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A hybrid ion-source concept for a proton driver front-end

Description: A novel concept for creating intense beams of negative hydrogen ion beams has been devised, and first steps towards its realization have been taken. In this approach, an ECR plasma generator operating at 2.45 GHz frequency is utilized as a plasma cathode, and electrons are extracted instead of ions and injected at moderate energy into an SNS type multi-cusp H{sup -} ion source. This secondary source is then driven by chopped d. c. power, rather than rf power, but does not need filaments which are the cause for the rather short lifetime of conventional H{sup -} sources. The development of this ion source is primarily aimed at the future beam-power goal of 3 MW for the Spallation Neutron Source (SNS) [1] that will be pursued after the start of SNS operations. The first two phases of this development effort have been successfully passed: assembly of a test stand and verification of the performance of an rf-driven SNS ion-source prototype and extraction of electrons with more than 200 mA current from a 2.45-GHz ECR ion source obtained on loan from Argonne National Laboratory. An electron-extraction chamber that joins these ECR and H{sup -} sources has been fabricated, and the next goal is the demonstration of actual H{sup -} ion production by this novel, hybrid ion source. This paper describes the source principle and design in detail, reports on the current status of the development work, and gives an outlook on future lines of development.
Date: October 18, 2004
Creator: Keller, R.; Luft, P.; Regis, M.; Wallig, J.; Monroy, M.; Ratti,A. et al.
Partner: UNT Libraries Government Documents Department

Practical superconductor development for electrical power applications - annual report for FY 2003.

Description: Most large-scale applications of high-critical-temperature superconductors will require conductors that can carry large currents in the presence of applied magnetic fields. This report describes progress at Argonne National Laboratory (ANL) in the research and development of practical superconducting components and devices. These efforts primarily focus on the use of Y-Ba-Cu-O system in second-generation conductors, but they also include investigations of Bi-Pb-Sr-Ca-Cu-O systems for use in first-generation conductors. Results are presented in the areas of processing first-generation superconductors and second-generation (2G) superconductors with several different architectures, applying Raman microscopy to the characterization of 2G conductors, studying the role of oxygen doping in the grain boundary transport of 2G conductors, and evaluating the mechanical properties of 2G conductors.
Date: October 18, 2004
Creator: Balachandran, U.; Baurceanu, R.; Clauss, H.; Dorris, S. E.; Emerson, J. E.; Erck, R. A et al.
Partner: UNT Libraries Government Documents Department

2004 Progress Report for Grant No. DE-FG03-03NA00076 Nuclear Level Densities and Gamma-ray Strength Functions: Stewardship Sciences Academic Alliances Program

Description: To verify the apparent large enhancement of the radiative strength function in light and medium nuclei, the 56Fe(n,2gamma)57Fe reaction was measured. The two-step cascade intensities with soft primary intensities confirm the enhancement. The combined results have been published in Physical Review Letters and featured in the Physics News Update. Data for the Yb isotopes have been combined to examine the systematics of level densities and strength function in three Yb isotopes. A paper on these results have been accepted for publication in Physical Review C. Analysis of the gamma rays from neutron induced reactions on 48Ti have been measured and analyzed for neturon energies from 1 to 250 MeV.
Date: October 18, 2004
Creator: Mitchell, G. E.
Partner: UNT Libraries Government Documents Department

An adaptive radiation model for the origin of new genefunctions

Description: The evolution of new gene functions is one of the keys to evolutionary innovation. Most novel functions result from gene duplication followed by divergence. However, the models hitherto proposed to account for this process are not fully satisfactory. The classic model of neofunctionalization holds that the two paralogous gene copies resulting from a duplication are functionally redundant, such that one of them can evolve under no functional constraints and occasionally acquire a new function. This model lacks a convincing mechanism for the new gene copies to increase in frequency in the population and survive the mutational load expected to accumulate under neutrality, before the acquisition of the rare beneficial mutations that would confer new functionality. The subfunctionalization model has been proposed as an alternative way to generate genes with altered functions. This model also assumes that new paralogous gene copies are functionally redundant and therefore neutral, but it predicts that relaxed selection will affect both gene copies such that some of the capabilities of the parent gene will disappear in one of the copies and be retained in the other. Thus, the functions originally present in a single gene will be partitioned between the two descendant copies. However, although this model can explain increases in gene number, it does not really address the main evolutionary question, which is the development of new biochemical capabilities. Recently, a new concept has been introduced into the gene evolution literature which is most likely to help solve this dilemma. The key point is to allow for a period of natural selection for the duplication per se, before new function evolves, rather than considering gene duplication to be neutral as in the previous models. Here, I suggest a new model that draws on the advantage of postulating selection for gene duplication, and proposes that bursts ...
Date: October 18, 2004
Creator: Francino, M. Pilar
Partner: UNT Libraries Government Documents Department

Federal Funding for Unauthorized Aliens' Emergency Medical Expenses

Description: This report discusses the amount of money spent, as well as the amount of federal funds available to provide emergency medical care to unauthorized (illegal) aliens in the United States. It is extremely difficult to ascertain the amount of money spent for emergency medical care for unauthorized aliens since most hospitals do not ask patients their immigration status. Additionally, prior to the passage of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (P.L. 108-173) on December 8, 2003 there were no federal funds available for the specific purpose of reimbursing hospitals or states for emergency medical care provided to unauthorized aliens (undocumented immigrants).
Date: October 18, 2004
Creator: Siskin, Alison
Partner: UNT Libraries Government Documents Department

Public Community Colleges and Technical Schools: Most Schools Use Both Credit and Noncredit Programs for Workforce Development

Description: A letter report issued by the Government Accountability Office with an abstract that begins "The goal of most American workers--a well-paying job--will be increasingly linked to adequate training in the coming years. Such training will be key to competing for the 21 million new jobs the Department of Labor projects will be created in the 2002 to 2012 period. People already in, or seeking to enter, the workforce often turn to the nation's more than 1,100 public community colleges and technical schools to obtain needed skills. Nearly 6 million students were enrolled in for-credit courses in the fall term 2000 and millions more participated in noncredit courses at these schools. GAO was asked to examine: (1) the extent to which community colleges and technical schools are involved in remedial education and workforce training efforts as well as academic preparation activities; (2) how state and federal funding support these academic and training efforts; and (3) what is known about schools' efforts to measure outcomes, including the rates at which students graduate, transfer to 4-year institutions, pass occupational licensing exams, and gain employment. The scope of our review included a Web-based survey of 1,070 public community colleges and technical schools, 758 (71 percent) of which completed the survey."
Date: October 18, 2004
Creator: United States. Government Accountability Office.
Partner: UNT Libraries Government Documents Department

9/11 Commission: Current Legislative Proposals for U.S. Immigration Law and Policy

Description: This report briefly discusses some of the major immigration areas under consideration in comprehensive reform proposals suggested by the 9/11 Commission, including asylum, biometric tracking systems, border security, document security, exclusion, immigration enforcement, and visa issuances. It refers to other CRS reports that discuss these issues in depth and will be updated as needed.
Date: October 18, 2004
Creator: Garcia, Michael John & Wasem, Ruth Ellen
Partner: UNT Libraries Government Documents Department

Suppression of Large Edge Localized Modes with a Stochastic Magnetic Boundary in High Confinement DIII-D Plasmas

Description: Large sub-millisecond heat pulses due to Type-I ELMs have been reproducibly eliminated in DIII-D for periods approaching 7 energy confinement times with small dc currents driven in a simple magnetic perturbation coil. The current required to eliminate all but a few isolated Type-I ELM impulses during a perturbation coil pulse lasting several seconds is less than 0.4% of plasma current. Based on vacuum magnetic field line modeling, perturbation fields from the coil resonate strongly with plasma flux surfaces across most of the pedestal region (0.9 {le} {psi}{sub N} {le} 1.0) when q95 = 3.7{plus_minus}0.2 creating small remnant magnetic islands surrounded by weakly stochastic field lines. Under the best ELM suppression conditions, the stored energy, {beta}N and H-mode quality factor are unaffected by the perturbation field along with the electron pressure profile, radial electric field and poloidal rotation across the pedestal. Consequently, the H-mode transport barrier and global energy confinement time is also unaltered in these cases. Although some isolated ELM-like events typically occur during the perturbation coil pulse, long periods free of large Type-I ELMs ({Delta}t > 4-6 {tau}{sub E}) have been reproduced numerous times, on multiple experimental run days. Several Type-I ELM suppression and modification behaviors have been identified and studied over a range of discharge conditions including those matching the ITER scenario 2 flux surface shape and aspect ratio scaled down by a factor of 3.5 to fit in the DIII-D vacuum vessel. Since large Type-I ELM impulses represent a severe constraint on the survivability of the divertor target plates in future fusion devices such as ITER, a proven method of eliminating these impulses is critical for the development of tokamak reactors. Results presented in this paper suggest that non-axisymmetric edge magnetic perturbations could be a promising option for controlling ELMs in future tokamaks such as ITER.
Date: October 18, 2004
Creator: Evans, T E; Moyer, R A; Watkins, J G; Osborne, T H; Thomas, P R; Becoulet, M et al.
Partner: UNT Libraries Government Documents Department

Determination of collision rates relevant to Weibel-like instability growth rates in classical and non-classical plasmas encountered in fast-ignition experiments

Description: Analytical simulations of fast-electron currents induced by high-density laser-plasma interactions require estimation of various plasma and beam parameters, including temperatures, densities, and collision rates. This note describes a technique used to estimate or calculate these parameters for the case of contemporary multi-terawatt experiments using foil targets as well as for anticipated fast-ignition-scale experiments.
Date: October 18, 2004
Creator: Hill, J M & Key, M H
Partner: UNT Libraries Government Documents Department

Crystal Level Continuum Modeling of Phase Transformations: The (alpha) <--> (epsilon) Transformation in Iron

Description: We present a crystal level model for thermo-mechanical deformation with phase transformation capabilities. The model is formulated to allow for large pressures (on the order of the elastic moduli) and makes use of a multiplicative decomposition of the deformation gradient. Elastic and thermal lattice distortions are combined into a single lattice stretch to allow the model to be used in conjunction with general equation of state relationships. Phase transformations change the mass fractions of the material constituents. The driving force for phase transformations includes terms arising from mechanical work, from the temperature dependent chemical free energy change on transformation, and from interaction energy among the constituents. Deformation results from both these phase transformations and elasto-viscoplastic deformation of the constituents themselves. Simulation results are given for the {alpha} to {epsilon} phase transformation in iron. Results include simulations of shock induced transformation in single crystals and of compression of polycrystals. Results are compared to available experimental data.
Date: October 18, 2004
Creator: Barton, N R; Benson, D J; Becker, R; Bykov, Y & Caplan, M
Partner: UNT Libraries Government Documents Department

Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak

Description: Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q {approx} 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.
Date: October 18, 2004
Creator: Luce, T C
Partner: UNT Libraries Government Documents Department

ETAII 6 MEV PEPPERPOT EMITTANCE MEASUREMENT

Description: We measured the beam emittance at the ETAII accelerator using a pepper-pot diagnostic at nominal parameters of 6 MeV and 2000 Amperes. During the coarse of these experiments, a ''new tune'' was introduced which significantly improved the beam quality. The source of a background pedestal was investigated and eliminated. The measured ''new tune'' emittance is {var_epsilon}= 8.05 {plus_minus} 0. 53 cm - mr or a normalized emittance of {var_epsilon}{sub n} = 943 {plus_minus} 63 mm - mr In 1990 the ETAII programmatic emphasis was on free electron lasers and the paramount parameter was whole beam brightness. The published brightness for ETAII after its first major rebuild was J = 1 - 3 x 10{sup 8} A/(m - rad){sup 2} at a current and energy of 1000-1400 Amperes and 2.5 MeV. The average normalized emittance derived from table 2 of that report is 864 mm-mr corresponding to a real emittance of 14.8 cm-mr.
Date: October 18, 2004
Creator: Paul, A C; Richardson, R & Weir, J
Partner: UNT Libraries Government Documents Department

Variation of Particle Control with Changes in Divertor Geometry

Description: Recent experiments on DIII-D point to the importance of two factors in determining how effectively the deuterium particle inventory in a tokamak plasma can be controlled through pumping at the divertor target(s): (1) the divertor magnetic balance, i.e., the degree to which the divertor topology is single-null (SN) or double-null (DN), and (2) the direction of the of Bx{divergent}B ion drift with respect to the X-point(s). Changes in divertor magnetic balance near the DN shape have a much stronger effect on the particle exhaust rate at the inner divertor target(s) than on the particle exhaust rate at the outer divertor target(s). The particle exhaust rate for the DN shape is strongest at the outer strike point opposite the Bx{divergent}B ion particle drift direction. Our data suggests that the presence of Bx{divergent}B and ExB ion particle drifts in the scrapeoff layer (SOL) and divertors play an important role in the particle exhaust rates of DN and near-DN plasmas. Particle exhaust rates are shown to depend strongly on the edge (pedestal) density n{sub e,PED}. In the lower range of densities considered in this study, i.e., n{sub e,PED}/ n{sub GREENWALD}&lt;0.4, particle exhaust rates are also found to be approximately proportional to the deuterium recycling intensity in front of the respective plenum entrance. Our results are shown to have implications for particle control in ITER and other future tokamaks.
Date: October 18, 2004
Creator: Petrie, T W; Allen, S L; Brooks, N H; Fenstermacher, M E; Ferron, J R; Greenfield, C M et al.
Partner: UNT Libraries Government Documents Department

ULTRA-CLEAN FISCHER-TROPSCH FUELS PRODUCTION AND DEMONSTRATION PROJECT

Description: The Report Abstract provides summaries of the past year's activities relating to each of the main project objectives. Some of the objectives will be expanded on in greater detail further down in the report. The following objectives have their own addition sections in the report: SFP Construction and Fuel Production, Impact of SFP Fuel on Engine Performance, Fleet Testing at WMATA and Denali National Park, Demonstration of Clean Diesel Fuels in Diesel Electric Generators in Alaska, and Economic Analysis. ICRC provided overall project organization and budget management for the project. ICRC held meetings with various project participants. ICRC presented at the Department of Energy's annual project review meeting. The plant began producing fuel in October 2004. The first delivery of finished fuel was made in March of 2004 after the initial start-up period.
Date: October 18, 2004
Creator: Bergin, Steve
Partner: UNT Libraries Government Documents Department

Conference Paper NFO-7:7th International Conference on Near-Field Optics and Related Technologies

Description: The seventh conference in the NFO conference series, held here in Rochester, provided to be the principal forum for advances in sub-wavelength optics, near-field optical microscopy, local field enhancement, instrumental developments and the ever-increasing range of applications. This conference brought together the diverse scientific communities working on the theory and application of near-field optics (NFO) and related techniques.
Date: October 18, 2004
Creator: Novotny, Prof.Dr. Lukas
Partner: UNT Libraries Government Documents Department

Gas Storage Technology Consortium Quarterly Report

Description: Gas storage is a critical element in the natural gas industry. Producers, transmission and distribution companies, marketers, and end users all benefit directly from the load balancing function of storage. The unbundling process has fundamentally changed the way storage is used and valued. As an unbundled service, the value of storage is being recovered at rates that reflect its value. Moreover, the marketplace has differentiated between various types of storage services, and has increasingly rewarded flexibility, safety, and reliability. The size of the natural gas market has increased and is projected to continue to increase towards 30 trillion cubic feet (TCF) over the next 10 to 15 years. Much of this increase is projected to come from electric generation, particularly peaking units. Gas storage, particularly the flexible services that are most suited to electric loads, is critical in meeting the needs of these new markets. In order to address the gas storage needs of the natural gas industry, an industry-driven consortium was created--the Gas Storage Technology Consortium (GSTC). The objective of the GSTC is to provide a means to accomplish industry-driven research and development designed to enhance operational flexibility and deliverability of the Nation's gas storage system, and provide a cost effective, safe, and reliable supply of natural gas to meet domestic demand. To accomplish this objective, the project is divided into three phases that are managed and directed by the GSTC Coordinator. The first phase, Phase 1A, was initiated on September 30, 2003, and was completed on March 31, 2004. Phase 1A of the project included the creation of the GSTC structure, development and refinement of a technical approach (work plan) for deliverability enhancement and reservoir management. This report deals with Phase 1B and encompasses the period July 1, 2004, through September 30, 2004. During this time period there ...
Date: October 18, 2004
Creator: Watson, Robert W.
Partner: UNT Libraries Government Documents Department