Browsing by Subject "kinematics"
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Item An examination of the impact of introducing greater contextual interference during practice on learning to golf putt(Texas A&M University, 2005-02-17) Hwang, Gyu-YoungThe skill of putting in golf contributes approximately 40 percent to one?s total score making it an important skill to master in golf. One of the critical means of improving putting skill is through practice. The purpose of this study was to: (a) investigate if different practice schedules with different degrees of contextual interference (CI) influenced the participants? immediate and long-term putting performance, (b) examine if performance changes were associated with concomitant changes in specific kinematic parameters, and (c) assess the cognitions of the participants during various stages of the practice of the putting skill. Twenty-four undergraduate students were randomly assigned to either a blocked or random practice schedule. On Day One each participant practiced putting to three targets (4 ft, 8 ft, and 12 ft distance) for a total of 108 trials (36 trials to each target). On Day Two 30 trials of retention (10 trials to each target) and 10 transfer trials (10 ft distance) were performed. To obtain a kinematic description of the putting action, an OPTOTRAKTM 3020 camera system recorded the 3D movement of the putter. Participants? cognitions were analyzed from stimulated recall interview data. Random practice participants exhibited poorer putting performance during acquisition compared to their blocked practice counterparts but showed superior performance in retention and transfer tests. While the blocked practice participants had significantly lower variability in the amplitude in the x-dimension for backswing, impact velocity, and putter position at impact (z-dimension) during practice, the random practice participants showed significantly lower variability in the amplitude of the x-dimension for the backswing and downswing, impact velocity, and putter position at impact during the retention and transfer phases. Content analysis of interview data yielded three emergent categories: participant focus, self-evaluation of performance, and benefits of practice. The participants provided evidence of active thought processes during the putting task while receiving little instruction. The blocked group focused more on accuracy while the random group was more focused on judging distance. The lack of recognition about the z-dimension has potential implications for how instruction and feedback might be employed during the learning process.Item Kinematic and Mechanical Reconstruction of Walker Ridge Structures, Deepwater Gulf of Mexico(2011-02-22) Majekodunmi, Oluwatosin EniolaRecent high-resolution seismic imaging has allowed detailed reconstruction of the relationship between fold development and crestal faulting of the Chinook and Cascade folds in the deepwater Gulf of Mexico. Using 3-D seismic and biostratigraphic data, we have found that (1) short wavelength (~2300m), small amplitude folds (~540m) within the upper Cretaceous and upper Jurassic stratigraphic sequences took place no later than the late Jurassic, (2) large wavelength and amplitude fold growth, starting in the early Cretaceous, was produced by salt withdrawal, and (3) periods of increased sedimentation, fold growth, and fault slip occurred during the middle Miocene and late Miocene. Although the dominant stage of long wavelength, large amplitude fold growth started around early Cretaceous, the development of the Cascade and Chinook structures was continuous, punctuated by episodes of accelerated growth during the middle Miocene at rates of 337 and 235 m/Ma in the Cascade and 203 and 230 m/Ma in the Chinook. A later event of accelerated growth occurred during the late Miocene at rates of 1038 m/Ma in the Cascade and 1189 m/Ma in the Chinook. Accompanying fold growth was sedimentation, which was highest at 1949 m/Ma in the Cascade and 2585 m/Ma in the Chinook. Although limb tilt rates varied through fold growth, the highest rates also occurred during the middle Miocene at 0.330 and 0.196 degree/Ma for the Cascade and Chinook, respectively with the development of crestal faults at maximum slip rates of 88 and 90 m/Ma.Item Kinematics measurements of regular, irregular, and rogue waves by PIV/LDV(Texas A&M University, 2007-04-25) Choi, Hae-JinA comprehensive experimental study was conducted to produce benchmark wave kinematics data for five different regular waves and the maxima of four different irregular wave trains. Two of the irregular waves generated are in the category of rogue waves. A series of experiments were conducted in a 2-D wave tank at Texas A&M University to measure wave velocities and accelerations using LDV and PIV systems. The wave crests of regular and rogue waves are the focus of this study. With the measured wave velocity field, the wave accelerations were computed using a centered finite difference scheme. Both local and convective components of the total accelerations are obtained from experimental data. Also, the nonlinear wave forces on a truncated slender cylinder are computed by applying the obtained wave kinematics to the Morison equation. The force results based on measured wave kinematics are compared with those based on the kinematics of linear extrapolation, Wheeler stretching, and modified stretching. The Wheeler stretching method generally underestimates the actual wave kinematics. The linear extrapolation method is very sensitive to the cutoff frequency of the wave spectrum. The modified stretching method tends to predict the maximum value of wave kinematics above the still water level (SWL) well except for the convective acceleration. The magnitude of convective acceleration in the regular waves was negligibly small, whereas the magnitudes of horizontal and vertical convective accelerations in the rogue wave were increased rapidly above the SWL.