This investigation consisted of a study of the kinetics of propylene disproportionation over a tungsten oxide on silica catalyst. A catalyst of ten percent WO₃ on silica gel (223 square meters per gram B.E.T. surface area) was used in a microcatalytic reactor. Electron probe scans of the commercially prepared catalyst showed that the standard liquid impregnation technique used in preparation of this catalyst can result in large radial variations in the distribution of the promoter within the pellet. Both flow and pulse reactor techniques were used. It had been reported that external mass transfer effects could not be eliminated in this system. Here linear velocities in excess of those used previously were investigated, and it has been found that both external and intraparticle mass transfer effects can be eliminated, though exceptionally high linear velocities are required to eliminate the external mass transfer effects. Initial rate data were obtained for the disproportionation of propylene by this catalyst. Temperatures of 399° to 454° Centigrade and pressures from one to nine atmospheres were used. The experimental data were well correlated by assuming that a Langmuir-Hinshelwood, dual-site surface reaction was the rate controlling step in the reaction mechanism. The mechanism parameters and their temperature dependence were extracted from the experimental data using a linear least squares technique. An apparent activation energy of 24.73 Kcal per mole was found for this catalytic system. During the initial contacting of freshly activated samples of this catalyst with propylene, significant increases in disproportionation activity were observed for periods up to twenty four hours. The rate of catalyst break-in was found to depend on both the temperature and pressure with an activation energy of 47.17 Kcal/mole and a first order propylene partial pressure dependency. Data are presented to establish that both a reduction of the catalyst to WO₂.₉ and the strong adsorption of an olefin are responsible for this period of transient activity. Prior reduction to the normally thermodynamically unfavorable oxidation state of WO₂ was found to give a thirty percent increase in the steady-state activity of this catalyst. The strong adsorption of an olefin was found to be at least partly reversible in an inert atmosphere. / Doctor of Philosophy

This thesis is in an attempt to realistically model a real-time digital generator which interfaces to an analog system simulator and which consists of the synchronous machine and its peripheral controllers such as the exciter and the governor-turbine subsystems. In this work, the exciter, the synchronous machine, the machine dynamics and the governor are modeled in detail while a simplified model of the turbine is used. The synchronous machine, the main component of this simulation, solves the discretized Park's machine equations which include flux derivative tenns and tenns pertaining to the two amortisseur windings. Treatment of saturation effects in the mutual inductances is also discussed. The Park's model is arranged to obtain a field voltage and machine armature cutTent input - machine tenninal voltage output structure, where the armature current and terminal voltage are rotor based quantities (i.e. in d-q domain). In order to interface the Park's machine model to the analog system model, the Park's and inverse Park's transformation are implemented by software modules. The implementation of a prototype model generator using a Motorola 68020 microprocessor and fast computer peripherals is discussed. The results of the digital computer simulation in real-time for the generator model under various operating conditions are presented. / Master of Science

ln the last several years, considerable attention has been paid to the study of dispersion-flattened single-mode fibers which offer a high transmission capacity with low losses through a wide range of wavelengths. However, the existing designs are sensitive to bending and manufacturing tolerances, and are not truly single-mode at most wavelengths of interest. To remedy these problems a new series of broadband dispersion-flattened truly single-mode fiber designs are proposed. These fibers have both dispersion-shifted and dispersion-flattened features with low splice and bend losses. Results demonstrating a total dispersion of ±0.97 ps/km-nm over the entire spectral range between 1.31 μm to 1.66 μm are presented. Such dispersion-flattening is achieved while simultaneously maintaining a mode-field radius of 3 μm to 5 μm in the dispersion-flattened wavelength range. The most significant achievement is that the proposed muIti-clad fiber design is strictly single-mode and splice and bend losses are smaller than those of double-clad, triple-clad, and quadruple-clad fibers with the same value of dispersion. Ultralow dispersion fibers, whose chromatic dispersion and the first and second-order derivatives of the chromatic dispersion are zero at 1.5 μm or 1.55 μm, are described. This effectively increases the laser emission tolerance. Ultralow dispersion fibers open the way to wavelength multiplexing with currently available inexpensive multifrequency lasers, either in local or long distance networks. These fibers also have low splice and bend losses compared to double-clad, triple-clad, and quadruple-cIad fibers. An inverse waveguide synthesis program, which can trace multiple objective functions and optimize multiple parameters simultaneously, is developed. An objective function is applied, for the first time, to optimize the dispersion-flattened single-mode fiber index profile with respect to: (1) minimum dispersion, (2) the wavelengths of zero-dispersion, (3) maximum width of dispersion-flattened window, (4) maximum layer index difference less than 0.8%, and (5) layer thickness larger than 3.5 μm. The accuracy of chromatic dispersion calculations in dispersion-flattened fibers is evaluated. lt has been shown that the accuracy of approximate methods is influenced not only by the index differences, but also by their derivatives with respect to wavelength. The matrix method and direct numerical integration of the wave equation are used to compute the mode propagation constants, cutoff frequencies, field distributions, mode-field radius, and splice loss, and carry out production tolerance analysis for multi-clad step-index fibers and graded-index fibers, respectively. Detailed analysis and optimized fiber data are presented. / Ph. D.

This article investigates the influence of competition on price and product quality among Austrian camping sites, a market characterized by both horizontal (spatial) and vertical product differentiation. Theoretically, the effect of competition on quality is ambiguous and depends on the degree of cost substitutability between output and quality. Estimating a system of equations shows that intense competition has a positive impact on product quality and a negative effect on prices (conditional on quality). As high quality is associated with high prices, the total effect of competition on prices is rather small.

Based on the political economy of the media perspective, this paper explores the media coverage of wealth and inheritance taxation over the early 21st century (2000 to 2018) based on a large-scale corpus of seven German daily and weekly newspapers. Germany is a useful case study, being one of the most unequal countries in the Eurozone area in terms of wealth inequality. Drawing on text mining methods and corpus linguistics, it shows that wealth and inheritance taxation is a relatively infrequent topic over the entire period, with the exception of a few intense months of increased reporting. On the occasions that the media do report on the topic of wealth and inheritance taxation, it is mainly covered in terms of a political debate. This debate centres on the politics of a possible reform process and the connected difficulties of finding compromise between different actors, rather than focussing on the potential economic impact. Furthermore, this paper explores the power of agents (both on the organisational and individual level) as the primary definers of social reality. It shows that market-liberal and conservative organisations and economists dominate the news over social-democratic and left-wing ones. Overall, the findings indicate a hostile news coverage concerning the introduction of wealth taxation and the increase of inheritance tax. / Series: Department of Economics Working Paper Series

This article explores how a public service broadcasting company, namely ORF in Austria, has dealt with the challenges created by the dual system. An investigation of market requirements, public programming mandate, cost structure and financing needs reveals how economic and political constraints are interrelated. To illustrate this phenomenon, we focus on programming, specifically on the highly successful genre of popular folksy music ('Volkstümliche Musik'). Opinions of decision-makers responsible for programming strategies at the Austrian PSB company are linked with a detailed empirical analysis of one prosperous production within that genre. This enables us to draw a number of conclusions on the strategies pursued by public service broadcasting companies to master the changed market conditions and draw attention to so far unattended topics. / Series: Department of Economics Working Paper Series