Rapidity and centrality dependence of proton and anti-proton production from 197Au+197Au collisions at {radical}(s{sub NN}) = 130 GeV (open access)

Rapidity and centrality dependence of proton and anti-proton production from 197Au+197Au collisions at {radical}(s{sub NN}) = 130 GeV

We report on the rapidity and centrality dependence of proton and anti-proton transverse mass distributions from {sup 197}Au + {sup 197}Au collisions at {radical}s{sub NN} = 130 GeV as measured by the STAR experiment at RHIC. Our results are from the rapidity and transverse momentum range of |y| < 0.5 and 0.35 < p{sub t} < 1.00 GeV/c. For both protons and anti-protons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within |y| < 0.5. Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton(anti-proton) yields and transverse mass distributions the possibility of pre-hadronic collective expansion may have to be taken into account.
Date: June 20, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type: Article
System: The UNT Digital Library
Extraction of macro-molecule images in cryo-EM micrographs (open access)

Extraction of macro-molecule images in cryo-EM micrographs

Advances in Electron Microscopy and single-particle reconstruction have led to results at increasingly high resolutions. This has opened up the possibility of complete automation of single particle reconstruction. Main bottleneck in automation of single particle reconstruction is manual selection of particles in the micrograph. This paper describes a simple but efficient approach for segmentation of particle projections in the micrographs obtained using cryo-electron microscope. Changing the shape of objects to facilitate segmentation from the cluster and reconstructing its actual shape after isolation is successfully attempted. Both low-level and high-level processing techniques are used and the whole process is made automatic. Over 90 percent success in automatic particle picking is achieved. Several areas for improvement and future research directions are discussed.
Date: March 20, 2003
Creator: Adiga, Umesha P.S.; Malladi, Ravi & Glaeser, Robert M.
Object Type: Report
System: The UNT Digital Library
Performing Neutron Cross-Section Measurements at RIA (open access)

Performing Neutron Cross-Section Measurements at RIA

The Rare Isotope Accelerator (RIA) is a proposed accelerator for the low energy nuclear physics community. Its goal is to understand the natural abundances of the elements heavier than iron, explore the nuclear force in systems far from stability, and study symmetry violation and fundamental physics in nuclei. To achieve these scientific goals, RIA promises to produce isotopes far from stability in sufficient quantities to allow experiments. It would also produce near stability isotopes at never before seen production rates, as much as 10{sup 12} pps. Included in these isotopes are many that are important to stockpile stewardship, such as {sup 87}Y, {sup 146-50}Eu, and {sup 231}Th. Given the expected production rates at RIA and a reasonably intense neutron source, one can expect to make {approx} 10 {micro}g targets of nuclei with a half-life of {approx}1 day. Thus, it will be possible at RIA to obtain experimental information on the neutron cross section for isotopes that have to date only been determined by theory. There are two methods to perform neutron cross-section measurements, prompt and delayed. The prompt method tries to measure each reaction as it happens. The exact technique employed will depend on the reaction of interest, (n,2n), (n,{gamma}), …
Date: May 20, 2003
Creator: Ahle, L. E.
Object Type: Report
System: The UNT Digital Library
A Neutron Source Facility for Neutron Cross-Section Measurements on Radioactive Targets at RIA (open access)

A Neutron Source Facility for Neutron Cross-Section Measurements on Radioactive Targets at RIA

The stockpile stewardship program is interested in neutron cross-section measurements on nuclei that are a few nucleons away from stability. Since neutron targets do not exist, radioactive targets are the only way to directly perform these measurements. This requires a facility that can provide high production rates for these short-lived nuclei as well as a source of neutrons. The Rare Isotope Accelerator (RIA) promises theses high production rates. Thus, adding a co-located neutron source facility to the RIA project baseline would allow these neutron cross-section measurements to be made. A conceptual design for such a neutron source has been developed, which would use two accelerators, a Dynamitron and a linac, to create the neutrons through a variety of reactions (d-d, d-t, deuteron break-up, p-Li). This range of reactions is needed in order to provide the desired energy range from 10's of keV to 20 MeV. The facility would also have hot cells to perform chemistry on the radioactive material both before and after neutron irradiation. The present status of this design and direction of future work will be discussed.
Date: May 20, 2003
Creator: Ahle, L. E.; Bernstein, L.; Rusnak, B. & Berio, R.
Object Type: Article
System: The UNT Digital Library
Preliminary Authorization Basis Documentation for the Proposed Bio Safety Level 3 (BSl-3) Facility (open access)

Preliminary Authorization Basis Documentation for the Proposed Bio Safety Level 3 (BSl-3) Facility

Lawrence Livermore National Laboratory (LLNL) is proposing to construct a biosafety level (BSL-3) facility at Site 200 in Livermore, California. Biosafety level 3 (BSL-3) is a designation assigned by the Centers for Disease Control and Prevention (CDC) and National Institutes Health (NIH) for handling infectious organisms based on the specific microorganisms and associated operations. Biosafety levels range from BSL-1 (lowest hazard) to BSL-4 (highest hazard). Details about the BSL-3 criteria are described in the Center of Disease Control and Prevention (CDC)/National Institutes of Health (NIH)'s publication ''Biosafety Microbiological and Biomedical Laboratories'' (BMBL), 4th edition (CDC 1999): The BSL-3 facility will be built in accordance with the required BMBL guidelines. This Preliminary Authorization Basis Documentation (PABD) for the proposed BSL-3 facility has been prepared in accordance with the current contractual requirements at LLNL. This includes the LLNL Environment, Safety, and Health Manual (ES&H Manual) and applicable Work Smart Standards, including the biosafety standards, such as the aforementioned BMBL and the NIH Guidelines for Research Involving Recombinant DNA Molecules: The proposed BSL-3 facility is a 1,100 ft{sup 2}, one-story permanent prefabricated facility, which will have three individual BSL-3 laboratory rooms (one of which is an animal biosafety level-3 [ABSL-3] laboratory to handle …
Date: September 20, 2003
Creator: Altenbach, T J & Nguyen, S N
Object Type: Report
System: The UNT Digital Library
Research Administration Benchmarking Project (open access)

Research Administration Benchmarking Project

The National Science Foundation (NSF) is conducting a collection of baseline data that will serve as an index for describing the way in which grant applications/proposals are developed and tracked at grant recipient organizations. The type of information to be collected includes (1) estimate of burden, both time and cost, to the applicant organization (2) descriptiion of the overall development and tracking systems used by the applicant, and (3) data that can be compared after the implementation of either a streamlined paper or electronic system.
Date: April 20, 2003
Creator: Arnest, Paul
Object Type: Report
System: The UNT Digital Library
Eliminating a Major Cause of Wire Drawing Breakage in A-15 High-Field Superconductors (open access)

Eliminating a Major Cause of Wire Drawing Breakage in A-15 High-Field Superconductors

Eliminating a Major Cause of Wire Drawing Breakage in A-15 High-Field Superconductors Phase 1 Summary Purpose of the research: The Phase 1 goal was to make a significant improvement in the wire drawing technology used for difficult to draw superconductor precursor composites. Many ductile Nb-Al and Nb-Sn precursor wire composites have experienced the onset of wire drawing breakage at about 1.5 mm diameter. Phase 1 focused on evaluating the role that precision rigid guidance of the wire into the drawing die and the hydrostatic stress state at the die entrance played in preventing wire breakage. Research carried out: The research performed depended upon the construction of both a mechanical wire guide and a hydrostatic pressure stiffened wire guidance system. Innovare constructed the two wire guidance systems and tested them for their ability to reduce wire drawing breakage. One set of hardware provided rigid alignment of the wires to their wire drawing die axes within 0.35 degrees using ''hydrostatic pressure stiffening'' to enable the precision guidance strategy to be implemented for these highly flexible small diameter wires. This apparatus was compared to a guide arrangement that used short span mechanical guide alignment with a misalignment limit of about 0.75 degrees. Four …
Date: May 20, 2003
Creator: Austen, Alfred R.
Object Type: Report
System: The UNT Digital Library
Fabrication of large diameter alumino-silicate K{sup +} sources (open access)

Fabrication of large diameter alumino-silicate K{sup +} sources

Alumino-silicate K{sup +} sources have been used in HIF experiments for many years. For example the Neutralized Transport Expt. (NTX) and the High Current Transport Expt. (HCX) are now using this type of ion source with diameters of 2.54 cm and 10 cm respectively. These sources have demonstrated ion currents of 80 mA and 700 mA, for typical HIF pulse lengths of 5-10 {micro}s. The corresponding current density is {approx} 10-15 mA/cm{sup 2}, but much higher current density has been observed using smaller size sources. Recently we have improved our fabrication techniques and, therefore, are able to reliably produce large diameter ion sources with high quality emitter surface without defects. This note provides a detailed description of the procedures employed in the fabrication process. The variables in the processing steps affecting surface quality, such as substrate porosity, powder size distribution, coating technique on large area concave surfaces, drying, and heat firing temperature have been investigated.
Date: February 20, 2003
Creator: Baca, D.; Chacon-Golcher, E.; Kwan, J. W. & Wu, J. K.
Object Type: Article
System: The UNT Digital Library
Performance Technolgies for Peta-Scale Systems: A White Paper Prepared by the Performance Evaluation Research Center (open access)

Performance Technolgies for Peta-Scale Systems: A White Paper Prepared by the Performance Evaluation Research Center

Future-looking high end computing initiatives will deploy powerful, large-scale computing platforms that leverage novel component technologies for superior node performance in advanced system architectures with tens or even hundreds of thousands of nodes. Recent advances in performance tools and modeling methodologies suggest that it is feasible to acquire such systems intelligently and achieve excellent performance, while also significantly reducing the user time required to attain high performance. These developments are relevant to several aspects of future HEC technology outlined in the recent HECRTF white paper request, in particular items 5.4, 5.5, 5.6, and 5.8. We envision the following specific capabilities: (1) Performance modeling tools, available to researchers and vendors, will extrapolate performance from prototype systems to full-scale systems, and even accurately predict performance behavior before systems are manufactured, thus enabling both improved designs and more intelligent selection of systems in procurements. (2) System simulation facilities, implemented on highly parallel platforms and available to researchers and vendors, will for instance realistically model the performance of a specific interprocessor network design running a specific scientific application code. As with item 1, these facilities can lead both to improved designs and procurement decisions that yield significantly greater sustained performance for targeted scientific applications. …
Date: May 20, 2003
Creator: Bailey, D. H.; de Supinski, B. R.; Dongarra, J.; Dunigan, T.; Gao, G.; Hoisie, A. et al.
Object Type: Report
System: The UNT Digital Library
Thermodynamic Modeling of the AWE Radioactive Aqueous Waste Treatment Plant Evaporator (open access)

Thermodynamic Modeling of the AWE Radioactive Aqueous Waste Treatment Plant Evaporator

Operation of the proposed AWE Aldermaston1 Radioactive Aqueous Waste Treatment Plant evaporation system was modeled using the Environmental Simulation Program (ESP) licensed by OLI Systems, Inc. The projected RAWTP waste influents as well as two simulants (High Foam and Low Foam) were modeled to predict the composition of the feed, concentrate and condensate for projected waste influents. This report details the results of the modeled predictions.
Date: October 20, 2003
Creator: Barnes, C.D.
Object Type: Report
System: The UNT Digital Library
A method for repairing amplitude defects in multilayer-coated EUV mask blanks (open access)

A method for repairing amplitude defects in multilayer-coated EUV mask blanks

EUV mask blanks are fabricated by depositing a reflective Mo/Si multilayer film onto super-polished substrates. Localized defects in this thin film coating can significantly perturb the reflected field and produce errors in the printed image. Ideally one would want to manufacture defect-free mask blanks; however, this may be very difficult to achieve in practice. One practical way to increase the yield of mask blanks is to be able to repair a significant number of the defects in the multilayer coating. In this paper we present a method for repairing defects that are near the top surface of the coating; we call these amplitude defects because they predominantly attenuate the amplitude of the reflected field. Although the discussion is targeted to the application of manufacturing masks for EUV lithography, the conclusions and results are also applicable to understanding the optical effects of multilayer erosion, including ion-induced multilayer erosion and condenser erosion in EUVL steppers.
Date: October 20, 2003
Creator: Barty, A.; Hau-Riege, S.; Stearns, D.; Clift, M.; Mirkarimi, P.; Gullikson, E. et al.
Object Type: Article
System: The UNT Digital Library
Autonomous Control of Nuclear Power Plants (open access)

Autonomous Control of Nuclear Power Plants

A nuclear reactor is a complex system that requires highly sophisticated controllers to ensure that desired performance and safety can be achieved and maintained during its operations. Higher-demanding operational requirements such as reliability, lower environmental impacts, and improved performance under adverse conditions in nuclear power plants, coupled with the complexity and uncertainty of the models, necessitate the use of an increased level of autonomy in the control methods. In the opinion of many researchers, the tasks involved during nuclear reactor design and operation (e.g., design optimization, transient diagnosis, and core reload optimization) involve important human cognition and decisions that may be more easily achieved with intelligent methods such as expert systems, fuzzy logic, neural networks, and genetic algorithms. Many experts in the field of control systems share the idea that a higher degree of autonomy in control of complex systems such as nuclear plants is more easily achievable through the integration of conventional control systems and the intelligent components. Researchers have investigated the feasibility of the integration of fuzzy logic, neural networks, genetic algorithms, and expert systems with the conventional control methods to achieve higher degrees of autonomy in different aspects of reactor operations such as reactor startup, shutdown in …
Date: October 20, 2003
Creator: Basher, H.
Object Type: Report
System: The UNT Digital Library
Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs (open access)

Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

The ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' (Grant/Cooperative Agreement DE-FC26-02NT15342) began September 1, 2002. During this second quarter: A Direct Hydrocarbon Indicator (DHI) symposium was held at UH; Current DHI methods were presented and forecasts made on future techniques; Dr. Han moved his laboratory from HARC to the University of Houston; Subcontracts were re-initiated with UH and TAMU; Theoretical and numerical modeling work began at TAMU; Geophysical Development Corp. agreed to provide petrophysical data; Negotiations were begun with Veritas GDC to obtain limited seismic data; Software licensing and training schedules were arranged with Paradigm; and Data selection and acquisition continues. The broad industry symposium on Direct Hydrocarbon Indicators was held at the University of Houston as part of this project. This meeting was well attended and well received. A large amount of information was presented, not only on application of the current state of the art, but also on expected future trends. Although acquisition of appropriate seismic data was expected to be a significant problem, progress has been made. A 3-D seismic data set from the shelf has been installed at Texas A&M University and analysis begun. Veritas GDC has expressed a willingness to provide data in the …
Date: March 20, 2003
Creator: Batzle, M.; Han, D-h; Gibson, R. & Djordjevic, O.
Object Type: Report
System: The UNT Digital Library
Laboratory Wavelengths of K-Shell Resonance Lines of O V and O VI (open access)

Laboratory Wavelengths of K-Shell Resonance Lines of O V and O VI

We present wavelength measurements of K-shell resonance lines of O V and O VI, using the University of California Lawrence Livermore National Laboratory EBIT-I electron beam ion trap. The wavelength accuracy of better than 140 ppm is sufficient to determine gas outflow velocities of warm absorbers associated with AGNs to within 40 km/s and better. Our measurements confirm that the outflow velocities associated with NGC 5548 and derived from O V and O VI lines are similar to those derived from the O VII lines. These kinematic measurements make for further evidence that the X-ray and UV absorbers in these systems are truly two manifestations of the same physical outflow.
Date: November 20, 2003
Creator: Beiersdorfer, Peter; Chen, Hui; Schmidt, Mike; Behar, Ehud; Trabert, Elmar & Thorn, Daniel B.
Object Type: Article
System: The UNT Digital Library
Adaptive low Mach number simulations of nuclear flame microphysics (open access)

Adaptive low Mach number simulations of nuclear flame microphysics

We introduce a numerical model for the simulation of nuclear flames in Type Ia supernovae. This model is based on a low Mach number formulation that analytically removes acoustic wave propagation while retaining the compressibility effects resulting from nuclear burning. The formulation presented here generalizes low Mach number models used in combustion that are based on an ideal gas approximation to the arbitrary equations of state such as those describing the degenerate matter found in stellar material. The low Mach number formulation permits time steps that are controlled by the advective time scales resulting in a substantial improvement in computational efficiency compared to a compressible formulation. We briefly discuss the basic discretization methodology for the low Mach number equations and their implementation in an adaptive projection framework. We present validation computations in which the computational results from the low Mach number model are compared to a compressible code and present an application of the methodology to the Landau-Darrieus instability of a carbon flame.
Date: March 20, 2003
Creator: Bell, J. B.; Day, M. S.; Rendleman, C. A.; Woosley, S. E. & Zingale, M. A.
Object Type: Article
System: The UNT Digital Library
Validating the Predicted Lateral Straggling of MeV-Energy Proton Beams (open access)

Validating the Predicted Lateral Straggling of MeV-Energy Proton Beams

Proton imaging is a potential nondestructive method for characterizing NIF (National Ignition Facility) targets in two- and three-dimensions with micron-scale spatial resolution. The main limitation for high resolution imaging with proton beams, especially for thick samples, is the positional blurring of the proton beam, known as ''lateral straggling''. Accurate prediction of the amount of lateral straggling and, consequently, the achievable spatial resolution in pertinent NIF target material combinations and geometries requires validated proton transport models. We present results of Monte Carlo simulations of MeV-energy proton transport through thin ({approx}1 micron thick) metal foils. The calculated residual proton distributions are compared to recent lateral straggling measurements obtained at the LLNL 4-MV Pelletron accelerator.
Date: November 20, 2003
Creator: Bench, G.; Felter, T. & Antolak, A.
Object Type: Report
System: The UNT Digital Library
Tissue architecture: the ultimate regulator of breast epithelial function (open access)

Tissue architecture: the ultimate regulator of breast epithelial function

A problem in developmental biology that continues to take center stage is how higher organisms generate diverse tissues and organs given the same cellular genotype. In cell and tumor biology, the key question is not the production of form, but its preservation: how do tissues and organs maintain homeostasis, and how do cells within tissues lose or overcome these controls in cancer? Undoubtedly, mechanisms that maintain tissue specificity should share features with those employed to drive formation of the tissues. However, they are unlikely to be identical. At a simplistic level, developmental pathways may be thought of as a series of extremely rapid short-term events. Each new step depends on what came before, and the outcome is the organism itself at birth. All organs, with a few notable exceptions, such as the mammary gland and the brain, 'arrive' together and are complete when the organism is born. In mice and humans, these events occur in a mere 21 days and 9 months respectively. The stability of the differentiated state and the homeostasis of the organism, on the other hand, will last 40-110 times longer. How does the organism achieve this feat? How are tissues maintained? These questions also relate fundamentally …
Date: October 20, 2003
Creator: Bissell, Mina J; Rizki, Aylin & Mian, Saira
Object Type: Article
System: The UNT Digital Library
Transient Scuffing of Candidate Diesel Engine Materials at Temperatures up to 600<sup>o</sup>C (open access)

Transient Scuffing of Candidate Diesel Engine Materials at Temperatures up to 600<sup>o</sup>C

This milestone report summarizes the general characteristics of scuffing damage to solid surfaces, then describes transient effects on scuffing observed during oscillating sliding wear tests of candidate material pairs for high-temperature diesel engine applications, like waste-gate bushings in exhaust gas recirculation (EGR) systems. It is shown that oxidation and the formation of wear particle layers influence the friction of such components. In the case of metallic materials in cylindrical contacts where there is a generous clearance, debris layers can form which reduce the torque over time. For ceramic combinations, the opposite effect is observed. Here, the accumulation of wear debris leads to an increase in the turning torque. High-temperature transient scuffing behavior is considered in terms of a series of stages in which the composition and morphology of the contact is changing. These changes are used to explain the behavior of 11 material pairs consisting of stainless steels, Ni-based alloys, Co-based alloys, and structural ceramics.
Date: June 20, 2003
Creator: Blau, P.
Object Type: Report
System: The UNT Digital Library
Centrales au gaz et Energies renouvelables: comparer des pommes avec des pommes (open access)

Centrales au gaz et Energies renouvelables: comparer des pommes avec des pommes

The fundamental conclusion that we draw from this analysis is that one should not to base itself blindly on forecasts prices of natural gas when one compare contracts at price fixes with producers of renewable energy with contracts at variable prices with promoters power stations with gas. Indeed, forecasts of the prices of gas do not succeed not to enter the associated costs with the covering of the risk, that they are connected to the negative pressure against the cover, with the CAPM, with costs of transaction or with unspecified combination of three. Thus, insofar as price stability to length term is developed, better way of comparing the two choices would be to have recourse to the data on the prices in the long term natural gas, and not with forecasts of the prices. During three last years at least, the use of these prices in the long term would have besides license to correct a methodological error who, obviously, seem to have supported unduly, and of relatively important way, power stations with natural gas compared to their competitors of renewable energies.
Date: October 20, 2003
Creator: Bolinger, Mark; Wiser, Ryan & Golove, William
Object Type: Report
System: The UNT Digital Library
NERI Final Project Report: On-Line Intelligent Self-Diagnostic Monitoring System for Next Generation Nuclear Power Plants (open access)

NERI Final Project Report: On-Line Intelligent Self-Diagnostic Monitoring System for Next Generation Nuclear Power Plants

This project provides a proof-of-principle technology demonstration for SDMS, where a distributed suite of sensors is integrated with active components and passive structures of types expected to be encountered in next generation nuclear power reactor and plant systems. The project employs state-of-the-art operational sensors, advanced stressor-based instrumentation, distributed computing, RF data network modules and signal processing to improve the monitoring and assessment of the power reactor system and gives data that is used to provide prognostics capabilities.
Date: June 20, 2003
Creator: Bond, Leonard J.; Jarrell, Donald B.; Koehler, Theresa M.; Meador, Richard J.; Sisk, Daniel R.; Hatley, Darrel D. et al.
Object Type: Report
System: The UNT Digital Library
Time-Domain Tools for the Investigation of Gain-Quenched Laser Logic (open access)

Time-Domain Tools for the Investigation of Gain-Quenched Laser Logic

Integrated all-optical logic gates that exploit the optical gain quenching effect in laterally optically pumped semiconductor multi-section edge-emitting lasers (SMEELs) are described. An accurate 2D time-domain (TD) model was implemented to investigate the gates' gain, modulation depth, and speed. Gain Quenched Laser Logic (GQLL) offer the potential of integrating several processing functions on the same chip and has many applications for all-optical high-speed switching. Lasers with optical gain control capable of routing and logic functions have been demonstrated via the gain quenching effect. In an inverter gate the laser output power is quenched when an optical input signal laterally coupled to the laser (control region) is high. NOR and NAND gates are achievable by adding other arms. The basic configuration of a GQLL device is schematically depicted in Fig. 1 . The Boolean completeness of this technology, the recent achievement in high laser modulation bandwidths, and the possibility of integrating lasers and passive waveguide interconnects progress using standard microelectronics fabrication techniques, makes GQLL the basis for a high-speed photonic logic family.
Date: August 20, 2003
Creator: Bond, T C & Kallman, J K
Object Type: Article
System: The UNT Digital Library
Deployment Options for A Spent Fuel Treatment Facility in the United States (open access)

Deployment Options for A Spent Fuel Treatment Facility in the United States

A promising alternative to direct disposal is to process the commercial spent nuclear fuel into key partitions permitting recovery of some of the energy value while providing vital flexibility to the operation of a repository in a manner to minimize and possibly defer the near-term need for future repositories. It is assumed that such a Spent Fuel Treatment Facility (SFTF) will provide significant benefit to the US nuclear waste program and this paper focuses on key options for deployment of such a facility. The SFTF would partition the spent fuel into manageable components that could be recovered, recycled, or dispositioned as economically beneficial to the overall fuel cycle and/or enhances the repository performance. The goal of the SFTF is to reduce the high level waste volume going to a repository, provide for more effective heat management, enhance the containment performance of the specific waste forms, and provide for energy recovery or transmutation as practical.
Date: November 20, 2003
Creator: Boore, W. Brent & McGuire, David H.
Object Type: Article
System: The UNT Digital Library
Coil Tolerance Impact on Plasma Surface Quality for NCSX (open access)

Coil Tolerance Impact on Plasma Surface Quality for NCSX

The successful operation of the National Compact Stellarator Experiment (NCSX) machine will require producing plasma configurations with good flux surfaces, with a minimum volume of the plasma lost to magnetic islands or stochastic regions. The project goal is to achieve good flux surfaces over 90% of the plasma volume. NCSX is a three period device designed to be operated with iota ranging from {approx}0.4 on axis to {approx}0.7 at the edge. The field errors of most concern are those that are resonant with 3/5 and 3/6 modes (for symmetry preserving field errors) and the 1/2 and 2/3 modes (for symmetry breaking field errors). In addition to losses inherent in the physics configuration itself, there will be losses from field errors arising from coil construction and assembly errors. Some of these losses can be recovered through the use of trim coils or correction coils. The impact of coil tolerances on plasma surface quality is evaluated herein for the NCSX design. The methods used in this evaluation are discussed. The ability of the NCSX trim coils to correct for field errors is also examined. The results are used to set coils tolerances for the various coil systems.
Date: October 20, 2003
Creator: Brooks, Art & Reiersen, Wayne
Object Type: Report
System: The UNT Digital Library
Using Mode of Action to Assess Health Risks from Mixtures of Chemical/Physical Agents (open access)

Using Mode of Action to Assess Health Risks from Mixtures of Chemical/Physical Agents

Interactions between tumor promoters with differing mechanisms of action were examined in male B6C3F1 mice treated with mixtures of dichloroacetate (DCA), trichloroacetate (TCA), and tetrachloride (CT), each of which acts by a different mode of action. Mice were initiated by vinyl carbamate (VC), and then promoted by DCA, TCA, CT, or the pair-wised combinations of the three compounds. The effect of each treatment or treatment combination on tumor number/animal and tumor size was individually assessed at 18, 24, 30 or 36 weeks of treatment. Dose-related increases in tumor size were observed with 20 & 50 mg/kg CT, but each produced equal number of tumors at 36 weeks with the main distinction being a decrease in tumor latency at the higher dose. Overall TCA treatment produced dose-related increases in tumor number at 36 weeks of treatment. Thus, the lower doses of CT and TCA treatments apparently affected tumor size rather than number. Results with DCA were not as clear as a true maximum tumor number was not clearly observed within the experimental period. Treatment of mice receiving a high dose of TCA (2 g/L of drinking water) combined with varying doses of DCA (0.1, 0.5 and 2 g/L) produced increased numbers …
Date: January 20, 2003
Creator: Bull, Richard J.; Lei, Xingye C. & Sasser, Lyle B.
Object Type: Report
System: The UNT Digital Library