Dissertation Defenses

Doctoral students who have an upcoming dissertation oral defense are posted here. So why not take this opportunity to learn about the research that our graduate students are doing!

Dissertation Defense for Ashley Hanlon

Program: CHEMISTRY: PHD

Department Contact Email: cindi.rohwer@unh.edu

Defense Title: DESIGN AND SYNTHESIS OF POLYMERIC NANOSTRUCTURES USING SINGLE-CHAIN TECHNOLOGY AND CONTROLLED ARCHITECHTURES

Defense Date and Time: 03/29/17 1:00 pm

Defense Location: Parsons Hall, Room W131

Defense Advisor: Professor Erik Berda


Defense Abstract: With the increasing appeal of nanotechnology, there is a demand for development of synthetic techniques for the fabrication of nanosized objects that allow for precise size control and tailored functionalization. To this end, the collapse or folding of single polymer chains into architecturally defined nanostructures is a rapidly growing research topic in polymer science. Many synthetic approaches have been developed for the formation of single-chain nanoparticles (SCNP), and a variety of characterization methods and computational efforts have been utilized to detail their formation and probe their morphological characteristics. Interest in this field continues to grow partially due to the variety of potential applications of SCNP including catalysis, sensors, nanoreactors, and nanomedicine. While numerous developments have been made, the field is continuing to evolve, and there are still many unanswered questions regarding synthesis and characterization of SCNP. This dissertation serves to first identify recent accomplishments in the synthesis and characterization of SCNP, then to distinguish areas that are in need of advancement and innovation that we focused on to move this field forward. This includes exploring more complex synthetic strategies, obtaining folding control, employing nanoparticle functionalization, developing scalable methods, investigating hierarchical self-assembly of SCNP, and exploiting unique characterization techniques and in-depth simulations.


 

Dissertation Defense for Kimberly Aviado

Program: NRESS:ENSTUDIES: PHD

Department Contact Email: Lynne.Cooper@unh.edu

Defense Title: Magma genesis beneath active continental rifts

Defense Date and Time: 03/30/17 1:00 pm

Defense Location: James Hall 254

Defense Advisor: Julie Bryce, Samuel Mukasa


Defense Abstract: The East African Rift System (EARS) and the West Antarctic Rift System (WARS) are two of the largest continental rift systems on Earth, but the processes driving rift dynamics remain controversial. Rift-related magmatism has traditionally been attributed to anomalously hot mantle plumes actively rising from the deep mantle beneath both regions, but alternative explanations highlight the role of chemically heterogeneous, easily-fusible mantle components in driving magma genesis in the absence of significant thermal anomalies. These heterogeneous mantle domains may be linked to the complex tectonic histories of continents, which often involve multiple stages of accretion and recycling of materials between the crust and the mantle. In this dissertation, geochemical investigations of rift-related volcanic rocks provide new insight into the nature of the mantle underlying the two active rifts. Particularly, the role of volatiles (H2O and CO2) is highlighted due to their ability to enhance mantle melting during rift-related decompression.

In Chapter II, geochemical information from submarine and subaerial lavas in the Ross Embayment of West Antarctica provide evidence that volatilized, recycled mantle domains generated during ancient long-lived subduction along the paleo-Pacific margin of Gondwana are key components in the temporally evolving source of Cenozoic magmas. In Chapter III, the first rift-wide study of magmatic volatiles measured in olivine-hosted melt inclusions confirms that the West Antarctic mantle is enriched in H2O and CO2, and links the production of hydrated and carbonated components to subduction-related processes. These results provide a compelling link between continental assembly, the production of easily fusible, heterogeneous chemical domains in the sub-continental lithospheric mantle (SCLM) and upper mantle, and rifting. These links are further explored in Chapter IV, in which the elemental and isotopic (Sr-Nd-Hf-Pb) systematics of mantle xenoliths from the East African Rift System (EARS) illustrate that the SCLM bears witness to a complex history involving Proterozoic melt depletion events, Pan African continental assembly, late-stage metasomatism, and plume impingement. These results demonstrate that SCLM serves as an important long-lived host of heterogeneous recycled materials that are sampled throughout multiple episodes of convergence and breakup.

Collectively, these chapters suggest that ongoing rifting and magmatism in the EARS and the WARS involve the heterogeneous SCLM, rather than having exclusively deep plume origins. These processes emerge as a consequence of the complex, multistage evolution of continents.


 

Dissertation Defense for Kevin Weinman

Program: HISTORY: PHD

Department Contact Email: larademarest@unh.edu

Defense Title: RANCHLAND METROPOLIS: PRIVATIZED GROWTH IN SUBURBAN METROPOLITAN DENVER, 1950-2000

Defense Date and Time: 04/14/17 2:30 pm

Defense Location: Horton 422

Defense Advisor: Professor Kurk Dorsey


Defense Abstract: This dissertation studies the causes and effects of rapid and uncoordinated suburban growth in metropolitan Denver, Colorado after the Second World War. The region experienced sprawling, low-density residential development on its periphery despite a powerful wave of anti-growth sentiment and that swept the state in the sixties and seventies. This study argues that this resulted from the difficulties experienced by Coloradans in reconciling a number of their cherished ethics: individual freedom and the sanctity of property rights versus a nascent environmentalism, fervent pursuit of wealth and economic opportunity versus an enduring celebration of the state’s traditional ranching heritage and rural character, and a preference for local control versus a desire for more comprehensive regional solutions to the problems of growth.
The pace and type of suburban growth and development in metropolitan Denver emerged neither from intentional strategies nor a dominant development ethos. Instead, decades of indecisiveness and inaction at the state and county levels subjected the Denver metropolitan area to exogenous forces that filled the void. Outside corporate real estate developers privatized much of the process of the state’s suburban growth by acquiring large plots of ranchland in unincorporated areas, creating and controlling an unprecedented number of governmental entities called “special districts” to provide infrastructure and public services to their developments, and designing and building enormous communities that were cities in all but name. These “invisible suburbs” overwhelmed county, regional, and state efforts to integrate these new communities seamlessly into the metropolitan area. Privatized development carried socioeconomic, civic, financial, and environmental implications for the region and its residents.
This study focuses upon Denver’s southern suburbs, particularly those located in Douglas County, the nation’s fastest growing county during the late twentieth century. It analyzes state and local government records and reports, United States Census Bureau population and local government data, voting records, corporate publications, legal records and correspondence, and newspaper accounts to illustrate the efforts and struggles of the region’s residents and governments to contend with growth. It combines elements of business, environmental, public policy, and urban history to add to the historical literature of late-twentieth century American suburbanization.


 

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