Effect of Particle Morphology on the Reactivity of Explosively Dispersed Titanium Particles

NASA Astrophysics Data System (ADS)

Frost, David L.; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2009-12-01

The effect of particle morphology on the reaction of titanium (Ti) particles explosively dispersed during the detonation of either cylindrical or spherical charges has been investigated experimentally. The explosive charges consisted of packed beds of Ti particles saturated with nitromethane. The reaction behaviour of irregularly-shaped Ti particles in three size ranges is compared with tests with spherical Ti particles. The particle reaction is strongly dependent on particle morphology, e.g., 95 μm spherical Ti particles failed to ignite (in cylinders up to 49 mm in dia), whereas similarly sized irregular Ti particles readily ignited. For irregular particles, the uniformity of ignition on the particle cloud surface was almost independent of particle size, but depended on charge diameter. As the charge diameter was reduced, ignition in the conically expanding particle cloud occurred only at isolated spots or bands. For spherical charges, whereas large irregular Ti particles ignited promptly and uniformly throughout the particle cloud, the smallest particles dispersed nonuniformly and ignition occurred at isolated locations after a delay. Hence the charge geometry, as well as particle morphology, influences the reaction behaviour of the particles.

Correlating shaped charge performance with processing conditions and microstructure of an aluminum alloy 1100 liner enabled by a new method to arrest nascent jet formation

NASA Astrophysics Data System (ADS)

Scheid, James Eric

Aluminum-lined shaped charges are used in special applications where jet and / or slug residue in the target is undesired. The three different microstructures of the aluminum liners studied herein resulted from three different manufacturing interpretations of the same design. One interpretation was completely machining the liners from best available annealed round stock. The second was to cold-forge the liners from annealed round-stock in an open-die forge to near-final dimensions, and then machine the liners to the final dimensions. The third variant in this study was to use the above forged liner, but with annealing after the machining. These three manufacturing choices resulted in significant variations in shaped charge performance. The goal of this research was to clarify the relationships between the liner metal microstructure and properties, and the corresponding shaped charge dynamic flow behavior. What began as an investigation into user-reported performance problems associated inherently with liner manufacturing processes and resultant microstructure, resolved into new understandings of the relationships between aluminum liner microstructure and shaped charge collapse kinetics. This understanding was achieved through an extensive literature review and the comprehensive characterization of the material properties of three variants of an 1100 aluminum shaped charge liner with a focus on collapse and nascent jet formation. The machined liner had a microstructure with large millimeter-sized grains and fine particles aligned in bands parallel to the charge axis. The forged liner microstructure consisted of very small one micrometer-sized (1 mum) subgrains and fine particles aligned largely in bands elongated parallel to the liner contour. The annealed liner was characterized by ten micrometer (10 mum) sized equiaxed grains with residual fine particles in the forged alignment. This characterization was enabled by the development, execution and validation of a custom explosive experiment that delivered meaningful, full-scale shock deformed samples for analysis. The experiment arrested the collapse of actual, as-fabricated liners in the first microseconds of development. This experiment, performed with only 2% of the explosive mass of the full charge, revealed new insights into material-dependent variations in liner collapse including a striking image of the formation of a shaped charge jet axial hole. The highly strain-hardened and elongated forged liner was the best performer of the three. Less energy from the explosive was dissipated by dislocation generation. This translated to more efficient flow whereas the softer materials behaved as shock absorbers delaying flow. A set of hypotheses was formulated and critiqued based on these observations. The key findings were the effects of grain size, and shear bands induced in the microstructure through cold work enabled efficient liner flow. These bands provide highly localized dislocation highways enabling the matrix adjacent to the bands to deform plastically at higher velocity. Where such bands are unavailable, the pressure must first develop bands of smaller grains, thus decreasing energy available for flow. Collapse velocities were then associated with the number of shear bands, the organization of mobile dislocations, material strain, and liner geometry. Microstructures with the ability to deform with the direction of liner collapse at lower stresses will form jets with a higher velocity and elongate earlier. The effect is higher performance at shorter standoffs. This relationship can be used to predict material behavior under explosive load, guiding engineering choices while designing with respect to anticipated shock loading. The explosive experiment designed here has obvious application in refining the performance of other warheads, and in the hydrodynamic modeling of material properties.

Modeling and Optimization of Shaped Charge Liner Collapse and Jet Formation

DTIC Science & Technology

1993-01-01

Properties of Chemical Explosives and Explosive Simulants," Technical Report UCRL -52997, University of California, CA, 1981. 22. Mader, C. L., "FORTRAN...Numerical Modeling of Detonations, University of California Press, CA, 19,9. 49. Wilkens, M. L., "The Equation of State of PBX 9404 and LX04-01 ," Report UCRL ...of High Explosive Detonation Products, Report UCRL -50422, University of Califor- nia, CA, 1968. 51. Green, L. G.; Traver, C. M.; and Erskine, D. J

Base surge in recent volcanic eruptions

USGS Publications Warehouse

Moore, J.G.

1967-01-01

A base surge, first identified at the Bikini thermonuclear undersea explosion, is a ring-shaped basal cloud that sweeps outward as a density flow from the base of a vertical explosion column. Base surges are also common in shallow underground test explosions and are formed by expanding gases which first vent vertically and then with continued expansion rush over the crater lip (represented by a large solitary wave in an underwater explosion), tear ejecta from it, and feed a gas-charged density flow, which is the surge cloud. This horizontally moving cloud commonly has an initial velocity of more than 50 meters per second and can carry clastic material many kilometers. Base surges are a common feature of many recent shallow, submarine and phreatic volcanic eruptions. They transport ash, mud, lapilli, and blocks with great velocity and commonly sandblast and knock down trees and houses, coat the blast side with mud, and deposit ejecta at distances beyond the limits of throw-out trajectories. Close to the eruption center, the base surge can erode radial channels and deposit material with dune-type bedding. ?? 1967 Stabilimento Tipografico Francesco Giannini & Figli.

On the Interaction and Coalescence if Spherical Blast Waves

NASA Technical Reports Server (NTRS)

Kandula, Max; Freeman, Robert J.

2005-01-01

The scaling and similarity laws concerning the propagation of isolated spherical blast waves are briefly reviewed. Both point source explosions and high pressure gas explosions are considered. Test data on blast overpressure from the interaction and coalescence of spherical blast waves emanating from explosives in the form of shaped charges of different strength placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure. The results point out the possibility of detecting source explosions from far-field pressure measurements.

Precision Blasting Techniques For Avalanche Control

NASA Astrophysics Data System (ADS)

Powell, Kevin M.

Experimental firings sponsored by the Center For Snow Science at Alta, Utah have demonstrated the potential of a unique prototype shaped charge device designed to stimulate snow pack and ice. These studies, conducted against stable snow pack, demonstrated a fourfold increase in crater volume yield and introduced a novel application of Shock Tube technology to facilitate position control, detonation and dud recovery of manually deployed charges. The extraordinary penetration capability of the shaped charge mechanism has been exploited in many non-military applications to meet a wide range of rapidpiercing and/or cutting requirements. The broader exploitation of the potential of the shaped charge mechanism has nevertheless remained confined to defence based applications. In the studies reported in this paper, the inimitable ability of the shaped charge mechanism to project shock energy, or a liner material, into a highly focussed energetic stream has been applied uniquely to the stimulation of snow pack. Recent research and development work, conducted within the UK, has resulted in the integration of shaped charge technology into a common Avalauncher and hand charge device. The potential of the common charge configuration and spooled Shock Tube fire and control system to improve the safety and cost effectiveness of explosives used in avalanche control operations was successfully demonstrated at Alta in March 2001. Future programmes of study will include focussed shock/blast mechanisms for suspended wire traverse techniques, application of the shaped charge mechanism to helibombing, and the desig n and development of non-fragmenting shaped charge ammunition formilitary artillery gun systems.

Explosive destruction system for disposal of chemical munitions

DOEpatents

Tschritter, Kenneth L [Livermore, CA; Haroldsen, Brent L [Manteca, CA; Shepodd, Timothy J [Livermore, CA; Stofleth, Jerome H [Albuquerque, NM; DiBerardo, Raymond A [Baltimore, MD

2005-04-19

An explosive destruction system and method for safely destroying explosively configured chemical munitions. The system comprises a sealable, gas-tight explosive containment vessel, a fragment suppression system positioned in said vessel, and shaped charge means for accessing the interior of the munition when the munition is placed within the vessel and fragment suppression system. Also provided is a means for treatment and neutralization of the munition's chemical fills, and means for heating and agitating the contents of the vessel. The system is portable, rapidly deployable and provides the capability of explosively destroying and detoxifying chemical munitions within a gas-tight enclosure so that there is no venting of toxic or hazardous chemicals during detonation.

Studies on formation of unconfined detonable vapor cloud using explosive means.

PubMed

Apparao, A; Rao, C R; Tewari, S P

2013-06-15

Certain organic liquid fuels like hydrocarbons, hydrocarbon oxides, when dispersed in air in the form of small droplets, mix with surrounding atmosphere forming vapor cloud (aerosol) and acquire explosive properties. This paper describes the studies on establishment of conditions for dispersion of fuels in air using explosive means resulting in formation of detonable aerosols of propylene oxide and ethylene oxide. Burster charges based on different explosives were evaluated for the capability to disperse the fuels without causing ignition. Parameters like design of canister, burster tube, burster charge type, etc. have been studied based on dispersion experiments. The detonability of the aerosol formed by the optimized burster charge system was also tested. Copyright © 2013 Elsevier B.V. All rights reserved.

An investigation of the cratering-induced motions occurring during the formation of bowl-shaped craters. [using high explosive charges as the cratering source

NASA Technical Reports Server (NTRS)

Piekutowski, A. J.

1980-01-01

The effects of the dynamic processes which occur during crater formation were examined using small hemispherical high-explosive charges detonated in a tank which had one wall constructed of a thick piece of clear plexiglas. Crater formation and the motions of numerous tracer particles installed in the cratering medium at the medium-wall interface were viewed through the wall of this quarter-space tank and recorded with high-speed cameras. Subsequent study and analysis of particle motions and events recorded on the film provide data needed to develop a time-sequence description of the formation of a bowl-shaped crater. Tables show the dimensions of craters produced in a quarter-space tank compared with dimensions of craters produced in normal half-space tanks. Crater growth rate summaries are also tabulated.

Determination of detonation wave boundary angles via hydrocode simulations using CREST

NASA Astrophysics Data System (ADS)

Whitworth, N. J.; Childs, M.

2017-01-01

A key input parameter to Detonation Shock Dynamics models is the angle that the propagating detonation wave makes with the charge edge. This is commonly referred to as the boundary angle, and is a property of the explosive/confiner material combination. Such angles can be determined: (i) experimentally from measured detonation wave-shapes, (ii) theoretically, or (iii) via hydrocode simulations using a reactive burn model. Of these approaches: (i) is difficult because of resolution, (ii) breaks down for certain configurations, while (iii) requires a well validated model. In this paper, the CREST reactive burn model, which has previously been successful in modelling a wide range of explosive phenomena, is used to simulate recent Detonation Confinement Sandwich Tests conducted at LANL using the insensitive high explosive PBX 9502. Simulated detonation wave-shapes in PBX 9502 for a number of different confiner materials and combinations closely match those recorded from the experiments. Boundary angles were subsequently extracted from the simulated results via a wave-shape analysis toolkit. The results shown demonstrate the usefulness of CREST in determining detonation wave boundary angles for a range of explosive/confiner material combinations.

Penetration and Cutting Effects of Lead-Sheathed Flexible Linear Shaped Charges and Explosive-Filled Linear Shaped-Charge Containers (Mark 7 Mods 1 through 8 and Mark 8 Mod 2)

DTIC Science & Technology

1978-11-01

in.) 90% 3. Probabilty of cutting greater than 6.385 mm (0.212 in.) 95% 5.105 mm (0 201 in.) 99% 4 Probability of cutting between 5.588 mm (0 220 in...deviation. 1.651 mm (0.065 in.) 13.685 mm (0.538 in.) 75% 12.675 mm (0.499 in.) 90% 3. Probabilty of cutting greater than 12.065 mm (0.475 in.) 95% 10.947 mm

Static structure of a pointed charged drop

NASA Astrophysics Data System (ADS)

Fernandez de La Mora, Juan

2017-11-01

The static equilibrium structure of an equipotential drop with two symmetric Taylor cones is computed by assigning a charge distribution along the z axis q (z) = ∑Bn (L2 -z2)n + 1 / 2 . Taylor's local equilibrium at the poles z = L , - L fixes two of the Bn coefficients as a function of the other, determined by minimizing stress imbalance. Just two optimally chosen terms in the Bn expansion yield imperceptible errors. Prior work has argued that an exploding drop initially carrying Rayleigh's charge qR is quasi static. Paradoxically, quasi-static predictions on the size of the progeny drops emitted during a Coulombic explosion disagree with observations. The static drop structure found here also models poorly a Coulomb explosion having an equatorial over polar length ratio (0.42) and the a drop charge exceeding those observed (0.28-0.36 and qR / 2). Our explanation for this paradox is that, while the duration tc of a Coulomb explosion is much larger than the charge relaxation time, the dynamic time scale for drop elongation is typically far longer than tc. Therefore, the pressure distribution within the exploding drop is not uniform. A similar analysis for a drop in an external field fits well the experimental shape.

Effect of Particle Morphology on the Reactivity of Explosively Dispersed Titanium Particles

NASA Astrophysics Data System (ADS)

Frost, David; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2009-06-01

The effect of particle morphology on the reaction of titanium (Ti) particles explosively dispersed during the detonation of either cylindrical or spherical charges has been investigated experimentally. The explosive charges consisted of packed beds of Ti particles saturated with nitromethane. The reaction behavior of irregularly-shaped Ti particles in three size ranges is compared with tests with spherical Ti particles. The particle reaction is strongly dependent on particle morphology, e.g., 95 μm spherical Ti particles failed to ignite (in cylinders up to 49 mm in dia), whereas similarly sized irregular Ti particles readily ignited. For irregular particles, the uniformity of ignition on the particle cloud surface was almost independent of particle size, but depended on charge diameter. As the charge diameter was reduced, ignition in the conically expanding particle cloud occurred only at isolated spots or bands. For spherical charges, although large irregular Ti particles ignited promptly and uniformly throughout the particle cloud, the smallest particles dispersed nonuniformly and ignition occurred at isolated locations. In general, particle ignition is a competition between particle heating (which is influenced by particle morphology, size, number density and the local thermodynamic history) and expansion cooling of the products.

Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

USGS Publications Warehouse

Thomas, Ronald J.; Krehbiel, Paul R.; Rison, William; Edens, H. E.; Aulich, G. D.; McNutt, S.R.; Tytgat, Guy; Clark, E.

2007-01-01

By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.

A high-altitude barium radial injection experiment

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Deehr, C. S.; Romick, G. J.; Olson, J. V.; Roederer, J. G.; Sydora, R.

1980-01-01

A rocket launched from Poker Flat, Alaska, carried a new type of high-explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The TV images of the injection are spectacular, revealing three major regimes of expanding plasma which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium-ion structure lying in the injection plane and centered on a 5 km 'black hole' surrounding the injection point. Preliminary electrostatic computer simulations show a similar rayed development.

Explosive bulk charge

DOEpatents

Miller, Jacob Lee

2015-04-21

An explosive bulk charge, including: a first contact surface configured to be selectively disposed substantially adjacent to a structure or material; a second end surface configured to selectively receive a detonator; and a curvilinear side surface joining the first contact surface and the second end surface. The first contact surface, the second end surface, and the curvilinear side surface form a bi-truncated hemispherical structure. The first contact surface, the second end surface, and the curvilinear side surface are formed from an explosive material. Optionally, the first contact surface and the second end surface each have a substantially circular shape. Optionally, the first contact surface and the second end surface consist of planar structures that are aligned substantially parallel or slightly tilted with respect to one another. The curvilinear side surface has one of a smooth curved geometry, an elliptical geometry, and a parabolic geometry.

Inductive Measurement of Plasma Jet Electrical Conductivity

NASA Technical Reports Server (NTRS)

Turner, Matthew W.; Hawk, Clark W.; Litchford, Ron J.

2005-01-01

An inductive probing scheme, originally developed for shock tube studies, has been adapted to measure explosive plasma jet conductivities. In this method, the perturbation of an applied magnetic field by a plasma jet induces a voltage in a search coil, which, in turn, can be used to infer electrical conductivity through the inversion of a Fredholm integral equation of the first kind. A 1-inch diameter probe was designed and constructed, and calibration was accomplished by firing an aluminum slug through the probe using a light-gas gun. Exploratory laboratory experiments were carried out using plasma jets expelled from 15-gram high explosive shaped charges. Measured conductivities were in the range of 3 kS/m for unseeded octol charges and 20 kS/m for seeded octol charges containing 2% potassium carbonate by mass.

Peculiarity of convergence of shock wave generated by underwater electrical explosion of ring-shaped wire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shafer, D.; Toker, G. R.; Gurovich, V. Tz.

2013-05-15

Nanosecond timescale underwater electrical wire explosions of ring-shaped Cu wires were investigated using a pulsed generator with a current amplitude up to 50 kA. It was shown that this type of wire explosion results in the generation of a toroidal shock wave (SW). Time- and space-resolved optical diagnostics were used to determine azimuthal uniformity of the shock wave front and its velocity. It was found that the shock wave preserves its circular front shape in the range of radii 50μm

Forensic analysis of explosions: Inverse calculation of the charge mass.

PubMed

van der Voort, M M; van Wees, R M M; Brouwer, S D; van der Jagt-Deutekom, M J; Verreault, J

2015-07-01

Forensic analysis of explosions consists of determining the point of origin, the explosive substance involved, and the charge mass. Within the EU FP7 project Hyperion, TNO developed the Inverse Explosion Analysis (TNO-IEA) tool to estimate the charge mass and point of origin based on observed damage around an explosion. In this paper, inverse models are presented based on two frequently occurring and reliable sources of information: window breakage and building damage. The models have been verified by applying them to the Enschede firework disaster and the Khobar tower attack. Furthermore, a statistical method has been developed to combine the various types of data, in order to determine an overall charge mass distribution. In relatively open environments, like for the Enschede firework disaster, the models generate realistic charge masses that are consistent with values found in forensic literature. The spread predicted by the IEA tool is however larger than presented in the literature for these specific cases. This is also realistic due to the large inherent uncertainties in a forensic analysis. The IEA-models give a reasonable first order estimate of the charge mass in a densely built urban environment, such as for the Khobar tower attack. Due to blast shielding effects which are not taken into account in the IEA tool, this is usually an under prediction. To obtain more accurate predictions, the application of Computational Fluid Dynamics (CFD) simulations is advised. The TNO IEA tool gives unique possibilities to inversely calculate the TNT equivalent charge mass based on a large variety of explosion effects and observations. The IEA tool enables forensic analysts, also those who are not experts on explosion effects, to perform an analysis with a largely reduced effort. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Initiation Capacity of a Specially Shaped Booster Pellet and Numerical Simulation of Its Initiation Process

NASA Astrophysics Data System (ADS)

Hu, Li-Shuang; Hu, Shuang-Qi; Cao, Xiong; Zhang, Jian-Ren

2014-01-01

The insensitive main charge explosive is creating new requirements for the booster pellet of detonation trains. The traditional cylindrical booster pellet has insufficient energy output to reliably initiate the insensitive main charge explosive. In this research, a concave spherical booster pellet was designed. The initiation capacity of the concave spherical booster pellet was studied using varied composition and axial steel dent methods. The initiation process of the concave spherical booster pellet was also simulated by ANSYS/LS-DYNA. The results showed that using a concave spherical booster allows a 42% reduction in the amount of explosive needed to match the initiation capacity of a conventional cylindrical booster of the same dimensions. With the other parameters kept constant, the initiation capacity of the concave spherical booster pellet increases with decreased cone angle and concave radius. The numerical simulation results are in good agreement with the experimental data.

Accelerating monoenergetic protons from ultrathin foils by flat-top laser pulses in the directed-Coulomb-explosion regime

PubMed Central

Bulanov, S. S.; Brantov, A.; Bychenkov, V. Yu.; Chvykov, V.; Kalinchenko, G.; Matsuoka, T.; Rousseau, P.; Reed, S.; Yanovsky, V.; Litzenberg, D. W.; Krushelnick, K.; Maksimchuk, A.

2008-01-01

We consider the effect of laser beam shaping on proton acceleration in the interaction of a tightly focused pulse with ultrathin double-layer solid targets in the regime of directed Coulomb explosion. In this regime, the heavy ions of the front layer are forced by the laser to expand predominantly in the direction of the pulse propagation, forming a moving longitudinal charge separation electric field, thus increasing the effectiveness of acceleration of second-layer protons. The utilization of beam shaping, namely, the use of flat-top beams, leads to more efficient proton acceleration due to the increase of the longitudinal field. PMID:18850951

Jet Formation and Penetration Study of Double-Layer Shaped Charge

NASA Astrophysics Data System (ADS)

Wang, Zhe; Jiang, Jian-Wei; Wang, Shu-You; Liu, Han

2018-04-01

A theoretical analysis on detonation wave propagation in a double-layer shaped charge (DLSC) is performed. Numerical simulations using the AUTODYN software are carried out to compare the distinctions between jet formations in DLSC and ordinary shaped charge (OSC), in particular, the OSC made using a higher detonation velocity explosive, which is treated as the outer layer charge in the DLSC. The results show that the improved detonation velocity ratio and radial charge percentage of outer-to-inner layer charge are conducive to the formation of a convergent detonation wave, which contributes to enhancement of jet tip velocity in DLSC. The thickness and mass percentages of liner flowing into jet in DLSC closely follow the exponential distribution along the radial direction, but the percentages in DLSC and the mass of effective jet, which have significant influence on the penetration depth, are lower than those in OSC with the outer layer charge. This implies that the total charge energy is the major factor controlling the effective jet formation, which is confirmed by the verification tests using flash X-ray system and following penetration tests. The numerical simulation and test results compare well, while penetration test results indicate that the performance of DLSC is not better than that of OSC with the outer layer charge, due to the differences in jet formation.

Investigating ground effects on mixing and afterburning during a TNT explosion

NASA Astrophysics Data System (ADS)

Fedina, E.; Fureby, C.

2013-05-01

In this paper, the unconfined and semi-confined condensed phase explosions of TNT will be studied using large eddy simulations based on the unsteady, compressible, reacting, multi-species Navier-Stokes equations to gain further understanding of the physical processes involved in a condensed phase explosion and the effect of confinement on the physical processes involved. The analysis of the mixing and afterburning of TNT explosions in free air (unconfined) and near the ground (semi-confined) indicates that the combustion region of detonation products and air is determined by the vorticity patterns, which are induced by the Richtmeyer-Meshkov instabilities that arise during the explosion. When the explosive is detonated in the vicinity of a surface, the surface affects the shock propagation by creating complex shock systems, thereby changing the orientation of the vorticity, giving the afterburning a mushroom shape, and increasing performance of an explosive charge by prolonging the existence of the mixing layer and thereby the afterburning.

Characterizing the energy output generated by a standard electric detonator using shadowgraph imaging

NASA Astrophysics Data System (ADS)

Petr, V.; Lozano, E.

2017-09-01

This paper overviews a complete method for the characterization of the explosive energy output from a standard detonator. Measurements of the output of explosives are commonly based upon the detonation parameters of the chemical energy content of the explosive. These quantities provide a correct understanding of the energy stored in an explosive, but they do not provide a direct measure of the different modes in which the energy is released. This optically based technique combines high-speed and ultra-high-speed imaging to characterize the casing fragmentation and the detonator-driven shock load. The procedure presented here could be used as an alternative to current indirect methods—such as the Trauzl lead block test—because of its simplicity, high data accuracy, and minimum demand for test repetition. This technique was applied to experimentally measure air shock expansion versus time and calculating the blast wave energy from the detonation of the high explosive charge inside the detonator. Direct measurements of the shock front geometry provide insight into the physics of the initiation buildup. Because of their geometry, standard detonators show an initial ellipsoidal shock expansion that degenerates into a final spherical wave. This non-uniform shape creates variable blast parameters along the primary blast wave. Additionally, optical measurements are validated using piezoelectric pressure transducers. The energy fraction spent in the acceleration of the metal shell is experimentally measured and correlated with the Gurney model, as well as to several empirical formulations for blasts from fragmenting munitions. The fragment area distribution is also studied using digital particle imaging analysis and correlated with the Mott distribution. Understanding the fragmentation distribution plays a critical role when performing hazard evaluation from these types of devices. In general, this technique allows for characterization of the detonator within 6-8% error with no knowledge of the amount or type of explosive contained within the shell, making it also suitable for the study of unknown improvised explosive devices.

Spark-safe low-voltage detonator

DOEpatents

Lieberman, Morton L.

1989-01-01

A column of explosive in a low-voltage detonator which makes it spark-safe ncludes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4) each of which has an axial thickness-to-diameter ratio of one to two.

Spark-safe low-voltage detonator

DOEpatents

Lieberman, M.L.

1988-07-01

A column of explosive in a low-voltage detonator which makes it spark-safe includes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4), each of which has an axial thickness-to-diameter ratio of one to two. 2 figs.

Twinning, texture and constitutive relations for explosively formed jets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiferl, S.K.

1989-01-01

We have used crystallographic-texture calculations to simulate the evolution of preferred grain orientations, and the corresponding changes in anisotropic plasticity, during explosively-driven liner collapse in metallic shaped-charge jets. For hcp metals, twinning tends to be an important deformation mechanism, and twinning is known to be strongly influenced by shocks. We consider cases of enhanced and inhibited twinning for titanium and titanium-alloys; the consequences of these treatments for the evolution of plasticity in early jet formation are discussed. 10 refs., 3 figs., 1 tab.

Times and locations of explosions; U.S. Geological Survey 1962 field season

USGS Publications Warehouse

Roller, John C.

1962-01-01

The U.S. Geological Survey detonated 86 large charges of chemical explosives in the western United States from 6 June to 9 August 1962, in a study of crustal structure in the western United States. This Technical Letter consists of two tables containing information about these explosions. Table I gives a brief geographical description of the shotpoints, and Table II gives the date, time, location, charge size, surface elevation, and some general information about the shots. In the Remarks column (Table II), the configuration and depth of most of the charges are given. This part of the table is not complete, as some of this information has not yet been compiled. Three types of explosives were used in the program. These were: Nitramon WW, a carbo-nitrate blasting agent; Composition B, a mixture of RDX and TNT; and Tovex-Gel, a non-nitroglycerin blasting slurry. The loading, firing, and surveying was done by United ElectroDynamics, Inc., of Pasadena, California. The timing was done by the U.S. Geological Survey.

Reaction of Titanium and Zirconium Particles in Cylindrical Explosive Charges

NASA Astrophysics Data System (ADS)

Frost, David L.; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2007-12-01

The critical conditions for the reaction of particles of the transition metals titanium (Ti) and zirconium (Zr) dispersed during the detonation of long cylindrical explosive charges have been investigated experimentally. The charges consisted of packed beds of either spherical Ti particles or irregularly shaped Zr particles saturated with sensitized liquid nitromethane. For the Ti particles, a threshold particle diameter exists of 65±25 μm, above which self-sustained particle reaction is not observed for charge diameters up to 49 mm, although some particle reaction occurs immediately behind the detonation front then rapidly quenches. For the smallest particles (40 μm), the proportion of the conical particle cloud that reacts increases with charge diameter, suggesting that the reaction is a competition between particle heating and expansion cooling of the products. For 375 and 550 μm Zr particles, particle ignition was observed for 19 and 41 mm dia charges. In this case, interaction of the detonation wave with the particles is sufficient to initiate reaction at the particle surface after a delay time (˜5 μs), which is much less than the time required for thermal equilibration of the particles.

The behavior limestone under explosive load

NASA Astrophysics Data System (ADS)

Orlov, M. Yu; Orlova, Yu N.; Bogomolov, G. N.

2016-11-01

Limestone behavior under explosive loading was investigated. The behavior of the limestone by the action of the three types of explosives, including granular, ammonite and emulsion explosives was studied in detail. The shape and diameter of the explosion craters were obtained. The observed fragments after the blast have been classified as large, medium and small fragments. Three full-scale experiments were carried out. The research results can be used as a qualitative test for the approbation of numerical methods.

Method for forming an in situ oil shale retort with horizontal free faces

DOEpatents

Ricketts, Thomas E.; Fernandes, Robert J.

1983-01-01

A method for forming a fragmented permeable mass of formation particles in an in situ oil shale retort is provided. A horizontally extending void is excavated in unfragmented formation containing oil shale and a zone of unfragmented formation is left adjacent the void. An array of explosive charges is formed in the zone of unfragmented formation. The array of explosive charges comprises rows of central explosive charges surrounded by a band of outer explosive charges which are adjacent side boundaries of the retort being formed. The powder factor of each outer explosive charge is made about equal to the powder factor of each central explosive charge. The explosive charges are detonated for explosively expanding the zone of unfragmented formation toward the void for forming the fragmented permeable mass of formation particles having a reasonably uniformly distributed void fraction in the in situ oil shale retort.

Sidewall penetrator for oil wells

NASA Technical Reports Server (NTRS)

Collins, E. R., Jr.

1981-01-01

Penetrator bores horizontal holes in well casing to increase trapped oil drainage. Several penetrators operated by common drive are inserted into well at once. Shaft, made from spiraling cable, rotates and thrusts simultaneously through rigid curvilinear guide tube forcing bit through casing into strata. Device pierces more deeply than armor-piercing bullets and shaped explosive charges.

Planar blast scaling with condensed-phase explosives in a shock tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Scott L

2011-01-25

Blast waves are strong shock waves that result from large power density deposition into a fluid. The rapid energy release of high-explosive (HE) detonation provides sufficiently high power density for blast wave generation. Often it is desirable to quantify the energy released by such an event and to determine that energy relative to other reference explosives to derive an explosive-equivalence value. In this study, we use condensed-phase explosives to drive a blast wave in a shock tube. The explosive material and quantity were varied to produce blast waves of differing strengths. Pressure transducers at varying lengths measured the post-shock pressure,more » shock-wave arrival time and sidewall impulse associated with each test. Blast-scaling concepts in a one-dimensional geometry were then used to both determine the energy release associated with each test and to verify the scaling of the shock position versus time, overpressure versus distance, and impulse. Most blast scaling measurements to-date have been performed in a three-dimensional geometry such as a blast arena. Testing in a three-dimensional geometry can be challenging, however, as spherical shock-wave symmetry is required for good measurements. Additionally, the spherical wave strength decays rapidly with distance and it can be necessary to utilize larger (several kg) quantities of explosive to prevent significant decay from occurring before an idealized blast wave has formed. Such a mode of testing can be expensive, require large quantities of explosive, and be limited by both atmospheric conditions (such as rain) and by noise complaints from the population density near the test arena. Testing is possible in more compact geometries, however. Non-planar blast waves can be formed into a quasi-planar shape by confining the shock diffraction with the walls of a shock tube. Regardless of the initial form, the wave shape will begin to approximate a planar front after successive wave reflections from the tube walls. Such a technique has previously been used to obtain blast scaling measurements in the planar geometry with gaseous explosives and the condensed-phase explosive nitroguanidine. Recently, there has been much interest in the blast characterization of various non-ideal high explosive (NIHE) materials. With non-ideals, the detonation reaction zone is significantly larger (up to several cm for ANFO) than more ideal explosives. Wave curvature, induced by charge-geometry, can significantly affect the energy release associated with NIHEs. To measure maximum NIHE energy release accurately, it is desirable to minimize any such curvature and, if possible, to overdrive the detonation shock to ensure completion of chemical reactions ahead of the sonic locus associated with the reaction zone. This is achieved in the current study through use of a powerful booster HE and a charge geometry consisting of short cylindrical lengths of NIHE initiated along the charge centerline.« less

Explosively activated egress area

NASA Technical Reports Server (NTRS)

Bement, L. J.; Bailey, J. W. (Inventor)

1983-01-01

A lightweight, add on structure which employs linear shaped pyrotechnic charges to smoothly cut an airframe along an egress area periphery is provided. It compromises reaction surfaces attached to the exterior surface of the airframe's skin and is designed to restrict the skin deflection. That portion of the airframe within the egress area periphery is jettisoned. Retention surfaces and sealing walls are attached to the interior surface of the airframe's skin and are designed to shield the interior of the aircraft during detonation of the pyrotechnic charges.

A Study of Shaped-Charge Collapse and Jet Formation Using the HEMP (hydrodynamic, Elastic, Magneto, and Plastic) Code and a Comparison with Experimental Observations

DTIC Science & Technology

1984-12-01

Octol** explosive. The experimental charges were lightly confined with aluminum bodies and had cone diameters of 84mm. The charges modelled using HEMP...solved using the following relationships: .Final Final V 0 1 IV sin 9, where Voz aj i teailcmpnn fj~Fnl n Final F where V is the adial component of Fnan h...velocity vector is equal to the vector addition of the flow and 8. MMiles L. Lampson, "The Influence of Convergence - Velocity Gradients on the Formation

Optically triggered fire set/detonator system

DOEpatents

Chase, Jay B.; Pincosy, Philip A.; Chato, Donna M.; Kirbie, Hugh; James, Glen F.

2007-03-20

The present invention is directed to a system having a plurality of capacitor discharge units (CDUs) that includes electrical bridge type detonators operatively coupled to respective explosives. A pulse charging circuit is adapted to provide a voltage for each respective capacitor in each CDU. Such capacitors are discharged through the electrical bridge type detonators upon receiving an optical signal to detonate respective operatively coupled explosives at substantially the same time.

Ignition-and-Growth Modeling of NASA Standard Detonator and a Linear Shaped Charge

NASA Technical Reports Server (NTRS)

Oguz, Sirri

2010-01-01

The main objective of this study is to quantitatively investigate the ignition and shock sensitivity of NASA Standard Detonator (NSD) and the shock wave propagation of a linear shaped charge (LSC) after being shocked by NSD flyer plate. This combined explosive train was modeled as a coupled Arbitrary Lagrangian-Eulerian (ALE) model with LS-DYNA hydro code. An ignition-and-growth (I&G) reactive model based on unreacted and reacted Jones-Wilkins-Lee (JWL) equations of state was used to simulate the shock initiation. Various NSD-to-LSC stand-off distances were analyzed to calculate the shock initiation (or failure to initiate) and detonation wave propagation along the shaped charge. Simulation results were verified by experimental data which included VISAR tests for NSD flyer plate velocity measurement and an aluminum target severance test for LSC performance verification. Parameters used for the analysis were obtained from various published data or by using CHEETAH thermo-chemical code.

Frequency power analyses of seismic sources on firn

NASA Astrophysics Data System (ADS)

Sanz, Christopher; Diez, Anja; Coen, Hofstede; Kristoffersen, Yngve; Mayer, Christoph; Lambrecht, Astrid; Miller, Heinz; Eisen, Olaf

2013-04-01

A great obstacle for seismic surveys on firn-covered ice masses is the ability of firn to strongly attenuate seismic energy and divert downward ray paths away from the vertical because of the velocity gradient. The standard way to overcome these limitations is the drilling of shotholes about 10-30 m deep. However, drilling of shotholes is a time and energy consuming task. Another possibility is to use vibroseismic sources at the surface and increase the signal-to-noise ratio by repeated stacking. However, compared to explosive charges, vibroseismic signals are bandlimited per se. As a third variant, we investigate the usage of ordered patterns of surface charges consisting of detonation cord. Previous applications of detonation cord only explored their general comparison to bulk explosives when deployed in a linear fashion, i.e. a single line. Our approach extends these results to other geometries, like fan- or comb-shaped patterns. These have two advantages: first, over the pattern area a locally plane wave is generated, limiting the spherical and velocity-gradient induced spreading of energy during propagation; second, the ratio between seismic wave speed of the firn and the detonation cord of typically about 1:5 causes the wave to propagate in an angle downward. When using large offsets like a snow streamer, it is possible to direct the refected energy towards the streamer, depending on offset range and reflector depth. We compare the different source types for several surveys conducted in Antarctica in terms of frequency spectra. Our results show that ordered patterns of detonation cord serve as suitable seismic surface charges, avoiding the need to drill shotholes. Moreover, an example of a short profile with patterned surface charges is presented. The technique can be of advantage for surveys in remote areas, which can only be accessed by aircrafts.

Synchro-ballistic recording of detonation phenomena

NASA Astrophysics Data System (ADS)

Critchfield, Robert R.; Asay, Blaine W.; Bdzil, John B.; Davis, William C.; Ferm, Eric N.; Idar, Deanne J.

1997-12-01

Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic detonation shock dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film's spatial dimension and the phase velocity is adjusted to provide synchronization at the camera's maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to- diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric denotation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.

Synchro-ballistic recording of detonation phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Critchfield, R.R.; Asay, B.W.; Bdzil, J.B.

1997-09-01

Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of themore » events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.« less

Insensitive fuze train for high explosives

DOEpatents

Cutting, Jack L.; Lee, Ronald S.; Von Holle, William G.

1994-01-01

A generic insensitive fuze train to initiate insensitive high explosives, such as PBXW-124. The insensitive fuze train uses a slapper foil to initiate sub-gram quantities of an explosive, such as HNS-IV or PETN. This small amount of explosive drives a larger metal slapper onto a booster charge of an insensitive explosive, such as UF-TATB. The booster charge initiates a larger charge of an explosive, such as LX-17, which in turn, initiates the insensitive high explosive, such as PBXW-124.

Insensitive fuze train for high explosives

DOEpatents

Cutting, J.L.; Lee, R.S.; Von Holle, W.G.

1994-01-04

A generic insensitive fuze train to initiate insensitive high explosives, such as PBXW-124 is described. The insensitive fuze train uses a slapper foil to initiate sub-gram quantities of an explosive, such as HNS-IV or PETN. This small amount of explosive drives a larger metal slapper onto a booster charge of an insensitive explosive, such as UF-TATB. The booster charge initiates a larger charge of an explosive, such as LX-17, which in turn, initiates the insensitive high explosive, such as PBXW-124. 3 figures.

Detonation propagation in annular arcs of condensed phase explosives

NASA Astrophysics Data System (ADS)

Ioannou, Eleftherios; Schoch, Stefan; Nikiforakis, Nikolaos; Michael, Louisa

2017-11-01

We present a numerical study of detonation propagation in unconfined explosive charges shaped as an annular arc (rib). Steady detonation in a straight charge propagates at constant speed, but when it enters an annular section, it goes through a transition phase and eventually reaches a new steady state of constant angular velocity. This study examines the speed of the detonation wave along the annular charge during the transition phase and at steady state, as well as its dependence on the dimensions of the annulus. The system is modeled using a recently proposed diffuse-interface formulation which allows for the representation of a two-phase explosive and of an additional inert material. The explosive considered is the polymer-bonded TATB-based LX-17 and is modeled using two Jones-Wilkins-Lee (JWL) equations of state and the ignition and growth reaction rate law. Results show that steady state speeds are in good agreement with experiment. In the transition phase, the evolution of outer detonation speed deviates from the exponential bounded growth function suggested by previous studies. We propose a new description of the transition phase which consists of two regimes. The first regime is caused by local effects at the outer edge of the annulus and leads to a dependence of the outer detonation speed on the angular position along the arc. The second regime is induced by effects originating from the inner edge of the annular charge and leads to the deceleration of the outer detonation until steady state is reached. The study concludes with a parametric study where the dependence of the steady state and the transition phase on the dimensions of the annulus is investigated.

30 CFR 57.8520 - Ventilation plan.

Code of Federal Regulations, 2014 CFR

2014-07-01

... depots, oil fuel storage depots, hoist rooms, compressors, battery charging stations and explosive... and booster fans including manufacturer's name, type, size, fan speed, blade setting, approximate... sketches showing how ventilation is accomplished in each typical type of working place including the...

30 CFR 57.8520 - Ventilation plan.

Code of Federal Regulations, 2011 CFR

2011-07-01

... depots, oil fuel storage depots, hoist rooms, compressors, battery charging stations and explosive... and booster fans including manufacturer's name, type, size, fan speed, blade setting, approximate... sketches showing how ventilation is accomplished in each typical type of working place including the...

30 CFR 57.8520 - Ventilation plan.

Code of Federal Regulations, 2012 CFR

2012-07-01

... depots, oil fuel storage depots, hoist rooms, compressors, battery charging stations and explosive... and booster fans including manufacturer's name, type, size, fan speed, blade setting, approximate... sketches showing how ventilation is accomplished in each typical type of working place including the...

30 CFR 57.8520 - Ventilation plan.

Code of Federal Regulations, 2013 CFR

2013-07-01

... depots, oil fuel storage depots, hoist rooms, compressors, battery charging stations and explosive... and booster fans including manufacturer's name, type, size, fan speed, blade setting, approximate... sketches showing how ventilation is accomplished in each typical type of working place including the...

Supernova Explosions Stay In Shape

NASA Astrophysics Data System (ADS)

2009-12-01

At a very early age, children learn how to classify objects according to their shape. Now, new research suggests studying the shape of the aftermath of supernovas may allow astronomers to do the same. A new study of images from NASA's Chandra X-ray Observatory on supernova remnants - the debris from exploded stars - shows that the symmetry of the remnants, or lack thereof, reveals how the star exploded. This is an important discovery because it shows that the remnants retain information about how the star exploded even though hundreds or thousands of years have passed. "It's almost like the supernova remnants have a 'memory' of the original explosion," said Laura Lopez of the University of California at Santa Cruz, who led the study. "This is the first time anyone has systematically compared the shape of these remnants in X-rays in this way." Astronomers sort supernovas into several categories, or "types", based on properties observed days after the explosion and which reflect very different physical mechanisms that cause stars to explode. But, since observed remnants of supernovas are leftover from explosions that occurred long ago, other methods are needed to accurately classify the original supernovas. Lopez and colleagues focused on the relatively young supernova remnants that exhibited strong X-ray emission from silicon ejected by the explosion so as to rule out the effects of interstellar matter surrounding the explosion. Their analysis showed that the X-ray images of the ejecta can be used to identify the way the star exploded. The team studied 17 supernova remnants both in the Milky Way galaxy and a neighboring galaxy, the Large Magellanic Cloud. For each of these remnants there is independent information about the type of supernova involved, based not on the shape of the remnant but, for example, on the elements observed in it. The researchers found that one type of supernova explosion - the so-called Type Ia - left behind relatively symmetric, circular remnants. This type of supernova is thought to be caused by a thermonuclear explosion of a white dwarf, and is often used by astronomers as "standard candles" for measuring cosmic distances. On the other hand, the remnants tied to the "core-collapse" supernova explosions were distinctly more asymmetric. This type of supernova occurs when a very massive, young star collapses onto itself and then explodes. "If we can link supernova remnants with the type of explosion", said co-author Enrico Ramirez-Ruiz, also of University of California, Santa Cruz, "then we can use that information in theoretical models to really help us nail down the details of how the supernovas went off." Models of core-collapse supernovas must include a way to reproduce the asymmetries measured in this work and models of Type Ia supernovas must produce the symmetric, circular remnants that have been observed. Out of the 17 supernova remnants sampled, ten were classified as the core-collapse variety, while the remaining seven of them were classified as Type Ia. One of these, a remnant known as SNR 0548-70.4, was a bit of an "oddball". This one was considered a Type Ia based on its chemical abundances, but Lopez finds it has the asymmetry of a core-collapse remnant. "We do have one mysterious object, but we think that is probably a Type Ia with an unusual orientation to our line of sight," said Lopez. "But we'll definitely be looking at that one again." While the supernova remnants in the Lopez sample were taken from the Milky Way and its close neighbor, it is possible this technique could be extended to remnants at even greater distances. For example, large, bright supernova remnants in the galaxy M33 could be included in future studies to determine the types of supernova that generated them. The paper describing these results appeared in the November 20 issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

29 CFR 1926.908 - Use of detonating cord.

Code of Federal Regulations, 2014 CFR

2014-07-01

... physical condition of the bore hole and stemming and the type of explosives used. (b) Detonating cord shall... cord extending out of a bore hole or from a charge shall be cut from the supply spool before loading the remainder of the bore hole or placing additional charges. (d) Detonating cord shall be handled and...

29 CFR 1926.908 - Use of detonating cord.

Code of Federal Regulations, 2011 CFR

2011-07-01

... physical condition of the bore hole and stemming and the type of explosives used. (b) Detonating cord shall... cord extending out of a bore hole or from a charge shall be cut from the supply spool before loading the remainder of the bore hole or placing additional charges. (d) Detonating cord shall be handled and...

Phenomenon of Energy Focusing in Explosive Systems which include High Modulus Elastic Elements

NASA Astrophysics Data System (ADS)

Balagansky, I.; Hokamoto, K.; Manikandan, P.; Matrosov, A.; Stadnichenko, I.; Miyoshi, H.

2009-06-01

The phenomenon was observed in a passive HE charge of cast Comp. B without cumulative shape under shock wave loading by explosion of an active HE charge through water after preliminary compression by a leading wave in silicon carbide insert. The phenomenon manifested itself as a hole in identification steel specimen with depth of about 10 mm and diameter of about 5 mm. Results of experiments on studying of conditions of implementation of this phenomenon for SEP and Comp. B are presented. For each HE a number of experiments has been executed at various length of silicon carbide insert. Presence or absence of a hole in the steel specimen was determined. Also a number of optical registrations of process in framing mode with record step of 1 μs have been executed. Digital video camera SHIMADZU HPV-1 was used for optical registration. Results of experiments testify that the phenomenon is reproduced both for SEP, and for Comp. B. Focusing process is observed in conditions close to critical conditions of transfer of a detonation from active to a passive HE charge.

GT0 Explosion Sources for IMS Infrasound Calibration: Charge Design and Yield Estimation from Near-source Observations

NASA Astrophysics Data System (ADS)

Gitterman, Y.; Hofstetter, R.

2014-03-01

Three large-scale on-surface explosions were conducted by the Geophysical Institute of Israel (GII) at the Sayarim Military Range, Negev desert, Israel: about 82 tons of strong high explosives in August 2009, and two explosions of about 10 and 100 tons of ANFO explosives in January 2011. It was a collaborative effort between Israel, CTBTO, USA and several European countries, with the main goal to provide fully controlled ground truth (GT0) infrasound sources, monitored by extensive observations, for calibration of International Monitoring System (IMS) infrasound stations in Europe, Middle East and Asia. In all shots, the explosives were assembled like a pyramid/hemisphere on dry desert alluvium, with a complicated explosion design, different from the ideal homogenous hemisphere used in similar experiments in the past. Strong boosters and an upward charge detonation scheme were applied to provide more energy radiated to the atmosphere. Under these conditions the evaluation of the actual explosion yield, an important source parameter, is crucial for the GT0 calibration experiment. Audio-visual, air-shock and acoustic records were utilized for interpretation of observed unique blast effects, and for determination of blast wave parameters suited for yield estimation and the associated relationships. High-pressure gauges were deployed at 100-600 m to record air-blast properties, evaluate the efficiency of the charge design and energy generation, and provide a reliable estimation of the charge yield. The yield estimators, based on empirical scaled relations for well-known basic air-blast parameters—the peak pressure, impulse and positive phase duration, as well as on the crater dimensions and seismic magnitudes, were analyzed. A novel empirical scaled relationship for the little-known secondary shock delay was developed, consistent for broad ranges of ANFO charges and distances, which facilitates using this stable and reliable air-blast parameter as a new potential yield estimator. The delay data of the 2009 shot with IMI explosives, characterized by much higher detonation velocity, are clearly separated from ANFO data, thus indicating a dependence on explosive type. This unique dual Sayarim explosion experiment (August 2009/January 2011), with the strongest GT0 sources since the establishment of the IMS network, clearly demonstrated the most favorable westward/eastward infrasound propagation up to 3,400/6,250 km according to appropriate summer/winter weather pattern and stratospheric wind directions, respectively, and thus verified empirically common models of infrasound propagation in the atmosphere.

Beam shaping for laser initiated optical primers

NASA Astrophysics Data System (ADS)

Lizotte, Todd E.

2008-08-01

Remington was one of the first firearm manufacturing companies to file a patent for laser initiated firearms, in 1969. Nearly 40 years later, the development of laser initiated firearms has not become a mainstream technology in the civilian market. Requiring a battery is definitely a short coming, so it is easy to see how such a concept would be problematic. Having a firearm operate reliably and the delivery of laser energy in an efficient manner to ignite the shock-sensitive explosive primer mixtures is a tall task indeed. There has been considerable research on optical element based methods of transferring or compressing laser energy to ignite primer charges, including windows, laser chip primers and various lens shaped windows to focus the laser energy. The focusing of laser light needs to achieve igniting temperatures upwards of >400°C. Many of the patent filings covering this type of technology discuss simple approaches where a single point of light might be sufficient to perform this task. Alternatively a multi-point method might provide better performance, especially for mission critical applications, such as precision military firearms. This paper covers initial design and performance test of the laser beam shaping optics to create simultaneous multiple point ignition locations and a circumferential intense ring for igniting primer charge compounds. A simple initial test of the ring beam shaping technique was evaluated on a standard large caliber primer to determine its effectiveness on igniting the primer material. Several tests were conducted to gauge the feasibility of laser beam shaping, including optic fabrication and mounting on a cartridge, optic durability and functional ignition performance. Initial data will be presented, including testing of optically elements and empirical primer ignition / burn analysis.

Lexan Linear Shaped Charge Holder with Magnets and Backing Plate

NASA Technical Reports Server (NTRS)

Maples, Matthew W.; Dutton, Maureen L.; Hacker, Scott C.; Dean, Richard J.; Kidd, Nicholas; Long, Chris; Hicks, Robert C.

2013-01-01

A method was developed for cutting a fabric structural member in an inflatable module, without damaging the internal structure of the module, using linear shaped charge. Lexan and magnets are used in a charge holder to precisely position the linear shaped charge over the desired cut area. Two types of charge holders have been designed, each with its own backing plate. One holder cuts fabric straps in the vertical configuration, and the other charge holder cuts fabric straps in the horizontal configuration.

Fuze for explosive magnetohydrodynamic generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, G.

1976-12-23

An apparatus is examined by which high explosive charges are propelled into and detonated at the center of an MHD-X generator. The high explosive charge units are engaged and propelled by a reciprocating ram device. Detonating in each instance is achieved by striking with a firing pin a detonator charge that is in register with a booster charge, the booster charge being in detonating communication with the high explosive charge. Various safety requirements are satisfied by a spring loaded slider operating in a channel transverse and adjacent to the booster charge. The slide retains the detonator charge out of registermore » with the booster charge until a safety pin that holds the slider in place is pulled by a lanyard attached between the reciprocating ram and the safety pin. Removal of the safety pin permits the detonator charge to slide into alignment with the booster charge. Firing pin actuation is initiated by the slider at the instant the detonator charge and the booster charge come into register.« less

Optical spectroscopy to study confined and semi-closed explosions of homogeneous and composite charges

NASA Astrophysics Data System (ADS)

Maiz, Lotfi; Trzciński, Waldemar A.; Paszula, Józef

2017-01-01

Confined and semi-closed explosions of new class of energetic composites as well as TNT and RDX charges were investigated using optical spectroscopy. These composites are considered as thermobarics when used in layered charges or enhanced blast explosives when pressed. Two methods to estimate fireball temperature histories of both homogeneous and metallized explosives from the spectroscopic data are also presented, compared and analyzed. Fireball temperature results of the charges detonated in a small explosion chamber under air and argon atmospheres, and detonated in a semi-closed bunker are presented and compared with theoretical ones calculated by a thermochemical code. Important conclusions about the fireball temperatures and the physical and chemical phenomena occurring after the detonation of homogeneous explosives and composite formulations are deduced.

Fluid-filled bomb-disrupting apparatus and method

DOEpatents

Cherry, Christopher R.

2001-01-01

An apparatus and method for disarming improvised bombs are disclosed. The apparatus comprises a fluid-filled bottle or container made of plastic or another soft material which contains a fixed or adjustable, preferably sheet explosive. The charge is fired centrally at its apex and can be adjusted to propel a fluid projectile that is broad or narrow, depending upon how it is set up. In one embodiment, the sheet explosive is adjustable so as to correlate the performance of the fluid projectile to the disarming needs for the improvised explosive device (IED). Common materials such as plastic water bottles or larger containers can be used, with the sheet explosive or other explosive material configured in a general chevron-shape to target the projectile toward the target. In another embodiment, a thin disk of metal is conformably mounted with the exterior of the container and radially aligned with the direction of fire of the fluid projectile. Depending on the configuration and the amount of explosive and fluid used, a projectile is fired at the target that has sufficient energy to penetrate rigid enclosures from fairly long stand-off and yet is focused enough to be targeted to specific portions of the IED for disablement.

Airblast Simulator Studies.

DTIC Science & Technology

1984-02-01

RAREFACTION WAVE ELIMINATOR CONSIDERATIONS 110 5.1 FLIP CALCULATIONS 110 5.2 A PASSIVE/ACTIVE RWE 118 6 DISTRIBUTED FUEL AIR EXPLOSIVES 120 REFERENCES 123 TA...conventional and distributed-charge fuel- air explosive charges used in a study of the utility of distributed charge FAE systems for blast simulation. The...limited investigation of distributed charge fuel air explosive configurations for blast simulator applications. During the course of this study

A hypervelocity launcher for simulated large fragment space debris impacts at 10 km/s

NASA Technical Reports Server (NTRS)

Tullos, R. J.; Gray, W. M.; Mullin, S. A.; Cour-Palais, B. G.

1989-01-01

The background, design, and testing of two explosive launchers for simulating large fragment space debris impacts are presented. The objective was to develop a launcher capable of launching one gram aluminum fragments at velocities of 10 km/s. The two launchers developed are based on modified versions of an explosive shaped charge, common in many military weapons. One launcher design has yielded a stable fragment launch of approximately one gram of aluminum at 8.93 km/s velocity. The other design yielded velocities in excess of 10 km/s, but failed to produce a cohesive fragment launch. This work is ongoing, and future plans are given.

Wave Pattern Peculiarities of Different Types of Explosions Conducted at Semipalatinsk Test Site

NASA Astrophysics Data System (ADS)

Sokolova, Inna

2014-05-01

The historical seismograms of the explosions conducted at the STS in 1949 - 1989 are of great interest for the researchers in the field of monitoring. Large number of air (86), surface (30) and underground nuclear explosions were conducted here in boreholes and tunnels (340). In addition to nuclear explosions, large chemical explosions were conducted at the Test Site. It is known that tectonic earthquakes occur on the Test Site territory and near it. Since 2005 the Institute of Geophysical Researches conducts works on digitizing the historical seismograms of nuclear explosions. Currently, the database contains more than 6000 digitized seismograms of nuclear explosions used for investigative monitoring tasks, major part of them (4000) are events from the STS region. Dynamic parameters of records of air, surface and underground nuclear explosions, as well as large chemical explosions with compact charge laying were investigated for seismic stations located on the territory of Kazakhstan using digitized records of the STS events. In addition, the comparison between salvo wave pattern and single explosions was conducted. The records of permanent and temporary seismic stations (epicentral distances range 100 - 800 km) were used for the investigations. Explosions spectra were analyzed, specific features of each class of events were found. The seismograms analysis shows that the wave pattern depends significantly on the explosion site and on the source type.

Computational Investigation of In-Flight Temperature in Shaped Charge Jets and Explosively Formed Penetrators

NASA Astrophysics Data System (ADS)

Sable, Peter; Helminiak, Nathaniel; Harstad, Eric; Gullerud, Arne; Hollenshead, Jeromy; Hertel, Eugene; Sandia National Laboratories Collaboration; Marquette University Collaboration

2017-06-01

With the increasing use of hydrocodes in modeling and system design, experimental benchmarking of software has never been more important. While this has been a large area of focus since the inception of computational design, comparisons with temperature data are sparse due to experimental limitations. A novel temperature measurement technique, magnetic diffusion analysis, has enabled the acquisition of in-flight temperature measurements of hyper velocity projectiles. Using this, an AC-14 bare shaped charge and an LX-14 EFP, both with copper linings, were simulated using CTH to benchmark temperature against experimental results. Particular attention was given to the slug temperature profiles after separation, and the effect of varying equation-of-state and strength models. Simulations are in agreement with experimental, attaining better than 2% error between observed shaped charge temperatures. This varied notably depending on the strength model used. Similar observations were made simulating the EFP case, with a minimum 4% deviation. Jet structures compare well with radiographic images and are consistent with ALEGRA simulations previously conducted. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Analysis of Computational Models of Shaped Charges for Jet Formation and Penetration

NASA Astrophysics Data System (ADS)

Haefner, Jonah; Ferguson, Jim

2016-11-01

Shaped charges came into use during the Second World War demonstrating the immense penetration power of explosively formed projectiles and since has become a tool used by nearly every nation in the world. Penetration is critically dependent on how the metal liner is collapsed into a jet. The theory of jet formation has been studied in depth since the late 1940s, based on simple models that neglect the strength and compressibility of the metal liner. Although attempts have been made to improve these models, simplifying assumptions limit the understanding of how the material properties affect the jet formation. With a wide range of material and strength models available for simulation, a validation study was necessary to guide code users in choosing models for shaped charge simulations. Using PAGOSA, a finite-volume Eulerian hydrocode designed to model hypervelocity materials and strong shock waves developed by Los Alamos National Laboratory, and experimental data, we investigated the effects of various equations of state and material strength models on jet formation and penetration of a steel target. Comparing PAGOSA simulations against modern experimental data, we analyzed the strengths and weaknesses of available computational models. LA-UR-16-25639 Los Alamos National Laboratory.

Transition-Metal-Doped p-Type ZnO Nanoparticle-Based Sensory Array for Instant Discrimination of Explosive Vapors.

PubMed

Qu, Jiang; Ge, Yuru; Zu, Baiyi; Li, Yuxiang; Dou, Xincun

2016-03-09

The development of portable, real-time, and cheap platforms to monitor ultratrace levels of explosives is of great urgence and importance due to the threat of terrorism attacks and the need for homeland security. However, most of the previous chemiresistor sensors for explosive detection are suffering from limited responses and long response time. Here, a transition-metal-doping method is presented to remarkably promote the quantity of the surface defect states and to significantly reduce the charge transfer distance by creating a local charge reservoir layer. Thus, the sensor response is greatly enhanced and the response time is remarkably shortened. The resulting sensory array can not only detect military explosives, such as, TNT, DNT, PNT, PA, and RDX with high response, but also can fully distinguish some of the improvised explosive vapors, such as AN and urea, due to the huge response reaching to 100%. Furthermore, this sensory array can discriminate ppb-level TNT and ppt-level RDX from structurally similar and high-concentration interfering aromatic gases in less than 12 s. Through comparison with the previously reported chemiresistor or Schottky sensors for explosive detection, the present transition-metal-doping method resulting ZnO sensor stands out and undoubtedly challenges the best. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Investigation of the Material Hazard of Some Insensitive High Explosives

DTIC Science & Technology

1991-07-01

251 HNSM ypel 0go 7 54 Type g 9o. 12 NO 0-90’ 3-5 75-104’ NQ (picite) 100- 106 ’ 1-2 > 320, 70-100’ OphekaD 120-180 1 DNVF 90’ 19.8 18k, 76’ ADNOF 60 13.0...and Bocksteiner, G. (1989). Insensitive polymer bonded main charge explosive PBXN -107: Binder and formulation studio (MRL Technical Report MRL-TR-89

Magnetically insulated coaxial vacuum diode with partial space-charge-limited explosive emission from edge-type cathode

NASA Astrophysics Data System (ADS)

Belomyttsev, S. Ya.; Rostov, V. V.; Romanchenko, I. V.; Shunailov, S. A.; Kolomiets, M. D.; Mesyats, G. A.; Sharypov, K. A.; Shpak, V. G.; Ulmaskulov, M. R.; Yalandin, M. I.

2016-01-01

The vacuum current associated with any type of electron emission for arbitrary configuration of the diode depends on the combination of the applied electric field and vacuum space charge (VSC) field created by the current. Such fundamental statement should give very close links between the diode current and the normalized cathode field θ which has been introduced by Forbes in 2008 for planar diodes as a reduction in the cathode surface field: θ = field-with/field-without VSC. This article reports the universal approximation of the type of cos(πθ/2) that is the ratio of the actual current and the fully space-charge-limited current. Also, the theoretical treatment and the experimental method of determination of the dynamic emissive characteristics of the macroscopic explosive emission from edge-type cathodes in the coaxial diode are developed. The experimental results obtained with a picosecond time reference between the cathode voltage and the onset of the high-current electron beam exhibit a good coincidence with the theoretical predictions. The presented methods enable the analysis of a real-time-resolved dynamics associated with the dense, magnetized electron beam formation, acceleration and drift motion, including kinematic effects and the phase-stable excitation of high-power microwave oscillators.

Magnetically insulated coaxial vacuum diode with partial space-charge-limited explosive emission from edge-type cathode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belomyttsev, S. Ya.; Rostov, V. V.; Romanchenko, I. V.

2016-01-14

The vacuum current associated with any type of electron emission for arbitrary configuration of the diode depends on the combination of the applied electric field and vacuum space charge (VSC) field created by the current. Such fundamental statement should give very close links between the diode current and the normalized cathode field θ which has been introduced by Forbes in 2008 for planar diodes as a reduction in the cathode surface field: θ = field-with/field-without VSC. This article reports the universal approximation of the type of cos(πθ/2) that is the ratio of the actual current and the fully space-charge-limited current. Also, themore » theoretical treatment and the experimental method of determination of the dynamic emissive characteristics of the macroscopic explosive emission from edge-type cathodes in the coaxial diode are developed. The experimental results obtained with a picosecond time reference between the cathode voltage and the onset of the high-current electron beam exhibit a good coincidence with the theoretical predictions. The presented methods enable the analysis of a real-time-resolved dynamics associated with the dense, magnetized electron beam formation, acceleration and drift motion, including kinematic effects and the phase-stable excitation of high-power microwave oscillators.« less

Combined use of direct analysis in real-time/Orbitrap mass spectrometry and micro-Raman spectroscopy for the comprehensive characterization of real explosive samples.

PubMed

Bridoux, Maxime C; Schwarzenberg, Adrián; Schramm, Sébastien; Cole, Richard B

2016-08-01

Direct Analysis in Real Time (DART™) high-resolution Orbitrap™ mass spectrometry (HRMS) in combination with Raman microscopy was used for the detailed molecular level characterization of explosives including not only the charge but also the complex matrix of binders, plasticizers, polymers, and other possible organic additives. A total of 15 defused military weapons including grenades, mines, rockets, submunitions, and mortars were examined. Swabs and wipes were used to collect trace (residual) amounts of explosives and their organic constituents from the defused military weapons and micrometer-size explosive particles were transferred using a vacuum suction-impact collection device (vacuum impactor) from wipe and swap samples to an impaction plate made of carbon. The particles deposited on the carbon plate were then characterized using micro-Raman spectroscopy followed by DART-HRMS providing fingerprint signatures of orthogonal nature. The optical microscope of the micro-Raman spectrometer was first used to localize and characterize the explosive charge on the impaction plate which was then targeted for identification by DART-HRMS analysis in both the negative and positive modes. Raman spectra of the explosives TNT, RDX and PETN were acquired from micrometer size particles and characterized by the presence of their characteristic Raman bands obtained directly at the surface of the impaction plate nondestructively without further sample preparation. Negative mode DART-HRMS confirmed the types of charges contained in the weapons (mainly TNT, RDX, HMX, and PETN; either as individual components or as mixtures). These energetic compounds were mainly detected as deprotonated species [M-H](-), or as adduct [M + (35)Cl](-), [M + (37)Cl](-), or [M + NO3](-) anions. Chloride adducts were promoted in the heated DART reagent gas by adding chloroform vapors to the helium stream using an "in-house" delivery method. When the polarity was switched to positive mode, DART-HRMS revealed a very complex distribution of polymeric binders (mainly polyethylene glycols and polypropylene glycols), plasticizers (e.g., dioctyl sebacate, tributyl phosphate), as well as wax-like compounds whose structural features could not be precisely assigned. In positive mode, compounds were identified either as protonated molecules or ammonium adduct species. These results clearly demonstrate the complementarity of micro-Raman microscopy combined with DART-MS. The former technique provides structural information on the type of explosives present at the surface of the sample, whereas the latter provides not only a confirmation of the nature of the explosive charge but also useful additional information regarding the nature of the complex organic matrix of binders, plasticizers, polymers, oils, and potentially other organic additives and contaminants present in the sample. Combining these two techniques provides a powerful tool for the screening, comprehensive characterization, and differentiation of particulate explosive samples for forensic sciences and homeland security applications. Graphical Abstract Comprehensive characterization of explosive particles collected from swipe samples by micro-Raman and DART™-HRMS.

Testing of Confining Pressure Impacton Explosion Energy of Explosive Materials

NASA Astrophysics Data System (ADS)

Drzewiecki, Jan; Myszkowski, Jacek; Pytlik, Andrzej; Pytlik, Mateusz

2017-06-01

This paper presents the results of testing the explosion effects of two explosive charges placed in an environment with specified values of confining pressure. The aim of this study is to determine the impact of variable environmental conditions on the suitability of particular explosives for their use in the prevention of natural hazards in hard coal mining. The research results will contribute to improving the efficiency of currently adopted technologies of natural hazard prevention and aid in raising the level of occupational safety. To carry out the subject matter measurements, a special test stand was constructed which allows the value of the initial pressure inside the chamber, which constitutes its integral part, to be altered before the detonation of the charge being tested. The obtained characteristics of the pressure changes during the explosion of the analysed charge helped to identify the work (energy) which was produced during the process. The test results are a valuable source of information, opening up new possibilities for the use of explosives, the development of innovative solutions for the construction of explosive charges and their initiation.

Dual initiation strip charge apparatus and methods for making and implementing the same

DOEpatents

Jakaboski, Juan-Carlos [Albuquerque, NM; Todd,; Steven, N [Rio Rancho, NM; Polisar, Stephen [Albuquerque, NM; Hughs, Chance [Tijeras, NM

2011-03-22

A Dual Initiation Strip Charge (DISC) apparatus is initiated by a single initiation source and detonates a strip of explosive charge at two separate contacts. The reflection of explosively induced stresses meet and create a fracture and breach a target along a generally single fracture contour and produce generally fragment-free scattering and no spallation. Methods for making and implementing a DISC apparatus provide numerous advantages over previous methods of creating explosive charges by utilizing steps for rapid prototyping; by implementing efficient steps and designs for metering consistent, repeatable, and controlled amount of high explosive; and by utilizing readily available materials.

A Numerical Study of Projectile Impact on Explosives

DTIC Science & Technology

1977-04-01

Whitbreac5 and Dewey and Slade6 performed and analyzed this type of test for charges which were unconfined or confined only on the impacted surface...With such charges one observes either that the charge detorxates or is shattered and the result is recorded as no reaction. Dewey and Slade, and Brown...detonations. At the onset of this work, we expectrd that plastic 5. S. Brown and E. Whitbread, Les Ondes de Detonation, 1961. 6. J. Dewey and D. Slade

Explosives for Lunar Seismic Profiling Experiment (LSPE)

NASA Technical Reports Server (NTRS)

1973-01-01

Explosive charges of various sizes were investigated for use in lunar seismic studies. Program logistics, and the specifications for procurement of bulk explosives are described. The differential analysis, thermal properties, and detonation velocity measurements on HNS/Teflon 7C 90/10 are reported along with the field tests of the hardware. It is concluded that nearly all large explosive charges crack after fabrication, from aging or thermal shock. The cracks do not affect the safety, or reliability of the explosives.

Gulf War Illnesses: DOD’s Conclusions about U.S. Troops’ Exposure Cannot be Adequately Supported

DTIC Science & Technology

2004-06-01

well fires, fumes from jet fuel , fumes from burning jet fuel in tents, petroleum in drinking water, depleted uranium munitions, smoking, alcohol use...Explosive 31 Figure 6: Boundary Layer Characteristics 32 Figure 7: Three Types of Plume Geometry 33 Figure 8: The Impact of Nocturnal Jets on a...ignited by thermite grenades—alone and with the addition of diesel fuel —as well as by fused initiation of the burster explosive charge. According to

Review of sonic-boom simulation devices and techniques.

NASA Technical Reports Server (NTRS)

Edge, P. M., Jr.; Hubbard, H. H.

1972-01-01

Research on aircraft-generated sonic booms has led to the development of special techniques to generate controlled sonic-boom-type disturbances without the complications and expense of supersonic flight operations. This paper contains brief descriptions of several of these techniques along with the significant hardware items involved and indicates the advantages and disadvantages of each in research applications. Included are wind tunnels, ballistic ranges, spark discharges, piston phones, shock tubes, high-speed valve systems, and shaped explosive charges. Specialized applications include sonic-boom generation and propagation studies and the responses of structures, terrain, people, and animals. Situations for which simulators are applicable are shown to include both small-scale and large-scale laboratory tests and full-scale field tests. Although no one approach to simulation is ideal, the various techniques available generally complement each other to provide desired capability for a broad range of sonic-boom studies.

An Investigation of Secondary Jetting Phenomena ’Hyperjet’ Shaped Charge.

DTIC Science & Technology

1982-08-01

Hyperjet design. Primarily flash x ray techniques would be used to measure jet velocities resulting from secon- dary collisions. A formal report would be...the liner in time: a- X 2 (t-t1 ) 2 Ph __ Eqns. 2 Where a = Liner acceleration of some point in the liner Pcj = Chapman-Jouget explosive pressure Ps...liner. Since liner accerleration of any point along the liner is known, it is therefore possible to describe the governing equation of motion as: d2R = a

GAP/CL-20-Based Compound Explosive: A New Booster Formulation Used in a Small-Sized Initiation Network

NASA Astrophysics Data System (ADS)

Yanju, Wei; Jingyu, Wang; Chongwei, An; Hequn, Li; Xiaomu, Wen; Binshuo, Yu

2017-01-01

With ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and glycidyl azide polymer (GAP) as the solid filler and binder, respectively, GAP/CL-20-based compound explosives were designed and prepared. Using micro injection charge technology, the compound explosives were packed into small grooves to explore their application in a small-sized initiation network. The detonation reliability, detonation velocity, mechanical sensitivity, shock sensitivity, and brisance of the explosive were measured and analyzed. The results show that when the solid content of CL-20 is 82 wt%, the explosive charged in the groove has a smooth surface from a macroscopic view. From a microscopic view, a coarse surface is bonded with many CL-20 particles by GAP binder. The GAP/CL-20-based explosive charge successfully generates detonation waves in a groove larger than 0.6 mm × 0.6 mm. When the charge density in the groove is 1.68 g.cm-3 (90% theoretical maximum density), the detonation velocity reaches 7,290 m.s-1. Moreover, this kind of explosive is characterized by low impact and shock sensitivity.

On the high fidelity simulation of chemical explosions and their interaction with solid particle clouds

NASA Astrophysics Data System (ADS)

Balakrishnan, Kaushik

The flow field behind chemical explosions in multiphase environments is investigated using a robust, state-of-the-art simulation strategy that accounts for the thermodynamics, gas dynamics and fluid mechanics of relevance to the problem. Focus is laid on the investigation of blast wave propagation, growth of hydrodynamic instabilities behind explosive blasts, the mixing aspects behind explosions, the effects of afterburn and its quantification, and the role played by solid particles in these phenomena. In particular, the confluence and interplay of these different physical phenomena are explored from a fundamental perspective, and applied to the problem of chemical explosions. A solid phase solver suited for the study of high-speed, two-phase flows has been developed and validated. This solver accounts for the inter-phase mass, momentum and energy transfer through empirical laws, and ensures two-way coupling between the two phases, viz. solid particles and gas. For dense flow fields, i.e., when the solid volume fraction becomes non-negligible (˜60%), the finite volume method with a Godunov type shock-capturing scheme requires modifications to account for volume fraction gradients during the computation of cell interface gas fluxes. To this end, the simulation methodology is extended with the formulation of an Eulerian gas, Lagrangian solid approach, thereby ensuring that the so developed two-phase simulation strategy can be applied for both flow conditions, dilute and dense alike. Moreover, under dense loading conditions the solid particles inevitably collide, which is accounted for in the current research effort with the use of an empirical collision/contact model from literature. Furthermore, the post-detonation flow field consists of gases under extreme temperature and pressure conditions, necessitating the use of real gas equations of state in the multiphase model. This overall simulation strategy is then extended to the investigation of chemical explosions in multiphase environments, with emphasis on the study of hydrodynamic instability growth, mixing, afterburn effects ensuing from the process, particle ignition and combustion (if reactive), dispersion, and their interaction with the vortices in the mixing layer. The post-detonation behavior of heterogeneous explosives is addressed by using three parts to the investigation. In the first part, only one-dimensional effects are considered, with the goal to assess the presently developed dense two-phase formulation. The total deliverable impulsive loading from heterogeneous explosive charges containing inert steel particles is estimated for a suite of operating parameters and compared, and it is demonstrated that heterogeneous explosive charges deliver a higher near-field impulse than homogeneous explosive charges containing the same mass of the high explosive. In the second part, three-dimensional effects such as hydrodynamic instabilities are accounted for, with the focus on characterizing the mixing layer ensuing from the detonation of heterogeneous explosive charges containing inert steel particles. It is shown that particles introduce significant amounts of hydrodynamic instabilities in the mixing layer, resulting in additional physical phenomena that play a prominent role in the flow features. In particular, the fluctuation intensities, fireball size and growth rates are augmented for heterogeneous explosions vis-a-vis homogeneous explosions, thereby demonstrating that solid particles enhance the perturbation intensities in the flow. In the third part of the investigation of heterogeneous explosions, dense, aluminized explosions are considered, and the particles are observed to burn in two phases, with an initial quenching due to the rarefaction wave, and a final quenching outside the fireball. Due to faster response time scales, smaller particles are observed to heat and accelerate more during early times, and also cool and decelerate more at late times, compared to counterpart larger particle sizes. Furthermore, the average particle velocities at late times are observed to be independent of the initial solid volume fraction in the explosive charge, as the particles eventually reach an equilibrium with the local gas. These studies have provided some crucial insights to the flow physics of dense, aluminized explosives. (Abstract shortened by UMI.)

Effects of charge design features on parameters of acoustic and seismic waves and cratering, for SMR chemical surface explosions

NASA Astrophysics Data System (ADS)

Gitterman, Y.

2012-04-01

A series of experimental on-surface shots was designed and conducted by the Geophysical Institute of Israel at Sayarim Military Range (SMR) in Negev desert, including two large calibration explosions: about 82 tons of strong IMI explosives in August 2009, and about 100 tons of ANFO explosives in January 2011. It was a collaborative effort between Israel, CTBTO, USA and several European countries, with the main goal to provide fully controlled ground truth (GT0) infrasound sources in different weather/wind conditions, for calibration of IMS infrasound stations in Europe, Middle East and Asia. Strong boosters and the upward charge detonation scheme were applied to provide a reduced energy release to the ground and an enlarged energy radiation to the atmosphere, producing enhanced infrasound signals, for better observation at far-regional stations. The following observations and results indicate on the required explosives energy partition for this charge design: 1) crater size and local seismic (duration) magnitudes were found smaller than expected for these large surface explosions; 2) small test shots of the same charge (1 ton) conducted at SMR with different detonation directions showed clearly lower seismic amplitudes/energy and smaller crater size for the upward detonation; 3) many infrasound stations at local and regional distances showed higher than expected peak amplitudes, even after application of a wind-correction procedure. For the large-scale explosions, high-pressure gauges were deployed at 100-600 m to record air-blast properties, evaluate the efficiency of the charge design and energy generation, and provide a reliable estimation of the charge yield. Empirical relations for air-blast parameters - peak pressure, impulse and the Secondary Shock (SS) time delay - depending on distance, were developed and analyzed. The parameters, scaled by the cubic root of estimated TNT equivalent charges, were found consistent for all analyzed explosions, except of SS time delays clearly separated for the shot of IMI explosives (characterized by much higher detonation velocity than ANFO). Additionally acoustic records at close distances from WSMR explosions Distant Image (2440 tons of ANFO) and Minor Uncle (2725 tons of ANFO) were used to extend the charge and distance range for the SS delay scaled relationship, that showed consistency with SMR ANFO shots. The developed specific charge design contributed to the success of this unique dual Sayarim explosion experiment, providing the strongest GT0 sources since the establishment of the IMS network, that demonstrated clearly the most favorable westward/ eastward infrasound propagation up to 3400/6250 km according to appropriate summer/winter weather pattern and stratospheric wind directions, respectively, and thus verified empirically common models of infrasound propagation in the atmosphere. The research was supported by the CTBTO, Vienna, and the Israel Ministry of Immigrant Absorption.

Modelling and Testing of Blast Effect On the Structures

NASA Astrophysics Data System (ADS)

Figuli, Lucia; Jangl, Štefan; Papán, Daniel

2016-10-01

As a blasting agent in the blasting and mining engineering, has been using one of so called new generation of explosives which offer greater flexibility in their range and application, and such explosive is ANFO. It is type of explosive consists of an oxidiser and a fuel (ammonium nitrate and fuel oil). One of such ANFO explosives which are industrially made in Slovakia is POLONIT. The explosive is a mixture of ammonium nitrate, methyl esters of higher fatty acids, vegetable oil and red dye. The paper deals with the analysis of structure subjected to the blast load created by the explosion of POLONIT charge. First part of paper is describing behaviour and characteristic of blast wave generated from the blast (detonation characteristics, physical characteristics, time-history diagram etc.) and the second part presents the behaviour of such loaded structures, because of the analysis of such dynamical loaded structure is required knowing the parameters of blast wave, its effect on structure and the tools for the solution of dynamic analysis. The real field tests of three different weight of charges and two different structures were done. The explosive POLONIT was used together with 25 g of ignition explosive PLNp10. Analytical and numerical model of blast loaded structure is compared with the results obtained from the field tests (is compared with the corresponding experimental accelerations). For the modelling structures were approximated as a one-degree system of freedom (SDOF), where the blast wave was estimated with linear decay and exponential decay using positive and negative phase of blast wave. Numerical solution of the steel beam dynamic response was performed via FEM (Finite Element Method) using standard software Visual FEA.

Surface waves generated by shallow underwater explosions

NASA Technical Reports Server (NTRS)

Falade, A.; Holt, M.

1978-01-01

Surface water waves generated by surface and near surface point explosions are calculated. Taking the impulse distribution imparted at the water surface by the explosion as the overriding mechanism for transferring energy of the explosive to surface wave motion, the linearized theory of Kranzer and Keller is used to obtain the wave displacement in the far field. The impulse distribution is obtained by integrating the pressure wave over an appropriate time interval on a horizontal surface just beneath the undisturbed water surface. For surface explosions, a modified form of the similarity method first used by Collins and Holt is used to obtain the flow field. In the case of submerged explosions, the flow field is estimated by making necessary modifications to Sedov's similarity solution to account for the venting that accompanies the interaction of the leading (blast) wave with the ocean surface. Surface waves generated by a charge at six depths of placement (0.15 m, 0.30 m, 0.61 m, 0.91 m, 1.37 m, 3.05 m) are considered in addition to surface explosions. The results seem to support the existence of an upper critical depth phenomenon (of the type already established for chemical explosions) for point (nuclear) explosions.

Modelling blast induced damage from a fully coupled explosive charge

PubMed Central

Onederra, Italo A.; Furtney, Jason K.; Sellers, Ewan; Iverson, Stephen

2015-01-01

This paper presents one of the latest developments in the blasting engineering modelling field—the Hybrid Stress Blasting Model (HSBM). HSBM includes a rock breakage engine to model detonation, wave propagation, rock fragmentation, and muck pile formation. Results from two controlled blasting experiments were used to evaluate the code’s ability to predict the extent of damage. Results indicate that the code is capable of adequately predicting both the extent and shape of the damage zone associated with the influence of point-of-initiation and free-face boundary conditions. Radial fractures extending towards a free face are apparent in the modelling output and matched those mapped after the experiment. In the stage 2 validation experiment, the maximum extent of visible damage was of the order of 1.45 m for the fully coupled 38-mm emulsion charge. Peak radial velocities were predicted within a relative difference of only 1.59% at the nearest history point at 0.3 m from the explosive charge. Discrepancies were larger further away from the charge, with relative differences of −22.4% and −42.9% at distances of 0.46 m and 0.61 m, respectively, meaning that the model overestimated particle velocities at these distances. This attenuation deficiency in the modelling produced an overestimation of the damage zone at the corner of the block due to excessive stress reflections. The extent of visible damage in the immediate vicinity of the blasthole adequately matched the measurements. PMID:26412978

The use of explosives by the US Antarctic Program. Environmental report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ensminger, J.T.; Blasing, T.J.

1995-06-01

This report was prepared to assist principal investigators and others in complying with NEPA and the protocol on environmental protection to the Antarctic Treaty. Research activities and associated support operations in Antarctica sometimes require use of explosives. This report evaluates potential environmental impacts associated with such activities and possible methods for mitigating those impacts. The greatest single use of explosives, and the only type of blasting that will occur on the Polar Plateau (an exception is the rare use of explosives to cave in dangerous ice for safety reasons), is for seismic surveys. The charges for these are small-scale, aremore » placed in or on the snow or ice, are distributed linearly over long distances, and present no potential impacts to soil or geological substrata. Impacts from those would be less than minor or transitory. Wherever possible, blasting holes in sea ice will be replaced by drilling by auger or melting. Other uses of explosives, such as in geologic research and construction, are discussed.« less

Explosive-residue compounds resulting from snow avalanche control in the Wasatch Mountains of Utah

USGS Publications Warehouse

Naftz, David L.; Kanagy, Leslie K.; Susong, David D.; Wydoski, Duane S.; Kanagy, Christopher J.

2003-01-01

A snow avalanche is a powerful force of nature that can play a significant role in developing mountain landscapes (Perla and Martinelli, 1975). More importantly, loss of life can occur when people are caught in the path of snow avalanches (Grossman, 1999). Increasing winter recreation, including skiing, snowboarding, snowmobiling, snowshoeing, and climbing in mountainous areas, has increased the likelihood of people encountering snow avalanches (fig. 1). Explosives are used by most ski areas and State highway departments throughout the Western United States to control the release of snow avalanches, thus minimizing the loss of human life during winter recreation and highway travel (fig. 2).Common explosives used for snow avalanche control include trinitrotoluene (TNT), pentaerythritoltetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), tetrytol, ammonium nitrate, and nitroglycerin (Perla and Martinelli, 1975). During and after snowfall or wind loading of potential avalanche slopes, ski patrollers and Utah Department of Transportation personnel deliver explosive charges onto predetermined targets to artificially release snow avalanches, thereby rendering the slope safer for winter activities. Explosives can be thrown by hand onto target zones or shot from cannons for more remote delivery of explosive charges. Hand-delivered charges typically contain about 2 pounds of TNT or its equivalent (Perla and Martinelli, 1975).Depending on the size of the ski area, acreage of potential avalanche terrain, and weather conditions, the annual quantity of explosives used during a season of snow avalanche control can be substantial. For example, the three ski areas of Alta, Snowbird, and Brighton, plus the Utah Department of Transportation, may use as many as 11,200 hand charges per year (Wasatch Powderbird Guides, unpub. data, 1999) for snow avalanche control in Big and Little Cottonwood Canyons (fig. 3). If each charge is assumed to weigh 2 pounds, this equates to about 22,400 pounds of explosive hand charges per year. In addition, 2,240 to 3,160 Avalauncher rounds and 626 to 958 military artillery rounds (explosive mass not specified) are used each year by the three ski areas and the Utah Department of Transportation for snow avalanche control in Big and Little Cottonwood Canyons (Wasatch Powderbird Guides, unpub. data, 1999). The other ski area in Big Cottonwood Canyon, Brighton, uses about 2,000 pounds of explosives per year for snow avalanche control (Michele Weidner, Cirrus Ecological Solutions consultant, written commun., 2001).

Supernova Light Curves and Spectra from Two Different Codes: Supernu and Phoenix

NASA Astrophysics Data System (ADS)

Van Rossum, Daniel R; Wollaeger, Ryan T

2014-08-01

The observed similarities between light curve shapes from Type Ia supernovae, and in particular the correlation of light curve shape and brightness, have been actively studied for more than two decades. In recent years, hydronamic simulations of white dwarf explosions have advanced greatly, and multiple mechanisms that could potentially produce Type Ia supernovae have been explored in detail. The question which of the proposed mechanisms is (or are) possibly realized in nature remains challenging to answer, but detailed synthetic light curves and spectra from explosion simulations are very helpful and important guidelines towards answering this question.We present results from a newly developed radiation transport code, Supernu. Supernu solves the supernova radiation transfer problem uses a novel technique based on a hybrid between Implicit Monte Carlo and Discrete Diffusion Monte Carlo. This technique enhances the efficiency with respect to traditional implicit monte carlo codes and thus lends itself perfectly for multi-dimensional simulations. We show direct comparisons of light curves and spectra from Type Ia simulations with Supernu versus the legacy Phoenix code.

Air Blast Calculations

DTIC Science & Technology

2013-07-01

composition C-4 (C4), a polymer-bonded explosive (PBXN-109), and nitromethane (NM). Each charge diameter (CD) is assumed to be 17.46 cm (equivalent to a 10-lb... explosive detonates, the rapid expansion of reaction gases generates a shock wave that propagates into the surrounding medium. The pressure history at a...spherical explosive charge suspended in air. A comparison of the results obtained using CTH are made to ones generated using the Friedlander

Coulomb explosion of uniformly charged spheroids

NASA Astrophysics Data System (ADS)

Grech, M.; Nuter, R.; Mikaberidze, A.; di Cintio, P.; Gremillet, L.; Lefebvre, E.; Saalmann, U.; Rost, J. M.; Skupin, S.

2011-11-01

A simple, semianalytical model is proposed for nonrelativistic Coulomb explosion of a uniformly charged spheroid. This model allows us to derive the time-dependent particle energy distributions. Simple expressions are also given for the characteristic explosion time and maximum particle energies in the limits of extreme prolate and oblate spheroids as well as for the sphere. Results of particle simulations are found to be in remarkably good agreement with the model.

Initiation disruptor systems and methods of initiation disruption

DOEpatents

Baum, Dennis W

2014-09-23

A system that may be used as an initiation disruption system (IDS) according to one embodiment includes an explosive charge; a plurality of particles in a layer at least partially surrounding the explosive charge; and a fire suppressant adjacent the plurality of particles. A method for disabling an object according to one embodiment includes placing the system as recited above near an object; and causing the explosive charge to initiate, thereby applying mechanical loading to the object such that the object becomes disabled. Additional systems and methods are also presented. A device according to another embodiment includes a plurality of particles bound by a binder thereby defining a sidewall having an interior for receiving an explosive; and a fire suppressant adjacent the plurality of particles and binder. Additional systems and methods are also presented.

Observations of SN 2015F Suggest a Correlation between the Intrinsic Luminosity of Type Ia Supernovae and the Shape of Their Light Curves >900 Days after Explosion

NASA Astrophysics Data System (ADS)

Graur, Or; Zurek, David R.; Rest, Armin; Seitenzahl, Ivo R.; Shappee, Benjamin J.; Fisher, Robert; Guillochon, James; Shara, Michael M.; Riess, Adam G.

2018-06-01

The late-time light curves of Type Ia supernovae (SNe Ia), observed >900 days after explosion, present the possibility of a new diagnostic for SN Ia progenitor and explosion models. First, however, we must discover what physical process (or processes) leads to the slow-down of the light curve relative to a pure 56Co decay, as observed in SNe 2011fe, 2012cg, and 2014J. We present Hubble Space Telescope observations of SN 2015F, taken ≈600–1040 days past maximum light. Unlike those of the three other SNe Ia, the light curve of SN 2015F remains consistent with being powered solely by the radioactive decay of 56Co. We fit the light curves of these four SNe Ia in a consistent manner and measure possible correlations between the light-curve stretch—a proxy for the intrinsic luminosity of the SN—and the parameters of the physical model used in the fit. We propose a new, late-time Phillips-like correlation between the stretch of the SNe and the shape of their late-time light curves, which we parameterize as the difference between their pseudo-bolometric luminosities at 600 and 900 days: ΔL 900 = log(L 600/L 900). Our analysis is based on only four SNe, so a larger sample is required to test the validity of this correlation. If true, this model-independent correlation provides a new way to test which physical process lies behind the slow-down of SN Ia light curves >900 days after explosion, and, ultimately, fresh constraints on the various SN Ia progenitor and explosion models.

Effects of combustibles on internal quasi-static loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandoval, N.R.; Hokanson, J.C.; Esparza, E.D.

1984-08-01

The phenomenon of quasi-static pressure enhancement produced when combustible materials are placed near HE sources has been recently discovered. The effects of placing solid and liquid combustible materials near detonating explosives on internal blast loading was measured during tests conducted in a one-eighth scale model of a containment structure. In many cases, dramatic increases in gas pressures resulted. Principal conclusions of this study are: combustible materials near explosives can markedly increase gas pressures in enclosed structures; there is a lack of data on HE-combustible combinations; quasi-static loading calculations should include estimates of contributions from the burning of combustible materials whenevermore » such materials are expected to be in intimate contact with HE sources; and effects of combustibles should be investigated further to determine methods for prediction. Variations in charge to combustible mass, charge type, structure volume, degree of venting and degree of contact between HE and combustible sbould be studied.« less

Apollo 17 Lunar Surface Experiments package

NASA Image and Video Library

1972-05-10

S72-37260 (November 1972) --- The remote antenna for the Lunar Seismic Profiling Experiment, Numbered S-203, a component of the Apollo Lunar Surface Experiments Package which will be carried on the Apollo 17 lunar landing mission. LSPE components are four geophones similar to those used in earlier active seismic experiments an electronics package in the ALSEP central station, and eight explosive packages which will be deployed during the geology traverse. The four geophones will be placed one in the center and at each corner of a 90-meter equilateral triangle. Explosive charges placed on the surface will generate seismic waves of varying strengths to provide data on the structural profile of the landing site. After the charges have been fired by ground command, the experiment will settle down into a passive listening mode, detecting moonquakes, meteorite impacts and the thump caused by the Lunar Module ascent stage impact. The antenna is of the telescoping type.

Elaboration of the Charge Constructions of Explosives for the Structure of Facing Stone

NASA Astrophysics Data System (ADS)

Khomeriki, Sergo; Mataradze, Edgar; Chikhradze, Nikoloz; Losaberidze, Marine; Khomeriki, Davit; Shatberashvili, Grigol

2017-12-01

Increased demand for high-strength facing material caused the enhancement of the volume of explosives use in modern technologies of blocks production. The volume of broken rocks and crushing quality depends on the rock characteristics and on the properties of the explosive, in particular on its brisance and serviceability. Therefore, the correct selection of the explosive for the specific massif is of a considerable practical importance. For efficient mining of facing materials by explosion method the solving of such problems as determination of the method of blasthole drilling as well as of the regime and charge values, selection of the explosive, blastholes distribution in the face and their order is necessary. This paper focuses on technical solutions for conservation of rock natural structure in the blocks of facing material, mined by the use of the explosives. It has been established that the efficient solving of mentioned problem is attained by reducing of shock pulse duration. In such conditions the rigidity of crystalline lattice increases in high pressure area. As a result, the hazard if crack formation in structural unites and the increases of natural cracks are excluded. Short-time action of explosion pulse is possible only by linear charges of the explosives, characterized by high detonation velocity which detonate by the velocity of 7-7.5 km/sec and are characterized by very small critical diameter.

Optically-energized, emp-resistant, fast-acting, explosion initiating device

DOEpatents

Benson, David A.; Kuswa, Glenn W.

1987-01-01

Optical energy, provided from a remote user-operated source, is utilized to initially electrically charge a capacitor in a circuit that also contains an explosion initiating transducer in contact with a small explosive train contained in an attachable housing. Additional optical energy is subsequently supplied in a preferred embodiment to an optically responsive phototransistor acting in conjunction with a silicon controlled rectifer to release the stored electrical energy through the explosion initiating transducer to set off the explosive train. All energy transfers between the user and the explosive apparatus, either for charging it up or for setting it off, are conveyed optically and may be accomplished in a single optical fiber with coding to distinguish between specific optical energy transfers and between these and any extraneous signals.

Understanding ultrafine nanodiamond formation using nanostructured explosives

PubMed Central

Pichot, Vincent; Risse, Benedikt; Schnell, Fabien; Mory, Julien; Spitzer, Denis

2013-01-01

The detonation process is able to build new materials with a bottom-up approach. Diamond, the hardest material on earth, can be synthesized in this way. This unconventional synthesis route is possible due to the presence of carbon inside the high-explosive molecules: firing high-explosive mixtures with a negative oxygen balance in a non-oxidative environment leads to the formation of nanodiamond particles. Trinitrotoluene (TNT) and hexogen (RDX) are the explosives primarily used to synthesize nanodiamonds. Here we show that the use of nanostructured explosive charges leads to the formation of smaller detonation nanodiamonds, and it also provides new understanding of nanodiamond formation-mechanisms. The discontinuity of the explosive at the nanoscale level plays the key role in modifying the diamond particle size, and therefore varying the size with microstructured charges is impossible. PMID:23831716

Explosive nephrolithopaxy: reality or fiction?

PubMed

Miller, R A; Wickham, J E; Reynolds, S E; Westcott, A; Bailey, A

1984-05-01

The use of silver and lead azide explosive charges for the percutaneous distintegration of renal calculi has been investigated. Charges of 10 mg or more reliably reduced calculi to fragments of extractable size; however, the concomitant tissue effects would preclude the use of such charges clinically. Smaller charges require multiple applications. High-speed flash photography demonstrated the unfocussed nature of these discharges. Considerable improvements are anticipated when the shock waves are focused. The use of Nonel tubing is described, and future developments are discussed.

Lithium niobate explosion monitor

DOEpatents

Bundy, Charles H.; Graham, Robert A.; Kuehn, Stephen F.; Precit, Richard R.; Rogers, Michael S.

1990-01-01

Monitoring explosive devices is accomplished with a substantially z-cut lithium niobate crystal in abutment with the explosive device. Upon impact by a shock wave from detonation of the explosive device, the crystal emits a current pulse prior to destruction of the crystal. The current pulse is detected by a current viewing transformer and recorded as a function of time in nanoseconds. In order to self-check the crystal, the crystal has a chromium film resistor deposited thereon which may be heated by a current pulse prior to detonation. This generates a charge which is detected by a charge amplifier.

Lithium niobate explosion monitor

DOEpatents

Bundy, C.H.; Graham, R.A.; Kuehn, S.F.; Precit, R.R.; Rogers, M.S.

1990-01-09

Monitoring explosive devices is accomplished with a substantially z-cut lithium niobate crystal in abutment with the explosive device. Upon impact by a shock wave from detonation of the explosive device, the crystal emits a current pulse prior to destruction of the crystal. The current pulse is detected by a current viewing transformer and recorded as a function of time in nanoseconds. In order to self-check the crystal, the crystal has a chromium film resistor deposited thereon which may be heated by a current pulse prior to detonation. This generates a charge which is detected by a charge amplifier. 8 figs.

On the Violence of High Explosive Reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarver, C M; Chidester, S K

High explosive reactions can be caused by three general energy deposition processes: impact ignition by frictional and/or shear heating; bulk thermal heating; and shock compression. The violence of the subsequent reaction varies from benign slow combustion to catastrophic detonation of the entire charge. The degree of violence depends on many variables, including the rate of energy delivery, the physical and chemical properties of the explosive, and the strength of the confinement surrounding the explosive charge. The current state of experimental and computer modeling research on the violence of impact, thermal, and shock-induced reactions is reviewed.

Numberical simulation of the effects of radially injected barium plasma in the ionosphere

NASA Technical Reports Server (NTRS)

Swift, D. W.

1985-01-01

The morphology of the ion cloud in the radial shaped charge barium injection was studied. The shape of the ion cloud that remains after the explosive products and neutral barium clears away was examined. The ion cloud which has the configuration of a rimless wagon wheel is shown. The major features are the 2.5 km radius black hole in the center of the cloud, the surrounding ring of barium ion and the spokes of barium ionization radiating away from the center. The cloud shows no evolution after it emerges from the neutral debris and it is concluded that it is formed within 5 seconds of the event. A numerical model is used to calculate the motion of ions and electrons subject to the electrostatic and lorenz forces.

A critical velocity interaction between fast barium and strontium atoms and the terrestial ionospheric plasma

NASA Technical Reports Server (NTRS)

Deehr, C. S.; Wescott, E. M.; Stenbaek-Nielsen, H.; Romick, G. J.; Hallinan, T. J.; Foeppl, H.

1982-01-01

A disk of barium and strontium vapor traveling radially outward, perpendicular to the geomagnetic field lines, may be created by the detonation of a high-explosive, radially shaped charge with a liner composed of the two metals in the upper atmosphere. Because of solar radiation resonance, both the barium and the strontium may be optically tracked. Observations indicate the early formation of the metal ions thus evolved into a disk-shaped, stellate structure with a dark hole at the center of a radial structure. The results of these experiments indicate that the process could occur on a cosmic scale, and that unconfirmed aspects of the theory relating to this process could be determined through variation of the parameters in future radial rocket experiments.

PHOTONICS AND NANOTECHNOLOGY Laser-induced modification of transparent crystals and glasses

NASA Astrophysics Data System (ADS)

Bulgakova, N. M.; Stoian, Razvan; Rosenfeld, A.

2010-12-01

We analyse the processes taking place in transparent crystals and glasses irradiated by ultrashort laser pulses in the regimes typical of various applications in optoelectronics and photonics. We consider some phenomena, which have been previously described by the authors within the different model representations: charging of the dielectric surface due to electron photoemission resulting in a Coulomb explosion; crater shaping by using an adaptive control of the laser pulse shape; optimisation of the waveguide writing in materials strongly resistant to laser-induced compaction under ordinary irradiation conditions. The developed models and analysis of the processes relying on these models include the elements of the solid-state physics, plasma physics, thermodynamics, theory of elasticity and plasticity. Some important experimental observations which require explanations and adequate description are summarised.

Close-in Blast Waves from Spherical Charges*

NASA Astrophysics Data System (ADS)

Howard, William; Kuhl, Allen

2011-06-01

We study the close-in blast waves created by the detonation of spherical high explosives (HE) charges, via numerical simulations with our Arbitrary-Lagrange-Eulerian (ALE3D) code. We used a finely-resolved, fixed Eulerian 2-D mesh (200 μm per cell) to capture the detonation of the charge, the blast wave propagation in air, and the reflection of the blast wave from an ideal surface. The thermodynamic properties of the detonation products and air were specified by the Cheetah code. A programmed-burn model was used to detonate the charge at a rate based on measured detonation velocities. The results were analyzed to evaluate the: (i) free air pressure-range curves: Δps (R) , (ii) free air impulse curves, (iii) reflected pressure-range curves, and (iv) reflected impulse-range curves. A variety of explosives were studied. Conclusions are: (i) close-in (R < 10 cm /g 1 / 3) , each explosive had its own (unique) blast wave (e.g., Δps (R , HE) ~ a /Rn , where n is different for each explosive); (ii) these close-in blast waves do not scale with the ``Heat of Detonation'' of the explosive (because close-in, there is not enough time to fully couple the chemical energy to the air via piston work); (iii) instead they are related to the detonation conditions inside the charge. Scaling laws will be proposed for such close-in blast waves.

Process of breaking and rendering permeable a subterranean rock mass

DOEpatents

Lekas, Mitchell A.

1980-01-01

The process of the present invention involves the following steps: producing, as by hydrofracing, a substantially horizontal fracture in the subterranean rock mass to be processed; emplacing an explosive charge in the mass in spaced juxtaposed position to the fracture; enlarging the fracture to create a void space thereat, an initial lifting of the overburden, and to provide a free face juxtaposed to and arranged to cooperate with the emplaced explosive charge; and exploding the charge against the free face for fragmenting the rock and to distribute the space, thus providing fractured, pervious, rubble-ized rock in an enclosed subterranean chamber. Firing of the charge provides a further lifting of the overburden, an enlargement of the chamber and a larger void space to distribute throughout the rubble-ized rock within the chamber. In some forms of the invention an explosive charge is used to produce a transitory enlargement of the fracture, and the juxtaposed emplaced charge is fired during the critical period of enlargement of the fracture.

Inductive Measurement of Plasma Jet Electrical Conductivity (MSFC Center Director's discretionary Fund). Part 2

NASA Technical Reports Server (NTRS)

Turner, M. W.; Hawk, C. W.; Litchford, R. J.

2001-01-01

Measurement of plasma jet electrical conductivity has utility in the development of explosively driven magnetohydrodynamic (MHD) energy converters as well as magnetic flux compression reaction chambers for nuclear/chemical pulse propulsion and power. Within these types of reactors, the physical parameter of critical importance to underlying MHD processes is the magnetic Reynolds number, the value of which depends upon the product of plasma electrical conductivity and velocity. Therefore, a thorough understanding of MHD phenomena at high magnetic Reynolds number is essential, and methods are needed for the accurate and reliable measurement of electrical conductivity in high-speed plasma jets. It is well known that direct measurements using electrodes suffer from large surface resistance, and an electrodeless technique is desired. To address this need, an inductive probing scheme, originally developed for shock tube studies, has been adapted. In this method, the perturbation of an applied magnetic field by a plasma jet induces a voltage in a search coil, which, in turn, can be used to infer electrical conductivity through the inversion of a Fredholm integral equation of the first kind. A 1-in.-diameter probe using a light-gas gun. Exploratory laboratory experiments were carried out using plasma jets expelled from 15-g shaped charges. Measured conductivities were in the range of 4 kS/m for unseeded octol charges and 26 kS/m for seeded octol charges containing 2-percent potassium carbonate by mass.

Laser-based standoff detection of explosives: a critical review.

PubMed

Wallin, Sara; Pettersson, Anna; Ostmark, Henric; Hobro, Alison

2009-09-01

A review of standoff detection technologies for explosives has been made. The review is focused on trace detection methods (methods aiming to detect traces from handling explosives or the vapours surrounding an explosive charge due to the vapour pressure of the explosive) rather than bulk detection methods (methods aiming to detect the bulk explosive charge). The requirements for standoff detection technologies are discussed. The technologies discussed are mostly laser-based trace detection technologies, such as laser-induced-breakdown spectroscopy, Raman spectroscopy, laser-induced-fluorescence spectroscopy and IR spectroscopy but the bulk detection technologies millimetre wave imaging and terahertz spectroscopy are also discussed as a complement to the laser-based methods. The review includes novel techniques, not yet tested in realistic environments, more mature technologies which have been tested outdoors in realistic environments as well as the most mature millimetre wave imaging technique.

Rapid and slow: Varying magma ascent rates as a mechanism for Vulcanian explosions

NASA Astrophysics Data System (ADS)

Cassidy, Mike; Cole, Paul. D.; Hicks, Kelby E.; Varley, Nick R.; Peters, Nial; Lerner, Allan H.

2015-06-01

Vulcanian explosions are one of the most common types of volcanic activity observed at silicic volcanoes. Magma ascent rates are often invoked as being the fundamental control on their explosivity, yet this factor is poorly constrained for low magnitude end-member Vulcanian explosions, which are particularly poorly understood, partly due to the rarity of ash samples and low gas fluxes. We describe ash generated by small Vulcanian explosions at Volcán de Colima in 2013, where we document for the first time marked differences in the vesicularity, crystal characteristics (volume fraction, size and shape) and glass compositions in juvenile material from discrete events. We interpret these variations as representing differing ascent styles and speeds of magma pulses within the conduit. Heterogeneous degassing during ascent leads to fast ascending, gas-rich magma pulses together with slow ascending gas-poor magma pulses within the same conduit. This inferred heterogeneity is complemented by SO2 flux data, which show transient episodes of both open and closed system degassing, indicating efficient shallow fracture sealing mechanisms, which allows for gas overpressure to generate small Vulcanian explosions.

Dual mode warhead

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obrsky, J.; Alexander, A.A.; Griffen, O.H.

1980-12-31

A dual mode warhead is provided for use against both soft and hard targets and capable of sensing which type of target has been struck comprising a casing made of a ductile material containing an explosive charge and a fuze assembly. The ductile warhead casing will mushroom and later split upon striking a hard target while still confining the explosive. Proper ductility and confinement are necessary for fuze sensing. The fuze assembly contains a pair of parallel firing trains, one initiated only by high and one by low impact deceleration. The firing train actuated by low impact deceleration contains amore » pyrotechnic delay to allow penetration of soft targets.« less

Analysis of the Explosive Internal Impact on the Barriers of Building Structures

NASA Astrophysics Data System (ADS)

Siwiński, Jarosław; Stolarski, Adam

2017-10-01

Work issues concern the safety of construction in relation to the hazards arising from explosion of the explosive charge located inside the building. The algorithms proposed in the paper for determining the parameters of the overpressure wave resulting from the detonation of clustered explosive charges, determine the basis for numerical simulation analyzes. Determination of the maximum value of peak pressure on the wave forehead of an internal explosion is presented on the basis of reflected wave analysis. Changeability in time of the internal explosion action describes the overpressure phase only. The analysis of the load caused by the internal explosive charge detonation was carried out under conditions of the undisturbed standard atmosphere. A load determination algorithm has been developed, taking into account the geometrical characteristics of the building barriers and the rooms as well as the parameters of environment in which the detonation occurs. The way of taking into account the influence of venting surfaces, i.e. windows, doors, ventilation ducts, on the overpressure wave parameters, was presented. Discloses a method to take into account the effect of the surface relief, i.e. windows, doors, air ducts, pressure wave parameters. Modification of the method for explosive overpressure determination presented by Cormie, Smith, Mays (2009), was proposed in the paper. This modification was developed on the basis of substitute impulse analysis for multiple overpressure pulses. In order to take into account the pressure distribution of explosive gases on the barrier surface, the method of modification the relationship for determination the changeability over time and space of the pressure of explosive gases, was presented. For this purpose, the changeability of the pressure wave angles of incidence to the barrier and the distance of the explosive charge to any point on the surface of the barrier, was taken into account. Based on the developed procedure, the overpressure changeability over time was determined for selected measurement points of the reference room. A comparative analysis of the determined loadings with experimental results and theoretical results of other authors, taken from the original work of Weerhiejm et al. (2012), was carried out.

A Coulomb explosion strategy to tailor the nano-architecture of α-MoO3 nanobelts and an insight into its intrinsic mechanism.

PubMed

Zhang, Junli; Zhu, Liu; Yang, Yu; Yong, Huadong; Zhang, Junwei; Peng, Yong; Fu, Jiecai

2018-05-03

Tailoring the nanoarchitecture of materials is significant for the development of nanoscience and nanotechnology. To date, one of the most powerful strategies is convergent electron beam irradiation (EBI). However, only two main functions of knock-on or atomic displacement have been achieved to date. In this study, a Coulomb explosion phenomenon was found to occur in α-MoO3 nanobelts (NBs) under electron beam irradiation, which was controllable and could be used to efficiently create nanostructures such as holes, gaps, and other atomic/nanometer patterns on a single α-MoO3 NB. Theoretical simulations starting from the charging state, charging rate to the threshold time of Coulomb explosion reveal that the Coulomb explosion phenomenon should result from positive charging. The results also show that the multiple charged regions are quickly fragmented, and the monolayered α-MoO3 pieces can then be peeled off once the Coulombic repulsion is sufficient to break the Mo-O bonds in the crystalline structure. It is believed that this efficient and versatile strategy may open up a new avenue to tailor α-MoO3 NBs or other kind of transition metal dichalcogenides via the Coulomb explosion effect.

Extremely late photometry of the nearby SN 2011fe

NASA Astrophysics Data System (ADS)

Kerzendorf, W. E.; McCully, C.; Taubenberger, S.; Jerkstrand, A.; Seitenzahl, I.; Ruiter, A. J.; Spyromilio, J.; Long, K. S.; Fransson, C.

2017-12-01

Type Ia supernovae are widely accepted to be the outcomes of thermonuclear explosions in white dwarf stars. However, many details of these explosions remain uncertain (e.g. the mass, ignition mechanism and flame speed). Theory predicts that at very late times (beyond 1000 d) it might be possible to distinguish between explosion models. Few very nearby supernovae can be observed that long after the explosion. The Type Ia supernova SN 2011fe located in M101 and along a line of sight with negligible extinction, provides us with the once-in-a-lifetime chance to obtain measurements that may distinguish between theoretical models. In this work, we present the analysis of photometric data of SN 2011fe taken between 900 and 1600 d after explosion with Gemini and HST. At these extremely late epochs theory suggests that the light-curve shape might be used to measure isotopic abundances which is a useful model discriminant. However, we show in this work that there are several currently not well constrained physical processes introducing large systematic uncertainties to the isotopic abundance measurement. We conclude that without further detailed knowledge of the physical processes at this late stage one cannot reliably exclude any models on the basis of this data set.

Using Neutron Diffraction to Investigate Texture Evolution During Consolidation of Deuterated Triaminotrinitrobenzene (d-TATB) Explosive Powder

DOE PAGES

Luscher, Darby J.; Yeager, John D.; Clausen, Bjørn; ...

2017-05-14

Triaminotrinitrobenzene (TATB) is a highly anisotropic molecular crystal used in several plastic-bonded explosive (PBX) formulations. A complete understanding of the orientation distribution of TATB particles throughout a PBX charge is required to understand spatially variable, anisotropic macroscale properties of the charge. Although texture of these materials can be measured after they have been subjected to mechanical or thermal loads, measuring texture evolution in situ is important in order to identify mechanisms of crystal deformation and reorientation used to better inform thermomechanical models. Neutron diffraction measurements were used to estimate crystallographic reorientation while deuterated TATB (d-TATB) powder was consolidated into amore » cylindrical pellet via a uniaxial die-pressing operation at room temperature. Both the final texture of the pressed pellet and the in situ evolution of texture during pressing were measured, showing that the d-TATB grains reorient such that (001) poles become preferentially aligned with the pressing direction. A compaction model is used to predict the evolution of texture in the pellet during the pressing process, finding that the original model overpredicted the texture strength compared to these measurements. The theory was extended to account for initial particle shape and pore space, bringing the results into good agreement with the data.« less

Using Neutron Diffraction to Investigate Texture Evolution During Consolidation of Deuterated Triaminotrinitrobenzene (d-TATB) Explosive Powder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luscher, Darby J.; Yeager, John D.; Clausen, Bjørn

Triaminotrinitrobenzene (TATB) is a highly anisotropic molecular crystal used in several plastic-bonded explosive (PBX) formulations. A complete understanding of the orientation distribution of TATB particles throughout a PBX charge is required to understand spatially variable, anisotropic macroscale properties of the charge. Although texture of these materials can be measured after they have been subjected to mechanical or thermal loads, measuring texture evolution in situ is important in order to identify mechanisms of crystal deformation and reorientation used to better inform thermomechanical models. Neutron diffraction measurements were used to estimate crystallographic reorientation while deuterated TATB (d-TATB) powder was consolidated into amore » cylindrical pellet via a uniaxial die-pressing operation at room temperature. Both the final texture of the pressed pellet and the in situ evolution of texture during pressing were measured, showing that the d-TATB grains reorient such that (001) poles become preferentially aligned with the pressing direction. A compaction model is used to predict the evolution of texture in the pellet during the pressing process, finding that the original model overpredicted the texture strength compared to these measurements. The theory was extended to account for initial particle shape and pore space, bringing the results into good agreement with the data.« less

Detonation Velocity-Diameter Relation in Gelled Explosive with Inert Inclusions

NASA Astrophysics Data System (ADS)

Higgins, Andrew; Loiseau, Jason; Mi, Xiaocheng

2017-06-01

The detonation velocity is measured in a gelled explosive that has been sensitized via the addition of glass microballoons (GMBs) and additionally diluted via the inclusion of large scale (300-700 micron) inert inclusions. The base explosive is nitromethane that has been gelled via the addition of poly(methyl methacrylate) and then sensitized via hot-spot inducing glass microballoons. Inert inclusions (e.g., glass, steel beads) are then added to the explosive to make a heterogeneous explosive with heterogeneities that are at a scale disparate from those of the microballoons. This system has the potential to be a synthetic explosive that can be tuned to have the properties of more complex commercial blasting agents. The velocity-diameter relation is studied using weak confinement (polyvinyl chloride) and time-of-arrival gages. The results are also used to further explore the phenomenon of anomalous scaling between axisymmetric charges (cylinders) and two-dimensional (slab) charges.

One-Dimensional Thermal Violence Cook-Off Test

NASA Astrophysics Data System (ADS)

Cook, Malcolm; Stennett, Christopher; University of Cranfield, Shrivenham, Swindon, SN6 8LA Team; AWE plc, Aldermaston, Reading Bershire, RG7 4PR, UK Team

2017-06-01

The One-Dimensional Thermal Violence (ODTV) test is designed to quantify and rank the violence of HE charges when heated to elevated temperatures. The test design consists of a central spherical explosive pellet encased in two aluminium barrel shaped halves, fitted with a copper sealing ring, encased by two aluminium locking rings placed over them from either end. The outer surface of the capsule is heated uniformly by placing in a pre-heated molten solder bath. This allows the time-to-explosion to be recorded for different initial bath temperatures. The ODTV capsule can hold samples up to 30mm in diameter. Diagnostics include both thermocouples and Photon Dopler Velocimetry (PDV). A series of live firings have been carried out on a range of bespoke HMX/HTPB explosives. These include HMX/HTPB mix ratios of 95/5, 92/8, 90/10, 88/12 and 85/15. These tests showed that the ODTV capsule had sufficient confinement and size that it could capture the spectrum of events expected from these formulations. It has been demonstrated that the deformation of the heater cup (that houses the molten solder) can be used as an additional violence metric along with the fragmentation and PDV wall velocities of the aluminium ODTV capsule.

Hypervelocity gun. [using both electric and chemical energy for projectile propulsion

NASA Technical Reports Server (NTRS)

Ford, F. C.; Biehl, A. J. (Inventor)

1965-01-01

A velocity amplifier system which uses both electric and chemical energy for projectile propulsion is provided in a compact hypervelocity gun suitable for laboratory use. A relatively heavy layer of a tamping material such as concrete encloses a loop of an electrically conductive material. An explosive charge at least partially surrounding the loop is adapted to collapse the loop upon detonation of the charge. A source of electricity charges the loop through two leads, and an electric switch which is activated by the charge explosive charge, disconnects the leads from the source of electricity and short circuits them. An opening in the tamping material extends to the loop and forms a barrel. The loop, necked down in the opening, forms the sabot on which the projectile is located. When the loop is electrically charged and the explosive detonated, the loop is short circuited and collapsed thus building up a magnetic field which acts as a sabot catcher. The sabot is detached from the loop and the sabot and projectile are accelerated to hypervelocity.

Study on the Structures of Two Booster Pellets Having High Initiation Capacity

NASA Astrophysics Data System (ADS)

Shuang-Qi, Hu; Hong-Rong, Liu; Li-shuang, Hu; Xiong, Cao; Xiang-Chao, Mi; Hai-Xia, Zhao

2014-05-01

Insensitive munitions (IM) improve the survivability of both weapons and their associated platforms, which can lead to a reduction in casualties, mission losses, and whole life costs. All weapon systems contain an explosive train that needs to meet IM criteria but reliably initiate a main charge explosive. To ensure that these diametrically opposed requirements can be achieved, new highly effective booster charge structures were designed. The initiation capacity of the two booster pellets was studied using varied composition and axial-steel-dent methods. The results showed that the two new booster pellets can initiate standard main charge pellets with less explosive mass than the ordinary cylindrical booster pellet. The numerical simulation results were in good agreement with the experiment results.

Historical Survey: German Research on Hydrogen Peroxide/Alcohol Explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parmeter, John E.

Discussion of HP/fuel explosives in the scientific literature dates back to at least 1927. A paper was published that year in a German journal entitled On Hydrogen Peroxide Explosives [Bamberger and Nussbaum 1927]. The paper dealt with HP/cotton/Vaseline formulations, specifically HP89/cotton/Vaseline (76/15/9) and (70/8.5/12.5). The authors performed experiments with charge masses of 250-750 g and charge diameters of 35-45 mm. This short paper provides brief discussion on the observed qualitative effects of detonations but does not report detonation velocities.

Safety and performance enhancement circuit for primary explosive detonators

DOEpatents

Davis, Ronald W [Tracy, CA

2006-04-04

A safety and performance enhancement arrangement for primary explosive detonators. This arrangement involves a circuit containing an energy storage capacitor and preset self-trigger to protect the primary explosive detonator from electrostatic discharge (ESD). The circuit does not discharge into the detonator until a sufficient level of charge is acquired on the capacitor. The circuit parameters are designed so that normal ESD environments cannot charge the protection circuit to a level to achieve discharge. When functioned, the performance of the detonator is also improved because of the close coupling of the stored energy.

Detonation shock dynamics with an acceleration relation for nitromethane and TATB

NASA Astrophysics Data System (ADS)

Swift, Damian; Kraus, Richard; Mulford, Roberta; White, Stephen

2015-06-01

The propagation of curved detonation waves has been treated phenomenologically through models of the speed D of a detonation wave as a function of its curvature K, in the Whitham-Bdzil-Lambourn model, also known as detonation shock dynamics. D(K) relations, and the edge angle with adjacent material, have been deduced from the steady shape of detonation waves in long rods and slabs of explosive. Nonlinear D(K) relations have proven necessary to interpret data from charges of different diameter, and even then the D(K) relation may not transfer between diameters. This is an indication that the D(K) relation oversimplifies the kinematics. It is also possible to interpret wave-shape data in terms of an acceleration relation, as used in Brun's Jouguet relaxe model. One form of acceleration behavior is to couple an asymptotic D(K) relation with a time-dependent relaxation toward it from the instantaneous, local speed. This approach is also capable of modeling overdriving of a detonation by a booster. Using archival data for the TATB-based explosive EDC35 and for nitromethane, we found that a simple linear asymptotic D(K) relation with a constant relaxation rate was able to reproduce the experimental wave-shapes better, with fewer parameters, than a nonlinear instantaneous D(K) relation. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Cell phone explosion.

PubMed

Atreya, Alok; Kanchan, Tanuj; Nepal, Samata; Pandey, Bhuwan Raj

2016-03-01

Cell phone explosions and resultant burn injuries are rarely reported in the scientific literature. We report a case of cell phone explosion that occurred when a young male was listening to music while the mobile was plugged in for charging. © The Author(s) 2015.

Closed-form model for the analysis of W-type shaped charges

NASA Astrophysics Data System (ADS)

Mahdian, A.; Ghayour, M.; Liaghat, G. H.

2013-09-01

This paper presents a closed-form model for the analysis of symmetric planar W-type shaped charges (WSCs) with two V-sections, which produce two primary cores and two primary jets. If these two V-sections have proper asymmetry, these primary cores will force two primary jets into a secondary core formed on the axis of symmetry of a planar symmetric WSC. For the analysis of such a planar WSC, a complete generalized model for an asymmetric planar V-shaped charge (VSC) with any desired order of asymmetry is mandatory. In this paper, the model is applied to describe the secondary jet formation in the WSC. By presenting a closed-form analysis of the WSC, the secondary jet specifications can be easily evaluated and, thus, can be compared with respect to the jet quantities in symmetric or asymmetric VSCs. Finally, for the primary and secondary jets, the coherency conditions are investigated, and the critical parameters responsible for these conditions are determined.

Shock sensing dual mode warhead

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamblen, M.; Walchak, M.T.; Richmond, L.

1980-12-31

A shock sensing dual mode warhead is provided for use against both soft and hard targets and is capable of sensing which type of target has been struck. The warhead comprises a casing made of a ductile material containing an explosive charge and a fuze assembly. The ductile warhead casing will mushroom upon striking a hard target while still confining the explosive. Proper ductility and confinement are necessary for fuze shock sensing. The fuze assembly contains a pair of parallel firing trains, one initiated only by dynamic pressure caused high impact deceleration and one initiated by low impact deceleration. Themore » firing train actuated by high impact deceleration senses dynamic pressure transmitted, during deformation of the warhead, through the explosive filler which is employed as a fuzing signature. The firing train actuated by low impact deceleration contains a pyrotechnic delay to allow penetration of soft targets.« less

27 CFR 555.142 - Relief from disabilities (effective January 24, 2003).

Code of Federal Regulations, 2014 CFR

2014-04-01

... Discharge from Active Duty (Department of Defense Form 214), Charge Sheet (Department of Defense Form 458... ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE EXPLOSIVES COMMERCE IN EXPLOSIVES... records, statements and other information concerning employment, medical history, military service...

High-explosive driven crowbar switch

DOEpatents

Dike, Robert S.; Kewish, Jr., Ralph W.

1976-01-13

The disclosure relates to a compact explosive driven switch for use as a low resistance, low inductance crowbar switch. A high-explosive charge extrudes a deformable conductive metallic plate through a polyethylene insulating layer to achieve a hard current contact with a supportive annular conductor.

NASA missions studies magnetic space explosions

NASA Image and Video Library

2017-12-08

Every day, invisible magnetic explosions are happening around Earth, on the surface of the sun and across the universe. These explosions, known as magnetic reconnection, occur when magnetic field lines cross, releasing stored magnetic energy. Such explosions are a key way that clouds of charged particles — plasmas — are accelerated throughout the universe. In Earth’s magnetosphere — the giant magnetic bubble surrounding our planet — these magnetic reconnections can fling charged particles toward Earth, triggering auroras. Read more: go.nasa.gov/2mnMtDm Video caption - In this simulation, a reconnection even pushes a blob of plasma toward Earth. The jet blown in the opposite direction wobbles due to the unstable conditions. Credit: NASA’s Goddard Space Flight Center/Yi-Hsin Liu/Joy Ng, producer

The safety and reliability of the S and A mechanism designed for the NASA/LSPE program

NASA Technical Reports Server (NTRS)

Montesi, L. J.

1973-01-01

Under contract to the Manned Spacecraft Center, NASA/Houston, NOL developed a number of explosive charges for use in studying the surface of the moon during Apollo 17 activities. The charges were part of the Lunar Seismic Profiling Experiment (LSPE). When the Safety and Arming Device used in the previous ALSEP experiments was found unsuitable for use with the new explosive packages, NOL also designed the Safety and Arming Mechanism, and the safety and reliability tests conducted are described. The results of the test program indicate that the detonation transfer probability between the armed explosive components exceeds 0.9999, and is less than 0.0001 when the explosive components are in the safe position.

Decomposition of the Seismic Source Using Numerical Simulations and Observations of Nuclear Explosions

DTIC Science & Technology

2017-05-31

SUBJECT TERMS nonlinear finite element calculations, nuclear explosion monitoring, topography 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18...3D North Korea calculations........ Figure 6. The CRAM 3D finite element outer grid (left) is rectangular......................... Figure 7. Stress...Figure 6. The CRAM 3D finite element outer grid (left) is rectangular. The inner grid (center) is shaped to match the shape of the explosion shock wave

Energetic Residues and Crater Geometries from the Firing of 120-mm High-Explosive Mortar Projectiles into Eagle River Flats, June 2007

DTIC Science & Technology

2008-07-01

samples. ERDC/CRREL TR-08-10 15 c. US DH-48 isokinetic sampler. Figure 7 (cont’d). The second activity was the collection of soil at the...3 0.28 Mc1/3 0.3 Mc1/3 Ra Apparent radius of the crater in meters Mc Mass of the explosive charge in kilograms Da Apparent depth of the crater in... meters The apparent depth and radius of a crater will increase with the depth of explosive charge below the surface down to a maximum depth called

Rigid polyurethane foam as an efficient material for shock wave attenuation

NASA Astrophysics Data System (ADS)

Komissarov, P. V.; Borisov, A. A.; Sokolov, G. N.; Lavrov, V. V.

2016-09-01

A new method for reducing parameters of blast waves generated by explosions of HE charges on ground is presented. Most of the traditional techniques reduce the wave parameters at a certain distance from the charge, i.e. as a matter of fact the damping device interacts with a completely formed shock wave. The proposed approach is to use rigid polyurethane foam coating immediately the explosive charge. A distributed structure of such a foam block that provides most efficient shock wave attenuation is suggested. Results of experimental shock wave investigations recorded in tests in which HE charges have been exploded with damping devices and without it are compared.

Furthering the investigation of eruption styles through quantitative shape analyses of volcanic ash particles

NASA Astrophysics Data System (ADS)

Nurfiani, D.; Bouvet de Maisonneuve, C.

2018-04-01

Volcanic ash morphology has been quantitatively investigated for various aims such as studying the settling velocity of ash for modelling purposes and understanding the fragmentation processes at the origin of explosive eruptions. In an attempt to investigate the usefulness of ash morphometry for monitoring purposes, we analyzed the shape of volcanic ash particles through a combination of (1) traditional shape descriptors such as solidity, convexity, axial ratio and form factor and (2) fractal analysis using the Euclidean Distance transform (EDT) method. We compare ash samples from the hydrothermal eruptions of Iwodake (Japan) in 2013, Tangkuban Perahu (Indonesia) in 2013 and Marapi (Sumatra, Indonesia) in 2015, the dome explosions of Merapi (Java, Indonesia) in 2013, the Vulcanian eruptions of Merapi in 2010 and Tavurvur (Rabaul, Papaua New Guinea) in 2014, and the Plinian eruption of Kelud (Indonesia) in 2014. Particle size and shape measurements were acquired from a Particle Size Analyzer with a microscope camera attached to the instrument. Clear differences between dense/blocky particles from hydrothermal or dome explosions and vesicular particles produced by the fragmentation of gas-bearing molten magma are well highlighted by conventional shape descriptors and the fractal method. In addition, subtle differences between dense/blocky particles produced by hydrothermal explosions, dome explosions, or quench granulation during phreatomagmatic eruptions can be evidenced with the fractal method. The combination of shape descriptors and fractal analysis is therefore potentially able to distinguish between juvenile and non-juvenile magma, which is of importance for eruption monitoring.

Explosive Joining for Nuclear-Reactor Repair

NASA Technical Reports Server (NTRS)

Bement, L. J.; Bailey, J. W.

1983-01-01

In explosive joining technique, adapter flange from fuel channel machined to incorporate a V-notch interface. Ribbon explosive, 1/2 inch (1.3 cm) in width, drives V-notched wall of adapter into bellows assembly, producing atomic-level metallurgical bond. Ribbon charge yields joint with double parent metal strength.

HIGH EXPLOSIVE CRATER STUDIES: TUFF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphey, B.F.

1961-04-01

Spherical charges of TNT, each weighing 256 pounds, were exploded at various depths in tuff to determine apparent crater dimensions in a soft rock. No craters were obtained for depths of burst equal to or greater than 13.3 feet. It was deduced that rock fragments were sufficiently large that charges of greater magnitude should be employed for crater experiments intended as models of nuclear explosions. (auth)

Explosive magnetic reconnection caused by an X-shaped current-vortex layer in a collisionless plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirota, M.; Hattori, Y.; Morrison, P. J.

2015-05-15

A mechanism for explosive magnetic reconnection is investigated by analyzing the nonlinear evolution of a collisionless tearing mode in a two-fluid model that includes the effects of electron inertia and temperature. These effects cooperatively enable a fast reconnection by forming an X-shaped current-vortex layer centered at the reconnection point. A high-resolution simulation of this model for an unprecedentedly small electron skin depth d{sub e} and ion-sound gyroradius ρ{sub s}, satisfying d{sub e}=ρ{sub s}, shows an explosive tendency for nonlinear growth of the tearing mode, where it is newly found that the explosive widening of the X-shaped layer occurs locally aroundmore » the reconnection point with the length of the X shape being shorter than the domain length and the wavelength of the linear tearing mode. The reason for the onset of this locally enhanced reconnection is explained theoretically by developing a novel nonlinear and nonequilibrium inner solution that models the local X-shaped layer, and then matching it to an outer solution that is approximated by a linear tearing eigenmode with a shorter wavelength than the domain length. This theoretical model proves that the local reconnection can release the magnetic energy more efficiently than the global one and the estimated scaling of the explosive growth rate agrees well with the simulation results.« less

30 CFR 77.1910 - Explosives and blasting; general.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and blasting; general. 77.1910... COAL MINES Slope and Shaft Sinking § 77.1910 Explosives and blasting; general. (a) Light and power circuits shall be disconnected or removed from the blasting area before charging and blasting. (b) All...

Plasma Discharge Initiation of Explosives in Rock Blasting Application: A Case Study

NASA Astrophysics Data System (ADS)

Jae-Ou, Chae; Young-Jun, Jeong; V, M. Shmelev; A, A. Denicaev; V, M. Poutchkov; V, Ravi

2006-07-01

A plasma discharge initiation system for the explosive volumetric combustion charge was designed, investigated and developed for practical application. Laboratory scale experiments were carried out before conducting the large scale field tests. The resultant explosions gave rise to less noise, insignificant seismic vibrations and good specific explosive consumption for rock blasting. Importantly, the technique was found to be safe and environmentally friendly.

Pulsating aurora induced by upper atmospheric barium releases

NASA Technical Reports Server (NTRS)

Deehr, C.; Romick, G.

1977-01-01

The paper reports the apparent generation of pulsating aurora by explosive releases of barium vapor near 250 km altitude. This effect occurred only when the explosions were in the path of precipitating electrons associated with the visible aurora. Each explosive charge was a standard 1.5 kg thermite mixture of Ba and CuO with an excess of Ba metal which was vaporized and dispersed by the thermite explosion. Traces of Sr, Na, and Li were added to some of the charges, and monitoring was achieved by ground-based spectrophotometric observations. On March 28, 1976, an increase in emission at 5577 A and at 4278 A was observed in association with the first two bursts, these emissions pulsating with roughly a 10 sec period for approximately 60 to 100 sec after the burst.

Numerical simulations of microcrack-related damage and ignition behavior of mild-impacted polymer bonded explosives.

PubMed

Yang, Kun; Wu, Yanqing; Huang, Fenglei

2018-08-15

A physical model is developed to describe the viscoelastic-plastic deformation, cracking damage, and ignition behavior of polymer-bonded explosives (PBXs) under mild impact. This model improves on the viscoelastic-statistical crack mechanical model (Visco-SCRAM) in several respects. (i) The proposed model introduces rate-dependent plasticity into the framework which is more suitable for explosives with relatively high binder content. (ii) Damage evolution is calculated by the generalized Griffith instability criterion with the dominant (most unstable) crack size rather than the averaged crack size over all crack orientations. (iii) The fast burning of cracks following ignition and the effects of gaseous products on crack opening are considered. The predicted uniaxial and triaxial stress-strain responses of PBX9501 sample under dynamic compression loading are presented to illustrate the main features of the materials. For an uncovered cylindrical PBX charge impacted by a flat-nosed rod, the simulated results show that a triangular-shaped dead zone is formed beneath the front of the rod. The cracks in the dead zone are stable due to friction-locked stress state, whereas the cracks near the front edges of dead zone become unstable and turn into hotspots due to high-shear effects. Copyright © 2018 Elsevier B.V. All rights reserved.

On the neutralization of bacterial spores in post-detonation flows

NASA Astrophysics Data System (ADS)

Gottiparthi, K. C.; Schulz, J. C.; Menon, S.

2014-09-01

In multiple operational scenarios, explosive charges are used to neutralize confined or unconfined stores of bacterial spores. The spore destruction is achieved by post-detonation combustion and mixing of hot detonation product gases with the ambient flow and spore clouds. In this work, blast wave interaction with bacterial spore clouds and the effect of post-detonation combustion on spore neutralization are investigated using numerical simulations. Spherical explosive charges (radius, = 5.9 cm) comprising of nitromethane are modeled in the vicinity of a spore cloud, and the spore kill in the post-detonation flow is quantified. The effect of the mass of the spores and the initial distance, , of the spore cloud from the explosive charge on the percentage of spores neutralized is investigated. When the spores are initially placed within a distance of 3.0, within 0.1 ms after detonation of the charge, all the spores are neutralized by the blast wave and the hot detonation product gases. In contrast, almost all the spores survived the explosion when is greater than 8.0. The percentage of intact spores varied from 0 to 100 for 3.0 8.0 with spore neutralization dependent on time spent by the spores in the post-detonation mixing/combustion zone.

Using Underwater Explosion and Cylinder Expansion Tests to Calibrate Afterburn Models for Aluminized Explosives

NASA Astrophysics Data System (ADS)

Wedberg, Rasmus

2017-06-01

The study explores the combined use of underwater performance tests and cylinder expansion tests in order to parameterize detonation models for aluminized explosives which exhibit afterburning. The approach is suggested to be used in conjunction with thermochemical computation. A formulation containing RDX and aluminum powder is considered and several charges with varying masses are submerged and detonated. Pressure gauges are employed at horizontal distances scaling with the charge diameter, and the specific shock wave energy is shown to increase with charge mass. This is attributed to the combustion of aluminum particles after the Chapman-Jouguet plane. Cylinder expansion tests are carried out using Photon Doppler Velocimetry to register the wall expansion velocity. The tests are modeled using a multi-material arbitrary Lagrangian-Eulerian approach with the Guirguis-Miller model describing detonation with afterburning. The equation of state and afterburn rate law parameters are adjusted such that the model reproduces the results from the cylinder expansion and underwater tests. The approach seems promising, and might be valuable for aluminized explosive formulations intended to be used in a variety of confinement conditions. Swedish Armed Forces.

Formation of Load Parameters of Destroyed Massife in Explosion of Multicharge Composition with Separation of its Parts by Profile Inert Interval

NASA Astrophysics Data System (ADS)

Paramonov, G. P.; Mysin, A. V.; Babkin, R. S.

2017-10-01

The paper introduces construction of multicharge composition with separation of parts by the profile inert interval. On the basis of the previous researches, the pulse-forming process at explosion of the borehole multicharge taking into account the offered design is considered. The physical model for definition of reflected wavelet taking into account an increment of radius of cross section of a charging cavity and the expiration of detonation products is offered. A technique is developed for numerical modeling of gas-dynamic processes in a borehole with a change in the axial channel of a profile inert interval caused by a high-temperature flow of gaseous products of an explosion. The authors obtained the dependence of the change in mean pressure on the borehole wall on time for each of the parts of the multicharge. To blast a series of charges of the proposed design, taking into account optimization of the stress fields of neighboring charges, the delay interval is determined for a short-delayed explosion.

Photodissociation of aligned CH3I and C6H3F2I molecules probed with time-resolved Coulomb explosion imaging by site-selective extreme ultraviolet ionization

PubMed Central

Amini, Kasra; Savelyev, Evgeny; Brauße, Felix; Berrah, Nora; Bomme, Cédric; Brouard, Mark; Burt, Michael; Christensen, Lauge; Düsterer, Stefan; Erk, Benjamin; Höppner, Hauke; Kierspel, Thomas; Krecinic, Faruk; Lauer, Alexandra; Lee, Jason W. L.; Müller, Maria; Müller, Erland; Mullins, Terence; Redlin, Harald; Schirmel, Nora; Thøgersen, Jan; Techert, Simone; Toleikis, Sven; Treusch, Rolf; Trippel, Sebastian; Ulmer, Anatoli; Vallance, Claire; Wiese, Joss; Johnsson, Per; Küpper, Jochen; Rudenko, Artem; Rouzée, Arnaud; Stapelfeldt, Henrik; Rolles, Daniel; Boll, Rebecca

2018-01-01

We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from a free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267 nm, the dominant reaction pathway in both molecules is neutral dissociation via cleavage of the carbon–iodine bond. This allows investigating the influence of the molecular environment on the absorption of an intense, femtosecond XUV pulse and the subsequent Coulomb explosion process. We find that the XUV probe pulse induces local inner-shell ionization of atomic iodine in dissociating iodomethane, in contrast to non-selective ionization of all photofragments in difluoroiodobenzene. The results reveal evidence of electron transfer from methyl and phenyl moieties to a multiply charged iodine ion. In addition, indications for ultrafast charge rearrangement on the phenyl radical are found, suggesting that time-resolved Coulomb explosion imaging is sensitive to the localization of charge in extended molecules. PMID:29430482

Photodissociation of aligned CH3I and C6H3F2I molecules probed with time-resolved Coulomb explosion imaging by site-selective extreme ultraviolet ionization.

PubMed

Amini, Kasra; Savelyev, Evgeny; Brauße, Felix; Berrah, Nora; Bomme, Cédric; Brouard, Mark; Burt, Michael; Christensen, Lauge; Düsterer, Stefan; Erk, Benjamin; Höppner, Hauke; Kierspel, Thomas; Krecinic, Faruk; Lauer, Alexandra; Lee, Jason W L; Müller, Maria; Müller, Erland; Mullins, Terence; Redlin, Harald; Schirmel, Nora; Thøgersen, Jan; Techert, Simone; Toleikis, Sven; Treusch, Rolf; Trippel, Sebastian; Ulmer, Anatoli; Vallance, Claire; Wiese, Joss; Johnsson, Per; Küpper, Jochen; Rudenko, Artem; Rouzée, Arnaud; Stapelfeldt, Henrik; Rolles, Daniel; Boll, Rebecca

2018-01-01

We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from a free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267 nm, the dominant reaction pathway in both molecules is neutral dissociation via cleavage of the carbon-iodine bond. This allows investigating the influence of the molecular environment on the absorption of an intense, femtosecond XUV pulse and the subsequent Coulomb explosion process. We find that the XUV probe pulse induces local inner-shell ionization of atomic iodine in dissociating iodomethane, in contrast to non-selective ionization of all photofragments in difluoroiodobenzene. The results reveal evidence of electron transfer from methyl and phenyl moieties to a multiply charged iodine ion. In addition, indications for ultrafast charge rearrangement on the phenyl radical are found, suggesting that time-resolved Coulomb explosion imaging is sensitive to the localization of charge in extended molecules.

Bonfire-safe low-voltage detonator

DOEpatents

Lieberman, M.L.

1988-07-01

A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half. 2 figs.

Bonfire-safe low-voltage detonator

DOEpatents

Lieberman, Morton L.

1990-01-01

A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half.

Photograph of Apollo 17 Lunar Roving Vehicle traverses

NASA Image and Video Library

1972-10-01

S72-03145 (October 1972) --- A vertical view of the Apollo 17 Taurus-Littrow site with an overlay to illustrate the three planned Apollo 17 traverses using the Lunar Roving Vehicle (LRV). The EVA-1 traverse has a single station (1); the EVA-2 traverse has four stations (2,3,4,5); and the EVA-3 traverse has five stations (6,7,8,9,10). Stations 10-A and 10-B are alternate locations for Station 10. In addition to the major stations mentioned above, brief stops are planned for sampling between stations using the LRV sampler tool (note diamond-shaped figures), and for deploying explosive charges associated with the Lunar Seismic Profiling Experiment (LSPE - note black x-marks).

The L = 6.6 Oosik barium plasma injection experiment and magnetic storm of March 7, 1972

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Murcray, W. B.; Peek, H. M.; Bottoms, P. J.

1975-01-01

A high-explosive shaped charge vaporizing a hollow conical liner of Ba metal and producing a fast field-aligned jet of plasma was detonated at high altitude, during a quiescent phase of a magnetic storm initiated by an ssc 10 hrs prior to the experiment, in an attempt to trace out and observe the dynamics of an auroral field line in the magnetosphere. Observations offer evidence for an upward Birkeland current sheet at the poleward edge of the auroral spiral of 8 x 10 to the minus second power A/m. Unusual features of the substorm leave open the possibility that the plasma injection may have triggered it.

Feasibility of an advanced thrust termination assembly for a solid propellant rocket motor

NASA Technical Reports Server (NTRS)

1975-01-01

A total of 68 quench tests were conducted in a vented bomb assembly (VBA). Designed to simulate full-scale motor operating conditions, this laboratory apparatus uses a 2-inch-diameter, end-burning propellant charge and an insulated disc of consolidated hydrated aluminum sulfate along with the explosive charge necessary to disperse the salt and inject it onto the burning surface. The VBA was constructed to permit variation of motor design parameters of interest; i.e., weight of salt per unit burning surface area, weight of explosive per unit weight of salt, distance from salt surface to burning surface, incidence angle of salt injection, chamber pressure, and burn time. Completely satisfactory salt quenching, without re-ignition, occurred in only two VBA tests. These were accomplished with a quench charge ratio (QCR) of 0.023 lb salt per square inch of burning surface at dispersing charge ratios (DCR) of 13 and 28 lb of salt per lb of explosive. Candidate materials for insulating salt charges from the rocket combustion environment were evaluated in firings of 5-inch-diameter, uncured end-burner motors. A pressed, alumina ceramic fiber material was selected for further evaluation and use in the final demonstration motor.

Communication: Two-step explosion processes of highly charged fullerene cations C{sub 60}{sup q+} (q = 20–60)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamazaki, Kaoru; Nakamura, Takashi; Kanno, Manabu

2014-09-28

To establish the fundamental understanding of the fragmentation dynamics of highly positive charged nano- and bio-materials, we carried out on-the-fly classical trajectory calculations on the fragmentation dynamics of C{sub 60}{sup q+} (q = 20–60). We used the UB3LYP/3-21G level of density functional theory and the self-consistent charge density-functional based tight-binding theory. For q ≥ 20, we found that a two-step explosion mechanism governs the fragmentation dynamics: C{sub 60}{sup q+} first ejects singly and multiply charged fast atomic cations C{sup z+} (z ≥ 1) via Coulomb explosions on a timescale of 10 fs to stabilize the remaining core cluster. Thermal evaporationsmore » of slow atomic and molecular fragments from the core cluster subsequently occur on a timescale of 100 fs to 1 ps. Increasing the charge q makes the fragments smaller. This two-step mechanism governs the fragmentation dynamics in the most likely case that the initial kinetic energy accumulated upon ionization to C{sub 60}{sup q+} by ion impact or X-ray free electron laser is larger than 100 eV.« less

Experimental study of detonation of large-scale powder-droplet-vapor mixtures

NASA Astrophysics Data System (ADS)

Bai, C.-H.; Wang, Y.; Xue, K.; Wang, L.-F.

2018-05-01

Large-scale experiments were carried out to investigate the detonation performance of a 1600-m3 ternary cloud consisting of aluminum powder, fuel droplets, and vapor, which were dispersed by a central explosive in a cylindrically stratified configuration. High-frame-rate video cameras and pressure gauges were used to analyze the large-scale explosive dispersal of the mixture and the ensuing blast wave generated by the detonation of the cloud. Special attention was focused on the effect of the descending motion of the charge on the detonation performance of the dispersed ternary cloud. The charge was parachuted by an ensemble of apparatus from the designated height in order to achieve the required terminal velocity when the central explosive was detonated. A descending charge with a terminal velocity of 32 m/s produced a cloud with discernably increased concentration compared with that dispersed from a stationary charge, the detonation of which hence generates a significantly enhanced blast wave beyond the scaled distance of 6 m/kg^{1/3}. The results also show the influence of the descending motion of the charge on the jetting phenomenon and the distorted shock front.

Numerical simulation of Composition B high explosive charge desensitization in gap test assembly after loading by precursor wave

NASA Astrophysics Data System (ADS)

Balagansky, I. A.; Stepanov, A. A.

2016-03-01

Results of numerical research into the desensitization of high explosive charges in water gap test-based experimental assemblies are presented. The experimental data are discussed, and the analysis using ANSYS AUTODYN 14.5 is provided. The desensitization phenomenon is well reproduced in numerical simulation using the JWL EOS and the Lee-Tarver kinetic equation for modeling of the initiation of heterogeneous high explosives with as well as without shock front waves. The analysis of the wave processes occurring during the initiation of the acceptor HE charge has been carried out. Peculiarities of the wave processes in the water gap test assemblies, which can influence the results of sensitivity measurement, have been studied. In particular, it has been established that precursor waves in the walls of the gap test assemblies can influence the detonation transmission distance.

V27 Test Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stofleth, Jerome H.; Tribble, Megan Kimberly; Crocker, Robert W.

2017-05-01

The V27 containment vessel was procured by the US Army Recovered Chemical Material Directorate ( RCMD ) as a replacement vessel for use on the P2 Explosive Destruction Systems. It is the third EDS vessel to be fabricated under Code Case 2564 of the ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels. The explosive rating for the vessel, based on the Code Case, is nine (9) pounds TNT - equivalent for up to 637 detonations . This report documents the results of explosive tests that were done on the vessel at Sandiamore » National Laboratories in Albuquerque New Mexico to qualify the vessel for explosive use . The primary qualification test consisted of si x 1.5 pound charges of Composition C - 4 (equivalent to 11.25 pounds TNT) distributed around the vessel in accordance with the User Design Specification. Four subsequent tests using less explosive evaluated the effects of slight variations in orientation of the charges . All vessel acceptance criteria were met.« less

Laser Simulations of the Destructive Impact of Nuclear Explosions on Hazardous Asteroids

NASA Astrophysics Data System (ADS)

Aristova, E. Yu.; Aushev, A. A.; Baranov, V. K.; Belov, I. A.; Bel'kov, S. A.; Voronin, A. Yu.; Voronich, I. N.; Garanin, R. V.; Garanin, S. G.; Gainullin, K. G.; Golubinskii, A. G.; Gorodnichev, A. V.; Denisova, V. A.; Derkach, V. N.; Drozhzhin, V. S.; Ericheva, I. A.; Zhidkov, N. V.; Il'kaev, R. I.; Krayukhin, A. A.; Leonov, A. G.; Litvin, D. N.; Makarov, K. N.; Martynenko, A. S.; Malinov, V. I.; Mis'ko, V. V.; Rogachev, V. G.; Rukavishnikov, A. N.; Salatov, E. A.; Skorochkin, Yu. V.; Smorchkov, G. Yu.; Stadnik, A. L.; Starodubtsev, V. A.; Starodubtsev, P. V.; Sungatullin, R. R.; Suslov, N. A.; Sysoeva, T. I.; Khatunkin, V. Yu.; Tsoi, E. S.; Shubin, O. N.; Yufa, V. N.

2018-01-01

We present the results of preliminary experiments at laser facilities in which the processes of the undeniable destruction of stony asteroids (chondrites) in space by nuclear explosions on the asteroid surface are simulated based on the principle of physical similarity. We present the results of comparative gasdynamic computations of a model nuclear explosion on the surface of a large asteroid and computations of the impact of a laser pulse on a miniature asteroid simulator confirming the similarity of the key processes in the fullscale and model cases. The technology of fabricating miniature mockups with mechanical properties close to those of stony asteroids is described. For mini-mockups 4-10 mm in size differing by the shape and impact conditions, we have made an experimental estimate of the energy threshold for the undeniable destruction of a mockup and investigated the parameters of its fragmentation at a laser energy up to 500 J. The results obtained confirm the possibility of an experimental determination of the criteria for the destruction of asteroids of various types by a nuclear explosion in laser experiments. We show that the undeniable destruction of a large asteroid is possible at attainable nuclear explosion energies on its surface.

Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

PubMed

Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

2014-01-01

Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices.

The Small Carry-on Impactor (SCI) and the Hayabusa2 Impact Experiment

NASA Astrophysics Data System (ADS)

Saiki, T.; Imamura, H.; Arakawa, M.; Wada, K.; Takagi, Y.; Hayakawa, M.; Shirai, K.; Yano, H.; Okamoto, C.

2017-07-01

Hayabusa2 is a sample return mission of JAXA launched on 3 December 2014. Hayabusa2 is the successor of Hayabusa, which returned samples from the asteroid Itokawa to the Earth. Although the design of Hayabusa2 follows that of Hayabusa, the former is equipped with some new components. The small carry-on impactor (SCI) is one of those components. The SCI is a compact kinetic impactor designed to remove the asteroid surface regolith locally and create an artificial crater. One of the most important scientific objectives of Hayabusa2 is to investigate the chemical and physical properties of the internal materials and structures of the target body, asteroid Ryugu. Hayabusa2 will attempt to observe the resultant crater with some scientific instruments and to get samples from around the crater. High kinetic energy is required to create a meaningful crater, however, the impact system design needs to fit within strict constraints. Complicated functions, such as a guidance and control system, are not permitted. A special type of shaped charge is used for the acceleration of the impactor of the SCI in order to make system simpler. Using this explosion technique makes it possible to accelerate the impactor very quickly and to hit the asteroid without a guidance system. However, the impact operation will be complicated because the explosive is very powerful and it scatters high-speed debris at the detonation. This paper describes an overview of the SCI system, the results of the development testing and an outline of the impact experiment of the Hayabusa2 mission.

Small carry-on impactor of Hayabusa2 mission

NASA Astrophysics Data System (ADS)

Saiki, Takanao; Sawada, Hirotaka; Okamoto, Chisato; Yano, Hajime; Takagi, Yasuhiko; Akahoshi, Yasuhiro; Yoshikawa, Makoto

2013-03-01

A Japanese spacecraft, Hayabusa2, the successor of Hayabusa, which came back from the Asteroid Itokawa with sample materials after its 7-year-interplanetary journeys, is a current mission of Japan Aerospace Exploration Agency (JAXA) and scheduled to be launched in 2014. Although its design basically follows Hayabusa, some new components are planned to be equipped in Hayabusa2 mission. A Small Carry-on Impactor (SCI), a small explosive device, is one of the challenges that were not seen with Hayabusa. An important scientific objective of Hayabusa2 is to investigate chemical and physical properties of the internal materials and structures. SCI creates an artificial crater on the surface of the asteroid and the mother spacecraft observes the crater and tries to get sample materials. High kinetic energy is required to creating a meaningful crater. The SCI would become complicated and heavy if the traditional acceleration devices like thrusters and rocket motors are used to hit the asteroid because the acceleration distance is quite large and guidance system is necessary. In order to make the system simpler, a technology of special type of shaped charge is used for the acceleration of the impact head. By using this technology, it becomes possible to accelerate the impact head very quickly and to hit the asteroid without guidance system. However, the impact operation should be complicated because SCI uses powerful explosive and it scatters high speed debris at the detonation. This paper presents the overview of our new small carry-on impact system and the impact operation of Hayabusa2 mission.

Ion-coincidence momentum imaging of three-body Coulomb explosion of formaldehyde in ultrashort intense laser fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fushitani, M.; Matsuda, A.; Hishikawa, A., E-mail: hishi@chem.nagoya-u.ac.jp

Three-body Coulomb explosion of formaldehyde (H{sub 2}CO) in intense 7- and 35-fs laser fields (1.3 × 10{sup 15} W/cm{sup 2}) has been investigated by using ion-coincidence momentum imaging technique. Two types of explosion pathways from the triply charged state, H{sub 2}CO{sup 3+} → (i) H{sup +} + H{sup +} + CO{sup +} and (ii) H{sup +} + CH{sup +} + O{sup +}, have been identified. It is shown from the momentum correlation of the fragment ions of pathway (i), that the geometrical structure of the molecule is essentially frozen along the H-C-H bending coordinate for the 7-fs case. On the othermore » hand, for a longer pulse duration (35 fs), structural deformation along the C-H stretching and H-C-H bending coordinates is identified, which is ascribed to the nuclear dynamics in the dication states populated within the laser pulse duration.« less

High temperature detonator

DOEpatents

Johnson, James O.; Dinegar, Robert H.

1988-01-01

A detonator assembly is provided which is usable at high temperatures about 300.degree. C. A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive. A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge.

FROM THE HISTORY OF PHYSICS: The extraordinarily beautiful physical principle of thermonuclear charge design (on the occasion of the 50th anniversary of the test of RDS-37 — the first Soviet two-stage thermonuclear charge)

NASA Astrophysics Data System (ADS)

Goncharov, German A.

2005-11-01

On 22 November 1955, the Semipalatinsk test site saw the test of the first domestic two-stage thermonuclear RDS-37 charge. The charge operation was based on the principle of radiation implosion. The kernel of the principle consists in the radiation generated in a primary A-bomb explosion and confined by the radiation-opaque casing propagating throughout the interior casing volume and flowing around the secondary thermonuclear unit. The secondary unit experiences a strong compression under the irradiation, with a resulting nuclear and thermonuclear explosion. The RDS-37 explosion was the strongest of all those ever realized at the Semipalatinsk test site. It produced an indelible impression on the participants in the test. This document-based paper describes the genesis of the ideas underlying the RDS-37 design and reflects the critical moments in its development. The advent of RDS-37 was an outstanding accomplishment of the scientists and engineers of our country.

Explosive plane-wave lens

DOEpatents

Marsh, Stanley P.

1988-01-01

An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

Explosive plane-wave lens

DOEpatents

Marsh, S.P.

1988-03-08

An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 4 figs.

Nebular Phase Spectra of SNe Ia from the CSP2 Sample

NASA Astrophysics Data System (ADS)

Diamond, Tiara; Carnegie Supernova Project II

2018-06-01

We present a comparison of late-time spectra in the near-infrared for some of the Type Ia supernovae from the Carnegie Supernova Project II. Particular attention is paid to the shape and evolution of several emission features, including the [Fe II] line at 1.6440 μm. We put our findings in context of several explosion scenarios and progenitor systems.

Highly efficient SERS substrate for direct detection of explosive TNT using popcorn-shaped gold nanoparticle-functionalized SWCNT hybrid.

PubMed

Demeritte, Teresa; Kanchanapally, Rajashekhar; Fan, Zhen; Singh, Anant Kumar; Senapati, Dulal; Dubey, Madan; Zakar, Eugene; Ray, Paresh Chandra

2012-11-07

This paper reports for the first time the development of a large-scale SERS substrate from a popcorn-shaped gold nanoparticle-functionalized single walled carbon nanotubes hybrid thin film for the selective and highly sensitive detection of explosive TNT material at a 100 femtomolar (fM) level.

All Prime Contract Awards by State or Country, Place, and Contractor, FY83, Part 5 (LaGrange, Indiana-Escanaba, Michigan).

DTIC Science & Technology

1983-01-01

N00104-83-CA014 B C A 1 2 2 1361 000 AS DEPTH CHARGE EXPLOSIVE COMPO 8 A 3 4 J 018 1 B J 1 J 174 2 E JA116 4000 N00104-83-CA014 B C A 1 2 2 1386 000 A6... EXPLOSIVE ORD DISPOSAL TOOL- 8 A 6 4 J 018 1 B J 1 E 84 2 A JA116 1398 N00104-63-CA026 B C A 1 3 2 1361 000 AS DEPTH CHARGE EXPLOSIVE COMPO 8 A 3 4 J...CA088 B C A 1 2 2 1356 000 AS TORPEDO EXPLOSIVE COMPONENTS 8 A 3 5 A 1001 5 B J 1 H 195 2 G PAIOt A700 N00140-83-CBA83 B C Z 1 2 2 R414 000 51 MOT

Minimisation of the explosion shock wave load onto the occupants inside the vehicle during trinitrotoluene charge blast.

PubMed

Krzystała, Edyta; Mężyk, Arkadiusz; Kciuk, Sławomir

2016-01-01

The aim of this study was to elaborate identification method of crew overload as a result of trinitrotoluene charge explosion under the military wheeled vehicle. During the study, an experimental military ground research was carried out. The aim of this research was to verify the mine blast resistance of the prototype wheeled vehicle according to STANG 4569 as well as the anti-explosive seat. Within the work, the original methodology was elaborated along with a prototype research statement. This article presents some results of the experimental research, thanks to which there is a possibility to estimate the crew's lives being endangered in an explosion through the measurement of acceleration as well as the pressure on the chest, head and internal organs. On the basis of our acceleration results, both effectiveness and infallibility of crew protective elements along with a blast mitigation seat were verified.

Measurement of Detonation Velocity for a Nonideal Heterogeneous Explosive in Axisymmetric and Two-Dimensional Geometries

NASA Astrophysics Data System (ADS)

Higgins, Andrew

2009-12-01

Detonation in a heterogeneous explosive with a relatively sparse concentration of reaction centers ("hot spots") is investigated experimentally. The explosive system considered is nitromethane gelled with PMMA and with glass microballoons (GMB's) in suspension. The detonation velocity is measured as a function of the characteristic charge dimension (diameter or thickness) in both axisymmetric and two-dimensional geometries. The use of a unique, annular charge geometry (with the diameter of the annulus much greater than the annular gap thickness) permits quasi-two-dimensional detonations to be observed without undesirable lateral rarefactions that result from a finite aspect ratio. The results confirm the prior findings of Gois et al. (1996) which show that, for a low concentration of GMB's, detonation propagation does not exhibit the expected 2:1 scaling from axisymmetric to planar geometries. This reinforces the idea that detonation in highly nonideal explosives is not governed exclusively by global front curvature.

Ground motion analysis of OSSY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swift, R.P.; Snell, C.M.

1993-11-01

The On Site Seismic Yield experiment, OSSY, was performed to investigate the viability of a high-explosive technique to help estimate the yield of nuclear explosions. We have analyzed recorded data and conducted numerical simulations of the 100-pound OSSY experiments performed in hole UE-10 ITS No. 3 at the Nevada Test Site. Particle velocity wave forms from these experiments show a distinct dual-pulse structure in the close-in and far-field regions, with the amplitude of the second pulse being as large as or larger than the first pulse. To gain some insight into the cause of the dual-pulse feature, we examine howmore » the explosion-induced close-in response is affected by (1) certain features of inelastic rock/soil constitutive models applied in the near-field region, (2) the large length-to-diameter charge ratio of 8, (3) the charge and gauge package emplacement, and (4) geology (e.g., layering) in the vicinity of the explosion. Our results from 1-D and 2-D simulations show the following: (a) the response, measured by accelerometers located above the charges, is significantly influenced by the charge length-to-diameter ratio out to a distance of 8 m. (b) the grout emplacement of the charge has very little effect on the response. (c) the geologic layering serves mainly to phase the arrival of the pulses. (d) the second pulse can be best accounted for by applying a dilatant feature that allows for pore recovery during unloading. Other material property variations do not provide any contribution to the formation of a second pulse.« less

An Experimental study of Corner Turning in a Granular Ammonium Nitrate Based Explosive

NASA Astrophysics Data System (ADS)

Sorber, Susan; Taylor, Peter

2007-06-01

A novel experimental geometry has been designed to perform controlled studies of corner turning in a ``tap density'' granular explosive. It enables the study of corner turning and detonation properties with high speed framing camera, piezo probes and ionization probes. The basic geometry consists of a large diameter PMMA cylinder filled with the granular explosive which is initiated on axis from below by a smaller diameter cylinder of the same explosive or a booster charge. Four experiments have been performed on a granular Ammonium Nitrate based non ideal explosive (NIE). Two experiments were initiated directly from a PE4 booster charge and two were initiated from a train including a booster charge and a 1'' diameter Copper cylinder containing the same NIE. Data from the four experiments was reproducible and observed detonation and shock waves showed good 2-D symmetry. Detonation phase velocity on the vertical side of the main container was observed and both shock and detonation velocities were observed in the corner turning region along the base of the main container. Analysis of the data shows that the booster initiated geometries with a higher input shock pressure into the NIE gave earlier detonation arrival at the lowest probes on the container side. The corner turning data is compared to a hydrocode calculation using a simple JWL++ reactive burn model.

Improvement on thermal performance of a disk-shaped miniature heat pipe with nanofluid

PubMed Central

2011-01-01

The present study aims to investigate the effect of suspended nanoparticles in base fluids, namely nanofluids, on the thermal resistance of a disk-shaped miniature heat pipe [DMHP]. In this study, two types of nanoparticles, gold and carbon, in aqueous solution are used respectively. An experimental system was set up to measure the thermal resistance of the DMHP with both nanofluids and deionized [DI] water as the working medium. The measured results show that the thermal resistance of DMHP varies with the charge volume and the type of working medium. At the same charge volume, a significant reduction in thermal resistance of DMHP can be found if nanofluid is used instead of DI water. PMID:22082052

Thermodynamic States in Explosion Fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhl, A L

2010-03-12

We investigate the thermodynamic states occurring in explosion fields from condensed explosive charges. These states are often modeled with a Jones-Wilkins-Lee (JWL) function. However, the JWL function is not a Fundamental Equation of Thermodynamics, and therefore cannot give a complete specification of such states. We use the Cheetah code of Fried to study the loci of states of the expanded detonation products gases from C-4 charges, and their combustion products air. In the Le Chatelier Plane of specific-internal-energy versus temperature, these loci are fit with a Quadratic Model function u(T), which has been shown to be valid for T

Ultrafast Coulomb explosion of a diiodomethane molecule induced by an X-ray free-electron laser pulse.

PubMed

Takanashi, Tsukasa; Nakamura, Kosuke; Kukk, Edwin; Motomura, Koji; Fukuzawa, Hironobu; Nagaya, Kiyonobu; Wada, Shin-Ichi; Kumagai, Yoshiaki; Iablonskyi, Denys; Ito, Yuta; Sakakibara, Yuta; You, Daehyun; Nishiyama, Toshiyuki; Asa, Kazuki; Sato, Yuhiro; Umemoto, Takayuki; Kariyazono, Kango; Ochiai, Kohei; Kanno, Manabu; Yamazaki, Kaoru; Kooser, Kuno; Nicolas, Christophe; Miron, Catalin; Asavei, Theodor; Neagu, Liviu; Schöffler, Markus; Kastirke, Gregor; Liu, Xiao-Jing; Rudenko, Artem; Owada, Shigeki; Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Yabashi, Makina; Kono, Hirohiko; Ueda, Kiyoshi

2017-08-02

Coulomb explosion of diiodomethane CH 2 I 2 molecules irradiated by ultrashort and intense X-ray pulses from SACLA, the Japanese X-ray free electron laser facility, was investigated by multi-ion coincidence measurements and self-consistent charge density-functional-based tight-binding (SCC-DFTB) simulations. The diiodomethane molecule, containing two heavy-atom X-ray absorbing sites, exhibits a rather different charge generation and nuclear motion dynamics compared to iodomethane CH 3 I with only a single heavy atom, as studied earlier. We focus on charge creation and distribution in CH 2 I 2 in comparison to CH 3 I. The release of kinetic energy into atomic ion fragments is also studied by comparing SCC-DFTB simulations with the experiment. Compared to earlier simulations, several key enhancements are made, such as the introduction of a bond axis recoil model, where vibrational energy generated during charge creation processes induces only bond stretching or shrinking. We also propose an analytical Coulomb energy partition model to extract the essential mechanism of Coulomb explosion of molecules from the computed and the experimentally measured kinetic energies of fragment atomic ions by partitioning each pair Coulomb interaction energy into two ions of the pair under the constraint of momentum conservation. Effective internuclear distances assigned to individual fragment ions at the critical moment of the Coulomb explosion are then estimated from the average kinetic energies of the ions. We demonstrate, with good agreement between the experiment and the SCC-DFTB simulation, how the more heavily charged iodine fragments and their interplay define the characteristic features of the Coulomb explosion of CH 2 I 2 . The present study also confirms earlier findings concerning the magnitude of bond elongation in the ultrashort X-ray pulse duration, showing that structural damage to all but C-H bonds does not develop to a noticeable degree in the pulse length of ∼10 fs.

Numerical investigation of particle-blast interaction during explosive dispersal of liquids and granular materials

NASA Astrophysics Data System (ADS)

Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.

2018-05-01

Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase flow generated during explosive particle dispersal indicates that the particle momentum flux is the dominant term in the near field. Both the gas and particle loading must be taken into account when determining the damage to nearby structures following the detonation of a high-explosive charge surrounded by a material layer.

Numerical investigation of particle-blast interaction during explosive dispersal of liquids and granular materials

NASA Astrophysics Data System (ADS)

Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.

2018-04-01

Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase flow generated during explosive particle dispersal indicates that the particle momentum flux is the dominant term in the near field. Both the gas and particle loading must be taken into account when determining the damage to nearby structures following the detonation of a high-explosive charge surrounded by a material layer.

Acoustic source signal and directivity for explosive sources in complex environments

NASA Astrophysics Data System (ADS)

Waxler, R.; Bonner, J. L.; Reinke, R.; Talmadge, C. L.; Kleinert, D. E.; Alberts, W.; Lennox, E.

2012-12-01

Much work has gone into characterizing the blast wave, and ultimate acoustic pulse, produced by an explosion in flat, open land. Recently, an experiment was performed to study signals produced by explosions in more complex environments, both above and below ground. Explosive charges, ranging in weight from 200 to 2000 lbs., were detonated in a variety of configurations in and around tubes and culverts as well as buried in alluvium and limestone. A large number of acoustic sensors were deployed to capture the signals from the explosions. The deployment included two concentric rings of eighteen sensors each, spaced roughly every twenty degrees at radii of 300 and 1000 meters and surrounding the explosions. These captured the acoustic source function and directivity. In addition, a network of sensors, including sensors mounted on an aerostat and elevated to 300 meters altitude, were deployed throughout the area to capture the signals as they propagated. The meteorological state was monitored with a variety of instruments including a tethersonde, radiosonde and sodar. Significant directivity was observed in the signals from many of the shots, including those from charges that were detonated underground, but not near any structure. Results from the experiment will be presented.

Electric generator

DOEpatents

Foster, Jr., John S.; Wilson, James R.; McDonald, Jr., Charles A.

1983-01-01

1. In an electrical energy generator, the combination comprising a first elongated annular electrical current conductor having at least one bare surface extending longitudinally and facing radially inwards therein, a second elongated annular electrical current conductor disposed coaxially within said first conductor and having an outer bare surface area extending longitudinally and facing said bare surface of said first conductor, the contiguous coaxial areas of said first and second conductors defining an inductive element, means for applying an electrical current to at least one of said conductors for generating a magnetic field encompassing said inductive element, and explosive charge means disposed concentrically with respect to said conductors including at least the area of said inductive element, said explosive charge means including means disposed to initiate an explosive wave front in said explosive advancing longitudinally along said inductive element, said wave front being effective to progressively deform at least one of said conductors to bring said bare surfaces thereof into electrically conductive contact to progressively reduce the inductance of the inductive element defined by said conductors and transferring explosive energy to said magnetic field effective to generate an electrical potential between undeformed portions of said conductors ahead of said explosive wave front.

Fundamental Research in Explosive Magnetohydrodynamics

DTIC Science & Technology

1976-02-01

nearly 1 Torr. For repe- titive pulsing at the rate of several per second, a giant vacuum pumping system would be required to evacuate about 50 m of... pumping system. The need for a superccnductinq magnet arises from the desire to moke. the oxplosive charge a reasonable tticknass. The pulse duration...NDiTO *133 I WINDINGS S~EXPLOSIVE CHARGE S. 80 Kg REPLACEABLE~~DIAPHRA•M ! p I or OF IRON 500 COAXIAL V MAGNET CABLES TO PUMP YOKE FLASH LAMPS IRON

Metal parts hydrosized by explosive force

NASA Technical Reports Server (NTRS)

1965-01-01

Large metal parts are sized by a charge exploded above a sealed container filled with evacuated die and water. Explosive hydrosizing achieves close dimensional tolerances, eliminates damage to the surface, and allows longer force application and more even pressure distribution.

Explosive Spot Joining of Metals

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Perry, Ronnie B. (Inventor)

1997-01-01

The invention is an apparatus and method for wire splicing using an explosive joining process. The apparatus consists of a prebend, U-shaped strap of metal that slides over prepositioned wires. A standoff means separates the wires from the strap before joining. An adhesive means holds two ribbon explosives in position centered over the U-shaped strap. A detonating means connects to the ribbon explosives. The process involves spreading strands of each wire to be joined into a flat plane. The process then requires alternating each strand in alignment to form a mesh-like arrangement with an overlapped area. The strap slides over the strands of the wires. and the standoff means is positioned between the two surfaces. The detonating means then initiates the ribbon explosives that drive the strap to accomplish a high velocity. angular collision between the mating surfaces. This collision creates surface melts and collision bonding resulting in electron-sharing linkups.

Permanent wire splicing by an explosive joining process

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Kushnick, Anne C. (Inventor)

1991-01-01

The invention is an apparatus and method for wire splicing using an explosive joining process. The apparatus consists of a prebent, U-shaped strap of metal that slides over prepositioned wires. A standoff means separates the wires from the strap before joining. An adhesive means holds two ribbon explosives in position centered over the U-shaped strap. A detonating means connects to the ribbon explosives. The process involves spreading strands of each wire to be joined into a flat plane. The process then requires alternating each strand in alignment to form a mesh-like arrangement with an overlapped area. The strap slides over the strands of the wires, and the standoff means is positioned between the two surfaces. The detonating means then initiates the ribbon explosives that drive the strap to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and collision bonding results in electron sharing linkups.

Explosive plane-wave lens

DOEpatents

Marsh, S.P.

1987-03-12

An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 3 figs., 3 tabs.

Determination of detonation parameters for liquid High Explosives

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander

2011-06-01

The experimental investigation of detonation parameters and reaction zone structure in liquid HE (bis-(2-fluoro-2,2-dinitroethyl)formal (FEFO), tetranitromethane (TNM), nitromethane (NM)) was conducted. Detonation front in TNM and NM was stable while the instability of detonation in FEFO was observed. Von Neumann spike was recorded for these HE and its parameters were determined. The different methods for C-J point determination were used for each HE. For FEFO reaction time τ was found from experiments with different charge diameters (τ is approximately equal to 300 ns); for TNM - at fixed diameter and different lengths of charges (τ ~ 200 ns); for NM - at fixed diameter and length of charges, but detonation initiation was carried out by different explosive charges (τ ~ 50 ns). It was found that in TNM the detonation velocity depends on charge diameter. Maximum value of reaction rate in investigated liquid HE was observed after shock jump and induction time was not recorded.

Determination of detonation parameters for liquid high explosives

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander

2012-03-01

The experimental investigation of detonation parameters and reaction zone structure in liquid HE (bis-(2-fluoro-2,2-dinitroethyl)formal (FEFO), tetranitromethane (TNM), nitromethane (NM)) was conducted by means of laser interferometer VISAR. Detonation front in TNM and NM was stable while the instability of detonation in FEFO was observed. The parameters of Von Neumann spike were determined for these HE. The different methods for C-J point determination were used for each HE. For FEFO reaction time t was found from experiments with different charge diameters (τ is approximately equal to 300 ns); for TNM - at fixed diameter and different lengths of charges (τ ≈ 200 ns); for NM - at fixed diameter and length of charges, but detonation initiation was carried out by different explosive charges (τ ≈ 50 ns). It was found that in TNM the detonation velocity depends on charge diameter. Maximum value of reaction rate in investigated liquid HE was observed after shock jump.

Air Blasts from Cased and Uncased Explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glenn, L. A.

2016-04-12

The problem of a spherical blast in air is solved using the STUN code. For bare charges, the calculations are shown to be in excellent agreement with previous published results. It is demonstrated that, for an unconfined (uncased) chemical explosive, both range and time to effect scale inversely as the cube root of the yield and directly as the cube root of the ambient air density. It is shown that the peak overpressure decays to roughly 1/10 of ambient pressure in a scaled range of roughly 10 m/kg 1/3 at sea level. At a height of 30 km, where themore » ambient density is a factor of 64 less, the range to the same decay increases to 40 m/kg 1/3 . As a direct result of the scaling a single calculation suffices for all charge sizes and altitudes. Although the close-in results are sensitive to the nature of the explosive source and the equation of state of the air, this sensitivity is shown to virtually disappear at scaled ranges > 0.5 m/kg 1/3 . For cased explosives the case thickness introduces an additional scale factor. Moreover, when the blast wave arrives at the inner case radius the case begins to expand. Fracture occurs when a critical value of the resulting hoop strain is reached, causing the case to shatter into fragments. A model is proposed to describe the size distribution of the fragments and their subsequent motion via drag interaction with the explosion products and ambient air. It is shown that a significant fraction of the charge energy is initially transmitted to the case fragments in the form of kinetic energy; for example, a 1 kg spherical charge with a 5 mm thick steel case has almost 29% of the total charge energy as initial kinetic energy of case fragments. This percentage increases with increasing case thickness and decreases with increasing charge size. The peak overpressure at a given range is 70-85% for cased explosives as compared with uncased and the peak impulse per unit area is 90-95%. The peak overpressure and impulse also decrease rapidly with altitude. The effect of the fragments is to increase lethality. Whereas at a scaled range of 10 m/kg 1/3 , the peak overpressure is an order of magnitude less than the ambient pressure, the number of fragments per unit area is close to 1 m -2 /kg 1/3 , independent of case thickness or altitude. For sufficient ratio of case-to- explosive mass, the number of fragments scales with the cube root of the yield and is independent of case thickness.« less

Modeling of Small Martian Volcanoes: A Changing View of Volcanic Shield and Cone Fields

NASA Astrophysics Data System (ADS)

Sakimoto, S. E.; Bradley, B. A.; Garvin, J. B.

2001-05-01

The small volcanic features on Mars (channels, flows, shields, and cratered cones) are key to understanding eruption styles, rates, and volumes because they are ubiquitous and simple enough to attempt modeling. Several of these small features have been suggested to be geologically recent [1,2,3]. This study measures and models small (3-50 km) volcanic edifices. Recent Mars Global Surveyor data reveal that these small features are more common that we had previously thought from the lower resolution Viking mission data (e.g., [3,4]). Furthermore, there are clear geometric differences in the Mars Orbiter Laser Altimeter (MOLA) data between regions suggesting local and regional eruption styles may vary with latitude. While a few of the pre-MGS construction models predict the martian mid-latitude volcanic shield shapes fairly well, the small explosive volcanic edifice shapes were not well predicted by existing models (see[5]), and there are a host of types-mostly polar-that are not well described by prior modeling. We compare small edifice construction model results for a percolation style model of effusive and mixed effusive and explosive edifices to prior model results for several martian volcanic regions. While mid-latitude edifices match well to predicted cross-section shapes, steeper flank slopes (See [6]; Glaze and Sakimoto, this volume) for the polar edifices suggest that the magma supply rate or the edifice permeability may be higher in the polar regions for some edifices types. However, polar edifice flank slopes do not commonly reach the greater than 10 degree flanks expected from prior explosive edifice models. Additionally, we do not observe shallow flank slope shields in the polar regions. This suggests that simple shield building may be significantly influenced or modified by volatile involvement near the martian poles, while a range of poorly understood explosive activity may be active in both regions. [1] Keszthelyi et al. JGR 105, 15027-15049, 2000. [2] Hartmann and Berman, JGR, 105, 15011-15025, 2000. [3] Garvin, et al., Icarus, 145, 648-652, 2000. [4] Sakimoto, et al., LPSC XXXII, CDROM, abstract #1808, 2001. [5] Glaze and Baloga LPSC XXXII, CDROM, abstract #1209, 2001. [6] Wong, et al., LPSC XXXII, CDROM, abstract #1563, 2001.

Totally confined explosive welding. [apparatus to reduce noise level and protect personnel during explosive bonding

NASA Technical Reports Server (NTRS)

Bement, L. J. (Inventor)

1974-01-01

A method and associated apparatus for confining the undesirable by-products and limiting noise of explosive welding are discussed. The apparatus consists fo a simple enclosure into which the explosive is placed and within which the explosion occurs. The shape of the enclosure, the placement of the explosive, and the manner in which the enclosure is placed upon the material to be welded determine the force of the explosion transmitted to the proposed bond area. The explosion is totally confined within the enclosure thus reducing the noise level and preventing debris from being strewn about to contaminate the weld area or create personnel hazards.

Explosion and Final State of an Unstable Reissner-Nordström Black Hole.

PubMed

Sanchis-Gual, Nicolas; Degollado, Juan Carlos; Montero, Pedro J; Font, José A; Herdeiro, Carlos

2016-04-08

A Reissner-Nordström black hole (BH) is superradiantly unstable against spherical perturbations of a charged scalar field enclosed in a cavity, with a frequency lower than a critical value. We use numerical relativity techniques to follow the development of this unstable system-dubbed a charged BH bomb-into the nonlinear regime, solving the full Einstein-Maxwell-Klein-Gordon equations, in spherical symmetry. We show that (i) the process stops before all the charge is extracted from the BH, and (ii) the system settles down into a hairy BH: a charged horizon in equilibrium with a scalar field condensate, whose phase is oscillating at the (final) critical frequency. For a low scalar field charge q, the final state is approached smoothly and monotonically. For large q, however, the energy extraction overshoots, and an explosive phenomenon, akin to a bosenova, pushes some energy back into the BH. The charge extraction, by contrast, does not reverse.

Solid explosive plane-wave lenses pressed-to-shape with dies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olinger, B.

2007-11-01

Solid-explosive plane-wave lenses 1", 2" and 4¼" in diameter have been mass-produced from components pressed-to-shape with aluminum dies. The method used to calculate the contour between the solid plane-wave lens components pressed-to-shape with the dies is explained. The steps taken to press, machine, and assemble the lenses are described. The method of testing the lenses, the results of those tests, and the corrections to the dies are reviewed. The work on the ½", 8", and 12" diameter lenses is also discussed.

Interplay of explosive thermal reaction dynamics and structural confinement

NASA Astrophysics Data System (ADS)

Perry, W. Lee; Zucker, Jonathan; Dickson, Peter M.; Parker, Gary R.; Asay, Blaine W.

2007-04-01

Explosives play a significant role in human affairs; however, their behavior in circumstances other than intentional detonation is poorly understood. Accidents may have catastrophic consequences, especially if additional hazardous materials are involved. Abnormal ignition stimuli, such as impact, spark, friction, and heat may lead to a very violent outcome, potentially including detonation. An important factor influencing the behavior subsequent to abnormal ignition is the strength and inertia of the vessel confining the explosive, i.e., the near-field structural/mechanical environment, also known as confinement (inertial or mechanical). However, a comprehensive and quantified understanding of how confinement affects reaction violence does not yet exist. In the research discussed here, we have investigated a wide range of confinement conditions and related the explosive response to the fundamentals of the combustion process in the explosive. In our experiments, a charge of an octahydrotetranitrotetrazine-based plastic bonded explosive (PBX 9501) was loaded into a gun assembly having variable confinement conditions and subjected to a heating profile. The exploding charge breached the confinement and accelerated a projectile down the gun barrel. High bandwidth pressure and volume measurements were made and a first-law analysis was used to obtain enthalpy and power from the raw data. These results were then used to quantify reaction violence. Enthalpy change and power ranged from 0-1.8 kJ and 0-12 MW for 300 mg charges, respectively. Below a confinement strength of 20 MPa, violence was found to decline precipitously with decreasing confinement, while the violence for the heaviest confinement experiments was found to be relatively constant. Both pressure and pressurization rate were found to have critical values to induce and sustain violent reaction.

Multichannel Discriminative Detection of Explosive Vapors with an Array of Nanofibrous Membranes Loaded with Quantum Dots.

PubMed

Wu, Zhaofeng; Duan, Haiming; Li, Zhijun; Guo, Jixi; Zhong, Furu; Cao, Yali; Jia, Dianzeng

2017-11-20

The multichannel fluorescent sensor array based on nanofibrous membranes loaded with ZnS quantum dots (QDs) was created and demonstrated for the discriminative detection of explosives. The synergistic effect of the high surface-to-volume ratio of QDs, the good permeability of nanofibrous membranes and the differential response introduced by surface ligands was played by constructing the sensing array using nanofibrous membranes loaded with ZnS QDs featuring several surface ligands. Interestingly, although the fluorescence quenching of the nanofibrous membranes is not linearly related to the exposure time, the fingerprint of each explosive at different times is very similar in shape, and the fingerprints of the three explosives show different shapes. Three saturated vapors of nitroaromatic explosives could be reliably detected and discriminated by the array at room temperature. This work is the first step toward devising a monitoring system for explosives in the field of public security and defense. It could, for example, be coupled with the technology of image recognition and large data analysis for a rapid diagnostic test of explosives. This work further highlights the power of differential, multichannel arrays for the rapid and discriminative detection of a wide range of chemicals.

Multichannel Discriminative Detection of Explosive Vapors with an Array of Nanofibrous Membranes Loaded with Quantum Dots

PubMed Central

Wu, Zhaofeng; Duan, Haiming; Li, Zhijun; Guo, Jixi; Zhong, Furu; Cao, Yali; Jia, Dianzeng

2017-01-01

The multichannel fluorescent sensor array based on nanofibrous membranes loaded with ZnS quantum dots (QDs) was created and demonstrated for the discriminative detection of explosives. The synergistic effect of the high surface-to-volume ratio of QDs, the good permeability of nanofibrous membranes and the differential response introduced by surface ligands was played by constructing the sensing array using nanofibrous membranes loaded with ZnS QDs featuring several surface ligands. Interestingly, although the fluorescence quenching of the nanofibrous membranes is not linearly related to the exposure time, the fingerprint of each explosive at different times is very similar in shape, and the fingerprints of the three explosives show different shapes. Three saturated vapors of nitroaromatic explosives could be reliably detected and discriminated by the array at room temperature. This work is the first step toward devising a monitoring system for explosives in the field of public security and defense. It could, for example, be coupled with the technology of image recognition and large data analysis for a rapid diagnostic test of explosives. This work further highlights the power of differential, multichannel arrays for the rapid and discriminative detection of a wide range of chemicals. PMID:29156627

Generation of Low-Energy High-Current Electron Beams in Plasma-Anode Electron Guns

NASA Astrophysics Data System (ADS)

Ozur, G. E.; Proskurovsky, D. I.

2018-01-01

This paper is a review of studies on the generation of low-energy high-current electron beams in electron guns with a plasma anode and an explosive-emission cathode. The problems related to the initiation of explosive electron emission under plasma and the formation and transport of high-current electron beams in plasma-filled systems are discussed consecutively. Considerable attention is given to the nonstationary effects that occur in the space charge layers of plasma. Emphasis is also placed on the problem of providing a uniform energy density distribution over the beam cross section, which is of critical importance in using electron beams of this type for surface treatment of materials. Examples of facilities based on low-energy high-current electron beam sources are presented and their applications in materials science and practice are discussed.

Explosively driven air blast in a conical shock tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, Joel B., E-mail: joel.b.stewart2.civ@mail.mil; Pecora, Collin, E-mail: collin.r.pecora.civ@mail.mil

2015-03-15

Explosively driven shock tubes present challenges in terms of safety concerns and expensive upkeep of test facilities but provide more realistic approximations to the air blast resulting from free-field detonations than those provided by gas-driven shock tubes. Likewise, the geometry of conical shock tubes can naturally approximate a sector cut from a spherically symmetric blast, leading to a better agreement with the blast profiles of free-field detonations when compared to those provided by shock tubes employing constant cross sections. The work presented in this article documents the design, fabrication, and testing of an explosively driven conical shock tube whose goalmore » was to closely replicate the blast profile seen from a larger, free-field detonation. By constraining the blast through a finite area, large blasts (which can add significant damage and safety constraints) can be simulated using smaller explosive charges. The experimental data presented herein show that a close approximation to the free-field air blast profile due to a 1.5 lb charge of C4 at 76 in. can be achieved by using a 0.032 lb charge in a 76-in.-long conical shock tube (which translates to an amplification factor of nearly 50). Modeling and simulation tools were used extensively in designing this shock tube to minimize expensive fabrication costs.« less

Surface Instabilities From Buried Explosives

DTIC Science & Technology

2009-07-21

interface between soil and air during buried explosions. The purpose of understanding this instability is to determine its effect on local vehicle loading...Except when the target is on the surface, e.g., a tank track, the most important loading mechanism from a buried charge is the impact of soil propelled...rising soil and the air. This unstable 15. SUBJECT TERMS Buried Explosions, Richtmyer-Meshkov Instability, Target Loading, Jetting, 16 SECURITY

Smokeless Propellants as Vehicle Borne IED Main Charges: An Initial Threat Assessment

DTIC Science & Technology

2008-01-01

uci: • danger clasa : (B) critical detonation height I 45 - 65 em. detonation danger , during fillin. material in mixing trough, in barrels as a in...Appendix A Examples ofMorphology Appendix B ATF List of Explosives Materials Appendix C Cabella Web Page Appendix D ATF Intelligence Report on Explosives...available for exploitation by violent extremist organizations and individuals. Discussion: Conventional explosive materials remain the most probable

Invited Article: Quantitative imaging of explosions with high-speed cameras

DOE PAGES

McNesby, Kevin L.; Homan, Barrie E.; Benjamin, Richard A.; ...

2016-05-31

Here, the techniques presented in this paper allow for mapping of temperature, pressure, chemical species, and energy deposition during and following detonations of explosives, using high speed cameras as the main diagnostic tool. Additionally, this work provides measurement in the explosive near to far-field (0-500 charge diameters) of surface temperatures, peak air-shock pressures, some chemical species signatures, shock energy deposition, and air shock formation.

High Power Microwaves for Defense and Accelerator Applications

DTIC Science & Technology

1990-06-11

pulsed power machines are typically made for laboratory simulation of charged particle and radiation spectra of nuclear explosions . Early on, it was...cathode and then explosive 10 ionization. After the first few nanoseconds, the electron emission is from a plasma produced at the cathode. Typically the...Virtually nothing is needed except an electron beam source. This power and simplicity makes vircators particularly interesting for single shot or explosively

SN 2016esw: a luminous Type II supernova observed within the first day after the explosion

NASA Astrophysics Data System (ADS)

de Jaeger, Thomas; Galbany, Lluis; Gutiérrez, Claudia P.; Filippenko, Alexei V.; Zheng, WeiKang; Brink, Thomas G.; Foley, Ryan J.; Sánchez, Sebastian F.; Channa, Sanyum; de Kouchkovsky, Maxime; Halevi, Goni; Kilpatrick, Charles D.; Kumar, Sahana; Molloy, Jeffrey; Pan, Yen-Chen; Ross, Timothy W.; Shivvers, Isaac; Siebert, Matthew R.; Stahl, Benjamin; Stegman, Samantha; Yunus, Sameen

2018-05-01

We present photometry, spectroscopy, and host-galaxy integral-field spectroscopy of the Type II supernova (SN) 2016esw in CGCG 229-009 from the first day after the explosion up to 120 days. Its light-curve shape is similar to that of a typical SN II; however, SN 2016esw is near the high-luminosity end of the SN II distribution, with a peak of M^maxV=-18.36 mag. The V-band light curve exhibits a long recombination phase for a SN II (similar to the long-lived plateau of SN 2004et). Considering the well-known relation between the luminosity and the plateau decline rate, SN 2016esw should have a V-band slope of ˜2.10 mag (100 days)-1; however, SN 2016esw has a substantially flatter plateau with a slope of 1.01 ± 0.26 mag (100 days)-1, perhaps indicating that interacting Type II supernovae are not useful for cosmology. At 19.5 days post-explosion, the spectrum presents a boxy Hα emission line with flat absorption profiles, suggesting interaction between the ejecta and circumstellar matter. Finally, based on the spectral properties, SN 2016esw shows similarities with the luminous and interacting SN 2007pk at early epochs, particularly in terms of observable line features and their evolution.

Numerical simulation study on thermal response of PBX 9501 to low velocity impact

NASA Astrophysics Data System (ADS)

Lou, Jianfeng; Zhou, Tingting; Zhang, Yangeng; Zhang, Xiaoli

2017-01-01

Impact sensitivity of solid high explosives, an important index in evaluating the safety and performance of explosives, is an important concern in handling, storage, and shipping procedures. It is a great threat for either bare dynamite or shell charge when subjected to low velocity impact involved in traffic accidents or charge piece drops. The Steven test is an effective tool to study the relative sensitivity of various explosives. In this paper, we built the numerical simulation method involving mechanical, thermo and chemical properties of Steven test based on the thermo-mechanical coupled material model. In the model, the stress-strain relationship is described by dynamic plasticity model, the thermal effect of the explosive induced by impact is depicted by isotropic thermal material model, the chemical reaction of explosives is described by Arrhenius reaction rate law, and the effects of heating and melting on mechanical properties and thermal properties of materials are also taken into account. Specific to the standard Steven test, the thermal and mechanical response rules of PBX 9501 at various impact velocities were numerically analyzed, and the threshold velocity of explosive initiation was obtained, which is in good agreement with experimental results. In addition, the effect of confine condition of test device to the threshold velocity was explored.

Measurement of Front Curvature and Detonation Velocity for a Nonideal Heterogeneous Explosive in Axisymmetric and Two-Dimensional Geometries

NASA Astrophysics Data System (ADS)

Higgins, Andrew

2009-06-01

Detonation in a heterogeneous explosive with a relatively sparse concentration of reaction centers (``hot spots'') is investigated experimentally. The explosive system considered is nitromethane gelled with PMMA and with glass microballoons (GMB's) in suspension. The detonation velocity is measured as a function of the characteristic charge dimension (diameter or thickness) in both axisymmetric and two-dimensional planar geometries. The use of a unique, annular charge geometry (with the diameter of the annulus much greater than the annular gap thickness) permits quasi-two-dimensional detonations to be observed without undesirable lateral rarefactions that result from a finite aspect ratio. The detonation front curvature is also measured directly using an electronic streak camera. The results confirm the prior findings of Gois et al. (1996) which showed that, for a low concentration of GMB's, detonation propagation does not exhibit the expected 2:1 scaling from axisymmetric to planar geometries. This reinforces the idea that detonation in highly nonideal explosives is not governed exclusively by front curvature.

Thermodynamic Model of Afterburning in Explosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhl, A L; Howard, M; Fried, L

2003-04-23

Thermodynamic states encountered during afterburning of explosion products gases in air were analyzed with the Cheetah code. Results are displayed in the form of Le Chatelier diagrams: the locus of states of specific internal energy versus temperature, for six different condensed explosives charges. Accuracy of the results was confirmed by comparing the fuel and products curves with the heats of detonation and combustion, and species composition as measured in bomb calorimeter experiments. Results were fit with analytic functions u = f ( T ) suitable for specifying the thermodynamic properties required for gas-dynamic models of afterburning in explosions.

Synthesis of TiCx Powder via the Underwater Explosion of an Explosive

NASA Astrophysics Data System (ADS)

Tanaka, Shigeru; Bataev, Ivan; Hamashima, Hideki; Tsurui, Akihiko; Hokamoto, Kazuyuki

2018-05-01

In this study, a novel approach to the explosive synthesis of titanium carbide (TiC) is discussed. Nonstoichiometric TiCx powder was produced via the underwater explosion of a Ti powder encapsulated within a spherical explosive charge. The explosion process, bubble formation, and synthesis process were visualized using high-speed camera imaging. It was concluded that synthesis occurred within the detonation gas during the first expansion/contraction cycle of the bubble, which was accompanied by a strong emission of light. The recovered powders were studied using scanning electron microscopy and X-ray diffraction. Submicron particles were generated during the explosion. An increase in the carbon content of the starting powder resulted in an increase in the carbon content of the final product. No oxide byproducts were observed within the recovered powders.

Turbulent combustion in aluminum-air clouds for different scale explosion fields

NASA Astrophysics Data System (ADS)

Kuhl, Allen L.; Balakrishnan, Kaushik; Bell, John B.; Beckner, Vincent E.

2017-01-01

This paper explores "scaling issues" associated with Al particle combustion in explosions. The basic idea is the following: in this non-premixed combustion system, the global burning rate is controlled by rate of turbulent mixing of fuel (Al particles) with air. From similarity considerations, the turbulent mixing rates should scale with the explosion length and time scales. However, the induction time for ignition of Al particles depends on an Arrhenius function, which is independent of the explosion length and time. To study this, we have performed numerical simulations of turbulent combustion in unconfined Al-SDF (shock-dispersed-fuel) explosion fields at different scales. Three different charge masses were assumed: 1-g, 1-kg and 1-T Al-powder charges. We found that there are two combustion regimes: an ignition regime—where the burning rate decays as a power-law function of time, and a turbulent combustion regime—where the burning rate decays exponentially with time. This exponential dependence is typical of first order reactions and the more general concept of Life Functions that control the dynamics of evolutionary systems. Details of the combustion model are described. Results, including mean and rms profiles in combustion cloud and fuel consumption histories, are presented.

Guidance on the Assessment and Development of Insensitive Munitions (MURAT)

DTIC Science & Technology

2006-05-01

theoretical modelling . For this reason it is the best understood of all the areas on the flowchart. If the charge is already shocked by a previous impact...the initiation of heterogeneous high explosives due to shock waves are finite rate chemical reactions involved in the conversion of solid explosive ... explosive , increasing the chance of shock initiation (N26) Such an impact would have to take account of case material ahead of the fragment

Swedish Defence Research Abstracts 82/83-3 (Froe Foersvars Forsknings Referat 82/83-3)

DTIC Science & Technology

1983-12-01

A PROTECTION - ATOMIC A3 Effects of nuclear explosions , and protective measures (I 13) Radioactive fallout from nuclear weapons. A review of airborne...AND WEAPON TECHNOLOGY DI Technology of explosives (119) Boron-containing fuel-rich HTPB propellants. Manufacturing, burning experiments and specific...technology (122) TRYCK. A command procedure for presenting the param.ters of the shock wave •.:’. from detonating high- explosive charges D8 System studies (123

Terminal velocity of liquids and granular materials dispersed by a high explosive

NASA Astrophysics Data System (ADS)

Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

2018-05-01

The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass ( M/ C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/ C ratio, with larger M/ C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

Terminal velocity of liquids and granular materials dispersed by a high explosive

NASA Astrophysics Data System (ADS)

Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

2018-04-01

The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass (M/C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/C ratio, with larger M/C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

Organic nanoparticles for photovoltaic and sensing applications

NASA Astrophysics Data System (ADS)

Venkatraman, B. Harihara

2011-12-01

Can organic semiconducting nanoparticles be used as building blocks for fabricating electronic devices? The first half of this dissertation focuses on addressing this question and the associated research challenges for attaining morphological control pertaining to organic photovoltaic devices by nanoparticle assembly. Conjugated polymer nanoparticles were synthesized using miniemulsion technique and their optical, charge transfer and charge transport properties were studied. Some degree of control in polymer chain packing within the nanoparticle was also demonstrated. The optical, charge transfer and charge transport properties of these nanoparticles were found to be similar to that of parent conjugated polymer irrespective of the surface charge. From the initial photovoltaic measurements, it is shown that these nanoparticles are potential candidates for fabricating future photovoltaic devices. The second half of this dissertation is focused on developing a novel and viable strategy for sensing aqueous based nitroaromatic compounds. Nitroaromatic compounds are commonly used as explosives and possess serious health hazards. Thiophene-based conjugated polymer nanoparticles were synthesized and were shown to effectively detect aqueous based nitroaromatic explosives.

Arbitrarily shaped high-coherence electron bunches from cold atoms

NASA Astrophysics Data System (ADS)

McCulloch, A. J.; Sheludko, D. V.; Saliba, S. D.; Bell, S. C.; Junker, M.; Nugent, K. A.; Scholten, R. E.

2011-10-01

Ultrafast electron diffractive imaging of nanoscale objects such as biological molecules and defects in solid-state devices provides crucial information on structure and dynamic processes: for example, determination of the form and function of membrane proteins, vital for many key goals in modern biological science, including rational drug design. High brightness and high coherence are required to achieve the necessary spatial and temporal resolution, but have been limited by the thermal nature of conventional electron sources and by divergence due to repulsive interactions between the electrons, known as the Coulomb explosion. It has been shown that, if the electrons are shaped into ellipsoidal bunches with uniform density, the Coulomb explosion can be reversed using conventional optics, to deliver the maximum possible brightness at the target. Here we demonstrate arbitrary and real-time control of the shape of cold electron bunches extracted from laser-cooled atoms. The ability to dynamically shape the electron source itself and to observe this shape in the propagated electron bunch provides a remarkable experimental demonstration of the intrinsically high spatial coherence of a cold-atom electron source, and the potential for alleviation of electron-source brightness limitations due to Coulomb explosion.

Quantification of vesicle characteristics in some diatreme-filling deposits, and the explosivity levels of magma-water interactions within diatremes

NASA Astrophysics Data System (ADS)

Ross, Pierre-Simon; White, James D. L.

2012-11-01

Vesicles within juvenile fragments in mafic pyroclastic deposits contain important information about the state of the magma at the time of fragmentation. There have been few vesicle studies of juvenile pyroclasts from mafic phreatomagmatic deposits, however, and none we can find from maar-diatreme volcanoes. In this paper we document the vesicularity and vesicle-population characteristics of juvenile fragments sampled from non-bedded lithified deposits of the Coombs Hills diatreme complex, part of the Ferrar large igneous province, Antarctica. The diatreme-filling pyroclastic deposits, dominated by lapilli tuffs and tuff breccias, contain typically abundant lithic clasts derived mostly from the enclosing sedimentary sequence, and several types of juvenile clasts ranging from blocky to fluidal or "raggy". In the samples measured, 77-80% of the juvenile pyroclasts ranging in size from 0.5 mm to fine lapilli is in the 'non-vesicular' to 'incipiently vesicular' range (< 20% vesicles). Such low vesicularities are expected for pyroclasts from maar-diatreme volcanoes where fragmentation takes place at depth in the diatreme or root zone due to magma-water interaction. A few juvenile clasts, however, are more vesicular, and seven of these were chosen and sectioned for 2D analysis of vesicle shapes and orientation, vesicle number densities (Nv), and vesicle volume distributions. The shapes of the vesicles in the studied sections are mostly elliptical (sometimes polylobate), with mean aspect ratios ranging between 0.67 and 0.72. Circular statistics are used to test for trends in the vesicle long-axis orientation data; non-uniformity of orientations is found in most cases, but the trends are weak. Vesicle volume distributions are often bimodal due to variable coalescence. Total Nv values range from 1.0 × 102 to 5.7 × 103 mm- 3; taking the effects of bubble coalescence into account, these values are similar to those found in pyroclasts from other phreatomagmatic volcanoes, although they also overlap partly with those seen in fire fountain deposits and some basaltic Plinian eruptions. Fluidal- or rag-shaped juvenile clasts, some circular vesicles, and the lack of microlites all suggest that the Coombs Hills magma had a relatively low viscosity prior to fragmentation, despite the basaltic andesite composition. This low viscosity allowed parts of the magma to be fragmented in a non-brittle fashion during phreatomagmatic explosions and to form fluidal clasts. Phreatomagmatic explosions in diatremes can therefore produce diverse types of juvenile clasts simultaneously, and the proportions of each will depend on the explosivity of the magma-water (slurry) interaction and other factors. Recycling of fragments is also thought to be an important factor in generating mixtures of different types of juvenile fragments in diatremes.

A Parametric Approach to Shape Field-Relevant Blast Wave Profiles in Compressed-Gas-Driven Shock Tube

PubMed Central

Sundaramurthy, Aravind; Chandra, Namas

2014-01-01

Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse and called herein as shock-blast wave parameters (SWPs). These parameters in turn are uniquely determined by the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (1–3), the profile not only determines the survival of the subjects (e.g., animals) but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field-relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. Forty experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68–1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The effects SAPs have on the resulting shock-blast profiles are shown. Also, the shock-blast profiles of a TNT explosion from ConWep software is compared with the profiles obtained from the shock tube. To conclude, our experimental results demonstrate that a compressed-gas shock tube when designed and operated carefully can replicate the blast time profiles of field explosions accurately. Such a faithful replication is an essential first step when studying the effects of blast induced neurotrauma using animal models. PMID:25520701

KSC-99pp1239

NASA Image and Video Library

1999-10-14

KENNEDY SPACE CENTER, FLA. — Two 34-year-old towers on Launch Complex 41, Cape Canaveral Air Station, fall to the ground amid the black smoke from explosives set to topple them. Weighing two million pounds, the umbilical tower (left) was approximately 200 feet high. The taller 300-foot Mobile Service Tower (right) weighs five million pounds. About 200 pounds of linear-shaped charges were used to topple the towers so that the materials can be recycled. Adjacent to the towers are lightning protection structures, which will remain on the site. The towers are being demolished to make room for Lockheed Martin's 14-acre Vehicle Integration Facility (VIF), under construction. The implosion and removal of the tower debris is expected to be completed in two months. The VIF will be used for Lockheed Martin's Atlas V Launch System.

KSC-99pp1238

NASA Image and Video Library

1999-10-14

KENNEDY SPACE CENTER, FLA. — Two 34-year-old towers on Launch Complex 41, Cape Canaveral Air Station, lie on the ground amid the black smoke from explosives set to topple them. Weighing two million pounds, the umbilical tower (left) was approximately 200 feet high. The taller 300-foot Mobile Service Tower (right) weighs five million pounds. About 200 pounds of linear-shaped charges were used to topple the towers so that the materials can be recycled. Adjacent to the towers are lightning protection structures, which will remain on the site. The towers are being demolished to make room for Lockheed Martin's 14-acre Vehicle Integration Facility (VIF), under construction. The implosion and removal of the tower debris is expected to be completed in two months. The VIF will be used for Lockheed Martin's Atlas V Launch System.

Separating large microscale particles by exploiting charge differences with dielectrophoresis.

PubMed

Polniak, Danielle V; Goodrich, Eric; Hill, Nicole; Lapizco-Encinas, Blanca H

2018-04-13

Dielectrophoresis (DEP), the migration of particles due to polarization effects under the influence of a nonuniform electric field, was employed for characterizing the behavior and achieving the separation of larger (diameter >5 μm) microparticles by exploiting differences in electrical charge. Usually, electrophoresis (EP) is the method of choice for separating particles based on differences in electrical charge; however, larger particles, which have low electrophoretic mobilities, cannot be easily separated with EP-based techniques. This study presents an alternative for the characterization, assessment, and separation of larger microparticles, where charge differences are exploited with DEP instead of EP. Polystyrene microparticles with sizes varying from 5 to 10 μm were characterized employing microdevices for insulator-based dielectrophoresis (iDEP). Particles within an iDEP microchannel were exposed simultaneously to DEP, EP, and electroosmotic (EO) forces. The electrokinetic behavior of four distinct types of microparticles was carefully characterized by means of velocimetry and dielectrophoretic capture assessments. As a final step, a dielectropherogram separation of two distinct types of 10 μm particles was devised by first characterizing the particles and then performing the separation. The two types of 10 μm particles were eluted from the iDEP device as two separate peaks of enriched particles in less than 80 s. It was demonstrated that particles with the same size, shape, surface functionalization, and made from the same bulk material can be separated with iDEP by exploiting slight differences in the magnitude of particle charge. The results from this study open the possibility for iDEP to be used as a technique for the assessment and separation of biological cells that have very similar characteristics (shape, size, similar make-up), but slight variance in surface electrical charge. Copyright © 2018 Elsevier B.V. All rights reserved.

Safety hazards associated with the charging of lithium/sulfur dioxide cells

NASA Technical Reports Server (NTRS)

Frank, H.; Halpert, G.; Lawson, D. D.; Barnes, J. A.; Bis, R. F.

1986-01-01

A continuing research program to assess the responses of spirally wound, lithium/sulfur dioxide cells to charging as functions of charging current, temperature, and cell condition prior to charging is described. Partially discharged cells that are charged at currents greater than one ampere explode with the time to explosion inversely proportional to the charging current. Cells charged at currents of less than one ampere may fail in one of several modes. The data allows an empirical prediction of when certain cells will fail given a constant charging current.

Non-focusing active warhead

DOEpatents

Hornig, H.C.

1998-12-22

A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal is disclosed. When the high explosive is detonated, the reactive metal is dispersed and reacts with the air, which significantly increases the explosive yield of the warhead. The active warhead produces therefore much higher blast effects with significantly reduced weight compared to conventional munitions. The warhead is highly effective against such targets as aircraft which typically have thin fuselages, for example. The explosiveness of this warhead can be enhanced further by elevating the temperature and therefore the reactivity of the reactive metal before or during the explosion. New methods of enhancing the reactivity of the metal are also taught. 4 figs.

Non-focusing active warhead

DOEpatents

Hornig, Howard C.

1998-01-01

A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal. When the high explosive is detonated, the reactive metal is dispersed and reacts with the air, which significantly increases the explosive yield of the warhead. The active warhead produces therefore much higher blast effects with significantly reduced weight compared to conventional munitions. The warhead is highly effective against such targets as aircraft which typically have thin fuselages, for example. The explosiveness of this warhead can be enhanced further by elevating the temperature and therefore the reactivity of the reactive metal before or during the explosion. New methods of enhancing the reactivity of the metal are also taught.

Comparison of Post-detonation Combustion in Explosives Incorporating Aluminum Nanoparticles: Influence of the Passivation Layer (Postprint)

DTIC Science & Technology

2013-01-31

meters away from the explosive charge. The collection optic were aligned to view the center of each charge through a BK7 glass view- port. The...Basler Sprint ) with a data collection rate of 1–70 kHz. The resolution and usable spectral range of the spectrograph were 1.2 nm and 380–720 nm...RDX 20 wt. % AlOA in RDX 20 wt. % AlFA in RDX 0 … … … 15 … 4000 ( 400 ) … 30 3900 (200) 4500 (500) 3200 (300) 45 3600 (300) 򓇨 3400 (500) 044907-3

High-speed velocity measurements on an EFI-system

NASA Astrophysics Data System (ADS)

Prinse, W. C.; van't Hof, P. G.; Cheng, L. K.; Scholtes, J. H. G.

2007-01-01

For the development of an Exploding Foil Initiator for Insensitive Munitions applications the following topics are of interest: the electrical circuit, the exploding foil, the velocity of the flyer, the driver explosive, the secondary flyer and the acceptor explosive. Several parameters of the EFI have influences on the velocity of the flyer. To investigate these parameters a Fabry-Perot Velocity Interferometer System (F-PVIS) has been used. The light to and from the flyer is transported by a multimode fibre terminated with a GRIN-lens. By this method the velocity of very tiny objects (0.1 mm), can be measured. The velocity of flyer can be recorded with nanosecond resolution, depending on the Fabry-Perot etalon and the streak camera. With this equipment the influence of the dimensions of the exploding foil and the flyer on the velocity and the acceleration of the flyer are investigated. Also the integrity of the flyer during flight can be analyzed. To characterize the explosive material, to be used as driver explosive in EFI's, the initiation behaviour of the explosive has been investigated by taking pictures of the explosion with a high speed framing and streak camera. From these pictures the initiation distance and the detonation behaviour of the explosive has been analyzed. Normally, the driver explosive initiates the acceptor explosive (booster) by direct contact. This booster explosive is embedded in the main charge of the munitions. The combination of initiator, booster explosive and main charge explosive is called the detonation train. In this research the possibility of initiation of the booster by an intermediate flyer is investigated. This secondary flyer can be made of different materials, like aluminium, steel and polyester with different sizes. With the aid of the F-PVIS the acceleration of the secondary flyer is investigated. This reveals the influence of the thickness and density of the flyer on the acceleration and final velocity. Under certain circumstances the flyer breaks up in several parts and several velocities at the same time have been recorded. Several flyer materials and dimensions exist that are able to initiate very insensitive explosives like TATB.

Flame Speeds and Energy Considerations for Explosions in a Spherical Bomb

NASA Technical Reports Server (NTRS)

Fiock, Ernest F; Marvin, Charles F , Jr; Caldwell, Frank R; Roeder, Carl H

1940-01-01

Simultaneous measurements were made of the speed of flame and the rise in pressure during explosions of mixtures of carbon monoxide, normal heptane, iso-octane, and benzene in a 10-inch spherical bomb with central ignition. From these records, fundamental properties of the explosive mixtures, which are independent of the apparatus, were computed. The transformation velocity, or speed at which flame advances into and transforms the explosive mixture, increases with both the temperature and the pressure of the unburned gas. The rise in pressure was correlated with the mass of charge inflamed to show the course of the energy developed.

Common Low-cost IM Explosive Program. Development of Next Generation Insensitive Munitions: A Success Story

DTIC Science & Technology

2011-11-30

fuze separating from the shell body preventing high order detonations thus saving the lives of the Soldiers. Unit’s SPC Alan Ng  with his father Peter...Sensitive If not fully compliant, must show improvement over Baseline explosive Affordable Artillery Cost Drivers = Steel Body Material & Explosive Fill...Mortar Cost Drivers = Steel Body Material, Fuze & Propelling Charges Producible within the National Technology and Industrial Base Infrastructure

Review of potential impacts to sea turtles from underwater explosive removal of offshore structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viada, Stephen T.; Hammer, Richard M.; Racca, Roberto

2008-05-15

The purpose of this study was to collect and synthesize existing information relevant to the explosive removal of offshore structures (EROS) in aquatic environments. Data sources were organized and summarized by topic - explosive removal methods, physics of underwater explosions, sea turtle resources, documented impacts to sea turtles, and mitigation of effects. Information was gathered via electronic database searches and literature source review. Bulk explosive charges are the most commonly used technique in EROS. While the physical principles of underwater detonations and the propagation of pressure and acoustic waves are well understood, there are significant gaps in the application ofmore » this knowledge. Impacts to sea turtles from explosive removal operations may range from non-injurious effects (e.g. acoustic annoyance; mild tactile detection or physical discomfort) to varying levels of injury (i.e. non-lethal and lethal injuries). Very little information exists regarding the impacts of underwater explosions on sea turtles. Effects of explosions on turtles often must be inferred from documented effects to other vertebrates with lungs or other gas-containing organs, such as mammals and most fishes. However, a cautious approach should be used when determining impacts to sea turtles based on extrapolations from other vertebrates. The discovery of beached sea turtles and bottlenose dolphins following an explosive platform removal event in 1986 prompted the initiation of formal consultation between the U.S. Department of the Interior, Minerals Management Service (MMS) and the National Marine Fisheries Service (NMFS), authorized through the Endangered Species Act Section 7, to determine a mechanism to minimize potential impacts to listed species. The initial consultation resulted in a requirement for oil and gas companies to obtain a permit (through separate consultations on a case-by-case basis) prior to using explosives in Federal waters. Because many offshore structure removal operations are similar, a 'generic' Incidental Take Statement was established by the NMFS that describes requirements to protect sea turtles when an operator's individual charge weights did not exceed 50 lb (23 kg). Requirements associated with the Incidental Take Permit were revised in 2003 and 2006 to accommodate advances in explosive charge technologies, removals of structures in deeper waters, and adequate protection of deep water marine mammal species in Gulf of Mexico waters. Generally, these requirements include pre- and post-detonation visual monitoring using standard surface and aerial survey methods for sea turtles and marine mammals, and, in some scenarios, passive acoustic survey methods for marine mammals within a specified radius from an offshore structure. The survey program has been successful in mitigating impacts to sea turtles associated with EROS. However, even with these protective measures in place, there have been observations of sea turtles affected by explosive platform removals.« less

Subscale testing of prompt agent defeat formulations

NASA Astrophysics Data System (ADS)

Knott, A.; Stamatis, D.; Svingala, F.; Lightstone, J.; Miller, K.; Bensman, M.; Bohmke, M.

2017-01-01

There is a need to improve the current bioagent defeat systems with formulations that produce lower peak pressure and impulse, sustained high temperatures, and release of biocidal species for prompt defeat applications. In this work, explosive charge configurations similar to fuel-air explosives were detonated in a semi-enclosed chamber configuration. Binder type and fuel-to-oxidizer ratios were varied to observe the effects on combustion performance. Thermocouple measurements and high-speed video were used to monitor the combustion of the dispersed formulation. The down-selected formulations were then tested in a sub-scale vented agent defeat system developed to evaluate performance of formulations against aerosolized Bacillus thuringiensis (Bt) spores. Diagnostics including thermocouples and piezoelectric pressure gauges were utilized to characterize the detonation event. Biological sampling with surface coupons, liquid impingement, and filters of the post detonation environment were utilized to determine spore survivability and to rank the relative effectiveness of each formulation.

Anisotropic Coulomb Explosion of CO Ligands in Group 6 Metal Hexacarbonyls: Cr(CO)6, Mo(CO)6, W(CO)6.

PubMed

Tanaka, Hiroki; Nakashima, Nobuaki; Yatsuhashi, Tomoyuki

2016-09-08

Multiple ionization and subsequent Coulomb explosion have been studied for many organic molecules and their clusters; however, the metal complexes, particularly the large Coulombic interactions expected between a metal and its ligands, have not yet been explored. In this study, the angular distribution of CO(+), oxygen, and carbon ions ejected from metal hexacarbonyls (M(CO)6, M: Cr, Mo, W) having Oh symmetry by Coulomb explosion in femtosecond laser fields (>1 × 10(14) W cm(-2)) is investigated. The emissions of oxygen ions are well-explained in terms of the geometric alignment along a line inclined 45° relative to the CO-M-CO axis in a M(CO)4 plane. Unlike the explosion behavior of the oxygen ions located on the outer part of the molecule, the explosion behavior of the carbon ions was affected by the laser intensity, kinetic energy, and metal. This finding that the emission trends of carbon sandwiched between oxygen and metal atoms were the opposite of those for oxygen was explained by the obstruction by oxygen, the deformation of structure in bending coordinates, and the strong interaction with charged metal. The anisotropic Coulomb explosion of metal complexes reflecting their structural symmetry and central metal charge is a promising candidate for use in the investigation of large Coulombic interactions at the molecular level.

An Experimental Study of Corner Turning in a Granular Ammonium Nitrate Based Explosive

NASA Astrophysics Data System (ADS)

Sorber, S.; Taylor, P.; Burns, M.

2007-12-01

A novel experimental geometry has been designed to perform controlled studies of corner turning in a "tap density" granular explosive. It enables the study of corner turning and detonation properties with high speed framing camera, piezo probes and ionisation probes. The basic geometry consists of a large diameter PMMA cylinder filled with the granular explosive and is initiated on axis from below by a smaller diameter cylinder of granular explosive or a booster charge. Four experiments were performed on a granular Ammonium Nitrate based non-ideal explosive (NIE). Two experiments were initiated directly with the PE4 booster and two were initiated from a train including a booster charge and a 1″ diameter copper cylinder containing the same NIE. Experimental data from the four experiments was reproducible and the observed detonation and shock waves showed good 2-D symmetry. Detonation phase velocity on the vertical side of the main container was observed and both shock and detonation velocities were observed in the corner turning region along the base of the main container. Analysis of the data shows that the booster-initiated geometries with a higher input shock pressure into the granular explosive gave earlier detonation arrival at the lowest probes on the container side. The corner turning data is compared to a hydrocode calculation using a simple JWL++ reactive burn model.

Explosive cord

NASA Technical Reports Server (NTRS)

1972-01-01

Device, jetcord, is metal-clad linear explosive of sufficient flexibility to allow forming into intricate shapes. Total effect is termed ''cutting'' with jetcord consistently ''cutting'' a target of greater thickness than can be penetrated. Applications include sheet metal working, pipe cutting and fire-fighting.

77 FR 31333 - Taking and Importing Marine Mammals: Taking Marine Mammals Incidental to Navy Training Exercises...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-25

... VACAPES Range Complex, the Navy conducted 14 5-lb charge, 28 10-lb charge, and 3 20-lb charge mine... missile) exercises and 1 AGM-65 (Maverick missile) exercise (MISSIEX); and 13 5' explosive Naval gunfire... (PAM) devices. The monitoring efforts for 2011 were conducted within the mine neutralization exercise...

30 CFR 77.1303 - Explosives, handling and use.

Code of Federal Regulations, 2012 CFR

2012-07-01

... than one shot is to be fired at one time, blasting shall be done electrically or with detonating cord... shots are fired. (f) Explosives shall be kept separated from detonators until charging is started. (g... blunt and squared at one end and made of wood, nonsparking material, or of special plastic acceptable to...

30 CFR 77.1303 - Explosives, handling and use.

Code of Federal Regulations, 2014 CFR

2014-07-01

... than one shot is to be fired at one time, blasting shall be done electrically or with detonating cord... shots are fired. (f) Explosives shall be kept separated from detonators until charging is started. (g... blunt and squared at one end and made of wood, nonsparking material, or of special plastic acceptable to...

30 CFR 77.1303 - Explosives, handling and use.

Code of Federal Regulations, 2013 CFR

2013-07-01

... than one shot is to be fired at one time, blasting shall be done electrically or with detonating cord... shots are fired. (f) Explosives shall be kept separated from detonators until charging is started. (g... blunt and squared at one end and made of wood, nonsparking material, or of special plastic acceptable to...

30 CFR 77.1303 - Explosives, handling and use.

Code of Federal Regulations, 2010 CFR

2010-07-01

... than one shot is to be fired at one time, blasting shall be done electrically or with detonating cord... shots are fired. (f) Explosives shall be kept separated from detonators until charging is started. (g... blunt and squared at one end and made of wood, nonsparking material, or of special plastic acceptable to...

30 CFR 77.1303 - Explosives, handling and use.

Code of Federal Regulations, 2011 CFR

2011-07-01

... than one shot is to be fired at one time, blasting shall be done electrically or with detonating cord... shots are fired. (f) Explosives shall be kept separated from detonators until charging is started. (g... blunt and squared at one end and made of wood, nonsparking material, or of special plastic acceptable to...

30 CFR 75.1501 - Emergency evacuations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... by the mine operator to take charge during mine emergencies involving a fire, explosion, or gas or... prescribed by MSHA's Office of Educational Policy and Development. The course will include topics such as the... there is a mine emergency which presents an imminent danger to miners due to fire or explosion or gas or...

30 CFR 75.1501 - Emergency evacuations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... by the mine operator to take charge during mine emergencies involving a fire, explosion, or gas or... prescribed by MSHA's Office of Educational Policy and Development. The course will include topics such as the... there is a mine emergency which presents an imminent danger to miners due to fire or explosion or gas or...

30 CFR 75.1501 - Emergency evacuations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... by the mine operator to take charge during mine emergencies involving a fire, explosion, or gas or... prescribed by MSHA's Office of Educational Policy and Development. The course will include topics such as the... there is a mine emergency which presents an imminent danger to miners due to fire or explosion or gas or...

30 CFR 75.1501 - Emergency evacuations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... by the mine operator to take charge during mine emergencies involving a fire, explosion, or gas or... prescribed by MSHA's Office of Educational Policy and Development. The course will include topics such as the... there is a mine emergency which presents an imminent danger to miners due to fire or explosion or gas or...

A deep towed explosive source for seismic experiments on the ocean floor

NASA Astrophysics Data System (ADS)

Koelsch, Donald E.; Witzell, Warren E.; Broda, James E.; Wooding, Frank B.; Purdy, G. M.

1986-12-01

A new seismic source for carrying out high resolution measurements of deep ocean crustal structure has been constructed and successfully used in a number of ocean bottom refraction experiments on the Mid Atlantic Ridge near 23° N. The source is towed within 100 m of the ocean floor on a conventional 0.68″ coaxial cable and is capable of firing, upon command from the research vessel, up to 48 individual 2.3 kg explosive charges. The explosive used was commercially available Penta-Erythritol-Tetra Nitrate (PETN) that was activated by 14.9 gm m-1 Primacord and DuPont E-97 electrical detonators. For safety reasons each detonator was fitted with a pressure switch that maintained a short until the source was at depth in excess of approximately 300 m. In addition, a mechanical protector isolated the detonator from the main charge and was only removed by the physical release of the explosive from the source package. These and other safety precautions resulted in several misfires but three experiments were successfully completed during the summer of 1985 at source depths of 3000 4000 m.

East Europe Report, Political, Sociological and Military Affairs

DTIC Science & Technology

1984-12-13

piledriver and make them effective . Currently, we have two assemblies available for constructing emergency bridges under different conditions: the...mainly "classic- type " depth charges shaped as rolls or cylinders. These were either hurled, rather than shot overboard -from plunger-shaped launchers, or...the time the Soviets had nothing effective with which to oppose this Polaris -force. The previously available antisubmarine weapons turned out to be

Chemical analysis of charged Li/SO(sub)2 cells

NASA Technical Reports Server (NTRS)

Subbarao, S.; Lawson, D.; Frank, H.; Halpert, G.; Barnes, J.; Bis, R.

1987-01-01

The initial focus of the program was to confirm that charging can indeed result in explosions and constitute a significant safety problem. Results of this initial effort clearly demonstrated that cells do indeed explode on charge and that charging does indeed constitute a real and severe safety problem. The results of the effort to identify the chemical reactions involved in and responsible for the observed behavior are described.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, D.M.; Jessop, E.S.; Swansiger, R.W.

Cast cure, extrusion cast, and paste extrudable explosives have not been designed for transferring through long tortuous paths or into fine three dimensional shapes. To allow the crystalline explosive to flow a lubricating fluid is required. The energetic liquid ethane trinitrate (TMETN) was used as the lubricant to maximize the explosive energy. TMETN is a liquid nitrate ester which requires stabilization with conventional free radical stabilizers such as 2- nitrodiphenylamine, methyl-nitroanaline, or ethyl centrylite. Since these injection moldable explosives are expected to cure in place, a polyesterurethane binder based on polymeric isocyanate of hexamethylene diisocyanate and polycaprolactone polyols is dissolvedmore » in TMETN. The solubility of the polymer precursors in TMETN also reduces the energetic liquids sensitivity. The latent cure catalyst Dabco T-131 was used to minimize shrinkage associated with thermal expansion, reduce cost associated with oven cures, to give 4-6 hour potlife and overnight cure to handling strength. The product RX-08-HD is a new, low-viscosity, injection moldable explosive that can be extruded into complex, void-free shapes. Combined with appropriate design and other aspects of weaponization, RX-08-HD has produced outstanding results.« less

Type Ibn Supernovae Show Photometric Homogeneity and Spectral Diversity at Maximum Light

DOE PAGES

Hosseinzadeh, Griffin; Arcavi, Iair; Valenti, Stefano; ...

2017-02-16

Type Ibn supernovae (SNe) are a small yet intriguing class of explosions whose spectra are characterized by low-velocity helium emission lines with little to no evidence for hydrogen. The prevailing theory has been that these are the core-collapse explosions of very massive stars embedded in helium-rich circumstellar material (CSM). We report optical observations of six new SNe Ibn: PTF11rfh, PTF12ldy, iPTF14aki, iPTF15ul, SN 2015G, and iPTF15akq. This brings the sample size of such objects in the literature to 22. We also report new data, including a near-infrared spectrum, on the Type Ibn SN 2015U. In order to characterize the classmore » as a whole, we analyze the photometric and spectroscopic properties of the full Type Ibn sample. Here, we find that, despite the expectation that CSM interaction would generate a heterogeneous set of light curves, as seen in SNe IIn, most Type Ibn light curves are quite similar in shape, declining at rates around 0.1 mag day -1 during the first month after maximum light, with a few significant exceptions. Early spectra of SNe Ibn come in at least two varieties, one that shows narrow P Cygni lines and another dominated by broader emission lines, both around maximum light, which may be an indication of differences in the state of the progenitor system at the time of explosion. Alternatively, the spectral diversity could arise from viewing-angle effects or merely from a lack of early spectroscopic coverage. Finally, together, the relative light curve homogeneity and narrow spectral features suggest that the CSM consists of a spatially confined shell of helium surrounded by a less dense extended wind.« less

Type Ibn Supernovae Show Photometric Homogeneity and Spectral Diversity at Maximum Light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosseinzadeh, Griffin; Arcavi, Iair; McCully, Curtis

2017-02-20

Type Ibn supernovae (SNe) are a small yet intriguing class of explosions whose spectra are characterized by low-velocity helium emission lines with little to no evidence for hydrogen. The prevailing theory has been that these are the core-collapse explosions of very massive stars embedded in helium-rich circumstellar material (CSM). We report optical observations of six new SNe Ibn: PTF11rfh, PTF12ldy, iPTF14aki, iPTF15ul, SN 2015G, and iPTF15akq. This brings the sample size of such objects in the literature to 22. We also report new data, including a near-infrared spectrum, on the Type Ibn SN 2015U. In order to characterize the classmore » as a whole, we analyze the photometric and spectroscopic properties of the full Type Ibn sample. We find that, despite the expectation that CSM interaction would generate a heterogeneous set of light curves, as seen in SNe IIn, most Type Ibn light curves are quite similar in shape, declining at rates around 0.1 mag day{sup −1} during the first month after maximum light, with a few significant exceptions. Early spectra of SNe Ibn come in at least two varieties, one that shows narrow P Cygni lines and another dominated by broader emission lines, both around maximum light, which may be an indication of differences in the state of the progenitor system at the time of explosion. Alternatively, the spectral diversity could arise from viewing-angle effects or merely from a lack of early spectroscopic coverage. Together, the relative light curve homogeneity and narrow spectral features suggest that the CSM consists of a spatially confined shell of helium surrounded by a less dense extended wind.« less

Explosive fluid transmitted shock method for mining deeply buried coal

DOEpatents

Archibald, Paul B.

1976-06-22

A method for recovering coal from deeply buried deposits comprising drilling a hole down into a coal seam, filling the hole with water, and periodically detonating an explosive charge at the bottom of the water-filled hole. The water transmits the explosive shock wave to the face of the coal seam, thereby fracturing and dislodging the coal. The resulting suspension of loose coal in water is then pumped to the surface where the coal is recovered and the water is recycled to the mining operation.

Wavelength-Dependence on the Initiation of Iron-Based Photoactive Explosives

NASA Astrophysics Data System (ADS)

Brown, Kathryn; Myers, Thomas; Clarke, Steven

2017-06-01

Photoactive explosives show promise to be relatively insensitive to impact and friction compared to PETN and other detonator materials, but can be more easily initiated with laser light. Metal-ligand charge transfer (MLCT) complexes have been shown to have tunable explosive properties and absorption profiles, making them strong candidates for laser detonator material. Here, we discuss the synthesis and characterization of several iron-based MLCT complexes, as well as results from recent experiments on their sensitivity to initiation from different wavelengths of laser light.

Explosive Bolt Dual-Initiated from One Side

NASA Technical Reports Server (NTRS)

Snow, Eric

2011-01-01

An explosive bolt has been developed that has a one-sided dual initiation train all the way down to the pyro charge for high reliability, while still allowing the other side of the bolt to remain in place after actuation to act as a thermal seal in an extremely high-temperature environment. This lightweight separation device separates at a single fracture plane, and has as much redundancy/reliability as possible. The initiation train comes into the explosive bolt from one side.

Translation from Russian to English the Book Blast Effects Caused by Explosions Authored by B. Gelfand and M. Silnikov

DTIC Science & Technology

2004-04-01

ingredients were freely b ought in the popular shops of chemicals. The following facts can serve as the evidence of wide use of mine -explosive...workshop rooms etc. The HE charges weight restrictions developed for conducting of blasting operations in open-cast mines and testing areas, are...Russian) 8. Silnikov M.V., Serdtsev N.I., Nelezin P.V. On the prospects of methods of explosion localization for the increase of safety of mine

User’s Guide and History of ANFO (Ammonium Nitrate/Fuel Oil) as a Nuclear Weapons Effect Simulation Explosive

DTIC Science & Technology

1983-03-31

SHOCK SIMULATION 1659 - Amonium nitrate first prepared by Glauber 1867 - Swedish patent granted to Ohlsson and Norrbein for use of ammonium nitrate ...neceessay aqd identify by block number) Ammonium Nitrate -Fuel Oil Aiiblast - . ANFO . Craters High Explosives Explosive Charge Construction * Nuclear...utilizatilon of ANFO for future W FJOAMw. 1473- EDIT00 or INOW ,Sois 0"LTZ"" DO t 473 UNCLASSIFIED SECUM"TY CLASSIFfCATIOl# OF THIS PAGEI(Whonf D Ia LI L

Simulating the blast wave from detonation of a charge using a balloon of compressed air

NASA Astrophysics Data System (ADS)

Blanc, L.; Santana Herrera, S.; Hanus, J. L.

2018-07-01

This paper investigates a simple numerical method, based on the release of a pressurized spherical air volume, to predict or reproduce the main characteristics of the blast environment from the detonation of solid or gaseous charges. This approach aims to give an alternative to the use of a steady-state detonation model and a Jones-Wilkins-Lee equation of state to describe the expansion of the detonation products, especially when the explosive parameters are unknown and a TNT equivalent is used. The validity of the proposed approach is assessed through the comparison of predicted overpressure and impulse at different distances from the explosion with that of TNT and stoichiometric propane-oxygen explosions. It is also shown that, for gaseous detonations, a better agreement is obtained with the rationally optimized compressed balloon than with the use of a Jones-Wilkins-Lee model and a TNT equivalent mass.

Simulating the blast wave from detonation of a charge using a balloon of compressed air

NASA Astrophysics Data System (ADS)

Blanc, L.; Santana Herrera, S.; Hanus, J. L.

2017-11-01

This paper investigates a simple numerical method, based on the release of a pressurized spherical air volume, to predict or reproduce the main characteristics of the blast environment from the detonation of solid or gaseous charges. This approach aims to give an alternative to the use of a steady-state detonation model and a Jones-Wilkins-Lee equation of state to describe the expansion of the detonation products, especially when the explosive parameters are unknown and a TNT equivalent is used. The validity of the proposed approach is assessed through the comparison of predicted overpressure and impulse at different distances from the explosion with that of TNT and stoichiometric propane-oxygen explosions. It is also shown that, for gaseous detonations, a better agreement is obtained with the rationally optimized compressed balloon than with the use of a Jones-Wilkins-Lee model and a TNT equivalent mass.

The influence of para-seismic vibrations, induced by blasting works, on structures: a Case Study

NASA Astrophysics Data System (ADS)

Andrusikiewicz, Wacław

2018-04-01

Underground mining operations are often associated with the necessity to use explosives. Several hundreds of kilograms of explosives, subdivided into small charges suitable for a specific mining job, are used each time in a blasting operation. In many cases, mining engineers carry out remote central blasting works, which means that all the charges placed at faces are initiated from one control point (usually, a control room in the mine) at the same time. Such coordinated explosions generate para-seismic movements whose consequences can be felt on land surface, with subsequent effects identified in buildings and structures. This paper discusses briefly selected standards applicable to the harmful para-seismic impacts. The author presents the results of the research conducted with the intention to identify harmful effects of the basting works carried out in the "Kłodawa" Salt Mine.

The thermal response of HMX-TATB charges

NASA Astrophysics Data System (ADS)

Drake, R. C.

2017-01-01

One approach to achieving charge safety and performance requirements is to prepare formulations containing two (or more) explosives. The intention of this approach is that by judicious choice of explosives and binder the formulation will have the desirable features of the constituent materials. HMX and TATB have very different properties. In an attempt to achieve a formulation which has the safety and performance characteristics of TATB and HMX, respectively, a range of formulations were prepared. The thermal response of the formulations were measured in the One-Dimensional Time To Explosion (ODTX) configuration and compared to those of formulations containing only HMX and TATB. The response of the mixed formulations was found to be largely determined by the HMX component with the binder making a small contribution. A formulation with a Kel-F 800 binder had a much higher critical temperature than would have been expected based on the critical temperatures of formulations with HTPB-IPDI as the binder.

Numerical modeling of the 1840s major eruption of η Carinae as an explosion

NASA Astrophysics Data System (ADS)

González, Ricardo F.

2018-01-01

In this paper, new two-dimensional hydrodynamical simulations of η Car's nebulae are performed. In the 1840s, the massive star η Car suffered a major eruption that resulted in the formation of a bipolar structure, which is commonly known as the large Homunculus. During this event, η Car expelled into the circumstellar material a total mass of 10 M⊙ and released a total energy of Ek 1050 erg over a very short time (≤5 yr). These kinds of explosive events are frequently called supernova impostors due to their resemblance to a type II supernova, but the stars survive the explosion. In the case of η Car, a brief explosion scenario provides a potential explanation for the behavior of the historical light curve of η Car a few years ( 10 yr) after the nineteenth century outburst. Here, such an alternative scenario of an explosion is assumed (instead of a super-Eddington wind) in order to investigate whether an explosive event is also able to explain the shape and kinematics of the large Homunculus. I show that the numerical simulations presented here indeed resemble some of the observed features of the nebula, such as the present-day double-shell structure of the Homunculus, with a thin outer dense shell and a thicker inner layer, as well as thermal instabilities (Rayleigh-Taylor and Kelvin-Helmholtz) along the dense shell that may lead to the current mottled appearance of the large Homunculus. Nonetheless, the explosion model for the 1840s major eruption of η Car is not able to account for the estimated age of the large Homunculus.

Field measurements and modeling of wave propagation and subsequent weak layer failure in snow due to explosive loading

NASA Astrophysics Data System (ADS)

Simioni, Stephan; Sidler, Rolf; Dual, Jürg; Schweizer, Jürg

2015-04-01

Avalanche control by explosives is among the key temporary preventive measures. Yet, little is known about the mechanism involved in releasing avalanches by the effect of an explosion. Here, we test the hypothesis that the stress induced by acoustic waves exceeds the strength of weak snow layers. Consequently the snow fails and the onset of rapid crack propagation might finally lead to the release of a snow slab avalanche. We performed experiments with explosive charges over a snowpack. We installed microphones above the snowpack to measure near-surface air pressure and accelerometers within three snow pits. We also recorded pit walls of each pit with high speed cameras to detect weak layer failure. Empirical relationships and a priori information from ice and air were used to characterize a porous layered model from density measurements of snow profiles in the snow pits. This model was used to perform two-dimensional numerical simulations of wave propagation in Biot-type porous material. Locations of snow failure were identified in the simulation by comparing the axial and deviatoric stress field of the simulation to the corresponding snow strength. The identified snow failure locations corresponded well with the observed failure locations in the experiment. The acceleration measured in the snowpack best correlated with the modeled acceleration of the fluid relative to the ice frame. Even though the near field of the explosion is expected to be governed by non-linear effects as for example the observed supersonic wave propagation in the air above the snow surface, the results of the linear poroelastic simulation fit well with the measured air pressure and snowpack accelerations. The results of this comparison are an important step towards quantifying the effectiveness of avalanche control by explosives.

Influence of the geometry of protective barriers on the propagation of shock waves

NASA Astrophysics Data System (ADS)

Sochet, I.; Eveillard, S.; Vinçont, J. Y.; Piserchia, P. F.; Rocourt, X.

2017-03-01

The protection of industrial facilities, classified as hazardous, against accidental or intentional explosions represents a major challenge for the prevention of personal injury and property damage, which also involves social and economic issues. We consider here the use of physical barriers against the effects of these explosions, which include the pressure wave, the projection of fragments and the thermal flash. This approach can be recommended for the control of major industrial risks, but no specific instructions are available for its implementation. The influence of a protective barrier against a detonation-type explosion is studied in small-scale experiments. The effects of overpressure are examined over the entire path of the shock wave across the barrier and in the downstream zone to be protected. Two series of barrier structures are studied. The first series (A) of experiments investigates two types of barrier geometry with dimensions based on NATO recommendations. These recommendations stipulate that the barrier should be 2 m higher than the charge height, the thickness at the crest should be more than 0.5 m, while its length should be equal to twice the protected structure length and the bank slope should be equivalent to the angle of repose of the soil. The second series (B) of experiments investigates the influence of geometrical parameters of the barrier (thickness at the crest and inclination angles of the front and rear faces) on its protective effects. This project leads to an advance in our understanding of the physical phenomena involved in the propagation of blast waves resulting from an external explosion, in the area around a protective physical barrier. The study focuses on the dimensioning of protective barriers against overpressure effects arising from detonation and shows the advantage of using a barrier with a vertical front or rear face.

Characterization of Hypervelocity Metal Fragments for Explosive Initiation

NASA Astrophysics Data System (ADS)

Yeager, John; Bowden, Patrick; Guildenbecher, Daniel; Olles, Joseph

2017-06-01

The off-normal detonation behavior of two plastic-bonded explosive (PBX) formulations was studied using explosively-driven aluminum fragments moving at hypersonic velocity. Witness plate materials, including copper and polycarbonate, were used to characterize the distribution of particles, finding that the aluminum did not fragment homogeneously but rather with larger particles in a ring surrounding finer particles. Digital holography experiments were conducted to measure three-dimensional shape and size of the fastest-moving fragments, which ranged between 100 and 700 microns and traveled between 2 and 3.5 km/s. Crucially, these experiments showed variability in the fragmentation in terms of the number of fragments at the leading edge of the fragment field, indicating that both single and multiple shock impacts could be imparted to the target material. Lower density PBX 9407 (RDX-based) was initiable at up to 4.5 inches, while higher density PBX 9501 (HMX-based) was only initiable at up to 0.25 inches. This type of data is critical for safety experiments and hydrocode simulations to quantify shock-to-detonation transition mechanisms and the associated risk-margins for these materials.

Experimental study on the influence of chemical sensitizer on pressure resistance in deep water of emulsion explosives

NASA Astrophysics Data System (ADS)

Liu, Lei; zhang, Zhihua; Wang, Ya; Qin, hao

2018-03-01

The study on the pressure resistance performance of emulsion explosives in deep water can provide theoretical basis for underwater blasting, deep-hole blasting and emulsion explosives development. The sensitizer is an important component of emulsion explosives. By using reusable experimental devices to simulate the charge environment in deep water, the influence of the content of chemical sensitizer on the deep-water pressure resistance performance of emulsion explosives was studied. The experimental results show that with the increasing of the content of chemical sensitizer, the deep-water pressure resistance performance of emulsion explosives gradually improves, and when the pressure is fairly large, the effect is particularly pronounced; in a certain range, with the increase of the content of chemical sensitizer, that emulsion explosives’ explosion performance also gradually improve, but when the content reaches a certain value, the explosion properties declined instead; under the same emulsion matrix condition, when the content of NANO2 is 0.2%, that the emulsion explosives has good resistance to water pressure and good explosion properties. The correctness of the results above was testified in model blasting.

A new type of localized fast moving electronic excitations in molecular chains

NASA Astrophysics Data System (ADS)

Korshunova, A. N.; Lakhno, V. D.

2014-06-01

It is shown that in a Holstein molecular chain placed in a strong longitudinal electric field some new types of excitations can arise. These excitations can transfer a charge over large distance (more than 1000 nucleotide pairs) along the chain retaining approximately their shapes. Excitations are formed only when a strong electric field either exists or quickly arises under especially preassigned conditions. These excitations transfer a charge even in the case when Holstein polarons are practically immobile. The results obtained are applied to synthetic homogeneous PolyG/PolyC DNA duplexes. They can also be provide the basis for explanation of famous H.W. Fink and C. Schönenberger experiment on long-range charge transfer in DNA.

Totally confined explosive welding

NASA Technical Reports Server (NTRS)

Bement, L. J. (Inventor)

1978-01-01

The undesirable by-products of explosive welding are confined and the association noise is reduced by the use of a simple enclosure into which the explosive is placed and in which the explosion occurs. An infrangible enclosure is removably attached to one of the members to be bonded at the point directly opposite the bond area. An explosive is completely confined within the enclosure at a point in close proximity to the member to be bonded and a detonating means is attached to the explosive. The balance of the enclosure, not occupied by explosive, is filled with a shaped material which directs the explosive pressure toward the bond area. A detonator adaptor controls the expansion of the enclosure by the explosive force so that the enclosure at no point experiences a discontinuity in expansion which causes rupture. The use of the technique is practical in the restricted area of a space station.

Sensitivity to friction for primary explosives.

PubMed

Matyáš, Robert; Šelešovský, Jakub; Musil, Tomáš

2012-04-30

The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature. Copyright © 2012 Elsevier B.V. All rights reserved.

2009 Insensitive Munitions and Energetic Materials Technology Symposium

DTIC Science & Technology

2009-05-14

Multilayer Structure 1D STIMULI Flat end rod Round end rod Flat cookie -cutter Spherical fragment Simple shaped charge jet Real shaped charge jet Thin plate... cookie -cutter Spherical fragment Simple shaped charge jet Real shaped charge jet Thin plate Constant Temperature Rising Temperature Multilayer...Propellants  Plasticizer mixed into the Propellant - Dough NO SURFACE COATING Formulation Impetus (J/g) Flame Temp (K) Mw (g/mole) A

A velocity probe-based method for continuous detonation and shock measurement in near-field underwater explosion.

PubMed

Li, Kebin; Li, Xiaojie; Yan, Honghao; Wang, Xiaohong; Miao, Yusong

2017-12-01

A new velocity probe which permits recording the time history of detonation and shock waves has been developed by improving the commercial on principle and structure. A method based on the probe is then designed to measure the detonation velocity and near-field shock parameters in a single underwater explosion, by which the oblique shock wave front of cylindrical charges and the peak pressure attenuation curve of spherical explosive are obtained. A further derivation of detonation pressure, adiabatic exponent, and other shock parameters is conducted. The present method offers a novel and reliable parameter determination for near-field underwater explosion.

A velocity probe-based method for continuous detonation and shock measurement in near-field underwater explosion

NASA Astrophysics Data System (ADS)

Li, Kebin; Li, Xiaojie; Yan, Honghao; Wang, Xiaohong; Miao, Yusong

2017-12-01

A new velocity probe which permits recording the time history of detonation and shock waves has been developed by improving the commercial on principle and structure. A method based on the probe is then designed to measure the detonation velocity and near-field shock parameters in a single underwater explosion, by which the oblique shock wave front of cylindrical charges and the peak pressure attenuation curve of spherical explosive are obtained. A further derivation of detonation pressure, adiabatic exponent, and other shock parameters is conducted. The present method offers a novel and reliable parameter determination for near-field underwater explosion.

An Anion-Induced Hydrothermal Oriented-Explosive Strategy for the Synthesis of Porous Upconversion Nanocrystals

PubMed Central

Qiu, Peiyu; Sun, Rongjin; Gao, Guo; Zhang, Chunlei; Chen, Bin; Yan, Naishun; Yin, Ting; Liu, Yanlei; Zhang, Jingjing; Yang, Yao; Cui, Daxiang

2015-01-01

Rare-earth (RE)-doped upconversion nanocrystals (UCNCs) are deemed as the promising candidates of luminescent nanoprobe for biological imaging and labeling. A number of methods have been used for the fabrication of UCNCs, but their assembly into porous architectures with desired size, shape and crystallographic phase remains a long-term challenging task. Here we report a facile, anion-induced hydrothermal oriented-explosive method to simultaneously control size, shape and phase of porous UCNCs. Our results confirmed the anion-induced hydrothermal oriented-explosion porous structure, size and phase transition for the cubic/hexagonal phase of NaLuF4 and NaGdF4 nanocrystals with various sizes and shapes. This general method is very important not only for successfully preparing lanthanide doped porous UCNCs, but also for clarifying the formation process of porous UCNCs in the hydrothermal system. The synthesized UCNCs were used for in vitro and in vivo CT imaging, and could be acted as the potential CT contrast agents. PMID:25767613

Measurement of Afterburning Effect of Underoxidized Explosives by Underwater Explosion Method

NASA Astrophysics Data System (ADS)

Cao, Wei; He, Zhongqi; Chen, Wanghua

2015-04-01

The afterburning effect of TNT and a desensitized hexogen RDX-Al explosive was studied in a defined gas volume under water. A double-layer container (DLC) filled with different gases (air, oxygen, and nitrogen) was used to control and distinguish the afterburning effect of explosives. After the charges in the DLC were initiated under water, the shock wave signals were collected and analyzed. It is shown that shock wave peak pressures are duly in compliance with explosion similarity law, pressure, and impulse histories for explosions in oxygen and air are greater than those recorded for explosions in nitrogen due to the afterburing reaction. Moreover, the afterburning energy was calculated. Results show that even though there is excess oxygen in the gas volume, the afterburning energy may not reach the theoretically maximum value. This result is different from that in confined explosion, where the presence of excess oxygen in the compressed gas filling a bomb leads to complete combustion of the detonation products.

Static electricity as a hazard in industry

NASA Astrophysics Data System (ADS)

van Laar, Ir. G. F. M.

1991-08-01

Looking at the German and Dutch statistics, the percentage of dust explosions in all industries dealing with explosible dust-air mixtures which have been ignited by electrostatic discharges is about 8-10%. However, in the plastics industry this value is much higher: 25%. In particular in the last few years some rather large industrial incidents probably have been caused by electrostatic charges. To understand why accidents may happen due to static electricity the several dangerous electrostatic discharges will be discussed briefly in connection with dust explosion hazards. In particular the propagating brush discharge and the cone or " Maurer " discharge are important. Ignitions are caused mainly in the case of easily ignitable powders or hybrid mixtures (powders in combination with flammable vapours) due to isolated conductors and non-conducting materials as the product itself or such process parts as flexible hoses, internally coated silos and ducts. To illustrate how hazards by electrostatic discharges may develop in real life both on a small and a large scale a few examples will be briefly discussed. Une consultation des statistiques allemandes et néerlandaises révèle que dans toutes les industries traitant des mélanges poussière-air explosifs le pourcentage des explosions de poussière qui se sont produites par des décharges électrostatiques ne s'élève qu'à environ 8-10 %. Dans l'industrie des matières plastiques cependant, ce pourcentage est bien plus grand: 25 %. Les dernières années en particulier nous ont rapporté plusieurs incidents industriels assez graves qui sont probablement causés par des charges électrostatiques. Pour comprendre comment des accidents pareils dus à l'électricité statique peuvent se produire, les différentes décharges électrostatiques dangereuses pouvant produire des explosions de poussière se discuteront brièvement. Ce sont surtout la décharge brosse de surface et la décharge " Maurer " qui sont d'une importance considérable. Les inflammations se font principalement en cas de poussières combustibles ou mélanges hybrides (des poudres en combinaison avec des vapeurs combustibles) par des conducteurs isolés et des matériaux non conductibles comme le produit même ou par des éléments concernés comme des tuyaux flexibles, des silos couverts à l'intérieur et des tubes. Afin d'illustrer comment des dangers par décharges électrostatiques sur petite comme sur grande échelle pourraient se développer dans la vie quotidienne, quelques exemples seront donnés.

27 CFR 555.203 - Types of magazines.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Types of magazines. 555... EXPLOSIVES, DEPARTMENT OF JUSTICE EXPLOSIVES COMMERCE IN EXPLOSIVES Storage § 555.203 Types of magazines. For purposes of this part, there are five types of magazines. These types, together with the classes of...

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNesby, Kevin L.; Homan, Barrie E.; Benjamin, Richard A.

Here, the techniques presented in this paper allow for mapping of temperature, pressure, chemical species, and energy deposition during and following detonations of explosives, using high speed cameras as the main diagnostic tool. Additionally, this work provides measurement in the explosive near to far-field (0-500 charge diameters) of surface temperatures, peak air-shock pressures, some chemical species signatures, shock energy deposition, and air shock formation.

On the low pressure shock initiation of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine based plastic bonded explosives

NASA Astrophysics Data System (ADS)

Vandersall, Kevin S.; Tarver, Craig M.; Garcia, Frank; Chidester, Steven K.

2010-05-01

In large explosive and propellant charges, relatively low shock pressures on the order of 1-2 GPa impacting large volumes and lasting tens of microseconds can cause shock initiation of detonation. The pressure buildup process requires several centimeters of shock propagation before shock to detonation transition occurs. In this paper, experimentally measured run distances to detonation for lower input shock pressures are shown to be much longer than predicted by extrapolation of high shock pressure data. Run distance to detonation and embedded manganin gauge pressure histories are measured using large diameter charges of six octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) based plastic bonded explosives (PBX's): PBX 9404; LX-04; LX-07; LX-10; PBX 9501; and EDC37. The embedded gauge records show that the lower shock pressures create fewer and less energetic "hot spot" reaction sites, which consume the surrounding explosive particles at reduced reaction rates and cause longer distances to detonation. The experimental data is analyzed using the ignition and growth reactive flow model of shock initiation in solid explosives. Using minimum values of the degrees of compression required to ignite hot spot reactions, the previously determined high shock pressure ignition and growth model parameters for the six explosives accurately simulate the much longer run distances to detonation and much slower growths of pressure behind the shock fronts measured during the shock initiation of HMX PBX's at several low shock pressures.

Reactive Blast Waves from Composite Charges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhl, A L; Bell, J B; Beckner, V E

2009-10-16

Investigated here is the performance of composite explosives - measured in terms of the blast wave they drive into the surrounding environment. The composite charge configuration studied here was a spherical booster (1/3 charge mass), surrounded by aluminum (Al) powder (2/3 charge mass) at an initial density of {rho}{sub 0} = 0.604 g/cc. The Al powder acts as a fuel but does not detonate - thereby providing an extreme example of a 'non-ideal' explosive (where 2/3 of the charge does not detonate). Detonation of the booster charge creates a blast wave that disperses the Al powder and ignites the ensuingmore » Al-air mixture - thereby forming a two-phase combustion cloud embedded in the explosion. Afterburning of the booster detonation products with air also enhances and promotes the Al-air combustion process. Pressure waves from such reactive blast waves have been measured in bomb calorimeter experiments. Here we describe numerical simulations of those experiments. A Heterogeneous Continuum Model was used to model the dispersion and combustion of the Al particle cloud. It combines the gasdynamic conservation laws for the gas phase with a dilute continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models of Khasainov. It incorporates a combustion model based on mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Adaptive Mesh Refinement (AMR) was used to capture the energy-bearing scales of the turbulent flow on the computational grid, and to track/resolve reaction zones. Numerical simulations of the explosion fields from 1.5-g and 10-kg composite charges were performed. Computed pressure histories (red curve) are compared with measured waveforms (black curves) in Fig. 1. Comparison of these results with a waveform for a non-combustion case in nitrogen (blue curve) demonstrates that a reactive blast wave was formed. Cross-sectional views of the temperature field at various times are presented in Fig. 2, which shows that the flow is turbulent. Initially, combustion occurs at the fuel-air interface, and the energy release rate is controlled by the rate of turbulent mixing. Eventually, oxidizer becomes distributed throughout the cloud via ballistic mixing of the particles with air; energy release then occurs in a distributed combustion mode, and Al particle kinetics controls the energy release rate. Details of the Heterogeneous Continuum Model and results of the numerical simulations of composite charge explosions will be described in the paper.« less

HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reaugh, J E

2011-11-22

HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the responsemore » of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for reliable performance, whether as a result of accident, hazard, or a fault in the detonation train. These models describe the build-up of detonation from a shock stimulus. They are generally consistent with the mesoscale picture of ignition at many small defects in the plane of the shock front and the growth of the resulting hot-spots, leading to detonation in heterogeneous explosives such as plastic-bonded explosives (PBX). The models included terms for ignition, and also for the growth of reaction as tracked by the local mass fraction of product gas, {lambda}. The growth of reaction in such models incorporates a form factor that describes the change of surface area per unit volume (specific surface area) as the reaction progresses. For unimolecular crystalline-based explosives, the form factor is consistent with the mesoscale picture of a galaxy of hot spots burning outward and eventually interacting with each other. For composite explosives and propellants, where the fuel and oxidizer are segregated, the diffusion flame at the fuel-oxidizer interface can be interpreted with a different form factor that corresponds to grains burning inward from their surfaces. The form factor influences the energy release rate, and the amount of energy released in the reaction zone. Since the 19th century, gun and cannon propellants have used perforated geometric shapes that produce an increasing surface area as the propellant burns. This helps maintain the pressure as burning continues while the projectile travels down the barrel, which thereby increases the volume of the hot gas. Interior ballistics calculations use a geometric form factor to describe the changing surface area precisely. As a result, with a suitably modified form factor, detonation models can represent burning and explosion in damaged and broken reactant. The disadvantage of such models in application to accidents is that the ignition term does not distinguish between a value of pressure that results from a shock, and the same pressure that results from a more gradual increase. This disagrees with experiments, where explosives were subjected to a gradual rise in pressure and did not exhibit reaction. More recent models do distinguish between slow pressure rises and shocks, and have had some success in the describing the response of explosives to single and multiple shocks, and the increase of shock sensitivity with porosity, at least over a limited range. The original formulation is appropriate for sustained shocks, but further work is ongoing to describe the response to short pulses. The HERMES model combines features from these prior models. It describes burning and explosion in damaged reactant, and also will develop a detonation if the gradual rise in pressure from burning steepens into a strong-enough shock. The shock strength needed for detonation in a fixed run distance decreases with increasing porosity.« less

The Skylab barium plasma injection experiments. I - Convection observations

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Peek, H. M.

1976-01-01

Two barium-plasma injection experiments were carried out during magnetically active periods in conjunction with the Skylab 3 mission. The high-explosive shaped charges were launched near dawn on November 27 and December 4, 1973, UT. In both cases, the AE index was near 400 gammas, and extensive pulsating auroras covered the sky. The first experiment, Skylab Alpha, occurred in the waning phase of a 1000-gamma substorm, and the second, Skylab Beta, occurred in the expansive phase of an 800-gamma substorm. In both, the convection was generally magnetically eastward, with 100-km-level electric fields near 40 mV/m. However, in the Alpha experiment the observed orientation of the barium flux tube fit theoretical field lines having no parallel current, but the Beta flux-tube orientation indicated a substantial upward parallel sheet current.

KSC-99pp1240

NASA Image and Video Library

1999-10-14

KENNEDY SPACE CENTER, FLA. — Two 34-year-old towers on Launch Complex 41, Cape Canaveral Air Station, fall to the ground amid the black smoke from explosives set to topple them. Weighing two million pounds, the umbilical tower (left) was approximately 200 feet high. The taller 300-foot Mobile Service Tower (right), still falling, weighs five million pounds. About 200 pounds of linear-shaped charges were used to topple the towers so that the materials can be recycled. Adjacent to the towers are lightning protection structures, which will remain on the site. The towers are being demolished to make room for Lockheed Martin's 14-acre Vehicle Integration Facility (VIF), under construction. The implosion and removal of the tower debris is expected to be completed in two months. The VIF will be used for Lockheed Martin's Atlas V Launch System.

Blast-Absorbing Bag

NASA Technical Reports Server (NTRS)

Kahn, Jon B.

1992-01-01

Proposed expandable bag contains debris from explosion. Permanently surrounds vessel or devices prone to explosive disintegration or slipped around small bomb. Finned cells shaped like outward-opening cups. Cells built up from overlapped sheets of fabric and stitched together to form expandable polyhedral bag. Cells pentagonal, triangular or square.

Method for laser machining explosives and ordnance

DOEpatents

Muenchausen, Ross E.; Rivera, Thomas; Sanchez, John A.

2003-05-06

Method for laser machining explosives and related articles. A laser beam is directed at a surface portion of a mass of high explosive to melt and/or vaporize the surface portion while directing a flow of gas at the melted and/or vaporized surface portion. The gas flow sends the melted and/or vaporized explosive away from the charge of explosive that remains. The method also involves splitting the casing of a munition having an encased explosive. The method includes rotating a munition while directing a laser beam to a surface portion of the casing of an article of ordnance. While the beam melts and/or vaporizes the surface portion, a flow of gas directed at the melted and/or vaporized surface portion sends it away from the remaining portion of ordnance. After cutting through the casing, the beam then melts and/or vaporizes portions of the encased explosive and the gas stream sends the melted/vaporized explosive away from the ordnance. The beam is continued until it splits the article, after which the encased explosive, now accessible, can be removed safely for recycle or disposal.

Explosive Welding of Aluminum, Titanium and Zirconium to Copper Sheet Metal

NASA Technical Reports Server (NTRS)

Hegazy, A. A.; Mote, J. D.

1985-01-01

The main material properties affecting the explosive weldability of a certain metal combination are the yield strength, the ductility, the density and the sonic velocity of the two metals. Successful welding of the metal combination depends mainly on the correct choice of the explosive welding parameters; i.e., the stand off distance, the weight of the explosive charge relative to the weight of the flyer plate and the detonation velocity of the explosive. Based on the measured and the handbook values of the properties of interest, the explosive welding parameters were calculated and the arrangements for the explosive welding of the Al alloy 6061-T6, titanium and zirconium to OFHC copper were determined. The relatively small sheet metal thickness (1/8") and the fact that the thickness of the explosive layer must exceed a certain minimum value were considered during the determination of the explosive welding conditions. The results of the metallographic investigations and the measurements of the shear strength at the interface demonstrate the usefulness of these calculations to minimize the number of experimental trials.

The Shape of Superluminous Supernovae

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-11-01

What causes the tremendous explosions of superluminous supernovae? New observations reveal the geometry of one such explosion, SN 2015bn, providing clues as to its source.A New Class of ExplosionsImage of a type Ia supernova in the galaxy NGC 4526. [NASA/ESA]Supernovae are powerful explosions that can briefly outshine the galaxies that host them. There are several different classifications of supernovae, each with a different physical source such as thermonuclear instability in a white dwarf, caused by accretion of too much mass, or the exhaustion of fuel in the core of a massive star, leading to the cores collapse and expulsion of its outer layers.In recent years, however, weve detected another type of supernovae, referred to as superluminous supernovae. These particularly energetic explosions last longer months instead of weeks and are brighter at their peaks than normal supernovae by factors of tens to hundreds.The physical cause of these unusual explosions is still a topic of debate. Recently, however, a team of scientists led by Cosimo Inserra (Queens University Belfast) has obtained new observations of a superluminous supernova that might help address this question.The flux and the polarization level (black lines) along the dominant axis of SN 2015bn, 24 days before peak flux (left) and 28 days after peak flux (right). Blue lines show the authors best-fitting model. [Inserra et al. 2016]Probing GeometryInserra and collaborators obtained two sets of observations of SN 2015bn one roughly a month before and one a month after the superluminous supernovas peak brightness using a spectrograph on the Very Large Telescope in Chile. These observations mark the first spectropolarimetric data for a superluminous supernova.Spectropolarimetry is the practice of obtaining information about the polarization of radiation from an objects spectrum. Polarization carries information about broken spatial symmetries in the object: only if the object is perfectly symmetric can it emit an unpolarized spectrum. Otherwise, the polarization of an objects spectrum reveals information about its geometry.Modeling EjectaThe authors best model of the geometry of SN 2015bn 24 days before (top) and 28 days after (bottom) peak flux. The model consists of two ellipsoidal layers of ejecta material. [Inserra et al. 2016]Based on their observations, Inserra and collaborators find that SN 2015bn is not spherically symmetric but it does appear to be axisymmetric around a single dominant axis. They also find that the polarization level of the object changes both with wavelength and over time.To explain these dependencies, the authors produce a simple toy model of SN 2015bn. In the best-fitting model, the supernova has a two-layered ellipsoidal or bipolar geometry. The inner region becomes more and more aspherical as time passes.What does this model tell us about the physical cause of this superluminous supernova? Inserra and collaborators argue that the axisymmetric shape favors a core-collapse explosion. A central inner engine of a spinning magnetar (a highly magnetized neutron star) or black hole then remains at the center of this explosion, pumping energy into it and causing the increase of the inner asymmetry over time.The authors caution that their models are very preliminary but these observations should drive future, more detailed modeling, as well as further spectropolarimetric observations of future nearby superluminous supernovae. With luck, we will soon better understand what drives these unusual explosions.CitationC. Inserra et al 2016 ApJ 831 79. doi:10.3847/0004-637X/831/1/79

Universality of fragment shapes.

PubMed

Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

2015-03-16

The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

Universality of fragment shapes

PubMed Central

Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

2015-01-01

The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism. PMID:25772300

Space charge effect in spectrometers of ion mobility increment with cylindrical drift chamber.

PubMed

Elistratov, A A; Sherbakov, L A

2007-01-01

We have amplified the model for the drift of ions under a non-uniform high-frequency electric field by taking space charge effect into account. By this means, we have investigated the effect of space charge on the dynamics of a single type of ions in a spectrometer of ion mobility increment with a cylindrical drift chamber. The counteraction of the space charge effect and the focusing effect is investigated. The output ion current saturation caused by the effect of the space charge is observed. The shape of the ion peak taking into consideration the space charge effect has been obtained. We show that the effect of the space charge is sufficient for the relative ion density greater than 10 ppt by order of magnitude (for a cylindrical geometry spectrometer with typical parameters).

Reactive Flow Modeling of Liquid Explosives via ALE3D/Cheetah Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, I W; Bastea, S; Fried, L E

2010-03-10

We carried out reactive flow simulations of liquid explosives such as nitromethane using the hydrodynamic code ALE3D coupled with equations of state and reaction kinetics modeled by the thermochemical code Cheetah. The simulation set-up was chosen to mimic cylinder experiments. For pure unconfined nitromethane we find that the failure diameter and detonation velocity dependence on charge diameter are in agreement with available experimental results. Such simulations are likely to be useful for determining detonability and failure behavior for a wide range of experimental conditions and explosive compounds.

Investigation of charge weight and shock factor effect on non-linear transient structural response of rectangular plates subjected to underwater explosion (UNDEX) shock loading

NASA Astrophysics Data System (ADS)

Demir, Ozgur; Sahin, Abdurrahman; Yilmaz, Tamer

2012-09-01

Underwater explosion induced shock loads are capable of causing considerable structural damage. Investigations of the underwater explosion (UNDEX) effects on structures have seen continuous developments because of security risks. Most of the earlier experimental investigations were performed by military since the World War I. Subsequently; Cole [1] established mathematical relations for modeling underwater explosion shock loading, which were the outcome of many experimental investigations This study predicts and establishes the transient responses of a panel structure to underwater explosion shock loads using non-linear finite element code Ls-Dyna. Accordingly, in this study a new MATLAB code has been developed for predicting shock loading profile for different weight of explosive and different shock factors. Numerical analysis was performed for various test conditions and results are compared with Ramajeyathilagam's experimental study [8].

Profiling charge complementarity and selectivity for binding at the protein surface.

PubMed

Sulea, Traian; Purisima, Enrico O

2003-05-01

A novel analysis and representation of the protein surface in terms of electrostatic binding complementarity and selectivity is presented. The charge optimization methodology is applied in a probe-based approach that simulates the binding process to the target protein. The molecular surface is color coded according to calculated optimal charge or according to charge selectivity, i.e., the binding cost of deviating from the optimal charge. The optimal charge profile depends on both the protein shape and charge distribution whereas the charge selectivity profile depends only on protein shape. High selectivity is concentrated in well-shaped concave pockets, whereas solvent-exposed convex regions are not charge selective. This suggests the synergy of charge and shape selectivity hot spots toward molecular selection and recognition, as well as the asymmetry of charge selectivity at the binding interface of biomolecular systems. The charge complementarity and selectivity profiles map relevant electrostatic properties in a readily interpretable way and encode information that is quite different from that visualized in the standard electrostatic potential map of unbound proteins.

Radiographic techniques in the explosive component facility at Sandia National Labs.

NASA Astrophysics Data System (ADS)

Lanoue, John C.

1997-05-01

The Explosive Component Facility at Sandia National Laboratory is a state of the art facility for the design and testing of energetic materials and components. Two key elements of these capabilities are the flash x-ray machines. One is a six head, 150 KeV and the other is a six head, 300 KeV instrument. One of the more interesting uses of the 150 KeV system has been to study the action and reaction of a linear shaped charge (LSC) while submerged in water. The submerged samples were viewed from the top to capture the interaction of one piece of LSC with another piece nearby. Each LSC was covered by separate rubber coverings and affixed to a composite-plate. Three heads, delayed by a specified time, were used to capture the time sequence of events in stop action. Side views of the LSC were done with and without the rubber coverings to examine the dampening effects of the cover. An end-on perspective was also captured by x-ray using one head and several time delays. The debris scatter produced from a larger device has also been examined. The explosive used was a pellet form initiated by a detonator and a timing lead. The x-ray radiographs show the particles from this device as they expand outward. Three x-ray source tubes were used in a large horizontal array, apertured to expose individual pieces of film. Another x-ray source was placed overhead and simultaneously exposed a film under the object.

Experiments on water/melt explosions, nature of products, and models of dispersal

NASA Technical Reports Server (NTRS)

Sheridan, M. F.; Wohletz, K. H.

1984-01-01

Experiments were carried out in a steel pressure device using controlled amounts of water and thermite melt to examine the mechanical energy released on explosive mixing following the initial contact of the two materials. An experimental design was used to allow the direct calculation of the mechanical energy by the dynamic lift of the device as recorded both optically and physically. A large number of experiments were run to accurately determine the optimum mixture of water and melt for the conversion of thermal to mechanical energy. The maximum efficiency observed was about 12% at a water/thermite mass ratio of 0.50. These experiments are the basis for the development of models of hydroexplosions and melt fragmentation. Particles collected from the experimental products are similar in size and shape to pyroclasts produced by much larger hydrovolcanic explosions. Melt rupture at optimum ratios produces very fine particles whereas rupture at high or low water/melt ratios produces large melt fragments. Grain surface textures in the experimental products are also related to the water/melt ratio and the mechanism of explosive mixing. It is thus possible to have qualitative information about the nature of the explosion from the sizes and shapes of the fragments produced.

Shock Initiation of Wedge-shaped Explosive Measured with Smear Camera and Photon Doppler Velocimetry

NASA Astrophysics Data System (ADS)

Gu, Yan

2017-06-01

Triaminotrinitrobenzene (TATB) is an important insensitive high explosive in conventional weapons due to its safety and high energy. In order to have an insight into the shock initiation performance of a TATB-based insensitive high explosive (IHE), experimental measurements of the particle velocity histories of the TATB-based Explosive using Photon Doppler Velocimetry and shock wave profile of the TATB-based explosive using High Speed Rotating Mirror Smear Camera had been performed. In this paper, we would describe the shock initiation performance of the TATB-based explosive by run-to-detonation distance and the particle velocity history at an initialization shock of about 7.9 GPa. The parameters of hugoniot of unreacted the TATB-based explosive and Pop relationship could be derived with the particle velocity history obtained in this paper.

Shelf life extension for the lot AAE nozzle severance LSCs

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Shelf life extension tests for the remaining lot AAE linear shaped charges for redesigned solid rocket motor nozzle aft exit cone severance were completed in the small motor conditioning and firing bay, T-11. Five linear shaped charge test articles were thermally conditioned and detonated, demonstrating proper end-to-end charge propagation. Penetration depth requirements were exceeded. Results indicate that there was no degradation in performance due to aging or the linear shaped charge curving process. It is recommended that the shelf life of the lot AAE nozzle severance linear shaped charges be extended through January 1992.

Amphipathic peptide affects the lateral domain organization of lipid bilayers.

PubMed

Polozov, I V; Polozova, A I; Molotkovsky, J G; Epand, R M

1997-09-04

Using lipid-specific fluorescent probes, we studied the effects of amphipathic helical, membrane active peptides of the A- and L-type on membrane domain organization. In zwitterionic binary systems composed of mixtures of phosphatidylcholine and phosphatidylethanolamine, both types of peptides associated with the fluid phase. While binding with high affinity to fluid membranes, peptides were unable to penetrate into the lipid membrane in the gel state. If trapped kinetically by cooling from the fluid phase, peptides dissociated from the gel membrane on the time scale of several hours. While the geometrical shape of the alpha-helical peptides determines their interactions with membranes with non-bilayer phase propensity, the shape complementarity mechanism by itself is unable to induce lateral phase separation in a fluid membrane. Charge-charge interactions are capable of inducing lateral domain formation in fluid membranes. Both peptides had affinity for anionic lipids which resulted in about 30% enrichment of acidic lipids within several nanometers of the peptide's tryptophan, but there was no long-range order in peptide-induced lipid demixing. Peptide insertion in fluid acidic membranes was accompanied by only a small increase in bilayer surface and a decrease in polarity in the membrane core. Peptide-lipid charge-charge interactions were also capable of modulating existing domain composition in the course of the main phase transition in mixtures of anionic phosphatidylglycerol with zwitterionic phosphatidylcholine.

Magnetic fields for transporting charged beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parzen, G.

1976-01-01

The transport of charged particle beams requires magnetic fields that must be shaped correctly and very accurately. During the last 20 years or so, many studies have been made, both analytically and through the use of computer programs, of various magnetic shapes that have proved to be useful. Many of the results for magnetic field shapes can be applied equally well to electric field shapes. A report is given which gathers together the results that have more general significance and would be useful in designing a configuration to produce a desired magnetic field shape. The field shapes studied include themore » fields in dipoles, quadrupoles, sextupoles, octupoles, septum magnets, combined-function magnets, and electrostatic septums. Where possible, empirical formulas are proposed, based on computer and analytical studies and on magnetic field measurements. These empirical formulas are often easier to use than analytical formulas and often include effects that are difficult to compute analytically. In addition, results given in the form of tables and graphs serve as illustrative examples. The field shapes studied include uniform fields produced by window-frame magnets, C-magnets, H-magnets, and cosine magnets; linear fields produced by various types of quadrupoles; quadratic and cubic fields produced by sextupoles and octupoles; combinations of uniform and linear fields; and septum fields with sharp boundaries.« less

Soft container for explosive nuts

NASA Technical Reports Server (NTRS)

Glenn, D. C.; Drummond, W. E.; Miller, G.

1981-01-01

Flexible fabric fits over variety of assembly shapes to contain debris produced by detonations or safety tests. Bag material is woven multifilament polyamide or aramid. Belt loops hold bag to clamp. Ring supports explosive nut structure and detonator wires, and after nut is mounted, bag and clamp are slipped over ring and fastened.

Predicting stability limits for pure and doped dicationic noble gas clusters undergoing coulomb explosion: A parallel tempering based study.

PubMed

Ghorai, Sankar; Chaudhury, Pinaki

2018-05-30

We have used a replica exchange Monte-Carlo procedure, popularly known as Parallel Tempering, to study the problem of Coulomb explosion in homogeneous Ar and Xe dicationic clusters as well as mixed Ar-Xe dicationic clusters of varying sizes with different degrees of relative composition. All the clusters studied have two units of positive charges. The simulations reveal that in all the cases there is a cutoff size below which the clusters fragment. It is seen that for the case of pure Ar, the value is around 95 while that for Xe it is 55. For the mixed clusters with increasing Xe content, the cutoff limit for suppression of Coulomb explosion gradually decreases from 95 for a pure Ar to 55 for a pure Xe cluster. The hallmark of this study is this smooth progression. All the clusters are simulated using the reliable potential energy surface developed by Gay and Berne (Gay and Berne, Phys. Rev. Lett. 1982, 49, 194). For the hetero clusters, we have also discussed two different ways of charge distribution, that is one in which both positive charges are on two Xe atoms and the other where the two charges are at a Xe atom and at an Ar atom. The fragmentation patterns observed by us are such that single ionic ejections are the favored dissociating pattern. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

The Progenitor and Remnant of the Helium Nova V445 Puppis

NASA Astrophysics Data System (ADS)

Goranskij, V.; Shugarov, S.; Zharova, A.; Kroll, P.; Barsukova, E. A.

2010-10-01

V445 Pup was a peculiar nova with no hydrogen spectral lines during the outburst. The spectrum contained strong emission lines of carbon, oxygen, calcium, sodium, and iron. We have performed digital processing of photographic images of the V445 Pup progenitor using astronomical plate archives. The brightness of the progenitor in the B band was 14.3m. It was a periodic variable star, its most probable period being 0.650654+/-0.000011 days. The light curve shape suggests that the progenitor was a common-envelope binary with a spot on the surface and variable surface brightness. The spectral energy distribution of the progenitor between 0.44 and 2.2 microns was similar to that of an A0V type star. After the explosion in 2001, the dust was formed in the ejecta, and the star became a strong infrared source. This resulted in the star's fading below 20m in the V band. Our CCD BVR observations acquired between 2003 and 2009 suggest that the dust absorption minimum finished in 2004, and the remnant reappeared at the level of 18.5m V. The dust dispersed but a star-like object was absent in frames taken in the K band with the VLT adaptive optics. Only expanding ejecta of the explosion were seen in these frames till March 2007. No reddened A0V type star reappeared in the spectral energy distribution. The explosion of V445 Pup in 2000 was a helium flash on the surface of a CO-type white dwarf. Taking into account the results of modern dynamic calculations, we discuss the possibility of a white-dwarf core detonation triggered by the helium flash and the observational evidence for it. Additionally, the common envelope of the system was lost in the explosion. Destruction in the system and mass loss from its components exclude the future SN Ia scenario for V445 Pup.

Precursor detonation wave development in ANFO due to aluminum confinement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Scott I; Klyanda, Charles B; Short, Mark

2010-01-01

Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could decrease the explosive performance by crushing porosity required for initiation by shock compression or destroying confinement ahead of the detonation. At present, these phenomena are not well understood. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understandingmore » and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by a 76-mm-inner-diameter aluminum confining tube. Detonation velocity, detonation-front shape, and aluminum response are recorded as a function of confiner wall thickness and length. Detonation shape profiles display little curvature near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness, while wavefront curvature decreased due to the stiffer, subsonic confinement. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected, which interfered with the front shape measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation by modifying its characteristic shape.« less

Reaction of Titanium and Zirconium Particles in Cylindrical Explosive Charges

NASA Astrophysics Data System (ADS)

Frost, David; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2007-06-01

The critical conditions for the reaction of high melting-point metallic particles (Ti, Zr) dispersed during the detonation of long cylindrical explosive charges have been investigated experimentally. The charges consisted of packed beds of either spherical titanium particles (with diameters of 35, 90, or 215 μm; AP&C, Inc.) or nonspherical zirconium particles (250 -- 500 μm or 500 -- 600 μm, Atlantic Equipment Eng., NJ) saturated with sensitized liquid nitromethane. For the titanium particles, a threshold particle diameter exists, above which self-sustained particle reaction is not observed, although some particle reaction occurs immediately behind the detonation front then rapidly quenches. For the smallest particles, the proportion of the conical particle cloud that reacts increases with charge diameter, suggesting that the reaction initiation is a competition between particle heating and expansion cooling of the products. For zirconium particles, no critical conditions exist; particle ignition was observed for all particle and charge diameters tested. In this case, interaction of the high pressure detonation wave with the particles is sufficient to initiate reaction at the particle surface after a delay time (˜ 10's μs), which is much less than the time required for thermal equilibration of the particles.

The equivalent depth of burst for impact cratering

NASA Technical Reports Server (NTRS)

Holsapple, K. A.

1980-01-01

The concept of modeling an impact cratering event with an explosive event with the explosive buried at some equivalent depth of burst (d.o.b.) is discussed. Various and different ways to define this equivalent d.o.b. are identified. Recent experimental results for a dense quartz sand are used to determine the equivalent d.o.b. for various conditions of charge type, event size, and impact conditions. The results show a decrease in equivalent d.o.b. with increasing energy for fixed impact velocity and a decrease in equivalent d.o.b. with increasing velocity for fixed energy. The values for an iron projectile are on the order of 2-3 projectile radii for energy equal to one ton of TNT, decreasing to about 1.5 radii at a megaton of TNT. The dependence on projectile and target mass density matches that included in common jet-penetration formulas for projectile densities greater than target densities and for the higher energies.

Safety Testing of Ammonium Nitrate Based Mixtures

NASA Astrophysics Data System (ADS)

Phillips, Jason; Lappo, Karmen; Phelan, James; Peterson, Nathan; Gilbert, Don

2013-06-01

Ammonium nitrate (AN)/ammonium nitrate based explosives have a lengthy documented history of use by adversaries in acts of terror. While historical research has been conducted on AN-based explosive mixtures, it has primarily focused on detonation performance while varying the oxygen balance between the oxidizer and fuel components. Similarly, historical safety data on these materials is often lacking in pertinent details such as specific fuel type, particle size parameters, oxidizer form, etc. A variety of AN-based fuel-oxidizer mixtures were tested for small-scale sensitivity in preparation for large-scale testing. Current efforts focus on maintaining a zero oxygen-balance (a stoichiometric ratio for active chemical participants) while varying factors such as charge geometry, oxidizer form, particle size, and inert diluent ratios. Small-scale safety testing was conducted on various mixtures and fuels. It was found that ESD sensitivity is significantly affected by particle size, while this is less so for impact and friction. Thermal testing is in progress to evaluate hazards that may be experienced during large-scale testing.

Emission current from a single micropoint of explosive emission cathode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Ping; Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024; Sun, Jun

Explosive emission cathodes (EECs) are widely used due to their large current. There has been much research on the explosive electron emission mechanism demonstrating that a current density of 10{sup 8}–10{sup 9 }A/cm{sup 2} is necessary for a micropoint to explode in several nanoseconds and the micropoint size is in micron-scale according to the observation of the cathode surface. This paper, however, makes an effort to research the current density and the micropoint size in another way which considers the space charge screening effect. Our model demonstrates that the relativistic effect is insignificant for the micropoint emission due to the smallmore » size of the micropoint and uncovers that the micron-scale size is an intrinsic demand for the micropoint to reach a space charge limited current density of 10{sup 8}–10{sup 9 }A/cm{sup 2}. Meanwhile, our analysis shows that as the voltage increases, the micropoint emission will turn from a field limited state to a space charge limited state, which makes the steady-state micropoint current density independent of the cathode work function and much less dependent on the electric field and the field enhancement factor than that predicted by the Fowler-Nordheim formula.« less

Pediatric traumatic amputations and hospital resource utilization in the United States, 2003.

PubMed

Conner, Kristen A; McKenzie, Lara B; Xiang, Huiyun; Smith, Gary A

2010-01-01

Despite the severity of consequences associated with traumatic amputation, little is known about the epidemiology or healthcare resource burden of amputation injuries, and even less is known about these injuries in the pediatric population. An analysis of patients aged < or =17 years hospitalized with traumatic amputations using the 2003 Healthcare Cost and Utilization Project Kids' Inpatient Database was performed. National estimates of amputation-associated hospitalizations, rates, resource use, and demographics were calculated. Potentially significant covariate associations were studied using hospital charges and length of stay (LOS). In 2003, 956 cases of traumatic amputations among children aged < or =17 years resulted in 21.6 million dollars (standard deviation [SD] = 2.2 million dollars) in inpatient charges and 3,967 days (SD = 354) of hospitalization in the United States. Finger and/or thumb amputations accounted for the majority of injuries (64.0%). Mean (SD) hospital charges and LOS were 23,157 dollars (49,018 dollars) and 4.1 (7.4) days, respectively. Traumatic leg amputations incurred the highest mean hospital charges (120,275 dollars) and longest mean LOS (18.5 days). Older children (15-17 years) experienced a higher hospitalization rate (1.84/100,000) than other age groups. Older age, amputation caused by a motorized vehicle, urban hospital location, children's hospital type, and longer LOS were associated with higher total charges. Amputation caused by lawn mower, motorized vehicle or explosives/fireworks, and children's hospital type were associated with longer LOS. Pediatric traumatic amputations contribute substantially to the health resource burden in the United States, resulting in 21 million dollars in inpatient charges annually. More effective interventions to prevent these costly injuries among children must be implemented.

Isolator fragmentation and explosive initiation tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickson, Peter; Rae, Philip John; Foley, Timothy J.

2016-09-19

Three tests were conducted to evaluate the effects of firing an isolator in proximity to a barrier or explosive charge. The tests with explosive were conducted without a barrier, on the basis that since any barrier will reduce the shock transmitted to the explosive, bare explosive represents the worst-case from an inadvertent initiation perspective. No reaction was observed. The shock caused by the impact of a representative plastic material on both bare and cased PBX 9501 is calculated in the worst-case, 1-D limit, and the known shock response of the HE is used to estimate minimum run-to-detonation lengths. The estimatesmore » demonstrate that even 1-D impacts would not be of concern and that, accordingly, the divergent shocks due to isolator fragment impact are of no concern as initiating stimuli.« less

Isolator fragmentation and explosive initiation tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickson, Peter; Rae, Philip John; Foley, Timothy J.

2015-09-30

Three tests were conducted to evaluate the effects of firing an isolator in proximity to a barrier or explosive charge. The tests with explosive were conducted without barrier, on the basis that since any barrier will reduce the shock transmitted to the explosive, bare explosive represents the worst-case from an inadvertent initiation perspective. No reaction was observed. The shock caused by the impact of a representative plastic material on both bare and cased PBX9501 is calculated in the worst-case, 1-D limit, and the known shock response of the HE is used to estimate minimum run-to-detonation lengths. The estimates demonstrate thatmore » even 1-D impacts would not be of concern and that, accordingly, the divergent shocks due to isolator fragment impact are of no concern as initiating stimuli.« less

Profiling Charge Complementarity and Selectivity for Binding at the Protein Surface

PubMed Central

Sulea, Traian; Purisima, Enrico O.

2003-01-01

A novel analysis and representation of the protein surface in terms of electrostatic binding complementarity and selectivity is presented. The charge optimization methodology is applied in a probe-based approach that simulates the binding process to the target protein. The molecular surface is color coded according to calculated optimal charge or according to charge selectivity, i.e., the binding cost of deviating from the optimal charge. The optimal charge profile depends on both the protein shape and charge distribution whereas the charge selectivity profile depends only on protein shape. High selectivity is concentrated in well-shaped concave pockets, whereas solvent-exposed convex regions are not charge selective. This suggests the synergy of charge and shape selectivity hot spots toward molecular selection and recognition, as well as the asymmetry of charge selectivity at the binding interface of biomolecular systems. The charge complementarity and selectivity profiles map relevant electrostatic properties in a readily interpretable way and encode information that is quite different from that visualized in the standard electrostatic potential map of unbound proteins. PMID:12719221

Safe arming system for two-explosive munitions

DOEpatents

Jaroska, Miles F.; Niven, William A.; Morrison, Jasper J.

1978-01-01

A system for safely and positively detonating high-explosive munitions, including a source of electrical signals, a split-phase square-loop transformer responsive solely to a unique series of signals from the source for charging an energy storage circuit through a voltage doubling circuit, and a spark-gap trigger for initiating discharge of the energy in the storage circuit to actuate a detonator and thereby fire the munitions.

Thermo-Gas-Dynamic Model of Afterburning in Explosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhl, A L; Ferguson, R E; Bell, J B

2003-07-27

A theoretical model of afterburning in explosions created by turbulent mixing of the detonation products from fuel-rich charges with air is described. It contains three key elements: (i) a thermodynamic-equilibrium description of the fluids (fuel, air, and products), (ii) a multi-component gas-dynamic treatment of the flow field, and (iii) a sub-grid model of molecular processes of mixing, combustion and equilibration.

Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006

USGS Publications Warehouse

Petersen, Tanja; De Angelis, Silvio; Tytgat, Guy; McNutt, Stephen R.

2006-01-01

We present and interpret acoustic waveforms associated with a sequence of large explosion events that occurred during the initial stages of the 2006 eruption of Augustine Volcano, Alaska. During January 11–28, 2006, 13 large explosion events created ash-rich plumes that reached up to 14 km a.s.l., and generated atmospheric pressure waves that were recorded on scale by a microphone located at a distance of 3.2 km from the active vent. The variety of recorded waveforms included sharp N-shaped waves with durations of a few seconds, impulsive signals followed by complex codas, and extended signals with emergent character and durations up to minutes. Peak amplitudes varied between 14 and 105 Pa; inferred acoustic energies ranged between 2×108 and 4×109 J. A simple N-shaped short-duration signal recorded on January 11, 2006 was associated with the vent-opening blast that marked the beginning of the explosive eruption sequence. During the following days, waveforms with impulsive onsets and extended codas accompanied the eruptive activity, which was characterized by explosion events that generated large ash clouds and pyroclastic flows along the flanks of the volcano. Continuous acoustic waveforms that lacked a clear onset were more common during this period. On January 28, 2006, the occurrence of four large explosion events marked the end of this explosive eruption phase at Augustine Volcano. After a transitional period of about two days, characterized by many small discrete bursts, the eruption changed into a stage of more sustained and less explosive activity accompanied by the renewed growth of a summit lava dome.

Laws of attenuation of axially symmetrical shock waves in shells of detonating extended charges

NASA Astrophysics Data System (ADS)

Kuzin, E. N.; Zagarskih, V. I.; Efanov, V. V.

2016-12-01

The procedure and algorithms are proposed for an experimental and computational estimate of attenuation of radial shock waves occurring in shells of detonating extended charges during glancing detonation of their ammunition (explosives). Based on results of experimental, the semiempirical dependence characterizing the attenuation law for such waves is obtained.

43. BUILDING NO. 454, ORDNANCE FACILITY (BAG CHARGE FILLING PLANT), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

43. BUILDING NO. 454, ORDNANCE FACILITY (BAG CHARGE FILLING PLANT), DETAIL OF EXPLOSION-PROOF ELECTRICAL SWITCH BOX (SWITCH GEAR INSIDE BOX SUBMERGED IN OIL TO QUENCH SPARKS), SWITCH EQUIPMENT MADE BY GENERAL ELECTRIC. - Picatinny Arsenal, 400 Area, Gun Bag Loading District, State Route 15 near I-80, Dover, Morris County, NJ

Explosively Driven Particle Fields Imaged Using a High-Speed Framing Camera and Particle Image Velocimetry

DTIC Science & Technology

2011-08-01

inert steel particles and by Frost et al. (2005, 2007) with reactive aluminum and magnesium particles. All used sensitized nitromethane and were...particles in a spherical or cylindrical charge case was used with sensitized nitromethane . Frost et al. (2002), determined that for a given charge

Comparison study for multiple ionization of carbonyl sulfide by linearly and circularly polarized intense femtosecond laser fields using Coulomb explosion imaging

NASA Astrophysics Data System (ADS)

Ma, Pan; Wang, Chuncheng; Luo, Sizuo; Yu, Xitao; Li, Xiaokai; Wang, Zhenzhen; Hu, Wenhui; Yu, Jiaqi; Yang, Yizhang; Tian, Xu; Cui, Zhonghua; Ding, Dajun

2018-05-01

We studied the relative yields and dissociation dynamics for two- and three-body Coulomb explosion (CE) channels from highly charged carbonyl sulfide molecules in intense laser fields using the CE imaging technique. The electron recollision contributions are evaluated by comparing the relative yields for the multiple ionization process in linearly polarized and circularly polarized (LP and CP) laser fields. The nonsequential multiple ionization is only confirmed for the charge states of 2 to 4 because the energy for further ionization from the inner orbital is much larger than the maximum recollision energy, 3.2U p . The novel deviations of kinetic energy releases distributions between LP and CP pulses are observed for the charge states higher than 4. It can be attributed to the stronger molecular bending in highly charged states before three-body CE with CP light, in which the bending wave packet is initialed by the triple or quartic ionization and spread along their potential curves. Compared to LP light, CP light ionizes a larger fraction of bending molecules in the polarization plane.

Comparing CTH Simulations and Experiments on Explosively Loaded Rings

NASA Astrophysics Data System (ADS)

Braithwaite, C. H.; Aydelotte, B.; Thadhani, N. N.; Williamson, D. M.

2011-06-01

A series of experiments were conducted on explosively loaded rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with PDV and the arrangement was imaged using a high speed camera. Both the ring material and the material used as the explosive container were altered and the results compared with simulations performed in CTH. Good agreement was found between the simulations and the experiments. The maximum radial velocity attained was approximately 450 m/s, which was achieved through loading with a 5g PETN based charge.

Characteristic overpressure-impulse-distance curves for vapour cloud explosions using the TNO Multi-Energy model.

PubMed

Díaz Alonso, Fernando; González Ferradás, Enrique; Sánchez Pérez, Juan Francisco; Miñana Aznar, Agustín; Ruiz Gimeno, José; Martínez Alonso, Jesús

2006-09-21

A number of models have been proposed to calculate overpressure and impulse from accidental industrial explosions. When the blast is produced by ignition of a vapour cloud, the TNO Multi-Energy model is widely used. From the curves given by this model, data are fitted to obtain equations showing the relationship between overpressure, impulse and distance. These equations, referred herein as characteristic curves, can be fitted by means of power equations, which depend on explosion energy and charge strength. Characteristic curves allow the determination of overpressure and impulse at each distance.

Coulomb explosion of the hot spot of micropinches

NASA Astrophysics Data System (ADS)

Oreshkin, V. I.; Oreshkin, E. V.

2017-01-01

It has been shown that the generation of hard X-ray radiation, electron beam, and high energy ions that have been detected in experiments on compressing pinches can be related to the Coulomb explosion of a micropinch hot spot, which is formed due to the outflow of the material. In the outflow process, the plasma temperature in the hot spot increases and conditions appear for the transition of electrons to the regime of continuous acceleration. The exit of runaway electrons from the hot spot region leads to the creation of a positive bulk charge, then to a Coulomb explosion. Conditions under which electrons pass to the continuous acceleration regime have been determined and estimates of the ion kinetic energy upon a Coulomb explosion have been obtained.

Textural variations and fragmentation processes in peperite formed between felsic lava flow and wet substrate: An example from the Cretaceous Buan Volcanics, southwest Korea

NASA Astrophysics Data System (ADS)

Gihm, Yong Sik; Kwon, Chang Woo

2017-02-01

Multiple exposures of peperite within the Cretaceous Buan Volcanics, southwest Korea, have been examined in order to determine variations in their textural characteristics and to investigate their mode of formation. Along undulating boundaries between rhyolite (lava flow) and deformed host sediment expressed as a series of load and flame structures, exposures commonly contain two distinct types of peperite. Type-1 peperites are composed mostly of rounded juvenile clasts at their base and polyhedral juvenile clasts at their upper levels, interpreted to have formed via a two-stage process. Firstly, abrasion of juvenile clasts occurred after their fragmentation due to shear stress imparted by the overlying and still-moving lava flow, forming rounded juvenile clasts. Subsequent in situ quenching fragmentation of the lava flow produced clasts with platy to polyhedral shapes immediately after emplacement of the lava flow. Type-2 peperites laterally extend into the interior of featureless rhyolite as layers that decrease in thickness with increasing distance away from the flame zone. These layers exhibit horizontal textural variations, ranging from poorly sorted mixtures of ash- to block-sized angular juvenile clasts in the proximal zone, to closely packed polyhedral and tabular juvenile clasts with jigsaw-crack textures in the middle and distal zones. Type-2 peperite are inferred to have formed due to internal steam explosions that resulted from an expansion of heated pore water (leading to an increase in pore fluid pressure) that had been vertically injected into the interior of the rhyolite from the flame zone. The proximal zone, composed mainly of poorly sorted mixtures of juvenile clasts, represents the explosion sites. Juvenile clasts in the middle and distal zones are interpreted to have formed due to three separate processes: the development of fractures in the rhyolite during the internal steam explosions, injection of the host sediment through the fractures, and in situ quenching fragmentation. Deformation of the host sediment exerted an important control on peperite-forming processes, with the internal steam explosions suggested to have formed the closely packed, juvenile clasts with a jigsaw-crack texture rather than the clasts that are widely dispersed.

Trends in maar crater size and shape using the global Maar Volcano Location and Shape (MaarVLS) database

NASA Astrophysics Data System (ADS)

Graettinger, A. H.

2018-05-01

A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption. Recent experimental and geophysical research has shown that crater complexity can reflect subsurface complexity. Morphometry provides a means of characterizing a global population of maar craters in order to establish the typical size and shape of features. A global database of Quaternary maar crater planform morphometry indicates that maar craters are typically not circular and frequently have compound shapes resembling overlapping circles. Maar craters occur in volcanic fields that contain both small volume and complex volcanoes. The global perspective provided by the database shows that maars are common in many volcanic and tectonic settings producing a similar diversity of size and shape within and between volcanic fields. A few exceptional populations of maars were revealed by the database, highlighting directions of future research to improve our understanding on the geometry and spacing of subsurface explosions that produce maars. These outlying populations, such as anomalously large craters (>3000 m), chains of maars, and volcanic fields composed of mostly maar craters each represent a small portion of the database, but provide opportunities to reinvestigate fundamental questions on maar formation. Maar crater morphometry can be integrated with structural, hydrological studies to investigate lateral migration of phreatomagmatic explosion location in the subsurface. A comprehensive database of intact maar morphometry is also beneficial for the hunt for maar-diatremes on other planets.

Inert gas ion thruster

NASA Technical Reports Server (NTRS)

Ramsey, W. D.

1980-01-01

Inert gas performance with three types of 12 cm diameter magnetoelectrostatic containment (MESC) ion thrusters was tested. The types tested included: (1) a hemispherical shaped discharge chamber with platinum cobalt magnets; (2) three different lengths of the hemispherical chambers with samarium cobalt magnets; and (3) three lengths of the conical shaped chambers with aluminum nickel cobalt magnets. The best argon performance was produced by a 8.0 cm long conical chamber with alnico magnets. The best xenon high mass utilization performance was obtained with the same 8.0 cm long conical thruster. The hemispherical thruster obtained 75 to 87% mass utilization at 185 to 205 eV/ion of singly charged ion equivalent beam.

Using optical techniques to measure aluminum burning in post-detonation explosive fireballs

NASA Astrophysics Data System (ADS)

Peuker, Jennifer Mott

The objectives of the current study are twofold: (1) to further the understanding of aluminum combustion in an explosive fireball, specifically where, when, and with what the aluminum is reacting; and (2) to characterize AlO emission measurements from aluminized explosive fireballs in order to determine when and how AlO emission can be used as an indicator of aluminum combustion. Experiments were completed in six different environments using four distinct aluminized charges of varying aluminum particle size---3 microm, 10 microm and 40 microm---and loading amount---20 and 50 percent by mass---to determine with what the aluminum is reacting. In addition, a charge containing 20 percent aluminum oxide (Al2O3) was used as an inert comparison. The effect of the aluminum particle location with respect to the explosive material was tested by using end-loaded charges, and by placing a layer of grease on the aluminized charge tip. Time-resolved overpressure measurements are used to determine when the aluminum is burning. Experiments employing an air-gap between the explosive charge and aluminum powder aid in determining how and when aluminum is activated and combusted in the initial blast wave and the subsequent fireball containing high pressure and high temperature detonation products. Tests in four environments show that even when AlO emission intensity is lower by 90 percent in N2 or CO2 than it is in air for a charge, it is possible to have significant---60 to 70 percent---aluminum particle oxidation. In addition, substantial AlO emission was measured in the absence of unburned aluminum---almost half of the peak AlO emission measured when unburned aluminum was present. Results show that AlO emission intensity measurements are skewed to higher AlO intensities by high transient temperatures within the first 30 micros when the peak AlO emission is usually measured. The aluminum particle location also affects the amount of AlO emission measured such that when more particles are on the fireball surface, then more AlO emission is measured. However, the end-loaded aluminum does not add to the energy output enhancement as much as the pre-loaded aluminum charges since the peak pressures and initial impulse are similar for different amounts of aluminum. A grease layer on the tip of the charge reduces the amount of AlO emission measured by 90 percent, but has the same energy output in the initial blast wave as the same charge not having a grease layer, indicating that the material at the tip of a charge changes the breakout and subsequent AlO emission production. In addition, the overpressure measurements indicate that four distinct stages of aluminum combustion exist. The first stage is the detonation and the activation of the aluminum. In the second stage the aluminum burns to enhance the blast wave which is indicated by higher peak pressures and initial impulses than a charge not containing aluminum. During the third stage, the aluminum continues to burn to increase the overpressure of the chamber. The fireball cools during the fourth stage and any aluminum oxidation does not add to the energy release. The variations in how much AlO emission is measured indicate that interpreting AlO emission measurements from explosive fireballs is not straightforward with respect to correctly determining the amount of aluminum combusted, how long the aluminum reacted, or the energy released. If aluminum is available to burn and AlO emission is measured, then the aluminum is burning---even taking into account AlO emission from the oxide layer. However, when no AlO emission is measured, it does not necessarily mean that the aluminum is not burning. When AlO emission is measured it indicates that the temperatures are high enough to sustain aluminum combustion which produces AlO, and that oxidizers are present which react to produce the AlO emission. The relative intensities for the same time frame of AlO emission measured could be indicators about the temperature or number of reactions occurring. (Abstract shortened by UMI.)

Portable Hydraulic Powerpack

NASA Technical Reports Server (NTRS)

Anderson, L. A.; Henry, R. L.; Fedor, O. H.; Owens, L. J.

1986-01-01

Rechargeable hydraulic powerpack functions as lightweight, compact source of mechanical energy. Self-contained hydraulic powerpack derives energy from solid chemical charge. Combustion of charge initiated by small hammer, and revolving feeder replaces charges expended. Combustion gases cool during expansion in turbine and not too hot for release to atmosphere. Unit has applications driving wheelchairs and operating drills, winches, and other equipment in remote areas. Also replaces electric motors and internal-combustion engines as source of power in explosive atmospheres.

Human Health and Ecological Risk Assessment for the Operation of the Explosives Waste Treatment Facility at Site 300 of the Lawrence Livermore National Laboratory Volume 1: Report of Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallegos, G; Daniels, J; Wegrecki, A

2006-04-24

This document contains the human health and ecological risk assessment for the Resource Recovery and Conservation Act (RCRA) permit renewal for the Explosives Waste Treatment Facility (EWTF). Volume 1 is the text of the risk assessment, and Volume 2 (provided on a compact disc) is the supporting modeling data. The EWTF is operated by the Lawrence Livermore National Laboratory (LLNL) at Site 300, which is located in the foothills between the cities of Livermore and Tracy, approximately 17 miles east of Livermore and 8 miles southwest of Tracy. Figure 1 is a map of the San Francisco Bay Area, showingmore » the location of Site 300 and other points of reference. One of the principal activities of Site 300 is to test what are known as ''high explosives'' for nuclear weapons. These are the highly energetic materials that provide the force to drive fissionable material to criticality. LLNL scientists develop and test the explosives and the integrated non-nuclear components in support of the United States nuclear stockpile stewardship program as well as in support of conventional weapons and the aircraft, mining, oil exploration, and construction industries. Many Site 300 facilities are used in support of high explosives research. Some facilities are used in the chemical formulation of explosives; others are locations where explosive charges are mechanically pressed; others are locations where the materials are inspected radiographically for such defects as cracks and voids. Finally, some facilities are locations where the machined charges are assembled before they are sent to the on-site test firing facilities, and additional facilities are locations where materials are stored. Wastes generated from high-explosives research are treated by open burning (OB) and open detonation (OD). OB and OD treatments are necessary because they are the safest methods for treating explosives wastes generated at these facilities, and they eliminate the requirement for further handling and transportation that would be required if the wastes were treated off site.« less

Human Health and Ecological Risk Assessment for the Operation of the Explosives Waste Treatment Facility at Site 300 of the Lawrence Livermore National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallegos, G; Daniels, J; Wegrecki, A

2007-10-01

This document contains the human health and ecological risk assessment for the Resource Recovery and Conservation Act (RCRA) permit renewal for the Explosives Waste Treatment Facility (EWTF). Volume 1 is the text of the risk assessment, and Volume 2 (provided on a compact disc) is the supporting modeling data. The EWTF is operated by the Lawrence Livermore National Laboratory (LLNL) at Site 300, which is located in the foothills between the cities of Livermore and Tracy, approximately 17 miles east of Livermore and 8 miles southwest of Tracy. Figure 1 is a map of the San Francisco Bay Area, showingmore » the location of Site 300 and other points of reference. One of the principal activities of Site 300 is to test what are known as 'high explosives' for nuclear weapons. These are the highly energetic materials that provide the force to drive fissionable material to criticality. LLNL scientists develop and test the explosives and the integrated non-nuclear components in support of the United States nuclear stockpile stewardship program as well as in support of conventional weapons and the aircraft, mining, oil exploration, and construction industries. Many Site 300 facilities are used in support of high explosives research. Some facilities are used in the chemical formulation of explosives; others are locations where explosive charges are mechanically pressed; others are locations where the materials are inspected radiographically for such defects as cracks and voids. Finally, some facilities are locations where the machined charges are assembled before they are sent to the onsite test firing facilities, and additional facilities are locations where materials are stored. Wastes generated from high-explosives research are treated by open burning (OB) and open detonation (OD). OB and OD treatments are necessary because they are the safest methods for treating explosives wastes generated at these facilities, and they eliminate the requirement for further handling and transportation that would be required if the wastes were treated off site.« less

On high explosive launching of projectiles for shock physics experiments

NASA Astrophysics Data System (ADS)

Swift, Damian C.; Forest, Charles A.; Clark, David A.; Buttler, William T.; Marr-Lyon, Mark; Rightley, Paul

2007-06-01

The hydrodynamic operation of the "Forest Flyer" type of explosive launching system for shock physics projectiles was investigated in detail using one and two dimensional continuum dynamics simulations. The simulations were numerically converged and insensitive to uncertainties in the material properties; they reproduced the speed of the projectile and the shape of its rear surface. The most commonly used variant, with an Al alloy case, was predicted to produce a slightly curved projectile, subjected to some shock heating and likely exhibiting some porosity from tensile damage. The curvature is caused by a shock reflected from the case; tensile damage is caused by the interaction of the Taylor wave pressure profile from the detonation wave with the free surface of the projectile. The simulations gave only an indication of tensile damage in the projectile, as damage is not understood well enough for predictions in this loading regime. The flatness can be improved by using a case of lower shock impedance, such as polymethyl methacrylate. High-impedance cases, including Al alloys but with denser materials improving the launching efficiency, can be used if designed according to the physics of oblique shock reflection, which indicates an appropriate case taper for any combination of explosive and case material. The tensile stress induced in the projectile depends on the relative thickness of the explosive, expansion gap, and projectile. The thinner the projectile with respect to the explosive, the smaller the tensile stress. Thus if the explosive is initiated with a plane wave lens, the tensile stress is lower than that for initiation with multiple detonators over a plane. The previous plane wave lens designs did, however, induce a tensile stress close to the spall strength of the projectile. The tensile stress can be reduced by changes in the component thicknesses. Experiments verifying the operation of explosively launched projectiles should attempt to measure porosity induced in the projectile: arrival time measurements are likely to be insensitive to porous regions caused by damaged or recollected material.

SR90, strontium shaped-charge critical ionization velocity experiment

NASA Technical Reports Server (NTRS)

Wescott, Eugene M.; Stenbaek-Nielsen, Hans; Swift, Daniel W.; Valenzuela, Arnoldo; Rees, David

1990-01-01

In May 1986 an experiment was performed to test Alfven's critical ionization velocity (CIV) effect in free space, using the first high explosive shaped charge with a conical liner of strontium metal. The release, made at 540 km altitude at dawn twilight, was aimed at 48 deg to B. The background electron density was 1.5 x 10(exp 4) cu cm. A faint field-aligned Sr(+) ion streak with tip velocity of 2.6 km/s was observed from two optical sites. Using two calibration methods, it was calculated that between 4.5 x 10(exp 20) and 2 x 10(exp 21) ions were visible. An ionization time constant of 1920 s was calculated for Sr from the solar UV spectrum and ionization cross section which combined with a computer simulation of the injection predicts 1.7 x 10(exp 21) solar UV ions in the low-velocity part of the ion streak. Thus all the observed ions are from solar UV ionization of the slow (less than critical) velocity portion of the neutral jet. The observed neutral Sr velocity distribution and computer simulations indicate that 2 x 10(exp 21) solar UV ions would have been created from the fast (greater than critical) part of the jet. They would have been more diffuse, and were not observed. Using this fact it was estimated that any CIV ions created were less than 10(exp 21). It was concluded that future Sr CIV free space experiments should be conducted below the UV shadow height and in much larger background plasma density.

The nature and role of trap states in a dendrimer-based organic field-effect transistor explosive sensor

NASA Astrophysics Data System (ADS)

Tang, Guoqiang; Chen, Simon S. Y.; Lee, Kwan H.; Pivrikas, Almantas; Aljada, Muhsen; Burn, Paul L.; Meredith, Paul; Shaw, Paul E.

2013-06-01

We report the fabrication and charge transport characterization of carbazole dendrimer-based organic field-effect transistors (OFETs) for the sensing of explosive vapors. After exposure to para-nitrotoluene (pNT) vapor, the OFET channel carrier mobility decreases due to trapping induced by the absorbed pNT. The influence of trap states on transport in devices before and after exposure to pNT vapor has been determined using temperature-dependent measurements of the field-effect mobility. These data clearly show that the absorption of pNT vapor into the dendrimer active layer results in the formation of additional trap states. Such states inhibit charge transport by decreasing the density of conducting states.

Explosives remain preferred methods for platform abandonment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pulsipher, A.; Daniel, W. IV; Kiesler, J.E.

1996-05-06

Economics and safety concerns indicate that methods involving explosives remain the most practical and cost-effective means for abandoning oil and gas structures in the Gulf of Mexico. A decade has passed since 51 dead sea turtles, many endangered Kemp`s Ridleys, washed ashore on the Texas coast shortly after explosives helped remove several offshore platforms. Although no relationship between the explosions and the dead turtles was ever established, in response to widespread public concern, the US Minerals Management Service (MMS) and National Marine Fisheries Service (NMFS) implemented regulations limiting the size and timing of explosive charges. Also, more importantly, they requiredmore » that operators pay for observers to survey waters surrounding platforms scheduled for removal for 48 hr before any detonations. If observers spot sea turtles or marine mammals within the danger zone, the platform abandonment is delayed until the turtles leave or are removed. However, concern about the effects of explosives on marine life remains.« less

Design and manufacture of a D-shape coil-based toroid-type HTS DC reactor using 2nd generation HTS wire

NASA Astrophysics Data System (ADS)

Kim, Kwangmin; Go, Byeong-Soo; Sung, Hae-Jin; Park, Hea-chul; Kim, Seokho; Lee, Sangjin; Jin, Yoon-Su; Oh, Yunsang; Park, Minwon; Yu, In-Keun

2014-09-01

This paper describes the design specifications and performance of a real toroid-type high temperature superconducting (HTS) DC reactor. The HTS DC reactor was designed using 2G HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The target inductance of the HTS DC reactor was 400 mH. The expected operating temperature was under 20 K. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. Performances of the toroid-type HTS DC reactor were analyzed through experiments conducted under the steady-state and charge conditions. The fundamental design specifications and the data obtained from this research will be applied to the design of a commercial-type HTS DC reactor.

A supramolecular Tröger's base derived coordination zinc polymer for fluorescent sensing of phenolic-nitroaromatic explosives in water.

PubMed

Shanmugaraju, Sankarasekaran; Dabadie, Charlyne; Byrne, Kevin; Savyasachi, Aramballi J; Umadevi, Deivasigamani; Schmitt, Wolfgang; Kitchen, Jonathan A; Gunnlaugsson, Thorfinnur

2017-02-01

A V-Shaped 4-amino-1,8-napthalimide derived tetracarboxylic acid linker ( L ; bis-[ N -(1,3-benzenedicarboxylic acid)]-9,18-methano-1,8-naphthalimide-[ b , f ][1,5]diazocine) comprising the Tröger's base (TB) structural motif was rationally designed and synthesised to access a nitrogen-rich fluorescent supramolecular coordination polymer. By adopting the straight forward precipitation method, a new luminescent nanoscale Zn(ii) coordination polymer ( TB-Zn-CP ) was synthesized in quantitative yield using Zn(OAc) 2 ·2H 2 O and tetraacid linker L (1 : 0.5) in DMF at room temperature. The phase-purity of as-synthesised TB-Zn-CP was confirmed by X-ray powder diffraction analysis, infra-red spectroscopy, and elemental analysis. Thermogravimetric analysis suggests that TB-Zn-CP is thermally stable up to 330 °C and the morphological features of TB-Zn-CP was analysed by SEM and AFM techniques. The N 2 adsorption isotherm of thermally activated TB-Zn-CP at 77 K revealed a type-II reversible adsorption isotherm and the calculated Brunauer-Emmett-Teller (BET) surface area was found to be 72 m 2 g -1 . Furthermore, TB-Zn-CP displayed an excellent CO 2 uptake capacity of 76 mg g -1 at 273 K and good adsorption selectivity for CO 2 over N 2 and H 2 . The aqueous suspension of as-synthesized TB-Zn-CP showed strong green fluorescence ( λ max = 520 nm) characteristics due to the internal-charge transfer (ICT) transition and was used as a fluorescent sensor for the discriminative sensing of nitroaromatic explosives. The aqueous suspension of TB-Zn-CP showed the largest quenching responses with high selectivity for phenolic-nitroaromatics (4-NP, 2,4-DNP and PA) even in the concurrent presence of other potentially competing nitroaromatic analytes. The fluorescence titration studies also provide evidence that TB-Zn-CP detects picric acid as low as the parts per billion (26.3 ppb) range. Furthermore, the observed fluorescence quenching responses of TB-Zn-CP towards picric acid were highly reversible. The highly selective fluorescence quenching responses including the reversible detection efficiency make the nanoscale coordination polymer TB-Zn-CP a potential material for the discriminative fluorescent sensing of nitroaromatic explosives.

Time-dependent buoyant puff model for explosive sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kansa, E.J.

1997-01-01

Several models exist to predict the time dependent behavior of bouyant puffs that result from explosions. This paper presents a new model that is derived from the strong conservative form of the conservation partial differential equations that are integrated over space to yield a coupled system of time dependent nonlinear ordinary differential equations. This model permits the cloud to evolve from an intial spherical shape not an ellipsoidal shape. It ignores the Boussinesq approximation, and treats the turbulence that is generated by the puff itself and the ambient atmospheric tubulence as separate mechanisms in determining the puff history. The puffmore » cloud rise history was found to depend no only on the mass and initial temperature of the explosion, but also upon the stability conditions of the ambient atmosphere. This model was calibrated by comparison with the Roller Coaster experiments.« less

Studies on the detection and identification of the explosives in the terahertz range

NASA Astrophysics Data System (ADS)

Zhou, Qing-li; Zhang, Cun-lin; Li, Wei-Wei; Mu, Kai-jun; Feng, Rui-shu

2008-03-01

The sensing of the explosives and the related compounds is very important for homeland security and defense. Based on the non-invasive terahertz (THz) technology, we have studied some pure and mixed explosives by using the THz time-domain spectroscopy and have obtained the absorption spectra of those samples. The obtained results show that those explosives can be identified due to their different characterized finger-prints in the terahertz frequency region of 0.2-2.5 THz. Furthermore, the spectra analyses indicate that the shape and peak positions of the spectra for these mixed explosive are mainly determined by their explosive components. In order to identify those different kinds of explosives, we have applied the artificial neural network, which is a mathematical device for modeling complex and non-linear functionalities, to our present work. After the repetitive modeling and adequate training with the known input-output data, the identification of the explosive is realized roughly on a multi-hidden-layers model. It is shown that the neural network analyses of the THz spectra would positively identify the explosives and reduce false alarm rates.

Shock Initiated Reactions of Reactive Multiphase Blast Explosives

NASA Astrophysics Data System (ADS)

Wilson, Dennis; Granier, John; Johnson, Richard; Littrell, Donald

2015-06-01

This paper describes a new class of reactive multiphase blast explosives (RMBX) and characterization of their blast characteristics. These RMBXs are non-ideal explosive compositions of perfluoropolyether (PFPE), nano aluminum, and a micron-size high-density reactive metal - Tantalum, Zirconium, or Zinc in mass loadings of 66 to 83 percent. Unlike high explosives, these PFPE-metal compositions release energy via a fast self-oxidized combustion wave (rather than a true self-sustaining detonation) that is shock dependent, and can be overdriven to control energy release rate. The term ``reactive multiphase blast'' refers to the post-dispersion blast behavior: multiphase in that there are a gas phase that imparts pressure and a solid (particulate) phase that imparts momentum; and reactive in that the hot metal particles react with atmospheric oxygen and the explosive gas products to give an extended pressure pulse. The RMBX formulations were tested in two spherical core-shell geometries - an RMBX shell exploded by a high explosive core, and an RMBX core imploded by a high explosive shell. The fireball and blast characteristics were compared to a C-4 baseline charge.

EDS V25 containment vessel explosive qualification test report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudolphi, John Joseph

2012-04-01

The V25 containment vessel was procured by the Project Manager, Non-Stockpile Chemical Materiel (PMNSCM) as a replacement vessel for use on the P2 Explosive Destruction Systems. It is the first EDS vessel to be fabricated under Code Case 2564 of the ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels. The explosive rating for the vessel based on the Code Case is nine (9) pounds TNT-equivalent for up to 637 detonations. This limit is an increase from the 4.8 pounds TNT-equivalency rating for previous vessels. This report describes the explosive qualification tests thatmore » were performed in the vessel as part of the process for qualifying the vessel for explosive use. The tests consisted of a 11.25 pound TNT equivalent bare charge detonation followed by a 9 pound TNT equivalent detonation.« less

Detonation initiation of heterogeneous melt-cast high explosives

NASA Astrophysics Data System (ADS)

Chuzeville, V.; Baudin, G.; Lefrançois, A.; Genetier, M.; Barbarin, Y.; Jacquet, L.; Lhopitault, J.-L.; Peix, J.; Boulanger, R.; Catoire, L.

2017-01-01

2,4,6-trinitrotoluene (TNT) is widely used in conventional and insensitive munitions as a fusible binder, commonly melt-cast with other explosives such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) or 3-nitro-1,2,4-triazol-one (NTO). In this paper, we study the shock-to-detonation transition phenomenon in two melt-cast high explosives (HE). We have performed plate impact tests on wedge samples to measure run-distance and time-to-detonation in order to establish the Pop-plot relation for several melt-cast HE. Highlighting the existence of the single curve buildup, we propose a two phase model based on a Zeldovich, Von-Neumann, Döring (ZND) approach where the deflagration fronts grow from the explosive grain boundaries. Knowing the grain size distribution, we calculate the deflagration velocities of the explosive charges as a function of shock pressure and explore the possible grain fragmentation.

Pyroclast acceleration and energy partitioning in fake explosive eruptions

NASA Astrophysics Data System (ADS)

Gaudin, Damien; Taddeucci, Jacopo; Scheu, Bettina; Valentine, Greg; Capponi, Antonio; Kueppers, Ulrich; Graettiger, Allison; Sonder, Ingo

2014-05-01

Explosive eruptions are characterized by the fast release of energy, with gas expansion playing a lead role. An excess of pressure may be generated either by the exsolution and accumulation of volatiles (e.g., vulcanian and strombolian explosions) or by in situ vaporization of water (e.g., phreato-magmatic explosions). The release of pressurized gas ejects magma and country rock pyroclasts at velocities that can reach several hundred of meters per second. The amount and velocity of pyroclasts is determined not only by the total released energy, but also by the system-specific dynamics of the energy transfer from gas to pyroclasts. In this context, analogue experiments are crucial, since the amount of available energy is determined. Here, we analyze three different experiments, designed to reproduce different aspects of explosive volcanism, focusing on the acceleration phase of the pyroclasts, in order to compare how the potential energy is transferred to the pyroclasts in different systems. In the first, shock-tube-type experiment, salt crystals resting in a pressurized Plexiglas cylinder are accelerated when a diaphragm set is suddenly opened, releasing the gas. In the second experiment, a pressurized air bubble is released in a water-filled Plexiglas pipe; diaphragm opening causes sudden expansion and bursting of the bubble and ejection of water droplets. In the last experiment, specifically focusing on phreatomagmatic eruptions, buried explosive charges accelerate the overlying loose material. All experiments were monitored by multiple high speed cameras and a variety of sensors. Despite the largely differing settings and processes, particle ejection velocity above the vent from the three experiments share a non-linear decay over time. Fitting this decay allows to estimate a characteristic depth that is related to the specific acceleration processes. Given that the initial available energy is experimentally controlled a priori, the information on the acceleration processes (and related kinetic energy) can be used to brings new constraints on the energy partition and general pyroclasts ejection mechanisms during eruptions.

Analysis and Simulation of Near-Field Ground Motions from the Source Physics Experiment

NASA Astrophysics Data System (ADS)

Antoun, T. H.; Vorobiev, O.; Xu, H.; Herbold, E. B.; Glenn, L.; Lomov, I.

2011-12-01

The Source Physics Experiment (SPE) at the Nevada National Security Site is planned as a series of chemical explosions under a variety of emplacement conditions. The goal of the SPE is to improve our physical understanding and ability to model explosively generated seismic waves, particularly S-waves. The first SPE explosion (SPE1) consisted of a 100 kg shot at a depth of 60 meters in granite (Climax Stock). The shot was well-recorded by an array of over 150 instruments, including both near-field wave motion measurements as well as far-field seismic measurements. This paper focuses on measurements and modeling of the near-field data, which included triaxial acceleration measurements at eighteen different locations azimuthally distributed around the explosive charge. Three triaxial accelerometers were embedded in each of six vertical boreholes, distributed in two concentric rings around the charge. The inner ring consisted of three equidistant boreholes at a radius of 10 m from the charge, and the outer ring consisted of another three equidistant boreholes at a radius of 20 m. In each borehole, the accelerometers were vertically distributed at depths of 60 m (shot horizon), 50 m and 15 m. Surface accelerations were also recorded along a radial line centered at surface ground zero. A review of the SPE1 data shows that the peak radial velocity as a function of scaled range is consistent with previous nuclear explosion data but exhibits greater variability. The scaled peak radial displacement also exhibits greater variability but the mean values are significantly higher than exhibited in previous nuclear explosion data. These higher displacements were also observed in calculations performed with a constitutive model based on nuclear explosion data in hard rock, but employed a JWL equation of state for the ANFO explosive used in SPE1. The reason for this behavior is believed to be the higher effective ratio of specific heats in the explosion products of the chemical explosive, leading to higher residual cavity pressure. Azimuthal scatter in the velocity data correspond to joint orientation, and as anticipated, the joints appear to be the principal source of observed shear wave generation in the near field. Preliminary modeling of the SPE1 data shows that continuum simulations that do not explicitly account for the effect of joints will not successfully reproduce the observed directional variations in the recorded data. However, 2D and 3D simulations that explicitly account for joints and pre-existing fractures show that a low friction angle, derived with water-filled joints, may account for the observed variation in peak velocity and displacement. Waves appear to propagate more readily in the direction of persistent joints, as opposed to staggered joints. Furthermore, the anisotropy associated with wave propagation seems to be more pronounced when the friction angle was lowered to account for the effect of saturation. Further modeling is being conducted with continued focus on the effect of the presence of joints and their properties on shear wave generation. Simulation results will be compared to experimental measurements of both radial and non-radial motions from the SPE1 event, as well as from planned future SPE explosions.

23. BUILDING NO. 452, ORDNANCE FACILITY (BAG CHARGE FILLING PLANT), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. BUILDING NO. 452, ORDNANCE FACILITY (BAG CHARGE FILLING PLANT), INTERIOR, LOOKING SOUTH DOWN CENTRAL CORRIDOR. NOTE BINS IN WALLS ON EITHER SIDE OF CORRIDOR, USED FOR PASSING EXPLOSIVES AND LOADED ITEMS TO SIEVING ROOMS BEYOND WALLS. - Picatinny Arsenal, 400 Area, Gun Bag Loading District, State Route 15 near I-80, Dover, Morris County, NJ

Two dimensional numerical prediction of deflagration-to-detonation transition in porous energetic materials.

PubMed

Narin, B; Ozyörük, Y; Ulas, A

2014-05-30

This paper describes a two-dimensional code developed for analyzing two-phase deflagration-to-detonation transition (DDT) phenomenon in granular, energetic, solid, explosive ingredients. The two-dimensional model is constructed in full two-phase, and based on a highly coupled system of partial differential equations involving basic flow conservation equations and some constitutive relations borrowed from some one-dimensional studies that appeared in open literature. The whole system is solved using an optimized high-order accurate, explicit, central-difference scheme with selective-filtering/shock capturing (SF-SC) technique, to augment central-diffencing and prevent excessive dispersion. The sources of the equations describing particle-gas interactions in terms of momentum and energy transfers make the equation system quite stiff, and hence its explicit integration difficult. To ease the difficulties, a time-split approach is used allowing higher time steps. In the paper, the physical model for the sources of the equation system is given for a typical explosive, and several numerical calculations are carried out to assess the developed code. Microscale intergranular and/or intragranular effects including pore collapse, sublimation, pyrolysis, etc. are not taken into account for ignition and growth, and a basic temperature switch is applied in calculations to control ignition in the explosive domain. Results for one-dimensional DDT phenomenon are in good agreement with experimental and computational results available in literature. A typical shaped-charge wave-shaper case study is also performed to test the two-dimensional features of the code and it is observed that results are in good agreement with those of commercial software. Copyright © 2014 Elsevier B.V. All rights reserved.

30 CFR 57.8520 - Ventilation plan.

Code of Federal Regulations, 2010 CFR

2010-07-01

... mine openings adjacent to the mine; (9) Locations of permanent underground shops, diesel fuel storage depots, oil fuel storage depots, hoist rooms, compressors, battery charging stations and explosive...

Longitudinal bunch shaping of picosecond high-charge MeV electron beams

DOE PAGES

Beaudoin, B. L.; Thangaraj, J. C. T.; Edstrom, Jr., D.; ...

2016-10-20

With ever increasing demands for intensities in modern accelerators, the understanding of space-charge effects becomes crucial. Herein are presented measurements of optically shaped picosecond-long electron beams in a superconducting L-band linac over a wide range of charges, from 0.2 nC to 3.4 nC. At low charges, the shape of the electron beam is preserved, while at higher charge densities, modulations on the beam convert to energy modulations. Here, energy profile measurements using a spectrometer and time profile measurements using a streak camera reveal the dynamics of longitudinal space-charge on MeV-scale electron beams.

Detonation charge size versus coda magnitude relations in California and Nevada

USGS Publications Warehouse

Brocher, T.M.

2003-01-01

Magnitude-charge size relations have important uses in forensic seismology and are used in Comprehensive Nuclear-Test-Ban Treaty monitoring. I derive empirical magnitude versus detonation-charge-size relationships for 322 detonations located by permanent seismic networks in California and Nevada. These detonations, used in 41 different seismic refraction or network calibration experiments, ranged in yield (charge size) between 25 and 106 kg; coda magnitudes reported for them ranged from 0.5 to 3.9. Almost all represent simultaneous (single-fired) detonations of one or more boreholes. Repeated detonations at the same shotpoint suggest that the reported coda magnitudes are repeatable, on average, to within 0.1 magnitude unit. An empirical linear regression for these 322 detonations yields M = 0.31 + 0.50 log10(weight [kg]). The detonations compiled here demonstrate that the Khalturin et al. (1998) relationship, developed mainly for data from large chemical explosions but which fits data from nuclear blasts, can be used to estimate the minimum charge size for coda magnitudes between 0.5 and 3.9. Drilling, loading, and shooting logs indicate that the explosive specification, loading method, and effectiveness of tamp are the primary factors determining the efficiency of a detonation. These records indicate that locating a detonation within the water table is neither a necessary nor sufficient condition for an efficient shot.

Photophysics of detection of explosive vapours via luminescence quenching of thin films: impact of inter-molecular interactions.

PubMed

Shoaee, Safa; Fan, Shengqiang; Burn, Paul L; Shaw, Paul E

2016-09-21

Fluorescence-based detection of explosive analytes requires an understanding of the nature of the excited state responsible for the luminescence response of a sensing material. Many measurements are carried out to elucidate the fundamental photophysical properties of an emissive material in solution. However, simple transfer of the understanding gained from the solution measurements to the solid-state can lead to errors. This is in part due to the absence of inter-molecular interactions of the chromophores in solution, which are present in the solid-state. To understand the role of inter-molecular interactions on the detection of explosive analytes we have chosen dendrimers from two different families, D1 and D2, which allow facile control of the inter-molecular interactions through the choice of dendrons and emissive chromophores. Using ultrafast transient absorption spectroscopy we find that the solution photoinduced absorption (PA) for both materials can be explained in terms of the generation of singlet excitons, which decay to the ground state, or intersystem cross (ISC) to form a triplet exciton. In neat films however, we observe different photophysical behaviours; first, ISC to the triplet state does not occur, and second, depending on the chromophore, charge transfer and charge separated states are formed. Furthermore, we find that when either dendrimer is interfaced with analyte vapour, the singlet state is strongly quenched, generating a charge transfer state that undergoes geminate recombination.

Numerical Simulation of Pre-heated Confined PBX Charge Under Low Velocity

NASA Astrophysics Data System (ADS)

Hu, Cai; Wu, Yanqing; Huang, Fenglei; Liu, Yan; Explosion; damage Team

2017-06-01

Impact sensitivity and thermal safety are very important for explosive safety usage.To investigate the effect of thermal softening on impact sensitivity of HMX-based PBX, a finite element model aiming at pre-heated confined PBX charge sbujected to bullets impact has been established. The predicted ignition starting area of the explosive charge was evaluated based on volume strain and equivalent strain contours. It showed that the ignition starting area moves towards the center of the explosives from the surface with increase of heating temperature. The threshold velocity does not increase monotonically with the pre-heating temperature increases. Instead, the threshold velocity rises till 360 m/s when the cook-off temperature is lower than 75°, then decreases the increased temperature. The results imply that our PBX has the lowest impact sensitivity at about 75°. These numerical results agree very well with the corresponding experiment results conducted by Dai et al. The influence of thermal softening on the impact sensitivity has been analyzed. As the strength decreases, more impact energy will be absorbed. At the same time, shear resistance ability will be weaken and volume compression work may play a more important role to ignition. China National Nature Science Foundation (11572045), ``Science Challenging Program'' (JCKY2016212A501), opening fund from Safety ammunition research and Development Center (RMC2015B03).

Far Field Boundary Conditions for Underwater Explosions

DTIC Science & Technology

1994-12-22

NSWCDDfTR-94/20 CHAPTER 1 INTRODUCTION A factor controlling the computational resources required to model an underwater explo- sion is the extent of...NSWCDD/TRI-94/20 SPHERICAL SHOCKS The explosion of a spherical TNT charge in a uniform water environment is modeled in spherical coordinates. The TNT is...described using a JWL equation of state while the water is modeled using a modified Tait equation of state.6 The TNT is assumed to combust

Design and Testing of the ARL Squeeze 4 Helical Flux Compression Generator

DTIC Science & Technology

2013-06-01

armature makes contact. Centering the armature inside the coil was accomplished with three machined polyurethane (4 lb/ft3 Lastafoam)3 foam rings. A...after shrinking was ~1 mm thick. The explosive charge was comprised of a paper- reinforced phenolic cylinder filled with Comp-B explosive fill. The...backfilled with polyester resin. Foam rubber was placed between coil windings (figure 3a). All other subsequent experiments used a custom rapid-prototyped

Preparation of graphene by electrical explosion of graphite sticks.

PubMed

Gao, Xin; Xu, Chunxiao; Yin, Hao; Wang, Xiaoguang; Song, Qiuzhi; Chen, Pengwan

2017-08-03

Graphene nanosheets were produced by electrical explosion of high-purity graphite sticks in distilled water at room temperature. The as-prepared samples were characterized by various techniques to find different forms of carbon phases, including graphite nanosheets, few-layer graphene, and especially, mono-layer graphene with good crystallinity. Delicate control of energy injection is critical for graphene nanosheet formation, whereas mono-layer graphene was produced under the charging voltage of 22.5-23.5 kV. On the basis of electrical wire explosion and our experimental results, the underlying mechanism that governs the graphene generation was carefully illustrated. This work provides a simple but innovative route for producing graphene nanosheets.

Comparing CTH simulations and experiments on explosively loaded rings

NASA Astrophysics Data System (ADS)

Braithwaite, C. H.; Aydelotte, Brady; Collins, Adam; Thadhani, Naresh; Williamson, David Martin

2012-03-01

A series of experiments were conducted on explosively loaded metallic rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with photon Doppler velocimetry (PDV) and the arrangement was imaged using high speed photography. Both the ring material and the material used as the explosive container were altered and the results compared with simulations performed in CTH. Good agreement was found between the simulations and the experiments. The maximum radial velocity attained was approximately 380 m/s, which was achieved through loading with a 5g PETN based charge.

Comparison of Explosives Residues from the Blow-in-Place Detonation of 155-mm High-Explosive Projectiles

DTIC Science & Technology

2006-06-01

were M107 high-explosive deep-cavity 155-mm howitzer projectiles with a supplemental charge and an M739 point- detonating fuze mounted in the nose...M107, HE, w/o fuze IOP03E100-011 14 1390010809447 N340 Fuze, point-detonating, M739 MA-84B007-013 14 1375014151232 ML47 Cap, blasting, non-electric 30... M739 N340 0 21 0 ə Cap, blasting, M11 ML47 ə 27 ə ə Cap, blasting, M13 MN03 0 ə 0 ə Cap, blasting, M14 MN06 0 0 0 ə Cord, detonating M456 0

Shock initiation of explosives: High temperature hot spots explained

NASA Astrophysics Data System (ADS)

Bassett, Will P.; Johnson, Belinda P.; Neelakantan, Nitin K.; Suslick, Kenneth S.; Dlott, Dana D.

2017-08-01

We investigated the shock initiation of energetic materials with a tabletop apparatus that uses km s-1 laser-driven flyer plates to initiate tiny explosive charges and obtains complete temperature histories with a high dynamic range. By comparing various microstructured formulations, including a pentaerythritol tetranitrate (PETN) based plastic explosive (PBX) denoted XTX-8003, we determined that micron-scale pores were needed to create high hot spot temperatures. In charges where micropores (i.e., micron-sized pores) were present, a hot spot temperature of 6000 K was observed; when the micropores were pre-compressed to nm scale, however, the hot spot temperature dropped to ˜4000 K. By comparing XTX-8003 with an analog that replaced PETN by nonvolatile silica, we showed that the high temperatures require gas in the pores, that the high temperatures were created by adiabatic gas compression, and that the temperatures observed can be controlled by the choice of ambient gases. The hot spots persist in shock-compressed PBXs even in vacuum because the initially empty pores became filled with gas created in-situ by shock-induced chemical decomposition.

Source spectral variation and yield estimation for small, near-source explosions

NASA Astrophysics Data System (ADS)

Yoo, S.; Mayeda, K. M.

2012-12-01

Significant S-wave generation is always observed from explosion sources which can lead to difficulty in discriminating explosions from natural earthquakes. While there are numerous S-wave generation mechanisms that are currently the topic of significant research, the mechanisms all remain controversial and appear to be dependent upon the near-source emplacement conditions of that particular explosion. To better understand the generation and partitioning of the P and S waves from explosion sources and to enhance the identification and discrimination capability of explosions, we investigate near-source explosion data sets from the 2008 New England Damage Experiment (NEDE), the Humble-Redwood (HR) series of explosions, and a Massachusetts quarry explosion experiment. We estimate source spectra and characteristic source parameters using moment tensor inversions, direct P and S waves multi-taper analysis, and improved coda spectral analysis using high quality waveform records from explosions from a variety of emplacement conditions (e.g., slow/fast burning explosive, fully tamped, partially tamped, single/ripple-fired, and below/above ground explosions). The results from direct and coda waves are compared to theoretical explosion source model predictions. These well-instrumented experiments provide us with excellent data from which to document the characteristic spectral shape, relative partitioning between P and S-waves, and amplitude/yield dependence as a function of HOB/DOB. The final goal of this study is to populate a comprehensive seismic source reference database for small yield explosions based on the results and to improve nuclear explosion monitoring capability.

Rare-gas-cluster explosions under irradiation by intense short XUV pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffmann, K.; Murphy, B.; Kandadai, N.

High-intensity, extreme-ultraviolet (XUV) femtosecond interactions with large rare-gas clusters of xenon and argon have been studied at a wavelength of 38 nm. Pulses of XUV radiation with nJ energy are produced by high-order harmonic conversion from a 35-fs, near-infrared, terawatt laser. Mass resolved ion spectra show charge states up to Xe{sup 8+} and Ar{sup 4+}. Kinetic-energy measurements of ions and electrons indicate that a nanoplasma is formed and a hydrodynamic cluster explosion ensues after heating by the short wavelength pulse. It appears that the observed charge states and electron temperatures are consistent with sequential, single-photon ionization and collisional ionization ofmore » ions that have had their ionization potential depressed by plasma continuum lowering in the cluster nanoplasma.« less

Explosion safety in industrial electrostatics

NASA Astrophysics Data System (ADS)

Szabó, S. V.; Kiss, I.; Berta, I.

2011-01-01

Complicated industrial systems are often endangered by electrostatic hazards, both from atmospheric (lightning phenomenon, primary and secondary lightning protection) and industrial (technological problems caused by static charging and fire and explosion hazards.) According to the classical approach protective methods have to be used in order to remove electrostatic charging and to avoid damages, however no attempt to compute the risk before and after applying the protective method is made, relying instead on well-educated and practiced expertise. The Budapest School of Electrostatics - in close cooperation with industrial partners - develops new suitable solutions for probability based decision support (Static Control Up-to-date Technology, SCOUT) using soft computing methods. This new approach can be used to assess and audit existing systems and - using the predictive power of the models - to design and plan activities in industrial electrostatics.

Induced polarization: Simulation and inversion of nonlinear mineral electrodics

NASA Astrophysics Data System (ADS)

Agunloye, Olu

1983-02-01

Graph-theoretic representations are used to model nonlinear electrodics, while forward and inverse simulations are based on reaction rate theory. The electrodic responses are presented as distorted elliptical Lissajous shapes obtained from dynamic impedance over a full cycle. Simulations show that asymmetry in reaction energy barrier causes slight asymmetry in the shape of the response ellipse and hardly affects the phase angle of the complex electrode impedance. The charge transfer resistance and the diffusion constraints tend to have opposite effects. The former causes reduction in the phase angle, tending to make the impedance purely resistive. Both of these mechanisms show saturation effects. Charge transfer resistance at its limit forces a thin S-type symmetry on the Lissajous patterns, while with diffusion control the size of the Lissajous patterns begins to reduce after saturation. The fixed layer causes substantial increase in the phase angle and tends to “enlarge” the Lissajous patterns. It is responsible for the hysteresis-like shapes of the Lissajous patterns when superimposed on strong charge transfer resistance. This study shows that it is quite possible to deduce the mechanisms that control the electrodic processes by inverting electrodic parameters from “observed” distorted, nonelliptical Lissajous patterns characteristic of nonlinear electrodics. The results and qualities of the inversion technique are discussed.

Generation of ultra-fast cumulative water jets by sub-microsecond underwater electrical explosion of conical wire arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shafer, D.; Gurovich, V. Tz.; Gleizer, S.

The results of experiments with underwater electrical explosion of modified conical arrays of copper and aluminum wires are presented. A pulsed generator producing a 550 kA-amplitude current with a 400 ns rise time was used in the explosion of the arrays. The array explosion generates water flows converging at the axis of the cone. This flow generates a fast-moving water jet with a velocity exceeding 1.8 × 10{sup 5 }cm/s, which was observed being ejected from the surface of the water covering the array. The positions of the water jet were measured by multiple-exposure fast framing imaging. In experiments, the apex angle of the array,more » the thickness of the water layer above the arrays, or the material of the wires was altered, which changed the resulting velocities and shapes of the emitted jets. A model that considers the converging stationary flow of a slightly compressible fluid is suggested. The velocities and shapes of the jets obtained by this model agree well with the experimentally measured jet velocities.« less

An electric vehicle propulsion system's impact on battery performance: An overview

NASA Technical Reports Server (NTRS)

Bozek, J. M.; Smithrick, J. J.; Cataldo, R. C.; Ewashinka, J. G.

1980-01-01

The performance of two types of batteries, lead-acid and nickel-zinc, was measured as a function of the charging and discharging demands anticipated from electric vehicle propulsion systems. The benefits of rapid high current charging were mixed: although it allowed quick charges, the energy efficiency was reduced. For low power (overnight) charging the current wave shapes delivered by the charger to the battery tended to have no effect on the battery cycle life. The use of chopper speed controllers with series traction motors resulted in a significant reduction in the energy available from a battery whenever the motor operates at part load. The demand placed on a battery by an electric vehicle propulsion system containing electrical regenerative braking confirmed significant improvment in short term performance of the battery.

Observations of barium ion jets in the magnetosphere using Doppler imaging systems and very sensitive imaging systems using imaging photon detectors

NASA Technical Reports Server (NTRS)

Rees, D.; Conboy, J.; Heinz, W.; Heppner, J. P.

1985-01-01

Observations of four shaped charge releases from rockets launched from Alaska are described. Results demonstrate that imaging and Doppler imaging instruments, based on exploiting the imaging photon detector, provide additional insight into the motion and development of low intensity targets such as the fast ion jets produced by shaped charge releases. It is possible to trace the motion of fast ion jets to very great distances, of the order of 50,000 km, outward along the Earth's magnetic field, when the conditions are suitable for the outward (upward) motion and/or acceleration of such ion jets. It is shown that ion jets, which fade below the lower sensitivity threshold of previous instruments, do not always disappear. There is no evidence of an abrupt field-aligned shear-type acceleration.

Optimal Dynamic Detection of Explosives (ODD-EX)

DTIC Science & Technology

2011-12-29

2. Control of nitromethane photoionization efficiency with shaped femtosecond pulses, J. Roslund, O. Shir, A. Dogariu, R. Miles, H. Rabitz, J. Chem...feedback loop. 2. Control of nitromethane photoionization efficiency with shaped femtosecond pulses, J. Roslund, O. Shir, A. Dogariu, R. Miles, H. Rabitz...resonances that allow a significant increase in the photoionization efficiency of nitromethane with shaped near-infrared femtosecond pulses. The

Negative electrospray ionization on porous supporting tips for mass spectrometric analysis: electrostatic charging effect on detection sensitivity and its application to explosive detection.

PubMed

Wong, Melody Yee-Man; Man, Sin-Heng; Che, Chi-Ming; Lau, Kai-Chung; Ng, Kwan-Ming

2014-03-21

The simplicity and easy manipulation of a porous substrate-based ESI-MS technique have been widely applied to the direct analysis of different types of samples in positive ion mode. However, the study and application of this technique in negative ion mode are sparse. A key challenge could be due to the ease of electrical discharge on supporting tips upon the application of negative voltage. The aim of this study is to investigate the effect of supporting materials, including polyester, polyethylene and wood, on the detection sensitivity of a porous substrate-based negative ESI-MS technique. By using nitrobenzene derivatives and nitrophenol derivatives as the target analytes, it was found that the hydrophobic materials (i.e., polyethylene and polyester) with a higher tendency to accumulate negative charge could enhance the detection sensitivity towards nitrobenzene derivatives via electron-capture ionization; whereas, compounds with electron affinities lower than the cut-off value (1.13 eV) were not detected. Nitrophenol derivatives with pKa smaller than 9.0 could be detected in the form of deprotonated ions; whereas polar materials (i.e., wood), which might undergo competitive deprotonation with the analytes, could suppress the detection sensitivity. With the investigation of the material effects on the detection sensitivity, the porous substrate-based negative ESI-MS method was developed and applied to the direct detection of two commonly encountered explosives in complex samples.

Charged drop dynamics experiment using an electrostatic-acoustic hybrid system

NASA Technical Reports Server (NTRS)

Rhim, W. K.; Chung, S. K.; Trinh, E. H.; Elleman, D. D.

1987-01-01

The design and the performance of an electrostatic-acoustic hybrid system and its application to a charge drop rotation experiment are presented. This system can levitate a charged drop electrostatically and induce drop rotation or oscillation by imposing an acoustic torque or an oscillating acoustic pressure. Using this system, the equilibrium shapes and stability of a rotating charged drop were experimentally investigated. A 3 mm size water drop was rotated as a rigid body and its gyrostatic equilibrium shapes were observed. Families of axisymmetric shapes, two-lobed shapes, and eventual fissioning have been observed. With the assumption of 'effective surface tension' in which the surface charge simply modified the surface tension of neutral liquid, the results agree exceptionally well with the Brown and Scriven's (1980) prediction for uncharged drops.

Ignition of a Deuterium Micro-Detonation with a Gigavolt Super Marx Generator

NASA Astrophysics Data System (ADS)

Winterberg, Friedwardt

2009-09-01

The Centurion-Halite experiment demonstrated the feasibility of igniting a deuterium-tritium micro-explosion with an energy of not more than a few megajoule, and the Mike test, the feasibility of a pure deuterium explosion with an energy of more than 106 MJ. In both cases the ignition energy was supplied by a fission bomb explosive. While an energy of a few megajoule, to be released in the time required of less than 10-9 s, can be supplied by lasers and intense particle beams, this is not enough to ignite a pure deuterium explosion. Because the deuterium-tritium reaction depends on the availability of lithium, the non-fission ignition of a pure deuterium fusion reaction would be highly desirable. It is shown that this goal can conceivably be reached with a "Super Marx Generator", where a large number of "ordinary" Marx generators charge (magnetically insulated) fast high voltage capacitors of a second stage Marx generator, called a "Super Marx Generator", ultimately reaching gigavolt potentials with an energy output in excess of 100 MJ. An intense 107 Ampere-GeV proton beam drawn from a "Super Marx Generator" can ignite a deuterium thermonuclear detonation wave in a compressed deuterium cylinder, where the strong magnetic field of the proton beam entraps the charged fusion reaction products inside the cylinder. In solving the stand-off problem, the stiffness of a GeV proton beam permits to place the deuterium target at a comparatively large distance from the wall of a cavity confining the deuterium micro-explosion.

Transient pulse analysis of ionized electronics exposed to γ-radiation generated from a relativistic electron beam

NASA Astrophysics Data System (ADS)

Min, Sun-Hong; Kwon, Ohjoon; Sattorov, Matlabjon; Baek, In-Keun; Kim, Seontae; Hong, Dongpyo; Jeong, Jin-Young; Jang, Jungmin; Bera, Anirban; Barik, Ranjan Kumar; Bhattacharya, Ranajoy; Cho, Ilsung; Kim, Byungsu; Park, Chawon; Jung, Wongyun; Park, Seunghyuk; Park, Gun-Sik

2018-02-01

When a semiconductor element is irradiated with radiation in the form of a transient pulse emitted from a nuclear explosion, a large amount of charge is generated in a short time in the device. A photocurrent amplified in a certain direction by these types of charges cause the device to break down and malfunction or in extreme cases causes them to burn out. In this study, a pulse-type γ-ray generator based on a relativistic electron beam accelerator (γ=2.2, β=0.89) which functions by means of tungsten impingement was constructed and tested in an effort to investigate the process and effects of the photocurrent formed by electron hole pairs (EHP) generated in a pMOSFET device when a transient radiation pulse is incident in the device. The pulse-type γ-ray irradiating device used here to generate the electron beam current in a short time was devised to allow an increase in the irradiation dose. A precise signal processing circuit was constructed to measure the photocurrent of the small signal generated by the pMOSFET due to the electron beam accelerator pulse signal from the large noise stemming from the electromagnetic field around the relativistic electron beam accelerator. The pulse-type γ-ray generator was installed to meet the requirements of relativistic electron beam accelerators, and beam irradiation was conducted after a beam commissioning step.

Anomalous metallic state with strong charge fluctuations in BaxTi8O16 +δ revealed by hard x-ray photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Dash, S.; Kajita, T.; Okawa, M.; Saitoh, T.; Ikenaga, E.; Saini, N. L.; Katsufuji, T.; Mizokawa, T.

2018-04-01

We have studied a charge-orbital driven metal-insulator transition (MIT) in hollandite-type BaxTi8O16 +δ by means of hard x-ray photoemission spectroscopy (HAXPES). The Ti 2 p HAXPES indicates strong Ti3 +/Ti4 + charge fluctuation in the metallic phase above the MIT temperature. The metallic phase is characterized by a power-law spectral function near the Fermi level which would be a signature of bad metal with non-Drude polaronic behavior. The power-law spectral shape is associated with the large Seebeck coefficient of the metallic phase in BaxTi8O16 +δ .

Influence of Axisymmetrically Deformed Explosions in Type II Supernovae on the Reproduction of the Solar System Abundances

NASA Astrophysics Data System (ADS)

Nagataki, Shigehiro

1999-01-01

We have tried to reproduce the solar system abundances using the nucleosynthesis products of Type Ia and Type II supernovae. In particular, we examined the effects of axisymmetrically deformed explosions in Type II supernovae. 44Ca and 47,48Ti are enhanced considerably in axisymmetrically deformed explosion models because of the active alpha-rich freezeout. The enhancement of nuclei around A=45 is a welcome result since it solves the problem of the nuclei shortage. Moreover, 59Co, 63,65Cu, and 66Zn are enhanced enough to reproduce the solar system abundances. The enhancement of Cu and Zn means the possibility that these nuclei, which have been said to be produced by the slow process, can be synthesized fairly well during the explosive nucleosynthesis. To discuss their origin quantitatively, the position of the mass cut is a very important parameter that is very difficult to determine numerically at present. We also stress that an axisymmetrically deformed explosion of Type II supernovae of the degree that is considered in this analysis is not excluded by the results of calculations of explosive nucleosynthesis, that is, the nucleosynthesis products are not extremely disturbed and the solar system abundances can be reproduced fairly well by the axisymmetrically deformed explosion models. This conclusion will be good for the theory of core collapse including the rotation of an iron core, magnetic field, and axisymmetrically modified neutrino radiation from a rotating protoneutron star, which possibly can cause an axisymmetrically deformed explosion.

Rebounding of a shaped-charge jet

NASA Astrophysics Data System (ADS)

Proskuryakov, E. V.; Sorokin, M. V.; Fomin, V. M.

2007-09-01

The phenomenon of rebounding of a shaped-charge jet from the armour surface with small angles between the jet axis and the target surface is considered. Rebounding angles as a function of jet velocity are obtained in experiments for a copper shaped-charge jet. An engineering calculation technique is developed. The results calculated with the use of this technique are in reasonable agreement with experimental data.

An Examination of Protocols for The Collection of Munitions-Derived Explosives Residues on Snow-Covered Ice

DTIC Science & Technology

2005-04-01

with a single demolition block charge of C4 (DODIC M023) as the donor charge. An M739 point- detonating fuze (DODIC N340) was installed in each round...All rounds contained a supplementary TNT charge in the fuze well below the M739 fuze (see Appendix A). Figure 3 shows the setup common for all the...Charge, demolition block, Comp C4, M112 MA-97A003-007A 16 1390010809447 N340 Fuze, point detonating, M739 MA-84B007-013 7 Notes: Drawn from Fort

Compendium of Nitromethane Data Relevant to the Tactical Explosive System (TEXS) Program

DTIC Science & Technology

1989-04-01

reduced charge size. Confined NM in glass tubes and added silica impurities with a known particle size distribution, and used guar gum to hold silica...internal ignition test. The explosive in the pipe bomb is subjected to the action of a cen- trally located black powder (20 g) igniter. A positive...Laboratory 2800 Powder Mill Road Adelphia, MD 20783-1145 Commander U.S. Army Test and Evaluation Command ATTN: AMSTE-TE-AT, B. Hawley Aberdeen

Mitigation of Explosive Blast Effects on Vehicle Floorboard

DTIC Science & Technology

2008-07-01

dimensions as the first frame. The floorboard, hull, and frames are fastened to one another by eighteen 3/8 in stainless steel bolts, as shown in Figure...1.5]. When the buried charge is detonated, soil and hot gas are ejected from the sand bed creating a crater . The soil is ejected at supersonic...a short interval of time. The ejected sand, the resulting crater , and the target can form a sort of enclosure around the high pressure explosive

Shock initiated reactions of reactive multi-phase blast explosives

NASA Astrophysics Data System (ADS)

Wilson, Dennis; Granier, John; Johnson, Richard; Littrell, Donald

2017-01-01

This paper describes a new class of non-ideal explosive compositions made of perfluoropolyether (PFPE), nanoaluminum, and a micron-size, high mass density, reactive metal. Unlike high explosives, these compositions release energy via a fast self-oxidized combustion wave rather than a true self-sustaining detonation. Their reaction rates are shock dependent and they can be overdriven to change their energy release rate. These compositions are fuel rich and have an extended aerobic energy release phase. The term "reactive multiphase blast" refers to the post-dispersion blast behavior: multiphase in that there are a gas phase that imparts pressure and a solid (particulate) phase that imparts energy and momentum [1]; and reactive in that the hot metal particles react with atmospheric oxygen and the explosive gas products to give an extended pressure pulse. Tantalum-based RMBX formulations were tested in two spherical core-shell configurations - an RMBX shell exploded by a high explosive core, and an RMBX core imploded by a high explosive shell. The fireball and blast characteristics were compared to a C-4 baseline charge.

Coulomb explosion of “hot spot”

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oreshkin, V. I., E-mail: oreshkin@ovpe.hcei.tsc.ru; Tomsk Polytechnic University, Tomsk; Oreshkin, E. V.

The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulombmore » explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed, and the estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.« less

Field emission and explosive electron emission process in focused ion beam fabricated platinum and tungsten three-dimensional overhanging nanostructure

NASA Astrophysics Data System (ADS)

Singh, Abhishek Kumar

2018-06-01

Three-dimensional platinum and tungsten overhanging nanogap (∼70 nm) electrodes are fabricated on a glass substrate using focused ion beam milling and chemical vapour deposition processes. Current-voltage (I-V) characteristics of the devices measured at a pressure of ∼10-6 mbar shows space-charge emission followed by the Fowler-Nordheim (F-N) field emission. After the F-N emission, the system enters into an explosive emission process, at a higher voltage generating a huge current. We observe a sharp and abrupt rise in the emission current which marks the transition from the F-N emission to the explosive emission state. The explosive emission process is destructive in nature and yields micro-/nano-size spherical metal particles. The chemical compositions and the size-distribution of such particles are performed.

Tuning the Fabrication of Nanostructures by Low-Energy Highly Charged Ions.

PubMed

El-Said, Ayman S; Wilhelm, Richard A; Heller, Rene; Sorokin, Michael; Facsko, Stefan; Aumayr, Friedrich

2016-09-16

Slow highly charged ions have been utilized recently for the creation of monotype surface nanostructures (craters, calderas, or hillocks) in different materials. In the present study, we report on the ability of slow highly charged xenon ions (^{129}Xe^{Q+}) to form three different types of nanostructures on the LiF(100) surface. By increasing the charge state from Q=15 to Q=36, the shape of the impact induced nanostructures changes from craters to hillocks crossing an intermediate stage of caldera structures. A dimensional analysis of the nanostructures reveals an increase of the height up to 1.5 nm as a function of the potential energy of the incident ions. Based on the evolution of both the geometry and size of the created nanostructures, defect-mediated desorption and the development of a thermal spike are utilized as creation mechanisms of the nanostructures at low and high charge states, respectively.

Explosive X-point collapse in relativistic magnetically dominated plasma

NASA Astrophysics Data System (ADS)

Lyutikov, Maxim; Sironi, Lorenzo; Komissarov, Serguei S.; Porth, Oliver

2017-12-01

The extreme properties of the gamma-ray flares in the Crab nebula present a clear challenge to our ideas on the nature of particle acceleration in relativistic astrophysical plasma. It seems highly unlikely that standard mechanisms of stochastic type are at work here and hence the attention of theorists has switched to linear acceleration in magnetic reconnection events. In this series of papers, we attempt to develop a theory of explosive magnetic reconnection in highly magnetized relativistic plasma which can explain the extreme parameters of the Crab flares. In the first paper, we focus on the properties of the X-point collapse. Using analytical and numerical methods (fluid and particle-in-cell simulations) we extend Syrovatsky's classical model of such collapse to the relativistic regime. We find that the collapse can lead to the reconnection rate approaching the speed of light on macroscopic scales. During the collapse, the plasma particles are accelerated by charge-starved electric fields, which can reach (and even exceed) values of the local magnetic field. The explosive stage of reconnection produces non-thermal power-law tails with slopes that depend on the average magnetization . For sufficiently high magnetizations and vanishing guide field, the non-thermal particle spectrum consists of two components: a low-energy population with soft spectrum that dominates the number census; and a high-energy population with hard spectrum that possesses all the properties needed to explain the Crab flares.

Testing Shaped Charges in Unfrozen and Frozen Silt in Alaska

DTIC Science & Technology

1982-03-01

AwTrRACT Cte sm reveg N emeagay -id d*ify by block number) SBorehole blasting tests using 15- and 40-lb charges were conducted in silt at Fort Wainwright...Table 3-5 of the manual, performance data on the blasting of boreholes with shaped charges are presented. Of particular interest in that table a-e the...Commander of the 47th Engineers at Fort Wainwright asked if I could verify his findings that the M2A4 (15-1b) shaped charge cannot produce a borehole in

Simulations of Si-PIN photodiode based detectors for underground explosives enhanced by ammonium nitrate

NASA Astrophysics Data System (ADS)

Yücel, Mete; Bayrak, Ahmet; Yücel, Esra Barlas; Ozben, Cenap S.

2018-02-01

Massive Ammonium Nitrate (NH4-NO3) based explosives buried underground are commonly used in terror attacks. These explosives can be detected using neutron scattering method with some limitations. Simulations are very useful tools for designing a possible detection system for these kind of explosives. Geant4 simulations were used for generating neutrons at 14 MeV energy and tracking them through the scattering off the explosive embedded in soil. Si-PIN photodiodes were used as detector elements in the design for their low costs and simplicity for signal readout electronics. Various neutron-charge particle converters were applied on to the surface of the photodiodes to increase the detection efficiency. Si-PIN photodiodes coated with 6LiF provided the best result for a certain energy interval. Energy depositions in silicon detector from all secondary particles generated including photons were taken into account to generate a realistic background. Humidity of soil, one of the most important parameter for limiting the detection, was also studied.

Emergent explosive synchronization in adaptive complex networks

NASA Astrophysics Data System (ADS)

Avalos-Gaytán, Vanesa; Almendral, Juan A.; Leyva, I.; Battiston, F.; Nicosia, V.; Latora, V.; Boccaletti, S.

2018-04-01

Adaptation plays a fundamental role in shaping the structure of a complex network and improving its functional fitting. Even when increasing the level of synchronization in a biological system is considered as the main driving force for adaptation, there is evidence of negative effects induced by excessive synchronization. This indicates that coherence alone cannot be enough to explain all the structural features observed in many real-world networks. In this work, we propose an adaptive network model where the dynamical evolution of the node states toward synchronization is coupled with an evolution of the link weights based on an anti-Hebbian adaptive rule, which accounts for the presence of inhibitory effects in the system. We found that the emergent networks spontaneously develop the structural conditions to sustain explosive synchronization. Our results can enlighten the shaping mechanisms at the heart of the structural and dynamical organization of some relevant biological systems, namely, brain networks, for which the emergence of explosive synchronization has been observed.

Emergent explosive synchronization in adaptive complex networks.

PubMed

Avalos-Gaytán, Vanesa; Almendral, Juan A; Leyva, I; Battiston, F; Nicosia, V; Latora, V; Boccaletti, S

2018-04-01

Adaptation plays a fundamental role in shaping the structure of a complex network and improving its functional fitting. Even when increasing the level of synchronization in a biological system is considered as the main driving force for adaptation, there is evidence of negative effects induced by excessive synchronization. This indicates that coherence alone cannot be enough to explain all the structural features observed in many real-world networks. In this work, we propose an adaptive network model where the dynamical evolution of the node states toward synchronization is coupled with an evolution of the link weights based on an anti-Hebbian adaptive rule, which accounts for the presence of inhibitory effects in the system. We found that the emergent networks spontaneously develop the structural conditions to sustain explosive synchronization. Our results can enlighten the shaping mechanisms at the heart of the structural and dynamical organization of some relevant biological systems, namely, brain networks, for which the emergence of explosive synchronization has been observed.

Three-phase hypervelocity projectile launcher

DOEpatents

Fugelso, L. Erik; Langner, Gerald C.; Burns, Kerry L.; Albright, James N.

1994-01-01

A hypervelocity projectile launcher for use in perforating borehole casings provides improved penetration into the surrounding rock structure. The launcher includes a first cylinder of explosive material that defines an axial air-filled cavity, a second cylinder of explosive material defining an axial frustum-shaped cavity abutting and axially aligned with the first cylinder. A pliant washer is located between and axially aligned with the first and second cylinders. The frustum shaped cavity is lined with a metal liner effective to form a projectile when the first and second cylinders are detonated. The washer forms a unique intermediate projectile in advance of the liner projectile and enables the liner projectile to further penetrate into and fracture the adjacent rock structure.

Deployment of Shaped Charges by a Semi-Autonomous Ground Vehicle

DTIC Science & Technology

2007-06-01

lives on a daily basis. BigFoot seeks to replace the local human component by deploying and remotely detonating shaped charges to destroy IEDs...robotic arm to deploy and remotely detonate shaped charges. BigFoot incorporates improved communication range over previous Autonomous Ground Vehicles...and an updated user interface that includes controls for the arm and camera by interfacing multiple microprocessors. BigFoot is capable of avoiding

Shaped Charge Liner Materials: Resources, Processes, Properties, Costs, and Applications

DTIC Science & Technology

1991-02-01

SUBTITLE 5. FUNDING NUMBERS Shaped Charge Liner Materials: Resources, Processes, Properties, Costs, and Applications 2 6. AUTHOC Steven M. Buc 7...summaries of the mineral availability, Cq prmarymetal refinement processeb, material costs in raw form and as finished shaped charge liners , relevant... liner materials. 94-11479 gI 14, SUBJECT TERMS iSt NUMBER OF PAGIS 13chrg wrhad :xplosively formed penetrators material R. PRCE COEV" processing

Active experiments using rocket-borne shaped charge barium releases. [solar-terrestrial magnetospheric physics

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Davis, T. N.

1980-01-01

A reliable payload system and scaled down shaped charges were developed for carrying out experiments in solar-terrestrial magnetospheric physics. Four Nike-Tomahawk flights with apogees near 450 km were conducted to investigate magnetospheric electric fields, and two Taurus-Tomahawk rockets were flown in experiments on the auroral acceleration process in discrete auroras. In addition, a radial shaped charge was designed for plasma perturbation experiments.

Kink-bands: Shock deformation of biotite resulting from a nuclear explosion

USGS Publications Warehouse

Cummings, D.

1965-01-01

Microscopic examination of granodiorite samples from the shock region around a nuclear explosion reveals sharply folded lens-shaped zones (kink-bands) in the mineral biotite. Fifty percent of these zones are oriented approximately 90?? to the direction of shock-wave propagation, but other zones are symmetrically concentrated at shear angles of 50?? and 70?? to the direction of shock-wave propagation.

Optical ordnance system for use in explosive ordnance disposal activities

NASA Technical Reports Server (NTRS)

Merson, J. A.; Salas, F. J.; Helsel, F.M.

1994-01-01

A portable hand-held solid state rod laser system and an optically-ignited detonator have been developed for use in explosive ordnance disposal (EOD) activities. Laser prototypes from Whittaker Ordnance and Universal Propulsion have been tested and evaluated. The optical detonator contains 2-(5 cyanotetrazolato) pentaamine cobalt(III) perchlorate (CP) as the DDT column and the explosive Octahydro- 1,3,5,7 - tetrazocine (HMX) as the output charge. The laser is designed to have an output of 150 mJ in a 500 microsecond pulse. This output allows firing through 2000 meters of optical fiber. The detonator can also be ignited with a portable laser diode source through a shorter length of fiber.

24. BUILDING NO. 452, ORDNANCE FACILITY (BAG CHARGE FILLING PLANT), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. BUILDING NO. 452, ORDNANCE FACILITY (BAG CHARGE FILLING PLANT), INTERIOR VIEW LOOKING WEST AT NORTH END OF CENTRAL CORRIDOR (ROOM 3). STAIRWAY WORKBENCH WITH COMPRESSED-AIR POWERED CARTRIDGE LOADER. ARMORED PASS-THROUGH OF TRANSFER BOX FOR PASSING EXPLOSIVES MATERIALS THROUGH TO NEXT ROOM TO THE NORTH. - Picatinny Arsenal, 400 Area, Gun Bag Loading District, State Route 15 near I-80, Dover, Morris County, NJ

Particle shape effect on heat transfer performance in an oscillating heat pipe.

PubMed

Ji, Yulong; Wilson, Corey; Chen, Hsiu-Hung; Ma, Hongbin

2011-04-05

The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP.

Particle shape effect on heat transfer performance in an oscillating heat pipe

PubMed Central

2011-01-01

The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP. PMID:21711830

Ion-induced nucleation in solution: promotion of solute nucleation in charged levitated droplets.

PubMed

Draper, Neil D; Bakhoum, Samuel F; Haddrell, Allen E; Agnes, George R

2007-09-19

We have investigated the nucleation and growth of sodium chloride in both single quiescent charged droplets and charged droplet populations that were levitated in an electrodynamic levitation trap (EDLT). In both cases, the magnitude of a droplet's net excess charge (ions(DNEC)) influenced NaCl nucleation and growth, albeit in different capacities. We have termed the phenomenon ion-induced nucleation in solution. For single quiescent levitated droplets, an increase in ions(DNEC) resulted in a significant promotion of NaCl nucleation, as determined by the number of crystals observed. For levitated droplet populations, a change in NaCl crystal habit, from regular cubic shapes to dome-shaped dendrites, was observed once a surface charge density threshold of -9 x 10(-4) e.nm(-2) was surpassed. Although promotion of NaCl nucleation was observed for droplet population experiments, this can be attributed in part to the increased rate of solvent evaporation observed for levitated droplet populations having a high net charge. Promotion of nucleation was also observed for two organic acids, 2,4,6-trihydroxyacetophenone monohydrate (THAP) and alpha-cyano-4-hydroxycinnamic acid (CHCA). These results are of direct relevance to processes that occur in both soft-ionization techniques for mass spectrometry and to a variety of industrial processes. To this end, we have demonstrated the use of ion-induced nucleation in solution to form ammonium nitrate particles from levitated droplets to be used in in vitro toxicology studies of ambient particle types.

Shallow magma diversions during explosive diatreme-forming eruptions.

PubMed

Le Corvec, Nicolas; Muirhead, James D; White, James D L

2018-04-13

The diversion of magma is an important mechanism that may lead to the relocation of a volcanic vent. Magma diversion is known to occur during explosive volcanic eruptions generating subterranean excavation and remobilization of country and volcanic rocks. However, feedbacks between explosive crater formation and intrusion processes have not been considered previously, despite their importance for understanding evolving hazards during volcanic eruptions. Here, we apply numerical modeling to test the impacts of excavation and subsequent infilling of diatreme structures on stress states and intrusion geometries during the formation of maar-diatreme complexes. Explosive excavation and infilling of diatremes affects local stress states which inhibits magma ascent and drives lateral diversion at various depths, which are expected to promote intra-diatreme explosions, host rock mixing, and vent migration. Our models demonstrate novel mechanisms explaining the generation of saucer-shaped sills, linked with magma diversion and enhanced intra-diatreme explosive fragmentation during maar-diatreme volcanism. Similar mechanisms will occur at other volcanic vents producing crater-forming eruptions.

Humanitarian IED clearance in Colombia

NASA Astrophysics Data System (ADS)

Hendrickx, J. M. H.; Molina, A.; Diaz, D.; Grasmueck, M.; Moreno, H. A.; Hernández, R. D.

2008-04-01

The development of Improvised Explosive Devices (IED's) by insurgents in Colombia is characterized by a quick response to counter IED measures. Many current IED's do not contain any metal parts and can have any shape or form. Due to the low metal content or the absence of any metal parts, sensors based on metal detection are not useful anymore. Due to the wide variety of sizes, shapes, and enclosure materials of current IED's, one and two-dimensional GPR sensors using a "library" of known shapes as well as acoustic sensors using material characteristic frequencies have become ineffective. Therefore, the Colombian experience strongly suggests that chemical sensors are the way for IED detection in soils since they do not depend on IED metal content, size, or shape but only on the presence of explosives, a necessary ingredient for any IED. Promising recently developed chemical sensors make use of semiconducting organic polymers (SOPs) such as FIDO and laser-induced breakdown spectroscopy (LIBS). Once an explosive has been detected, the IED needs to be identified and located. Therefore, there is a need for three-dimensional high resolution scans for identification of all subsoil features including rocks, roots, and IED's. The recently developed 3D-GPR (Ground Penetrating Radar) can map all features of the subsoil with a spatial resolution of about 2 cm or less. The objectives of this contribution are to inform about the IED problem in Colombia and how novel technologies may contribute to humanitarian IED clearance under humid tropical conditions.

29 CFR 1926.912 - Underwater blasting.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... herein on handling and storing explosives. (h) When more than one charge is placed under water, a float...

29 CFR 1926.912 - Underwater blasting.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... herein on handling and storing explosives. (h) When more than one charge is placed under water, a float...

29 CFR 1926.912 - Underwater blasting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... herein on handling and storing explosives. (h) When more than one charge is placed under water, a float...

29 CFR 1926.912 - Underwater blasting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... herein on handling and storing explosives. (h) When more than one charge is placed under water, a float...

29 CFR 1926.912 - Underwater blasting.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... herein on handling and storing explosives. (h) When more than one charge is placed under water, a float...

Apparatus and method for sealing perforated well casing

DOEpatents

Blount, Curtis G.; Benham, Robert A.; Brock, Jerry L.; Emerson, John A.; Ferguson, Keith R.; Scheve, Donald F.; Schmidt, Joseph H.; Schuler, Karl W.; Stanton, Philip L.

1997-01-01

Perforations and other openings in well casings, liners and other conduits may be substantially blocked or sealed to prevent fluid flow between the casing or liner interior and an earth formation by placing a radially expansible sleeve adjacent the perforations or openings and urging the sleeve into forcible engagement with the casing or inner wall using an explosive charge. An apparatus including a radially contracted sleeve formed by a coiled plate member or a tubular member having flutes defined by external and internal folds, may be deployed into a well casing or liner through a production or injection tubing string and on the end of a flexible cable or coilable tubing. An explosive charge disposed on the apparatus and within the sleeve may be detonated to urge the sleeve into forcible engagement with the casing inner wall.

Apparatus and method for sealing perforated well casing

DOEpatents

Blount, C.G.; Benham, R.A.; Brock, J.L.; Emerson, J.A.; Ferguson, K.R.; Scheve, D.F.; Schmidt, J.H.; Schuler, K.W.; Stanton, P.L.

1997-03-25

Perforations and other openings in well casings, liners and other conduits may be substantially blocked or sealed to prevent fluid flow between the casing or liner interior and an earth formation by placing a radially expansible sleeve adjacent the perforations or openings and urging the sleeve into forcible engagement with the casing or inner wall using an explosive charge. An apparatus including a radially contracted sleeve formed by a coiled plate member or a tubular member having flutes defined by external and internal folds, may be deployed into a well casing or liner through a production or injection tubing string and on the end of a flexible cable or coilable tubing. An explosive charge disposed on the apparatus and within the sleeve may be detonated to urge the sleeve into forcible engagement with the casing inner wall. 17 figs.

Shock waves raised by explosions in space as sources of ultra-high-energy cosmic rays

NASA Astrophysics Data System (ADS)

Kichigin, Gennadiy

2015-03-01

The paper discusses the possibility of particle acceleration up to ultrahigh energies in the relativistic waves generated by various explosive processes in the interstellar medium. We propose to use the surfatron mechanism of acceleration (surfing) of charged particles trapped in the front of relativistic waves as a generator of high-energy cosmic rays (CRs). Conditions under which surfing in these waves can be made are studied thoroughly. Ultra-high-energy CRs (up to 10^20 eV) are shown to be obtained due to the surfing in the relativistic plane and spherical waves. Surfing is supposed to take place in nonlinear Langmuir waves excited by powerful electromagnetic radiation or relativistic beams of charged particles, as well as in strong shock waves generated by relativistic jets or spherical formations that expand fast (fireballs).

Reverse slapper detonator

DOEpatents

Weingart, Richard C.

1990-01-01

A reverse slapper detonator (70), and methodology related thereto, are provided. The detonator (70) is adapted to be driven by a pulse of electric power from an external source (80). A conductor (20) is disposed along the top (14), side (18), and bottom (16) surfaces of a sheetlike insulator (12). Part of the conductor (20) comprises a bridge (28), and an aperture (30) is positioned within the conductor (20), with the bridge (28) and the aperture (30) located on opposite sides of the insulator (12). A barrel (40) and related explosive charge (50) are positioned adjacent to and in alignment with the aperture (30), and the bridge (28) is buttressed with a backing layer (60). When the electric power pulse vaporizes the bridge (28), a portion of the insulator (12) is propelled through the aperture (30) and barrel (40), and against the explosive charge (50), thereby detonating it.

The characterization and evaluation of accidental explosions

NASA Technical Reports Server (NTRS)

Strehlow, R. A.; Baker, W. E.

1975-01-01

Accidental explosions are discussed from a number of viewpoints. First, all accidental explosions, intentional explosions and natural explosions are characterized by type. Second, the nature of the blast wave produced by an ideal (point source or HE) explosion is discussed to form a basis for describing how other explosion processes yield deviations from ideal blast wave behavior. The current status blast damage mechanism evaluation is also discussed. Third, the current status of our understanding of each different category of accidental explosions is discussed in some detail.

Multi-factor Analysis of Pre-control Fracture Simulations about Projectile Material

NASA Astrophysics Data System (ADS)

Wan, Ren-Yi; Zhou, Wei

2016-05-01

The study of projectile material pre-control fracture is helpful to improve the projectile metal effective fragmentation and the material utilization rate. Fragments muzzle velocity and lethality can be affected by the different explosive charge and the way of initiation. The finite element software can simulate the process of projectile explosive rupture which has a pre-groove in the projectile shell surface and analysis of typical node velocity change with time, to provides a reference for the design and optimization of precontrol frag.

Experimental Investigation of Shock Initiation in Mixtures of Manganese and Sulfur

NASA Astrophysics Data System (ADS)

Jetté, F. X.; Goroshin, S.; Higgins, A. J.

2009-12-01

Equimolar mixtures of manganese powder and sulfur at different starting densities were tested in two different types of steel recovery capsules in order to study the shock initiation phenomenon in Self-Propagating High-Temperature Synthesis (SHS) mixtures. Two different sizes of Mn particles were used for these experiments, <10 μm and -325 mesh (<44 μm). This mixture was selected due to the large exothermic heat release of the manganese-sulfur reaction (214 kJ/mol), which causes the reaction to be self-sustaining once initiated. The test samples were placed in planar recovery capsules and a strong shock was delivered via the detonation of a charge of amine-sensitized nitromethane. Various shock strengths were achieved by placing different thicknesses of PMMA attenuator discs between the explosive charge and the capsule. The results confirmed that shock-induced reactions can be produced in highly non-porous mixtures. It was also found that shock interactions with the side walls of the recovery capsule can play a significant role in the initiation.

Theoretical insight into the sensitive mechanism of multilayer-shaped cocrystal explosives: compression and slide.

PubMed

Gao, Hong-fei; Zhang, Shu-hai; Ren, Fu-de; Gou, Rui-jun; Han, Gang; Wu, Jing-bo; Ding, Xiong; Zhao, Wen-hu

2016-05-01

Multilayer-shaped compression and slide models were employed to investigate the complex sensitive mechanisms of cocrystal explosives in response to external mechanical stimuli. Here, density functional theory (DFT) calculations implementing the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) with the Tkatchenko-Scheffler (TS) dispersion correction were applied to a series of cocrystal explosives: diacetone diperoxide (DADP)/1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), DADP/1,3,5-tribromo-2,4,6-trinitrobenzene (TBTNB) and DADP/1,3,5-triiodo-2,4,6-trinitrobenzene (TITNB). The results show that the GGA-PBE-TS method is suitable for calculating these cocrystal systems. Compression and slide models illustrate well the sensitive mechanism of layer-shaped cocrystals of DADP/TCTNB and DADP/TITNB, in accordance with the results from electrostatic potentials and free space per molecule in cocrystal lattice analyses. DADP/TCTNB and DADP/TBTNB prefer sliding along a diagonal direction on the a-c face and generating strong intermolecular repulsions, compared to DADP/TITNB, which slides parallel to the b-c face. The impact sensitivity of DADP/TBTNB is predicted to be the same as that of DADP/TCTNB, and the impact sensitivity of DADP/TBTNB may be slightly more insensitive than that of DADP and much more sensitive than that of TBTNB.

Free form hemispherical shaped charge

DOEpatents

Haselman, L.C. Jr.

1996-06-04

A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved. 8 figs.

Free form hemispherical shaped charge

DOEpatents

Haselman, Jr., Leonard C.

1996-01-01

A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved.

Monte Carlo simulation of explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator.

PubMed

Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

2014-12-01

An explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator has been simulated using the Monte Carlo N-Particle Transport Code (MCNP5). Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma emission (10.82MeV) following radiative neutron capture by (14)N nuclei. The explosive detection system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF) driven ion source and nominal yield of about 10(10) fast neutrons per second (E=2.5MeV). Polyethylene and paraffin were used as moderators with borated polyethylene and lead as neutron and gamma ray shielding, respectively. The shape and the thickness of the moderators and shields are optimized to produce the highest thermal neutron flux at the position of the explosive and the minimum total dose at the outer surfaces of the explosive detection system walls. In addition, simulation of the response functions of NaI, BGO, and LaBr3-based γ-ray detectors to different explosives is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

Method for explosive expansion toward horizontal free faces for forming an in situ oil shale retort

DOEpatents

Ricketts, Thomas E.

1980-01-01

Formation is excavated from within a retort site in formation containing oil shale for forming a plurality of vertically spaced apart voids extending horizontally across different levels of the retort site, leaving a separate zone of unfragmented formation between each pair of adjacent voids. Explosive is placed in each zone, and such explosive is detonated in a single round for forming an in situ retort containing a fragmented permeable mass of formation particles containing oil shale. The same amount of formation is explosively expanded upwardly and downwardly toward each void. A horizontal void excavated at a production level has a smaller horizontal cross-sectional area than a void excavated at a lower level of the retort site immediately above the production level void. Explosive in a first group of vertical blast holes is detonated for explosively expanding formation downwardly toward the lower void, and explosive in a second group of vertical blast holes is detonated in the same round for explosively expanding formation upwardly toward the lower void and downwardly toward the production level void for forming a generally T-shaped bottom of the fragmented mass.

Computer simulation of metal wire explosion under high rate heating

NASA Astrophysics Data System (ADS)

Zolnikov, K. P.; Kryzhevich, D. S.; Korchuganov, A. V.

2017-05-01

Synchronous electric explosion of metal wires and synthesis of bicomponent nanoparticles were investigated on the base of molecular dynamics method. Copper and nickel nanosized crystallites of cylindrical shape were chosen as conductors for explosion. The embedded atom approximation was used for calculation of the interatomic interactions. The agglomeration process after explosion metal wires was the main mechanism for particle synthesis. The distribution of chemical elements was non-uniform over the cross section of the bicomponent particles. The copper concentration in the surface region was higher than in the bulk of the synthesized particle. By varying the loading parameters (heating temperature, the distance between the wires) one can control the size and internal structure of the synthesized bicomponent nanoparticles. The obtained results showed that the method of molecular dynamics can be effectively used to determine the optimal technological mode of nanoparticle synthesis on the base of electric explosion of metal wires.

Semiconductor bridge (SCB) igniter

DOEpatents

Bickes, Jr., Robert W.; Schwarz, Alfred C.

1987-01-01

In an explosive device comprising an explosive material which can be made to explode upon activation by activation means in contact therewith; electrical activation means adaptable for activating said explosive material such that it explodes; and electrical circuitry in operation association with said activation means; there is an improvement wherein said activation means is an electrical material which, at an elevated temperature, has a negative temperature coefficient of electrical resistivity and which has a shape and size and an area of contact with said explosive material sufficient that it has an electrical resistance which will match the resistance requirements of said associated electrical circuitry when said electrical material is operationally associated with said circuitry, and wherein said electrical material is polycrystalline; or said electrical material is crystalline and (a) is mounted on a lattice matched substrate or (b) is partially covered with an intimately contacting metallization area which defines its area of contact with said explosive material.

Strength of the phase change materials on loading with the products of electric explosion of conductors

NASA Astrophysics Data System (ADS)

Savenkov, Georgiy; Morozov, Viktor; Kats, Victor

2018-05-01

Results of the experimentation on the destruction of the phase change materials (beeswax and paraffin) by the electric explosion of conductors are presented. The process of the explosion of copper and nickel titanium wires in both pure PCM and its mixture with nonosized additives of cuprous oxide is analyzed. The effect of this additive on the process of the expansion of the electric-discharge plasma during the electric explosion of conductors and on the strength of composite materials is demonstrated. The piezoprobe-based method of measurement of the radial pressure during samples destruction is developed. The experiments made it possible to determine the dimensions of the melting channel formed inside the samples during the explosion and the subsequent expansion of the electric-discharge plasma. The experiments are performed on the generator of short-term high-voltage pulses capable to shape the voltage of (10-24) kV.

Dual Fragment Impact of PBX Charges

NASA Astrophysics Data System (ADS)

Haskins, Peter; Briggs, Richard; Leeming, David; White, Nathan; Cheese, Philip; DE&S MoD UK Team; Ordnance Test Solutions Ltd Team

2017-06-01

Fragment impact can pose a significant hazard to many systems containing explosives or propellants. Testing for this threat is most commonly carried out using a single fragment. However, it can be argued that an initial fragment strike (or strikes) could sensitise the energetic material to subsequent impacts, which may then lead to a more violent reaction than would have been predicted based upon single fragment studies. To explore this potential hazard we have developed the capability to launch 2 fragments from the same gun at a range of velocities, and achieve impacts on an acceptor charge with good control over the spatial and temporal separation of the strikes. In this paper we will describe in detail the experimental techniques we have used, both to achieve the dual fragment launch and observe the acceptor charge response. In addition, we will describe the results obtained against PBX filled explosive targets; discuss the mechanisms controlling the target response and their significance for vulnerability assessment. Results of these tests have clearly indicated the potential for detonation upon the second strike, at velocities well below those needed for shock initiation by a single fragment.

Unconventional maar diatreme and associated intrusions in the soft sediment-hosted Mardoux structure (Gergovie, France)

NASA Astrophysics Data System (ADS)

Valentine, Greg A.; van Wyk de Vries, Benjamin

2014-03-01

A Miocene age volcanic-hypabyssal structure comprising volcaniclastic deposits and mafic intrusions is exposed with vertical relief of ˜110 m on the side of Gergovie Plateau (Auvergne, France). Three main volcaniclastic facies are: (1) Fluidal tuff breccia composed of juvenile basalt and sediment clasts with dominantly fluidal shapes, with several combinations of basalt and sediment within individual clasts. (2) Thickly bedded lapilli tuff composed of varying proportions of fine-grained sediment derived from Oligocene-Miocene lacustrine marls and mudstones and basaltic lapilli, blocks, and bombs. (3) Planar-bedded tuff forming thin beds of fine to coarse ash-size sedimentary material and basalt clasts. Intrusive bodies in the thickly bedded lapilli tuff range from irregularly shaped and anastomosing dikes and sills of meters to tens of meters in length, to a main feeder dike that is up to ˜20 m wide, and that flares into a spoon-shaped sill at ˜100 m in diameter and 10-20 m thick in the eastern part of the structure. Volcaniclastic deposits and structural features suggest that ascending magma entrained soft, saturated sediment host material into the feeder dike and erupted fluidal magma and wet sediment via weak, Strombolian-like explosions. Host sediment and erupted material subsided to replace the extracted sediments, producing the growth subsidence structure that is similar to upper diatreme facies in typical maar diatremes but lacks evidence for explosive disruption of diatreme fill. Irregularly shaped small intrusions extended from the main feeder dike into the diatreme, and many were disaggregated due to shifting and subsidence of diatreme fill and recycled via eruption. The Mardoux structure is an "unconventional" maar diatreme in that it was produced mainly by weak explosive activity rather than by violent phreatomagmatic explosions and is an example of complex coupling between soft sediment and ascending magma.

Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids

NASA Astrophysics Data System (ADS)

Pontalier, Q.; Loiseau, J.; Goroshin, S.; Frost, D. L.

2018-04-01

The attenuation of a blast wave from a high-explosive charge surrounded by a layer of inert material is investigated experimentally in a spherical geometry for a wide range of materials. The blast wave pressure is inferred from extracting the blast wave velocity with high-speed video as well as direct measurements with pressure transducers. The mitigant consists of either a packed bed of particles, a particle bed saturated with water, or a homogeneous liquid. The reduction in peak blast wave overpressure is primarily dependent on the mitigant to explosive mass ratio, M/C, with the mitigant material properties playing a secondary role. Relative peak pressure mitigation reduces with distance and for low values of M/C (< 10) can return to unmitigated pressure levels in the mid-to-far field. Solid particles are more effective at mitigating the blast overpressure than liquids, particularly in the near field and at low values of M/C, suggesting that the energy dissipation during compaction, deformation, and fracture of the powders plays an important role. The difference in scaled arrival time of the blast and material fronts increases with M/C and scaled distance, with solid particles giving the largest separation between the blast wave and cloud of particles. Surrounding a high-explosive charge with a layer of particles reduces the positive-phase blast impulse, whereas a liquid layer has no influence on the impulse in the far field. Taking the total impulse due to the blast wave and material impact into account implies that the damage to a nearby structure may actually be augmented for a range of distances. These results should be taken into consideration in the design of explosive mitigant systems.

Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids

NASA Astrophysics Data System (ADS)

Pontalier, Q.; Loiseau, J.; Goroshin, S.; Frost, D. L.

2018-05-01

The attenuation of a blast wave from a high-explosive charge surrounded by a layer of inert material is investigated experimentally in a spherical geometry for a wide range of materials. The blast wave pressure is inferred from extracting the blast wave velocity with high-speed video as well as direct measurements with pressure transducers. The mitigant consists of either a packed bed of particles, a particle bed saturated with water, or a homogeneous liquid. The reduction in peak blast wave overpressure is primarily dependent on the mitigant to explosive mass ratio, M/ C, with the mitigant material properties playing a secondary role. Relative peak pressure mitigation reduces with distance and for low values of M/ C (< 10) can return to unmitigated pressure levels in the mid-to-far field. Solid particles are more effective at mitigating the blast overpressure than liquids, particularly in the near field and at low values of M/ C, suggesting that the energy dissipation during compaction, deformation, and fracture of the powders plays an important role. The difference in scaled arrival time of the blast and material fronts increases with M/ C and scaled distance, with solid particles giving the largest separation between the blast wave and cloud of particles. Surrounding a high-explosive charge with a layer of particles reduces the positive-phase blast impulse, whereas a liquid layer has no influence on the impulse in the far field. Taking the total impulse due to the blast wave and material impact into account implies that the damage to a nearby structure may actually be augmented for a range of distances. These results should be taken into consideration in the design of explosive mitigant systems.

Time-resolved optical measurements of the post-detonation combustion of aluminized explosives

NASA Astrophysics Data System (ADS)

Carney, Joel R.; Miller, J. Scott; Gump, Jared C.; Pangilinan, G. I.

2006-06-01

The dynamic observation and characterization of light emission following the detonation and subsequent combustion of an aluminized explosive is described. The temporal, spatial, and spectral specificity of the light emission are achieved using a combination of optical diagnostics. Aluminum and aluminum monoxide emission peaks are monitored as a function of time and space using streak camera based spectroscopy in a number of light collection configurations. Peak areas of selected aluminum containing species are tracked as a function of time to ascertain the relative kinetics (growth and decay of emitting species) during the energetic event. At the chosen streak camera sensitivity, aluminum emission is observed for 10μs following the detonation of a confined 20g charge of PBXN-113, while aluminum monoxide emission persists longer than 20μs. A broadband optical emission gauge, shock velocity gauge, and fast digital framing camera are used as supplemental optical diagnostics. In-line, collimated detection is determined to be the optimum light collection geometry because it is independent of distance between the optics and the explosive charge. The chosen optical configuration also promotes a constant cylindrical collection volume that should facilitate future modeling efforts.

Numerical modeling of oil shale fragmentation experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuszmaul, J.S.

The economic development of modified in situ oil shale retorting will benefit from the ability to design a blasting scheme that creates a rubble bed of uniform permeability. Preparing such a design depends upon successfully predicting how a given explosive charge and firing sequence will fracture the oil shale. Numerical models are used to predict the extent of damage caused by a particular explosive charge. Recent single-blastwell cratering tests provided experimental measurements of the extent of damage induced by an explosion. Measuring rock damage involved crater excavation, rubble screening, crater elevation surveys, and posttest extraction of cores. These measurements weremore » compared to the damage calculated by the numerical model. Core analyses showed that the damage varied greatly from layer to layer. The numerical results also show this effect, indicating that rock damage is highly dependent on oil shale grade. The computer simulation also calculated particle velocities and dynamic stress amplitudes in the rock; predicted values agree with experimental measurements. Calculated rock fragmentation compared favorably with fragmentation measured by crater excavation and by core analysis. Because coring provides direct inspection of rock fragmentation, the use of posttest coring in future experiments is recommended.« less

Solar + Storage Synergies for Managing Commercial-Customer Demand Charges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagnon, P.; Govindarajan, A.; Bird, L.

Demand charges, which are based on a customer’s maximum demand in kilowatts (kW), are a common element of electricity rate structures for commercial customers. Customer-sited solar photovoltaic (PV) systems can potentially reduce demand charges, but the level of savings is difficult to predict, given variations in demand charge designs, customer loads, and PV generation profiles. Lawrence Berkeley National Laboratory (Berkeley Lab) and the National Renewable Energy Laboratory (NREL) are collaborating on a series of studies to understand how solar PV can impact demand charges. Prior studies in the series examined demand charge reductions from solar on a stand-alone basis formore » residential and commercial customers. Those earlier analyses found that solar, alone, has limited ability to reduce demand charges depending on the specific design of the demand charge and on the shape of the customer’s load profile. This latest analysis estimates demand charge savings from solar in commercial buildings when co-deployed with behind-the-meter storage, highlighting the complementary roles of the two technologies. The analysis is based on simulated loads, solar generation, and storage dispatch across a wide variety of building types, locations, system configurations, and demand charge designs.« less

Remedial action suitability for the Cornhusker Army Ammunition Plant site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nonavinakere, S.; Rappa, P. III

1995-12-31

Numerous Department of Defense (DOD) sites across the nation are contaminated with explosive wastes due to munitions production during World War II, Korean Conflict and Vietnam Conflict. Production activities included explosives manufacturing, loading, packing, assembling, machining, casting and curing. Contaminants often present at these sites include TNT, RDX, HMX, Tetryl 2,4-DNT, 2,6-DNT, 1,3-DNB, 1,3,5-TNB and nitrobenzene. The Cornhusker Army Ammunition Plant (CAAP) is one such DOD site that has been determined to be contaminated with explosives. The CAAP is located approximately 2 miles west of the City of Grand Island in Hall County, Nebraska. The plant produced artillery, bombs, boosters,more » supplementary charges and various other experimental explosives. The purpose of this paper is to provide an overview of the site background, review of the remedial alternatives evaluation process and rationale behind the selection of present remedial action.« less

Explosively driven hypervelocity launcher: Second-stage augmentation techniques

NASA Technical Reports Server (NTRS)

Baum, D. W.

1973-01-01

The results are described of a continuing study aimed at developing a two-stage explosively driven hypervelocity launcher capable of achieving projectile velocities between 15 and 20 km/sec. The testing and evaluation of a new cylindrical impact technique for collapsing the barrel of two-stage launcher are reported. Previous two-stage launchers have been limited in ultimate performance by incomplete barrel collapse behind the projectile. The cylindrical impact technique explosively collapses a steel tube concentric with and surrounding the barrel of the launcher. The impact of the tube on the barrel produces extremely high stresses which cause the barrel to collapse. The collapse rate can be adjusted by appropriate variation of the explosive charge and tubing parameters. Launcher experiments demonstrated that the technique did achieve complete barrel collapse and form a second-stage piston. However, jetting occurred in the barrel collapse process and was responsible for severe projectile damage.

TIMING OF SHOCK WAVES

DOEpatents

Tuck, J.L.

1955-03-01

This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

Optical diagnostics of turbulent mixing in explosively-driven shock tube

NASA Astrophysics Data System (ADS)

Anderson, James; Hargather, Michael

2016-11-01

Explosively-driven shock tube experiments were performed to investigate the turbulent mixing of explosive product gases and ambient air. A small detonator initiated Al / I2O5 thermite, which produced a shock wave and expanding product gases. Schlieren and imaging spectroscopy were applied simultaneously along a common optical path to identify correlations between turbulent structures and spatially-resolved absorbance. The schlieren imaging identifies flow features including shock waves and turbulent structures while the imaging spectroscopy identifies regions of iodine gas presence in the product gases. Pressure transducers located before and after the optical diagnostic section measure time-resolved pressure. Shock speed is measured from tracking the leading edge of the shockwave in the schlieren images and from the pressure transducers. The turbulent mixing characteristics were determined using digital image processing. Results show changes in shock speed, product gas propagation, and species concentrations for varied explosive charge mass. Funded by DTRA Grant HDTRA1-14-1-0070.

Three-phase inductive-coupled structures for contactless PHEV charging system

NASA Astrophysics Data System (ADS)

Lee, Jia-You; Shen, Hung-Yu; Li, Cheng-Bin

2016-07-01

In this article, a new-type three-phase inductive-coupled structure is proposed for the contactless plug-in hybrid electric vehicle (PHEV) charging system regarding with SAE J-1773. Four possible three-phase core structures are presented and subsequently investigated by the finite element analysis. To study the correlation between the core geometric parameter and the coupling coefficient, the magnetic equivalent circuit model of each structure is also established. In accordance with the simulation results, the low reluctance and the sharing of flux path in the core material are achieved by the proposed inductive-coupled structure with an arc-shape and three-phase symmetrical core material. It results in a compensation of the magnetic flux between each phase and a continuous flow of the output power in the inductive-coupled structure. Higher coupling coefficient between inductive-coupled structures is achieved. A comparison of coupling coefficient, mutual inductance, and self-inductance between theoretical and measured results is also performed to verify the proposed model. A 1 kW laboratory scale prototype of the contactless PHEV charging system with the proposed arc-shape three-phase inductive-coupled structure is implemented and tested. An overall system efficiency of 88% is measured when two series lithium iron phosphate battery packs of 25.6 V/8.4 Ah are charged.

Disrupting Improvised Explosive Device Terror Campaigns: Basic Research Opportunities

DTIC Science & Technology

2008-01-01

2008 2. REPORT TYPE 3. DATES COVERED 00-00-2008 to 00-00-2008 4. TITLE AND SUBTITLE Disrupting Improvised Explosive Device Terror Campaigns... Explosive Device Terror Campaigns: Basic Research Opportunities A WORKSHOP REPORT Committee on Defeating Improvised Explosive Devices...iv v COMMITTEE ON DEFEATING IMPROVISED EXPLOSIVE DEVICES: BASIC RESEARCH TO INTERRUPT THE IED DELIVERY CHAIN Chairperson

Production against static electricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shteiner, A.L.; Minaev, G.S.; Shatkov, O.P.

1978-01-01

Coke industry shops process electrifiable, highly inflammable and explosive substances (benzene, toluene, xylenes, sulfur, coal dust, and coke-oven gas). The electrification of those materials creates a danger of buildup of static electricity charges in them and on the surface of objects interacting with them, followed by an electrical discharge which may cause explosion, fire, or disruption of the technological process. Some of the regulations for protection against static electricity do not reflect modern methods of static electricity control. The regulations are not always observed by workers in the plant services. The main means of protection used to remove static electricitymore » charges in grounding. In many cases it completely drains the charge from the surface of the electrifiable bodies. However, in the processing of compounds with a high specific volumetric electrical resistence grounding is insufficient, since it does not drain the charge from the interior of the substance. Gigh adsorption capacity) are generally met by brown coal low-temperature ompared with predictions using the hourly computer program. The concept of a lumped thermal network for predicting heat losses from in-ground heat storage tanks, developed earlier in the project, has beethe cased-hole log data from various companies and additional comparison factors were calculated for the cased-hole log data. These comparison factors allow for some quantification of these uncalibrated log data.« less

Dynamical formation of a Reissner-Nordström black hole with scalar hair in a cavity

NASA Astrophysics Data System (ADS)

Sanchis-Gual, Nicolas; Degollado, Juan Carlos; Herdeiro, Carlos; Font, José A.; Montero, Pedro J.

2016-08-01

In a recent Letter [Sanchis-Gual et al., Phys. Rev. Lett. 116, 141101 (2016)], we presented numerical relativity simulations, solving the full Einstein-Maxwell-Klein-Gordon equations, of superradiantly unstable Reissner-Nordström black holes (BHs), enclosed in a cavity. Low frequency, spherical perturbations of a charged scalar field trigger this instability. The system's evolution was followed into the nonlinear regime, until it relaxed into an equilibrium configuration, found to be a hairy BH: a charged horizon in equilibrium with a scalar field condensate, whose phase is oscillating at the (final) critical frequency. Here, we investigate the impact of adding self-interactions to the scalar field. In particular, we find sufficiently large self-interactions suppress the exponential growth phase, known from linear theory, and promote a nonmonotonic behavior of the scalar field energy. Furthermore, we discuss in detail the influence of the various parameters in this model: the initial BH charge, the initial scalar perturbation, the scalar field charge, the mass, and the position of the cavity's boundary (mirror). We also investigate the "explosive" nonlinear regime previously reported to be akin to a bosenova. A mode analysis shows that the "explosions" can be interpreted as the decay into the BH of modes that exit the superradiant regime.

Spectroscopic characterization of nitroaromatic landmine signature explosives

NASA Astrophysics Data System (ADS)

Hernandez-Rivera, Samuel P.; Manrique-Bastidas, Cesar A.; Blanco, Alejandro; Primera, Oliva M.; Pacheco, Leonardo C.; Castillo-Chara, Jairo; Castro, Miguel E.; Mina, Nairmen

2004-09-01

TNT and DNT are important explosives used as base charges of landmines and other explosive devices. They are often combined with RDX in specific explosive formulations. Their detection in vapor phase as well as in soil in contact with the explosives is important in landmine detection technology. The spectroscopic signatures of nitroaromatic compounds in neat forms: crystals, droplets, and recrystallized samples were determined by Raman Microspectroscopy (RS), Fourier Transform Infrared Microscopy (FTIR) and Fiber Optics Coupled - Fourier Transform Infrared Spectroscopy (FOC-FTIR) using a grazing angle (GA) probe. TNT exhibits a series of characteristic bands: vibrational signatures, which allow its detection in soil. The spectroscopic signature of neat TNT is dominated by strong bands about 1380 and 2970 cm-1. The intensity and position of these bands were found remarkably different in soil samples spiked with TNT. The 1380 cm-1 band is split into a number of bands in that region. The 2970 cm-1 band is reduced in intensity and new bands are observed about 2880 cm-1. The results are consistent with a different chemical environment of TNT in soil as compared to neat TNT. Interactions were found to be dependent on the physical source of the explosive. In the case of DNT-sand interactions, shifts in vibrational frequencies of the explosives as well as the substrates were found.

Feasibility of culvert IED detection using thermal neutron activation

NASA Astrophysics Data System (ADS)

Faust, Anthony A.; McFee, John E.; Clifford, Edward T. H.; Andrews, Hugh Robert; Mosquera, Cristian; Roberts, William C.

2012-06-01

Bulk explosives hidden in culverts pose a serious threat to the Canadian and allied armies. Culverts provide an opportunity to conceal insurgent activity, avoid the need for detectable surface disturbances, and limit the applicability of conventional sub-surface sensing techniques. Further, in spite of the large masses of explosives that can be employed, the large sensor{target separation makes detection of the bulk explosive content challeng- ing. Defence R&D Canada { Sueld and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives for over 15 years. The next generation TNA sensor, known as TNA2, incorporates a number of improvements that allow for increased sensor-to-target dis- tances, making it potentially feasible to detect large improvised explosive devices (IEDs) in culverts using TNA. Experiments to determine the ability of TNA2 to detect improvised explosive devices in culverts are described, and the resulting signal levels observed for relevant quantities of explosives are presented. Observations conrm that bulk explosives detection using TNA against a culvert-IED is possible, with large charges posing a detection challenge at least as dicult as that of a deeply buried anti-tank landmine. Because of the prototype nature of the TNA sensor used, it is not yet possible to make denitive statements about the absolute sensitivity or detection time. Further investigation is warranted.

Multi-dimensional simulations of core-collapse supernova explosions with CHIMERA

NASA Astrophysics Data System (ADS)

Messer, O. E. B.; Harris, J. A.; Hix, W. R.; Lentz, E. J.; Bruenn, S. W.; Mezzacappa, A.

2018-04-01

Unraveling the core-collapse supernova (CCSN) mechanism is a problem that remains essentially unsolved despite more than four decades of effort. Spherically symmetric models with otherwise high physical fidelity generally fail to produce explosions, and it is widely accepted that CCSNe are inherently multi-dimensional. Progress in realistic modeling has occurred recently through the availability of petascale platforms and the increasing sophistication of supernova codes. We will discuss our most recent work on understanding neutrino-driven CCSN explosions employing multi-dimensional neutrino-radiation hydrodynamics simulations with the Chimera code. We discuss the inputs and resulting outputs from these simulations, the role of neutrino radiation transport, and the importance of multi-dimensional fluid flows in shaping the explosions. We also highlight the production of 48Ca in long-running Chimera simulations.

Spherization of the remnants of asymmetrical SN explosions in a uniform medium

NASA Astrophysics Data System (ADS)

Bisnovatyi-Kogan, G. S.; Blinnikov, S. I.

A 'snow-plow' approximation is used to project a spherical shape for a supernova remnant (SNR) after a shock wave has traveled through a uniform medium following an asymmetrical SN explosion. The asymmetry arises as magnetorotation causes the explosion. It is assumed that the main part of the mass remains in a thin layer after the explosion and that the layer can be described by 1,5-dimensional hydrodynamics. The cavity pressure inside the shock is assumed much greater than the pressure of the outside medium. The snow-plow model accounts for asymmetrical particle velocities in the expanding layer and the tangential velocity averaged across the shock. The equations are configured to conserve mass and momentum and have specific initial conditions. The calculations are in agreement with observations of Cas A.

A scheme for the classification of explosions in the chemical process industry.

PubMed

Abbasi, Tasneem; Pasman, H J; Abbasi, S A

2010-02-15

All process industry accidents fall under three broad categories-fire, explosion, and toxic release. Of these fire is the most common, followed by explosions. Within these broad categories occur a large number of sub-categories, each depicting a specific sub-type of a fire/explosion/toxic release. But whereas clear and self-consistent sub-classifications exist for fires and toxic releases, the situation is not as clear vis a vis explosions. In this paper the inconsistencies and/or shortcomings associated with the classification of different types of explosions, which are seen even in otherwise highly authentic and useful reference books on process safety, are reviewed. In its context a new classification is attempted which may, hopefully, provide a frame-of-reference for the future.

Low-mass ions observed in plasma desorption mass spectrometry of high explosives

PubMed

Hakansson; Coorey; Zubarev; Talrose; Hakansson

2000-03-01

The low-mass ions observed in both positive and negative plasma desorption mass spectrometry (PDMS) of the high explosives HMX, RDX, CL-20, NC, PETN and TNT are reported. Possible identities of the most abundant ions are suggested and their presence or absence in the different spectra is related to the properties of the explosives as matrices in PDMS. The detection of abundant NO+ and NO2- ions for HMX, RDX and CL-20, which are efficient matrices, indicates that explosive decomposition takes place in PDMS of these three substances and that a contribution from the corresponding chemical energy release is possible. The observation of abundant C2H4N+ and CH2N+ ions, which have high protonation properties, might also explain the higher protein charge states observed with these matrices. Also, the observation of NO2-, possibly formed by electron scavenging which increases the survival probability of positively charged protein molecular ions, completes the pattern. TNT does not give any of these ions and it is thereby possible to explain why it does not work as a PDMS matrix. For NC and PETN, decomposition does not seem to be as pronounced as for HMX, RDX and CL-20, and also no particularly abundant ions with high protonation properties are observed. The fact that NC works well as a matrix might be related to other properties of this compound, such as its high adsorption ability.

Efficiency Analysis of Waveform Shape for Electrical Excitation of Nerve Fibers

PubMed Central

Wongsarnpigoon, Amorn; Woock, John P.; Grill, Warren M.

2011-01-01

Stimulation efficiency is an important consideration in the stimulation parameters of implantable neural stimulators. The objective of this study was to analyze the effects of waveform shape and duration on the charge, power, and energy efficiency of neural stimulation. Using a population model of mammalian axons and in vivo experiments on cat sciatic nerve, we analyzed the stimulation efficiency of four waveform shapes: square, rising exponential, decaying exponential, and rising ramp. No waveform was simultaneously energy-, charge-, and power-optimal, and differences in efficiency among waveform shapes varied with pulse width (PW) For short PWs (≤ 0.1 ms), square waveforms were no less energy-efficient than exponential waveforms, and the most charge-efficient shape was the ramp. For long PWs (≥0.5 ms), the square was the least energy-efficient and charge-efficient shape, but across most PWs, the square was the most power-efficient shape. Rising exponentials provided no practical gains in efficiency over the other shapes, and our results refute previous claims that the rising exponential is the energy-optimal shape. An improved understanding of how stimulation parameters affect stimulation efficiency will help improve the design and programming of implantable stimulators to minimize tissue damage and extend battery life. PMID:20388602

A luminous, blue progenitor system for the type Iax supernova 2012Z

NASA Astrophysics Data System (ADS)

McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Bildsten, Lars; Fong, Wen-Fai; Kirshner, Robert P.; Marion, G. H.; Riess, Adam G.; Stritzinger, Maximilian D.

2014-08-01

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are `less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

A luminous, blue progenitor system for the type Iax supernova 2012Z.

PubMed

McCully, Curtis; Jha, Saurabh W; Foley, Ryan J; Bildsten, Lars; Fong, Wen-fai; Kirshner, Robert P; Marion, G H; Riess, Adam G; Stritzinger, Maximilian D

2014-08-07

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are 'less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

Summary of Booster Development and Qualification Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francois, Elizabeth G.; Harry, Herbert H.; Hartline, Ernest L.

2012-06-21

This report outlines booster development work done at Los Alamos National Laboratory from 2007 to present. The booster is a critical link in the initiation train of explosive assemblies, from complex devices like nuclear weapons to conventional munitions. The booster bridges the gap from a small, relatively sensitive detonator to an insensitive, but massive, main charge. The movement throughout the explosives development community is to use more and more insensitive explosive components. With that, more energy is needed out of the booster. It has to initiate reliably, promptly, powerfully and safely. This report is divided into four sections. The firstmore » provides a summary of a collaborative effort between LANL, LLNL, and AWE to identify candidate materials and uniformly develop a testing plan for new boosters. Important parameters and the tests required to measure them were defined. The nature of the collaboration and the specific goals of the participating partners has changed over time, but the booster development plan stands on its own merit as a complete description of the test protocol necessary to compare and qualify booster materials, and is discussed in its entirety in this report. The second section describes a project, which began in 2009 with the Department of Defense to develop replacement booster formulations for PBXN-7. Replacement of PBXN-7 was necessary because it contained Triaminotrinitrobenzene (TATB), which was becoming unavailable to the DoD and because it contained Cyclotrimethylenetrinitramine (RDX), which was sensitive and toxic. A LANL-developed explosive, Diaminoazoxyfurazan (DAAF), was an important candidate. This project required any replacement formulation be a drop-in replacement in existing munitions. This project was timely, in that it made use of the collaborative booster development project, and had the additional constraint of matching shock sensitivity. Additionally it needed to be a safety improvement, and a performance improvement, especially at cold temperatures. The requirements of this project necessitated novel test development and a different approach to ranking booster qualities. Results of this project have been documented to the DoD and the relevant portions are included within. The third section of this booster report outlines testing related to main charge initiation merit. Initiability can be evaluated by looking at critical diameter, run distance, and shock sensitivity. Once a booster is initiated, it needs to be powerful enough to initiate the main charge symmetrically and evenly. Main charge initiability is evaluated directly by observing detonation wave symmetry, curvature, and first break out over the surface of a charge. Furthermore it must be insensitive to accidents and insults, and safe and reliable across a range of temperatures. These effects, tests, and results will be discussed individually in the context of DAAF and other explosives similarly tested. The last section provides a conclusion and summary of our experimental work and recommendations for the path forward. References and additional supporting documentation and results are provided in the appendices at the end of this report.« less

A non-imaging polarized terahertz passive system for detecting and identifying concealed explosives

NASA Astrophysics Data System (ADS)

Karam, Mostafa A.; Meyer, Doug

2011-06-01

Existing terahertz THz systems for detecting concealed explosives are not capable of identifying explosive type which leads to higher false alarm rates. Moreover, some of those systems are imaging systems that invade personal privacy, and require more processing and computational resources. Other systems have no polarization preference which makes them incapable of capturing the geometric features of an explosive. In this study a non-imaging polarized THz passive system for detecting and identifying concealed explosives overcoming the forgoing shortcomings is developed. The system employs a polarized passive THz sensor in acquiring emitted data from a scene that may have concealed explosives. The acquired data are decomposed into their natural resonance frequencies, and the number of those frequencies is used as criteria in detecting the explosive presence. If the presence of an explosive is confirmed, a set of physically based retrieval algorithms is used in extracting the explosive dielectric constant/refractive index value from natural resonance frequencies and amplitudes of associated signals. Comparing the refractive index value against a database of refractive indexes of known explosives identifies the explosive type. As an application, a system having a dual polarized radiometer operating within the frequency band of 0.62- 0.82 THz is presented and used in detecting and identifying person borne C-4 explosive concealed under a cotton garment. The system showed higher efficiencies in detecting and identifying the explosive.

Basaltic Diatreme To Root Zone Volcanic Processes In Tuzo Kimberlite Pipe (Gahcho Kué Kimberlite Field, NWT, Canada)

NASA Astrophysics Data System (ADS)

Seghedi, I.; Kurszlaukis, S.; Maicher, D.

2009-05-01

Tuzo pipe is infilled by a series of coherent and fragmental kimberlite facies types typical for a diatreme to root zone transition level. Coherent or transitional coherent kimberlite facies dominate at depth, but also occur at shallow levels, either as dikes or as individual or agglutinated coherent kimberlite clasts (CKC). Several fragmental kimberlite varieties fill the central and shallow portions of the pipe. The definition, geometry and extent of the geological units are complex and are controlled by vertical elements. Specific for Tuzo is: (1) high abundance of locally derived xenoliths (granitoids and minor diabase) between and within the kimberlite phases, varying in size from sub-millimeter to several tens of meters, frequent in a belt-like domain between 120-200 m depth in the pipe; (2) the general presence of CKC, represented by round-subround, irregular to amoeboid-shaped clasts with a macrocrystic or aphanitic texture, mainly derived from fragmentation of erupting magma and less commonly from previously solidified kimberlite, as well as recycled pyroclasts. In addition, some CKC are interpreted to be intersections of a complex dike network. This diversity attests formation by various volcanic processes, extending from intrusive to explosive; (3) the presence of bedded polymict wall- rock and kimberlite breccia occurring mostly in deep levels of the pipe below 345 m depth. The gradational contact relationships of these deposits with the surrounding kimberlite rocks and their location suggest that they formed in situ. The emplacement of Tuzo pipe involved repetitive volcanic explosions alternating with periods of relative quiescence causing at least partial consolidation of some facies. The volume deficit in the diatreme-root zone after each eruption was compensated by gravitational collapse of overlying diatreme tephra and pre-fragmented wall-rock xenoliths. Highly explosive phases were alternating with weak explosions or intrusive phases, suggesting an external factor to control the explosive behaviour of the magma. The overall constant volatile content of the kimberlite does not explain the observed extreme change in emplacement behaviour. The facies architecture of fragmental facies dominated by vertical elements is similar to that in non- kimberlitic diatremes and indicates deposition from debris jets marking separate and repeated explosive volcanic events. In basaltic pipes, such jets are generated by phreatomagmatic explosions in the explosion chamber(s) of the root zone, causing abundant country rock fragmentation and further efficient mixture of the various particles. Phases of high explosivity formed the finely fragmented kimberlites containing a high percentage of wall-rock xenoliths, while the fluidal-shaped and partly welded texturally variable and wall-rock- poor transitional coherent facies suggest phases of repetitive, hot, and low-energy fragmentation forming kimberlite spatter. Peperite hosted in kimberlite tephra is also typically found in basaltic root zones. Time gaps in between volcanic eruptive periods are indicated by cognate pyroclasts and reworked wall-rock deposits emplaced by sporadic sedimentation events in subterranean cavities under the widening roof of the pipe. The presence of temporary caves in the root zone is proposed also by the occurrence of spherical CKC in deep- seated fragmental kimberlite and by spatter found in transitional coherent rocks. Evidence for caves was mostly preserved at deeper pipe levels advocating continuously recurring processes during the life span of Tuzo.

Insights into different Strombolian explosive styles by remote controlled OP-FTIR (CERBERUS) measurements

NASA Astrophysics Data System (ADS)

Spina Alessandro, La; Mike, Burton; Filippo, Murè; Roberto, Maugeri

2014-05-01

In this paper we present the results and interpretation of gas composition data collected by a permanent OP-FTIR system (CERBERUS) installed at Stromboli summit. The instrument allows remote control observation and measurement of gas emissions from different points within volcano's crater terrace, using an integrated infrared camera / scanning mirror / FTIR system. Given that an OpenPath Fourier Transform InfraRed (FTIR) spectrometer allows the simultaneously measure all the major species contained in volcanic gas emissions, we could observe the different explosive styles fed by Stromboli volcano. Stromboli volcano, in the Aeolian island arc, is known as the "Lighthouse of the Mediterranean" for its regular (~every 10-20 min) explosive activity, launching crystal-rich black scoriae to 100-200 m height constituting a rich and impressive spectacle for both volcanologists and tourists from every part of the world. This ordinary activity has been classified in two types in relation to the their content of ash ejected. Type 1 is dominated melt ballistic particles whereas Type 2 consists of an ash-rich plume. On 18 July we recorded both explosive styles at the SW crater of Stromboli finding quite similar CO2/SO2 ratio, although we observed a higher value of SO2/HCl molar ratio for the Type 2. Moreover prior to both types of explosions the CO2 amount showed similar trend, whereas a different pattern in SO2 and in HCl gas content, was observed. In detail type 2 was preceded by decrease in SO2 and HCl amounts with respect to type 1. The decreasing trend observed before the onset of style 2 and the higher SO2/HCl ratio might be an indication of overpressure that might have induced the difference between the two types of explosions. In this context, the evidence of no change in the amount of CO2 and in CO2/SO2 ratio suggested us that this overpressure occurred in very shallow depths within the volcano feeding system. If our observations will be confirmed by other explosive event data, we will be able featuring the different source conditions triggering the ordinary explosive activity at Stromboli.

Improving the accuracy of ultrafast ligand-based screening: incorporating lipophilicity into ElectroShape as an extra dimension.

PubMed

Armstrong, M Stuart; Finn, Paul W; Morris, Garrett M; Richards, W Graham

2011-08-01

In a previous paper, we presented the ElectroShape method, which we used to achieve successful ligand-based virtual screening. It extended classical shape-based methods by applying them to the four-dimensional shape of the molecule where partial charge was used as the fourth dimension to capture electrostatic information. This paper extends the approach by using atomic lipophilicity (alogP) as an additional molecular property and validates it using the improved release 2 of the Directory of Useful Decoys (DUD). When alogP replaced partial charge, the enrichment results were slightly below those of ElectroShape, though still far better than purely shape-based methods. However, when alogP was added as a complement to partial charge, the resulting five-dimensional enrichments shows a clear improvement in performance. This demonstrates the utility of extending the ElectroShape virtual screening method by adding other atom-based descriptors.

Apollo 17 Lunar Surface Experiment equipment

NASA Image and Video Library

1972-11-30

S72-37259 (November 1972) --- The Geophone Module and Cable Reels of the Lunar Seismic Profiling Experiment (S-203), a component of the Apollo Lunar Surface Experiments Package which will be carried on the Apollo 17 lunar landing mission. LSPE components are four geophones similar to those used in an earlier active seismic experiment, an electronics package in the ALSEP central station, and eight explosive packages which will be deployed during the geology traverse. The four geophones will be placed one in the center and one at each corner of a 90-meter equilateral triangle. Explosive charges placed on the surface will generate seismic waves of varying strengths to provide data on the structural profile of the landing site. After the charges have been fired by ground command, the experiment will settle down into a passive listening mode, detecting moonquakes, meteorite impacts and the thump caused by the Lunar Module ascent stage impact.

Fourier Transforms of Pulses Containing Exponential Leading and Trailing Profiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warshaw, S I

2001-07-15

In this monograph we discuss a class of pulse shapes that have exponential rise and fall profiles, and evaluate their Fourier transforms. Such pulses can be used as models for time-varying processes that produce an initial exponential rise and end with the exponential decay of a specified physical quantity. Unipolar examples of such processes include the voltage record of an increasingly rapid charge followed by a damped discharge of a capacitor bank, and the amplitude of an electromagnetic pulse produced by a nuclear explosion. Bipolar examples include acoustic N waves propagating for long distances in the atmosphere that have resultedmore » from explosions in the air, and sonic booms generated by supersonic aircraft. These bipolar pulses have leading and trailing edges that appear to be exponential in character. To the author's knowledge the Fourier transforms of such pulses are not generally well-known or tabulated in Fourier transform compendia, and it is the purpose of this monograph to derive and present these transforms. These Fourier transforms are related to a definite integral of a ratio of exponential functions, whose evaluation we carry out in considerable detail. From this result we derive the Fourier transforms of other related functions. In all Figures showing plots of calculated curves, the actual numbers used for the function parameter values and dependent variables are arbitrary and non-dimensional, and are not identified with any particular physical phenomenon or model.« less

The Shaped Charge Concept. Part 2. The History of Shaped Charges

DTIC Science & Technology

1990-09-01

research of Evans. Ubbel•ode. LAmurd-Jones, Devonihire, and An&ew. 1hW U.K. Mufied cadmium liners (which probably produce molten jets) msd steel liners...34 Mathematical Jet Theory of Lined Hollow Charges." BRL Report No. 370, U.S. Army Ballistic Research Laboratory. Aberdeen Proving Ground, MD, 18 June

Understanding Electrophoresis through the Investigation of Size, Shape, and Charge of pH Indicators

ERIC Educational Resources Information Center

Brenner, Ryan K.; Hess, Kenneth R.; Morford, Jennifer L.

2015-01-01

A laboratory experiment was designed for upper-level students in a Chemical Analysis course to illustrate the theoretical and practical applications of 0.8% agarose gel electrophoresis and to reinforce an understanding of weak acids/bases using easy-to-visualize pH indicators. The careful choice of indicators included acid and base types with…

A supramolecular Tröger's base derived coordination zinc polymer for fluorescent sensing of phenolic-nitroaromatic explosives in water† †Electronic supplementary information (ESI) available: Spectroscopic (multinuclear NMR, IR HRMS) characterizations, optimized structure, TGA, powder diffraction and fluorescence titration profiles. See DOI: 10.1039/c6sc04367d Click here for additional data file.

PubMed Central

Dabadie, Charlyne; Byrne, Kevin; Savyasachi, Aramballi J.; Umadevi, Deivasigamani; Schmitt, Wolfgang; Kitchen, Jonathan A.

2017-01-01

A V-Shaped 4-amino-1,8-napthalimide derived tetracarboxylic acid linker (L; bis-[N-(1,3-benzenedicarboxylic acid)]-9,18-methano-1,8-naphthalimide-[b,f][1,5]diazocine) comprising the Tröger's base (TB) structural motif was rationally designed and synthesised to access a nitrogen-rich fluorescent supramolecular coordination polymer. By adopting the straight forward precipitation method, a new luminescent nanoscale Zn(ii) coordination polymer (TB-Zn-CP) was synthesized in quantitative yield using Zn(OAc)2·2H2O and tetraacid linker L (1 : 0.5) in DMF at room temperature. The phase-purity of as-synthesised TB-Zn-CP was confirmed by X-ray powder diffraction analysis, infra-red spectroscopy, and elemental analysis. Thermogravimetric analysis suggests that TB-Zn-CP is thermally stable up to 330 °C and the morphological features of TB-Zn-CP was analysed by SEM and AFM techniques. The N2 adsorption isotherm of thermally activated TB-Zn-CP at 77 K revealed a type-II reversible adsorption isotherm and the calculated Brunauer–Emmett–Teller (BET) surface area was found to be 72 m2 g–1. Furthermore, TB-Zn-CP displayed an excellent CO2 uptake capacity of 76 mg g–1 at 273 K and good adsorption selectivity for CO2 over N2 and H2. The aqueous suspension of as-synthesized TB-Zn-CP showed strong green fluorescence (λ max = 520 nm) characteristics due to the internal-charge transfer (ICT) transition and was used as a fluorescent sensor for the discriminative sensing of nitroaromatic explosives. The aqueous suspension of TB-Zn-CP showed the largest quenching responses with high selectivity for phenolic-nitroaromatics (4-NP, 2,4-DNP and PA) even in the concurrent presence of other potentially competing nitroaromatic analytes. The fluorescence titration studies also provide evidence that TB-Zn-CP detects picric acid as low as the parts per billion (26.3 ppb) range. Furthermore, the observed fluorescence quenching responses of TB-Zn-CP towards picric acid were highly reversible. The highly selective fluorescence quenching responses including the reversible detection efficiency make the nanoscale coordination polymer TB-Zn-CP a potential material for the discriminative fluorescent sensing of nitroaromatic explosives. PMID:28572910

Mechanically delaminated few layered MoS2 nanosheets based high performance wire type solid-state symmetric supercapacitors

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Karthikeyan; Pazhamalai, Parthiban; Veerasubramani, Ganesh Kumar; Kim, Sang Jae

2016-07-01

Two dimensional nanostructures are increasingly used as electrode materials in flexible supercapacitors for portable electronic applications. Herein, we demonstrated a ball milling approach for achieving few layered molybdenum disulfide (MoS2) via exfoliation from their bulk. Physico-chemical characterizations such as X-ray diffraction, field emission scanning electron microscope, and laser Raman analyses confirmed the occurrence of exfoliated MoS2 sheets with few layers from their bulk via ball milling process. MoS2 based wire type solid state supercapacitors (WSCs) are fabricated and examined using cyclic voltammetry (CV), electrochemical impedance spectroscopy, and galvanostatic charge discharge (CD) measurements. The presence of rectangular shaped CV curves and symmetric triangular shaped CD profiles suggested the mechanism of charge storage in MoS2 WSC is due to the formation of electrochemical double layer capacitance. The MoS2 WSC device delivered a specific capacitance of 119 μF cm-1, and energy density of 8.1 nW h cm-1 with better capacitance retention of about 89.36% over 2500 cycles, which ensures the use of the ball milled MoS2 for electrochemical energy storage devices.

A new type of coil structure called pan-shaped coil of wireless charging system based on magnetic resonance

NASA Astrophysics Data System (ADS)

Yue, Z. K.; Liu, Z. Z.; Hou, Y. J.; Zeng, H.; Liang, L. H.; Cui, S.

2017-11-01

The problem that misalignment between the transmitting coil and the receiving coil significantly impairs the transmission power and efficiency of the system has been attached more and more attention. In order to improve the uniformity of the magnetic field between the two coils to solve this problem, a new type of coil called pan-shaped coil is proposed. Three-dimension simulation models of the planar-core coil and the pan-shaped coil are established using Ansoft Maxwell software. The coupling coefficient between the transmitting coil and the receiving coil is obtained by simulating the magnetic field with the receiving coil misalignment or not. And the maximum percentage difference strength along the radial direction which is defined as the magnetic field uniformity factor is calculated. According to the simulation results of the two kinds of coil structures, it is found that the new type of coil structure can obviously improve the uniformity of the magnetic field, coupling coefficient and power transmission properties between the transmitting coil and the receiving coil.

On the violence of thermal explosion in solid explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chidester, S.K.; Tarver, C.M.; Green, L.G.

Heavily confined cylinders of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and triaminotrinitrobenzene (TATB) were heated at rates varying from 2 C/min to 3.3 C/h. Fourteen of the cylinders were hollow, and inner metallic liners with small heaters attached were used to produce uniform temperatures just prior to explosion. A complex thermocouple pattern was used to measure the temperature history throughout the charge and to determine the approximate location where the runaway exothermic reaction first occurred. The violence of the resulting explosion was measured using velocity pin arrays placed inside and outside of the metal confinement cylinders, flash x-rays, overpressure gauges, and fragment collection techniques.more » Five cylinders were intentionally detonated for violence comparisons. The measured temperature histories, times to explosion, and the locations of first reaction agreed closely with those calculated by a two-dimensional heat transfer code using multistep chemical decomposition models. The acceleration of the confining metal cylinders by the explosion process was accurately simulated using a two-dimensional pressure dependent deflagration reactive flow hydrodynamic mode. The most violent HMX thermal explosions gradually accelerated their outer cases to velocities approaching those of intentional detonations approximately 120 {micro}m after the onset of explosion. The measured inner cylinder collapse velocities from thermal explosions were considerably lower than those produced by detonations. In contrast to the HMX thermal reactions, no violent thermal explosions were produced by the TATB-based explosive LX-17. A heavily confined, slowly heated LX-17 test produced sufficient pressure to cause a 0.1 cm bend in a 2 cm thick steel plate.« less

Effect of surface charge convection and shape deformation on the dielectrophoretic motion of a liquid drop

NASA Astrophysics Data System (ADS)

Mandal, Shubhadeep; Bandopadhyay, Aditya; Chakraborty, Suman

2016-04-01

The dielectrophoretic motion and shape deformation of a Newtonian liquid drop in an otherwise quiescent Newtonian liquid medium in the presence of an axisymmetric nonuniform dc electric field consisting of uniform and quadrupole components is investigated. The theory put forward by Feng [J. Q. Feng, Phys. Rev. E 54, 4438 (1996), 10.1103/PhysRevE.54.4438] is generalized by incorporating the following two nonlinear effects—surface charge convection and shape deformation—towards determining the drop velocity. This two-way coupled moving boundary problem is solved analytically by considering small values of electric Reynolds number (ratio of charge relaxation time scale to the convection time scale) and electric capillary number (ratio of electrical stress to the surface tension) under the framework of the leaky dielectric model. We focus on investigating the effects of charge convection and shape deformation for different drop-medium combinations. A perfectly conducting drop suspended in a leaky (or perfectly) dielectric medium always deforms to a prolate shape and this kind of shape deformation always augments the dielectrophoretic drop velocity. For a perfectly dielectric drop suspended in a perfectly dielectric medium, the shape deformation leads to either increase (for prolate shape) or decrease (for oblate shape) in the dielectrophoretic drop velocity. Both surface charge convection and shape deformation affect the drop motion for leaky dielectric drops. The combined effect of these can significantly increase or decrease the dielectrophoretic drop velocity depending on the electrohydrodynamic properties of both the liquids and the relative strength of the electric Reynolds number and electric capillary number. Finally, comparison with the existing experiments reveals better agreement with the present theory.

Minutes of the Explosives Safety Seminar (24th) Held in St. Louis, Missouri on 28-30 August 1990. Volume 1

DTIC Science & Technology

1990-08-30

concrete-soil-concrete and other soil-filled elements as well as earth embankments of different shapes. The design of the shielding external walls...to vent entirely through the doors. This was required because the large amount of earth fill on the roofs, required for radiation shielding , precluded...Safety Window Shield to Protect Against External Explosions ...... ............... ................... 783 R. L. Shope, W. A. Keenan Strenghtening

Diffraction of Nondiverging Bessel Beams by Fork-Shaped and Rectilinear Grating

NASA Astrophysics Data System (ADS)

Janicijevic, Ljiljana; Topuzoski, Suzana

2007-04-01

We present an investigation about Fresnel diffraction of Bessel beams, propagating as nondiverging within a distance Ln, with or without phase singularities, by rectilinear and fork-shaped gratings. The common general transmission function of these gratings is defined and specialized for three different cases: binary amplitude gratings, amplitude holograms and their phase versions. Solving the Fresnel diffraction integral in cylindrical coordinates, we obtain analytical expressions for the diffracted wave amplitude for all types of proposed gratings, and make conclusions about the existence of phase singularities and corresponding topological charges in the created by the gratings beams of different diffraction orders.

30 CFR 77.1301 - Explosives; magazines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... than 6 feet high. (h) Ammonium nitrate-fuel oil blasting agents shall be physically separated from... explosion hazard. (d) Box-type magazines used to store explosives or detonators in work areas shall be...

Lightning channel current persists between strokes

NASA Astrophysics Data System (ADS)

Wendel, JoAnna

2014-09-01

The usual cloud-to-ground lightning occurs when a large negative charge contained in a "stepped leader" travels down toward the Earth's surface. It then meets a positive charge that comes up tens of meters from the ground, resulting in a powerful neutralizing explosion that begins the first return stroke of the lightning flash. The entire flash lasts only a few hundred milliseconds, but during that time, multiple subsequent stroke-return stroke sequences usually occur.

Cyclic Dinitroureas As Self-Remediating Munition Charges

DTIC Science & Technology

2009-02-26

Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine NAWCWD Naval Air Warfare Center Weapons Division NMR Nuclear magnetic resonance PBXN Plastic Bonded...problems as UXO. A typical submunition fill, such as PBXN -107 in the BLU- 97/B, employs RDX as the main explosive charge. RDX is known to exhibit... 106 ; “maximum lambda” 1050; “lambda factor” 10. Results and Accomplishments As kinetic runs under the various conditions of humidity and soil

Dimensional Analysis of Impulse Loading Resulting from Detonation of Shallow-Buried Charges

DTIC Science & Technology

2013-01-01

lines running along the floor, floor-bolted seats , ammunition storage racks, power-train lines, etc.). MMMS 9,3 368 Traditionally, the floor-rupture...The power of dimensional analysis is that the functional relations offered are generalized, i.e. the effect of geometrical, kinematic , ambient, loading... ejected vdet Explosive detonation velocity L/T A new quantity added which controls the time of sand-overburden bubble burst Charge/plate positioning

Contraction type influences the human ability to use the available torque capacity of skeletal muscle during explosive efforts

PubMed Central

Tillin, Neale A.; Pain, Matthew T. G.; Folland, Jonathan P.

2012-01-01

The influence of contraction type on the human ability to use the torque capacity of skeletal muscle during explosive efforts has not been documented. Fourteen male participants completed explosive voluntary contractions of the knee extensors in four separate conditions: concentric (CON) and eccentric (ECC); and isometric at two knee angles (101°, ISO101 and 155°, ISO155). In each condition, torque was measured at 25 ms intervals up to 150 ms from torque onset, and then normalized to the maximum voluntary torque (MVT) specific to that joint angle and angular velocity. Explosive voluntary torque after 50 ms in each condition was also expressed as a percentage of torque generated after 50 ms during a supramaximal 300 Hz electrically evoked octet in the same condition. Explosive voluntary torque normalized to MVT was more than 60 per cent larger in CON than any other condition after the initial 25 ms. The percentage of evoked torque expressed after 50 ms of the explosive voluntary contractions was also greatest in CON (ANOVA; p < 0.001), suggesting higher concentric volitional activation. This was confirmed by greater agonist electromyography normalized to Mmax (recorded during the explosive voluntary contractions) in CON. These results provide novel evidence that the ability to use the muscle's torque capacity explosively is influenced by contraction type, with concentric contractions being more conducive to explosive performance due to a more effective neural strategy. PMID:22258636

A Distribution-Free Description of Fragmentation by Blasting Based on Dimensional Analysis

NASA Astrophysics Data System (ADS)

Sanchidrián, José A.; Ouchterlony, Finn

2017-04-01

A model for fragmentation in bench blasting is developed from dimensional analysis adapted from asteroid collision theory, to which two factors have been added: one describing the discontinuities spacing and orientation and another the delay between successive contiguous shots. The formulae are calibrated by nonlinear fits to 169 bench blasts in different sites and rock types, bench geometries and delay times, for which the blast design data and the size distributions of the muckpile obtained by sieving were available. Percentile sizes of the fragments distribution are obtained as the product of a rock mass structural factor, a rock strength-to-explosive energy ratio, a bench shape factor, a scale factor or characteristic size and a function of the in-row delay. The rock structure is described by means of the joints' mean spacing and orientation with respect to the free face. The strength property chosen is the strain energy at rupture that, together with the explosive energy density, forms a combined rock strength/explosive energy factor. The model is applicable from 5 to 100 percentile sizes, with all parameters determined from the fits significant to a 0.05 level. The expected error of the prediction is below 25% at any percentile. These errors are half to one-third of the errors expected with the best prediction models available to date.

Quantitative ESD Guidelines for Charged Spacecraft Derived from the Physics of Discharges

NASA Technical Reports Server (NTRS)

Frederickson, A. R.

1992-01-01

Quantitative guidelines are proposed for Electrostatic Discharge (ESD) pulse shape on charged spacecraft. The guidelines are based on existing ground test data, and on a physical description of the pulsed discharge process. The guidelines are designed to predict pulse shape for surface charging and internal charging on a wide variety of spacecraft structures. The pulses depend on the area of the sample, its capacitance to ground, and the strength of the electric field in the vacuum adjacent to the charged surface. By knowing the pulse shape, current vs. time, one can determine if nearby circuits are threatened by the pulse. The quantitative guidelines might be used to estimate the level of threat to an existing spacecraft, or to redesign a spacecraft to reduce its pulses to a known safe level. The experiments which provide the data and the physics that allow one to interpret the data will be discussed, culminating in examples of how to predict pulse shape/size. This method has been used, but not confirmed, on several spacecraft.

Coulomb energy of uniformly charged spheroidal shell systems.

PubMed

Jadhao, Vikram; Yao, Zhenwei; Thomas, Creighton K; de la Cruz, Monica Olvera

2015-03-01

We provide exact expressions for the electrostatic energy of uniformly charged prolate and oblate spheroidal shells. We find that uniformly charged prolate spheroids of eccentricity greater than 0.9 have lower Coulomb energy than a sphere of the same area. For the volume-constrained case, we find that a sphere has the highest Coulomb energy among all spheroidal shells. Further, we derive the change in the Coulomb energy of a uniformly charged shell due to small, area-conserving perturbations on the spherical shape. Our perturbation calculations show that buckling-type deformations on a sphere can lower the Coulomb energy. Finally, we consider the possibility of counterion condensation on the spheroidal shell surface. We employ a Manning-Oosawa two-state model approximation to evaluate the renormalized charge and analyze the behavior of the equilibrium free energy as a function of the shell's aspect ratio for both area-constrained and volume-constrained cases. Counterion condensation is seen to favor the formation of spheroidal structures over a sphere of equal area for high values of shell volume fractions.

Fast neutron sensor for detection of explosives and chemical warfare agents.

PubMed

Valkovic, Vladivoj; Sudac, Davorin; Matika, Dario

2010-01-01

Once the presence of the anomaly on the bottom of the shallow coastal sea water has been confirmed it is necessary to establish if it contains explosive or chemical warfare charge. We propose that this be performed by using neutron sensor installed within an underwater vessel. When positioned above the object, or to its side, the system can inspect the object for the presence of the threat materials by using alpha particle tagged neutrons from the sealed tube d+t neutron generator. Copyright 2009 Elsevier Ltd. All rights reserved.

Transparent Tube Studies of Burning to Detonation Transition in Granular Explosives 1: Preliminary Framing Camera Studies

DTIC Science & Technology

1980-10-27

Reference 13. The 94/6 RDX/ wax (X893) and 97/3 RDX/ wax (X758) were mechanical mixtures prepared from Class A RDX (X597) and carnauba wax (N134). The...UKLAS9*TE SE,’CRITY CLASSIFICATION OF THIS PAGE (When Data Entered) ionization probes in previous steel tube studies. In charges of 94/6 RDX/ wax ...explosives (picric acid, tetryl, and RDX/ wax ) were among those materials in previous steel tube studies at NSWC which achieved deflagration to

Foundations and Earth Structures. Design Manual 7.2

DTIC Science & Technology

1982-05-01

Cairo only) I FT27 (: daho Falls only) 2 39E 7 FH25 MPhilndelphia, Portsmouth 1 712B I 42A3 VA, Camp Lejeune, Oakland, 4 FT31 4 453B Newport;, Great...8217 > 3 " 2 --5 - 1 2 3 5 7 10 20 30 5070 100 200 EXAMPLE: - Weight of Explosive Charge 8 lbs. - W Distance from Blast Point - 100 ft. - R4 R/(W)-/3 50...power. Explosives ............ Drill and blast ahead of pile tip a. To remove obstructions to open end piles under very severe conditions

A transient semimetallic layer in detonating nitromethane

NASA Astrophysics Data System (ADS)

Reed, Evan J.; Riad Manaa, M.; Fried, Laurence E.; Glaesemann, Kurt R.; Joannopoulos, J. D.

2008-01-01

Despite decades of research, the microscopic details and extreme states of matter found within a detonating high explosive have yet to be elucidated. Here we present the first quantum molecular-dynamics simulation of a shocked explosive near detonation conditions. We discover that the wide-bandgap insulator nitromethane (CH3NO2) undergoes chemical decomposition and a transformation into a semimetallic state for a limited distance behind the detonation front. We find that this transformation is associated with the production of charged decomposition species and provides a mechanism to explain recent experimental observations.

Impact initiation of explosives and propellants via statistical crack mechanics

NASA Astrophysics Data System (ADS)

Dienes, J. K.; Zuo, Q. H.; Kershner, J. D.

2006-06-01

A statistical approach has been developed for modeling the dynamic response of brittle materials by superimposing the effects of a myriad of microcracks, including opening, shear, growth and coalescence, taking as a starting point the well-established theory of penny-shaped cracks. This paper discusses the general approach, but in particular an application to the sensitivity of explosives and propellants, which often contain brittle constituents. We examine the hypothesis that the intense heating by frictional sliding between the faces of a closed crack during unstable growth can form a hot spot, causing localized melting, ignition, and fast burn of the reactive material adjacent to the crack. Opening and growth of a closed crack due to the pressure of burned gases inside the crack and interactions of adjacent cracks can lead to violent reaction, with detonation as a possible consequence. This approach was used to model a multiple-shock experiment by Mulford et al. [1993. Initiation of preshocked high explosives PBX-9404, PBX-9502, PBX-9501, monitored with in-material magnetic gauging. In: Proceedings of the 10th International Detonation Symposium, pp. 459-467] involving initiation and subsequent quenching of chemical reactions in a slab of PBX 9501 impacted by a two-material flyer plate. We examine the effects of crack orientation and temperature dependence of viscosity of the melt on the response. Numerical results confirm our theoretical finding [Zuo, Q.H., Dienes, J.K., 2005. On the stability of penny-shaped cracks with friction: the five types of brittle behavior. Int. J. Solids Struct. 42, 1309-1326] that crack orientation has a significant effect on brittle behavior, especially under compressive loading where interfacial friction plays an important role. With a reasonable choice of crack orientation and a temperature-dependent viscosity obtained from molecular dynamics calculations, the calculated particle velocities compare well with those measured using embedded velocity gauges.

No neurochemical evidence of brain injury after blast overpressure by repeated explosions or firing heavy weapons.

PubMed

Blennow, K; Jonsson, M; Andreasen, N; Rosengren, L; Wallin, A; Hellström, P A; Zetterberg, H

2011-04-01

Psychiatric and neurological symptoms are common among soldiers exposed to blast without suffering a direct head injury. It is not known whether such symptoms are direct consequences of blast overpressure. To examine if repeated detonating explosions or firing if of heavy weapons is associated with neurochemical evidence of brain damage. Three controlled experimental studies. In the first, army officers were exposed to repeated firing of a FH77B howitzer or a bazooka. Cerebrospinal fluid (CSF) was taken post-exposure to measure biomarkers for brain damage. In the second, officers were exposed for up to 150 blasts by firing a bazooka, and in the third to 100 charges of detonating explosives of 180 dB. Serial serum samples were taken after exposure. Results were compared with a control group consisting of 19 unexposed age-matched healthy volunteers. The CSF biomarkers for neuronal/axonal damage (tau and neurofilament protein), glial cell injury (GFAP and S-100b), blood-brain barrier damage (CSF/serum albumin ratio) and hemorrhages (hemoglobin and bilirubin) and the serum GFAP and S-100b showed normal and stable levels in all exposed officers. Repeated exposure to high-impact blast does not result in any neurochemical evidence of brain damage. These findings are of importance for soldiers regularly exposed to high-impact blast when firing artillery shells or other types of heavy weapons. © 2010 John Wiley & Sons A/S.

46 CFR 10.229 - Issuance of duplicate merchant mariner credentials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... replaced credential(s). The duplicate issued will be in the form of an MMC. Until April 15, 2014, if a... charge. The term “other casualty” includes any damage to a ship caused by collision, explosion, tornado...

46 CFR 10.229 - Issuance of duplicate merchant mariner credentials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... replaced credential(s). The duplicate issued will be in the form of an MMC. Until April 15, 2014, if a... charge. The term “other casualty” includes any damage to a ship caused by collision, explosion, tornado...

Multi-dimensional simulations of core-collapse supernova explosions with CHIMERA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Messer, Bronson; Harris, James Austin; Hix, William Raphael

Unraveling the core-collapse supernova (CCSN) mechanism is a problem that remains essentially unsolved despite more than four decades of effort. Spherically symmetric models with otherwise high physical fidelity generally fail to produce explosions, and it is widely accepted that CCSNe are inherently multi-dimensional. Progress in realistic modeling has occurred recently through the availability of petascale platforms and the increasing sophistication of supernova codes. We will discuss our most recent work on understanding neutrino-driven CCSN explosions employing multi-dimensional neutrino-radiation hydrodynamics simulations with the Chimera code. We discuss the inputs and resulting outputs from these simulations, the role of neutrino radiation transport,more » and the importance of multi-dimensional fluid flows in shaping the explosions. We also highlight the production of 48Ca in long-running Chimera simulations.« less

Microstructural change in electroformed copper liners of shaped charges upon plastic deformation at ultra-high strain rate

NASA Astrophysics Data System (ADS)

Tian, W. H.; Hu, S. L.; Fan, A. L.; Wang, Z.

2002-01-01

Transmission electron microscopy (TEM) observations were carried out for examining the as-formed and post-deformed microstructures in a variety of electroformed copper liners of shaped charges. The deformation was carried out at an ultra-high strain rate. Specifically, the electron backscattering Kikuchi pattern (EBSP) technique was utilized to examine the micro-texture of these materials. TEM observations revealed that these electroformed copper liners of shaped charges have a grain size of about 1-3 mum, EBSP analysis demonstrated that the as-grown copper liners of shaped charges exhibit a l 10) fiber micro-texture which is parallel to the normal direction of the surface of the liners of shaped charges. Having undergone plastic deformation at ultra-high strain rate (10(7) s(-1)), the specimens which were recovered from the copper slugs were found to have grain size of the same order as that before deformation. EBSP analysis revealed that the (110) fiber texture existed in the as-formed copper liners disappears in the course of deformation. TEM examination results indicate that dynamic recovery and recrystallization play a significant role in this deformation process.

Investigating Degassing in Felsic and Mafic Magmas by 3-D Imaging of Vesicle Pathways

NASA Astrophysics Data System (ADS)

Polacci, M.; Baker, D. R.; Piochi, M.; Mancini, L.

2009-12-01

Volatiles are the motor of volcanic eruptions. Studies of vesiculation in erupted products can provide information on how volatiles exsolve, grow and are lost from magmas as lava and tephra fragments bear the fingerprints of such processes in vesicle and crystal textures. We summarize here the results of a series of X-ray computed microtomographic experiments that were performed on about 70 volcanic specimens of mainly basaltic and trachytic compositions. A first sample suite comprises samples collected from explosive activity at persistently degassing basaltic volcanoes, namely Stromboli (Aeolian Islands), Etna (Eastern Sicily) and Ambrym (Vanuatu Islands); a second suite consists of pumice and scoria clasts from Plinian to Subplinian to Vulcanian eruptions that occurred in the Campi Flegrei caldera (Southern Italy). The tomographic images provide us with a complete 3-D view of our sampled material through which it is possible to reconstruct the geometry of the vesicle network and explore how gas was transported in the investigated magmas. We find that basaltic scoriae exhibit two types of vesicles: large (~ mm^3), coalescing vesicles with complex, convoluted shapes and small-to-intermediate sized (<~1x10^-3 mm^3), spherical to sub-spherical, poorly connected or isolated vesicles. The former vesicles were interpreted as percolation pathways for gas to flow non-explosively to the volcano crater and thought to sustain the persistent passive gas release that characterizes these volcanoes. The fact that such vesicles were found in products erupted from active basaltic volcanoes located in different tectonic settings and characterized by different explosivity strongly suggests that basaltic systems appear to follow a common degassing pathway. However, not all explosive basaltic rocks contain large, coalescing vesicles. Pumice clasts from the much more violent, dangerous and less frequent paroxysmal explosions at Stromboli do not have this type of vesicles, demonstrating that basaltic volcanoes develop different vesicle textures and therefore degassing dynamics with increasing explosive activity. Trachytic pumices from highly explosive eruptions display a much finer structure in comparison to scoriae having sub-spherical to slightly deformed large vesicles and a large population of small spherical vesicles (1x10^-3 - <1x10^-5 mm^3). These two vesicle textures were mainly ascribed to the rapid ascent of a supersaturated magma under closed-system degassing, in comparison to the open-system conditions of basaltic magmas. Large interconnected vesicles that form micro-cracks are, however, found in some denser pyroclasts from Campi Flegrei. This suggests that gas was percolating in the conduit system before the eruption and that open-system degassing may be an effective way through which gas is lost in a moderately violent manner at the crater surface in some explosive felsic eruptions. Ultimately this study reveals that 3-D imaging of volcanic rocks is an essential tool for investigating degassing conditions in erupted magmas.

Development of multi-component explosive lenses for arbitrary phase velocity generation

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Huneault, Justin; Petel, Oren; Goroshin, Sam; Frost, David; Higgins, Andrew; Zhang, Fan

2013-06-01

The combination of explosives with different detonation velocities and lens-like geometric shaping is a well-established technique for producing structured detonation waves. This technique can be extended to produce nearly arbitrary detonation phase velocities for the purposes of sequentially imploding pressurized tubes or driving Mach disks through high-density metalized explosives. The current study presents the experimental development of accelerating, multi-component lenses designed using simple geometric optics and idealized front curvature. The fast explosive component is either Composition C4 (VOD = 8 km/s) or Primasheet 1000 (VOD = 7 km/s), while the slow component varies from heavily amine-diluted nitromethane (amine mass fraction exceeding 20%) to packed metal and glass particle beds wetted with amine-sensitized nitromethane. The applicability of the geometric optic analog to such highly heterogeneous explosives is also investigated. The multi-layered lens technique is further developed as a means of generating a directed mass and momentum flux of metal particles via Mach-disk formation and jetting in circular and oval planar lenses.

Plasma parameters of the cathode spot explosive electron emission cell obtained from the model of liquid-metal jet tearing and electrical explosion

NASA Astrophysics Data System (ADS)

Tsventoukh, M. M.

2018-05-01

A model has been developed for the explosive electron emission cell pulse of a vacuum discharge cathode spot that describes the ignition and extinction of the explosive pulse. The pulse is initiated due to hydrodynamic tearing of a liquid-metal jet which propagates from the preceding cell crater boundary and draws the ion current from the plasma produced by the preceding explosion. Once the jet neck has been resistively heated to a critical temperature (˜1 eV), the plasma starts expanding and decreasing in density, which corresponds to the extinction phase. Numerical and analytical solutions have been obtained that describe both the time behavior of the pulse plasma parameters and their average values. For the cell plasma, the momentum per transferred charge has been estimated to be some tens of g cm/(s C), which is consistent with the known measurements of ion velocity, ion erosion rate, and specific recoil force. This supports the model of the pressure-gradient-driven plasma acceleration mechanism for the explosive cathode spot cells. The ohmic electric field within the explosive current-carrying plasma has been estimated to be some tens of kV/cm, which is consistent with the known experimental data on cathode potential fall and explosive cell plasma size. This supports the model that assumes the ohmic nature of the cathode potential fall in a vacuum discharge.

Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite.

PubMed

Gunawan, Richard; Zhang, Dongke

2009-06-15

The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol(-1) and 4.55 x 10(7)s(-1) without the presence of pyrite and 101.8 kJ mol(-1) and 2.57 x 10(9)s(-1) with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments.

Green primaries: Environmentally friendly energetic complexes

PubMed Central

Huynh, My Hang V.; Hiskey, Michael A.; Meyer, Thomas J.; Wetzler, Modi

2006-01-01

Primary explosives are used in small quantities to generate a detonation wave when subjected to a flame, heat, impact, electric spark, or friction. Detonation of the primary explosive initiates the secondary booster or main-charge explosive or propellant. Long-term use of lead azide and lead styphnate as primary explosives has resulted in lead contamination at artillery and firing ranges and become a major health hazard and environmental problem for both military and civilian personnel. Devices using lead primary explosives are manufactured by the tens of millions every year in the United States from primers for bullets to detonators for mining. Although substantial synthetic efforts have long been focused on the search for greener primary explosives, this unresolved problem has become a “holy grail” of energetic materials research. Existing candidates suffer from instability or excessive sensitivity, or they possess toxic metals or perchlorate. We report here four previously undescribed green primary explosives based on complex metal dianions and environmentally benign cations, (cat)2[MII(NT)4(H2O)2] (where cat is NH4+ or Na+, M is Fe2+ or Cu2+, and NT− is 5-nitrotetrazolato-N2). They are safer to prepare, handle, and transport than lead compounds, have comparable initiation efficiencies to lead azide, and offer rapid reliable detonation comparable with lead styphnate. Remarkably, they possess all current requirements for green primary explosives and are suitable to replace lead primary explosives in detonators. More importantly, they can be synthesized more safely, do not pose health risks to personnel, and cause much less pollution to the environment. PMID:16567623

Optically stimulated luminescence and thermoluminescence efficiencies for high-energy heavy charged particle irradiation in Al2O3:C.

PubMed

Yukihara, E G; Gaza, R; McKeever, S W S; Soares, C G

2004-02-01

The thermally and optically stimulated luminescence (TL and OSL) response to high energy heavy-charged particles (HCPs) was investigated for two types of Al2O3:C luminescence dosimeters. The OSL signal was measured in both continuous-wave (CW) and pulsed mode. The efficiencies of the HCPs at producing TL or OSL, relative to gamma radiation, were obtained using four different HCPs beams (150 MeV/u 4He, 400 MeV/u 12C, 490 MeV/u 28Si, and 500 MeV/u 56Fe). The efficiencies were determined as a function of the HCP linear energy transfer (LET). It was observed that the efficiency depends on the type of detector, measurement technique, and the choice of signal. Additionally, it is shown that the shape of the CW-OSL decay curve from Al2O3:C depends on the type of radiation, and, in principle, this can be used to extract information concerning the LET of an unknown radiation field. The response of the dosimeters to low-LET radiation was also investigated for doses in the range from about 1-1000 Gy. These data were used to explain the different efficiency values obtained for the different materials and techniques, as well as the LET dependence of the CW-OSL decay curve shape. c2003 Elsevier Ltd. All rights reserved.

Optically stimulated luminescence and thermoluminescence efficiencies for high-energy heavy charged particle irradiation in Al2O3:C

NASA Technical Reports Server (NTRS)

Yukihara, E. G.; Gaza, R.; McKeever, S. W. S.; Soares, C. G.

2004-01-01

The thermally and optically stimulated luminescence (TL and OSL) response to high energy heavy-charged particles (HCPs) was investigated for two types of Al2O3:C luminescence dosimeters. The OSL signal was measured in both continuous-wave (CW) and pulsed mode. The efficiencies of the HCPs at producing TL or OSL, relative to gamma radiation, were obtained using four different HCPs beams (150 MeV/u 4He, 400 MeV/u 12C, 490 MeV/u 28Si, and 500 MeV/u 56Fe). The efficiencies were determined as a function of the HCP linear energy transfer (LET). It was observed that the efficiency depends on the type of detector, measurement technique, and the choice of signal. Additionally, it is shown that the shape of the CW-OSL decay curve from Al2O3:C depends on the type of radiation, and, in principle, this can be used to extract information concerning the LET of an unknown radiation field. The response of the dosimeters to low-LET radiation was also investigated for doses in the range from about 1-1000 Gy. These data were used to explain the different efficiency values obtained for the different materials and techniques, as well as the LET dependence of the CW-OSL decay curve shape. c2003 Elsevier Ltd. All rights reserved.

Planned Destruction of Metal-Core Reactor: Simulation of Catastrophic Accidents and New Experimental Possibilities

NASA Astrophysics Data System (ADS)

Vorontsov, S. V.; Kuvshinov, M. I.; Narozhnyi, A. T.; Popov, V. A.; Solov'ev, V. P.; Yuferev, V. I.

2017-12-01

A reactor with a destructible core (RIR reactor) generating a pulse with an output of 1.5 × 1019 fissions and a full width at half maximum of 2.5 μs was developed and tested at VNIIEF. In the course of investigation, a computational-experimental method for laboratory calibration of the reactor was created and worked out. This method ensures a high accuracy of predicting the energy release in a real experiment with excess reactivity of 3βeff above prompt criticality. A transportable explosion-proof chamber was also developed, which ensures the safe localization of explosion products of the core of small-sized nuclear devices and charges of high explosives with equivalent mass of up to 100 kg of TNT.

Trace Detection of RDX, HMX and PETN Explosives Using a Fluorescence Spot Sensor

PubMed Central

Wang, Chen; Huang, Helin; Bunes, Benjamin R.; Wu, Na; Xu, Miao; Yang, Xiaomei; Yu, Li; Zang, Ling

2016-01-01

1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and pentaerythritol tetranitrate (PETN), the major components in plastic explosives, pose a significant threat to public safety. A quick, sensitive, and low-cost detection method for these non-volatile explosives is eagerly demanded. Here we present a fluo-spot approach, which can be employed for in situ detection of trace amount of explosives. The sensor molecule is a charge-transfer fluorophore, DCM, which is strongly fluorescent in its pristine state, but non-fluorescent after the quick reaction with NO2· (or NO2+) generated from the UV photolysis of RDX, HMX (or PETN). When fabricated within silica gel TLC plate, the fluo-spot sensor features high sensitivity owing to the large surface area and porous structure of the substrate. The sensor reaction mechanism was verified by various experimental characterizations, including chromatography, UV-Vis absorption and fluorescence spectroscopy, MS and 1H NMR spectrometry. The fluo-spot also demonstrated high selectivity towards RDX, HMX and PETN, as no significant fluorescence quenching was observed for other chemical compounds including common nitro-aromatic explosives and inorganic oxidative compounds. The DCM sensor can also be used as an economical spray kit to directly spot the explosives by naked eyes, implying great potential for quick, low-cost trace explosives detection. PMID:27146290

Trace Detection of RDX, HMX and PETN Explosives Using a Fluorescence Spot Sensor.

PubMed

Wang, Chen; Huang, Helin; Bunes, Benjamin R; Wu, Na; Xu, Miao; Yang, Xiaomei; Yu, Li; Zang, Ling

2016-05-05

1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and pentaerythritol tetranitrate (PETN), the major components in plastic explosives, pose a significant threat to public safety. A quick, sensitive, and low-cost detection method for these non-volatile explosives is eagerly demanded. Here we present a fluo-spot approach, which can be employed for in situ detection of trace amount of explosives. The sensor molecule is a charge-transfer fluorophore, DCM, which is strongly fluorescent in its pristine state, but non-fluorescent after the quick reaction with NO2· (or NO2(+)) generated from the UV photolysis of RDX, HMX (or PETN). When fabricated within silica gel TLC plate, the fluo-spot sensor features high sensitivity owing to the large surface area and porous structure of the substrate. The sensor reaction mechanism was verified by various experimental characterizations, including chromatography, UV-Vis absorption and fluorescence spectroscopy, MS and (1)H NMR spectrometry. The fluo-spot also demonstrated high selectivity towards RDX, HMX and PETN, as no significant fluorescence quenching was observed for other chemical compounds including common nitro-aromatic explosives and inorganic oxidative compounds. The DCM sensor can also be used as an economical spray kit to directly spot the explosives by naked eyes, implying great potential for quick, low-cost trace explosives detection.

EHD Approach to Tornadic Thunderstorms and Methods of Their Destruction

NASA Astrophysics Data System (ADS)

Kikuchi, H.

2005-05-01

In many cases, tornadoes are accompanied or involved by lightning discharges and are thought to be com- posed of uncharged and charged components different from each other in terms of velocity, vorticity, heli- city, and appearance (shape and luminosity). Their visible dark portion may correspond to uncharged tor- nadoes, while luminous or bright part may involve charged tornadoes with return strokes. Usually, un- charged tornadoes have been considered to be ascending hot streams of thermohydrodynamic origin. This is the conventional theory of tornadoes, based on hydrodynamics (HD) or thermohydrodynamics (THD) but does not consider electrical effects that are really significant in tornadic thunderstorms..It has been shown, however, that a new electrohydrodynamics (EHD) established and developed over the last more than a decade is applicable to tornadic thunderstorms with lightning. This paper summarizes such an EHD approach and proposes the methods of tornado destruction based on EHD. Space charge and electric field configurations in tornadic thunderstorms are considered to be quadrupole-like, taking into account the cloud-charge images onto the ground. Accordingly, dynamics of particles and EHD flows in an electric quadrupole forming an electric cusp and mirror can straightly apply to those circumstances. When the gas pressure is below the breakdown threshold, there occur helical motion of particles, not only charged but also even uncharged, and/or vortex generation. While for gases whose pressure is beyond the breakdown threshold, the following basic processes succeed one after another. When the grain is uncharged, a dis- charge channel is formed towards each pole as a result of X-type reconnection. For a negatively or posi- tively charged grain, I-type reconnection occurs between the grain and positive or negative poles, respect- ively. For uncharged two grains, O-type reconnection between both grains could be involved in addition to X-type between each pole, while for oppositely charged two grains, F-type reconnection could be in- volved between grains in addition to I-type between each grain and a pole with opposite polarity. Thus one can say that the uncharged component of tornadic thunderstorms is composed of conventional ascending hot streams of thermohydrodynamic origin and particle flows of new EHD origin produced by a quadru- pole-like cloud-base, funnel-top charge distributions, while the charged component is a bunch of return strokes including charged flows due to dust-related electric reconnection and EHD vortices in large-scale generated by EHD helical turbulence where there may occur self-organization to coalescence of fluid vor- tex and electric displacement field lines at least in an initial stage of return stroke (rise time of some ms), since earth's magnetic field could be ignored. This also indicates that fluid vortex breakdown points also tend to merge electric cusps, X-type and O-type. Then the principle of dust-related electric reconnection could be replaced by dust cluster injection into electric cusps (X-type and O-type) in several ways just mentioned above. Thus a variety of such dust cluster injection could cause additional cloud-to-dust cluster discharges, expending electrostatic energy accumulated in thunderclouds considerably and destructing tornadoes consequently.

The Explosive Spherical Cavity Expansion for Characterization of SiC-N Ceramic Dynamic Behavior and Post Shock Damage Using RUS Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gefken, Paul; Curran, Donald; Nesterenko, Vitali F.

Two spherical cavity expansion experiments were performed with SiC-N to provide high-strain rate data for developing ceramic armor penetration models. Here, an explosive charge is detonated within a cavity machined in the ceramic, generating a pulse that moves radially outward. The particle velocity at multiple radial locations from the charge, including at the charge radii, was measured and the fractured ceramic was recovered for posttest evaluation. From the particle velocity histories we derived displacement, radial strain and circumferential strain histories. In the recovered samples we observed the regions where comminution, radial cracking and circumferential cracking occurred. The elastic properties ofmore » initial undamaged SiC-N and shocked damaged material were measured using a resonant ultrasound spectroscopy (RUS). Comparison of these measurements illustrated the posttest condition of the SiC-N material. Hot isostatic pressing of ''as is'' SiC-N material demonstrated a significant increase in the quality factor. The same procedure applied to SiC-N damaged in spherical cavity experiments resulted in a significant recovery of the elastic properties.« less

Influencing Factors of the Initiation Point in the Parachute-Bomb Dynamic Detonation System

NASA Astrophysics Data System (ADS)

Qizhong, Li; Ye, Wang; Zhongqi, Wang; Chunhua, Bai

2017-12-01

The parachute system has been widely applied in modern armament design, especially for the fuel-air explosives. Because detonation of fuel-air explosives occurs during flight, it is necessary to investigate the influences of the initiation point to ensure successful dynamic detonation. In fact, the initiating position exist the falling area in the fuels, due to the error of influencing factors. In this paper, the major influencing factors of initiation point were explored with airdrop and the regularity between initiation point area and factors were obtained. Based on the regularity, the volume equation of initiation point area was established to predict the range of initiation point in the fuel. The analysis results showed that the initiation point appeared area, scattered on account of the error of attitude angle, secondary initiation charge velocity, and delay time. The attitude angle was the major influencing factors on a horizontal axis. On the contrary, secondary initiation charge velocity and delay time were the major influencing factors on a horizontal axis. Overall, the geometries of initiation point area were sector coupled with the errors of the attitude angle, secondary initiation charge velocity, and delay time.

Maturing CCD Photon-Counting Technology for Space Flight

NASA Technical Reports Server (NTRS)

Mallik, Udayan; Lyon, Richard; Petrone, Peter; McElwain, Michael; Benford, Dominic; Clampin, Mark; Hicks, Brian

2015-01-01

This paper discusses charge blooming and starlight saturation - two potential technical problems - when using an Electron Multiplying Charge Coupled Device (EMCCD) type detector in a high-contrast instrument for imaging exoplanets. These problems especially affect an interferometric type coronagraph - coronagraphs that do not use a mask to physically block starlight in the science channel of the instrument. These problems are presented using images taken with a commercial Princeton Instrument EMCCD camera in the Goddard Space Flight Center's (GSFC), Interferometric Coronagraph facility. In addition, this paper discusses techniques to overcome such problems. This paper also discusses the development and architecture of a Field Programmable Gate Array and Digital-to-Analog Converter based shaped clock controller for a photon-counting EMCCD camera. The discussion contained here will inform high-contrast imaging groups in their work with EMCCD detectors.

Rare Isotopes in Cosmic Explosions and Accelerators on Earth

ScienceCinema

Schatz, Hendrick

2017-12-28

Rare isotopes are nature’s stepping stones to produce the heavy elements, and they are produced in large quantities in stellar explosions. Despite their fleeting existence, they shape the composition of the universe and the observable features of stellar explosions. The challenge for nuclear science is to produce and study the very same rare isotopes so as to understand the origin of the elements and a range of astronomical observations. I will review the progress that has been made to date in astronomy and nuclear physics, and the prospects of finally addressing many of the outstanding issues with the future Facility for Rare Isotope Beams (FRIB), which DOE will build at Michigan State University.

Demonstration of Lightweight Engineering Solutions for a Low-Cost Safe Explosive Ordnance Destruct Tool

DTIC Science & Technology

2007-12-01

Staff) and Mr. Doug Learned ( Intercity Manufacturing), whose efficiency and expertise was vital in manufacturing the parts required for our tests...detonation products caused by the hollow cavity. Upon initiation of a hollow lined charge, the resulting high pressure shock wave travels outward...5.6 km/s for the brass encased charge at 2 and 3 CD. This indicates that the jet must be traveling at velocities greater than the estimates, which

Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs

DTIC Science & Technology

2013-03-01

sample. Light from the fiber optics was sent to spectrograph located in a shielded observation room several meters away from the explosive charge. The...spectrograph was constructed from a 1/8 m spectrometer (Oriel) interfaced to a 4096 pixel line-scan camera (Basler Sprint ) with a data collection rate... 400 ) 45 4000 (200) … FIG. 3. Time-resolved emission spectra obtained from detonation of 20 g charges of RDX containing 20 wt. % aluminum nanoparticles

Collection of trace evidence of explosive residues from the skin in a death due to a disguised letter bomb. The synergy between confocal laser scanning microscope and inductively coupled plasma atomic emission spectrometer analyses.

PubMed

Turillazzi, Emanuela; Monaci, Fabrizio; Neri, Margherita; Pomara, Cristoforo; Riezzo, Irene; Baroni, Davide; Fineschi, Vittorio

2010-04-15

In most deaths caused by explosive, the victim's body becomes a depot for fragments of explosive materials, so contributing to the collection of trace evidence which may provide clues about the specific type of device used with explosion. Improvised explosive devices are used which contain "homemade" explosives rather than high explosives because of the relative ease with which such components can be procured. Many methods such as chromatography-mass spectrometry, scanning electron microscopy, stereomicroscopy, capillary electrophoresis are available for use in the identification of explosive residues on objects and bomb fragments. Identification and reconstruction of the distribution of explosive residues on the decedent's body may give additional hints in assessing the position of the victim in relation to the device. Traditionally these residues are retrieved by swabbing the body and clothing during the early phase, at autopsy. Gas chromatography-mass spectrometry and other analytical methods may be used to analyze the material swabbed from the victim body. The histological examination of explosive residues on skin samples collected during the autopsy may reveal significant details. The information about type, quantity and particularly about anatomical distribution of explosive residues obtained utilizing confocal laser scanning microscope (CLSM) together with inductively coupled plasma atomic emission spectrometer (ICP-AES), may provide very significant evidence in the clarification and reconstruction of the explosive-related events. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

The propulsive capability of explosives heavily loaded with inert materials

NASA Astrophysics Data System (ADS)

Loiseau, J.; Georges, W.; Frost, D. L.; Higgins, A. J.

2018-01-01

The effect of inert dilution on the accelerating ability of high explosives for both grazing and normal detonations was studied. The explosives considered were: (1) neat, amine-sensitized nitromethane (NM), (2) packed beds of glass, steel, or tungsten particles saturated with amine-sensitized NM, (3) NM gelled with PMMA containing dispersed glass microballoons, (4) NM gelled with PMMA containing glass microballoons and steel particles, and (5) C-4 containing varying mass fractions of glass or steel particles. Flyer velocity was measured via photonic Doppler velocimetry, and the results were analysed using a Gurney model augmented to include the influence of the diluent. Reduction in accelerating ability with increasing dilution for the amine-sensitized NM, gelled NM, and C-4 was measured experimentally. Variation of flyer terminal velocity with the ratio of flyer mass to charge mass (M/C) was measured for both grazing and normally incident detonations in gelled NM containing 10% microballoons by mass and for steel beads saturated with amine-sensitized NM. Finally, flyer velocity was measured in grazing versus normal loading for a number of explosive admixtures. The augmented Gurney model predicted the effect of dilution on accelerating ability and the scaling of flyer velocity with M/C for mixtures containing low-density diluents. The augmented Gurney model failed to predict the scaling of flyer velocity with M/C for mixtures heavily loaded with dense diluents. In all cases, normally incident detonations propelled flyers to higher velocity than the equivalent grazing detonations because of material velocity imparted by the incident shock wave and momentum/energy transfer from the slapper used to uniformly initiate the charge.

The propulsive capability of explosives heavily loaded with inert materials

NASA Astrophysics Data System (ADS)

Loiseau, J.; Georges, W.; Frost, D. L.; Higgins, A. J.

2018-07-01

The effect of inert dilution on the accelerating ability of high explosives for both grazing and normal detonations was studied. The explosives considered were: (1) neat, amine-sensitized nitromethane (NM), (2) packed beds of glass, steel, or tungsten particles saturated with amine-sensitized NM, (3) NM gelled with PMMA containing dispersed glass microballoons, (4) NM gelled with PMMA containing glass microballoons and steel particles, and (5) C-4 containing varying mass fractions of glass or steel particles. Flyer velocity was measured via photonic Doppler velocimetry, and the results were analysed using a Gurney model augmented to include the influence of the diluent. Reduction in accelerating ability with increasing dilution for the amine-sensitized NM, gelled NM, and C-4 was measured experimentally. Variation of flyer terminal velocity with the ratio of flyer mass to charge mass ( M/ C) was measured for both grazing and normally incident detonations in gelled NM containing 10% microballoons by mass and for steel beads saturated with amine-sensitized NM. Finally, flyer velocity was measured in grazing versus normal loading for a number of explosive admixtures. The augmented Gurney model predicted the effect of dilution on accelerating ability and the scaling of flyer velocity with M/ C for mixtures containing low-density diluents. The augmented Gurney model failed to predict the scaling of flyer velocity with M/ C for mixtures heavily loaded with dense diluents. In all cases, normally incident detonations propelled flyers to higher velocity than the equivalent grazing detonations because of material velocity imparted by the incident shock wave and momentum/energy transfer from the slapper used to uniformly initiate the charge.

Resource recycling technique of abandoned TNT-RDX-AL mixed explosive

NASA Astrophysics Data System (ADS)

Chen, Siyang; Ding, Yukui

2017-08-01

TNT-RDX-AL mixed explosive is a kind of high energy mixed explosive. It has the detonation characteristics even when reaching the scrapping standard. Inappropriate disposal often causes serious accident. Employing the resource recycling technique, the abandoned TNT-RDX-AL mixed explosive can be recycled. This paper summarized the progress of recycling of abandoned mixed explosive. What's more, three kinds of technological process of resource recycling abandoned TNT-RDX-AL mixed explosives are introduced. The author analysis of the current recovery processes and provided a reference for the recycling of the other same type explosive.

Distribution of Ejecta in Analog Tephra Rings from Discrete Single and Multiple Subsurface Explosions

NASA Astrophysics Data System (ADS)

Graettinger, A. H.; Valentine, G. A.; Sonder, I.; Ross, P. S.; White, J. D. L.

2015-12-01

Buried-explosion experiments were used to investigate the spatial and volumetric distribution of extra-crater ejecta resulting from a range of explosion configurations with and without a crater present. Explosion configuration is defined in terms of scaled depth, the relationship between depth of burial and the cube root of explosion energy, where an optimal scaled depth explosion produces the largest crater diameter for a given energy. The multiple explosion experiments provide an analog for the formation of maar-diatreme ejecta deposits and the deposits of discrete explosions through existing conduits and hydrothermal systems. Experiments produced meter-sized craters with ejecta distributed between three major facies based on morphology and distance from the crater center. The proximal deposits form a constructional steep-sided ring that extends no more than two-times the crater radius away from center. The medial deposits form a low-angle continuous blanket that transitions with distance into the isolated clasts of the distal ejecta. Single explosion experiments produce a trend of increasing volume proportion of proximal ejecta as scaled depth increases (from 20-90% vol.). Multiple explosion experiments are dominated by proximal deposits (>90% vol.) for all but optimal scaled depth conditions (40-70% vol.). In addition to scaled depth, the presence of a crater influences jet shape and how the jet collapses, resulting in two end-member depositional mechanisms that produce distinctive facies. The experiments use one well-constrained explosion mechanism and, consequently, the variations in depositional facies and distribution are the result of conditions independent of that mechanism. Previous interpretations have invoked variations in fragmentation as the cause of this variability, but these experiments should help with a more complete reconstruction of the configuration and number of explosions that produce a tephra ring.

Effectiveness of quality-control aids in verifying K-9-team explosive detection performance

NASA Astrophysics Data System (ADS)

Hallowell, Susan F.; Fischer, Douglas S.; Brasher, Jeffrey D.; Malone, Robert L.; Gresham, Garold L.; Rae, Cathy

1997-02-01

The Federal Aviation Administration (FAA) and supporting agencies conducted a developmental test and evaluation (DTE) to determine if quality control aids (QCAs) could be developed that would provide effective surrogates to actual explosives used for training and testing K-9 explosives detection teams. Non-detonable surrogates are required to alleviate logistics and contamination issues with explosives used sa training aids. Comparative K-9 team detection performance for explosives used as training aids and QCAs configurations of each explosive type were evaluated to determine the optimal configuration for the QCA configuration of each explosive type were evaluated to determine the optimal configuration for the QCAs. The configurations were a paper patch impregnated with a solution of the explosive, a cloth pouch filed with small amounts of solid explosive, and the non-hazardous explosive for security training and testing material. The DTE was conducted at Lackland Air Force Base in San Antonio, Texas, where the K-9 teams undergo initial training. Six FAA certified operational teams participated. All explosives and QCAs were presented to the K-9 teams using a 10 scent box protocol. The results show that K-9 team as are more sensitive to explosives than the candidate QCAs. More importantly, it was discovered that the explosives at Lackland AFB are cross-contaminated, meaning that explosives possessed volatile artifacts from other explosives. There are two potential hypotheses explaining why the dogs did not detect the QCAs. First, the cross-contamination of Lackland training explosives may mean that K-9 teams are only trained to detect the explosives with the most volatile chemical signatures. Alternatively, the QCA configurations may have been below the trained detection threshold of the K-9s. It is recommended that K-9 teams train on uncontaminated odors from properly designed QCAs to ensure that dogs respond to the appropriate explosive components, and not some other constituent or contaminant.

Molecular dynamics simulation of Coulomb explosion, melting and shock wave creation in silicon after an ionization pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhongyu; Shao, Lin, E-mail: lshao@tamu.edu; Chen, Di

Strong electronic stopping power of swift ions in a semiconducting or insulating substrate can lead to localized electron stripping. The subsequent repulsive interactions among charged target atoms can cause Coulomb explosion. Using molecular dynamics simulation, we simulate Coulomb explosion in silicon by introducing an ionization pulse lasting for different periods, and at different substrate temperatures. We find that the longer the pulse period, the larger the melting radius. The observation can be explained by a critical energy density model assuming that melting required thermal energy density is a constant value and the total thermal energy gained from Coulomb explosion ismore » linearly proportional to the ionization period. Our studies also show that melting radius is larger at higher substrate temperatures. The temperature effect is explained due to a longer structural relaxation above the melting temperature at original ionization boundary due to lower heat dissipation rates. Furthermore, simulations show the formation of shock waves, created due to the compression from the melting core.« less