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Design and Development of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

Description: The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication.
Date: July 1, 2012
Creator: Payagalage Subashini Uddi De Silva, Jean Delayen
Partner: UNT Libraries Government Documents Department

CONTROL OF NONLINEAR DYNAMICS BY ACTIVE AND PASSIVE METHODS FOR THE NSLS-II INSERTION DEVICES

Description: Nonlinear effects from insertion devices are potentially a limiting factor for the electron beam quality of modern ring-based light sources, i.e., the on and off-dynamical aperture, leading to reduced injection efficiency and beam lifetime. These effects can be modelled by e.g. kick maps ({approx}1/{gamma}{sup 2}) and controlled by e.g. first-order thin or thick magnetic kicks introduced by 'magic fingers,' 'L-shims,' or 'current strips'. However, due to physical or technological constraints, these corrections are typically only partial. Therefore, a precise model is needed to correctly minimize the residual nonlinear effects for the entire system. We outline a systematic method for integrated design and rapid prototyping based on evaluation of the 3D magnetic field and control of the local trajectory with RADIA, and particle tracking with Tracy-3 for validation. The optimal geometry for the compensating magnetic fields is determined from the results of these simulations using a combination of linear algebra and genetic optimization.
Date: May 20, 2012
Creator: J., Bengtsson; Chubar, O.; Kitegi, C. & Tanabe, T.
Partner: UNT Libraries Government Documents Department

Experimental Evaluation of Multi-spacecraft Data Analysis Techniques in a Laboratory Plasma

Description: The Magnetic Reconnection Experiment (MRX)[1] has been utilized to assess the effectiveness of minimum variance analysis on the magnetic field (MVAB) and boundary-crossing time analysis (BCTA). The neutral sheet is swept, or jogged, in a controlled manner with respect to the stationary probes by pulsed internal coil currents. Magnetic field data from measurement points resembling data from multi-spacecraft flying though a reconnecting current sheet is used to check both techniques to deduce a proper normal vector. We examine discharges with the two-dimensional (2-D) X-line structure as well as cases in which a flux rope forms within the layer. All discharges are in a two-fluid regime in which electrons are magnetized but not ions. Boundary-crossing time analysis with four sample measurement points forming a tetrahedron generates a reasonable unit normal vector and relative velocity along the normal vector for all of the tested cases. On the other hand, MVAB sometimes fails to predict a proper normal direction. This is because the X-line magnetic geometry is fundamentally 2-D or 3-D. However, the direction along the reconnecting field determined by MVAB does not deviate much from the real magnetic geometry documented by 2-D magnetic probe arrays and one additional probe at a different toroidal location. Based on these observations, we suggest a procedure for determining a local coordinate system for data from the Magnetospheric Multi-Scale (MMS) mission when spacecraft passes through a reconnecting current sheet. The distance between measurement points on the order of the ion skin depth (c/{omega}{sub pi}) is pertinent to determination of the magnetic geometry.
Date: March 27, 2012
Creator: Yamada, Jongsoo Yoo and Masaaki
Partner: UNT Libraries Government Documents Department

Characteristics and fabrication of a 499 MHz superconducting deflecting cavity for the Jefferson Lab 12 geV Upgrade

Description: A 499 MHz parallel bar superconducting deflecting cavity has been designed and optimized for a possible implementation at the Jefferson Lab. Previously the mechanical analysis, mainly stress, was performed. Since then pressure sensitivity was studied further and the cavity parts were fabricated. The prototype cavity is not completed due to the renovation at Jefferson Lab which resulted in the temporary shutdown of the electron beam welding facility. This paper will present the analysis results and facts encountered during fabrication. The unique geometry of the cavity and its required mechanical strength present interesting manufacturing challenges.
Date: July 1, 2012
Creator: HyeKyoung Park, S.U. De Silva, J.R. Delayen
Partner: UNT Libraries Government Documents Department

Power distributions in fresh and depleted LEU and HEU cores of the MITR reactor.

Description: The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. It delivers a neutron flux comparable to current LWR power reactors in a compact 6 MW core using Highly Enriched Uranium (HEU) fuel. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context, most research and test reactors both domestic and international have started a program of conversion to the use of Low Enriched Uranium (LEU) fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (UMo) is expected to allow the conversion of U.S. domestic high performance reactors like the MITR-II reactor. Toward this goal, core geometry and power distributions are presented. Distributions of power are calculated for LEU cores depleted with MCODE using an MCNP5 Monte Carlo model. The MCNP5 HEU and LEU MITR models were previously compared to experimental benchmark data for the MITR-II. This same model was used with a finer spatial depletion in order to generate power distributions for the LEU cores. The objective of this work is to generate and characterize a series of fresh and depleted core peak power distributions, and provide a thermal hydraulic evaluation of the geometry which should be considered for subsequent thermal hydraulic safety analyses.
Date: April 4, 2012
Creator: Wilson, E.H.; Horelik, N.E.; Dunn, F.E.; Newton, T.H., Jr.; Hu, L.; Stevens, J.G. (Nuclear Engineering Division) et al.
Partner: UNT Libraries Government Documents Department

FY2012 summary of tasks completed on PROTEUS-thermal work.

Description: PROTEUS is a suite of the neutronics codes, both old and new, that can be used within the SHARP codes being developed under the NEAMS program. Discussion here is focused on updates and verification and validation activities of the SHARP neutronics code, DeCART, for application to thermal reactor analysis. As part of the development of SHARP tools, the different versions of the DeCART code created for PWR, BWR, and VHTR analysis were integrated. Verification and validation tests for the integrated version were started, and the generation of cross section libraries based on the subgroup method was revisited for the targeted reactor types. The DeCART code has been reorganized in preparation for an efficient integration of the different versions for PWR, BWR, and VHTR analysis. In DeCART, the old-fashioned common blocks and header files have been replaced by advanced memory structures. However, the changing of variable names was minimized in order to limit problems with the code integration. Since the remaining stability problems of DeCART were mostly caused by the CMFD methodology and modules, significant work was performed to determine whether they could be replaced by more stable methods and routines. The cross section library is a key element to obtain accurate solutions. Thus, the procedure for generating cross section libraries was revisited to provide libraries tailored for the targeted reactor types. To improve accuracy in the cross section library, an attempt was made to replace the CENTRM code by the MCNP Monte Carlo code as a tool obtaining reference resonance integrals. The use of the Monte Carlo code allows us to minimize problems or approximations that CENTRM introduces since the accuracy of the subgroup data is limited by that of the reference solutions. The use of MCNP requires an additional set of libraries without resonance cross sections so that reference ...
Date: June 6, 2012
Creator: Lee, C.H. & Smith, M.A. (Nuclear Engineering Division)
Partner: UNT Libraries Government Documents Department

Representing Range Compensators with Computational Geometry in TOPAS

Description: In a proton therapy beamline, the range compensator modulates the beam energy, which subsequently controls the depth at which protons deposit energy. In this paper, we introduce two computational representations of range compensator. One of our compensator representations, which we refer to as a subtraction solid-based range compensator, precisely represents the compensator. Our other representation, the 3D hexagon-based range compensator, closely approximates the compensator geometry. We have implemented both of these compensator models in a proton therapy Monte Carlo simulation called TOPAS (Tool for Particle Simulation). In the future, we will present a detailed study of the accuracy and runtime performance trade-offs between our two range compensator representations.
Date: September 7, 2012
Creator: Iandola, Forrest N. & /Illinois U., Urbana /SLAC
Partner: UNT Libraries Government Documents Department

Resolving Lifshitz Horizons

Description: Via the AdS/CFT correspondence, ground states of field theories at finite charge density are mapped to extremal black brane solutions. Studies of simple gravity + matter systems in this context have uncovered wide new classes of extremal geometries. The Lifshitz metrics characterizing field theories with non-trivial dynamical critical exponent z {ne} 1 emerge as one common endpoint in doped holographic toy models. However, the Lifshitz horizon exhibits mildly singular behaviour - while curvature invariants are finite, there are diverging tidal forces. Here we show that in some of the simplest contexts where Lifshitz metrics emerge, Einstein-Maxwell-dilaton theories, generic corrections lead to a replacement of the Lifshitz metric, in the deep infrared, by a re-emergent AdS{sub 2} x R{sup 2} geometry. Thus, at least in these cases, the Lifshitz scaling characterizes the physics over a wide range of energy scales, but the mild singularity is cured by quantum or stringy effects.
Date: April 24, 2012
Creator: Harrison, Sarah; Kachru, Shamit; Wang, Huajia & /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC
Partner: UNT Libraries Government Documents Department

A Full-wave Model for Wave Propagation and Dissipation in the Inner Magnetosphere Using the Finite Element Method

Description: A wide variety of plasma waves play an important role in the energization and loss of particles in the inner magnetosphere. Our ability to understand and model wave-particle interactions in this region requires improved knowledge of the spatial distribution and properties of these waves as well as improved understanding of how the waves depend on changes in solar wind forcing and/or geomagnetic activity. To this end, we have developed a two-dimensional, finite element code that solves the full wave equations in global magnetospheric geometry. The code describes three-dimensional wave structure including mode conversion when ULF, EMIC, and whistler waves are launched in a two-dimensional axisymmetric background plasma with general magnetic field topology. We illustrate the capabilities of the code by examining the role of plasmaspheric plumes on magnetosonic wave propagation; mode conversion at the ion-ion and Alfven resonances resulting from external, solar wind compressions; and wave structure and mode conversion of electromagnetic ion cyclotron waves launched in the equatorial magnetosphere, which propagate along the magnetic field lines toward the ionosphere. We also discuss advantages of the finite element method for resolving resonant structures, and how the model may be adapted to include nonlocal kinetic effects.
Date: March 13, 2012
Creator: Valeo, Ernest; Johnson, Jay R.; Eun-Hwa & Phillips, Cynthia
Partner: UNT Libraries Government Documents Department

Status of High Power Tests of Normal Conducting Single-Cell Standing Wave Structures

Description: Our experiments are directed toward the understanding of the physics of rf breakdown in systems that can be used to accelerate electron beams at {approx}11.4 GHz. The structure geometries have apertures, stored energy per cell, and rf pulse duration close to that of the NLC or CLIC. The breakdown rate is the main parameter that we use to compare rf breakdown behavior for different structures at a given set of rf pulse parameters (pulse shape and peak power) at 60 Hz repetition rate. In our experiments, the typical range of the breakdown rate is from one per few hours to {approx}100 per hour. To date we have tested 29 structures. We consistently found that after the initial conditioning, the behavior of the breakdown rate is reproducible for structures of the same geometry and material, and the breakdown rate dependence on peak magnetic fields is stronger than on peak surface electric fields for structures of different geometries. Below we report the main results from tests of seven structures made from hard copper, soft copper alloys and hard-copper alloys. Additional details on these and other structures will be discussed in future publications.
Date: June 25, 2012
Creator: Dolgashev, Valery; /SLAC; Tantawi, Sami; /SLAC; Yeremian, Anahid; /SLAC et al.
Partner: UNT Libraries Government Documents Department

Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cyromodule

Description: A single-cell superconducting deflecting cavity operating at 2.815 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source (APS) upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the LOM/HOM below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOM above the beampipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially be trapped between the cavities which could produce RF heating to the beamline bellows. We have evaluated the HOM damping in the 4-cavity cryomodule using the parallel finite element EM code suite ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.
Date: June 6, 2012
Creator: Xiao, L; Li, Z.; Ng, C.; /SLAC; Nassiri, A.; Waldschmidt, G. et al.
Partner: UNT Libraries Government Documents Department

RELAP5-3D Results for Phase I (Exercise 2) of the OECD/NEA MHTGR-350 MW Benchmark

Description: The coupling of the PHISICS code suite to the thermal hydraulics system code RELAP5-3D has recently been initiated at the Idaho National Laboratory (INL) to provide a fully coupled prismatic Very High Temperature Reactor (VHTR) system modeling capability as part of the NGNP methods development program. The PHISICS code consists of three modules: INSTANT (performing 3D nodal transport core calculations), MRTAU (depletion and decay heat generation) and a perturbation/mixer module. As part of the verification and validation activities, steady state results have been obtained for Exercise 2 of Phase I of the newly-defined OECD/NEA MHTGR-350 MW Benchmark. This exercise requires participants to calculate a steady-state solution for an End of Equilibrium Cycle 350 MW Modular High Temperature Reactor (MHTGR), using the provided geometry, material, and coolant bypass flow description. The paper provides an overview of the MHTGR Benchmark and presents typical steady state results (e.g. solid and gas temperatures, thermal conductivities) for Phase I Exercise 2. Preliminary results are also provided for the early test phase of Exercise 3 using a two-group cross-section library and the Relap5-3D model developed for Exercise 2.
Date: June 1, 2012
Creator: Strydom, Gerhard
Partner: UNT Libraries Government Documents Department

New Fabrication Method Improves the Efficiency and Economics of Solar Cells (Fact Sheet)

Description: Synthetic fabrication strategy optimizes the illumination geometry and transport properties of dye-sensitized solar cells. Using oriented titanium oxide (TiO{sub 2}) nanotube (NT) arrays has shown promise for dye-sensitized solar cells (DSSCs). High solar conversion efficiency requires that the incident light enters the cell from the photoelectrode side. However, for NT-based DSSCs, the light normally enters the cell through the counter electrode because a nontransparent titanium foil is typically used as the substrate for forming the aligned NTs and for making electrical contact with them. It has been synthetically challenging to prepare transparent TiO{sub 2} NT electrodes by directly anodizing Ti metal films on transparent conducting oxide (TCO) substrates because it is difficult to control the synthetic conditions. National Renewable Energy Laboratory (NREL) researchers have developed a general synthetic strategy for fabricating transparent TiO{sub 2} NT films on TCO substrates. With the aid of a conducting Nb-doped TiO{sub 2} (NTO) layer between the Ti film and TCO substrate, the Ti film can be anodized completely without degrading the TCO. The NTO layer protects the TCO from degradation through a self-terminating mechanism by arresting the electric field-assisted dissolution process at the NT-NTO interface. NREL researchers found that the illumination direction and wavelength of the light incident on the DSSCs strongly influenced the incident photon-to-current conversion efficiency, light-harvesting, and charge-collection properties, which, in turn, affect the photocurrent density, photovoltage, and solar energy conversion efficiency. Researchers also examined the effects of NT film thickness on the properties and performance of DSSCs and found that illuminating the cell from the photoelectrode side substantially increased the conversion efficiency compared with illuminating it from the counter-electrode side. This method solves a key challenge in fabricating NT-based DSSCs and determines an optimal illumination direction to use in these cells. The synthetic fabrication strategy will improve the economics and ...
Date: July 1, 2012
Partner: UNT Libraries Government Documents Department

Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cryomodule

Description: A single-cell superconducting deflecting cavity operating at 2.812 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the HOM/LOM modes below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOMs above beam pipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially trapped modes between the cavities which could produce RF heating to the beamline bellows and even be detrimental to the beam. We have evaluated the HOM damping and trapped modes in the 4-cavity cryomodule using the parallel finite element EM code ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.
Date: July 1, 2012
Creator: Xiao, L.; Li, Z.; Ng, C.-K.; Nassiri, A.; Waldschmidt, G.; Wu, G. et al.
Partner: UNT Libraries Government Documents Department

RELAP5 Application to Accident Analysis of the NIST Research Reactor

Description: Detailed safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The time-dependent analysis of the primary system is determined with a RELAP5 transient analysis model that includes the reactor vessel, the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. A post-processing of the simulation results has been conducted to evaluate minimum critical heat flux ratio (CHFR) using the Sudo-Kaminaga correlation. Evaluations are performed for the following accidents: (1) the control rod withdrawal startup accident and (2) the maximum reactivity insertion accident. In both cases the RELAP5 results indicate that there is adequate margin to CHF and no damage to the fuel will occur because of sufficient coolant flow through the fuel channels and the negative scram reactivity insertion.
Date: March 18, 2012
Creator: Baek, J.; Cuadra Gascon, A.; Cheng, L.Y. & Diamond, D.
Partner: UNT Libraries Government Documents Department

DX magnet requirements for p-Au operation

Description: This document addresses the question of moving the DX magnets for p-Au operations. First the beam geometry is addressed. Next, the beam sizes are covered. Finally, a conclusion is presented.
Date: January 19, 2012
Creator: Tepikian, S.; Trbojevic&#44 & D.
Partner: UNT Libraries Government Documents Department

Experimental techniques for measuring Rayleigh-Taylor instability in inertial confinement fusion (ICF)

Description: Rayleigh-Taylor (RT) instability is one of the major concerns in inertial confinement fusion (ICF) because it amplifies target modulations in both acceleration and deceleration phases of implosion, which leads to shell disruption and performance degradation of imploding targets. This article reviews experimental results of the RT growth experiments performed on OMEGA laser system, where targets were driven directly with laser light. RT instability was studied in the linear and nonlinear regimes. The experiments were performed in acceleration phase, using planar and spherical targets, and in deceleration phase of spherical implosions, using spherical shells. Initial target modulations consisted of 2-D pre-imposed modulations, and 2-D and 3-D modulations imprinted on targets by the non-uniformities in laser drive. In planar geometry, the nonlinear regime was studied using 3-D modulations with broadband spectra near nonlinear saturation levels. In acceleration-phase, the measured modulation Fourier spectra and nonlinear growth velocities are in good agreement with those predicted by Haan's model [Haan S W 1989 Phys. Rev. A 39 5812]. In a real-space analysis, the bubble merger was quantified by a self-similar evolution of bubble size distributions [Oron D et al 2001 Phys. Plasmas 8, 2883]. The 3-D, inner-surface modulations were measured to grow throughout the deceleration phase of spherical implosions. RT growth rates are very sensitive to the drive conditions, therefore they can be used to test and validate drive physics in hydrodynamic codes used to design ICF implosions. Measured growth rates of pre-imposed 2-D target modulations below nonlinear saturation levels were used to validate non-local thermal electron transport model in laser-driven experiments.
Date: June 7, 2012
Creator: Smalyuk, V A
Partner: UNT Libraries Government Documents Department

Advanced Electric Submersible Pump Design Tool for Geothermal Applications

Description: Electrical Submersible Pumps (ESPs) present higher efficiency, larger production rate, and can be operated in deeper wells than the other geothermal artificial lifting systems. Enhanced Geothermal Systems (EGS) applications recommend lifting 300 C geothermal water at 80kg/s flow rate in a maximum 10-5/8-inch diameter wellbore to improve the cost-effectiveness. In this paper, an advanced ESP design tool comprising a 1D theoretical model and a 3D CFD analysis has been developed to design ESPs for geothermal applications. Design of Experiments was also performed to optimize the geometry and performance. The designed mixed-flow type centrifugal impeller and diffuser exhibit high efficiency and head rise under simulated EGS conditions. The design tool has been validated by comparing the prediction to experimental data of an existing ESP product.
Date: May 31, 2012
Creator: Qi, Xuele; Turnquist, Norman & Ghasripoor, Farshad
Partner: UNT Libraries Government Documents Department

Preconditioner and convergence study for the Quantum Computer Aided Design (QCAD) nonlinear poisson problem posed on the Ottawa Flat 270 design geometry.

Description: A numerical study aimed to evaluate different preconditioners within the Trilinos Ifpack and ML packages for the Quantum Computer Aided Design (QCAD) non-linear Poisson problem implemented within the Albany code base and posed on the Ottawa Flat 270 design geometry is performed. This study led to some new development of Albany that allows the user to select an ML preconditioner with Zoltan repartitioning based on nodal coordinates, which is summarized. Convergence of the numerical solutions computed within the QCAD computational suite with successive mesh refinement is examined in two metrics, the mean value of the solution (an L{sup 1} norm) and the field integral of the solution (L{sup 2} norm).
Date: May 1, 2012
Creator: Kalashnikova, Irina
Partner: UNT Libraries Government Documents Department

A Maximally Supersymmetric Kondo Model

Description: 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 distribution.
Date: February 17, 2012
Creator: Harrison, Sarah; Kachru, Shamit; Torroba, Gonzalo & /Stanford U., Phys. Dept. /SLAC
Partner: UNT Libraries Government Documents Department

A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector

Description: The principle objective of this proposal is to develop a positron emission tomography (PET) detector with depth-of-interaction (DOI) positioning capability that will achieve state of the art spatial resolution and sensitivity performance for small animal PET imaging. When arranged in a ring or box detector geometry, the proposed detector module will support <1 mm3 image resolution and >15% absolute detection efficiency. The detector will also be compatible with operation in a MR scanner to support simultaneous multi-modality imaging. The detector design will utilize a thick, monolithic crystal scintillator readout by a two-dimensional array of silicon photomultiplier (SiPM) devices using a novel sensor on the entrance surface (SES) design. Our hypothesis is that our single-ended readout SES design will provide an effective DOI positioning performance equivalent to more expensive dual-ended readout techniques and at a significantly lower cost. Our monolithic crystal design will also lead to a significantly lower cost system. It is our goal to design a detector with state of the art performance but at a price point that is affordable so the technology can be disseminated to many laboratories. A second hypothesis is that using SiPM arrays, the detector will be able to operate in a MR scanner without any degradation in performance to support simultaneous PET/MR imaging. Having a co-registered MR image will assist in radiotracer localization and may also be used for partial volume corrections to improve radiotracer uptake quantitation. The far reaching goal of this research is to develop technology for medical research that will lead to improvements in human health care.
Date: March 6, 2012
Creator: Miyaoka, Robert S
Partner: UNT Libraries Government Documents Department

Methods for Quantifying Shallow-Water Habitat Availability in the Missouri River

Description: As part of regulatory requirements for shallow-water habitat (SWH) restoration, the U.S. Army Corps of Engineers (USACE) completes periodic estimates of the quantity of SWH available throughout the lower 752 mi of the Missouri River. To date, these estimates have been made by various methods that consider only the water depth criterion for SWH. The USACE has completed estimates of SWH availability based on both depth and velocity criteria at four river bends (hereafter called reference bends), encompassing approximately 8 river miles within the lower 752 mi of the Missouri River. These estimates were made from the results of hydraulic modeling of water depth and velocity throughout each bend. Hydraulic modeling of additional river bends is not expected to be completed for deriving estimates of available SWH. Instead, future estimates of SWH will be based on the water depth criterion. The objective of this project, conducted by the Pacific Northwest National Laboratory for the USACE Omaha District, was to develop geographic information system methods for estimating the quantity of available SWH based on water depth only. Knowing that only a limited amount of water depth and channel geometry data would be available for all the remaining bends within the lower 752 mi of the Missouri River, the intent was to determine what information, if any, from the four reference bends could be used to develop methods for estimating SWH at the remaining bends. Specifically, we examined the relationship between cross-section channel morphology and relative differences between SWH estimates based on combined depth and velocity criteria and the depth-only criterion to determine if a correction factor could be applied to estimates of SWH based on the depth-only criterion. In developing these methods, we also explored the applicability of two commonly used geographic information system interpolation methods (TIN and ANUDEM) for estimating ...
Date: April 9, 2012
Creator: Hanrahan, Timothy P. & Larson, Kyle B.
Partner: UNT Libraries Government Documents Department

Adding a MOAB Geometry Interface to SHARP Structural Mechanics

Description: The authors briefly summarize the development of, and test experience with, an initial data interface between the structural mechanics code Diablo and the SHARP reactor simulation system data hub MOAB. That interface has been exercised both to write MOAB databases from Diablo, and then also to use such a database to read in part of a simulation definition for a subsequent Diablo execution. All enhancements are integrated into the central Diablo source repository. The SHARP software system for advanced simulation of nuclear reactors and power plant systems is sponsored by DOE's Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. SHARP has been architected as a federation of single-physics simulation tools to permit flexibility in programming langugages and leveraging of past and on-going investments. Solution of multi-physics problems will be coordinated by, and data passed through, a central 'hub'. SHARP's hub implementation is utilizing MOAB: a Mesh-Oriented datABase. This same data hub approach is also intended to enable multi-resolution simulations, e.g, lower-dimension plant-scale simulations can be informed by high-fidelity 3D models of particular critical components.
Date: May 28, 2012
Creator: Ferencz, R M & Hodge, N E
Partner: UNT Libraries Government Documents Department