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El Paso, TX, United States

Hepp A.F.,NASA | Kulis M.J.,NASA | Psarras P.C.,Cleveland State University | Ball D.W.,Cleveland State University | And 8 more authors.
7th Symposium on Space Resource Utilization | Year: 2014

Transportation fuels production (including aerospace propellants) from non-traditional sources (gases, waste materials, and biomass) has been an active area of research and development for decades. Reducing terrestrial waste streams simultaneous with energy conversion, plentiful biomass, new low-cost methane sources, and/or extra-terrestrial resource harvesting and utilization present significant technological and business opportunities being realized by a new generation of visionary entrepreneurs. We examine several new approaches to catalyst fabrication and new processing technologies to enable utilization of these non-traditional raw materials. Two basic processing architectures are considered: a single-stage pyrolysis approach that seeks to basically re-cycle hydrocarbons with minimal net chemistry or a two-step paradigm that involves production of supply or synthesis gas (mainly carbon oxides and hydrogen) followed by production of fuel(s) via Sabatier or methanation reactions and/or Fischer-Tröpsch synthesis. Optimizing the fraction of product stream relevant to targeted aerospace (and other transportation) fuels via modeling, catalyst fabrication and novel reactor design are described. Energy utilization is a concern for production of fuels for either terrestrial or space operations; renewable sources based on solar energy and/or energy efficient processes may be mission enabling. Another important issue is minimizing impurities in the product stream(s), especially those potentially posing risks to personnel or operations through (catalyst) poisoning or (equipment) damage. Technologies being developed to remove (and/or recycle) heteroatom impurities are briefly discussed as well as the development of chemically robust catalysts whose activity are not diminished during operation. The potential impacts on future missions by such new approaches as well as balance of system issues are addressed. Source


Ahmed M.K.,Georgia Southern University | Choudhuri A.,500 iversity Ave | Rahman M.,Georgia Southern University
50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition | Year: 2012

Due to the abundant nature of hydrocarbon fuels, combustion of methane is very promising in the field of micro-combustion. In the current research, the channel type meso-combustors made of copper have been chosen to investigate the flame dynamics and the stability of a methane flame in different operating and geometric conditions. The combustors that have been investigated are as follows: a 20-mm 3-inlet, a 40-mm 3-inlet, and a 40-mm 5-inlet. Hydrogen-assisted methane flames and methane flames with pure oxygen are presented in the current research. It has been found that the methane flame cannot sustain with air as an oxidizer in the meso-combustor for a non-premixed mixture. The combustion of hydrogen-assisted methane combustion can be achieved for a very narrow range of mass flow rates and a very narrow range of overall equivalence ratios. For a hydrogen-assisted flame the stability of the 20-mm combustor is the lowest among all the combustors. The premixed methane-air-hydrogen with air as the oxidizer was found to be more stable than the other combustors. The 40-mm 3-inlet combustor was found to have improved stability compared to the 20-mm 3-inlet combustor. The ratio of hydrogen to methane is the key factor that controls the stability in this case of hydrogen-assisted methane combustion. The higher the ratio is, the higher the stability is for a given mass flow rate. The flame stability increases significantly when instead of air, O2 is used as the oxidizer and the flame is highly stable for both 40-mm 5-inlet and 40 mm 3-inlet combustors for a wide range of equivalence ratios. The flames have been found to survive for both extreme lean and rich mixtures for a given mass flow rate for CH4-O2 combustion. Copyright © 2012 American Institute of Aeronautics and Astronautics, Inc. Source


Yamaguchi C.,University of Texas at El Paso | Lee W.-Y.,University of Texas at El Paso | Lee W.-Y.,500 iversity Ave
Journal of Chromatography A | Year: 2010

A simple, cost effective, and yet sensitive sample preparation technique was investigated for determining Polycyclic Aromatic Hydrocarbons (PAHs) in solid samples. The method comprises ultrasonic extraction, Stir Bar Sorptive Extraction (SBSE), and thermal desorption-gas chromatography-mass spectrometry to increase analytical capacity in laboratories. This method required no clean-up, satisfied PAHs recovery, and significantly advances cost performance over conventional extraction methods, such as Soxhlet and Microwave Assisted Extraction (MAE). This study evaluated three operational parameters for ultrasonic extraction: solvent composition, extraction time, and sample load. A standard material, SRM 1649 a (urban dust), was used as the solid sample matrix, and 12 priority PAHs on the US Environmental Protection Agency (US EPA) list were analyzed. Combination of non-polar and polar solvents ameliorated extraction efficiency. Acetone/hexane mixtures of 2:3 and 1:1 (v/v) gave the most satisfactory results: recoveries ranged from 63.3% to 122%. Single composition solvents (methanol, hexane, and dichloromethane) showed fewer recoveries. Comparing 20min with 60min sonication, longer sonication diminished extraction efficiencies in general. Furthermore, sample load became a critical factor in certain solvent systems, particularly MeOH. MAE was also compared to the ultrasonic extraction, and results determined that the 20-min ultrasonic extraction using acetone/hexane (2:3, v/v) was as potent as MAE. The SBSE method using 20mL of 30% alcohol-fortified solution rendered a limit of detection ranging from 1.7 to 32ngL-1 and a limit of quantitation ranging from 5.8 to 110ngL-1 for the 16 US EPA PAHs. © 2010 Elsevier B.V. Source


Cappelle M.,500 iversity Ave | Davis T.A.,500 iversity Ave | Camacho L.M.,500 iversity Ave | Brandhuber P.,HDR | And 3 more authors.
AMTA/AWWA Membrane Technology Conference and Exposition 2013 | Year: 2013

UTEP and Veolia Water Solutions & Technologies have been demonstrating and commercializing the Zero Discharge Desalination (ZDD) technology as part of a three year project sponsored by the U.S. Bureau of Reclamation. ZDD is able to achieve up to 98% recovery by desalinating brackish groundwater. ZDD is typically comprised of a reverse osmosis (RO) or nanofiltration (NF) system and a unique variation of electrodialysis called electrodialysis metathesis (EDM). The ZDD technology increases the yield of fresh water from water supplies that contain enough CaSO4 to cause precipitation problems when the water is treated with RO or NF alone. The EDM is the heart of the ZDD treatment system and it removes CaSO4 and other troublesome salts. NaCl is the major consumable of the ZDD process and is a cost driver for desalination operations. UTEP is performing several laboratory experiments to evaluate the potential to recover NaCl and other useful salts from the ZDD process streams. Results are presented on the recovery of NaCl, Mg(OH)2, and CaSO4 from simulated EDM concentrate streams and EDM concentrate streams from ZDD treatment of brackish groundwater from Alamogordo, New Mexico and La Junta, Colorado. © 2013 American Water Works Association. Source


Yanez M.,500 iversity Ave | Rincon J.,500 iversity Ave | Cortez P.,500 iversity Ave | Gunther N.,500 iversity Ave | And 2 more authors.
Journal of Imaging Science and Technology | Year: 2012

The current engineered skin substitutes for diabetic foot ulcer treatment lack effective host integration. The goal of this research is to create a wound care material that promotes integration with host tissue. We have been investigating a printable biodegradable scaffold composed of gelatin and oxidized alginate, both materials with very high biocompatibility and low toxicity. We investigated the printability of oxidized alginate and its use as an 'ink' for drop-on-demand crosslinking of gelatin. The oxidized alginate was characterized by Fourier transform infrared spectrophotometry. Crosslinking rates were investigated as a function of crosslinker concentration. Crosslinking densities were measured by trinitrobenzene sulfonic acid assay. The mechanical properties of the crosslinked gels were measured in dried samples. The biocompatibility and ability of the printed scaffolds to support fibroblast attachment and proliferation were tested. Our results show that using 15% oxidized alginate and 10% gelatin allows us to obtain skin wound dressings with better properties. © 2012 Society for Imaging Science and Technology. Source

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