Proceedings of JSPE Semestrial Meeting

Ceramic Matrix Composite (CMC) is an advanced material which is light and heat resistant. With these strength this material is expected to be used in the field of aerospace industry. CMC material is consist of ceramic fibers which have 3D woven structure embedded in a ceramic matrix. The physical properties of this material heavily depend on the orientations of the fibers. This paper presents a method for detecting defects of orientations of fibers in CMC. We detect these defects by directional distance method. In our aogorithm, at first we binarize the CT image of CMC material and apply directional distance method to the binarized image.

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Quasi-conformal parameterization is important in many CG and CAD applications. It is well-known that solving the Beltrami system {em with} natural boundary conditions gives a least-squares quasi-conformal map. In this research, we propose a novel formulation of least-squares quasi-conformal parameterization based on classical differential geometry tools and a formula of variational calculus. We found an interesting theoretical result such that the Beltrami system {em without} natural boundary conditions (fixed boundary conditions) also provides a least-squares quasi-conformal map. This result elucidates why the Beltrami system always generates a parameterization with some conformality even if we use fixed boundary conditions.

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Copper-doped potassium sodium niobate CuO-(K0.48Na0.52)NbO3 (CuO-KNN) ceramics was fabricated via a hydrothermal method. An extra post- annealing process in air was adopted to analyze the relationship between mechanical quality factor and aging phenomenon. Quality factor (Qm) of CuO-KNN ceramics decreases to a small value after post-annealing and recovers gradually over several hours. This phenomenon is attributed to the rearrangement of oxygen vacancies in the domains. On the basis of such relationship, a new method of post-annealing in argon was proposed to enhance the Qm. Post-annealing in argon can significantly increase the Qm of CuO-KNN from 880 to approximately 1500 through increasing the amount of oxygen vacancies, which would impede movement of the domain structures. On the contrary, Qm decreases after post-annealing in oxygen atmosphere. High vibration velocity (0.9 m/s) was obtained, indicating that CuO-KNN is a promising material for high power applications.

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Human body communication (HBC) is a communication technique using human body and the environment surround body as a transmission medium. This technique which was introduced in 1995 has been a subject of attention from time to time. Most of previous studies about transmission characteristics of HBC used professional measurement instruments (such as oscilloscope, VNA or signal generator combining with ground isolators namely baluns, transformers) to measure. Those setups effect on an accurate because of creating a new parasitic paths between instruments. In this study, a battery-powered transmitter (Tx) and receiver (Rx) are created to measure channel gain. Received signal voltages are displayed on LCD integrated into Rx. Initially, our measurement setup has positions of transmitter (Tx) and receiver (Rx) as other studies to comparison with previous studies. On the other hand, we change the position of Rx to determine where are suitable for health monitoring applications. In reality, determining transmission characteristics of communication channel often mentions SNR at the receiver. Hence, we also measure noise power level at Rx by spectrum analyzer. Base on that, we recommend BER standard for health monitoring data transmission applications.

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