This paper draws heavily on the authors’ previously published research to explore the extent to which near term carbon dioxide-driven enhanced oil recovery (CO2-EOR) can be “a stepping stone to a long term sequestration program of a scale to be material in climate change risk mitigation.” The paper examines the historical evolution of CO2-EOR in the United States and concludes that estimates of the cost of CO2-EOR production or the extent of CO2 pipeline networks based upon this energy security-driven promotion of CO2-EOR do not provide a robust platform for spurring the commercial deployment of carbon dioxide capture and storage technologies (CCS) as a means of reducing greenhouse gas emissions. The paper notes that the evolving regulatory framework for CCS makes a clear distinction between CO2-EOR and CCS and the authors examine arguments in the technical literature about the ability for CO2-EOR to generate offsetting revenue to accelerate the commercial deployment of CCS systems in the electric power and industrial sectors of the economy. The authors conclude that the past 35 years of CO2-EOR in the U.S. have been important for boosting domestic oil production and delivering proven system components for future CCS systems. However, though there is no reason …

Python extensions are usually created by writing the glue that connects Python to the desired new functionality in the C language. While simple extensions do not require much effort, to do the job correctly with full error checking is tedious and prone to errors in reference counting and to memory leaks, especially when errors occur. The resulting program is difficult to read and maintain. By designing suitable C++ classes to wrap the Python C API, we are able to produce extensions that are correct and which clean up after themselves correctly when errors occur. This facility also integrates the C++ and Python exception facilities. This paper briefly describes our package for this purpose, named CXX. The emphasis is on our design choices and the way these contribute to the construction of accurate Python extensions. We also briefly relate the way CXX's facilities for sequence classes allow use of C++'s Standard Template Library (STL) algorithms on C++ sequences.

Cells use feedback to implement a diverse range of regulatory functions. Building synthetic feedback control systems may yield insight into the roles that feedback can play in regulation since it can be introduced independently of native regulation, and alternative control architectures can be compared. We propose a model for microbial biofuel production where a synthetic control system is used to increase cell viability and biofuel yields. Although microbes can be engineered to produce biofuels, the fuels are often toxic to cell growth, creating a negative feedback loop that limits biofuel production. These toxic effects may be mitigated by expressing efflux pumps that export biofuel from the cell. We developed a model for cell growth and biofuel production and used it to compare several genetic control strategies for their ability to improve biofuel yields. We show that controlling efflux pump expression directly with a biofuel-responsive promoter is a straight forward way of improving biofuel production. In addition, a feed forward loop controller is shown to be versatile at dealing with uncertainty in biofuel production rates.

The solvent extraction of thorium with 42.5% TBP in a Decalin diluent was studied in a compound pulse column. The HETS for the extraction section of the column was 4.7 feet. A discussion of the method of gaphical calculations of a compound column is included. (auth)

The Washington State Department of Ecology (Ecology) approved the construction and operation of Rotary Mode Core Sampling (RMCS) System Two on November 22, 1993 (NOC-93-04). This approval supported the characterization of waste in the single-shell tanks (SSTS) and double-shell tanks (DSTS) on the Hanford Site. The waste tank characterization sampling and analysis effort is vital to the safe operations of the Hanford Site tank farms, and the timely collection of the information necessary to support retrieval, pretreatment, disposal planning, and final closure strategy. This is based on the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 93-05 Implementation Plan (DOE-RL-94-001), US Department of Energy, Richland Operations Office (DOE-RL) proposed the expedited construction and operation of two additional RMCS systems to support characterization of waste stored in SSTs and DSTS. RMCS currently is scheduled for approximately 50 (active or passively ventilated) of the 149 SSTs in the 200 East and 200 West Areas. If necessary, the RMCS will be used to sample other tanks currently not scheduled, subject to the requirements of this document and any applicable Ecology approval order. The typical components of the RMCS systems are shown in Figure 1. It should be noted that the Flammable Gas Detector cart …

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This safety analysis report for packaging (SARP) documents the safety of shipments of irradiated fuel elements in the MUlticanister Overpack (MCO) and MCO Cask for a highway route controlled quantity, Type B fissile package. This SARP evaluates the package during transfers of (1) water-filled MCOs from the K Basins to the Cold Vacuum Drying Facility (CVDF) and (2) sealed and cold vacuum dried MCOs from the CVDF in the 100 K Area to the Canister Storage Building in the 200 East Area.

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Atmospheric transport and diffusion models have been developed by the Environmental Technology Section (ETS) of the Savannah River Technology Center to calculate the location and concentration of toxic or radioactive materials during an accidental release at the Savannah River Site (SRS). The output from these models has been used to support initial on-site and off-site emergency response activities such as protective action decision making and field monitoring coordination. These atmospheric transport and diffusion models have been incorporated into an automated computer-based system called the (Weather Information and Display) System and linked to real-time meteorological and radiological monitoring instruments to provide timely information for these emergency response activities (Hunter, 1990). This study will compare two of the WIND System annospheric models, PUFF/PLUME and 2DPUF, with a select group of MATS experiments and examine the results in detail to determine the performance of the models. Additional results from this study can be found in Fast et al. (1991).

Atmospheric transport and diffusion models have been developed by the Environmental Technology Section (ETS) of the Savannah River Technology Center to calculate the location and concentration of toxic or radioactive materials during an accidental release at the Savannah River Site (SRS). The output from these models has been used to support initial on-site and off-site emergency response activities such as protective action decision making and field monitoring coordination. These atmospheric transport and diffusion models have been incorporated into an automated computer-based system called the (Weather Information and Display) System and linked to real-time meteorological and radiological monitoring instruments to provide timely information for these emergency response activities (Hunter, 1990). This study will compare two of the WIND System annospheric models, PUFF/PLUME and 2DPUF, with a select group of MATS experiments and examine the results in detail to determine the performance of the models. Additional results from this study can be found in Fast et al. (1991).

The complete genomic sequence of Pseudomonas syringae pathovar syringae B728a (Pss B728a), has been determined and is compared with that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 megabases) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. While a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared to Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences (REPs) unique to Pss B728a when compared to Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands vary, with one containing a prophage and another the plasmid pKLC102 of P. aeruginosa …

Methods for dissolving unirradiated uranium-molybdenum alloy reactcr fuels in nitric acid, nitric acid--ferric nitrate, and nitric acid-- phosphoric acid solutions were studied on a laboratory scale. Flowsheets based on the results propose dissolution of alloys containing 3% molybdenum in boiling 6 M HNO/ sub 3/ to yield stsble solutions that are 0.6 M in uranium and 3 to 4 M in nitric acid. The uranium can then be easily decontaminated and recovered in a conventional Purex-type tributyl phosphate solvent extraction process. Alloys containing 10% molybdenum would be dissolved in boiling 11 M HNO/sub 3/, allowing molybdic oxide to precipitate. The molybdic oxide, which carries 5-10% of the uranium, is removed by centrifugation and the acidity of the supernatant solution adjusted tc allow recovery of the uranium by Purex-type solvent extraction procedures. The uranium carried by the molybdic oxide is recovered after the MoO/ sub 3/ is dissolved in warm 5 M NaOH. Less than 0.1% of the uranium is solubilized during the caustic dissolution. Alternative methods investigated involve dissolution in nitric acid containing 0.5 to 1 M ferric nitrate to complex the molybdenum. These techniques lead to undesirably large volumes of high-level solvent extraction waste solutions. Phosphate ion is also …

Accurate seismic event location is key to monitoring the Comprehensive Nuclear-Test-Ban Treaty (CTBT) and is largely dependent on our understanding of the crust and mantle velocity structure. This is particularly challenging in aseismic regions, devoid of calibration data, which leads us to rely on a priori constraints on the velocities. We investigate our ability to improve seismic event location in the Middle East, North Africa, and the Former Soviet Union (ME/NA/FSU) by using a priori three-dimensional (3-D) velocity models in lieu of more commonly used one dimensional (1-D) models. Event locations based on 1-D models are often biased, as they do not account for significant travel-time variations that result from heterogeneous crust and mantle; it follows that 3-D velocity models have the potential to reduce this bias. Here, we develop a composite 3-D model for the ME/NA/FSU regions. This fully 3-D model is an amalgamation of studies ranging from seismic reflection to geophysical analogy. Our a priori model specifies geographic boundaries and velocity structures based on geology, tectonics, and seismicity and information taken from published literature, namely a global sediment thickness map of 1{sup o} resolution (Laske and Masters, 1997), a regionalized crustal model based on geology and tectonics (Sweeney …

OTS). The situation of a leak of sctiwe material into a flowing air- stream presents the problem of determining possible upstream diffusion of the activity. In a constant velocity one directional flow involving three dimensional diffusion from a point source, the upstream concentration is severely limited compared to that downstream. For all practical values of the flow velocity and diffusion coefficients, this upstream concentration is negligible. It is to be noted, however, that the velocity profile of a flow in a finite channel involves points of very low velocity, and at these points the diffusion effect might predominate, resulting in some upstream diffusion. Even in this case, unknown convection effects would be more important than diffusion effects. (auth)

The purpose of this project was to perform a finite element analysis of a pressurized water reactor pressurizer surge nozzle mock-up to predict both the weld residual stresses created in its construction and the final stress state after the application of the Mechanical Stress Improvement Process (MSIP). Strain gages were applied to the inner diameter of the mock-up to record strain changes during the MSIP. These strain readings were used in an attempt to calculate the final stress state of the mock-up as well.

A quantitative study of mixing, which utilized the exit age distribution theory, has been completed for bench-scale annular and raschig ring filled tanks, in addition to a pilot-scale annular tank. A study of mixing and fluid flow in a full-scale, single-entry, raschig ring filled tank also was initiated. Results showed the bench-scale raschig ring filled tank approached plug-flow (no mixing) behavior. In a bench-scale annular tank, regardless of whether fluid entered tangentially or nontangentially, the vessel approached continuously stirred tank reactor behavior (perfect mixing). The pilot-scale annular tank approached continuously stirred tank reactor behavior only when tangential entry was used. Mixing in the full-scale raschig ring filled tank he tank did not approach eithr the perfect or the no mixing situations. Instead, the tank had a flow pattern in which solution channeled through a small volume of the tank, leaving the regions outside the channel effectively inactive.

Rocky Flats Environmental Technology Site (RFETS), has approximately 10,000 High Efficiency Particulate Air (HEPA) Filters installed in a variety of filter plenums. These ventilation/filtration plenum systems are used to control the release of airborne particulate contaminates to the environment during normal operations and potential accidents. This report summarizes the results of destructive and non-destructive tests on HEPA filters obtained from a wide variety of ages and service conditions. These tests were performed to determine an acceptable service life criteria for HEPA filters used at Rocky Flats Environmental Technology Site (RFETS). A total of 140 filters of various ages (1972 to 1996) and service history (new, aged unused, used) were tested. For the purpose of this report, filter age from manufacture date/initial test date to the current sample date was used, as opposed to the actual time a filter was installed in an operating system.

Heated wells in gloveboxes have been used for many years by the Argonne National Laboratory Chemical Technology Division for nuclear-technology, waste-management, chemical-technology, and analytical-chemistry research. These wells allow experiments to be isolated from the main working volume of the glovebox. In addition, wells, when sealed, allow experiments to be conducted under pressurized or vacuum conditions. Until recently, typical maximum operational temperatures were about 500 C. However, more recent research is requiring operational temperatures approaching 900 C. These new requirements pose interesting design challenges that must be resolved. Some problem areas include temperature effects on material properties, maintaining a seal, cooling selected areas, and minimizing stresses. This paper discusses issues related to these design challenges and the ways in which these issues have been resolved.

Conductor inks containing silver and palladium, used in ceramic co-fired circuits, sometimes undergo an anomalously large expansion during heating in the temperature range where interdiffusion occurs. Therefore, the interdiffusion of silver and palladium was studied during heating in both air and argon using both powder and foil samples. Measurements on a powder compact made of a mixture of Ag and Pd (80% Ag) particles indicated that a very rapid expansion occurred between 375 and 400 C when heated in air but only a slight expansion occurred in Ar. A pre-alloyed powder with the same composition did not expand during heating. In situ high temperature x-ray diffraction studies indicated that both powders oxidized during heating in air, with the mixture oxidizing more and that interdiffusion occurred between 300 and 500 C. Microstructural examination indicated that larger particles with internal pores had formed in the mixture heated in air to 375 C due to rearrangement during interdiffusion. A porous region much thicker than the original silver film formed on a palladium foil sample when it was heated in air, whereas in inert atmosphere pores formed only in the silver film, indicating a Kirkendall effect occurs in both cases. Based on these results, …

Two detailed, unit-cell models, a transverse fin design and a longitudinal fin design, of a combined hydride bed and heat exchanger are developed in COMSOL{reg_sign} Multiphysics incorporating and accounting for heat transfer and reaction kinetic limitations. MatLab{reg_sign} scripts for autonomous model generation are developed and incorporated into (1) a grid-based and (2) a systematic optimization routine based on the Nelder-Mead downhill simplex method to determine the geometrical parameters that lead to the optimal structure for each fin design that maximizes the hydrogen stored within the hydride. The optimal designs for both the transverse and longitudinal fin designs point toward closely-spaced, small cooling fluid tubes. Under the hydrogen feed conditions studied (50 bar), a 25 times improvement or better in the hydrogen storage kinetics will be required to simultaneously meet the Department of Energy technical targets for gravimetric capacity and fill time. These models and methodology can be rapidly applied to other hydrogen storage materials, such as other metal hydrides or to cryoadsorbents, in future work.

The environments on the drip shield and waste package outer barrier are controlled by the compositions of the waters that contact these components. the temperature (T) of these components, and the effective relative humidity (RH) at these components. Because the composition of the waters that are expected to enter the emplacement drifts (either by seepage flow or by episodic flow) have not been specified: well J13 water was chosen as the reference water (Harrar 1990). Section 6.2 discusses the accessible RH for the temperatures of interest at the repository horizon. Section 6.3 discusses the adsorption of water on metal alloys in the absence of hygroscopic salts. Because the temperatures of the DSs and the WPOBs are higher than those of the surrounding near-field environment, the relative humidity at the DSs and the WPOBs will be lower than that of the surrounding near-field environment. This difference is a result of the water partial pressure in the drift being constant and no higher than the equilibrium water vapor pressure at the temperature of the drift wall.

Analytical estimate of the number of muons that must decay in the straight section of a storage ring to produce a neutrino & anti-neutrino beam of sufficient intensity to facilitate cross-section measurements with a statistical precision of 1%. As we move into the era of precision long-baseline {nu}{sub {mu}} {yields} {nu}{sub e} and {bar {nu}}{sub {mu}} {yields} {bar {nu}}{sub e} measurements there is a growing need to precisely determine the {nu}{sub e} and {bar {nu}}{sub e} cross-sections in the relevant energy range, from a fraction of 1 GeV to a few GeV. This will require {nu}{sub e} and {bar {nu}}{sub e} beams with precisely known fluxes and spectra. One way to produce these beams is to use a storage ring with long straight sections in which muon decays ({mu}{sup -} {yields} e{sup -}{nu}{sub {mu}}{bar {nu}}{sub e} if negative muons are stored, and {nu}{sup +} {yields} e{sup +}{nu}{sub e}{bar {nu}}{sub {mu}} if positive muons are stored) produce the desired beam. The challenge is to capture enough muons in the ring to obtain useful neutrino and anti-neutrino fluxes. Early proposals to use a muon storage ring for neutrino oscillation experiments were based upon injecting 'high energy' charged pions into the ring which …

The main objective of this research was to develop new computational tools for the simulation and analysis of plasticity and fracture mechanisms of fusion materials, and to assist in planning and assessment of corresponding radiation experiments.

Gas-solid flows occur frequently in many industrial processes and systems, such as in pulverized coal transport pipelines and portions of fluid catalytic cracking (FCC) risers. Many of these systems have been modeled and optimized over the years by ''engineering know-how,'' which has been derived from the operating experience with the unit. However, it is being recognized that a more detailed, analytic tool is necessary to improve the efficiency of these systems due to heightened industrial competitiveness. In addition to this competition, increasingly stringent environmental regulations force the industry to improve their systems to comply with these regulations. In part, these two conditions explain the recent interest in computational fluid dynamics (CFD) applied to industrial systems. A successfully validated CFD simulation can provide detailed information on an industrial flow system based on a limited amount of experimental data. Once a CFD code has been properly validated, it may then be used to suggest optimal operating conditions. Given the wide range of information provided by a CFD code, the term ''optimal'' may refer to optimal material output, optimal energy efficiency, minimal (optimal) pollutant emission, or optimal lowest operating cost, for example. This versatility has been recently recognized by a number of industries …