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Analytical Model for Prediction of Plate-Specific Fracture Toughness Properties of ASTM A285 Steel (open access)

Analytical Model for Prediction of Plate-Specific Fracture Toughness Properties of ASTM A285 Steel

A materials test program was developed to measure mechanical properties of A285 carbon steel under conditions relevant to waste storage tanks at the Savannah River Site.
Date: December 19, 2002
Creator: Subramanian, K.H.
System: The UNT Digital Library
B physics, BTeV, and all that (open access)

B physics, BTeV, and all that

The status of ''flavor physics'' in our pursuit of knowledge in elementary particle physics is discussed. Then, the BTeV experiment, planned for the Fermilab Tevatron collider, is described briefly and its physics reach is discussed. Comparisons are made to the current B physics experiments at e{sup +}e{sup -} facilities and to the LHCb experiment, planned for the Large Hadron Collider at CERN.
Date: December 19, 2002
Creator: Butler, Joel N.
System: The UNT Digital Library
Detrimental Effects of Natural Vertical Head Gradients on Chemical and Water Level Measurements in Observation Wells: Identification and Control (open access)

Detrimental Effects of Natural Vertical Head Gradients on Chemical and Water Level Measurements in Observation Wells: Identification and Control

It is well known that vertical head gradients exist in natural aquifer systems, and borehole flowmeter data have shown that such gradients commonly set up spontaneous vertical flows in monitoring wells, often called ambient flows. What has not been fully appreciated until recently is the serious detrimental effects such flows can have on solute concentration and hydraulic head measurements in monitoring wells. This communication explores the possibilities of diminishing ambient flows by increasing the hydraulic resistance to vertical flow within monitoring wells and limiting the penetration of such wells. Analyzed also are the surprising effects that vertical gradients may have on the equilibrium water level in a monitoring well. Results are based on collected data, numerical flow simulations, and hydraulic analysis in the near-well vicinity.
Date: December 19, 2002
Creator: Flach, G. P.
System: The UNT Digital Library
Development of the LBNL positron emission mammography camera (open access)

Development of the LBNL positron emission mammography camera

We present the construction status of the LBNL Positron Emission Mammography (PEM) camera, which utilizes a PET detector module with depth of interaction measurement consisting of 64 LSO crystals (3x3x30 mm3) coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PDs). The PMT provides an accurate timing pulse, the PDs identify the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction. We have completed construction of all 42 PEM detector modules. All data acquisition electronics have been completed, fully tested and loaded onto the gantry. We have demonstrated that all functions of the custom IC work using the production rigid-flex boards and data acquisition system. Preliminary detector module characterization and coincidence data have been taken using the production system, including initial images.
Date: December 19, 2002
Creator: Huber, Jennifer S.; Choong, Woon-Seng; Wang, Jimmy; Maltz, Jonathon S.; Qi, Jinyi; Mandelli, Emanuele et al.
System: The UNT Digital Library
First CDF II heavy flavor physics results with the silicon vertex trigger (open access)

First CDF II heavy flavor physics results with the silicon vertex trigger

The renewed CDF II experiment recently re-started data taking. The data collected lately already provides insight in the heavy flavor capabilities of this p{bar p} experiment. As a benchmark of these possibilities we present two preliminary results: the measurement of the branching fractions BR(D{sup o} {yields} {pi}{sup +}{pi}{sup -}) and BR(D{sup o} {yields} K{sup +}K{sup -}) relative to BR(D{sup o} {yields} K{sup {+-}} {pi}{sup {-+}}) and the measurement of the invariant mass difference between D{sub s}{sup {+-}} {yields} {phi}{pi}{sup {+-}}, {phi} {yields} K{sup +}K{sup -} and D{sup {+-}} {yields} {phi}{pi}{sup {+-}}, {phi} {yields} K{sup +}K{sup -}. The preliminary results are BR(D{sup o} {yields} {pi}{sup +}{pi}{sup -})/BR(D{sup o} {yields} K{sup {+-}} {pi}{sup {-+}}) = 3.37 {+-} 0.20(stat) {+-} 0.16(sys)%, BR(D{sup o} {yields} K{sup +}K{sup -})/BR(D{sup o} {yields} K{sup {+-}} {pi}{sup {-+}}) = 11.17 {+-} 0.98(sys) % and {Delta}m (D{sub s} - D{sup +}) = 99.28 {+-} 0.43(stat) {+-} 0.27(sys) MeV/c{sup 2}. All results are consistent with PDG expectations.
Date: December 19, 2002
Creator: Cerri, A.
System: The UNT Digital Library
Investigation of the Corrosivity of the Vapor Phase over High-Level Radioactive Waste (open access)

Investigation of the Corrosivity of the Vapor Phase over High-Level Radioactive Waste

Corrosion in the vapor space and at the liquid/air interface of the Department of Energy high level waste tanks have emerged as a potentially aggressive degradation mechanism.
Date: December 19, 2002
Creator: Subramanian, K.H.
System: The UNT Digital Library
On leakage and seepage from geologic carbon sequestration sites: Unsaturated Zone Attenuation (open access)

On leakage and seepage from geologic carbon sequestration sites: Unsaturated Zone Attenuation

None
Date: December 19, 2002
Creator: Oldenburg, Curtis M. & Unger, Andre J. A.
System: The UNT Digital Library
The QCD string spectrum and conformal field theory (open access)

The QCD string spectrum and conformal field theory

The low energy excitation spectrum of the critical Wilson surface is discussed between the roughening transition and the continuum limit of lattice QCD. The fine structure of the spectrum is interpreted within the framework of two-dimensional conformal field theory.
Date: December 19, 2002
Creator: Juge, Keisuke Jimmy; Kuti, Julius & Morningstar, Colin
System: The UNT Digital Library
A trickle turns into a flood: Standby power loss in China (open access)

A trickle turns into a flood: Standby power loss in China

None
Date: December 19, 2002
Creator: Lin, Jiang
System: The UNT Digital Library
Condition for production of circulating proton beam with intensity greater than space charge limit. (open access)

Condition for production of circulating proton beam with intensity greater than space charge limit.

Transverse e-p instability in proton rings could be damped by increasing the beam density and the rate of secondary particles production above the threshold level, with the corresponding decrease of unstable wavelength {lambda} below the transverse beam size h (increase of beam density n{sub b} and ion density n{sub i} above the threshold level: n{sub b} + n{sub i} > {beta}{sup 2}/(r{sub e} h{sup 2}), where r{sub e} = e{sup 2}/mc{sup 2}). Such island of stability can be reached by a fast charge-exchange injection without painting and enhanced generation of secondary plasma, which was demonstrated in a small scale Proton Storage Ring (PSR) at the Institute of Nuclear Physics, Novosibirsk, Russia. With successful damping of e-p instability, the intensity of circulating proton beam, with a space charge neutralization was increased up to 6 times above a space charge limit. Corresponding tune shift without space charge neutralization should be up to {Delta}v=0.85 x 6 (in the ring with v = 0.85). In this paper, they review experimental observations of transverse instability of proton beams in various rings. they also discuss methods which can be used to damp the instability. Such experimental data could be useful for verification of computer simulation tools …
Date: November 19, 2002
Creator: Dudnikov, Vadim
System: The UNT Digital Library
A cost optimized small aperture 2 in 1 VLHC (open access)

A cost optimized small aperture 2 in 1 VLHC

The costing algorithm used here was started at the time of the SSC proposal, was updated and presented at the Port Jefferson VLHC meeting in october 2000, and has been slightly modified again for this study. The method starts from a specified central field and aperture, and uses approximate formulae to design the dipole magnet cross sections. The required masses of superconductor, stabilizing copper, support stainless steel, and yoke are calculated, and the surface area of the cold mass determined. Costs per unit weight, or area/temperature, are assigned for each item and a linear cost added to cover the tunnel, supports, magnet ends, correctors, quadrupoles, survey etc. The unit costs were originally extracted from the SSC estimates, but have been inflated and modified since. They have no Intersection Point magnets, detectors, detector halls, EDIA, contingency, R and D or escalation. The assumed linear cost, including magnet ends, with the inflation factor, is 22 k$/m. If the aperture is small, as in the pipeatron, the magnets can be long, end costs reduced, and the packing factor improved. This expectation is confirmed by the recent Fermilab VLHC study. Using the total estimate from this study, the algorithm has been modified to include …
Date: November 19, 2002
Creator: Palmer, R. B.; Parker, B. & Foster, G. W.
System: The UNT Digital Library
Cross-Section Measurements with the Radioactive Isotope Accelerator (RIA) (open access)

Cross-Section Measurements with the Radioactive Isotope Accelerator (RIA)

RIA will produce beams of exotic nuclei of unprecedented luminosity. Preliminary studies of the feasibility of measuring cross-sections of interest to the science based stockpile stewardship (SBSS) program will be presented, and several experimental techniques will be discussed. Cross-section modeling attempts for the A = 95 mass region will be shown. In addition, several radioactive isotopes could be collected for target production or medical isotope purposes while the main in-beam experiments are running. The inclusion of a broad range mass analyzer (BRAMA) capability at RIA will enable more effective utilization of the facility, enabling the performance of multiple experiments at the same time. This option will be briefly discussed.
Date: November 19, 2002
Creator: Stoyer, M A; Moody, K J; Wild, J F; Patin, J B; Shaughnessy, D A; Stoyer, N J et al.
System: The UNT Digital Library
Dark matter and dark energy: The critical questions (open access)

Dark matter and dark energy: The critical questions

Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% {+-} 1% baryons; 29% {+-} 4% cold dark matter; and 66% {+-} 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand it. The critical questions are: (1) What form do the dark baryons take? (2) What is (are) the constituent(s) of the cold dark matter? (3) What is the nature of the mysterious dark energy that is causing the Universe to speed up.
Date: November 19, 2002
Creator: Turner, Michael S.
System: The UNT Digital Library
Hierarchical Representation of Time-Varying Volume Data with Fourth-Root-of-Two Subdivision and Quadrilinear B-Spline Wavelets (open access)

Hierarchical Representation of Time-Varying Volume Data with Fourth-Root-of-Two Subdivision and Quadrilinear B-Spline Wavelets

Multiresolution methods for representing data at multiple levels of detail are widely used for large-scale two- and three-dimensional data sets. We present a four-dimensional multiresolution approach for time-varying volume data. This approach supports a hierarchy with spatial and temporal scalability. The hierarchical data organization is based on 4{radical}2 subdivision. The n{radical}2-subdivision scheme only doubles the overall number of grid points in each subdivision step. This fact leads to fine granularity and high adaptivity, which is especially desirable in the spatial dimensions. For high-quality data approximation on each level of detail, we use quadrilinear B-spline wavelets. We present a linear B-spline wavelet lighting scheme based on n{radical}2 subdivision to obtain narrow masks for the update rules. Narrow masks provide a basis for out-of-core data exploration techniques and view-dependent visualization of sequences of time steps.
Date: November 19, 2002
Creator: Linsen, Lars; Pascucci, Valerio; Duchaineau, Mark A.; Hamann, Bernd & Joy, Kenneth I.
System: The UNT Digital Library
Interactive View-Dependent Rendering of Large Isosurfaces (open access)

Interactive View-Dependent Rendering of Large Isosurfaces

We present an algorithm for interactively extracting and rendering isosurfaces of large volume datasets in a view-dependent fashion. A recursive tetrahedral mesh refinement scheme, based on longest edge bisection, is used to hierarchically decompose the data into a multiresolution structure. This data structure allows fast extraction of arbitrary isosurfaces to within user specified view-dependent error bounds. A data layout scheme based on hierarchical space filling curves provides access to the data in a cache coherent manner that follows the data access pattern indicated by the mesh refinement.
Date: November 19, 2002
Creator: Gregorski, B; Duchaineau, M; Lindstrom, P; Pascucci, V & Joy, K I
System: The UNT Digital Library
Making sense of the new cosmology (open access)

Making sense of the new cosmology

Over the past three years we have determined the basic features of the Universe--spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos; and apparently born from a burst of rapid expansion during which quantum noise was stretched to astrophysical size seeding cosmic structure. The New Cosmology greatly extends the highly successful hot big-bang model. Now we have to make sense of all this: What is the dark matter particle? What is the nature of the dark energy? Why this mixture? How did the matter, antimatter asymmetry arise? What is the underlying cause of inflation (if it indeed occurred)?
Date: November 19, 2002
Creator: Turner, Michael S.
System: The UNT Digital Library
Modification of the Coherence Properties of a Laser Beam Propagating through a Plasma and its Consequences for Stimulated Scattering Instabilities (open access)

Modification of the Coherence Properties of a Laser Beam Propagating through a Plasma and its Consequences for Stimulated Scattering Instabilities

The control of coherence is a critical issue for the high-power lasers used in inertial confinement fusion (ICF). The level of coherence is an important parameter for the control of the light intensity distribution as well as the growth rate of parametric instabilities. Over the past few years, experimental and theoretical studies have evidenced the ability of an underdense plasma to reduce the spatial and temporal coherence of an intense laser beam propagating through it. As any process affecting laser propagation, plasma-induced incoherence appears fundamental for ICF for it can impact on wave-coupling conditions. We present results obtained with the six-beam LULI laser facility, in the nanosecond regime, showing direct evidences of the reduction of spatial and temporal coherence of an initially RPP-smoothed laser beam after propagation through a preformed plasma. Plasma induced incoherence (PII) proceeds from several mechanisms which include self-focusing and filament instabilities and non-linear coupling between self-focusing and forward stimulated Brillouin scattering (FSBS). Part of these experiments was dedicated to the understanding of the physical mechanisms involved in PII, as the break up of a single hot spot and the existence of ion acoustic waves having small wave vectors transverse to the interaction beam which are produced …
Date: November 19, 2002
Creator: Labaune, C.; Baldis, H. A.; Bandulet, H.; Depierreux, S.; Fuchs, J.; Michel, P. et al.
System: The UNT Digital Library
The new cosmology (open access)

The new cosmology

Over the past three years we have determined the basic features of our Universe. It is spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos; and it apparently began from a great burst of expansion during which quantum noise was stretched to astrophysical size seeding cosmic structure. This ''New Cosmology'' greatly extends the highly successful hot big-bang model. Now we have to make sense of it. What is the dark matter particle? What is the nature of the dark energy? Why this mixture? How did the matter, antimatter asymmetry arise? What is the underlying cause of inflation (if it indeed occurred)?
Date: November 19, 2002
Creator: Turner, Michael S.
System: The UNT Digital Library
Report of the subgroup on alternative models and new ideas (open access)

Report of the subgroup on alternative models and new ideas

We summarize some of the work done by the P3 subgroup on Alternative Models and New Ideas. The working group covered a broad range of topics including a constrained Standard Model from an extra dimension, a discussion of recent ideas addressing the strong CP problem, searches for doubly charged higgs bosons in e{gamma} collisions, and an update on discovery limits for extra neutral gauge bosons at hadron colliders. The breadth of topics rejects the many ideas and approaches to physics beyond the Standard Model.
Date: November 19, 2002
Creator: Chertok, M.; Dienes, K.; Godfrey, S.; Kalyniak, P.; Kaplan, D.; Kribs, G. D. et al.
System: The UNT Digital Library
Summary of radiation damage studies on rare earth permanent magnets (open access)

Summary of radiation damage studies on rare earth permanent magnets

With the proposed use of permanent magnets for both the NLC and the VLHC the issue flux loss due to radiation damage needs to be fully understood. There exist many papers on the subject. There are many difficulties in drawing conclusions from all of these data. First there is the difference methods of dosimetry, second different types of magnets and magnetic arrangements, and third different manufacturers of magnet material. This paper provides a summary of the existing literature on the subject.
Date: November 19, 2002
Creator: Volk, J. T.
System: The UNT Digital Library
T2 working group summary report (open access)

T2 working group summary report

The T2 Working Group has reviewed and discussed the issues and challenges of a wide range of magnet technologies: superconducting magnets using NbTi, Nb{sub 3}Sn and HTS conductor with fields ranging from 2-15 T and permanent magnets up to 4 T. The development time of these technologies varies significantly, but all are considered viable, providing an unprecedented variety of choice that can be determined by a balance of cost and application requirements. One of the most significant advances since Snowmass '96 is the increased development and utilization of Nb{sub 3}Sn. All of the current US magnet programs (BNL, FNAL, LBNL, and Texas A and M) have programs using Nb{sub 3}Sn. There are also active programs in HTS development at BNL and LBNL. A DOE/HEP sponsored program to increase the performance and reduce the cost of Nb{sub 3}Sn is in its second year. The program has already made significant advances. The current funding for this program is $500k/year and an increase to $2M has been proposed for FY02.
Date: November 19, 2002
Creator: al., S. Caspi et
System: The UNT Digital Library
A Dynamically Adaptive Arbitrary Lagrangian-Eulerian Method for Hydrodynamics (open access)

A Dynamically Adaptive Arbitrary Lagrangian-Eulerian Method for Hydrodynamics

A new method that combines staggered grid Arbitrary Lagrangian-Eulerian (ALE) techniques with structured local adaptive mesh refinement (AMR) has been developed for solution of the Euler equations. The novel components of the combined ALE-AMR method hinge upon the integration of traditional AMR techniques with both staggered grid Lagrangian operators as well as elliptic relaxation operators on moving, deforming mesh hierarchies. Numerical examples demonstrate the utility of the method in performing detailed three-dimensional shock-driven instability calculations.
Date: October 19, 2002
Creator: Anderson, R W; Pember, R B & Elliott, N S
System: The UNT Digital Library
938 nm Nd-Doped High Power Cladding Pumped Fiber Amplifier (open access)

938 nm Nd-Doped High Power Cladding Pumped Fiber Amplifier

2.1W of 938nm light has been produced in an Nd{sup 3+} doped fiber amplifier. Wavelength dependent bend losses can be employed to minimize 1088nm amplified spontaneous emission giving the optical fiber a distinct advantage over bulk media.
Date: September 19, 2002
Creator: Dawson, J; Beach, R; Drobshoff, A; Liao, Z; Pennington, D; Payne, S et al.
System: The UNT Digital Library
2D/3D quench simulation using ANSYS for epoxy impregnated Nb3Sn high field magnets (open access)

2D/3D quench simulation using ANSYS for epoxy impregnated Nb3Sn high field magnets

A quench program using ANSYS is developed for the high field collider magnet for three-dimensional analysis. Its computational procedure is explained. The quench program is applied to a one meter Nb{sub 3}Sn high field model magnet, which is epoxy impregnated. The quench simulation program is used to estimate the temperature and mechanical stress inside the coil as well as over the whole magnet. It is concluded that for the one meter magnet with the presented cross section and configuration, the thermal effects due to the quench is tolerable. But we need much more quench study and improvements in the design for longer magnets.
Date: September 19, 2002
Creator: al., Ryuji Yamada et
System: The UNT Digital Library