Multilayer deposition and EUV reflectance characterization of 131 ? flight mirrors for AIA at LLNL (open access)

Multilayer deposition and EUV reflectance characterization of 131 ? flight mirrors for AIA at LLNL

Mo/Si multilayer coatings reflecting at 131 {angstrom} were deposited successfully on the AIA primary and secondary flight mirrors and on two coating witness Si wafers, on November 16, 2005, at LLNL. All coatings were characterized by means of EUV reflectance measurements at beamline 6.3.2 of the Advanced Light Source (ALS) synchrotron at LBNL, and were found to be well within specifications.
Date: February 22, 2006
Creator: Soufli, R; Robinson, J C; Spiller, E; Baker, S L; Dollar, F J & Gullikson, E M
Object Type: Report
System: The UNT Digital Library
Sensitivity Analysis of the DARHT-II 2.5MV/2kA Diode (open access)

Sensitivity Analysis of the DARHT-II 2.5MV/2kA Diode

This report summarizes the study of the tolerance limits on the assembly of the cathode and the Pierce electrode for the DARHT-II diode (2.5 MV, 2 kA case), performed through a series of computer simulations using the PIC code WARP [1]. We have considered sources of beam quality degradation like the errors in axial and transverse positioning, and the size of the radial gap between the cathode and the Pierce electrode (shroud). The figure of merit was chosen to be the RMS beam (edge) emittance at a distance of 1 meter from the cathode, as defined by {var_epsilon}{sub x} = 4 {beta}{gamma} {radical}(<x{sup 2}><x{prime}{sup 2}>-<xx{prime}>{sup 2}) {center_dot}. The analysis shows that to position the cathode at the correct axial and transverse location is more important than the size of the radial gap.
Date: December 22, 2006
Creator: Henestroza, Enrique
Object Type: Report
System: The UNT Digital Library
EUV reflectance characterization of the 94/304 ? flight secondary AIA mirror at beamline 6.3.2 of the Advanced Light Source (open access)

EUV reflectance characterization of the 94/304 ? flight secondary AIA mirror at beamline 6.3.2 of the Advanced Light Source

The AIA secondary flight mirror, previously coated at Columbia University with Mg/SiC for the 303.8 {angstrom} channel and Mo/Y for the 93.9 {angstrom} channel was characterized by means of EUV reflectance measurements at beamline 6.3.2 of the Advanced Light Source (ALS) synchrotron at LBNL on January 10, 2006. Paul Boerner (LMSAL) also participated in these measurements.
Date: February 22, 2006
Creator: Soufli, R; Spiller, E; Aquila, A. L.; Gullikson, E. M. & Windt, D. L.
Object Type: Report
System: The UNT Digital Library
Delineation of a Wellhead Protection Zone and Determination of Flowpaths From Potential Groundwater Contaminant Source Areas at Camp Ripley, Little Falls, Minnesota. (open access)

Delineation of a Wellhead Protection Zone and Determination of Flowpaths From Potential Groundwater Contaminant Source Areas at Camp Ripley, Little Falls, Minnesota.

None
Date: December 22, 2006
Creator: Quinn, J. J. & Division, Environmental Science
Object Type: Report
System: The UNT Digital Library
Measurement of the relaxation time of hot electrons in laser-solid interaction at relativistic laser intensities (open access)

Measurement of the relaxation time of hot electrons in laser-solid interaction at relativistic laser intensities

The authors have measured the relaxation time of hot electrons in short pulse laser-solid interactions using a picosecond time-resolved x-ray spectrometer and a time-integrated electron spectrometer. Employing laser intensities of 10{sup 17}, 10{sup 18}, and 10{sup 19} W/cm{sup 2}, they find increased laser coupling to hot electrons as the laser intensity becomes relativistic and thermalization of hot electrons at timescales on the order of 10 ps at all laser intensities. They propose a simple model based on collisional coupling and plasma expansion to describe the rapid relaxation of hot electrons. The agreement between the resulting K{sub {alpha}} time-history from this model with the experiments is best at highest laser intensity and less satisfactory at the two lower laser intensities.
Date: August 22, 2006
Creator: Chen, H; Shepherd, R; Chung, H K; Dyer, G; Faenov, A; Fournier, K B et al.
Object Type: Article
System: The UNT Digital Library
Development of an Ultra-fine Coal Dewatering Technology and an Integrated Flotation-Dewatering System for Coal Preparation Plants (open access)

Development of an Ultra-fine Coal Dewatering Technology and an Integrated Flotation-Dewatering System for Coal Preparation Plants

The project proposal was approved for only the phase I period. The goal for this Phase I project was to develop an industrial model that can perform continuous and efficient dewatering of fine coal slurries of the previous flotation process to fine coal cake of {approx}15% water content from 50-70%. The feasibility of this model should be demonstrated experimentally using a lab scale setup. The Phase I project was originally for one year, from May 2005 to May 2006. With DOE approval, the project was extended to Dec. 2006 without additional cost from DOE to accomplish the work. Water has been used in mining for a number of purposes such as a carrier, washing liquid, dust-catching media, fire-retardation media, temperature-control media, and solvent. When coal is cleaned in wet-processing circuits, waste streams containing water, fine coal, and noncombustible particles (ash-forming minerals) are produced. In many coal preparation plants, the fine waste stream is fed into a series of selection processes where fine coal particles are recovered from the mixture to form diluted coal fine slurries. A dewatering process is then needed to reduce the water content to about 15%-20% so that the product is marketable. However, in the dewatering process …
Date: December 22, 2006
Creator: Zhang, Wu; Yang, David; Amarnath, Amar; Huq, Iftikhar; O'Brien, Scott & Williams, Jim
Object Type: Report
System: The UNT Digital Library
Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution (open access)

Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution

Monte Carlo simulations are used to establish the potential of mean force between two globular proteins in an aqueous electrolyte solution. This potential includes nonelectrostatic contributions arising from dispersion forces first, between the globular proteins, and second, between ions in solution and between each ion and the globular protein. These latter contributions are missing from standard models. The potential of mean force, obtained from simulation, is fitted to an analytic equation. Using our analytic potential of mean force and Barker-Henderson perturbation theory, we obtain phase diagrams for lysozyme solutions that include stable and metastable fluid-fluid and solid-fluid phases when the electrolyte is 0.2 M NaSCN or NaI or NaCl. The nature of the electrolyte has a significant effect on the phase diagram.
Date: February 22, 2006
Creator: Bostrom, Mathias; Tavares, Frederico W.; Ninham, Barry W. & Prausnitz, John M.
Object Type: Article
System: The UNT Digital Library
Non equilibrium dynamics of mixing, oscillations, and equilibration: A model study (open access)

Non equilibrium dynamics of mixing, oscillations, and equilibration: A model study

The non-equilibrium dynamics of mixing, oscillations and equilibration is studied in a field theory of flavored neutral mesons that effectively models two flavors of mixed neutrinos, in interaction with other mesons that represent a thermal bath of hadrons or quarks and charged leptons. This model describes the general features of neutrino mixing and relaxation via charged currents in a medium. The reduced density matrix and the non-equilibrium effective action that describes the propagation of neutrinos is obtained by integrating out the bath degrees of freedom. We obtain the dispersion relations, mixing angles and relaxation rates of ``neutrino'' quasiparticles. The dispersion relations and mixing angles are of the same form as those of neutrinos in the medium, and the relaxation rates are given by $\Gamma_1(k) = \Gamma_{ee}(k) \cos^2\theta_m(k)+\Gamma_{\mu\mu}(k)\sin^2\theta_m(k); \Gamma_2(k)= \Gamma_{\mu\mu}(k) \cos^2\theta_m(k)+\Gamma_{ee}(k)\sin^2\theta_m(k) $ where $\Gamma_{\alpha\alpha}(k)$ are the relaxation rates of the flavor fields in \emph{absence} of mixing, and $\theta_m(k)$ is the mixing angle in the medium. A Weisskopf-Wigner approximation that describes the asymptotic time evolution in terms of a non-hermitian Hamiltonian is derived. At long time $>>\Gamma^{-1}_{1,2}$ ``neutrinos'' equilibrate with the bath. The equilibrium density matrix is nearly diagonal in the basis of eigenstates of an \emph{effective Hamiltonian that includes self-energy corrections …
Date: December 22, 2006
Creator: Ho, Chiu Man; Boyanovsky, D. & Ho, C. M.
Object Type: Article
System: The UNT Digital Library
Benchmarking of Resrad-Offsite : Transition From Resrad (Onsite) Toresrad-Offsite and Comparison of the Resrad-Offsite Predictions With Peercodes. (open access)

Benchmarking of Resrad-Offsite : Transition From Resrad (Onsite) Toresrad-Offsite and Comparison of the Resrad-Offsite Predictions With Peercodes.

The main purpose of this report is to document the benchmarking results and verification of the RESRAD-OFFSITE code as part of the quality assurance requirements of the RESRAD development program. This documentation will enable the U.S. Department of Energy (DOE) and its contractors, and the U.S. Nuclear Regulatory Commission (NRC) and its licensees and other stakeholders to use the quality-assured version of the code to perform dose analysis in a risk-informed and technically defensible manner to demonstrate compliance with the NRC's License Termination Rule, Title 10, Part 20, Subpart E, of the Code of Federal Regulations (10 CFR Part 20, Subpart E); DOE's 10 CFR Part 834, Order 5400.5, ''Radiation Protection of the Public and the Environment''; and other Federal and State regulatory requirements as appropriate. The other purpose of this report is to document the differences and similarities between the RESRAD (onsite) and RESRAD-OFFSITE codes so that users (dose analysts and risk assessors) can make a smooth transition from use of the RESRAD (onsite) code to use of the RESRAD-OFFSITE code for performing both onsite and offsite dose analyses. The evolution of the RESRAD-OFFSITE code from the RESRAD (onsite) code is described in Chapter 1 to help the dose …
Date: May 22, 2006
Creator: Yu, C.; Gnanapragasam, E.; Cheng, J. J. & Biwer, B.
Object Type: Report
System: The UNT Digital Library
In-Plant Testing of High-Efficiency Hydraulic Separators, Phase II Annual Technical Progress Report: 2005 (open access)

In-Plant Testing of High-Efficiency Hydraulic Separators, Phase II Annual Technical Progress Report: 2005

Hydraulic separators are commonly used for particle size classification and gravity concentration of minerals and coal. Unfortunately, the efficiency of these processes can be quite low due to poor equipment design and variations in feed consistency. To help alleviate these problems, an industry-driven R&D program has been undertaken to develop a new generation of hydraulic separators that are more efficient and less costly to operate and maintain. These units, which are commercially called the CrossFlow separator and HydroFloat separator, have the potential to improve performance (separation efficiency and throughput) and reduce operating costs (power consumption, water and reagent usage). In Phase I of this project, laboratory and pilot-scale test units were evaluated at various industrial sites in both the coal and mineral industries. Based on promising results obtained from Phase I, full-scale prototypes were purchased and installed by a major U.S. phosphate producer and a large eastern U.S. coal company. The test data obtained from these sites demonstrate that significant performance improvements can be realized through the application of these high-efficiency separators.
Date: May 22, 2006
Creator: Luttrell, G. H.; Honaker, R. Q.; Bratton, R. C.; Westerfield, T. C. & Kohmuench, J. N.
Object Type: Report
System: The UNT Digital Library
Safety Evaluation of the Single Shell Tanks (SST) Modified Sluicing Waste Retrieval System (open access)

Safety Evaluation of the Single Shell Tanks (SST) Modified Sluicing Waste Retrieval System

None
Date: May 22, 2006
Creator: Smith, R. D.
Object Type: Report
System: The UNT Digital Library
Generation of Tones Due to Flow past a Deep Cavity: Effect of Streamwise Length (open access)

Generation of Tones Due to Flow past a Deep Cavity: Effect of Streamwise Length

None
Date: May 22, 2006
Creator: Yang, Y; Rockwell, D; Cody, K Lai-Fook & Pollack, M
Object Type: Report
System: The UNT Digital Library
A comparison of model short-range forecasts and the ARM Microbase data (open access)

A comparison of model short-range forecasts and the ARM Microbase data

For the fourth quarter ARM metric we will make use of new liquid water data that has become available, and called the 'Microbase' value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Tropical West Pacific (TWP) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both TWP and NSA. The Microbase data have been averaged to 35 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averaged to 3hourly data for direct comparison to our model output.
Date: September 22, 2006
Creator: Hnilo, J J
Object Type: Report
System: The UNT Digital Library
Revisiting the Cape Cod Bacteria Injection Experiment Using a Stochastic Modeling Approach (open access)

Revisiting the Cape Cod Bacteria Injection Experiment Using a Stochastic Modeling Approach

Bromide and resting-cell bacteria tracer tests carried out in a sand and gravel aquifer at the USGS Cape Cod site in 1987 were reinterpreted using a three-dimensional stochastic approach and Lagrangian particle tracking numerical methods. Bacteria transport was strongly coupled to colloid filtration through functional dependence of local-scale colloid transport parameters on hydraulic conductivity and seepage velocity in a stochastic advection-dispersion/attachment-detachment model. Information on geostatistical characterization of the hydraulic conductivity (K) field from a nearby plot was utilized as input that was unavailable when the original analysis was carried out. A finite difference model for groundwater flow and a particle-tracking model of conservative solute transport was calibrated to the bromide-tracer breakthrough data using the aforementioned geostatistical parameters. An optimization routine was utilized to adjust the mean and variance of the lnK field over 100 realizations such that a best fit of a simulated, average bromide breakthrough curve is achieved. Once the optimal bromide fit was accomplished (based on adjusting the lnK statistical parameters in unconditional simulations), a stochastic particle-tracking model for the bacteria was run without adjustments to the local-scale colloid transport parameters. Good predictions of the mean bacteria breakthrough data were achieved using several approaches for modeling components of …
Date: November 22, 2006
Creator: Maxwell, R M; Welty, C & Harvey, R W
Object Type: Article
System: The UNT Digital Library
2006 XSD Scientific Software Workshop report. (open access)

2006 XSD Scientific Software Workshop report.

In May of 2006, a committee was formed to assess the fundamental needs and opportunities in scientific software for x-ray data reduction, analysis, modeling, and simulation. This committee held a series of discussions throughout the summer, conducted a poll of the members of the x-ray community, and held a workshop. This report details the findings and recommendations of the committee. Each experiment performed at the APS requires three crucial ingredients: the powerful x-ray source, an optimized instrument to perform measurements, and computer software to acquire, visualize, and analyze the experimental observations. While the APS has invested significant resources in the accelerator, investment in other areas such as scientific software for data analysis and visualization has lagged behind. This has led to the adoption of a wide variety of software with variable levels of usability. In order to maximize the scientific output of the APS, it is essential to support the broad development of real-time analysis and data visualization software. As scientists attack problems of increasing sophistication and deal with larger and more complex data sets, software is playing an ever more important role. Furthermore, our need for excellent and flexible scientific software can only be expected to increase, as the …
Date: January 22, 2006
Creator: Evans, K., Jr.; De Carlo, F.; Jemian, P.; Lang, J.; Lienert, U.; Maclean, J. et al.
Object Type: Report
System: The UNT Digital Library
Enhancement of T1 and T2 relaxation by paramagnetic silica-coated nanocrystals (open access)

Enhancement of T1 and T2 relaxation by paramagnetic silica-coated nanocrystals

None
Date: September 22, 2006
Creator: Gerion, D; Herberg, J; Gjersing, E; Ramon, E; Maxwell, R; Gray, J W et al.
Object Type: Article
System: The UNT Digital Library
Osmotic Coefficients, Solubilities, and Deliquescence Relations in Mixed Aqueous Salt Solutions at Elevated Temperature (open access)

Osmotic Coefficients, Solubilities, and Deliquescence Relations in Mixed Aqueous Salt Solutions at Elevated Temperature

While thermodynamic properties of pure aqueous electrolytes are relatively well known at ambient temperature, there are far fewer data for binary systems extending to elevated temperatures and high concentrations. There is no general theoretically sound basis for prediction of the temperature dependence of ionic activities, and consequently temperature extrapolations based on ambient temperature data and empirical equations are uncertain and require empirical verification. Thermodynamic properties of mixed brines in a wide range of concentrations would enhance the understanding and precise modeling of the effects of deliquescence of initially dry solids in humid air in geological environments and in modeling the composition of waters during heating, cooling, evaporation or condensation processes. These conditions are of interest in the analysis of waters on metal surfaces at the proposed radioactive waste repository at Yucca Mountain, Nevada. The results obtained in this project will be useful for modeling the long-term evolution of the chemical environment, and this in turn is useful for the analysis of the corrosion of waste packages. In particular, there are few reliable experimental data available on the relationship between relative humidity and composition that reveals the eutonic points of the mixtures and the mixture deliquescence RH. The deliquescence RH for …
Date: February 22, 2006
Creator: Gruszkiewicz, M. S. & Palmer, D. A.
Object Type: Report
System: The UNT Digital Library
Atomic Force Microscope (AFM) measurements and analysis on Sagem 05R0025 secondary substrate (open access)

Atomic Force Microscope (AFM) measurements and analysis on Sagem 05R0025 secondary substrate

The summary of Atomic Force Microscope (AFM) on Sagem 05R0025 secondary substrate: (1) 2 x 2 {micro}m{sup 2} and 10 x 10 {micro}m{sup 2} AFM measurements and analysis on Sagem 05R0025 secondary substrate at LLNL indicate rather uniform and extremely isotropic finish across the surface, with high-spatial frequency roughness {sigma} in the range 5.1-5.5 {angstrom} rms; (2) the marked absence of pronounced long-range polishing marks in any direction, combined with increased roughness in the very high spatial frequencies, are consistent with ion-beam polishing treatment on the surface. These observations are consistent with all earlier mirrors they measured from the same vendor; and (3) all data were obtained with a Digital Instruments Dimension 5000{trademark} atomic force microscope.
Date: February 22, 2006
Creator: Soufli, R; Baker, S L & Robinson, J C
Object Type: Report
System: The UNT Digital Library
cctbx news (open access)

cctbx news

The 'Computational Crystallography Toolbox' (cctbx, http://cctbx.sourceforge.net/) is the open-source component of the Phenix project (http://www.phenix-online.org/). Most recent cctbx developments are geared towards supporting new features of the phenix.refine application. Thus, the open-source mmtbx (macromolecular toolbox) module is currently being most rapidly developed. In this article we give an overview of some of the recent developments. However, the main theme of this article is the presentation of a light-weight example command-line application that was specifically developed for this newsletter: sequence alignment and superposition of two molecules read from files in PDB format. This involves parameter input based on the Phil module presented in Newsletter No. 5, fast reading of the PDB files with the new iotbx.pdb.input class, simple sequence alignment using the new mmtbx.alignment module, and use of the Kearsley (1989) superposition algorithm to find the least-squares solution for superposing C-alpha positions. The major steps are introduced individually, followed by a presentation of the complete application. The example application is deliberately limited in functionality to make it concise enough for this article. The main goal is to show how the open-source components are typically combined into an application. Even though the example is quite specific to macromolecular crystallography, we believe it …
Date: November 22, 2006
Creator: Grosse-Kunstleve, Ralf W.; Zwart, Peter H.; Afonine, Pavel V.; Ioerger, Thomas R. & Adams, Paul D.
Object Type: Article
System: The UNT Digital Library
ALE3D Simulations of Gap Closure and Surface Ignition for Cookoff Modeling (open access)

ALE3D Simulations of Gap Closure and Surface Ignition for Cookoff Modeling

We are developing ALE3D models to describe the thermal, chemical and mechanical behavior during the heating, ignition and explosive phases of various cookoff phenomena. The candidate models and numerical strategies are being evaluated using benchmark cookoff experiments. ALE3D is a three-dimensional computer code capable of solving the model equations in a coupled fashion through all the phases of the cookoff in a single calculation. For the cookoff experiments, we are interested in representing behavior on widely varying timescales. We have used an implicit hydrodynamics option during the heating phase and an explicit solution method during the explosive phase. To complicate the modeling problem, high heat fluxes cause rapid temperature increases in boundary layers and lead to the formation of gaps between energetic and structural materials and ignition on surfaces. The initially solid energetic and structural materials react to produce gases, which fill the gaps. These materials can also melt and flow. Since an implicit solution method is used, simple no-strength materials models can no longer be used for liquids and gases. In this paper, we discuss and demonstrate choices of materials models for solid/liquid/gas mixtures to be used in conjunction with the implicit solution method. In addition, results are given …
Date: June 22, 2006
Creator: Howard, W. M.; McClelland, M. A. & Nichols, A. L.
Object Type: Article
System: The UNT Digital Library
FY04&05 LDRD Final Report Fission Fragment Sputtering (open access)

FY04&05 LDRD Final Report Fission Fragment Sputtering

Fission fragments born within the first 7 {micro}m of the surface of U metal can eject a thousand or more atoms per fission event. Existing data in the literature show that the sputtering yield ranges from 10 to 10,000 atoms per fission event near the surface, but nothing definitive is known about the energy of the sputtered clusters. Experimental packages were constructed allowing the neutron irradiation of natural uranium foils to investigate the amount of material removed per fission event and the kinetic energy distribution of the sputtered atoms. Samples were irradiated but were never analyzed after irradiation. Similar experiments were attempted in a non-radioactive environment using accelerator driven ions in place of fission induced fragments. These experiments showed that tracks produced parallel to the surface (and not perpendicular to the surface) are the primary source of the resulting particulate ejecta. Modeling studies were conducted in parallel with the experimental work. Because the reactor irradiation experiments were not analyzed, data on the energy of the resulting particulate ejecta was not obtained. However, some data was found in the literature on self sputtering of {sup 252}Cf that was used to estimate the velocity and hence the energy of the ejected particulates. …
Date: February 22, 2006
Creator: Ebbinghaus, B.; Trelenberg, T.; Meier, T.; Felter, T.; Sturgeon, J.; Kuboda, A. et al.
Object Type: Report
System: The UNT Digital Library
Uranium-lead isotope systematics of Mars inferred from the basaltic shergottite QUE 94201 (open access)

Uranium-lead isotope systematics of Mars inferred from the basaltic shergottite QUE 94201

Uranium-lead ratios (commonly represented as {sup 238}U/{sup 204}Pb = {mu}) calculated for the sources of martian basalts preserve a record of petrogenetic processes that operated during early planetary differentiation and formation of martian geochemical reservoirs. To better define the range of {mu} values represented by the source regions of martian basalts, we completed U-Pb elemental and isotopic analyses on whole rock, mineral and leachate fractions from the martian meteorite Queen Alexandra Range 94201 (QUE 94201). The whole rock and silicate mineral fractions have unradiogenic Pb isotopic compositions that define a narrow range ({sup 206}Pb/{sup 204}Pb = 11.16-11.61). In contrast, the Pb isotopic compositions of weak HCl leachates are more variable and radiogenic. The intersection of the QUE 94201 data array with terrestrial Pb in {sup 206}Pb/{sup 204}Pb-{sup 207}Pb/{sup 204}Pb-{sup 208}Pb/{sup 204}Pb compositional space is consistent with varying amounts of terrestrial contamination in these fractions. We calculate that only 1-7% contamination is present in the purified silicate mineral and whole rock fractions, whereas the HCl leachates contain up to 86% terrestrial contamination. Despite the contamination, we are able to use the U-Pb data to determine the initial {sup 206}Pb/{sup 204}Pb of QUE 94201 (11.086 {+-} 0.008) and calculate the {mu} value …
Date: December 22, 2006
Creator: Gaffney, A M; Borg, L E & Connelly, J N
Object Type: Article
System: The UNT Digital Library
Atomic Force Microscope (AFM) measurements and analysis on Tinsley AIA-1000-003 primary substrate (open access)

Atomic Force Microscope (AFM) measurements and analysis on Tinsley AIA-1000-003 primary substrate

None
Date: February 22, 2006
Creator: Soufli, R; Baker, S L & Robinson, J C
Object Type: Report
System: The UNT Digital Library
ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment with LX-10 (open access)

ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment with LX-10

We performed a computational and experimental analysis of fast cookoff of LX-10 (94.7% HMX, 5.3% Viton A) confined in a 2 kbar steel tube with reinforced end caps. A Scaled-Thermal-Explosion-eXperiment (STEX) was completed in which three radiant heaters were used to heat the vessel until ignition, resulting in a moderately violent explosion after 20.4 minutes. Thermocouple measurements showed tube temperatures as high as 340 C at ignition and LX-10 surface temperatures as high as 279 C, which is near the melting point of HMX. Three micro-power radar systems were used to measure mean fragment velocities of 840 m/s. Photonics Doppler Velocimeters (PDVs) showed a rapid acceleration of fragments over 80 {micro}s. A one-dimensional ALE3D cookoff model at the vessel midplane was used to simulate the heating, thermal expansion, LX-10 decomposition composition, and closing of the gap between the HE (High Explosive) and vessel wall. Although the ALE3D simulation terminated before ignition, the model provided a good representation of heat transfer through the case and across the dynamic gap to the explosive.
Date: November 22, 2006
Creator: McClelland, M. A.; Maienschein, J. L.; Howard, W. M. & Dehaven, M. R.
Object Type: Article
System: The UNT Digital Library