Advanced Electric Submersible Pump Design Tool for Geothermal Applications (open access)

Advanced Electric Submersible Pump Design Tool for Geothermal Applications

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
System: The UNT Digital Library
Balance of Nanostructure and Bimetallic Interactions in Pt Model Fuel Cell Catalysts: An in Situ XAS and DFT Study (open access)

Balance of Nanostructure and Bimetallic Interactions in Pt Model Fuel Cell Catalysts: An in Situ XAS and DFT Study

We have studied the effect of nanostructuring in Pt monolayer model electrocatalysts on a Rh(111) single-crystal substrate on the adsorption strength of chemisorbed species. In situ high energy resolution fluorescence detection X-ray absorption spectroscopy at the Pt L(3) edge reveals characteristic changes of the shape and intensity of the 'white-line' due to chemisorption of atomic hydrogen (H(ad)) at low potentials and oxygen-containing species (O/OH(ad)) at high potentials. On a uniform, two-dimensional Pt monolayer grown by Pt evaporation in ultrahigh vacuum, we observe a significant destabilization of both H(ad) and O/OH(ad) due to strain and ligand effects induced by the underlying Rh(111) substrate. When Pt is deposited via a wet-chemical route, by contrast, three-dimensional Pt islands are formed. In this case, strain and Rh ligand effects are balanced with higher local thickness of the Pt islands as well as higher defect density, shifting H and OH adsorption energies back toward pure Pt. Using density functional theory, we calculate O adsorption energies and corresponding local ORR activities for fcc 3-fold hollow sites with various local geometries that are present in the three-dimensional Pt islands.
Date: May 31, 2012
Creator: Friebel, Daniel; Viswanathan, Venkatasubramanian; Miller, Daniel James; Anniyev, Toyli; Ogasawara, Hirohito; Larsen, Ask Hjorth et al.
System: The UNT Digital Library
Governance of the International Linear Collider Project (open access)

Governance of the International Linear Collider Project

Governance models for the International Linear Collider Project are examined in the light of experience from similar international projects around the world. Recommendations for one path which could be followed to realize the ILC successfully are outlined. The International Linear Collider (ILC) is a unique endeavour in particle physics; fully international from the outset, it has no 'host laboratory' to provide infrastructure and support. The realization of this project therefore presents unique challenges, in scientific, technical and political arenas. This document outlines the main questions that need to be answered if the ILC is to become a reality. It describes the methodology used to harness the wisdom displayed and lessons learned from current and previous large international projects. From this basis, it suggests both general principles and outlines a specific model to realize the ILC. It recognizes that there is no unique model for such a laboratory and that there are often several solutions to a particular problem. Nevertheless it proposes concrete solutions that the authors believe are currently the best choices in order to stimulate discussion and catalyze proposals as to how to bring the ILC project to fruition. The ILC Laboratory would be set up by international treaty …
Date: May 31, 2012
Creator: Foster, B.; U., /Oxford; Barish, B.; /Caltech; Delahaye, J. P.; /CERN et al.
System: The UNT Digital Library
Beam Ion Instability in ILC Damping Ring with Multi-Gas Species (open access)

Beam Ion Instability in ILC Damping Ring with Multi-Gas Species

Ion induced beam instability is one critical issue for the electron damping ring of the International Linear Collider (ILC) due to its ultra small emittance of 2 pm. The beam ion instability with various beam filling patterns for the latest lattice DTC02 is studied using PIC code. The code has been benchmarked with SPEAR3 experimental data and there is a good agreement between the simulation and observations. It uses the optics from MAD and can handle arbitrary beam filling pattern and vacuum. Different from previous studies, multi-gas species and exact beam filling patterns have been modeled simultaneously in the study. This feature makes the study more realistic. Analyses have been done to compare with the simulations.
Date: May 30, 2012
Creator: Wang, Lanfa & Pivi, Mauro
System: The UNT Digital Library
Extension of the Bayesloc Multiple-Event Location Algorithm to Include Differential Travel Time Measurements (open access)

Extension of the Bayesloc Multiple-Event Location Algorithm to Include Differential Travel Time Measurements

None
Date: May 30, 2012
Creator: Myers, S C & Johannesson, G
System: The UNT Digital Library
ONSITE TRANSPORTATION AUTHORIZATION CHALLENGES AT THE SAVANNAH RIVER SITE (open access)

ONSITE TRANSPORTATION AUTHORIZATION CHALLENGES AT THE SAVANNAH RIVER SITE

Prior to 2008, transfers of radioactive material within the Savannah River Site (SRS) boundary, referred to as onsite transfers, were authorized by Transportation Safety Basis (TSB) documents that only required approval by the SRS contractor. This practice was in accordance with the existing SRS Transportation Safety Document (TSD). In 2008 the Department of Energy Savannah River Field Office (DOE-SR) requested that the SRS TSD be revised to require DOE-SR approval of all Transportation Safety Basis (TSB) documents. As a result, the primary SRS contractor embarked on a multi-year campaign to consolidate old or generate new TSB documents and obtain DOE-SR approval for each. This paper focuses on the challenges incurred during the rewriting or writing of and obtaining DOE-SR approval of all Savannah River Site Onsite Transportation Safety Basis documents.
Date: May 30, 2012
Creator: Watkins, R.; Loftin, B.; Hoang, D. & Maxted, M.
System: The UNT Digital Library
Optimization of the Dynamic Aperture for SPEAR3 Low-Emittance Upgrade (open access)

Optimization of the Dynamic Aperture for SPEAR3 Low-Emittance Upgrade

A low emittance upgrade is planned for SPEAR3. As the first phase, the emittance is reduced from 10nm to 7nm without additional magnets. A further upgrade with even lower emittance will require a damping wiggler. There is a smaller dynamic aperture for the lower emittance optics due to a stronger nonlinearity. Elegant based Multi-Objective Genetic Algorithm (MOGA) is used to maximize the dynamic aperture. Both the dynamic aperture and beam lifetime are optimized simultaneously. Various configurations of the sextupole magnets have been studied in order to find the best configuration. The betatron tune also can be optimized to minimize resonance effects. The optimized dynamic aperture increases more than 15% from the nominal case and the lifetime increases from 14 hours to 17 hours. It is important that the increase of the dynamic aperture is mainly in the beam injection direction. Therefore the injection efficiency will benefit from this improvement.
Date: May 30, 2012
Creator: Wang, Lanfa; Huang, Xiaobiao; Nosochkov, Yuri; Safranek, James A. & Borland, Michael
System: The UNT Digital Library
Reversible Electron Beam Heating for Suppression of Micro bunching Instabilities at Free-Electron Lasers (open access)

Reversible Electron Beam Heating for Suppression of Micro bunching Instabilities at Free-Electron Lasers

The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.
Date: May 30, 2012
Creator: Behrens, Christopher; Huang, Zhirong & Xiang, Dao
System: The UNT Digital Library
Ceramic HEPA Filter Program (open access)

Ceramic HEPA Filter Program

None
Date: May 29, 2012
Creator: Mitchell, M A; Bergman, W; Haslam, J; Brown, E P; Sawyer, S; Beaulieu, R et al.
System: The UNT Digital Library
Distinguishing Pu Metal From Pu Oxide Using Fast Neutron Counting (open access)

Distinguishing Pu Metal From Pu Oxide Using Fast Neutron Counting

We describe a method for simultaneously determining the {alpha}-ratio and k{sub eff} for fissile materials using fast neutrons. Our method is a generalization of the Hage-Cifarrelli method for determining k{sub eff} for fissile assemblies which utilizes the shape of the fast neutron spectrum. In this talk we illustrate the method using Monte Carlo simulations of the fast neutrons generated in PuO{sub 2} to calculate the fast neutron spectrum and Feynman correlations.
Date: May 29, 2012
Creator: Verbeke, J M; Chapline, G F; Nakae, L; Wurtz, R & Sheets, S
System: The UNT Digital Library
Gas-Phase Molecular Dynamics: High Resolution Spectroscopy and Collision Dynamics of Transient Species (open access)

Gas-Phase Molecular Dynamics: High Resolution Spectroscopy and Collision Dynamics of Transient Species

This research is carried out as part of the Gas-Phase Molecular Dynamics program in the Chemistry Department at Brookhaven National Laboratory. Chemical intermediates in the elementary gas-phase reactions involved in combustion chemistry are investigated by high resolution spectroscopic tools. Production, reaction, and energy transfer processes are investigated by transient, double resonance, polarization and saturation spectroscopies, with an emphasis on technique development and connection with theory, as well as specific molecular properties.
Date: May 29, 2012
Creator: Hall, G. E. & Goncharov, V.
System: The UNT Digital Library
Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics (open access)

Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics

The main goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods, and extends them to understand some important properties of materials in condensed phases and interstellar medium as well as in combustion environments.
Date: May 29, 2012
Creator: Yu, H. G. & Muckerman, J. T.
System: The UNT Digital Library
LLNL-G3Dv3: global P-wave tomography model for improved regional and teleseismic travel time prediction (open access)

LLNL-G3Dv3: global P-wave tomography model for improved regional and teleseismic travel time prediction

None
Date: May 29, 2012
Creator: Simmons, N A; Myers, S C; Johannesson, G & Matzel, E
System: The UNT Digital Library
Surface and bulk current reduction of CdZnTe via band gap engineering (open access)

Surface and bulk current reduction of CdZnTe via band gap engineering

None
Date: May 29, 2012
Creator: Voss, Lars F.; Conway, Adam M.; Nelson, Art J.; Beck, Patrick R.; Graff, Robert T; Nikolic, Rebecca J et al.
System: The UNT Digital Library
Phase Transition in BCx system under High-Pressure and High-Temperature: Synthesis of Cubic Dense BC3 Nanostructured Phase (open access)

Phase Transition in BCx system under High-Pressure and High-Temperature: Synthesis of Cubic Dense BC3 Nanostructured Phase

None
Date: May 26, 2012
Creator: Zinin, P. V.; Ming, L. C.; Ishii, H. A.; Jia, R.; Acosta, T. & Hellebrand, E.
System: The UNT Digital Library
Design of RF Feed System for Standing-Wave Accelerator Structures (open access)

Design of RF Feed System for Standing-Wave Accelerator Structures

We are investigating a standing wave accelerator structure that uses a rf feed to each individual cell. This approach minimizes rf power flow and electromagnetic energy absorbed by an rf breakdown. The objective of this work is a robust high-gradient (above 100 MV/m) X-band accelerator structure.
Date: May 25, 2012
Creator: Neilson, J.; Tantawi, S. & Dolgashev, V.
System: The UNT Digital Library
Electronic Reconstruction through the Structural and Magnetic Transitions in Detwinned NaFeAs (open access)

Electronic Reconstruction through the Structural and Magnetic Transitions in Detwinned NaFeAs

We use angle-resolved photoemission spectroscopy to study twinned and detwinned iron pnictide compound NaFeAs. Distinct signatures of electronic reconstruction are observed to occur at the structural (T{sub S}) and magnetic (T{sub SDW}) transitions. At T{sub S}, C{sub 4} rotational symmetry is broken in the form of an anisotropic shift of the orthogonal d{sub xz} and d{sub yz} bands. The magnitude of this orbital anisotropy rapidly develops to near completion upon approaching T{sub SDW}, at which temperature band folding occurs via the antiferromagnetic ordering wave vector. Interestingly, the anisotropic band shift onsetting at T{sub S} develops in such a way to enhance the nesting conditions in the C{sub 2} symmetric state, hence is intimately correlated with the long range collinear AFM order. Furthermore, the similar behaviors of the electronic reconstruction in NaFeAs and Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} suggests that this rapid development of large orbital anisotropy between T{sub S} and T{sub SDW} is likely a general feature of the electronic nematic phase in the iron pnictides, and the associated orbital fluctuations may play an important role in determining the ground state properties.
Date: May 25, 2012
Creator: Yi, M.; Lu, D. H.; Moore, R. G.; Kihou, K.; Lee, C. H.; Iyo, A. et al.
System: The UNT Digital Library
Coupling Impedance of a Periodic Array of Diaphragms (Erratum) (open access)

Coupling Impedance of a Periodic Array of Diaphragms (Erratum)

A method is presented for calculating the high-frequency longitudinal and transverse coupling impedances in a periodic array of diaphragms in a circular perfectly conducting pipe. The method is based on Weinstein's theory of diffraction of a plane electromagnetic wave on a stack of halfplanes. Using Weinstein's solution, it is shown that the problem of finding the beam field in the pipe reduces to an effective boundary condition at the radius of the diaphragms that couples the longitudinal electric field with the azimuthal magnetic one. Solving Maxwell's equations with this boundary condition leads to simple formulae for Z{sub long} and Z{sub tr}. A good agreement with a numerical solution of the problem found by other authors is demonstrated.
Date: May 24, 2012
Creator: Stupakov, G. V.
System: The UNT Digital Library
Determination of the 242Pu Branching Ratio via Alpha-Gamma Coincidence (open access)

Determination of the 242Pu Branching Ratio via Alpha-Gamma Coincidence

When the burn-up is high, the {sup 242}Pu isotopic content becomes more important. The traditional correlation method will fail. The {sup 242}Pu isotopic content in the sample plays an essential role if the neutron coincidence method is used to quantify the total amount of plutonium. In one of the earlier measurements we had a chance to measure an isotopic pure (> 99.95 %) {sup 242}Pu thick sample and realized that the difference in the branching ratio (BR) value among current nuclear data3) for the two important gamma-rays at 103.5-keV and 158.8-keV. In this study, the thick sample was counted on a 15% ORTEC safeguards type HPGe to further improve BR determination of the 159-keV gamma-ray. Furthermore, we have made a thin {sup 242}Pu sample from the thick sample and performed alpha-gamma coincidence measurements. Our preliminary gamma-ray BR results are 4.37(6) E-4, 2.79(8) E-5, and 2.25(8) E-6 for 44.9-keV, 103.5-keV, and 158.9-keV, respectively.
Date: May 24, 2012
Creator: Wang, T. F.
System: The UNT Digital Library
Low-temperature triple-alpha rate in a full three-body model (open access)

Low-temperature triple-alpha rate in a full three-body model

None
Date: May 24, 2012
Creator: Nguyen, N. B.; Nunes, F. M.; Thompson, I. J. & Brown, E. F.
System: The UNT Digital Library
LSST Camera Optics Design (open access)

LSST Camera Optics Design

The Large Synoptic Survey Telescope (LSST) uses a novel, three-mirror, telescope design feeding a camera system that includes a set of broad-band filters and three refractive corrector lenses to produce a flat field at the focal plane with a wide field of view. Optical design of the camera lenses and filters is integrated in with the optical design of telescope mirrors to optimize performance. We discuss the rationale for the LSST camera optics design, describe the methodology for fabricating, coating, mounting and testing the lenses and filters, and present the results of detailed analyses demonstrating that the camera optics will meet their performance goals.
Date: May 24, 2012
Creator: Riot, V. J.; Olivier, S.; Bauman, B.; Pratuch, S.; Seppala, L.; Gilmore, D. et al.
System: The UNT Digital Library
A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING (open access)

A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING

The Small Gram Quantity (SGQ) concept is based on the understanding that the hazards associated with the shipment of a radioactive material are directly proportional to its mass. This study describes a methodology that estimates the acceptable masses for several neutron and gamma emitting isotopes that can be shipped in a 9977 Package compliant with the Title 10 of the Code of Federal Regulations, Part 71 (10CFR71) external radiation level limits. 10CFR71.33 states that a shipping application identifies the radioactive and fissile materials at their maximum quantity and provides an evaluation demonstrating compliance with the external radiation standards. Since rather small amounts of some isotopes emit sufficiently strong radiation to produce a large external dose rate, quantifying of the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. A methodology was established for determining the dose rate for bounding mass limits for a set of isotopes in the Model 9977 Shipping Package. Calculations were performed to estimate external radiation levels using the MCNP radiation transport …
Date: May 24, 2012
Creator: Abramczyk, G.; Bellamy, S.; Nathan, S. & Loftin, B.
System: The UNT Digital Library
Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques (open access)

Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques

This poster reports progress related to photonic technologies. Specifically, the authors developed diagnostic system architecture for a Multiplexed Photonic Doppler Velocimetry (MPDV) that incorporates frequency and time-division multiplexing into existing PDV methodology to provide increased channel count. Current MPDV design increases number of data records per digitizer channel 8x, and also operates as a laser-safe (Class 3a) system. Further, they applied heterodyne interferometry to allow for direction-of-travel determination and enable high-velocity measurements (>10 km/s) via optical downshifting. They also leveraged commercially available, inexpensive and robust components originally developed for telecom applications. Proposed MPDV architectures employ only commercially available, fiber-coupled hardware.
Date: May 24, 2012
Creator: Daykin, Edward
System: The UNT Digital Library
Rapid Determination Of Radiostrontium In Large Soil Samples (open access)

Rapid Determination Of Radiostrontium In Large Soil Samples

A new method for the determination of radiostrontium in large soil samples has been developed at the Savannah River Environmental Laboratory (Aiken, SC, USA) that allows rapid preconcentration and separation of strontium in large soil samples for the measurement of strontium isotopes by gas flow proportional counting. The need for rapid analyses in the event of a Radiological Dispersive Device (RDD) or Improvised Nuclear Device (IND) event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. The method employs a novel pre-concentration step that utilizes an iron hydroxide precipitation (enhanced with calcium phosphate) followed by a final calcium fluoride precipitation to remove silicates and other matrix components. The pre-concentration steps, in combination with a rapid Sr Resin separation using vacuum box technology, allow very large soil samples to be analyzed for {sup 89,90}Sr using gas flow proportional counting with a lower method detection limit. The calcium fluoride precipitation eliminates column flow problems typically associated with large amounts of silicates in large soil samples.
Date: May 24, 2012
Creator: Maxwell, Sherrod L.; Culligan, Brian K. & Shaw, Patrick J.
System: The UNT Digital Library