Abstract The goals of this paper are twofold: selection of pseudo-boundaries for sources nodes in the method of fundamental solutions (MFS), and comparisons of the MFS, the method of particular solutions (MPS) and the MFS-QR of Antunes. To pursue better pseudo-boundaries, we provide new estimates of the condition number (Cond) by the MFS for arbitrary pseudo-boundaries, and propose a new sensitivity index of stability via accuracy. Numerical experiments and comparisons are carried out to verify the analysis made. For five-pedal-flower-like domains, numerical comparisons are made by the sensitivity index. Circular pseudo-boundaries are optimal for highly smooth solutions, but the pseudo-boundaries near the domain boundary may be better for singular solutions. In this paper the gap has been shortened between theoretical analysis and numerical computation of the MFS, to provide some guidance for users. This is the first goal of this paper. The second goal is to compare the MFS, the MPS and the MFS-QR. Characteristics of the MFS-QR are explored. The new basis functions of the MFS-QR are the very particular solutions (PS), and the MFS-QR may be regarded as a special MPS. The MFS-QR is not a variant of the MFS but a variant of the MPS. The MFS-QR also plays a role in bridging from the MFS to the MPS. Both the MFS and the MPS can also be recognized as twins via the MFS-QR in the Trefftz family. The comparisons in this paper are more comprehensive.
An investigation of outgassing effects on boundary-layer transition was carried out. This joint computational–experimental work mimicked heat-shield pyrolysis outgassing in atmospheric reentry cond...
Ikeda, N and Ryushi, T. Effects of 6-week static stretching of knee extensors on flexibility, muscle strength, jump performance, and muscle endurance. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to evaluate the changes in flexibility and muscular performance after stretching training for 6 weeks. Twelve healthy young men were assigned to a stretching group and 13 to a control group. The participants of the stretching group performed static stretching of knee extensors for 6 weeks. Knee flexion range of motion (KFROM), leg extension strength, rate of force development (RFD) in leg extension, jump performance (squat and countermovement jump height, and index of rebound jump), and strength decrement index of 50 repetitions of isokinetic knee extension (muscle endurance) were measured before and after the interventions. In the stretching group, KFROM significantly increased from 145.2 ± 17.3 to 158.7 ± 6.3° (p < 0.05), whereas RFD significantly improved from 10,173 ± 2,401 to 11,883 ± 2,494 N·s (p < 0.05). By contrast, leg extension strength and jump performance of each jump type did not improve significantly. Furthermore, muscle endurance decreased significantly. All variables remained unchanged in the control group. In conclusion, 6 weeks of stretching training of knee extensors improved KFROM and RFD in leg extension, but not leg extension strength and jump performance; moreover, muscle endurance decreased. These findings indicate that this stretching training protocol can be used by athletes in sports who require high flexibility and those who require high-power exertion.