ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- All Subjects: Environmental engineering
Methods are presented for characterizing contaminants in water (groundwater and surface waters) and indoor air. These techniques are integrative, providing information averaged over time and/or space, as opposed to instantaneous point measurements. Contaminants are concentrated from the environment, making these methods applicable to trace contaminants. These methods have the potential to complement existing techniques, providing the practitioner with opportunities to reduce costs and improve the quality of the data used in decision making.
A conceptual model for integrative sampling of environmental waters is developed and a literature review establishes an advantage in precision for active samplers. A programmable sampler was employed to measure the concentration of chromate in a shallow aquifer exhibiting time-dependent contaminant concentrations, providing a unique data set and sustainability benefits. The analysis of heat exchanger condensate, a waste stream generated by air conditioning, is demonstrated in a non-intrusive method for indoor air quality assessment. In sum, these studies present new opportunities for effective, sustainable environmental characterization.
The pore-scale characteristics of calcium carbonate precipitation via EICP and biogenic gas formation via MIDP were explored by visual observation in a transparent porous media using a microfluidic chip. For this purpose, an imaging system was designed and image processing algorithms were developed to analyze the experimental images and detect the nucleation and growth of precipitated minerals and formation and migration mechanisms of gas bubbles within the microfluidic chip. Statistical analysis was performed based on the processed images to assess the evolution of biomineral size distribution, the number of precipitated minerals and the porosity reduction in time. The resulting images from the biomineralization study were used in a numerical simulation to investigate the relation between the mineral distribution, porosity-permeability relationships and process efficiency. By comparing biogenic gas production with abiotic gas production experiments, it was found that the gas formation significantly affects the gas distribution and resulting degree of saturation. The experimental results and image analysis provide insight in the kinetics of the precipitation and gas formation processes and their resulting distribution and related engineering properties.