“Why not pitch the whole enterprise at the highest level possible?”: Speculative Radicalism and the Planetary Topics

This dissertation problematizes the hegemony of “critique” within the humanities in general and communication studies in particular. I argue that critique in the current mode, a reading and engagement practice that valorizes suspicion and purports to unmask allegedly concealed ideologies, does not equip scholars or students with the imaginative capacity necessary to confront the problems of the Anthropocene. Drawing upon the resources of speculative realism and speculative fiction, I propose speculative radicalism as an alternative practice. Speculative radicalism is an affirmative mode of reading, engagement, and theorizing that encourages the imagining of alternative future ways of living and modes of production, proceeding stepwise from a posited point of difference, or “novum.” Kim Stanley Robinson’s Mars Trilogy is offered as a model of invention in the speculative radicalist mode. With the goal of elaborating how speculative radicalism operates in this context, I repurpose the rhetorical topics of invention, or topoi. I argue that to fully appreciate the Mars Trilogy, one must understand that its applicable topics are, in fact, the planetary features of Mars itself: its gravity, landforms, and more. I develop and analyze this list of the planetary topics in the context of the Trilogy. In addition, I use the planetary topics to reevaluate established critical readings of the strategy video game series Sid Meier’s Civilization, as well as Robert Zubrin’s nonfiction space advocacy monograph The Case for Mars. I conclude that a reading of these artifacts informed by the planetary topics can yield more nuanced judgements than those produced by the prevailing style of academic critique; furthermore, this conclusion points the way toward the development of a speculative radicalist mode of engagement and imagination that is capable of meeting the challenges of the Anthropocene

Results of Propellant Mixing Variable Study Using Precise Pressure-Based Burn Rate Calculations

A designed experiment was conducted in which three mix processing variables (pre-curative addition mix temperature, pre-curative addition mixing time, and mixer speed) were varied to estimate their effects on within-mix propellant burn rate variability. The chosen discriminator for the experiment was the 2-inch diameter by 4-inch long (2x4) Center-Perforated (CP) ballistic evaluation motor. Motor nozzle throat diameters were sized to produce a common targeted chamber pressure. Initial data analysis did not show a statistically significant effect. Because propellant burn rate must be directly related to chamber pressure, a method was developed that showed statistically significant effects on chamber pressure (either maximum or average) by adjustments to the process settings. Burn rates were calculated from chamber pressures and these were then normalized to a common pressure for comparative purposes. The pressure-based method of burn rate determination showed significant reduction in error when compared to results obtained from the Brooks' modification of the propellant web-bisector burn rate determination method. Analysis of effects using burn rates calculated by the pressure-based method showed a significant correlation of within-mix burn rate dispersion to mixing duration and the quadratic of mixing duration. The findings were confirmed in a series of mixes that examined the effects of mixing time on burn rate variation, which yielded the same results

A Hybrid Medium Voltage Multilevel Converter with Parallel Voltage-Source Active Filter

In consequence of high semiconductor losses, grid-connected medium voltage power converters are typically operated at switching frequencies of several hundred Hertz per switch position. Therefore, conventional converter systems require bulky and expensive LCL-filters in order to meet the harmonic limits given by the grid code. It is only possible to reduce the LCL-filter costs by semiconductor current derating and operation at increased switching frequencies, leading to a reduced utilization and efficiency of the converter system. To overcome these disadvantages of conventional converter systems, the presented hybrid converter uses a parallel voltage-source active output filter and thus allows a significant reduction of the passive component demand. An excellent harmonic performance is achieved for the operation with small passive filter components, revealing the potential for increasing the power density and efficiency of high power medium voltage converters. As a result, significant reductions of the filter losses and passive components as well as an increased utilization are achieved compared to a reference LCL-filter based converter system

Highly Dynamic AC Current Control for Modular Multilevel Converters

A highly robust and dynamic control of the MMC grid currents is necessary to ensure grid stability. Based on a state space modelling of the MMC, a real time capable indirect modelbased control is presented. Measurements with a laboratory setup show the reliability even under disturbed grid conditions

FFT Bifurcation Analysis of Routes to Chaos via Quasiperiodic Solutions

The dynamics of a ring of seven unidirectionally coupled nonlinear Duffing oscillators is studied. We show that the FFT analysis presented in form of a bifurcation graph, that is, frequency distribution versus a control parameter, can provide a valuable and helpful complement to the corresponding typical bifurcation diagram and the course of Lyapunov exponents, especially in context of detailed identification of the observed attractors. As an example, bifurcation analysis of routes to chaos via 2-frequency and 3-frequency quasiperiodicity is demonstrated