Sexism and Imperialism in Mozart's Don Giovanni, Puccini's Madama Butterfly, and Blitzstein's Regina: A Performance Study

This dissertation project comprises three major operatic performances and an accompanying document; a performance study which surveys aspects of sexism and imperialism as represented in three operas written over the last three centuries by examining the implications of prejudice through research as well as through performances of the major roles found in the operas. Mr. Eversole performed the role of Sharpless in the 2014 Castleton Festival production of Madama Butterfly (music by Giacomo Puccini, libretto by Luigi Illica and Giuseppe Giacosa), conducted by Bradley Moore. In 2015, Mr. Eversole sang the title role in four performances of Mozart and Da Ponte’s Don Giovanni with the Maryland Opera Studio at the Clarice Smith Performing Arts Center, conducted by Craig Kier. Also as part of the Maryland Opera Studio 2015-16 season, Mr. Eversole appeared as Oscar Hubbard in four performances of Marc Blitzstein’s Regina, an adaptation of Lillian Hellman’s 1939 play, The Little Foxes. These performances were also conducted by Craig Kier. The accompanying research document discusses significant issues of cultural, geographical, and sexual hegemony as they relate to each opera. It examines the plots and characters of the operas from a postcolonial and feminist perspective, and takes a moral stance against imperialism, sexism, domestic abuse, and in general, the exploitation of women and of the colonized by the socially privileged and powerful. Recordings of all three operas can be accessed at the University of Maryland Hornbake Library. They are: Giacomo Puccini’s Madama Butterfly (the role of Sharpless) July 20, 2014, Castleton Festival production, Bradley Moore, Conductor Castleton, Virginia Wolfgang Amadeus Mozart’s Don Giovanni (title role) November 22nd, 2015, Maryland Opera Studio, Craig Kier, Conductor Clarice Smith Performing Arts Center, UMD Marc Blitzstein’s Regina, (Oscar Hubbard) April 8th, 8016, Maryland Opera Studio, Craig Kier, Conductor Clarice Smith Performing Arts Center, UMD

INVESTIGATION OF MAGNESIUM ION CHARGE STORAGE MECHANISM IN MANGANESE DIOXIDE

Magnesium (Mg) battery is considered as a promising candidate for the next generation battery technology that could potentially replace the current lithium (Li)-ion batteries due to the following factors. Magnesium possesses a higher volumetric capacity than commercialized Li-ion battery anode materials. Additionally, the low cost and high abundance of Mg compared to Li makes Mg batteries even more attractive. Moreover, unlike metallic Li anodes which have a tendency to develop a dendritic structure on the surface upon the cycling of the battery, Mg metal is known to be free from such a hazardous phenomenon. Due to these merits of Mg as an anode, the topic of rechargea¬ble Mg batteries has attracted considerable attention among researchers in the last few decades. However, the aforementioned advantages of Mg batteries have not been fully utilized due to the serious kinetic limitation of Mg2+ diffusion process in many hosting compounds which is believed to be due to a strong electrostatic interaction between divalent Mg2+ ions and hosting matrix. This serious kinetic hindrance is directly related to the lack of cathode materials for Mg battery that provide comparable electrochemical performances to that of Li-based system. Manganese oxide (MnO2) is one of the most well studied electrode materials due to its excellent electrochemical properties, including high Li+ ion capacity and relatively high operating voltage (i.e., ~ 4 V vs. Li/Li+ for LiMn2O4 and ~ 3.2 V vs. Mg/Mg2+). However, unlike the good electrochemical properties of MnO2 realized in Li-based systems, rather poor electrochemical performances have been reported in Mg based systems, particularly with low capacity and poor cycling performances. While the origin of the observed poor performances is believed to be due to the aforementioned strong ionic interaction between the Mg2+ ions and MnO2 lattice resulting in a limited diffusion of Mg2+ ions in MnO2, very little has been explored regarding the charge storage mechanism of MnO2 with divalent Mg2+ ions. This dissertation investigates the charge storage mechanism of MnO2, focusing on the insertion behaviors of divalent Mg2+ ions and exploring the origins of the limited Mg2+ insertion behavior in MnO2. It is found that the limited Mg2+ capacity in MnO2 can be significantly improved by introducing water molecules in the Mg electrolyte system, where the water molecules effectively mitigated the kinetic hindrance of Mg2+ insertion process. The combination of nanostructured MnO2 electrode and water effect provides a synergic effect demonstrating further enhanced Mg2+ insertion capability. Furthermore, it is demonstrated in this study that pre-cycling MnO2 electrodes in water-containing electrolyte activates MnO2 electrode, after which improved Mg2+ capacity is maintained in dry Mg electrolyte. Based on a series of XPS analysis, a conversion mechanism is proposed where magnesiated MnO2 undergoes a conversion reaction to Mg(OH)2 and MnOx and Mn(OH)y species in the presence of water molecules. This conversion process is believed to be the driving force that generates the improved Mg2+ capacity in MnO2 along with the water molecule’s charge screening effect. Finally, it is discussed that upon a consecutive cycling of MnO2 in the water-containing Mg electrolyte, structural water is generated within the MnO2 lattice, which is thought to be the origin of the observed activation phenomenon. The results provided in this dissertation highlight that the divalency of Mg2+ ions result in very different electrochemical behaviors than those of the well-studied monovalent Li+ ions towards MnO2.