Several methods have been developed to determine the cyclic oligomer content in PET. Isolation procedures can be classified as those involving extraction, such as with solvents like chloroform, dioxane, and xylene, and those involving dissolution followed by precipitation in solvents like dimethylformamide and 1-methylnaphthalene. The amount of cyclic oligomer obtained is largely dependent upon the method used, as well as the type, drawing, and thermal history of the PET used.Various methods for separation of cyclic oligomers have also been developed using GPC and thin-layer chromatography. / Master of Science

The research explored the long-term relationship between FDI, GDP and host country employment by using sector-wise panel data from 1991 to 2017 in Namibia. The study applied unit root testing and Cointegration test to test for the presence of a cointegration relationship between the variables. Also, a vector autoregression model short-run causality among the variables was examined. In the end, Impulse response functions are estimated. The research found both a short term and long-term causality going from FDI inflow to employment. Impulse responses show that both GDP and employment respond positively to an exogenous shock in FDI inflow. However, the employment response to FDI inflow shock is smaller than that of GDP response. The paper also concludes that FDI has no causal effects on economic growth in Namibia. It means that economic growth is not contributed by the FDI significantly the results in this research have some significant policy implications. Therefore, as the results suggest that the FDI inflow has a positive impact on employment, because of the results, the researcher also recommends that Namibia pursue the policy of attracting foreign firms aggressively and create all the conditions required for attracting foreign direct investment in order to create further employment opportunities.

The U. S. Navy's surface combatant force is built on a base of about 150 ships. Current projections for surface force commissionings and retirements indicate a need for an affordable variant of the Navy's mainstay battle force surface combatant, DDG 51. Fleet accessions will not keep pace with ship retirements to maintain required force levels unless the acquisition cost of the ships can be reduced. In addition, by also reducing operations and support costs, the Navy can ensure that a low cost alternative to DDG 51 generates cost savings over the entire ship's life cycle. <p>This study has been conducted in an effort to develop a concept design for a low cost surface combatant to be used by the United States Navy as an alternative to DDG 51. The design endeavors to meet stated Navy objectives for surface combatant affordability and capability. <p>Affordability is not simply a function of cost. It is instead a more complex measure which is dependent on factors including unit costs, budgets t and force structures. Thus, changes to any or all of these basic components can alter the affordability definition within any given application or context. The budget and force levels for the next 20 years are projected to decline, while unit costs continue to rise. For this reason, lower cost alternatives must be pursued in order to balance the affordability equation and allow required force levels to be maintained within budgetary constraints. <p>Acquisition cost for a DDG 51 low cost alternative should be less than $2 billion (in FY 91 dollars) for the firs t ship. This high initial cost would be attributed to the research, development, and design costs associated with a new ship design, as well as the actual construction costs for the first ship. Acquisition costs for follow ships should average around $750 million, or $100 million less than DDG 51. Overall life cycle costs should represent at least a 10% improvement over DDG 51. / Master of Science

Industrial toxicity has become a major environmental subject over the past decade. Although much research and data have been collected and published for the manufacturing type industries, minimal data is currently available concerning the possible toxics that may be associated with coal mining industry NPDES discharges. Thus, in this report, an environmental toxicity assessment with respective data shall be presented on the three major constituent sectors of the coal mining industry in Southwest Virginia of which includes mines, preparation plants and refuse facilities. The mines category shall include both surface and underground facilities. The preparation plants sector will cover the traditional railroad siding loadout type facilities, along with the modern clean coal processing preparation plants. Valley and side fill configuration, coarse and combined refuse fills and coal refuse impoundments shall be presented in the refuse facility categorization. Reference source data and specific information from a Virginia Coal Association Taxies Monitoring Program study are presented to show that the effects of toxicity in the coal mining associated NPDES effluents are minimal and not a serious problem. The conclusions of this report shall show that through enforcement of better management practices within the coal industry in Southwest Virginia that toxicity can be virtually eliminated in NPDES outfalls. / Master of Science

Master of Science

Master of Science

Master of Science

A microprocessor based bus protection scheme has been proposed for a single bus system which employs a new technique to overcome the problem of current transformer saturation. The protection scheme uses a combination of the percentage differential current principle and the phase comparison principle. A sampling rate of 1440 Hz is used. Existing algorithms for a saturation detector are reviewed and a new saturation detector has been developed. This new saturation detector employs the slope difference of the secondary current to determine the CT state. It has a high sensitivity and can reveal early (one-eighth cycle) saturation. With the incorporation of this new saturation detector, the bus relay can make a correct decision for either an internal or an external fault in the presence of current transformer saturation in a half cycle in most cases. The bus protection scheme has been coded in Fortran and tested against data produced from EMTP. The simulated results from eight sets of data are presented in this thesis. All cases show that the bus protection scheme works correctly. The algorithm for the new saturation detector will be implemented using a 32-bit microprocessor by Mr. Paul A. Dolloff. / Master of Science

A study of photon production in multi-hadronic final states has been made at center-of-mass energies from 55 to 58 GeV with the AMY detector at the KEK e+e- storage ring TRISTAN. / Ph. D.

This thesis reports on the results of thermal, optical, and spectroscopic studies on poly(vinylidene fluoride)/poly(3-hydroxybutyrate) (PVDF/PHB) blends prepared by melt and solution blending techniques. The blends exhibit - a single, composition dependent Tg. Dynamic crystallization studies indicate that PVDF crystallizes first in all blends containing more than 30% PVDF, and that the blends exhibit single phase behavior in the liquid state. Studies of the melting of isothermally crystallized samples indicate a melting point depression for melt blended PVDF/PHB but no equilibrium melting point depression for the solution blends. Growth rate studies on the α phase of PVDF reveal that its radial growth rate decreases with increasing PHB blend content. Morphological studies demonstrate that the ring spacing of the PVDF α phase increases with increasing temperature and PHB blend content. The different behavior of the meit and solution blends and the previous findings on the thermooxidative degradation behavior of PHB by Kunioka and Doi [1] indicated that PHB may have degraded during the melt blending process. NMR spectra reveal that PHB's chemical composition had not been affected by either blending procedure, but intrinsic viscosity studies indicate a dramatic decrease in PHB's viscosity average molecular weight after melt blending and a smaller decrease after solution blending. FT-IR studies were conducted to determine if PHB did crystallize in the same temperature range as PVDF. FT-IR spectra reveal PHB does crystallize in the same temperature range as PVDF in the solution but not in the meit blends, and the PVDF γ phase content is higher in the solution blends. Finally, TGA studies were performed to determine the effect of PVDF on the degradation of PHB. These findings indicate that PVDF retards the rate of PHB degradation in both types of blends. / Master of Science