Alkaloid-derived molecules in low rank Argonne premium coals. (open access)

Alkaloid-derived molecules in low rank Argonne premium coals.

Molecules that are probably derived from alkaloids have been found in the extracts of the subbituminous and lignite Argonne Premium Coals. High resolution mass spectrometry (HRMS) and liquid chromatography mass spectrometry (LCMS) have been used to characterize pyridine and supercritical extracts. The supercritical extraction used an approach that has been successful for extracting alkaloids from natural products. The first indication that there might be these natural products in coals was the large number of molecules found containing multiple nitrogen and oxygen heteroatoms. These molecules are much less abundant in bituminous coals and absent in the higher rank coals.
Date: November 30, 2000
Creator: Winans, R. E.; Tomczyk, N. A. & Hunt, J. E.
System: The UNT Digital Library
A distributed application server for automatic differentiation. (open access)

A distributed application server for automatic differentiation.

The ADIC Application Server brings the accuracy and efficiency of automatic differentiation to the World Wide Web. Users of the ADIC Application Server can upload source code written in ANSI-C, manage remote files, differentiate selected functions, and download code augmented with derivative computations. Using a simple driver and linking to the appropriate libraries, the user can compile and run the differentiated code locally. We discuss the unique requirements for an automatic differentiation application server and describe the implementation of the ADIC Application Server.
Date: November 30, 2000
Creator: Norris, B. & Hovland, P. D.
System: The UNT Digital Library
The experiment road to the heavier quarks and other heavy objects (open access)

The experiment road to the heavier quarks and other heavy objects

None
Date: November 30, 2000
Creator: Appel, Jeffrey A.
System: The UNT Digital Library
Fast track triggering for the CDF II Detector (open access)

Fast track triggering for the CDF II Detector

None
Date: November 30, 2000
Creator: Bloom, Kenneth
System: The UNT Digital Library
A Galerkin Implementation of the Generalized Helmholtz Decomposition for Vorticy Formulations (open access)

A Galerkin Implementation of the Generalized Helmholtz Decomposition for Vorticy Formulations

None
Date: November 30, 2000
Creator: INGBER,MARC STUART & KEMPKA,STEVEN N.
System: The UNT Digital Library
GAMMASPHERE+FMA : a journey beyond the proton drip-line. (open access)

GAMMASPHERE+FMA : a journey beyond the proton drip-line.

The majority of experiments performed during the 2-year long stay of GAMMAS-PHERE at the Argonne National Laboratory aimed to study proton-rich nuclei far from the line of stability at and beyond the proton drip-line. A high reaction channel selectivity was required to assign in-beam {gamma}-ray transitions to weakly populated exotic nuclei in the presence of background from strong reaction channels. In many of the experiments this was achieved by using the Argonne fragment mass analyzer to separate heavy-ion fusion-evaporation reaction products from scattered beam and disperse them according to their mass-over-charge-state ratio. For medium mass and heavy a and proton emitters the Recoil-Decay Tagging method was implemented. In-beam {gamma}-ray transitions were observed in several proton emitters between Z=50 and Z=82. Among others, rotational bands were assigned to {sup 141}Ho and {sup 131}Eu. A quadruple deformation of {beta}=0.25(4) was deduced for the ground state in {sup 141}Ho from the extracted dynamic moment of inertia. Based on observed band crossings and signature splittings the 7/2{sup {minus}} [523] and 1/2{sup +}[411] configurations were proposed for the ground state and the isomeric state, respectively. Comparison with particle-rotor calculations indicates, however, that {sup 141}Ho may have significant hexadecapole deformation and could be triaxial.
Date: November 30, 2000
Creator: Seweryniak, D.; Woods, P. J.; Ressler, J. J.; Davids, C. N.; Heinz, A.; Sonzogni, A. A. et al.
System: The UNT Digital Library
Geometric Reasoning in Generative Process Planning (open access)

Geometric Reasoning in Generative Process Planning

None
Date: November 30, 2000
Creator: Calton, T.L.
System: The UNT Digital Library
A grid-enabled MPI : message passing in heterogeneous distributed computing systems. (open access)

A grid-enabled MPI : message passing in heterogeneous distributed computing systems.

Application development for high-performance distributed computing systems, or computational grids as they are sometimes called, requires grid-enabled tools that hide mundate aspects of the heterogeneous grid environment without compromising performance. As part of an investigation of these issues, they have developed MPICH-G, a grid-enabled implementation of the Message Passing Interface (MPI) that allows a user to run MPI programs across multiple computers at different sites using the same commands that would be used on a parallel computer. This library extends the Argonne MPICH implementation of MPI to use services provided by the globus grid toolkit. In this paper, they describe the MPICH-G implementation and present preliminary performance results.
Date: November 30, 2000
Creator: Foster, I. & Karonis, N. T.
System: The UNT Digital Library
Improbability of Nuclear Criticality When Disposing of Transuranic Waste at the Waste Isolation Pilot Plant (open access)

Improbability of Nuclear Criticality When Disposing of Transuranic Waste at the Waste Isolation Pilot Plant

None
Date: November 30, 2000
Creator: Rechard, R.P.
System: The UNT Digital Library
The Observation of an Optimal Wire Number Range in Long Implosion Time Aluminum Z-Pinches (open access)

The Observation of an Optimal Wire Number Range in Long Implosion Time Aluminum Z-Pinches

None
Date: November 30, 2000
Creator: Coverdale, Christine A.; Deeney, Christopher; Douglas, Melissa R.; Apruzese, J. P.; Whitney, K. G.; Thornhill, J. W. et al.
System: The UNT Digital Library
Saturated Plasma X-Ray Laser at 19 nm (open access)

Saturated Plasma X-Ray Laser at 19 nm

Saturated operation of a tabletop laser plasma X-ray laser at 19 nm is demonstrated with output energy of 2.5 {micro}J. The narrow beam divergence, high repetition rate, wavelength scalability, short pulse duration, high monochromaticity and high brightness make it a potential tool for X-ray laser applications, including seeding a future X-ray free electron laser.
Date: November 30, 2000
Creator: Li, Y.; Dunn, J.; Nilsen, J.; Osterheld, A.; Barbee, T. W., Jr. & Shlyaptsev, V. N.
System: The UNT Digital Library
Search for single top production with CDF (open access)

Search for single top production with CDF

None
Date: November 30, 2000
Creator: al., Pierre Savard et
System: The UNT Digital Library
An update on the Tevatron collimator system for Collider Run II (open access)

An update on the Tevatron collimator system for Collider Run II

None
Date: November 30, 2000
Creator: Church, Michael D.
System: The UNT Digital Library
Analytic Models of High-Temperature Hohlraums (open access)

Analytic Models of High-Temperature Hohlraums

A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P{sub s} = [A{sub s}+(1{minus}{alpha}{sub W})A{sub W}+A{sub H}]{sigma}T{sub R}{sup 4} + (4V{sigma}/c)(dT{sub R}{sup r}/dt) where P{sub S} is the total power radiated by the source, A{sub s} is the source area, A{sub W} is the area of the cavity wall excluding the source and holes in the wall, A{sub H} is the area of the holes, {sigma} is the Stefan-Boltzmann constant, T{sub R} is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo {alpha}{sub W} {triple_bond} (T{sub W}/T{sub R}){sup 4} where T{sub W} is the brightness temperature of area A{sub W}. The net power radiated by the source P{sub N} = P{sub S}-A{sub S}{sigma}T{sub R}{sup 4}, which suggests that for laser-driven hohlraums the conversion efficiency {eta}{sub CE} be defined as P{sub N}/P{sub LASER}. The characteristic time required to change T{sub R}{sup 4} in response to a change in P{sub N} is 4V/C[(l{minus}{alpha}{sub W})A{sub W}+A{sub H}]. Using this model, T{sub R}, {alpha}{sub W}, and {eta}{sub CE} can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, …
Date: November 29, 2000
Creator: Stygar, W. A.; Olson, R. E.; Spielman, R. B. & Leeper, R. J.
System: The UNT Digital Library
The determination of the rate of hydrogen generation from transuranic 003 type organic sludge (open access)

The determination of the rate of hydrogen generation from transuranic 003 type organic sludge

None
Date: November 29, 2000
Creator: Barber, D. B.; Carney, K. P. & Demirgian, J. C.
System: The UNT Digital Library
Isotopic germanium targets for high beam current applications at GAMMASPHERE. (open access)

Isotopic germanium targets for high beam current applications at GAMMASPHERE.

The creation of a specific heavy ion residue via heavy ion fusion can usually be achieved through a number of beam and target combinations. Sometimes it is necessary to choose combinations with rare beams and/or difficult targets in order to achieve the physics goals of an experiment. A case in point was a recent experiment to produce {sup 152}Dy at very high spins and low excitation energy with detection of the residue in a recoil mass analyzer. Both to create the nucleus cold and with a small recoil-cone so that the efficiency of the mass analyzer would be high, it was necessary to use the {sup 80}Se on {sup 76}Ge reaction rather than the standard {sup 48}Ca on {sup 108}Pd reaction. Because the recoil velocity of the {sup 152}Dy residues was very high using this symmetric reaction (5% v/c), it was furthermore necessary to use a stack of two thin targets to reduce the Doppler broadening. Germanium targets are fragile and do not withstand high beam currents, therefore the {sup 76}Ge target stacks were mounted on a rotating target wheel. A description of the {sup 76}Ge target stack preparation will be presented and the target performance described.
Date: November 29, 2000
Creator: Greene, J. P. & Lauritsen, T.
System: The UNT Digital Library
Nuclear data needs for non-intrusive inspection. (open access)

Nuclear data needs for non-intrusive inspection.

Various nuclear-based techniques are being explored for use in non-intrusive inspection. Their development is motivated by the need to prevent the proliferation of nuclear weapons, to thwart trafficking in illicit narcotics, to stop the transport of explosives by terrorist organizations, to characterize nuclear waste, and to deal with various other societal concerns. Non-intrusive methods are sought in order to optimize inspection speed, to minimize damage to packages and containers, to satisfy environmental, health and safety requirements, to adhere to legal requirements, and to avoid inconveniencing the innocent. These inspection techniques can be grouped into two major categories: active and passive. They almost always require the use of highly penetrating radiation and therefore are generally limited to neutrons and gamma rays. Although x-rays are widely employed for these purposes, their use does not constitute nuclear technology and therefore is not discussed here. This paper examines briefly the basic concepts associated with nuclear inspection and investigates the related nuclear data needs. These needs are illustrated by considering four of the methods currently being developed and tested.
Date: November 29, 2000
Creator: Smith, D. L. & Michlich, B. J.
System: The UNT Digital Library
On {vert_bar}V{sub ub}{vert_bar} from the Bbar {r_arrow} Xul nu bar dilepton invariant mass spectrum (open access)

On {vert_bar}V{sub ub}{vert_bar} from the Bbar {r_arrow} Xul nu bar dilepton invariant mass spectrum

None
Date: November 29, 2000
Creator: Bauer, Christian W & Luke, Zoltan Ligeti and Michael
System: The UNT Digital Library
Philippines Wind Energy Resource Atlas Development (open access)

Philippines Wind Energy Resource Atlas Development

This paper describes the creation of a comprehensive wind energy resource atlas for the Philippines. The atlas was created to facilitate the rapid identification of good wind resource areas and understanding of the salient wind characteristics. Detailed wind resource maps were generated for the entire country using an advanced wind mapping technique and innovative assessment methods recently developed at the National Renewable Energy Laboratory.
Date: November 29, 2000
Creator: Elliott, D.
System: The UNT Digital Library
Report of the working group on precision measurements - measurements of the W boson mass and width. (open access)

Report of the working group on precision measurements - measurements of the W boson mass and width.

We discuss the prospects for measuring the W mass and width in Run II. The basic techniques used to measure M{sub W} are described and the statistical, theoretical and detector-related uncertainties are discussed in detail. Alternative methods of measuring the W mass at the Tevatron and the prospects for M{sub W} measurements at other colliders are also described.
Date: November 29, 2000
Creator: Brock, R.; Erler, J.; Kim, Y. K.; Marciano, W.; Ashmanskas, W.; Baur, U. et al.
System: The UNT Digital Library
A Sequential Fluid-mechanic Chemical-kinetic Model of Propane HCCI Combustion (open access)

A Sequential Fluid-mechanic Chemical-kinetic Model of Propane HCCI Combustion

We have developed a methodology for predicting combustion and emissions in a Homogeneous Charge Compression Ignition (HCCI) Engine. This methodology combines a detailed fluid mechanics code with a detailed chemical kinetics code. Instead of directly linking the two codes, which would require an extremely long computational time, the methodology consists of first running the fluid mechanics code to obtain temperature profiles as a function of time. These temperature profiles are then used as input to a multi-zone chemical kinetics code. The advantage of this procedure is that a small number of zones (10) is enough to obtain accurate results. This procedure achieves the benefits of linking the fluid mechanics and the chemical kinetics codes with a great reduction in the computational effort, to a level that can be handled with current computers. The success of this procedure is in large part a consequence of the fact that for much of the compression stroke the chemistry is inactive and thus has little influence on fluid mechanics and heat transfer. Then, when chemistry is active, combustion is rather sudden, leaving little time for interaction between chemistry and fluid mixing and heat transfer. This sequential methodology has been capable of explaining the main …
Date: November 29, 2000
Creator: Aceves, S M; Flowers, D L; Martinez-Frias, J; Smith, J R; Westbrook, C; Pitz, W et al.
System: The UNT Digital Library
Temperature calculations of heat loads in rotating target wheels exposed to high beam currents. (open access)

Temperature calculations of heat loads in rotating target wheels exposed to high beam currents.

In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or wobbled beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material.
Date: November 29, 2000
Creator: Greene, J. P.; Gabor, R. & Neubauer, J.
System: The UNT Digital Library
5.2 mW Single-Mode Power from a Coupled-Resonator Vertical-Cavity Laser (open access)

5.2 mW Single-Mode Power from a Coupled-Resonator Vertical-Cavity Laser

None
Date: November 28, 2000
Creator: Fischer, A. J.; Choquette, K. D.; Chow, W. W.; Allerman, A. A. & Geib, K. M.
System: The UNT Digital Library
Charge-Separation Effects in 1.3{micro}m GaAsSb Type II Quantum well Laser Gain (open access)

Charge-Separation Effects in 1.3{micro}m GaAsSb Type II Quantum well Laser Gain

None
Date: November 28, 2000
Creator: Chow, W. W. & Schneider, H. C.
System: The UNT Digital Library