This thesis is the sum of two parts. The first is a research paper that investigates the cultural phenomenon of the drummer boy during the American Civil War. Much attention and ink has been devoted to the drummer’s rudiments and battlefield role. I argue that upon surveying the wartime American culture more broadly, the drummer boy was not just a messenger, but a Christ figure for his time; I source contemporary articles, poems, songs, and novels to evidence this claim. The second section of my thesis is a reflection and analysis of my Masters Recital program. Here, I take time to reflect on the personal meaning of this particular performance and provide a brief analysis for each composition in turn

A stable isotope tracer technique was used to investigate the loss rate of methyl bromide in surface ocean waters. Unfiltered and 0.2 μm-filtered or autoclaved aliquants of Biscayne Bay seawater samples were spiked with ¹³CH₃Br at roughly 10–100 times ambient concentrations (50–800 pM) and incubated for 10–30 hours. The concentration of ¹³CH₃Br was monitored using gas chromatography with isotope dilution mass spectrometry, with CD₃Br as the isotope spike. Removal rates in unfiltered aliquants were significantly faster than in the 0.2 μm-filtered or autoclaved aliquants, indicating that some of the loss of methyl bromide was associated with particulate matter. Filtration experiments indicate that the particulate material responsible for methyl bromide loss is between 0.2 and 1.2 μm in diameter, suggesting that bacteria are likely to be responsible. The particulate-related removal of methyl bromide was inhibited by autoclaving, supporting a biological mechanism.

There are several possible approaches to enhancing the thermoelectric properties of skutterudite materials, most of which strive to reduce the total thermal conductivity of the structure in some way. Formulations of CoSb₃ skutterudite that incorporate alkali metals, alkaline-earth elements, or rare-earth elements as void fillers have achieved the highest reported thermoelectric figure of merit (ZT) values for n-type CoSb₃. For thermoelectric applications, devices that use IrSb₃-based materials as full legs or segments of legs could enable the utilization of a greater maximum temperature, as compared to CoSb₃-based devices. A series of n-type Ba_yIr₄Sb₁₂ compositions have been synthesized. Phase purity and elemental compositions are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Room temperature and high temperature thermoelectric properties are reported with a maximum ZT of about 0.8 at 750 ^oC (1023 K) and EPMA results suggest the maximum filling fraction for barium in Ba_yIr₄Sb₁₂ is around y = 0.3.

In light of the success of single-element filling of iridium-based skutterudite, double-element filling of the structure was investigated. The high temperature thermoelectric properties for the double-filled Ba_xYb_yIr₄Sb₁₂ and Ba_xEu_zIr₄Sb₁₂ skutterudites were compared to Ba_xIr₄Sb₁₂ single-filled skutterudites. Maximum ZT values for double-filled skutterudites increased as much as 25% over that of single-filled compositions. Phase purity and elemental compositions were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Room temperature and high temperature thermoelectric properties are reported with a maximum ZT of 1.0 at 750 ^oC (1023 K) for the Ba_0.15Eu_0.15Ir₄Sb₁₂ nominal composition, but EPMA results show that these skutterudites exhibit preferential filling for certain elements in the case of double-filling, such that Ba > Eu > Yb.

Skutterudite materials were processed by high energy ball milling to produce nanostructured powders. CoSb_{3 was used as a proof-of-principle material along with Co0.955Pd0.045Sb2.955Te0.045, Ba0.05Yb0.15Co4Sb12, and Ce0.9Fe3.5Co0.5Sb12. Each skutterudite was milled to a fine powder containing crystallites as small as 1 nm, with sample averages as low as ~20 nm. The powders were characterized by XRD, SEM, and TEM, then hot-pressed and measured for their high temperature thermoelectric properties. Hot-pressing conditions necessary for densification led to significant grain growth. Improvements in reduced thermal conductivity in each of the skutterudites examined were off-set by changes in the electrical properties of the samples. All observed increases in ZT over bulk materials were within the error of the measurement. Nanostructured skutterudite materials often behaved inconsistently and a majority of ball milled samples undergo reactions or phase transformations during high temperature measurements. Improving the ZT of skutterudite materials by ball milling to create nanostructures remains a challenge.}

In addition to further studies of new filler atoms in IrSb₃ skutterudites, composites and alloys offer promise of reduced thermal conductivities for enhancement of ZT. Preliminary results of alloying small amounts of cobalt in iridium-based skutterudite indicate that with optimization, these alloys have the potential to reduce thermal conductivity by the introduction of point defects in the structure. With more accurate band modeling, it could be possible to incorporate multiple approaches to reducing thermal conductivity into one sample, taking advantages of several different modes of phonon scattering.

Thermoelectric (TE) materials have been attractive to several research groups all over the world for their ability of directly converting thermal energy into electrical energy by the Seebeck Effect, and vice versa by the Peltier Effect. Due to their reliability and scalability, TE materials can be incorporated into devices for power generation or for cooling applications. Skutterudites have a complex crystalline structure in which the voids in the structure can be filled with foreign atoms. This doping technique has been shown to improve the TE performance of these "filled" skutterudite materials by disrupting the thermal conductivity without significantly impacting the electrical conductivity. Several studies have been done on filled CoSb3-based skutterudites and high ZT values have been obtained for these materials around 6000C. However, for thermoelectric applications that require higher operating temperatures, the more refractory IrSb3 with a peritectic decomposition at 11360C (1409 K) offers an advantage over CoSb3, which decomposes at 8740C (1147 K). Using the traditional synthesis method of melting, quenching, then annealing stoichiometric amounts of the elements to produce n-filled skutterudites, the obtained filling fraction was found to be significantly lower than the nominal filling fraction due to the high reactivity, or sometimes the high volatility, of the elemental fillers. In this experiment, we explored the effects of pre-reacting the reactive metal filler element with one of the elements in the skutterudite structure and utilized this precursor for the synthesis of the filled skutterudites to compare the relative successes of achieving targeted filling percentages of the voids in the structure. KyIr4Sb12 samples were synthesized using both the pure filler element, as well as the pre-reacted K-Sb compound. The phase purities, lattice parameters and elemental compositions were analyzed for each sample, calculated using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and electron microprobe analysis (EPMA), respectively. Their thermoelectric properties were also measured and calculated at room temperature and as a function of temperature ranging from room temperature to about 7500C (1023 K). The preliminary results obtained suggest that pre-reacting the potassium with antimony results in higher percentages of phase impurities and less efficient void filling in IrSb3 skutterudite. The highest ZT among all potassium-filled samples synthesized was measured to be 0.28 at 5000C (773 K) for K0.24Ir4Sb12. The data suggest that the cumulative thermoelectric properties of potassium filled IrSb3 are not as favorable as those IrSb3-based skutterudites filled with other atoms such as Ba or Eu. However, some of the potassium-filled samples achieved high room temperature carrier concentrations, similar to those seen in barium-filled samples, indicating that the potassium effectively participates in doping the structure. This work has compared and contrasted two methods for incorporating potassium fillers in the void spaces of IrSb3 skutterudite. While the ZT of potassium-filled samples was less than required for practical applications, this work does suggest that potassium may be useful in tuning electrical properties in samples that employ multiple element filling.

The relationship between the lattice parameter and the filling fraction was also studied on barium-filled and europium-filled IrSb3 skutterudite samples. A higher nominal filling fraction acquired a higher EPMA filling fraction and a higher lattice parameter until the filling fraction limit was reached. While barium displayed higher filling efficiency, europium possessed higher filling fraction limit. These preliminary results suggest that the optimization of multiple element filling to produce higher ZT is very obtainable with further studies on different single fillers.

The global ocean/atmosphere flux of methyl bromide has been estimated from shipboard measurements of the saturation anomaly. When such data are extrapolated globally on the basis of constant saturation anomaly, the ocean is a net sink for methyl bromide [Lobert et al, 1995]. The same data can also be extrapolated on the basis of steady-state production rate of methyl bromide in the water column, allowing regional and seasonal variations in temperature to affect the saturation anomaly. We have carried out this type of extrapolation, and we found that the oceans are a strong net source of methyl bromide to the atmosphere. The difference arises mainly due to slow degradation rates in water of higher latitudes. A reduction of the applied production rate by more than 35% is needed in order to switch the ocean from a source to a sink of methyl bromide. These results demonstrate the sensitivity of current estimates of oceanic flux to assumptions about methyl bromide production and destruction in the water column.