Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item STUDENTS’ ACHIEVEMENT EMOTIONS IN CHINESE CHEMISTRY CLASSROOMS(2017) Gong, Xiaoyang; Ketelhut, Diane Jass; Education Policy, and Leadership; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Achievement emotions are critical for students’ academic performance and career choices. The previous literature has focused on one specific type of achievement emotions – test anxiety – in Western contexts and neglected other various emotions experienced in different occasions such as attending classes. The present study aims to address the research gap by examining students’ achievement emotions in a specific cultural and subject context – Chinese high school chemistry classrooms. Subjects were 103 16 or 17-year-old eleventh-grade students (45 female and 58 male) from two chemistry classes in the same high school in China. The qualitative and quantitative data was collected from four sources: pre- and post- surveys, open-response questions, classroom observations and teacher/student interviews. This dissertation examined Chinese students’ achievement emotions from both theoretical and practical perspectives. First, it theoretically investigated the dimensions of Chinese students’ achievement emotions in traditional chemistry classrooms and how these dimensions were related to its antecedent (i.e., chemistry self-efficacy) and effect (i.e., classroom engagement). The factor analysis indicated two distinct factors emerged from Chinese students’ emotions: positive emotions and shame (one specific type of negative emotions). The structural equation modeling showed that both chemistry self-efficacy and positive emotions were significant and positive predictors of students’ classroom engagement. Chemistry self-efficacy also significantly and positively predicted students’ positive emotions while predicting students’ perceptions of shame negatively. However, the path from shame to classroom engagement was not significant after controlling for positive emotions. Second, it practically explored how one specific pedagogical strategy of integrating the computer simulation – a visualization tool to review content knowledge – influenced students’ perceptions of achievement emotions and related affective variables (i.e., chemistry self-efficacy and engagement). Independent sample t-tests showed that the computer simulation significantly increased students’ chemistry self-efficacy beliefs and positive emotions. In contrast, its effects on negative emotions and classroom engagement were not significant. By scrutinizing qualitative data from different sources, I provided explanations for the computer simulation’s role in influencing the above four affective variables.Item Numerical studies of constraints and gravitational wave extraction in general relativity(2004-08-04) Fiske, David Robert; Misner, Charles W; Physics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Within classical physics, general relativity is the theory of gravity. Its equations are non-linear partial differential equations for which relatively few closed form solutions are known. Because of the growing observational need for solutions representing gravitational waves from astrophysically plausible sources, a subfield of general relativity, numerical relativity, has a emerged with the goal of generating numerical solutions to the Einstein equations. This dissertation focuses on two fundamental problems in modern numerical relativity: (1) Creating a theoretical treatment of the constraints in the presence of constraint-violating numerical errors, and (2) Designing and implementing an algorithm to compute the spherical harmonic decomposition of radiation quantities for comparison with observation. On the issue of the constraints, I present a novel and generic procedure for incorporating the constraints into the equations of motion of the theory in a way designed to make the constraint hypersurface an attractor of the evolution. In principle, the prescription generates non-linear corrections for the Einstein equations. The dissertation presents numerical evidence that the correction terms do work in the case of two formulations of the Maxwell equations and two formulations of the linearized Einstein equations. On the issue of radiation extraction, I provide the first in-depth analysis of a novel algorithm, due originally to Misner, for computing spherical harmonic components on a cubic grid. I compute explicitly how the truncation error in the algorithm depends on its various parameters, and I also provide a detailed analysis showing how to implement the method on grids in which explicit symmetries are enforced via boundary conditions. Finally, I verify these error estimates and symmetry arguments with a numerical study using a solution of the linearized Einstein equations known as a Teukolsky wave. The algorithm performs well and the estimates prove true both in simulations run on a uniform grid and in simulations that make use of fixed mesh refinement techniques.