30 years of high-intensity negative ion sources for accelerators (open access)

30 years of high-intensity negative ion sources for accelerators

Thirty years ago, July 1, 1971, significant enhancement of negative ion emission from a gas discharge following an admixture of cesium was observed for the first time. This observation became the basis for the development of Surface Plasma Sources (SPS) for efficient production of negative ions from the interaction of plasma particles with electrodes on which adsorbed cesium reduced the surface work-function. The emission current density of negative ions increased rapidly from j {approximately} 10 mA/cm{sup 2} to 3.7 A/cm{sup 2} with a flat cathode and up to 8 A/cm{sup 2} with an optimized geometrical focusing in the long pulse SPS, and to 0.3 A/cm{sup 2} for DC SPS, recently increased up to 0.7 A/cm{sup 2}. Discovery of charge-exchange cooling helped decrease the negative ion temperature T below 1 eV, and increase brightness by many orders to a level compatible with the best proton sources, B = j/T> 1 A/cm{sup 2} eV. The combination of the SPS with charge-exchange injection improved large accelerators operation and has permitted beam accumulation up to space-charge limit and overcome this limit several times. The early SPS for accelerators have been in operation without modification for {approximately} 25 years. Advanced version of the SPS for …
Date: July 25, 2001
Creator: Dudnikov, Vadim
Object Type: Article
System: The UNT Digital Library
A 75-keV, 145-mA PROTON INJECTOR (open access)

A 75-keV, 145-mA PROTON INJECTOR

None
Date: July 1, 2001
Creator: Sherman, J. D.; Figueroa, T. L. & Al, Et
Object Type: Article
System: The UNT Digital Library
2001 Gordon Research Conference on Applied and Environmental Microbiology. Final progress report [agenda and attendee list] (open access)

2001 Gordon Research Conference on Applied and Environmental Microbiology. Final progress report [agenda and attendee list]

The Gordon Research Conference on Applied and Environmental Microbiology was held at Connecticut College, New London, Connecticut, July 22-27, 2001. The conference was attended by 121 participants. The attendees represented the spectrum of endeavor in this field, coming from academia, industry, and government laboratories, and included US and foreign scientists, senior researchers, young investigators, and students. Emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate discussion about the key issues in the field today. Session topics included the following: Environmental and applied genomics, Cell-to-cell signaling and multicellular behavior, Emerging technologies and methods, Novel metabolisms and ecosystems, Directed evolution of enzymes and pathways, Symbiotic and trophic relationships, Synthesis and application of novel biopolymers, and Microbes at the oxic-anoxic interface. There was also a special lecture titled ''Under the umbrella of the big tree: microbial biology into the 21st century.''
Date: July 26, 2001
Creator: Drake, Harold
Object Type: Report
System: The UNT Digital Library
2001 Gordon Research Conference on Laser Diagnostics in Combustion. Final Progress Report (open access)

2001 Gordon Research Conference on Laser Diagnostics in Combustion. Final Progress Report

None
Date: July 6, 2001
Creator: unknown
Object Type: Article
System: The UNT Digital Library
2001 Gordon Research Conference on Organometallic Chemistry. Final progress report [agenda and attendee list] (open access)

2001 Gordon Research Conference on Organometallic Chemistry. Final progress report [agenda and attendee list]

The Gordon Research Conference on Organometallic Chemistry was held at Salve Regina University, Newport, Rhode Island, July 22-27, 2001. The conference had 133 participants. The attendees represented the spectrum of endeavor in this field, coming from academia, industry, and government laboratories, and included US and foreign scientists, senior researchers, young investigators, and students. Emphasis was place on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions; poster sessions were held.
Date: July 27, 2001
Creator: Burns, Carol
Object Type: Report
System: The UNT Digital Library
2001 Gordon Research Conference on Photoions, Photoionization and Photodetachment. Final progress report [agenda and attendees list] (open access)

2001 Gordon Research Conference on Photoions, Photoionization and Photodetachment. Final progress report [agenda and attendees list]

The Gordon Research Conference on Photoions, Photoionization and Photodetachment was held at Williams College, Williamstown, Massachusetts, July 8-13, 2001. The 72 conference attendees represented the spectrum of endeavor in this field, coming from academia, industry, and government laboratories, and including US and foreign scientists, senior researchers, young investigators, and students. Emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate discussion about the key issues in the field today. Time for formal presentations was limited. Sessions included the following topics: Vibrational structure, Time resolved studies: nuclear wavepackets, Valence photoionization, Clusters and networks, Resonance structures and decay mechanisms, Ultrafast photoionization, Threshold photoionization, Molecule fixed properties, and Collisional phenomena.
Date: July 13, 2001
Creator: Johnson, Mark
Object Type: Report
System: The UNT Digital Library
ABSOLUTE PARTIAL GAMMA-RAY CROSS SECTIONS IN 238U(n,xngamma) REACTIONS (open access)

ABSOLUTE PARTIAL GAMMA-RAY CROSS SECTIONS IN 238U(n,xngamma) REACTIONS

None
Date: July 1, 2001
Creator: Fotiadis, N.; Johns, G. & Al, Et
Object Type: Article
System: The UNT Digital Library
Accurate Hydrogen Depth Profiling by Reflection Elastic Recoil Detection Analysis (open access)

Accurate Hydrogen Depth Profiling by Reflection Elastic Recoil Detection Analysis

None
Date: July 1, 2001
Creator: Verda, R. D.; Tesmer, J. R. & Al, Et
Object Type: Article
System: The UNT Digital Library
Acoustical Imaging and Mechanical Properties of Soft Rock and Marine Sediments Progress Report: April-June 2001 (open access)

Acoustical Imaging and Mechanical Properties of Soft Rock and Marine Sediments Progress Report: April-June 2001

Mechanically weak formations, such as chalks, high porosity sandstones, and marine sediments, pose significant problems for oil and gas operators. Problems such as compaction, subsidence, and loss of permeability can affect reservoir production operations. For example, the unexpected subsidence of the Ekofisk chalk in the North Sea required over one billion dollars to re-engineer production facilities to account for losses created during that compaction (Sulak 1991). Another problem in weak formations is that of shallow water flows (SWF). Deep water drilling operations sometimes encounter cases where the marine sediments, at shallow depths just below the seafloor, begin to uncontrollably flow up and around the drill pipe. SWF problems created a loss of $150 million for the Ursa development project in the U.S. Gulf Coast SWF (Furlow 1998a,b; 1999a,b). The goal of this project is to provide a database on both the rock mechanical properties and the geophysical properties of weak rocks and sediments. These could be used by oil and gas companies to detect, evaluate, and alleviate potential production and drilling problems. The results will be useful in, for example, pre-drill detection of events such as SWF's by allowing a correlation of seismic data (such as hazard surveys) to rock …
Date: July 1, 2001
Creator: Scott, Thurman E., Jr.; Abousleiman, Younane & Zaman, Musharraf
Object Type: Report
System: The UNT Digital Library
Adaptive Optics Control Strategies for Extremely Large Telescopes (open access)

Adaptive Optics Control Strategies for Extremely Large Telescopes

Adaptive optics for the 30-100 meter class telescopes now being considered will require an extension in almost every area of AO system component technology. In this paper, we present scaling laws and strawman error budgets for AO systems on extremely large telescopes (ELTs) and discuss the implications for component technology and computational architecture. In the component technology area, we discuss the advanced efforts being pursued at the NSF Center for Adaptive Optics (CfAO) in the development of large number of degrees of freedom deformable mirrors, wavefront sensors, and guidestar lasers. It is important to note that the scaling of present wavefront reconstructor algorithms will become computationally intractable for ELTs and will require the development of new algorithms and advanced numerical mathematics techniques. We present the computational issues and discuss the characteristics of new algorithmic approaches that show promise in scaling to ELT AO systems.
Date: July 26, 2001
Creator: Gavel, D T
Object Type: Article
System: The UNT Digital Library
ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS (SBCR) (open access)

ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS (SBCR)

This report summarizes the accomplishment made during the second year of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals. The technical difficulties that were encountered in implementing Computer Automated Radioactive Particle Tracking (CARPT) in high pressure SBCR have been successfully resolved. New strategies for data acquisition and calibration procedure have been implemented. These have been performed as a part of other projects supported by Industrial Consortium and DOE via contract DE-2295PC95051 which are executed in parallel with this grant. CARPT and Computed Tomography (CT) experiments have been performed using air-water-glass beads in 6 inch high pressure stainless steel slurry bubble column reactor at selected conditions. Data processing of this work is in progress. The overall gas holdup and the hydrodynamic parameters are measured by Laser Doppler Anemometry (LDA) in 2 inch slurry bubble column using Norpar 15 that mimic at room temperature the Fischer Tropsch wax at FT reaction conditions of high pressure and temperature. To improve the design and scale-up of bubble column, new correlations have been developed to predict the radial gas holdup and the time averaged axial liquid recirculation velocity profiles in bubble columns.
Date: July 25, 2001
Creator: Al-Dahhan, M.H.; Dudukovic, M.P. & Fan, L.S.
Object Type: Report
System: The UNT Digital Library
ADVANCED GAS TURBINE SYSTEMS RESEARCH PROGRAM (open access)

ADVANCED GAS TURBINE SYSTEMS RESEARCH PROGRAM

The quarterly activities of the Advanced Gas Turbine Systems Research (AGTSR) program are described in this quarterly report. As this program administers research, we have included all program activity herein within the past quarter as dated. More specific research progress reports are provided weekly at the request of the AGTSR COR and are being sent to NETL. As for the administration of this program, items worthy of note are presented in extended bullet format following the appropriate heading.
Date: July 1, 2001
Creator: Golan, Lawrence P.
Object Type: Report
System: The UNT Digital Library
Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants (open access)

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants

Eltron Research Inc., and team members, are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, ceramic, cermet (ceramic/metal), and thin film membranes were prepared, characterized, and evaluated for H{sub 2} transport. For selected ceramic membrane compositions an optimum range for transition metal doping was identified, and it was determined that highest proton conductivity occurred for two-phase ceramic materials. Furthermore, a relationship between transition metal dopant atomic number and conductivity was observed. Ambipolar conductivities of {approx}6 …
Date: July 30, 2001
Creator: Roark, Shane E.; Sammells, Tony F.; Mackay, Richard A.; Calihman, Adam E.; Pitzman, Lyrik Y.; Barton, Tom F. et al.
Object Type: Report
System: The UNT Digital Library
Advanced Imaging Catheter: Final Project Report (open access)

Advanced Imaging Catheter: Final Project Report

Minimally invasive surgery (MIS) is an approach whereby procedures conventionally performed with large and potentially traumatic incisions are replaced by several tiny incisions through which specialized instruments are inserted. Early MIS, often called laparoscopic surgery, used video cameras and laparoscopes to visualize and control the medical devices, which were typically cutting or stapling tools. More recently, catheter-based procedures have become a fast growing sector of all surgeries. In these procedures, small incisions are made into one of the main arteries (e.g. femoral artery in the thigh), and a long thin hollow tube is inserted and positioned near the target area. The key advantage of this technique is that recovery time can be reduced from months to a matter of days. In the United States, over 700,000 catheter procedures are performed annually representing a market of over $350 million. Further growth in this area will require significant improvements in the current catheter technology. In order to effectively navigate a catheter through the tortuous vessels of the body, two capabilities must exist: imaging and positioning. In most cases, catheter procedures rely on radiography for visualization and manual manipulation for positioning of the device. Radiography provides two-dimensional, global images of the vasculature and …
Date: July 20, 2001
Creator: Krulevitch, P.; Colston, B.; DaSilva, L.; Hilken, D.; Kluiwstra, J. U.; Lee, A. P. et al.
Object Type: Report
System: The UNT Digital Library
ADVANCED TECHNOLOGIES FOR STRIPPER GAS WELL ENHANCEMENT (open access)

ADVANCED TECHNOLOGIES FOR STRIPPER GAS WELL ENHANCEMENT

As part of Task 1 in Advanced Technologies for Stripper Gas Well Enhancement, Schlumberger--Holditch Reservoir Technologies (H-RT) has joined with two Appalachian Basin producers, Great Lakes Energy Partners, LLC, and Belden & Blake Corporation to develop methodologies for identification and enhancement of stripper wells with economic upside potential. These industry partners have provided us with data for more than 700 wells in northwestern Pennsylvania. Phase 1 goals of this project are to develop and validate methodologies that can quickly and cost-effectively identify wells with enhancement potential. We have continued to enhance and streamline our software, and we are testing the final stages of our new Microsoft{trademark} Access/Excel based software. We are continuing to process this well data and are identifying potential candidate wells that can be used in Phase 2 to validate the new methodologies. In addition, preparation of the final technical report is underway.
Date: July 1, 2001
Creator: Boyer, Charles M., II & MacDonald, Ronald J.
Object Type: Report
System: The UNT Digital Library
Advances in ANL reactor physics methods inspired by A. F. Henry. (open access)

Advances in ANL reactor physics methods inspired by A. F. Henry.

None
Date: July 6, 2001
Creator: Khalil, H. S.; Taiwo, T. A.; Yang, W. S. & Finck, P. J.
Object Type: Article
System: The UNT Digital Library
The Advocate, Volume 6, Issue 4, July-August 2001 (open access)

The Advocate, Volume 6, Issue 4, July-August 2001

Quarterly update providing information on environmental regulations for small businesses and local governments in Texas.
Date: July 2001
Creator: Texas Commission on Environmental Quality. Small Business and Environmental Assistance Division.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Alignment of the Fermilab D0 Detector (open access)

Alignment of the Fermilab D0 Detector

The Fermilab D0 detector was used for the discovery of the top quark during Run I in 1996. It is currently being upgraded to exploit the physics potential to be presented by the Main Injector and the Tevatron Collider during Run II in the Fall of 2000. Some of the essential elements of this upgrade is the upgrade of the Solenoid Magnet, the Central Fiber Tracker, the Preshower Detectors, the Calorimeter System, and the Muon System. This paper discusses the survey and alignment of the these detectors with emphasis on the Muon detector system. The alignment accuracy is specified as better than 0.5mm. A combination of the Laser Tracker, BETS, and V-STARS systems are used for the survey.
Date: July 20, 2001
Creator: Oshinowo, Babatunde O'Sheg
Object Type: Article
System: The UNT Digital Library
Alternative Motor Fuels and Vehicles: Impact on the Transportation Sector (open access)

Alternative Motor Fuels and Vehicles: Impact on the Transportation Sector

Testimony issued by the General Accounting Office with an abstract that begins "The transportation sector accounts for roughly two thirds of the nation's petroleum consumption and one quarter of the total U.S. energy use. Several steps have been taken during the last 25 years either to reduce petroleum consumption or to increase fuel diversity in the transportation sector, including tax incentives, mandates for alternative fuel vehicles, and laws to promote automobile fuel efficiency. This testimony discusses the extent of alternative fuel vehicle acquisition and fuel use, some of the barriers inhibiting greater use of alternative fuels and vehicles, and the federal tax incentives used to promote the use of alternative motor fuels and vehicles. So far, alternative fuels and vehicles have not made much of a dent in the conventional fuel and vehicle dominance of the U.S. vehicle fleet, primarily because of fundamental economic obstacles, such as the relatively low price of oil, insufficient availability of alternative fuel refueling infrastructure, and the relatively high cost of some alternative fuel vehicles. As GAO reported in February 2000 (RCED-00-59), any significant increase in the use of alternative motor fuels and vehicles by the general public will depend on the following two factors: …
Date: July 10, 2001
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Aluminum-Oxide Temperatures on the Mark VB, VE, VR, 15, and Mark 25 Assemblies (open access)

Aluminum-Oxide Temperatures on the Mark VB, VE, VR, 15, and Mark 25 Assemblies

The task was to compute the maximum aluminum-oxide and oxide-coolant temperatures of assemblies cladded in 99 plus percent aluminum. The assemblies considered were the Mark VB, VE, V5, 15 and 25. These assemblies consist of nested slug columns with individual uranium slugs cladded in aluminum cans. The CREDIT code was modified to calculate the oxide film thickness and the aluminum-oxide temperature at each axial increment. The information in this report will be used to evaluate the potential for cladding corrosion of the Mark 25 assembly.
Date: July 17, 2001
Creator: Aleman, S. E.
Object Type: Report
System: The UNT Digital Library
Aluminum-Oxide Temperatures on the Mark VB, VE, VR, 15, and Mark 25 Assemblies (open access)

Aluminum-Oxide Temperatures on the Mark VB, VE, VR, 15, and Mark 25 Assemblies

The task was to compute the maximum aluminum-oxide and oxide-coolant temperatures of assemblies cladded in 99+ percent aluminum. The assemblies considered were the Mark VB, VE, V5, 15 and 25. These assemblies consist of nested slug columns with individual uranium slugs cladded in aluminum cans. The CREDIT code was modified to calculate the oxide film thickness and the aluminum-oxide temperature at each axial increment. This information in this report will be used to evaluate the potential for cladding corrosion of the Mark 25 assembly.
Date: July 17, 2001
Creator: Aleman, S. E.
Object Type: Report
System: The UNT Digital Library
American Nuclear Society nuclear criticality safety division. (open access)

American Nuclear Society nuclear criticality safety division.

Development of an ANSI/ANS Standard for the training and qualification of criticality safety engineers has been underway for nearly one year. The working group for this Standard is comprised of criticality safety experts from regulatory, licensee and contractor organizations. Its goal is to develop a standard that can be uniformly adopted, that covers all criticality safety engineer qualification levels, and that includes all required competencies such that most of the qualifications can be easily transferred between sites. This status report is presented to let the general criticality safety community know of progress on the Standard, and to solicit feedback to the working group as it continues work on ANSI/ANS-8.26.
Date: July 26, 2001
Creator: Morman, J. A. & McKamy, J.
Object Type: Article
System: The UNT Digital Library
ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER (open access)

ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from …
Date: July 31, 2001
Creator: Gallagher, John R.
Object Type: Report
System: The UNT Digital Library
Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography (open access)

Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography

The Learning Objective is to present to the forensic community a potential qualitative/quantitative method for trace-fiber color comparisons using micellar electrokinetic chromatography (MEKC). Developing a means of analyzing extracted dye constituents from millimeter-size nylon fiber samples was the objective of this research initiative. Aside from ascertaining fiber type, color evaluation and source comparison of trace-fiber evidence plays a critical role in forensic-fiber examinations. Literally thousands of dyes exist to date, including both natural and synthetic compounds. Typically a three-color-dye combination is employed to affect a given color on fiber material. The result of this practice leads to a significant number of potential dye combinations capable of producing a similar color and shade. Since a typical forensic fiber sample is 2 mm or less in length, an ideal forensic dye analysis would qualitatively and quantitatively identify the extracted dye constituents from a sample size of 1 mm or smaller. The goal of this research was to develop an analytical method for comparing individual dye constituents from trace-fiber evidence with dyes extracted from a suspected source, while preserving as much of the original evidence as possible.
Date: July 30, 2001
Creator: Lewis, L. A.
Object Type: Article
System: The UNT Digital Library