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RISS 인기검색어
- 검색키워드
- 저자 : Bostwick, Todd William (검색결과 2 건)
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Revisiting the dean: Byron Cummings and southwestern archaeology, 1893--1954 (Arizona, Utah)
Bostwick, Todd William Arizona State University 2003 해외박사(DDOD)
Byron Cummings was one of the more influential archaeologists who worked in the Southwest in the early 1900s, yet his long and colorful life had not been examined in a comprehensive biography. This study documents his professional career and chronicles his activities in exploration, education, museum development, administration, and writing. He and his students explored hundreds of miles of Arizona and Utah from 1906 to the early 1940s and excavated more than 150 archaeological sites. Unfortunately, many of those excavations were not reported. Cummings also was a very popular professor of Latin, Greek, and American Archaeology, first at the University of Utah (1893–1915) and then later at the University of Arizona (1915–1937). Many of his students considered Cummings one of the best teachers they had known. He had excellent administrative skills and served as a Dean for several years at both universities, and as President of the University of Arizona from 1927 to 1928. As Director of the Arizona State Museum for 22 years, he acquired more than 25,000 artifacts for its collections through excavations, purchase, and donations. One of the current State Museum buildings was constructed by Cummings using federal New Deal money in the mid-1930s. While President of the University of Arizona, he convinced the State Legislature to pass an Arizona Antiquities Act in 1927, which firmly established control of Arizona archaeology with the Arizona State Museum. That year he also started a graduate program in archaeology. In the 1930s, he clashed with other archaeologists from eastern institutions, as well as with some within the state, as competition for archaeological specimens intensified in Arizona. A tireless promoter and educator, Cummings contributed immensely to the growth of public awareness of Arizona archaeology.
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Investigation of Charge Transport and Mechanical Properties in Ion Associating Polymeric Materials
Bostwick, Joshua Everett The Pennsylvania State University ProQuest Dissert 2021 해외박사(DDOD)
Gel polymer electrolytes (GPEs) are ion-conducting polymers where the polymer matrix is swollen with a certain amount of solvent. While GPEs are able to take advantage of both the mechanical properties of the polymer matrix and the conductive properties of the solvent, they are limited due to the inverse relationship between the ionic conductivity (σo) and the modulus, diminishing their potential as next generation lithium-ion battery electrolytes. In this dissertation, we studied the fundamental properties of three different GPEs, molecular ionic composites (MICs) where the solvent is an ionic liquid (IL), single-ion-based MICs where the ‘solvent’ is poly(ethylene glycol), and cellulose-ionic liquid solutions, for their potential use as battery electrolytes.MICs utilize the mechanical and thermal stability of a rigid-rod sulfonated polyelectrolyte, poly(2,2′)-disulfonyl-4,4’benzidine terephthalamide (PBDT), and the high conductivity, electrochemical stability, and low volatility of ILs. This allows the MICs to produce a simultaneous high modulus (from the PBDT) and a high conductivity (from the IL). The first half of this dissertation explores how the change in either the PBDT concentration with a constant IL or the IL molecular volume (Vm) and chemistry with a constant PBDT concentration affects both the mechanical and charge transport properties of the MICs. The varying PBDT concentration MICs were produced via an ion exchange method to form 3 mm diameter cylinders (ingots) while the varying IL Vm MICs were produced via solvent casting to form six free-standing films. The single-ion PBDT membranes were also formed via the solvent casting method. The mechanical properties were measured using a combination of oscillatory shear rheology and uniaxial tensile tests (only for the films), while the dielectric properties and morphology of the films were determined through dielectric relaxation spectroscopy (DRS) and atomic force microscopy (AFM) respectively. Increasing the MIC PBDT concentration with a constant IL, 1-butyl- 3-methylimidazolium tetrafluoroborate (BMIm-BF4), showed a minimal change in dynamic glass transition temperature (Tg) of roughly 2 °C through rheology with its respective IL. This allowed for the MIC ionic conductivity (σo) at elevated PBDT concentrations to be within a factor of two of the neat IL at room temperature while also producing a shear modulus (G’) in the MPa range up to 200 °C. This is due to the MICs producing a two-phase environment corresponding to an IL-rich “puddle” phase and a PBDT-rich “bundle” phase, shown through the phase contrast in atomic force microscopy (AFM), where IL ions form alternating sheaths of cations and anions around each PBDT rod. As the PBDT concentration increases, these puddles shrink and produce a near single bundle phase. This potentially increases the polarizability of the MIC, shown by an increasing static dielectric constant, as well as allowing for more IL ions to contribute to σo shown by a decrease in the Haven ratio (HR), the ratio between the total number of charge carriers observed through NMR and the number conductive charge carriers that can be analyzed through the ionic conductivity.Incorporating ILs with different molecular volumes.
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