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Description
Ethanol is a widely used biofuel in the United States that is typically produced through the fermentation of biomass feedstocks. Demand for ethanol has grown significantly from 2000 to 2015 chiefly due to a desire to increase energy independence and reduce the emissions of greenhouse gases associated with transportation. As demand grows, new ethanol plants must be developed in order for supply to meet demand. This report covers some of the major considerations in developing these new plants such as the type of biomass used, feed treatment process, and product separation and investigates their effect on the economic viability and environmental benefits of the ethanol produced. The dry grind process for producing ethanol from corn, the most common method of production, is examined in greater detail. Analysis indicates that this process currently has the highest capacity for production and profitability but limited effect on greenhouse gas emissions compared to less common alternatives.
ContributorsSchrilla, John Paul (Author) / Kashiwagi, Dean (Thesis director) / Kashiwagi, Jacob (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
Tri-layer lithium ion battery separators were synthesized by dip-coating macroporous YSZ and mesoporous sol-gel derived gamma-alumina films onto porous polypropylene. These separators were installed into coin-cell lithium ion batteries and subjected to charge/discharge cycle testing to determine specific capacity. The gamma-alumina coated separators exhibited low capacity, while the YSZ coated separators failed immediately. Investigation by SEM and a surface wettability test indicated that the gamma alumina and YSZ coatings exhibited low wettability, and the YSZ coating exhibited low porosity. These factors resulted in high internal resistance of the battery, due to electrolyte failing to permeate the separator and provide transport of lithium ions between the electrodes.
ContributorsMcafee, Paul Milton (Author) / Lin, Jerry Y.S. (Thesis director) / Kasik, Alexandra (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
Capnography is the monitoring of concentrations of carbon dioxide in exhaled breath. It allows reliable insight into patients' metabolism, ventilation, and blood circulation. Capnography has become an integral part of anesthesiology monitoring in operating rooms. However, its used is limited in other contexts due to deeply engrained protocols, size of capnographs, and the complexity of its interpretation. Intensive care units and in-home use could greatly benefit by a widespread usage of capnographs. Measuring methods include infrared spectroscopy, mass spectroscopy, and chemical colorimetric analysis. Infrared technology is currently the most widely used and cost-effective method for measuring carbon dioxide. However, this device can be bulky and costly. A novel portable breath CO2 analyzer was developed for this purpose. The analyzer features an accurate colorimetric CO2 sensor that can analyze ETCO2 in real time. Many advancements have been in made in the sensor fabrication process. Nevertheless, research on optimal packaging conditions and accelerated aging times have been limited. In this experiment, carbon dioxide sensors were packaged at four different environmental conditions to test their long-term stability. This was done to determine if these conditions had an effect on sensor degradation. In the second part of the experiment, a separate batch of sensors was placed inside an oven at 48 oC to investigate the effect of stabilization temperature dependence and accelerated aging. In conclusion, the data obtained from the sensors packaged at different conditions could not be concluded to be statistically different. Sensors packaged at ambient conditions had the highest average value at 0.45030 V and the ones at controlled 33% humidity had the lowest at 0.39348 V. The sensors packaged at 8.25% CO2 had the smallest variance in their voltage measurements. From these data, it can be concluded that environmental testing conditions had the greatest effect on the measured signal. The oven experiment showed that sensors rapidly stabilize at high temperature and these stay constant after reaching this stabilization. For future work, the signal difference at different environmental conditions should be done. Control of environmental conditions can be achieved by building a glove box to control temperature and humidity.
ContributorsCorral Clayton, Javier Alfonso (Author) / Forzani, Erica (Thesis director) / Tsow, Tsing (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2015-05
Description
Depletion of fossil fuel resources has led to the investigation of alternate feedstocks for and methods of chemical synthesis, in particular the use of E. coli biocatalysts to produce fine commodity chemicals from renewable glucose sources. Production of phenol, 2-phenylethanol, and styrene was investigated, in particular the limitation in yield and accumulation that results from high product toxicity. This paper examines two methods of product toxicity mitigation: the use of efflux pumps and the separation of pathways which produce less toxic intermediates. A library of 43 efflux pumps from various organisms were screened for their potential to confer resistance to phenol, 2-phenylethanol, and styrene on an E. coli host. A pump sourced from P. putida was found to allow for increased host growth in the presence of styrene as compared to a cell with no efflux pump. The separation of styrene producing pathway was also investigated. Cells capable of performing the first and latter halves of the synthesis were allowed to grow separately and later combined in order to capitalize on the relatively lower toxicity of the intermediate, trans-cinnamate. The styrene production and yield from this separated set of cultures was compared to that resulting from the growth of cells containing the full set of styrene synthesis genes. Results from this experiment were inconclusive.
ContributorsLallmamode, Noor Atiya Jabeen (Author) / Nielsen, David (Thesis director) / Cadillo-Quiroz, Hinsby (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Iodide-based ionic liquids have been widely employed as sources of iodide in electrolytes for applications utilizing the triiodide/iodide redox couple. While adding a low-viscosity solvent such as water to ionic liquids can greatly enhance their usefulness, mixtures of highly viscous iodide-containing ILs with water have never been studied. Thus, this paper investigates, for the first time, mixtures of water and the ionic liquid 1-butyl-3-methylimidazolium iodide ([BMIM][I]) through a combined experimental and molecular dynamics study. The density, melting point, viscosity and conductivity of these mixtures were measured experimentally. The composition region below 50% water by mole was found to be dramatically different from the region above 50% water, with trends in density and melting point differing before and after that point. Water was found to have a profound effect on viscosity and conductivity of the IL, and the effect of hydrogen bonding was discussed. Molecular dynamics simulations representing the same mixture compositions were performed. Molecular ordering was observed, as were changes in this ordering corresponding to water content. Molecular ordering was related to the experimentally measured mixture properties, providing a possible explanation for the two distinct composition regions identified by experiment.
ContributorsNgan, Miranda L (Author) / Dai, Lenore (Thesis director) / Nofen, Elizabeth (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
Increased investigation into the development of macromolecular fluorophores has resulted in the synthesis and discovery of several potential candidates. These include modified and polymeric based dendritic structures, hyperbranched polymers and linear polymers. Strong inherent blue photoluminescence has been recently described in linear polyamine polymers in the absence of any chemical modifications. Here we describe the screening of amine/polyamine compounds for inherent photoluminescence. Several compounds that exhibited strong inherent blue photoluminescence following excitation with UV light were identified. Furthermore we demonstrated successful synthesis of poly(amino ether) polymers as well as chemically cross-linked poly(amino ether) thermosets with the lead Pentaethylenehexamine which was found to have strong inherent blue photoluminescence. The polymers and thermosets were found to retain the photoluminescent properties of the original lead compound. The polymers and thermosets were investigated for their ability to sequester heavy metals from aqueous solutions. An increased decrease in initial photoluminescence was observed as the materials were incubated with increasing metal salt concentration as a result of metal binding sequestration. The poly(amino ether) polymers were found to have higher sensitivity for metal sequestration when compared to equivalent amount of linear 25 kDa polyethylenimine. The strong inherent blue photoluminescence and the ease of synthesis of the poly(amino ether) polymers and thermosets give these materials strong potential for future applications as sensors.
ContributorsVu, Jeffrey (Co-author) / Ramos, James (Co-author) / Rege, Kaushal (Thesis director) / Godeshala, Sudakhar (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
In this thesis, glycan nodes, the basic subunits of complex biological sugars, were studied to determine the reproducibility of gas chromatography-mass spectrometry (GC/MS) based methylation analysis of whole blood plasma by normalization using an internal standard of heavy permethylated glycans. Glycans are complex biological sugars that have a variety of applications in the human body and will display aberrant compositions when produced by cancerous cells. Thus an assay to determine their composition can be used as a diagnostic tool. It was shown that the assay may have potential use, but needs further refinement to become an improvement over current methods by analyzing the results of ratio-determination and replicate experiments.
ContributorsMiyasaki, Tyler Takeo (Author) / Borges, Chad (Thesis director) / Van Horn, Wade (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
In our modern world the source of for many chemicals is to acquire and refine oil. This process is becoming an expensive to the environment and to human health. Alternative processes for acquiring the final product have been developed but still need work. One product that is valuable is butanol. The normal process for butanol production is very intensive but there is a method to produce butanol from bacteria. This process is better because it is more environmentally safe than using oil. One problem however is that when the bacteria produce too much butanol it reaches the toxicity limit and stops the production of butanol. In order to keep butanol from reaching the toxicity limit an adsorbent is used to remove the butanol without harming the bacteria. The adsorbent is a mesoporous carbon powder that allows the butanol to be adsorbed on it. This thesis explores different designs for a magnetic separation process to extract the carbon powder from the culture.
ContributorsChabra, Rohin (Author) / Nielsen, David (Thesis director) / Torres, Cesar (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
Calcium hydroxide carbonation processes were studied to investigate the potential for abiotic soil improvement. Different mixtures of common soil constituents such as sand, clay, and granite were mixed with a calcium hydroxide slurry and carbonated at approximately 860 psi. While the carbonation was successful and calcite formation was strong on sample exteriors, a 4 mm passivating boundary layer effect was observed, impeding the carbonation process at the center. XRD analysis was used to characterize the extent of carbonation, indicating extremely poor carbonation and therefore CO2 penetration inside the visible boundary. The depth of the passivating layer was found to be independent of both time and choice of aggregate. Less than adequate strength was developed in carbonated trials due to formation of small, weakly-connected crystals, shown with SEM analysis. Additional research, especially in situ analysis with thermogravimetric analysis would be useful to determine the causation of poor carbonation performance. This technology has great potential to substitute for certain Portland cement applications if these issues can be addressed.
ContributorsHermens, Stephen Edward (Author) / Bearat, Hamdallah (Thesis director) / Dai, Lenore (Committee member) / Mobasher, Barzin (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
Animation is a medium that is not taken as seriously as live-action television and film. This thesis focuses on the representation of LGBT characters in American animation and attempts to give a rigorous analysis on a medium that should be taken seriously. Analysis is done on the stereotypes and coding from various animated shows, such as South Park, Family Guy, and Steven Universe. The shows are further divided into adult and children's animation, in which the analysis will track how LGBT characters are represented and have progressed in both. The thesis describes how problematic these characters may potentially be and how the images may project certain cultural and social attitudes towards the LGBT community. The thesis also considers the future of queer visibility and representation in other mediums, other than just in broadcast television. It was found that representation begins in the early 90s in adult comedy animation with Big Gay Al in South Park. In adult animation, the focus is usually more on the use of stereotypes and how these stereotypes are used for comedy. These stereotypes are sometimes enforced or subverted, depending on the show. It was also found that in adult animation, there has been a shift towards normalizing queer characters to fit a heteronormative framework. For children's animation, the sexuality of a character is subtler and coded with context clues. Some children and teen shows have decided to reveal the sexuality of certain characters in the last episode of the series. Children's animation also follows a similar trend that adult animation has taken with the normalization of queer characters.
ContributorsVuong, Hansen (Author) / Dove-Viebahn, Aviva (Thesis director) / Bryant, Jason (Committee member) / Chemical Engineering Program (Contributor) / School of Film, Dance and Theatre (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05