Harrington, George, Kilner, John, and Skinner, Stephen
Modified ionic transport at interfaces in oxide conductors has received significant interest recently, yet previous studies have provided inconsistent and often controversial results. Lattice strain occurring at heterogeneous interfaces or surrounding dislocations is often speculated as the cause for enhanced transport properties, yet direct evidence for this is lacking. The aim of this work was to investigate the possibility for modified oxygen conductivity at interfaces and develop a greater understanding of the underlying mechanisms. In this work, it was shown that the crystallographic orientation of yttria-stabilised zirconia (YSZ) films fabricated by pulsed laser deposition (PLD), could be altered by the roughness and the temperature of the substrate during deposition. Furthermore, the films were seen to feature an expanded out-of-plane lattice parameter, which was found to be dependent upon the deposition temperature, substrate, the orientation of film, and the thermal history after growth. The ionic transport of YSZ films fabricated on a range of substrates was assessed as a function of film thickness using electrochemical impedance spectroscopy (EIS) and a novel method of oxygen isotope exchange tracer diffusion (IETD). No enhancement over the conductivity of bulk YSZ was observed, despite expanded out-of-plane lattice parameters, substrates representing both positive and negative lattice mismatch, and a high density of interfacial dislocations. Instead, all interface regions were found to be more resistive due to a higher density of grain boundaries. Finally, gadolinia-doped ceria (CGO) films were analysed by low energy ion scattering (LEIS), to investigate the effects of dopant segregation to the surface and sub-surface regions. Gd segregation was found to occur for all films and observed to increase for higher annealing temperatures. Investigations into the affect of the lattice parameter on the rate of dopant segregation showed a possible link between segregation and lattice strain.
ProQuest LLC, Ph.D. Dissertation, Barry University. 236 pp.
Counselor Training, Metacognition, Attention, Graduate Students, Predictor Variables, Questionnaires, Age Differences, Cultural Awareness, Knowledge Level, and Counseling Techniques
The purpose of this research study was to assess levels of mindfulness-based skills in counselors-in-training at the masters and doctoral level. By examining mindfulness levels within the counselor-in-training population, a reference point was established among counseling students with predictors of mindfulness-based skill levels. The research design was a cross-sectional survey approach, using the "Five Facet Mindfulness Questionnaire" (Baer et al., 2006) paired with a researcher developed questionnaire. Results yielded significant differences among facets of mindfulness and independent variables of age, perceived multicultural competence, knowledge of mindfulness, hours of formal training, current practice of mindfulness, and frequency of practice. Length of mindfulness practice, hours of formal training, and age were significant predictors of total mindfulness scores for the counseling student sample. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]