Clean Cities Technical Assistance (Tiger Teams): Clean Cities Alternative Fuel Information Series, Technical Assistance Fact Sheet (open access)

Clean Cities Technical Assistance (Tiger Teams): Clean Cities Alternative Fuel Information Series, Technical Assistance Fact Sheet

A description of Tiger Teams, sponsored by DOE and NREL to help implement the use of alternative fuels by constituents of DOE's Clean Cities coalitions.
Date: March 5, 2001
Creator: Parish, R.
Object Type: Book
System: The UNT Digital Library
CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS FUELS (open access)

CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS FUELS

The following are proposed activities for quarter 2 (9/15/00-12/14/00): (1) Conduct TGA and fuel characterization studies--Task 1; (2) Perform re-burn experiments--Task 2; (3) Fabricate fixed bed gasifier/combustor--Task 3; and (4) Modify the 3D combustion modeling code for feedlot and litter fuels--Task 4. The following were achieved During Quarter 2 (9/15/00-12/14/00): (1) The chicken litter has been obtained from Sanderson farms in Denton, after being treated with a cyclonic dryer. The litter was then placed into steel barrels and shipped to California to be pulverized in preparation for firing. Litter samples have also been sent for ultimate/proximate laboratory analyses.--Task 1; (2) Reburn-experiments have been conducted on coal, as a base case for comparison to litter biomass. Results will be reported along with litter biomass as reburn fuel in the next report--Task 2; (3) Student has not yet been hired to perform task 3. Plans are ahead to hire him or her during quarter No. 3; and (4) Conducted a general mixture fraction model for possible incorporation in the code.
Date: February 5, 2001
Creator: Annamalai, Dr. Kalyan; Sweeten, Dr. John & Mukhtar, Dr. Sayeed
Object Type: Report
System: The UNT Digital Library
Computational Design Studies for an Ion Extraction System for a ''volume-type'' ECR Ion Source (open access)

Computational Design Studies for an Ion Extraction System for a ''volume-type'' ECR Ion Source

Numerical studies have been performed for optimally extracting high-intensity, space-charged-limited multi-charged ion beams from an all-permanent-magnet, ''volume-type'' ECR ion source, equipped with a three-electrode extraction system. These studies clearly demonstrate the importance of being able to adjust the extraction gap in order to ensure high quality, minimum divergence (highly transportable) ion beams. Optimum extraction conditions are reached whenever the plasma meniscus has an optimum curvature for a given current density. Optimum perveance (optimum current) values are found to closely agree with those derived from elementary analytical theory for extraction of space-charge-dominated beams. Details of the electrode system design as well as angular divergence and RMS emittance versus extraction parameter data (e.g., perveance and extraction gap) are provided for ion beams of varying charge-state and mass, extracted under the influence of a mirror-geometry plasma confinement magnetic field.
Date: November 5, 2001
Creator: Zaim, H.
Object Type: Article
System: The UNT Digital Library
CSEWG SYMPOSIUM, A CSWEG RETROSPECTIVE. 35TH ANNIVERSARY CROSS SECTION EVALUATION WORKING GROUP, NOV. 5, 2001, BROOKHAVEN NATIONAL LABORATORY. (open access)

CSEWG SYMPOSIUM, A CSWEG RETROSPECTIVE. 35TH ANNIVERSARY CROSS SECTION EVALUATION WORKING GROUP, NOV. 5, 2001, BROOKHAVEN NATIONAL LABORATORY.

This publication has been prepared to record some of the history of the Cross Section Evaluation Working Group (CSEWG). CSEWG is responsible for creating the evaluated nuclear data file (ENDF/B) which is widely used by scientists and engineers who are involved in the development and maintenance of applied nuclear technologies. This organization has become the model for the development of nuclear data libraries throughout the world. The data format (ENDF) has been adopted as the international standard. On November 5, 2001, a symposium was held at Brookhaven National Laboratory to celebrate the 50 th meeting of the CSEWG organization and the 35 th anniversary of its first meeting in November 1966. The papers presented in this volume were prepared by present and former CSEWG members for presentation at the November 2001 symposium. All but two of the presentations are included. I have included an appendix to list all of the CSEWG members and their affiliations, which has been compiled from the minutes of each of the CSEWG meetings. Minutes exist for all meetings except the 4 th meeting held in January 1968. The list includes 348 individuals from 71 organizations. The dates for each of the 50 CSEWG meetings are …
Date: November 5, 2001
Creator: DUNFORD, C.; HOLDEN, N. & PEARLSTEIN, S.
Object Type: Report
System: The UNT Digital Library
CSEWG SYMPOSIUM, A CSWEG RETROSPECTIVE. 35TH ANNIVERSARY CROSS SECTION EVALUATION WORKING GROUP, NOV. 5, 2001, BROOKHAVEN NATIONAL LABORATORY. (open access)

CSEWG SYMPOSIUM, A CSWEG RETROSPECTIVE. 35TH ANNIVERSARY CROSS SECTION EVALUATION WORKING GROUP, NOV. 5, 2001, BROOKHAVEN NATIONAL LABORATORY.

None
Date: November 5, 2001
Creator: Dunford, C.; Holden, N. & Pearlstein, S.
Object Type: Report
System: The UNT Digital Library
Decontamination and decommissioning activities photobriefing book FY 2000. (open access)

Decontamination and decommissioning activities photobriefing book FY 2000.

A major milestone was reached in Fiscal Year (FY) 2000--the completion of the Chicago Pile-5 (CP-5) D and D Project. CP-5, the first reactor built on the Argonne National Laboratory-East (ANL-E) site, was a 5-megawatt, heavy water-moderated, enriched uranium-fueled reactor. It was the principal reactor on the Argonne site used to produce neutrons for scientific research from 1954 to 1979. The reactor was shut down and defueled in 1979, and placed in a lay-up condition. In 1990, funding was provided to begin the decontamination and decommissioning (D and D) of this facility, and work began in June 1991. D and D tasks were performed by both ANL-E personnel and subcontractor personnel from Duke Engineering and Services, Marlborough MA, under the management of ANL-E D and D Program personnel. In July 2000, the final project report was presented to the Department of Energy, and the facility was formally decommissioned and transferred to the landlord. Total project duration was 97 months, and total project cost was $29.5M. Also, in FY 2000, work began on the 60 Cyclotron D and D Project. An accelerator used for basic research, this facility produced beams of deuterons, helium ions, singly charged hydrogen molecules, and neutrons of …
Date: February 5, 2001
Creator: Fellhauer, C. F.
Object Type: Report
System: The UNT Digital Library
Deformation At Crystallite Interfaces (open access)

Deformation At Crystallite Interfaces

Deformation at grain boundaries is observed and a framework for boundary specific constitutive laws based upon geometric considerations of slip transfer is developed. Orientation images of a pseudo-internal surface during interrupted channel die deformations of a Cu bi-crystal show the heterogeneity of lattice rotation near the grain boundary. The experiments demonstrate that a region near the boundary is strongly influenced by neighboring grain deformation and lend support to the development of deformation models that include the effects of non-local slip system interaction.
Date: October 5, 2001
Creator: Field, D P; Mortensen, A W; Nowell, M M & Campbell, G H
Object Type: Article
System: The UNT Digital Library
Depleted uranium hexafluoride management program : data compilation for the K-25 site. (open access)

Depleted uranium hexafluoride management program : data compilation for the K-25 site.

This report is a compilation of data and analyses for the K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The data were collected and the analyses were done in support of the U.S. Department of Energy (DOE) 1999 Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride (DOE/EIS-0269). The report describes the affected environment at the K-25 site and summarizes the potential environmental impacts that could result from continued cylinder storage and preparation of cylinders for shipment at the site. It is probable that the cylinders at the K-25 site will be shipped to another site for conversion. Because conversion and long-term storage of the entire inventory at the K-25 site are highly unlikely, these data are not presented in this report. DOE's preferred alternative is to begin converting the depleted uranium hexafluoride inventory as soon as possible to either uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible.
Date: June 5, 2001
Creator: Hartmann, H. M.
Object Type: Report
System: The UNT Digital Library
Depleted uranium hexafluoride management program : data compilation for the Portsmouth site. (open access)

Depleted uranium hexafluoride management program : data compilation for the Portsmouth site.

This report is a compilation of data and analyses for the Portsmouth site, near Portsmouth, Ohio. The data were collected and the analyses were done in support of the U.S. Department of Energy (DOE) 1999 Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride (DOE/EIS-0269). The report describes the affected environment at the Portsmouth site and summarizes potential environmental impacts that could result from conducting the following depleted uranium hexafluoride (UF{sub 6}) management activities at the site: continued cylinder storage, preparation of cylinders for shipment, conversion, and long-term storage. DOE's preferred alternative is to begin converting the depleted UF{sub 6} inventory as soon as possible to either uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible.
Date: June 5, 2001
Creator: Hartmann, H. M.
Object Type: Report
System: The UNT Digital Library
Deterrence and National Security in the Face of an Amorphous Threat (open access)

Deterrence and National Security in the Face of an Amorphous Threat

The National Security threats that we face today and, in turn, the National Security . requirements, are more diverse and complex than they were during the Cold-War from 1945-1990. During that period, and bolstered by the experiences of World Wars I and II, US National Security policy was focused on the stabilization of post WW II country boundaries and containment of the Soviet block and China. The result was the bipolar world in which the nuclear and conventional forces of the United States, the Soviet Union, and their respective allies ensured a measure of political stability through a military stalemate of world wide proportions. The practical result was that large scale changes in national borders were unlikely, but internal conflict within countries, and local conflicts between neighboring countries could still occur, albeit with participation from one or both of the Superpower camps. US National Security Policy was designed primarily for stabilization of the bipolar world on the military front and for competition with the Soviet Union and China on economic and political fronts. The collapse of the Soviet Union changed the global picture. The bipolar world and its military stalemate appear to be gone for the moment and the threat …
Date: January 5, 2001
Creator: Werne, R
Object Type: Report
System: The UNT Digital Library
Development of A Microwave Assisted Particulate Filter Regeneration System (open access)

Development of A Microwave Assisted Particulate Filter Regeneration System

The need for active regeneration of diesel particulate filters and the advantages of microwave assisted regeneration are discussed. The current study has multiple objectives, which include developing a microwave assisted particulate filter regeneration system for future generation light-duty diesel applications, including PNGV type applications. A variable power 2.0 kW microwave system and a tuned waveguide were employed. Cavity geometry is being optimized with the aid of computational modeling and temperature measurements during microwave heating. A wall-flow ceramic-fiber filter with superior thermal shock resistance, high filtration efficiency, and high soot capacity was used. The microwave assisted particulate filter regeneration system has operated for more than 100 hours in an engine test-cell with a 5.9-liter diesel engine with automated split exhaust flow and by-pass flow capabilities. Filter regeneration was demonstrated using soot loads up to 10 g/liter and engine exhaust at idling flow rates as the oxygen source. A parametric study to determine the optimal combination of soot loading, oxidant flow rate, microwave power and heating time is underway. Preliminary experimental results are reported.
Date: August 5, 2001
Creator: Popuri, Sriram
Object Type: Article
System: The UNT Digital Library
Development of a next-generation regional weather research and forecast model. (open access)

Development of a next-generation regional weather research and forecast model.

The Weather Research and Forecast (WRF) project is a multi-institutional effort to develop an advanced mesoscale forecast and data assimilation system that is accurate, efficient, and scalable across a range of scales and over a host of computer platforms. The first release, WRF 1.0, was November 30, 2000, with operational deployment targeted for the 2004-05 time frame. This paper provides an overview of the project and current status of the WRF development effort in the areas of numerics and physics, software and data architecture, and single-source parallelism and performance portability.
Date: February 5, 2001
Creator: Michalakes, J.; Chen, S.; Dudhia, J.; Hart, L.; Klemp, J.; Middlecoff, J. et al.
Object Type: Article
System: The UNT Digital Library
Development of a readout technique for the high data rate BTeV pixel detector at Fermilab (open access)

Development of a readout technique for the high data rate BTeV pixel detector at Fermilab

The pixel detector for the BTeV experiment at Fermilab provides digitized data from approximately 22 million silicon pixel channels. Portions of the detector are six millimeters from the beam providing a substantial hit rate and high radiation dose. The pixel detector data will be employed by the lowest level trigger system for track reconstruction every beam crossing. These requirements impose a considerable constraint on the readout scheme. This paper presents a readout technique that provides the bandwidth that is adequate for high hit rates, minimizes the number of radiation hard components, and satisfies all other design constraints.
Date: November 5, 2001
Creator: al., Bradley K Hall et
Object Type: Article
System: The UNT Digital Library
Development of Advanced Ceramic Manufacturing Technology (open access)

Development of Advanced Ceramic Manufacturing Technology

Advanced structural ceramics are enabling materials for new transportation engine systems that have the potential for significantly reducing energy consumption and pollution in automobiles and heavy vehicles. Ceramic component reliability and performance have been demonstrated in previous U.S. DOE initiatives, but high manufacturing cost was recognized as a major barrier to commercialization. Norton Advanced Ceramics (NAC), a division of Saint-Gobain Industrial Ceramics, Inc. (SGIC), was selected to perform a major Advanced Ceramics Manufacturing Technology (ACMT) Program. The overall objectives of NAC's program were to design, develop, and demonstrate advanced manufacturing technology for the production of ceramic exhaust valves for diesel engines. The specific objectives were (1) to reduce the manufacturing cost by an order of magnitude, (2) to develop and demonstrate process capability and reproducibility, and (3) to validate ceramic valve performance, durability, and reliability. The program was divided into four major tasks: Component Design and Specification, Component Manufacturing Technology Development, Inspection and Testing, and Process Demonstration. A high-power diesel engine valve for the DDC Series 149 engine was chosen as the demonstration part for this program. This was determined to be an ideal component type to demonstrate cost-effective process enhancements, the beneficial impact of advanced ceramics on transportation systems, …
Date: April 5, 2001
Creator: Pujari, V. K.
Object Type: Report
System: The UNT Digital Library
Development of Components for Wavelength Division Multiplexing Over Parallel Optical Interconnects (open access)

Development of Components for Wavelength Division Multiplexing Over Parallel Optical Interconnects

Parallel optical interconnects based on multimode fiber ribbon cables are emerging as a robust, high-performance data link technology that enhances throughput by using parallel arrays of fibers. While this technology has primarily been implemented as single wavelength point-to-point links, it can be significantly enhanced by wavelength division multiplexing (WDM). WDM enables both increased point-to-point bandwidth as well as more complex interconnect topologies and routing approaches that are particularly attractive for massively parallel processing (MPP) systems. Exploiting the advantages of WDM interconnects requires multi-wavelength sources, a low loss routing fabric, and small footprint wavelength selective filter modules. The Lambda-connect project ({gamma}- Connect) at Lawrence Livermore National Laboratory is a technology development and proof-of-principle demonstration of the enabling hardware for WDM parallel optical interconnects for use in massively parallel processing systems and other high-performance data link applications. This dissertation demonstrates several key system components and technologies for {gamma}-Connect.
Date: July 5, 2001
Creator: Patel, R
Object Type: Report
System: The UNT Digital Library
Development of laser-based resonance ionization techniques for 81-Kr and 85-Kr measurements in the geosciences, II. December 1, 1994 through December 31, 2000 reporting period. Final technical report for Grant No. DE-FG05-95ER14497 (open access)

Development of laser-based resonance ionization techniques for 81-Kr and 85-Kr measurements in the geosciences, II. December 1, 1994 through December 31, 2000 reporting period. Final technical report for Grant No. DE-FG05-95ER14497

A facility for measurement of rare Kr-81 and Kr-85 isotope concentration in hydrogeologic samples, and isotopic composition of minute quantities of krypton and xenon from extraterrestrial samples, was established, requiring refinement of an emerging mass spectrometric-based analytical technique and securing of laboratory space and equipment. The analytical process consists of (1) collecting a groundwater sample, (2) degassing the water, (3) separating Kr from the recovered gases, (4&5) two isotopic enrichments to reduce interfering isotopes by E9, and (6) detecting the rare krypton isotope in a unique time-of-flight mass spectrometer detecting as few as 100 Kr atoms. All equipment is installed and operating, with only some additional adjustment and testing of the last step (6, above) remaining to be completed. Collaborations have been established with a number of researchers and organizations world wide, and both groundwater and extraterrestrial samples have been collected. Completion of analyses awaits full operation of step 6.
Date: February 5, 2001
Creator: Thonnard, Norbert; McKay, Larry D. & Labotka, Theodore C.
Object Type: Report
System: The UNT Digital Library
Development of simulation tools for virus shell assembly. Final report (open access)

Development of simulation tools for virus shell assembly. Final report

Prof. Berger's major areas of research have been in applying computational and mathematical techniques to problems in biology, and more specifically to problems in protein folding and genomics. Significant progress has been made in the following areas relating to virus shell assembly: development has been progressing on a second-generation self-assembly simulator which provides a more versatile and physically realistic model of assembly; simulations are being developed and applied to a variety of problems in virus assembly; and collaborative efforts have continued with experimental biologists to verify and inspire the local rules theory and the simulator. The group has also worked on applications of the techniques developed here to other self-assembling structures in the material and biological sciences. Some of this work has been conducted in conjunction with Dr. Sorin Istrail when he was at Sandia National Labs.
Date: January 5, 2001
Creator: Berger, Bonnie
Object Type: Report
System: The UNT Digital Library
Diesel Engine Waste Heat Recovery Utilizing Electric Turbocompound Technology (open access)

Diesel Engine Waste Heat Recovery Utilizing Electric Turbocompound Technology

This cooperative program between the DOE Office of Heavy Vehicle Technology and Caterpillar, Inc. is aimed at demonstrating electric turbocompound technology on a Class 8 truck engine. This is a lab demonstration program, with no provision for on-truck testing of the system. The goal is to demonstrate the level of fuel efficiency improvement attainable with the electric turbocompound system. Also, electric turbocompounding adds an additional level of control to the air supply which could be a component in an emissions control strategy.
Date: August 5, 2001
Creator: Gerke, Frank G.
Object Type: Article
System: The UNT Digital Library
Direct Measurement of CO2 Fluxes in Marine Whitings (open access)

Direct Measurement of CO2 Fluxes in Marine Whitings

Clean, affordable energy is a requisite for the United States in the 21st Century Scientists continue to debate over whether increases in CO{sub 2} emissions to the atmosphere from anthropogenic sources, including electricity generation, transportation and building systems may be altering the Earth's climate. While global climate change continues to be debated, it is likely that significant cuts in net CO{sub 2} emissions will be mandated over the next 50-100 years. To this end, a number of viable means of CO{sub 2} sequestration need to be identified and implemented. One potential mechanism for CO{sub 2} sequestration is the use of naturally-occurring biological processes. Biosequestration of CO{sub 2} remains one of the most poorly understood processes, yet environmentally safe means for trapping and storing CO{sub 2}. Our investigation focused on the biogeochemical cycling of carbon in microbial precipitations of CaCO{sub 3}. Specifically, we investigated modern whitings (microbially-induced precipitates of the stable mineral calcium carbonate) as a potential, natural mechanism for CO{sub 2} abatement. This process is driven by photosynthetic metabolism of cyanobacteria and microalgae. We analyzed net air: sea CO{sub 2} fluxes, net calcification and photosynthetic rates in whitings. Both field and laboratory investigations have demonstrated that atmospheric CO{sub 2}decreases during …
Date: July 5, 2001
Creator: Robbins, Lisa L. & Yates, Kimberly K.
Object Type: Report
System: The UNT Digital Library
Drift-Scale Coupled Processes (DST and THC Seepage) Models (open access)

Drift-Scale Coupled Processes (DST and THC Seepage) Models

The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) 2000 [153447]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M and O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC seepage models. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal loading conditions, and predict the chemistry of waters and gases entering potential waste-emplacement drifts. The intended use of this AMR is to provide input for the following: (1) Performance Assessment (PA); (2) Abstraction of Drift-Scale Coupled Processes AMR (ANL-NBS-HS-000029); (3) UZ Flow and Transport Process Model Report (PMR); and (4) Near-Field Environment (NFE) PMR. The work scope for this activity is presented in the TWPs cited above, and summarized as follows: continue …
Date: February 5, 2001
Creator: Gonnenthal, E. & Spyoher, N.
Object Type: Report
System: The UNT Digital Library
Economical Recovery of By-products in the Mining Industry (open access)

Economical Recovery of By-products in the Mining Industry

The U.S. Department of Energy (DOE) Office of Industrial Technologies, Mining Industry of the Future Program, works with the mining industry to further the industry's advances toward environmental and economic goals. Two of these goals are (1) responsible emission and by-product management and (2) low-cost and efficient production (DOE 1998). DOE formed an alliance with the National Mining Association (NMA) to strengthen the basis for research projects conducted to benefit the mining industry. NMA and industry representatives actively participate in this alliance by evaluating project proposals and by recommending research project selection to DOE. Similarly, the National Research Council (NRC) has recently and independently recommended research and technology development opportunities in the mining industry (NRC 2001). The Oak Ridge National Laboratory (ORNL) and Colorado School of Mines engineers conducted one such project for DOE regarding by -product recovery from mining process residue. The results of this project include this report on mining industry process residue and waste with opportunity for by-product recovery. The U.S. mineral processing industry produces over 30,000,000 metric tons per year of process residue and waste that may contain hazardous species as well as valuable by-products. This study evaluates the copper, lead, and zinc commodity sectors which …
Date: December 5, 2001
Creator: Berry, J.B.
Object Type: Report
System: The UNT Digital Library
Effects of 2D and Finite Density Fluctuations on O-X Correlation Reflectometry (open access)

Effects of 2D and Finite Density Fluctuations on O-X Correlation Reflectometry

The correlation between O-mode and X-mode reflectometer signals is studied with a 1D and 2D reflectometer model in order to explore its feasibilities as a q-profile diagnostic. It was found that 2D effects and finite fluctuation levels both decrease the O-X correlation. At very low fluctuation levels, which are usually present in the plasma core, there is good possibility to determine the local magnetic field strength and use that as a constraint for the equilibrium reconstruction.
Date: July 5, 2001
Creator: Kramer, G. J.; Nazikian, R. & Valeo, E.
Object Type: Report
System: The UNT Digital Library
THE EFFECTS OF BIODIESEL BLENDS AND ARCO EC-DIESEL ON EMISSIONS from LIGHT HEAVY-DUTY DIESEL VEHICLES (open access)

THE EFFECTS OF BIODIESEL BLENDS AND ARCO EC-DIESEL ON EMISSIONS from LIGHT HEAVY-DUTY DIESEL VEHICLES

Chassis dynamometer tests were performed on 7 light heavy-duty diesel trucks comparing the emissions of a California diesel fuel with emissions from 4 other fuels: ARCO EC-diesel (EC-D) and three 20% biodiesel blends (1 yellow grease and 2 soy-based). The EC-D and the yellow grease biodiesel blend both showed significant reductions in THC and CO emissions over the test vehicle fleet. EC-D also showed reductions in PM emission rates. NOx emissions were comparable for the different fuel types over the range of vehicles tested. The soy-based biodiesel blends did not show significant or consistent emissions differences over all test vehicles. Total carbon accounted for more than 70% of the PM mass for 4 of the 5 sampled vehicles. Elemental and organic carbon ratios varied significantly from vehicle-to-vehicle but showed very little fuel dependence. Inorganic species represented a smaller portion of the composite total, ranging from 0.2 to 3.3% of the total PM. Total PAH emissions ranged from approximately 1.8 mg/mi to 67.8 mg/mi over the different vehicle/fuel combinations representing between 1.6 and 3.8% of the total PM mass.
Date: August 5, 2001
Creator: Durbin, Thomas
Object Type: Article
System: The UNT Digital Library
Effusive-flow characterization of arbitrary size and geometry target/vapor transport systems: radioactive ion beam applications (open access)

Effusive-flow characterization of arbitrary size and geometry target/vapor transport systems: radioactive ion beam applications

The principal factors that severely limit intensities of short-lived radioactive ion beams produced by the Isotope Separator On-Line (ISOL) technique are time delays due to diffusion of radioactive species from solid or liquid target materials and their effusive-flow transport to the ion source. Although diffusion times can be reduced by proper design of short diffusion length, highly refractory targets, effusive-flow times are more difficult to assess. After diffusion from the target material, the species must travel through the target material and vapor transport system to the ion source. The time required for effusive-flow transport to the ion source depends on the conduction path, chemical reactions between the species and target material and materials of construction as well as the physical size and geometry of the transport system. We have developed a fast-valve (1 ms closing time) for introducing gaseous or vapor-state species into the target/vapor transport/ion source/system th at permits measurement of effusive-flow times for any gaseous or vaporous species (chemically active or chemically inactive) through any vapor transport system, independent of size and geometry. Characteristic times are determined from the exponential decay of the momentum analyzed ion beam intensity for the species.during effusive-flow through the vapor transport system under …
Date: November 5, 2001
Creator: Bilheux, J.-C.
Object Type: Article
System: The UNT Digital Library