During the course of the experimental work included in this investigation, it was found that certain adjustments and conditions had a major effect on the performance of the tested engine, whereas certain others had a very minor effect. In order of decreasing importance, the conditions which affected the engine's operation were: (1) restriction of the air supply to the carburetor; (2) restriction of the flow of exhaust products from the engine; (3) a change in the carburetor float level; (4) a variation of the ignition timing within five degrees of that recommended; (5) the use of spark plugs which had been run a larger mileage than that recommended by the manufacturer; and (6) a change of the distributor breaker point gap within 0.007" limits of that recommended by the manufacturer. Restricting the air supply to the engine had a very large adverse effect on the economy of the engine, and a smaller effect on the power. Restriction of the exhaust line had approximately the same effect on the power and economy of the engine. Raising the carburetor float level decreased economy characteristics markedly, and power characteristics to a much smaller extent. Lowering the carburetor float level increased both the power and economy of the engine. A five degree advance in the ignition timing resulted in a slight increase in power and economy in the low speed range, this increase being at the expense of violent detonation. The performance in the high speed range was adversely affected. Retarding the spark timing five degrees had a detrimental effect on both power and economy, although this effect was comparatively small. The use of spark plugs beyond the recommended mileage limit showed a decrease in power and economy when this effect was not counteracted by the increase in the size of the gap due to normal usage. Spark plugs which had been cleaned at frequent intervals showed up much better on test than did those which had not. A change in the spacing of the distributor breaker points through a 0.014” range showed an effect of less than three percent when the natural effect of this change on the ignition timing was corrected. Things such as air cleaner and muffler restrictions, changes in the carburetor float level, and fouled spark plugs caused enough effect on the engine's performance to indicate the advisability of checking these things often. Other conditions which would normally be checked in a minor engine tune-up do not have an appreciable effect on the performance of the engine, providing that their effect is not sufficient to make the engine miss. / M.S.

published_or_final_version / Business Administration / Master / Master of Business Administration

Most existing structural health monitoring (SHM) techniques are based on measured acceleration data. Such practice, however, is highly expensive to operate, mainly due to cumbersome, time-consuming and expensive installation of sensors and their data acquisition systems. As an emerging noncontact method, the vision-based displacement sensor systems have attracted significant research interests and offered a promising alternative to the conventional sensors for SHM. However, most existing vision-based sensors require physical access to the structure to install a predesigned target panel, which has a higher contrast and thus is easier to track. Besides, most studies are carried out in controlled laboratory environments. The accuracy and robustness of vision sensors in the outdoor field conditions have not been fully investigated. It is also noted that current researches are mainly focusing on the measurement performance evaluation of vision sensors, without discussing the use of the measured displacement data for SHM. This dissertation develops a high-precision vision sensor system for remote and real-time measurement of multipoint structural displacements by tracking natural targets on structural surfaces. Two sets of software packages are developed respectively based on two advanced template matching algorithms (i.e., the upsampled cross correlation and the orientation code matching) incorporated with different subpixel techniques. Comprehensive experiments, including laboratory shaking table tests and field bridge tests, are carried out to evaluate its performance. Satisfactory agreements are observed between the displacements measured by the proposed vision sensor and those measured by high-performance reference displacement sensors. Moreover, this study examines the robustness of the vision sensor against ill environmental conditions such as dim light, background image disturbance and partial template occlusion. This dissertation further explores the potentials of the vision sensor for fast and inexpensive SHM applications, by demonstrating the usefulness of the displacement data for experimental modal analysis, finite element (FE) model updating, damage detection, etc. For a three-story frame structure, the modal analysis shows that the obtained natural frequencies and mode shapes from displacement measurements by using one camera match well with those by using four accelerometers. In fact, the vision sensor can achieve smoother mode shapes which would make damage localization more accurate, while the resolution of mode shapes from accelerometers is limited by the sensor number. This has been demonstrated from the damage detection result of beam structures based on the mode shape curvature (MSC) index. To address the needs for monitoring aging railway and highway bridges, coupled train-track-bridge and vehicle-bridge FE models are firstly developed to study the dynamic interactions between bridges and moving trains/vehicles. Subsequently, a time-domain model updating approach for railway bridges is proposed based on the in-situ measurement of the bridges’ dynamic displacement histories by the proposed vision sensor. This dissertation further proposes a bridge damage detection procedure that utilizes vehicle-induced displacement response and the MSC index without requiring prior knowledge about the traffic excitation.

published_or_final_version / Public Administration / Master / Master of Public Administration

No description available.

"During the past twenty-five years the writer has taught in various types of buildings, ranging from army barracks to buildings, which, when built, represented the very best in modern school planning. Out of this experience comes a knowledge of the effect the physical plant actually has as a determining factor in the teacher's ability to give proper instruction. A teacher may do his best with the equipment and facilities offered without accomplishing the same satisfactory results that could be possible under better conditions. The realization that the value of the physical plant is important has created a desire to make a study of the modern trends in school architecture and planning. From personal experience and research it is proposed that in this article ways and means be suggested whereby existing facilities might be improved at Sealey Memorial School"--Introduction. / "July 15, 1949." / Typescript. / "Submitted to the Graduate Council of Florida State University in partial fulfillment of the requirements for the degree of Master of Arts under Plan II." / Advisor: R. L. Eyman, Professor Directing paper. / Includes bibliographical references (leaves 63-64).

A model which helps system designers to jointly evaluate a repairable equipment population system and its associated logistics support subsystem is developed. The modeled system consists of a deployed population of repairable equipment and a logistics support subsystem consisting of repair channels and an inventory of consumable components. In the system, a population of identical repairable equipment is procured and deployed to meet a known and constant demand. As the equipment fails, it is repaired and returned to service. Equipment repair generates secondary demands for consumable components and spares. Backorders within the inventory support subsystem add to the time failed equipment is not in service. The model returns optimal values for the number of equipment units to deploy, the number of maintenance channels, the retirement age of deployed units, the procurement level, and the procurement quantity. These values are optimal in that they minimize the expected equivalent annual life-cycle cost of the system. The best system design may then be selected from among candidate designs on the basis of minimum life-cycle cost. Previous attempts at integrated logistic system evaluation have led to suboptimal results because evaluation of the repairable equipment population system was disconnected from the evaluation of the inventory subsystem. Where inventory backorders are allowed, there are tradeoffs between system-level shortage costs and the cost of procuring and holding inventory.The backordered consumable components contribute to equipment repair times by increasing the time spent in repair. Furthermore, the procurement of additional repairable equipment to offset shortage penalties may result in increased logistics support costs which must be accounted for when evaluating system design alternatives. This thesis presents a model for a repairable equipment population system with its associated logistics support subsystem. The evaluation function is developed along with assumptions and definitions of the cost elements. A numerical example which illustrates some basic aspects of the model is given. Finally, an optimization routine is presented which returns an optimal set of system design variables for a given set of design and source dependent parameters in the face of design and source independent parameters. / Master of Science

The problems associated with increased heavy grain truck traffic in rural regions were investigated. Both the short-run incremental costs of accelerated pavement replacement and the long-run incremental costs of upgrading low-volume highways were considered. A set of demand and traffic models was formulated which projects the annual flow of grain from each production zone in an impact region to each elevator, allocates the flows among truck-types, computes the annual trips, gross vehicle weights and axle weights, and assigns the truck trips to the highway network. A set of highway models was also formulated which computes the equivalent single axle loads for each highway section in an impact region and estimates the incremental costs associated with subterminal traffic. The impacts of a newly-formed subterminal-satellite elevator system in rural North Dakota were investigated. The results of the case study indicate that rural collector highways are likely to experience substantial localized impacts from subterminal development but the effects on principal arterials may be minimal. Altogether, $1.14 million in short-run costs and $8.41 million in long-run costs were projected for the impact region. However, the case study roads represent less than 2 percent of the rural arterial and collector highway mileage in the state. If the case-study network represents a microcosm of rural North Dakota, then the statewide short-run and long-run incremental costs may be in the vicinity of $57 million and $420 million respectively. However, regional variations within the state may result in either higher or lower costs for a given elevator system than those projected in the case study. / Ph. D.

M. Tech. Business Administration / The research reviews how the implementation of total productive maintenance (TPM), as a maintenance strategy, can be adopted at DCD Wind Towers (Pty) Ltd., a wind tower manufacturing company in South Africa. It also focuses on maintenance management programmes, identifies obstacles, barriers and challenges to the implementation of maintenance management programmes.

Rural road maintenance has received little or no attention in Zambia for a long time, resulting in an adverse impact on the economy. Meanwhile Road Authorities have continued to use traditional capital-intensive periodic and routine maintenance at the expense of scarce foreign exchange. The system has not performed well, hence the current state of roads. Labour-based methods for routine maintenance under the Lengthmen System used in Kenya, Lesotho and other developing countries in the Sub-Saharan Africa have proved to be technically and economically viable. In this report the author examines the desirability of using the Labour-Based Lengthmen System as an alternative to the existing capital -intensive methods in Zambia. This is done through rev iewing rural road maintenance in Zambia and then carrying out a comparative analysis of the same bctween Zambia, Kenya and Lesotho The comparative analysis shows that Zambia is not performing well when compared to Kenya and Lesotho. Meanwhile, the Lengthmen System is more desirable compared to other methods under the current economic conditions. Recommendations, based on the comparative analysis, have been given to improve rural road maintenance in Zambia. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.