Advanced Coal Wind Hybrid: Economic Analysis (open access)

Advanced Coal Wind Hybrid: Economic Analysis

Growing concern over climate change is prompting new thinking about the technologies used to generate electricity. In the future, it is possible that new government policies on greenhouse gas emissions may favor electric generation technology options that release zero or low levels of carbon emissions. The Western U.S. has abundant wind and coal resources. In a world with carbon constraints, the future of coal for new electrical generation is likely to depend on the development and successful application of new clean coal technologies with near zero carbon emissions. This scoping study explores the economic and technical feasibility of combining wind farms with advanced coal generation facilities and operating them as a single generation complex in the Western US. The key questions examined are whether an advanced coal-wind hybrid (ACWH) facility provides sufficient advantages through improvements to the utilization of transmission lines and the capability to firm up variable wind generation for delivery to load centers to compete effectively with other supply-side alternatives in terms of project economics and emissions footprint. The study was conducted by an Analysis Team that consists of staff from the Lawrence Berkeley National Laboratory (LBNL), National Energy Technology Laboratory (NETL), National Renewable Energy Laboratory (NREL), and …
Date: November 28, 2008
Creator: Phadke, Amol; Goldman, Charles; Larson, Doug; Carr, Tom; Rath, Larry; Balash, Peter et al.
Object Type: Report
System: The UNT Digital Library
Communication Requirements and Interconnect Optimization forHigh-End Scientific Applications (open access)

Communication Requirements and Interconnect Optimization forHigh-End Scientific Applications

The path towards realizing peta-scale computing isincreasingly dependent on building supercomputers with unprecedentednumbers of processors. To prevent the interconnect from dominating theoverall cost of these ultra-scale systems, there is a critical need forhigh-performance network solutions whose costs scale linearly with systemsize. This work makes several unique contributions towards attaining thatgoal. First, we conduct one of the broadest studies to date of high-endapplication communication requirements, whose computational methodsinclude: finite-difference, lattice-bolzmann, particle in cell, sparselinear algebra, particle mesh ewald, and FFT-based solvers. Toefficiently collect this data, we use the IPM (Integrated PerformanceMonitoring) profiling layer to gather detailed messaging statistics withminimal impact to code performance. Using the derived communicationcharacterizations, we next present fit-trees interconnects, a novelapproach for designing network infrastructure at a fraction of thecomponent cost of traditional fat-tree solutions. Finally, we propose theHybrid Flexibly Assignable Switch Topology (HFAST) infrastructure, whichuses both passive (circuit) and active (packet) commodity switchcomponents to dynamically reconfigure interconnects to suit thetopological requirements of scientific applications. Overall ourexploration leads to a promising directions for practically addressingthe interconnect requirements of future peta-scale systems.
Date: November 12, 2007
Creator: Kamil, Shoaib; Oliker, Leonid; Pinar, Ali & Shalf, John
Object Type: Article
System: The UNT Digital Library
SUSY Les Houches Accord 2 (open access)

SUSY Les Houches Accord 2

The Supersymmetry Les Houches Accord (SLHA) [1] provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalizations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavor, as well as the simplest next-to-minimal model.
Date: November 8, 2007
Creator: Allanach, B.; Balazs, C.; Belanger, G.; Bernhardt, M.; Boudjema, F.; Choudhury, D. et al.
Object Type: Article
System: The UNT Digital Library
A HAMILTONIAN FORMULATION FOR SPIRAL-SECTOR ACCELERATORS. (open access)

A HAMILTONIAN FORMULATION FOR SPIRAL-SECTOR ACCELERATORS.

I develop a formulation for Hamiltonian dynamics in an accelerator with magnets whose edges follow a spiral. I demonstrate using this Hamiltonian that a spiral FFAG can be made perfectly 'scaling'. I examine the effect of tilting an RF cavity with respect a radial line from the center of the machine, potentially with a different angle than the spiral of the magnets.
Date: November 5, 2007
Creator: Berg, J. S.
Object Type: Article
System: The UNT Digital Library
Kaluza-Klein Dark Matter: Direct Detection vis-a-vis LHC (open access)

Kaluza-Klein Dark Matter: Direct Detection vis-a-vis LHC

We explore the phenomenology of Kaluza-Klein (KK) dark matter in very general models with universal extra dimensions (UEDs), emphasizing the complementarity between high-energy colliders and dark matter direct detection experiments. In models with relatively small mass splittings between the dark matter candidate and the rest of the (colored) spectrum, the collider sensitivity is diminished, but direct detection rates are enhanced. UEDs provide a natural framework for such mass degeneracies. We consider both 5-dimensional and 6-dimensional non-minimal UED models, and discuss the detection prospects for various KK dark matter candidates: the KK photon {gamma}{sub 1} (5D) the KK Z-boson Z{sub 1} (5D) and the spinless KK photon {gamma}{sub H} (6D). We combine collider limits such as electroweak precision data and expected LHC reach, with cosmological constraints from WMAP and the sensitivity of current or planned direct detection experiments. Allowing for general mass splittings, we show that neither colliders, nor direct detection experiments by themselves can explore all of the relevant KK dark matter parameter space. Nevertheless, they probe different parameter space regions and the combination of the two types of constraints can be quite powerful. For example, in the case of {gamma}{sub 1} in 5D UEDs the relevant parameter space will …
Date: November 1, 2008
Creator: Arrenberg, Sebastian; Baudis, Laura; Kong, Kyoungchul; Matchev, Konstantin T. & Yoo, Jonghee
Object Type: Article
System: The UNT Digital Library
Sensitivity of CO2 migration estimation on reservoir temperature and pressure uncertainty (open access)

Sensitivity of CO2 migration estimation on reservoir temperature and pressure uncertainty

The density and viscosity of supercritical CO{sub 2} are sensitive to pressure and temperature (PT) while the viscosity of brine is sensitive primarily to temperature. Oil field PT data in the vicinity of WESTCARB's Phase III injection pilot test site in the southern San Joaquin Valley, California, show a range of PT values, indicating either PT uncertainty or variability. Numerical simulation results across the range of likely PT indicate brine viscosity variation causes virtually no difference in plume evolution and final size, but CO{sub 2} density variation causes a large difference. Relative ultimate plume size is almost directly proportional to the relative difference in brine and CO{sub 2} density (buoyancy flow). The majority of the difference in plume size occurs during and shortly after the cessation of injection.
Date: November 1, 2008
Creator: Jordan, Preston & Doughty, Christine
Object Type: Article
System: The UNT Digital Library
Design Study for a Low-enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2007 (open access)

Design Study for a Low-enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2007

This report documents progress made during fiscal year 2007 in studies of converting the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) fuel to low enriched uranium fuel (LEU). Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. A high volume fraction U/Mo-in-Al fuel could attain the same neutron flux performance as with the current, HEU fuel but materials considerations appear to preclude production and irradiation of such a fuel. A diffusion barrier would be required if Al is to be retained as the interstitial medium and the additional volume required for this barrier would degrade performance. Attaining the high volume fraction (55 wt. %) of U/Mo assumed in the computational study while maintaining the current fuel plate acceptance level at the fuel manufacturer is unlikely, i.e. no increase in the percentage of plates rejected for non-compliance with the fuel specification. Substitution of a zirconium alloy for Al would significantly increase the weight of the fuel element, the cost of the fuel element, and introduce an as-yet untried manufacturing process. A monolithic U-10Mo foil is the choice of LEU fuel for HFIR. Preliminary calculations indicate that with a …
Date: November 1, 2007
Creator: Primm, Trent; Ellis, Ronald James; Gehin, Jess C; Ilas, Germina; Miller, James Henry & Sease, John D
Object Type: Report
System: The UNT Digital Library
Task Group 7B: Cellular and Molecular Mechanisms of Biological Aging: The Roles of Nature, Nurture and Chance in the Maintenance of Human Healthspan (open access)

Task Group 7B: Cellular and Molecular Mechanisms of Biological Aging: The Roles of Nature, Nurture and Chance in the Maintenance of Human Healthspan

The degree to which an individual organism maintains healthspan and lifespan is a function of complex interactions between genetic inheritance ('nature'), environment, including cultural inheritance (nurture) and stochastic events ('luck' or 'chance'). This task group will focus upon the role of chance because it is so poorly understood and because it appears to be of major importance in the determination of individual variations in healthspan and lifespan within species. The major factor determining variations in healthspan and lifespan between species is genetic inheritance. Broader aspects of cellular and molecular mechanisms of biological aging will also be considered, given their importance for understanding the cellular and molecular basis of successful aging. The task force will consider the cellular and molecular basis for nature, nurture and chance in healthspan and life span determination. On the basis of comparisons between identical and non-identical twins, geneticists have estimated that genes control no more than about a quarter of the inter-individual differences in lifespan (Herskind 1996). Twin studies of very old individuals, however, show substantially greater genetic contributions to Healthspan (McClearn 2004; Reed 2003). The environment clearly plays an important role in the length and the quality of life. Tobacco smoke, for example has the …
Date: November 14, 2007
Creator: Weier, Heinz-Ulrich; Arya, Suresh; Grant, Christine; Miller, Linda; Ono, Santa Jeremy; Patil, Chris et al.
Object Type: Article
System: The UNT Digital Library
SYNTHESIS OF METAL HYDRIDES BY MECHANICAL ALLOYING IN AN ATTRITOR MILL: FY07 STATUS REPORT (open access)

SYNTHESIS OF METAL HYDRIDES BY MECHANICAL ALLOYING IN AN ATTRITOR MILL: FY07 STATUS REPORT

The objective of this task was to demonstrate that metal hydrides could be produced by mechanical alloying in the quantities needed to support the tritium production facilities at the Savannah River Site. The objective for the FY07 portion of this task was to demonstrate the production of Zr-Fe getter materials by mechanical alloying and begin to optimize the milling parameters. Three starting compositions (ratios of elemental Zr and Fe powders) were selected and attritor milled under argon for times of 8 to 60 hours. Hexane and liquid nitrogen were used as process control agents. In general, milling times of at least 24 hours were required to form the desired Zr{sub 2}Fe and Zr{sub 3}Fe phases, although a considerable amount of unalloyed Zr and Fe remained. Milling in liquid nitrogen does not appear to provide any advantages over milling in hexane, particularly due to the formation of ZrN after longer milling times. Carbides of Zr formed during some of the milling experiments in hexane. Formation of carbides during milling appears to be much less of an issue than formation of nitrides, although some of the phases that were not able to be identified in the XRD results may also be carbides. …
Date: November 8, 2007
Creator: Fox, K
Object Type: Report
System: The UNT Digital Library
Comparison of observed and theoretical Fe L emission from CIE plasmas (open access)

Comparison of observed and theoretical Fe L emission from CIE plasmas

We analyze data from the Lawrence Livermore National Lab (LLNL) Electron Beam Ion Trap (EBIT) that simulates a CIE plasma by sweeping the electron beam to approximate a Maxwellian velocity distribution. These results are compared to spectra of confirmed astronomical CIE plasmas (e.g. outer regions of x-ray clusters) observed by XMM/RGS. We utilize the Photon Clean Method (PCM) to quantify these spectra (EBIT and XMM/RGS) in the form of ratios of Fe L lines in the emission complex near 1 keV. The variances of line fluxes are measured with bootstrap methods (Efron 1979). Both of these observations are further compared with theoretical predictions of Fe L line fluxes from APED and similar atomic databases.
Date: November 8, 2007
Creator: Carpenter, M; Beiersdorfer, P; Brown, G V; Chen, H C; Gu, M F & Jernigan, J G
Object Type: Report
System: The UNT Digital Library
REVIEW OF EXPERIMENTAL CAPABILITIES AND HYDRODYNAMIC DATA FOR VALIDATION OF CFD-BASED PREDICTIONS FOR SLURRY BUBBLE COLUMN REACTORS (open access)

REVIEW OF EXPERIMENTAL CAPABILITIES AND HYDRODYNAMIC DATA FOR VALIDATION OF CFD-BASED PREDICTIONS FOR SLURRY BUBBLE COLUMN REACTORS

The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.
Date: November 1, 2007
Creator: Guillen, Donna Post; Wendt, Daniel S.; Antal, Steven P. & Podowski, Michael Z.
Object Type: Article
System: The UNT Digital Library
Non-inclusive searches for squarks and gluinos at the Tevatron (open access)

Non-inclusive searches for squarks and gluinos at the Tevatron

Recent results from the CDF and D0 Collaborations on searches for squarks and gluinos at the Run II of the Fermilab Tevatron collider are presented. This review covers searches for final states involving specific mass hierarchies. The analyzed datasets correspond to an integrated luminosity of 300-1000 pb{sup -1} collected from proton anti-proton collisions at a center-of-mass energy of 1.96 TeV. No significant deviations from the Standard Model expectations are observed and limits on parameters of supersymmetry are set in generic MSSM and in specific mSUGRA scenarios.
Date: November 1, 2007
Creator: Biscarat, Catherine & /Lyon, IPN
Object Type: Article
System: The UNT Digital Library
Neutrino Experiments: Status, Recent Progress, and Prospects (open access)

Neutrino Experiments: Status, Recent Progress, and Prospects

None
Date: November 1, 2007
Creator: Brice, Steve
Object Type: Article
System: The UNT Digital Library
Novel photonic crystal cavities and related structures. (open access)

Novel photonic crystal cavities and related structures.

The key accomplishment of this project is to achieve a much more in-depth understanding of the thermal emission physics of metallic photonic crystal through theoretical modeling and experimental measurements. An improved transfer matrix technique was developed to enable incorporation of complex dielectric function. Together with microscopic theory describing emitter radiative and non-radiative relaxation dynamics, a non-equilibrium thermal emission model is developed. Finally, experimental methodology was developed to measure absolute emissivity of photonic crystal at high temperatures with accuracy of +/-2%. Accurate emissivity measurements allow us to validate the procedure to treat the effect of the photonic crystal substrate.
Date: November 1, 2007
Creator: Luk, Ting Shan
Object Type: Report
System: The UNT Digital Library
Measurement of Hydrogen Production Rate Based on Dew Point Temperatures: Independent Review (open access)

Measurement of Hydrogen Production Rate Based on Dew Point Temperatures: Independent Review

This independent review verified Idaho National Labotory's approach of measuring the rate of hydrogen production using dew point temperatures.
Date: November 1, 2007
Creator: Duffy, M.; Harrison, K. & Sheahen, T.
Object Type: Report
System: The UNT Digital Library
Generalization of the ERIT principle and method. (open access)

Generalization of the ERIT principle and method.

The paper describes the generalization of the method to produce secondary particles with a low-energy and low-intensity primary beam circulating in a Storage Ring with the Emittance-Recovery by Internal-Target (ERIT).
Date: November 4, 2007
Creator: Ruggiero, A. G.
Object Type: Article
System: The UNT Digital Library
Breakdown Characteristics Study on an 18 Cell X-band Structure (open access)

Breakdown Characteristics Study on an 18 Cell X-band Structure

A CLIC designed 18 cells, low group velocity (2.4% to 1.0% c), X-band (11.4 GHz) accelerator structure (denoted T18) was designed at CERN, its cells were built at KEK, and it was assembled and tested at SLAC. An interesting feature of this structure is that the gradient in the last cell is about 50% higher than that in the first cell. This structure has been RF conditioned at SLAC NLCTA for about 1400 hours where it incurred about 2200 breakdowns. This paper presents the characteristics of these breakdowns, including (1) the breakdown rate dependence on gradient, pulse width and conditioning time, (2) the breakdown distribution along the structure, (3) relation between breakdown and pulsed heating dependence study and (4) electric field decay time for breakdown changing over the whole conditioning time. Overall, this structure performed very well, having a final breakdown rate of less than 1e-6/pulse/m at 106 MV/m with 230 ns pulse width.
Date: November 12, 2008
Creator: Wang, Faya
Object Type: Article
System: The UNT Digital Library
Direct Measurements of an increased threshold for stimulated Brillouin scattering with polarization smoothing in ignition hohlraum plasmas (open access)

Direct Measurements of an increased threshold for stimulated Brillouin scattering with polarization smoothing in ignition hohlraum plasmas

We demonstrate a significant reduction of stimulated Brillouin scattering by polarization smoothing. The intensity threshold is measured to increase by a factor of 1.7 {+-} 0.2 when polarization smoothing is applied. The results were obtained in a high-temperature (T{sub 3} {approx_equal} 3 keV) hohlraum plasma where filamentation is negligible in determining the backscatter threshold. These results are explained by an analytical model relevant to ICF plasma conditions that modifies the linear gain exponent to account for polarization smoothing.
Date: November 8, 2007
Creator: Froula, D; Divol, L; Berger, R L; London, R; Meezan, N; Neumayer, P et al.
Object Type: Article
System: The UNT Digital Library
Red River Wildlife Management Area HEP Report, Habitat Evaluation Procedures, Technical Report 2004. (open access)

Red River Wildlife Management Area HEP Report, Habitat Evaluation Procedures, Technical Report 2004.

A habitat evaluation procedures (HEP) analysis conducted on the 314-acre Red River Wildlife Management Area (RRWMA) managed by the Idaho Department of Fish and Game resulted in 401.38 habitat units (HUs). Habitat variables from six habitat suitability index (HSI) models, comprised of mink (Mustela vison), mallard (Anas platyrhynchos), common snipe (Capella gallinago), black-capped chickadee (Parus altricapillus), yellow warbler (Dendroica petechia), and white-tailed deer (Odocoileus virginianus), were measured by Regional HEP Team (RHT) members in August 2004. Cover types included wet meadow, riverine, riparian shrub, conifer forest, conifer forest wetland, and urban. HSI model outputs indicate that the shrub component is lacking in riparian shrub and conifer forest cover types and that snag density should be increased in conifer stands. The quality of wet meadow habitat, comprised primarily of introduced grass species and sedges, could be improved through development of ephemeral open water ponds and increasing the amount of persistent wetland herbaceous vegetation e.g. cattails (Typha spp.) and bulrushes (Scirpus spp.).
Date: November 1, 2004
Creator: Ashley, Paul
Object Type: Report
System: The UNT Digital Library
An Incompressible Navier-Stokes with Particles Algorithm andParallel Implementation (open access)

An Incompressible Navier-Stokes with Particles Algorithm andParallel Implementation

We present a variation of an adaptive projection method forcomputing solutions to the incompressible Navier-Stokes equations withsuspended particles. To compute the divergence-free component of themomentum forcing due to the particle drag, we employ an approach whichexploits the locality and smoothness of the Laplacian of the projectionoperator applied to the discretized particle drag force. We presentconvergence and performance results to demonstrate the effectiveness ofthis approach.
Date: November 28, 2006
Creator: Martin, Daniel F.; Colella, Phillip & Keen, Noel D.
Object Type: Article
System: The UNT Digital Library
Photofragment Coincidence Imaging of Small I- (H2O)n Clusters Excited to the Charge-transfer-to-solvent State (open access)

Photofragment Coincidence Imaging of Small I- (H2O)n Clusters Excited to the Charge-transfer-to-solvent State

The photodissociation dynamics of small I{sup -}(H{sub 2}O){sub n} (n = 2-5) clusters excited to their charge-transfer-to-solvent (CTTS) states have been studied using photofragment coincidence imaging. Upon excitation to the CTTS state, two photodissociation channels were observed. The major channel ({approx}90%) is a 2-body process forming neutral I + (H{sub 2}O){sub n} photofragments, and the minor channel is a 3-body process forming I + (H{sub 2}O){sub n-1} + H{sub 2}O fragments. Both process display translational energy (P(E{sub T})) distributions peaking at E{sub T} = 0 with little available energy partitioned into translation. Clusters excited to the detachment continuum rather than to the CTTS state display the same two channels with similar P(E{sub T}) distributions. The observation of similar P(E{sub T}) distributions from the two sets of experiments suggests that in the CTTS experiments, I atom loss occurs after autodetachment of the excited (I(H{sub 2}O){sub n}{sup -})* cluster, or, less probably, that the presence of the excess electron has little effect on the departing I atom.
Date: November 9, 2005
Creator: Neumark, D. E. Szpunar, K. E. Kautzman, A. E. Faulhaber, and D. M.; Kautzman, K.E.; Faulhaber, A.E. & Faulhaber, A.E.
Object Type: Article
System: The UNT Digital Library
Radiation damage to BSCCO-2223 from 50 MEV protons. (open access)

Radiation damage to BSCCO-2223 from 50 MEV protons.

The use of HTS materials in high radiation environmentsrequires that the superconducting properties remain constant up to aradiation high dose. BSCCO-2223 samples from two manufacturers wereirradiated with 50 MeV protons at fluences of up to 5 x 1017 protons/cm2.The samples lost approximately 75 percent of their pre-irradiation Ic.This compares with Nb3Sn, which loses about 50 percent at the samedisplacements per atom.
Date: November 27, 2007
Creator: Zeller, A. F.; Ronningen, R. M.; Godeke, A.; Heilbronn, L. H.; McMahan-Norris, P. & Gupta, R.
Object Type: Article
System: The UNT Digital Library
The Extinction Toward the Galactic Bulge from RR Lyrae Stars (open access)

The Extinction Toward the Galactic Bulge from RR Lyrae Stars

The authors present mean reddenings toward 3525 RR0 Lyrae stars from the Galactic bulge fields of the MACHO Survey. These reddenings are determined using the color at minimum V-band light of the RR0 Lyrae stars themselves and are found to be in general agreement with extinction estimates at the same location obtained from other methods. Using 3256 stars located in the Galactic Bulge, they derive the selective extinction coefficient R{sub V,VR} = A{sub V}/E(V-R) = 4.2 {+-} 0.2. this value is what is expected for a standard extinction law with R{sub V,BV} = 3.1 {+-} 0.3
Date: November 7, 2007
Creator: Kunder, A.; Popowski, P.; Cook, K. & Chaboyer, B.
Object Type: Article
System: The UNT Digital Library
Current Conditions Risk Assessment for the 300-FF-5 Groundwater Operable Unit (open access)

Current Conditions Risk Assessment for the 300-FF-5 Groundwater Operable Unit

This report updates a baseline risk assessment for the 300 Area prepared in 1994. The update includes consideration of changes in contaminants of interest and in the environment that have occurred during the period of interim remedial action, i.e., 1996 to the present, as well as the sub-regions, for which no initial risk assessments have been conducted. In 1996, a record of decision (ROD) stipulated interim remedial action for groundwater affected by releases from 300 Area sources, as follows: (a) continued monitoring of groundwater that is contaminated above health-based levels to ensure that concentrations continue to decrease, and (b) institutional controls to ensure that groundwater use is restricted to prevent unacceptable exposure to groundwater contamination. In 2000, the groundwater beneath the two outlying sub-regions was added to the operable unit. In 2001, the first 5-year review of the ROD found that the interim remedy and remedial action objectives were still appropriate, although the review called for additional characterization activities. This report includes a current conditions baseline ecological and human health risk assessment using maximum concentrations in the environmental media of the 300-FF-5 Operable Unit and downstream conditions at the City of Richland, Washington. The scope for this assessment includes only …
Date: November 1, 2007
Creator: Miley, Terri B.; Bunn, Amoret L.; Napier, Bruce A.; Peterson, Robert E. & Becker, James M.
Object Type: Report
System: The UNT Digital Library