The Pressure-Volume-Temperature (PVT) for polymer/gas solutions is an important fundamental property of which accurate data measurement has not been reported until recently. The diffusivity, solubility, and surface tension are critical physical properties of polymer/gas solutions in understanding and controlling polymer processing such as, foaming, blending, and extracting reaction. However, the determination of these properties relies on accurate PVT data as a prerequisite. Due to the difficulties involved in measuring the specific volume while maintaining a sufficiently high pressure and temperature to achieve a single-phase polymer/gas solution, accurate PVT data or volume swelling measurement of polymer/gas solutions is not yet available. In this research, a new methodology was proposed and developed for direct measuring the PVT properties of polymer melts saturated with high-pressure gas at elevated temperatures. The ultimate goal is to develop and construct an apparatus that would provide more accurate fundamental properties through PVT measurement to the foaming industry, which is heavily involved with polymer/gas mixtures.

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

The Pressure-Volume-Temperature (PVT) for polymer/gas solutions is an important fundamental property of which accurate data measurement has not been reported until recently. The diffusivity, solubility, and surface tension are critical physical properties of polymer/gas solutions in understanding and controlling polymer processing such as, foaming, blending, and extracting reaction. However, the determination of these properties relies on accurate PVT data as a prerequisite. Due to the difficulties involved in measuring the specific volume while maintaining a sufficiently high pressure and temperature to achieve a single-phase polymer/gas solution, accurate PVT data or volume swelling measurement of polymer/gas solutions is not yet available. In this research, a new methodology was proposed and developed for direct measuring the PVT properties of polymer melts saturated with high-pressure gas at elevated temperatures. The ultimate goal is to develop and construct an apparatus that would provide more accurate fundamental properties through PVT measurement to the foaming industry, which is heavily involved with polymer/gas mixtures.

A numerical method based on the the method of characteristics for hyperbolic systems of partial differential equations in four independent variables is developed and used for solving time domain Maxwell's equations. The method uses the characteristic hypersurfaces and the characteristic conditions to derive a set of independent equations relating the electric and magnetic field components on these hypersurfaces. A discretization scheme is developed to solve for the unknown field components at each time step. The method retains many of the good features of the original method of characteristics for hyperbolic systems in two independent variables, such as optimal time step, good behavior near data discontinuities and the ability to treat general boundary conditions. The method is exemplified by calculating the time domain response of a few typical planar interconnect structures to Gaussian and unit step excitations. Although the general emphasis is on interconnect problems, the method is applicable to a number of other transient electromagnetic field problems governed by Maxwell's equations. In addition to the method of characteristics a finite difference scheme, known in mathematic circles as the modified Richtmyer scheme, is applied to the time domain solution of Maxwell's equations. Both methods should be useful for efficient full wave analysis of three dimensional electromagnetic field problems. / Graduation date: 1994

In the first part of this thesis we discuss classes of new exact NUT-charged solutions in four dimensions and higher, while in the remainder of the thesis we make a study of their properties and their possible applications. <br /><br /> Specifically, in four dimensions we construct new families of axisymmetric vacuum solutions using a solution-generating technique based on the hidden <em>SL</em>(2,R) symmetry of the effective action. In particular, using the Schwarzschild solution as a seed we obtain the Zipoy-Voorhees generalisation of the Taub-NUT solution and of the Eguchi-Hanson soliton. Using the <em>C</em>-metric as a seed, we obtain and study the accelerating versions of all the above solutions. In higher dimensions we present new classes of NUT-charged spaces, generalizing the previously known even-dimensional solutions to odd and even dimensions, as well as to spaces with multiple NUT-parameters. We also find the most general form of the odd-dimensional Eguchi-Hanson solitons. We use such solutions to investigate the thermodynamic properties of NUT-charged spaces in (A)dS backgrounds. These have been shown to yield counter-examples to some of the conjectures advanced in the still elusive dS/CFT paradigm (such as the maximal mass conjecture and Bousso's entropic N-bound). One important application of NUT-charged spaces is to construct higher dimensional generalizations of Kaluza-Klein magnetic monopoles, generalizing the known 5-dimensional Kaluza-Klein soliton. Another interesting application involves a study of time-dependent higher-dimensional bubbles-of-nothing generated from NUT-charged solutions. We use them to test the AdS/CFT conjecture as well as to generate, by using stringy Hopf-dualities, new interesting time-dependent solutions in string theory. Finally, we construct and study new NUT-charged solutions in higher-dimensional Einstein-Maxwell theories, generalizing the known Reissner-Nordström solutions.

In the first part of this thesis we discuss classes of new exact NUT-charged solutions in four dimensions and higher, while in the remainder of the thesis we make a study of their properties and their possible applications. <br /><br /> Specifically, in four dimensions we construct new families of axisymmetric vacuum solutions using a solution-generating technique based on the hidden <em>SL</em>(2,R) symmetry of the effective action. In particular, using the Schwarzschild solution as a seed we obtain the Zipoy-Voorhees generalisation of the Taub-NUT solution and of the Eguchi-Hanson soliton. Using the <em>C</em>-metric as a seed, we obtain and study the accelerating versions of all the above solutions. In higher dimensions we present new classes of NUT-charged spaces, generalizing the previously known even-dimensional solutions to odd and even dimensions, as well as to spaces with multiple NUT-parameters. We also find the most general form of the odd-dimensional Eguchi-Hanson solitons. We use such solutions to investigate the thermodynamic properties of NUT-charged spaces in (A)dS backgrounds. These have been shown to yield counter-examples to some of the conjectures advanced in the still elusive dS/CFT paradigm (such as the maximal mass conjecture and Bousso's entropic N-bound). One important application of NUT-charged spaces is to construct higher dimensional generalizations of Kaluza-Klein magnetic monopoles, generalizing the known 5-dimensional Kaluza-Klein soliton. Another interesting application involves a study of time-dependent higher-dimensional bubbles-of-nothing generated from NUT-charged solutions. We use them to test the AdS/CFT conjecture as well as to generate, by using stringy Hopf-dualities, new interesting time-dependent solutions in string theory. Finally, we construct and study new NUT-charged solutions in higher-dimensional Einstein-Maxwell theories, generalizing the known Reissner-Nordström solutions.

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This study was to investigate the removal efficiency and the feasibility of containing-EDTA solutions by O3 and O3/UV, advanced oxidation processes (denoted by AOPs). The operation parameters conducted in semi-batch reactor were as follows: ozone dose, pH, temperature and initial concentration of EDTA. The best mineralization and COD removal was found at pH= 9 when the pH values in O3 process was controlled at 3, 5, 7, 9 and 11. Addition of UV in O3 process for treating solutions containing EDTA was found not increasing the reaction rate but raising the COD and mineralization efficiency. In O3 process, the reaction rate was proportional to the ozone dose, it caused a higher mineralization. The higher the initial concentration of EDTA, the lower reaction rate, and the decreasing the mineralization was. Changing the temperature in reaction process was not obviously affected the removal of EDTA due to the lower activated energy found in O3 process. In O3/UV process, EDTA was decomposed very fast, but it still could not be mineralized the intermediates completely. The concentration of nitrate formed in this process was low. It is probably for high energy NH-containing bonds which is not easy break down by O3/UV. Thus, the major reactions in this process are the break of C-N bond, and followed by the break of C-H bond.