No abstract

No abstract

Abstract. Motion capture system has recently being brought to light and drawn much attention in many fields of research, especially in biomechanics. Marker-based motion capture systems have been used as the main tool in capturing motion for years. Marker-based motion capture systems are very pricey, lab-based and beyond reach of many researchers, hence it cannot be applied to ubiquitous applications. The game however has changed with the introduction of depth camera technology, a markerless yet affordable motion capture system. By means of this system, motion capture has been promoted as more portable application and does not require substantial time in setting up the system. Limitation in terms of nodal coverage of single depth camera has widely accepted but the performance of dual depth camera system is still doubtful since it is expected to improve the coverage issue but at the same time has bigger issues on data merging and accuracy. This work appraises the accuracy performance of dual depth camera motion capture system specifically for athletes' running biomechanics analysis. Kinect sensors were selected to capture motions of an athlete simultaneously in three-dimension, and fused the recorded data into an analysable data. Running was chosen as the biomechanics motion and interpreted in the form of angle-time, angleangle and continuous relative phase plot. The linear and angular kinematics were analysed and represented graphically. Quantitative interpretations of the result allowed the deep insight of the movement and joint coordination of the athlete. The result showed that the root-mean-square error of the Kinect sensor measurement to exact measurement data and rigid transformation were 0.0045 and 0.0077291 respectively. The velocity and acceleration of the subject were determined to be 3.3479 ms -1 and −4.1444 ms -2 . The result showed that the dual Kinect camera motion capture system was feasible to perform athletes' biomechanics analysis.

It is widely known that significant rejection percentage of substrates in the hard disk manufacturing industry is due to the stain appeared during drying of cleaning solution after platting process. Comparison of the characteristics and the causes of these stains suggested that the study of coffee ring effect (CRE) and droplets analysis are needed before any further analysis is carried out. In this review on CRE and droplets, both numerical and experimental works were critically analyzed. Previous studies have highlighted that the drying process of the water droplets are affected by the properties of the water droplets, substrate and temperature. Manipulation of Constant Contact Angle, Constant Contact Radius, advanced contact angle and receding contact angle by varying the arrangement of the substrates and the position of the drying equipment is required to attain the optimum setup to eliminate CRE. Furthermore, manipulation of the temperature of the substrates can enhance the drying process of the droplets before the formation of CRE but the process must not change the properties of the substrates. CRE formation also depends on the properties of the substrates and water droplets. Changing the chemical properties substrates are not advisable to eliminate CRE due to its complex design of the substrates for data storing. All the numerical tests have to be performed according to correct procedures to ensure accurate and acceptance by the industries. Verified and validated results from the evaluation will help to accurately predict the real consequences for further optimization. Knowing that the formation of CRE is caused by the evaporating of the water droplets, we need to find ways to eliminate the formation of water droplets before the heating process, in order to eliminate CRE.

No abstract