scholarly journals Integrated characterization of subsurface media from locations up- and down-gradient of a uranium-contaminated aquifer

2019 ◽  
Author(s):  
Ji-Won Moon ◽  
Charles J. Paradis ◽  
Dominique C. Joyner ◽  
Frederick von Netzer ◽  
Erica L. Majumder ◽  
...  
Keyword(s):  
Trace Elements ◽  
Clay Minerals ◽  
Pore Water ◽  
The United States ◽  
Department Of Energy ◽  
United States Department ◽  
Sediment Structure ◽  
Core Sediments ◽  
Oak Ridge ◽  
Geochemical Properties

AbstractThe processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated environments. To provide site assessment for a larger study, we processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater from the ENIGMA Field Research Site at the United States Department of Energy (DOE) Oak Ridge Reservation (ORR). We compared fresh core sediments by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including contaminants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. This environmental systems approach provided detailed site-specific biogeochemical information from the various properties of subsurface media to reveal the influences of solid, liquid, and gas phases. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate- reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. This suggested that groundwater predominantly flowed through preferential paths with high flux and little mixing with water in the interstices of sediment particles, which could impact microbial activity. The abundant clay minerals with high surface area and high water-holding capacity of micro-pores of the fine clay rich layer suggest suppression of nutrient supply to microbes from the surface. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of highly toxic elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments.

An Overview of the Direct Energy Conversion Proof of Principle Power Production Program

2004 ◽  
Author(s):  
D. King ◽  
G. Rochau ◽  
D. Oscar ◽  
C. Morrow ◽  
P. Tsvetkov ◽  
...  
Keyword(s):  
Energy Conversion ◽  
The United States ◽  
Department Of Energy ◽  
Future Research ◽  
United States Department ◽  
Commercial Development ◽  
Direct Energy Conversion ◽  
Project Description ◽  
Direct Energy ◽  
Proof Of Principle

The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy conversion as any fission process that returns usable energy without an intermediate thermal process. A prior Direct Energy Conversion (DEC) project [1] has been completed and indicates that a viable direct energy device is possible if several technological issues can be overcome. The DECPOP program is focusing on two of the issues: charged particle steering and high voltage hold-off. This paper reports on the progress of the DECPOP project. Two prototype concepts are under development: a Fission Electric Cell using magnetic insulation and a Fission Fragment Magnetic Collimator using magnetic fields to direct fission fragments to collectors. Included in this paper are a short project description, an abbreviated summary of the work completed to date, a description of ongoing and future project activities, and a discussion of the potential for future research and development.

Investigation of the Down-Scaling Effects on the Low Swirl Burner and its Application to Microturbines

2018 ◽  
Author(s):  
Alex Frank ◽  
Peter Therkelsen ◽  
Miguel Sierra Aznar ◽  
Vi H. Rapp ◽  
Robert K. Cheng ◽  
...  
Keyword(s):  
Power Systems ◽  
Power Plants ◽  
Energy Savings ◽  
The United States ◽  
Primary Energy ◽  
Department Of Energy ◽  
Small Scale ◽  
United States Department ◽  
Scaling Effects ◽  
Swirl Burner

About 75% of the electric power generated by centralized power plants feeds the energy needs from the residential and commercial sectors. These power plants waste about 67% of primary energy as heat emitting 2 billion tons of CO2 per year in the process (∼ 38% of total US CO2 generated per year) [1]. A study conducted by the United States Department of Energy indicated that developing small-scale combined heat and power systems to serve the commercial and residential sectors could have a significant impact on both energy savings and CO2 emissions. However, systems of this scale historically suffer from low efficiencies for a variety of reasons. From a combustion perspective, at these small scales, few systems can achieve the balance between low emissions and high efficiencies due in part to the increasing sensitivity of the system to hydrodynamic and heat transfer effects. Addressing the hydrodynamic impact, the effects of downscaling on the flowfield evolution were studied on the low swirl burner (LSB) to understand if it could be adapted to systems at smaller scales. Utilizing particle image velocimetry (PIV), three different swirlers were studied ranging from 12 mm to 25.4 mm representing an output range of less than 1 kW to over 23 kW. Results have shown that the small-scale burners tested exhibited similar flowfield characteristics to their larger-scale counterparts in the non-reacting cases studied. Utilizing this data, as a proof of concept, a 14 mm diameter LSB with an output of 3.33 kW was developed for use in microturbine operating on a recuperated Brayton cycle. Emissions results from this burner proved the feasibility of the system at sufficiently lean mixtures. Furthermore, integration of the newly developed LSB into a can style combustor for a microturbine application was successfully completed and comfortably meet the stringent emissions targets. While the analysis of the non-reacting cases was successful, the reacting cases were less conclusive and further investigation is required to gain an understanding of the flowfield evolution which is the subject of future work.

H2S and HS- Adsorption on a Charged Cu Surface in an Electrolyte: Effect of Ionic Strength

1997 ◽  
Vol 492 ◽  
Author(s):  
W. D. Wilson ◽  
C. M. Schaldach
Keyword(s):  
Ionic Strength ◽  
The United States ◽  
Binding Energies ◽  
Department Of Energy ◽  
Molecular Surface ◽  
Double Layers ◽  
Real Surface ◽  
United States Department ◽  
Surface Charges ◽  
Hartree Fock

ABSTRACTWe present a method for the calculation of the binding and rotational energies of neutral (H2S) and charged (HS-) molecules impinging upon a charged (Cu <100>) surface in the presence of an electrolyte. A molecular surface is constructed surrounding the H2S and HS- molecules forming boundary elements. A coupled Schrödinger-Poisson-Boltzmann iterative procedure treats the electronic structure of the molecules at the 6–31G**/MP2 level of theory and includes solvation effects through the single and double layers of charge induced by the electronic distribution. The molecule, together with its charged layers, forms a Molecular Single and Double Layer (MSDL), an object which then interacts with a Gouy-Chapman plane within the electrolyte. The additional induced charge at the molecular surface resulting from this electric field is obtained by solving a second set of boundary element equations. Repulsive interactions between the atoms of the molecule and those of the surface are obtained using a rigid-ion Hartree-Fock method. Binding energies of the molecule to the surface are determined as a function of the real surface charge imposed and also the ionic strength of the solution. It is found that surface charges can completely (180°) reorient these molecules and that the counterions in the solution can completely screen binding effects of even large surface charges.Work supported by the United States Department of Energy under contract #DE-AC04–94AL85000.

Application of SPSLIFE to Preliminary Design Evaluation and Life Assessment of CSGT Components

1995 ◽  
Vol 117 (3) ◽  
pp. 424-431
Author(s):  
A. Saith ◽  
P. F. Norton ◽  
V. M. Parthasarathy
Keyword(s):  
Gas Turbines ◽  
Computer Code ◽  
The United States ◽  
Department Of Energy ◽  
Life Assessment ◽  
Design Evaluation ◽  
United States Department ◽  
Preliminary Design ◽  
Detail Design ◽  
Stage 1

The Ceramic Stationary Gas Turbine (CSGT) Program has utilized the SPSLIFE computer code to evaluate the preliminary design of ceramic components. The CSGT program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. Preliminary design evaluation and life assessment results are presented here for the following components: (1) Stage 1 turbine blade, (2) Stage 1 turbine nozzle, and (3) combustor inner liner. From the results of the analysis, recommendations are made for improving the life and reliability of the components. All designs were developed in Phase I (preliminary design) of the CSGT program and will be optimized in Phase II (detail design) of the program.

The AGT101 Advanced Automotive Gas Turbine

1982 ◽  
Author(s):  
R. A. Rackley ◽  
J. R. Kidwell
Keyword(s):  
United States ◽  
Gas Turbine ◽  
The United States ◽  
Gas Turbine Engine ◽  
Development Project ◽  
Single Stage ◽  
Department Of Energy ◽  
Inlet Temperature ◽  
United States Department ◽  
Turbine Engine

The Garrett/Ford Advanced Gas Turbine Powertrain System Development Project, authorized under NASA Contract DEN3-167, is sponsored by and is part of the United States Department of Energy Gas Turbine Highway Vehicle System Program. Program effort is oriented at providing the United States automotive industry the technology base necessary to produce gas turbine powertrains competitive for automotive applications having: (1) reduced fuel consumption, (2) multi-fuel capability, and (3) low emissions. The AGT101 powertrain is a 74.6 kW (100 hp), regenerated single-shaft gas turbine engine operating at a maximum turbine inlet temperature of 1644 K (2500 °F), coupled to a split differential gearbox and Ford automatic overdrive production transmission. The gas turbine engine has a single-stage centrifugal compressor and a single-stage radial inflow turbine mounted on a common shaft. Maximum rotor speed is 10,472 rad/sec (100,000 rpm). All high-temperature components, including the turbine rotor, are ceramic. AGT101 powertrain development has been initiated, with testing completed on many aerothermodynamic components in dedicated test rigs and start of Mod I, Build 1 engine testing.

Application of Spslife to Preliminary Design Evaluation and Life Assessment of CSGT Components

1994 ◽  
Author(s):  
Arun Saith ◽  
Paul F. Norton ◽  
Vijay M. Parthasarathy
Keyword(s):  
Gas Turbines ◽  
Computer Code ◽  
The United States ◽  
Department Of Energy ◽  
Life Assessment ◽  
Design Evaluation ◽  
United States Department ◽  
Preliminary Design ◽  
Detail Design ◽  
Stage 1

The Ceramic Stationary Gas Turbine (CSGT) Program has utilized the SPSLIFE computer code to evaluate the preliminary design of ceramic components. The CSGT program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. Preliminary design evaluation and life assessment results are presented here for the following components: (1) Stage 1 Turbine Blade, (2) Stage 1 Turbine Nozzle, and (3) Combustor Inner Liner. From the results of the analysis, recommendations are made for improving the life and reliability of the components. All designs were developed in Phase I (preliminary design) of the CSGT program and will be optimized in Phase II (detail design) of the program.

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