Data collected with a three-component laser Doppler anemometer system is used to investigate velocity bias. The data is collected in the viscous layer of a fully developed turbulent open water flow at a Reynolds number of 14,766 based on the flow depth. The data collected at a relatively low data rate is analyzed using different correction methods including: straight forward arithmetical averaging, inverse velocity and transit time weighting. The streamwise mean velocity components, the RMS values and the kinematic Reynolds stress are computed using the various weighting methods and are compared to a three-component inverse velocity bias correction model which is taken to represent the "true" values. The three-component inverse velocity bias correction results are in general accordance with the expected behavior in open channel flow and are comparable to the results reported by other researchers employing different experimental techniques. The results of this study show that the bias is sensitive to the correction method used and the theory that the mean streamwise velocity error (without correction) is proportional to the square of the turbulence intensity is confirmed experimentally. Averaging the data without correcting it produced the largest bias while the results from the different inverse velocity techniques were approximately the same although the level of the bias varied with the turbulence variable that was analyzed. As reported in the literature, the transit time weighting method requires accurate determination of the residence time. The relatively poor performance of the transit time method in the present comparison is attributed to the poor accuracy in the measurement of the residence time. / Master of Science

Personal communications has produced a demand for low-Earth orbit satellite (LEOSAT) implementation. A proposed LEOSAT link at VHF would provide paging and radio-location services to subscribers in automobiles. Link performance has traditionally been determined by thermal background noise produced internally as well as externally to the radio receiver. Most recently, however, man-made noise has become the dominant source of link interference at VHF frequencies and below. This thesis examines the statistical behavior of man-made noise through a series of in situ measurements, and implements a statistical-physical mathematical model to provide bit-error rate (BER) predictions for system designers. The model is also applied in an attempt to scale the statistics for bandwidths other than the noise measurement receiver. Man-made noise is inherently impulsive, due to switching processes in the AC power distribution system. Gaussian noise models are therefore inappropriate for the description of man-made noise statistics. A model by Middleton was developed around the Poisson mechanism to accurately predict the amplitude probability distribution (APD) of the received noise. Unlike empirical models, the constants employed by the Middleton model posses physical significance. / Master of Science

This thesis is concerned with the effects of earthquakes on partially-filled water tanks. The analysis is applicable to rectangular water tanks, which have received little attention to date. The analysis is relatively involved and includes the derivation of the equations of motion for the vibration of the whole of tank by means of substructure synthesis, a stochastic analysis relating the random ground motion caused by earthquakes to the random vibration of the tank, a stochastic characterization of the fluid pressure and computation of the probability of failure of the tank. / Master of Science

An analytical treatment of the fatigue performance of a cam-roller followler system as influenced by residual stresses induced by grinding, is developed. An approach based on an extended Hertzian analysis is used to determine the 3-D contact stress fields, which are then combined by elastic superposition with the residual stress fields. These residual stresses were measured previously by the x-ray diffraction technique and represent a range of grinding protocols from mild to abusive. The maximum cyclic component, generally occurring subsurface, is then identified in terms of an effective stress amplitude and mean which are used with a fatigue damage model to predict fatigue crack initiation. Results, pending experimental confirmation, appear reasonable and provide a useful basis for optimizing cam performance in terms of manufacturing and design parameters. / Master of Science

No Virginian was more dedicated to the Confederate cause than Stapleton Crutchfield. Born into a prominent and wealthy family, Crutchfield enjoyed and embraced the southern aristocratic lifestyle. He was a Virginian first and a United States citizen second. When Crutchfield was sixteen, he enrolled at the Virginia Military Institute. The young man had been enamored with the military tradition of his family and the extreme militancy of the South. Graduating at the top of his class in 1855, Crutchfield stayed on at the Institute as a mathematics professor. As Virginia prepared for war in 1861, Crutchfield resigned from his post and joined the Confederate army as an officer. The former mathematician was anxious for a fight. He believed that Virginia and the southern lifestyle was endanger of being destroyed by the North. Crutchfield's military training and family connections helped him receive appointment to the rank of major. In 1862, Gen. Thomas Jackson appointed Crutchfield to chief of artillery of his division. While Crutchfield had received training in artillery at the Institute l the instruction he received would not prepare him for the Civil War. New technology and the massive size of the armies had drastically changed the role of artillery in battle. His experience would come through trial and error on the battlefield. As Jackson's successes catapulted him to the top of the Confederate army's hierarchy, Crutchfield assumed additional commands and responsibilities. He became one of the few men to command artillery corps in the Civil War. During his tenure as artillery chief, the "long arm" of the Army of Northern Virginia experienced its largest growth. Furthermore, it is when Lee's army had its greatest successes on the battlefield. Yet, Stapleton Crutchfield has been overlooked by Civil War historians. They have failed to investigate the complexities of being artillery chief during the army's greatest period of growth and success. Crutchfield played an invaluable role in the shaping of the Army of Northern Virginia's artillery. His actions influenced the artillery corps even after his wound forced him to retire from his post. / Master of Arts

Eye movements are thought to be representative of an observer's attention. Researchers have used eye movements to gain insight to the mental processes of observers while they view pictorial stimuli. The present research was conducted to determine if subjective reports of attention are representative of eye movements, and if there are differences in the subjective reports between novice picture-takers and expert judges. Two studies were performed to answer these questions. The Image Evaluation study employed 24 subjects to examine 20 soft-copy photographic images. The 24 subjects were divided into four nested combinations: Protocol and Group. Two types of protocol were used, concurrent and retrospective, and two expertise groups were used, novice picture-takers and expert judges. The subjects viewed and rated the quality of each image. Subjective reports of attention were then collected by using a mouse to click on the features that influenced the quality rating. The second study, the Eye Tracker study, used six subjects, all novices, to examine and rate each image while eye movements were recorded, after which their subjective reports of attention were collected. Measures of time, frequency, location, and the quality rating were collected for each subject on all images. These measures were then subjected to parametric and nonparametric statistical tests. The two groups, expert and novice, displayed a difference only when rating the quality of the image. The two protocols were not statistically different for any dependent measure, although for this task a retrospective protocol is recommended. The subjective reports of attention did not represent the eye movements. Questions concerning the method employed to collect the reports are addressed. / Master of Science

The concept of quality management is operationalized in an organization through a Quality Management System (QMS) - a complex, coordinated set of activities and behaviors aimed at improving the quality of an organization's processes, goods, and services. Like all systems, a QMS must be planned, monitored, improved, and maintained over time to function at its best. For this, measurement is key. The standard of quality management performance developed by Triantis, et. al. (1991b) is the quality management system definition used in this thesis. The thesis subsequently makes three contributions. First, it provides a methodology for defining generic measures of QMS performance and evolution, and implements this methodology in creating more than 200 prototype measures for 10 out off the 37 component "modules" of a QMS. Second, a methodology is presented for developing a tool to collect the very data called for by the measures. This methodology is implemented and a prototype questionnaire developed to collect measurement data for the Vendor/Contractor Relations (VCR)module of a QMS. Third, given the vast amount of data collected with the various questionnaires that needs to be manipulated in order to manage the QMS, it is important to be able to use automation. Therefore, it becomes necessary to logically organize the data. The entity-relationship (E/R) modeling technique is one approach that can be used to achieve this objective. This E/R approach is used to logically organize data that is generated by the questionnaire for the VCR module. In so doing, one can assess the potential viability of this data modeling approach and begin laying the foundation for a database that will support the measurement requirements of a QMS. / Master of Science

This study concerns the effect of column temperature on selectivity in gas chromatography (GC). Reversal of peak elution order at different temperatures is observed when selectivity is sufficiently changed by changing the temperature. A study of homologous functional groups and the elution order of a test mixture was made at several temperatures, by keeping constant operating chromatographic parameters such as column head pressure, split ratio, sample concentration, injector and detector temperature. The homologous series studied were esters, carboxylic acids, ketones and alkanes. The stationary phases used were Carbowax (Supelcowax 10), and 5% diphenyl and 95% dimethyl silicone ( HP Ultra 2). The identification of each compound was confirmed by two methods : comparing retention times, and spiking the sample. The results of an investigation for accurately determining the dead time is also presented. The experimental results of using 10% methane in helium and the results of a theoretical model based on Poiseuille's equation were studied and compared. It is concluded that dead time calculations are a major source of error for the calculations in this work. In addition, a derived thermodynamic equation based on the Van't Hoff equation was obtained and used to calculate the molar enthalpy and entropy of compounds over a range of temperatures. The experimental thermodynamic values were compared with the theoretical values obtained from the Clausius- Clapeyron equation. From the data obtained, a graph of In k' (retention factor) versus 1/ temperature for a homologous series, known as a Van't Hoff plot, predicts a reversal of elution order where an intersection of two lines occur. Selectivity of the stationary phase has changed solely due to temperature effects. This can only occur when different solute/solvent interactions are present. This work is an attempt to predict when peak inversion should occur based on the Van Hoff's plot. Experimental result are presented that confirm the prediction. / Master of Science

The behavior of composite steel joists with various degrees of shear connection is investigated. The results of eight full-size composite joist tests, conducted as a portion of the study, are presented. Joist spans range from 24 ft. to 30 ft. and depths from 8 in. to 18 in. Six types of mechanical connectors provide horizontal shear transfer capacity. Steel deck supported slabs, from 3 in. to 4 in. thick, are used for all tests. The results of the experiments are used to evaluate the flexural strength and associated failure modes of partially composite and fully composite joists. The results of each test are compared to theoretical calculations based on an ultimate strength flexural model. The joists are classified by how the provided amount of shear connection compares to the bottom chord yield force and by how the provided amount of shear connection in conjunction with the top chord capacity compares to the bottom chord yield force. Behavior typical of each classification is discussed. Correlation with previously conducted composite joist tests of similar configuration is also discussed. / Master of Science

One of the difficulties in solving E:MI problems is the lack of diagnostic tools available. In this thesis work, a tool, called Noise Separator, is developed, which can be used to decipher the differential-mode (DM) noise and the common-mode (CM) noise from the total noise. A noise separator hardware is built and tested. The results show that at least 50 dB rejection to either DM or CM noise is achieved for frequency ranging from 10 KHz to 30 MHz. With the aid of the Noise Separator, EMI filter design is made easier. / Master of Science