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Description
Within recent years, metal-organic frameworks, or MOF’s, have gained a lot of attention in the materials research community. These micro-porous materials are constructed of a metal oxide core and organic linkers, and have a wide-variety of applications due to their extensive material characteristic possibilities. The focus of this study is

Within recent years, metal-organic frameworks, or MOF’s, have gained a lot of attention in the materials research community. These micro-porous materials are constructed of a metal oxide core and organic linkers, and have a wide-variety of applications due to their extensive material characteristic possibilities. The focus of this study is the MOF-5 material, specifically its chemical stability in air. The MOF-5 material has a large pore size of 8 Å, and aperture sizes of 15 and 12 Å. The pore size, pore functionality, and physically stable structure makes MOF-5 a desirable material. MOF-5 holds applications in gas/liquid separation, catalysis, and gas storage. The main problem with the MOF-5 material, however, is its instability in atmospheric air. This inherent instability is due to the water in air binding to the zinc-oxide core, effectively changing the material and its structure. Because of this material weakness, the MOF-5 material is difficult to be utilized in industrial applications. Through the research efforts proposed by this study, the stability of the MOF-5 powder and membrane were studied. MOF-5 powder and a MOF-5 membrane were synthesized and characterized using XRD analysis. In an attempt to improve the stability of MOF-5 in air, methyl groups were added to the organic linker in order to hinder the interaction of water with the Zn4O core. This was done by replacing the terepthalic acid organic linker with 2,5-dimethyl terephthalic acid in the powder and membrane synthesis steps. The methyl-modified MOF-5 powder was found to be stable after several days of exposure to air while the MOF-5 powder exhibited significant crystalline change. The methyl-modified membrane was found to be unstable when synthesized using the same procedure as the MOF-5 membrane.
ContributorsAnderson, Anthony David (Author) / Lin, Jerry Y.S. (Thesis director) / Ibrahim, Amr (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
This project sought to analyze the effects of recycling Inconel 718 powder for Direct Metal Laser Sintering (DMSL) for additive manufacturing by testing low cycle fatigue tensile samples ranging from virgin to ten times recycled. Fracture generally occurs at the sample surface where persistent slip planes form and accumulate to

This project sought to analyze the effects of recycling Inconel 718 powder for Direct Metal Laser Sintering (DMSL) for additive manufacturing by testing low cycle fatigue tensile samples ranging from virgin to ten times recycled. Fracture generally occurs at the sample surface where persistent slip planes form and accumulate to cause a sudden fracture leading to signature markings for various phases of crack growth. Effects caused by contamination would be found in the first region of crack growth at the initiation site as the cause stress concentration. Tensile strength and fatigue life were compared to initiation site size found from fracture images obtained using scanning electron microscope imaging which found no significant deviations from the expected surface cracking and LCF region of slip plane buildups. Contamination was not found at any initiation site indicating that fracture life was not impacted by the amount of powder recycling. LCF life ranged from 60,000 to 250,000 which the majority experiencing fractures near 120,000 cyclic loadings. If defect effects were to be found than the low fatigue life sample would exhibit them however its fracture surface did not exhibit contamination but a slight increase in porosity found in the phase III cracking region. The In 718 powders were also analyzed to determine that the primary powder contaminates were brush fibers used to sweep away unused powders during processing however these were not seen in the final DMLS samples.
ContributorsLaws, Alec Ky (Author) / Tasooji, Amaneh (Thesis director) / Eylon, Daniel (Committee member) / Materials Science and Engineering Program (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description

This research aims to develop an understanding of how interventions designed to improve water quality in buildings can be used to mitigate Legionella pneumophila concentrations. Intervention methods can be described as any approach that can be used to improve microbial water quality. In order to provide a foundation of background

This research aims to develop an understanding of how interventions designed to improve water quality in buildings can be used to mitigate Legionella pneumophila concentrations. Intervention methods can be described as any approach that can be used to improve microbial water quality. In order to provide a foundation of background knowledge, a literature review was conducted to identify similar studies and collect relevant and timely research similar to the subject. The information gathered from the literature review was used to structure the sampling process and parameters. Using the research collected from the literature review, a review table was created to summarize the differences in the studies conducted and to determine research gaps. To categorize the studies, intervention methods, contaminants addressed, and water quality meta-data were differentiated for each of the articles. For the purpose of the sampling process, the three interventions analyzed consist of flushing, water heater set point change, and both flushing and water heater set point change. The locations of the sampling consisted of the city drinking water inlet, the basement janitor's closet, basement shower, 2nd floor, 3rd floor, and 7th floor break rooms and restrooms of the Interdisciplinary Science and Technology Building IV at ASU. For the flushing intervention, the sampling results demonstrated an increase in free and total chlorine concentration post flushing which aligns with the research found in the literature review. In addition, it was observed that iron concentrations drastically increased for both the cold and hot water by flushing. There was a significant decrease detected for ATP concentrations post flush in the hot line. However through the sampling session, the flushing intervention did not yield statistically significant results for Legionella concentrations.

ContributorsKotta, Vishnu Vardhan Reddy (Author) / Cahill, Molly (Co-author) / Call, Kathryn (Thesis director) / Johnson, Elizabeth (Committee member) / Barrett, The Honors College (Contributor) / The Design School (Contributor) / School of Sustainable Engineering & Built Envirnmt (Contributor)
Created2023-05