Paper Competition Schedule:
All presentations will take place in BBW210
9 AM Gavin Yeung
9:30 AM Stephanie Richins
10 AM Daniel Cefus
10:30 AM Jacob Usrey
Presenter Abstracts:
Gavin Yeung, Colorado School of Mines
Combinatorial Synthesis of MgxZn1-xO thin films for use in CdTe solar cells
CdTe-based solar cells are the leading commercialized thin film photovoltaic technology with ~4% of total market share. This technology has achieved 22% record efficiency in recent years, but with the potential to exceed 30% there is significant room for further improvement. One strategy has been to replace the conventional CdS window layer with transparent alternatives. A leading candidate for this application is magnesium zinc oxide (MZO). In addition to being fully transparent to visible light, the band gap maybe tuned by adjusting the magnesium content, which allows one to optimize efficiency by controlling the conduction band alignment with the CdTe absorber. High efficiency devices have been reported using MZO, but questions remain about its optimal composition, sensitivity to subsequent processing, and stability. To date previous studies have produced MZO thin films by sputtering in an argon ambient using oxide targets, which limits exploration to discrete compositions. In this study we developed approaches for combinatorial synthesis of MZO libraries through reactive sputtering and integrated them into CdTe solar cells. An advantage of this approach is that it employs metal targets, which are low cost and offer higher deposition rates. In this work we first established conditions for controllable synthesis of the binary oxides (MgO and ZnO), and then formed ternary combinatorial libraries. Intrinsic film quality was assessed using a variety of techniques including XRD, UV-visible spectrophotometry, spectroscopic ellipsometry, and Kelvin probe. It was found that the thickness and composition of the MZO libraries could be well-described based on superposition of the individual oxide rates. Libraries provide a band gap variation more than 0.5 eV across a 3-inch substrate, which can improve the precision of identifying the optimal composition since subsequent device processing is identical. These superstrates were used for CdTe device fabrication. Optimal devices were achieved with MZO having a band gap of ~3.5 eV, which is lower than values typically reported (~3.7 eV). In this talk, we will discuss the reasons for these differences.
Stephanie Richins, New Mexico State University
Ag Decorated FeCo Core-frame Nanocubes for Gas Sensing
The growing concern over hazardous gasses in the environment has led to a demand for cheaper and more effective gas sensors. Seniconducting sensors have recently gained popularity due to their small size, low cost, and improved sensing capabilities. In this work Ag-FeCo nanocubes were investigated as gas sensors. The nanoparticales were synthesized using magnetron sputtering. The particles were deposited on a silicon wafer where lithography was perfomed. HRTEM with SAED was used to characterize the structure of the sample. The Ag-FeCo showed promising gas sensing capabilities.
Daniel Cerfus, South Dakota School of Mines
Detection of the Inhibitors Furfural, 5-Hydroxymethylfurfural (HMF), and Corresponding Metabolites Produced by Saccharomyces cerevisiae D5A During Aerobic and Anaerobic Batch Fermentation
Previous research has shown the dilute acid pre-treatment of pine wood produces inhibitors (furfural and 5-hydroxymethylfurfural) that decrease specific cell growth rate and ethanol productivity during subsequent fermentation. Yeast strains that are able to metabolize these inhibitors have been shown to produce different metabolites, forming 2,5-Furandimethanol (FDM) and furfuryl alcohol under anerobic conditions or 5-Hydroxy-2-furancarboxylic acid (HFC) and 2-furoic acid under aerobic conditions. The goal of this study was to determine whether the yeast strain D5A produces these same metabolites under microaeration vs anaerobic conditions. It was found under the anaerobic conditions of sealed serum bottles, detectable amounts of FDM and furfuryl alcohol were produced from HMF and furfural, respectively. HFC and 2-furoic acid were similarly produced in aerobic batches grown in shake flasks. These additional aerobic pathways may partially explain why furfural and HMF are metabolized faster under microaeration (-150 mV redox potential) conditions (0.25 g furfural/L/OD/hr vs 0.13 g furfural/OD/hr for anaerobic fermentation). Faster furfural and HMF metabolism ultimately leads to greater ethanol productivity with microaeration (1.32 g ethanol/L/hr vs. 0.51 g ethanol/L/hr for anaerobic fermentation).
Jacob Usrey, New Mexico State University
Hydrothermal Liquefaction of Food Waste
Food waste-derived biofuels can offer “free” energy by capturing what consumers don’t utilize in the kitchen and dining room, and turning that waste into bio-crude oil. Since most food waste contains a significant fraction of water, hydrothermal liquefaction (HTL) is a promising method for converting the waste into usable product in the form of bio-crude oil. HTL uses subcritical water (270°C-350°C and 8-18MPa) as both a solvent and reaction medium to convert complex organic matter into energy-rich bio-crude oil. This oil can be further refined into liquid fuels similar to gasoline, diesel, and jet fuel. In this study, two samples of food waste from the on-campus Sodexo Food Services: pre-consumer waste (kitchen scraps such as lettuce leaves, carrot peelings, potato peelings, etc.) and post-consumer waste, (everything that is left over). The waste materials were converted by HTL under various conditions. Batch HTL conversion experiments were carried out using a 100mL autoclave reactor at reaction temperatures and retention times of 245°C-290°C and 0-30 minutes, respectively. Yields of bio-crude oil and higher heating value (HHV) energy content were compared to determine the optimal condition for conversion. Yields of bio-crude oil and char ranged from 15-27% and 21-33% for post-consumption food waste respectively. The average HHV is 30.1 MJ/kg which is similar to anthracite coal. Further laboratory analyses are being carried out to fully characterize the HTL products.
All presentations will take place in BBW210
9 AM Gavin Yeung
9:30 AM Stephanie Richins
10 AM Daniel Cefus
10:30 AM Jacob Usrey
Presenter Abstracts:
Gavin Yeung, Colorado School of Mines
Combinatorial Synthesis of MgxZn1-xO thin films for use in CdTe solar cells
CdTe-based solar cells are the leading commercialized thin film photovoltaic technology with ~4% of total market share. This technology has achieved 22% record efficiency in recent years, but with the potential to exceed 30% there is significant room for further improvement. One strategy has been to replace the conventional CdS window layer with transparent alternatives. A leading candidate for this application is magnesium zinc oxide (MZO). In addition to being fully transparent to visible light, the band gap maybe tuned by adjusting the magnesium content, which allows one to optimize efficiency by controlling the conduction band alignment with the CdTe absorber. High efficiency devices have been reported using MZO, but questions remain about its optimal composition, sensitivity to subsequent processing, and stability. To date previous studies have produced MZO thin films by sputtering in an argon ambient using oxide targets, which limits exploration to discrete compositions. In this study we developed approaches for combinatorial synthesis of MZO libraries through reactive sputtering and integrated them into CdTe solar cells. An advantage of this approach is that it employs metal targets, which are low cost and offer higher deposition rates. In this work we first established conditions for controllable synthesis of the binary oxides (MgO and ZnO), and then formed ternary combinatorial libraries. Intrinsic film quality was assessed using a variety of techniques including XRD, UV-visible spectrophotometry, spectroscopic ellipsometry, and Kelvin probe. It was found that the thickness and composition of the MZO libraries could be well-described based on superposition of the individual oxide rates. Libraries provide a band gap variation more than 0.5 eV across a 3-inch substrate, which can improve the precision of identifying the optimal composition since subsequent device processing is identical. These superstrates were used for CdTe device fabrication. Optimal devices were achieved with MZO having a band gap of ~3.5 eV, which is lower than values typically reported (~3.7 eV). In this talk, we will discuss the reasons for these differences.
Stephanie Richins, New Mexico State University
Ag Decorated FeCo Core-frame Nanocubes for Gas Sensing
The growing concern over hazardous gasses in the environment has led to a demand for cheaper and more effective gas sensors. Seniconducting sensors have recently gained popularity due to their small size, low cost, and improved sensing capabilities. In this work Ag-FeCo nanocubes were investigated as gas sensors. The nanoparticales were synthesized using magnetron sputtering. The particles were deposited on a silicon wafer where lithography was perfomed. HRTEM with SAED was used to characterize the structure of the sample. The Ag-FeCo showed promising gas sensing capabilities.
Daniel Cerfus, South Dakota School of Mines
Detection of the Inhibitors Furfural, 5-Hydroxymethylfurfural (HMF), and Corresponding Metabolites Produced by Saccharomyces cerevisiae D5A During Aerobic and Anaerobic Batch Fermentation
Previous research has shown the dilute acid pre-treatment of pine wood produces inhibitors (furfural and 5-hydroxymethylfurfural) that decrease specific cell growth rate and ethanol productivity during subsequent fermentation. Yeast strains that are able to metabolize these inhibitors have been shown to produce different metabolites, forming 2,5-Furandimethanol (FDM) and furfuryl alcohol under anerobic conditions or 5-Hydroxy-2-furancarboxylic acid (HFC) and 2-furoic acid under aerobic conditions. The goal of this study was to determine whether the yeast strain D5A produces these same metabolites under microaeration vs anaerobic conditions. It was found under the anaerobic conditions of sealed serum bottles, detectable amounts of FDM and furfuryl alcohol were produced from HMF and furfural, respectively. HFC and 2-furoic acid were similarly produced in aerobic batches grown in shake flasks. These additional aerobic pathways may partially explain why furfural and HMF are metabolized faster under microaeration (-150 mV redox potential) conditions (0.25 g furfural/L/OD/hr vs 0.13 g furfural/OD/hr for anaerobic fermentation). Faster furfural and HMF metabolism ultimately leads to greater ethanol productivity with microaeration (1.32 g ethanol/L/hr vs. 0.51 g ethanol/L/hr for anaerobic fermentation).
Jacob Usrey, New Mexico State University
Hydrothermal Liquefaction of Food Waste
Food waste-derived biofuels can offer “free” energy by capturing what consumers don’t utilize in the kitchen and dining room, and turning that waste into bio-crude oil. Since most food waste contains a significant fraction of water, hydrothermal liquefaction (HTL) is a promising method for converting the waste into usable product in the form of bio-crude oil. HTL uses subcritical water (270°C-350°C and 8-18MPa) as both a solvent and reaction medium to convert complex organic matter into energy-rich bio-crude oil. This oil can be further refined into liquid fuels similar to gasoline, diesel, and jet fuel. In this study, two samples of food waste from the on-campus Sodexo Food Services: pre-consumer waste (kitchen scraps such as lettuce leaves, carrot peelings, potato peelings, etc.) and post-consumer waste, (everything that is left over). The waste materials were converted by HTL under various conditions. Batch HTL conversion experiments were carried out using a 100mL autoclave reactor at reaction temperatures and retention times of 245°C-290°C and 0-30 minutes, respectively. Yields of bio-crude oil and higher heating value (HHV) energy content were compared to determine the optimal condition for conversion. Yields of bio-crude oil and char ranged from 15-27% and 21-33% for post-consumption food waste respectively. The average HHV is 30.1 MJ/kg which is similar to anthracite coal. Further laboratory analyses are being carried out to fully characterize the HTL products.
Rules
1. Each entry must be an undergraduate student and a member of one of the participating student chapters. Others may present, but cannot be considered for the top prize.
2. Based on individual chapter interest, chapters may be required to nominate a limited number of participants (TBA based on interest from all chapters)
3. Co-authorship of papers is permitted. However, only one person shall make the presentation at the Regional Student Paper Competition, and this person must have been substantially involved in the project or subject of the presented paper.
4. A panel of three chemical engineers (faculty, industry representative, or AIChE local section member) will judge paper presentations. The decision of these judges will be final.
5. The time limit will be 15 minutes for presentation and 3-5 minutes for Q&A.
6. First, second, and third place will receive cash prizes and first place will earn the right to present at the Annual Student Conference Competition.
1. Each entry must be an undergraduate student and a member of one of the participating student chapters. Others may present, but cannot be considered for the top prize.
2. Based on individual chapter interest, chapters may be required to nominate a limited number of participants (TBA based on interest from all chapters)
3. Co-authorship of papers is permitted. However, only one person shall make the presentation at the Regional Student Paper Competition, and this person must have been substantially involved in the project or subject of the presented paper.
4. A panel of three chemical engineers (faculty, industry representative, or AIChE local section member) will judge paper presentations. The decision of these judges will be final.
5. The time limit will be 15 minutes for presentation and 3-5 minutes for Q&A.
6. First, second, and third place will receive cash prizes and first place will earn the right to present at the Annual Student Conference Competition.