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A head-end processing step, termed DEOX for its emphasis on decladding via oxidation, is being developed for the treatment of spent oxide fuel by pyroprocessing techniques. The head-end step employs high temperatures to oxidize UO2 to U3O8 resulting in the separation of fuel from cladding and the removal of volatile fission products. Development of the head-end step is being performed in collaboration with the Korean Atomic Energy Research Institute (KAERI) through an International Nuclear Energy Research Initiative. Following the initial experimentation for the removal of volatile fission products, an off-gas treatment system was designed in conjunction with KAERI to collect specific fission gases. The primary volatile species targeted for trapping were iodine, technetium, and cesium. Each species is intended to be collected in distinct zones of the off-gas system and within those zones, on individual filters. Separation of the volatile off-gases is achieved thermally as well as chemically given the composition of the filter media. A description of the filter media and a basis for its selection will be given along with the collection mechanisms and design considerations. In addition, results from testing with the off-gas treatment system will be presented.

AbstractA molecular dyad and triad, comprised of a known photosensitizer, BF2‐chelated dipyrromethane (BDP), covalently linked to its structural analog and near‐IR emitting sensitizer, BF2‐chelated tetraarylazadipyrromethane (ADP), have been newly synthesized and the photoinduced energy and electron transfer were examined by femtosecond and nanosecond laser flash photolysis. The structural integrity of the newly synthesized compounds has been established by spectroscopic, electrochemical, and computational methods. The DFT calculations revealed a molecular‐clip‐type structure for the triad, in which the BDP and ADP entities are separated by about 14 Å with a dihedral angle between the fluorophores of around 70°. Differential pulse voltammetry studies have revealed the redox states, allowing estimation of the energies of the charge‐separated states. Such calculations revealed a charge separation from the singlet excited BDP (1BDP*) to ADP (BDP.+‐ADP.−) to be energetically favorable in nonpolar toluene and in polar benzonitrile. In addition, the excitation transfer from the singlet BDP to ADP is also envisioned due to good spectral overlap of the BDP emission and ADP absorption spectra. Femtosecond laser flash photolysis studies provided concrete evidence for the occurrence of energy transfer from 1BDP* to ADP (in benzonitrile and toluene) and electron transfer from BDP to 1ADP* (in benzonitrile, but not in toluene). The kinetic study of energy transfer was measured by monitoring the rise of the ADP emission and revealed fast energy transfer (ca. 1011 s−1) in these molecular systems. The kinetics of electron transfer via 1ADP*, measured by monitoring the decay of the singlet ADP at λ=820 nm, revealed a relatively fast charge‐separation process from BDP to 1ADP*. These findings suggest the potential of the examined ADP–BDP molecules to be efficient photosynthetic antenna and reaction center models.

In this study, we attempted to evaluate relative significance of the factors that have been proposed to affect the electrochemical reaction of coals in a direct carbon fuel cell (DCFC). In the pres...

Modeling of Coupled Thermodynamic and Geomechanical Performance of Underground Compressed Air Energy Storage (CAES) in Lined Rock Caverns Jonny Rutqvist 1 , Hyung-Mok Kim 2 , Dong-Woo Ryu 2 , Joong-Ho Synn 2 , Won-Kyong Song 2 Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720 U.S.A. Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 305-350 Korea ACKNOWLEDGMENTS This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM, GP2009-019) funded by the Ministry of Knowledge and Economy of Korea, and funding from KIGAM for Dr. Jonny Rutqvist and Berkeley Lab was provided through the U.S. Department of Energy Contract No. DE-AC02-05CH11231. Technical review by Dr. Curtis Oldenburg and editorial review by Dan Hawkes, both at Berkeley Lab are greatly appreciated.

The ability to generate microorganisms that can produce biofuels similar to petroleum-based transportation fuels would allow the use of existing engines and infrastructure and would save an enormous amount of capital required for replacing the current infrastructure to accommodate biofuels that have properties significantly different from petroleum-based fuels. Several groups have demonstrated the feasibility of manipulating microbes to produce molecules similar to petroleum-derived products, albeit at relatively low productivity (e.g. maximum butanol production is around 20 g/L). For cost-effective production of biofuels, the fuel-producing hosts and pathways must be engineered and optimized. Advances in metabolic engineering and synthetic biology will provide new tools for metabolic engineers to better understand how to rewire the cell in order to create the desired phenotypes for the production of economically viable biofuels.

A 'molecular clip' featuring a near-IR emitting fluorophore, BF(2)-chelated tetraarylazadipyrromethane (aza-BODIPY) covalently linked to two porphyrins (MP, M = 2H or Zn) has been newly synthesized to host a three-dimensional electron acceptor fullerene via a 'two-point' metal-ligand axial coordination. Efficient singlet-singlet excitation transfer from (1)ZnP* to aza-BODIPY was witnessed in the dyad and triad in nonpolar and less polar solvents, such as toluene and o-dichlorobenzene, however, in polar solvents, additional electron transfer occurred along with energy transfer. A supramolecular tetrad was formed by assembling bis-pyridine functionalized fullerene via a 'two-point' metal-ligand axial coordination, and the resulted complex was characterized by optical absorption and emission, computational, and electrochemical methods. Electron transfer from photoexcited zinc porphyrin to C(60) is witnessed in the supramolecular tetrad from the femtosecond transient absorption spectral studies. Further, the supramolecular polyads (triad or tetrad) were utilized to build photoelectrochemical cells to check their ability to convert light into electricity by fabricating FTO/SnO(2)/polyad electrodes. The presence of azaBODIPY and fullerene entities of the tetrad improved the overall light energy conversion efficiency. An incident photon-to-current conversion efficiency of up to 17% has been achieved for the tetrad modified electrode.

We present a novel binder-free multiwall carbon nanotube (MWCNT) structure as an anode in Li ion batteries. The interface-controlled MWCNT structure, synthesized through a two-step process of catalyst deposition and chemical vapor deposition (CVD) and directly grown on a copper current collector, showed very high specific capacity, almost three times as that of graphite, excellent rate capability even at a charging/discharging rate of 3 C, and no capacity degradation up to 50 cycles. Significantly enhanced properties of this anode could be related to high Li ion intercalation on the carbon nanotube walls, strong bonding with the substrate, and excellent conductivity.

Abstract Hydrolysis of lignocellulosic biomass is important for isolation of glucose in a biorefinery. In this research, intermittent ball milling was applied to facilitate and enhance enzymatic hydrolysis of dilute acid-pretreated lignocellulosic biomass, with the highest glucose yield of 66.5% at a low enzyme dose (10 FPU g−1 glucan) over 24h. In comparison, the yield for the typical liquid-state enzymatic hydrolysis was only 38.7% for 24h, although it reached 69.0% after 72h. Glucose yield increased further to 84.7% using the delignified lignocellulosic biomass after a 24 h intermittent ball milling process. The observed glucose yield (24h) is comparable to the desired 80% (72h) milestone yield set by the US DOE but only with a three times shorter processing time despite the differences in experimental conditions. Further, the amount of solvent needed for the intermittent ball milling process was 25-folds reduced, compared with typical hydrolysis. Intermittent ball milling was useful for enhancing the performance of enzymatic hydrolysis with favorable adsorption of enzymes into cellulose. It also exhibited high efficiency in enzymatic hydrolysis of lignocellulosic biomass relative to continuous ball milling. It was suggested that ball milling could help distribute enzymes into cellulose, however, continuous ball milling would simultaneously separate enzymes from cellulose before the completion of hydrolysis. Therefore, intermittent ball milling could facilitate enzymes distribution and leave enough time for them to consume the boned cellulose chains. This technology should be beneficial for development of more effective and environmentally benign approaches to enzymatic hydrolysis to effectively isolate glucose from lignocellulosic biomass.