state step-sintering. The in situ phase-changed novel ceramic nanocrystals of Ca-Mg-Ti-Fe based oxide (CMTFOx), their chemical reactions and bonding with polydimethylsiloxane (PDMS) were determined by X-ray diffraction, infrared spectroscopy, and microscopy. Water absorption of all the CMTFOx was high. The lower dielectric loss tangent value (0.155 at 1 MHz) was obtained for the ceramic sintered at 1050 °C (S1050) and it became lowest for the S1050/PDMS nanocomposite (0.002 at 1 MHz) film, which was made by spin coating at 3000 rpm. The excellent flexibility (static modulus ≈ 0.27 MPa and elongation > 90%), viscoelastic property (tanδ = E″/E′: 0.225) and glass transition temperature (Tg: −58.5 °C) were obtained for S1050/PDMS film. Parallel-plate capacitive and flexible resistive humidity sensors have been developed successfully. The best sensing performance of the present S1050 (3000%) and its flexible S1050/PDMS composite film (306%) based humidity sensors was found to be at 100 Hz, better than conventional materials.
Despite of brittleness, Ceramic-on-Ceramic (CoC) hip joints are appealing to arthritic patients because of its low friction rate, high wear resistance and low risk of osteolysis. The objectives of the study were to review and summarize the performance of Alumina, Zirconia and their functional graded material (FGM) for artificial hip joints in vivo and vitro outcomes. The Method of the study was scoping review which focused on the peer reviewed journals containing with alumina, zirconia and alumina zirconia FGM to CoC hip prosthesis. Advanced version of Alumina CoC was found to have excellent hardness but low fracture toughness. Alumina CoC hip joints was found to have a revision rate as high as 5% after 20 clinical outcomes. Zirconia ceramic had high fracture toughness but relatively low hardness when compared to Alumina ceramic. Alumina-Zirconia FGM consists both high hardness (outer surface) and improved fracture toughness (inner core) which led to better mechanical and tribological properties. However, to date, there is still no literature was found to have long period of clinical outcomes. No article was screened carrying out durability study of Alumina/Zirconia FGM for CoC hip joints with appropriate tribological experiment. Alumina/ Zirconia FGM could be very effective for long term durability of CoC hip joints. Nevertheless, this FGM needs to be investigated under appropriate tribological tests considering dynamic loadings, dimension and shape of the joints, lubricant similar to synovial fluid and large number of cycles. The long term clinical outcomes also need to be published to increase its acceptability to young active patients.
This paper presents a fiber Bragg grating (FBG)-instrumented prosthetic silicone liner that provides cushioning for the residual limb and can successfully measure interface pressures inside prosthetic sockets of lower-limb amputees in a simple and practical means of sensing. The liner is made of two silicone layers between which 12 FBG sensors were embedded at locations of clinical interest. The sensors were then calibrated using a custom calibration platform that mimics a real-life situation. Afterward, a custom gait simulating machine was built to test the liner performance during an amputee's simulated gait. To validate the findings, the results were compared to those obtained by the commonly used F-socket mats. As the statistical findings reveal, both pressure mapping methods measured the interface pressure in a consistent way, with no significant difference (P-values ≥0.05). This pressure mapping technique in the form of a prosthetic liner will allow prosthetics professionals to quickly and accurately create an overall picture of the interface pressure distribution inside sockets in research and clinical settings, thereby improving the socket fit and amputee's satisfaction.
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