The Influence of deep-sea bed CO2 sequestration on small metazoan (meiofaunal) community structure and function (open access)

The Influence of deep-sea bed CO2 sequestration on small metazoan (meiofaunal) community structure and function

We conducted a series of experiments in Monterey Submarine Canyon to examine potential ecological impacts of deep-ocean CO2 sequestration. Our focus was on responses of meiofaunal invertebrates (< 1 mm body length) living within the sediment at depths ranging between 3000-3600 m. Our particular emphasis was on harpacticoid copepods and nematodes. In the first phase of our DOE funding, we reported findings that suggest substantial (~80%) mortality to harpacticoid copepods. In the second phase of our funding we published additional findings from phase one and conducted follow-up experiments in the Monterey Canyon and in the laboratory. In one experiment we looked for evidence that meiofauna seek to escape areas where CO2 concentrations are elevated. “Emergence traps” near the source of the CO2-rich seawater caught significantly more harpacticoids than those far from it. The harpacticoids apparently attempted to escape from the advancing front of carbon dioxide-rich seawater and therefore presumably found exposure to it to be stressful. Although most were adversely affected, species differed significantly in the degree of their susceptibility. Unexpectedly, six species showed no effect and may be resistant. The hypothesis that harpacticoids could escape the effects of carbon dioxide-rich seawater by moving deeper into the seabed was not …
Date: February 17, 2013
Creator: Carman, Kevin R.; Fleeger, John W. & Thistle, David
System: The UNT Digital Library
Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Biases Using Data Assimilation (open access)

Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Biases Using Data Assimilation

The overall goal of work performed under this grant is to enhance understanding of simulations of present-day climate and greenhouse gas-induced climate change. The examination of present-day climate also includes diagnostic intercomparison of model simulations and observed mean climate and climate variability using reanalysis and satellite datasets. Enhanced understanding is desirable 1) as a prerequisite for improving simulations; 2) for assessing the credibility of model simulations and their usefulness as tools for decision support; and 3) as a means to identify robust behaviors which commonly occur over a wide range of models, and may yield insights regarding the dominant physical mechanisms which determine mean climate and produce climate change. A further objective is to investigate the use of data assimilation as a means for examining and correcting model biases. Our primary focus is on the Arctic, but the scope of the work was expanded to include the global climate system.
Date: February 17, 2010
Creator: DeWeaver, Eric T.
System: The UNT Digital Library
On the selection of dimension reduction techniques for scientific applications (open access)

On the selection of dimension reduction techniques for scientific applications

Many dimension reduction methods have been proposed to discover the intrinsic, lower dimensional structure of a high-dimensional dataset. However, determining critical features in datasets that consist of a large number of features is still a challenge. In this paper, through a series of carefully designed experiments on real-world datasets, we investigate the performance of different dimension reduction techniques, ranging from feature subset selection to methods that transform the features into a lower dimensional space. We also discuss methods that calculate the intrinsic dimensionality of a dataset in order to understand the reduced dimension. Using several evaluation strategies, we show how these different methods can provide useful insights into the data. These comparisons enable us to provide guidance to a user on the selection of a technique for their dataset.
Date: February 17, 2012
Creator: Fan, Y J & Kamath, C
System: The UNT Digital Library
Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems (open access)

Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems

Catalysts provide foundational technology for the development of new materials and can enhance the efficiency of routes to known materials. New catalyst technologies offer the possibility of reducing energy and raw material consumption as well as enabling chemical processes with a lower environmental impact. The rising demand and expense of fossil resources has strained national and global economies and has increased the importance of accessing more efficient catalytic processes for the conversion of hydrocarbons to useful products. The goals of the research are to develop and understand single-site homogeneous catalysts for the conversion of readily available hydrocarbons into useful materials. A detailed understanding of these catalytic reactions could lead to the development of catalysts with improved activity, longevity and selectivity. Such transformations could reduce the environmental impact of hydrocarbon functionalization, conserve energy and valuable fossil resources and provide new technologies for the production of liquid fuels. This project is a collaborative effort that incorporates both experimental and computational studies to understand the details of transition metal catalyzed C-H activation and C-C bond forming reactions with olefins. Accomplishments of the current funding period include: (1) We have completed and published studies of C-H activation and catalytic olefin hydroarylation by TpRu{l_brace}P(pyr){sub 3}{r_brace}(NCMe)R …
Date: February 17, 2011
Creator: Gunnoe, T. Brent
System: The UNT Digital Library
A Maximally Supersymmetric Kondo Model (open access)

A Maximally Supersymmetric Kondo Model

We study the maximally supersymmetric Kondo model obtained by adding a fermionic impurity to N = 4 supersymmetric Yang-Mills theory. While the original Kondo problem describes a defect interacting with a free Fermi liquid of itinerant electrons, here the ambient theory is an interacting CFT, and this introduces qualitatively new features into the system. The model arises in string theory by considering the intersection of a stack of M D5-branes with a stack of N D3-branes, at a point in the D3 worldvolume. We analyze the theory holographically, and propose a dictionary between the Kondo problem and antisymmetric Wilson loops in N = 4 SYM. We perform an explicit calculation of the D5 fluctuations in the D3 geometry and determine the spectrum of defect operators. This establishes the stability of the Kondo fixed point together with its basic thermodynamic properties. Known supergravity solutions for Wilson loops allow us to go beyond the probe approximation: the D5s disappear and are replaced by three-form flux piercing a new topologically non-trivial S3 in the corrected geometry. This describes the Kondo model in terms of a geometric transition. A dual matrix model reflects the basic properties of the corrected gravity solution in its eigenvalue …
Date: February 17, 2012
Creator: Harrison, Sarah; Kachru, Shamit; Torroba, Gonzalo & /Stanford U., Phys. Dept. /SLAC
System: The UNT Digital Library
ANALYSES AND COMPARISON OF BULK AND COIL SURFACE SAMPLES FROM THE DWPF SLURRY MIX EVAPORATOR (open access)

ANALYSES AND COMPARISON OF BULK AND COIL SURFACE SAMPLES FROM THE DWPF SLURRY MIX EVAPORATOR

Sludge samples from the DWPF Slurry Mix Evaporator (SME) heating coil frame and coil surface were characterized to identify differences that might help identify heat transfer fouling materials. The SME steam coils have seen increased fouling leading to lower boil-up rates. Samples of the sludge were taken from the coil frame somewhat distant from the coil (bulk tank material) and from the coil surface (coil surface sample). The results of the analysis indicate the composition of the two SME samples are very similar with the exception that the coil surface sample shows {approx}5-10X higher mercury concentration than the bulk tank sample. Elemental analyses and x-ray diffraction results did not indicate notable differences between the two samples. The ICP-MS and Cs-137 data indicate no significant differences in the radionuclide composition of the two SME samples. Semi-volatile organic analysis revealed numerous organic molecules, these likely result from antifoaming additives. The compositions of the two SME samples also match well with the analyzed composition of the SME batch with the exception of significantly higher silicon, lithium, and boron content in the batch sample indicating the coil samples are deficient in frit relative to the SME batch composition.
Date: February 17, 2012
Creator: Hay, M.; Nash, C. & Stone, M.
System: The UNT Digital Library
Preliminary Study of the Efficacy of Using Nuclear Resonance Fluorescence with Quasi-Monoenergetic Gamma-Ray Sources for Nuclear Safeguards Assay (open access)

Preliminary Study of the Efficacy of Using Nuclear Resonance Fluorescence with Quasi-Monoenergetic Gamma-Ray Sources for Nuclear Safeguards Assay

We have studied the efficacy of using nuclear resonance fluorescence (NRF)-based techniques to assay spent nuclear fuel for Pu content using quasi-monoenergetic sources. We have developed two techniques to precisely determine the Pu content in a fuel rod/pin. One of our approaches is virtually free of systematic uncertainties. Using analytical models, we have determined the amount of time required to measure the Pu content in spent nuclear fuel rods and spent fuel assemblies to within 1% precision. We note that Pu content can be determined in a fuel assembly about as fast as in a single fuel pin. The performance of NRF-based assay techniques with improved photon sources, which are currently under development, will also estimated. For follow-on research we propose to: (1) Construct research prototype detection systems for both of the NRF-based assay systems proposed in this paper and measure their calibration curves; (2) Determine the systematic errors associated with both assay methods, explore ways to reduce the errors and fold the results into future performance calculations; (3) Develop an algorithm to assay a fuel assembly; (4) Perform validation measurements using a single pin and scaled assemblies; (5) Research and develop current-mode detection and/or threshold detection techniques to improve …
Date: February 17, 2011
Creator: Johnson, M. S.; McNabb, D. P.; Hall, J. M. & Gonzalez, J. J.
System: The UNT Digital Library
Review of APR+ Level 2 PSA (open access)

Review of APR+ Level 2 PSA

Brookhaven National Laboratory (BNL) assisted the Korea Institute of Nuclear Safety (KINS) in reviewing the Level 2 Probabilistic Safety Assessment (PSA) of the APR+ Advanced Pressurized Water Reactor (PWR) prepared by the Korea Hydro & Nuclear Power Co., Ltd (KHNP) and KEPCO Engineering & Construction Co., Inc. (KEPCO-E&amp;C). The work described in this report involves a review of the APR+ Level 2 PSA submittal [Ref. 1]. The PSA and, therefore, the review is limited to consideration of accidents initiated by internal events. As part of the review process, the review team also developed three sets of Requests for Additional Information (RAIs). These RAIs were provided to KHNP and KEPCO-E&amp;C for their evaluation and response. This final detailed report documents the review findings for each technical element of the PSA and includes consideration of all of the RAIs made by the reviewers as well as the associated responses. This final report was preceded by an interim report [Ref. 2] that focused on identifying important issues regarding the PSA. In addition, a final meeting on the project was held at BNL on November 21-22, 2011, where BNL and KINS reviewers discussed their preliminary review findings with KHNP and KEPCO-E&amp;C staffs. Additional information …
Date: February 17, 2012
Creator: Lehner, J.R.; Mubayi, V. & Pratt, W. T.
System: The UNT Digital Library
Experimental Progress Report--Modernizing the Fission Basis (open access)

Experimental Progress Report--Modernizing the Fission Basis

In 2010 a proposal (Modernizing the Fission Basis) was prepared to 'resolve long standing differences between LANL and LLNL associated with the correct fission basis for analysis of nuclear test data'. Collaboration between LANL/LLNL/TUNL has been formed to implement this program by performing high precision measurements of neutron induced fission product yields as a function of incident neutron energy. This new program benefits from successful previous efforts utilizing mono-energetic neutrons undertaken by this collaboration. The first preliminary experiment in this new program was performed between July 24-31, 2011 at TUNL and had 2 main objectives: (1) demonstrating the capability to measure characteristic {gamma}-rays from specific fission products; (2) studying background effects from room scattered neutrons. In addition, a new dual fission ionization chamber has been designed and manufactured. The production design of the chamber is shown in the picture below. The first feasibility experiment to test this chamber is scheduled at the TUNL Tandem Laboratory from September 19-25, 2011. The dual fission chamber design will allow simultaneous exposure of absolute fission fragment emission rate detectors and the thick fission activation foils, positioned between the two chambers. This document formalizes the earlier experimental report demonstrating the experimental capability to make accurate …
Date: February 17, 2012
Creator: Macri, R A
System: The UNT Digital Library
Novel Separation of Actinides (open access)

Novel Separation of Actinides

The separation of actinides and other elements of interest for nuclear forensics and threat reduction is currently performed using decades-old chemistries and ion-exchange columns. We propose to determine the technical feasibility of a novel method for separating actinide ions in solution. This method is based upon isotachophoresis (ITP), which has been applied in the purification of pharmaceuticals and other biochemical applications. This technique has the potential to separate inorganic ions more effectively than existing methods, which is key to analyzing very small samples. We will perform a quantitative assessment of the effectiveness of specific isotachophoretic approaches including predicting the physical and chemical properties, such as ion mobility, of inorganic ions under specific solvent conditions using a combination of ab initio calculations and semi-empirical methods. We expect to obtain a thorough understanding of the analytical systems parameters under which ITP is most effective for the separation of inorganic samples, including the influence of the double layer surrounding actinide ions, the Debye length for different ions and ion complexes, and Debye-Hueckel limits. Inorganic separations are key to nuclear forensics for countering terrorism and nuclear proliferation. If found to be feasible and potentially superior to currently used separation approaches, ITP could provide the …
Date: February 17, 2011
Creator: Mariella, Raymond
System: The UNT Digital Library
Geothermal Energy for New Mexico: Assessment of Potential and Exploratory Drilling (open access)

Geothermal Energy for New Mexico: Assessment of Potential and Exploratory Drilling

This report summarizes the drilling operations and subsequent interpretation of thermal and geochemical data from the New Mexico Tech NMT-2GT (OSE RG- 05276 POD) test well. This slim hole was drilled along an elongate heat-flow anomaly at the base of the Socorro Mountains to better assess the geothermal resource potential (Socorro Peak geothermal system) on the western side of the New Mexico Tech campus in Socorro, New Mexico. The reservoir depth, hydraulic properties, temperature and chemistry were unknown prior to drilling. The purpose of the NMT-2GT (OSE RG-05276 POD) well was to explore the feasibility of providing geothermal fluids for a proposed district space heating system on the New Mexico Tech campus. With DOE cost over runs funds we completed NMT-2GT to a depth of 1102 feet at the Woods Tunnel drill site. Temperatures were nearly constant (41 oC ) between a depth of 400–1102 feet. Above this isothermal zone, a strong temperature gradient was observed (210 oC /km) beneath the water table consistent with vertical convective heat transfer. The existence of a groundwater upflow zone was further supported by measured vertical hydraulic head measurements which varied between about 258 feet at the water table to 155 feet at a …
Date: February 17, 2010
Creator: Mark Person, Lara Owens, James Witcher
System: The UNT Digital Library
NW-MILO Acoustic Data Collection (open access)

NW-MILO Acoustic Data Collection

There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL’s Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hours a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight …
Date: February 17, 2010
Creator: Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R. & Jones, Mark E.
System: The UNT Digital Library
Calibration and Laboratory Test of the Department of Energy Cloud Particle Imager (open access)

Calibration and Laboratory Test of the Department of Energy Cloud Particle Imager

Calibration parameters from the Connolly et al. (2007) algorithm cannot be applied to the Department of Energy's (DOE) CPI because the DOE CPI is version 2.0. Thus, Dr. Junshik Um and Prof. Greg McFarquhar brought the DOE CPI to the University of Manchester, UK, where facilities for calibrating it were available. In addition, two other versions of CPIs (1.0 and 1.5) were available on-site at the University of Manchester so that an intercomparison of three different versions of the CPI was possible. The three CPIs (versions 1.0, 1.5, and 2.0) were calibrated by moving glass calibration beads and ice analogues of known size parallel to the object plane. The distance between the object plane and a particle, the particle's focus, its apparent maximum dimension, and a background image were measured in order to derive calibration parameters for each CPI version. The calibration parameters are used in two empirical equations that are applied to in situ CPI data to determine particle size and depth of field, and hence particle size distributions (PSDs). After the tests with the glass calibration beads to derive the calibration parameters, the three CPIs were installed at the base of the Manchester Ice Cloud Chamber and connected …
Date: February 17, 2012
Creator: McFarquhar, GM & Um, J
System: The UNT Digital Library
Pulse Jet Mixing Tests With Noncohesive Solids (open access)

Pulse Jet Mixing Tests With Noncohesive Solids

This report summarizes results from pulse jet mixing (PJM) tests with noncohesive solids in Newtonian liquid. The tests were conducted during FY 2007 and 2008 to support the design of mixing systems for the Hanford Waste Treatment and Immobilization Plant (WTP). Tests were conducted at three geometric scales using noncohesive simulants, and the test data were used to develop models predicting two measures of mixing performance for full-scale WTP vessels. The models predict the cloud height (the height to which solids will be lifted by the PJM action) and the critical suspension velocity (the minimum velocity needed to ensure all solids are suspended off the floor, though not fully mixed). From the cloud height, the concentration of solids at the pump inlet can be estimated. The predicted critical suspension velocity for lifting all solids is not precisely the same as the mixing requirement for 'disturbing' a sufficient volume of solids, but the values will be similar and closely related. These predictive models were successfully benchmarked against larger scale tests and compared well with results from computational fluid dynamics simulations. The application of the models to assess mixing in WTP vessels is illustrated in examples for 13 distinct designs and selected …
Date: February 17, 2012
Creator: Meyer, Perry A.; Bamberger, Judith A.; Enderlin, Carl W.; Fort, James A.; Wells, Beric E.; Sundaram, S. K. et al.
System: The UNT Digital Library
Energy Efficient Electronics Cooling Project (open access)

Energy Efficient Electronics Cooling Project

Parker Precision Cooling Business Unit was awarded a Department of Energy grant (DE-EE0000412) to support the DOE-ITP goal of reducing industrial energy intensity and GHG emissions. The project proposed by Precision Cooling was to accelerate the development of a cooling technology for high heat generating electronics components. These components are specifically related to power electronics found in power drives focused on the inverter, converter and transformer modules. The proposed cooling system was expected to simultaneously remove heat from all three of the major modules listed above, while remaining dielectric under all operating conditions. Development of the cooling system to meet specific customer's requirements and constraints not only required a robust system design, but also new components to support long system functionality. Components requiring further development and testing during this project included pumps, fluid couplings, cold plates and condensers. All four of these major categories of components are required in every Precision Cooling system. Not only was design a key area of focus, but the process for manufacturing these components had to be determined and proven through the system development.
Date: February 17, 2012
Creator: O'Shaughnessey, Steve; Louvar, Tim; Trumbower, Mike; Hunnicutt, Jessica & Myers, Neil
System: The UNT Digital Library
Majorana One-Tonne Cryostat Cooling Conceptual Feasibility Study (open access)

Majorana One-Tonne Cryostat Cooling Conceptual Feasibility Study

This report evaluates the conceptual plans for a one-tonne (S4) cryostat cooling design. This document is based upon previous design work and experimental results used to evaluate the current MAJORANA DEMONSTRATOR (MJD) thermal design. A feasibility study of a cooling system for S4 based on the MJD thermosyphon experiment is presented. The one-tonne experiment will be a scaled up version of the MJD. There will be many cryostats for the S4 experiment. In this document a cryostat with up to 19 strings of Germanium crystals is analyzed. Aside from an extra outer ring of crystals, the geometry of both systems’ cryostats is very similar. The materials used in the fabrication of both ultra-low background experiments will be underground electroformed copper. The current MJD uses a two-phase liquid-gas cooling system to ensure constant operating temperature. This document presents a theoretical investigation of a cooling system for the S4 experiment and evaluates the heat transfer performance requirements for such a system.
Date: February 17, 2011
Creator: Reid, Douglas J.; Orrell, John L.; Fast, James E. & Aguayo Navarrete, Estanislao
System: The UNT Digital Library