Electrocatalysis of anodic oxygen-transfer reactions at modified lead dioxide electrodes

This dissertation describes results of the studies of anodic oxygen-transfer reactions at the electrochemically deposited lead dioxide electrodes modified by incorporation of spatially separated catalytic sites at the electrode surface. These active surface sites were created either by co-depositing the PbO[subscript]2 films with dopants (i.e., Bi[superscript]3+, As[superscript]5+, Cl[superscript]- and OAc[superscript]-) or by oxidative electrosorption of Bi[superscript]3+ at the pre-deposited oxide films to produce the Bi[superscript]5+-adsorbed PbO[subscript]2. The incorporated cations and anions were speculated to substitute for the surface Pb[superscript]4+ and O[superscript]2- ions, respectively;Studies showed that the dopants influence (i) the deposition kinetics, (ii) the electrocatalytic properties, (iii) the surface morphologies, and (iv) the preferential orientations of the exposed crystallite planes of the doped oxides, as studied by cyclic voltammetry, scanning electron microscopy (SEM), and X-ray diffraction spectrometry (XRD). Results obtained from X-ray fluorescence spectrometry (XRF) revealed that the electrode activity was related to the densities of dopants in the modified electrodes, which were controlled by the concentration ratio of (dopant) / (Pb[superscript]2+) in the deposition solutions;The anion-doped PbO[subscript]2 electrodes exhibited significant catalytic activities for anodic O-transfer reactions for numerous compounds in 1 M H[subscript]2SO[subscript]4 when compared with that in 1 M HClO[subscript]4. The HSO[subscript]4[superscript]- ions were concluded to be adsorbed at the electrode surface by an ion-exchange mechanism with the exchangeable anions at the electrode surface (i.e., Cl[superscript]- for Cl-PbO[subscript]2 and OAc[superscript]- for OAc-PbO[subscript]2). Investigations of mass changes at electrode surface resulting from the anion exchange were performed using an Electrochemical Quartz Crystal Microbalance (EQCM);Catalytic production of adsorbed hydroxyl radicals ([superscript].OH[subscript] ad) was concluded to be a prerequisite for an O-transfer reaction as well as the O[subscript]2 evolution process. Enhanced rates of O[subscript]2 evolution were observed at modified PbO[subscript]2 electrodes, which suggested a catalyzed mechanism for the anodic discharge of H[subscript]2O to form the adsorbed OH radicals. This reaction was concluded to be the rate-limiting step for both O-transfer and O[subscript]2-evolution processes

The Culturally Responsive Teacher Preparedness Scale: An Exploratory Study

The purpose of this study was to investigate the competencies of culturally responsive teaching and construct a Culturally Responsive Teacher Preparedness Scale (CRTPS) for the use of teacher preparation programs and preservice teachers. Competencies listed in the scale were identified through literature reviews and input from experts. The preparedness scale was created through an exploratory factor analysis. According to the factor analysis, there were three factors for CRTPS: curriculum and instruction, relationship and expectation establishment, and group belonging formation. The scale is well supported by psychometric analysis including factor loadings, internal consistency, and testing fairness with gender and race. Limitations and conclusions were made for the use of this scale

The Impacts of Climate Change on the Gulf of Maine Northern Shrimp (Pandalus borealis) Distribution, Reproduction, and Life

The Gulf of Maine northern shrimp (Pandalus borealis) once supported a significant winter fishery for the Gulf of Maine (GOM). Although the shrimp fishery is not comparable to the lobster business, it provided fishermen and many coastal communities jobs and incomes in winters after lobster seasons. However, a moratorium has been put on the shrimp fishery since 2014 due to record low population abundance and perceived recruitment failures. The recruitment failures have been correlated with warming water temperatures over the past decade. The GOM has been recognized as experiencing rapid warming as a result of global climate change. Uncertain impacts of the changing environment on the life cycle and the fishery of northern shrimp could hamper the efforts to rebuild a resilient and sustainable shrimp fishery. Consequently, there is a pressing need to understand the impacts of climate change on the life cycle and population dynamics of the GOM northern shrimp. The objectives of this research project are to 1) develop a cost-effective sampling protocol for building a comprehensive fecundity database including maternal body size, and number and size of eggs; 2) examine the impacts of climate-induced environmental variabilities on egg mortality; 3) develop a complete size-fecundity relationship in order to derive a robust estimate of reproductive potential of the population; 4) illuminate the effect of water temperature on spatial structure for each life stage; and 5) investigate the relationship between environmental variabilities and habitat suitability in northern shrimp spawners’ distribution. The findings reveal that the GOM bottom temperatures might have changed considerably over the past fifty years; however, the correlation between water temperature and parasitic infection eggs was not significant and the changes in reproductive potential might be related to population density rather than bottom temperature. The results also showed that the distributions of mature groups were getting patchier and shifting northward, which were correlated with declined population abundance and warming temperature, respectively. Furthermore, the quality of habitat has declined significantly for mature groups in summer and fall, especially in the 2010s, which could result from warming temperature and subsequently lead to declined spawning stock biomass

The 'Landscape Character Turn': An Examination of Experience in the UK and Taiwan

Landscape policy in the UK has a tradition of conserving natural beauty within designated areas. As a result of both the progressive development of landscape analysis techniques, of which the most recent is the use of Landscape Character Assessment (LCA), and contemporary environmental trends, landscape policy in the past twenty years has undergone a significant �landscape character turn� from this focus on the 'best' landscapes to the wider notion of the 'rest'�of the landscape. This poses a particular challenge for the non-statutory locally defined landscape designations. Over time questions have arisen about whether these designations should be retained or replaced by criteria-based policies informed by LCA and covering the countryside as a whole. The 'turn' underlines significant changes in landscape concepts and the way in which they contribute to planning policies and practice in the UK and also at a global scale. This research explores how the character-based approach has, in the last two decades, developed into an alternative tool to the traditional local landscape designation approach. The evolution of these two approaches has been examined at both the national (England) level and the local level (English local authorities) by conducting policy document review, case study analysis and in-depth interviews. At the national level, the discourses concerning the transition between the two approaches have been extracted to scrutinise their development and interrelationships. At the local level, three sample local authorities have been identified to investigate how the approaches have been delivered. Lastly, the research examines the extent to which knowledge gained from the UK experience can be compared to the cultural context of Taiwan, where the use of local landscape designations is still prevailing. The research shows that the character-based approach is appropriate to replace the use of local landscape designations given that certain conditions are met. Outside the UK this approach is not readily application to other planning contexts where crucial elements for carrying out this approach are absent

Learning Vocabulary Through Assisted Repeated Reading: How Much Time Should There Be Between Repetitions of the Same Text?

Repeated reading, which involves the reading of short passages several times, has been demonstrated to be beneficial for second language fluency (Chang & Millett, 2013) and vocabulary acquisition (Liu & Todd, 2014). Despite the increasing interest in repeated reading, no study has addressed the effects of time distribution how different encounters with the same text should be spaced for repeated reading to have the strongest impact on second language learning, specifically on vocabulary acquisition, the focus of the present study. This study includes two groups of 16-year-old EFL learners in Taiwan (n = 71). One group carried out assisted repeated reading (i.e., with audio support) once every day for five consecutive days (intensive distribution); the other read the same text once every week for five consecutive weeks (spaced distribution). Our results revealed that intensive practice led to more immediate vocabulary gains but spaced practice led to greater long-term retention