An analysis tableau suitable for investigating flow-shop attributes is presented in detail 1. Geometric properties, inherent within the tableau, are employed using graph theory concepts in developing a heuristic algorithm for makespan minimization. Computer implementation of this algorithm revealed promising results when compared with several state of-the-art heuristic algorithms. The tableau can be conceived as a three-dimensional matrix with the first two indices consisting of job numbers (rows) and machine numbers (columns). The third index is used to distinguish processing times and accumulative makespan values. The matrix is as informative as the Gantt Chart and yet offers additional advantages when considering the flow-shop problem, such as: 1. Provides an instructional tableau format which is organized, systematic, and directly amenable for hand or digital-computer calculations, 2. Depicts computational contingencies for accumulative makespan values (individual job due-dates as well as flow-shop makespan), 3. Depicts machine and job dominances, 4. Allows for sensitivity analysis {effects of processing times upon accumulative makespan values), 5. Identifies critical-processing times, 6. Reveals where external improvements would be cost effective, 7. Representation is easily modified for job permutations, 8. Representation is not limited to small flow-shops (low number of jobs and/or machines), 9. Allows for additional insight when investigating heuristics, and 10. Can be used as an instructional- , managerial- , and/or a research- tool for analyzing flow-shop attributes. The tableau allows a macro-sensitivity analysis of the entire flow-shop. Specifically, the maximum increase in various processing times, without increasing the flow-shop make span, can be determined. This analysis utilizes graphical representations (segments and nodes) in matrix (tableau). Graphical representation is a convenient means for preserving the history of how each accumulative makespan value was mathematically generated. Concepts such as: partial-paths and critical-paths in conjunction with regions-of-influence are discussed in order to determine the interrelationship between the accumulative makespan values and the processing times, for a specific job sequence. / M. S.

The phenomenal growth in the community of computer users has focused attention on single user microcomputers as a means of alleviating overcrowding on multi-user mainframes. This thesis concerns the development of a microcomputer· for the Virginia Tech Computer Engineering Laboratory. The primary objective was to upgrade the presently used monitor level microprocessor stations to full fledged microcomputers with a comprehensive operating system. As a part of the overall study, dynamic RAM system design using VLSI controllers was investigated. A comparison of two popular controllers is presented. Another aspect investigated is floppy disk control strategies. A comprehensive analysis of various schemes is provided. A conclusion based on applicability and performance of the microcomputer developed is drawn and suggestions to further enhance its utility are made. / M. S.

The ultrastructure of the uterovaginal sperm storage glands of turkey hens was characterized. The ultrastructural morphology of these cells was monitored over an entire egg laying season. In addition, comparisons were made between glands from fertile and infertile hens. Based on ultrastructural observations, it was determined that cells of the uterovaginal sperm storage glands exhibit only a moderate level of metabolic activity. The limited presence of intracellular secretory products, along with an infrequently observed cellular release of secretory material, suggested that the effect of glandular secretion on spermatozoal survival was minimal. The density and degree of development of the apical microvilli, however, suggested that a primary function of glandular cells may be absorption of lumenal contents. The length of time that a hen has been producing eggs did not influence the ultrastructure of storage gland cells. The ultrastructural morphology of glands from hens collected immediately prior to commencement of egg production was similar to that of glands taken from hens that had completed an entire season. of egg production. Thus, the uterovaginal sperm glands were fully developed when hens started to lay eggs and remained fully developed for as long as the hens continued to lay. Aside from the observation that very few spermatozoa could be found in the uterovaginal sperm glands of infertile hens, no detectable ultrastructural differences were observed between glands from fertile and infertile hens. The uterovaginal sperm glands from infertile hens were observed to maintain the same degree of structural integrity and level of functionality as glands from fertile hens. Furthermore, there was no evidence of glandular microbial infections, nor was there evidence of an adverse immunological response at the level of the sperm glands. / M. S.

This investigation was concerned with the measurement and prediction of erosive burning. The theoretical models for erosive burning in composite propellants were reviewed. The experimental techniques which were cited in the literature for the measurement of erosive burning were also reviewed. Only the high-speed motion picture technique was found to have resolution sufficiently high to measure erosive burning accurately. The theory for the microwave burning rate measurement technique was also presented. Although this technique has never been applied to the measurement of erosive burning, it has high resolution and does not interfere with the internal flow over the propellant. For these reasons, microwave. interferometry was. recommended as the experimental method best suited to measure erosive burning. Utilizing the microwave technique, a preliminary design for an erosive burning tester was proposed. The proposed apparatus could generate crossflows from Mach 0.2 to Mach 1.0 over the propellant in the test section. A preliminary test plan for verifying the microwave measurement technique was presented. / M. S.

This research study examined the effect operational parameters, dissolved oxygen (D.O.) and food to microorganism ratio (F:M ratio) had on the thickening and dewatering from laboratory-scale and full-scale activated sludge treatment processes. Differences observed in sludge thickening and dewatering at CWWTP and BWWTP were investigated. Data was collected and operational parameters at full-scale facilities monitored. A laboratory-scale activated sludge reactor was constructed and operated on line with the CWWTP, which experienced filamentous bulking conditions since startup and operational parameters of the reactor monitored. Laboratory-scale experiments involved varying mixed liquor D.O. concentration and mean cell residence time (MCRT) and observing the resultant sludge thickening and dewatering characteristics. Increase in mixed liquor D.O. concentration, F:M ratio and reduction of MCRT at CWWTP resulted in improved sludge thickening and dewatering performance. Results showed sludge thickening characteristics were enhanced at D.O. concentrations greater than 3.0 mg/1 and less favorable at D.O. concentrations less than 2.0 mg/1. No trend correlation existed between aeration basin D.O. concentration and sludge dewatering resistance in the range of 3.0 to 7.0 mg/1. Correlation between laboratory-scale and full-scale activated sludge systems demonstrated that laboratory-scale reactor units can be. utilized to predict plant operational changes in relation to sludge thickening and dewatering performance. / M. S.

Although highway maps are commonly used, little research has focused on the effectiveness with which they are utilized. Route following and route planning are the two main uses of highway maps, and road symbolization is the information most desired by highway map users. Therefore, testing was conducted to determine relative effectiveness of different road symbolization systems in route following and route planning tasks. One black and white and two color road surface symbol hierarchies were employed on maps tested with 162 participants. It was hypothesized that both color hierarchies, one consisting of a part-spectral progression of hues (red-orange-yellow) and the other a full-spectral order (red-green-blue), would prove to be more effective than the black and white hierarchy, and that the part-spectral hierarchy would prove similarly superior to the full-spectral hierarchy. Overall results did not conclusively support either hypothesis. There was, however, significant variation in performance according to the purpose of use and among subgroups of the test population. These findings indicated that designing an optimal map for all purposes and map users may be an impossible task. The results also demonstrate that it is critical for the highway mapmaker to identify who will use the map he creates and the purpose(s) for which it will be consulted. / M. S.

No description available.

Research in job shop scheduling has concentrated on sequencing simple, single component jobs that require no coordination of multiple parts for assembly. However, since most jobs in reality involve some assembly work, scheduling multiple component jobs through an assembly shop, where both serial and parallel operations take place, represents a more realistic and practical problem. The scheduling environment for multiple component jobs in terms of routing, sequencing, and the pacing of common components may be quite complex, and, as such, requires special scheduling considerations. The purpose of this research is to evaluate scheduling policies for the production of assembled products in a job shop environment, termed "assembly shop". The specific scheduling policies examined include duedate assignment procedures, labor assignment procedures, and item sequencing rules. The sensitivity of these policies to product structure is also addressed. / Ph. D.

Morphological studies were carried our on thermotropic liquid crystalline copolyesters based on poly(ethyleneterephthalate) (PET) and para hydroxybenzoate (PHB), where PHB content varied from 0 mole percent up to 80 mole percent. The technique of chemical etching coupled with SEM and WAXS was utilized to obtain structural information. Morphological changes that occur when these materials are exposed to solvents such as dioxane or acetone and dye carriers were also studied using SEM. Electron microscopy results on the thermally pressed, quenched and chemically etched films indicate that selective chemical etching, i.e. etching of PET rich regions, occurs. This indicates a heterogeneous structure. An oversimplified molecular model has been proposed based on these results where at low PHB levels a PET rich phase is the continuous phase and at higher PHB levels (≥60 mole%PHB) a PHB rich phase is the continuous phase. SEM results on pressed, quenched, annealed and etched films show a "bricklike" structure similar to that seen when pure PET is chemically etched. WAXS studies show that crystallization is induced by solvent (etchant) at small etching times which indicates that the etching of PET rich regions is a two step process; (i) solvent induced crystallization, (ii) chemical etching. Dyeing studies carried out the PET/PHB systems using two different dye carriers indicate that dyeing occurs preferentially in the PET regions. Morphological studies on the dyed materials show a "puffed up" structure present only in the 50 mole% PHB material. / Master of Science

This study evaluated mating behaviors of turkeys, the effects of these behaviors on reproduction, the effects of the presence or absence of the opposite sex on reproduction and changes in serum luteinizing hormone (LH) and prolactin concentrations due to natural mating or artificial insemination. Male body conformation did not significantly affect male mating efficiency, whereas male sex drive was correlated with efficiency. Female sex drive, while positively correlated with the number of attempted matings, decreased following an incomplete or completed mating. Neither semen quality nor egg production was affected by degree of sexual activity. In males used for artificial insemination, the presence or absence of females did not affect any semen quality measurement. Egg production of artificially inseminated females was positively affected by male presence during the last third of the laying period, while fertility and hatchability of fertile eggs was not. Very few differences in serum LH or prolactin concentrations were observed following natural mating behaviors or artificial insemination. Serum LH and prolactin concentrations did not change following any male mating behavior. For mated females, a significant decrease in LH was observed in non-receptive hens following introduction of the male into the breeding pen. No changes in prolactin were observed following any female mating behavior. Although no differences were observed in LH concentration in males following semen collection, prolactin significantly increased in males maintained in the presence of females following this procedure. No changes in serum LH or prolactin concentrations were observed following artificial insemination of females. / Master of Science