The University of Tulsa has a long history in energy-related research, including both traditional and alternative energy.  In this REU research area, undergraduate students will have the opportunity to conduct research in model-assisted energy decision making, especially as they pertain to solar energy and biofuel production.  Specifically, we hypothesize that computational fluid dynamics (CFD) simulations will capture fluid and nutrient flows in various solar and biofuel production techniques in a way that will guide future experimental studies.  For solar energy, an insolation model of energy availability will be coupled with a fluid flow and heat transfer algorithm for predicting energy production in various solar configurations.  For biofuels research, CFD techniques are coupled with optimization routines to find the best combination of design and operating conditions that will yield the most economical production of biofuels, especially those that are algae-derived.

Several million gallons of water are treated daily for fracturing, injection, disposal and reuse operations during oil and gas production.  The use of fresh water sources for fracturing operations is discouraged.  Fortunately, over the past decade, the oil and gas industry is making an enormous effort to recycle and re-use produced water from onshore and offshore operations and to use alternate water sources for well operations.  Produced water can contain 500-180,000 mg/L of dissolved solids concentration compared to fresh water (<500 mg/L).  Therefore, it is often times necessary to reduce salinity of these waters prior to reuse or recycle.

Current desalination technologies are divided mainly into two categories: thermal and membrane techniques.  The traditional desalination plants based on the multi-stage flash (MSF) distillation and reverse osmosis (RO) processes are reliable and established processes [10] – [11], but they are energy intensive. The energy cost of supplying the projected global water need with present technologies is high – especially in a carbon-constrained world. Overall, there are still opportunities to develop water treatment technologies to process produced water at a large scale with a focus on minimizing energy costs and maximizing water recovery. Recently, hydrate-based desalination (HBD) has been proposed for seawater desalination. The advantage of HBD process is that it is less energy intensive as it operates at temperatures well above the normal freezing point of water [12]. The limitation of slow kinetics can be overcome through the prudent choice of favorable guest gas/liquid, promotor addition, and improved reactor designs. The hypothesis is that the chemistry of promotors is the important factor in increasing the kinetic rate of hydrate formation and decomposition.

Objectives:

• to operate hydrate reactor, differential scanning calorimeter and high temperature gas chromatography
• to analyze thermodynamic and kinetic data for hydrate process
  S. A. Kalogirou, “Seawater desalination using renewable-energy-sources,” Progress in Energy and Combustion Science, vol. 31, pp. 242 – 281, 2005.A. D. Khawaji, I. K. Kutubkhanah and J.-M. Wie, “Advances in seawater desalination technologies,” Desalination, vol. 221, pp. 47 – 69, 2008.A. J. Barduhn, H. E. Towlson and Y. C. Hu, “The properties of some new gas hydrates and their use in demineralizing sea water,” AIChE Journal, vol. 8, no. 2, pp. 176 – 183, 1962.

Recently, theoretical calculations have shown that by stacking a perovskite solar cell on a conventional solar cell made of Si or Copper Indium Gallium Diselenide (CIGS) cell can produce a tandem solar cell that can extend the efficiency beyond the fundamental limit of maximum efficiency of 30% predicted by the Shockley-Queisser limit. The main advantage of the perovskite structure when used in a tandem cell design with Si or CIGS solar cell is that we can continuously tune the composition of the precursor solutions of perovskites to vary the bandgap of this material, thereby selectively absorbing the solar wavelength most suitable for Si or CIGS. Bandgap tuning, for optimizing the conversion efficiency, can be tested by a wide range of compositional parameters in perovskites. Fabricating and testing various thin films with different compositional variations is costly and time consuming. In this study we propose a simple and cost-effective method for testing and designing perovskite-Si and perovskite-CIGS tandem cells using microfluidic channels There is a significant cost reduction compared to thin film deposition by a factor of 10. In addition, micro channels will protect the perovskite precursor solutions from moisture, ambient temperature and oxidation. Another advantage of a PDMS microchannel design is that we can design patterns on the PDMS backside and focus the light from the perovskite precursor solutions in micro channels on a Si or CIGS cell. We will explore mixtures with different compositions in micro channels to tune the bandgap and control the rate at which precursor solutions are combined to form the final stable product.

With growing interest into origin of life studies as well as the advancement of medical research using nanostructured architectures, investigations into amino acid interactions have increased heavily in the field of surface science. Amino acid assembly on metallic surfaces is typically investigated with Scanning Tunneling Microscopy (STM) at low temperatures (LT) and under ultra-high vacuum (UHV), which can achieve the necessary resolution to study detailed molecular interactions and chiral templating. However, in only studying these systems at LT and UHV, results often tend to be uncertain when moving to more relevant temperatures and pressures. This investigation focuses on the Electrochemical STM (EC-STM) study of five simple amino acids (L-Valine, L-threonine, L-Isoleucine, L-Phenylalanine, and L-Tyrosine) as well as two modifications of a single amino acid (L-Isoleucine Ethyl Ester and N-Boc-L-Isoleucine), and the means by which these molecules interact with a Au(111) surface. By analyzing the results gathered via EC-STM at ambient conditions, fundamental insight can be gained into not only the behavior of these amino acids with varied side chains and the underlying surface, but also into the relevance of LT-UHV STM data as it compares to data taken in more realistic scenarios (1,2). This project will lead to a deeper understanding of how small, prebiotic molecules interact with surfaces and participate in the emergence of biologically applicable precursors. On a fundamental level, this project will study how amino acid molecules interact and how those interactions correlate to biologically relevant structures like proteins.

• Using EC-STM to Obtain an Understanding of Amino Acid Adsorption on Au(111). Jesse A. Phillips, Kennedy P. Boyd*, Irene Baljak*, Lauren K. Harville*, Erin V. Iski. AIP Advances, 9, (2019), 105221-105233.
• Formation of Magic Gold Fingers Under Mild and Relevant Experimental Conditions. Jesse A. Phillips, Kennedy P. Boyd*, Irene Baljak*, Lauren K. Harville*, Erin V. Iski. Sci., 687, (2019), 1-6.

A new approach for assembling and integrating multi-gene pathways into the nuclear genome of microalgae using CRISPR-Cas9 [16] is the focus of this project, which will study the assembly and integration of complex multi-gene biosynthetic pathways into the nuclear genome of the microalgae species Chlamydomonas reinhardtii.  The potential of algae-based biofuels [17] and protein therapeutics [18] is well documented, but in order to achieve its full potential, genetic engineering is needed to increase the production of target metabolites to desirable levels. Although recombinant protein expression in the microalgae has recently become more robust, the assembly and expression of complex multi-gene biosynthetic pathways in microalgae has yet to be fully accomplished and is a significant step in our ability to engineer microalgae metabolite production for the production of commercially important products [19], [20]. Thus we hypothesize that based on the successful development of similar methods in other species, an efficient nuclear multi-gene assembly and integration method can be developed co C. reinhardtii.  Biosynthetic pathways consisting of one to four genes will be assembled using homologous recombination in the yeast strain Saccharomyces cerevisiae and integrated into the C. reinhardtii nuclear genome using CRISPR-Cas9.  Multi-gene biosynthetic pathways of increasing complexity will be studied systematically. Pathways to be assembled include well studied selection markers and reporter genes and the biosynthetic pathway for the bioplastic polyhydroxybutyrate (PHB) [21]. Once integrated into the nucleus, the genetically engineered strains will be tested using a variety of methods to determine the levels of gene expression and the production level of PHB. The proposed project will provide important insights into the assembly and expression of biosynthetic pathways in microalgae and result in the development of an important tool for genetically modifying the nuclear genome of C. reinhardtii. These insights and the resulting methodology will aid current efforts to produce biofuels from microalgae, enhance our ability to produce therapeutic proteins in microalgae, and be an effective new tool for genetically engineering higher plants and other strains of microalgae.

Methods and technologies related to renewable energies are rapidly improving. Because renewable energy resources are abundant and practically unlimited, they are attracting more attention in the energy production industry. Implementing and taking advantage of such technologies requires a comprehensive feasibility study in each region to determine which sources and to what degree are available to utilize. Then, a reliable power source can be designed for the region of interest. One of the sustainable energy resources is solar energy. In this project, the feasibility of utilizing solar energy for power generation in Tulsa region will be investigated by means of parabolic troughs experimental facility available at The University of Tulsa. The results of this project will be used to validate a model that will be developed to predict the potential for energy extraction from local renewable resources.

While the cost of solar panels continues to decrease, the weight and rigidity of currently available devices limits the number and location of these systems. In this project we aim to utilize flexible and lightweight electrode materials to address these challenges. Additionally, we are evaluating electrochemical processes for depositing the photoactive materials on these devices to further improve the practical production of these inexpensive solar cells.

Elastocaloric materials are solids with a pronounced coupling between temperature and mechanical deformation, due to the latent heat of a solid-to-solid phase transformation (akin to the latent heat of the phase change between ice and water). When an elastocaloric is repeatedly pushed and pulled, it can be used as a solid-state refrigerator, with the potential for significant energy savings. Since these materials are mechanically cycled, it is important to know how they respond to cracks. However, the solid-to-solid phase change in the materials complicates their cracking response, and the crack growth response of these materials has only been characterized for a select few temperature points, instead of the wide range of temperatures that they experience. Using a unique thermomechanical capability that is being developed at TU, this work will seek insights about the behavior of cracks in elastocaloric materials while they undergo repeated mechanical loads across a wide range of temperatures. 

In 2004, graphene took the scientific community by surprise when UK researchers discovered its remarkable properties even though it is only one-atom thick. It conducts electricity better than any common substance and is 100 times stronger than steel.  Its potential application include membranes for water purification, composites, and coatings, in batteries for energy storage, microprocessors, sensors etc. As of now, graphene is made by mechanically splitting strongly layered materials like graphite into individual atomic planes, by chemical exfoliation or through chemical vapor deposition (CVD) of hydrocarbon gases on transition metals.  However, all these methods have limitations: mechanical exfoliation is hard to scale-up and is tedious, the chemical method uses harsh acids and not all graphene oxide can be reduced to graphene while CVD uses vacuum and H₂ with mostly hydrocarbon vapors as carbon source.  In this research a solid renewable material is used to grow graphene without vacuum and without H₂.  More specifically, biochar, a solid carbon-rich material from biomass model compounds (cellulose and lignin) produced by hydrothermal carbonization (200-350ºC), is used as the raw material. The uniqueness of this approach is that it does not require vacuum nor hydrogen as in the case of CVD to form graphene on metal foils. Our reactor is a simple quartz tube heated in a tube furnace. The metal foils also do not require any pretreatment (like removal of oxides with H₂) prior to graphene synthesis. This research will involve the synthesis and analysis of the graphene so produced in an effort to optimize the process.  Analytical tools such as Scanning Electron Microscope (SEM) (to see the surface morphology), X-Ray diffraction (XRD) (to characterize the crystalline structure of the foil and graphene), X-Ray Photoelectron spectroscopy (XPS) (to characterize the surface composition of the foils after graphene synthesis), and Raman spectroscopy (to characterize the synthesized graphene on the foils) may be used.

This project aims at fabricating carbon-carbon composites as potential alternatives to metallic systems used in gas-phase Concentrating Solar Power (CSP) collectors.  C-C composites have extreme resistance to high temperatures and maintain mechanical properties with little change from room temperature up to almost 1800 °C and have high thermal conductivity.  This research will entail in preparing different prepregs (carbon fibers with resin with different number of layers and layering direction) and carbonizing and densifying these prepregs at different heating rates to achieve more efficient heat transfer and mechanical durability.

Mineral, or ore, flotation is a separation technology used to selectively separate different minerals found in a mined ore sample before it is sent to be refined into metals. This separation process makes the mining of mixed ores economically feasible and less energy intensive. The process works by mixing ground ore particles with water to form a slurry. Certain ‘collector’ molecules are then added to the slurry to render the desired minerals more hydrophobic than others. The slurry is then added to the flotation tanks, which are aerated to produce bubbles. The hydrophobic particles attach to the surface of these air bubbles, which rise to the surface and form froth or foam layer. The froth is then removed from the cell producing a more concentrated stream of the desired mineral. This same separation technique is also used in waste water treatment and paper recycling to separate desirable products from undesirable or remove difficult to process materials from the stream. A large number of specialty chemicals have been developed to render different minerals hydrophobic, but many of these have undesirable environmental impacts. Developing and testing sustainable alternatives to these chemicals is necessary to ensure that ore processing can continue into the future and ensure that the metals necessary for modern electronics and other devices can be mined sustainably.