Matching Items (3)
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- All Subjects: Enzymes
- Creators: Kavazanjian, Edward
Description
The public has expressed a growing desire for more sustainable and green technologies to be implemented in society. Bio-cementation is a method of soil improvement that satisfies this demand for sustainable and green technology. Bio-cementation can be performed by using microbes or free enzymes which precipitate carbonate within the treated soil. These methods are referred to as microbial induced carbonate precipitation (MICP) and enzyme induced carbonate precipitation (EICP). The precipitation of carbonate is the formation of crystalline minerals that fill the void spaces within a body of soil.
This thesis investigates the application of EICP in a soil collected from the Arizona State University Polytechnic campus. The surficial soil in the region is known to be a clayey sand. Both EICP and MICP have their limitations in soils consisting of a significant percentage of fines. Fine-grained soils have a greater surface area which requires the precipitation of a greater amount of carbonate to increase the soil’s strength. EICP was chosen due to not requiring any living organisms during the application, having a faster reaction rate and size constraints.
To determine the effectiveness of EICP as a method of improving a soil with a significant amount of fines, multiple comparisons were made: 1) The soil’s strength was analyzed on its own, untreated; 2) The soil was treated with EICP to determine if bio-cementation can strengthen the soil; 3) The soil had sand added to reduce the fines content and was treated with EICP to determine how the fines percentage effects the strength of a soil when treated with EICP.
While the EICP treatment increased the strength of the soil by over 3-fold, the strength was still relatively low when compared to results of other case studies treating sandy soils. More research could be done with triaxial testing due to the samples of the Polytechnic soil’s strength coming from capillarity.
This thesis investigates the application of EICP in a soil collected from the Arizona State University Polytechnic campus. The surficial soil in the region is known to be a clayey sand. Both EICP and MICP have their limitations in soils consisting of a significant percentage of fines. Fine-grained soils have a greater surface area which requires the precipitation of a greater amount of carbonate to increase the soil’s strength. EICP was chosen due to not requiring any living organisms during the application, having a faster reaction rate and size constraints.
To determine the effectiveness of EICP as a method of improving a soil with a significant amount of fines, multiple comparisons were made: 1) The soil’s strength was analyzed on its own, untreated; 2) The soil was treated with EICP to determine if bio-cementation can strengthen the soil; 3) The soil had sand added to reduce the fines content and was treated with EICP to determine how the fines percentage effects the strength of a soil when treated with EICP.
While the EICP treatment increased the strength of the soil by over 3-fold, the strength was still relatively low when compared to results of other case studies treating sandy soils. More research could be done with triaxial testing due to the samples of the Polytechnic soil’s strength coming from capillarity.
ContributorsRoss, Johnathan (Author) / Kavazanjian, Edward (Thesis advisor) / Zapata, Claudia (Committee member) / Hamdan, Nasser (Committee member) / Arizona State University (Publisher)
Created2018
Description
This dissertation investigates the potential for enzyme induced carbonate cementation as an alternative to Portland cement for creating building material from sand aggregate. We create a solution of urease enzyme, calcium chloride (CaCl2), and urea in water and added sand. The urease catalyzes the synthesis of carbonate from urea, and the carbonate then bonds with a dissociated calcium ion and precipitates from the solution as calcium carbonate (CaCO3). This precipitate can form small crystal bridges at contacts between sand grains that lock the sand grains in place. Using enzyme induced carbonate precipitation we created a cemented sand sample with a maximum compressive strength of 319 kPa and an elastic modulus of approximately 10 MPa. Images from the SEM showed that a major failure mechanism in the cemented samples was the delamination of the CaCO3 from the sand grains. We observed that CaCO3 cementation did not when solutions with high concentrations of CaCl2 and urea were used.
ContributorsBull, Michael Ryan (Author) / Kavazanjian, Edward (Thesis director) / Chawla, Nikhilesh (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor)
Created2014-05
Description
The two chapters of this thesis focus on different aspects of DNA and the properties of nucleic acids as the whole. Chapter 1 focuses on the structure of DNA and its relationship to enzymatic efficiency. Chapter 2 centers itself on threose nucleic acid and optimization of a step in the path to its synthesis. While Chapter 1 discusses DNA and Uracil-DNA Glycosylase with regards to the base excision repair pathway, Chapter 2 focuses on chemical synthesis of an intermediate in the pathway to the synthesis of TNA, an analogous structure with a different saccharide in the sugar-phosphate backbone.
Chapter 1 covers the research under Dr. Levitus. Four oligonucleotides were reacted for zero, five, and thirty minutes with uracil-DNA glycosylase and subsequent addition of piperidine. These oligonucleotides were chosen based on their torsional rigidities as predicted by past research and predictions. The objective was to better understand the relationship between the sequence of DNA surrounding the incorrect base and the enzyme’s ability to remove said base in order to prepare the DNA for the next step of the base excision repair pathway. The first pair of oligonucleotides showed no statistically significant difference in enzymatic efficiency with p values of 0.24 and 0.42, while the second pair had a p value of 0.01 at the five-minute reaction. The second pair is currently being researched at different reaction times to determine at what point the enzyme seems to equilibrate and react semi-equally with all sequences of DNA.
Chapter 2 covers the research conducted under Dr. Chaput. Along the TNA synthesis pathway, the nitrogenous base must be added to the threofuranose sugar. The objective was to optimize the original protocol of Vorbrüggen glycosylation and determine if there were better conditions for the synthesis of the preferred regioisomer. This research showed that toluene and ortho-xylene were more preferable as solvents than the original anhydrous acetonitrile, as the amount of preferred isomer product far outweighed the amount of side product formed, as well as improving total yield overall. The anhydrous acetonitrile reaction had a final yield of 60.61% while the ortho-xylene system had a final yield of 94.66%, an increase of approximately 32%. The crude ratio of preferred isomer to side product was also improved, as it went from 18% undesired in anhydrous acetonitrile to 4% undesired in ortho-xylene, both values normalized to the preferred regioisomer.
Chapter 1 covers the research under Dr. Levitus. Four oligonucleotides were reacted for zero, five, and thirty minutes with uracil-DNA glycosylase and subsequent addition of piperidine. These oligonucleotides were chosen based on their torsional rigidities as predicted by past research and predictions. The objective was to better understand the relationship between the sequence of DNA surrounding the incorrect base and the enzyme’s ability to remove said base in order to prepare the DNA for the next step of the base excision repair pathway. The first pair of oligonucleotides showed no statistically significant difference in enzymatic efficiency with p values of 0.24 and 0.42, while the second pair had a p value of 0.01 at the five-minute reaction. The second pair is currently being researched at different reaction times to determine at what point the enzyme seems to equilibrate and react semi-equally with all sequences of DNA.
Chapter 2 covers the research conducted under Dr. Chaput. Along the TNA synthesis pathway, the nitrogenous base must be added to the threofuranose sugar. The objective was to optimize the original protocol of Vorbrüggen glycosylation and determine if there were better conditions for the synthesis of the preferred regioisomer. This research showed that toluene and ortho-xylene were more preferable as solvents than the original anhydrous acetonitrile, as the amount of preferred isomer product far outweighed the amount of side product formed, as well as improving total yield overall. The anhydrous acetonitrile reaction had a final yield of 60.61% while the ortho-xylene system had a final yield of 94.66%, an increase of approximately 32%. The crude ratio of preferred isomer to side product was also improved, as it went from 18% undesired in anhydrous acetonitrile to 4% undesired in ortho-xylene, both values normalized to the preferred regioisomer.
ContributorsTamirisa, Ritika Sai (Author) / Levitus, Marcia (Thesis director) / Stephanopoulos, Nicholas (Committee member) / Windman, Todd (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05