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The purpose of this study is to examine changes in the kinetic parameters of the fingers caused by differences in ball velocity during overarm throwing. Six baseball players participated in the study, and the kinetics of the wrist and metacarpophalangeal (MP) joint were calculated using an inverse dynamics method. The results of Tukey's multiple comparison tests showed that the torque and work of the wrist increased with increasing ball velocity (p < .05), indicating that wrist torque and work contributed to the adjustment of ball velocity. Peak MP joint torque also increased with ball velocity (p < .05), although the work of the MP joint remained relatively constant. We conclude that MP joint torque and work contribute to the achievement of stable ball release rather than adjusting ball velocity. [ABSTRACT FROM AUTHOR]

This study had two objectives: (a) revealing the difference in finger segments between the conventional and finger models during aimed throwing and (b) examining the central nervous system's timing control between the wrist torque and finger torque. Participants were seven baseball players. Finger kinetics was calculated by an inverse dynamics method. In the conventional model, wrist flexion torque was smaller than that in the finger model because of the error in ball position approximation. The maximal correlation coefficient between the wrist torque and finger torque was high (r = .85 ± .10), and the time lag at maximal correlation coefficient was small (t = 0.36 ± 3.02 ms). The small timing delay between the wrist torque and finger torque greatly influenced ball trajectory. We conclude that, to stabilize release timing, the central nervous system synchronized the wrist torque and finger torque by feed-forward adjustments. [ABSTRACT FROM AUTHOR]

This study had two objectives: (a) revealing kinetic parameter differences at the fingers during a fastball and curveball, and (b) examining timing control between the wrist and finger torques. The participants were eight baseball pitchers. The kinetics of the wrist and fingers were calculated using an inverse dynamics method. The peak torque and work of finger adduction during the curveball was significantly larger than that during the fastball. During the fastball pitch, the maximal correlation coefficient between the wrist flexion torque and finger flexion torque was very high (r = 0.94 ± 0.05). The reasons for this result are twofold: (a) the extrinsic finger muscles cross the wrist (biarticular muscle) and (b) the wrist flexion torque during the fastball pitch acts in the direction of acceleration of the ball. During the curveball pitch, we found two typical types of wrist and finger torque control. Furthermore, the two pitchers exerted large wrist extension and radial torque, and finger adduction torque. Although the other six pitchers hardly exerted these torques, they exerted wrist flexion torque predominantly. It was considered that the six pitchers selected wrist flexion torque as the control for the fastball and curveball pitch to confuse the batter. [ABSTRACT FROM AUTHOR]

A section of the time-temperature-transformation (TTT) curve has been measured in the millisecond regime to describe the A1 to L10 transformation of 10 nm FePt thin films. Short time annealing was accomplished using a pulsed neodymium-doped yttrium aluminum garnet laser operating at a wavelength of 1064 nm. The temperature-time profile of the films was measured using an optical pyrometer and a platinum thin film resistor and it was numerically modeled. Effective thermal pulse widths were determined from the time dependence of the atomic diffusion coefficient calculated from the measured temperature profile. The measured TTT diagram involving average order parameter is consistent with theoretical predictions of TTT diagrams involving ordered volume fraction and shows that partial ordering can be obtained with a single effective thermal pulse as short as 1.1 ms. [ABSTRACT FROM AUTHOR]

A series of ≈12 nm thick FePt thin films deposited onto glass substrates have been annealed with multiple 1064 nm wavelength laser pulses. The fluence was varied using pulse widths of 10.0, 5.0, and 2.5 ms. The peak temperature for each individual pulse was kept near 700 °C. The A1 to L10 phase transformation was confirmed by x-ray diffraction. A single pulse was not sufficient to obtain a fully ordered state. A maximum order parameter of 0.89 and coercivity of 10.6 kOe was obtained after 5×10 ms pulses. This particular annealed film showed the greatest amount of grain growth with a mean size of 55.1 nm. This grain size is 20% smaller than that of a furnace annealed sample which was annealed for 60 s and yielded an approximately equivalent order parameter. Similar order parameters, grain sizes, and coercivity values were observed for films that had equivalent total annealing times regardless of pulse widths. [ABSTRACT FROM AUTHOR]

A series of FePt thin films deposited onto glass substrates are annealed with multiple 1064 nm wavelength laser pulses. Similar order parameters, grain sizes and coercivity values are observed for films that have equivalent total annealing times regardless of pulse widths.