Two dimensional NMR and NMR relaxation studies of coal structure (open access)

Two dimensional NMR and NMR relaxation studies of coal structure

This report covers the progress made on the title project for the project period. Four major areas of inquiry are being pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups that determine the reactivity of coals. Special attention is being paid to methods that are compatible with the very high magic angle sample spinning rates needed for operation at the high magnetic field strengths available today. Polarization inversion methods utilizing the difference in heat capacities of small groups of spins are particularly promising. Methods combining proton-proton spin diffusion with {sup 13}C CPMAS readout are being developed to determine the connectivity of functional groups in coals in a high sensitivity relay type of experiment. Additional work is aimed a delineating the role of methyl group rotation in the proton NMR relaxation behavior of coals.
Date: May 27, 1992
Creator: Zilm, K.W.
Object Type: Report
System: The UNT Digital Library
Model for H/sup -/ and D/sup -/ production by hydrogen backscattering (open access)

Model for H/sup -/ and D/sup -/ production by hydrogen backscattering

The Marlowe Monte-Carlo backscattering code has been used to calculate particle reflection coefficients and energy distributions for H, D incident upon Li, K, Ni, Cu, Mo, Ag, Cs, Hf, W, Pt, and U surfaces. The backscattered energy and angular distributions are combined with a model for formation and survival probabilities for H/sup -/, D/sup -/ leaving the surface. A least-squares fit of experimental measurements of H/sup -/ yields from the composite surface, Cs/Cu, has been used to obtain two semi-empirical constants, ..cap alpha.., ..beta.. which enter into the formation and survival probabilities. These probabilities are used to calculate the production probability which in turn provides an upper limit to the negative ion yield. The choice of electrode material is discussed as a function of atomic number.
Date: May 27, 1980
Creator: Hiskes, J.R. & Schneider, P.J.
Object Type: Report
System: The UNT Digital Library
Seismic review of the R. E. Ginna Nuclear Power Plant as part of the Systematic Evaluation Program for the Nuclear Regulatory Commission (open access)

Seismic review of the R. E. Ginna Nuclear Power Plant as part of the Systematic Evaluation Program for the Nuclear Regulatory Commission

This paper is a progress report on work at the Lawrence Livermore National Laboratory (LLNL) to perform a limited seismic reassessment of the Robert E. Ginna Nuclear Power Plant. The reassessment is being done for the Nuclear Regulatory Commission (NRC) as part of the Systematic Evaluation Program. The reassessment focuses generally on the reactor coolant pressure boundary and on those systems and components necessary to shut down the reactor safely and to maintain it in a safe shutdown condition following a postulated earthquake characterized by a peak horizontal ground acceleration of 0.2 g. Methods and modeling procedures used to analyze a complex of interconnected buildings are highlighted.
Date: May 27, 1980
Creator: Murray, R. C.; Nelson, T. A.; Ng, D. S.; Liaw, C. Y.; Levin, H. A. & Cheng, T. M.
Object Type: Article
System: The UNT Digital Library
Longitudinal compression of heavy-ion beams with minimum requirements on final focus (open access)

Longitudinal compression of heavy-ion beams with minimum requirements on final focus

A method is developed to compress a heavy-ion beam longitudinally in such a way that the compressed pulse has a constant line-charge density profile and uniform longitudinal momentum. These conditions may be important from the standpoint of final focusing. By realizing the similarity of the equations that describe the 1-D charged-particle motion to the equations that describe 1-D ideal gas flow, the evolution of lambda and the velocity tilt can be calculated using the method of characteristics developed for unsteady supersonic gasdynamics. Particle simulations confirm the theory. Various schemes for pulse shaping have been investigated.
Date: May 27, 1986
Creator: Ho, D.D.M.; Bangerter, R.O.; Mark, J.W.K.; Brandon, S.T. & Lee, E.P.
Object Type: Article
System: The UNT Digital Library
Reliability Results of NERSC Systems (open access)

Reliability Results of NERSC Systems

In order to address the needs of future scientific applications for storing and accessing large amounts of data in an efficient way, one needs to understand the limitations of current technologies and how they may cause systeminstability or unavailability. A number of factors can impact system availability ranging from facility-wide power outage to a single point of failure such as network switches or global file systems. In addition, individual component failure in a system can degrade the performance of that system. This paper focuses on analyzing both of these factors and their impacts on the computational and storage systems at NERSC. Component failure data presented in this report primarily focuses on disk drive in on of the computational system and tape drive failure in HPSS. NERSC collected available component failure data and system-wide outages for its computational and storage systems over a six-year period and made them available to the HPC community through the Petascale Data Storage Institute.
Date: May 27, 2008
Creator: Petascale Data Storage Institute
Object Type: Report
System: The UNT Digital Library
BIOTIGER, A NATURAL MICROBIAL PRODUCT FOR ENHANCED HYDROCARBON RECOVERY FROM OIL SANDS. (open access)

BIOTIGER, A NATURAL MICROBIAL PRODUCT FOR ENHANCED HYDROCARBON RECOVERY FROM OIL SANDS.

BioTiger{trademark} is a unique microbial consortia that resulted from over 8 years of extensive microbiology screening and characterization of samples collected from a century-old Polish waste lagoon. BioTiger{trademark} shows rapid and complete degradation of aliphatic and aromatic hydrocarbons, produces novel surfactants, is tolerant of both chemical and metal toxicity and shows good activity at temperature and pH extremes. Although originally developed and used by the U.S. Department of Energy for bioremediation of oil-contaminated soils, recent efforts have proven that BioTiger{trademark} can also be used to increase hydrocarbon recovery from oil sands. This enhanced ex situ oil recovery process utilizes BioTiger{trademark} to optimize bitumen separation. A floatation test protocol with oil sands from Ft. McMurray, Canada was used for the BioTiger{trademark} evaluation. A comparison of hot water extraction/floatation test of the oil sands performed with BioTiger{trademark} demonstrated a 50% improvement in separation as measured by gravimetric analysis in 4 h and a five-fold increase at 25 hr. Since BioTiger{trademark} performs well at high temperatures and process engineering can enhance and sustain metabolic activity, it can be applied to enhance recovery of hydrocarbons from oil sands or other complex recalcitrant matrices.
Date: May 27, 2008
Creator: Brigmon, R; Topher Berry, T; Whitney Jones, W & Charles Milliken, C
Object Type: Article
System: The UNT Digital Library
DEMONSTRATION OF EQUIVALENCY OF CANE AND SOFTWOOD BASED CELOTEX FOR MODEL 9975 SHIPPING PACKAGES (open access)

DEMONSTRATION OF EQUIVALENCY OF CANE AND SOFTWOOD BASED CELOTEX FOR MODEL 9975 SHIPPING PACKAGES

Cane-based Celotex{trademark} has been used extensively in various Department of Energy (DOE) packages as a thermal insulator and impact absorber. Cane-based Celotex{trademark} fiberboard was only manufactured by Knight-Celotex Fiberboard at their Marrero Plant in Louisiana. However, Knight-Celotex Fiberboard shut down their Marrero Plant in early 2007 due to impacts from hurricane Katrina and other economic factors. Therefore, cane-based Celotex{trademark} fiberboard is no longer available for use in the manufacture of new shipping packages requiring the material as a component. Current consolidation plans for the DOE Complex require the procurement of several thousand new Model 9975 shipping packages requiring cane-based Celotex{trademark} fiberboard. Therefore, an alternative to cane-based Celotex{trademark} fiberboard is needed. Knight-Celotex currently manufactures Celotex{trademark} fiberboard from other cellulosic materials, such as hardwood and softwood. A review of the relevant literature has shown that softwood-based Celotex{trademark} meets all parameters important to the Model 9975 shipping package.
Date: May 27, 2008
Creator: Watkins, R & Jason Varble, J
Object Type: Article
System: The UNT Digital Library
User's Guide for TOUGH2-MP - A Massively Parallel Version of the TOUGH2 Code (open access)

User's Guide for TOUGH2-MP - A Massively Parallel Version of the TOUGH2 Code

TOUGH2-MP is a massively parallel (MP) version of the TOUGH2 code, designed for computationally efficient parallel simulation of isothermal and nonisothermal flows of multicomponent, multiphase fluids in one, two, and three-dimensional porous and fractured media. In recent years, computational requirements have become increasingly intensive in large or highly nonlinear problems for applications in areas such as radioactive waste disposal, CO2 geological sequestration, environmental assessment and remediation, reservoir engineering, and groundwater hydrology. The primary objective of developing the parallel-simulation capability is to significantly improve the computational performance of the TOUGH2 family of codes. The particular goal for the parallel simulator is to achieve orders-of-magnitude improvement in computational time for models with ever-increasing complexity. TOUGH2-MP is designed to perform parallel simulation on multi-CPU computational platforms. An earlier version of TOUGH2-MP (V1.0) was based on the TOUGH2 Version 1.4 with EOS3, EOS9, and T2R3D modules, a software previously qualified for applications in the Yucca Mountain project, and was designed for execution on CRAY T3E and IBM SP supercomputers. The current version of TOUGH2-MP (V2.0) includes all fluid property modules of the standard version TOUGH2 V2.0. It provides computationally efficient capabilities using supercomputers, Linux clusters, or multi-core PCs, and also offers many user-friendly features. …
Date: May 27, 2008
Creator: Zhang, Keni; Zhang, Keni; Wu, Yu-Shu & Pruess, Karsten
Object Type: Report
System: The UNT Digital Library
Turbulence-Flame Interactions in Type Ia Supernovae (open access)

Turbulence-Flame Interactions in Type Ia Supernovae

The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, 1 to 8 x 107 g cm-3, spans the transition from the laminar flamelet regime to the distributed burning regime where small scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SN Ia, we find a transition density between 1 and 3 x 107 g cm-3 where the nature of the burning changes ualitatively. By 1 x 107 g cm-3, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis Number approaches unity. That is, the flame resembles …
Date: May 27, 2008
Creator: Aspden, Andrew J.; Bell, John B.; Day, Marc S.; Woosley, Stan E. & Zingale, Mike
Object Type: Article
System: The UNT Digital Library
INITIAL SLUDGE BATCH 4 TANK 40 DECANT VARIABILITY STUDY WITH FRIT 510 (open access)

INITIAL SLUDGE BATCH 4 TANK 40 DECANT VARIABILITY STUDY WITH FRIT 510

Sludge Batch 4 (SB4) is currently being processed in the Defense Waste Processing Facility (DWPF) using Frit 510. The slurry pumps in Tank 40 are experiencing in-leakage of bearing water, which is causing the sludge slurry feed in Tank 40 to become dilute at a rapid rate. Currently, the DWPF is removing this dilution water by performing caustic boiling during the Sludge Receipt and Adjustment Tank (SRAT) cycle. In order to alleviate prolonged SRAT cycle times that may eventually impact canister production rates, decant scenarios of 100, 150, and 200 kilogallons of supernate were proposed for Tank 40 during the DWPF March outage. Based on the results of the preliminary assessment issued by the Savannah River National Laboratory (SRNL), the Liquid Waste Organization (LWO) issued a Technical Task Request (TTR) for SRNL to (1) perform a more detailed evaluation using updated SB4 compositional information and (2) assess the viability of Frit 510 and determine any potential impacts on the SB4 system. As defined in the TTR, LWO requested that SRNL validate the sludge--only SB4 flowsheet and the coupled operations flowsheet using the 100K gallon decant volume as well as the addition of 3 wt% sodium on a calcined oxide basis. …
Date: May 27, 2008
Creator: Raszewski, F; Tommy Edwards, T; David Peeler, D; David Best, D; Irene Reamer, I & Phyllis Workman, P
Object Type: Report
System: The UNT Digital Library
Hydrogen Commercialization: Transportation Fuel for the 21st Century (open access)

Hydrogen Commercialization: Transportation Fuel for the 21st Century

Since 1999, SunLine Transit Agency has worked with the U.S. Department of Energy (DOE), U.S. Department of Defense (DOD), and the U.S. Department of Transportation (DOT) to develop and test hydrogen infrastructure, fuel cell buses, a heavy-duty fuel cell truck, a fuel cell neighborhood electric vehicle, fuel cell golf carts and internal combustion engine buses operating on a mixture of hydrogen and compressed natural gas (CNG). SunLine has cultivated a rich history of testing and demonstrating equipment for leading industry manufacturers in a pre-commercial environment. Visitors to SunLine's "Clean Fuels Mall" from around the world have included government delegations and agencies, international journalists and media, industry leaders and experts and environmental and educational groups.
Date: May 27, 2008
Creator: Toro, Apolonio Del
Object Type: Report
System: The UNT Digital Library
Quantum Coherence Arguments for Cosmological Scale (open access)

Quantum Coherence Arguments for Cosmological Scale

Homogeneity and correlations in the observed CMB are indicative of some form of cosmological coherence in early times. Quantum coherence in the early universe would be expected to give space-like phase coherence to any effects sourced to those times. If dark energy de-coherence is assumed to occur when the rate of expansion of the relevant cosmological scale parameter in the Friedmann-Lemaitre equations is no longer supra-luminal, a critical energy density is immediately defined. It is shown that the general class of dynamical models so defined necessarily requires a spatially flat cosmology in order to be consistent with observed structure formation. The basic assumption is that the dark energy density which is fixed during de-coherence is to be identified with the cosmological constant. It is shown for the entire class of models that the expected amplitude of fluctuations driven by the dark energy de-coherence process is of the order needed to evolve into the fluctuations observed in cosmic microwave background radiation and galactic clustering. The densities involved during de-coherence which correspond to the measured dark energy density turn out to be of the electroweak symmetry restoration scale. In an inflationary cosmology, this choice of the scale parameter in the FL equations …
Date: May 27, 2005
Creator: Lindesay, James
Object Type: Report
System: The UNT Digital Library
Preparation and Reactions of Base-FreeBis(1,2,4-tri-tert-butylcyclopentadienyl)uranium Methylimide, Cp'2U=NMe,and Related Compounds (open access)

Preparation and Reactions of Base-FreeBis(1,2,4-tri-tert-butylcyclopentadienyl)uranium Methylimide, Cp'2U=NMe,and Related Compounds

The uranium metallocenes, [eta5-1,3-(Me3E)2C5H3]2UMe2 (E =C, Si), react with NH3 to give the dimers{[eta5-1,3-(Me3E)2C5H3]2U}2(mu-NH)2 (E = C (1), Si (2)) but withp-toluidine to give the monomeric diamides,[eta5-1,3-(Me3E)2C5H3]2U(NH-p-tolyl)2 (E = C (3), Si (4)). The diamides[eta5-1,3-(Me3E)2C5H3]2U(NH-p-tolyl)2 (E = C (3), Si (4)) do noteliminate p- toluidine but sublime intact at 140oC in vacuum. The uraniummetallocene, [eta5-1,2,4-(Me3C)3C5H2]2UMe2, reacts with RNH2 to yield[eta5-1,2,4-(Me3C)3C5H2]2U(NHR)2 (R = Me (8), PhCH2 (9), p-tolyl (10)),which are isolated as crystalline solids. In benzene solution thesediamides are in equilibrium with [eta5-1,2,4-(Me3C)3C5H2]2U=NR, which maybe isolated pure when R is Me (11) or p-tolyl (12), and the primaryamine. The monomeric imide, [eta5-1,2,4-(Me3C)3C5H2]2U=NMe (11), reactswith R'=CR' to yield the cycloaddition products[eta5-1,2,4-(Me3C)3C5H2]2U[N(Me)C(R')=C(R')](R' = Me (15), Ph (16)),which react with excess MeNH2 to regenerate the diamide[eta5-1,2,4-(Me3C)3C5H2]2U(NHMe)2 (8) and MeN=C(R')CH(R'). Themethylimide, [eta5-1,2,4-(Me3C)3C5H2]2U=NMe (11), does not react withMe3SiX reagents; a model is proposed that rationalizes this reactivitypattern.
Date: May 27, 2005
Creator: Zi, Guofu; Blosch, Laura L.; Jia, Li & Andersen, Richard A.
Object Type: Article
System: The UNT Digital Library
Coordination of Retail Demand Response with Midwest ISO Markets (open access)

Coordination of Retail Demand Response with Midwest ISO Markets

The Organization of Midwest ISO States (OMS) launched the Midwest Demand Resource Initiative (MWDRI) in 2007 to identify barriers to deploying demand response (DR) resources in the Midwest Independent System Operator (MISO) region and develop policies to overcome them. The MWDRI stakeholders decided that a useful initial activity would be to develop more detailed information on existing retail DR programs and dynamic pricing tariffs, program rules, and utility operating practices. This additional detail could then be used to assess any"seams issues" affecting coordination and integration of retail DR resources with MISO's wholesale markets. Working with state regulatory agencies, we conducted a detailed survey of existing DR programs, dynamic pricing tariffs, and their features in MISO states. Utilities were asked to provide information on advance notice requirements to customers, operational triggers used to call events (e.g. system emergencies, market conditions, local emergencies), use of these DR resources to meet planning reserves requirements, DR resource availability (e.g., seasonal, annual), participant incentive structures, and monitoring and verification (M&V) protocols. This report describes the results of this comprehensive survey and discusses policy implications for integrating legacy retail DR programs and dynamic pricing tariffs into organized wholesale markets. Survey responses from 37 MISO members and …
Date: May 27, 2008
Creator: Bharvirkar, Ranjit; Bharvirkar, Ranjit; Goldman, Charles; Heffner, Grayson & Sedano, Richard
Object Type: Article
System: The UNT Digital Library
Quantitative models of subduction zone fluids: How hydrous phases in the slab determine the composition of subduction zone lavas (open access)

Quantitative models of subduction zone fluids: How hydrous phases in the slab determine the composition of subduction zone lavas

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Date: May 27, 2004
Creator: Feineman, M; Ryerson, F J & DePaolo, D
Object Type: Article
System: The UNT Digital Library
Enzymatic Ligation Creates Discrete Multi-Nanoparticle Building Blocks for Self-Assembly (open access)

Enzymatic Ligation Creates Discrete Multi-Nanoparticle Building Blocks for Self-Assembly

Enzymatic ligation of discrete nanoparticle?DNA conjugates creates nanoparticle dimer and trimer structures in which the nanoparticles are linked by single-stranded DNA, rather than double-stranded DNA as in previous experiments. Ligation is verified by agarose gel and small-angle X-ray scattering. This capability is utilized in two ways: first to create a new class of multiparticle building blocks for nanoscale self-assembly; second to develop a system which can amplify a population of discrete nanoparticle assemblies.
Date: May 27, 2008
Creator: Claridge, Shelley A.; Mastroianni, Alexander J.; Au, Yeung B.; Liang, Huiyang W.; Micheel, Christine M.; Frechet, Jean M.J. et al.
Object Type: Article
System: The UNT Digital Library
The mechanism for iron-catalyzed alkene isomerization in solution (open access)

The mechanism for iron-catalyzed alkene isomerization in solution

Here we report nano- through microsecond time-resolved IR experiments of iron-catalyzed alkene isomerization in room-temperature solution. We have monitored the photochemistry of a model system, Fe(CO){sub 4}({eta}{sup 2}-1-hexene), in neat 1-hexene solution. UV-photolysis of the starting material leads to the dissociation of a single CO to form Fe(CO){sub 3}({eta}{sup 2}-1-hexene), in a singlet spin state. This CO loss complex shows a dramatic selectivity to form an allyl hydride, HFe(CO){sub 3}({eta}{sup 3}-C{sub 6}H{sub 11}), via an internal C-H bond-cleavage reaction in 5-25 ns. We find no evidence for the coordination of an alkene molecule from the bath to the CO loss complex, but do observe coordination to the allyl hydride, indicating that it is the key intermediate in the isomerization mechanism. Coordination of the alkene ligand to the allyl hydride leads to the formation of the bis-alkene isomers, Fe(CO){sub 3}({eta}{sup 2}-1-hexene)({eta}{sup 2}-2-hexene) and Fe(CO){sub 3}({eta}{sup 2}-1-hexene){sub 2}. Because of the thermodynamic stability of Fe(CO){sub 3}({eta}{sup 2}-1-hexene)({eta}{sup 2}-2-hexene) over Fe(CO){sub 3}({eta}{sup 2}-1-hexene){sub 2} (ca. 12 kcal/mol), nearly 100% of the alkene population will be 2-alkene. The results presented herein provide the first direct evidence for this mechanism in solution and suggest modifications to the currently accepted mechanism.
Date: May 27, 2008
Creator: Sawyer, Karma R.; Glascoe, Elizabeth A.; Cahoon, James F.; Schlegel, Jacob P. & Harris, Charles B.
Object Type: Article
System: The UNT Digital Library
Damping beam displacements through phase mixing: an illustrative model (open access)

Damping beam displacements through phase mixing: an illustrative model

We develop a simple model of a beam transported in a hard wall channel (an idealized very-high-order magnetic-multipole channel). The extremely anharmonic nature of the potential leads to damping of coherent transverse displacements of the beam via phase mixing. For the case of small uniform displacements of the beam we can write down by inspection the analytical form of the motion of the beam centroid. The same technique allows us to evaluate the effects of focussing and scattering elements in the transport channel upon the damping of the transverse motion of the beam.
Date: May 27, 1983
Creator: Barletta, W. A. & Briggs, R. J.
Object Type: Article
System: The UNT Digital Library
Twos in two photon physics: A convention for the. gamma. gamma. * width of a spin-one particle (open access)

Twos in two photon physics: A convention for the. gamma. gamma. * width of a spin-one particle

The two conventions for the {gamma}{gamma}* width of a spin-one resonance are discussed. It is shown that the more reasonable one is the one that gives the larger experimental value. 5 refs.
Date: May 27, 1988
Creator: Cahn, R.N.
Object Type: Article
System: The UNT Digital Library
Improved 50-kV pulser design (open access)

Improved 50-kV pulser design

A compact 50 kilovolt pulser has been developed as a gas switch trigger. This unit combines a grounded grid thyratron with a ferrite loaded step-up transformer to provide the required output voltage. A magnetic switch at the output brings the risetime down to the ten nanosecond range. Unit operation is specified into a 25 ohm resistive load. Integral with the pulser package is the necessary low level support electronics to power the thyratron and to provide trigger and diagnostic functions. Package volume is less than .02 m/sup 3/.
Date: May 27, 1982
Creator: Oicles, J.A. & Fulkerson, E.S.
Object Type: Article
System: The UNT Digital Library
ECRH in tandem mirror machines (open access)

ECRH in tandem mirror machines

The thermal barrier concept and the use of ECRH to generate the several electron populations required to establish confinement are discussed. Important physics issues related to the microwave heating are discussed. Fokker-Planck calculations which model the heating processes are presented, followed by recent experimental data on hot electron heating.
Date: May 27, 1983
Creator: Stallard, B.W.
Object Type: Article
System: The UNT Digital Library
Development of advanced NO sub x control concepts for coal-fired utility boilers (open access)

Development of advanced NO sub x control concepts for coal-fired utility boilers

CombiNO{sub x} is an integration of three technologies: modified reburning, promoted selective noncatalytic reduction (SNCR) and methanol injection. These technologies are combined to achieve high levels of NO{sub x}, emission reduction from coal fired power plants equipped with SO{sub 2} scrubbers. The first two steps, modified reburning and promoted SNCR are linked. It has been shown that, performance of the SNCR agent is dependent upon local oxidation of CO. Reburning is used to generate the optimum amount of CO to promote the SNCR agent, although lower levels of reburning are needed than are traditionally applied in the reburning process. If the reburn fuel is natural gas, the combination of reburning and SNCR may result in a significant cost savings over conventional reburning. The third step, injection of methanol into the flue gas, is used to convert NO to NO{sub 2} which may subsequently be removed in a wet scrubber.
Date: May 27, 1992
Creator: Evans, A.; Newhall, J.; England, G. & Seeker, W. R.
Object Type: Report
System: The UNT Digital Library
Characterization of muntjac DNA (open access)

Characterization of muntjac DNA

Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange.
Date: May 27, 1981
Creator: Davis, R.C.
Object Type: Report
System: The UNT Digital Library
Symmetry issues in a class of ion beam targets using short direct drive pulses (open access)

Symmetry issues in a class of ion beam targets using short direct drive pulses

We address a class of modified ion beam targets where the symmetry issues are ameliorated in the regime of short bursts of direct drive pulses. Short pulses are here defined so that the fractional change in target radii of peak beam energy deposition are assumed to be small (during each such direct drive burst with a fixed beam focal radius). This requirement is actually not stringent on the temporal pulse-length. In fact we show an explicit example where this can be satisfied by a greater than or equal to 60 ns direct drive pulse-train. A new beam placement scheme is used which systematically eliminated low order spherical harmonic asymmetries. The residual asymmetries of such pulses are studied with both simple model and numerical simulations.
Date: May 27, 1986
Creator: Mark, J.W.K. & Lindl, J.D.
Object Type: Article
System: The UNT Digital Library