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Beam Simulations for IRE and Driver - Status and Strategy

Description: The methods and codes employed in the U.S. Heavy Ion Fusion program to simulate the beams in an Integrated Research Experiments (IRE) facility and a fusion driver are presented in overview. A new family of models incorporating accelerating module impedance, multi-beam, and self-magnetic effects is described, and initial WARP3d particle simulations of beams using these models are presented. Finally, plans for streamlining the machine-design simulation sequence, and for simulating beam dynamics f… more
Date: March 13, 2001
Creator: Friedman, A; Grote, D P & Lee, E P
Partner: UNT Libraries Government Documents Department
open access

Heats of Formation of Energetic Oxetane Monomers and Polymers

Description: Energetic oxetane polymers have shown promise as performance-enhancing ingredients in gun and missile propellants. In order to correctly predict the performance of energetic materials containing these polymers, it is important to have accurate, experimentally determined values for the polymer heats of formation ({Delta}H{sub f}). In support of a theoretical study on gun propellant performance, heats of combustion were experimentally determined for a series of oxetane polymers and monomers (see … more
Date: March 21, 2001
Creator: Schmidt, R D & Manser, G E
Partner: UNT Libraries Government Documents Department
open access

Status of Optical Coatings for the National Ignition Facility

Description: Optical coatings are a crucial part of the pulse trapping and extraction in the NIF multipass amplifiers. Coatings also steer the 192 beams from four linear arrays to four converging cones entering the target chamber. There are a total of 1600 physical vapor deposited coatings on NIF consisting of 576 mirrors within the multipass cavity, 192 polarizers that work in tandem with a Pockels cell to create an optical switch, and 832 transport mirrors. These optics are of sufficient size so that they… more
Date: March 5, 2001
Creator: Stolz, C. J.; Weinzapfel, C.; Rogowski, G. T.; Smith, D.; Rigatti, A.; Oliver, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Thermal Decomposition of Trinitrotoluene (TNT) with a New One-Dimensional Time to Explosion (ODTX) Apparatus

Description: The thermal explosion of trinitrotoluene (TNT) is used as a basis for evaluating the performance of a new One-Dimensional-Time-to-Explosion (ODTX) apparatus. The ODTX experiment involves holding a 12.7 mm-diameter spherical explosive sample under confinement (150 MPa) at a constant elevated temperature until the confining pressure is exceeded by the evolution of gases during chemical decomposition. The resulting time to explosion as a function of temperature provides valuable decomposition kine… more
Date: March 23, 2001
Creator: Tran, T. D.; Simpson, R. L.; Maienschein, J. & Tarver, Craig M.
Partner: UNT Libraries Government Documents Department
open access

Relative Advantages of Direct and Indirect Drive for an Inertial Fusion Energy Power Plant Driven by a Diode-Pumped Solid-State Laser

Description: This paper reviews our current understanding of the relative advantages of direct drive (DD) and indirect drive (ID) for a 1 GWe inertial fusion energy (IFE) power plant driven by a diode-pumped solid-state laser (DPSSL). This comparison is motivated by a recent study (1) that shows that the projected cost of electricity (COE) for DD is actually about the same as that for ID even though the target gain for DD can be much larger. We can therefore no longer assume that DD is the ultimate targetin… more
Date: March 6, 2001
Creator: Orth, C D
Partner: UNT Libraries Government Documents Department
open access

Operation of a Four-Cylinder 1.9L Propane Fueled Homogeneous Charge Compression Ignition Engine: Basic Operating Characteristics and Cylinder-to-Cylinder Effects

Description: A four-cylinder 1.9 Volkswagen TDI Engine has been converted to run in Homogeneous Charge Compression Ignition (HCCI) mode. The stock configuration is a turbocharged direct injection Diesel engine. The combustion chamber has been modified by discarding the in-cylinder Diesel fuel injectors and replacing them with blank inserts (which contain pressure transducers). The stock pistons contain a reentrant bowl and have been retained for the tests reported here. The intake and exhaust manifolds have… more
Date: March 12, 2001
Creator: Flowers, D.; Aceves, S. M.; Martinez-Frias, J.; Smith, J. R.; Au, M.; Girard, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Defects Induced in Fused Silica by High Power UV Laser Pulses at 355 nm

Description: Point defects induced in high quality optical-grade based silica by high power (>30 J/cm{sup 2}) 355 nm laser pulses have been investigated to elucidate the nature of laser damage in transparent optics designed for use at the National Ignition Facility (NIF). Six defects have been identified: the NBOHC (non-bridging oxygen hole center), a STE (self-trapped exciton), an ODC (oxygen-deficient center), interstitial oxygen, the E'{sub {gamma}}, and E'{sub 74}. The former four defects were identi… more
Date: March 23, 2001
Creator: Stevens-Kalceff, M A; Stesmans, A & Wong, J
Partner: UNT Libraries Government Documents Department
open access

Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements

Description: People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this pape… more
Date: March 20, 2001
Creator: Candy, J V & Meyer, A W
Partner: UNT Libraries Government Documents Department
open access

Beam Extraction from Laser Driven Multi-Charged Ion Source

Description: A newly proposed type of multicharged ion source offers the possibility of an economically advantageous high-charge-state fusion driver. Multiphoton absorption in an intense uniform laser focus can give multiple charge states of high purity, simplifying or eliminating the need for charge-state separation downstream. Very large currents (hundreds of amperes) can be extracted from this type of source. Several arrangements are possible. For example, the laser plasma could be tailored for storage i… more
Date: March 19, 2001
Creator: Anderson, O. A. & Logan, B. G.
Partner: UNT Libraries Government Documents Department
open access

Analysis of Geomechanical Behavior for the Drift Scale Test

Description: The Drift Scale Test (DST) now underway at Yucca Mountain has been simulated using a Drift Scale Distinct Element (DSDE) model. Simulated deformations show good agreement with field deformation measurements. Results indicate most fracture deformation is located above the crown of the Heated Drift. This work is part of the model validation effort for the DSDE model, which is used to assess thermal-mechanical effects on the hydrology of the rock mass surrounding a potential repository.
Date: March 5, 2001
Creator: Blair, S. C.; Carlson, S. R. & Wagoner, J. L.
Partner: UNT Libraries Government Documents Department
open access

Ab initio Calculation of Thermodynamic Data for Oxygenated Hydrocarbon Fuels and Radial Breakdown Species: R(OMe)n

Description: There has long been interest in the use of oxygenated hydrocarbon additives to conventional fuels. These oxygenates have been shown to reduce soot emissions in diesel engines and CO emissions in spark-ignition engines; and often allow diesel operation with decreased NO{sub x}. The current widely used additive, MTBE is targeted for elimination as a gasoline additive due to its damaging effects on the environment. This creates a need for alternative oxygenated additives; and more importantly, amp… more
Date: March 23, 2001
Creator: Kubota, A; Pitz, W J; Westbrook, C K; Bozzelli, J & Glaude, P-A
Partner: UNT Libraries Government Documents Department
open access

Ab-Initio No-Core Shell Model

Description: We discuss the no-core shell model approach, an ab initio method with effective Hamiltonians derived from realistic nucleon-nucleon (NN) potentials as a function of the finite harmonic-oscillator (HO) basis space. We present results for three and four nucleon systems in model spaces that include up to 50{Dirac_h}{Omega} and 18{bar h}{Omega} HO excitations, respectively. For these light systems we are in agreement with results obtained by other exact methods. Also, we calculate the properties of… more
Date: March 2, 2001
Creator: Barrett, B R; Navratil, P; Vary, J P & Ormand, W E
Partner: UNT Libraries Government Documents Department
open access

Divertor Target Heat Load Reduction by Electrical Biasing, and Application to COMPASS-D

Description: A toroidally-asymmetric potential structure in the scrape-off layer (SOL) plasma may be formed by toroidally distributed electrical biasing of the divertor target tiles. The resulting ExB convective motions should increase the plasma radial transport in the SOL and thereby reduce the heat load at the divertor [1]. In this paper we develop theoretical modeling and describe the implementation of this concept to the COMPASS-D divertor. We show that strong magnetic shear near the X-point should cau… more
Date: March 7, 2001
Creator: Fielding, S. J.; Cohen, R. H.; Helander, P. & Ryutov, D. D.
Partner: UNT Libraries Government Documents Department
open access

Photothermal Properties of Shape Memory Polymer Micro-Actuators for Treating Stroke

Description: Objective--In this paper the photothermal design aspects of novel shape memory polymer (SMP) microactuators for treating stroke are presented. Materials and Methods--A total of three devices will be presented: two interventional ischemic stroke devices (coil and umbrella) and one device for releasing embolic coils (microgripper). The optical properties of SMP, methods for coupling laser light into SMP, heating distributions in the SMP devices and the impact of operating the thermally activated … more
Date: March 5, 2001
Creator: Maitland, D J; Metzger, M F; Schumann, D; Lee, A & Wilson, T S
Partner: UNT Libraries Government Documents Department
open access

Evaluation of the Impact of CO2, Aqueous Fluid, and Reservoir Rock Interactions on the Geologic Sequestration of CO2 with Special Emphasis on Economic Implications

Description: Lowering the costs of front-end processes in the geologic sequestration of CO{sub 2} can dramatically lower the overall costs. One approach is to sequester less-pure CO{sub 2} waste streams that are less expensive or require less energy to separate from flue gas, a coal gasification process, etc. The objective of this research is to evaluate the impacts of an impure CO{sub 2} waste stream on geologic sequestration using both reaction progress and reactive transport simulators. The simulators se… more
Date: March 8, 2001
Creator: Knauss, K. G.; Johnson, J. W.; Steefel, C. I. & Nitao, J. J.
Partner: UNT Libraries Government Documents Department
open access

Combining a Multithreaded Scene Graph System with a Tiled Display Environment

Description: This case study highlights the technical challenges of creating an application that uses a multithreaded scene graph toolkit for rendering and uses a software environment for management of tiled display systems. Scene graph toolkits simplify and streamline graphics applications by providing data management and rendering services. Software for tiled display environments typically performs device and event management by opening windows on displays, by gathering and processing input device events,… more
Date: March 29, 2001
Creator: Frank, R & Bethel, W
Partner: UNT Libraries Government Documents Department
open access

Detailed Chemical Kinetic Reaction Mechanisms for Combustion of Isomers of Heptane

Description: Detailed chemical kinetic reaction mechanisms are developed for all nine chemical isomers of heptane (C{sub 7}H{sub 16}), following techniques and models developed previously for other smaller alkane hydrocarbon species. These reaction mechanisms are tested at high temperatures by computing shock tube ignition delay times and at lower temperatures by simulating ignition in a rapid compression machine. Although the corresponding experiments have not been reported in the literature for most of th… more
Date: March 26, 2001
Creator: Westbrook, C K; Pitz, W J; Curran, H C; Boercker, J & Kunrath, E
Partner: UNT Libraries Government Documents Department
open access

Visualization of Mixing and Combustion in TNT Explosions

Description: Numerical simulations are used to visualize the mixing and combustion induced by explosions of spherical and cylindrical TNT charges. Evolution of the exothermic energy is controlled by mixing (vorticity), which is strongly influenced by wave reflections from confining walls.
Date: March 26, 2001
Creator: Kuhl, A L; Ferguson, R E; Oppenheim, A K & Seizew, M R
Partner: UNT Libraries Government Documents Department
open access

Advances in understanding paternally transmitted Chromosomal Abnormalities

Description: Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitte… more
Date: March 1, 2001
Creator: Marchetti, F; Sloter, E & Wyrobek, A J
Partner: UNT Libraries Government Documents Department
open access

Type 1 Frequency Doubling at 1064 nm in LaCa40(B03)3 (LaCOB), GdCa40(B03)3(GdCOB), and YCa40(B03)3(YCOB)

Description: We have grown and characterized LaCOB, a new member to the GdCOB family of nonlinear crystals. LaCOB has a d{sub eff} of 0.52 {plus_minus} 0.05 pm/V and an angular sensitivity of 1224 {plus_minus} 184 (cm-rad){sup -1} for type I frequency doubling at 1064 nm. The d{sub {alpha}{beta}{beta}} and d{sub {gamma}{beta}{beta}} coefficients of the nonlinear optical tensor for LaCOB, GdCOB, and YCOB were determined to have values of {vert_bar}0.26 {plus_minus} 0.04{vert_bar} pm/V and |1.69 {plus_minus} … more
Date: March 7, 2001
Creator: Adams, J. J.; Ebbers, C. A.; Schaffers, K. I. & Payne, S. A.
Partner: UNT Libraries Government Documents Department
open access

''A Wavelet Optimized Adaptive, High-Order, Multi-Domain Method for Parallel Architectures''

Description: Constructing numerical schemes which are both adaptive and suitable for parallel architectures is very challenging. The challenge lies in the need to maintain a balanced load across the processing elements using a method that is both efficient and scalable. Here we propose a method which is adaptive, load balanced, absolutely efficient and scalable offering significant speedup over lower order adaptive schemes. The ability of wavelets to accurately and efficiently represent functions with local… more
Date: March 27, 2001
Creator: Jameson, L M; Johnson, J R & Hesthaven, J S
Partner: UNT Libraries Government Documents Department
open access

Microsats for On-Orbit Support Missions

Description: I appreciate the opportunity to address this conference and describe some of our work and plans for future space missions and capabilities. My presentation will consist of a short overview of our program, some potential missions and enabling technologies, as well as, a description of some of our test vehicles and ongoing docking experiments. The Micro-Satellite Technology Program at Lawrence Livermore National Laboratory is developing technologies for a new generation of a very highly capable a… more
Date: March 15, 2001
Creator: Ledebuhr, A G
Partner: UNT Libraries Government Documents Department
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