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The recent development of North Sea oil has seen the construction of massive structures founded in the seabed of the North Sea. Inadequacies in existing site investigation techniques employed for the design of the foundations of these structures have shown that a need exists for a device to permit an accurate and rapid assessment of the soil conditions existing below the seabed. This thesis considers the application of the vibrohammer, a machine capable of driving piles tubes or rods rapidly into the ground under a self-adjusting combination of vibration and impact, as the driving mechanism both for a coring device and a dynamic penetrometer. In so doing it presents the historical development of the vibrohammer from its introduction in the U.S.S.R. circa 1940, together with the parallel development, also in the U.S.S.R., of theoretical treatments of vibro-impact dynamics. An experimental investigation is carried out at both model and full-scale level and confirms that a vibrohammer is capable of self-adjusting the magnitude of the impacts it generates with increasing soil resistance. The capacity of a vibrohammer to produce rapid penetration rates does not arise from a potential to produce large impacts but from the ability to produce an optimum combination of vibration and impact. Optimum machine parameters at which the self-adjustment results in maximum depths of penetration are identified and explained both from the experimental work and a computer simulation of the vibro-hammering process. A possible mechanism by which this self-adjustment occurs is proposed. The application of a vibrohammer as the driving mechanism for a dynamic penetrometer requires the selection of machine parameters different from those which result in maximum penetration depths. In order to maximise the ratio of the measured dynamic soil resistance to the corresponding static soil resistance it is necessary to operate a vibrohammer in a predominantly impact mode. The development of a mechanical adaptor unit by which existing pure vibratory coring devices may be modified to operate as a vibrohammer is presented and discussed in the light of preliminary field test results.

In this thesis, the dynamic responses of harmonic drive (H.D.) systems under different operating conditions are investigated. The numerical simulation and the experimental measurements of harmonic drive systems are included in this thesis. The effects of flexspline of harmonic drive, i.e., the torsional stiffness and the damping ratio on the response of corresponding system are studied .Lagrange¡¦s equation is employed to derive the equation of motion of the system. The system equation with a nonlinear torsional stiffness is solved by using the 6th order Runge-Kutta method. Comparison between numerical simulation results and experimental measured data indicate that the proposed harmonic drive model is accurate and feasible for simulating the dynamic response of a harmonic drive system.

ABSTRACT The wheelchair is an auxiliary tool for people who have defective legs. In the viewpoint of mechanical efficiency, the typical manual wheelchair does not provide optimal efficiency, and the wheelchair occupant can¡¦t travel easier and faster for longer distances. The regular, standard manual wheelchair is only suitable for residential environment and short-distance movement, and it¡¦s unsuitable for outdoor long-distance movement. The purpose of this study is to design a new-pattern manual wheelchair for outdoor recreation and long-distance movement, so that the users can expand their living space beyond the residential areas. In order to enhance the efficiency of propulsion for manual wheelchairs, the new-pattern wheelchair has a new type of dive system. In this study , we will design a detachable drive mechanism for manual wheelchairs. The new-pattern wheelchair has two kinds of different propulsive modes, the wheelchair occupant can depend on his requirement to decide what propulsive mode he needs. At last, we hope that we can promote the performance of wheelchair effectively by means of study and design.,and that is the principal objective for this study.

Abstract The harmonic drive mechanism has been used wildly in industrial robots. High reduction ratio, few components, and quiet torque transfer are the advantages of this device. In this thesis, the dynamic characteristic of an integrated DC motor and harmonic driver system is investigated. The dynamic equations of the harmonic drive systems are derived by applying Lagrange¡¦s equation. Two different harmonic driver designs, i.e. a cup-type with two teeth difference and a circular type with four teeth difference are used in the analysis. The system responses are simulated by employing the sixth order Runge-Kutta method. Comparison between numerical simulation results and experimental results, it indicates that the proposed model is feasible and accurate for simulating the dynamic response of an electro-mechanical integrated harmonic drive system.

The purpose of this study was to establish the pre-shot routine usage pattern of amateur golfers using the driver and to correlate that pattern to their effectiveness off the tee. Forty eight participants including 42 males and 6 females participated in this study. The mean age of the total population was 34.6+12.4 and ranged from 20 to 60 years of age. The participants were asked to answer the pre-shot routine questionnaire. The participants completed the 5 section questionnaire consisting of subject demographics, playing experience, playing ability, driving ability from the tee box, and pre-shot routine on the tee. The participants indicated that slicing was the biggest problem. The results show that 37.4% of the participants sliced the ball 50% of the time or more. Of those individuals 4.2% sliced the ball 100% of the time. Hooking the ball was less of a problem with only 18.8% hooking 50% or more of the time. Hitting the ball fat (taking too much turf) and hitting the ball too thin (no turf taken) gave similar results, with 16.7% of the subjects hitting fat shots 50% of the time or more, and 12.5% of them hitting thin shots 50% of the time or more. The biggest difference being that none of the respondents hit fat or thin shot 100% of the time. A majority of the participants (66.6%) have a great deal of confidence that they would hit a good tee shot from an open fairway. However, that confidence level drops to only 27.1% when the fairway is tree lined and only 4.2% of our participants feel confidence 100% of the time. If the tee shot has to be made over water only 35.5% of the respondents feel confidence off the tee with 18.8% in the 100% category. The last factor we asked them to rate was whether or not they had confidence if someone was playing with them. Only 35.4% of the respondents felt confident 80% of the time or more, with only 12.5% being confident all of the time. Participants using the white, blue and gold tee box stand behind the ball and pick a target but the participants using the red tee box did not at all. It is interesting to note that the players with the best handicap and lowest average score use this technique 100% of the time, whereas less than half of the white and blue tee box players use it. It shows that standing behind the ball and picking a target may be more useful for the golfers than just lining up as they address the ball. Other elements like practice swing, mental rehearsal, and movement do not seem to have much correlation to the players ability in that they showed a great deal of variation. We can say that these elements are affected by personal habit or routine more than their playing ability. Although the forward push is highly recommended by professional players and instructors very few participants in this study used this technique. The results of this study show that a consistent pre-shot routine does not help amateur golfers. The inconsistency of the pre-shot routine these subjects used makes it impossible to make recommendations concerning the effectiveness of a pre-shot routine. What the data does do is provide the framework for additional research in which subjects are required to use the same pre-shot routine that is designed by professionals. / School of Physical Education, Sport, and Exercise Science

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This is a collection of poems.

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