Improvement of piezoresistance properties of silicon carbide ceramics through co-doping of aluminum nitride and nitrogen

The piezoresistance coefficient was measured on co-doped silicon carbide ceramics. Evaluation samples of alpha-silicon carbide ceramics were first fabricated by glass capsule HIP method using powder mixture of silicon carbide and aluminum nitride with various ratios. The resultant aluminum nitride added silicon carbide ceramics were doped with nitrogen by changing the post-HIP nitrogen gas pressure. The lattice parameter increased with the amount of adding aluminum nitride indicating that the incorporated aluminum substituted smaller silicon atoms. After post-HIP treatment, lattice parameter then decreased with nitrogen gas pressure. The piezoresistive coefficient increased with the addition of aluminum nitride, it further increased with the nitrogen doping pressure

EXAMINATION OF A METHOD FOR DETECTION OF WALKING HEEL STRIKE AND TOE-OFF OVER A WIDE RANGE OF SPEEDS

This study examines a simple method to accurately detect heel strike (HS) and toe off (TO) timing over a wide range of walking speeds. HS was the moment when the heel passed a threshold in the downward direction. TO was the moment when the fifth metatarsal passed the threshold in the upward direction. The accuracies of these measurements were evaluated by comparing the moment acquired using a force platform. The root mean square (RMS) errors were 6.10 ms for HS and 15.6 ms for TO. These errors were smaller than those of previous studies. Furthermore, walking speed did not affect the detection precision in this method. Therefore, the detection method proposed in this study can detect HS and TO timing with better accuracy over a wide range of walking speed than previous methods

VARIANCE OF LOWER LIMB KINEMATICS DURING RUNNING ON TREADMILL

INTRODUCTION: It is empirically known that the less variance of motion is one of the reflectors of skillfulness in sports. There are some investigations which show that the small variance in movement indicates the high repeatability of that motion (Winter, 1983; Ferrario et al., 1995). However, very little information has been obtained about the variance of kinematics during long distance running. The purpose of this study was to clarify the effect of endurance running training and running speed on the intra-individual variance of lower limb kinematics during running in order to investigate the relationship between repeatability of motion and running skill in long distance running at various speeds

EXAMINATION OF AN APPLICABLE RANGE FOR A MARKERLESS MOTION CAPTURE SYSTEM IN GAIT ANALYSIS

This study aimed to verify the measurement accuracy of a markerless motion capture system using OpenPose in comparison with the conventional motion capture system using infrared cameras and to discuss an applicable range for the markerless motion capture system. We verified the accuracy of the system by calculating errors in the fundamental parameters of gait analysis. Those errors were 4.42 ± 2.02° in hip angle, 4.26 ± 2.54° in knee angle, and 5.93 ± 4.31° in ankle angle. The verification test revealed that this markerless motion capture system could be readily available, at least in the case of collecting 2D kinematics in the sagittal plane for gait motion

DETECTION OF FOOT CONTACT AND TOEIOFF USING KINEMATIC DATA FOR TREADMILL RUNNING OVER A WIDE RANGE OF SPEEDS

The purposes of this study were to propose a method for simply and accurately detecting the foot contact and toe-off events during treadmill running over a wide range of speeds and to examine the validity and accuracy of the method. Three patterns of foot-strike were distinguished from the foot kinematic data. The thresholds for foot contact and toe-off were determined inductively based on the minimum height of the heel or metatarsal for each foot-strike pattern with regard to running speed. The estimate for foot contact and toe off indicates that this method can apply over a wide range of speeds with high accuracy

THREE-DIMENSIONAL MOTION ANALYSIS OF THE "TENKAN9'-TECHNIQUE IN AIKIDO

Aikido is a Japanese martial art established by Morihei Ueshiba (1883-1969). A major characteristic is that there are neither competitions nor is there practice in form of competition. Generally, practice involves an instructor demonstrating a technique, after which it is practiced in pairs. The present study therefore sought to perform a three-dimensional analysis of the "Tenkan" a typical aikido technique, and to clarify the differences and factors related to the techniques for experts, intermediates, and beginners. We discussed the difference of deviation of the center of mass and evaluation of the ground reaction forces

RUNNING ECONOMY AND GASTROCNEMIUS MUSCLE LENGTH DURING RUNNING FOR KENYAN AND JAPANESE ELITE DISTANCE RUNNERS

The purpose of this study was to compare running economy and gastrocnemius muscle length during running for Kenyan and Japanese elite distance runners. Running economy was measured on the treadmill at 340 m/min while running motion was captured on the inside straight track at their racing speed. Gastrocnemius muscle length was estimated by the equation of Grieve et al. (1978) during the support phase at race speed running on the track. Kenyan runners showed higher running economy and smaller shortening length change of gastrocnemius during support phase than Japanese. These results suggest that shortening gastrocnemius during support phase of the running relates to running economy