Flashblast™ (a registered trademark) is an intense broad spectrum pulsed light source developed by Maxwell Laboratories, San Diego, California which utilizes a Xenon flashlamp for emitting a mixed spectrum of ultraviolet, visible and infrared light. The project's objective was to determine the feasibility of ultra-high intensity light for improving food quality by reducing surface microbial contamination and selected mold metabolites (aflatoxins). Flashblast™ light was found to be highly effective in inactivating vegetative cells of E. coli, S. aureus, B. cereus and B. subtilis. Bacilli and A. niger spores were also susceptible to Flashblast light at somewhat higher fluences. Ultrastructural study with the scanning and transmission electron microscopes indicated that Flashblast™ treated gram-negative E. coli population is more susceptible to membrane damage when compared to other microorganisms. This suggests that photoinactivation involves effects on sensitive sites (genetic material) within the treated organisms which do not lead to significant changes in the microorganism morphology. Food acceptability studies on cheese, bread, strawberries and turkey breasts did not show a significant alteration in color, flavor and texture (p≤0.05). The results obtained with bread and strawberries showed commercial feasibility with an approximate 50% shelf-life extension. Flashblast™ treatment caused photodegradation of most aflatoxin types when multiple flash sequences were employed. It was concluded that full spectrum Flashblast™ light is highly effective for the inactivation of microorganisms and destruction of aflatoxins without causing undesirable sensory changes in foods. / Master of Science

The payment for nutritional services is one of the most critical issues facing the dietetic profession today. Several of the recent studies have focused on the fee assessment for nutritional services by hospitals but there has been only one published study that investigated the pricing structure of services in the context of the dietetic profession. However, what research that has been done clearly show that there is an important relationship between the concept of service and the role of the dietitian in the service sector, the pricing strategy in the service sector, the variables affecting the pricing structure and the pricing strategies for nutritional services. Therefore, the major purpose of this research was to determine those variables which have been identified as most influential in establishing fees charged by consulting dietitians and to establish guidelines on the price structuring of services offered in a private independent practice by a consulting dietitian. The major independent variables in this research postulated to affect the dependent variables, charge per hour to private and contract clients, charge per hour to private clients and charge per hour to contract clients. The dietetic profession will see increased competition for reimbursement for nutritional counseling services. This research provides questions in regard to specific pricing policies for nutritional consulting private practices. / Master of Science

The effect of genetic selection for milk yield on lactation yield, net energy balance (NEB) and on plasma growth hormone (GH), insulin (INS), prolactin (PRL), nonesterified fatty acids (NEFA) and glucose was studied in primiparous Holstein cows. Net energy balance was calculated and serial blood samples were collected at 0, 45, 90, 180 d postpartum (dpp) and 14 d of the dry period over a 7 h period via jugular cannulae. After 2.5 h of blood collection, growth hormone releasing factor (GRF) was administered at 0, 45, 180 dpp and 14 day of the dry period, while epinephrine was administered at 90 dpp. Nonesterified fatty acids were quantified in 90 dpp samples only. Basal and response periods for each hormone and metabolite were compared by analysis of variance. Milk yield was greater (P<.05), NEB was decreased (P<.05) and plasma GH was greater (P<.05) in selection cows (high-yielders) compared to control cows (low-yielders), while PRL, INS, glucose and NEFA were not different. Growth hormone increased in both groups in response to GRF at all days postpartum measured, while PRL, INS and glucose were not altered. Epinephrine administration at 90 dpp, stimulated an increase in plasma NEFA, glucose and INS in both groups. Control cows showed a greater (P<.01) INS response than selection cows. Results indicate differences exist in GH concentration between genetically selected high- and low-yielding Holsteins during early lactation, but the question remains if these differences are due to energy balance differences or differences in genetic merit for milk yield. / Master of Science

The objective of this research was to quantitatively assess the urinary excretion of glutamine and glycine conjugates in a free living population of young male adults, in order to establish a profile of detoxification via amino acid conjugation. Also, the effect of certain factors (vegetable, fruit, meat, and charbroiled food intake; tobacco, alcohol, caffeine, and marijuana use; exposure to chemicals and familial cancer incidence) on the urinary excretion of the amino acid conjugates were investigated. Three consecutive 24 hour urines were collected from 40 subjects who complied with a specific collection protocol. The urine samples were analyzed using a HPLC amino acid analyzer. The mean conjugated glutamine excreted was 1.30 mmole/24 hr or 8.74 x 10⁻² mmole/mmole creatinine/24 hr. The mean value for urinary conjugated glycine was 3.91 mmole/24 hr or 26.38 x 10⁻² mmole/mmole creatinine/24 hr. For glutamine conjugate excretion, vegetable, fruit, alcohol, chemical exposure and marijuana use showed marginally significant differences among their subgroups. For glycine conjugate excretion, meat, caffeine, chemical exposure, cancer and marijuana use showed marginally significant differences among their subgroups. An analysis of variance revealed a large degree of between-subject(inter) and within-subject(intra) variability. The coefficients of variation for glutamine and glycine for intervariabili ty were 51.1 and 53.4%, respectively, whereas the coefficients of variation for intra variability were 37.3 and 31.4%, respectively. Probably, the large variability masked any effects of diet, environment or genetics on the observed urinary conjugated amino acid excretion. / Master of Science

The practical applications of scheduling generally involve the optimization of more than one criterion. This thesis focuses on the bicriteria optimization problem of scheduling jobs on single and two machines. The optimization criteria that are considered are those of minimization of maximum tardiness and minimization of the total number of tardy jobs in the schedule. The former is considered as the primary criterion while the latter is considered as the secondary criterion. For the single machine problem, a search tree method is presented which is based on the implementation of some new dominance rules. Computational results presented show that the performance of this algorithm is better than that of an earlier work reported in the literature. For the two machine problem, a heuristic algorithm is developed to minimize maximum tardiness. Computational results are presented regarding the performance of this heuristic. A search tree method is developed for the optimization of the secondary criterion. This search tree method is similar to that for the single machine problem except that it does not use the dominance rules that were developed for the single machine case. Computational experience is presented for this algorithm. / Master of Science

Role strain, coping, and adaptational outcomes were examined for a sample of 205 eighth grade adolescents. Differences by gender and family type on amount of role strain, use of coping strategies, and levels of emotional stress and well-being in family and peer roles were identified. Results indicate gender differences in degree of strain experienced in the family role and in use of Social Support and Ventilation as coping strategies. Female adolescents report significantly greater strain than males in family roles. Females, in comparison to males, use Social Support to a significantly greater degree and Ventilation significantly less often as a coping response. Differences by family type were found for the use of Family Support as a coping strategy. Adolescents in single-parent families utilize Family Support as a coping strategy significantly less often than adolescents in two-parent families. Results are discussed and directions for future research are recommended. / Master of Science

The National Scientific Balloon Facility (NSBF) conducts scientific balloon flights. Scientific payloads ranging from a few hundred up to several thousand pounds suspended weight are flown over the southern United States. People living in these areas are subject to risk from these operations. A model has been developed to predict the risk associated with the ascent phase of a balloon operation. This model includes all of the significant factors that affect ascent phase risk. The model is automated in a computer program whose input contains all of the parameters and factors for a particular mission. The results of this model can be used to advise management personnel of the risk level for a particular balloon mission. This model can be used as a long range planning tool or on the day of launch to determine whether the mission risk level is acceptable. / Master of Science

Magnesium sulfide activated with europium and samarium is a candidate phosphor for laser stimulated personnel dosimeters. Optically stimulated luminescence (OSL) dosimeters are advantageous in that they provide a faster, isothermal dose measurement than conventional thermoluminescent dosimeters. The effects of activator concentration and chemical substituents are examined in order to increase OSL intensity, improve the OSL emission wavelength and to increase the chemical stability of the MgS lattice. In addition, UV photoluminescence and thermoluminescence of the MgS:Eu:Sm phosphor was investigated to improve the understanding of the optical processes in MgS:Eu:Sm phosphors. / Master of Science

Every one who has driven on a freeway has observed the phenomenon of lanechanging. This phenomenon is, of course, caused by the desire of most of the drivers not to be in a slow-moving lane. Therefore, the average driver who finds himself in such a lane moves into a neighboring faster lane, usually after a certain time-lag. This time-lag depends on the dynamic characteristics of the vehicle, the availability of acceptable gaps, and the driver risk, which is the value the driver places on the probability of collision during a maneuver, i.e. the higher the perceived probability of collision, the higher the time-lag. Modelling of the lane-changing phenomenon has been the objective of many investigators in the past. As will be shown later in this study, lane-changing is a very important component in highway traffic flow. In this study, a mathematical model to describe the lane-changing behaviour is suggested based on the lane-changing hypothesis that whenever there is a lane-changing maneuver, the average speed of the neighboring lane is faster than the average speed of the current lane. A set of data has been collected by a methodology which involves aerial photographic technique. The collected data are then used to test the validity of the lanechanging hypothesis, to calibrate and validate an existing lane-changing model, and to develop a gap acceptance function for freeway lane-changing maneuvers. / Master of Science

The complex and non-linear nature of blast fracturing have restricted common blast design mostly to empirical approaches. The code developed for this investigation avoids both empiricism and large memory requirement in order to simulate the pattern of interacting radial fractures from an array of shotholes, at various burdens and spacings, and in simultaneous and delayed modes. The resultant pattern is analyzed and a fragment size distribution calculated. The rules governing the distribution of radial cracks and the way in which they interact are based on model scale experiments conducted by various investigators. Calculated fragment size- distribution agree with data from the field. Powder factor dependence of fragmentation results is also well described by the model. The effect of discontinuities on rock fragmentation by blasting is also incorporated into the model. Discontinuities which are open and filled with air or soil-like material affect destructively the transmission of strain waves and propagation of cracks in the rock mass. These discontinuities can be incorporated into the simulation by inserting cracks to represent them. The cracks representing discontinuities will then terminate the cracks produced by blasting where they intersect. On the other hand, tight joints without filling material or with filling material but with a high bond strength and acoustic impedance close to that of the medium do not affect in a negative way the transmission of shock waves in the rock mass. A mathematical model was developed to treat these discontinuities which was based on principles from Linear Elastic Fracture Mechanics theory and Kuznetsov's equation which relates the mean fragment size obtained to the blast energy, hole size and rock characteristics. / Master of Science