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

Pokeweed, a widely used wild vegetable, was gathered on a weekly basis during the harvesting season (May 26 through August 11, 1982) and analyzed for calcium, magnesium, phosphorus, iron, zinc, and oxalic acid. Since pokeweed and spinach are considered to be of similar eating quality, a comparison was made to like nutrient values of spinach. Pokeweed leaves produced the highest amount of phosphorus, zinc, and iron and the least amount of oxalic acid during early growth (May 26 through June 2, 1982) allowing these minerals to be more available than during the remainder of the growing season. Pokeweed leaves contained the highest amount of calcium and magnesium during the middle part of the harvesting season (July 21 and July 28, 1982). Pokeweed leaves contained amounts of calcium, magnesium, phosphorus, iron, and zinc comparable to spinach and half the oxalic acid content of spinach leaves. Pokeweed leaves may be considered an important contributor of minerals to human nutrition since pokeweed leaves con- tained a larger percentage (wet weight basis) of the U.S. RDA for calcium, zinc, and magnesium than did spinach leaves. / M.S.

A wooded 7.8 acre parcel located in Northern Virginia near the Potomac River is bordered by a National Wildlife Refuge and provides a setting for ''A Walk through the Woods", a place for a single family to live. As one enters the site, travels along the entrance road and moves through the house, stimulating and dynamic visual experi~ ences occur. Physically, the residence is a linear horizontal structure with a natural stepping of rooms in plan and elevation. Characteristic of the residence are extroverted experiences, contrasts between openness and closure, transitions from outside to inside, rooms well-lighted by daylight and rhythmic experiences as one travels from / common areas to personal areas along a path not unlike a path through the forest. The site, of rolling terrain bisected by small streams, encompasses a knoll from which the house evolved. The structure is compatible with nature on the outside and incorporates nature on the inside. At times the house and its surroundings almost become one. / Master of Architecture

An analysis of the influence of undercutting on the stress concentration factor for undercut gears using the finite element method is presented. The models used are in the shape of a whole gear with three teeth. The middle tooth is loaded assuming single-tooth contact. Thirty seven finite element models were used to compute stress concentrations in gear teeth. The results for non-undercut gears were compared with the Dolan and Broghamer results, and were not more than 9.5 percent different. The results are expressed in the form of a linear relationship giving the stress concentration factor at the root fillet as a function of the geometry of the tooth. It has been verified that this equation is an accurate formula for both undercut and non-undercut gears with nominal proportions. / Master of Science

Ph. D.

M. S.

M. S.

M. S.