Master of Sciences (Engineering), Case Western Reserve University, 2025, Macromolecular Science and Engineering

Hexagonal boron nitride is a platelet-like thermally conductive filler commonly used to increase the thermal conductivity of polymers. Good alignment of boron nitride in the in-plane direction is required to create a good network for phonon transport to achieve high thermal conductivity in composite materials. To create good alignment of platelet-like particles, extensional flow is needed, like what is experienced by a polymer melt in a layer multiplication element in forced assembly co-extrusion. As a result, films with A/B structure of hBN + polymer/unfilled polymer were made using layer multiplication co-extrusion. The high degree of alignment and confinement of boron nitride into every other layer led to a higher-than-expected thermal conductivity at relatively low loadings of boron nitride. At only 12.7vol% (25wt%) filler loading, a composite film reached a thermal conductivity of 3.41 Wm-1K-1 which is much higher than was predicted by modeling.

Committee: Gary Wnek (Advisor); Gary Wnek (Committee Chair); Lei Zhu (Committee Member); Joao Maia (Committee Member); Svetlana Morozova (Committee Member) Subjects: Materials Science; Plastics

Master of Science, Miami University, 2022, Chemical, Paper and Biomedical Engineering

Hexagonal boron nitride (hBN) is a material recently discovered to exhibit surprising catalytic activity for the oxidative dehydrogenation of hydrocarbons. Previous studies indicate that redox sites can be produced on hBN, which suggests that hBN may also have potential in other oxidation reactions. In this work, hBN is instead tested as a catalyst and catalytic support for the oxidation of methanol over a temperature range of 210-360 °C. Methanol oxidation additionally reveals changes in surface active sites due to the formation of characteristic products for acid, basic, and redox active sites. Thermal treatment and sonication of hBN are demonstrated to have significant effects on conversion and product selectivity during methanol oxidation reactions. Dispersion of vanadium oxide on hBN yields increased redox activity and methanol conversion due to formation of VOx groups on the surface of hBN. The supported vanadium catalyst is shown to have superior performance when hBN is also exposed to thermal treatment and sonication. Raman, XRD, and FTIR studies are performed to characterize changes in the catalyst due to treatment or vanadium dispersion. Experiments are also performed to measure changes in active sites due to in situ functionalization of hBN during propane oxidation.

Committee: Keith Hohn (Advisor); Catherine Almquist (Committee Member); Jason Boock (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2004, Molecular, Cellular, and Developmental Biology

To understand the basis of axial specification and neural development, mouse models are commonly utilized. Bent tail (Bn) is a spontaneous mutation on the mouse X chromosome that produces tail deformities and open neural tube defects (NTDs). Analysis of progeny from an intraspecific backcross places the mutation between the microsatellites DXMit166 and DXMit140. Refined genetic and physical mapping of the Bn critical region demonstrate that the mutation is associated with a <170 kb submicroscopic deletion, including the entire Zic3 locus. Human mutations in ZIC3 are associated with left-right axis malformations. The presence of anal and spinal abnormalities in some patients and deletion of Zic3 in Bn mice support a key role for this gene in neural tube development and closure. However, mutations in the ZIC3 gene have yet to be identified in families with X-linked NTDs. Holoprosencephaly (HPE) results from abnormal development of the forebrain. One gene associated with HPE in humans, TG interacting factor (TGIF), was identified by its ability to bind to the retinoid X receptor response element, and has been shown to play a role in regulating TGF-β signaling. HPE is not evident in mice carrying the targeted null allele of Tgif. To elucidate whether Tgif in conjunction with reductions in TGF-β signaling can cause HPE, mice that have mutations in both Smad2 and Tgif were generated. Results show that of the Smad2+/-; Tgif+/- and Smad2+/-; Tgif-/- embryos, one third display HPE. Molecular characterization at E9.5 reveals that Shh, Fgf8, Six3 and Zic2 expression are not affected. The forebrain domain of Otx2 expression shows a modest to nearly complete reduction in affected embryos. Published data has shown that introduction of retinoic acid (RA) to cultured embryos or pregnant dams can induce HPE in embryos. Some of these studies have further shown a reduction in rostral Otx2 expression. The known interaction of Tgif and RA signaling led to the evaluation of the possibil (open full item for complete abstract)

Committee: Michael Weinstein (Advisor); Christine Beattie (Other); Heithem El Hodiri (Other); Amanda Simcox (Other) Subjects:

M.A. (Master of Arts in Liberal Studies), Ohio Dominican University, 2009, Liberal Studies

Through the lens of the fourteenth century manuscript Roman de Fauvel, BN 146, this inquiry explores a golden era of achievement in the late Middle Ages, with a particular focus on artistic and technical development in fourteenth century France. By using this manuscript as a focal po8int through which to examine crucial historical, political, and cultural events of late medieval France, the groundwork emerges for the great polyphonic achievements of fourteenth-century France. These technical and artistic developments, and their parallels with today's progressive technical age, provide insightful inspiration for contemporary life. Much as the medieval scholars looked to ancient Greece for philosophical insights and reasoning, so too, can twenty-first century persons look back to this golden medieval era to acquire additional self-knowledge and intellectual discernment. In this inquiry, the term polyphony becomes the connecting metaphor for the fourteenth century progressive complexities evolving in medieval manuscripts, music, art, and the social milieu. A crucial component leading to this era of achievement was the shift in focus, site, and production from the monastery to secular laypersons, along with the recognition of individual artistic achievement. The emergence of the guild system served to organize production, increase effective distribution, and allow for specialization. By looking at these cultural shifts through a discerning lens grounded in BN 146, an encompassing view comes into focus of a highly progressive, developing culture. The strengths of the monastery were its core, while the founding of universities created the immense need for dramatically increased manuscript production. Business and commerce generated record-keeping and specialization. Political factions and fractures in the Church hierarchy served to create multiple areas of artistic production along with political and religious centers. Meanwhile, the relative political stability in France (open full item for complete abstract)

Committee: Janette Knowles Ph.D. (Advisor); Jeremy Glazier M.F.A. (Other) Subjects:

Master of Science, University of Akron, 2005, Chemical Engineering

Synthesis and characterization of nanofibers is receiving a great deal of attention because of their potential as materials for nano-electronics. Surface energy plays an important role in understanding the wetting, adhesion and cohesion properties of materials. Synthesizing and effectively controlling the surface energy of nanomaterials, could highly improve their efficiency in different applications. This thesis is primarily focused on the surface energy characterization of uncoated and sputter coated nanofibers. The objectives include the extension of a proposed method in literature for calculating the surface energy of nanoparticles and preparation of optimal surface energy thin films of boron nitride (BN) on nanofibers.

Committee: Edward Evans (Advisor) Subjects: