Matching Items (22)
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- All Subjects: Sustainability
- All Subjects: Materials
- Creators: Chemical Engineering Program
Description
Solid oxide fuel cells have become a promising candidate in the development of high-density clean energy sources for the rapidly increasing demands in energy and global sustainability. In order to understand more about solid oxide fuel cells, the important step is to understand how to model heterogeneous materials. Heterogeneous materials are abundant in nature and also created in various processes. The diverse properties exhibited by these materials result from their complex microstructures, which also make it hard to model the material. Microstructure modeling and reconstruction on a meso-scale level is needed in order to produce heterogeneous models without having to shave and image every slice of the physical material, which is a destructive and irreversible process. Yeong and Torquato [1] introduced a stochastic optimization technique that enables the generation of a model of the material with the use of correlation functions. Spatial correlation functions of each of the various phases within the heterogeneous structure are collected from a two-dimensional micrograph representing a slice of a solid oxide fuel cell through computational means. The assumption is that two-dimensional images contain key structural information representative of the associated full three-dimensional microstructure. The collected spatial correlation functions, a combination of one-point and two-point correlation functions are then outputted and are representative of the material. In the reconstruction process, the characteristic two-point correlation functions is then inputted through a series of computational modeling codes and software to generate a three-dimensional visual model that is statistically similar to that of the original two-dimensional micrograph. Furthermore, parameters of temperature cooling stages and number of pixel exchanges per temperature stage are utilized and altered accordingly to observe which parameters has a higher impact on the reconstruction results. Stochastic optimization techniques to produce three-dimensional visual models from two-dimensional micrographs are therefore a statistically reliable method to understanding heterogeneous materials.
ContributorsPhan, Richard Dylan (Author) / Jiao, Yang (Thesis director) / Ren, Yi (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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 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
Description
Based on theoretical calculations, a material that is highly transmissive below 3000 nm and opaque above 3000 nm is desired to replace glass covers for flat plate solar thermal systems. Additionally, a suitable replacement material needs to have a sufficiently high operating temperature in order to prevent the glazing from melting and warping in a solar system. Traditional solar thermal applications use conventional soda lime glass or low iron content glass to accomplish this; however, this project aims to investigate acrylic, polycarbonate, and FEP film as suitable alternatives for conventional solar glazings. While UV-Vis and FT-IR spectroscopy indicate that these polymer substitutes may not be ideal when used alone, when used in combination with coatings and additives, these materials may present an opportunity for a glazing replacement. A model representing a flat plate solar collector was developed to qualitatively analyze the various materials and their performance. Using gathered spectroscopy data, the model was developed for a multi-glazing system and it was found that polymer substitutes could perform better in certain system configurations. To complete the model, the model must be verified using empirical data and coatings and additives investigated for the purposes of achieving the desired materials optical specifications.
ContributorsBessant, Justin Zachary (Author) / Friesen, Cody (Thesis director) / Lorzel, Heath (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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
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
Currently, approximately 40% of the world’s electricity is generated from coal and coal power plants are one of the major sources of greenhouse gases accounting for a third of all CO2 emissions. The Integrated Gasification Combined Cycle (IGCC) has been shown to provide an increase in plant efficiency compared to traditional coal-based power generation processes resulting in a reduction of greenhouse gas emissions. The goal of this project was to analyze the performance of a new SNDC ceramic-carbonate dual-phase membrane for CO2 separation. The chemical formula for the SNDC-carbonate membrane was Sm0.075Nd0.075Ce0.85O1.925. This project also focused on the use of this membrane for pre-combustion CO2 capture coupled with a water gas shift (WGS) reaction for a 1000 MW power plant. The addition of this membrane to the traditional IGCC process provides a purer H2 stream for combustion in the gas turbine and results in lower operating costs and increased efficiencies for the plant. At 900 °C the CO2 flux and permeance of the SNDC-carbonate membrane were 0.65 mL/cm2•min and 1.0×10-7 mol/m2•s•Pa, respectively. Detailed in this report are the following: background regarding CO2 separation membranes and IGCC power plants, SNDC tubular membrane preparation and characterization, IGCC with membrane reactor plant design, process heat and mass balance, and plant cost estimations.
ContributorsDunteman, Nicholas Powell (Author) / Lin, Jerry (Thesis director) / Dong, Xueliang (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-05
Description
A growing number of stylists \u2014 cosmetologists \u2014 are finding it harder to afford the basic necessities such as rent. However, the ever-increasing presence of smartphones and the increasing need for on-demand services like Uber and Uber Eats creates a unique opportunity for stylists \u2014 Clippr. Clippr is an application that aims to connect individual stylists directly to their customers. The application gives stylists a platform to create and display their own prices, services, and portfolio. Customers get the benefit of finding a stylist that suits them and booking instantly. This project outlines the backend for the Clippr application. It goes over the framework, REST API, and various functionalities of the application. Additionally, the project also covers the work that is still needed to successfully launch the application.
ContributorsKamath, Sanketh (Author) / Olsen, Christopher (Thesis director) / Sebold, Brent (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
p-Coumaric acid is used in the food, pharmaceutical, and cosmetic industries due to its versatile properties. While prevalent in nature, harvesting the compound from natural sources is inefficient, requiring large quantities of producing crops and numerous extraction and purification steps. Thus, the large-scale production of the compound is both difficult and costly. This research aims to produce p-coumarate directly from renewable and sustainable glucose using a co-culture of Yeast and E. Coli. Methods used in this study include: designing optimal media for mixed-species microbial growth, genetically engineering both strains to build the production pathway with maximum yield, and analyzing the presence of p-Coumarate and its pathway intermediates using High Performance Liquid Chromatography (HPLC). To date, the results of this project include successful integration of C4H activity into the yeast strain BY4741 ∆FDC1, yielding a strain that completely consumed trans-cinnamate (initial concentration of 50 mg/L) and produced ~56 mg/L p-coumarate, a resting cell assay of the co-culture that produced 0.23 mM p-coumarate from an initial L-Phenylalanine concentration of 1.14 mM, and toxicity tests that confirmed the toxicity of trans-cinnamate to yeast for concentrations above ~50 mg/L. The hope for this project is to create a feasible method for producing p-Coumarate sustainably.
ContributorsJohnson, Kaleigh Lynnae (Author) / Nielsen, David (Thesis director) / Thompson, Brian (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
In the pursuit of sustainable sources of energy that do less harm to the environment, numerous technologies have been developed to reduce carbon emissions in the atmosphere. The implementation of carbon capture and storage systems (CCS) has played a crucial role in reducing CO2 emissions, but depleting storage reserves and ever-increasing costs of sequestrating captured CO2 has prompted the idea of utilizing CO2 as soon as it is produced (i.e. carbon capture and utilization, or CCU) and storing any remaining amounts. This project analyzes the cost of implementing a delafossite CuFeO2 backed CCU system for the average US coal-burning power plant with respect to current amounts of CO2 captured. Beyond comparing annual maintenance costs of CCU and CCS systems, the project extends previous work done on direct CO2 conversion to liquid hydrocarbons by providing a protocol for determining how the presence of NO affects the products formed during pure CO2 hydrogenation. Overall, the goal is to gauge the applicability of CCU systems to power plants with a sub 10-year lifespan left, whilst observing the potential revenue that can be potentially generated from CCU implementation. Under current energy costs ($0.12 per kWh), a delafossite CuFeO2 supported CCU system would generate over $729 thousand in profit for an average sized supercritical pulverized coal power (SCPC) plants selling diesel fuel created from CO2 hydrogenation. This amount far exceeds the cost of storing captured CO2 and suggests that CCU systems can be profitable for SCPC power plants that intend to burn coal until 2025.
ContributorsShongwe, Thembelihle Wakhile (Author) / Andino, Jean (Thesis director) / Otsengue, Thonya (Committee member) / Economics Program in CLAS (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Polymer modified tuning fork-based sensors were fabricated to assure reproducibility. The effect of system valve switching on the modified tuning fork-based sensors was studied at the different temperature. The response to Xylene gas sample on stabilized modified tuning fork-based sensors with temperature was defined while learning about the key analytical performance for chemical sensors to be used in the real-world application.
ContributorsRohit, Riddhi S (Author) / Forzani, Erica (Thesis director) / Tsow, Francis (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05