Theses and Dissertations at Montana State University (MSU)
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Item Developments in electrically conductive bio-composites for use in additive manufacturing(Montana State University - Bozeman, College of Engineering, 2019) Arroyo, Jesse Whitney; Chairperson, Graduate Committee: Cecily Ryan; Cecily Ryan was a co-author of the article, 'Incorporation of carbon nanofillers tunes mechanical and electrical percolation in PHBV:PLA blends' in the journal 'Polymers' which is contained within this thesis.With the growth of rapid production methods, such as additive manufacturing, petroleum derived plastics are becoming ever more prevalent in consumer homes and landfills. As the industry grows, research into a more circular approach to designing and using materials is critical to maintaining sustainability. Bioplastics such as poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(lactic acid) (PLA) provide material properties comparable to petroleum derived plastics and are becoming more common in the additive manufacturing field. Biobased fillers, such as bio-derived cellulose, lignin byproducts, and biochar, can be used to modify the thermal, mechanical, and electrical properties of polymer composites. Biochar (BioC), in particular, is of interest for enhancing thermal and electrical conductivities in composites, and can potentially serve as a bio-derived graphitic carbon alternative for certain composite applications. In this work, we investigate a blended biopolymer system: PLA/PHBV, and addition of carbon black (CB), a commonly used functional filler as a comparison for Kraft lignin-derived BioC. We present calculations and experimental results for phase-separation and nanofiller phase affinity in this system, indicating that the CB localizes in the PHBV phase of the immiscible PHBV:PLA blends. The addition of BioC led to a deleterious reaction with the biopolymers, as indicated by blend morphology, differential scanning calorimetry showing significant melting peak reduction for the PLA phase, and a reduction in melt viscosity. For the CB nanofilled composites, electrical conductivity and dynamic mechanical analysis supported the ability to use phase separation in these blends to tune the percolation of mechanical and electrical properties, with a minimum percolation threshold found for the 80:20 blends of 1.6 wt.% CB. At 2% BioC (approximately the percolation threshold for CB), the 80:20 BioC nanocomposites had a resistance of 3.43x10 8 Omega as compared to 2.99x10 8 Omega for the CB, indicating that BioC could potentially perform comparably to CB as a conductive nanofiller if the processing challenges can be overcome. Investigations into alkaline and dealkaline lignin sources have shown that alkaline lignin experiences a significant effect on the thermal stability of PHBV eluding that alternate sources of lignin may provide a solution to the processing challenges mentioned. This work has helped to develop a understanding of the factors that aid in creating sustainable materials sourced from PLA,PHBV, and BioC.Item Permeability of three-strand electric fences by black bears and grizzly bears(Montana State University - Bozeman, College of Agriculture, 2018) Johnson, Brittani Justine; Chairperson, Graduate Committee: Lance McNewElectric fencing has been used to deter bears in North America for several decades. Producers have turned to a design of a minimum of five-wire electric fence as their primary solution to reduce livestock depredation and to reduce raids of chicken houses and beeyards. However, these designs are expensive and reducing the number of wires used in a design to three wires would be beneficial. Scientific evaluations of the efficacy of three-wire electric fencing at deterring bears is lacking. In 2015 and 2016, I conducted a study in the Blackfoot Valley of Montana to evaluate the efficacy of rapid-deployment electric fencing designs in deterring bears from baited enclosures. Baited enclosures of two fencing configurations were established at 20 sites in the study area. Each enclosure was systematically energized and unenergized for 3-day periods; and passage into the enclosure was monitored with trail cameras to provide information on effectiveness and permeability. I recorded 134 visits by bears to fenced enclosures during the study seasons of 2015 and 2016. Of these visits, 78 occurred in 2015 and included 57 black bears and 21 grizzly bears. Fifty-six visits occurred in 2016, including 34 black bears and 22 grizzly bears. Black bears and grizzly bears were successful at passing the short fence 48% (95% CI: 32.0 -- 63.6) and 23% (5.0 -- 53.8) of the time, respectively, when it was not energized. When the short fence was energized, black bears were 7% (0.2 -- 33.9) successful in passing, whereas grizzly bears were successful in 25% (5.5 -- 57.2) of attempts. When not energized, both species successfully passed the tall fence design in 58% (95% CI: 27.7 -- 84.8) of attempts. Black bears and grizzly bears successfully entered energized enclosures with tall fences in 30% (95% CI: 13.2 -- 52.9) and 0% (95% CI: 0.0 -- 45.9) of attempts, respectively. Both fence types deterred bears from entering baited enclosures and all fences allowed less than perfect access when unenergized, suggesting that even minimalistic configurations of electric fences may act as barriers to black and grizzly bears. Further study evaluating the effects of rapidly increasing construction of electric fencing is needed to assess landscape level effects on bear movement and habitat selection.Item Investigation of alternating components of earth potentials(Montana State University - Bozeman, College of Letters & Science, 1951) Farrand, Weston B.Item Lines of copper, tears of glass : the birth, growth and death of the Montana Power Company(Montana State University - Bozeman, College of Letters & Science, 2008) Johnson, Francis Joseph; Chairperson, Graduate Committee: Billy Smith.Montana Power collapsed amid images of TV reporters for Sixty Minutes chasing flustered Robert Gannon in Butte. The loss of two and a half billion dollars as well as the complete liquidation of thousands of shareholders created this Warhol moment for the firm's last president and Montana Power. Other dire consequences followed for the state: loss of Montana's only Fortune 500 firm, a doubling of utility bills and the loss of hundreds of jobs for the already depressed Butte area. Montana Power's importance transcends this slapstick "fifteen minutes" of fame moment at its demise. Montana Power became one of the few utilities to break from state price regulation during the deregulation mania of the 1990's. In a jarring development, the firm dissipated all its assets and dissolved shortly thereafter amidst a great deal of controversy. However, besides the failure of the firm after the heated deregulation battle, three other areas of the history of this utility proved pivotal in political, economic and environmental terms for not only the state, but also the rest of the West and the United States, as the events surrounding the Butte firm were often regional or national in scope and importance. First, the creation of the predecessors of the firm occurred at the very dawn of the electrical revolution at the turn of the nineteenth century. Powerful men and institutions from the Eastern United States set up the firm in a colonial-style environment and guided the development of the state. With the electricity revolution, dams, power lines, reservoirs, mills and logging operations appeared throughout the landscape. Second, the Great Depression produced an epic battle between public power advocates and trustbusters versus the Butte firm. The New Deal commenced building the Ft. Peck Dam and power stations, while working diligently to break up the utility trusts that included Montana Power. Third, lengthy car lines at gas pumps in the 1970's signaled the onset of the first energy crisis. The power company's attempt to generate energy using steam from coal mined in Eastern Montana set off a literal war with newly emergent environmental movement.