Papers by Keyword: Meniscus

Abstract: In the solution growth method for silicon carbide (SiC) single-crystal fabrication, in-situ observations were performed inside the furnace to monitor the meniscus at the seed–solution interface. A meniscus formed at the contact between the seed crystal and the solution, and variations in the reflections on the solution surface enabled optical monitoring and control of this interface. The observed surface images were also dependent on the frequency of the induction heating. Computational fluid dynamics (CFD) simulations indicated that lowering the heating frequency causes an upward displacement of the solution surface at its central region, producing a locally elevated contact position between the seed crystal and the solution. These findings demonstrate that in-situ observation constitutes an effective approach for precise control of meniscus shape during solution growth of SiC single crystals.

Abstract: The microbond test was one of the methods to examine the interfacial shear strength (IFSS) value of fiber and polymer matrix. The meniscus angle that formed at both ends of the matrix is difficult to control while manufacturing the specimen for the microbond test. Therefore, the effect of meniscus angle must be evaluated. In this paper, we evaluated the impact of variations of the meniscus angle against the maximum von-mises stress and the IFSS value of the Typha fiber epoxy matrix by finite element method. The geometry of the microbond test specimen was modeled with 0.25 mm fiber radius, 2 mm fiber length, 1.75 mm embedded length of the matrix, and varied the meniscus angles with 22°, 30°, 45°, 60°, 75°, and 90°. The mesh type quad-dominated CAX4R is used on fiber and matrix, while quad COHAX4 is applied to the cohesive element between fiber and matrix. The constantly applied displacement was adjusted to the upper end of the fiber at 0.6 mm. The simulation results showed that the difference in maximum stress obtained in each model. Furthermore, that is not given much difference in IFSS value. It can be concluded that the meniscus angle affects the maximum von-mises stress but not too much-affected IFSS value of the fiber and epoxy matrix.

Abstract: The collapse of high aspect ratio features is a daunting challenge facing the semiconductor industry. The complex physics and dynamics that govern this process are not entirely understood. Through the use of optical video imaging we have observed pattern collapse in real time. It was found that the liquid meniscus reconfigures itself laterally along the length of the structure as opposed to the expected top-to-bottom drying. Herein, we report on our observations and the physics of drying high aspect ratio structures.

Abstract: Osteoarthritis is a degenerative disease of articular cartilageand meniscus that most experience in aged and obesity, always tend to grow up. Such bone surface degenerated will beirregular and has bone to grow called osteophyte. At moment making activities, the pain and the deformation of the knee joint are occurred thatcause decreasing quality of life. The deterioratedmeniscus has to encountersgradually changing the structureuntil it is not able to support the body weight. This paper proposes the preliminary studyof the knee jointbehavior, especially the meniscus during stand. Three dimensions (3-D) finite element (FE) model of the knee joint has constructed. This model consisted of femur, tibiaand meniscus without fibula.The external load were determined in each body weight and appliedon femur to evaluate maximum von-mises stress on the meniscus.The stress distribution on meniscus always occurs while exist the external load on the femur. The tendency of association between the external load and maximumstress was corresponding to that of the other author.

Abstract: Evaporating meniscus of ethanol and ethanol-based nanofluids (0.01vol.%) in micro-channels were experimentally studied. Visualisation and thermographic results of the stationary meniscus confined in high-aspect-ratio rectangular micro-channels (hydraulic diameters are 571 μm, 727 μm and 1454 μm, channel cross sectional aspect ratio is 20, 20, 10 respectively) were obtained. It was found that interface evaporation rate increases with heat flux. The meniscus interface becomes deformed when the evaporation rate increases. The use of nanofluids largely enhances the interface stability even though the particle volume fraction is at a very low level. Besides, a stick-slip and back-jump behaviour of the nanofluids meniscus was captured during the transition from stable to deformed interface. Moreover, sink effect at the liquid-vapour interface was discussed based on the IR results.

Abstract: Anterior Cruciate Ligament (ACL) is of the major knee ligament. A three dimensional model that reflects the geometric characteristics of the human ACL developed to explore and analyze finite element parameters such as contact pressure and stress distribution on ACL in response to complex loading conditions. Moreover, various cases studied such as cases involving and uninvolving ligament in order to obtain and analyze the stress and contact pressure relationship between ACL, meniscus and cartilage. It is known that the contact and friction caused by the ACL wrapping around the bone during knee motion played the role of transferring the force from the ACL to the bone, and had a direct effect on the stress distribution of the ACL. Thus, the project lead to better understand the mechanism of injury, to improve the design of ACL reconstruction using suitable material and optimizing rehabilitation protocols by investigation of contact pressure with and without ACL.

Abstract: Knee meniscal injuries account for the greatest number of surgical procedures performed by orthopaedic surgeons worldwide. Each year in excess of 400,000 operations are performed in Europe and over one million in the United States and yet no suitable replacement for the meniscus is available. Fibrocartilage tissue engineering holds great potential in the regeneration of meniscal tissue however current developments have been limited. Difficulties in imitating the anisotropic nature of the meniscus, patient specific geometry, attaining sterility assurance requirements remain as developmental challenges for meniscal scaffold devices. A novel approach was developed to rapidly form terminally sterilized pre-packaged scaffold templates into anatomically matched regenerative meniscal implants. Formed meniscal implants exhibited the structural and functional architecture of the native meniscus. Meniscal implants fabricated using this method displayed mechanical properties approaching to that of the native meniscus and imparted rotational stability. Fixation techniques influenced the biomechanical response of implants and 45S5 bioactive glass modification was found to enhance radio-opacity of the scaffold. Biocompatibility of the implant was confirmed using a fibroblast cell culture model.

Abstract: An automatic liquid manometer which operates on the basis of a position-detecting system is described. A slanting laser beam is directed to the meniscus of liquid in a glass tube manometer without a float and is reflected by the meniscus. The reflected spotlight is focused on a position-sensitive detector (PSD) through a lens. The application of external pressure to the manometer causes the position of the meniscus to change, and the pressure can be gotten indirectly by this position. The relationship of the output of PSD to the displacement of meniscus was investigated, and the fuzzy control rules were determined to make the meniscus back to its original position fast and stable. The system has been tested with good results.

Abstract: We have grown high-quality long cylindrical (12 mm thick) 4H-SiC bulk crystals by the meniscus formation technique, which was first applied for the solution growth of bulk SiC. It enabled long-term growth by suppressing parasitic reactions such as polycrystal precipitation around the seed crystal. In addition, we could control the growth angle from −22° to 61° by adjusting the meniscus height. The thickness of the grown cylindrical crystals was 12 mm, which is the largest reported until now, and corresponded to a growth rate of 0.6 mm/h. Smooth morphology growth was maintained on the (000-1) C-face. In cross-sectional transmission optical microscopy images, few solvent inclusions and voids were observed. XRD measurements revealed that the FWHM values of the grown crystals were almost the same as those of the seed crystal.

Abstract: The intervention means for rehabilitation of meniscus injury using artificial biomaterials were increasingly sophisticated, which provide brand new research directions for rehabilitation of meniscus injuries. However, it is difficult to select the desired implant due to existent a series of problems, including the biocompatibility, shape matching, adhesion, toughness, strength of artificial biological materials to human body in the process of specific practical application. Nowadays, main biological materials for meniscus injuries including hyaluronic acid, collagen, gelatin, poly hydroxyl acid, lactic acid, calcium Polyphosphate-accumulating, Polytetrafluoroethylene, carbon fiber reinforced polymer that is not absorbed, and so on. The stem cells were induced redirect directionally or gene modified by transforming growth factor beta 1. Make bone marrow mesenchymal stem cells differentiate into cartilage cells by adjusting the number of cell growth and differentiation, and being inoculated for biomaterial scaffold, which provides new research directions for meniscus injury rehabilitation.