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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Emotional Experience During Couple Support Interactions: The Role of Attachment Anxiety and Avoidance

Lachmar, E. Megan 01 December 2017 (has links)
The Marriage and Family Therapy clinic at Utah State University conducted a study called the Relationship Checkup in which couple data was collected in an initial 2-hour session and feedback was provided for them in a follow-up 1-hour session. This checkup included completing self-report surveys, having an in-person interview, as well as couple interactions. The current study was carried out within the context of this broader relationship checkup, focusing on the couple support interactions, in which partners discussed a personal issue they would like to change about themselves. Although a substantial amount of attention has been given to the role of attachment during couple conflict, much less attention has been given to social support processes. Yet the purpose of therapy is not only to diminish disruptive conflict but also to enhance positive relationship processes, making a greater understanding of social support processes crucial to the therapy process. The results of this study indicate that partners with higher levels of avoidant attachment perceived they were receiving and providing less support. This reveals that couple therapists may need to assist these partners in reaching out and providing support. Additionally, results show that for women, discussing a personal issue soothed them physiologically. Therefore, rather than focusing on couple conflict, couples therapists can also build positive relationship interactions through couple social support.
2

Tuning the Morphology and Electronic Properties of Single-Crystal LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4-δ</sub>

Spence, Stephanie L. 27 October 2020 (has links)
The commercialization of lithium-ion batteries has played a pivotal role in the development of consumer electronics and electric vehicles. In recent years, much research has focused on the development and modification of the active materials of electrodes to obtain higher energies for a broader range of applications. High voltage spinel materials including LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4-δ</sub> (LNMO) have been considered as promising cathode materials to address the increasing demands for improved battery performance due to their high operating potential, high energy density, and stable cycling lifetimes. In an effort to elucidate fundamental structure-property relationships, this thesis explores the tunable properties of single-crystal LNMO. Utilizing facile molten salt synthesis methods, the structural and electronic properties of LNMO can be well controlled. Chapter 2 of this thesis focuses on uncovering the effect of molten salt synthesis parameters including molten salt composition and synthetic temperature on the materials properties. A range of imaging, microscopic, and spectroscopic techniques are used to characterize structural and electronic properties which are investigated in tandem with electrochemical performance. Results indicate the Mn oxidation state is highly dependent on synthesis temperature and can dictate performance, while the molten salt composition strongly influences the particle morphology. In Chapter 3, we explore the concept of utilizing LNMO as a tunable support for heterogeneous metal nanocatalysts, where alteration of the support structure and electronics can have an influence on catalytic properties due to unique support effects. Ultimately, this work illustrates the tunable nature of single-crystal LNMO and can inform the rational design of LNMO materials for energy applications. / M.S. / The development of lithium-ion batteries has been fundamental to the expansion and prevalence of consumer electronics and electric vehicles in the twenty-first century. Despite their ubiquity, there is an ongoing drive by researchers to address the limitations and improve the quality and performance of lithium ion batteries. Much research has focused on altering the composition, structure, or properties of electrodes at the materials level to design higher achieving batteries. A fundamental understanding of how composition and structure effect battery performance is necessary to progress toward better materials. This thesis focuses on investigating the properties of LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4-δ</sub> (LNMO). LNMO material is considered a promising cathode material to meet the increasing consumer demands for improved battery performance. Through the synthesis methods, the shape of individual particles and the global electronic properties of LNMO can be tuned. In this work, specific synthesis parameters are systematically tuned and the properties of the resultant LNMO materials are explored. Electrochemical testing also evaluates the performance of the materials and offers insights into how they may fair in real battery systems. In an effort to potentially recycle spent battery materials, LNMO is also utilized as a catalyst support. Alteration of shape and electronic properties of the LNMO support can influence the catalytic properties, or the ability of the material to enhance the rate of a chemical reaction. Overall, this thesis explores how LNMO can be tuned and utilized for different applications. This work provides insights for understanding LNMO properties and direction for the development of future battery materials.

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