Bulletin of the American Physical Society
19th Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 60, Number 8
Sunday–Friday, June 14–19, 2015; Tampa, Florida
Session W1: Poster Session II (17:30 - 19:30) |
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Chair: Marcia Cooper, Sandia National Laboratories, Jeremy Danielson, Los Alamos National Laboratory Room: Grand ABCD |
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W1.00001: DETONATION AND SHOCK INDUCED CHEMISTRY |
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W1.00002: Magnetohydrodynamic modelling of exploding foil initiators William Neal Magnetohydrodynamic (MHD) codes are currently being developed, and used, to predict the behaviour of electrically-driven flyer-plates. These codes are of particular interest to the design of exploding foil initiator (EFI) detonators but there is a distinct lack of comparison with high-fidelity experimental data. This study aims to compare a MHD code with a collection of temporally and spatially resolved diagnostics including PDV, dual-axis imaging and streak imaging. The results show the code's excellent representation of the flyer-plate launch and highlight features within the experiment that the model fails to capture. [Preview Abstract] |
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W1.00003: Piezo-Electric Hypothesis for Hot Spot Formation Leading to Detonation D.S. Montgomery, M.J. Cawkwell, K.J. Ramos The impact to detonation sequence has been a long standing mystery in high explosives (HE). It is widely recognized that detonation begins in spatially-localized ``hot spots'' where chemistry initiates, but the physical mechanisms leading to hot spot formation are unknown. Here we revisit an old hypothesis, first suggested by Maycock and Grabenstein [1], that piezo-electric effects may be the cause of hot spot formation since most solid HE materials are observed to be highly piezo-electric. In this scenario, shock-induced pressure leads to electric fields of 100's MV/m, sufficient for dielectric breakdown and breaking chemical bonds, rather than via thermal effects. Extrapolation of statically measured piezo-electric coefficients for several HE materials suggests that shock pressures $>$ 100-kbar might lead to field strengths $>$ 100 - 1000 MV/m, but no definitive experimental proof has been obtained to support this. Here we discuss possible experiments to test this hypothesis by measuring the electric field in dynamic HE experiments correlated with hot spot formation. \\[4pt] [1] J.N. Maycock, D.E. Grabenstein, Science \textbf{152}, 508 (1966). [Preview Abstract] |
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W1.00004: ABSTRACT MOVED TO C3.00003 |
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W1.00005: Mechanochemistry for Shock Wave Energy Dissipation William Shaw, Yi Ren, Zhi Su, Jeffrey Moore, Kenneth Suslick, Dana Dlott Using our laser-driven flyer-plate apparatus we have developed a technique for detecting mechanically driven chemical reactions that attenuate shock waves. In these experiments 75 $\mu$m laser-driven flyer-plates travel at speeds of up to 2.8 km/s. Photonic Doppler velocimetry is used to monitor both the flight speed and the motions of an embedded mirror behind the sample on the supporting substrate. Since the Hugoniot of the substrate is known, mirror motions can be converted into the transmitted shock wave flux and fluence through a sample. Flux shows the shock profile whereas fluence represents the total energy transferred per unit area, and both are measured as a function of sample thickness. Targets materials are micrograms of carefully engineered organic and inorganic compounds selected for their potential to undergo negative volume, endothermic reactions. In situ fluorescence measurements and a suite of post mortem analytical methods are used to detect molecular chemical reactions that occur due to impact. [Preview Abstract] |
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W1.00006: Detonation Performance Testing of LX-19 Samuel Vincent, Tariq Aslam, Scott Jackson CL-20 was developed at the Naval Surface Weapons Center at China Lake, CA in the mid 80's. Being less sensitive than PETN, but considerably more powerful than HMX, it is the highest energy and density compound known among organic chemicals. LX-19 was developed at LLNL in the early 90's. It is a high-energy plastic bonded explosive, composed of 95.8 wt\% CL-20 and 4.2 wt\% Estane binder, and is similar to LX-14 (composed of HMX and Estane), but with greater sensitivity characteristics with use of the more energetic CL-20 explosive. We report detonation performance results for unconfined cylindrical rate sticks of LX-19. The experimental diameter effects are shown, along with detonation front shapes, and reaction zone profiles for different test diameters. This data is critical for calibration to Detonation Shock Dynamics (DSD). [Preview Abstract] |
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W1.00007: Detonation Performance Measurements of Cyclotol 75/25 Timothy Kuiper, Eric Anderson, Mark Short, Scott Jackson Cyclotol is a melt-castable high explosive composed of RDX and TNT. The term Cyclotol may apply to other mixtures of these two components, but for the present work, experiments were conducted using 75 wt\% RDX and 25 wt\% TNT. Diameter-effect data for Cyclotol 75/25 is available from prior work. In the current effort, we report front-shape measurements that are crucial for calibration of the Detonation Shock Dynamics (DSD) based programmed burn models as well as for reactive burn models. Diameter-effect measurements are also obtained and compared to prior work. In addition, wall-velocity profiles from a cylinder test are reported along with product isentropes computed from the velocity profiles. [Preview Abstract] |
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W1.00008: ENERGETIC AND REACTIVE MATERIALS |
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W1.00009: ABSTRACT MOVED TO S2.00005 |
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W1.00010: Characterization of Diacetone Diperoxide (DADP) Patrick Bowden, Daniel Preston, Bryce Tappan, Virginia Manner To date, diacetone diperoxide (DADP) has been significantly less studied than its well-known counterpart, triacetone triperoxide (TATP). Much of this disparity in the literature is due to the harsher conditions/multi-step syntheses required to obtain DADP leading to much lower evidence of frequency of use. Because of this, DADP is often misrepresented as being more dangerous (i.e. more sensitive and less stable) than TATP. This paper discusses the synthesis and characterization (sensitivity, thermal stability, etc.) of DADP with respect to other energetic organic peroxides (TATP, HMTD and MEKP); investigating differences in polymorphism, crystal habit and effects of aging and processing differences will be discussed. Additionally, deflagation-to-detonation transition (DDT) of organic peroxides will be presented. [Preview Abstract] |
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W1.00011: Thermal safety characterization and explosion violence of energetic materials Peter Hsu, Gary Hust, Philip Pagoria, Larry Fried Some energetic materials could thermally explode at fairly low temperatures (\textless 100 C) and the violence from thermal explosion may cause a significant damage. Thus understanding the response of energetic material to thermal events is very important for the storage and handling of energetic materials. Over the last few decades, there has been considerable research effort on the thermal decomposition and thermal explosion violence of energetic materials at elevated temperatures in different sample geometries and confinements. Among them, the ODTX system is an interesting option due to its sample requirement and easiness for data modeling. It has been used since 1970s for cook-off study at LLNL. It generates 3 technical data: (1) lowest temperature at which thermal explosion would occur (threshold temperature, T$_{\mathrm{il}})$, (2) times to thermal explosion at temperature above T$_{\mathrm{il}}$, for the calculation of activation energy and frequency factor; and (3) thermal explosion violence. In this paper, we will present some recent ODTX experimental data of several new energetic materials as well as gas pressure data at elevated temperature. [Preview Abstract] |
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W1.00012: Studies of thermal dissolution of RDX in TNT melt Natalya Suvorova, Virginia Hamilton, David Oschwald, Laura Smilowitz, Bryan Henson The thermal response of energetic materials is studied due to its importance in issues of material safety and surety. Secondary high explosives which melt before they thermally decompose present challenging systems to model due to the addition of material flow. Composition B is a particularly challenging system due to its multiphase nature with a low melt component (TNT) and a high melt component (RDX). The dissolution of RDX crystals in molten TNT at the temperature below RDX melting point has been investigated using hot stage microscopy and Raman spectroscopy. In this paper, we will present data on the dissolution rate of RDX crystals in molten TNT as a function of temperature above the TNT melt. [Preview Abstract] |
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W1.00013: EQUATIONS OF STATE |
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W1.00014: High pressure phase diagram of MgO Martin French, Daniel Cebulla, Ronald Redmer In order to improve the understanding of the interior of super-Earths (planets in the range of 1-10 Earth masses) and other exoplanets, ab inito calculations for the planetary materials and the equation of state (EOS) and phase diagram of planetary materials are needed. A typical representative is MgO, which is an abundant material in the Earth's mantle and is also expected to be important for the mantle of exoplanets as well as for the rocky cores of gas giants such as Jupiter. Using ab initio molecular dynamic simulations, we have determined the phase diagram for MgO up to 20000 K and 1.5 TPa. In particular, the transition from the solid to the molten salt has been studied using diffusion analyses and pair distribution functions. The transition from the B1 to the B2 structure in solid MgO is determined by calculating the respective free enthalpies. The phase diagram of MgO is constructed based on accurate EOS data. We compare with results from (decaying) shock and ramp compression experiments and theoretical calculations for the B1-B2 and the liquid-solid transition line [1, 2, 3].\\[4pt] [1] R.S. McWilliams et al., Science, {\bf 338}, 1330 (2012).\\[0pt] [2] F. Coppari et al., Nat. Geoscience, {\bf 6}, 926 (2013).\\[0pt] [3] D. Cebulla et al, PRB, {\bf 89}, 134107 (2014) [Preview Abstract] |
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W1.00015: Pressure dependence of Hexanitrostilbene Raman/ electronic absorption spectra to validate DFT EOS Darcie Farrow, Kathleen Alam, Laura Martin, Hongyou Fan, Jeffrey Kay, Ryan Wixom Due to its thermal stability and low vapor pressure, Hexanitrostilbene (HNS) is often used in high-temperature or vacuum applications as a detonator explosive or in mild detonating fuse. Toward improving the accuracy of the equation of state used in hydrodynamic simulations of the performance of HNS, we have measured the Raman and electronic absorption spectra of this material under static pressure in a diamond anvil cell. Density functional theory calculations were used to simulate the pressure dependence of the Raman/Electronic spectra along the Hugoniot and 300K isotherm for comparison and to aid in interpreting the data. We will discuss changes in the electronic structure of HNS under pressure, validation of a DFT predicted equation of state (EOS), and using this data as a basis for understanding future pulsed Raman measurements on dynamically compressed HNS samples. [Preview Abstract] |
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W1.00016: AM363 martensitic Stainless Steel: a multiphase equation of state Giulia De Lorenzi-Venneri, Scott Crockett A multiphase equation of state for stainless steel AM363 has been developed. Three phases are constructed separately: the low pressure martensitic phase, the austenitic phase and the liquid. Room temperature data and the explicit introduction of a magnetic contribution to the free energy determine the martensitic phase, while shock Hugoniot data is used to determine the austenitic phase and the phase boundaries. More experimental data would be useful to better characterize the liquid. [Preview Abstract] |
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W1.00017: An equation of state consistent with the Hugoniot abnormality A.D. Resnyansky Development of Equations of State (EOSs) for description of the Hugoniot abnormality in porous materials is still of interest to physicists. The Mie-Gruneisen EOS is usually a basis of such new EOSs. The present development also follows the Mie-Gruneisen EOS approach, however, complemented with the two-phase consideration of a material analyzed, which is employing simple EOSs for each of the two phases. The Hugoniot abnormality has previously been analyzed with a two-phase material model implemented in the CTH hydrocode. The analysis has shown that the inter-phase equilibrium is an important factor for manifestation of the abnormality in highly porous materials. In particular, the necessary condition was found to be the pressure and temperature equilibrium between the gaseous and condensed phases. The present work demonstrates that the abnormality in the condition of the equilibrium is routinely achieved at a sufficiently high concentration of the gaseous phase when employing the Mie-Gruneisen EOSs with constant Gruneisen parameters for the gaseous and condensed constituents. However, the effective Gruneisen parameter for the two-phase mixture cannot be routinely determined. The high-pressure sections of the Hugoniot curves obtained with the present EOS correlate with experimental data available in literature. [Preview Abstract] |
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W1.00018: Silicon Nitride Equation of State Pazhayannur Swaminathan, Robert Brown This report presents the development a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si$_{3}$N$_{4})$. Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal $\alpha$-Si$_{3}$N$_{4}$, hexagonal $\beta$-Si$_{3}$N$_{4}$, and the cubic spinel c-Si$_{3}$N$_{4}$. Decomposition at about 1900 $^{\circ}$C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products and then combined with the single component solid models to study the global phase diagram. [Preview Abstract] |
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W1.00019: EXPERIMENTAL DEVELOPMENTS |
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W1.00020: On a novel graded areal density solution to facilitate ramp wave generation in plate-impact studies Jonathan Painter, Brianna Fitzmaurice, Michael Goff, Gareth Appleby-Thomas, David Wood, Tom Pinto Building on a substantial body of work on functionally graded materials in the literature, it has been previously shown that the use of graded areal density impactors, in conjunction with buffer materials, allows generation of ramp-wave loading profiles in impacted targets. Such off-principle-Hugoniot loading paths are of particular interest where control of one or more state variables (e.g. temperature) is desirable during the loading event. Previous attempts to produce suitable graded areal density impactors have focused on rapid protoyping techniques such as 3D printing. While suitable for small-scale production of impactors, such technologies are relatively immature. Instead, here a novel approach to creating graded areal density structures -- TWI Ltd's novel surface modification process, SurfiSculpt$^{\mathrm{\mbox{\textregistered }}}$, with a nominal surface spike distribution of 1.5 per mm$^{\mathrm{2}}$, has been employed to produce the required impactors. Initial experimental results are presented highlighting the potential of this experimental approach; further, these results -- combined with basic hydrocode simulations -- are used to postulated idealised structures which would allow useful loading paths such as the Adiabat to be readily accessed. [Preview Abstract] |
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W1.00021: Minimizing masses in explosively driven two-shockwave physics applications William Buttler, Frank Cherne, Michael Furlanetto, Jeremy Payton, Joseph Stone, Leonard Tabaka, Samuel Vincent We have experimentally investigated different two-shockwave high-explosives (HE) physics package designs to maximize the variability of the second shockwave peak stress, while minimizing the total HE load of the physics tool. A critical requirement is to also have a large radial diameter of the second shockwave to maintain its value as an HE driven two-shockwave drive. We have previously shown that we could vary the peak-stress of the second-shockwave with a 76 mm diameter HE lens driving different composite boosters of PBX 9501 and TNT. Here we report on our results with a 56- and 50-mm diameter HE lens driving Baritol. The results indicate that the 56-mm diameter HE lens works well, as does the Baritol, giving total HE loads of about 250 mg TNT equivalent explosives. [Preview Abstract] |
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W1.00022: Reduction of ejecta from asperities on a metal surface upon shock breakout William Georges, Jason Loiseau, Andrew Higgins, Troy Tyler, Joerg Zimmermann Ejecta can be produced when a shock breaks out of a metallic surface with imperfections. The amount of material ejected depends on the strength of the shock and the surface roughness. This work focuses on the differences between square wave and Taylor wave loading, as well as examining techniques to reduce the amount of ejecta produced. In the case of square wave loading, an explosively driven flyer was launched onto an aluminum target featuring machined V-grooves on its surface. The velocity of ejecta launched into vacuum was monitored by photon Doppler velocimetry (PDV). The Taylor wave was produced by detonating a high explosive next to the aluminum target and the ejecta again monitored with PDV. To attempt to suppress the ejecta, the shock breakout pressure was reduced by the addition of an air gap. A nearly shock-less compression was also achieved by evacuating the space between the explosive and the target. [Preview Abstract] |
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W1.00023: Ejecta particle size measurements for shocked Sn targets based on the Mie scattering technique Todd Haines, Shabnam Monfared, Martin Schauer Los Alamos National Laboratory is actively engaged in material failure research. The goal of these studies is to support development of hydrodynamic models, where an important failure mechanism of explosively shocked metals causes mass ejection from perturbations on the shocked surface. While we have had success developing ejecta mass and velocity models, better data on the size and velocity distributions of the ejected mass is needed. To support size measurements we are developing an affordable technique based on the scattering of a monochromatic light using inexpensive fiber optics and a single diode laser. In this presentation, we will discuss static test experiments on polystyrene particles of known size designed to test the precision and reproducibility of the method. We will also present results from experiments performed on the 0.99995 purity Sn targets shocked to loading pressure of about 27 GPa. Results from the fielded dynamic experiments based on the transmitted and scattered intensities from ejecta clouds are in reasonable agreement and yield estimated average particle sizes in the range of 1-5 $\mu $m. [Preview Abstract] |
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W1.00024: ABSTRACT WITHDRAWN |
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W1.00025: Gas loading system for LANL two-stage gas guns Lee Gibson, Brian Bartram, Dana Dattelbaum, John Lang, John Morris A novel gas loading system was designed for the specific application of remotely loading high purity gases into targets for gas-gun driven plate impact experiments. The high purity gases are loaded into well-defined target configurations to obtain Hugoniot states in the gas phase at greater than ambient pressures. The small volume of the gas samples is challenging, as slight changing in the ambient temperature result in measurable pressure changes. Therefore, the ability to load a gas gun target and continually monitor the sample pressure prior to firing provides the most stable and reliable target fielding approach. We present the design and evaluation of a gas loading system built for the LANL 50 mm bore two-stage light gas gun. Targets for the gun are made of 6061 Al or OFHC Cu, and assembled to form a gas containment cell with a volume of approximately 1.38 cc. The compatibility of materials was a major consideration in the design of the system, particularly for its use with corrosive gases. Piping and valves are stainless steel with wetted seals made from Kalrez and Teflon. Preliminary testing was completed to ensure proper flow rate and that the proper safety controls were in place. The system has been used to successfully load Ar, Kr, Xe, and anhydrous ammonia with purities of up to 99.999 percent. The design of the system, and example data from the plate impact experiments will be shown. LA-UR-15-20521 [Preview Abstract] |
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W1.00026: Design considerations for diffraction measurements in the TPa regime J.R. Rygg, J. Eggert, R. Smith, A. Jenei, D. Fratanduono, D. Braun, J. McNaney, G. Collins, T. Arsenlis Diffraction measurements from a variety of materials compressed above 1 TPa has been demonstrated on the OMEGA and NIF facilities. Thin samples of the material are sandwiched between diamond slabs and ramp-compressed using shaped laser pulses. X-ray diffraction is recorded by flashing an short (1 ns) x-ray source at the time of peak compression, and pressure is determined through concomitant VISAR measurements. A selection of considerations regarding the experimental design and data analysis are herein presented. [Preview Abstract] |
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W1.00027: Synchrotron hard X-ray imaging of shock-compressed metal powders Michael E. Rutherford, David J. Chapman, Mark A. Collinson, David R. Jones, Jasmina Music, Samuel J.P. Stafford, Gareth R. Tear, Thomas G. White, John B.R. Winters, Michael Drakopoulos, Daniel E. Eakins This poster will present the application of a new, high-energy (50 to 250 keV) synchrotron X-ray radiography technique [1] to the study of shock-compressed granular materials. Following plate-impact loading, transmission radiography was used to quantitatively observe the compaction and release processes in a range of high-Z metal powders (e.g. Fe, Ni, Cu). By comparing the predictions of 3D numerical models initialized from X-ray tomograms--captured prior to loading--with experimental results, this research represents a new approach to refining mesoscopic compaction models. \\[4pt] [1] D. E. Eakins and D. J. Chapman, Review of Scientific Instruments 85, 123708 (2014). [Preview Abstract] |
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W1.00028: Mass estimation of shaped charge jets from x-ray shadow graph with new calibration curve method Fumikazu Saito, Hiroaki Kishimura, Akira Kumakura, Shun Sakai In order to assess the penetration capability of the Al and Cu metal jets against a bumper structure (such as Al plate and /or Al block), we measured the initial formation process of the metal jets generated from conical shaped charge device. The shaped charge device configurations employed in the experimental and numerical investigations have conical aluminum (and cupper) liner and steel casing with PBX explosive charge. The profile and velocity of the jets are measured with flash x-ray and x-ray film system. The mass of the jet tip are estimated from x-ray images by a calibration curve method proposed by our group. Al targets are used to evaluate a penetration performance of the jets. Additionally, we have simulated the initial formation process of the shaped charge jets with Autodyne-2D hydrodynamic code, which proposed important data to compare the experimental one. [Preview Abstract] |
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W1.00029: A novel setup for time-resolved X-ray diffraction for gas gun experiments Camille Chauvin, Fr\'ed\'eric Zucchini, Thierry D'Almeida, Jacques Petit Polymorphic phase transitions in metals have been investigated for a long time under dynamic loadings through usual dynamic compression diagnostics such as velocity and temperature measurements. Such measurements were valuable for revealing the key role of kinetic effects in most phase transition mechanisms. However, the information extracted was mostly macroscopic. Obtaining direct insight about the crystallographic structure under dynamic loadings is critical for understanding mechanisms governing shock-induced structural changes. For example, in order to evidence a mixture phase or to determine the time scale of a transition, structural information may be extremely valuable. Over the last 20 years a significant number of X-ray diffraction experiments were carried under dynamic loading, either using laboratory X-ray sources or synchrotron radiation. We are developing a novel experimental setup based on a compact High Pulsed Power generator capable of producing intense X radiation through X-pinch. This source is specifically designed for time-resolved X-ray diffraction in Bragg geometry on gas gun experiments. Promising preliminary data obtained under static conditions are presented. [Preview Abstract] |
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W1.00030: A novel tomographic technique for energetic materials C.C. Stennett, S.E. Stennett, Christoph Rau, S.A. McDonald, N.K. Bourne, P.J. withers It is a pressing matter to understand microstructural details within polymer matrix composites with energetic filler particles within. The generation of three-dimensional microstructure, using a noninvasive method of high resolution will advance knowledge in a range of fields. A range of inert composites analogous to plastic bonded explosives (PBXs) with crystalline and amorphous phases have been studied, and X-ray microtomography for microstructural investigation on the Diamond-Manchester I13 beamline. One of the compositions had crystal densities close to the binder and the other very different so that particles could be resolved easily in the one case and with great difficulty, even with phase contrast techniques in the other. Improvements int eh imaging made it possible to adequately define the bulk morphology, to determine the geometry of defects that might lead to sites for accidental ignition within the material and to demonstrate a direct linkage into the finite element predictions of mechanical response. Once demonstrated, the damage in a real loaded HE was assessed and quantified. [Preview Abstract] |
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W1.00031: Thor: Modeling of a Megabar Class Pulsed Power Accelerator T.A. Haill, D.B. Reisman, B.S. Stoltzfus, K.N. Austin, W.A. Stygar, J.L. Brown, J.-P. Davis, E.M. Waisman Thor is a compact, economical machine to drive megabar-class shockless compression material physics experiments and multi-mega-ampere HEDP experiments for the physics community. It is capable of driving peak currents up to 7 MA with rise times of 200-500 ns, resulting in material pressures between 1 to 5 Mbar depending upon the load design, and incorporates a pulse tailoring capability required to maintain shockless loading of many materials. Thor is modular in nature with 200 capacitive bricks triggered in groups by independent, de-coupled switches. The current pulse at the load is a simple linear combination of the 200 time-shifted basis pulses. This enables a variety of experiments including shockless compression experiments using smooth ramped pulses, shock-ramp compression experiments using tailored pulses, and strength measurement experiments using flat top pulses. This paper overviews the Thor design and describes an equivalent circuit model of the machine that drives MHD simulations of the load region. 3D ALEGRA MHD simulations explore topics such as the uniformity of the magnetic field along the stripline load and the design modifications to improve uniformity. Optimized current drives and simulations of the aforementioned applications are also presented. [Preview Abstract] |
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W1.00032: ABSTRACT WITHDRAWN |
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W1.00033: Transient x-ray diffraction with simultaneous imaging under high strain-rate loading Duan Fan, Sheng-Nian Luo Real time, in situ, multiframe, diffraction, and imaging measurements on bulk samples under high and ultrahigh strain-rate loading are highly desirable for micro- and mesoscale sciences. We present an experimental demonstration of multiframe transient x-ray diffraction (TXD) along with simultaneous imaging under high strain-rate loading at the Advanced Photon Source beamline 32ID. The feasibility study utilizes high strain-rate Hopkinson bar loading on a Mg alloy. The exposure time in TXD is 2--3 $\mu $s, and the frame interval is 26.7--62.5 $\mu $s. Various dynamic deformation mechanisms are revealed by TXD, including lattice expansion or compression, crystal plasticity, grain or lattice rotation, and likely grain refinement, as well as considerable anisotropy in deformation. Dynamic strain fields are mapped via x-ray digital image correlation, and are consistent with the diffraction measurements and loading histories. [Preview Abstract] |
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W1.00034: FIRST PRINCIPLES AND MOLECULAR DYNAMICS |
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W1.00035: Molecular Dynamics Simulations of an Idealized Shock Tube: N$_{2}$ in Ar Bath Driven by He Ezekiel Ashe Piskulich, Thomas D. Sewell, Donald L. Thompson The dynamics of 10{\%} N$_{2}$ in Ar initially at 298 K in an idealized shock tube driven by He was studied using molecular dynamics. The simulations were performed using the Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code. Nitrogen was modeled as a Morse oscillator and non-covalent interactions were approximated by the Buckingham exponential-6 pair potential. The initial pressures in the He driver gas and the driven N$_{2}$/Ar gas were 1000 atm and 20 atm, respectively. Microcanonical trajectories were followed for 2 ns following release of the driver gas. Results for excitation and subsequent relaxation of the N$_{2}$, as well as properties of the gas during the simulations, will be reported. [Preview Abstract] |
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W1.00036: GEOPHYSICS AND PLANETARY SCIENCE |
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W1.00037: Measurements of band gap structure in diamond compressed to 370 GPa Eliseo Gamboa, Luke Fletcher, Hae-Ja Lee, Ulf Zastrau, Maxence Gauthier, Dirk Gericke, Jan Vorberger, Eduardo Granados, Phillip Heimann, Jerome Hastings, Siegfried Glenzer We present the first measurements of the electronic structure of dynamically compressed diamond demonstrating a widening of the band gap to pressures of up to 370 $\pm$ 25 GPa. The 8 keV free electron laser x-ray beam from the Linac Coherently Light Source (LCLS) has been focussed onto a diamond foil compressed by two counter-propagating laser pulses to densities of up to 5.3 g/cm$^{3}$ and temperatures of up to 3000 $\pm$ 400 K. The x-ray pulse excites a collective interband transition of the valence electrons, leading to a plasmon-like loss. We find good agreement with the observed plasmon shift by including the pressure dependence of the band gap as determined from density functional theory simulations. [Preview Abstract] |
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W1.00038: Ray Tracing to Predict Optical Behaviour of Shock Compressed Dielectrics Gareth R. Tear, William G. Proud In order to investigate the optical response of dielectric materials under shock compression, a characteristics model has been combined with a three dimensional optical ray tracing model. A general biaxial optical model is used along with a first order photoelastic model which couples the characteristics component to the optical component. This optical model is three dimensional and as such can be used to investigate small deviations from the perfect one dimensional shock wave which is typically assumed in plate impact experiments. A detailed description of the model will be presented, and comparison to available literature as well as recent experiments on the optical behaviour of shock compressed a-cut calcite and a-cut sapphire. The authors would like to thank Dr D E Eakins and Dr D J Chapman for fruitful discussions. [Preview Abstract] |
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W1.00039: Investigating Metallization in Shock-Compressed Alkali Halides Matthew Diamond Laser-shock compression on four alkali halides has been used to probe the transition from insulating to metallic states, a high-pressure transition in chemical bonding that has fundamental implications for planetary formation and structure. Collectively, pressures up to 450 GPa were explored across a total of fourteen single-crystal samples of CsI, CsBr, KBr and NaCl. Velocity interferometry was used to record shock velocities and reflectivities at 532 nm during decaying shock compression. The data show up to three-fold increases in density as well as significant increases in optical reflectivity in response to high pressures and temperatures. Ionic salts are simple model systems amenable to first-principles theory and serve as analog materials for predicting whether specific chemical constituents can reside in the rocky mantles or metallic cores of planets. A key objective is to disentangle the complementary roles of temperature and compression in transforming ionic into metallic bonding. Furthermore, at high pressures CsI becomes analogous to Xe: they are isoelectronic and follow matching equations of state. Therefore, studies on CsI can inform understanding of noble-gas geochemistry at conditions deep inside planets. [Preview Abstract] |
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W1.00040: Birch's Law for high-pressure metals and ionic solids: Sound velocity data comparison between shock wave experiments and recent diamond anvil cell experiments David Boness, Lucas Ware Sound velocity-density systematics has long been a fruitful way to take shock wave measurements on elements, alloys, oxides, rocks, and other materials, and allow reasonable extrapolation to densities found deep in the Earth. Recent detection of super-Earths has expanded interest in terrestrial planetary interiors to an even greater range of materials and pressures. Recent published DAC experimental measurements of sound velocities in iron and iron alloys, relevant to planetary cores, are inconsistent with each other with regard to the validity of Birch's Law, a linear relation between sound velocity and density. We examine the range of validity of Birch's Law for several shocked metallic elements, including iron, and shocked ionic solids and make comparisons to the recent DAC data. [Preview Abstract] |
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W1.00041: GRAIN SCALE TO CONTINUUM MODELING |
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W1.00042: Development of numerical model to investigate the laser driven shock waves from aluminum target into ambient air at atmospheric pressure and its comparison with experiment Prem Kiran Paturi, Sai Shiva Sakaraboina, Leela Chelikani, Venkata Ramana Ikkurthi, Sijoy C.D., Shashank Chaturvedi A one-dimensional, three-temperature (electron, ion and thermal radiation) numerical model to study the laser induced shock wave (LISW) propagation from aluminum target in ambient air at atmospheric pressure is developed. The hydrodynamic equations of mass, momentum and energy are solved by using an implicit scheme in Lagrangian form. The model considers the laser absorption to take place via inverse-bremsstrahlung due to electron-ion (e-i) process. The flux limited electron thermal energy transport and e-i thermal energy relaxation equations are solved implicitly. The experimental characterization of spatio-temporal evolution of the LISW in air generated by focusing a second harmonic (532 nm, 7ns) of Nd:YAG laser on to surface of Al is performed using shadowgraphy technique with a temporal resolution of 1.5 ns. The radius of SW (2 - 5 mm) and its pressure (40 -- 80 MPa) observed in the experiments over 0.2 $\mu$s-10 $\mu$s time scales were comparable with the numerical results for laser intensities ranging from 2.0 $\times$ 10$^{10}$ to 1.4 $\times$ 10$^{11}$ W/cm$^{2}$. [Preview Abstract] |
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W1.00043: HIGH ENERGY PHYSICS/WARM DENSE MATTER |
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W1.00044: Thermal conductivity measurements of proton-heated warm dense matter A. McKelvey, A. Fernandez-Panella, R. Hua, J. Kim, J. King, H. Sio, C. McGuffey, G.E. Kemp, R.R. Freeman, F.N. Beg, R. Shepherd, Y. Ping Accurate knowledge of conductivity characteristics in the strongly coupled plasma regime is extremely important for ICF processes such as the onset of hydrodynamic instabilities, thermonuclear burn propagation waves, shell mixing, and efficient x-ray conversion of indirect drive schemes. Recently, an experiment was performed on the Titan laser platform at the Jupiter Laser Facility to measure the thermal conductivity of proton-heated warm dense matter. In the experiment, proton beams generated via target normal sheath acceleration were used to heat bi-layer targets with high-Z front layers and lower-Z back layers. The stopping power of a material is approximately proportional to Z$^2$ so a sharp temperature gradient is established between the two materials. The subsequent thermal conduction from the higher-Z material to the lower-Z was measured with time resolved streaked optical pyrometry (SOP) and Fourier domain interferometry (FDI) of the rear surface. Results will be used to compare predictions from the thermal conduction equation and the Wiedemann-Franz Law in the warm dense matter regime. Data from the time resolved diagnostics for Au/Al and Au/C Targets of 20-200 nm thickness will be presented. [Preview Abstract] |
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W1.00045: INELASTIC DEFORMATIONS, FRACTURE AND SPALL |
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W1.00046: The Influence of Hydrogen on the Microstructure and Dynamic Strength of Lean Duplex Stainless Steel Ravit Silverstein, Benny Glam, Dan Eliezer, Daniel Moreno, Shalom Eliezer In this research the dynamic strength of lean duplex stainless steel (LDS) with and without hydrogen was investigated. The LDS was chosen since it has a mixed structure of ferrite (BCC) and austenite (FCC) which allows an attractive combination of high strength and plasticity. Data collection was performed by VISAR and metallurgical analysis by post mortem observation. In addition, a thermal desorption process (TDS) was carried out in order to observe the influence of hydrogen charging on LDS crystal structure and to determine the hydrogen trapping mechanism before and after the plate impact experiments. Several assessments can be made based on the results of this study. TDS analysis revealed that even after hydrogen desorption, some hydrogen remained trapped in the austenitic phase causing a small lattice expansion. After impact, a brittle spall mechanism was seen, which occurred through crack progression along both phases grain boundaries. It was found that even small hydrogen content affects the dynamic strength of LDS. The relation between the microstructure and the dynamic strength of the LDS in the presence of hydrogen will be discussed. This work was supported by the Pazi foundation. [Preview Abstract] |
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W1.00047: Film-substrate hydrodynamic interaction initiated by femtosecond laser irradiation Viktor Khokhlov, Nail Inogamov, Vasily Zhakhovsky, Denis Ilnitsky, Kirill Migdal, Vadim Shepelev Action of an ultrashort single laser pulse onto a thin metal film is considered. Disruption of a plane freestanding film quickly heated by laser is the simplest model of laser spallation. There is a sharp spallation (ablation) threshold $F_a$ dividing dynamics of freestanding film to two regimes: below or above the threshold $F_a.$ Problem of significant importance is: how this picture will change when a film is deposited onto substrate? We have solved this problem. It is found that there are two thresholds $F_s < F_a$ and three regimes of motion relative to the case of freestanding film. For $0 < F < F_s$ film oscillates remaining on substrate. Oscillations decay in time due to irradiation of sonic waves into substrate. For $F_s < F < F_a$ the film delaminates from substrate because negative pressure propagating with acoustic wave comes to a film-substrate contact and overcomes cohesion strength of a contact. In the third regime $F_a < F$ there is disruption of a film before the instant when negative pressure separates metal and dielectric substrate at a contact. [Preview Abstract] |
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W1.00048: Fracture response of several metals to fast heating of samples by intensive X-ray radiation Vladimir Golubev Results on studying the fracture response of metals samples in the form of thin disks to fast heating by the intensive pulse of X-ray radiation of a complete spectrum are presented in the paper. The samples of such metals as iron, copper, AMg6 aluminum, VT14 titanium, molybdenum, tungsten, cadmium, lead and zinc were tested. The samples were fixed in the special cartridges that were placed at such distances from the X-ray irradiator where the energy fluxes were 1.38, 0.90 and 0.29 kJ/cm$^{\mathrm{2}}$. The irradiating X-ray pulse was about 2 ns in duration. After testing, the depth of material ablation from a sample front surface and the degree and character of its spall damage were determined. The method of metallographic analysis was used for these purposes. The spectrum data were used for the calculations of samples heating. Numerical calculations of thermomechanical and shock wave loading conditions were made with the use of the equation of state taking into account the process of evaporation. The calculated value of maximum negative pressure in the sample at the coordinate corresponding to the depth of ablation and formation of spallation zones or spall cracks was conventionally accepted as the material resistance to spall fracture in such conditions. The comparison of obtained results with the data on the fracture of examined materials in the conditions of fast heating by the X-ray pulse with a hard spectrum and by the high-current electron beam of an electron pulse generator was conducted. [Preview Abstract] |
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W1.00049: ABSTRACT WITHDRAWN |
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W1.00050: On the influence of texture on spall evolution in the HCP materials Ti64 and Zr James Shackel, Euan Wielewski, Paul Hazell, Jonathan Painter, David Rugg, David Wood, Gareth Appleby-Thomas Dynamic tensile failure (spall) is known to be a highly microstructure-dependant phenomena. In particular, spall is greatly influenced by the availability of plastic failure modes such as slip planes. Significant effort has been put into understanding spall in the common engineering BCC and FCC materials, however there is a relative paucity of data on such behaviour in the highly anisotropic HCP class of materials. Here the dynamic behaviour of two important HCP materials, Ti64 and Zr is investigated via plate-impact experiments as a function of target material texture, with the aim of enhancing understanding of this complex class of materials. [Preview Abstract] |
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W1.00051: Modelling Deformation and Texture Evolution in OFHC Copper at Large Strain and High Strain Rate Nicola Bonora, Gabriel Testa, Andrew Ruggiero, Gianluca Iannitti, Magnus H\"ornqvist, Nooshin Mortazavi In this work, a two-scale approach to simulate high rate deformation and texture evolution in OFHC copper is presented. The modified Rusinek-Klepaczko material model was used to simulate the response of the material at continuum scale accounting for different deformation mechanisms occurring over an extensive range of strain rate and temperature. Material model parameters were determined from characterization test (mainly uniaxial tests) results. Successively, the model was validated simulating material deformation in Taylor anvil impact, symmetric Taylor impact (rod-on-rod) and dynamic tensile extrusion (DTE) tests. Texture evolution, under different deformation paths was simulated using the crystal plasticity package CPFEM and results were compared with those obtained by EBSD analysis. The possibility to incorporate the effect of grain size evolution and fragmentation at continuum scale is discussed. [Preview Abstract] |
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W1.00052: MATERIALS STRENGTH |
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W1.00053: Estimating the Resistive Strength of Dense Particle Suspensions During Ballistic Penetration Oren Petel In the present study, data that has been collected on the ballistic penetration of several dense particle suspensions are examined using simple analytical penetration models. Through measurement of the incident and residual velocities of the projectile through the suspensions, an estimate of the effective measure of the resistive strength of these suspensions to penetration is made. The discussion of these results will focus on the influence of the choice of material of the suspended particles as well as their concentration within the suspensions on the strength estimates. This effective strength parameter will also be considered in contrast to previous measurements of material strength for the same mixtures that were taken from a series of plate impact experiments. The variation of this strength parameter as a function of the incident velocity of the projectile will be used to discuss the influence of the relative compressibility within the suspensions on the bulk response of the multiphase system during penetration. [Preview Abstract] |
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W1.00054: Change of shear modulus and yield stress with pressure and temperature Yehuda Partom It is well known that the shear modulus (G) and yield stress (Y) of metals increase with pressure (P) and decrease with temperature (T). Steinberg, in his popular compendium of dynamic material properties, assumes for Y/Y$_{0}$(P,T)$=$G/G$_{0}$(P,T) linear relations based on derivatives determined experimentally at ambient conditions. But recent tests of certain metals found, although with some scatter, that G(P) along the principal Hugoniot is higher than what follows from Steinberg's relations. Here we use a different approach to estimate G/G$_{0}$(P,T). As a first approximation we let G(P,T) follow from assuming a constant Poisson ($\nu )$ ratio, which leads to G/G$_{0}=$K/K$_{0}$, where K is the isentropic bulk modulus. With this assumption we compute the longitudinal sound speed of tantalum along its principal Hugoniot, and compare to recent measurements. There is slight disagreement, which we correct by assuming (second approximation) that Poisson's ratio increases with temperature to 0.5 at melting. We calibrate this increase to fit the data for tantalum along the Hugoniot, and get that Y/Y$_{0}=$G/G$_{0}=$K/K$_{0}$[1$+$a(T-T$_{0})$]. As K$=\rho $c$^{2}$ is always available in a hydrocode run, so are G/G$_{0}$ and Y/Y$_{0}$. [Preview Abstract] |
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W1.00055: ABSTRACT MOVED TO M1.00054 |
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W1.00056: Dynamic Strength Ceramic Nanocomposites Under Pulse Loading Evgeniya G. Skripnyak, Vladimir V. Skripnyak, Irina K. Vaganova, Vladimir A. Skripnyak Multi-scale computer simulation approach has been applied to research of strength of nanocomposites under dynamic loading. The influence of mesoscopic substructures on the dynamic strength of ceramic and hybrid nanocomposites, which can be formed using additive manufacturing were numerically investigated. At weak shock wave loadings the shear strength and the spall strength of ceramic and hybrid nanocomposites depends not only phase concentration and porosity, but size parameters of skeleton substructures. The influence of skeleton parameter on the shear strength and the spall strength of ceramic nanocomposites with the same concentration of phases decreases with increasing amplitude of the shock pulse of microsecond duration above the double amplitude of the Hugoniot elastic limit of nanocomposites. [Preview Abstract] |
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W1.00057: PARTICULATE, POROUS AND COMPOSITE MATERIAL |
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W1.00058: Dynamic response of laser ablative shock waves from coated and uncoated amorphous Boron nanoparticles Prem Kiran Paturi, Leela Chelikani, Venkateshwarlu Pinnoju, Pankaj Verma, Raja V Singh Nanoparticles (NP) improve the performance of solid rocket motors with increased burning rate and lower ignition threshold owing to their larger surface area. We present spatio-temporal evolution of laser ablative shock waves (LASWs) from compacted amorphous Boron (B) and Lithium Fluoride coated Boron (LiF-B) of 70-110nm sizes that were compacted to form pellets. Thickness of the LiF coating is 5.5 $\pm$ 1nm in LiF-B. Laser pulses from second harmonic of Nd:YAG laser (532nm, 7ns) are used to generate LASWs expanding in ambient air. The precise time of energy release from the pellets under extreme ablative pressures is studied using shadowgraphy with a temporal resolution of 1.5 ns. Different nature of the shock front (SF) following Sedov-Taylor theory, before and after detachment, indicated two specific time dependent stages of energy release. From the position of SF, velocity behind the SF, similar to that of exhaust velocity is measured. Specific impulse of 241 $\pm$ 5 and 201 $\pm$ 4 sec for LiF-B and B, respectively, at a delay of 0.8$\mu $s from shock inducing laser pulse makes them potential candidates for laser based micro thruster applications. [Preview Abstract] |
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W1.00059: Dynamic crack propagation through nanoporous media Thao Nguyen, Justin Wilkerson The deformation and failure of nanoporous metals may be considerably different than that of more traditional bulk porous metals. The length scales in traditional bulk porous metals are typically large enough for classic plasticity and buckling to be operative. However, the extremely small length scales associated with nanoporous metals may inhibit classic plasticity mechanisms. Here, we motivate an alternative nanovoid growth mechanism mediated by dislocation emission. Following an approach similar to Lubarda and co-workers, we make use of stability arguments applied to the analytic solutions of the elastic interactions of dislocations and voids to derive a simple stress-based criterion for emission activation. We then propose a dynamic nanovoid growth law that is motivated by the kinetics of dislocation emission. The resulting failure model is implemented into a commercial finite element software to simulate dynamic crack growth. The simulations reveal that crack propagation through a nanoporous media proceeds at somewhat faster velocities than through the more traditional bulk porous metal. [Preview Abstract] |
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W1.00060: Fluorescent probes for shock compression spectroscopy of microstructured materials James Christensen, Alexandr Banishev, Dana Dlott We are developing fluorescent probes to obtain time-resolved two-dimensional pressure maps of microstructured materials under shock compression. We have fabricated dye-doped silica nano- or micro-spheres which may be dispersed throughout a microstructured sample. Alternatively we can grow a thin layer of dye-doped silica on the surface of a larger grain. The microspheres were embedded in PMMA and shocked to 3--8.4 GPa using laser-driven flyer plates. The shocked emission had both a redshift and an intensity loss. It is easier in two dimensions to measure intensity changes rather than spectral shifts. When fluorescent dye was dispersed freely in PMMA, the intensity loss was much slower than the spectral shift. But by encapsulating the dye in silica, the emission became not only brighter but the intensity loss occurred on the same timescale as the redshift. Current research focuses on studies of the photophysical mechanism of dye response to shock and using this technique in granular media such as sand under shock compression. [Preview Abstract] |
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W1.00061: PHASE TRANSITIONS |
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W1.00062: ABSTRACT MOVED TO F4.00004 |
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W1.00063: Shock-compression on Eu$_{2}$O$_{3}$ doped pollucite phosphors Sho Hamada, Hiroaki Kishimura, Atsushi Aruga, Hitoshi Matsumoto Pollucite CsAlSi$_{2}$O$_{6}$ is a natural mineral belong to zeolite group formed with analcime, and general formula is following: (Cs,Na)$_{16}$Al$_{16}$Si$_{32}$O$_{96}$$\cdot$n(H$_{2}$O). The crystal structure of pure CsAlSi$_{2}$O$_{6}$ is cubic(Ia-3d) and unit cell is 136645 nm Pollucite is stable stone yielding on the surface of the Earth since ancient times and is used to as a raw material of Cs element. Eu$_{2}$O$_{3}$-doped pollucite phosphors are efficient white phosphor for Application of deep-UV -light emitting diode (LED). Phosphors were prepared by solid-state reaction. 1 mol{\%} Eu$_{2}$O$_{3}$-doped and 3 mol{\%} Eu$_{2}$O$_{3}$-doped pollucites were prepared. Shock-recovery experiments were conducted involving the impact of a flyer plate accelerated by a single-stage powder-propellant gun. The recovered samples were characterized by X-ray diffraction (XRD) analysis and photoluminescence (PL) spectroscopy. The XRD and PL results of samples shocked at pressures of 22 GPa~indicated that dissolution and amorphous-to-crystalline transformation occurred. In addition, emission peak wavelength of 3 mol{\%} Eu$_{2}$O$_{3}$-doped sample shift 20 nm(520$\to $500 nm). As a result, it is considered that Eu$^{2+}$ moved in the crystalline by shock-compression. [Preview Abstract] |
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W1.00064: SOFT MATTER |
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W1.00065: Characterization of energetic and non-energetic polymers for laser ablation propulsion applications Prem Kiran Paturi, Leela Chelikani, Narasimha Rao Billa, Nagaraju Guthikonda, Tushar Jana Energetic Polymers, considered to be cleaner, environmental friendly materials are one of the primary candidates for future plasma thrusters. For e.g., energetic hydroxyl terminated polybutadiene (HTPB) is being used as a binder for high-performance composite propellants. Understanding the conversion of optical energy to kinetic energy is essential in evaluating these materials as thrusters. Spatio-temporal evolution of laser ablative (LA) and blow-off (BO) shock waves (SW) during laser excitation provide a valuable insight into the energy release of the polymers. LASW and LBOSW during 7 ns laser pulse (532 nm, 10Hz) interaction with $\sim$ 200 micron thick HTPB and its variants with energetic additives taken in the form of a sheet were studied simultaneously using defocused shadowgraphic imaging over 0.2 - 30 $\mu$s time scales. The results were compared with non-energetic polyvinyl chloride (PVC) under same experimental conditions. The SW was observed to propagate faster through the HTPB variant compared to HTPB. Appearance of LBOSW at different time scales for the polymers revealed the shock propagation characteristics through the polymers. [Preview Abstract] |
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W1.00066: Disruption of cell membranes via laser-activated, acoustically active, carbon nanoparticles Stefany Holguin, Michael Gray, Mark Prausnitz, Naresh Thadhani Physical drug delivery methods provide an avenue to overcome the selectivity of the cell membrane via physical forces that disrupt cell membranes and drive drug molecules into the cytosol. When carbon black nanoparticles in suspension with cells and drug molecules are exposed to nanosecond-pulsed laser light, high uptake and cell viability are observed. This laser-carbon nanoparticle interaction causes thermal expansion and local vaporization that results in the release of acoustic waves into the surrounding medium. These combined energy transduction mechanisms, phenomena called transient nanoparticle energy transduction (TNET), are responsible for disruption of the cell membrane and subsequent efficient intracellular drug uptake while maintaining high cell viability. The overall objective of this work is to investigate TNET and the bioeffects associated with physical disruption of cell membranes for drug delivery via laser-carbon nanoparticle interactions. For example, varying and quantifying energy input to carbon nanoparticles by way of laser beam manipulation, assists in the understanding and assessment of subsequent bioeffects. Results of work performed to date will be presented. [Preview Abstract] |
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W1.00067: FOCUS SESSION: VELOCIMETRY DIAGNOSTICS |
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W1.00068: Development of a Spatially-Resolved Microwave Interferometer Paul Specht, Marcia Cooper The development of a spatially-resolved microwave interferometer (SRMI) for non-invasively measuring the internal transit of a shock, detonation, or reaction front in energetic media is presented. Utilizing the transparency of many energetic materials in the RF regime, current microwave interferometers provide continuum-level tracking of the dielectric discontinuity that occurs across a shock or reaction front. While this continuum-level response can provide bulk shock and detonation velocities, it is insufficient to understand the complex wave and material interactions present in heterogeneous energetic materials. Leveraging interferometry and terahertz spectroscopy techniques, a heterodyne, spatially-resolved microwave interferometer was designed. A theoretical description of its operation and potential impact to current energetic materials research is discussed. Preliminary experimental results, including electro-optic sensing of a Doppler shifted microwave beam, are presented. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2015-0308A. [Preview Abstract] |
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W1.00069: Ghost fringe removal techniques using Lissajous data presentation David Erskine, Jon Eggert, Peter Celliers, Damien Hicks Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can obscure and complicate the true signal. Accurately removing this so-called ghost component is essential for achieving high accuracy EOS measurements, especially when the true signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing the raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the true center of this curve, since the ghost contribution is solved by a translation in the complex plane that recenters the Lissajous. For continuous velocity histories, we find that plotting the fringe visibility vs nonfringing intensity and optimizing linearity is a valuable tool for determining the proper ghost offsets. For discontinuous velocity histories, we have developed equations which relate the results of two VISARs having different velocity per fringe proportionalities to find the true Lissjous center. [Preview Abstract] |
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W1.00070: POSTDEADLINE |
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W1.00071: ABSTRACT MOVED TO Y2.00005 |
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W1.00072: Hydrodynamic simulations of microjetting from shock-loaded grooves Caroline Roland, Thibaut de Resseguier, Arnaud Sollier, Emilien Lescoute, Laurent Soulard, Didier Loison The interaction of a shock wave with a free surface presenting geometrical defects, such as cavities or grooves, may lead to the ejection of micrometric debris at velocities of km/s order. This process can be involved in many applications, like pyrotechnics or industrial safety. Laser shock experiments reported in this conference (T. de Resseguier, C. Roland et al., abstract ref.000066) provide insight into jet formation and peak velocities for various groove angles and shock pressures. Here, we present hydrodynamic simulations of these experiments, in both 2D and 3D geometries, using both finite element method and smoothed particles hydrodynamics. Numerical results are compared to several theoretical predictions including the Richtmyer-Meshkov instabilities. The role of the elastic-plastic behavior on jet formation is investigated. Finally, the possibility to simulate the late stages of jet expansion and fragmentation is explored, to evaluate the mass distribution of the ejecta and their ballistic properties, still essentially unknown in the experiments. [Preview Abstract] |
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W1.00073: ABSTRACT MOVED TO S1.00002 |
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W1.00074: NON-Shock-Plasticity/Fracture Burst Acoustic-Emission(BAE) ``1''/f -``Noise'' Power-Spectrum(PS) Power-Law UNIVERSALITY is Merely F$=$ma Time-Series Integral-Transform, aka ``Bak'' -``SOC'' REdiscovery'' PRE(1687)-''Bak''(1988) Edward Siegel NON-shock plasticity/fracture BAE[E.S.:MSE 8,310(71);PSS:(a)5,601/607(71);Xl.-Latt.Defects 5,277(74); Scripta Met.:6,785(72);8,587/617(74);3rd Tokyo AE Symp.(76);Acta Met. 5,383(77);JMMM 7,312(78)] ``1''/$\omega $-``noise'' power-spectrum ``pink''-Zipf(NOT ``red''$=$Pareto) power-law UNIVERSALITY is manifestly-demonstrated in two distinct ways to be nothing but Newton 3$^{\mathrm{rd}}$ Law of Motion F $=$ ma REdiscovery!!! (aka ``Bak''(1988)-``SOC'':1687 \textless \textless \textless 1988: 1988-1687$=$301-years!!! PHYSICS:F$=$ma cross-multiplied as 1/m$=$a/F$=$OUTPUT/INPUT$=$ EFFECT/CAUSE$=$inverse-mass mechanical-susceptibility$=\chi $(''$\omega $''); $\chi $(''$\omega $ '')$\sim $(F.-D.thm.)$\sim $P(''$\omega $'') ''noise'' power-spectrum; (``Max {\&} Al show''): E$\sim \omega $; {\&} E$\sim $(upper-limiting-speeds media)$\sim $m. Thus: $\omega \sim $E$\sim $m; Inverting: 1/$\omega \sim $1/E $\sim $1/m$\sim $a/F$=\chi $(''$\omega $'')$\sim $P(''$\omega $''); Thus: F$=$ma integral-transform(I-T) is '''SOC'''s'' P($\omega )\sim $1/$\omega $!!! ; ''PURE''-MATHS: F$=$ma DOUBLE-integral time-series(T-S) s(t)$=$[v$_{\mathrm{0}}$t$+$(1/2)at$^{\mathrm{2}}$] I-T formally de?nes power-spectrum(PS): P($\omega )\equiv \smallint $s(t)e$^{\mathrm{-i\omega t}}$dt$=\smallint $[v$_{\mathrm{o}}$t$+$(1/2)at$^{\mathrm{2}}$]e$^{\mathrm{-i\omega t}}$dt$=$ v$_{\mathrm{o}}\smallint $a(t)e$^{\mathrm{-i\omega t}}$dt$+$(1/2)[a$\ne $a(t)]$\smallint $t$^{\mathrm{2}}$e$^{\mathrm{-i\omega t}}$dt$=$v$_{\mathrm{o}}(\partial $/$\partial \omega )\delta (\omega )+$(1/2)[a$\ne $a(t)]($\partial^{\mathrm{2}}$/$\partial \omega ^{\mathrm{2}})\delta (\omega )=$v$_{\mathrm{o}}$/$\omega ^{\mathrm{0}}+$ (1/2)[a$\ne $a(t)]/$\omega ^{\mathrm{1.000\mathellipsis }}$; uniform-velocity a$=$0 PS P($\omega )=$1/$\omega^{\mathrm{o}}$ WHITE vs. uniform:-a\textgreater 0;a\textless 0) PS P($\omega )=$1/$\omega^{\mathrm{1.000\mathellipsis }}$ pink/flicker/HYPERBOLICITY. [Preview Abstract] |
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