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Development of the Low Swirl Injector for Fuel-Flexible Gas Turbines (open access)

Development of the Low Swirl Injector for Fuel-Flexible Gas Turbines

Industrial gas turbines are primarily fueled with natural gas. However, changes in fuel cost and availability, and a desire to control carbon dioxide emissions, are creating pressure to utilize other fuels. There is an increased interest in the use of fuels from coal gasification, such as syngas and hydrogen, and renewable fuels, such as biogas and biodiesel. Current turbine fuel injectors have had years of development to optimize their performance with natural gas. The new fuels appearing on the horizon can have combustion properties that differ substantially from natural gas. Factors such as turbulent flame speed, heat content, autoignition characteristics, and range of flammability must be considered when evaluating injector performance. The low swirl injector utilizes a unique flame stabilization mechanism and is under development for gas turbine applications. Its design and mode of operation allow it to operate effectively over a wide range of conditions. Studies conducted at LBNL indicate that the LSI can operate on fuels with a wide range of flame speeds, including hydrogen. It can also utilize low heat content fuels, such as biogas and syngas. We will discuss the low swirl injector operating parameters, and how the LSC performs with various alternative fuels.
Date: February 14, 2007
Creator: Littlejohn, D.; Cheng, R.K.; Nazeer,W.A. & Smith, K.O
System: The UNT Digital Library
Structural Defects in Laterally Overgrown GaN Layers Grown onNon-polar Substrates (open access)

Structural Defects in Laterally Overgrown GaN Layers Grown onNon-polar Substrates

Transmission electron microscopy was used to study defects in lateral epitaxial layers of GaN which were overgrown on a template of a-plane (11{und 2}0) GaN grown on (1{und 1}02) r-plane Al2O3. A high density of basal stacking faults is formed in these layers because the c-planes of wurtzite structure are arranged along the growth direction. Density of these faults is decreasing at least by two orders of magnitude lower in the wings compared to the seed areas. Prismatic stacking faults and threading dislocations are also observed, but their densities drastically decrease in the wings. The wings grow with opposite polarities and the Ga-wing width is at least 6 times larger than N-wing and coalescence is rather difficult. Some tilt and twist was detected using Large Angle Convergent Beam Electron Diffraction.
Date: February 14, 2007
Creator: Liliental-Weber, Z.; Ni, X. & Morkoc, H.
System: The UNT Digital Library
2nd Annual DOE-ERSP PI Meeting: Abstracts (open access)

2nd Annual DOE-ERSP PI Meeting: Abstracts

Welcome to the annual 2007 Environmental Remediation Sciences Program (ERSP) Principal Investigators (PIs) meeting. The purpose of this meeting is to bring together all of the lead PIs and key Co-PIs in the program to share and review the results of funded research from the past year. This meeting allows program managers from the Environmental Remediation Sciences Division (ERSD) within the Office of Biological and Environmental Research (OBER) to gauge the progress and significance of the funded research, and it is also an important venue to showcase ERSP research to interested parties within DOE and other invited federal agency representatives. Additionally, these meetings should serve as an opportunity for funded PIs to view their research in the context of the entire ERSP portfolio. Past ERSP meetings have been very important venues for detailed discussion of research results among PIs, development of new research ideas, fostering new collaborations and discussion with ERSD program managers on future research efforts and/or initiatives within the program. In short, these meetings are an important resource for both program managers and PIs. There will be only one ERSP PI meeting for 2007. In years past, ERSD has sponsored two PI meetings, one in the spring and …
Date: March 14, 2007
Creator: Hazen, Terry C.
System: The UNT Digital Library
B0 to K0K0bar and Other Hadronic b to d Decays (open access)

B0 to K0K0bar and Other Hadronic b to d Decays

The b {yields} d penguin-dominated modes B {yields} K{bar K} have been observed at the B factories. in addition, the BABAR collaboration has reported the first time-dependent CP-violation measurement in B{sup 0} {yields} K{sup 0}{bar K}{sup 0}.
Date: March 14, 2007
Creator: Biesiada, J.
System: The UNT Digital Library
Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator (open access)

Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator

The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx} 52GV m{sup -1}. This effectively …
Date: March 14, 2007
Creator: Blumenfeld, Ian; Clayton, Christopher E.; Decker, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus et al.
System: The UNT Digital Library
First NNLL Prediction of B(\barB \rightarrow X_s \gamma) (open access)

First NNLL Prediction of B(\barB \rightarrow X_s \gamma)

The authors discuss the first NNLL prediction of the B {yields} X{sub s}{gamma} branching ratio, including important additional subtleties due to non-perturbative corrections and logarithmically-enhanced cut effects.
Date: March 14, 2007
Creator: Hurth, Tobias & /SLAC, /CERN
System: The UNT Digital Library
Flashing Slurry Releases (open access)

Flashing Slurry Releases

The Hanford K Basin Closure Project involves the retrieval, transfer and processing of radioactive contaminated slurries containing partially corroded spent nuclear fuel from the K Basin spent fuel pools. The spent fuel is primarily metallic fuel from the operation of the Hanford reactors. The Sludge Treatment Project is being designed to treat and package this material in preparation for ultimate disposal. The processing of the contaminated slurries includes further corrosion of the remaining uncorroded uranium metal in a large heated vessel to form a more stable metal oxide for packaging and storage.
Date: March 14, 2007
Creator: Schmitt, Bruce E. & Young, Jonathan
System: The UNT Digital Library
Measurement of the Time-dependent CP Asymmetry inB to D(*)_CP h0 Decays (open access)

Measurement of the Time-dependent CP Asymmetry inB to D(*)_CP h0 Decays

The authors report a measurement of the time-dependent CP-asymmetry parameters S and C in color-suppressed B{sup 0} {yields} D{sup (*)0}h{sup 0} decays, where h{sup 0} is a {pi}{sup 0}, {eta}, or {omega} meson, and the D{sup 0} decays to one of the CP eigenstates K{sup +}K{sup -}, K{sub S}{sup 0}{pi}{sup 0}, or K{sub S}{sup 0}{omega}. The data sample consists of 383 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B-factory at SLAC. The results are S = -0.56 {+-} 0.23 {+-} 0.05 and C = -0.23 {+-} 0.16 {+-} 0.04, where the first error is statistical and the second is systematic.
Date: March 14, 2007
Creator: Aubert, B.
System: The UNT Digital Library
Observation of CP Violation in B0 to K+pi- and B0 to pi+pi- (open access)

Observation of CP Violation in B0 to K+pi- and B0 to pi+pi-

The authors report observations of CP violation in the decays B{sup 0} {yields} K{sup +}{pi}{sup -} and B{sup 0} {yields} {pi}{sup +}{pi}{sup -} in a sample of 383 million {Upsilon}(4S) {yields} B{bar B} events. They find 4372 {+-} 82 B{sup 0} {yields} K{sup +}{pi}{sup -} decays and measure the direct Cp-violating charge asymmetry {Alpha}{sub K{pi}} = -0.107 {+-} 0.018(stat){sub -0.004}{sup +0.007}(syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample they find 1139 {+-} 49 B{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays and measure the CP-violating asymmetries S{sub {pi}{pi}} = -0.60 {+-} 0.11(stat) {+-} 0.03(syst) and C{sub {pi}{pi}} = -0.21 {+-} 0.09(stat) {+-} 0.02(syst). CP conservation in B{sup 0} {yields} {pi}{sup +}{pi}{sup -} (S{sub {pi}{pi}} = C{sub {pi}{pi}} = 0) is excluded at a confidence level 1-C.L. = 8 x 10{sup -8}, corresponding to 5.4 standard deviations.
Date: March 14, 2007
Creator: Aubert, B.
System: The UNT Digital Library
OPTIMIZATION OF WATER TO FUEL RATIOS IN CLADDED CYLINDER ARRAYS (open access)

OPTIMIZATION OF WATER TO FUEL RATIOS IN CLADDED CYLINDER ARRAYS

Often in criticality safety problems, the analyst is concerned about two conditions: Loss of Mass Control and Loss of Moderation Control. Determining and modeling the maximum amount of fuel that can fit in a given container is usually trivial. Determining and modeling the maximum amount of water (or other potential moderator) is usually more difficult. Optimization of the pitch has been shown to provide an increase in system reactivity. Both MOX and LEU systems have been shown to be sensitive to moderator intrusion in varying pitched configurations. The analysis will have to determine the effect of optimizing the pitch for each array.
Date: March 14, 2007
Creator: Huffer, J
System: The UNT Digital Library
Regulatory Background of VSS with respect to the USQ Process (open access)

Regulatory Background of VSS with respect to the USQ Process

None
Date: March 14, 2007
Creator: Brown, E & Mitchell, M
System: The UNT Digital Library
Spectroscopic Characterization and Simulation of Chemical Sputtering Using the DiMES Porous Plug Injector in DIII-D (open access)

Spectroscopic Characterization and Simulation of Chemical Sputtering Using the DiMES Porous Plug Injector in DIII-D

None
Date: March 14, 2007
Creator: McLean, A. G.; Davis, J. W.; Stangeby, P. C.; Brooks, N. H.; Whyte, D. G.; Allen, S. L. et al.
System: The UNT Digital Library
Spontaneous Superlattice Formation in Nanorods through PartialCation Exchange (open access)

Spontaneous Superlattice Formation in Nanorods through PartialCation Exchange

Lattice mismatch strains are widely known to controlnanoscale pattern formation in heteroepitaxy, but such effects have notbeen exploited in colloidal nanocrystal growth. We demonstrate acolloidal route to synthesizing CdS-Ag2S nanorod superlattices throughpartial cation exchange. Strain induces the spontaneous formation ofperiodic structures. Ab initio calculations of the interfacial energy andmodeling of strain energies show that these forces drive theself-organization. The nanorod superlattices exhibit high stabilityagainst ripening and phase mixing. These materials are tunablenear-infrared emitters with potential applications as nanometer-scaleoptoelectronic devices.
Date: March 14, 2007
Creator: Robinson, Richard D.; Sadtler, Bryce; Demchenko, Denis O.; Erdonmez, Can K.; Wang, Lin-Wang & Alivisatos, A. Paul
System: The UNT Digital Library
Symplectic Symmetry and the Ab Initio No-Core Shell Model (open access)

Symplectic Symmetry and the Ab Initio No-Core Shell Model

The symplectic symmetry of eigenstates for the 0{sub gs}{sup +} in {sup 16}O and the 0{sub gs}{sup +} and lowest 2{sup +} and 4{sup +} configurations of {sup 12}C that are well-converged within the framework of the no-core shell model with the JISP16 realistic interaction is examined. These states are found to project at the 85-90% level onto very few symplectic representations including the most deformed configuration, which confirms the importance of a symplectic no-core shell model and reaffirms the relevance of the Elliott SU(3) model upon which the symplectic scheme is built.
Date: March 14, 2007
Creator: Draayer, Jerry P.; Dytrych, Tomas; Sviratcheva, Kristina D.; Bahri, Chairul & Vary, James P.
System: The UNT Digital Library
ANALYSIS OF SPECIAL WASTE CONFIGURATIONS AT THE SRS WASTE MANAGEMENT FACILITIES (open access)

ANALYSIS OF SPECIAL WASTE CONFIGURATIONS AT THE SRS WASTE MANAGEMENT FACILITIES

Job Control Waste (JCW) at the Savannah River Site (SRS) Solid Waste Management Facilities (SWMF) may be disposed of in special containers, and the analysis of these containers requires developing specific analysis methodologies. A method has been developed for the routine assay of prohibited items (liquids, etc.) contained in a 30-gallon drum that is then placed into a 55-gallon drum. Method development consisted of system calibration with a NIST standard at various drum-to-detector distances, method verification with a liquid sample containing a known amount of Pu-238, and modeling the inner container using Ortec Isotopic software. Using this method for measurement of the known standard in the drum-in-drum configuration produced excellent agreement (within 15%) with the known value. Savannah River Site Solid Waste Management also requested analysis of waste contained in large black boxes (commonly 18-feet x 12-feet x 7-feet) stored at the SWMF. These boxes are frequently stored in high background areas and background radiation must be considered for each analysis. A detection limit of less than 150 fissile-gram-equivalents (FGE) of TRU waste is required for the black-box analyses. There is usually excellent agreement for the measurements at different distances and measurement uncertainties of about 50% are obtained at distances …
Date: May 14, 2007
Creator: Casella, V & Raymond Dewberry, R
System: The UNT Digital Library
CP Violation in B Decays (open access)

CP Violation in B Decays

None
Date: May 14, 2007
Creator: Biasini, M. & U., /Perugia
System: The UNT Digital Library
Effect of angular momentum on Valence-Quark Helicity Distributions (open access)

Effect of angular momentum on Valence-Quark Helicity Distributions

None
Date: May 14, 2007
Creator: Avakian, Harut; Brodsky, Stanley J.; Deur, Alexandre & Yuan, Feng
System: The UNT Digital Library
Evaluation of Multiplexed Foot-and-Mouth Disease Nonstructural Protein Antibody Assay Against Standardized Bovine Serum Panel (open access)

Evaluation of Multiplexed Foot-and-Mouth Disease Nonstructural Protein Antibody Assay Against Standardized Bovine Serum Panel

Liquid array technology has previously been used to show proof-of-principle of a multiplexed non structural protein serological assay to differentiate foot-and-mouth infected and vaccinated animals. The current multiplexed assay consists of synthetically produced peptide signatures 3A, 3B and 3D and recombinant protein signature 3ABC in combination with four controls. To determine diagnostic specificity of each signature in the multiplex, the assay was evaluated against a naive population (n = 104) and a vaccinated population (n = 94). Subsequently, the multiplexed assay was assessed using a panel of bovine sera generated by the World Reference Laboratory for foot-and-mouth disease in Pirbright, UK. This sera panel has been used to assess the performance of other singleplex ELISA-based non-structural protein antibody assays. The 3ABC signature in the multiplexed assay showed comparative performance to a commercially available non-structural protein 3ABC ELISA (Cedi test{reg_sign}) and additional information pertaining to the relative diagnostic sensitivity of each signature in the multiplex is acquired in one experiment. The encouraging results of the evaluation of the multiplexed assay against a panel of diagnostically relevant samples promotes further assay development and optimization to generate an assay for routine use in foot-and-mouth disease surveillance.
Date: May 14, 2007
Creator: Perkins, J; Parida, S & Clavijo, A
System: The UNT Digital Library
Exact seismic velocities for VTI and HTI media and extendedThomsen Formulas for stronger anisotropies (open access)

Exact seismic velocities for VTI and HTI media and extendedThomsen Formulas for stronger anisotropies

I explore a different type of approximation to the exactanisotropic wave velocities as a function of incidence angle invertically transversely isotropic (VTI) media. This method extends theThomsen weak anisotropy approach to stronger anisotropy withoutsignificantly affecting the simplicity of the formulas. One importantimprovement is that the peak of the quasi-SV-wave speed vsv(theta) islocated at the correct incidence angle theta= theta max, rather thanalways being at the position theta = 45o, which universally holds forThomsen's approximation although max theta = 45o is actually nevercorrect for any VTI anisotropic medium. The magnitudes of all the wavespeeds are also more closely approximated for all values of the incidenceangle. Furthermore, the value of theta max (which is needed in the newformulas) can be deduced from the same data that are typically used inthe weak anisotropy data analysis. The two examples presented are basedon systems having vertical fractures. The first set of model fractureshas their axes of symmetry randomly oriented in the horizontal plane.Such a system is then isotropic in the horizontal plane and, therefore,exhibits vertical transverse isotropic (VTI) symmetry. The second set offractures also has axes of symmetry in the horizontal plane, but it isassumed these axes are aligned so that the system exhibits horizontaltransverse …
Date: May 14, 2007
Creator: Berryman, J.G.
System: The UNT Digital Library
Gaining analytic control of parton showers (open access)

Gaining analytic control of parton showers

Parton showers are widely used to generate fully exclusive final states needed to compare theoretical models to experimental observations. While, in general, parton showers give a good description of the experimental data, the precise functional form of the probability distribution underlying the event generation is generally not known. The reason is that realistic parton showers are required to conserve four-momentum at each vertex. In this paper we investigate in detail how four-momentum conservation is enforced in a standard parton shower and why this destroysthe analytic control of the probability distribution. We show how to modify a parton shower algorithm such that it conserves four-momentum at each vertex, but for which the full analytic form of the probability distribution is known. We then comment how this analytic control can be used to match matrix element calculations with parton showers, and to estimate effects of power corrections and other uncertainties in parton showers.
Date: May 14, 2007
Creator: Tackmann, Frank; Bauer, Christian W. & Tackmann, Frank J.
System: The UNT Digital Library
Gaining analytical control of parton showers (open access)

Gaining analytical control of parton showers

None
Date: May 14, 2007
Creator: Bauer, Christian W. & Tackmann, Frank J.
System: The UNT Digital Library
Geometry of non-supersymmetric three-charge bound states (open access)

Geometry of non-supersymmetric three-charge bound states

We study the smooth non-supersymmetric three-charge microstatesof Jejjala, Madden, Ross and Titchener using Kaluza-Klein reductions of the solutions to five and four dimensions. Our aim is to improve our understanding of the relation between these non-supersymmetric solutions and the well-studied supersymmetric cases. We find some surprising qualitative differences. In the five-dimensional description, the solution has orbifold fixed points which break supersymmetry locally, so the geometries cannot be thought of as made up of separate half-BPS centers. In the four-dimensional description, the two singularities in the geometry are connected by a conical singularity, which makes it impossible to treat them independently and assign unambiguous brane charges to these centers.
Date: May 14, 2007
Creator: Gimon, Eric G.; Levi, Thomas S. & Ross, Simon F.
System: The UNT Digital Library
HADRON MULTIPLICITIES AT THE LHC . (open access)

HADRON MULTIPLICITIES AT THE LHC .

We present the predictions for hadron multiplicities in pp, pA and AA collisions at the LHC based on our approach to the Color Glass Condensate.
Date: May 14, 2007
Creator: Kharzeev, D.; Levin, E. & Nardi, M.
System: The UNT Digital Library
Hadron Spectroscopy at BaBar (open access)

Hadron Spectroscopy at BaBar

None
Date: May 14, 2007
Creator: Tosi, S. & /Genoa U. /INFN, Genoa
System: The UNT Digital Library