Neutron-induced prompt gamma activation analysis (PGAA) of metalsand non-metals in ocean floor geothermal vent-generated samples (open access)

Neutron-induced prompt gamma activation analysis (PGAA) of metalsand non-metals in ocean floor geothermal vent-generated samples

Neutron-induced prompt gamma activation analysis (PGAA) hasbeen used to analyze ocean floor geothermal vent-generated samples thatare composed of mixed metal sulfides, silicates, and aluminosilicates.The modern application of the PGAA technique is discussed, and elementalanalytical results are given for 25 elements observed in the samples. Theelemental analysis of the samples is consistent with the expectedmineralogical compositions, and very consistent results are obtained forcomparable samples. Special sensitivity to trace quantities of hydrogen,boron, cadmium, dysprosium, gadolinium, and samarium isdiscussed.
Date: December 5, 2002
Creator: Perry, D. L.; Firestone, R. B.; Molnar, G. L.; Revay, Zs.; Kasztovszky, Zs.; Gatti, R. C. et al.
Object Type: Article
System: The UNT Digital Library
TREATMENT OF PLUTONIUM- AND URANIUM-CONTAMINATED OIL FROM ROCKY FLATS ENVIRONMENTAL TECHNOLOGY SITE (open access)

TREATMENT OF PLUTONIUM- AND URANIUM-CONTAMINATED OIL FROM ROCKY FLATS ENVIRONMENTAL TECHNOLOGY SITE

A removal method for plutonium and uranium has been tested at the Rocky Flats Environmental Technology Site (RFETS). This alternative treatment technology is applicable to U.S. Department of Energy (DOE) organics (mainly used pump oil) contaminated with actinides. In our studies, greater than 70% removal of the actinides was achieved. The technology is based on contacting the oil with a sorbent powder consisting of a surface modified mesoporous material. The SAMMS (Self-Assembled Monolayers on Mesoporous Support) technology was developed by the Pacific Northwest National Laboratory for removal and stabilization of RCRA (i.e., lead, mercury, cadmium, silver, etc.) and actinides in water and for removal of mercury from organic solvents [1, 2]. The SAMMS material is based on self-assembly of functionalized monolayers on mesoporous oxide surfaces. The unique mesoporous oxide support provides a high surface area, thereby enhancing the metal-loading capacity. The testing described in this report was conducted on a small scale but larger-scale testing of the technology has been performed on mercury-contaminated oil without difficulty [3].
Date: December 5, 2002
Creator: Klasson, K. T.
Object Type: Report
System: The UNT Digital Library
Preparation of pHEMA-CP composites with high interfacial adhesionvia template-driven mineralization (open access)

Preparation of pHEMA-CP composites with high interfacial adhesionvia template-driven mineralization

We report a template-driven nucleation and mineral growth process for the high-affinity integration of calcium phosphate (CP) with a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel scaffold. A mineralization technique was developed that exposes carboxylate groups on the surface of crosslinked pHEMA, promoting high-affinity nucleation and growth of calcium phosphate on the surface along with extensive calcification of the hydrogel interior. External factors such as the heating rate, the agitation of the mineral stock solution and the duration of the process that affect the outcome of the mineralization were investigated. This template-driven mineralization technique provides an efficient approach toward bonelike composites with high mineral-hydrogel interfacial adhesion strength.
Date: December 5, 2002
Creator: Song, Jie; Saiz, Eduardo & Bertozzi, Carolyn R.
Object Type: Article
System: The UNT Digital Library
Snowmass 2001: Jet energy flow project (open access)

Snowmass 2001: Jet energy flow project

Conventional cone jet algorithms arose from heuristic considerations of LO hard scattering coupled to independent showering. These algorithms implicitly assume that the final states of individual events can be mapped onto a unique set of jets that are in turn associated with a unique set of underlying hard scattering partons. Thus each final state hadron is assigned to a unique underlying parton. The Jet Energy Flow (JEF) analysis described here does not make such assumptions. The final states of individual events are instead described in terms of flow distributions of hadronic energy. Quantities of physical interest are constructed from the energy flow distribution summed over all events. The resulting analysis is less sensitive to higher order perturbative corrections and the impact of showering and hadronization than the standard cone algorithms.
Date: December 5, 2002
Creator: al., C. F. Berger et
Object Type: Article
System: The UNT Digital Library
Raman forward scattering of chirped laser pulses (open access)

Raman forward scattering of chirped laser pulses

Raman scattering of a high-intensity, short duration, frequency-chirped laser pulse propagating in an underdense plasma is examined. The growth of the direct forward scattered light is calculated for a laser pulse with a linear frequency chirp in various spatio-temporal regimes. This includes a previously undescribed regime of strongly-coupled four-wave nonresonant interaction, which is important for relativistic laser intensities. In all regimes of forward scattering, it is shown that the growth rate increases (decreases) for positive (negative) frequency chirp. The effect of chirp on the growth rate is relatively minor, i.e., a few percent chirp yields few percent changes in the growth rates. Numerical solutions based on fully nonlinear cold Maxwell-fluid model are presented which confirm analytical predictions. Relation of these results to recent experiments is discussed.
Date: December 5, 2002
Creator: Schroeder, C. B.; Esarey, E.; Shadwick, B. A. & Leemans, W. P.
Object Type: Article
System: The UNT Digital Library
Development of High Waste Loading Glasses for Advanced Melter Technologies (open access)

Development of High Waste Loading Glasses for Advanced Melter Technologies

The vitrification programs at Hanford and Savannah River may benefit from higher temperature glass formulations that are processable in advanced melters (e.g., induction-heated, cold-crucible melter (ICCM)) or by changing the current liquidus temperature (TL) limit for Joule heated ceramic melters (JHCM). The focus of this report was on the glass formulation activities in support of the ICCM and JHCM demonstrations with C-106/AY-102 simulant. The intent was to provide preliminary (non-optimized) glass formulations for a specific waste stream that met processing requirements, DOE product quality specifications, and programmatic objectives for the two melter types.
Date: December 5, 2002
Creator: Peeler, D.K.
Object Type: Report
System: The UNT Digital Library
Report of the Snowmass T7 working group on high performance computing (open access)

Report of the Snowmass T7 working group on high performance computing

The T7 Working Group on High Performance Computing (HPC) had more than 30 participants. During the three weeks at Snowmass there were about 30 presentations. This working group also had joint sessions with a number of other working groups, including E1 (Neutrino Factories and Muon Colliders), M1 (Muon Based Systems), M6 (High Intensity Proton Sources), T4 (Particle sources), T5 (Beam dynamics), and T8 (Advanced Accelerators). The topics that were discussed fall naturally into three areas: (1) HPC requirements for next-generation accelerator design, (2) state-of-the-art in HPC simulation of accelerator systems, and (3) applied mathematics and computer science activities related to the development of HPC tools that will be of use to the accelerator community (as well as other communities). This document summarizes the material mentioned above and includes recommendations for future HPC activities in the accelerator community. The relationship of those activities to the HENP/SciDAC project on 21st century accelerator simulation is also discussed.
Date: December 5, 2002
Creator: Ko, K.; Ryne, R. & Spentzouris, P.
Object Type: Article
System: The UNT Digital Library
Midwest Transmission Workshop II Summary (open access)

Midwest Transmission Workshop II Summary

OAK-B135 After introductions of all participants, Abby Arnold, RESOLVE, reviewed the purpose of the meeting and the agenda. The purpose of the workshop was to share the results of the Midwest Independent System Operator (MISO) scenario development for wind and other fuel sources and the corresponding implications for transmission throughout the MISO control area. The workshop agenda is included in Attachment A.
Date: December 5, 2002
Creator: Bryan, Kevin
Object Type: Report
System: The UNT Digital Library
Effect of small-scale fractures on flow and transport processes at Yucca Mountain, Nevada (open access)

Effect of small-scale fractures on flow and transport processes at Yucca Mountain, Nevada

Although many conceptual models for fracture-matrix interaction have been evaluated for Yucca Mountain site-characterization studies, the most widely used model is currently based on the dual-permeability concept. It was chosen for use in site-characterization partially because it has proved to be capable of matching many types of field observed data. Another consideration is that net infiltration rates at the site are estimated to be very low (on the order of millimeters/year), or close to saturated matrix hydraulic conductivity. Recent field studies and tests, in particular, fracture mapping data, collected along the walls of the underground tunnels reveal that there exists a significantly large variety in fracture sizes from centimeters to tens of meters. There is a considerable amount of small-scale fractures that have not been considered in the previous modeling studies. Although the majority of these small fractures may not contribute much to global flow and transport through the fracture-matrix system, they may provide large amounts of storage pore space and allow for additional connection areas for well-connected, large-scale fractures and surrounding matrix blocks, which ultimately affect fracture-matrix interactions. However, the currently used dual-permeability model is unable to include the potentially important effect of small fractures. To overcome the limitations …
Date: December 5, 2002
Creator: Wu, Yu-Shu; Liu, H.H. & Bodvarsson, G.S.
Object Type: Article
System: The UNT Digital Library
K (transverse) jet algorithms in hadron colliders: The D0 experience (open access)

K (transverse) jet algorithms in hadron colliders: The D0 experience

D0 has implemented and studied a k{sub {perpendicular}} jet algorithm for the first time in a hadron collider. The authors have submitted two physics results for publication: the subjet multiplicity in quark and gluon jets and the central inclusive jet cross section measurements. A third result, a measurement of thrust distributions in jet events, is underway. A combination of measurements using several types of algorithms and samples taken at different center-of-mass energies is desirable to understand and distinguish with higher accuracy between instrumentation and physics effects.
Date: December 5, 2002
Creator: Elvira, V. Daniel
Object Type: Article
System: The UNT Digital Library
A cosmic perspective from Lapland in 2001 (open access)

A cosmic perspective from Lapland in 2001

A convergence of ideas, observations and technology have led to the greatest period of cosmological discovery yet. Over the past three years we have determined the basic features of our Universe. We are now challenged to make sense of what we have found. The outcome of planned experiments and observations as well as new ideas will be required. If we succeed, ours truly will be a Golden Age of Cosmology.
Date: December 5, 2002
Creator: Turner, Michael s.
Object Type: Article
System: The UNT Digital Library
Report of the Snowmass T4 working group on particle sources: Positron sources, anti-proton sources and secondary beams (open access)

Report of the Snowmass T4 working group on particle sources: Positron sources, anti-proton sources and secondary beams

This report documents the activities of the Snowmass 2001 T4 Particle Sources Working Group. T4 was charged with examining the most challenging aspects of positron sources for linear colliders and antiproton sources for proton-antiproton colliders, and the secondary beams of interest to the physics community that will be available from the next generation of high-energy particle accelerators. The leading issues, limiting technologies, and most important R and D efforts of positron production, antiproton production, and secondary beams are discussed in this paper. A listing of T4 Presentations is included.
Date: December 5, 2002
Creator: al., N. Mokhov et
Object Type: Article
System: The UNT Digital Library
Parameters of an E+ E- collider in the VLHC tunnels (open access)

Parameters of an E+ E- collider in the VLHC tunnels

The authors have discussed the option of building an e{sup +}e{sup -} collider in the tunnels of the VLHC in a number of notes [1,2,3,4,5]. Continued study of this option has shown that the operating range of the machine can be extended somewhat from previous papers and this note presents the most recent progress on the luminosity and high energy operation of this machine. They have assumed that this machine would be used to justify the construction of a tunnel which would eventually house the VLHC collider, and perhaps ultimately an ep collider.
Date: December 5, 2002
Creator: al., T. Sen et
Object Type: Article
System: The UNT Digital Library
Merged Source Word Codes for Efficient, High-Speed Entropy Coding (open access)

Merged Source Word Codes for Efficient, High-Speed Entropy Coding

We present our work on fast entropy coders for binary messages utilizing only bit shifts and table lookups. To minimize code table size we limit our code lengths with a novel type of variable-to-variable (VV) length code created from source word merging. We refer to these codes as merged codes. With merged codes it is possible to achieve a desired level of efficiency by adjusting the number of bits read from the source at each step. The most efficient merged codes yield a coder with an inefficiency of 0.4%, relative to the Shannon entropy, in the worst case. On one of our test systems a current implementation of coder using merged codes has a throughput of 35 Mbytes/sec.
Date: December 5, 2002
Creator: Senecal, J; Joy, K & Duchaineau, M
Object Type: Article
System: The UNT Digital Library
Rate Equation Theory for Island Sizes and Capture Zone Areas in Submonolayer Deposition: Realistic Treatment of Spatial Aspects of Nucleation (open access)

Rate Equation Theory for Island Sizes and Capture Zone Areas in Submonolayer Deposition: Realistic Treatment of Spatial Aspects of Nucleation

Extensive information on the distribution of islands formed during submonolayer deposition is provided by the joint probability distribution (JPD) for island sizes, s, and capture zone areas, A. A key ingredient determining the form of the JPD is the impact of each nucleation event on existing capture zone areas. Combining a realistic characterization of such spatial aspects of nucleation with a factorization ansatz for the JPD, we provide a concise rate equation formulation for the variation with island size of both the capture zone area and the island density.
Date: December 5, 2002
Creator: Evans, J. W.; Li, M. & Bartelt, M. C.
Object Type: Article
System: The UNT Digital Library
New Trends in Induction Accelerator Technology (open access)

New Trends in Induction Accelerator Technology

Recent advances in solid-state modulators now permit the design of a new class of high current accelerators. These new accelerators will be able to operate in burst mode at frequencies of several MHz with unprecedented flexibility and precision in pulse format. These new modulators can drive accelerators to high average powers that far exceed those of any other technology and can be used to enable precision beam manipulations. New insulator technology combined with novel pulse forming lines and switching may enable the construction of a new type of high gradient, high current accelerator. Recent developments in these areas will be reviewed.
Date: December 5, 2002
Creator: Caporaso, G J
Object Type: Article
System: The UNT Digital Library
Accelerator physics and technology limitations to ultimate energy and luminosity in very large hadron colliders (open access)

Accelerator physics and technology limitations to ultimate energy and luminosity in very large hadron colliders

The following presents a study of the accelerator physics and technology limitations to ultimate energy and luminosity in very large hadron colliders (VLHCs). The main accelerator physics limitations to ultimate energy and luminosity in future energy frontier hadron colliders are synchrotron radiation (SR) power, proton-collision debris power in the interaction regions (IR), number of events-per-crossing, stored energy per beam and beam-stability [1]. Quantitative estimates of these limits were made and translated into scaling laws that could be inscribed into the particle energy versus machine size plane to delimit the boundaries for possible VLHCs. Eventually, accelerator simulations were performed to obtain the maximum achievable luminosities within these boundaries. Although this study aimed at investigating a general VLHC, it was unavoidable to refer in some instances to the recently studied, [2], 200 TeV center-of-mass energy VLHC stage-2 design (VLHC-2). A more thorough rendering of this work can be found in [3].
Date: December 5, 2002
Creator: al., P. Bauer et
Object Type: Article
System: The UNT Digital Library
Cesium-137 in the Sediments of Fourmile Creek (open access)

Cesium-137 in the Sediments of Fourmile Creek

The Nonproliferation Technology Section (NTS) was requested by the Environmental Restoration Division (ER) to aid in completing ground-truth measurements of aerial overflight data in support of the Integrator Operable Unit (IOU) program at the Savannah River Site (SRS). The IOU's at the SRS are under investigation as a possible pathway for the release of contamination from past SRS activities to off-unit receptors and the environment. The IOU's are defined as surface water bodies and associated wetlands, including the water, sediment and related biota. The objective of the IOU program is to: assess the risk to potential human and ecological receptors from IOU contamination; evaluate the impact of inactive and active waste units and operating facilities on the IOU quality; determine if IOU early actions, including reprioritization of operable units implementation schedules, are necessary; and complete the remedial investigation/feasibility study process, defining the nature and extent of IOU contamination, remedial action objectives, and final remediation goals.
Date: December 5, 2002
Creator: Beals, D.M.
Object Type: Report
System: The UNT Digital Library
The precision of higgs boson measurements and their implications (open access)

The precision of higgs boson measurements and their implications

The prospects for a precise exploration of the properties of a single or many observed Higgs bosons at future accelerators are summarized, with particular emphasis on the abilities of a Linear Collider (LC). Some implications of these measurements for discerning new physics beyond the Standard Model (SM) are also discussed.
Date: December 5, 2002
Creator: Conway, J.; Desch, K.; Gunion, J. F.; Mrenna, S. & Zeppenfeld, D.
Object Type: Article
System: The UNT Digital Library