Insensitive explosive composition and method of fracturing rock using an extrudable form of the composition

DOEpatents

Davis, Lloyd L.

2015-07-28

Insensitive explosive compositions were prepared by reacting di-isocyanate and/or poly-isocyanate monomers with an explosive diamine monomer. Prior to a final cure, the compositions are extrudable. The di-isocyanate monomers tend to produce tough, rubbery materials while polyfunctional monomers (i.e. having more than two isocyanate groups) tend to form rigid products. The extrudable form of the composition may be used in a variety of applications including rock fracturing.

Development of explosively bonded TZM wire reinforced Columbian sheet composites

NASA Technical Reports Server (NTRS)

Otto, H. E.; Carpenter, S. H.

1972-01-01

Methods of producing TZM molybdenum wire reinforced C129Y columbium alloy composites by explosive welding were studied. Layers of TZM molybdenum wire were wound on frames with alternate layers of C129Y columbium alloy foil between the wire layers. The frames held both the wire and foils in place for the explosive bonding process. A goal of 33 volume percent molybdenum wire was achieved for some of the composites. Variables included wire diameter, foil thickness, wire separation, standoff distance between foils and types and amounts of explosive. The program was divided into two phases: (1) development of basic welding parameters using 5 x 10-inch composites, and (2) scaleup to 10 x 20-inch composites.

Explosive composition with group VIII metal nitroso halide getter

DOEpatents

Walker, Franklin E.; Wasley, Richard J.

1982-01-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm.sup.2 or less of energy fluence.

Explosive composition with group VIII metal nitroso halide getter

DOEpatents

Walker, F.E.; Wasley, R.J.

1982-06-22

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm[sup 2] or less of energy fluence.

Effect of Velocity of Detonation of Explosives on Seismic Radiation

NASA Astrophysics Data System (ADS)

Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

2014-12-01

We studied seismic body wave generation from four fully contained explosions of approximately the same yields (68 kg of TNT equivalent) conducted in anisotropic granite in Barre, VT. The explosions were detonated using three types of explosives with different velocities of detonation (VOD): Black Powder (BP), Ammonium Nitrate Fuel Oil/Emulsion (ANFO), and Composition B (COMP B). The main objective of the experiment was to study differences in seismic wave generation among different types of explosives, and to determine the mechanism responsible for these differences. The explosives with slow burn rate (BP) produced lower P-wave amplitude and lower corner frequency, which resulted in lower seismic efficiency (0.35%) in comparison with high burn rate explosives (2.2% for ANFO and 3% for COMP B). The seismic efficiency estimates for ANFO and COMP B agree with previous studies for nuclear explosions in granite. The body wave radiation pattern is consistent with an isotropic explosion with an added azimuthal component caused by vertical tensile fractures oriented along pre-existing micro-fracturing in the granite, although the complexities in the P- and S-wave radiation patterns suggest that more than one fracture orientation could be responsible for their generation. High S/P amplitude ratios and low P-wave amplitudes suggest that a significant fraction of the BP source mechanism can be explained by opening of the tensile fractures as a result of the slow energy release.

Thermal Explosion Violence of HMX-Based and RDX-Based Explosives - Effects of Composition, Confinement, and Solid Phase Using the Scaled Thermal Explosion Experiment

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

Maienschein, J L; Wardell, J F

The Scaled Thermal Explosion Experiment (STEX) has been developed to quantify the violence of thermal explosion under well defined and carefully controlled initial and boundary conditions. Here we present results with HMX-based explosives (LX-04 and PBX-9501) and with Composition B. Samples are 2 inches (50 mm) in diameter and 8 inches (200 mm) in length, under confinement of 7,500-30,000 psi (50-200 MPa), with heating rates of 1-3 C/hr. We quantify reaction violence by measuring the wall velocity in the ensuing thermal explosion, and relate the measured velocity to that expected from a detonation. Results with HMX-based explosives (LX-04 and PBX-9501)more » have shown the importance of confinement and HMX solid phase, with reaction violence ranging from mild pressure bursts to near detonations. By contrast, Composition B has shown very violent reactions over a wide range of conditions.« less

Theoretical Investigation of Calculating Temperatures in the Combining Zone of Cu/Fe Composite Plate Jointed by Explosive Welding

NASA Astrophysics Data System (ADS)

Qu, Y. D.; Zhang, W. J.; Kong, X. Q.; Zhao, X.

2016-03-01

The heat-transfer behavior of the interface of Flyer plate (or Base Plate) has great influence on the microcosmic structures, stress distributions, and interface distortion of the welded interface of composite plates by explosive welding. In this paper, the temperature distributions in the combing zone are studied for the case of Cu/Fe composite plate jointed by explosive welding near the lower limit of explosive welding. The results show that Flyer plate (Cu plate) and Base Plate (Fe plate) firstly almost have the same melting rate in the explosive welding process. Then, the melting rate of Cu plate becomes higher than that of Fe plate. Finally, the melt thicknesses of Cu plate and Fe plate trend to be different constants, respectively. Meanwhile, the melting layer of Cu plate is thicker than that of Fe plate. The research could supply some theoretical foundations for calculating the temperature distribution and optimizing the explosive welding parameters of Cu/Fe composite plate to some extent.

Zirconium hydride containing explosive composition

DOEpatents

Walker, Franklin E.; Wasley, Richard J.

1981-01-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a donor additive comprising a non-explosive compound or mixture of non-explosive compounds which when subjected to an energy fluence of 1000 calories/cm.sup.2 or less is capable of releasing free radicals each having a molecular weight between 1 and 120. Exemplary donor additives are dibasic acids, polyamines and metal hydrides.

Free radical explosive composition

DOEpatents

Walker, Franklin E.; Wasley, Richard J.

1979-01-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a getter additive comprising a compound or mixture of compounds capable of capturing or deactivating free radicals or ions under mechanical or electrical shock conditions and which is not an explosive. Exemplary getter additives are isocyanates, olefins and iodine.

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

Campbell, Keri; Judge, Elizabeth J.; Dirmyer, Matthew R.

Surrogate nuclear explosive debris was synthesized and characterized for major, minor, and trace elemental composition as well as uranium isotopics. The samples consisted of an urban glass matrix, equal masses soda lime and cement, doped with 500 ppm uranium with varying enrichments. The surface and cross section morphology were measured with SEM, and the major elemental composition was determined by XPS. LA-ICP-MS was used to measure the uranium isotopic abundance comparing different sampling techniques. Furthermore, the results provide an example of the utility of LA-ICP-MS for forensics applications.

Bayesian Integration and Classification of Composition C-4 Plastic Explosives Based on Time-of-Flight-Secondary Ion Mass Spectrometry and Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

PubMed

Mahoney, Christine M; Kelly, Ryan T; Alexander, Liz; Newburn, Matt; Bader, Sydney; Ewing, Robert G; Fahey, Albert J; Atkinson, David A; Beagley, Nathaniel

2016-04-05

Time-of-flight-secondary ion mass spectrometry (TOF-SIMS) and laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) were used for characterization and identification of unique signatures from a series of 18 Composition C-4 plastic explosives. The samples were obtained from various commercial and military sources around the country. Positive and negative ion TOF-SIMS data were acquired directly from the C-4 residue on Si surfaces, where the positive ion mass spectra obtained were consistent with the major composition of organic additives, and the negative ion mass spectra were more consistent with explosive content in the C-4 samples. Each series of mass spectra was subjected to partial least squares-discriminant analysis (PLS-DA), a multivariate statistical analysis approach which serves to first find the areas of maximum variance within different classes of C-4 and subsequently to classify unknown samples based on correlations between the unknown data set and the original data set (often referred to as a training data set). This method was able to successfully classify test samples of C-4, though with a limited degree of certainty. The classification accuracy of the method was further improved by integrating the positive and negative ion data using a Bayesian approach. The TOF-SIMS data was combined with a second analytical method, LA-ICPMS, which was used to analyze elemental signatures in the C-4. The integrated data were able to classify test samples with a high degree of certainty. Results indicate that this Bayesian integrated approach constitutes a robust classification method that should be employable even in dirty samples collected in the field.

Preparation and characterization of polyaniline-copper composites by electrical explosion of wire.

PubMed

Liu, Aijie; Bac, Luong Huu; Kim, Jin-Chun; Liu, Lizhu

2012-07-01

Polyaniline-copper composites with a polyacrylic acid (PAA) were synthesized by electrical explosion of wire. Polyaniline (PANI) and PAA were put into the explosion medium, deionized water (DIW) and ethanol, stirred for 24 hrs and sonicated for 2 hrs. These solutions were used as base liquids for explosion process to fabricate Cu nanoparticle. Optical absorption in the UV-visible region of PANI and PANI/PAA-Cu composites was measured in a range of 200-900 nm. X-ray diffraction was used to analyze the phase of the composites. XRD pattern showed the PANI was amorphous and copper was polycrystalline. Two phases of Cu and Cu2O were formed in aqueous solution while single Cu phase was obtained in ethanol solution. Field emission scanning electron microscope was used to observe the microstructure of the composites. The synthesized composites were extensively characterized by Fourier Transform Infrared (FTIR) spectroscopy and electrical measurements.

Dye@bio-MOF-1 Composite as a Dual-Emitting Platform for Enhanced Detection of a Wide Range of Explosive Molecules.

PubMed

Wang, Chen; Tian, Li; Zhu, Wei; Wang, Shiqiang; Wang, Peng; Liang, Yun; Zhang, Wanlin; Zhao, Hongwei; Li, Guangtao

2017-06-14

By incorporating a cationic dye within a metal-organic framework (MOF) through an ion-exchange process, a responsive dye@bio-MOF-1 composite has been synthesized, serving as a dual-emitting platform for enhanced detection of different kinds of nitro-explosives, especially nitroalkanes, nitramines, and nitrate esters. The dye@bio-MOF-1 composite was constructed with free amines on their well-defined cavities, which is essential for the capture of explosives into their confined nanospace. It was observed that the encapsulation of explosives into the constructed dye@bio-MOF-1 composite could dramatically alter the luminescent properties of the dyes as well as the MOF skeletons owing to the size exclusivity and confinement-induced effect. For nitroaromatics, the dye@bio-MOF-1 composite exhibits turn-off responses via fluorescence quenching. Unexpectedly, the composite shows unique turn-on responses for aliphatic nitro-organics via confinement-induced enhancement, demonstrating enhanced ability to detecting different kinds of explosives selectively in aqueous solution. Furthermore, the dye@bio-MOF-1 film was facilely fabricated, making the chemical sensing more convenient and easier to realize the discrimination of the targeted explosives. The dual tunable responses indicate that dye@bio-MOF-1 composites are favorable materials for molecular sensing. On the basis of the host-guest properties of the constructed dye@bio-MOF-1 composite, our work can be further extended to sensing specific analytes with remarkable turn-on sensing properties, in particular those difficult to recognize with conventional methods.

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.

Computer code for the optimization of performance parameters of mixed explosive formulations.

PubMed

Muthurajan, H; Sivabalan, R; Talawar, M B; Venugopalan, S; Gandhe, B R

2006-08-25

LOTUSES is a novel computer code, which has been developed for the prediction of various thermodynamic properties such as heat of formation, heat of explosion, volume of explosion gaseous products and other related performance parameters. In this paper, we report LOTUSES (Version 1.4) code which has been utilized for the optimization of various high explosives in different combinations to obtain maximum possible velocity of detonation. LOTUSES (Version 1.4) code will vary the composition of mixed explosives automatically in the range of 1-100% and computes the oxygen balance as well as the velocity of detonation for various compositions in preset steps. Further, the code suggests the compositions for which least oxygen balance and the higher velocity of detonation could be achieved. Presently, the code can be applied for two component explosive compositions. The code has been validated with well-known explosives like, TNT, HNS, HNF, TATB, RDX, HMX, AN, DNA, CL-20 and TNAZ in different combinations. The new algorithm incorporated in LOTUSES (Version 1.4) enhances the efficiency and makes it a more powerful tool for the scientists/researches working in the field of high energy materials/hazardous materials.

Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

NASA Astrophysics Data System (ADS)

Malyutina, Yu. N.; Bataev, A. A.; Mali, V. I.; Anisimov, A. G.; Shevtsova, L. I.

2015-10-01

A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

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

Malyutina, Yu. N., E-mail: iuliiamaliutina@gmail.com; Bataev, A. A., E-mail: bataev@adm.nstu.ru; Shevtsova, L. I., E-mail: edeliya2010@mail.ru

A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

Effect of Heat Treatment on Mechanical Properties and Phase Composition of Magnesium-Aluminum Composite Prepared by Explosive Welding

NASA Astrophysics Data System (ADS)

Arisova, V. N.; Trykov, Yu. P.; Slautin, O. V.; Ponomareva, I. A.; Kondakov, A. E.

2015-09-01

Results are given for a study of the effect of heat treatment regimes on the nature of change in micromechanical properties and phase composition of magnesium-aluminum composite material AD1-MA2-1 prepared by explosive welding.

Petrologic constraints on the decompression history of magma prior to Vulcanian explosions at the Soufrière Hills volcano, Montserrat

NASA Astrophysics Data System (ADS)

Clarke, A. B.; Stephens, S.; Teasdale, R.; Sparks, R. S. J.; Diller, K.

2007-04-01

A series of 88 Vulcanian explosions occurred at the Soufrière Hills volcano, Montserrat, between August and October, 1997. Conduit conditions conducive to creating these and other Vulcanian explosions were explored via analysis of eruptive products and one-dimensional numerical modeling of magma ascent through a cylindrical conduit. The number densities and textures of plagioclase microlites were documented for twenty-three samples from the events. The natural samples all show very high number densities of microlites, and > 50% by number of microlites have areas < 20 μm 2. Pre-explosion conduit conditions and decompression history have been inferred from these data by comparison with experimental decompressions of similar groundmass compositions. Our comparisons suggest quench pressures < 30 MPa (origin depths < 2 km) and multiple rapid decompressions of > 13.75 MPa each during ascent from chamber to surface. Values are consistent with field studies of the same events and statistical analysis of explosion time-series data. The microlite volume number density trend with depth reveals an apparent transition from growth-dominated crystallization to nucleation-dominated crystallization at pressures of ˜ 7 MPa and lower. A concurrent sharp increase in bulk density marks the onset of significant open-system degassing, apparently due to a large increase in system permeability above ˜ 70% vesicularity. This open-system degassing results in a dense plug which eventually seals the conduit and forms conditions favorable to Vulcanian explosions. The corresponding inferred depth of overpressure at 250-700 m, near the base of the dense plug, is consistent with depth to center of pressure estimated from deformation measurements. Here we also illustrate that one-dimensional models representing ascent of a degassing, crystal-rich magma are broadly consistent with conduit profiles constructed via our petrologic analysis. The comparison between models and petrologic data suggests that the dense conduit plug forms as a result of high overpressure and open-system degassing through conduit walls.

Cycles of explosive and effusive eruptions at Kīlauea Volcano, Hawai‘i

USGS Publications Warehouse

Swanson, Don; Rose, Timothy R.; Mucek, Adonara E; Garcia, Michael O.; Fiske, Richard S.; Mastin, Larry G.

2014-01-01

The subaerial eruptive activity at Kīlauea Volcano (Hawai‘i) for the past 2500 yr can be divided into 3 dominantly effusive and 2 dominantly explosive periods, each lasting several centuries. The prevailing style of eruption for 60% of this time was explosive, manifested by repeated phreatic and phreatomagmatic activity in a deep summit caldera. During dominantly explosive periods, the magma supply rate to the shallow storage volume beneath the summit dropped to only a few percent of that during mainly effusive periods. The frequency and duration of explosive activity are contrary to the popular impression that Kīlauea is almost unceasingly effusive. Explosive activity apparently correlates with the presence of a caldera intersecting the water table. The decrease in magma supply rate may result in caldera collapse, because erupted or intruded magma is not replaced. Glasses with unusually high MgO, TiO2, and K2O compositions occur only in explosive tephra (and one related lava flow) and are consistent with disruption of the shallow reservoir complex during caldera formation. Kīlauea is a complex, modulated system in which melting rate, supply rate, conduit stability (in both mantle and crust), reservoir geometry, water table, and many other factors interact with one another. The hazards associated with explosive activity at Kīlauea’s summit would have major impact on local society if a future dominantly explosive period were to last several centuries. The association of lowered magma supply, caldera formation, and explosive activity might characterize other basaltic volcanoes, but has not been recognized.

Investigation of the Microstructural, Mechanical and Corrosion Properties of Grade A Ship Steel-Duplex Stainless Steel Composites Produced via Explosive Welding

NASA Astrophysics Data System (ADS)

Kaya, Yakup; Kahraman, Nizamettin; Durgutlu, Ahmet; Gülenç, Behçet

2017-08-01

Grade A ship-building steel-AISI 2304 duplex stainless steel composite plates were manufactured via explosive welding. The AISI 2304 plates were used to clad the Grade A plates. Optical microscopy studies were conducted on the joining interface for characterization of the manufactured composite plates. Notch impact, tensile-shear, microhardness, bending and twisting tests were carried out to determine the mechanical properties of the composites. In addition, the surfaces of fractured samples were examined by scanning electron microscopy (SEM), and neutral salt spray (NSS) and potentiodynamic polarization tests were performed to examine corrosion behavior. Near the explosion zone, the interface was completely flat, but became wavy as the distance from the explosion zone increased. The notch impact tests indicated that the impact strength of the composites decreased with increasing distance from the explosion zone. The SEM studies detected brittle behavior below the impact transition temperature and ductile behavior above this temperature. Microhardness tests revealed that the hardness values increased with increasing distance from the explosion zone and mechanical tests showed that no visible cracking or separation had occurred on the joining interface. The NSS and potentiodynamic polarization tests determined that the AISI 2304 exhibited higher corrosion resistance than the Grade A steel.

Printable sensors for explosive detonation

NASA Astrophysics Data System (ADS)

Griffith, Matthew J.; Cooling, Nathan A.; Elkington, Daniel C.; Muller, Elmar; Belcher, Warwick J.; Dastoor, Paul C.

2014-10-01

Here, we report the development of an organic thin film transistor (OTFT) based on printable solution processed polymers and employing a quantum tunnelling composite material as a sensor to convert the pressure wave output from detonation transmission tubing (shock tube) into an inherently amplified electronic signal for explosives initiation. The organic electronic detector allows detection of the signal in a low voltage operating range, an essential feature for sites employing live ordinances that is not provided by conventional electronic devices. We show that a 30-fold change in detector response is possible using the presented detector assembly. Degradation of the OTFT response with both time and repeated voltage scans was characterised, and device lifetime is shown to be consistent with the requirements for on-site printing and usage. The integration of a low cost organic electronic detector with inexpensive shock tube transmission fuse presents attractive avenues for the development of cheap and simple assemblies for precisely timed initiation of explosive chains.

Underwater explosive compaction-sintering of tungsten-copper coating on a copper surface

NASA Astrophysics Data System (ADS)

Chen, Xiang; Li, Xiaojie; Yan, Honghao; Wang, Xiaohong; Chen, Saiwei

2018-01-01

This study investigated underwater explosive compaction-sintering for coating a high-density tungsten-copper composite on a copper surface. First, 50% W-50% Cu tungsten-copper composite powder was prepared by mechanical alloying. The composite powder was pre-compacted and sintered by hydrogen. Underwater explosive compaction was carried out. Finally, a high-density tungsten-copper coating was obtained by diffusion sintering of the specimen after explosive compaction. A simulation of the underwater explosive compaction process showed that the peak value of the pressure in the coating was between 3.0 and 4.8 GPa. The hardness values of the tungsten-copper layer and the copper substrate were in the range of 87-133 and 49 HV, respectively. The bonding strength between the coating and the substrate was approximately 100-105 MPa.

A compositional tipping point governing the mobilization and eruption style of rhyolitic magma

NASA Astrophysics Data System (ADS)

di Genova, D.; Kolzenburg, S.; Wiesmaier, S.; Dallanave, E.; Neuville, D. R.; Hess, K. U.; Dingwell, D. B.

2017-12-01

The most viscous volcanic melts and the largest explosive eruptions on our planet consist of calcalkaline rhyolites. These eruptions have the potential to influence global climate. The eruptive products are commonly very crystal-poor and highly degassed, yet the magma is mostly stored as crystal mushes containing small amounts of interstitial melt with elevated water content. It is unclear how magma mushes are mobilized to create large batches of eruptible crystal-free magma. Further, rhyolitic eruptions can switch repeatedly between effusive and explosive eruption styles and this transition is difficult to attribute to the rheological effects of water content or crystallinity. Here we measure the viscosity of a series of melts spanning the compositional range of the Yellowstone volcanic system and find that in a narrow compositional zone, melt viscosity increases by up to two orders of magnitude. These viscosity variations are not predicted by current viscosity models and result from melt structure reorganization, as confirmed by Raman spectroscopy. We identify a critical compositional tipping point, independently documented in the global geochemical record of rhyolites, at which rhyolitic melts fluidize or stiffen and that clearly separates effusive from explosive deposits worldwide. This correlation between melt structure, viscosity and eruptive behaviour holds despite the variable water content and other parameters, such as temperature, that are inherent in natural eruptions. Thermodynamic modelling demonstrates how the observed subtle compositional changes that result in fluidization or stiffening of the melt can be induced by crystal growth from the melt or variation in oxygen fugacity. However, the rheological effects of water and crystal content alone cannot explain the correlation between composition and eruptive style. We conclude that the composition of calcalkaline rhyolites is decisive in determining the mobilization and eruption dynamics of Earth’s largest volcanic systems, resulting in a better understanding of how the melt structure controls volcanic processes.

A compositional tipping point governing the mobilization and eruption style of rhyolitic magma.

PubMed

Di Genova, D; Kolzenburg, S; Wiesmaier, S; Dallanave, E; Neuville, D R; Hess, K U; Dingwell, D B

2017-12-13

The most viscous volcanic melts and the largest explosive eruptions on our planet consist of calcalkaline rhyolites. These eruptions have the potential to influence global climate. The eruptive products are commonly very crystal-poor and highly degassed, yet the magma is mostly stored as crystal mushes containing small amounts of interstitial melt with elevated water content. It is unclear how magma mushes are mobilized to create large batches of eruptible crystal-free magma. Further, rhyolitic eruptions can switch repeatedly between effusive and explosive eruption styles and this transition is difficult to attribute to the rheological effects of water content or crystallinity. Here we measure the viscosity of a series of melts spanning the compositional range of the Yellowstone volcanic system and find that in a narrow compositional zone, melt viscosity increases by up to two orders of magnitude. These viscosity variations are not predicted by current viscosity models and result from melt structure reorganization, as confirmed by Raman spectroscopy. We identify a critical compositional tipping point, independently documented in the global geochemical record of rhyolites, at which rhyolitic melts fluidize or stiffen and that clearly separates effusive from explosive deposits worldwide. This correlation between melt structure, viscosity and eruptive behaviour holds despite the variable water content and other parameters, such as temperature, that are inherent in natural eruptions. Thermodynamic modelling demonstrates how the observed subtle compositional changes that result in fluidization or stiffening of the melt can be induced by crystal growth from the melt or variation in oxygen fugacity. However, the rheological effects of water and crystal content alone cannot explain the correlation between composition and eruptive style. We conclude that the composition of calcalkaline rhyolites is decisive in determining the mobilization and eruption dynamics of Earth's largest volcanic systems, resulting in a better understanding of how the melt structure controls volcanic processes.

Common Occurrence of Explosive Hydrogen Burning in Type II Supernovae

NASA Astrophysics Data System (ADS)

Liu, Nan; Stephan, Thomas; Boehnke, Patrick; Nittler, Larry R.; Meyer, Bradley S.; O’D. Alexander, Conel M.; Davis, Andrew M.; Trappitsch, Reto; Pellin, Michael J.

2018-03-01

We report Mo isotopic data for 16 15N-rich presolar SiC grains of type AB (14N/15N < solar, AB1) and their correlated Sr and Ba isotope ratios when available. Of the 16 AB1 grains, 8 show s-process Mo isotopic compositions, together with s-process Ba and/or Sr isotopic compositions. We found that a higher percentage of AB1 grains show anomalous isotopic compositions than that of AB2 grains (14N/15N > solar), thus providing further support to the division of the two AB subgroups recently proposed by Liu et al., who showed that AB1 grains most likely originated from Type II supernovae (SNe) with explosive H burning. Comparison of the Sr, Mo, and Ba isotopic compositions of the AB1 grains with SN model predictions indicates that the s-process isotopic compositions of AB1 grains resulted from neutron-capture processes occurring during the progenitor massive stars’ pre-SN evolution rather than from an explosive neutron-capture process. In addition, the observations of (1) explosive H burning occurring in the C-rich regions of the progenitor SNe of X grains as suggested by the isotopic compositions of X grains, and (2) explosive H burning occurring both at the bottom of the He/C zone and at the top of the He/N zone as suggested by model simulations, imply that explosive H burning is a common phenomenon in outer SN zones.

Common Occurrence of Explosive Hydrogen Burning in Type II Supernovae

DOE PAGES

Liu, Nan; Stephan, Thomas; Boehnke, Patrick; ...

2018-03-16

In this paper, we report Mo isotopic data for 16 15N-rich presolar SiC grains of type AB ( 14N/ 15N < solar, AB1) and their correlated Sr and Ba isotope ratios when available. Of the 16 AB1 grains, 8 show s-process Mo isotopic compositions, together with s-process Ba and/or Sr isotopic compositions. We found that a higher percentage of AB1 grains show anomalous isotopic compositions than that of AB2 grains ( 14N/ 15N > solar), thus providing further support to the division of the two AB subgroups recently proposed by Liu et al., who showed that AB1 grains most likelymore » originated from Type II supernovae (SNe) with explosive H burning. Comparison of the Sr, Mo, and Ba isotopic compositions of the AB1 grains with SN model predictions indicates that the s-process isotopic compositions of AB1 grains resulted from neutron-capture processes occurring during the progenitor massive stars' pre-SN evolution rather than from an explosive neutron-capture process. Finally, in addition, the observations of (1) explosive H burning occurring in the C-rich regions of the progenitor SNe of X grains as suggested by the isotopic compositions of X grains, and (2) explosive H burning occurring both at the bottom of the He/C zone and at the top of the He/N zone as suggested by model simulations, imply that explosive H burning is a common phenomenon in outer SN zones.« less

Common Occurrence of Explosive Hydrogen Burning in Type II Supernovae

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

Liu, Nan; Stephan, Thomas; Boehnke, Patrick

In this paper, we report Mo isotopic data for 16 15N-rich presolar SiC grains of type AB ( 14N/ 15N < solar, AB1) and their correlated Sr and Ba isotope ratios when available. Of the 16 AB1 grains, 8 show s-process Mo isotopic compositions, together with s-process Ba and/or Sr isotopic compositions. We found that a higher percentage of AB1 grains show anomalous isotopic compositions than that of AB2 grains ( 14N/ 15N > solar), thus providing further support to the division of the two AB subgroups recently proposed by Liu et al., who showed that AB1 grains most likelymore » originated from Type II supernovae (SNe) with explosive H burning. Comparison of the Sr, Mo, and Ba isotopic compositions of the AB1 grains with SN model predictions indicates that the s-process isotopic compositions of AB1 grains resulted from neutron-capture processes occurring during the progenitor massive stars' pre-SN evolution rather than from an explosive neutron-capture process. Finally, in addition, the observations of (1) explosive H burning occurring in the C-rich regions of the progenitor SNe of X grains as suggested by the isotopic compositions of X grains, and (2) explosive H burning occurring both at the bottom of the He/C zone and at the top of the He/N zone as suggested by model simulations, imply that explosive H burning is a common phenomenon in outer SN zones.« less

Explosive bonding of metal-matrix composites

NASA Technical Reports Server (NTRS)

Reece, O. Y.

1969-01-01

Explosive bonding process produces sheet composites of aluminum alloy reinforced by high-strength stainless steel wires. The bonds are excellent metallurgically, no external heat is required, various metals can be bonded, and the process is inexpensive.

The Gaseous Explosive Reaction : A Study of the Kinetics of Composite Fuels

NASA Technical Reports Server (NTRS)

Stevens, F W

1929-01-01

This report deals with the results of a series of studies of the kinetics of gaseous explosive reactions where the fuel under observation, instead of being a simple gas, is a known mixture of simple gases. In the practical application of the gaseous explosive reaction as a source of power in the gas engine, the fuels employed are composite, with characteristics that are apt to be due to the characteristics of their components and hence may be somewhat complex. The simplest problem that could be proposed in an investigation either of the thermodynamics or kinetics of the gaseous explosive reaction of a composite fuel would seem to be a separate study of the reaction characteristics of each component of the fuel and then a study of the reaction characteristics of the various known mixtures of those components forming composite fuels more and more complex. (author)

High pressure-resistant nonincendive emulsion explosive

DOEpatents

Ruhe, Thomas C.; Rao, Pilaka P.

1994-01-01

An improved emulsion explosive composition including hollow microspheres/bulking agents having high density and high strength. The hollow microspheres/bulking agents have true particle densities of about 0.2 grams per cubic centimeter or greater and include glass, siliceous, ceramic and synthetic resin microspheres, expanded minerals, and mixtures thereof. The preferred weight percentage of hollow microspheres/bulking agents in the composition ranges from 3.0 to 10.0 A chlorinated paraffin oil, also present in the improved emulsion explosive composition, imparts a higher film strength to the oil phase in the emulsion. The emulsion is rendered nonincendive by the production of sodium chloride in situ via the decomposition of sodium nitrate, a chlorinated paraffin oil, and sodium perchlorate. The air-gap sensitivity is improved by the in situ formation of monomethylamine perchlorate from dissolved monomethylamine nitrate and sodium perchlorate. The emulsion explosive composition can withstand static pressures to 139 bars and dynamic pressure loads on the order of 567 bars.

Comparative studies on structures, mechanical properties, sensitivity, stabilities and detonation performance of CL-20/TNT cocrystal and composite explosives by molecular dynamics simulation.

PubMed

Hang, Gui-Yun; Yu, Wen-Li; Wang, Tao; Wang, Jin-Tao; Li, Zhen

2017-09-19

To investigate and compare the differences of structures and properties of CL-20/TNT cocrystal and composite explosives, the CL-20/TNT cocrystal and composite models were established. Molecular dynamics simulations were performed to investigate the structures, mechanical properties, sensitivity, stabilities and detonation performance of cocrystal and composite models with COMPASS force field in NPT ensemble. The lattice parameters, mechanical properties, binding energies, interaction energy of trigger bond, cohesive energy density and detonation parameters were determined and compared. The results show that, compared with pure CL-20, the rigidity and stiffness of cocrystal and composite models decreased, while plastic properties and ductility increased, so mechanical properties can be effectively improved by adding TNT into CL-20 and the cocrystal model has better mechanical properties. The interaction energy of the trigger bond and the cohesive energy density is in the order of CL-20/TNT cocrystal > CL-20/TNT composite > pure CL-20, i.e., cocrystal model is less sensitive than CL-20 and the composite model, and has the best safety parameters. Binding energies show that the cocrystal model has higher intermolecular interaction energy values than the composite model, thus illustrating the better stability of the cocrystal model. Detonation parameters vary as CL-20 > cocrystal > composite, namely, the energy density and power of cocrystal and composite model are weakened; however, the CL-20/TNT cocrystal explosive still has desirable energy density and detonation performance. This results presented in this paper help offer some helpful guidance to better understand the mechanism of CL-20/TNT cocrystal explosives and provide some theoretical assistance for cocrystal explosive design.

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.

Predicting High Explosive Detonation Velocities from Their Composition and Structure

DTIC Science & Technology

1978-09-01

for a gamut of ideal explosives. The explosives ranged from nitroaromatics, cyclic and linear nitramines, nitrate esters and nitro-nitrato...structure is postulated for a gamut of explosives. Since detonation velocity, DQ, is density dependent, the linear regression plot. Figure 1, of the

Special Features of Structure Formation in an Explosion-Welded Magnesium-Aluminum Composite Under Deformation and Subsequent Heat Treatment

NASA Astrophysics Data System (ADS)

Gurevich, L. M.; Arisova, V. N.; Trykov, Yu. P.; Ponomareva, I. A.; Trudov, A. F.

2016-07-01

The effect of bending deformation and subsequent heat treatment on the variation of microhardness and structure of explosion-welded magnesium-aluminum layered composite material MA2-1 - AD1 is studied.

Donor free radical explosive composition

DOEpatents

Walker, Franklin E. [15 Way Points Rd., Danville, CA 94526; Wasley, Richard J. [4290 Colgate Way, Livermore, CA 94550

1980-04-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a donor additive comprising an organic compound or mixture of organic compounds capable of releasing low molecular weight free radicals or ions under mechanical or electrical shock conditions and which is not an explosive, or an inorganic compound or mixture of inorganic compounds capable of releasing low molecular weight free radicals or ions under mechanical or electrical shock conditions and selected from ammonium or alkali metal persulfates.

The functional significance of hamstrings composition: is it really a "fast" muscle group?

PubMed

Evangelidis, Pavlos E; Massey, Garry J; Ferguson, Richard A; Wheeler, Patrick C; Pain, Matthew T G; Folland, Jonathan P

2017-11-01

Hamstrings muscle fiber composition may be predominantly fast-twitch and could explain the high incidence of hamstrings strain injuries. However, hamstrings muscle composition in vivo, and its influence on knee flexor muscle function, remains unknown. We investigated biceps femoris long head (BFlh) myosin heavy chain (MHC) composition from biopsy samples, and the association of hamstrings composition and hamstrings muscle volume (using MRI) with knee flexor maximal and explosive strength. Thirty-one young men performed maximal (concentric, eccentric, isometric) and explosive (isometric) contractions. BFlh exhibited a balanced MHC distribution [mean ± SD (min-max); 47.1 ± 9.1% (32.6-71.0%) MHC-I, 35.5 ± 8.5% (21.5-60.0%) MHC-IIA, 17.4 ± 9.1% (0.0-30.9%) MHC-IIX]. Muscle volume was correlated with knee flexor maximal strength at all velocities and contraction modes (r = 0.62-0.76, P < 0.01), but only associated with late phase explosive strength (time to 90 Nm; r = -0.53, P < 0.05). In contrast, BFlh muscle composition was not related to any maximal or explosive strength measure. BFlh MHC composition was not found to be "fast", and therefore composition does not appear to explain the high incidence of hamstrings strain injury. Hamstrings muscle volume explained 38-58% of the inter-individual differences in knee flexor maximum strength at a range of velocities and contraction modes, while BFlh muscle composition was not associated with maximal or explosive strength. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test

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

Vandersall, K S; Switzer, L L; Garcia, F

2005-09-26

Steven Impact Tests were performed at low velocity on the explosives TNT, Comp B, and C-4 in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, or C-4 explosive samples impacted up to velocities in the range of 190-200 m/s. This workmore » will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives.« less

Structural transformations and properties of titanium-aluminum composite during heat treatment

NASA Astrophysics Data System (ADS)

Pervukhin, L. B.; Kryukov, D. B.; Krivenkov, A. O.; Chugunov, S. N.

2017-08-01

The link between the parameters of heat treatment of a layered titanium-aluminum composite material obtained by explosive welding with the formation of intermetallic compounds in it has been analyzed. The results of measurements of the microhardness of the composite and the thickness of the interlayer of the intermetallic phase obtained using different regimes of heat treatment have been discussed. Special attention has been paid to estimating the composition of the intermetallic phase in the composite prepared by explosive welding.

Controls on Explosive Eruptions along the Pacific-Antarctic Ridge

NASA Astrophysics Data System (ADS)

Lewis, M.; Asimow, P. D.; Lund, D. C.

2016-12-01

Sediment core OC170-26-159 was retrieved at 38.967°S, 111.35°W, a location that was 8-9km away from the Pacific-Antarctic Ridge (PAR) axis at the time of Glacial Termination II (T-II), 130ka, a period characterized by enhanced flux of hydrothermal metals to the near-ridge sediments on the East Pacific Rise (Lund et. al. 2016). An interval of enhanced Ti content in OC170-26-159 during T-II is rich in basaltic glass shards that we interpret to be the products of explosive submarine volcanic eruptions. Explosive eruptions of this scale are rare at mid-ocean ridges, so we studied the glass to evaluate whether sea level driven modulation in magmatic flux might be related to the frequency of such events though emplacement of distinct compositions or volatile contents. We report major element and volatile content data for the basaltic glasses and compare the results to literature data (PetDB) from on-axis sampling of the nearest ridge segment, to assess whether the glass was derived from the ridge axis and if it is unusual compared to the axial samples. Major element compositional data show that the glasses are a nearly homogenous population (MgO 5.8 to 6.5%). The heterogeneity is similar to that in single flows in Iceland (Maclennan et. al. 2003) and Hawaii (Garcia et. al. 2000), but the shards are dispersed across a gradient in δ18O, suggesting a closely spaced series of similar eruptions. The glasses are more evolved than any effusively erupted basalts on the PAR, yet are consistent with the same liquid line of descent, linking the explosive products to the axial magmatic system. The MELTS thermodynamic model allows us to calculate the changes in multiple variables along the liquid line of descent between the axial and explosive liquid compositions. Comparison of H2O and CO2 contents to those from axial flows will constrain whether variations in these components are related to eruption styles. These results will constrain the connection between sea level driven variations in magma supply rate, hydrothermal activity, thermal state of the axial magma chamber, volatile exsolution, and the potential for explosive submarine eruptions.

Features of the incorporation of single and double based powders within emulsion explosives

NASA Astrophysics Data System (ADS)

Ribeiro, J. B.; Mendes, R.; Tavares, B.; Louro, C.

2014-05-01

In this work, features of the thermal and detonation behaviour of compositions resulting from the mixture of single and double based powders within ammonium nitrate based emulsion explosives are shown. Those features are portrayed through results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential thermal analysis [DTA] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the "gap-test". DTA/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical species and so of the compatibility of the components of the compositions. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with powder than for the one with sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have been shown to be higher for the powdered compositions than for the sole emulsion explosive. Shock sensitivity assessments have ended-up with a slightly bigger sensitivity for the compositions with double based powder when compared to the single based compositions or to the sole emulsion.

Features of the Valorization of Single and Double Based Powders for Codetonation in Emulsion Explosives

NASA Astrophysics Data System (ADS)

Ribeiro, Jose; Mendes, Ricardo; Tavares, Bruno; Louro, Cristina

2013-06-01

In this work, features of the thermal and detonation behavior of compositions resulting from the mixture of single and double based gun powder within ammonium nitrate (AN) based emulsion explosives are shown. That includes results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential scanning calorimetry [DSC] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the ``gap-test''. DSC/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical specimens and so of the capability of the composition components. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with gun powder than for the sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have shown to be higher for the powdered compositions than for the pure emulsion explosive. Shock sensitivity assessment have ended-up with a slightly bigger sensitivity for the compositions with double based gun powder when compared to the single based compositions or to the pure emulsion.

Mishap risk control for advanced aerospace/composite materials

NASA Technical Reports Server (NTRS)

Olson, John M.

1994-01-01

Although advanced aerospace materials and advanced composites provide outstanding performance, they also present several unique post-mishap environmental, safety, and health concerns. The purpose of this paper is to provide information on some of the unique hazards and concerns associated with these materials when damaged by fire, explosion, or high-energy impact. Additionally, recommended procedures and precautions are addressed as they pertain to all phases of a composite aircraft mishap response, including fire-fighting, investigation, recovery, clean-up, and guidelines are general in nature and not application-specific. The goal of this project is to provide factual and realistic information which can be used to develop consistent and effective procedures and policies to minimize the potential environmental, safety, and health impacts of a composite aircraft mishap response effort.

Welding of titanium and stainless steel using the composite insert

NASA Astrophysics Data System (ADS)

Cherepanov, A. N.; Mali, V. I.; Orishich, A. M.; Malikov, A. G.; Drozdov, V. O.; Malyutina, Y. N.

2016-11-01

The paper concerns the possibility of obtaining a lasting permanent joint of dissimilar metals: technically pure titanium and stainless steel using laser welding and an intermediate composite insert. The insert was a four-layer composition of plates of steel, copper, niobium, and titanium welded by explosion. The material layers used in the insert prevented the molten steel and titanium from mixing, which excluded the formation of brittle intermetallic compounds, such as FeTi and Fe2Ti. The optimization of explosion welding parameters provided a high quality of the four-layer composition and the absence of defects in the area of the joint of insert plates. The results of strength tests showed that values of the ultimate strength and yield of the permanent joint with the composite insert welded by explosion are comparable to the strength characteristics of titanium.

Thermally stable, plastic-bonded explosives

DOEpatents

Benziger, Theodore M.

1979-01-01

By use of an appropriate thermoplastic rubber as the binder, the thermal stability and thermal stress characteristics of plastic-bonded explosives may be greatly improved. In particular, an HMX-based explosive composition using an oil-extended styrene-ethylenebutylene-styrene block copolymer as the binder exhibits high explosive energy and thermal stability and good handling safety and physical properties.

Dissolution and sorption of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) residues from detonated mineral surfaces.

PubMed

Jaramillo, Ashley M; Douglas, Thomas A; Walsh, Marianne E; Trainor, Thomas P

2011-08-01

Composition B (Comp B) is a commonly used military formulation composed of the toxic explosive compounds 2,4,6-trinitrotoluene (TNT), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Numerous studies of the temporal fate of explosive compounds in soils, surface water and laboratory batch reactors have been conducted. However, most of these investigations relied on the application of explosive compounds to the media via aqueous addition and thus these studies do not provide information on the real world loading of explosive residues during detonation events. To address this we investigated the dissolution and sorption of TNT and RDX from Comp B residues loaded to pure mineral phases through controlled detonation. Mineral phases included nontronite, vermiculite, biotite and Ottawa sand (quartz with minor calcite). High Performance Liquid Chromatography and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy were used to investigate the dissolution and sorption of TNT and RDX residues loaded onto the mineral surfaces. Detonation resulted in heterogeneous loading of TNT and RDX onto the mineral surfaces. Explosive compound residues dissolved rapidly (within 9 h) in all samples but maximum concentrations for TNT and RDX were not consistent over time due to precipitation from solution, sorption onto mineral surfaces, and/or chemical reactions between explosive compounds and mineral surfaces. We provide a conceptual model of the physical and chemical processes governing the fate of explosive compound residues in soil minerals controlled by sorption-desorption processes. Published by Elsevier Ltd.

Thermoplastic Explosive Compositions on the Base of Hexanitrohexaazaisowurtzitane

NASA Astrophysics Data System (ADS)

Ilyin, V. P.; Smirnov, S. P.; Kolganov, E. V.; Pechenev, Yu. G.

2006-08-01

Hexanitrohexaazaisowurtzitane is an azostructural compound known as CL-20. We performed a series of experiments with CL-20 synthesized in Russia to evaluate the possibility to use it in pressed high explosive compositions. We used it in thermoplastic compositions both with an inert binder and energetic binder. The compositions were conventionally named CL-20И and CL-20A. It was determined that the thermoplastic compositions had the most high detonation parameters and a level of sensitivity to mechanical effects acceptable to allow their processing. Their detonation characteristics were compared with that of some known foreign compositions based on CL-20.

The volcanic explosivity index /VEI/ - An estimate of explosive magnitude for historical volcanism

NASA Technical Reports Server (NTRS)

Newhall, C. G.; Self, S.

1982-01-01

A composite estimate of the magnitude of past explosive eruptions, referred to as the Volcanic Explosivity Index (VEI), is proposed as a semiquantitative compromise between poor data and the need in various disciplines to evaluate the record of past volcanism. The VEI is assigned to more than 8000 historic and prehistoric eruptions. It is shown that the VEI can help detect incompleteness and reporting biases and can help in selecting subsets of the historical record suitable for each study. The VEI is a composite estimate of Walkers (1980) magnitude and/or intensity and/or destructiveness and/or (less frequently) dispersive power, violence, and energy release rate, depending on the data that are available.

Non-Newtonian behavior observed via dynamic rheology for various particle types in energetic materials and simulant composites

NASA Astrophysics Data System (ADS)

Choi, Jong Han; Lee, Sangmook; Lee, Jae Wook

2017-02-01

The rheological properties of polymer composites highly filled with different filler materials were examined using a stress-controlled rheometer with a parallel-plate configuration, for particle characterization of the filler materials in plastic (polymer) bonded explosive (PBX). Ethylene vinyl acetate (EVA) with dioctyl adipate (DOA) was used as the matrix phase, which was shown to exhibit Newtonian-like behavior. The dispersed phase consisted of one of two energetic materials, i.e., explosive cyclotrimethylene trinitramine (RDX) or cyclotetramethylene tetranitramine (HMX), or a simulant (Dechlorane) in a bimodal size distribution. Before the test, preshearing was conducted to identify the initial condition of each sample. All examined filled polymer specimens exhibited yield stress and shear-thinning behavior over the investigated frequency range. The complex viscosity dependence on the dynamic oscillation frequency was also fitted using an appropriate rheological model, suggesting the model parameters. Furthermore, the temperature dependency of the different filler particle types was determined for different filler volume fractions. These comparative studies revealed the influence of the particle characteristics on the rheological properties of the filled polymer.

THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST

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

Vandersall, K S; Switzer, L L; Garcia, F

2006-06-20

Steven Impact Tests were performed at low velocity on the explosives TNT (trinitrotolulene), Composition B (63% RDX, 36% TNT, and 1% wax by weight), C-4 (91% RDX, 5.3% Di (2-ethylhexyl) sebacate, 2.1% Polyisobutylene, and 1.6% motor oil by weight) and ANFO (94% ammonium Nitrate with 6% Fuel Oil) in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the levelmore » of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, C-4 or ANFO explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives. These results will also be compared to that of the Susan Test and reaction thresholds observed in the common small-scale safety tests such as the drop hammer and friction tests in hopes of drawing a correlation.« less

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.

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

Martz, Joseph Christopher; Spearing, Dane Robert; Labouriau, Andrea

Microclad is a composite material consisting of a thin copper coating applied on a single side over a Kapton substrate. Kapton is the commercial designator for polyimide supplied by DuPont. Microclad is a key material in detonator manufacture and function. Detonators which utilize Microclad function when a large current applied through a thin bridge etched into the copper produces a plasma, accelerating a Kapton flyer into an explosive (PETN) pellet. The geometry and properties of the Microclad are a critical element of this process.

Explosion and combustion properties of alkylsilanes I : temperature-composition limits of explosion for methyl-,dimethyl-,trimethyl-,tetramethyl-,and vinylsilane at atmospheric pressure

NASA Technical Reports Server (NTRS)

Schalla, Rose L; Mcdonald, Glen E

1954-01-01

The explosion limits of five alkylsilanes were determined as a function of temperature and composition at a pressure of 1 atmosphere. Over a fuel concentration range of 2 to 10 percent, the lowest temperatures (zero C) below which explosion did not occur for the five fuels studied were: tetramethylsilane (CHsub3)sub4Si, 450 degrees; trimethlysilane (CHsub3)sub3SiH, 310 degrees;dimethylsilane (CHsub3)sub2SiHsub2, 220 degrees; methylsilane CHsub3SiHsub3, 130 degrees; and vinylsilane Hsub2C=CH-SiHsub3, 90 degrees. Explosion limits for hydrocarbons analogous to these silanes fall in a temperature range of 500 degrees to 600 degrees C. Since the explosion temperatures of the alkylsilanes are lower than those of the hydrocarbons and since they decrease as hydrogen atoms are substituted for methyl groups, it was concluded that the Si-H bond is more readily susceptible to oxidation than the C-H bond.

Microstructure and Properties of 5083 Al/1060 Al/AZ31 Composite Plate Fabricated by Explosive Welding

NASA Astrophysics Data System (ADS)

Yang, Suyuan; Bao, Jiawei

2018-03-01

A 5083 Al/1060 Al/AZ31 composite plate was fabricated by explosive welding. The microstructure and properties of the composite plate were investigated after explosive welding. The results showed that all bonding interfaces were wavy interfaces. With an increasing distance from the detonation point, the wavelength and the amplitude also increased. The EDS results indicated that a 5-μm diffusion layer was observed at the 1060 Al/AZ31 layer, including the Mg2Al3 phase. Adiabatic shear bands and twin structures were observed in AZ31. The shear bond strength of the 5083 Al/1060 Al interface was 60 MPa, and the shear bond strength of the 1060 Al/AZ31 interface was 84 MPa.

Progress on determining the vapor signature of a buried land mine

NASA Astrophysics Data System (ADS)

George, Vivian; Jenkins, Thomas F.; Leggett, Daniel C.; Cragin, James H.; Phelan, James M.; Oxley, Jimmie C.; Pennington, Judy

1999-08-01

The goal of the DARPA 'Dog's Nose' program is to develop a sensor capable of detecting explosives contained in all buried landmines. In support of the DARPA program, the purpose of the Explosives Fate and Transport experiments is to define in detail the accessible trace chemical signature produced by the explosives contained in buried landmines. We intend to determine the partitioning, composition, and quantity of explosive related chemicals which emanate from different kinds of landmines buried in multiple soil types and exposed to various climatic events. We are also developing a computer model that will enable us to predict the composition and quantity of ERC under a much wider range of environmental conditions than we are able to test experimentally.

Predicting the Plate Dent Test Output in Order to Assess the Performance of Condensed High Explosives

NASA Astrophysics Data System (ADS)

Frem, Dany

2017-01-01

In the present study, a relationship is proposed that is capable of predicting the output of the plate dent test. It is shown that the initial density ?; condensed phase heat of formation ?; the number of carbon (C), nitrogen (N), oxygen (O); and the composition molecular weight (MW) are the most important parameters needed in order to accurately predict the absolute dent depth ? produced on 1018 cold-rolled steel by a detonating organic explosive. The estimated ? values can be used to predict the detonation pressure (P) of high explosives; furthermore, we show that a correlation exists between ? and the Gurney velocity ? parameter. The new correlation is used to accurately estimate ? for several C-H-N-O explosive compositions.

Hydrothermal pretreatment of wood by mild steam explosion and hot water extraction.

PubMed

Wojtasz-Mucha, Joanna; Hasani, Merima; Theliander, Hans

2017-10-01

The aim of this work was to compare the two most common hydrothermal pre-treatments for wood - mild steam explosion and hot water extraction - both with the prospect of enabling extraction of hemicelluloses and facilitating further processing. Although both involve autohydrolysis of the lignocellulosic tissue, they are performed under different conditions: the most prominent difference is the rapid, disintegrating, discharge employed in the steam explosion opening up the structure. In this comparative study, the emphasis was placed on local composition of the pre-treated wood chips (of industrially relevant size). The results show that short hot water extraction treatments lead to significant variations in the local composition within the wood chips, while steam explosion accomplishes a comparably more even removal of hemicelluloses due to the advective mass transport during the explosion step. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimisation of recovery protocols for double-base smokeless powder residues analysed by total vaporisation (TV) SPME/GC-MS.

PubMed

Sauzier, Georgina; Bors, Dana; Ash, Jordan; Goodpaster, John V; Lewis, Simon W

2016-09-01

The investigation of explosive events requires appropriate evidential protocols to recover and preserve residues from the scene. In this study, a central composite design was used to determine statistically validated optimum recovery parameters for double-base smokeless powder residues on steel, analysed using total vaporisation (TV) SPME/GC-MS. It was found that maximum recovery was obtained using isopropanol-wetted swabs stored under refrigerated conditions, then extracted for 15min into acetone on the same day as sample collection. These parameters were applied to the recovery of post-blast residues deposited on steel witness surfaces following a PVC pipe bomb detonation, resulting in detection of all target components across the majority of samples. Higher overall recoveries were obtained from plates facing the sides of the device, consistent with the point of first failure occurring in the pipe body as observed in previous studies. The methodology employed here may be readily applied to a variety of other explosive compounds, and thus assist in establishing 'best practice' procedures for explosive investigations. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of particle size and particle size distribution on physical characteristics, morphology and crystal structure of explosively compacted high-T(sub c) superconductors

NASA Technical Reports Server (NTRS)

Kotsis, I.; Enisz, M.; Oravetz, D.; Szalay, A.

1995-01-01

A superconductor, of composition Y(Ba,K,Na)2Cu3O(x)/F(y) and a composite of composition Y(Ba,K,Na)2Cu3O(x)/F(y) + Ag, with changing K, Na and F content but a constant silver content (Ag = 10 mass%) was prepared using a single heat treatment. the resulting material was ground in a corundum lined mill, separated to particle size fractions of 0-40 micron, 0-63 micron and 63-900 micron and explosively compacted, using an explosive pressure of 10(exp 4) MPa and a subsequent heat treatment. Best results were obtained with the 63-900 micron fraction of composition Y(Ba(1.95) K(0.01)Cu3O(x)F(0),(05)/Ag: porosity less than 0.01 cu cm/g and current density 2800 A/sq cm at 77K.

Discrimination of smokeless powders by headspace SPME-GC-MS and SPME-GC-ECD, and the potential implications upon training canine detection of explosives

NASA Astrophysics Data System (ADS)

Harper, Ross J.; Almirall, Jose R.; Furton, Kenneth G.

2005-05-01

This presentation will provide an odour analysis of a variety of smokeless powders & communicate the rapid SPME-GC-ECD method utilized. This paper will also discuss the implications of the headspace analysis of Smokeless Powders upon the choice of training aids for Explosives Detection Canines. Canine detection of explosives relies upon the dogs" ability to equate finding a given explosive odour with a reward, usually in the form of praise or play. The selection of explosives upon which the dogs are trained thus determines which explosives the canines can and potentially cannot find. Commonly, the training is focussed towards high explosives such as TNT and Composition 4, and the low explosives such as Black and Smokeless Powders are added often only for completeness. Powder explosives constitute a major component of explosive incidents throughout the US, and canines trained to detect explosives must be trained across the entire range of powder products. Given the variability in the manufacture and product make-up many smokeless powders do not share common odour chemicals, giving rise to concerns over the extensiveness of canine training. Headspace analysis of a selection of Smokeless Powders by Solid Phase Microextraction Gas Chromatography using Mass Spectrometry (SPME-GC-MS) and Electron Capture Detectors (SPME-GC-ECD) has highlighted significant differences in the chemical composition of the odour available from different brands. This suggests that greater attention should be paid towards the choice of Powder Explosives when assigning canine training aids.

Non-detonable and non-explosive explosive simulators

DOEpatents

Simpson, Randall L.; Pruneda, Cesar O.

1997-01-01

A simulator which is chemically equivalent to an explosive, but is not detonable or explodable. The simulator is a combination of an explosive material with an inert material, either in a matrix or as a coating, where the explosive has a high surface ratio but small volume ratio. The simulator has particular use in the training of explosives detecting dogs, calibrating analytical instruments which are sensitive to either vapor or elemental composition, or other applications where the hazards associated with explosives is undesirable but where chemical and/or elemental equivalence is required. The explosive simulants may be fabricated by different techniques. A first method involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and a second method involves coating inert substrates with thin layers of explosive.

27 CFR 555.201 - General.

Code of Federal Regulations, 2011 CFR

2011-04-01

... fireworks, pyrotechnic compositions, and explosive materials used in assembling fireworks and articles pyrotechnic. (e) The provisions of § 555.202(a) classifying flash powder and bulk salutes as high explosives...

27 CFR 555.201 - General.

Code of Federal Regulations, 2010 CFR

2010-04-01

... fireworks, pyrotechnic compositions, and explosive materials used in assembling fireworks and articles pyrotechnic. (e) The provisions of § 555.202(a) classifying flash powder and bulk salutes as high explosives...

Concepts of Ideal and Nonideal Explosives.

DTIC Science & Technology

1981-12-01

Akst and J. Hershkowitz, "Explosive Performance Modification by Cosolidifaction of Ammonium Nitrate with Fuels ," Technical Report 4987, Picatinny...explosives Equations of state Diameter effect Ammonium nitrate 20. ASSrRACr (ca’mes r w re t N netwezy ad identity by block number) The purpose of...this report is to stimulate discussion on the nonideality of ammonium nitrate and its composite explosives. The concept of ideal and non- ideal

Discovery of a Powerful, Transient, Explosive Thermal Event at Marduk Fluctus, Io, in Galileo NIMS Data

NASA Astrophysics Data System (ADS)

Davies, A. G.; Davies, R. L.; Veeder, G. J.; de Kleer, K.; de Pater, I.; Matson, D. L.; Johnson, T. V.; Wilson, L.

2018-04-01

Analysis of Galileo Near-Infrared Mapping Spectrometer observations of Marduk Fluctus, a volcano on the Jovian moon Io, reveals a style of volcanic activity not previously seen there—a powerful thermal event lasting only a few minutes in 1996. The thermal emission rapidly fades, suggesting extremely rapid cooling of small clasts. The duration and evolution of the explosive eruption are akin to what might be expected from a strombolian or vulcanian explosion. The presence of such events provides an additional volcanic process that can be imaged by future missions with the intent of determining lava composition from eruption temperature, an important constraint on the internal composition of Io. These data promise to be of particular use in understanding the mechanics of explosive volcanic processes on Io.

Novel high explosive compositions

DOEpatents

Perry, D.D.; Fein, M.M.; Schoenfelder, C.W.

1968-04-16

This is a technique of preparing explosive compositions by the in-situ reaction of polynitroaliphatic compounds with one or more carboranes or carborane derivatives. One or more polynitroaliphatic reactants are combined with one or more carborane reactants in a suitable container and mixed to a homogeneous reaction mixture using a stream of inert gas or conventional mixing means. Ordinarily the container is a fissure, crack, or crevice in which the explosive is to be implanted. The ratio of reactants will determine not only the stoichiometry of the system, but will effect the quality and quantity of combustion products, the explosive force obtained as well as the impact sensitivity. The test values can shift with even relatively slight changes or modifications in the reaction conditions. Eighteen illustrative examples accompany the disclosure. (46 claims)

49 CFR 173.56 - New explosives-definition and procedures for classification and approval.

Code of Federal Regulations, 2012 CFR

2012-10-01

... agency the ranges of composition of ingredients and compounds, showing the intended manufacturing... was produced to an explosives testing range if— (1) It is not a primary (a 1.1A initiating) explosive...) Ammunition with inert projectile or blank ammunition; and (4) Ammunition not exceeding 50 caliber for rifle...

49 CFR 173.56 - New explosives-definition and procedures for classification and approval.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the ranges of composition of ingredients and compounds, showing the intended manufacturing tolerances... was produced to an explosives testing range if— (1) It is not a primary (a 1.1A initiating) explosive...; (3) Ammunition with inert projectile or blank ammunition; and (4) Ammunition not exceeding 50 caliber...

49 CFR 173.56 - New explosives-definition and procedures for classification and approval.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the ranges of composition of ingredients and compounds, showing the intended manufacturing tolerances... was produced to an explosives testing range if— (1) It is not a primary (a 1.1A initiating) explosive...; (3) Ammunition with inert projectile or blank ammunition; and (4) Ammunition not exceeding 50 caliber...

49 CFR 173.56 - New explosives-definition and procedures for classification and approval.

Code of Federal Regulations, 2011 CFR

2011-10-01

... agency the ranges of composition of ingredients and compounds, showing the intended manufacturing... was produced to an explosives testing range if— (1) It is not a primary (a 1.1A initiating) explosive...) Ammunition with inert projectile or blank ammunition; and (4) Ammunition not exceeding 50 caliber for rifle...

46 CFR 35.30-25 - Explosives-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Explosives-TB/ALL. 35.30-25 Section 35.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS General Safety Rules § 35.30-25 Explosives—TB/ALL. Fulminates or other detonating compounds in bulk in dry condition; explosive compositions...

46 CFR 35.30-25 - Explosives-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Explosives-TB/ALL. 35.30-25 Section 35.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS General Safety Rules § 35.30-25 Explosives—TB/ALL. Fulminates or other detonating compounds in bulk in dry condition; explosive compositions...

46 CFR 35.30-25 - Explosives-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Explosives-TB/ALL. 35.30-25 Section 35.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS General Safety Rules § 35.30-25 Explosives—TB/ALL. Fulminates or other detonating compounds in bulk in dry condition; explosive compositions...

46 CFR 35.30-25 - Explosives-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Explosives-TB/ALL. 35.30-25 Section 35.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS General Safety Rules § 35.30-25 Explosives—TB/ALL. Fulminates or other detonating compounds in bulk in dry condition; explosive compositions...

46 CFR 35.30-25 - Explosives-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Explosives-TB/ALL. 35.30-25 Section 35.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS General Safety Rules § 35.30-25 Explosives—TB/ALL. Fulminates or other detonating compounds in bulk in dry condition; explosive compositions...

Non-detonable and non-explosive explosive simulators

DOEpatents

Simpson, R.L.; Pruneda, C.O.

1997-07-15

A simulator which is chemically equivalent to an explosive, but is not detonable or explodable is disclosed. The simulator is a combination of an explosive material with an inert material, either in a matrix or as a coating, where the explosive has a high surface ratio but small volume ratio. The simulator has particular use in the training of explosives detecting dogs, calibrating analytical instruments which are sensitive to either vapor or elemental composition, or other applications where the hazards associated with explosives is undesirable but where chemical and/or elemental equivalence is required. The explosive simulants may be fabricated by different techniques. A first method involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and a second method involves coating inert substrates with thin layers of explosive. 11 figs.

Thermal explosion violence of HMX-based explosives -- effect of composition, confinement and phase transition using the scaled thermal explosion experiment

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

Maienschein, J L; Wardell, J F; Reaugh, J E

We developed the Scaled Thermal Explosion Experiment (STEX) to provide a database of reaction violence from thermal explosion of explosives of interest. A cylinder of explosive, 1, 2 or 4 inches in diameter, is confined in a steel cylinder with heavy end caps, and heated under controlled conditions until it explodes. Reaction violence is quantified by micropower radar measurement of the cylinder wall velocity, and by strain gauge data at reaction onset. Here we describe the test concept and design, show that the conditions are well understood, and present initial data with HMX-based explosives. The HMX results show that anmore » explosive with high binder content yields less-violent reactions that an explosive with low binder content, and that the HMX phase at the time of explosion plays a key role in reaction violence.« less

Numerical Simulation of the Layer-Bylayer Destruction of Cylindrical Shells Under Explosive Loading

NASA Astrophysics Data System (ADS)

Abrosimov, N. A.; Novoseltseva, N. A.

2015-09-01

A technique of numerical analysis of the influence of reinforcement structure on the nature of the dynamic response and the process of layer-by-layer destruction of layered fiberglass cylindrical shells under an axisymmetric internal explosive loading is elaborated. The kinematic model of deformation of the laminate package is based on a nonclassical theory of shells. The geometric dependences are based on simple quadratic relations of the nonlinear theory of elasticity. The relationship between the stress and strain tensors are established by using Hooke's law for orthotropic bodies with account of degradation of stiffness characteristics of the multilayer composite due to the local destruction of some its elementary layers. An energetically consistent system of dynamic equations for composite cylindrical shells is obtained by minimizing the functional of total energy of the shell as a three-dimensional body. The numerical method for solving the formulated initial boundary-value problem is based on an explicit variational-difference scheme. Results confirming the reliability of the method used to analyze the influence of reinforcement structure on the character of destruction and the bearing capacity of pulse-loaded cylindrical shells are presented.

49 CFR 173.56 - New explosives-definition and procedures for classification and approval.

Code of Federal Regulations, 2010 CFR

2010-10-01

... tolerances in the composition of substances or design of articles which will be allowed in that material or... concurred in by: (i) U.S. Army Technical Center for Explosives Safety (SMCAC-EST), Naval Sea Systems Command... explosive (substance or article) and is packed, marked, labeled, described on shipping papers and is...

Insensitive explosive composition of halogenated copolymer and triaminotrinitrobenzene

DOEpatents

Benziger, Theodore M.

1976-01-01

A highly insensitive and heat resistant plastic-bonded explosive containing 90 wt % triaminotrinitrobenzene and 10 wt % of a fully saturated copolymer of chlorotrifluoroethylene and vinylidene fluoride is readily manufactured by the slurry process.

Andesites of the 2009 eruption of Redoubt Volcano, Alaska

USGS Publications Warehouse

Coombs, Michelle L.; Sisson, Thomas W.; Bleick, Heather A.; Henton, Sarah M.; Nye, Christopher J.; Payne, Allison; Cameron, Cheryl E.; Larsen, Jessica F.; Wallace, Kristi; Bull, Katharine F.

2013-01-01

Crystal-rich andesites that erupted from Redoubt Volcano in 2009 range from 57.5 to 62.5 wt.% SiO2 and have phenocryst and phenocryst-melt relations consistent with staging in the upper crust. Early explosive products are low-silica andesites (LSA, < 58 wt.% SiO2) that ascended from deeper crustal levels during or before the 6 months of precursory activity, but a broad subsequent succession to more evolved and cooler products, and predominantly effusive dome growth, are interpreted to result from progressive mobilization and mixing with differentiated magmas tapped from pre-2009 Redoubt intrusions at ~ 3–6 km depth. Initial explosions on March 23–28 ejected predominantly LSA with a uniform phenocryst assemblage of high-Al amphibole, ~ An70 plagioclase, ortho- and clinopyroxene, FeTi oxides (890 to 960 °C), and traces of magmatic sulfide. Melt in the dominant microlite-poor LSA was compositionally uniform dacite (67–68 wt.% SiO2) but ranged to rhyolite with greater microlite growth. Minor amounts of intermediate- to high-silica andesite (ISA, HSA; 59–62.5 wt.% SiO2) also erupted during the early explosions and most carried rhyolitic melt (72–74 wt.% SiO2). A lava dome grew following the initial tephra-producing events but was destroyed by an explosion on April 4. Ejecta from the April 4 explosion consists entirely of ISA and HSA, as does a subsequent lava dome that grew April 4–July 1; LSA was absent. Andesites from the April 4 event and from the final dome had pre-eruptive temperatures of 725–840 °C (FeTi oxides) and highly evolved matrix liquids (77–80 wt.% SiO2), including in rare microlite-free pyroclasts. ISA has mixed populations of phenocrysts suggesting it is a hybrid between HSA and LSA. The last lavas from the 2009 eruption, effused May 1–July 1, are distinctly depleted in P2O5, consistent with low temperatures and high degrees of crystallization including apatite.Plagioclase–melt hygrometry and comparison to phase equilibrium experiments are consistent with pre-eruptive storage of all three magma types at 100–160 MPa (4–6 km depth), if they were close to H2O-saturation, coincident with the locus of shallow syn-eruptive seismicity. Deeper storage would be indicated if the magmas were CO2-rich. Relatively coarse-grained clinopyroxene-rich reaction rims on many LSA amphibole phenocrysts may result from slow ascent to, or storage at, depths shallow enough for the onset of appreciable H2O exsolution, consistent with pre-eruptive staging in the uppermost crust. We interpret that the 2009 LSA ascended from depth during the 8 or more months prior to the first eruption, but that the magma stalled and accumulated in the upper crust where its phenocryst rim and melt compositions were established. Ascent of LSA through stagnant mushy intrusions residual from earlier Redoubt activity mobilized differentiated magma pockets and interstitial liquids represented by HSA, and as LSA–HSA hybrids represented by ISA, that fed the subsequently erupted lava domes.

Evolution of the Structure of Local Regions of Fused Metal in Explosion-Welded Nickel-Aluminum Composites Under Heat Treatment

NASA Astrophysics Data System (ADS)

Shmorgun, V. G.; Bogdanov, A. I.; Gurevich, L. M.

2016-03-01

The methods of electron, optical, and atomic force microscopy are used to study the structure, morphology and phase composition of local regions of fused metal in an explosion-welded nickel-aluminum composite. It is shown that the diffusion zone formed due to the heat treatment repeats the contour of the fuse in the first stage and then "absorbs" it upon duration of the hold thus leveling the phase composition. ANi2Al3 Aluminide layer forms on the side of nickel and a NiAl3 layer forms on the side of aluminum.

Development of Methodology and Technology for Identifying and Quantifying Emission Products from Open Burning and Open Detonation Thermal Treatment Methods. Field Test Series A, B, and C. Volume 1. Test Summary

DTIC Science & Technology

1992-01-01

3-37 Table 3.2 Nominal Composition of Explosive D ............................. 3-38 Table 3.3 Nominal Composition of PBXN -6...RDX used during Phase C was PBXN -6, a mixture of RDX and Viton An* (hereafter referred to as 3 RDX), The nominal composition of this explosive is...given in table 3.3. I I I I 3-38 3 I I Table 3.3 Nominal Composition of PBXN -6. II Carbon Content (%) Ingredient Weight (%)I __ .1• •,, ,,,,i, RDX 95.0

Investigation of the structure and properties of a composite insert applied at laser welding of steel with titanium

NASA Astrophysics Data System (ADS)

Pugacheva, N. B.; Cherepanov, A. N.; Orishich, A. M.; Malikov, A. G.; Drozdov, V. O.; Mali, V. I.; Senaeva, E. I.

2017-10-01

Production of welded bimetallic structures of titanium and steel using a laser beam is a very urgent and important task in the shipbuilding, airspace and power engineering. Laser welding using an intermediate insert is one of the ways to solve this problem. In this paper, we present the results of experimental studies of formation of the structure and properties of composite insert, obtained by explosion welding, after its application at laser welding steel with titanium. A study of a four-layer composite insert obtained by explosion welding showed that it has no brittle intermetallic phases and defects in the form of cracks and pores. The boundaries between the plates to be welded in the composite insert have a characteristic wavy structure with narrow zones of mutual diffusion penetration of elements of the adjacent metals. It is established that the strength of the composite insert is comparable with the maximum strength of Grade 4 alloy, and the destruction of the product during the tensile tests in most cases occurred along the weakest component of the composite insert, i.e. the copper layer, whose strength was significantly increased due to the hardening that took place in the explosion welding.

Fabrication of high temperature materials by exothermic synthesis and subsequent dynamic consolidation

DOEpatents

Rabin, Barry H.; Korth, Gary E.; Wright, Richard N.; Williamson, Richard L.

1992-01-01

An apparatus for synthesizing a composite material such as titanium carbide and alumina from exothermic reaction of a sample followed by explosive induced consolidation of the reacted sample. The apparatus includes a lower base for holding a powdered composite sample, an igniter and igniter powder for igniting the sample to initiate an exothermic reaction and a piston for dynamically compressing the sample utilizing an explosive reaction.

Effect of fuel composition and differential diffusion on flame stabilization in reacting syngas jets in turbulent cross-flow

DOE PAGES

Minamoto, Yuki; Kolla, Hemanth; Grout, Ray W.; ...

2015-07-24

Here, three-dimensional direct numerical simulation results of a transverse syngas fuel jet in turbulent cross-flow of air are analyzed to study the influence of varying volume fractions of CO relative to H 2 in the fuel composition on the near field flame stabilization. The mean flame stabilizes at a similar location for CO-lean and CO-rich cases despite the trend suggested by their laminar flame speed, which is higher for the CO-lean condition. To identify local mixtures having favorable mixture conditions for flame stabilization, explosive zones are defined using a chemical explosive mode timescale. The explosive zones related to flame stabilizationmore » are located in relatively low velocity regions. The explosive zones are characterized by excess hydrogen transported solely by differential diffusion, in the absence of intense turbulent mixing or scalar dissipation rate. The conditional averages show that differential diffusion is negatively correlated with turbulent mixing. Moreover, the local turbulent Reynolds number is insufficient to estimate the magnitude of the differential diffusion effect. Alternatively, the Karlovitz number provides a better indicator of the importance of differential diffusion. A comparison of the variations of differential diffusion, turbulent mixing, heat release rate and probability of encountering explosive zones demonstrates that differential diffusion predominantly plays an important role for mixture preparation and initiation of chemical reactions, closely followed by intense chemical reactions sustained by sufficient downstream turbulent mixing. The mechanism by which differential diffusion contributes to mixture preparation is investigated using the Takeno Flame Index. The mean Flame Index, based on the combined fuel species, shows that the overall extent of premixing is not intense in the upstream regions. However, the Flame Index computed based on individual contribution of H 2 or CO species reveals that hydrogen contributes significantly to premixing, particularly in explosive zones in the upstream leeward region, i.e. at the preferred flame stabilization location. Therefore, a small amount of H 2 diffuses much faster than CO, creating relatively homogeneous mixture pockets depending on the competition with turbulent mixing. These pockets, together with high H 2 reactivity, contribute to stabilizing the flame at a consistent location regardless of the CO concentration in the fuel for the present range of DNS conditions.« less

Autonomous characterization of plastic-bonded explosives

NASA Astrophysics Data System (ADS)

Linder, Kim Dalton; DeRego, Paul; Gomez, Antonio; Baumgart, Chris

2006-08-01

Plastic-Bonded Explosives (PBXs) are a newer generation of explosive compositions developed at Los Alamos National Laboratory (LANL). Understanding the micromechanical behavior of these materials is critical. The size of the crystal particles and porosity within the PBX influences their shock sensitivity. Current methods to characterize the prominent structural characteristics include manual examination by scientists and attempts to use commercially available image processing packages. Both methods are time consuming and tedious. LANL personnel, recognizing this as a manually intensive process, have worked with the Kansas City Plant / Kirtland Operations to develop a system which utilizes image processing and pattern recognition techniques to characterize PBX material. System hardware consists of a CCD camera, zoom lens, two-dimensional, motorized stage, and coaxial, cross-polarized light. System integration of this hardware with the custom software is at the core of the machine vision system. Fundamental processing steps involve capturing images from the PBX specimen, and extraction of void, crystal, and binder regions. For crystal extraction, a Quadtree decomposition segmentation technique is employed. Benefits of this system include: (1) reduction of the overall characterization time; (2) a process which is quantifiable and repeatable; (3) utilization of personnel for intelligent review rather than manual processing; and (4) significantly enhanced characterization accuracy.

Explosive Deep Sea Volcanism Produces Composite Volcanoes (Stratocones) with Predominantly Diffuse Flow Hydrothermal Ecosystems

NASA Astrophysics Data System (ADS)

Rubin, K. H.; Chadwick, W. C.; Embley, R. W.; Butterfield, D. A.

2018-05-01

Newly-discovered extensive explosive deep sea volcanism produces distinct stratovolcano structures and physical rock characteristics, and host primarily diffuse flow hydrothermal activity, unlike focused flow systems at effusive submarine volcanoes.

Metallic glass formation at the interface of explosively welded Nb and stainless steel

NASA Astrophysics Data System (ADS)

Bataev, I. A.; Hokamoto, K.; Keno, H.; Bataev, A. A.; Balagansky, I. A.; Vinogradov, A. V.

2015-07-01

The interface between explosively welded niobium and stainless steel SUS 304 was studied using scanning electron microscopy, transmission electron microscopy and energy dispersive X-Ray spectroscopy. The wavy interface along which vortex zones were located was observed. The vortex zones formed due to the mixing of materials typically had amorphous structure. Inoue's criteria of glass formation were used to explain this result. The effect of the composition, cooling rate and pressure on the glass formation are discussed. The conditions of deformation, heating, and cooling as well as shockwaves propagation were numerically simulated. We show that the conditions of vortex zone formation resemble the conditions of rapid solidification processes. In contrast to the "classical" methods of rapid solidification of melt, the conditions of metastable phase formation during explosive welding are significantly complicated by the fluctuations of composition and pressure. Possible metastable structures formation at the interface of some common explosively joined materials is predicted.

Interface morphology and mechanical properties of Al-Cu-Al laminated composites fabricated by explosive welding and subsequent rolling process

NASA Astrophysics Data System (ADS)

Hoseini-Athar, M. M.; Tolaminejad, B.

2016-07-01

Explosive welding is a well-known solid state method for joining similar and dissimilar materials. In the present study, tri-layered Al-Cu-Al laminated composites with different interface morphologies were fabricated by explosive welding and subsequent rolling. Effects of explosive ratio and rolling thickness reduction on the morphology of interface and mechanical properties were evaluated through optical/scanning electron microscopy, micro-hardness, tensile and tensile-shear tests. Results showed that by increasing the thickness reduction, bonding strength of specimens including straight and wavy interfaces increases. However, bonding strength of the specimens with melted layer interface decreases up to a threshold thickness reduction, then rapidly increases by raising the reduction. Hardness Values of welded specimens were higher than those of original material especially near the interface and a more uniform hardness profile was obtained after rolling process.

Explosive Welding in the 1990's

NASA Technical Reports Server (NTRS)

Lalwaney, N. S.; Linse, V. D.

1985-01-01

Explosive bonding is a unique joining process with the serious potential to produce composite materials capable of fulfilling many of the high performance materials capable of fulfilling many of the high performance materials needs of the 1990's. The process has the technological versatility to provide a true high quality metallurgical compatible and incompatible systems. Metals routinely explosively bonded include a wide variety of combinations of reactive and refractory metals, low and high density metals and their alloys, corrosion resistant and high strength alloys, and common steels. The major advantage of the process is its ability to custom design and engineer composites with physical and/or mechanical properties that meet a specific or unusual performance requirement. Explosive bonding offers the designer unique opportunities in materials selection with unique combinations of properties and high integrity bonds that cannot be achieved by any other metal joining process. The process and some applications are discussed.

Advanced emergency openings for commercial aircraft

NASA Technical Reports Server (NTRS)

Bement, L. J.; Schimmel, M. L.

1985-01-01

Explosively actuated openings in composite panels are proposed to enhance passenger survivability within commercial aircraft by providing improvements in emergency openings, fuselage venting, and fuel dump. The concept is to embed a tiny, highly stable explosive cord in the periphery of a load-carrying composite panel; on initiation of the cord, the panel is fractured to create a well-defined opening. The panel would be installed in the sides of the fuselage for passenger egress, in the top of the fuselage for smoke venting, and in the bottoms of the fuel cells for fuel dump. Described are the concerns with the use of explosive systems, safety improvements, advantages, experimental results, and recommended approach to gain acceptance and develop this concept.

Avian community composition in response to high explosive testing operations at Los Alamos National Laboratory in Northern New Mexico

DOE PAGES

Keller, David C.; Fresquez, Philip R.; Hansen, Leslie A.; ...

2015-12-28

Breeding bird abundance, species richness, evenness, diversity, composition, productivity, and survivorship were determined near a high-explosive detonation site at Los Alamos National Laboratory, New Mexico, USA, during pre-operation (1997-1999) and operation (2000-2014) periods. The operation periods consisted of detonations (<23 kg in yield and <3 per breeding season) in open air (2000-2002), within foam containment (2003-2006) and within steel vessel containment (2007-2014) systems; the latter two were employed to reduce noise and dispersal of high-explosives residues. A total of 2952 bird captures, representing 80 species, was recorded during 18 years of mist net operations using the Monitoring Avian Productivity andmore » Survivorship protocol. Individuals captured were identified to species, aged, sexed, and banded during May through August of each year. There were no significant differences (p > 0.05) in mean avian abundance and species evenness in any of the operation periods as compared with the pre-operation period. Species richness and diversity were significantly higher (p < 0.05) during the vessel containment period (2007-2014) than the pre-operation period. The time period of this study coincided with a wildfire (2000), a bark beetle infestation (2002), and two periods of drought (Nov 1999-Mar 2004 and Dec 2005-Dec 2014) that affected the study area. Furthermore, analysis of aerial photos determined that the average percent canopy cover of mature ponderosa pines (Pinus ponderosa) within 100 feet of mist net sites declined from 12% to 3% between 1991 and 2014 and the percent cover of shrubs slightly increased.« less

Variations in eruptive style and depositional processes of Neoproterozoic terrestrial volcano-sedimentary successions in the Hamid area, North Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Khalaf, Ezz El Din Abdel Hakim

2013-07-01

Two contrasting Neoproterozoic volcano-sedimentary successions of ca. 600 m thickness were recognized in the Hamid area, Northeastern Desert, Egypt. A lower Hamid succession consists of alluvial sediments, coherent lava flows, pyroclastic fall and flow deposits. An upper Hamid succession includes deposits from pyroclastic density currents, sills, and dykes. Sedimentological studies at different scales in the Hamid area show a very complex interaction of fluvial, eruptive, and gravitational processes in time and space and thus provided meaningful insights into the evolution of the rift sedimentary environments and the identification of different stages of effusive activity, explosive activity, and relative quiescence, determining syn-eruptive and inter-eruptive rock units. The volcano-sedimentary deposits of the study area can be ascribed to 14 facies and 7 facies associations: (1) basin-border alluvial fan, (2) mixed sandy fluvial braid plain, (3) bed-load-dominated ephemeral lake, (4) lava flows and volcaniclastics, (5) pyroclastic fall deposits, (6) phreatomagmatic volcanic deposits, and (7) pyroclastic density current deposits. These systems are in part coeval and in part succeed each other, forming five phases of basin evolution: (i) an opening phase including alluvial fan and valley flooding together with a lacustrine period, (ii) a phase of effusive and explosive volcanism (pulsatory phase), (iii) a phase of predominant explosive and deposition from base surges (collapsing phase), and (iv) a phase of caldera eruption and ignimbrite-forming processes (climactic phase). The facies architectures record a change in volcanic activity from mainly phreatomagmatic eruptions, producing large volumes of lava flows and pyroclastics (pulsatory and collapsing phase), to highly explosive, pumice-rich plinian-type pyroclastic density current deposits (climactic phase). Hamid area is a small-volume volcano, however, its magma compositions, eruption styles, and inter-eruptive breaks suggest, that it closely resembles a volcanic architecture commonly associated with large, composite volcanoes.

SUPERFUND TREATABILITY CLEARINGHOUSE: COMPOSITING EXPLOSIVES/ORGANICS CONTAMINATED SOILS

EPA Science Inventory

Laboratory scale and pilot scale studies were conducted to evaluate composting to treat sediments and soils containing explosive and organic compounds. Sediment and soil from lagoons at Army ammunition plants, located in Louisiana, Wisconsin and Pennsylvania contained high...

Using molecular recognition of beta-cyclodextrin to determine molecular weights of low-molecular-weight explosives by MALDI-TOF mass spectrometry.

PubMed

Zhang, Min; Shi, Zhen; Bai, Yinjuan; Gao, Yong; Hu, Rongzu; Zhao, Fenqi

2006-02-01

This study presents a novel method for determining the molecular weights of low molecular weight (MW) energetic compounds through their complexes of beta-cyclodextrin (beta-CD) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in a mass range of 500 to 1700 Da, avoiding matrix interference. The MWs of one composite explosive composed of 2,6-DNT, TNT, and RDX, one propellant with unknown components, and 14 single-compound explosives (RDX, HMX, 3,4-DNT, 2,6-DNT, 2,5-DNT, 2,4,6-TNT, TNAZ, DNI, BTTN, NG, TO, NTO, NP, and 662) were measured. The molecular recognition and inclusion behavior of beta-CD to energetic materials (EMs) were investigated. The results show that (1) the established method is sensitive, simple, accurate, and suitable for determining the MWs of low-MW single-compound explosives and energetic components in composite explosives and propellants; and (2) beta-CD has good inclusion and modular recognition abilities to the above EMs.

Raman chemical imaging of explosive-contaminated fingerprints.

PubMed

Emmons, E D; Tripathi, A; Guicheteau, J A; Christesen, S D; Fountain, A W

2009-11-01

Raman chemical imaging (RCI) has been used to detect and identify explosives in contaminated fingerprints. Bright-field imaging is used to identify regions of interest within a fingerprint, which can then be examined to determine their chemical composition using RCI and fluorescence imaging. Results are presented where explosives in contaminated fingerprints are identified and their spatial distributions are obtained. Identification of explosives is obtained using Pearson's cosine cross-correlation technique using the characteristic region (500-1850 cm(-1)) of the spectrum. This study shows the ability to identify explosives nondestructively so that the fingerprint remains intact for further biometric analysis. Prospects for forensic examination of contaminated fingerprints are discussed.

Conduit Wall Failure as a Trigger for Transition From Strombolian to Phreatomagmatic Explosive Activity in the Cova de Paúl Crater Eruption on Santo Antão, Cape Verde Islands

NASA Astrophysics Data System (ADS)

Tarff, R. W.; Day, S. J.

2011-12-01

Episodes of hazardous phreatomagmatic explosive activity, including Surtseyan activity, occur within otherwise less dangerous effusive to mildly explosive magmatic eruptions at high-elevation vents on many oceanic island volcanoes. The water driving these explosions is sourced from freshwater aquifers within the volcanic edifices. Understanding volcanic and geophysical precursors to, and mechanisms of, the (frequently abrupt) transitions to explosive activity is required as a basis for effective warning and mitigation of the resulting hazards. Here we describe near-vent deposits around the large Cova de Paúl crater on the island of Santo Antão, Cape Verde Islands, which provide some insights into a transition from mild magmatic to violently explosive phreatomagmatic activity in one such eruption. This pre-historic but well-preserved crater formed in a single eruption that produced extensive low-temperature, lithic-rich phreatomagmatic pyroclastic flows and surge deposits; these are interbedded in proximal outcrops with airfall breccia and ash beds containing varying proportions of lithic and juvenile clasts, pointing to a series of climactic explosions within an extended period of milder explosive activity of broadly Surtseyan type. Prior to the transition to phreatomagmatic activity, the eruption had been characterized by mild Strombolian activity that produced scoria and spatter deposits of broadly tephritic composition. The Strombolian deposits contain a distinct population of strongly banded, low-vesicularity angular clasts with strongly prolate vesicles and a notably glassy appearance. These became markedly larger and more abundant just below the transition to the phreatomagmatic deposits. Comparisons of these clasts with the Strombolian scoria suggest that they are fragments of flow-banded chilled margins from the walls of the eruptive conduit. Thermal shattering of these margins to produce the angular glassy clasts may record the onset of groundwater flow into the conduit, leading to the phreatomagmatic explosive phase of the eruption. Fragmentation of the conduit wall and ingress of groundwater would likely have been accompanied by seismic swarms consisting of high-frequency fracture events and episodes of harmonic tremor, pointing to a potential geophysical signature of the onset of phreatomagmatic explosive activity in comparable future eruptions on Santo Antão and other oceanic islands.

Effect of particle size and particle size distribution on physical characteristics, morphology and crystal strucutre of explosively compacted high-Tc superconductors

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

Kotsis, I.; Enisz, M.; Oravetz, D.

1994-12-31

A superconductor, of composition Y(Ba,K,Na){sub 2}Cu{sub 3}O{sub x}/F{sub y} and a composite, of composition Y(Ba,K,Na){sub 2}Cu{sub 3}O{sub x}/F{sub y}+Ag, with changing K, Na and F content, but a constant silver content (Ag=10 mass per cent) was prepared using a single heat treatment. The resulting material was ground in a corundum lined mill, separated to particle size fractions of 0-40 {mu}m, 0-63 {mu}m and 63-900 {mu}m and explosively compacted, using an explosive pressure of 10{sup 4} MPa and a subsequent heat treatment. Best results were obtained with the 63-900 {mu}m fraction of composition Y(Ba{sub 1,95}K{sub 0,01})Cu{sub 3}O{sub x}F{sub 0,05}/Ag: porosity <0.01more » cm{sup 3}/g and current density 2800 A/cm{sup 2} at 77 K.« less

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.

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

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.

Hubble Monitors Supernova In Nearby Galaxy M82

NASA Image and Video Library

2014-02-26

This is a Hubble Space Telescope composite image of a supernova explosion designated SN 2014J in the galaxy M82. At a distance of approximately 11.5 million light-years from Earth it is the closest supernova of its type discovered in the past few decades. The explosion is categorized as a Type Ia supernova, which is theorized to be triggered in binary systems consisting of a white dwarf and another star — which could be a second white dwarf, a star like our sun, or a giant star. Astronomers using a ground-based telescope discovered the explosion on January 21, 2014. This Hubble photograph was taken on January 31, as the supernova approached its peak brightness. The Hubble data are expected to help astronomers refine distance measurements to Type Ia supernovae. In addition, the observations could yield insights into what kind of stars were involved in the explosion. Hubble’s ultraviolet-light sensitivity will allow astronomers to probe the environment around the site of the supernova explosion and in the interstellar medium of the host galaxy. Because of their consistent peak brightness, Type Ia supernovae are among the best tools to measure distances in the universe. They were fundamental to the 1998 discovery of the mysterious acceleration of the expanding universe. A hypothesized repulsive force, called dark energy, is thought to cause the acceleration. Among the other major NASA space-based observatories used in the M82 viewing campaign are Spitzer Space Telescope, Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Gamma-ray Space Telescope, Swift Gamma Ray Burst Explorer, and the Stratospheric Observatory for Infrared Astronomy (SOFIA). Image Credit: NASA, ESA, A. Goobar (Stockholm University), and the Hubble Heritage Team (STScI/AURA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Detection and identification of explosive particles in fingerprints using attenuated total reflection-Fourier transform infrared spectromicroscopy.

PubMed

Mou, Yongyan; Rabalais, J Wayne

2009-07-01

The application of attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectromicroscopy for detection of explosive particles in fingerprints is described. The combined functions of ATR-FTIR spectromicroscopy are visual searching of particles in fingerprints and measuring the FTIR spectra of the particles. These functions make it possible to directly identify whether a suspect has handled explosives from the fingerprints alone. Particles in explosive contaminated fingerprints are either ingredients of the explosives, finger residues, or other foreign materials. These cannot normally be discriminated by their morphology alone. ATR-FTIR spectra can provide both particle morphology and composition. Fingerprints analyzed by ATR-FTIR can be used for further analysis and identification because of its non-destructive character. Fingerprints contaminated with three different types of explosives, or potential explosives, have been analyzed herein. An infrared spectral library was searched in order to identify the explosive residues. The acquired spectra are compared to those of finger residue alone, in order to differentiate such residue from explosive residue.

The velocity and composition of supernova ejecta

NASA Technical Reports Server (NTRS)

Colgate, S. A.

1971-01-01

In case of the Gum nebula, a pulsar - a presumed neutron star - is believed to be a relic of the supernova explosion. Regardless of the mechanism of the explosion, the velocity distribution and composition of the ejected matter will be roughly the same. The reimploding mass fraction is presumed to be neutron rich. The final composition is thought to be roughly 1/3 iron and 2/3 silicon, with many small fractions of elements from helium to iron. The termination of helium shell burning occurs because the shell is expanded and cooled by radiation stress. The mass fraction of the helium burning shell was calculated.

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.

Explosive double salts and preparation

DOEpatents

Cady, Howard H.; Lee, Kien-yin

1984-01-01

Applicants have discovered a new composition of matter which is an explosive addition compound of ammonium nitrate (AN) and diethylenetriamine trinitrate (DETN) in a 50:50 molar ratio. The compound is stable over extended periods of time only at temperatures higher than 46.degree. C., decomposing to a fine-grained eutectic mixture (which is also believed to be new) of AN and DETN at temperatures lower than 46.degree. C. The compound of the invention has an x-ray density of 1.61 g/cm.sup.3, explodes to form essentially only gaseous products, has higher detonation properties (i.e., detonation velocity and pressure) than those of any mechanical mixture having the same density and composition as the compound of the invention, is a quite insensitive explosive material, can be cast at temperatures attainable by high pressure steam, and is prepared from inexpensive ingredients. Methods of preparing the compound of the invention and the fine-grained eutectic composition of the invention are given.

A Binary Eutectic Mixture of TNAZ and R-Salt Explosives

NASA Astrophysics Data System (ADS)

Sandstrom, Mary; Manner, Virginia; Pemberton, Steven; Lloyd, Joseph; Tappan, Bryce

2011-06-01

TNAZ is a high performing explosive that is melt castable. However, the casting process can be problematic since TNAZ has a high vapor pressure exacerbated by a fairly high melting temperature. In order to mitigate the ill effects of its high vapor pressure, including a lower melting explosive was explored by making a series of mixtures of TNAZ and R-Salt. Initially, a eutectic temperature and composition was theoretically determined. Then a phase diagram was constructed from a series and mixtures by differential scanning calorimetery (DSC). The vapor pressure of the eutectic composition was determined by thermogravimetric analysis (TGA). Cylinder testing of the eutectic composition was carried out in copper tubes, 5'' long with 1/2 ``inner diameter and 1/16'' thick walls. The detonation velocity was measured using wire switches along the cylinder length and the expanding wall velocity was measured using PDV gauges. A rough evaluation of JWL equation-of-state parameters has been carried out. A more detailed evaluation is in progress.

Notes on the ExactPack Implementation of the DSD Explosive Arc Solver

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

Kaul, Ann; Doebling, Scott William

It has been shown above that the discretization scheme implemented in the ExactPack solver for the DSD Explosive Arc equation is consistent with the Explosive Arc PDE. In addition, a stability analysis has provided a CFL condition for a stable time step. Together, consistency and stability imply convergence of the scheme, which is expected to be close to first-order in time and second-order in space. It is understood that the nonlinearity of the underlying PDE will affect this rate somewhat.

Fate dynamics of environmentally exposed explosive traces.

PubMed

Kunz, Roderick R; Gregory, Kerin E; Aernecke, Matthew J; Clark, Michelle L; Ostrinskaya, Alla; Fountain, Augustus W

2012-04-12

The chemical and physical fates of trace amounts (<50 μg) of explosives containing 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and pentaerythritol tetranitrate (PETN) were determined for the purpose of informing the capabilities of tactical trace explosive detection systems. From these measurements, it was found that the mass decreases and the chemical composition changes on a time scale of hours, with the loss mechanism due to a combination of sublimation and photodegradation. The rates for these processes were dependent on the explosive composition, as well as on both the ambient temperature and the size distribution of the explosive particulates. From these results, a persistence model was developed and applied to model the time dependence of both the mass and areal coverage of the fingerprints, resulting in a predictive capability for determining fingerprint fate. Chemical analysis confirmed that sublimation rates for TNT were depressed by UV (330-400 nm) exposure due to photochemically driven increases in the molecular weight, whereas the opposite was observed for RDX. No changes were observed for PETN upon exposure to UV radiation, and this was attributed to its low UV absorbance.

Method for the decontamination of soil containing solid organic explosives therein

DOEpatents

Radtke, Corey W.; Roberto, Francisco F.

2000-01-01

An efficient method for decontaminating soil containing organic explosives ("TNT" and others) in the form of solid portions or chunks which are not ordinarily subject to effective bacterial degradation. The contaminated soil is treated by delivering an organic solvent to the soil which is capable of dissolving the explosives. This process makes the explosives more bioavailable to natural bacteria in the soil which can decompose the explosives. An organic nutrient composition is also preferably added to facilitate decomposition and yield a compost product. After dissolution, the explosives are allowed to remain in the soil until they are decomposed by the bacteria. Decomposition occurs directly in the soil which avoids the need to remove both the explosives and the solvents (which either evaporate or are decomposed by the bacteria). Decomposition is directly facilitated by the solvent pre-treatment process described above which enables rapid bacterial remediation of the soil.

Compact chemical energy system for seismic applications

DOEpatents

Engelke, Raymond P.; Hedges, Robert O.; Kammerman, Alan B.; Albright, James N.

1998-01-01

A chemical energy system is formed for producing detonations in a confined environment. An explosive mixture is formed from nitromethane (NM) and diethylenetriamine (DETA). A slapper detonator is arranged adjacent to the explosive mixture to initiate detonation of the mixture. NM and DETA are not classified as explosives when handled separately and can be safely transported and handled by workers in the field. In one aspect of the present invention, the chemicals are mixed at a location where an explosion is to occur. For application in a confined environment, the chemicals are mixed in an inflatable container to minimize storage space until it is desired to initiate an explosion. To enable an inflatable container to be used, at least 2.5 wt % DETA is used in the explosive mixture. A barrier is utilized that is formed of a carbon composite material to provide the appropriate barrel geometry and energy transmission to the explosive mixture from the slapper detonator system.

Layered, massive and thin sediments on Mars: Possible Late Noachian to Late Amazonian tephra?

USGS Publications Warehouse

Chapman, M.G.

2002-01-01

Data from instruments on the currently orbiting Mars Global Surveyor (MGS) suggest that as an alternative interpretation to lacustrine deposits, widespread sediments on Mars may be tephra deposits of variable age, formed in part by volcano-ice interactions. The materials are often associated with outcrops of mapped geological units that have each been previously interpreted as volcanic ash deposits with identified, but unconfirmed possible volcanic vents. Spectral investigation indicates that although some outcrops are basaltic, many show moderate to high concentrations of andesite, a composition at which large explosive eruptions may be possible. In addition, many outcrops are in areas suspected to be water/ice rich. On Earth, magma and groundwater can react to create violent explosive eruptions. Observations from MGS support a pyroclastic mechanism of deposition and show some morphologies consistent with volcano-ice interactions, including subaqueous eruptions. Perhaps MGS data are finally producing more definitive evidence of the widespread tephra that were predicted to be likely in the reduced atmospheric pressure of Mars.

UH cosmic rays and solar system material - The elements just beyond iron

NASA Technical Reports Server (NTRS)

Wefel, J. P.; Schramm, D. N.; Blake, J. B.

1977-01-01

The nucleosynthesis of cosmic-ray elements between the iron peak and the rare-earth region is examined, and compositional changes introduced by propagation in interstellar space are calculated. Theories on the origin of elements heavier than iron are reviewed, a supernova model of explosive nucleosynthesis is adopted for the ultraheavy (UH) cosmic rays, and computational results for different source distributions are compared with experimental data. It is shown that both the cosmic-ray data and the nucleosynthesis calculations are not yet of sufficient precision to pinpoint the processes occurring in cosmic-ray source regions, that the available data do provide boundary conditions for cosmic-ray nucleosynthesis, and that these limits may apply to the origin of elements in the solar system. Specifically, it is concluded that solar-system abundances appear to be consistent with a superposition of the massive-star core-helium-burning s-process plus explosive-carbon-burning synthesis for the elements from Cu to As and are explained adequately by the s- and r-processes for heavier elements.

Low vulnerability explosives (LOVEX) for mass-use warheads

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

Pruneda, C.; Jessop, E.; McGuire, R.

1990-03-13

There is an ongoing effort at Lawrence Livermore National Laboratory to develop explosives with a significantly lower vulnerability to battlefield environments (bullets, fragments, sympathetic detonation) than current explosives (TNT and Comp B) without sacrificing performance or increasing costs. The approach taken is to develop a composite explosive which is comprised of inexpensive fillers such as RDX, NaNO{sub 3}, Al and a low modulus binder system. The binder system uses nitroglycerin/triacetin as an energetic plasticizer. This paper discusses the experimental results to date in vulnerability, performance and processing. 7 refs., 8 figs., 6 tabs.

A reactive flow model with coupled reaction kinetics for detonation and combustion in non-ideal explosives

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

Miller, P.J.

1996-07-01

A new reactive flow model for highly non-ideal explosives and propellants is presented. These compositions, which contain large amounts of metal, upon explosion have reaction kinetics that are characteristic of both fast detonation and slow metal combustion chemistry. A reaction model for these systems was incorporated into the two-dimensional, finite element, Lagrangian hydrodynamic code, DYNA2D. A description of how to determine the model parameters is given. The use of the model and variations are applied to AP, Al, and nitramine underwater explosive and propellant systems.

Explosive complexes

DOEpatents

Huynh, My Hang V [Los Alamos, NM

2009-09-22

Lead-free primary explosives of the formula [M.sup.II(A).sub.R(B.sup.X).sub.S](C.sup.Y).sub.T, where A is 1,5-diaminotetrazole, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

Explosive complexes

DOEpatents

Huynh, My Hang V [Los Alamos, NM

2011-08-16

Lead-free primary explosives of the formula [M.sup.II(A).sub.R(B.sup.X).sub.S](C.sup.Y).sub.T, where A is 1,5-diaminotetrazole, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

Temperature and pressure influence on explosion pressures of closed vessel propane-air deflagrations.

PubMed

Razus, Domnina; Brinzea, Venera; Mitu, Maria; Oancea, Dumitru

2010-02-15

An experimental study on pressure evolution during closed vessel explosions of propane-air mixtures was performed, for systems with various initial concentrations and pressures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.2 bar). The explosion pressures and explosion times were measured in a spherical vessel (Phi=10 cm), at various initial temperatures (T(0)=298-423 K) and in a cylindrical vessel (Phi=10 cm; h=15 cm), at ambient initial temperature. The experimental values of explosion pressures are examined against literature values and compared to adiabatic explosion pressures, computed by assuming chemical equilibrium within the flame front. The influence of initial pressure, initial temperature and fuel concentration on explosion pressures and explosion times are discussed. At constant temperature and fuel/oxygen ratio, the explosion pressures are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, both the measured and calculated (adiabatic) explosion pressures are linear functions of reciprocal value of initial temperature. Such correlations are extremely useful for predicting the explosion pressures of flammable mixtures at elevated temperatures and/or pressures, when direct measurements are not available.

Minutes of the Explosives Safety Seminar (19th) Held at Los Angeles, California, 9-10-11 September 1980. Volume 1

DTIC Science & Technology

1980-01-01

DOUBLE-BASE EXTRUSION COMPOSITIONS ................................... 89 Messrs. Craig E. Johnson and Paul F. Dendor V I GUN PROPELLANT PROPAGATION IN...Mullins and C. F. Baker RESULTS AND ANALYSIS OF STRENGTHENED STEEL BUILDING BLAST TESTS ..... 165 Messrs. Frederic E. Sock, Norval Dobbs, Paul Price and...347 Mr. J. Paul Glenn I viLR SESSION - EXPLOSION CONTAIMENT & VENTING Moderator - Mr. Irving Forsten EXPLOSION CONTAINMENT VESSELS AND M4TERIALS

Equations of State and High-Pressure Phases of Explosives

NASA Astrophysics Data System (ADS)

Peiris, Suhithi M.; Gump, Jared C.

Energetic materials, being the collective name for explosives, propellants, pyrotechnics, and other flash-bang materials, span a wide range of composite chemical formulations. Most militarily used energetics are solids composed of particles of the pure energetic material held together by a binder. Commonly used binders include various oils, waxes, and polymers or plasticizers, and the composite is melt cast, cured, or pressed to achieve the necessary mechanical properties (gels, putties, sheets, solid blocks, etc.) of the final energetic material. Mining, demolition, and other industries use liquid energetics that are similarly composed of an actual energetic material or oxidizer together with a fuel, that is to be mixed and poured for detonation. Pure energetic materials that are commonly used are nitroglycerine, ammonium nitrate, ammonium or sodium perchlorate, trinitrotoluene (TNT), HMX, RDX, and TATB. All of them are molecular materials or molecular ions that when initiated or insulted undergoes rapid decomposition with excessive liberation of heat resulting in the formation of stable final products. When the final products are gases, and they are rapidly produced, the sudden pressure increase creates a shock wave. When decomposition is so rapid that the reaction moves through the explosive faster than the speed of sound in the unreacted explosive, the material is said to detonate. Typically, energetic materials that undergo detonation are known as high explosives (HEs) and energetic materials that burn rapidly or deflagrate are known as low explosives and/or propellants.

Effect of Heat Treatment on the Structure and Properties of Explosion Welded Bimetal Kh20N80 + AD1

NASA Astrophysics Data System (ADS)

Shmorgun, V. G.; Arisova, V. N.; Slautin, O. V.; Taube, A. O.; Bakuntseva, V. M.

2017-05-01

Results of a study of the effect of heat treatment on the microhardness, structure and phase composition of diffusion zone in explosion-welded `refractory nickel alloy Kh20N80 + aluminum alloy AD1' bimetal are presented.

Lead-free primary explosives

DOEpatents

Huynh, My Hang V.

2010-06-22

Lead-free primary explosives of the formula (cat).sub.Y[M.sup.II(T).sub.X(H.sub.2O).sub.6-X].sub.Z, where T is 5-nitrotetrazolate, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

77 FR 57593 - Agency Information Collection Activities: Proposed Collection; Comments Requested: Furnishing of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-18

... import explosive materials or ammonium nitrate must, when required by the Director, furnish samples of such explosive materials or ammonium nitrate; information on chemical composition of those products... ammonium nitrate. (5) An estimate of the total number of respondents and the amount of time estimated for...

Explosive activity associated with the growth of volcanic domes

USGS Publications Warehouse

Newhall, C.G.; Melson, W.G.

1983-01-01

Domes offer unique opportunities to measure or infer the characteristics of magmas that, at domes and elsewhere, control explosive activity. A review of explosive activity associated with historical dome growth shows that: 1. (1) explosive activity has occurred in close association with nearly all historical dome growth; 2. (2) whole-rock SiO2 content, a crude but widely reported indicator of magma viscosity, shows no systematic relationship to the timing and character of explosions; 3. (3) the average rate of dome growth, a crude indicator of the rate of supply of magma and volatiles to the near-surface enviornment, shows no systematic relationship to the timing or character of explosions; and 4. (4) new studies at Arenal and Mount St. Helens suggest that water content is the dominant control on explosions from water-rich magmas, whereas the crystal content and composition of the interstitial melt (and hence magma viscosity) are equally or more important controls on explosions from water-poor magmas. New efforts should be made to improve current, rather limited techniques for monitoring pre-eruption volatile content and magma viscosity, and thus the explosive potential of magmas. ?? 1983.

[Effect of high impact movements on body composition, strength and bone mineral density on women over 60 years].

PubMed

Ramírez-Villada, Jhon F; León-Ariza, Henry H; Argüello-Gutiérrez, Yenny P; Porras-Ramírez, Keyla A

2016-01-01

Osteoporosis is characterised by loss of bone mass and deterioration of bone tissue microarchitecture that leads to fragility related to the risk of fractures. The aim of the study is to analyse the effects of a training program based on explosive movements and impact, assessed in a swimming pool, on body composition, explosive strength and bone mineral density in women over 60 years old. A total of 35 healthy physically active women (60±4.19 years) were divided into a training pool group using multi jumps (JG) and a control group (CG). JG trained for 24 weeks, 3 times a week, an hour and a half per session. Body composition testing, explosive strength, and bone mineral density were assessed before and after the program. There were differences in the explosive force (JG vs CG=P<.05 to .001) and the estimated power (JG vs CG=P<.05 to .002) between JG vs CG, with significant increases in JG. There were no significant differences in the percentage of fat and lean mass, bone mineral density lumbar and femoral between groups, although slightly significant increases in bone mineral density lumbar and femoral could be seen in JG after program implementation (JG pre-test vs JG post- test=P<.05). The training program with impact and explosive movements assessed in a pool induces gains in muscle strength and power with slight adaptations in body mass index in women over 60 years. Copyright © 2015 SEGG. Published by Elsevier Espana. All rights reserved.

Consistency of cosmic-ray source abudances with explosive nucleosynthesis

NASA Technical Reports Server (NTRS)

Kozlovsky, B.; Ramaty, R.

1973-01-01

A model was examined in which the cosmic ray abundances of elements from C to Fe are consistent with explosive nucleosynthesis. The observed abundance of cosmic rays near the earth, cosmic ray source abundance, and solar system abundance are discussed along with the ratios of cosmic ray sources to the solar system abundances.

Evaluation of active and passive near-millimeter-wave radiometric imaging techniques for detection of concealed objects

NASA Astrophysics Data System (ADS)

Reber, E. E.; Foote, F. B.; Schellenbaum, R. L.; Bradley, R. G.

1981-07-01

The potential of radiometric imaging technique to detect shielded nuclear materials and explosives carried covertly by personnel was investigated. This method of detecting contraband depends upon the differences in emissivity and reflectivity of the contraband relative to human tissue. Explosives, unlike metals and metal composites, generally have high emissivities and low reflectivities that closely approximate those of human tissue making explosives difficult to detect. Samples of several common types of explosives (TNT, Detasheet, C4, and several types of water gels) were examined at the 1.4- and 3-mm wavelengths using active and passive radiometeric techniques.

Plasmonic enhanced terahertz time-domain spectroscopy system for identification of common explosives

NASA Astrophysics Data System (ADS)

Demiraǧ, Yiǧit; Bütün, Bayram; Özbay, Ekmel

2017-05-01

In this study, we present a classification algorithm for terahertz time-domain spectroscopy systems (THz-TDS) that can be trained to identify most commonly used explosives (C4, HMX, RDX, PETN, TNT, composition-B and blackpowder) and some non-explosive samples (lactose, sucrose, PABA). Our procedure can be used in any THz-TDS system that detects either transmission or reflection spectra at room conditions. After preprocessing the signal in low THz regime (0.1 - 3 THz), our algorithm takes advantages of a latent space transformation based on principle component analysis in order to classify explosives with low false alarm rate.

Multispectral Observations of Explosive Gas Emissions from Santiaguito, Guatemala

NASA Astrophysics Data System (ADS)

Carn, S. A.; Watson, M.; Thomas, H.; Rodriguez, L. A.; Campion, R.; Prata, F. J.

2016-12-01

Santiaguito volcano, Guatemala, has been persistently active for decades, producing frequent explosions from its actively growing lava dome. Repeated release of volcanic gases contains information about conduit processes during the cyclical explosions at Santiaguito, but the composition of the gas phase and the amount of volatiles released in each explosion remains poorly constrained. In addition to its persistent activity, Santiaguito offers an exceptional opportunity to investigate lava dome degassing processes since the upper surface of the active lava dome can be viewed from the summit of neighboring Santa Maria. In January 2016 we conducted multi-spectral observations of Santiaguito's explosive eruption plumes and passive degassing from multiple perspectives as part of the first NSF-sponsored `Workshop on Volcanoes' instrument deployment. Gas measurements included open-path Fourier-Transform infrared (OP-FTIR) spectroscopy from the Santa Maria summit, coincident with ultraviolet (UV) and infrared (IR) camera and UV Differential Optical Absorption Spectroscopy (DOAS) from the El Mirador site below Santiaguito's active Caliente lava dome. Using the OP-FTIR in passive mode with the Caliente lava dome as the source of IR radiation, we were able to collect IR spectra at high temporal resolution prior to and during two explosions of Santiaguito on 7-8 January, with volcanic SO2 and H2O emissions detected. UV and IR camera data provide constraints on the total SO2 burden in the emissions (and potentially the volcanic ash burden), which coupled with the FTIR gas ratios provides new constraints on the mass and composition of volatiles driving explosions at Santiaguito. All gas measurements indicate significant volatile release during explosions with limited degassing during repose periods. In this presentation we will present ongoing analysis of the unique Santiaguito gas dataset including estimation of the total volatile mass released in explosions and an intercomparison of SO2 amounts recorded by the UV and IR instruments.

New directions in the science and technology of advanced sheet explosive formulations and the key energetic materials used in the processing of sheet explosives: Emerging trends.

PubMed

Talawar, M B; Jangid, S K; Nath, T; Sinha, R K; Asthana, S N

2015-12-30

This review presents the work carried out by the international community in the area of sheet explosive formulations and its applications in various systems. The sheet explosive is also named as PBXs and is a composite material in which solid explosive particles like RDX, HMX or PETN are dispersed in a polymeric matrix, forms a flexible material that can be rolled/cut into sheet form which can be applied to any complex contour. The designed sheet explosive must possess characteristic properties such as flexible, cuttable, water proof, easily initiable, and safe handling. The sheet explosives are being used for protecting tanks (ERA), light combat vehicle and futuristic infantry carrier vehicle from different attacking war heads etc. Besides, sheet explosives find wide applications in demolition of bridges, ships, cutting and metal cladding. This review also covers the aspects such as risks and hazard analysis during the processing of sheet explosive formulations, effect of ageing on sheet explosives, detection and analysis of sheet explosive ingredients and the R&D efforts of Indian researchers in the development of sheet explosive formulations. To the best of our knowledge, there has been no review article published in the literature in the area of sheet explosives. Copyright © 2015 Elsevier B.V. All rights reserved.

An Improved Shock Model for Bare and Covered Explosives

NASA Astrophysics Data System (ADS)

Scholtes, Gert; Bouma, Richard

2017-06-01

TNO developed a toolbox to estimate the probability of a violent event on a ship or other platform, when the munition bunker is hit by e.g. a bullet or fragment from a missile attack. To obtain the proper statistical output, several millions of calculations are needed to obtain a reliable estimate. Because millions of different scenarios have to be calculated, hydrocode calculations cannot be used for this type of application, but a fast and good engineering solutions is needed. At this moment the Haskins and Cook-model is used for this purpose. To obtain a better estimate for covered explosives and munitions, TNO has developed a new model which is a combination of the shock wave model at high pressure, as described by Haskins and Cook, in combination with the expanding shock wave model of Green. This combined model gives a better fit with the experimental values for explosives response calculations, using the same critical energy fluence values for covered as well as for bare explosives. In this paper the theory is explained and results of the calculations for several bare and covered explosives will be presented. To show this, the results will be compared with the experimental values from literature for composition B, Composition B-3 and PBX-9404.

Experimental Study and Fractal Analysis on the Anisotropic Performance of Explosively Welded Interfaces of 304 Stainless Steel/245 Carbon Steel

NASA Astrophysics Data System (ADS)

Fu, Yanshu; Qiu, Yaohui; Li, Yulong

2018-03-01

The mechanical anisotropy of an explosive welding composite plate made of 304 stainless steel/245 steel was studied through shear experiments performed on explosively welded wavy interfaces along several orientation angles. The results indicated that the strength and the fracture energy of samples significantly varied with the orientation angles. The fracture surfaces of all samples were observed using a scanning electron microscope and through three-dimensional structure microscopy. The periodic features of all the fracture surfaces were clearly shown in different fracture modes. The fractal dimension of the fracture surfaces was calculated based on the fractal geometry by the box-counting method in MATLAB. The cohesive element model was used to analyze the fracture energy according to the physical dependence of the fractal dimension on thermodynamic entropy and interface separation energy. The fracture energy was an exponential function of the fractal dimension value, which was in good agreement with the experimental results. All results were validated for effective use in the application of anisotropy analysis to the welded interface and structural optimization of explosively welded composite plates.

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.

Experimental Study and Fractal Analysis on the Anisotropic Performance of Explosively Welded Interfaces of 304 Stainless Steel/245 Carbon Steel

NASA Astrophysics Data System (ADS)

Fu, Yanshu; Qiu, Yaohui; Li, Yulong

2018-05-01

The mechanical anisotropy of an explosive welding composite plate made of 304 stainless steel/245 steel was studied through shear experiments performed on explosively welded wavy interfaces along several orientation angles. The results indicated that the strength and the fracture energy of samples significantly varied with the orientation angles. The fracture surfaces of all samples were observed using a scanning electron microscope and through three-dimensional structure microscopy. The periodic features of all the fracture surfaces were clearly shown in different fracture modes. The fractal dimension of the fracture surfaces was calculated based on the fractal geometry by the box-counting method in MATLAB. The cohesive element model was used to analyze the fracture energy according to the physical dependence of the fractal dimension on thermodynamic entropy and interface separation energy. The fracture energy was an exponential function of the fractal dimension value, which was in good agreement with the experimental results. All results were validated for effective use in the application of anisotropy analysis to the welded interface and structural optimization of explosively welded composite plates.

Investigation on the Interface Morphologies of Explosive Welding of Inconel 625 to Steel A516 Plates

NASA Astrophysics Data System (ADS)

Mousavi, S. A. A. Akbari; Zareie, H. R.

2011-01-01

The purpose of this study is to produce composite plates by explosive cladding process. This is a process in which the controlled energy of explosives is used to create a metallic bond between two similar or dissimilar materials. The welding conditions were tailored through parallel geometry route with different operational parameters. In this investigation, a two-pronged study was adopted to establish the conditions required for producing successful solid state welding: (a) Analytical calculations to determine the weldability domain or welding window; (b) Metallurgical investigations of explosive welding experiments carried out under different explosive ratios to produce both wavy and straight interfaces. The analytical calculations confirm the experimental results. Optical microscopy studies show that a transition from a smooth to wavy interface occurs with an increase in explosive ratio. SEM studies show that the interface was outlined by characteristic sharp transition between two materials.

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

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.

In this paper, we investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking onlymore » $$(\\alpha ,\\gamma )$$ reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles; inconsistent thermodynamic evolution, including misestimation of expansion timescales; and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. Finally, we present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 $${M}_{\\odot }$$ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.« less

Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat

NASA Astrophysics Data System (ADS)

Coussens, Maya; Cassidy, Michael; Watt, Sebastian F. L.; Jutzeler, Martin; Talling, Peter J.; Barfod, Dan; Gernon, Thomas M.; Taylor, Rex; Hatter, Stuart J.; Palmer, Martin R.; Montserrat Volcano Observatory

2017-03-01

Volcanism on Montserrat (Lesser Antilles arc) has migrated southwards since the formation of the Silver Hills 2.5 Ma, and has formed three successively active volcanic centres. The Centre Hills volcano was the focus of volcanism from 1-0.4 Ma, before activity commenced at the currently active Soufrière Hills volcano. The history of activity at these two volcanoes provides an opportunity to investigate the pattern of volcano behaviour on an andesitic arc island over the lifetime of individual volcanoes. Here, we describe the pyroclastic stratigraphy of subaerial exposures around central Montserrat; identifying 11 thick (> 1 m) pumiceous units derived from sustained explosive eruptions of Centre Hills from 0.8-0.4 Ma. Over 10 other, less well- exposed pumiceous units have also been identified. The pumice-rich units are interbedded with andesite lava breccias derived from effusive, dome-forming eruptions of Centre Hills. The stratigraphy indicates that large (up to magnitude 5) explosive eruptions occurred throughout the history of Centre Hills, alongside effusive activity. This behaviour at Centre Hills contrasts with Soufrière Hills, where deposits from sustained explosive eruptions are much less common and restricted to early stages of activity at the volcano, from 175-130 ka. Subsequent eruptions at Soufriere Hills have been dominated by andesitic effusive eruptions. The bulk composition, petrography and mineral chemistry of volcanic rocks from Centre Hills and Soufrière Hills are similar throughout the history of both volcanoes, except for occasional, transient departures to different magma compositions, which mark shifts in vent location or dominant eruption style. For example, the final recorded eruption of Centre Hills, before the initiation of activity at Soufrière Hills, was more silicic than any other identified eruption on Montserrat; and the basaltic South Soufrière Hills episode marked the transition to the current stage of predominantly effusive Soufrière Hills activity. The compositional stability observed throughout the history of Centre Hills and Soufrière Hills suggests that a predominance towards effusive or explosive eruption styles is not driven by major compositional shifts of magma, but may reflect local changes in long-term magma storage conditions that characterise individual episodes (on 105 year timescales) of volcanism on Montserrat. Supplementary Table 2: Complete XRF analyses for all analysed samples Supplementary Table 3: Complete ICP-MS analyses for all analysed samples. Supplementary Table 4: Plagioclase composition and precision data from SEM analysis Supplementary Table 5: Clinopyroxene composition and precision data from SEM analysis Supplementary Table 6: Orthopyroxene composition and precision data from SEM analysis Supplementary Table 7: Amphibole composition and precision data from SEM analysis Supplementary Table 8: Glass compositions from EMP analysis Supplementary Table 9: Standard Deviation of glass compositions from EMP analysis. Supplementary Table 10: Isotopic composition of argon from plagioclase crystals from select units. Data obtained using an ARGUS V multi-collector mass spectrometer.

On Presolar Stardust Grains from CO Classical Novae

NASA Astrophysics Data System (ADS)

Iliadis, Christian; Downen, Lori N.; José, Jordi; Nittler, Larry R.; Starrfield, Sumner

2018-03-01

About 30%–40% of classical novae produce dust 20–100 days after the outburst, but no presolar stardust grains from classical novae have been unambiguously identified yet. Although several studies claimed a nova paternity for certain grains, the measured and simulated isotopic ratios could only be reconciled, assuming that the grains condensed after the nova ejecta mixed with a much larger amount of close-to-solar matter. However, the source and mechanism of this potential post-explosion dilution of the ejecta remains a mystery. A major problem with previous studies is the small number of simulations performed and the implied poor exploration of the large nova parameter space. We report the results of a different strategy, based on a Monte Carlo technique, that involves the random sampling over the most important nova model parameters: the white dwarf composition; the mixing of the outer white dwarf layers with the accreted material before the explosion; the peak temperature and density; the explosion timescales; and the possible dilution of the ejecta after the outburst. We discuss and take into account the systematic uncertainties for both the presolar grain measurements and the simulation results. Only those simulations that are consistent with all measured isotopic ratios of a given grain are accepted for further analysis. We also present the numerical results of the model parameters. We identify 18 presolar grains with measured isotopic signatures consistent with a CO nova origin, without assuming any dilution of the ejecta. Among these, the grains G270_2, M11-334-2, G278, M11-347-4, M11-151-4, and Ag26 have the highest probability of a CO nova paternity.

No double detonations but core carbon ignitions in high-resolution, grid-based simulations of binary white dwarf mergers

NASA Astrophysics Data System (ADS)

Fenn, D.; Plewa, T.; Gawryszczak, A.

2016-11-01

We study the violent phase of the merger of massive binary white dwarf systems. Our aim is to characterize the conditions for explosive burning to occur, and identify a possible explosion mechanism of Type Ia supernovae. The primary components of our model systems are carbon-oxygen (C/O) white dwarfs, while the secondaries are made either of C/O or of pure helium. We account for tidal effects in the initial conditions in a self-consistent way, and consider initially well-separated systems with slow inspiral rates. We study the merger evolution using an adaptive mesh refinement, reactive, Eulerian code in three dimensions, assuming symmetry across the orbital plane. We use a corotating reference frame to minimize the effects of numerical diffusion, and solve for self-gravity using a multigrid approach. We find a novel detonation mechanism in C/O mergers with massive primaries. Here, the detonation occurs in the primary's core and relies on the combined action of tidal heating, accretion heating, and self-heating due to nuclear burning. The exploding structure is compositionally stratified, with a reverse shock formed at the surface of the dense ejecta. The existence of such a shock has not been reported elsewhere. The explosion energy (1.6 × 1051 erg) and 56Ni mass (0.86 M⊙) are consistent with an SN Ia at the bright end of the luminosity distribution, with an approximated decline rate of Δm15(B) ≈ 0.99. Our study does not support double-detonation scenarios in the case of a system with a 0.6 M⊙ helium secondary and a 0.9 M⊙ primary. Although the accreted helium detonates, it fails to ignite carbon at the base of the boundary layer or in the primary's core.

Visual detection of trace nitroaromatic explosive residue using photoluminescent metallole-containing polymers.

PubMed

Toal, Sarah J; Sanchez, Jason C; Dugan, Regina E; Trogler, William C

2007-01-01

The detection of trace explosives is important for forensic, military, and homeland security applications. Detection of widely used nitroaromatic explosives (trinitrotoluene [TNT], 2,4-dinitrotoluene [DNT], picric acid [PA]) was carried out using photoluminescent metallole-containing polymers. The method of detection is through the quenching of fluorescence of thin films of the polymer, prepared by spray coating organic solutions of the polymer, by the explosive analyte. Visual quenching of luminescence (lambda(em) approximately 400-510 nm) in the presence of the explosive is seen immediately upon illumination with near-UV light (lambda(ex)=360 nm). Detection limits were observed to be as low as 5 ng for TNT, 20 ng for DNT, and 5 ng for PA. In addition, experiments with normal production line explosives and their components show that this technology is also able to detect composition B, Pyrodex, and nitromethane. This method offers a convenient and sensitive method of detection of trace nitroaromatic explosive residue.

Integrated rheology model: Explosive Composition B-3

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

Davis, Stephen M.; Zerkle, David K.; Smilowitz, Laura B.

Composition B-3 (Comp B-3) is a high explosive formulation composed of 60/40wt% RDX (1,3,5-trinitroperhydro-1,3,5-triazine) /TNT (2,4,6 trinitrotoluene). Above approximately 78°C this formulation partially melts to form a multiphase system with solid RDX particles in a molten TNT matrix. This multiphase system presents a number of phenomena that influence its apparent viscosity. In an earlier study explosive Composition B-3 (Comp B-3, 60/40wt% RDX/TNT) was examined for evidence of yield stress using a non-isothermal falling ball viscometer and a yield stress model was proposed in this paper. An integrated viscosity model suitable for use in computational fluid dynamics (CFD) simulations is developedmore » to capture the transition from a heterogeneous solid to a Bingham viscoplastic fluid. This viscosity model is used to simulate the motion of imbedded spheres falling through molten Comp B-3. Finally, comparison of the simulations to physical tests show agreement between the positions predicted by the model and the measured locations of the spheres as a function of temperature between 90C and 165C.« less

Integrated rheology model: Explosive Composition B-3

DOE PAGES

Davis, Stephen M.; Zerkle, David K.; Smilowitz, Laura B.; ...

2018-03-20

Composition B-3 (Comp B-3) is a high explosive formulation composed of 60/40wt% RDX (1,3,5-trinitroperhydro-1,3,5-triazine) /TNT (2,4,6 trinitrotoluene). Above approximately 78°C this formulation partially melts to form a multiphase system with solid RDX particles in a molten TNT matrix. This multiphase system presents a number of phenomena that influence its apparent viscosity. In an earlier study explosive Composition B-3 (Comp B-3, 60/40wt% RDX/TNT) was examined for evidence of yield stress using a non-isothermal falling ball viscometer and a yield stress model was proposed in this paper. An integrated viscosity model suitable for use in computational fluid dynamics (CFD) simulations is developedmore » to capture the transition from a heterogeneous solid to a Bingham viscoplastic fluid. This viscosity model is used to simulate the motion of imbedded spheres falling through molten Comp B-3. Finally, comparison of the simulations to physical tests show agreement between the positions predicted by the model and the measured locations of the spheres as a function of temperature between 90C and 165C.« less

Determination of performance of non-ideal aluminized explosives.

PubMed

Keshavarz, Mohammad Hossein; Mofrad, Reza Teimuri; Poor, Karim Esmail; Shokrollahi, Arash; Zali, Abbas; Yousefi, Mohammad Hassan

2006-09-01

Non-ideal explosives can have Chapman-Jouguet (C-J) detonation pressure significantly different from those expected from existing thermodynamic computer codes, which usually allows finding the parameters of ideal detonation of individual high explosives with good accuracy. A simple method is introduced by which detonation pressure of non-ideal aluminized explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from a, b, c, d and e at any loading density without using any assumed detonation products and experimental data. Calculated detonation pressures show good agreement with experimental values with respect to computed results obtained by complicated computer code. It is shown here how loading density and atomic composition can be integrated into an empirical formula for predicting detonation pressure of proposed aluminized explosives.

Detonation Characteristics of Mixtures of HMX and Emulsion Explosives

DTIC Science & Technology

1989-04-01

and an aqueous emulsion explo- sive have been determined. The emulsion explosive consisted of amonium - nitrate , sodium- nitrate and water in the...1989 D Cb ID A Final Report C14 Approved for public release; distribution unlimited. AIR FORCE WEAPONS LABORATORY Air Force Systems Command Kirtland...TERMS (ContInue on nvwn Nf ocosury and idsŘ by block number) FIELD GROUP SUB-GROUP Explosives; Ammonium Nitrate ;- 19 01Emulsion Explosives; ( 07 04

Some features of the fabrication of multilayer fiber composites by explosive welding

NASA Technical Reports Server (NTRS)

Kotov, V. A.; Mikhaylov, A. N.; Cabelka, D.

1985-01-01

The fabrication of multilayer fiber composites by explosive welding is characterized by intense plastic deformation of the matrix material as it fills the spaces between fibers and by high velocity of the collision between matrix layers due to acceleration in the channels between fibers. The plastic deformation of the matrix layers and fiber-matrix friction provide mechanical and thermal activation of the contact surfaces, which contributes to the formation of a bond. An important feature of the process is that the fiber-matrix adhesion strength can be varied over a wide range by varying the parameters of impulsive loading.

Influence of the type of electric discharge on the properties of the produced aluminium nanoparticles

NASA Astrophysics Data System (ADS)

Shiyan, L. N.; Yavorovskii, N. A.; Pustovalov, A. V.; Gryaznova, E. N.

2015-04-01

The effect of the method of aluminum nanopowder production on the aluminum products with water reaction is described. It has been established that the interaction of aluminum nanopowder prepared by the electric wire explosion, the phase composition of the reaction products mainly consists of boehmite (AlOOH) and has a fibrous structure. Therefore, that boehmite (AlOOH) can be used for modification of polymer membranes. The modified membranes can be used as water treatment from the impurity of formed true solutions according to adsorptive mechanism, and from colloidal nanometer and micron particles according to the mechanism of mechanical separation of particles depending on sizes.

Stability of volcanic conduits: insights from magma ascent modelling and possible consequences on eruptive dynamics

NASA Astrophysics Data System (ADS)

Aravena, Alvaro; de'Michieli Vitturi, Mattia; Cioni, Raffaello; Neri, Augusto

2017-04-01

Geological evidences of changes in volcanic conduit geometry (i.e. erosive processes) are common in the volcanic record, as revealed by the occurrence of lithic fragments in most pyroclastic deposits. However, the controlling factors of conduit enlargement mechanisms are still partially unclear, as well as the influence of conduit geometry in the eruptive dynamics. Despite physical models have been systematically used for studying volcanic conduits, their mechanical stability has been poorly addressed. In order to study the mechanical stability of volcanic conduits during explosive eruptions, we present a 1D steady-state model which considers the main processes experimented by ascending magmas, such as crystallization, drag forces, fragmentation, outgassing and degassing; and the application of the Mogi-Coulomb collapse criterion, using a set of constitutive equations for studying typical cases of rhyolitic and trachytic explosive volcanism. From our results emerge that conduit stability is mainly controlled by magma rheology and conduit dimensions. Indeed, in order to be stable, feeding conduits of rhyolitic eruptions need larger radii respect to their trachytic counterparts, which is manifested in the higher eruption rates usually observed in rhyolitic explosive eruptions, as confirmed by a small compilation of global data. Additionally, for both magma compositions, we estimated a minimum magma flux for developing stable conduits (˜3ṡ106 kg/s for trachytic magmas and ˜8ṡ107 kg/s for rhyolitic magmas), which is consistent with the unsteady character commonly observed in low-mass flux events (e.g. sub-Plinian eruptions), which would be produced by episodic collapse events of the volcanic conduit, opposite to the mainly stationary high-mass flux events (e.g. Plinian eruptions), characterized by stable conduits. For a given magma composition, a minimum radius for reaching stable conditions can be computed, as a function of inlet overpressure and water content. Under the assumption that magma chamber conditions during a typical volcanic eruption follow a depressurizing trend, a continuous conduit widening process is expected. This process could explain the pervasive and continuous presence of lithic fragments in most pyroclastic deposits, even with stationary properties and conditions of the magma source (e.g. water content, temperature, composition).

UHPC for Blast and Ballistic Protection, Explosion Testing and Composition Optimization

NASA Astrophysics Data System (ADS)

Bibora, P.; Drdlová, M.; Prachař, V.; Sviták, O.

2017-10-01

The realization of high performance concrete resistant to detonation is the aim and expected outcome of the presented project, which is oriented to development of construction materials for larger objects as protective walls and bunkers. Use of high-strength concrete (HSC / HPC - “high strength / performance concrete”) and high-fiber reinforced concrete (UHPC / UHPFC -“Ultra High Performance Fiber Reinforced Concrete”) seems to be optimal for this purpose of research. The paper describes the research phase of the project, in which we focused on the selection of specific raw materials and chemical additives, including determining the most suitable type and amount of distributed fiber reinforcement. Composition of UHPC was optimized during laboratory manufacture of test specimens to obtain the best desired physical- mechanical properties of developed high performance concretes. In connection with laboratory testing, explosion field tests of UHPC specimens were performed and explosion resistance of laboratory produced UHPC testing boards was investigated.

Evaluation of cryogenic insulation materials and composites for use in nuclear radiation environments

NASA Technical Reports Server (NTRS)

Bullock, R. E.

1972-01-01

The following subjects are studied: (1) composite materials tests; (2) test of liquid level sensors and fission couples; (3) test of valve-seal materials; (4) boron epoxy composites; (5) radiation analysis of explosive materials and bifuels for RNS applications; and (6) test of thermal insulation.

Structure, phase content and mechanical properties of aluminium with hard particles after shock-wave compaction

NASA Astrophysics Data System (ADS)

Kulkov, S.; Vorozhtsov, S.; Turuntaev, I.

2015-04-01

The possibilities to combine metal and metal oxide powders in various compositions open a broad range of mechanical and thermal behavior. When using in nanostructured components the resulting materials might exhibit even more interesting properties, like product effectiveness, tensile strength, wear resistance, endurance and corrosion resistance. Intermetallics like TiAl could be obtained as TiAlx in a quality similar to that obtained from melting where only eutectic mixture can be produced. Similar effects are possible when compacting nanoceramic powders whereas these can be combined with intermetallics. Currently, it is very difficult to produce wires and special shaped parts from high temperature superconducting materials. The compacting by explosives could solve this problem.The present paper uses explosion compacting of Al nanoparticles to create nanocomposite with increased physico-mechanical properties. Russian civil explosive Uglenit was chosen as high energy material (HEM) for shock-wave compaction. The different schemes and conditions were suggested to run the explosion process. Al nanoparticles as produced by electric wire explosion contain 8-10% of aluminum oxide. That aluminum oxide can serve as strengthening material in the final nanocomposite which may be generated in various compositions by explosive compacting. Further modifications of nanocomposites were obtained when including nanodiamonds into the mixture with aluminum nanoparticles with different percentages. The addition of nanodiamonds results in a substantial strengthening effect. The experiments with compacting aluminum nanoparticles by explosives are described in detail including the process variations and conditions. The physico-mechanical properties of the nanocomposites are determined and discussed by considering the applied conditions. Especially, microstructure and phases of the obtained nanocomposites are analyzed by X-ray diffraction.

Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential

NASA Technical Reports Server (NTRS)

Keddy, Chris P.

2012-01-01

Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE.

Creation of a Data Base on Energetic Materials

DTIC Science & Technology

1987-08-10

Examples of booster explosives are Tetryl, RDX , and HMX . Examples of bursting explosives are Amatols, TNT, Compositions A, B, & C, and Picatrol. Within...Test Thermal Shock Resistance Glass Transition Temperature Toxicity Grain Size Viscosity Hardness Volatility Heat Capacity Water Resistance Heat of...Tensile Strength Flammability Thermal Conductivity Flexural Strength Thermal Expansion Coefficient Gap Test Thermal Shock Resistance Glass Transition

Thermodynamic Model of Aluminum Combustion in SDF Explosions

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

Kuhl, . L

2006-06-19

Thermodynamic states encountered during combustion of Aluminum powder in Shock-Dispersed-Fuel (SDF) explosions were analyzed with the Cheetah code. Results are displayed in the Le Chatelier diagram: the locus of states of specific internal energy versus temperature. 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 combustion in explosions.

Nitroaliphatic difluoroformals and process of manufacture

DOEpatents

Peters, H.M.; Simon, R.L. Jr.

1975-12-16

Some new nitroaliphatic difluoroformal compounds are described. The compounds are intended for use in formulating PBX compositions and as energetic plasticizers or fluidic dispersant materials for plastic explosive compositions. Methods of preparation and several examples are given. (PMA)

Infrasonic Observations of Explosions and Degassing at Kilauea Summit

NASA Astrophysics Data System (ADS)

Fee, D.; Garces, M.

2008-12-01

After 25 years of quiescence, eruptive activity returned to Kilauea Caldera with an explosion in Halema'uma'u crater on March 19th 2008. The explosion is presumed to be the clearing of a clogged vent. Along with the 3/19 explosion, at least 5 more gas-driven explosions have occurred and were clearly recorded at a 4-element infrasound array 7 km away. Acoustic energy estimates for these explosions yield energies between ~ 0.2-3 × 107 J. Infrasonic VLP energy is present for some of the explosions, but not all. The relatively long explosion durations (>20 seconds) and frequency content are consistent with a transient pressure pulse followed by the reverberation of a shallow gas chamber or conduit. Persistent degassing from Halema'uma'u followed the initial explosion. The harmonic infrasonic tremor produced by the degassing is the most energetic to date at Kilauea, with the cumulative tremor acoustic energy at ~107-108 Joules/hour. The complex tremor spectra show numerous peaks, with the dominant peak between 0.3-0.6 Hz and a smaller amplitude peak around 1-3 Hz. The peak frequency of the harmonic tremor has changed over time, which could be related to a change in the gas-filled chamber dimensions or temperature. Further analysis of the tremor spectra may help constrain dimensions. Consistent with our previous observations at Kilauea from Pu'u 'O'o, Fissure D, and lava skylights, the excitation of a gas within a confined volume appears to be the acoustic (and possibly seismic) source. For the tremor, we propose a mechanism where persistent degassing excites the gas volume into resonance. The explosions signals are consistent with a slug of gas reaching the free surface and exciting the conduit as well. Correlation of the infrasound signals with seismic tremor, LP and VLP signals suggest an open system connecting the atmosphere to the seismic excitation process at depth. Results will also be presented in relation to the recent observation of a visible lava lake within the conduit.

High Energy Explosive Yield Enhancer Using Microencapsulation.

DTIC Science & Technology

The invention consists of a class of high energy explosive yield enhancers created through the use of microencapsulation techniques. The... microcapsules consist of combinations of highly reactive oxidizers that are encapsulated in either passivated inorganic fuels or inert materials and inorganic...fuels. Depending on the application, the availability of the various oxidizers and fuels within the microcapsules can be customized to increase the

A cargo inspection system based on pulsed fast neutron analysis (PFNA).

PubMed

Ipe, N E; Olsher, R; Ryge, P; Mrozack, J; Thieu, J

2005-01-01

A cargo inspection system based on pulsed fast neutron analysis (PFNA) is to be used at a border crossing to detect explosives and contraband hidden in trucks and cargo containers. Neutrons are produced by the interaction of deuterons in a deuterium target mounted on a moveable scan arm. The collimated pulsed fast neutron beam is used to determine the location and composition of objects in a cargo container. The neutrons produce secondary gamma rays that are characteristic of the object's elemental composition. The cargo inspection system building consists of an accelerator room and an inspection tunnel. The accelerator room is shielded and houses the injector, accelerator and the neutron production gas target. The inspection tunnel is partially shielded. The truck or container to be inspected will be moved through the inspection tunnel by a conveyor system. The facility and radiation source terms considered in the shielding design are described.

Synthesis and Explosive Consolidation of Titanium, Aluminium, Boron and Carbon Containing Powders

NASA Astrophysics Data System (ADS)

Chikhradze, Mikheil; Oniashvili, George; Chikhradze, Nikoloz; D. S Marquis, Fernand

2016-10-01

The development of modern technologies in the field of materials science has increased the interest towards the bulk materials with improved physical, chemical and mechanical properties. Composites, fabricated in Ti-Al-B-C systems are characterized by unique physical and mechanical properties. They are attractive for aerospace, power engineering, machine and chemical applications. The technologies to fabricate ultrafine grained powder and bulk materials in Ti-Al-B-C system are described in the paper. It includes results of theoretical and experimental investigation for selection of powders composition and determination of thermodynamic conditions for bland preparation, as well as optimal technological parameters for mechanical alloying and adiabatic compaction. The crystalline coarse Ti, Al, C powders and amorphous B were used as precursors and blends with different compositions of Ti-Al, Ti-Al-C, Ti-B-C and Ti-Al-B were prepared. Preliminary determination/selection of blend compositions was made on the basis of phase diagrams. The powders were mixed according to the selected ratios of components to produce the blend. Blends were processed in “Fritsch” Planetary premium line ball mill for mechanical alloying, syntheses of new phases, amorphization and ultrafine powder production. The blends processing time was variable: 1 to 20 hours. The optimal technological regimes of nano blend preparation were determined experimentally. Ball milled nano blends were placed in metallic tube and loaded by shock waves for realization of consolidation in adiabatic regime. The structure and properties of the obtained ultrafine grained materials depending on the processing parameters are investigated and discussed. For consolidation of the mixture, explosive compaction technology is applied at room temperatures. The prepared mixtures were located in low carbon steel tube and blast energies were used for explosive consolidation compositions. The relationship of ball milling technological parameters and explosive consolidation conditions on the structure/properties of the obtained samples are described in the paper.

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

Steam explosion and its combinatorial pretreatment refining technology of plant biomass to bio-based products.

PubMed

Chen, Hong-Zhang; Liu, Zhi-Hua

2015-06-01

Pretreatment is a key unit operation affecting the refinery efficiency of plant biomass. However, the poor efficiency of pretreatment and the lack of basic theory are the main challenges to the industrial implementation of the plant biomass refinery. The purpose of this work is to review steam explosion and its combinatorial pretreatment as a means of overcoming the intrinsic characteristics of plant biomass, including recalcitrance, heterogeneity, multi-composition, and diversity. The main advantages of the selective use of steam explosion and other combinatorial pretreatments across the diversity of raw materials are introduced. Combinatorial pretreatment integrated with other unit operations is proposed as a means to exploit the high-efficiency production of bio-based products from plant biomass. Finally, several pilot- and demonstration-scale operations of the plant biomass refinery are described. Based on the principle of selective function and structure fractionation, and multi-level and directional composition conversion, an integrated process with the combinatorial pretreatments of steam explosion and other pretreatments as the core should be feasible and conform to the plant biomass refinery concept. Combinatorial pretreatments of steam explosion and other pretreatments should be further exploited based on the type and intrinsic characteristics of the plant biomass used, the bio-based products to be made, and the complementarity of the processes. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tephra Studies of a Violent Strombolian Cinder Cone: Parícutin, Mexico.

NASA Astrophysics Data System (ADS)

Erlund, E. J.; Pioli, L.; Delgado, H.; Cashman, K. V.; Wallace, P. J.

2006-12-01

Explosive eruptions at Parícutin volcano, Mexico, predominated throughout the first 3 years of its nine years of activity (February 1943- February 1952); effusive behaviour dominated the later years as the mass flux decreased. Explosive activity was unsteady and complex, with many blasts and explosions described in eyewitness accounts (Foshag and González, 1956). A detailed look at the tephra deposits reveals this complexity in the details of alternating ash and lapilli layers, where a single unit may consist of tens of eruptive pulses. To place the tephra sequence in the stratigraphic context provided by previous studies of dated lava flow and tephra samples (Wilcox, 1954; Luhr, 2001), we use a combination of bulk rock, matrix glass and olivine phenocryst analyses. Most obvious is the abrupt compositional shift from basaltic-andesite to andesite in 1947 (Wilcox, 1954; McBirney et al, 1987), which is also evident in the matrix glass of our tephra samples. Furthermore, measured olivine compositions of Fo86 Fo82 through the basaltic-andesite tephra sequence bracket Luhr's (2001) analyses from May 1943 to January 1945, thus confirming the completeness of the tephra record. Moreover, as both olivine and matrix glass compositions from within basal tephra layers are more primitive than previously reported analyses, we suggest that tephra deposits may provide a more complete record of the early history of mafic eruptions than the more commonly sampled lava flows. Detailed analysis of sequential tephra layers allows us to assess the relationship between eruption style and compositional change. We use two parameters to track eruption conditions: juvenile components and grain size (ash abundance). All Parícutin tephra deposits comprise three components that differ in density (vesicularity) and crystallinity: tan scoria, black scoria and lava fragments. The tan scoria is the most vesicular and least crystalline, suggesting that it represents magma that rose most quickly from depth. It is dominant to subequal in proportions with the black scoria throughout the main eruptive (basaltic andesite) sequence but decreases markedly in the andesitic section, where dense clasts dominate. In contrast, grain size changes most abruptly towards the end of the basaltic-andesite stage with the onset of thick proximal ash-rich beds prior to the obvious compositional change. An upward increase in ash in proximal locations records a progressive decrease in eruption intensity; this drop in eruption intensity prior to the eruption of andesite indicates that magma supply rate, not composition, was the primary control on eruptive style. In fact, we suggest that this decrease in magma supply rate may have permitted the extended magma storage times at shallow levels that allowed sufficient assimilation of granitic wall rocks (e.g., Wilcox, 1954) for andesite formation.

Sub-fragmentation of structural-reactive-material casings under explosion

NASA Astrophysics Data System (ADS)

Zhang, Fan

2015-06-01

The sub-fragmentation of structural reactive material (SRM) thick-casings is to generate fine fragments during casing fragmentation under explosive loading for their efficient energy release to enhance air blast. This has been investigated using a cylindrical casing made from either rich Al-MoO3 or Al-W-based granular composites. The former composite was to study the concept of reactive hot spots where the reaction of reactive particles, which were distributed into base SRM in a fuel-rich equivalence ratio, created heat and gas products during SRM fragmentation. The expansion of these distributed hot spots initiated local fractures of the casing, leading to fine fragments. The Al-W-based composite investigated the concept of impedance mismatch, where shock dynamics at the interfaces of different impedance ingredients resulted in non-uniform, high local temperatures and stresses and late in times the dissimilar inertia resulted in different accelerations, leading to material separation and fine fragments. The casings were manufactured through both hot iso-static pressing and cold gas dynamic spray deposition. Explosion experiments were conducted in a 3 m diameter, 23 m3 cylindrical chamber for these cased charges in a casing-to-explosive mass ratio of 1.75. The results demonstrated the presence of fine fragments and more efficient fragment combustion, compared with previous results, and indicated the effectiveness of both concepts. This work was jointly funded by Defence R&D Canada and the Advanced Energetics Program of DTRA (Dr. William H. Wilson).

Source and path effects in the wave fields of tremor and explosions at Stromboli Volcano, Italy

USGS Publications Warehouse

Chouet, B.; Saccorotti, G.; Martini, M.; Dawson, P.; De Luca, G.; Milana, G.; Scarpa, R.

1997-01-01

The wave fields generated by Strombolian activity are investigated using data from small-aperture seismic arrays deployed on the north flank of Stromboli and data from seismic and pressure transducers set up near the summit crater. Measurements of slowness and azimuth as a function of time clearly indicate that the sources of tremor and explosions are located beneath the summit crater at depths shallower than 200 m with occasional bursts of energy originating from sources extending to a depth of 3 km. Slowness, azimuth, and particle motion measurements reveal a complex composition of body and surface waves associated with topography, structure, and source properties. Body waves originating at depths shallower than 200 m dominate the wave field at frequencies of 0.5-2.5 Hz, and surface waves generated by the surficial part of the source and by scattering sources distributed around the island dominate at frequencies above 2.5 Hz. The records of tremor and explosions are both dominated by SH motion. Far-field records from explosions start with radial motion, and near-field records from those events show dominantly horizontal motion and often start with a low-frequency (1-2 Hz) precursor characterized by elliptical particle motion, followed within a few seconds by a high-frequency radial phase (1-10 Hz) accompanying the eruption of pyroclastics. The dominant component of the near- and far-field particle motions from explosions, and the timing of air and body wave phases observed in the near field, are consistent with a gaspiston mechanism operating on a shallow (<200 m deep), vertical crack-like conduit. Models of a degassing fluid column suggest that noise emissions originating in the collective oscillations of bubbles ascending in the magma conduit may provide an adequate self-excitation mechanism for sustained tremor generation at Stromboli. Copyright 1997 by the American Geophysical Union.

Experimental Study of Structure/Behavior Relationship for a Metallized Explosive

NASA Astrophysics Data System (ADS)

Bukovsky, Eric; Reeves, Robert; Gash, Alexander; Glumac, Nick

2017-06-01

Metal powders are commonly added to explosive formulations to modify the blast behavior. Although detonation velocity is typically reduced compared to the neat explosive, the metal provides other benefits. Aluminum is a common additive to increase the overall energy output and high-density metals can be useful for enhancing momentum transfer to a target. Typically, metal powder is homogeneously distributed throughout the material; in this study, controlled distributions of metal powder in explosive formulations were investigated. The powder structures were printed using powder bed printing and the porous structures were filled with explosives to create bulk explosive composites. In all cases, the overall ratio between metal and explosive was maintained, but the powder distribution was varied. Samples utilizing uniform distributions to represent typical materials, discrete pockets of metal powder, and controlled, graded powder distributions were created. Detonation experiments were performed to evaluate the influence of metal powder design on the output pressure/time and the overall impulse. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Infrasound Waveform Inversion and Mass Flux Validation from Sakurajima Volcano, Japan

NASA Astrophysics Data System (ADS)

Fee, D.; Kim, K.; Yokoo, A.; Izbekov, P. E.; Lopez, T. M.; Prata, F.; Ahonen, P.; Kazahaya, R.; Nakamichi, H.; Iguchi, M.

2015-12-01

Recent advances in numerical wave propagation modeling and station coverage have permitted robust inversion of infrasound data from volcanic explosions. Complex topography and crater morphology have been shown to substantially affect the infrasound waveform, suggesting that homogeneous acoustic propagation assumptions are invalid. Infrasound waveform inversion provides an exciting tool to accurately characterize emission volume and mass flux from both volcanic and non-volcanic explosions. Mass flux, arguably the most sought-after parameter from a volcanic eruption, can be determined from the volume flux using infrasound waveform inversion if the volcanic flow is well-characterized. Thus far, infrasound-based volume and mass flux estimates have yet to be validated. In February 2015 we deployed six infrasound stations around the explosive Sakurajima Volcano, Japan for 8 days. Here we present our full waveform inversion method and volume and mass flux estimates of numerous high amplitude explosions using a high resolution DEM and 3-D Finite Difference Time Domain modeling. Application of this technique to volcanic eruptions may produce realistic estimates of mass flux and plume height necessary for volcanic hazard mitigation. Several ground-based instruments and methods are used to independently determine the volume, composition, and mass flux of individual volcanic explosions. Specifically, we use ground-based ash sampling, multispectral infrared imagery, UV spectrometry, and multigas data to estimate the plume composition and flux. Unique tiltmeter data from underground tunnels at Sakurajima also provides a way to estimate the volume and mass of each explosion. In this presentation we compare the volume and mass flux estimates derived from the different methods and discuss sources of error and future improvements.

Final report for SERDP WP-2209 Replacement melt-castable formulations for Composition B

DTIC Science & Technology

2017-05-19

Chemical reaction of the materials in the melt ............................................................... 5 Thermal degradation of materials...reasons other than the hazard of explosion, these include: • Chemical reaction of the materials in the melt • Thermal degradation at low...temperature • Sublimation and condensation of explosive material on equipment and exposure to workers Chemical reaction of the materials in the melt

Bayesian Integration and Characterization of Composition C-4 Plastic Explosives Based on Time-of-Flight Secondary Ion Mass Spectrometry and Laser Ablation-Inductively Coupled Plasma Mass Spectrometry

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

Mahoney, Christine M.; Kelly, Ryan T.; Alexander, M. L.

Key elements regarding the use of non-radioactive ionization sources will be presented as related to explosives detection by mass spectrometry and ion mobility spectrometry. Various non-radioactive ionization sources will be discussed along with associated ionization mechanisms pertaining to specific sample types.

Thermal Behaviors and Their Correlations of Mg(BH4)2-Contained Explosives

NASA Astrophysics Data System (ADS)

Yue, Yue; Chen, Liping; Peng, Jinhua

2018-01-01

In order to explore the effect of metal hydride on energetic materials' thermal behaviors and their correlations, we studied the heats of combustion and detonation of RDX, TNT, and Mg(BH4)2-containing explosives both theoretically and experimentally. The results showed that Mg(BH4)2 can significantly improve the energy of explosive. As the mass fraction of Mg(BH4)2 increases, the combustion heat of composite explosives increases gradually, while the combustion efficiency decreases. When its mass fraction is about 30%, the theoretical heats of detonation of RDX/Mg(BH4)2 and TNT/Mg(BH4)2 reach maximum, which are 7418.47 and 7032.46 kJ/kg, respectively. When we compared the errors between calculation and experimental values, we found that L-C method is more accurate in calculating oxygen-enriched and oxygen-balanced explosives, and that minimum free energy method is more suitable for seriously negative oxygen-balanced explosive. For single explosive, there are three kinds of relationships between heat of combustion and detonation according to the oxygen balance. For Mg(BH4)2-containing explosives, the relationship is in accordance with Boltzmann function.

Optimum performance of explosives in a quasistatic detonation cycle

NASA Astrophysics Data System (ADS)

Baker, Ernest L.; Stiel, Leonard I.

2017-01-01

Analyses were conducted on the behavior of explosives in a quasistatic detonation cycle. This type of cycle has been proposed for the determination of the maximum work that can be performed by the explosive. The Jaguar thermochemical equilibrium program enabled the direct analyses of explosive performance at the various steps in the detonation cycle. In all cases the explosive is initially detonated to a point on the Hugoniot curve for the reaction products. The maximum useful work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmospheric pressure, minus one-half the square of the particle velocity at the detonation point. This quantity is calculated form the internal energy of the explosive at the initial and final atmospheric temperatures. Cycle efficiencies (net work/ heat added) are also calculated with these procedures. For several explosives including TNT, RDX, and aluminized compositions, maximum work effects were established through the Jaguar calculations for Hugoniot points corresponding to C-J, overdriven, underdriven and constant volume detonations. Detonation to the C-J point is found to result in the maximum net work in all cases.

Direct real-time detection of vapors from explosive compounds.

PubMed

Ewing, Robert G; Clowers, Brian H; Atkinson, David A

2013-11-19

The real-time detection of vapors from low volatility explosives including PETN, tetryl, RDX, and nitroglycerine along with various compositions containing these substances was demonstrated. This was accomplished with an atmospheric flow tube (AFT) using a nonradioactive ionization source coupled to a mass spectrometer. Direct vapor detection was accomplished in less than 5 s at ambient temperature without sample preconcentration. The several seconds of residence time of analytes in the AFT provided a significant opportunity for reactant ions to interact with analyte vapors to achieve ionization. This extended reaction time, combined with the selective ionization using the nitrate reactant ions (NO3(-) and NO3(-)·HNO3), enabled highly sensitive explosives detection from explosive vapors present in ambient laboratory air. Observed signals from diluted explosive vapors indicated detection limits below 10 ppqv using selected ion monitoring (SIM) of the explosive-nitrate adduct at m/z 349, 378, 284, and 289 for tetryl, PETN, RDX, and NG, respectively. Also provided is a demonstration of the vapor detection from 10 different energetic formulations sampled in ambient laboratory air, including double base propellants, plastic explosives, and commercial blasting explosives using SIM for the NG, PETN, and RDX product ions.

Multi-shock experiments on a TATB-based composition

NASA Astrophysics Data System (ADS)

Sorin, Remy

2017-06-01

Temperature based models for condensed explosive need an unreacted equation of state (EOS) that allows a realistic estimation of the temperature for a shock compression driven at detonation velocity. To feed the detonation models, we aim at exploring the high pressure shock Hugoniot of unreacted TATB composition up to 30 GPa with both hydrodynamic and temperature measurements. We performed on the gas gun facility ARES, multi-shock experiments where the first shock is designed to desensitize the explosive and inhibit the reactivity of the composition. The hydrodynamic behavior was measured via the velocity of a TATB/LiF interface with PDV probes. We attempted to measure the temperature of the shocked material via surface emissivity with a pyrometer calibrated to the expected low temperature range. Based on single shock experiments and on ab-initio calculation, we built a complete EOS for the unreacted phase of the TATB explosive. The hydrodynamic data are in good agreement with our unreacted EOS. Despite the record of multi-stage emissivity signals, the temperature measurements were difficult to interpret dur to high-luminisity phenomena pertubation. In collaboration with: Nicolas Desbiens, Vincent Dubois and Fabrice Gillot, CEA DAM DIF.

Comparing eruptions of varying intensity at Kilauea via melt inclusion analysis

NASA Astrophysics Data System (ADS)

Ferguson, D. J.; Plank, T. A.; Hauri, E. H.; Houghton, B. F.; Gonnermann, H. M.; Swanson, D. A.; Blaser, A. P.

2013-12-01

Over the past 500 years explosive summit eruptions from Kilauea volcano, Hawaii, have exhibited a range of eruption magnitudes, from large basaltic sub-plinian events to Hawaiian lava fountains of various intensity. Knowledge of the factors controlling such dramatic changes in explosivity and mass discharge rate is vital for understanding the dynamics of explosive basaltic magma systems, but these remain poorly constrained. At Kilauea this information also has important implications for hazard assessment, as future eruptions may be far larger than those observed historically. To investigate the processes associated with eruptions of varying magnitudes we have analyzed the composition and dissolved volatile contents (H2O-CO2-S-Cl-F) of olivine-hosted melt inclusions, sampled from tephra deposits associated with three eruptions of different sizes: a moderate lava-fountain (1959 Episode of Kilauea Iki); an exceptionally high lava-fountain (1500 CE Keanakāko'i reticulite) and a basaltic sub-plinian eruption (1650 CE Keanakāko'i layer 6 scoria). Over this time period (~500 years) we find no major shifts in the major element composition of primary melts feeding the Kilauea magmatic system, and melt inclusions from all eruptions record similar maximum water (~0.7 wt% H2O) and CO2 (~300 ppm) contents, regardless of eruption magnitude. Co-variations between other volatile species, such as CO2 and S, do not support a role for excess volatiles (i.e. CO2) in the larger eruptions via ';gas-fluxing'. Our data therefore suggests that major shifts in eruptive magnitude are unlikely to be linked to either changes in the primary volatile content of the melts or excess gas supplied by open-system degassing of deeper melts. Rather we find evidence for significant variations in the shallow degassing behavior of magmas associated with the larger Keanakāko'i eruptions (sub-plinian and strong lava-fountaining events) compared to that from less vigorous moderate Kilauea Iki lava-fountaining events. On plots of CO2 versus H2O, Kilauea Iki MI's record volatile contents consistent with equilibrium degassing of magma rising from a depth of ~3 km. In contrast, the volatile contents of melts from the more explosive eruptions appear to be strongly affected by degassing processes at shallow depths (< 300 m), indicating variations in the ascent and storage of melts over this time-period. These changes in storage conditions may be linked to variations in the depth of the summit caldera, which was significantly greater during the older more explosive eruptive phases.

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.

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.

Characterization of ANFO explosive by high accuracy ESI(±)-FTMS with forensic identification on real samples by EASI(-)-MS.

PubMed

Hernandes, Vinicius Veri; Franco, Marcos Fernado; Santos, Jandyson Machado; Melendez-Perez, Jose J; de Morais, Damila Rodrigues; Rocha, Werickson Fortunato de Carvalho; Borges, Rodrigo; de Souza, Wanderley; Zacca, Jorge Jardim; Logrado, Lucio Paulo Lima; Eberlin, Marcos Nogueira; Correa, Deleon Nascimento

2015-04-01

Ammonium nitrate fuel oil (ANFO) is an explosive used in many civil applications. In Brazil, ANFO has unfortunately also been used in criminal attacks, mainly in automated teller machine (ATM) explosions. In this paper, we describe a detailed characterization of the ANFO composition and its two main constituents (diesel and a nitrate explosive) using high resolution and accuracy mass spectrometry performed on an FT-ICR-mass spectrometer with electrospray ionization (ESI(±)-FTMS) in both the positive and negative ion modes. Via ESI(-)-MS, an ion marker for ANFO was characterized. Using a direct and simple ambient desorption/ionization technique, i.e., easy ambient sonic-spray ionization mass spectrometry (EASI-MS), in a simpler, lower accuracy but robust single quadrupole mass spectrometer, the ANFO ion marker was directly detected from the surface of banknotes collected from ATM explosion theft. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Tool and process for miniature explosive joining of tubes

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Bailey, James W. (Inventor)

1987-01-01

A tool and process to be used in the explosive joining of tubes is disclosed. The tool consists of an initiator, a tool form, and a ribbon explosive. The assembled tool is a compact, storable, and safe device suitable for explosive joining of small, lightweight tubes down to 0.20 inch in diameter. The invention is inserted into either another tube or a tube plate. A shim or standoff between the two surfaces to be welded is necessary. Initiation of the explosive inside the tube results in a high velocity, angular collision between the mating surfaces. This collision creates surface melts and collision bonding wherein electron-sharing linkups are formed.

Identification of explosives and drugs and inspection of material defects with THz radiation

NASA Astrophysics Data System (ADS)

Zhang, Cunlin; Mu, Kaijun; Jiang, Xue; Jiao, Yueying; Zhang, Liangliang; Zhou, Qingli; Zhang, Yan; Shen, Jingling; Zhao, Guoshong; Zhang, X.-C.

2008-03-01

We report the sensing of explosive materials and illicit drugs by using terahertz time-domain spectroscopy (THz-TDS) and imaging. Several explosive materials, such as γ-HNIW, RDX, 2,4-DNT, TNT, Nitro-aniline, and illicit drugs, such as methamphetamine (MA) etc were researched here. Non-destructive testing, as one of the major applications of THz imaging, can be applied to an area of critical need: the testing of aerospace materials. Composite materials such as carbon fiber are widely used in this industry. The nature of their use requires technologies that are able to differentiate between safe and unsafe materials, due to either manufacturing tolerance or damage acquired while in use. In this paper, we discuss the applicability of terahertz (THz) imaging systems to this purpose, focusing on graphite fiber composite materials, carbon silicon composite materials and so on. We applied THz imaging technology to evaluate the fire damage to a variety of carbon fiber composite samples. Major carbon fiber materials have polarization-dependent reflectivity in THz frequency range, and we show how the polarization dependence changes versus the burned damage level. Additionally, time domain information acquired through a THz time-domain spectroscopy (TDS) system provides further information with which to characterize the damage. We also detect fuel tank insulation foam panel defects with pulse and continuous-wave (CW) terahertz system.

High Temperature Perforating System for Geothermal Applications

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

Smart, Moises E.

The objective of this project is to develop a perforating system consisting of all the explosive components and hardware, capable of reliable performance in high temperatures geothermal wells (>200 ºC). In this light we will focused on engineering development of these components, characterization of the explosive raw powder and developing the internal infrastructure to increase the production of the explosive from laboratory scale to industrial scale.

The High Energy Lightning Simulator (HELS) Test Facility for Testing Explosive Items

DTIC Science & Technology

1996-08-01

Center, Redstone Arsenal, AL Thomas E. Roy and David W. Bagwell AMTEC Corporation, Huntsville, AL ABSTRACT Details of the High Energy Lightning...simulated lightning testing of inerted missiles and inerted explosive items containing electrically initiated explosive trains is to determine the...penetrate the safety cages, which are electrically conductive and grounded, without loss of current. This transmission system consists of six large

Investigation of detonation velocity in heterogeneous explosive system using the reactive Burgers' analog

NASA Astrophysics Data System (ADS)

Di Labbio, G.; Kiyanda, C. B.; Mi, X.; Higgins, A. J.; Nikiforakis, N.; Ng, H. D.

2016-06-01

In this study, the applicability of the Chapman-Jouguet (CJ) criterion is tested numerically for heterogeneous explosive media using a simple detonation analog. The analog system consists of a reactive Burgers' equation coupled with an Arrhenius type reaction wave, and the heterogeneity of the explosive media is mimicked using a discrete energy source approach. The governing equation is solved using a second order, finite-volume approach and the average propagation velocity of the discrete detonation is determined by tracking the leading shock front. Consistent with previous studies, the averaged velocity of the leading shock front from the unsteady numerical simulations is also found to be in good agreement with the velocity of a CJ detonation in a uniform medium wherein the energy source is spatially homogenized. These simulations have thus implications for whether the CJ criterion is valid to predict the detonation velocity in heterogeneous explosive media.

Three Dimensional Analysis of Induced Detonation of Cased Explosive

DTIC Science & Technology

2014-10-16

hardness and ductility . RHA steel is largely used in military applications to manufacture armoured vehicles. The Johnson Cook (JC) constitutive...armour (RHA) steel were investigated through the LS-DYNA. The investigation focused on shock to detonation simulations of Composition B, with the... hot spots caused by the compression of the explosive from the initial shockwave. Detonation was also caused by pressure waves reflecting against the

Chemical and Physical Characterization of Comp A-3 Type II Prills

DTIC Science & Technology

2013-06-01

the composition and properties of the explosive for implementation into modeling and simulation tools as part of the Multi-scale Response of...emulsion were identified using desorption-gas chromatography/mass spectroscopy (D-GC- MS) and Fourier transform infrared ( FTIR ) spectroscopy. Quantitative...understanding the microstructure of the pressed explosive and provides critical information for the development of a high fidelity particle-based course-grain

Widespread Weathered Glass on the Surface of Mars

NASA Technical Reports Server (NTRS)

Horgan, Briony; Bell, James F., III

2012-01-01

Low albedo sediments cover >10(exp 7) sq km in the northern lowlands of Mars, but the composition and origin of these widespread deposits have remained ambiguous despite many previous investigations. Here we use near-infrared spectra acquired by the Mars Express OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite') imaging spectrometer to show that these sediments exhibit spectral characteristics that are consistent with both high abundances of iron-bearing glass and silica-enriched leached rinds on glass. This interpretation is supported by observations of low-albedo soil grains with possible rinds at the Phoenix Mars Lander landing site in the northern lowlands. By comparison with the extensive glass-rich dune fields and sand sheets of Iceland, we propose an explosive volcanic origin for these glass-rich sediments. We also propose that the glassy remnant rinds on the sediments are the result of post-depositional alteration, as these rinds are commonly formed in arid terrestrial volcanic environments during water-limited, moderately acidic leaching. These weathered, glass-rich deposits in the northern lowlands are also colocated with the strongest concentrations of a major global compositional surface type previously identified in mid-infrared spectra, suggesting that they may be representative of global processes. Our results provide potential confirmation of models suggesting that explosive volcanism has been widespread on Mars, and also raise the possibilities that glass-rich volcaniclastics are a major source of eolian sand on Mars and that widespread surficial aqueous alteration has occurred under Amazonian climatic conditions.

Compressive strength after blast of sandwich composite materials

PubMed Central

Arora, H.; Kelly, M.; Worley, A.; Del Linz, P.; Fergusson, A.; Hooper, P. A.; Dear, J. P.

2014-01-01

Composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength-to-weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subjected to air blast. This paper focuses on this problem and specifically the strength remaining after damage caused during an explosion. Carbon-fibre-reinforced polymer (CFRP) composite skins on a styrene–acrylonitrile (SAN) polymer closed-cell foam core are the primary composite system evaluated. Glass-fibre-reinforced polymer (GFRP) composite skins were also included for comparison in a comparable sandwich configuration. Full-scale blast experiments were conducted, where 1.6×1.3 m sized panels were subjected to blast of a Hopkinson–Cranz scaled distance of 3.02 m kg−1/3, 100 kg TNT equivalent at a stand-off distance of 14 m. This explosive blast represents a surface blast threat, where the shockwave propagates in air towards the naval vessel. Hopkinson was the first to investigate the characteristics of this explosive air-blast pulse (Hopkinson 1948 Proc. R. Soc. Lond. A 89, 411–413 (doi:10.1098/rspa.1914.0008)). Further analysis is provided on the performance of the CFRP sandwich panel relative to the GFRP sandwich panel when subjected to blast loading through use of high-speed speckle strain mapping. After the blast events, the residual compressive load-bearing capacity is investigated experimentally, using appropriate loading conditions that an in-service vessel may have to sustain. Residual strength testing is well established for post-impact ballistic assessment, but there has been less research performed on the residual strength of sandwich composites after blast. PMID:24711494

Credit PSR. This view depicts the southwest and southeast facades ...

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

Credit PSR. This view depicts the southwest and southeast facades as seen when looking west southwest (260°). The building consists of a small lean-to control room and a two-story space containing a large casting pit. The pit, which can be seen through the open doors, was never used due to changes in JPL's mission. This steel frame structure is clad in "Transite" board (a fire resistant pressed asbestos composite material) and interior lighting consists of individual explosion proof lamps mounted around the walls. The building was rated for 10,000 pounds (4,545 Kg) of class 2 materials and four personnel. It was licensed 5 June 1989 for ammonium perchlorate (NH4C10,), ammonium nitrate (NH4NO3), and sodium nitrate (NaNO3) - Jet Propulsion Laboratory Edwards Facility, Casting & Curing Building, Edwards Air Force Base, Boron, Kern County, CA

Experimental Study on Reaction Characteristics of PTFE/Ti/W Energetic Materials under Explosive Loading

PubMed Central

Li, Yan; Jiang, Chunlan; Wang, Zaicheng; Luo, Puguang

2016-01-01

Metal/fluoropolymer composites represent a new category of energetic structural materials that release energy through exothermic chemical reactions initiated under shock loading conditions. This paper describes an experiment designed to study the reaction characteristics of energetic materials with low porosity under explosive loading. Three PTFE (polytetrafluoroethylene)/Ti/W mixtures with different W contents are processed through pressing and sintering. An inert PTFE/W mixture without reactive Ti particles is also prepared to serve as a reference. Shock-induced chemical reactions are recorded by high-speed video through a narrow observation window. Related shock parameters are calculated based on experimental data, and differences in energy release are discussed. The results show that the reaction propagation of PTFE/Ti/W energetic materials with low porosity under explosive loading is not self-sustained. As propagation distance increases, the energy release gradually decreases. In addition, reaction failure distance in PTFE/Ti/W composites is inversely proportional to the W content. Porosity increased the failure distance due to higher shock temperature. PMID:28774056

Process for preparing energetic materials

DOEpatents

Simpson, Randall L [Livermore, CA; Lee, Ronald S [Livermore, CA; Tillotson, Thomas M [Tracy, CA; Hrubesh, Lawrence W [Pleasanton, CA; Swansiger, Rosalind W [Livermore, CA; Fox, Glenn A [Livermore, CA

2011-12-13

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

Sol-Gel Manufactured Energetic Materials

DOEpatents

Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

2005-05-17

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

Sol-gel manufactured energetic materials

DOEpatents

Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

2003-12-23

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

High temperature two component explosive

DOEpatents

Mars, James E.; Poole, Donald R.; Schmidt, Eckart W.; Wang, Charles

1981-01-01

A two component, high temperature, thermally stable explosive composition comprises a liquid or low melting oxidizer and a liquid or low melting organic fuel. The oxidizer and fuel in admixture are incapable of substantial spontaneous exothermic reaction at temperatures on the order of 475.degree. K. At temperatures on the order of 475.degree. K., the oxidizer and fuel in admixture have an activation energy of at least about 40 kcal/mol. As a result of the high activation energy, the preferred explosive compositions are nondetonable as solids at ambient temperature, and become detonable only when heated beyond the melting point. Preferable oxidizers are selected from alkali or alkaline earth metal nitrates, nitrites, perchlorates, and/or mixtures thereof. Preferred fuels are organic compounds having polar hydrophilic groups. The most preferred fuels are guanidinium nitrate, acetamide and mixtures of the two. Most preferred oxidizers are eutectic mixtures of lithium nitrate, potassium nitrate and sodium nitrate, of sodium nitrite, sodium nitrate and potassium nitrate, and of potassium nitrate, calcium nitrate and sodium nitrate.

Implications for Post-processing Nucleosynthesis of Core-collapse Supernova Models with Lagrangian Particles

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

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.

In this paper, we investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking onlymore » $$(\\alpha ,\\gamma )$$ reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles; inconsistent thermodynamic evolution, including misestimation of expansion timescales; and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. Finally, we present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 $${M}_{\\odot }$$ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.« less

Implications for Post-processing Nucleosynthesis of Core-collapse Supernova Models with Lagrangian Particles

NASA Astrophysics Data System (ADS)

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.; Lee, C. T.; Lentz, Eric J.; Messer, O. E. Bronson

2017-07-01

We investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking only (α ,γ ) reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles inconsistent thermodynamic evolution, including misestimation of expansion timescales and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. We present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 {M}⊙ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.

Implications for Post-processing Nucleosynthesis of Core-collapse Supernova Models with Lagrangian Particles

DOE PAGES

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.; ...

2017-06-26

In this paper, we investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking onlymore » $$(\\alpha ,\\gamma )$$ reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles; inconsistent thermodynamic evolution, including misestimation of expansion timescales; and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. Finally, we present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 $${M}_{\\odot }$$ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.« less

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.

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.

Comparison of ground motion from tremors and explosions in deep gold mines

USGS Publications Warehouse

McGarr, A.; Bicknell, J.; Churcher, J.; Spottiswoode, S.

1990-01-01

Seismic body waves, from tamped chemical explosions, two with yields of 50 and one of 150 kg, were compared with corresponding data from three mining-induced tremors with a view to testing methods of discriminating between the two types of events. It is concluded that for events of fixed low-frequency spectral asymptotes, the explosions typically have higher corner frequencies than tremors or earthquakes, although counterexamples certainly exist. Interestingly, the 150-kg explosion was identified as such on the basis of P and S wave polarities that are incompatible with the normally expected double-couple source model; instead these initial motions are consistent with an explosion in conjunction with normal faulting. The body wave spectra of this explosion and those of a nearby tremor, however, were indistinguishable. -from Authors

Thermally generated magnetic fields in laser-driven compressions and explosions

NASA Technical Reports Server (NTRS)

Tidman, D. A.

1975-01-01

The evolution of thermally generated magnetic fields in a plasma undergoing a nearly spherically symmetric adiabatic compression or expansion is calculated. The analysis is applied to obtain approximate results for the development of magnetic fields in laser-driven compression and explosion of a pellet of nuclear fuel. Localized sources, such as those occurring at composition boundaries in structured pellets or at shock fronts, give stronger fields than those deriving from smoothly distributed asymmetries. Although these fields may approach 10 million G in the late stages of compression, this is not expected to present difficulties for the compression process. Assuming ignition of a nuclear explosion occurs, the sources become much stronger, and values of approximately 10 billion G are obtained at tamper boundaries assuming a 20% departure from spherical symmetry during the explosion.

Phase Structures and Magnetic Properties of Graphite Nanosheets and Ni-Graphite Nanocomposite Synthesized by Electrical Explosion of Wire in Liquid

NASA Astrophysics Data System (ADS)

Nguyen, Minh-Thuyet; Kim, Jin-Hyung; Lee, Jung-Goo; Kim, Jin-Chun

2018-03-01

The present work studied on phases and magnetic properties of graphite nanosheets and Ni-graphite nanocomposite synthesized using the electrical explosion of wire (EEW) in ethanol. X-ray diffraction and field emission scanning electron microscope were used to investigate the phases and the morphology of the nanopowders obtained. It was found that graphite nanosheets were absolutely fabricated by EEW with a thickness of 29 nm and 3 μm diameter. The as-synthesized Ni-graphite composite powders had a Ni-coating on the surfaces of graphite sheets. The hysteresis loop of the as-exploded, the hydrogen-treated composite nanopowders and the sintered samples were examined with a vibrating sample magnetometer at room temperature. The Ni-graphite composite exposed the magnetic behaviors which are attributed to Ni component. The magnetic properties of composite had the improvement from 10.2 emu/g for the as-exploded powders to 15.8 emu/g for heat-treated powders and 49.16 emu/g for sintered samples.

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

DOE PAGES

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

2017-08-25

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

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

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements.

PubMed

Bonamici, Chloë E; Hervig, Richard L; Kinman, William S

2017-09-19

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. Using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclides generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Furthermore, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.

Nucleosynthesis in Primordial Hypernovae

NASA Astrophysics Data System (ADS)

Grimmett, J. J.; Heger, Alexander; Karakas, Amanda I.; Müller, Bernhard

2018-06-01

We investigate the relationship between explosion energy and nucleosynthesis in Population III supernovae and provide nucleosynthetic results for the explosions of stars with progenitor masses of 15 M⊙, 20 M⊙, 30 M⊙, 40 M⊙, 60 M⊙, and 80 M⊙, and explosion energies between approximately 1050 erg and 1053 erg. We find that the typical abundance pattern observed in metal-poor stars are best matched by supernovae with progenitor mass in the range 15 M⊙ - 30 M⊙, and explosion energy of ˜(5 - 10) × 1051 erg. In these models, a reverse shock caused by jumps in density between shells of different composition serves to decrease synthesis of chromium and manganese, which is favourable to matching the observed abundances in metal-poor stars. Spherically symmetric explosions of our models with progenitor mass ≥40 M⊙ do not provide yields that are compatible with the iron-peak abundances that are typically observed in metal-poor stars, however, by approximating the yields that we might expect from these models in highly aspherical explosions, we find indications that explosions of stars 40 M⊙ - 80 M⊙ with bipolar jets may be good candidates for the enrichment sources of metal-poor stars with enhanced carbon abundances.

Nucleosynthesis in Thermonuclear Supernovae

NASA Astrophysics Data System (ADS)

Seitenzahl, Ivo Rolf; Townsley, Dean M.

The explosion energy of thermonuclear (type Ia) supernovae is derived from the difference in nuclear binding energy liberated in the explosive fusion of light "fuel" nuclei, predominantly carbon and oxygen, into more tightly bound nuclear "ash" dominated by iron and silicon group elements. The very same explosive thermonuclear fusion event is also one of the major processes contributing to the nucleosynthesis of the heavy elements, in particular the iron-group elements. For example, most of the iron and manganese in the sun and its planetary system were produced in thermonuclear supernovae. Here, we review the physics of explosive thermonuclear burning in carbon-oxygen white dwarf material and the methodologies utilized in calculating predicted nucleosynthesis from hydrodynamic explosion models. While the dominant explosion scenario remains unclear, many aspects of the nuclear combustion and nucleosynthesis are common to all models and must occur in some form in order to produce the observed yields. We summarize the predicted nucleosynthetic yields for existing explosion models, placing particular emphasis on characteristic differences in the nucleosynthetic signatures of the different suggested scenarios leading to type Ia supernovae. Following this, we discuss how these signatures compare with observations of several individual supernovae, remnants, and the composition of material in our galaxy and galaxy clusters.

Direct Real-Time Detection of Vapors from Explosive Compounds

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

Ewing, Robert G.; Clowers, Brian H.; Atkinson, David A.

2013-10-03

The real-time detection of vapors from low volatility explosives including PETN, tetryl, RDX and nitroglycerine along with various compositions containing these substances is demonstrated. This was accomplished with an atmospheric flow tube (AFT) using a non-radioactive ionization source and coupled to a mass spectrometer. Direct vapor detection was demonstrated in less than 5 seconds at ambient temperature without sample pre-concentration. The several seconds of residence time of analytes in the AFT provides a significant opportunity for reactant ions to interact with analyte vapors to achieve ionization. This extended reaction time, combined with the selective ionization using the nitrate reactant ionsmore » (NO3- and NO3-•HNO3), enables highly sensitive explosives detection. Observed signals from diluted explosive vapors indicate detection limits below 10 ppqv using selected ion monitoring (SIM) of the explosive-nitrate adduct at m/z 349, 378, 284 and 289 for tetryl, PETN, RDX and NG respectively. Also provided is a demonstration of the vapor detection from 10 different energetic formulations, including double base propellants, plastic explosives and commercial blasting explosives using SIM for the NG, PETN and RDX product ions.« less

Broadband Evaluation of DPRK Explosions, Collapse Event, and Induced Aftershocks

NASA Astrophysics Data System (ADS)

Mayeda, K.; Roman-Nieves, J. I.; Wagner, G.; Jeon, Y. S.

2017-12-01

We report on the past 6 declared DPRK nuclear explosions, a collapse event, and recent associated induced shear dislocation sources using long-period waveform modeling, direct regional phases, and stable P-coda and S-coda spectral ratios. We find that the recent September 3rd, 2017 explosion is well modeled with an MM71 explosion source model at normal scale depth, but the previous 5 smaller yield explosions exhibit much larger relative high frequency radiation, strongly suggesting they are all over buried by varying amounts. The collapse event that occurred 8 minutes following the September 3rd DPRK explosion shares significant similarities with a number of NTS collapse events for explosions of comparable yield, both in absolute amplitude and spectral fall-off. A large number of smaller sources have been observed, which from stable coda spectral analysis and waveform modeling, are consistent with shallow shear dislocations likely caused by stress redistribution following the past nuclear explosions. We conclude with testing of a new discriminant that is specific to this region.

The Plumbing System of a Highly Explosive Basaltic Volcano: Sunset Crater, AZ

NASA Astrophysics Data System (ADS)

Allison, C. M.; Roggensack, K.; Clarke, A. B.

2015-12-01

We seek to better understand highly explosive basaltic eruptions with specific focus on magmatic volatile solubility in alkali basalts and the magma plumbing system. Sunset Crater, an alkali basalt (~3.7 wt.% alkalis) scoria cone volcano, erupted explosively in 1085 AD. We analyzed 125 primary melt inclusions (MIs) from Sunset Crater tephra deposited by 2 subplinian phases and 1 Strombolian explosion to compare magma volatiles and storage conditions. We picked rapidly quenched free olivine crystals and selected large volume MIs (50-180 μm) located toward crystal cores. MIs are faceted and exhibit little major element composition variability with minor post entrapment crystallization (2-10%). MIs are relatively dry but CO2-rich. Water content varies from 0.4 wt.% to 1.5 wt.% while carbon dioxide abundance ranges between 1,150 ppm and 3,250 ppm. Most MIs contain >1 wt.% H2O and >2,150 ppm CO2. All observed MIs contain a vapor bubble, so we are evaluating MI vapor bubbles with Raman spectroscopy and re-homogenization experiments to determine the full volatile budget. Because knowledge of volatile solubility is critical to accurately interpret results from MI analyses, we measured H2O-CO2 solubility in the Sunset Crater bulk composition. Fluid-saturated experiments at 4 and 6 kbar indicate shallower entrapment pressures for these MIs than values calculated for this composition using existing models. Assuming fluid saturation, MIs record depths from 6 km to 14 km, including groupings suggesting two pauses for longer-term storage at ~6 km and ~10.5 km. We do not observe any significant differences in MIs from phases exhibiting different eruptive styles, suggesting that while a high CO2 content may drive rapid magma ascent and be partly responsible for highly explosive eruptions, shallower processes may govern the final eruptive character. To track shallow processes during magma ascent from depth of MI-entrapment up to the surface, we are examining MI re-entrants.

49 CFR 173.59 - Description of terms for explosives.

Code of Federal Regulations, 2012 CFR

2012-10-01

... perforating guns, charged, oil well, without detonator. Articles consisting of a steel tube or metallic strip... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS... fiber, metal or other material containing only propellant explosive. The term excludes charges, shaped...

Analysis of microstructure-dependent shock dissipation and hot-spot formation in granular metalized explosive

NASA Astrophysics Data System (ADS)

Chakravarthy, Sunada; Gonthier, Keith A.

2016-07-01

Variations in the microstructure of granular explosives (i.e., particle packing density, size, shape, and composition) can affect their shock sensitivity by altering thermomechanical fields at the particle-scale during pore collapse within shocks. If the deformation rate is fast, hot-spots can form, ignite, and interact, resulting in burn at the macro-scale. In this study, a two-dimensional finite and discrete element technique is used to simulate and examine shock-induced dissipation and hot-spot formation within low density explosives (68%-84% theoretical maximum density (TMD)) consisting of large ensembles of HMX (C4H8N8O8) and aluminum (Al) particles (size ˜ 60 -360 μm). Emphasis is placed on identifying how the inclusion of Al influences effective shock dissipation and hot-spot fields relative to equivalent ensembles of neat/pure HMX for shocks that are sufficiently strong to eliminate porosity. Spatially distributed hot-spot fields are characterized by their number density and area fraction enabling their dynamics to be described in terms of nucleation, growth, and agglomeration-dominated phases with increasing shock strength. For fixed shock particle speed, predictions indicate that decreasing packing density enhances shock dissipation and hot-spot formation, and that the inclusion of Al increases dissipation relative to neat HMX by pressure enhanced compaction resulting in fewer but larger HMX hot-spots. Ensembles having bimodal particle sizes are shown to significantly affect hot-spot dynamics by altering the spatial distribution of hot-spots behind shocks.

Evolution of Carbon Clusters in the Detonation Products of the Triaminotrinitrobenzene (TATB)-Based Explosive PBX 9502

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

Watkins, Erik B.; Velizhanin, Kirill A.; Dattelbaum, Dana M.

Here, the detonation of carbon-rich high explosives yields solid carbon as a major constituent of the product mixture and, depending on the thermodynamic conditions behind the shock front, a variety of carbon allotropes and morphologies may form and evolve. We applied time-resolved small angle x-ray scattering (TR-SAXS) to investigate the dynamics of carbon clustering during detonation of PBX 9502, an explosive composed of triaminotrinitrobenzene (TATB) and 5 wt% fluoropolymer binder. Solid carbon formation was probed from 0.1 to 2.0 μs behind the detonation front and revealed rapid carbon cluster growth which reached a maximum after ~200 ns. The late-time carbonmore » clusters had a radius of gyration of 3.3 nm which is consistent with 8.4 nm diameter spherical particles and matched particle sizes of recovered products. Simulations using a clustering kinetics model were found to be in good agreement with the experimental measurements of cluster growth when invoking a freeze-out temperature, and temporal shift associated with the initial precipitation of solid carbon. Product densities from reactive flow models were compared to the electron density contrast obtained from TR-SAXS and used to approximate the carbon cluster composition as a mixture of 20% highly ordered (diamond-like) and 80% disordered carbon forms, which will inform future product equation of state models for solid carbon in PBX 9502 detonation product mixtures.« less

Evolution of Carbon Clusters in the Detonation Products of the Triaminotrinitrobenzene (TATB)-Based Explosive PBX 9502

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

Watkins, Erik B.; Velizhanin, Kirill A.; Dattelbaum, Dana M.

The detonation of carbon-rich high explosives yields solid carbon as a major constituent of the product mixture and, depending on the thermodynamic conditions behind the shock front, a variety of carbon allotropes and morphologies may form and evolve. We applied time-resolved small angle x-ray scattering (TR-SAXS) to investigate the dynamics of carbon clustering during detonation of PBX 9502, an explosive composed of triaminotrinitrobenzene (TATB) and 5 wt% fluoropolymer binder. Solid carbon formation was probed from 0.1 to 2.0 μs behind the detonation front and revealed rapid carbon cluster growth which reached a maximum after ~200 ns. The late-time carbon clustersmore » had a radius of gyration of 3.3 nm which is consistent with 8.4 nm diameter spherical particles and matched particle sizes of recovered products. Simulations using a clustering kinetics model were found to be in good agreement with the experimental measurements of cluster growth when invoking a freeze-out temperature, and temporal shift associated with the initial precipitation of solid carbon. Product densities from reactive flow models were compared to the electron density contrast obtained from TR-SAXS and used to approximate the carbon cluster composition as a mixture of 20% highly ordered (diamond-like) and 80% disordered carbon forms, which will inform future product equation of state models for solid carbon in PBX 9502 detonation product mixtures.« less

Evolution of Carbon Clusters in the Detonation Products of the Triaminotrinitrobenzene (TATB)-Based Explosive PBX 9502

DOE PAGES

Watkins, Erik B.; Velizhanin, Kirill A.; Dattelbaum, Dana M.; ...

2017-08-15

Here, the detonation of carbon-rich high explosives yields solid carbon as a major constituent of the product mixture and, depending on the thermodynamic conditions behind the shock front, a variety of carbon allotropes and morphologies may form and evolve. We applied time-resolved small angle x-ray scattering (TR-SAXS) to investigate the dynamics of carbon clustering during detonation of PBX 9502, an explosive composed of triaminotrinitrobenzene (TATB) and 5 wt% fluoropolymer binder. Solid carbon formation was probed from 0.1 to 2.0 μs behind the detonation front and revealed rapid carbon cluster growth which reached a maximum after ~200 ns. The late-time carbonmore » clusters had a radius of gyration of 3.3 nm which is consistent with 8.4 nm diameter spherical particles and matched particle sizes of recovered products. Simulations using a clustering kinetics model were found to be in good agreement with the experimental measurements of cluster growth when invoking a freeze-out temperature, and temporal shift associated with the initial precipitation of solid carbon. Product densities from reactive flow models were compared to the electron density contrast obtained from TR-SAXS and used to approximate the carbon cluster composition as a mixture of 20% highly ordered (diamond-like) and 80% disordered carbon forms, which will inform future product equation of state models for solid carbon in PBX 9502 detonation product mixtures.« less

Plywood production wastes to energy

NASA Astrophysics Data System (ADS)

Lyubov, V. K.; Popov, A. N.

2017-11-01

Wood and by-products of its processing are a renewable energy source with carbon neutral and may be used in solving energy problems. ZAO «Arkhangelsk plywood factory» installed and put into operation the boiler with capacity of 22 MW (saturated steam of 1.2 MPa) to reduce the cost of thermal energy, the impact of environmental factors on stability of the company’s development and for reduction of harmful emissions into the environment. Fuel for boiler is the mixture consists of chip plywood, birch bark, wood sanding dust (WSD) and sawdust of the plywood processing. The components of the fuel mixture significantly differ in thermotechnical characteristics and technological parameters but especially in size composition. Particle dimensions in the fuel mixture differ by more than a thousand times which makes it «unique» and very difficult to ensure the effective and non-explosive use. WSD and sawdust from line of cutting of plywood are small fraction material and relate to IV group of explosion. Criterion of explosive for them has great values (КfWSD=10.85 Кfsaw=9.66). Boiler’s furnace equipped with reciprocating grate where implemented a three-stage scheme of combustion. For a comprehensive survey of the effectiveness of installed equipment was analyzed the design features of the boiler, defined the components of thermal balance, studied nitrogen oxide emissions, carbon and particulate matter with the determination of soot emissions. Amount of solid particles depending on their shape and size was analyzed.

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.

A review of Explosives Used in Explosive Excavation Research Laboratory Projects Since 1969

DTIC Science & Technology

1974-12-01

Boron compounds Potassium dichramat« Antimony compounds Bismuth compounds P«riodat«s Litharge Guar gum (polysaccSarid«) Storch Acrylomid... gum , and gelled with a cross- linking agent. The i-arliest slurries used Government surplus TNT as a fuel-sensitizer, but the majority o...Nonexplosive TNT PETN RDX Rentalite Composition B Guanidine nitrate Smokeless powder Nitres*: ch Alky’amine nitrates Nit.omannite Aluminum Sugar

Army Research Laboratory 2009 Annual Review

DTIC Science & Technology

2009-01-01

and in new Navy DDX and DDG ships . As a result of the high performance and low weight of composite materials, it is very likely that the Services...labs, an explosives casting lab, and it also has explosives x-ray capability . An indoor small arms shooting performance simulator with a high ...of nervous systems, rather than simply depending upon the adaptive abilities of Soldiers, and radically improve Soldier-system performance . a high

Short Term Innovative Research Program: Nanoengineered Reactive Materials for Tunable Ignition and Energy Release

DTIC Science & Technology

2009-01-01

Background Most conventional explosives can be roughly categorized into two classes – molecular materials and intermolecular composites. Molecular...materials refer to species such as the nitroalkanes (e.g. nitromethane ) and cyclic nitramines (e.g. TNAZ, RDX, HMX) that release chemical energy...alternative to conventional explosives that has been gaining increasing interest have been termed reactive materials, and are defined as systems in

Bomb Detection System Study

DTIC Science & Technology

1965-01-01

cause the reduction in vapor pressure. To determine whether an explosive can be detected thi ugh its * vapor, it is necessary to know the vapor pressures...Smokeless powders are explosives normally used in shotgun powders and can vary widely in composition. Nitrocellulose is the major :oomponent. Dinitrotoluene...will not be inclined to undertake the risky process except under very unusual circum- stances. Black powder is an obvious choice and has been so in

Gas chromatographic detection of some nitro explosive compounds in soil samples after solid-phase microextraction with carbon ceramic copper nanoparticle fibers.

PubMed

Farhadi, Khalil; Bochani, Shayesteh; Hatami, Mehdi; Molaei, Rahim; Pirkharrati, Hossein

2014-07-01

In this research, a new solid-phase microextraction fiber based on carbon ceramic composites with copper nanoparticles followed by gas chromatography with flame ionization detection was applied for the extraction and determination of some nitro explosive compounds in soil samples. The proposed method provides an overview of trends related to synthesis of solid-phase microextraction sorbents and their applications in preconcentration and determination of nitro explosives. The sorbents were prepared by mixing of copper nanoparticles with a ceramic composite produced by mixture of methyltrimethoxysilane, graphite, methanol, and hydrochloric acid. The prepared sorbents were coated on copper wires by dip-coating method. The prepared nanocomposites were evaluated statistically and provided better limits of detection than the pure carbon ceramic. The limit of detection of the proposed method was 0.6 μg/g with a linear response over the concentration range of 2-160 μg/g and square of correlation coefficient >0.992. The new proposed fiber has been demonstrated to be a suitable, inexpensive, and sensitive candidate for extraction of nitro explosive compounds in contaminated soil samples. The constructed fiber can be used more than 100 times without the need for surface generation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantitative analysis for the determination of aluminum percentage and detonation performance of aluminized plastic bonded explosives by laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Rezaei, A. H.; Keshavarz, M. H.; Kavosh Tehrani, M.; Darbani, S. M. R.

2018-06-01

The aluminized plastic-bonded explosive (PBX) is a composite material in which solid explosive particles are dispersed in a polymer matrix, which includes three major components, i.e. polymeric binder, metal fuel (aluminum) and nitramine explosive. This work introduces a new method on the basis of the laser-induced breakdown spectroscopy (LIBS) technique in air and argon atmospheres to investigate the determination of aluminum content and detonation performance of aluminized PBXs. Plasma emissions of aluminized PBXs are recorded where atomic lines of Al, C and H as well as molecular bands of AlO and CN are identified. The experimental results demonstrate that a good discrimination and separation between the aluminized PBXs is possible using LIBS and principle component analysis, although they have similar atomic composition. Relative intensity of the AlO/Al is used to determine aluminum percentage of the aluminized PBXs. The obtained quantitative calibration curve using the relative intensity of the AlO/Al is better than the resulting calibration curve using only the intensity of Al. By using the LIBS method and the measured intensity ratio of CN/C, an Al content of 15% is found to be the optimum value in terms of velocity of detonation of the RDX/Al/HTPB standard samples.

Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

PubMed

Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

2011-06-15

The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour. Copyright © 2011 Elsevier B.V. All rights reserved.

Innovative Composite Structure Design for Blast Protection

DTIC Science & Technology

2007-01-01

2007-01-0483 Innovative Composite Structure Design for Blast Protection Dongying Jiang, Yuanyuan Liu MKP Structural Design Associates, Inc...protect vehicle and occupants against various explosives. The multi-level and multi-scenario blast simulation and design system integrates three major...numerical simulation of a BTR composite under a blast event. The developed blast simulation and design system will enable the prediction, design, and

Explosive volcanism may not be an inevitable consequence of magma fragmentation.

PubMed

Gonnermann, Helge M; Manga, Michael

2003-11-27

The fragmentation of magma, containing abundant gas bubbles, is thought to be the defining characteristic of explosive eruptions. When viscous stresses associated with the growth of bubbles and the flow of the ascending magma exceed the strength of the melt, the magma breaks into disconnected fragments suspended within an expanding gas phase. Although repeated effusive and explosive eruptions for individual volcanoes are common, the dynamics governing the transition between explosive and effusive eruptions remain unclear. Magmas for both types of eruptions originate from sources with similar volatile content, yet effusive lavas erupt considerably more degassed than their explosive counterparts. One mechanism for degassing during magma ascent, consistent with observations, is the generation of intermittent permeable fracture networks generated by non-explosive fragmentation near the conduit walls. Here we show that such fragmentation can occur by viscous shear in both effusive and explosive eruptions. Moreover, we suggest that such fragmentation may be important for magma degassing and the inhibition of explosive behaviour. This implies that, contrary to conventional views, explosive volcanism is not an inevitable consequence of magma fragmentation.

Double-pulse standoff laser-induced breakdown spectroscopy for versatile hazardous materials detection

NASA Astrophysics Data System (ADS)

Gottfried, Jennifer L.; De Lucia, Frank C.; Munson, Chase A.; Miziolek, Andrzej W.

2007-12-01

We have developed a double-pulse standoff laser-induced breakdown spectroscopy (ST-LIBS) system capable of detecting a variety of hazardous materials at tens of meters. The use of a double-pulse laser improves the sensitivity and selectivity of ST-LIBS, especially for the detection of energetic materials. In addition to various metallic and plastic materials, the system has been used to detect bulk explosives RDX and Composition-B, explosive residues, biological species such as the anthrax surrogate Bacillus subtilis, and chemical warfare simulants at 20 m. We have also demonstrated the discrimination of explosive residues from various interferents on an aluminum substrate.

Eruption style at Kīlauea Volcano in Hawai‘i linked to primary melt composition

USGS Publications Warehouse

Sides. I.R.,; Edmonds, M.; Maclennan, J.; Swanson, Don; Houghton, Bruce F.

2014-01-01

Explosive eruptions at basaltic volcanoes have been linked to gas segregation from magmas at shallow depths in the crust. The composition of primary melts formed at greater depths was thought to have little influence on eruptive style. Ocean island basaltic volcanoes are the product of melting of a geochemically heterogeneous mantle plume and are expected to give rise to heterogeneous primary melts. This range in primary melt composition, particularly with respect to the volatile components, will profoundly influence magma buoyancy, storage and eruption style. Here we analyse the geochemistry of a suite of melt inclusions from 25 historical eruptions at the ocean island volcano of Kīlauea, Hawai‘i, over the past 600 years. We find that more explosive styles of eruption at Kīlauea Volcano are associated statistically with more geochemically enriched primary melts that have higher volatile concentrations. These enriched melts ascend faster and retain their primary nature, undergoing little interaction with the magma reservoir at the volcano’s summit. We conclude that the eruption style and magma-supply rate at Kīlauea are fundamentally linked to the geochemistry of the primary melts formed deep below the volcano. Magmas might therefore be predisposed towards explosivity right at the point of formation in their mantle source region.

Evaluation of Various Organic Fertilizer Substrates and Hydraulic Retention Times for Enhancing Anaerobic Degradation of Explosives-Contaminated Groundwater While Using Constructed Wetlands at the Milan Army Ammunition Plant, Milan, Tennessee.

DTIC Science & Technology

1998-05-01

CODES FIELD GROUP SUB-GROUP 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) Phytoremediation of Explosives... phytoremediating explosives-contaminated groundwater. A typical gravel-based wetland consists of an anaerobic cell for removing the bulk of the explosive...11 4-1 4-1 4-3 Phytoremediation Study Milan AAP SECTION TABLE OF CONTENTS (Continued) TITLE PAGE 4.0 4.3 4.4 4.5 5.0 6.0 RESULTS AND

Dance of the Light Echoes

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for larger poster version

This composite image from NASA's Spitzer Space Telescope shows the remnant of a star that exploded, called Cassiopeia A (center) and its surrounding 'light echoes' -- dances of light through dusty clouds, created when stars blast apart. The light echoes are colored and the surrounding clouds of dust are gray.

In figure 1, dramatic changes are highlighted in phenomena referred to as light echoes (colored areas) around the Cassiopeia A supernova remnant (center). Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died.

A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light. In figure 1, this apparent motion can be seen here by the shift in colored dust clumps

Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died. This remnant is located 11,000 light-years away in the northern constellation Cassiopeia.

This composite consists of six processed images taken over a time span of three years. Dust features that have not changed over time appear gray, while those that have changed are colored blue or orange. Bluer colors represent an earlier time and redder ones, a later time. The progression of the light echo through the dust can be seen here by the shift in colored dust clumps.

This light echo is the largest ever seen, stretching more than 300 light-years away from Cassiopeia A. If viewed from Earth, the entire frame would take up the same amount of space as seven full moons. The supernova remnant is located 11,000 light-years away in the northern constellation Cassiopeia.

The earliest Spitzer image shown here was taken in February 2005, and the latest one in January 2008. The image was processed to emphasize the light echo by enhancing the areas that change, which appear in color, and dimming regions that remain constant, seen in grayscale. Spurious color artifacts such as diffraction spikes around stars were removed by hand.

Multilevel composition fractionation process for high-value utilization of wheat straw cellulose.

PubMed

Chen, Hong-Zhang; Liu, Zhi-Hua

2014-01-01

Biomass refining into multiple products has gained considerable momentum due to its potential benefits for economic and environmental sustainability. However, the recalcitrance of biomass is a major challenge in bio-based product production. Multilevel composition fractionation processes should be beneficial in overcoming biomass recalcitrance and achieving effective conversion of multiple compositions of biomass. The present study concerns the fractionation of wheat straw using steam explosion, coupled with ethanol extraction, and that this facilitates the establishment of sugars and lignin platform and enables the production of regenerated cellulose films. The results showed that the hemicellulose fractionation yield was 73% under steam explosion at 1.6 MPa for 5.2 minutes, while the lignin fractionation yield was 90% by ethanol extraction at 160°C for 2 hours and with 60% ethanol (v/v). The cellulose yield reached up to 93% after steam explosion coupled with ethanol extraction. Therefore, cellulose sugar, hemicellulose sugar, and lignin platform were established effectively in the present study. Long fibers (retained by a 40-mesh screening) accounted for 90% of the total cellulose fibers, and the glucan conversion of short fibers was 90% at 9.0 hours with a cellulase loading of 25 filter paper units/g cellulose in enzymatic hydrolysis. Regenerated cellulose film was prepared from long fibers using [bmim]Cl, and the tensile strength and breaking elongation was 120 MPa and 4.8%, respectively. The cross-section of regenerated cellulose film prepared by [bmim]Cl displayed homogeneous structure, which indicated a dense architecture and a better mechanical performance. Multilevel composition fractionation process using steam explosion followed by ethanol extraction was shown to be an effective process by which wheat straw could be fractionated into different polymeric fractions with high yields. High-value utilization of wheat straw cellulose was achieved by preparing regenerated cellulose film using [bmim]Cl.

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.

Understanding and Predicting the Thermal Explosion Violence of HMX-Based and RDX-Based Explosives - Experimental Measurements of Material Properties and Reaction Violence

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

Maienschein, J L; Wardell, J F; Weese, R K

The violence of thermal explosions with energetic materials is affected by many material properties, including mechanical and thermal properties, thermal ignition kinetics, and deflagration behavior. These properties must be characterized for heated samples as well as pristine materials. We present available data for these properties for two HMX-based formulations--LX-04 and PBX-9501, and two RDX-based formulations--Composition B and PBXN-109. We draw upon separately published data on the thermal explosion violence with these materials to compare the material properties with the observed violence. We have the most extensive data on deflagration behavior of these four formulations, and we discuss the correlation ofmore » the deflagration data with the violence results. The data reported here may also be used to develop models for application in simulation codes such as ALE3D to calculate and Dredict thermal explosion violence.« less

Association of School Environment and After-School Physical Activity with Health-Related Physical Fitness among Junior High School Students in Taiwan

PubMed Central

Lo, Kai-Yang; Wu, Min-Chen; Tung, Shu-Chin; Hsieh, City C.; Yao, Hsueh-Hua; Ho, Chien-Chang

2017-01-01

The relationship between students’ school environment and exercise habits is complex, and is affected by numerous factors. However, the few studies that have been conducted on this relationship have reported inconsistent results, especially regarding Taiwanese students. We conducted this cross-sectional study to investigate the association of school environment and after-school physical activity with health-related physical fitness in Taiwanese adolescents. Data were drawn from a national survey conducted by the Ministry of Education in Taiwan in 2008 of health-related physical fitness measurements among junior high school students (649,442 total) in grades seven to nine. School environment (level of urbanization, school size, presence of sports field or gymnasium) and after-school physical activity were assessed for their association with adolescents’ physical fitness measurements (body mass index (BMI), bent-leg sit-ups, 800-/1600-m run, sit-and-reach, standing long jump). Urban boys and girls perform significantly better in muscle strength and endurance, cardiorespiratory endurance, flexibility, and explosive power; girls from rural areas exhibited significantly worse scores in body composition. Boys from large-size schools performed the worst in cardiorespiratory endurance, flexibility, and explosive power; whereas girls from large-size schools performed the worst in muscle strength, muscle endurance, and explosive power, but had the best score for body composition. However, the differences in body composition of boys from large-, medium-, and small- size schools did not reach a statistically significant level. Adolescents of both genders in schools with a sports field or gymnasium exhibited significantly better in muscle strength and endurance, cardiorespiratory endurance, and explosive power. Boys in schools with a sports field or gymnasium had significantly better body composition; girls in schools with sports field or gymnasium differed significantly in flexibility. Adolescents of both genders who participated in physical activity after school had significantly better body composition, cardiorespiratory endurance, and flexibility. Boys who participated in physical activity after school significantly differed in explosive power, whereas girls who participated in physical activity after school exhibited significantly better flexibility. Thus, the current study demonstrated that some factors, including urbanization (school location in rural or urban areas), school size, school facility provision (school with or without sports fields or gymnasiums), and after-school physical activity participation are more important than others in shaping adolescents’ physical fitness in Taiwan; meanwhile, these association patterns differed by gender. PMID:28098836

Association of School Environment and After-School Physical Activity with Health-Related Physical Fitness among Junior High School Students in Taiwan.

PubMed

Lo, Kai-Yang; Wu, Min-Chen; Tung, Shu-Chin; Hsieh, City C; Yao, Hsueh-Hua; Ho, Chien-Chang

2017-01-15

The relationship between students' school environment and exercise habits is complex, and is affected by numerous factors. However, the few studies that have been conducted on this relationship have reported inconsistent results, especially regarding Taiwanese students. We conducted this cross-sectional study to investigate the association of school environment and after-school physical activity with health-related physical fitness in Taiwanese adolescents. Data were drawn from a national survey conducted by the Ministry of Education in Taiwan in 2008 of health-related physical fitness measurements among junior high school students (649,442 total) in grades seven to nine.School environment (level of urbanization, school size, presence of sports field or gymnasium) and after-school physical activity were assessed for their association with adolescents' physical fitness measurements (body mass index (BMI), bent-leg sit-ups, 800-/1600-m run, sit-and-reach, standing long jump). Urban boys and girls perform significantly better in muscle strength and endurance, cardiorespiratory endurance, flexibility, and explosive power; girls from rural areas exhibited significantly worse scores in body composition. Boys from large-size schools performed the worst in cardiorespiratory endurance, flexibility, and explosive power; whereas girls from large-size schools performed the worst in muscle strength, muscle endurance, and explosive power, but had the best score for body composition. However, the differences in body composition of boys from large-, medium-, and small- size schools did not reach a statistically significant level. Adolescents of both genders in schools with a sports field or gymnasium exhibited significantly better in muscle strength and endurance, cardiorespiratory endurance, and explosive power. Boys in schools with a sports field or gymnasium had significantly better body composition; girls in schools with sports field or gymnasium differed significantly in flexibility. Adolescents of both genders who participated in physical activity after school had significantly better body composition, cardiorespiratory endurance, and flexibility. Boys who participated in physical activity after school significantly differed in explosive power, whereas girls who participated in physical activity after school exhibited significantly better flexibility. Thus, the current study demonstrated that some factors, including urbanization (school location in rural or urban areas), school size, school facility provision (school with or without sports fields or gymnasiums), and after-school physical activity participation are more important than others in shaping adolescents' physical fitness in Taiwan; meanwhile, these association patterns differed by gender.

Novel concept of recycling sludge and dust to BOF converter through dispersed in-situ phase induced by composite ball explosive reaction

NASA Astrophysics Data System (ADS)

Tang, Fu-ping; Yu, Shu-juan; Fei, Peng; Hou, Hou-yu; Qian, Feng; Wang, Xiao-feng

2017-08-01

Recycling of iron and steelmaking dusts is a key issue in environmental protection efforts and to ensure efficient utilization. In this investigation, we developed a novel recovery process that uses a dispersed in-situ phase induced by an explosive reaction of composite balls of iron and steelmaking dusts. We designed and prepared composite balls for this function using a laboratory model batch-type balling disc (at 12 r/min) and optimized the feeding modes in 180-t and 260-t basic oxygen furnace (BOF) converters. The results indicate that feeding composite balls into BOF converters is an effective novel technology for recovering iron and steelmaking dusts. The period after hot metal charging and prior to the oxygen-blowing process is the most reasonable time to feed composite balls. Composite ball treatment is not appropriate for steel production with sulfur requirements lower than 80 ppm. The maximum composite ball feeding amount is 40 kg/t and the iron yield rate is better than 95%. Compared with the conventional recycling process of sludge and dust, this novel technology is more convenient and efficient, saving up to 309 RMB per ton of steel. Further investigation of this novel recycling technology is merited.

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.

49 CFR 173.59 - Description of terms for explosives.

Code of Federal Regulations, 2010 CFR

2010-10-01

... consisting of all types of bombs, grenades, rockets, mines, projectiles and other similar devices or... illuminating cartridges, grenades and projectiles, and illuminating and target identification bombs. The term... nitrate, and sulphur. It may be meal, granular, compressed, or pelletized. Bombs. Explosive articles which...

Broadband measurements of the sources of explosions at Stromboli Volcano, Italy

USGS Publications Warehouse

Chouet, B.; Saccorotti, G.; Dawson, P.; Martini, M.; Scarpa, R.; De Luca, G.; Milana, G.; Cattaneo, M.

1999-01-01

During September-October 1997, 21 three-component broadband seismometers were deployed on Stromboli Volcano at radial distances of 0.3-2.2 km from the active crater to investigate the source mechanisms of Strombolian explosions. In the 2-50 s band, the very-long period (VLP) signals associated with explosions are consistent with two stationary sources repeatedly activated in time. VLP particle motions are essentially linear and analyses of semblance and particle motions are consistent with a source centroid offset 300 m beneath and 300 m northwest of the active vents. Similar VLP waveforms are observed at all 21 stations, indicating that the seismograms are source-dominated. The VLP ground displacement response to each explosion may be qualitatively interpreted as: (1) pressurization of the conduit associated with the ascent of a slug of gas; (2) depressurization of the conduit in response to mass withdrawal during the eruption; and (3) repressurization of the conduit associated with the replenishment of the source with fluid. Copyright 1999 by the American Geophysical Union.

Dense Seismic Recordings of Two Surface-Detonated Chemical Explosions

NASA Astrophysics Data System (ADS)

Koper, K. D.; Hale, J. M.; Burlacu, R.; Goddard, K. J.; Trow, A.; Linville, L. M.; Stein, J. R.; Drobeck, D.; Leidig, M.

2015-12-01

In the summer of 2015 two controlled chemical explosions were carried out near Dugway, Utah. The 2 June 2015 explosion consisted of 30,000 lbs of ammonium nitrate fuel oil (ANFO) and the 22 July 2015 explosion consisted of 60,000 lbs of ANFO. The explosion centroids were 1-2 m above the Earth's surface and both created significant craters in the soft desert alluvium. To better understand the seismic source associated with surface explosions, we deployed an array of wireless, three-component, short-period (5 Hz corner frequency) seismometers for several days around each shot. For the first explosion, 46 receivers were deployed in a "lollipop" geometry that had a sparse ring at a radius of 1 km, and a dense stem with 100 m spacing for distances of 0.5-4.5 km. For the second explosion, 48 receivers were deployed similarly, but with a dense ring spaced in azimuthal increments of 10 degrees at a distance of 1 km, and a sparse stem (~500 m spacing) that extended to a distance of nearly 6 km. A rich variety of phases were recorded including direct P waves, refracted and reflected P waves, nearly monochromatic air-coupled Rayleigh waves, normally dispersed fundamental mode Rayleigh waves (Rg), primary airblast arrivals, some secondary airblast arrivals, and possibly tertiary airblast arrivals. There is also evidence of converted S waves on the radial components and possibly direct S energy on the radial and transverse components, although the transverse energy does not always possess a simple, coherent move-out with distance, implying that it might have a scattering origin. To aid in the phase identification, especially of the apparent SH and Love energy, we are currently performing tau-p, f-k, and particle motion analysis.

Ultraviolet Resonance Raman Enhancements in the Detection of Explosives

DTIC Science & Technology

2009-06-01

nitramines (e.g., RDX , HMX ) and aromatic compounds (e.g., DNT, TATB, TNT). 1. Types of Explosives and Chemical Composition Due to stability...resonance Raman spectra of TNT, RDX , HMX , and PETN using 40 UV wavelengths from 210 to 280 nm using a 90 collection geometry [32]. This study includes...Raman can result in a dramatic increase in the Raman scattering efficiency of select band(s) associated with the electronic transition . Other than

Density Estimation for New Solid and Liquid Explosives

DTIC Science & Technology

1977-02-17

The group additivity approach was shown to be applicable to density estimation. The densities of approximately 180 explosives and related compounds... of very diverse compositions were estimated, and almost all the estimates were quite reasonable. Of the 168 compounds for which direct comparisons...could be made (see Table 6), 36.9% of the estimated densities were within 1% of the measured densities, 33.3% were within 1-2%, 11.9% were within 2-3

Residual Stress Development in Explosive-Bonded Bi-Metal Composite Materials

DTIC Science & Technology

2014-03-01

at ANSTO, researching high temperature fatigue behaviour and modelling of ferritic pressure vessel steel , for which he was awarded the degree at...solidification cracking in steels and stainless steels . He has also undertaken extensive work on improving the weld zone toughness of high strength steels ...957. [3] I. Tatsukawa, I. Oda, ‘Residual Stress Measurements on Explosive Clad Stainless Steel ’, Trans. Japan Welding Soc., 2(2), 1971, p26-34

Tephra from the 1979 soufriere explosive eruption.

PubMed

Sigurdsson, H

1982-06-04

The explosive phase of the 1979 Soufriere eruption produced 37.5 x 10(6) cubic meters (dense-rock equivalent) of tephra, consisting of about 40 percent juvenile basaltic andesite and 60 percent of a nonjuvenile component derived from the fragmentation of the 1971-1972 lava island during phreatomagmatic explosions. The unusually fine grain size, poor sorting, and bimodality of the land deposit are attributed to particle aggregation and the formation of accretionary lapilli in a wet eruption column.

Geologic map of the central San Juan caldera cluster, southwestern Colorado

USGS Publications Warehouse

Lipman, Peter W.

2006-01-01

The San Juan Mountains are the largest erosional remnant of a composite volcanic field that covered much of the southern Rocky Mountains in middle Tertiary time. The San Juan field consists mainly of intermediate-composition lavas and breccias, erupted about 35-30 Ma from scattered central volcanoes (Conejos Formation) and overlain by voluminous ash-flow sheets erupted from caldera sources. In the central San Juan Mountains, eruption of at least 8,800 km3 of dacitic-rhyolitic magma as nine major ash flow sheets (individually 150-5,000 km3) was accompanied by recurrent caldera subsidence between 28.3 Ma and about 26.5 Ma. Voluminous andesitic-dacitic lavas and breccias erupted from central volcanoes prior to the ash-flow eruptions, and similar lava eruptions continued within and adjacent to the calderas during the period of more silicic explosive volcanism. Exposed calderas vary in size from 10 to 75 km in maximum dimension; the largest calderas are associated with the most voluminous eruptions.

A novel method for the measurement of the von Neumann spike in detonating high explosives

NASA Astrophysics Data System (ADS)

Sollier, A.; Bouyer, V.; Hébert, P.; Doucet, M.

2016-06-01

We present detonation wave profiles measured in T2 (97 wt. % TATB) and TX1 (52 wt. % TATB and 45 wt. % HMX) high explosives. The experiments consisted in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. Free surface velocity wave profiles were measured at the explosive/air interface using a Photon Doppler Velocimetry system. We demonstrate that a comparison of these free surface wave profiles with those measured at explosive/window interfaces in similar conditions allows to bracket the von Neumann spike in a narrow range. For T2, our measurements show that the spike pressure lies between 35.9 and 40.1 GPa, whereas for TX1, it lies between 42.3 and 47.0 GPa. The numerical simulations performed in support to these measurements show that they can be used to calibrate reactive burn models and also to check the accuracy of the detonation products equation of state at low pressure.

Liquid explosions induced by X-ray laser pulses

DOE PAGES

Stan, Claudiu A.; Milathianaki, Despina; Laksmono, Hartawan; ...

2016-05-23

Explosions are spectacular and intriguing phenomena that expose the dynamics of matter under extreme conditions. We investigated, using time-resolved imaging, explosions induced by ultraintense X-ray laser pulses in water drops and jets. Our observations revealed an explosive vaporization followed by high-velocity interacting flows of liquid and vapour, and by the generation of shock trains in the liquid jets. These flows are different from those previously observed in laser ablation, owing to a simpler spatial pattern of X-ray absorption. We show that the explosion dynamics in our experiments is consistent with a redistribution of absorbed energy, mediated by a pressure ormore » shock wave in the liquid, and we model the effects of explosions, including their adverse impact on X-ray laser experiments. As a result, X-ray laser explosions have predictable dynamics that may prove useful for controlling the state of pure liquids over broad energy scales and timescales, and for triggering pressure-sensitive molecular dynamics in solutions.« less

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.

Design of SC walls and slabs for impulsive loading

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

Varma, Amit H.

2015-11-11

Reinforced concrete (RC) structures have historically been the preferred choice for blast resistant structures because of their mass and the ductility provided by steel reinforcement. Steel-plate composite (SC) walls are a viable alternative to RC for protecting the infrastructure against explosive threats. SC structures consist of two steel faceplates with a plain concrete core between them. The steel faceplates are anchored to the concrete using stud anchors and connected to each other using tie bars. SC structures provide mass from the concrete infill and ductility from the continuous external steel faceplates. This dissertation presents findings and recommendations from experimental andmore » analytical investigations of the performance of SC walls subjected to far-field blast loads.« less

Interpenetrated Binary Supramolecular Nanofibers for Sensitive Fluorescence Detection of Six Classes of Explosives.

PubMed

Xiong, Wei; Zhu, Qijian; Gong, Yanjun; Wang, Chen; Che, Yanke; Zhao, Jincai

2018-04-03

In this work, we develop a sequential self-assembly approach to fabricate interpenetrated binary supramolecular nanofibers consisting of carbazole oligomer 1-cobalt(II) (1-Co 2+ ) coordination nanofibers and oligomer 2 nanofibers for the sensitive detection of six classes of explosives. When exposed to peroxide explosives (e.g., H 2 O 2 ), Co 2+ in 1-Co 2+ coordination nanofibers can be reduced to Co + that can transfer an electron to the excited 2 nanofibers and thereby quench their fluorescence. On the other hand, when exposed to the other five classes of explosives, the excited 2 nanofibers can transfer an electron to explosives to quench their fluorescence. On the basis of the distinct fluorescence quenching mechanisms, six classes of explosives can be sensitively detected. Herein, we provide a new strategy to design broad-band fluorescence sensors for a rich identification of threats.

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.

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.

Implementation of a High Explosive Equation of State into an Eulerian Hydrocode

NASA Astrophysics Data System (ADS)

Littlefield, David L.; Baker, Ernest L.

2004-07-01

The implementation of a high explosive equation of state into the Eulerian hydrocode CTH is described. The equation of state is an extension to JWL referred to as JWLB, and is intended to model the thermodynamic state of detonation products from a high explosive reaction. The EOS was originally cast in a form p = p(ρ, e), where p is the pressure, ρ is the density and e is the internal energy. However, the target application code requires an EOS of the form p = p(ρ, T), where T is the temperature, so it was necessary to reformulate the EOS in a thermodynamically consistent manner. A Helmholtz potential, developed from the original EOS, insures this consistency. Example calculations are shown that illustrate the veracity of this implementation.

49 CFR 173.52 - Classification codes and compatibility groups of explosives.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Classification codes and compatibility groups of... Class 1 § 173.52 Classification codes and compatibility groups of explosives. (a) The classification..., consists of the division number followed by the compatibility group letter. Compatibility group letters are...

Energetic lanthanide complexes: coordination chemistry and explosives applications

NASA Astrophysics Data System (ADS)

Manner, V. W.; Barker, B. J.; Sanders, V. E.; Laintz, K. E.; Scott, B. L.; Preston, D. N.; Sandstrom, M.; Reardon, B. L.

2014-05-01

Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

Energetic Lanthanide Complexes: Coordination Chemistry and Explosives Applications

NASA Astrophysics Data System (ADS)

Manner, Virginia; Barker, Beau; Sanders, Eric; Laintz, Kenneth; Scott, Brian; Preston, Daniel; Sandstrom, Mary; Reardon, Bettina

2013-06-01

Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with ``tailor made'' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

Energy transfer through a multi-layer liner for shaped charges

DOEpatents

Skolnick, Saul; Goodman, Albert

1985-01-01

This invention relates to the determination of parameters for selecting materials for use as liners in shaped charges to transfer the greatest amount of energy to the explosive jet. Multi-layer liners constructed of metal in shaped charges for oil well perforators or other applications are selected in accordance with the invention to maximize the penetrating effect of the explosive jet by reference to four parameters: (1) Adjusting the explosive charge to liner mass ratio to achieve a balance between the amount of explosive used in a shaped charge and the areal density of the liner material; (2) Adjusting the ductility of each layer of a multi-layer liner to enhance the formation of a longer energy jet; (3) Buffering the intermediate layers of a multi-layer liner by varying the properties of each layer, e.g., composition, thickness, ductility, acoustic impedance and areal density, to protect the final inside layer of high density material from shattering upon impact of the explosive force and, instead, flow smoothly into a jet; and (4) Adjusting the impedance of the layers in a liner to enhance the transmission and reduce the reflection of explosive energy across the interface between layers.

The spatial distribution patterns of condensed phase post-blast explosive residues formed during detonation.

PubMed

Abdul-Karim, Nadia; Blackman, Christopher S; Gill, Philip P; Karu, Kersti

2016-10-05

The continued usage of explosive devices, as well as the ever growing threat of 'dirty' bombs necessitates a comprehensive understanding of particle dispersal during detonation events in order to develop effectual methods for targeting explosive and/or additive remediation efforts. Herein, the distribution of explosive analytes from controlled detonations of aluminised ammonium nitrate and an RDX-based explosive composition were established by systematically sampling sites positioned around each firing. This is the first experimental study to produce evidence that the post-blast residue mass can distribute according to an approximate inverse-square law model, while also demonstrating for the first time that distribution trends can vary depending on individual analytes. Furthermore, by incorporating blast-wave overpressure measurements, high-speed imaging for fireball volume recordings, and monitoring of environmental conditions, it was determined that the principle factor affecting all analyte dispersals was the wind direction, with other factors affecting specific analytes to varying degrees. The dispersal mechanism for explosive residue is primarily the smoke cloud, a finding which in itself has wider impacts on the environment and fundamental detonation theory. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Empirical Observations of Earthquake-Explosion Discrimination Using P/S Ratios and Implications for the Sources of Explosion S-Waves

DTIC Science & Technology

2007-09-01

stations at test sites around the world (e.g., Nevada, Lop Nor, Novaya Zemlya, Semipalatinsk , India, Pakistan, and North Korea). We show this pattern...regional P/S amplitudes tended to be dominated by frequencies around 1 Hz. As shown in Figure 2 at a number of major nuclear test sites , these...Figure 2. Bandpass filtered 1-2 Hz seismograms of earthquake (red) and explosion (blue) pairs at nuclear test sites show little consistent

Communication: Gas-phase structural isomer identification by Coulomb explosion of aligned molecules

NASA Astrophysics Data System (ADS)

Burt, Michael; Amini, Kasra; Lee, Jason W. L.; Christiansen, Lars; Johansen, Rasmus R.; Kobayashi, Yuki; Pickering, James D.; Vallance, Claire; Brouard, Mark; Stapelfeldt, Henrik

2018-03-01

The gas-phase structures of four difluoroiodobenzene and two dihydroxybromobenzene isomers were identified by correlating the emission angles of atomic fragment ions created, following femtosecond laser-induced Coulomb explosion. The structural determinations were facilitated by confining the most polarizable axis of each molecule to the detection plane prior to the Coulomb explosion event using one-dimensional laser-induced adiabatic alignment. For a molecular target consisting of two difluoroiodobenzene isomers, each constituent structure could additionally be singled out and distinguished.

Analysis and Simulation of Near-Field Wave Motion Data from the Source Physics Experiment Explosions

DTIC Science & Technology

2011-09-01

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. A complimentary

Raman lidar for remote control explosives in the subway

NASA Astrophysics Data System (ADS)

Grishkanich, Aleksandr; Redka, Dmitriy; Vasiliev, Sergey; Tishkov, Victor; Zhevlakov, Aleksandr

2017-10-01

Laser sensing can serve as a highly effective method of searching and monitoring of explosives in the subway. The first method is essence consists in definition the explosives concentration by excitation and registration ramans shifts at wavelength of λ = 0.261 - 0.532 μm at laser sounding. Preliminary results of investigation show the real possibility to register of 2,4,6-trinitrophenylmethylnitramine with concentration on surface at level of 108÷109 cm-3 on a safe distance 50 m from the object.

75 FR 25879 - Notice of Proposed Supplementary Rules Concerning Fireworks on Public Land in Colorado

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-10

... thirty milligrams of explosive material, aerial shells containing more than forty grams of pyrotechnic..., total pyrotechnic composition not to exceed seventy-five grams each for a single tube or, when more than... grams; (II) Cone fountains, total pyrotechnic composition not to exceed fifty grams each for a single...

Ageing of Insensitive DNAN Based Melt-Cast Explosives

DTIC Science & Technology

2014-08-01

diurnal cycle (representative of the MEAO climate). Analysis of the ingredient composition, sensitiveness, mechanical and thermal properties was...first test condition was chosen to provide a worst-case scenario. Analysis of the ingredient composition, theoretical maximum density, sensitiveness...5 4.1.1 ARX-4027 Ingredient Analysis .............................................................. 5 4.1.2 ARX-4028 Ingredient Analysis

Post-Detonation Energy Release from TNT-Aluminum Explosives

NASA Astrophysics Data System (ADS)

Zhang, Fan; Anderson, John; Yoshinaka, Akio

2007-06-01

Detonation and post-detonation energy release from TNT and TNT-aluminum composite have been experimentally studied in an air-filled chamber, 26 m^3 in volume and 3 m in diameter. While TNT has a high oxygen deficiency, experiments with 1.1 kg to 4 kg charges yield energy releases reaching only 86% of theoretical equilibrium values, possibly due to the non-uniform mixing between the detonation products and air. In order to improve mixing and further increase afterburning energy, large mass fractions of large aluminum particles are combined with TNT. The effect of particle distribution is also investigated in two composite configurations, whereby the aluminum particles are uniformly mixed in cast TNT or arranged in a shell surrounding a TNT cylinder. It is shown that the TNT-aluminum composite outperforms pure TNT, while improved performance is achieved for the shell configuration due to enhanced spatial mixing of hot fuels with oxidizing gases. Comparisons with the equilibrium theory and a liquid-based aluminized composite explosive (with an oxygen deficiency less than that of TNT) are conducted to further explore the mixing and afterburning mechanism.

Buckybomb: Reactive Molecular Dynamics Simulation

DOE PAGES

Chaban, Vitaly V.; Fileti, Eudes Eterno; Prezhdo, Oleg V.

2015-02-24

Energetic materials, such as explosives, propellants, and pyrotechnics, are widely used in civilian and military applications. Nanoscale explosives represent a special group because of the high density of energetic covalent bonds. The reactive molecular dynamics (ReaxFF) study of nitrofullerene decomposition reported here provides a detailed chemical mechanism of explosion of a nanoscale carbon material. Upon initial heating, C 60(NO 2) 12 disintegrates, increasing temperature and pressure by thousands of Kelvins and bars within tens of picoseconds. The explosion starts with NO 2 group isomerization into C-O-N-O, followed by emission of NO molecules and formation of CO groups on the buckyballmore » surface. NO oxidizes into NO 2, and C 60 falls apart, liberating CO 2. At the highest temperatures, CO 2 gives rise to diatomic carbon. Lastly, the study shows that the initiation temperature and released energy depend strongly on the chemical composition and density of the material.« less

Correlation of cycles in Lava Lake motion and degassing at Erebus Volcano, Antarctica

NASA Astrophysics Data System (ADS)

Peters, Nial; Oppenheimer, Clive; Killingsworth, Drea Rae; Frechette, Jed; Kyle, Philip

2014-08-01

Several studies at Erebus volcano have recorded pulsatory behavior in many of the observable properties of its active lava lake. A strong correlation between the variations in surface speed of the lake and the composition of gas emitted has previously been noted. While previous studies have shown that the SO2 flux and the surface elevation exhibit pulsatory behavior with a similar period to that of the surface speed and gas composition, suggesting they are linked, a lack of overlap between the different measurements has prevented direct comparisons from being made. Using high time-resolution measurements of surface elevation, surface speed, gas composition, and SO2 flux, we demonstrate for the first time an unambiguous link between the cyclic behavior in each of these properties. We also show that the variation in gas composition may be explained by a subtle change in oxygen fugacity. The cycles are found to be in-phase with each other, with a small but consistent lag of 1-3 min between the peaks in surface elevation and surface speed. Explosive events are found to have no observable effect on the pulsatory behavior beyond the ˜5 min period required for lake refill. The close correspondences between the varying lake surface motion, gas flux and composition, and modeled oxygen fugacity suggest strong links between magma degassing, redox change, and the fluid dynamics of the shallow magmatic system.

Iron and nickel isotope compositions of presolar silicon carbide grains from supernovae

NASA Astrophysics Data System (ADS)

Kodolányi, János; Stephan, Thomas; Trappitsch, Reto; Hoppe, Peter; Pignatari, Marco; Davis, Andrew M.; Pellin, Michael J.

2018-01-01

We report the carbon, silicon, iron, and nickel isotope compositions of twenty-five presolar SiC grains of mostly supernova (SN) origin. The iron and nickel isotope compositions were measured with the new Chicago Instrument for Laser Ionization, CHILI, which allows the analysis of all iron and nickel isotopes without the isobaric interferences that plagued previous measurements with the NanoSIMS. Despite terrestrial iron and nickel contamination, significant isotopic anomalies in 54Fe/56Fe, 57Fe/56Fe, 60Ni/58Ni, 61Ni/58Ni, 62Ni/58Ni, and 64Ni/58Ni were detected in nine SN grains (of type X). Combined multi-isotope data of three grains with the largest nickel isotope anomalies (>100‰ or <-100‰ in at least one isotope ratio, when expressed as deviation from the solar value) are compared with the predictions of two SN models, one with and one without hydrogen ingestion in the He shell prior to SN explosion. One grain's carbon-silicon-iron-nickel isotope composition is consistent with the prediction of the model without hydrogen ingestion, whereas the other two grains' isotope anomalies could not be reproduced using either SN models. The discrepancies between the measured isotope compositions and model predictions may indicate element fractionation in the SN ejecta prior to or during grain condensation, and reiterate the need for three-dimensional SN models.

Shock wave induced condensation in fuel-rich gaseous and gas-particles mixtures

NASA Astrophysics Data System (ADS)

Fomin, P. A.

2018-03-01

The possibility of fuel vapor condensation in shock waves in fuel-rich (cyclohexane-oxygen) gaseous mixtures and explosion safety aspects of this effect are discussed. It is shown, that condensation process can essentially change the chemical composition of the gas. For example, the molar fraction of the oxidizer can increase in a few times. As a result, mixtures in which the initial concentration of fuel vapor exceeds the Upper Flammability Limit can, nevertheless, explode, if condensation shifts the composition of the mixture into the ignition region. The rate of the condensation process is estimated. This process can be fast enough to significantly change the chemical composition of the gas and shift it into the flammable range during the compression phase of blast waves, generated by explosions of fuel-vapor clouds or rapture of pressurized chemical reactors, with characteristic size of a few meters. It is shown that the presence of chemically inert microparticles in the gas mixtures under consideration increases the degree of supercooling and the mass of fuel vapors that have passed into the liquid and reduces the characteristic condensation time in comparison with the gas mixture without microparticles. The fuel vapor condensation should be taken into account in estimation the explosion hazard of chemical reactors, industrial and civil constructions, which may contain fuel-rich gaseous mixtures of heavy hydrocarbons with air.

Prevalence of DSM-IV Intermittent Explosive Disorder in Black Adolescents: Findings from the National Survey of American Life, Adolescent Supplement

PubMed Central

Oliver, Diane Graves; Caldwell, Cleopatra H.; Faison, Nakesha; Sweetman, Julie; Abelson, Jamie M.; Jackson, James S.

2016-01-01

Little is known about the epidemiology of DSM-IV intermittent explosive disorder (IED) in adolescents and no information is currently available regarding the relationship between race/ethnicity and IED among Black youth in the US. Using the World Health Organization World Mental Health Composite International Diagnostic Interview (Adolescent Version), we estimated the prevalence, severity, and disability of IED in a national, probability sample of African American and Caribbean Black youth (ages 13-17) from the National Survey of American Life, Adolescent Supplement. Face-to-face surveys of 810 African American and 360 Caribbean Black youth were conducted between 2001 and 2003. We calculated lifetime and 12-month diagnoses of IED using diagnostic algorithms based on DSM-IV and assessed IED disability using a modified Sheehan Disability Scale. Overall findings indicated lifetime and 12-month IED prevalence rates of 9.2% and 7.0%, respectively. Lifetime prevalence rates of IED were 9.0 % for African American and 12.4% for Caribbean Black teens. Within the past 12 months 6.7% of African American and 11.5% of Caribbean Black adolescents met diagnostic criteria for IED. Lifetime and 12-month IED were associated with anxiety disorders. In addition, few teens with lifetime IED received any treatment. Findings are consistent with recent evidence that intermittent explosive disorder may be more common than previously considered, especially among adolescents. Significant acts of aggression and impairment are associated with IED and low treatment rates indicate that more research on this disorder and intervention options is warranted. PMID:27078052

Recovery in Level 7-10 Women's USA Artistic Gymnastics.

PubMed

Buckner, Stephen B; Bacon, Nicholas T; Bishop, Phillip A

2017-01-01

This study assessed physical performance in women's artistic gymnastics following three variable recovery periods. Participants included fifteen female gymnasts (mean age = 13.5 ± 1.1) who had competed at USA Gymnastics (USAG) levels 7 - 10 within at least one year prior to the study. Each testing session consisted of a warm-up followed by four muscular endurance tests and one explosive maximal test. Assessments included pull-ups, leg lifts, handstand push-ups, vertical jump, and push-ups. After the performance assessments, the participants completed a typical practice session. The performance measures were reassessed at the beginning of each of the recovery periods of 24, 48, and 72 hours in a counterbalanced design. Performance assessments were converted into Z-scores and then averaged for a composite session Z-score. The composite session Z-scores were compared to evaluate the recovery duration. Composite Z's were significantly lower (p=0.000), after the 24 (z=-1.10) and the 48 hour (z=-0.71) recovery periods compared to baseline (z=0.00). However, there was no difference in scores (p=1.00) between the baseline and 72 hours (z=0.004) recovery. Full recovery required 72 hours under the conditions of this study.

Green primary explosives: 5-Nitrotetrazolato-N2-ferrate hierarchies

PubMed Central

Huynh, My Hang V.; Coburn, Michael D.; Meyer, Thomas J.; Wetzler, Modi

2006-01-01

The sensitive explosives used in initiating devices like primers and detonators are called primary explosives. Successful detonations of secondary explosives are accomplished by suitable sources of initiation energy that is transmitted directly from the primaries or through secondary explosive boosters. Reliable initiating mechanisms are available in numerous forms of primers and detonators depending upon the nature of the secondary explosives. The technology of initiation devices used for military and civilian purposes continues to expand owing to variations in initiating method, chemical composition, quantity, sensitivity, explosive performance, and other necessary built-in mechanisms. Although the most widely used primaries contain toxic lead azide and lead styphnate, mixtures of thermally unstable primaries, like diazodinitrophenol and tetracene, or poisonous agents, like antimony sulfide and barium nitrate, are also used. Novel environmentally friendly primary explosives are expanded here to include cat[FeII(NT)3(H2O)3], cat2[FeII(NT)4(H2O)2], cat3[FeII(NT)5(H2O)], and cat4[FeII(NT)6] with cat = cation and NT− = 5-nitrotetrazolato-N2. With available alkaline, alkaline earth, and organic cations as partners, four series of 5-nitrotetrazolato-N2-ferrate hierarchies have been prepared that provide a plethora of green primaries with diverse initiating sensitivity and explosive performance. They hold great promise for replacing not only toxic lead primaries but also thermally unstable primaries and poisonous agents. Strategies are also described for the systematic preparation of coordination complex green primaries based on appropriate selection of ligands, metals, and synthetic procedures. These strategies allow for maximum versatility in initiating sensitivity and explosive performance while retaining properties required for green primaries. PMID:16803957

Green primary explosives: 5-nitrotetrazolato-N2-ferrate hierarchies.

PubMed

Huynh, My Hang V; Coburn, Michael D; Meyer, Thomas J; Wetzler, Modi

2006-07-05

The sensitive explosives used in initiating devices like primers and detonators are called primary explosives. Successful detonations of secondary explosives are accomplished by suitable sources of initiation energy that is transmitted directly from the primaries or through secondary explosive boosters. Reliable initiating mechanisms are available in numerous forms of primers and detonators depending upon the nature of the secondary explosives. The technology of initiation devices used for military and civilian purposes continues to expand owing to variations in initiating method, chemical composition, quantity, sensitivity, explosive performance, and other necessary built-in mechanisms. Although the most widely used primaries contain toxic lead azide and lead styphnate, mixtures of thermally unstable primaries, like diazodinitrophenol and tetracene, or poisonous agents, like antimony sulfide and barium nitrate, are also used. Novel environmentally friendly primary explosives are expanded here to include cat[Fe(II)(NT)(3)(H(2)O)(3)], cat(2)[Fe(II)(NT)(4)(H(2)O)(2)], cat(3)[Fe(II)(NT)(5)(H(2)O)], and cat(4)[Fe(II)(NT)(6)] with cat = cation and NT(-) = 5-nitrotetrazolato-N(2). With available alkaline, alkaline earth, and organic cations as partners, four series of 5-nitrotetrazolato-N(2)-ferrate hierarchies have been prepared that provide a plethora of green primaries with diverse initiating sensitivity and explosive performance. They hold great promise for replacing not only toxic lead primaries but also thermally unstable primaries and poisonous agents. Strategies are also described for the systematic preparation of coordination complex green primaries based on appropriate selection of ligands, metals, and synthetic procedures. These strategies allow for maximum versatility in initiating sensitivity and explosive performance while retaining properties required for green primaries.

Pretreatment efficiency and structural characterization of rice straw by an integrated process of dilute-acid and steam explosion for bioethanol production.

PubMed

Chen, Wen-Hua; Pen, Ben-Li; Yu, Ching-Tsung; Hwang, Wen-Song

2011-02-01

The combined pretreatment of rice straw using dilute-acid and steam explosion followed by enzymatic hydrolysis was investigated and compared with acid-catalyzed steam explosion pretreatment. In addition to measuring the chemical composition, including glucan, xylan and lignin content, changes in rice straw features after pretreatment were investigated in terms of the straw's physical properties. These properties included crystallinity, surface area, mean particle size and scanning electron microscopy imagery. The effect of acid concentration on the acid-catalyzed steam explosion was studied in a range between 1% and 15% acid at 180°C for 2 min. We also investigated the influence of the residence time of the steam explosion in the combined pretreatment and the optimum conditions for the dilute-acid hydrolysis step in order to develop an integrated process for the dilute-acid and steam explosion. The optimum operational conditions for the first dilute-acid hydrolysis step were determined to be 165°C for 2 min with 2% H(2)SO(4) and for the second steam explosion step was to be carried out at 180°C for 20 min; this gave the most favorable combination in terms of an integrated process. We found that rice straw pretreated by the dilute-acid/steam explosions had a higher xylose yield, a lower level of inhibitor in the hydrolysate and a greater degree of enzymatic hydrolysis; this resulted in a 1.5-fold increase in the overall sugar yield when compared to the acid-catalyzed steam explosion. Copyright © 2010 Elsevier Ltd. All rights reserved.

A Wolf-Rayet-like progenitor of SN 2013cu from spectral observations of a stellar wind.

PubMed

Gal-Yam, Avishay; Arcavi, I; Ofek, E O; Ben-Ami, S; Cenko, S B; Kasliwal, M M; Cao, Y; Yaron, O; Tal, D; Silverman, J M; Horesh, A; De Cia, A; Taddia, F; Sollerman, J; Perley, D; Vreeswijk, P M; Kulkarni, S R; Nugent, P E; Filippenko, A V; Wheeler, J C

2014-05-22

The explosive fate of massive Wolf-Rayet stars (WRSs) is a key open question in stellar physics. An appealing option is that hydrogen-deficient WRSs are the progenitors of some hydrogen-poor supernova explosions of types IIb, Ib and Ic (ref. 2). A blue object, having luminosity and colours consistent with those of some WRSs, has recently been identified in pre-explosion images at the location of a supernova of type Ib (ref. 3), but has not yet been conclusively determined to have been the progenitor. Similar work has so far only resulted in non-detections. Comparison of early photometric observations of type Ic supernovae with theoretical models suggests that the progenitor stars had radii of less than 10(12) centimetres, as expected for some WRSs. The signature of WRSs, their emission line spectra, cannot be probed by such studies. Here we report the detection of strong emission lines in a spectrum of type IIb supernova 2013cu (iPTF13ast) obtained approximately 15.5 hours after explosion (by 'flash spectroscopy', which captures the effects of the supernova explosion shock breakout flash on material surrounding the progenitor star). We identify Wolf-Rayet-like wind signatures, suggesting a progenitor of the WN(h) subclass (those WRSs with winds dominated by helium and nitrogen, with traces of hydrogen). The extent of this dense wind may indicate increased mass loss from the progenitor shortly before its explosion, consistent with recent theoretical predictions.

A Wolf-Rayet-Like Progenitor of SN 2013cu from Spectral Observations of a Stellar Wind

NASA Technical Reports Server (NTRS)

Gal-Yam, Avishay; Arcavi, I.; Ofek, E. O.; Ben-Ami, S.; Cenko, S. B.; Kasliwal, M. M.; Cao, Y.; Yaron, O.; Tal, D.; Silverman, J. M.;

Using late-time optical and near-infrared spectra to constrain Type Ia supernova explosion properties

NASA Astrophysics Data System (ADS)

Maguire, K.; Sim, S. A.; Shingles, L.; Spyromilio, J.; Jerkstrand, A.; Sullivan, M.; Chen, T.-W.; Cartier, R.; Dimitriadis, G.; Frohmaier, C.; Galbany, L.; Gutiérrez, C. P.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Rudy, R.; Sollerman, J.

2018-03-01

The late-time spectra of Type Ia supernovae (SNe Ia) are powerful probes of the underlying physics of their explosions. We investigate the late-time optical and near-infrared spectra of seven SNe Ia obtained at the VLT with XShooter at >200 d after explosion. At these epochs, the inner Fe-rich ejecta can be studied. We use a line-fitting analysis to determine the relative line fluxes, velocity shifts, and line widths of prominent features contributing to the spectra ([Fe II], [Ni II], and [Co III]). By focussing on [Fe II] and [Ni II] emission lines in the ˜7000-7500 Å region of the spectrum, we find that the ratio of stable [Ni II] to mainly radioactively-produced [Fe II] for most SNe Ia in the sample is consistent with Chandrasekhar-mass delayed-detonation explosion models, as well as sub-Chandrasekhar mass explosions that have metallicity values above solar. The mean measured Ni/Fe abundance of our sample is consistent with the solar value. The more highly ionised [Co III] emission lines are found to be more centrally located in the ejecta and have broader lines than the [Fe II] and [Ni II] features. Our analysis also strengthens previous results that SNe Ia with higher Si II velocities at maximum light preferentially display blueshifted [Fe II] 7155 Å lines at late times. Our combined results lead us to speculate that the majority of normal SN Ia explosions produce ejecta distributions that deviate significantly from spherical symmetry.

Compositional and Textural Analysis of Maar-Diatreme Volcanic Deposits at Hopi Buttes Volcanic Field (AZ) Using GigaPan Panoramic and Thermal Infrared Imagery

NASA Astrophysics Data System (ADS)

Lee, R.; Graettinger, A. H.; Weinell, M.; Hughes, C. G.

2016-12-01

Basaltic maar-diatreme volcanoes are produced when rising magma interacts with groundwater and produces a maar crater at the ground surface. This crater is underlain by a diatreme, a downward-tapering conical structure filled with a mixture of fragments of intruded magma, fractured host rock, and clasts recycled through repeated discrete subsurface explosions. The debris of the diatreme records the mixing processes caused by subsurface explosions and is the source for ejected material that forms maar tephra rings. Determining the variable depths and lateral locations of these explosions and how energy is dissipated in the subsurface is critical to understanding how maar-diatreme eruptions progress. The Hopi Buttes Volcanic Field (HBVF) in the Navajo Nation, Arizona, USA, contains several diatremes and incised tephra rings with heterolithic clasts 10 mm - 10 m in size, and are well-exposed near-vertical to vertical outcrops. Our ability to measure the length scales and distribution of textures produced by subsurface explosions in these diatremes is limited by the physical accessibility of the exposures, due to both the verticality of the outcrops and the cultural sensitivity of the site. Quantifying the number and locations of explosions is dependent on our ability to investigate the full diatreme outcrop, and not just what can be accessed through traditional field observations. We present a novel field and computer-based technique for both quantitatively and qualitatively characterizing the composition and texture of maar-diatreme deposits in vertical outcrops. This technique uses a combination of field-collected multispectral thermal infrared (TIR) image data and visible wavelength GigaPan imagery to characterize the compositional and textural variations over a whole outcrop. To increase the spatial and spectral resolution of the TIR data, a super-resolution technique will be applied. The technique provides a simple and efficient method to augment the study of the maar-diatreme deposits at HBVF. In addition to contributing to a better understanding of the formation processes of maar-diatreme deposits around the world, the technique also shows great promise for studies involving other types of large outcrops and geologic structures.

The Possibility of Using Composite Nanoparticles in High Energy Materials

NASA Astrophysics Data System (ADS)

Komarova, M. V.; Vorozhtsov, A. B.; Wakutin, A. G.

2017-01-01

The effect of nanopowders on the burning rate varying with the metal content in mixtures of different high energy composition is investigated. Experiments were performed on compositions based on an active tetrazol binder and electroexplosive nanoaluminum with addition of copper, nickel, or iron nanopowders, and of Al-Ni, Al-Cu, or Al-Fe composite nanoparticles produced by electrical explosion of heterogeneous metal wires. The results obtained from thermogravimetric analysis of model metal-based compositions are presented. The advantages of the composite nanoparticles and the possibility of using them in high energy materials are discussed.

Stoichiometry and possible mechanism of SiH/sub 4/-O/sub 2/ explosions

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

Hartman, J.R.; Famil-Ghiriha, J.; Ring, M.A.

1987-04-01

The products of silane-O/sub 2/ mixture explosions vary with mixture composition. For O/sub 2/-rich mixtures (>70% O/sub 2/), the products are H/sub 2/O and SiO/sub 2/. As the mixtures become richer in silane, H/sub 2/ replaces H/sub 2/O as a final product. For very SiH/sub 4/-rich mixtures (>70% SiH/sub 4/), the products are H/sub 2/, SiO/sub x/, and Si. The fact that silane is totally consumed in silane-rich mixtures (70-90% silane) demonstrates that solid particle formation (SiO/sub 2/, SiO, and Si) occurs very rapidly and that the accompanying heat release is essential to drive the reactions to completion. It ismore » also clear that the explosion of a silane-rich mixture is primarily a thermal explosion of silane. Effects due to problems associated with upper pressure limit measurements and mechanistic aspects of the SiH/sub 4/-O/sub 2/ explosion reaction are discussed.« less

Isotope-Labeled Composition B for Tracing Detonation Signatures

NASA Astrophysics Data System (ADS)

Manner, Virginia; Podlesak, David; Huber, Rachel; Amato, Ronald; Giambra, Anna; Bowden, Patrick; Hartline, Ernest; Dattelbaum, Dana

2017-06-01

To better understand how solid carbon forms and evolves during detonation, we have prepared Composition B with 13 C and 15 N-labeled 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 2,4,6-trinitrotoluene (TNT) in order to trace the formation of soot from the carbon and nitrogen atoms in these explosives. Isotope-labeling of explosives has been performed in the recent past for a variety of reasons, including environmental remediation and reaction mechanism studies. Because it is expensive and time consuming to prepare these materials, and our detection equipment only requires trace amounts of isotopes, we have prepared fully-labeled materials and substituted them into unlabeled RDX and TNT at less than the 1% level. We will discuss the preparation and full characterization of this labeled Composition B, the detonation tests performed, along with the results of the post-detonation soot analysis. Various detonation models predict differing amounts and forms of carbon and nitrogen; these isotopically-labeled precursors have allowed these models to be tested.

Accelerator-Detector Complex for Photonuclear Detection of Hidden Explosives Final Report CRADA No. TC2065.0

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

Lowdermilk, W. H.; Brothers, L. J.

This was a collaborative effort by Lawrence Livermore National Security (formerly the University of California)/Lawrence Livermore National Laboratory (LLNL), Valley Forge Composite Technologies, Inc., and the following Russian Institutes: P. N. Lebedev Physical Institute (LPI), Innovative Technologies Center.(AUO CIT), Central Design Bureau-Almas (CDB Almaz), Moscow Instrument Automation Research Institute, and Institute for High Energy Physics (IBEP) to develop equipment and procedures for detecting explosive materials concealed in airline checked baggage and cargo.

Spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB

DOEpatents

Harris, Betty W.

1986-01-01

A simple, sensitive and specific spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB, is described. Upon the application of the composition of matter of the present invention to samples containing in excess of 0.1 mg of this explosive, a bright orange color results. Interfering species such as TNT and Tetryl can be removed by first treating the sample with a solvent which does not dissolve much of the TATB, but readily dissolves these explosives.

Spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB

DOEpatents

Harris, B.W.

1984-11-29

A simple, sensitive and specific spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB, is described. Upon the application of the composition of matter of the subject invention to samples containing in excess of 0.1 mg of this explosive, a bright orange color results. Interfering species such as TNT and Tetryl can be removed by first treating the sample with a solvent which does not dissolve the TATB, but readily dissolves these interfering explosives.

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

Hobbs, Michael L.

We have previously developed a PBX 9501 cookoff model for the plastic bonded explosive PBX 9501 consisting of 95 wt% octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazoncine (HMX), 2.5 wt% Estane® 5703 (a polyurethane thermoplastic), and 2.5 wt% of a nitroplasticizer (NP): BDNPA/F, a 50/50 wt% eutectic mixture bis(2,2-dinitropropyl)-acetal (BDNPA) and bis(2,2-dinitropropyl)-formal (BDNPF). This fivestep model includes desorption of water, decomposition of the NP to form NO 2, reaction of the NO 2 with Estane and HMX, and decomposition of HMX [1]. This model has been successfully validated with data from six laboratories with scales ranging from 2 g to more than 2.5 kg of explosive.more » We have determined, that the PBX 9501 model can be used to predict cookoff of other plastic bonded explosives containing HMX and an inert binder, such as LX-04 consisting of 85 wt% HMX and 15 wt% Viton A (vinylidine fluoride/hexafluoropropylene copolymer), LX-07 (90 wt% HMX and 10 wt% Viton A), LX- 10-0 (95 wt% HMX and 5 wt% Viton A), and LX-14 consisting of 95.5 wt % HMX and 4.5 wt% Estane® 5702-F1 (a polyurethane thermoplastic). Normally our cookoff models are verified using Sandia’s Instrumented Thermal Initiation (SITI) experiment. However, SITI data for LX-04, LX-07, LX-10-0, and LX-14 are not available at pressed density; although, some molding powder SITI data on LX-10-0 and LX-14 exists. Tarver and Tran [2] provide some one-dimensional time-to-explosion (ODTX) data for these explosives. The applicability of the PBX 9501 model to LX-04, LX-07, LX-10-0, AND LX-14 was made using this ODTX data [2]. The PBX 9501 model is applied to these other explosives by accounting for the correct amount of HMX in the explosive and limiting the NP reaction. We have found the PBX 9501 model to be useful for predicting the response of these PBXs to abnormal thermal environments such as fire.« less

Detection of explosives in soils

DOEpatents

Chambers, William B.; Rodacy, Philip J.; Phelan, James M.; Woodfin, Ronald L.

2002-01-01

An apparatus and method for detecting explosive-indicating compounds in subsurface soil. The apparatus has a probe with an adsorbent material on some portion of its surface that can be placed into soil beneath the ground surface, where the adsorbent material can adsorb at least one explosive-indicating compound. The apparatus additional has the capability to desorb the explosive-indicating compound through heating or solvent extraction. A diagnostic instrument attached to the probe detects the desorbed explosive-indicating compound. In the method for detecting explosive-indicating compounds in soil, the sampling probe with an adsorbent material on at least some portion of a surface of the sampling probe is inserted into the soil to contact the adsorbent material with the soil. The explosive-indicating compounds are then desorbed and transferred as either a liquid or gas sample to a diagnostic tool for analysis. The resulting gas or liquid sample is analyzed using at least one diagnostic tool selected from the group consisting of an ion-mobility spectrometer, a gas chromatograph, a high performance liquid chromatograph, a capillary electrophoresis chromatograph, a mass spectrometer, a Fourier-transform infrared spectrometer and a Raman spectrometer to detect the presence of explosive-indicating compounds.

Three dimensional core-collapse supernova simulated using a 15 M ⊙ progenitor

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

Lentz, Eric J.; Bruenn, Stephen W.; Hix, W. Raphael

We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 M⊙ progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions; however, the onset of explosion (shock revival) is delayed by ~100 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the ~100 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energymore » favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. Finally, we posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.« less

Three dimensional core-collapse supernova simulated using a 15 M ⊙ progenitor

DOE PAGES

Lentz, Eric J.; Bruenn, Stephen W.; Hix, W. Raphael; ...

2015-07-10

We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 M⊙ progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions; however, the onset of explosion (shock revival) is delayed by ~100 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the ~100 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energymore » favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. Finally, we posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.« less

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.

Measuring the Progenitor Masses and Dense Circumstellar Material of Type II Supernovae

NASA Astrophysics Data System (ADS)

Morozova, Viktoriya; Piro, Anthony L.; Valenti, Stefano

2018-05-01

Recent modeling of hydrogen-rich Type II supernova (SN II) light curves suggests the presence of dense circumstellar material (CSM) surrounding the exploding progenitor stars. This has important implications for the activity and structure of massive stars near the end of their lives. Since previous work focused on just a few events, here we expand to a larger sample of 20 well-observed SNe II. For each event we are able to constrain the progenitor zero-age main-sequence (ZAMS) mass, explosion energy, and the mass and radial extent of the dense CSM. We then study the distribution of each of these properties across the full sample of SNe. The inferred ZAMS masses are found to be largely consistent with a Salpeter distribution with minimum and maximum masses of 10.4 and 22.9 M ⊙, respectively. We also compare the individual ZAMS masses we measure with specific SNe II that have pre-explosion imaging to check their consistency. Our masses are generally comparable to or higher than the pre-explosion imaging masses, potentially helping ease the red supergiant problem. The explosion energies vary from (0.1–1.3) × 1051 erg, and for ∼70% of the SNe we obtain CSM masses in the range between 0.18 and 0.83 M ⊙. We see a potential correlation between the CSM mass and explosion energy, which suggests that pre-explosion activity has a strong impact on the structure of the star. This may be important to take into account in future studies of the ability of the neutrino mechanism to explode stars. We also see a possible correlation between the CSM radial extent and ZAMS mass, which could be related to the time with respect to explosion when the CSM is first generated.

Investigation of heat-resistant layered coating of Al-Cr-Ni

NASA Astrophysics Data System (ADS)

Shmorgun, V. G.; Trykov, Y. P.; Bogdanov, A. I.; Taube, A. O.

2016-02-01

The paper shows the transformation of the structure and phase composition of the layered coating system Al-Cr-Ni, obtained by the heat treatment of multilayered composite H20N80+AD1, welded by explosion, in the time range 1-300 hours. The cyclic heat resistance of the coating at 1150 ° C is studied.

Effects Of Rapid Crushing On Composites

NASA Technical Reports Server (NTRS)

Farley, Gary L.

1990-01-01

Experimental study described in NASA technical memorandum performed to determine whether crash energy-absorption capabilities of graphite/epoxy and Kevlar/epoxy composite materials are functions of speed of crushing. Additional objective to develop understanding of mechanisms of crushing. Technology applied to enhancement of safety and crashworthiness of automobiles, design of energy-absorbing devices in machinery, and problems involving explosions and impacts.

24. Duplicate negative of an historic negative. 'AERIAL VIEW OF ...

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

24. Duplicate negative of an historic negative. 'AERIAL VIEW OF AREA 'B' HOLSTON ORDNANCE WORKS.' 1944. #OCMH 4-12.2ASAV3 in Super Explosives Program RDX and Its Composition A, B, & C, Record Group No. 319, National Archives, Washington, D.C. - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

Defence Capability Plan 2009 (Australian Department of Defence). Public Version

DTIC Science & Technology

2009-01-24

workings or Intellectual Property . > Armoured vehicles. This capability relates to the repair, maintenance and some upgrades of specialist military...cryptographic equipment. > Composite and exotic materials. This is the ability to repair specialist alloys and composite materials, to develop new...manufacture of some high usage munitions, ammunition components, propellants and explosives. > Signature management. Includes the capabilities and coatings

49 CFR 173.35 - Hazardous materials in IBCs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... plastic or composite IBC may only be filled with a liquid having a vapor pressure less than or equal to... -57 portable tanks. (j) No IBC may be filled with a Packing Group I liquid. Rigid plastic, composite... point of 60 °C (140 °F) (closed cup) or lower, or powders with the potential for dust explosion...

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.

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

Sollier, A., E-mail: arnaud.sollier@cea.fr; Bouyer, V.; Hébert, P.

We present detonation wave profiles measured in T2 (97 wt. % TATB) and TX1 (52 wt. % TATB and 45 wt. % HMX) high explosives. The experiments consisted in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. Free surface velocity wave profiles were measured at the explosive/air interface using a Photon Doppler Velocimetry system. We demonstrate that a comparison of these free surface wave profiles with those measured at explosive/window interfaces in similar conditions allows to bracket the von Neumann spike in a narrow range. For T2, our measurements show that the spike pressuremore » lies between 35.9 and 40.1 GPa, whereas for TX1, it lies between 42.3 and 47.0 GPa. The numerical simulations performed in support to these measurements show that they can be used to calibrate reactive burn models and also to check the accuracy of the detonation products equation of state at low pressure.« less

Outbursts of H2O in Comet P/Halley

NASA Astrophysics Data System (ADS)

Larson, H. P.; Hu, H.-Y.; Mumma, M. J.; Weaver, H. A.

1990-07-01

Comet Halley gas-production monitoring efforts in March 1986 with the NASA Kuiper Airborne Observatory's Fourier transform spectrometer have indicated rapid temporal variations in H2O emissions; a continuous record of an H2O outburst was thus obtained. The event, in which H2O brightness increased by a factor of 2.2 in less than 10 min, is ascribable to an energetic process in the nucleus whose character may have been that of amorphous H2O ice crystallization, chemical explosion, thermal stress, or a compressed gas pocket. The timing and energy of the event appear to require an internal energy source; amorphous ice crystallization is held to be most consistent with compositional and thermal models of cometary nuclei as well as the observations.

Understanding how active volcanoes work: a contribution from synchrotron X-ray computed microtomography

NASA Astrophysics Data System (ADS)

Polacci, M.; Baker, D. R.; Mancini, L.

2009-04-01

Volcanoes are complex systems that require the integration of many different geoscience disciplines to understand their behaviour and to monitor and forecast their activity. In the last two decades an increasing amount of information on volcanic processes has been obtained by studying the textures and compositions of volcanic rocks. Five years ago we started a continuing collaboration with the SYRMEP beamline of Elettra Sincrotrone, a third generation synchrotron light source near Trieste, Italy, with the goal of performing high-resolution, phase-contrast X-ray tomographic scans and reconstructing 3-D digital volumes of volcanic specimens. These volumes have been then used for the visualization of the internal structure of rocks and for the quantification of rock textures (i.e., vesicle and crystal volume fraction, individual vesicle volumes and shapes, vesicle connectivity, vesicle volume distributions, permeability simulations etc.). We performed tomographic experiments on volcanic products erupted from different hazardous volcanic systems in Italy and around the world: Campi Flegrei, Stromboli, Etna (Southern Italy), Villarrica (Chile), Yasur and Ambrym (Vanuatu Islands). As an example, we used the results of these studies to constrain the dynamics of vesiculation and degassing in basaltic (Polacci et al., 2006; Burton et al., 2007; Colò et al., 2007; Andronico et al., 2008; Polacci et al., 2008a) and trachytic (Piochi et al., 2008) magmas. A better knowledge of how gas is transported and lost from magmas has led us in turn to draw new implications on the eruptive style of these active, hazardous volcanoes (Polacci et al., 2008b). Work in progress consists of optimizing our procedure by establishing a precise protocol that will enable us to quantitatively study the 3-D texture and composition of rocks in a statistically representative way. Future work will concentrate on the study of the spatial relations between phases (crystals, vesicles and glass) in rocks and their implications on the rheological properties of magmas and on the intensity of explosive activity at volcanoes. Andronico, D., R. A. Corsaro, A. Cristaldi, and M. Polacci (2008), Characterizing high energy explosive eruptions at Stromboli volcano using multidisciplinary data: An example from the 9 January 2005 explosion, J. Volcanol. Geotherm. Res., 176, 541-550. Burton, M. R., H. M. Mader, and M. Polacci (2007), The role of gas percolation in quiescent degassing of persistently active volcanoes, E. Planet. Sci. Lett., 264, 46-60. Colò, L., D. R. Baker, M. Polacci, and M. Ripepe (2007), Magma vesiculation and infrasonic activity in open conduit volcanoes, abstract presented at the AGU 2007 Fall meeting, 10-14 December, San Francisco, California, USA. Piochi, M., M. Polacci, G. De Astis, R. Zanetti, A. Mangiacapra, R. Vannucci, and D. Giordano (2008), Texture and composition of pumices and scoriae from the Campi Flegrei caldera (Italy): implications on the dynamics of explosive eruptions, G-cubed, doi:10.1029/2007GC001746. Polacci, M., D. R. Baker, L. Mancini, G. Tromba, F. Zanini (2006), Three-dimensional investigation of volcanic textures by X-ray microtomography and implications for conduit processes, Geophys. Res. Lett., 33, L13312, doi:10.1029/2006GL026241. Polacci, M., D. R. Baker, L. Bai, and L. Mancini (2008a), Large vesicles record pathways of degassing at basaltic volcanoes, Bull. Volcanol., 70, 1023-1029, doi:10.1007/s00445-007-0184-8. Polacci, M., D. R. Baker, L. Mancini, S. Favretto, and R. Hill (2008b), Vesiculation in magmas from Stromboli (Aeolian Archipelago, Italy) and implications for normal Strombolian activity and paroxysmal explosions in basaltic systems, J. Geophys. Res., doi:10.1029/2008JB005802

FAILURE OF A NEUTRINO-DRIVEN EXPLOSION AFTER CORE-COLLAPSE MAY LEAD TO A THERMONUCLEAR SUPERNOVA

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

Kushnir, Doron; Katz, Boaz, E-mail: kushnir@ias.edu

We demonstrate that ∼10 s after the core-collapse of a massive star, a thermonuclear explosion of the outer shells is possible for some (tuned) initial density and composition profiles, assuming that the neutrinos failed to explode the star. The explosion may lead to a successful supernova, as first suggested by Burbidge et al. We perform a series of one-dimensional (1D) calculations of collapsing massive stars with simplified initial density profiles (similar to the results of stellar evolution calculations) and various compositions (not similar to 1D stellar evolution calculations). We assume that the neutrinos escaped with a negligible effect on themore » outer layers, which inevitably collapse. As the shells collapse, they compress and heat up adiabatically, enhancing the rate of thermonuclear burning. In some cases, where significant shells of mixed helium and oxygen are present with pre-collapsed burning times of ≲100 s (≈10 times the free-fall time), a thermonuclear detonation wave is ignited, which unbinds the outer layers of the star, leading to a supernova. The energy released is small, ≲10{sup 50} erg, and negligible amounts of synthesized material (including {sup 56}Ni) are ejected, implying that these 1D simulations are unlikely to represent typical core-collapse supernovae. However, they do serve as a proof of concept that the core-collapse-induced thermonuclear explosions are possible, and more realistic two-dimensional and three-dimensional simulations are within current computational capabilities.« less

Effects of magnesium-based hydrogen storage materials on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant.

PubMed

Liu, Leili; Li, Jie; Zhang, Lingyao; Tian, Siyu

2018-01-15

MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 were prepared, and their structure and hydrogen storage properties were determined through X-ray photoelectron spectroscopy and thermal analyzer. The effects of MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant were subsequently studied. Results indicated that MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 can decrease the thermal decomposition peak temperature and increase the total released heat of decomposition. These compounds can improve the effect of thermal decomposition of the propellant. The burning rates of the propellant increased using Mg-based hydrogen storage materials as promoter. The burning rates of the propellant also increased using MgH 2 instead of Al in the propellant, but its explosive heat was not enlarged. Nonetheless, the combustion heat of MgH 2 was higher than that of Al. A possible mechanism was thus proposed. Copyright © 2017. Published by Elsevier B.V.

Persistent explosive activity at Stromboli investigated with OP-FTIR and SO2 cameras

NASA Astrophysics Data System (ADS)

Burton, M. R.; La Spina, A.; Sawyer, G. M.; Harris, A. J.

2012-12-01

Stromboli volcano in Italy exhibits what is perhaps one of the most well-known examples of cyclic activity, in the form of its regular explosions, which send a few m3 of material 100-200 m into the air every 10-20 minutes. Recent developments in measurements of volatile release from Stromboli using a series of novel approaches have allowed this cyclic behaviour to be examined in detail. In particular, the use of an automated OP-FTIR has revealed unprecedented detail in the dynamics of degassing from individual craters at the summit of Stromboli. Furthermore, the variations in composition of explosive degassing from Stromboli demonstrate a deep source ~2 km for the gas slugs which produce explosions at this volcano, in contrast to the commonly-held view that gas coalescence at shallow depth is responsible for the behaviour. The SO2 camera has revealed fascinating new details on the dynamics of degassing at Stromboli, and has allowed direct quantification of the amount of gas released during explosions and through quiescent degassing. The remarkable observation that 99% of degassing takes place quiescently, and that the explosions, whilst apparently more significant, are in fact a secondary process compared with the mass and energy involved in background, quiet processes. The new insight that the explosions are actually only a relatively minor aspect of the activity (in terms of mass and energy) actually makes the regularity of the cyclic explosive activity still more remarkable. In this paper we present a detailed overview of the state of the art of our understanding of cyclic explosive activity at Stromboli volcano from the perspective of recent advances in geochemical monitoring of the gas emissions. We also report initial results from a multidisciplinary campaign on Stromboli which utilised both OP-FTIR and SO2 camera techniques.

Application of paper spray ionization for explosives analysis.

PubMed

Tsai, Chia-Wei; Tipple, Christopher A; Yost, Richard A

2017-10-15

A desired feature in the analysis of explosives is to decrease the time of the entire analysis procedure, including sampling. A recently utilized ambient ionization technique, paper spray ionization (PSI), provides the possibility of combining sampling and ionization. However, an interesting phenomenon that occurs in generating negatively charged ions pose some challenges in applying PSI to explosives analysis. The goal of this work is to investigate the possible solutions for generating explosives ions in negative mode PSI. The analysis of 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) was performed. Several solvent systems with different surface tensions and additives were compared to determine their effect on the ionization of explosives. The solvents tested include tert-butanol, isopropanol, methanol, and acetonitrile. The additives tested were carbon tetrachloride and ammonium nitrate. Of the solvents tested, isopropanol yielded the best results. In addition, adding ammonium nitrate to the isopropanol enhanced the analyte signal. Experimentally determined limits of detection (LODs) as low as 0.06 ng for PETN, on paper, were observed with isopropanol and the addition of 0.4 mM ammonium nitrate as the spray solution. In addition, the explosive components of two plastic explosive samples, Composition 4 and Semtex, were successfully analyzed via surface sampling when using the developed method. The analysis of explosives using PSI-MS in negative ion mode was achieved. The addition of ammonium nitrate to isopropanol, in general, enhanced the analyte signal and yielded better ionization stability. Real-world explosive samples were analyzed, which demonstrates one of the potential applications of PSI-MS analysis. Copyright © 2017 John Wiley & Sons, Ltd.

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

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 cell lysis as a mechanism for the biogenesis of bacterial membrane vesicles and biofilms

PubMed Central

Turnbull, Lynne; Toyofuku, Masanori; Hynen, Amelia L.; Kurosawa, Masaharu; Pessi, Gabriella; Petty, Nicola K.; Osvath, Sarah R.; Cárcamo-Oyarce, Gerardo; Gloag, Erin S.; Shimoni, Raz; Omasits, Ulrich; Ito, Satoshi; Yap, Xinhui; Monahan, Leigh G.; Cavaliere, Rosalia; Ahrens, Christian H.; Charles, Ian G.; Nomura, Nobuhiko; Eberl, Leo; Whitchurch, Cynthia B.

2016-01-01

Many bacteria produce extracellular and surface-associated components such as membrane vesicles (MVs), extracellular DNA and moonlighting cytosolic proteins for which the biogenesis and export pathways are not fully understood. Here we show that the explosive cell lysis of a sub-population of cells accounts for the liberation of cytosolic content in Pseudomonas aeruginosa biofilms. Super-resolution microscopy reveals that explosive cell lysis also produces shattered membrane fragments that rapidly form MVs. A prophage endolysin encoded within the R- and F-pyocin gene cluster is essential for explosive cell lysis. Endolysin-deficient mutants are defective in MV production and biofilm development, consistent with a crucial role in the biogenesis of MVs and liberation of extracellular DNA and other biofilm matrix components. Our findings reveal that explosive cell lysis, mediated through the activity of a cryptic prophage endolysin, acts as a mechanism for the production of bacterial MVs. PMID:27075392

IMEC-9: The 9th Israel Materials Engineering Conference. Program & Abstracts

DTIC Science & Technology

1999-12-07

non- toxic , magnetite (FesC^) nanoparticles of very narrow size distribution in sizes ranging from approximately 20 nm up to 0.1 urn. The process for...Israel 17 Composites I Hall G Chair: R. Albalak 13:30 -13:50 Synthesis of Dense Oxide -Based In Situ Composites via Thermal Explosion/SHS...Tsionsky, Israel 16:00 -16:20 The Effect of Composition and Microstructure on the Corrosion Behavior of Magnesium- Aluminium Alloys P. Uzan, D. Eliezer

Apparatus and method for explosive bonding to edge of flyer plate

NASA Technical Reports Server (NTRS)

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

1991-01-01

The invention is an apparatus and a process for the explosive joining of a flyer plate and a base plate. The apparatus consists of a flyer plate positioned over a base plate. The flyer plate has a notch containing a filler material in intimate contact with the flyer plate. An adhesive means holds a ribbon explosive partially overlapping the notch in the flyer plate. A detonating means initiates the ribbon explosive that drives the flyer plate to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and effacing bonding, resulting in electron sharing linkups between the plates. An unbonded tab fractures at a base of the notch leaving a bond to an edge of the attached flyer plate.

Influence of nanomodification additives on the properties of multilayer composite coating obtained in laser surfacing

NASA Astrophysics Data System (ADS)

Cherepanov, A. N.; Orishich, A. M.; Ovcharenko, V. E.; Malikov, A. G.; Drozdov, V. O.; Pshenichnikov, A. P.

2017-10-01

The paper presents the results of numerical and experimental studies of the process of obtaining a permanent joint of two plates of heterogeneous metals that cannot be welded in the usual way: alloy Grade 4 and steel AISI 321 using a laser beam and an intermediate composite insert. The composite insert was obtained by explosion welding of four thin plates of titanium (Grade 4), niobium, copper, and steel (AISI 321). The insert was placed between the welded plates of titanium and steel, and the steel plate was welded with the steel part of the insert, and the titanium plate was welded with the titanium part of the insert. The plates were welded using a CO2 laser. The connection of metals with the help of explosion is carried out without their melting, so the formation of the brittle intermetallics does not occur in most cases. This ensures the greatest strength of the joints as compared to the joints obtained by other welding methods. To analyze the distribution of thermal fields in the composite insert and welded plates, a numerical study was conducted of the laser welding of steel and titanium plates with the corresponding parts of the insert. The purpose of the study was to determine the rational parameters of welding (laser beam power, speed of its movement, size and position of the focal spot), at which there was no complete melting of the steel and titanium parts of the insert during through penetration of the welded plates. The experimental part of the work is devoted to analysis of formation of the internal boundaries and microstructure of the composite insert and the strength of the permanent joint. It is shown that as a result of the explosion welding, weld seams of different wavelike configuration are formed. The most pronounced wavelike boundary is observed in the steel-copper connection, since these materials have a face-centered cubic lattice and are easily subjected to plastic deformation. At the contact boundaries of the plates, transition diffusion zones with different widths (from 5 to 40 μm) and element concentrations are formed. The hardness in the boundary diffusion zones is higher than in the connected metals, which is due to the diffusion interaction of the materials adjacent to each other. It has been established that the tensile strength of the composite insert is comparable to the maximum strength of Grade 4 alloy (456-511 MPa), and the failure in most cases occurred over the least durable component of the composite material, which is the copper plate, whose strength was significantly increased by cold hardening during explosion welding and diffusion of elements of the contacting plates.

Energetic Materials - Technology, Manufacturing and Processing, 27th International Annual Conference of ICT June 25 - June 28, 1996 Karisruhe, Federal Republic of Germany.

DTIC Science & Technology

1997-02-01

PROPELLANTS WITH VARYING COMPOSITION L.F. Dimaranan, I. Lee, F.E. Hudson III V12 A COMBUSTION MODEL FOR AN/HTPB-IPDI COMPOSITE SOLID PROPELLANTS P... COMPOSITE PROPELLANTS WITH A LOW PRESSURE EXPONENT SUITABLE FOR NOZZLELESS BOOSTER MOTORS G.J. van Zyl V21 PROPERTIES OF AN AND PSAN/GAP-PROPELLANTS K...APPLICATION B.N. Kondrikov SENSITIVITY TO PROJECTILE IMPACT OF PRE-HEATED EXPLOSIVE COMPOSITIONS H.Cherin, D. Lemoine, L. Gautier VULNERABILITY TESTING OF

Time-Dependent Moment Tensors of the First Four Source Physics Experiments (SPE) Explosions

NASA Astrophysics Data System (ADS)

Yang, X.

2015-12-01

We use mainly vertical-component geophone data within 2 km from the epicenter to invert for time-dependent moment tensors of the first four SPE explosions: SPE-1, SPE-2, SPE-3 and SPE-4Prime. We employ a one-dimensional (1D) velocity model developed from P- and Rg-wave travel times for Green's function calculations. The attenuation structure of the model is developed from P- and Rg-wave amplitudes. We select data for the inversion based on the criterion that they show consistent travel times and amplitude behavior as those predicted by the 1D model. Due to limited azimuthal coverage of the sources and the mostly vertical-component-only nature of the dataset, only long-period, diagonal components of the moment tensors are well constrained. Nevertheless, the moment tensors, particularly their isotropic components, provide reasonable estimates of the long-period source amplitudes as well as estimates of corner frequencies, albeit with larger uncertainties. The estimated corner frequencies, however, are consistent with estimates from ratios of seismogram spectra from different explosions. These long-period source amplitudes and corner frequencies cannot be fit by classical P-wave explosion source models. The results motivate the development of new P-wave source models suitable for these chemical explosions. To that end, we fit inverted moment-tensor spectra by modifying the classical explosion model using regressions of estimated source parameters. Although the number of data points used in the regression is small, the approach suggests a way for the new-model development when more data are collected.

Progenitor-dependent Explosion Dynamics in Self-consistent, Axisymmetric Simulations of Neutrino-driven Core-collapse Supernovae

NASA Astrophysics Data System (ADS)

Summa, Alexander; Hanke, Florian; Janka, Hans-Thomas; Melson, Tobias; Marek, Andreas; Müller, Bernhard

2016-07-01

We present self-consistent, axisymmetric core-collapse supernova simulations performed with the Prometheus-Vertex code for 18 pre-supernova models in the range of 11-28 M ⊙, including progenitors recently investigated by other groups. All models develop explosions, but depending on the progenitor structure, they can be divided into two classes. With a steep density decline at the Si/Si-O interface, the arrival of this interface at the shock front leads to a sudden drop of the mass-accretion rate, triggering a rapid approach to explosion. With a more gradually decreasing accretion rate, it takes longer for the neutrino heating to overcome the accretion ram pressure and explosions set in later. Early explosions are facilitated by high mass-accretion rates after bounce and correspondingly high neutrino luminosities combined with a pronounced drop of the accretion rate and ram pressure at the Si/Si-O interface. Because of rapidly shrinking neutron star radii and receding shock fronts after the passage through their maxima, our models exhibit short advection timescales, which favor the efficient growth of the standing accretion-shock instability. The latter plays a supportive role at least for the initiation of the re-expansion of the stalled shock before runaway. Taking into account the effects of turbulent pressure in the gain layer, we derive a generalized condition for the critical neutrino luminosity that captures the explosion behavior of all models very well. We validate the robustness of our findings by testing the influence of stochasticity, numerical resolution, and approximations in some aspects of the microphysics.

PROGENITOR-DEPENDENT EXPLOSION DYNAMICS IN SELF-CONSISTENT, AXISYMMETRIC SIMULATIONS OF NEUTRINO-DRIVEN CORE-COLLAPSE SUPERNOVAE

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

Summa, Alexander; Hanke, Florian; Janka, Hans-Thomas

We present self-consistent, axisymmetric core-collapse supernova simulations performed with the Prometheus-Vertex code for 18 pre-supernova models in the range of 11–28 M {sub ⊙}, including progenitors recently investigated by other groups. All models develop explosions, but depending on the progenitor structure, they can be divided into two classes. With a steep density decline at the Si/Si–O interface, the arrival of this interface at the shock front leads to a sudden drop of the mass-accretion rate, triggering a rapid approach to explosion. With a more gradually decreasing accretion rate, it takes longer for the neutrino heating to overcome the accretion rammore » pressure and explosions set in later. Early explosions are facilitated by high mass-accretion rates after bounce and correspondingly high neutrino luminosities combined with a pronounced drop of the accretion rate and ram pressure at the Si/Si–O interface. Because of rapidly shrinking neutron star radii and receding shock fronts after the passage through their maxima, our models exhibit short advection timescales, which favor the efficient growth of the standing accretion-shock instability. The latter plays a supportive role at least for the initiation of the re-expansion of the stalled shock before runaway. Taking into account the effects of turbulent pressure in the gain layer, we derive a generalized condition for the critical neutrino luminosity that captures the explosion behavior of all models very well. We validate the robustness of our findings by testing the influence of stochasticity, numerical resolution, and approximations in some aspects of the microphysics.« less

A Sulfur Trigger for the 2017 Phreatomagmatic Eruption of Poás Volcano, Costa Rica? Insights from MultiGAS and Drone-based Gas Monitoring

NASA Astrophysics Data System (ADS)

de Moor, M. J.; Aiuppa, A.; Avard, G.; Diaz, J. A.; Corrales, E.; Rüdiger, J.; D´Arcy, F.; Fischer, T. P.; Stix, J.; Alan, A.

2017-12-01

In April 2017 Poás volcano entered its first magmatic eruption period of the 21st century. The initial explosive blasts produced eruption columns up to 4 km in height, destroyed the pre-existing dome that was emplaced during the last magmatic eruption in the 1950s, and showered the tourist observation deck with bombs. Over the following months, the hyperacid crater lake dried out and a transition from phreatomagmatic to strombolian activity was observed. Two vents now dominate the activity. The main vent (old dome site) produces gas, ash, and scoria. A second vent is located in the dried-out lake bed and produces a peculiar canary-yellow gas plume. A fixed MultiGAS instrument installed in the crater bottom recorded large changes in gas composition prior to the explosive eruptions. The station recorded a dramatic increase in SO2/CO2 from an average of 0.04 for March 2017 to an average of 7.4 the day before the first explosive eruption that occurred at 18:30 on 12 April. A simultaneous rapid decrease in H2S/SO2 from 2.7 to <0.01 was observed prior to the eruptions. The MultiGAS station stopped transmitting data after 2 days of explosive eruptions. We since developed new methods for measuring gas compositions and SO2 fluxes using drones, allowing continued gas monitoring despite dangerous conditions. Extremely high SO2/CO2 of 33 was measured with drone-based miniaturized MultiGAS ("miniGAS") in May 2017, and the ratio has since dropped to 3, which are more typical values of high temperature magmatic gases at Poás. The SO2 flux from Poás was at record low levels (< 5 T/d) in late 2016 and early 2017. Drone-based SO2 DOAS ("DROAS") measurements indicate high SO2 fluxes from Poas of >2000 T/d since the explosive eruptions, indicating a strong magmatic source and open conduits. We attribute the unusually S-rich gas compositions observed at Poás prior to and during the initial eruptions to combustion of previously deposited hydrothermal sulfur. The very low gas flux from the system prior to the explosive eruptions suggests that this sulfur may have played a role in hydrothermal sealing, leading to pressurization of the magmatic-hydrothermal system and ultimately triggering phreatomagmatic eruptions and "top down" remobilization of previously emplaced magma.

Magmatic Ascent and Eruption Processes on Mercury

NASA Astrophysics Data System (ADS)

Head, J. W.; Wilson, L.

2018-05-01

MESSENGER volcanic landform data and information on crustal composition allow us to model the generation, ascent, and eruption of magma; Mercury explosive and effusive eruption processes differ significantly from other terrestrial planetary bodies.

Investigation on Explosive Welding of Zr53Cu35Al12 Bulk Metallic Glass with Crystalline Copper

NASA Astrophysics Data System (ADS)

Feng, Jianrui; Chen, Pengwan; Zhou, Qiang

2018-05-01

A Zr53Cu35Al12 bulk metallic glass (BMG) was welded to a crystalline Cu using explosive welding technique. The morphology and the composition of the composite were characterized using optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy and transmission electron microscopy. The investigation indicated that the BMG and Cu were tightly joined together without visible defects, and a thin diffusion layer appeared at the interface. The captured jet at the end of the welding region mostly comes from the Cu side. Amorphous and partially crystallized structures have been observed within the diffusion layer, but the BMG in close proximity to the interface still retains its amorphous state. Nanoindentation tests reveal that the interface exhibits an increment in hardness compared with the matrix on both sides.

Mathematical tool from corn stover TGA to determine its composition.

PubMed

Freda, Cesare; Zimbardi, Francesco; Nanna, Francesco; Viola, Egidio

2012-08-01

Corn stover was treated by steam explosion process at four different temperatures. A fraction of the four exploded matters was extracted by water. The eight samples (four from steam explosion and four from water extraction of exploded matters) were analysed by wet chemical way to quantify the amount of cellulose, hemicellulose and lignin. Thermogravimetric analysis in air atmosphere was executed on the eight samples. A mathematical tool was developed, using TGA data, to determine the composition of corn stover in terms of cellulose, hemicellulose and lignin. It uses the biomass degradation temperature as multiple linear function of the cellulose, hemicellulose and lignin content of the biomass with interactive terms. The mathematical tool predicted cellulose, hemicellulose and lignin contents with average absolute errors of 1.69, 5.59 and 0.74 %, respectively, compared to the wet chemical method.

ANTHROPOMETRIC CHARACTERISTICS AND FUNCTIONAL CAPACITY OF ELITE ROWERS AND HANDBALL PLAYERS.

PubMed

Karaba Jakovljevic, Dea; Jovanovic, Gordana; Eric, Mirela; Klasnja, Aleksandar; Slavic, Danijel; Lukac, Damir

2016-09-01

Anthropometric and anaerobic profile of elite athletes are fundamental for the assessment of their respective performance. The present study was designed to evaluate the anthro- pornetric parameters, body composition and anaerobic characteristics of elite male handball players and rowers, and to compare them in relation to specific sport demands. The study group consisted of 41 elite national level athletes: 20 handball players (aged 23.7±3.72) and 21 rowers (aged 19.7±2.84). Anthropometric characteristics (body mass, body height, skinfold thickness, body circumferences), and body fat mass were evaluated, and Wingate anaerobic test for anaerobic power assessment Iwas applied. The significant differences were noted in chest-upper arm, waist and hip circumferences, and supraspinal and calf skinfolds between the two investigated groups. Rowers showed higher values of fat body mass (13.2±3.76 vs. 10.7±3.76%), but lower body mass index (22.0±1,92 vs. 25.7?2.31 kg/in12) compared to handball players. When analyzing the Wingate test parameters, significantly higher values of absolute anaerobic power (786±127 vs. 691±140 W), absolute explosive power in the handball players compared to the rowers were recorded ( 18±26.3 vs. 105±27.8 W/s), whi le rowers achieved higher relative anaerobic capacity (192±3 1.2 vs. 177±E20.8 J/ kg). Specific body composition and anthropometri- cal assessment as a part of morphological analysis should complement physiological profile of elite athletes. The analysis of the anaerobic performance shows that the handball players have greater alactic anaerobic and explosive power component, compared to the rowers in whom the anaerobic endurance and specific training have the greatest effect on the consumption of dominant metabolic substrate during the race.

Chemical sensing system for classification of minelike objects by explosives detection

NASA Astrophysics Data System (ADS)

Chambers, William B.; Rodacy, Philip J.; Jones, Edwin E.; Gomez, Bernard J.; Woodfin, Ronald L.

1998-09-01

Sandia National Laboratories has conducted research in chemical sensing and analysis of explosives for many years. Recently, that experience has been directed towards detecting mines and unexploded ordnance (UXO) by sensing the low-level explosive signatures associated with these objects. Our focus has been on the classification of UXO in shallow water and anti-personnel/anti tank mines on land. The objective of this work is to develop a field portable chemical sensing system which can be used to examine mine-like objects (MLO) to determine whether there are explosive molecules associated with the MLO. Two sampling subsystems have been designed, one for water collection and one for soil/vapor sampling. The water sampler utilizes a flow-through chemical adsorbent canister to extract and concentrate the explosive molecules. Explosive molecules are thermally desorbed from the concentrator and trapped in a focusing stage for rapid desorption into an ion-mobility spectrometer (IMS). We will describe a prototype system which consists of a sampler, concentrator-focuser, and detector. The soil sampler employs a light-weight probe for extracting and concentrating explosive vapor from the soil in the vicinity of an MLO. The chemical sensing system is capable of sub-part-per-billion detection of TNT and related explosive munition compounds. We will present the results of field and laboratory tests on buried landmines, which demonstrate our ability to detect the explosive signatures associated with these objects.

Explosive eruptions triggered by rockfalls at Kīlauea volcano, Hawaii

USGS Publications Warehouse

Orr, Tim R.; Thelen, Weston A.; Patrick, Matthew R.; Swanson, Donald A.; Wilson, David C.

2012-01-01

Ongoing eruptive activity at Kīlauea volcano’s (Hawai‘i) summit has been controlled in part by the evolution of its vent from a 35-m-diameter opening into a collapse crater 150 m across. Geologic observations, in particular from a network of webcams, have provided an unprecedented look at collapse crater development, lava lake dynamics, and shallow outgassing processes. These observations show unequivocally that the hundreds of transient outgassing bursts and weak explosive eruptions that have punctuated the vent’s otherwise nearly steady-state behavior, and that are associated with composite seismic events, were triggered by rockfalls from the vent walls onto the top of the lava column. While the process by which rockfalls drive the explosive bursts is not fully understood, we believe that it is initiated by the generation of a rebound splash, or Worthington jet, which then undergoes fragmentation. The external triggering of low-energy outgassing events by rockfalls represents a new class of small transient explosive eruptions.

Effects of acid impregnated steam explosion process on xylose recovery and enzymatic conversion of cellulose in corncob.

PubMed

Fan, Xiaoguang; Cheng, Gang; Zhang, Hongjia; Li, Menghua; Wang, Shizeng; Yuan, Qipeng

2014-12-19

Corncob residue is a cellulose-rich byproduct obtained from industrial xylose production via dilute acid hydrolysis processes. Enzymatic hydrolysis of cellulose in acid hydrolysis residue of corncob (AHRC) is often less efficient without further pretreatment. In this work, the process characteristics of acid impregnated steam explosion were studied in conjunction with a dilute acid process, and their effects on physiochemical changes and enzymatic saccharification of corncob residue were compared. With the acid impregnated steam explosion process, both higher xylose recovery and higher cellulose conversion were obtained. The maximum conversion of cellulose in acid impregnated steam explosion residue of corncob (ASERC) reached 85.3%, which was 1.6 times higher than that of AHRC. Biomass compositional analysis showed similar cellulose and lignin content in ASERC and AHRC. XRD analysis demonstrated comparable crystallinity of ASERC and AHRC. The improved enzymatic hydrolysis efficiency was attributed to higher porosity in ASERC, measured by mercury porosimetry. Copyright © 2014 Elsevier Ltd. All rights reserved.

A mesoscopic reaction rate model for shock initiation of multi-component PBX explosives.

PubMed

Liu, Y R; Duan, Z P; Zhang, Z Y; Ou, Z C; Huang, F L

2016-11-05

The primary goal of this research is to develop a three-term mesoscopic reaction rate model that consists of a hot-spot ignition, a low-pressure slow burning and a high-pressure fast reaction terms for shock initiation of multi-component Plastic Bonded Explosives (PBX). Thereinto, based on the DZK hot-spot model for a single-component PBX explosive, the hot-spot ignition term as well as its reaction rate is obtained through a "mixing rule" of the explosive components; new expressions for both the low-pressure slow burning term and the high-pressure fast reaction term are also obtained by establishing the relationships between the reaction rate of the multi-component PBX explosive and that of its explosive components, based on the low-pressure slow burning term and the high-pressure fast reaction term of a mesoscopic reaction rate model. Furthermore, for verification, the new reaction rate model is incorporated into the DYNA2D code to simulate numerically the shock initiation process of the PBXC03 and the PBXC10 multi-component PBX explosives, and the numerical results of the pressure histories at different Lagrange locations in explosive are found to be in good agreements with previous experimental data. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Minimizing masses in explosively driven two-shockwave physics applications

NASA Astrophysics Data System (ADS)

Buttler, William; Cherne, Frank; Furlanetto, Michael; Payton, Jeremy; Stone, Joseph; Tabaka, Leonard; Vincent, Samuel

2015-06-01

We have experimentally investigated different two-shockwave high-explosives (HE) physics package designs to maximize the variability of the second shockwave peak stress, while minimizing the total HE load of the physics tool. A critical requirement is to also have a large radial diameter of the second shockwave to maintain its value as an HE driven two-shockwave drive. We have previously shown that we could vary the peak-stress of the second-shockwave with a 76 mm diameter HE lens driving different composite boosters of PBX 9501 and TNT. Here we report on our results with a 56- and 50-mm diameter HE lens driving Baritol. The results indicate that the 56-mm diameter HE lens works well, as does the Baritol, giving total HE loads of about 250 mg TNT equivalent explosives.

The role of electro-explosion alloying with titanium diboride and treatment with pulsed electron beam in the surface modification of VT6 alloy

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

Konovalov, Sergey, E-mail: konovserg@gmail.com; Gromov, Victor, E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatyana

The paper presents the results of the investigation of VT6 titanium alloy subjected to electro-explosion alloying with TiB{sub 2} and irradiation with pulsed electron beam. It was established that electro-explosion alloying resulted in a high level of roughness of the surface layer with high adhesion of the modified layer and matrix. Further irradiation of the material with electron beam resulted in the smoothing of the surface of alloying and formation of a porous structure with various scale levels in the surface layer. It was also established that the energetic exposure causes the formation of a gradient structure with a changingmore » elemental composition along the direction from the surface of alloying.« less

Fabrication and Characteristics of Al/PTFE Multilayers and Application in Micro-initiator

NASA Astrophysics Data System (ADS)

Zhang, Yuxin; Jiang, Hongchuan; Zhao, Xiaohui; Zhang, Wanli; Li, Yanrong

2017-12-01

In this paper, a micro-initiator was designed and fabricated by integrating Al/PTFE multilayers with a Cu film bridge. The regularity layer structure and interface composition of Al/PTFE multilayers was analysed by transmission electron microscope and X-ray photoelectron spectroscopy, respectively. The heat release reaction in Al/PTFE multilayers can be triggered with reaction temperature of 430 °C, and the overall heat of reaction is 3192 J/g. Al/PTFE multilayers with bilayer thickness of 200 nm was alternately deposited on a Cu film bridge to improve the electric explosion performances. Compared to Cu film bridge, the Al/PTFE/Cu integrated film bridge exhibits improved performances with longer explosion duration time, more violent explosion phenomenon and larger quantities of ejected product particles.

Influence of Dense Inert Additives (W and Pb) on Detonation Conditions and Regime of Condensed Explosives

NASA Astrophysics Data System (ADS)

Imkhovik, Nikolay A.

2010-10-01

Results of experimental and theoretical studies of the unusual detonation properties of mixtures of high explosives (HEs) with high-density inert additives W and Pb were analyzed and systematized. Typical examples of the nonideal detonation of composite explosives for which the measured detonation pressure is substantially lower and the detonation velocity is higher than the values calculated within the framework of the hydrodynamic model, with the specific heat ratio for the detonation products of ∼6-8, are presented. Mechanisms of formation of anomalous pressure and mass velocity profiles, which explain the correlation between the Chapman-Jouguet pressure for HE-W and HE-Pb mixtures, the velocity of the free surface of duralumin target, and the depth of the dent imprinted in steel witness plates, are described.

Eruptive mechanism at Volcán de Colima: Interpreting transitions between styles

NASA Astrophysics Data System (ADS)

Varley, N.; James, M. R.; Hutchison, W.; Arámbula, R.; Reyes, G.

2013-05-01

In January 2013 eruptions resumed at Volcán de Colima, the previous activity having ceased in June 2011. This period represented the quietest the volcano has been since before the previous episode commenced in 1998. The new eruptive episode is showing differences compared to the 1998-2011 period, which are presenting a challenge to interpret. Lower gases fluxes coupled with lower fumaroles temperatures are consistent with the decreasing trend of volatile-contents but the two larger Vulcanian eruptions in January produced pyroclastic density currents with a greater degree of fragmentation than previous events. A dome has been growing within the newly formed crater within the previous dome. The 1998-2011 eruption included five periods of effusive activity, with little variation in composition. Domes grew with effusion rates covering more than 2 orders of magnitude. Both explosive and effusive activity was centred at multiple locations within the summit crater. The SO2 flux showed a general declining trend throughout this period and 2005 included the largest pyroclastic flows witnessed since the last Plinian eruption in 1913. Swarms of small amplitude long period events were detected prior to each larger eruption, these have been again witnessed in 2013. The characteristics of the swarms is being compared, the generation of events being related to brittle fracturing along the conduit margin. The episode terminated in June 2011 with an explosion which removed the upper portion of the most recent and extended period of dome growth, which was at a very slow rate from January 2007. Automated 3D computer vision reconstruction techniques (structure-from-motion and multi-view stereo, SfM-MVS) have permitted the estimation of dome volumes from 1 m resolution digital elevation models. A small decrease in volume (0.4×105 m3) was detected prior to the explosion, which was related to the formation of steps in the dome surface, related to localized zones of weakness. For the explosion, the region of greatest volume loss was observed to be not coincident with the assumed location of the conduit, suggesting and that heterogeneity within the dome was important during the June explosion. Analysis of thermal images taken during flights has permitted the detailed modelling of the dome emplacement processes. The onset of rockfalls on the W side once it reached the crater rim provoked a change in emplacement style from endogenic to exogenic. Monitoring the activity during the recent eruption has produced a wealth of data making it an excellent case study for modelling transitions between different regimes and the generating mechanism for Vulcanian explosions.

The application of single particle aerosol mass spectrometry for the detection and identification of high explosives and chemical warfare agents

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

Martin, Audrey Noreen

2006-01-01

Single Particle Aerosol Mass Spectrometry (SPAMS) was evaluated as a real-time detection technique for single particles of high explosives. Dual-polarity time-of-flight mass spectra were obtained for samples of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN); peaks indicative of each compound were identified. Composite explosives, Comp B, Semtex 1A, and Semtex 1H were also analyzed, and peaks due to the explosive components of each sample were present in each spectrum. Mass spectral variability with laser fluence is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle (~1 pg) without the need formore » consumables is demonstrated. SPAMS was also applied to the detection of Chemical Warfare Agent (CWA) simulants in the liquid and vapor phases. Liquid simulants for sarin, cyclosarin, tabun, and VX were analyzed; peaks indicative of each simulant were identified. Vapor phase CWA simulants were adsorbed onto alumina, silica, Zeolite, activated carbon, and metal powders which were directly analyzed using SPAMS. The use of metal powders as adsorbent materials was especially useful in the analysis of triethyl phosphate (TEP), a VX stimulant, which was undetectable using SPAMS in the liquid phase. The capability of SPAMS to detect high explosives and CWA simulants using one set of operational conditions is established.« less

Making molecular balloons in laser-induced explosive boiling of polymer solutions.

PubMed

Leveugle, Elodie; Sellinger, Aaron; Fitz-Gerald, James M; Zhigilei, Leonid V

2007-05-25

The effect of the dynamic molecular rearrangements leading to compositional segregation is revealed in coarse-grained molecular dynamics simulations of short pulse laser interaction with a polymer solution in a volatile matrix. An internal release of matrix vapor at the onset of the explosive boiling of the overheated liquid is capable of pushing polymer molecules to the outskirts of a transient bubble, forming a polymer-rich surface layer enclosing the volatile matrix material. The results explain unexpected "deflated balloon" structures observed in films deposited by the matrix-assisted pulsed laser evaporation technique.

Pyroclastic Activity at Home Plate in Gusev Crater, Mars

NASA Technical Reports Server (NTRS)

Squyres, S. W.; Aharonson, O.; Clark, B. S.; Cohen, B.; Crumpler, L.; deSouza, P. A.; Farrand, W. H.; Gellert, R.; Grant, J.; Grotzinger, J. P.;

Pyroclastic activity at home plate in Gusev crater, Mars

USGS Publications Warehouse

Squyres, S. W.; Aharonson, O.; Clark, B. C.; Cohen, B. A.; Crumpler, L.; de Souza, P.A.; Farrand, W. H.; Gellert, Ralf; Grant, J.; Grotzinger, J.P.; Haldemann, A.F.C.; Johnson, J. R.; Klingelhofer, G.; Lewis, K.W.; Li, R.; McCoy, T.; McEwen, A.S.; McSween, H.Y.; Ming, D. W.; Moore, Johnnie N.; Morris, R.V.; Parker, T.J.; Rice, J. W.; Ruff, S.; Schmidt, M.; Schroder, C.; Soderblom, L.A.; Yen, A.

2007-01-01

Home Plate is a layered plateau in Gusev crater on Mars. It is composed of clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile elements. A coarse-grained lower unit lies under a finer-grained upper unit. Textural observations indicate that the lower strata were emplaced in an explosive event, and geochemical considerations favor an explosive volcanic origin over an impact origin. The lower unit likely represents accumulation of pyroclastic materials, whereas the upper unit may represent eolian reworking of the same pyroclastic materials.

Decompression experiments identify kinetic controls on explosive silicic eruptions

USGS Publications Warehouse

Mangan, M.T.; Sisson, T.W.; Hankins, W.B.

2004-01-01

Eruption intensity is largely controlled by decompression-induced release of water-rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (??Pcritical) triggering gas bubble nucleation. High temperature and pressure decompression experiments using rhyolite and dacite melt reveal compositionally-dependent differences in the ??Pcritical of degassing that may explain why rhyolites have fueled some of the most explosive eruptions on record.

Dead Star Rumbles

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Composite of Supernova Remnant Cassiopeia A This Spitzer Space Telescope composite shows the supernova remnant Cassiopeia A (white ball) and surrounding clouds of dust (gray, orange and blue). It consists of two processed images taken one year apart. Dust features that have not changed over time appear gray, while those that have changed are colored blue or orange. Blue represents an earlier time and orange, a later time.

These observations illustrate that a blast of light from Cassiopeia A is waltzing outward through the dusty skies. This dance, called an 'infrared echo,' began when the remnant erupted about 50 years ago.

Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion 325 years ago. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died. This remnant is located 10,000 light-years away in the northern constellation Cassiopeia.

An infrared echo is created when a star explodes or erupts, flashing light into surrounding clumps of dust. As the light zips through the dust clumps, it heats them up, causing them to glow successively in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light. This apparent motion can be seen here by the shift in colored dust clumps.

Echoes are distinct from supernova shockwaves, which are made up material that is swept up and hurled outward by exploding stars.

This infrared echo is the largest ever seen, stretching more than 50 light-years away from Cassiopeia A. If viewed from Earth, the entire movie frame would take up the same amount of space as two full moons.

Hints of an older infrared echo from Cassiopeia A's supernova explosion hundreds of years ago can also be seen.

The earlier Spitzer image was taken on November 30, 2003, and the later, on December 2, 2004.

Simulation of the detonation process of an ammonium nitrate based emulsion explosive using the Lee-Tarver reactive flow model

NASA Astrophysics Data System (ADS)

Ribeiro, Jose; Silva, Cristovao; Mendes, Ricardo; Plaksin, Igor; Campos, Jose

2011-06-01

The use of emulsion explosives [EEx] for processing materials (compaction, welding and forming) requires the ability to perform detailed simulations of its detonation process [DP]. Detailed numerical simulations of the DP of this kind of explosives, characterized by having a finite reaction zone thickness, are thought to be suitable performed using the Lee-Tarver reactive flow model. In this work a real coded genetic algorithm methodology was used to estimate the 15 parameters of the reaction rate equation [RRE] of that model for a particular EEx. This methodology allows, in a single optimization procedure, using only one experimental result and without the need of any starting solution, to seek for the 15 parameters of the RRE that fit the numerical to the experimental results. Mass averaging and the Plate-Gap Model have been used for the determination of the shock data used in the unreacted explosive JWL EoS assessment and the thermochemical code THOR retrieved the data used in the detonation products JWL EoS assessment. The obtained parameters allow a good description of the experimental data and show some peculiarities arising from the intrinsic nature of this kind of composite explosive.

Velocity Model Using the Large-N Seismic Array from the Source Physics Experiment (SPE)

NASA Astrophysics Data System (ADS)

Chen, T.; Snelson, C. M.

2016-12-01

The Source Physics Experiment (SPE) is a multi-institutional, multi-disciplinary project that consists of a series of chemical explosions conducted at the Nevada National Security Site (NNSS). The goal of SPE is to understand the complicated effect of geological structures on seismic wave propagation and source energy partitioning, develop and validate physics-based modeling, and ultimately better monitor low-yield nuclear explosions. A Large-N seismic array was deployed at the SPE site to image the full 3D wavefield from the most recent SPE-5 explosion on April 26, 2016. The Large-N seismic array consists of 996 geophones (half three-component and half vertical-component sensors), and operated for one month, recording the SPE-5 shot, ambient noise, and additional controlled-sources (a large hammer). This study uses Large-N array recordings of the SPE-5 chemical explosion to develop high resolution images of local geologic structures. We analyze different phases of recorded seismic data and construct a velocity model based on arrival times. The results of this study will be incorporated into the large modeling and simulation efforts as ground-truth further validating the models.

Detonating apparatus

DOEpatents

Johnston, Lawrence H.

1976-01-01

1. Apparatus for detonation of high explosive in uniform timing comprising in combination, an outer case, spark gap electrodes insulatedly supported in spaced relationship within said case to form a spark gap, high explosive of the class consisting of pentaerythritol tetranitrate and trimethylene trinitramine substantially free from material sensitive to detonation by impact compressed in surrounding relation to said electrodes including said spark gap under a pressure from about 100 psi to about 500 psi, said spark gap with said compressed explosive therein requiring at least 1000 volts for sparking, and means for impressing at least 1000 volts on said spark gap.

Scene of Multiple Explosions

NASA Image and Video Library

2007-03-07

This composite image NASA Galaxy Evolution Explorer shows Z Camelopardalis, or Z Cam, a double-star system featuring a collapsed, dead star, called a white dwarf, and a companion star, as well as a ghostly shell around the system.

Volcanism on Mercury

NASA Astrophysics Data System (ADS)

Rothery, David A.

2017-12-01

Mercury has no recognized tracts of intact primary crust analogous to lunar highland crust, probably because Mercury's iron-poor magma ocean was insufficiently dense to enable crystallized silicates to float. Its surface is accepted to consist mostly of multiple generations of lavas, rather like terrestrial "large igneous provinces" or LIPs, emplaced in greatest volumes prior to about 3.5 Ga. Subsequently, erupted volumes decreased, and became largely confined to impact craters. Plains younger than about 3.7 Ga are scarred by so few impact craters that they are mapped as "smooth plains." Older plains are termed "intercrater plains." There is no consensus on whether plains with characteristics intermediate between smooth and intercrater plains can be consistently mapped (as "intermediate plains"). The volcanic nature of Mercury's smooth plains was ambiguous on images returned by the first mission to Mercury, Mariner 10 (three flybys in 1974–1975. Better imaging by MESSENGER (in orbit 2011–2015) removed doubt by documenting innumerable ghost craters and wrinkle ridges. Vents are obscure, as is normal in LIPs, but there are good examples of streamlined islands showing the passage of fast-flowing, low-viscosity lava. The causes of mantle partial melting necessary to supply Mercury's eruptions are unclear, but secular cooling of a small, one-plate planet is expected to lead to the decrease in volcanic activity that we observe. Factors include loss of primordial heat and declining rate of radiogenic heat production, and closure of pathways by planetary thermal contraction. Lava compositions resemble komatiites but with low iron content. Regional variations may reflect lateral and vertical heterogeneities in the mantle, or different degrees of partial melting. The cessation of effusive volcanism on Mercury is hard to date because the youngest areas are small. However, it probably continued until about 1 Ga. That was not the end of volcanism on the planet. MESSENGER images show >100 "pits," which are noncircular holes up to tens of km across and up to about 4 km deep. Many are surrounded by spectrally red deposits, with faint outer edges many tens of km from the pit, interpreted as ejecta from explosive eruptions. Some pits have complex floors, suggesting vent migration. Explosive eruptions require violent gas expansion. This could be either a magmatic volatile expanding near the top of a magma conduit, or a result from heating of a crustal/near-surface volatile by approaching magma. Mercury's crust is surprisingly rich in volatiles, of which the one likely to be of most importance in driving the explosive eruptions is sulfur. We do not know when explosive volcanism began on Mercury. Cross-cutting relationships suggest that some explosion pits are considerably less than 1 Ga old, though most could easily be older than 3 Ga. They characteristically occur associated with structures inside impact craters, and while some pits have no discernible "red spot" surrounding them (perhaps because over time it has faded into the background), there is no known example of partial burial of a red spot by a smooth plains unit. Thus, there seems to have been a change in eruptive style, with (small volume) explosions supplanting (large volume) effusive events.

A Physical Basis for M s-Yield Scaling in Hard Rock and Implications for Late-Time Damage of the Source Medium

DOE PAGES

Patton, Howard John

2016-04-11

Surface wave magnitude M s for a compilation of 72 nuclear tests detonated in hard rock media for which yields and burial depths have been reported in the literature is shown to scale with yield W as a + b × log[W], where a = 2.50 ± 0.08 and b = 0.80 ± 0.05. While the exponent b is consistent with an M s scaling model for fully coupled, normal containment-depth explosions, the intercept a is offset 0.45 magnitude units lower than the model. The cause of offset is important to understand in terms of the explosion source. Hard rockmore » explosions conducted in extensional and compressional stress regimes show similar offsets, an indication that the tectonic setting in which an explosion occurs plays no role causing the offset. The scaling model accounts for the effects of source medium material properties on the generation of 20-s period Rayleigh wave amplitudes. Aided by thorough characterizations of the explosion and tectonic release sources, an extensive analysis of the 1963 October 26 Shoal nuclear test detonated in granite 27 miles southeast of Fallon NV shows that the offset is consistent with the predictions of a material damage source model related to non-linear stress wave interactions with the free surface. This source emits Rayleigh waves with polarity opposite to waves emitted by the explosion. The Shoal results were extended to analyse surface waves from the 1962 February 15 Hardhat nuclear test, the 1988 September 14 Soviet Joint Verification Experiment, and the anomalous 1979 August 18 northeast Balapan explosion which exhibits opposite polarity, azimuth-independent source component U1 compared to an explosion. Modelling these tests shows that Rayleigh wave amplitudes generated by the damage source are nearly as large as or larger than amplitudes from the explosion. As such, destructive interference can be drastic, introducing metastable conditions due to the sensitivity of reduced amplitudes to Rayleigh wave initial phase angles of the explosion and damage sources. This meta-stability is a likely source of scatter in M s-yield scaling observations. The agreement of observed scaling exponent b with the model suggests that the damage source strength does not vary much with yield, in contrast to explosions conducted in weak media where Ms scaling rates are greater than the model predicts, and the yield dependence of the damage source strength is significant. This difference in scaling behaviour is a consequence of source medium material properties.« less

A Physical Basis for M s-Yield Scaling in Hard Rock and Implications for Late-Time Damage of the Source Medium

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

Patton, Howard John

Surface wave magnitude M s for a compilation of 72 nuclear tests detonated in hard rock media for which yields and burial depths have been reported in the literature is shown to scale with yield W as a + b × log[W], where a = 2.50 ± 0.08 and b = 0.80 ± 0.05. While the exponent b is consistent with an M s scaling model for fully coupled, normal containment-depth explosions, the intercept a is offset 0.45 magnitude units lower than the model. The cause of offset is important to understand in terms of the explosion source. Hard rockmore » explosions conducted in extensional and compressional stress regimes show similar offsets, an indication that the tectonic setting in which an explosion occurs plays no role causing the offset. The scaling model accounts for the effects of source medium material properties on the generation of 20-s period Rayleigh wave amplitudes. Aided by thorough characterizations of the explosion and tectonic release sources, an extensive analysis of the 1963 October 26 Shoal nuclear test detonated in granite 27 miles southeast of Fallon NV shows that the offset is consistent with the predictions of a material damage source model related to non-linear stress wave interactions with the free surface. This source emits Rayleigh waves with polarity opposite to waves emitted by the explosion. The Shoal results were extended to analyse surface waves from the 1962 February 15 Hardhat nuclear test, the 1988 September 14 Soviet Joint Verification Experiment, and the anomalous 1979 August 18 northeast Balapan explosion which exhibits opposite polarity, azimuth-independent source component U1 compared to an explosion. Modelling these tests shows that Rayleigh wave amplitudes generated by the damage source are nearly as large as or larger than amplitudes from the explosion. As such, destructive interference can be drastic, introducing metastable conditions due to the sensitivity of reduced amplitudes to Rayleigh wave initial phase angles of the explosion and damage sources. This meta-stability is a likely source of scatter in M s-yield scaling observations. The agreement of observed scaling exponent b with the model suggests that the damage source strength does not vary much with yield, in contrast to explosions conducted in weak media where Ms scaling rates are greater than the model predicts, and the yield dependence of the damage source strength is significant. This difference in scaling behaviour is a consequence of source medium material properties.« less

Nuclear Resonance Fluorescence Measurements of High Explosives

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

Caggiano, Joseph A.; Warren, Glen A.; Korbly, Steve

Pacific Northwest National Laboratory and Passport Systems have collaborated to perform Nuclear Resonance Fluorescence experiments using several high quality high-explosive simulant samples. These measurements were conducted to determine the feasibility of finding and characterizing high explosive material by NRF interrogation. Electron beams of 5.1, 5.3, 8, and 10 MeV were used to produce bremsstrahlung photon beams, which irradiated the samples. The gamma-ray spectra were collected using high-purity germanium detectors. Nitrogen-to-carbon ratios of the high-explosive simulants were extracted from the 5.1 and 5.3 MeV data and compare favorably with accepted values. Analysis of the 8 and 10 MeV data is inmore » progress; preliminary isotopic comparisons within the samples are consistent with the expected results.« less

A New Multiphase Equation of State for Composition B

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

Coe, Joshua Damon; Margevicius, Madeline Alma

2016-07-25

We describe the construction of a complete equation of state for the high explosive Composition B in its unreacted (inert) form, as well as chemical equilibrium calculations of its detonation products. The multiphase reactant EOS is of SESAME type, and was calibrated to ambient thermal and mechanical data, the shock initiation experiments of Dattelbaum, et al., and the melt line of trinitrotoluene (TNT).

Collaborative Point Paper on Active Protection Systems

DTIC Science & Technology

2006-10-01

for the Hunter VHP CIED Program. Also, General Dynamics Armament and Technical Products (GDATP), Burlington, VT is contracted by the Marine Corps...the incoming threat at a relatively long distance. Specific details about the composition and mechanism of this explosive interceptor device are...relatively thin shell of ballistic steel and composite armor, also known as hybrid armor, designed to provide optimal protection from specific threats

A Late Holocene explosive mafic eruption of Villarrica volcano, Southern Andes: The Chaimilla deposit

NASA Astrophysics Data System (ADS)

Costantini, L.; Pioli, L.; Bonadonna, C.; Clavero, J.; Longchamp, C.

2011-03-01

Villarrica (Chile) is one of the most active volcanoes in South America having erupted about 60 times in the last 460 years. Although its historical eruptive activity has been mainly effusive and weakly explosive, it had strong explosive behaviour in postglacial times. Chaimilla (< 3.1 ka) is one of the best exposed and widely dispersed pyroclastic deposits, related to both fall and flow activity. The deposit is dispersed over an area of 250 km 2 and consists of 8 units (A-H) which were grouped into four sequences. Stratigraphic data suggest that the eruption had a relatively short duration and evolved from i) an Opening phase, dispersing ash, lapilli clasts, accretionary lapilli, blocks and bombs, to ii) a Pulsatory phase, originating a series of magmatic explosions, to iii) a Collapsing phase, characterised by unstable plumes which emplaced a series of pyroclastic density currents intercalated with thin fallout layers and finally to iv) a Climactic phase forming a more sustained plume which eventually collapsed generating the final pyroclastic density currents. The deposit (fall and flow) has a minimum cumulative volume of 0.6 km 3, with the main sustained phase being associated with a VEI 4 and the flow units having a minimum estimated total volume of 0.04 km 3. The erupted material has a homogenous chemical composition but displays a remarkable variability in both textural and physical properties. The density distribution of juvenile products shows a clear bimodality characterised by two main populations: P1 and P2. Population P1 consists of highly vesicular clasts (modal density around 1000 kg m - 3 ) with mostly sub-spherical bubbles and moderately crystallised groundmass with large-sized microlites. Clasts from population P2 are poorly vesicular (modal density around 1600 kg m - 3 ) with irregular to collapsed bubbles and numerous smaller microlites. The variability of both vesicularity and microlite characteristics suggests the involvement of two magma batches with distinct pre-eruptive degassing and rising histories. Our eruption conceptual model implies the arrival of new magma (represented in the deposit by P1 clasts) into a small, outgassed magma body which was accumulated at shallow level (mainly represented by P2 clasts). A new Chaimilla-type eruption could significantly affect the communities that have recently developed around Villarrica volcano and subsist mainly on tourism and forestry. As a result, a better understanding of the dynamics and evolution of the Chaimilla eruption is necessary for the identification of potential hazard scenarios at Villarrica volcano and, ultimately, for the risk mitigation of this populated area of Southern Chile.

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

Preparation and characterization of copper-graphite composites by electrical explosion of wire in liquid.

PubMed

Bien, T N; Gul, W H; Bac, L H; Kim, J C

2014-11-01

Copper-graphite nanocomposites containing 5 vol.% graphite were prepared by a powder metallurgy route using an electrical wire explosion (EEW) in liquid method and spark plasma sintering (SPS) process. Graphite rods with a 0.3 mm diameter and copper wire with a 0.2 mm diameter were used as raw materials for EEWin liquid. To compare, a pure copper and copper-graphite mixture was also prepared. The fabricated graphite was in the form of a nanosheet, onto which copper particles were coated. Sintering was performed at 900 degrees C at a heating rate of 30 degrees C/min for 10 min and under a pressure of 70 MPa. The density of the sintered composite samples was measured by the Archimedes method. A wear test was performed by a ball-on-disc tribometer under dry conditions at room temperature in air. The presence of graphite effectively reduced the wear of composites. The copper-graphite nanocomposites prepared by EEW had lower wear rates than pure copper material and simple mixed copper-graphite.

Characterization of Detonation Soot Produced During Steady and Overdriven Conditions for Three High Explosive Formulations

NASA Astrophysics Data System (ADS)

Podlesak, David; Amato, Ronald; Dattelbaum, Dana; Firestone, Millicent; Gustavsen, Richard; Huber, Rachel; Ringstrand, Bryan

2015-06-01

The detonation of high explosives (HE) produces a dense fluid of molecular gases and solid carbon. The solid detonation carbon contains various carbon allotropes such as detonation nanodiamonds, ``onion-like'' carbon, graphite and amorphous carbon, with the formation of the different forms dependent upon pressure, temperature and the environmental conditions of the detonation. We have collected solid carbon residues from controlled detonations of three HE formulations (Composition B-3, PBX 9501, and PBX 9502). Soot was collected from experiments designed to produce both steady and overdriven conditions, and from detonations in both an ambient (air) atmosphere and in an inert Ar atmosphere. Structural studies to glean the features of the solid carbon products have been performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, small-angle X-ray scattering (SAXS), and X-Ray Pair Distribution Function measurements (PDF). Bulk soot was also analyzed for elemental and isotopic compositions. We will discuss differences in the structure and composition of the detonation carbon as a function of formulation, detonation conditions, and the surrounding atmosphere.

Explosion Generated Seismic Waves and P/S Methods of Discrimination from Earthquakes with Insights from the Nevada Source Physics Experiments

NASA Astrophysics Data System (ADS)

Walter, W. R.; Ford, S. R.; Pitarka, A.; Pyle, M. L.; Pasyanos, M.; Mellors, R. J.; Dodge, D. A.

2017-12-01

The relative amplitudes of seismic P-waves to S-waves are effective at identifying underground explosions among a background of natural earthquakes. These P/S methods appear to work best at frequencies above 2 Hz and at regional distances ( >200 km). We illustrate this with a variety of historic nuclear explosion data as well as with the recent DPRK nuclear tests. However, the physical basis for the generation of explosion S-waves, and therefore the predictability of this P/S technique as a function of path, frequency and event properties such as size, depth, and geology, remains incompletely understood. A goal of current research, such as the Source Physics Experiments (SPE), is to improve our physical understanding of the mechanisms of explosion S-wave generation and advance our ability to numerically model and predict them. The SPE conducted six chemical explosions between 2011 and 2016 in the same borehole in granite in southern Nevada. The explosions were at a variety of depths and sizes, ranging from 0.1 to 5 tons TNT equivalent yield. The largest were observed at near regional distances, with P/S ratios comparable to much larger historic nuclear tests. If we control for material property effects, the explosions have very similar P/S ratios independent of yield or magnitude. These results are consistent with explosion S-waves coming mainly from conversion of P- and surface waves, and are inconsistent with source-size based models. A dense sensor deployment for the largest SPE explosion allowed this conversion to be mapped in detail. This is good news for P/S explosion identification, which can work well for very small explosions and may be ultimately limited by S-wave detection thresholds. The SPE also showed explosion P-wave source models need to be updated for small and/or deeply buried cases. We are developing new P- and S-wave explosion models that better match all the empirical data. Historic nuclear explosion seismic data shows that the media in which the explosion takes place is quite important. These material property effects can surprisingly degrade the seismic waveform correlation of even closely spaced explosions in different media. The next phase of the SPE will contrast chemical explosions in dry alluvium with the prior SPE explosions in granite and historic nuclear tests in a variety of media.

Identifying explosives using broadband millimeter-wave imaging

NASA Astrophysics Data System (ADS)

Weatherall, James C.; Yam, Kevin; Barber, Jeffrey; Smith, Barry T.; Smith, Peter R.; Greca, Joseph

2017-05-01

Millimeter wave imaging is employed in Advanced Technology Imaging (AIT) systems to screen personnel for concealed explosives and weapons. AIT systems deployed in airports auto-detect potential threats by highlighting their location on a generic outline of a person using imaging data collected over a range of frequency. We show how the spectral information from the imaging data can be used to identify the composition of an anomalous object, in particular if it is an explosive material. The discriminative value of the technique was illustrated on military sheet explosive using millimeter-wave reflection data at frequencies 18 - 40 GHz, and commercial explosives using 2 - 18 GHz, but the free-space measurement was limited to a single horn with a large-area sample. This work extends the method to imaging data collected at high resolution with a 18 - 40 GHz imaging system. The identification of explosives is accomplished by extracting the dielectric constant from the free-space, multifrequency data. The reflection coefficient is a function of frequency because of propagation effects associated with the material's complex dielectric constant, which include interference from multiple reflections and energy loss in the sample. The dielectric constant is obtained by numerically fitting the reflection coefficient as a function of frequency to an optical model. In principal, the implementation of this technique in standoff imaging systems would allow threat assessment to be accomplished within the scope of millimeter-wave screening.

A Supernova Shockwaves

NASA Image and Video Library

2007-06-13

Supernovae are the explosive deaths of the universe most massive stars. This false-color composite from NASA Spitzer Space Telescope and NASA Chandra X-ray Observatory shows the remnant of N132D, the wispy pink shell of gas at center.

Investigating the fate of nitroaromatic (TNT) and nitramine (RDX and HMX) explosives in fractured and pristine soils.

PubMed

Douglas, Thomas A; Walsh, Marianne E; McGrath, Christian J; Weiss, Charles A

2009-01-01

Explosives compounds, known toxins, are loaded to soils on military training ranges predominantly during explosives detonation events that likely fracture soil particles. This study was conducted to investigate the fate of explosives compounds in aqueous slurries containing fractured and pristine soil particles. Three soils were crushed with a piston to emulate detonation-induced fracturing. X-ray diffraction, energy-dispersive X-ray spectrometry, gas adsorption surface area measurements, and scanning electron microscopy were used to quantify and image pristine and fractured soil particles. Aqueous batches were prepared by spiking soils with solutions containing 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 2,4-dinitrotoluene (2,4-DNT). Samples were collected over 92 d and the concentrations of the spiked explosives compounds and TNT transformation products 2-amino-4,6-dinitrotoluene (2ADNT) and 4-amino-2,6-dinitrotoluene (4ADNT) were measured. Our results suggest soil mineralogical and geochemical compositions were not changed during piston-induced fracturing but morphological differences were evident with fractured soils exhibiting more angular surfaces, more fine grained particles, and some microfracturing that is not visible in the pristine samples. TNT, 2,4-DNT, RDX, and HMX exhibited greater analyte loss over time in batch solutions containing fractured soil particles compared to their pristine counterparts. 2ADNT and 4ADNT exhibited greater concentrations in slurries containing pristine soils than in slurries containing fractured soils. Explosives compound transformation is greater in the presence of fractured soil particles than in the presence of pristine soil particles. Our results imply fractured soil particles promote explosive compound transformation and/or explosives compounds have a greater affinity for adsorption to fractured soil particle surfaces.

Report on Transport and Loading of Explosives in the Femtosecond Tank, Room 1711A HEAF 00-010

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

Hill, D L

2002-04-25

The current OSP associated with Room 1711A located in Building 191 (HEAF) sets a limit of 5 grams Net Explosive Weight (NEW) of explosives for the room. A question was raised as to the capability of that room to withstand the overpressure created by a detonation of 5 grams NEW of explosives. Calculations were inconclusive, but indicated the wallboard would not remain intact if there was a detonation of 5 grams NEW at a distance of eight feet from the wall. These calculations did not seem logical. To verify the hypothesis, a series of experiments were conducted in the 1more » Kilogram tank. The experiments consisted of exposing a pre-built double-sided wall with the same stud spacing and drywall thickness found in the walls of Room 1711A to various amounts of explosives to create expected overpressures. The objective of this test was to prove or disprove that the walls in room 1711A could withstand a detonation of 5 grams of high explosives and to determine if larger quantities of explosives could be worked on in the room while still providing the required level of protection for personnel outside the room. Testing has verified that not only can the walls withstand a 5 gram explosion, but a 10.75 gram explosion as well. A second test was conducted using 20 grams of explosive plus a detonator. Although the inner piece of drywall cracked, the outer piece of drywall maintained its integrity, thereby confining the effects of the anticipated overpressure to the room.« less

Detonation failure characterization of non-ideal explosives

NASA Astrophysics Data System (ADS)

Janesheski, Robert S.; Groven, Lori J.; Son, Steven

2012-03-01

Non-ideal explosives are currently poorly characterized, hence limiting the modeling of them. Current characterization requires large-scale testing to obtain steady detonation wave characterization for analysis due to the relatively thick reaction zones. Use of a microwave interferometer applied to small-scale confined transient experiments is being implemented to allow for time resolved characterization of a failing detonation. The microwave interferometer measures the position of a failing detonation wave in a tube that is initiated with a booster charge. Experiments have been performed with ammonium nitrate and various fuel compositions (diesel fuel and mineral oil). It was observed that the failure dynamics are influenced by factors such as chemical composition and confiner thickness. Future work is planned to calibrate models to these small-scale experiments and eventually validate the models with available large scale experiments. This experiment is shown to be repeatable, shows dependence on reactive properties, and can be performed with little required material.

Probing Dynamic Processes in Explosives and Propellants - Science Issues

NASA Astrophysics Data System (ADS)

Moore, David

2017-06-01

Recent experiments on advanced light sources have started to unravel some of the micromechanical behavior of single crystal energetic materials, including void collapse under shock loading and inter-granular failure. These examples just scratch the surface of many extant explosives science issues, which could be elucidated with advanced XFEL-type resources. These include such diverse questions as: How do powders actually compact and what are the spatially and temporally resolved temperature and flow fields generated (especially two-phase flows)? Are there polymorphic effects (if so, how are they spatially distributed)? What are the strain fields during compaction? What happens near surfaces, especially for composite explosives? How is mechanics coupled to chemistry? What are hot spots really? I will provide some history behind these and other questions and point towards how future experiments might be designed to provide some answers.

Eruptive history of the Dieng Mountains region, central Java, and potential hazards from future eruptions

USGS Publications Warehouse

Miller, C. Dan; Sushyar, R.; ,; Hamidi, S.

1983-01-01

The Dieng Mountains region consists of a complex of late Quaternary to recent volcanic stratocones, parasitic vents, and explosion craters. Six age groups of volcanic centers, eruptive products, and explosion craters are recognized in the region based on their morphology, degree of dissection, stratigraphic relationships, and degree of weathering. These features range in age from tens of thousands of years to events that have occurred this century. No magmatic eruptions have occurred in the Dieng Mountains region for at least several thousand years; volcanic activity during this time interval has consisted of phreatic eruptions and non-explosive hydrothermal activity. If future volcanic events are similar to those of the last few thousand years, they will consist of phreatic eruptions, associated small hot mudflows, emission of suffocating gases, and hydrothermal activity. Future phreatic eruptions may follow, or accompany, periods of increased earthquake activity; the epicenters for the seismicity may suggest where eruptive activity will occur. Under such circumstances, the populace within several kilometers of a potential eruption site should be warned of a possible eruption, given instructions about what to do in the event of an eruption, or temporarily evacuated to a safer location.

Effect of shock pressure on the structure and superconducting properties of Y-Ba-Cu-O in explosively fabricated bulk metal-matrix composites

NASA Technical Reports Server (NTRS)

Murr, L. E.; Niou, C. S.; Pradhan-Advani, M.

1991-01-01

While it is now well established that copper-oxide-based power, or virtually any other ceramic superconductor powder, can be consolidated and encapsulated within a metal matrix by explosive consolidation, the erratic superconductivity following fabrication has posed a major problem for bulk applications. The nature of this behavior was found to arise from microstructural damage created in the shock wave front, and the residual degradation in superconductivity was demonstrated to be directly related to the peak shock pressure. The explosively fabricated or shock loaded YBa2Cu3Ox examples exhibit drastically altered rho (or R) - T curves. The deterioration in superconductivity is even more noticeable in the measurement of ac magnetic susceptibility and flux exclusion or shielding fraction which is also reduced in proportion to increasing peak shock pressure. The high frequency surface resistance (in the GHz range) is also correspondingly compromised in explosively fabricated, bulk metal-matrix composites based on YBa2Cu3O7. Transmission electron microscopy (including lattice imaging techniques) is being applied in an effort to elucidate the fundamental (microstructural) nature of the shock-induced degradation of superconductivity and normal state conductivity. One focus of TEM observations has assumed that oxygen displaced from b-chains rather than oxygen-vacancy disorder in the basal plane of oxygen deficient YBa2Cu3Ox may be a prime mechanism. Shock-wave displaced oxygen may also be locked into new positions or interstitial clusters or chemically bound to displaced metal (possibly copper) atoms to form precipitates, or such displacements may cause the equivalent of local lattice cell changes as a result of stoichiometric changes. While the shock-induced suppression of T(sub c) is not desirable in the explosive fabrication of bulk metal-matrix superconductors, it may be turned into an advantage if the atomic-scale distortion can be understood and controlled as local flux pinning sites.

Effect of shock pressure on the structure and superconducting properties of Y-Ba-Cu-O in explosively fabricated bulk metal-matrix composites

NASA Technical Reports Server (NTRS)

Murr, L. E.; Niou, C. S.; Pradhan, M.; Schoenlein, L. H.

1990-01-01

While it is now well established that copper-oxide-based powder, or virtually any other ceramic superconductor powder, can be consolidated and encapsulated within a metal matrix by explosive consolidation, the erratic superconductivity following fabrication has posed a major problem for bulk applications. The nature of this behavior was found to arise from microstructural damage created in the shock wave front, and the residual degradation in superconductivity was demonstrated to be directly related to the peak shock pressure. The explosively fabricated or shock loaded YBa2Cu3Ox examples exhibit drastically altered rho (or R) - T curves. The deterioration in superconductivity is even more noticeable in the measurement of ac magnetic susceptibility and flux exclusion or shielding fraction which is also reduced in proportion to increasing peak shock pressure. The high-frequency surface resistance (in the GHz range) is also correspondingly compromised in explosively fabricated, bulk metal-matrix composites based on YBa2Cu3O7. Transmission electron microscopy (including lattice imaging techniques) is being applied in an effort to elucidate the fundamental (microstructural) nature of the shock-induced degradation of superconductivity and normal state conductivity. One focus of TEM observations has assumed that oxygen displaced from b-chains rather than oxygen-vacancy disorder in the basal plane of oxygen deficient YBa2Cu3Ox may be a prime mechanism. Shock-wave displaced oxygen may also be locked into new positions or interstitial clusters or chemically bound to displaced metal (possibly copper) atoms to form precipitates, or such displacements may cause the equivalent of local lattice cell changes as a result of stoichiometric changes. While the shock-induced suppression of T(sub c) is not desirable in the explosive fabrication of bulk metal-matrix superconductors, it may be turned into an advantage if the atomic-scale distortion can be understood and controlled as local flux pinning sites.

Modeling normal shock velocity curvature relations for heterogeneous explosives

NASA Astrophysics Data System (ADS)

Yoo, Sunhee; Crochet, Michael; Pemberton, Steven

2017-01-01

The theory of Detonation Shock Dynamics (DSD) is, in part, an asymptotic method to model a functional form of the relation between the shock normal, its time rate and shock curvature κ. In addition, the shock polar analysis provides a relation between shock angle θ and the detonation velocity Dn that is dependent on the equations of state (EOS) of two adjacent materials. For the axial detonation of an explosive material confined by a cylinder, the shock angle is defined as the angle between the shock normal and the normal to the cylinder liner, located at the intersection of the shock front and cylinder inner wall. Therefore, given an ideal explosive such as PBX-9501 with two functional models determined, a unique, smooth detonation front shape ψ can be determined that approximates the steady state detonation shock front of the explosive. However, experimental measurements of the Dn(κ) relation for heterogeneous explosives such as PBXN-111 [D. K. Kennedy, 2000] are challenging due to the non-smoothness and asymmetry usually observed in the experimental streak records of explosion fronts. Out of many possibilities the asymmetric character may be attributed to the heterogeneity of the explosives; here, material heterogeneity refers to compositions with multiple components and having a grain morphology that can be modeled statistically. Therefore in extending the formulation of DSD to modern novel explosives, we pose two questions: (1) is there any simple hydrodynamic model that can simulate such an asymmetric shock evolution, and (2) what statistics can be derived for the asymmetry using simulations with defined structural heterogeneity in the unreacted explosive? Saenz, Taylor and Stewart [1] studied constitutive models for derivation of the Dn(κ) relation for porous homogeneous explosives and carried out simulations in a spherical coordinate frame. In this paper we extend their model to account for heterogeneity and present shock evolutions in heterogeneous explosives using 2-D hydrodynamic simulations with some statistical examination. As an initial work, we assume that the heterogeneity comes from the local density variation or porosity only.

Effect of acid, steam explosion, and size reduction pretreatments on bio-oil production from sweetgum, switchgrass, and corn stover.

PubMed

Wang, Hui; Srinivasan, Radhakrishnan; Yu, Fei; Steele, Philip; Li, Qi; Mitchell, Brian; Samala, Aditya

2012-05-01

Bio-oil produced from biomass by fast pyrolysis has the potential to be a valuable substitute for fossil fuels. In a recent work on pinewood, we found that pretreatment alters the structure and chemical composition of biomass, which influence fast pyrolysis. In this study, we evaluated dilute acid, steam explosion, and size reduction pretreatments on sweetgum, switchgrass, and corn stover feedstocks. Bio-oils were produced from untreated and pretreated feedstocks in an auger reactor at 450 °C. The bio-oil's physical properties of pH, water content, acid value, density, and viscosity were measured. The chemical characteristics of the bio-oils were determined by gas chromatography-mass spectrometry. The results showed that bio-oil yield and composition were influenced by the pretreatment method and feedstock type. Bio-oil yields of 52, 33, and 35 wt% were obtained from medium-sized (0.68-1.532 mm) untreated sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from other sizes. Bio-oil yields of 56, 46, and 51 wt% were obtained from 1% H(2)SO(4)-treated medium-sized sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from untreated and steam explosion treatments.

Pleistocene volcaniclastic units from North-Eastern Sicily (Italy): new evidence for calc-alkaline explosive volcanism in the Southern Tyrrhenian Sea

NASA Astrophysics Data System (ADS)

Di Bella, Marcella; Italiano, Francesco; Sabatino, Giuseppe; Tripodo, Alessandro; Baldanza, Angela; Casella, Sergio; Pino, Paolo; Rasa', Riccardo; Russo, Selma

2016-08-01

A well-preserved volcaniclastic sequence crops out in Pleistocene marine sediments along the Tyrrhenian coastline of the Calabrian-Peloritani arc (Sicily, Italy), testifying the occurrence of Lower-Middle Pleistocene volcanic activity in Southern Tyrrhenian Sea. The presence of dominant highly vesicular and minor blocky glassy particles indicates that the volcanic clasts were originated by explosive events related to the ascent and violent emission of volatile-rich magmas accompanied by and/or alternated with hydromagmatic fragmentation due to magma-sea water interaction. Field investigations and sedimentological features of the studied volcaniclastic units suggest a deposition from sediment-water density flows. The chemical classification of the pumice clasts indicates prevalent rhyolitic and dacitic compositions with calc-alkaline to high-K calc-alkaline affinity. The geochemical features of immobile trace elements together with the presence of orthopyroxene are indicative of a provenance from an arc-type environment. The age (from 980-910 to 589 ka), the chemical composition and the evidence of subaerial explosive volcanic activity constrain the origin nature and temporal evolution of the arc-type volcanism in the Southern Tyrrhenian domain. Finally, the new information here provided contribute to a better understanding of the temporal geodynamic evolution of this sector of the Mediterranean domain.

Shock-to-detonation transition of RDX and NTO based composite high explosives: experiments and modeling

NASA Astrophysics Data System (ADS)

Baudin, Gerard; Roudot, Marie; Genetier, Marc

2013-06-01

Composite HMX and NTO based high explosives (HE) are widely used in ammunitions. Designing modern warheads needs robust and reliable models to compute shock ignition and detonation propagation inside HE. Comparing to a pressed HE, a composite HE is not porous and the hot-spots are mainly located at the grain - binder interface leading to a different behavior during shock-to-detonation transition. An investigation of how shock-to-detonation transition occurs inside composite HE containing RDX and NTO is proposed in this lecture. Two composite HE have been studied. The first one is HMX - HTPB 82:18. The second one is HMX - NTO - HTPB 12:72:16. These HE have been submitted to plane sustained shock waves at different pressure levels using a laboratory powder gun. Pressure signals are measured using manganin gauges inserted at several distances inside HE. The corresponding run-distances to detonation are determined using wedge test experiments where the plate impact is performed using a powder gun. Both HE exhibit a single detonation buildup curve in the distance - time diagram of shock-to-detonation transition. This feature seems a common shock-to-detonation behavior for composite HE without porosity. This behavior is also confirmed for a RDX - HTPB 85:15 based composite HE. Such a behavior is exploited to determine the heterogeneous reaction rate versus the shock pressure using a method based on the Cauchy-Riemann problem inversion. The reaction rate laws obtained allow to compute both run-distance to detonation and pressure signals.

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.

The latest explosive eruptions of Ciomadul (Csomád) volcano, East Carpathians - A tephrostratigraphic approach for the 51-29 ka BP time interval

NASA Astrophysics Data System (ADS)

Karátson, D.; Wulf, S.; Veres, D.; Magyari, E. K.; Gertisser, R.; Timar-Gabor, A.; Novothny, Á.; Telbisz, T.; Szalai, Z.; Anechitei-Deacu, V.; Appelt, O.; Bormann, M.; Jánosi, Cs.; Hubay, K.; Schäbitz, F.

2016-06-01

The most recent, mainly explosive eruptions of Ciomadul, the youngest volcano in the Carpatho-Pannonian Region, have been constrained by detailed field volcanological studies, major element pumice glass geochemistry, luminescence and radiocarbon dating, and a critical evaluation of available geochronological data. These investigations were complemented by the first tephrostratigraphic studies of the lacustrine infill of Ciomadul's twin craters (St. Ana and Mohoş) that received tephra deposition during the last eruptions of the volcano. Our analysis shows that significant explosive activity, collectively called EPPA (Early Phreatomagmatic and Plinian Activity), started at Ciomadul in or around the present-day Mohoş, the older crater, at ≥ 51 ka BP. These eruptions resulted in a thick succession of pyroclastic-fall deposits found in both proximal and medial/distal localities around the volcano, characterized by highly silicic (rhyolitic) glass chemical compositions (ca. 75.2-79.8 wt.% SiO2). The EPPA stage was terminated by a subplinian/plinian eruption at ≥ 43 ka BP, producing pumiceous pyroclastic-fall and -flow deposits of similar glass composition, probably from a "Proto-St. Ana" vent located at or around the younger crater hosting the present-day Lake St. Ana. After a quiescent period with a proposed lava dome growth in the St. Ana crater, a new explosive stage began, defined as MPA (Middle Plinian Activity). In particular, a significant two-phase eruption occurred at 31.5 ka BP, producing pyroclastic flows from vulcanian explosions disrupting the preexisting lava dome of Sf. Ana, and followed by pumiceous fallout from a plinian eruption column. Related pyroclastic deposits show a characteristic, less evolved rhyolitic glass composition (ca. 70.2-74.5 wt.% SiO2) and occur both in proximal and medial/distal localities up to 21 km from source. The MPA eruptions, that may have pre-shaped a crater similar to, but possibly smaller than, the present-day St. Ana crater, was followed by a so far unknown, but likewise violent last eruptive stage from the same vent, creating the final morphology of the crater. This stage, referred to as LSPA (Latest St. Ana Phreatomagmatic Activity), produced pyroclastic-fall deposits of more evolved rhyolitic glass composition (ca. 72.8-78.8 wt.% SiO2) compared to that of the previous MPA stage. According to radiocarbon age constraints on bulk sediment, charcoal and organic matter from lacustrine sediments recovered from both craters, the last of these phreatomagmatic eruptions - that draped the landscape toward the east and southeast of the volcano - occurred at 29.6 ka BP, some 2000 years later than the previously suggested last eruption of Ciomadul.

A simplified method for determining reactive rate parameters for reaction ignition and growth in explosives

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

Miller, P.J.

1996-07-01

A simplified method for determining the reactive rate parameters for the ignition and growth model is presented. This simplified ignition and growth (SIG) method consists of only two adjustable parameters, the ignition (I) and growth (G) rate constants. The parameters are determined by iterating these variables in DYNA2D hydrocode simulations of the failure diameter and the gap test sensitivity until the experimental values are reproduced. Examples of four widely different explosives were evaluated using the SIG model. The observed embedded gauge stress-time profiles for these explosives are compared to those calculated by the SIG equation and the results are described.

MODELING SNR CASSIOPEIA A FROM THE SUPERNOVA EXPLOSION TO ITS CURRENT AGE: THE ROLE OF POST-EXPLOSION ANISOTROPIES OF EJECTA

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

Orlando, S.; Miceli, M.; Pumo, M. L.

The remnants of core-collapse supernovae (SNe) have complex morphologies that may reflect asymmetries and structures developed during the progenitor SN explosion. Here we investigate how the morphology of the supernova remnant Cassiopeia A (Cas A) reflects the characteristics of the progenitor SN with the aim of deriving the energies and masses of the post-explosion anisotropies responsible for the observed spatial distribution of Fe and Si/S. We model the evolution of Cas A from the immediate aftermath of the progenitor SN to the three-dimensional interaction of the remnant with the surrounding medium. The post-explosion structure of the ejecta is described bymore » small-scale clumping of material and larger-scale anisotropies. The hydrodynamic multi-species simulations consider an appropriate post-explosion isotopic composition of the ejecta. The observed average expansion rate and shock velocities can be well reproduced by models with ejecta mass M {sub ej} ≈ 4 M {sub ⊙} and explosion energy E {sub SN} ≈ 2.3 × 10{sup 51} erg. The post-explosion anisotropies (pistons) reproduce the observed distributions of Fe and Si/S if they had a total mass of ≈0.25 M {sub ⊙} and a total kinetic energy of ≈1.5 × 10{sup 50} erg. The pistons produce a spatial inversion of ejecta layers at the epoch of Cas A, leading to the Si/S-rich ejecta physically interior to the Fe-rich ejecta. The pistons are also responsible for the development of the bright rings of Si/S-rich material which form at the intersection between the reverse shock and the material accumulated around the pistons during their propagation. Our result supports the idea that the bulk of asymmetries observed in Cas A are intrinsic to the explosion.« less

Identifying explosives by dielectric properties obtained through wide-band millimeter-wave illumination

NASA Astrophysics Data System (ADS)

Weatherall, James C.; Barber, Jeffrey; Smith, Barry T.

2015-05-01

A method for extracting dielectric constant from free-space 18 - 40 GHz millimeter-wave reflection data is demonstrated. The reflection coefficient is a function of frequency because of propagation effects, and numerically fitting data to a theoretical model based on geometric optics gives a solution for the complex dielectric constant and target thickness. The discriminative value is illustrated with inert substances and military sheet explosive. In principle, the measurement of reflectivity across multiple frequencies can be incorporated into Advanced Imaging Technology (AIT) systems to automatically identify the composition of anomalies detected on persons at screening checkpoints.

F region above Kauai - Measurement, model, modification

NASA Technical Reports Server (NTRS)

Johnson, C. Y.; Sjolander, G. W.; Oran, E. S.; Young, T. R.; Bernhardt, P. A.; Da Rosa, A. V.

1980-01-01

Results of the Lagopedo II experiment conducted from Kauai, Hawaii to investigate the ionospheric modification that occurs when rocket combustion products are introduced into the O(+)-rich F region are presented. The experiment involved the detonation of a chemical explosion in the F2 peak accompanied by rocket-borne measurements of ion composition and electron content in the vicinity of the explosion. The experimental data is found to be in good agreement with the predictions of a model of the nighttime ion densities in the midlatitude laminar ionosphere, with the exception of N2(+) densities before the explosion. H2O(+) and H3O(+) currents produced by considerable H2O outgassing from the rocket are used to determine a H3O(+)/H2O(+) dissociative recombination rate averaging 1.6 to 1.08, depending on model assumptions. At the time of the explosion, an ionic void 1 km in radius is observed, the boundary of which is characterized by a steep gradient in ionic densities. Evidence of variations in the concentrations of ambient ion species, new reactant species and ionic depletion by sweeping is also obtained.

Explosion characteristics of synthesised biogas at various temperatures.

PubMed

Dupont, L; Accorsi, A

2006-08-25

Biogas is considered as a valuable source of renewable energy. Indeed, it can be turned into useful energy (heat, electricity, fuel) and can contribute to reduce greenhouse gas emissions. Knowledge of its safety characteristics is a very important practical issue. Experimental investigation of synthesised biogas explosion characteristics was conducted in a 20-L sphere at various temperatures (30-70 degrees C) and at atmospheric pressure. The studied biogas was made of 50% methane (CH(4)) and 50% carbon dioxide (CO(2)). It was also saturated with humidity: this composition is frequently met in digesters during waste methanisation. There are two inert gases in biogas: water vapour and carbon dioxide. Its vapour water content rises along with temperature. The presence of these inert gases modifies considerably biogas characteristics compared to the ones of pure methane: explosion limits are lowered and beyond 70 degrees C, water vapour content is sufficient to inert the mixture. Furthermore, explosion violence (estimated with the maximum rate of pressure rise values, (dp/dt)(max)) is three times lower for biogas than for pure methane at ambient temperature.

Controlling state explosion during automatic verification of delay-insensitive and delay-constrained VLSI systems using the POM verifier

NASA Technical Reports Server (NTRS)

Probst, D.; Jensen, L.

1991-01-01

Delay-insensitive VLSI systems have a certain appeal on the ground due to difficulties with clocks; they are even more attractive in space. We answer the question, is it possible to control state explosion arising from various sources during automatic verification (model checking) of delay-insensitive systems? State explosion due to concurrency is handled by introducing a partial-order representation for systems, and defining system correctness as a simple relation between two partial orders on the same set of system events (a graph problem). State explosion due to nondeterminism (chiefly arbitration) is handled when the system to be verified has a clean, finite recurrence structure. Backwards branching is a further optimization. The heart of this approach is the ability, during model checking, to discover a compact finite presentation of the verified system without prior composition of system components. The fully-implemented POM verification system has polynomial space and time performance on traditional asynchronous-circuit benchmarks that are exponential in space and time for other verification systems. We also sketch the generalization of this approach to handle delay-constrained VLSI systems.

Explosives signatures and analysis

NASA Astrophysics Data System (ADS)

Fountain, Augustus Way, III; Oyler, Jonathan M.; Ostazeski, Stanley A.

2008-04-01

The challenge of sampling explosive materials for various high threat military and civilian operational scenarios requires the community to identify and exploit other chemical compounds within the mixtures that may be available to support stand-off detection techniques. While limited surface and vapor phase characterization of IEDs exist, they are insufficient to guide the future development and evaluation of field deployable explosives detection (proximity and standoff) capabilities. ECBC has conducted a limited investigation of three artillery ammunition types to determine what chemical vapors, if any, are available for sensing; the relative composition of the vapors which includes the more volatile compounds in munitions, i.e., plastersizers and binders; and the sensitivity needed detect these vapors at stand-off. Also in partnership with MIT-Lincoln Laboratory, we performed a background measurement campaign at the National Training Center to determine the baseline ambient amounts and variability of nitrates and nitro-ester compounds as vapors, particulates, and on surfaces; as well as other chemical compounds related to non-energetic explosive additives. Environmental persistence studies in contexts relevant to counter-IED sensing operations, such as surface residues, are still necessary.

Estimation of the Reactive Flow Model Parameters for an Ammonium Nitrate-Based Emulsion Explosive Using Genetic Algorithms

NASA Astrophysics Data System (ADS)

Ribeiro, J. B.; Silva, C.; Mendes, R.

2010-10-01

A real coded genetic algorithm methodology that has been developed for the estimation of the parameters of the reaction rate equation of the Lee-Tarver reactive flow model is described in detail. This methodology allows, in a single optimization procedure, using only one experimental result and, without the need of any starting solution, to seek the 15 parameters of the reaction rate equation that fit the numerical to the experimental results. Mass averaging and the plate-gap model have been used for the determination of the shock data used in the unreacted explosive JWL equation of state (EOS) assessment and the thermochemical code THOR retrieved the data used in the detonation products' JWL EOS assessments. The developed methodology was applied for the estimation of the referred parameters for an ammonium nitrate-based emulsion explosive using poly(methyl methacrylate) (PMMA)-embedded manganin gauge pressure-time data. The obtained parameters allow a reasonably good description of the experimental data and show some peculiarities arising from the intrinsic nature of this kind of composite explosive.

Self-consistent calculation of the nuclear composition in hot and dense stellar matter

NASA Astrophysics Data System (ADS)

Furusawa, Shun; Mishustin, Igor

2017-03-01

We investigate the mass fractions and in-medium properties of heavy nuclei in stellar matter at characteristic densities and temperatures for supernova (SN) explosions. The individual nuclei are described within the compressible liquid-drop model taking into account modifications of bulk, surface, and Coulomb energies. The equilibrium properties of nuclei and the full ensemble of heavy nuclei are calculated self-consistently. It is found that heavy nuclei in the ensemble are either compressed or decompressed depending on the isospin asymmetry of the system. The compression or decompression has a little influence on the binding energies, total mass fractions, and average mass numbers of heavy nuclei, although the equilibrium densities of individual nuclei themselves are changed appreciably above one-hundredth of normal nuclear density. We find that nuclear structure in the single-nucleus approximation deviates from the actual one obtained in the multinucleus description, since the density of free nucleons is different between these two descriptions. This study indicates that a multinucleus description is required to realistically account for in-medium effects on the nuclear structure in supernova matter.

Improved Event Location Uncertainty Estimates

DTIC Science & Technology

2008-06-30

throughout this study . The data set consists of GT0-2 nuclear explosions from the SAIC Nuclear Explosion Database (www.rdss.info, Bahavar et al...errors: Bias and variance In this study SNR dependence of both delay and variance of reading errors of first arriving P waves are analyzed and...ground truth and range of event size. For other datasets we turn to estimates based on double- differences between arrival times of station pairs

Investigation of the Explosive Potential of the Hybrid Propellant Combinations N2O4/PBAN and CTF/PBAN

DTIC Science & Technology

1967-03-01

nitrogen tetroxide (N„0 ) and polybutadyne-aluminum (PBAN), and chlorine trifluoride (CTF) and PBAN. This program consisted of a series of eight...explosive potential of two hybrid propellant combinations; nitrogen tetroxide QLOL) and polybutadyne - aluminum (PBAN) and chlorine triflouride (CTF...or positive-phase impulse yield. FREE AIR OVERPRESSURE: (OR FREE FIELD OVERPRESSURE): The unreflected pressure, in excess of the ambient atmospheric

Warhead Performance Calculations for Threat Hazard Assessment

DTIC Science & Technology

1996-08-01

0.59 PBXN -107 1.41 1.45 0.925 0.924 PBXN -109 1.34 1.44 1.19 0.6 AFX-931 1.16 1.43 1.08 0.23 data AH comb,x mdet,x) mcomb,TNT* &omb,TNT a *AHmmb,m...k] (45) EW = E/(4.610 x 106 ) , explosive yield in TNT equivalents, kg; with E in joules. where E = energy of explosion in consistent units V

Explosive Cyclogenesis Over the Eastern United States.

NASA Astrophysics Data System (ADS)

MacDonald, Bruce Calvin

Cases of explosive cyclogenesis occurring over the east central United States are identified and analyzed. Other selected cases of weak or nonintensifying cyclones over the same area are identified and studied for comparative purposes. Signatures of explosively deepening cyclones (bombs) are derived from the analyses, including vertical profiles of vorticity, divergence, and latent heating, and also the relative importance of terms in the vorticity tendency equation and the relative importance of convective and stable latent heating. Composite analyses for the differing phases of bomb development and for regular cyclones are presented. Analyses of individual cases reveal the importance of a low-level jet streak, low-level moisture content, and moisture gradients in the lower troposphere. A numerical model is used to further examine the important processes in explosive cyclogenesis. A mesoscale feature is introduced to improve the prediction of sea -level pressure. This feature is based on the tendency of the large scale height field and vorticity field to adjust concurrently at each time step. The model is also used to provide air parcel trajectories to indicate the importance of parcels with high vorticity and moisture content as an ingredient in explosive cyclogenesis. Sensitivity studies are carried out with the model in order to determine the effect of changes in the initial vorticity and moisture field on cyclogenesis.

Evaluation of sulfur dioxide emissions from explosive volcanism: the 1982-1983 eruptions of Galunggung, Java, Indonesia

USGS Publications Warehouse

Bluth, G.J.S.; Casadevall, T.J.; Schnetzler, C.C.; Doiron, S.D.; Walter, Louis S.; Krueger, A.J.; Badruddin, M.

1994-01-01

Galunggung volcano, Java, awoke from a 63-year quiescence in April 1982, and erupted sporadically through January 1983. During its most violent period from April to October, the Cikasasah Volcano Observatory reported 32 large and 56 moderate to small eruptions. From April 5 through September 19 the Total Ozone Mapping Spectrometer (TOMS), carried on NASA's Nimbus-7 satellite, detected and measured 24 different sulfur dioxide clouds; an estimated 1730 kilotons (kt) of SO2 were outgassed by these explosive eruptions. The trajectories, and rapid dispersion rates, of the SO2 clouds were consistent with injection altitudes below the tropopause. An additional 300 kt of SO2 were estimated to have come from 64 smaller explosive eruptions, based on the detection limit of the TOMS instrument. For the first time, an extended period of volcanic activity was monitored by remote sensing techniques which enabled observations of both the entire SO2 clouds produced by large explosive eruptions (using TOMS), and the relatively lower levels of SO2 emissions during non-explosive outgassing (using the Correlation Spectrometer, or COSPEC). Based on COSPEC measurements from August 1982 to January 1983, and on the relationship between explosive and non-explosive degassing, approximately 400 kt of SO2 were emitted during non-explosive activity. The total sulfur dioxide outgassed from Galunggung volcano from April 1982 to January 1983 is calculated to be 2500 kt (?? 30%) from both explosive and non-explosive activity. While Galunggung added large quantities of sulfur dioxide to the atmosphere, its sporadic emissions occurred in relatively small events distributed over several months, and reached relatively low altitudes, and are unlikely to have significantly affected aerosol loading of the stratosphere in 1982 by volcanic activity. ?? 1994.

Frictional properties of single crystals HMX, RDX and PETN explosives.

PubMed

Wu, Y Q; Huang, F L

2010-11-15

The frictional properties of single crystals of cyclotetramethylene tetranitramine (HMX), cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN) secondary explosives are examined using a sensitive friction machine. The explosive crystals used for the measurements are at least 3.5 mm wide. The friction coefficients between crystals of the same explosive (i.e., HMX on HMX, etc.), crystals of different explosives (i.e., HMX on RDX, etc.), and each explosive and a well-polished gauge steel surface are determined. The frictional surfaces are also studied under an environmental scanning electron microscope (ESEM) to analyze surface microstructural changes under increasing loading forces. The friction coefficients vary considerably with increasing normal loading forces and are particularly sensitive to slider shapes, crystal roughness and the mechanical properties of both the slider and the sample. With increasing loading forces, most friction experiments show surface damage, consisting of grooves, debris, and nano-particles, on both the slider and sample. In some cases, a strong evidence of a localized molten state is found in the central region of the friction track. Possible mechanisms that affect the friction coefficient are discussed based on microscopic observations. Copyright © 2010 Elsevier B.V. All rights reserved.

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.

A service-based framework for pharmacogenomics data integration

NASA Astrophysics Data System (ADS)

Wang, Kun; Bai, Xiaoying; Li, Jing; Ding, Cong

2010-08-01

Data are central to scientific research and practices. The advance of experiment methods and information retrieval technologies leads to explosive growth of scientific data and databases. However, due to the heterogeneous problems in data formats, structures and semantics, it is hard to integrate the diversified data that grow explosively and analyse them comprehensively. As more and more public databases are accessible through standard protocols like programmable interfaces and Web portals, Web-based data integration becomes a major trend to manage and synthesise data that are stored in distributed locations. Mashup, a Web 2.0 technique, presents a new way to compose content and software from multiple resources. The paper proposes a layered framework for integrating pharmacogenomics data in a service-oriented approach using the mashup technology. The framework separates the integration concerns from three perspectives including data, process and Web-based user interface. Each layer encapsulates the heterogeneous issues of one aspect. To facilitate the mapping and convergence of data, the ontology mechanism is introduced to provide consistent conceptual models across different databases and experiment platforms. To support user-interactive and iterative service orchestration, a context model is defined to capture information of users, tasks and services, which can be used for service selection and recommendation during a dynamic service composition process. A prototype system is implemented and cases studies are presented to illustrate the promising capabilities of the proposed approach.

Simulation of Impact Phenomena on the Composite Structures Containing Ceramic Plates and High Entropy Alloys

NASA Astrophysics Data System (ADS)

Geantă, V.; Cherecheș, T.; Lixandru, P.; Voiculescu, I.; Ștefănoiu, R.; Dragnea, D.; Zecheru, T.; Matache, L.

2017-06-01

Due to excellent mechanical properties, high entropy alloys from the system AlxCrFeCoNi can be used successfully to create composite structures containing both metallic and ceramic plates, which resists at dynamic load during high speeds impact (like projectiles, explosion). The paper presents four different composite structures made from a combination of metallic materials and ceramics plates: duralumin-ceramics, duralumin-ceramics-HEA, HEA-ceramics-HEA, HEA-ceramics-duralumin. Numerical simulation of impact behavior of the composite structures was performed by virtual methods, taking into account the mechanical properties of both materials. The best results were obtained using composite structures HEA-ceramics-HEA, HEA-ceramics-duralumin.

Explosive detection technology

NASA Astrophysics Data System (ADS)

Doremus, Steven; Crownover, Robin

2017-05-01

The continuing proliferation of improvised explosive devices is an omnipresent threat to civilians and members of military and law enforcement around the world. The ability to accurately and quickly detect explosive materials from a distance would be an extremely valuable tool for mitigating the risk posed by these devices. A variety of techniques exist that are capable of accurately identifying explosive compounds, but an effective standoff technique is still yet to be realized. Most of the methods being investigated to fill this gap in capabilities are laser based. Raman spectroscopy is one such technique that has been demonstrated to be effective at a distance. Spatially Offset Raman Spectroscopy (SORS) is a technique capable of identifying chemical compounds inside of containers, which could be used to detect hidden explosive devices. Coherent Anti-Stokes Raman Spectroscopy (CARS) utilized a coherent pair of lasers to excite a sample, greatly increasing the response of sample while decreasing the strength of the lasers being used, which significantly improves the eye safety issue that typically hinders laser-based detection methods. Time-gating techniques are also being developed to improve the data collection from Raman techniques, which are often hindered fluorescence of the test sample in addition to atmospheric, substrate, and contaminant responses. Ultraviolet based techniques have also shown significant promise by greatly improved signal strength from excitation of resonance in many explosive compounds. Raman spectroscopy, which identifies compounds based on their molecular response, can be coupled with Laser Induced Breakdown Spectroscopy (LIBS) capable of characterizing the sample's atomic composition using a single laser.

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.

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.

Ultrasonic approach to the synthesis of HMX@TATB core-shell microparticles with improved mechanical sensitivity.

PubMed

Huang, Bing; Hao, Xiaofei; Zhang, Haobin; Yang, Zhijian; Ma, Zhigang; Li, Hongzhen; Nie, Fude; Huang, Hui

2014-07-01

To improve the safety of sensitive explosive HMX while maintaining explosion performance, a moderately powerful but insensitive explosive TATB was used to coat HMX microparticles via a facile ultrasonic method. By using Estane as surface modifier and nano-sized TATB as the shell layer, the HMX@TATB core-shell microparticles with a monodisperse size and compact shell structure were successfully constructed. Both scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of perfect core-shell structured composites. Based on a systematic and comparative study of the effect of experimental conditions, a possible formation mechanism of core-shell structure was proposed in detail. Moreover, the perfect core-shell HMX@TATB microparticles exhibited a unique thermal behavior and significantly improved mechanical sensitivity compared with that of the physical mixture. Copyright © 2014 Elsevier B.V. All rights reserved.

Corn stover for biogas production: Effect of steam explosion pretreatment on the gas yields and on the biodegradation kinetics of the primary structural compounds.

PubMed

Lizasoain, Javier; Trulea, Adrian; Gittinger, Johannes; Kral, Iris; Piringer, Gerhard; Schedl, Andreas; Nilsen, Paal J; Potthast, Antje; Gronauer, Andreas; Bauer, Alexander

2017-11-01

This study evaluated the effect of steam explosion on the chemical composition and biomethane potential of corn stover using temperatures ranging between 140 and 220°C and pretreatment times ranging between 2 and 15min. Biodegradation kinetics during the anaerobic digestion of untreated and corn stover, pretreated at two different intensities, 140°C for 5min and 180°C for 5min, were studied in tandem. Results showed that pretreatment at 160°C for 2min improved the methane yield by 22%. Harsher pretreatment conditions led to lower hemicellulose contents and methane yields, as well as higher lignin contents, which may be due to the formation of pseudo-lignin. The biodegradation kinetics trial demonstrated that steam explosion enhances the degradation of structural carbohydrates and acid insoluble lignin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polymer system for gettering hydrogen

DOEpatents

Shepodd, Timothy Jon; Whinnery, LeRoy L.

2000-01-01

A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

Polymer formulations for gettering hydrogen

DOEpatents

Shepodd, Timothy Jon; Whinnery, LeRoy L.

1998-11-17

A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

Fiber release from impacted graphite reinforced epoxy composites

NASA Technical Reports Server (NTRS)

Babinsky, T. C.

1980-01-01

Carbon fibers released from composites by aircraft fires and crashes can cause electrical shorts and consequent equipment damage. This report investigates less vigorous release mechanisms than that previously simulated by explosive burn/blast tests. When AS/3501-6 composites are impacted by various head and weight configurations of a pendulum impactor, less than 0.2 percent by weight of the original sample is released as single fibers. Other fiber release mechanisms studied were air blasts, constant airflow, torsion, flexural, and vibration of composite samples. The full significance of the low single fiber release rates found here is to be evaluated by NASA in their aircraft vulnerability studies.

The Detection Rate of Early UV Emission from Supernovae: A Dedicated Galex/PTF Survey and Calibrated Theoretical Estimates

NASA Astrophysics Data System (ADS)

Ganot, Noam; Gal-Yam, Avishay; Ofek, Eran. O.; Sagiv, Ilan; Waxman, Eli; Lapid, Ofer; Kulkarni, Shrinivas R.; Ben-Ami, Sagi; Kasliwal, Mansi M.; The ULTRASAT Science Team; Chelouche, Doron; Rafter, Stephen; Behar, Ehud; Laor, Ari; Poznanski, Dovi; Nakar, Ehud; Maoz, Dan; Trakhtenbrot, Benny; WTTH Consortium, The; Neill, James D.; Barlow, Thomas A.; Martin, Christofer D.; Gezari, Suvi; the GALEX Science Team; Arcavi, Iair; Bloom, Joshua S.; Nugent, Peter E.; Sullivan, Mark; Palomar Transient Factory, The

2016-03-01

The radius and surface composition of an exploding massive star, as well as the explosion energy per unit mass, can be measured using early UV observations of core-collapse supernovae (SNe). We present the first results from a simultaneous GALEX/PTF search for early ultraviolet (UV) emission from SNe. Six SNe II and one Type II superluminous SN (SLSN-II) are clearly detected in the GALEX near-UV (NUV) data. We compare our detection rate with theoretical estimates based on early, shock-cooling UV light curves calculated from models that fit existing Swift and GALEX observations well, combined with volumetric SN rates. We find that our observations are in good agreement with calculated rates assuming that red supergiants (RSGs) explode with fiducial radii of 500 R ⊙, explosion energies of 1051 erg, and ejecta masses of 10 M ⊙. Exploding blue supergiants and Wolf-Rayet stars are poorly constrained. We describe how such observations can be used to derive the progenitor radius, surface composition, and explosion energy per unit mass of such SN events, and we demonstrate why UV observations are critical for such measurements. We use the fiducial RSG parameters to estimate the detection rate of SNe during the shock-cooling phase (<1 day after explosion) for several ground-based surveys (PTF, ZTF, and LSST). We show that the proposed wide-field UV explorer ULTRASAT mission is expected to find >85 SNe per year (˜0.5 SN per deg2), independent of host galaxy extinction, down to an NUV detection limit of 21.5 mag AB. Our pilot GALEX/PTF project thus convincingly demonstrates that a dedicated, systematic SN survey at the NUV band is a compelling method to study how massive stars end their life.

Gas composition of Popocatépetl Volcano between 2007 and 2008: FTIR spectroscopic measurements of an explosive event and during quiescent degassing

NASA Astrophysics Data System (ADS)

Stremme, W.; Ortega, I.; Siebe, C.; Grutter, M.

2011-01-01

On December 1, 2007, the solar absorption infrared spectra of the Popocatépetl volcanic plume was recorded during an eruptive event and complementarily on November 17, 2008, the passive quiescent degassing was measured from the same site. A portable FTIR spectrometer with a scanning mirror for fast tracking of the sun provided the flexibility, quality, and simplicity needed for field deployment. Slant columns of the gases SO 2, HCl, HF, and SiF 4 were retrieved and strong differences could be observed when comparing gas ratios in both time periods. During the explosive eruption, the SO 2/HCl ratio was three times greater and the HF/HCl ratio was slightly smaller than during passive degassing. While the ratios among SO 2, HCl, HF, and SiF 4 describe the chemical composition of the volcanic gas mixture, the SiF 4/HF ratio provides information about the equilibrium temperatures of the stored gases which in this study were calculated at 150° and 185 °C for the explosive and quiescent degassing episodes, respectively. We conclude that cooling of lava domes in the crater precedes Vulcanian explosions as suggested by Schaaf et al (2005). Based on SO 2 flux (Grutter et al., 2008) and measurements and data from the November 2008 event, the average fluxes for HCl, HF, SiF 4, and F through quiescent degassing are estimated to be 204, 22.7, 9.8, and 31.7 tons/day, respectively. These values are similar to those reported by Love et al. (1998) more than 10 yrs ago.

Effects of Heat Treatment on Interface Microstructure and Mechanical Properties of Explosively Welded Ck60/St37 Plates

NASA Astrophysics Data System (ADS)

Yazdani, Majid; Toroghinejad, Mohammad Reza; Hashemi, Seyyed Mohammad

2016-12-01

This study explores the effects of heat treatment on the microstructure and mechanical properties of explosively welded Ck60 steel/St37 steel. The objective is to find an economical way for manufacturing bimetallic plates that can be used in the rolling stand of hot rolling mill units. The explosive ratio and stand-off distance are set at 1.7 and 1.5 t ( t = flyer thickness), respectively. Since explosive welding is accompanied by such undesirable metallurgical effects as remarkable hardening, severe plastic deformation, and even formation of local melted zones near the interface, heat treatment is required to overcome or alleviate these adverse effects. For this purpose, the composites are subjected to heat treatment in a temperature range of 600-700 °C at a rate of 90 °C/h for 1 h. Results demonstrate well-bonded composite plates with a wavy interface. In the as-welded case, vortex zones are formed along the interface; however, they are transformed into fine grains upon heat treatment. Microhardness is also observed to be maximum near the interface in the welded case before it decreases with increasing temperature. Shear strength is the highest in the as-welded specimen, which later decreases as a result of heat treatment. Moreover, the energy absorbed by the heat-treated specimens is observed to increase with increasing temperature so that the lowest value of absorbed energy belongs to the as-welded specimen. Finally, fractography is carried out using the scanning electron microscope to examine the specimens subjected to shear and impact tests. As a result of heat treatment, fracture surfaces exhibit dimpled ruptures and fail in the mixed mode, while failure in the as-welded specimens predominantly occurs in the brittle mode.

On the smell of Composition C-4.

PubMed

Kranz, William; Kitts, Kelley; Strange, Nicholas; Cummins, Joshua; Lotspeich, Erica; Goodpaster, John

2014-03-01

In efforts to locate hidden explosives, humans have had few allies as valuable as the explosives-detecting canine. The unrivaled sensitivity and selectivity of the canine nose have combined to make these animals an attractive choice for law enforcement, military, and private security applications. Although the efficacy of trained detector dogs is well-established, the question of which chemical compounds are responsible for causing a dog to recognize a particular odor and alert to it remains a subject of debate for several explosive formulations--including, perhaps most notably, Composition C-4. Previous studies have indicated that cyclohexanone, 2,3-dimethyl-2,3-dinitrobutane, and 2-ethyl-1-hexanol are the chemicals that may cause canines to alert to C-4. This has led to the suggestion that these substances could be used as a substitute for genuine C-4 in the training, testing, and maintenance of explosives-detecting canines. In this paper, we present an alternative view. Using gas chromatography-mass spectrometry with solid phase microextraction as a pre-concentration technique, we have discovered that 2-ethyl-1-hexanol off-gasses not only from C-4, but also from benign sources, such as the common plasticizers bis(2-ethylhexyl)adipate, bis(2-ethylhexyl)sebacate, and bis(2-ethylhexyl)phthalate; as well as several plasticized items common to our everyday world, including PVC tile, PVC pipe, electrical tape, and credit cards. This observation may potentially discourage the use of 2-ethyl-1-hexanol for training purposes. We also present the results of our own canine field trials focused on the detection of C-4. Through the use of contingency tables and statistical testing, we demonstrate the failure of trained law enforcement dogs in our study to respond in any significant way to these potential odor compounds. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Eruption dynamics and explosive-effusive transitions during the 1400 cal BP eruption of Opala volcano, Kamchatka, Russia

NASA Astrophysics Data System (ADS)

Andrews, Benjamin J.; Dufek, Josef; Ponomareva, Vera

2018-05-01

Deposits and pumice from the 1400 cal BP eruption of Opala volcano record activity that occurred at the explosive-effusive transition, resulting in intermittent, or stop-start, behavior, where explosive activity resumed following a pause. The eruption deposited distinctive, biotite-bearing rhyolite tephra across much of Kamchatka, and its stratigraphy consists of a lithic-rich pumice fall, overlain by pumice falls and pyroclastic density deposits, with the proportion of the latter increasing with height. This sequence repeats such that the middle of the total deposit is marked by a lithic-rich fall with abundant obsidian clasts. Notably, the eruptive pumice are poorly vesiculated, with vesicle textures that record fragmentation of a partially collapsed magmatic foam. The eruption vent, Baranii Amphitheater is filled with obsidian lavas of the same composition as the rhyolite tephra. Based upon the stratigraphic and compositional relations, we divide the eruption into four phases. Phase I initiated with eruption of a lithic-rich pumice fall, followed by eruption of Plinian falls and pyroclastic density currents. During Phase II, the eruption paused for at least 5-6 h; in this time, microlites nucleated and began to grow in the magma. Phase III essentially repeated the Phase I sequence. Obsidian lavas were emplaced during Phase IV. The pumice textures suggest that the magma ascended very near the threshold decompression rate for the transition between explosive (fast) and effusive (slow) behavior. The pause during Phase II likely occurred as decompression slowed enough for the magma to develop sufficient permeability for gas to escape resulting in collapse of the magmatic foam, stopping the eruption and temporarily sealing the conduit. After about 5-6 h, eruption resumed with, once again, magma decompressing very near the explosive-effusive transition. Phase III ended when the decompression rate slowed and lava dome emplacement began. Distributions of pumice and lithic clasts, and inclusion of data from previous workers, indicate minimum deposit volumes of 0.75 and 0.75-1.15 km3 (DRE) and eruption column heights of 18 and 20 km for Phases I and III, respectively. Phases I-III had a likely total duration of 60-80 h, including a pause in activity of 5-6 h during Phase II. This study demonstrates that analysis of vesicle textures from numerous pumice combined with stratigraphic data can reveal syn-eruptive changes in and links between magma permeability, decompression rate, and eruption style. OP-22-Pum is a typical Opala pumice. XRCT scans reveal that vesicles in pumice without obvious banding in hand sample are highly elongate and strongly aligned in different regions. The first half of the animation shows vesicles (white) and the second half shows the solid portions of the pumice (yellow). The field of view is 930 × 930 × 520 μm. OP-22-PumGlass is a pumice with alternating glassy and pumiceous domains. XRCT scans show that the glassy regions contain only small, sparse vesicles, whereas the pumiceous regions comprise elongate, aligned, and interconnected vesicles. The white domains are vesicles. The field of view is 1300 × 1950 × 520 μm.

Advances in explosives analysis—part II: photon and neutron methods

DOE PAGES

Brown, Kathryn E.; Greenfield, Margo T.; McGrane, Shawn D.; ...

2015-10-07

The number and capability of explosives detection and analysis methods have increased dramatically since publication of the Analytical and Bioanalytical Chemistry special issue devoted to Explosives Analysis [Moore DS, Goodpaster JV, Anal Bioanal Chem 395:245–246, 2009]. Here we review and critically evaluate the latest (the past five years) important advances in explosives detection, with details of the improvements over previous methods, and suggest possible avenues towards further advances in, e.g., stand-off distance, detection limit, selectivity, and penetration through camouflage or packaging. Our review consists of two parts. Part I discussed methods based on animals, chemicals (including colorimetry, molecularly imprinted polymers,more » electrochemistry, and immunochemistry), ions (both ion-mobility spectrometry and mass spectrometry), and mechanical devices. In Part II, we review methods based on photons, from very energetic photons including X-rays and gamma rays down to the terahertz range, and neutrons.« less

Line-imaging velocimetry for observing spatially heterogeneous mechanical and chemical responses in plastic bonded explosives during impact.

PubMed

Bolme, C A; Ramos, K J

2013-08-01

A line-imaging velocity interferometer was implemented on a single-stage light gas gun to probe the spatial heterogeneity of mechanical response, chemical reaction, and initiation of detonation in explosives. The instrument is described in detail, and then data are presented on several shock-compressed materials to demonstrate the instrument performance on both homogeneous and heterogeneous samples. The noise floor of this diagnostic was determined to be 0.24 rad with a shot on elastically compressed sapphire. The diagnostic was then applied to two heterogeneous plastic bonded explosives: 3,3(')-diaminoazoxyfurazan (DAAF) and PBX 9501, where significant spatial velocity heterogeneity was observed during the build up to detonation. In PBX 9501, the velocity heterogeneity was consistent with the explosive grain size, however in DAAF, we observed heterogeneity on a much larger length scale than the grain size that was similar to the imaging resolution of the instrument.

Line-imaging velocimetry for observing spatially heterogeneous mechanical and chemical responses in plastic bonded explosives during impact

NASA Astrophysics Data System (ADS)

Bolme, C. A.; Ramos, K. J.

2013-08-01

A line-imaging velocity interferometer was implemented on a single-stage light gas gun to probe the spatial heterogeneity of mechanical response, chemical reaction, and initiation of detonation in explosives. The instrument is described in detail, and then data are presented on several shock-compressed materials to demonstrate the instrument performance on both homogeneous and heterogeneous samples. The noise floor of this diagnostic was determined to be 0.24 rad with a shot on elastically compressed sapphire. The diagnostic was then applied to two heterogeneous plastic bonded explosives: 3,3'-diaminoazoxyfurazan (DAAF) and PBX 9501, where significant spatial velocity heterogeneity was observed during the build up to detonation. In PBX 9501, the velocity heterogeneity was consistent with the explosive grain size, however in DAAF, we observed heterogeneity on a much larger length scale than the grain size that was similar to the imaging resolution of the instrument.

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.

Upon the reconstruction of accidents triggered by tire explosion. Analytical model and case study

NASA Astrophysics Data System (ADS)

Gaiginschi, L.; Agape, I.; Talif, S.

2017-10-01

Accident Reconstruction is important in the general context of increasing road traffic safety. In the casuistry of traffic accidents, those caused by tire explosions are critical under the severity of consequences, because they are usually happening at high speeds. Consequently, the knowledge of the running speed of the vehicle involved at the time of the tire explosion is essential to elucidate the circumstances of the accident. The paper presents an analytical model for the kinematics of a vehicle which, after the explosion of one of its tires, begins to skid, overturns and rolls. The model consists of two concurent approaches built as applications of the momentum conservation and energy conservation principles, and allows determination of the initial speed of the vehicle involved, by running backwards the sequences of the road event. The authors also aimed to both validate the two distinct analytical approaches by calibrating the calculation algorithms on a case study

Advances in explosives analysis—part I. animal, chemical, ion, and mechanical methods

DOE PAGES

Brown, Kathryn E.; Greenfield, Margo T.; McGrane, Shawn D.; ...

2015-10-13

The number and capability of explosives detection and analysis methods have increased substantially since the publication of the Analytical and Bioanalytical Chemistry special issue devoted to Explosives Analysis (Moore and Goodpaster, Anal Bioanal Chem 395(2):245–246, 2009). We review and critically evaluate the latest (the past five years) important advances in explosives detection, with details of the improvements over previous methods, and suggest possible avenues towards further advances in, e.g., stand-off distance, detection limit, selectivity, and penetration through camouflage or packaging. The review consists of two parts. Moreover, Part I, reviews methods based on animals, chemicals (including colorimetry, molecularly imprinted polymers,more » electrochemistry, and immunochemistry), ions (both ion-mobility spectrometry and mass spectrometry), and mechanical devices. Part II will review methods based on photons, from very energetic photons including X-rays and gamma rays down to the terahertz range, and neutrons.« less

Estimating explosion properties of normal hydrogen-rich core-collapse supernovae

NASA Astrophysics Data System (ADS)

Pejcha, Ondrej

2017-08-01

Recent parameterized 1D explosion models of hundreds of core-collapse supernova progenitors suggest that success and failure are intertwined in a complex pattern that is not a simple function of the progenitor initial mass. This rugged landscape is present also in other explosion properties, allowing for quantitative tests of the neutrino mechanism from observations of hundreds of supernovae discovered every year. We present a new self-consistent and versatile method that derives photospheric radius and temperature variations of normal hydrogen-rich core-collapse supernovae based on their photometric measurements and expansion velocities. We construct SED and bolometric light curves, determine explosion energies, ejecta and nickel masses while taking into account all uncertainties and covariances of the model. We describe the efforts to compare the inferences to the predictions of the neutrino mechanim. The model can be adapted to include more physical assumptions to utilize primarily photometric data coming from surveys such as LSST.

Cylinder Test Specification

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

Richard Catanach; Larry Hill; Herbert Harry

1999-10-01

The purpose of the cylinder testis two-fold: (1) to characterize the metal-pushing ability of an explosive relative to that of other explosives as evaluated by the E{sub 19} cylinder energy and the G{sub 19} Gurney energy and (2) to help establish the explosive product equation-of-state (historically, the Jones-Wilkins-Lee (JWL) equation). This specification details the material requirements and procedures necessary to assemble and fire a typical Los Alamos National Laboratory (LANL) cylinder test. Strict adherence to the cylinder. material properties, machining tolerances, material heat-treatment and etching processes, and high explosive machining tolerances is essential for test-to-test consistency and to maximize radialmore » wall expansions. Assembly and setup of the cylinder test require precise attention to detail, especially when placing intricate pin wires on the cylinder wall. The cylinder test is typically fired outdoors and at ambient temperature.« less

Verification of Disarmament or Limitation of Armaments: Instruments, Negotiations, Proposals

DTIC Science & Technology

1992-05-01

explosions and may complicate the process of detection. An even greater difficulty faced by seismologists is the ambient background of seismic "noise...suspected event would be a complex operation. It would consist of surveys of the area of the presumed nuclear explosion in order to measure ambient ...Draft Resolution to the OAS General Assembly, June 1991 and OAS Resolution "Cooperacion para la seguridad en el hemisferio. Limitacion de la

High explosive compound

DOEpatents

Crawford, Theodore C.

1976-01-01

1. A low detonation velocity explosive consisting essentially of a particulate mixture of ortho-boric acid and trinitrotoluene, said mixture containing from about 25 percent to about 65 percent by weight of ortho-boric acid, said ortho-boric acid comprised of from 60 percent to 90 percent of spherical particles having a mean particle size of about 275 microns and 10 percent to 40 percent of spherical particles having a particle size less than about 44 microns.

Explosive Infrasonic Events: Sensor Comparison Experiment (SCE)

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

Schnurr, J. M.; Garces, M.; Rodgers, A. J.

SCE (sensor comparison experiment) 1 through 4 consists of a series of four controlled above-ground explosions designed to provide new data for overpressure propagation. Infrasound data were collected by LLNL iPhones and other sensors. Origin times, locations HOB, and yields are not being released at this time and are therefore not included in this report. This preliminary report will be updated as access to additional data changes, or instrument responses are determined.

Identification and evolution of the juvenile component in 2004-2005 Mount St. Helens ash: Chapter 29 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

USGS Publications Warehouse

Rowe, Michael C.; Thornber, Carl R.; Kent, Adam J.R.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

2008-01-01

Petrologic studies of volcanic ash are commonly used to identify juvenile volcanic material and observe changes in the composition and style of volcanic eruptions. During the 2004-5 eruption of Mount St. Helens, recognition of the juvenile component in ash produced by early phreatic explosions was complicated by the presence of a substantial proportion of 1980-86 lava-dome fragments and glassy tephra, in addition to older volcanic fragments possibly derived from crater debris. In this report, we correlate groundmass textures and compositions of glass, mafic phases, and feldspar from 2004-5 ash in an attempt to identify juvenile material in early phreatic explosions and to distinguish among the various processes that generate and distribute ash. We conclude that clean glass in the ash is derived mostly from nonjuvenile sources and is not particularly useful for identifying the proportion of juvenile material in ash samples. High Li contents (>30 μg/g) in feldspars provide a useful tracer for juvenile material and suggest an increase in the proportion of the juvenile component between October 1 and October 4, 2004, before the emergence of hot dacite on the surface of the crater on October 11, 2004. The presence of Li-rich feldspar out of equilibrium (based on Liplagioclase/melt partitioning) with groundmass and bulk dacite early in the eruption also suggests vapor enrichment in the initially erupted dacite. If an excess vapor phase was, indeed, present, it may have provided a catalyst to initiate the eruption. Textural and compositional comparisons between dome fault gouge and the ash produced by rockfalls, rock avalanches, and vent explosions indicate that the fault gouge is a likely source of ash particles for both types of events. Comparison of the ash from vent explosions and rockfalls suggests that the fault gouge and new dome were initially heterogeneous, containing a mixture of conduit and crater debris and juvenile material, but became increasingly homogeneous, dominated by juvenile material, by early January 2005.

The hard start phenomena in hypergolic engines. Volume 5: RCS engine deformation and destruct tests

NASA Technical Reports Server (NTRS)

Miron, Y.; Perlee, H. E.

1974-01-01

Tests were conducted to determine the causes of Apollo Reaction Control (RCS) engine failures. Stainless steel engines constructed for use in the destructive tests are described. The tests conducted during the three phase investigation are discussed. It was determined that the explosive reaction that destroys the RCS engines occurs at the time of engine ignition and is apparently due to either the detonation of the heterogeneous constituents of the rocket engine, consisting primarily of unreacted propellant droplets and vapors, and/or the detonation of explosive materials accumulated on the engine walls from previous pulses. Photographs of the effects of explosions on the simulated RCS engines are provided.

A facies model for a quaternary andesitic composite volcano: Ruapehu, New Zealand

NASA Astrophysics Data System (ADS)

Hackett, W. R.; Houghton, B. F.

1989-01-01

Ruapehu composite volcano is a dynamic volcanic-sedimentary system, characterised by high accumulation rates and by rapid lateral and vertical change in facies. Four major cone-building episodes have occurred over 250 Ka, from a variety of summit, flank and satellite vents. Eruptive styles include subplinian, strombolian, phreatomagmatic, vulcanian and dome-related explosive eruptions, and extrusion of lava flows and domes. The volcano can be divided into two parts: a composite cone of volume 110 km3, surrounded by an equally voluminous ring plain. Complementary portions of Ruapehu's history are preserved in cone-forming and ring plain environments. Cone-forming sequences are dominated by sheet- and autobrecciated-lava flows, which seldom reach the ring plain. The ring plain is built predominantly from the products of explosive volcanism, both the distal primary pyroclastic deposits and the reworked material eroded from the cone. Much of the material entering the ring plain is transported by lahars either generated directly by eruptions or triggered by the high intensity rain storms which characterise the region. Ring plain detritus is reworked rapidly by concentrated and hyperconcentrated streams in pulses of rapid aggradation immediately following eruptions and more gradually in the longer intervals between eruptions.

Explosive vapor detection payload for small robots

NASA Astrophysics Data System (ADS)

Stimac, Phil J.; Pettit, Michael; Wetzel, John P.; Haas, John W.

2013-05-01

Detection of explosive hazards is a critical component of enabling and improving operational mobility and protection of US Forces. The Autonomous Mine Detection System (AMDS) developed by the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) is addressing this challenge for dismounted soldiers. Under the AMDS program, ARA has developed a vapor sampling system that enhances the detection of explosive residues using commercial-off-the-shelf (COTS) sensors. The Explosives Hazard Trace Detection (EHTD) payload is designed for plug-and-play installation and operation on small robotic platforms, addressing critical Army needs for more safely detecting concealed or exposed explosives in areas such as culverts, walls and vehicles. In this paper, we describe the development, robotic integration and performance of the explosive vapor sampling system, which consists of a sampling "head," a vapor transport tube and an extendable "boom." The sampling head and transport tube are integrated with the boom, allowing samples to be collected from targeted surfaces up to 7-ft away from the robotic platform. During sample collection, an IR lamp in the sampling head is used to heat a suspected object/surface and the vapors are drawn through the heated vapor transport tube to an ion mobility spectrometer (IMS) for detection. The EHTD payload is capable of quickly (less than 30 seconds) detecting explosives such as TNT, PETN, and RDX at nanogram levels on common surfaces (brick, concrete, wood, glass, etc.).

Simple multispectral imaging approach for determining the transfer of explosive residues in consecutive fingerprints.

PubMed

Lees, Heidi; Zapata, Félix; Vaher, Merike; García-Ruiz, Carmen

2018-07-01

This novel investigation focused on studying the transfer of explosive residues (TNT, HMTD, PETN, ANFO, dynamite, black powder, NH 4 NO 3 , KNO 3 , NaClO 3 ) in ten consecutive fingerprints to two different surfaces - cotton fabric and polycarbonate plastic - by using multispectral imaging (MSI). Imaging was performed employing a reflex camera in a purpose-built photo studio. Images were processed in MATLAB to select the most discriminating frame - the one that provided the sharpest contrast between the explosive and the material in the red-green-blue (RGB) visible region. The amount of explosive residues transferred in each fingerprint was determined as the number of pixels containing explosive particles. First, the pattern of PETN transfer by ten different persons in successive fingerprints was studied. No significant differences in the pattern of transfer of PETN between subjects were observed, which was also confirmed by multivariate analysis of variance (MANOVA). Then, the transfer of traces of the nine above explosives in ten consecutive fingerprints to cotton fabric and polycarbonate plastic was investigated. The obtained results demonstrated that the amount of explosive residues deposited on successive fingerprints tended to undergo a power or exponential decrease, with the exception of inorganic salts (NH 4 NO 3 , KNO 3 , NaClO 3 ) and ANFO (consists of 90% NH 4 NO 3 ). Copyright © 2018 Elsevier B.V. All rights reserved.

Pushing the Volcanic Explosivity Index to its limit and beyond: Constraints from exceptionally weak explosive eruptions at Kīlauea in 2008

USGS Publications Warehouse

Houghton, Bruce F.; Swanson, Don; Rausch, J.; Carey, R.J.; Fagents, S.A.; Orr, Tim R.

2013-01-01

Estimating the mass, volume, and dispersal of the deposits of very small and/or extremely weak explosive eruptions is difficult, unless they can be sampled on eruption. During explosive eruptions of Halema‘uma‘u Crater (Kīlauea, Hawaii) in 2008, we constrained for the first time deposits of bulk volumes as small as 9–300 m3 (1 × 104 to 8 × 105 kg) and can demonstrate that they show simple exponential thinning with distance from the vent. There is no simple fit for such products within classifications such as the Volcanic Explosivity Index (VEI). The VEI is being increasingly used as the measure of magnitude of explosive eruptions, and as an input for both hazard modeling and forecasting of atmospheric dispersal of tephra. The 2008 deposits demonstrate a problem for the use of the VEI, as originally defined, which classifies small, yet ballistic-producing, explosive eruptions at Kīlauea and other basaltic volcanoes as nonexplosive. We suggest a simple change to extend the scale in a fashion inclusive of such very small deposits, and to make the VEI more consistent with other magnitude scales such as the Richter scale for earthquakes. Eruptions of this magnitude constitute a significant risk at Kīlauea and elsewhere because of their high frequency and the growing number of “volcano tourists” visiting basaltic volcanoes.

Energetic Trend in Explosive Activity of Stromboli

NASA Astrophysics Data System (ADS)

Coltelli, M.; Cristaldi, A.; Mangiagli, S.; Nunnari, G.; Pecora, E.

2003-12-01

The typical activity of Stromboli consists of intermittent mild explosions lasting a few seconds, which take place at different vents and at variable intervals, the most common time interval being 10-20 minutes. However, the routine activity can be interrupted by more violent, paroxysmal explosions, that eject m-sized scoriaceous bombs and lava blocks to a distance of several hundreds of meters from the craters, endangering the numerous tourists that watch the spectacular activity from the volcano's summit located about two hundreds meters from the active vents. On average, 1-2 paroxysmal explosions occurred per year over the past century, but this statistic may be underestimated in absence of continuous monitoring. For this reason from summer 1996 a remote surveillance camera works on Stromboli recording continuously the volcanic activity. It is located on Pizzo Sopra la Fossa, 100 metres above the crater terrace where are the active vents. Using image analysis we seeks to identify any change of the explosive activity trend that could precede a particular eruptive event, like paroxysmal explosions, fire fountains, lava flows. The analysis include the counting of the explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetics energy. Associating at each class a corresponding Index of energy in order to compute an heuristic value of the Average Daily Energy Released (ADER) of the explosive activity at Stromboli and plotting this value for each crater versus time, the diagram shows a cyclic behavior with max and min of explosive activity ranging from a few days to a month. Often the craters show opposite trends so when the activity decreases in a crater, increases in the other. Before every paroxysmal explosions recorded, the crater that produced the event decreased and then stopped its activity from a few days to weeks before. The other crater tried to compensate increasing its activity and when it declined the paroxysmal explosion occurred suddenly at the former site. From September 2001 an on-line image analyzer called VAMOS (Volcanic Activity MOnitoring System) operates detection and classification of explosive events in real-time. The system has automatically recorded and analyzed the change in the energetic trend that preceded the 20 October 2001 paroxysmal explosion that killed a woman and the strong explosive activity that preceded the onset of 28 December 2002 lava flow eruption.

Yields of Soviet underground nuclear explosions at Novaya Zemlya, 1964-1976, from seismic body and surface waves

PubMed Central

Sykes, Lynn R.; Wiggins, Graham C.

1986-01-01

Surface and body wave magnitudes are determined for 15 U.S.S.R. underground nuclear weapons tests conducted at Novaya Zemlya between 1964 and 1976 and are used to estimate yields. These events include the largest underground explosions detonated by the Soviet Union. A histogram of body wave magnitude (mb) values indicates a clustering of explosions at a few specific yields. The most pronounced cluster consists of six explosions of yield near 500 kilotons. Several of these seem to be tests of warheads for major strategic systems that became operational in the late 1970s. The largest Soviet underground explosion is estimated to have a yield of 3500 ± 600 kilotons, somewhat smaller than the yield of the largest U.S. underground test. A preliminary estimation of the significance of tectonic release is made by measuring the amplitude of Love waves. The bias in mb for Novaya Zemlya relative to the Nevada test site is about 0.35, nearly identical to that of the eastern Kazakhstan test site relative to Nevada. PMID:16593645

Geochemistry of glass and olivine from Keanakako`i Tephra at Kilauea Volcano, Hawai`i

NASA Astrophysics Data System (ADS)

Garcia, M. O.; Mucek, A. E.; Swanson, D.

2011-12-01

Kilauea Volcano is well known for its frequent quiescent eruptions. However, it also has an underappreciated explosive past. Recent field work has documented many details of the Keanakako`i Tephra, which was generated during a period of explosive activity when few lava flows were erupted. The dominantly phreatomagmatic eruptions, which produced the Keanakako`i Tephra, began late in, or completely after, the formation of Kilauea Caldera (ca. 1500 CE) and continued sporadically until 1823. Thereafter, effusive eruptions outside the caldera resumed and have continued to the present.The Keanakako`i deposits provide an opportunity to examine the restoration of Kilauea's magmatic plumbing following caldera formation. Glassy products with variable amounts of olivine dominate from ca. 1500 A.D. to the late 1600 A.D., whereas lithic-rich deposits with sparse glass are common in the 1700 A.D. deposits, which include the deadly explosive activity of A.D. 1790. Glass compositions from tephra and basalt flows show remarkable MgO variations (4-11 wt percent), larger than those observed in glasses from subsequent eruptions. Some units have variable MgO indicating a zoned magma reservoir, whereas some others have variable incompatible element ratios suggesting magma mixing. The highest MgO values (>10 wt percent) are from 1500 A.D. and 1823 deposits. The range of parental magma compositions based on tephra glasses erupted over a 300 year period is comparable to those observed for the first 15 years of the Pu`u `O`o eruption and about half of the variation observed for summit eruptions from 1832 to 1982. The limited range in tephra parental magma compositions may be related to a lower magma production rate during the period the tephra was erupted.

Radiographic measurements of viscosity in Comp B

NASA Astrophysics Data System (ADS)

Oschwald, Dave; Suvorova, Natalya; Remelius, Dennis; Henson, Bryan; Smilowitz, Laura

2017-06-01

Experiments were preformed using standard Composition B which is an explosive consisting of castable mixtures of RDX and TNT. Comp B is most commonly described as 60/40 RDX/TNT. This material was pressed into cylindrical samples with a spherical bead of various materials imbedded into the center. The samples were then incased into aluminum tubes that were wrapped in heat tape for external heating. A table top CW X-ray system coupled with a scintillator/camera system was used to observe the heating process and the time to temperature where the bead started to move inside the melt of the TNT due to gravity. These experiments where aiming to measure viscosity of Comp B versus temperature. The beads embedded into the pellets were made of various materials and differ in density and sizes to increase accuracy of the viscosity measurements. This work will focus on the experimental set-up and the suite of diagnostic used in these experiments.

An Analysis of Shock-Compression in Mo-Si Powder Mixtures Using Recovery and Time-Resolved Measurements

NASA Astrophysics Data System (ADS)

Vandersall, Kevin S.; Thadhani, Naresh N.

1999-06-01

The densification and reaction characteristics in the Mo-Si system were investigated utilizing recovery experiments as well as time resolved measurements with in-situ stress gages. The starting sample in all cases consisted of statically pressed Mo + 2 Si powder mixtures ( ~55% TMD). The recovery experiments were performed using the Sandia Momma Bear and Momma Bear A fixtures with baratol and composition B explosives respectively. The instrumented experiments were performed in a capsule design similar to that of the Momma Bear, but modified to incorporate poly-vinyl di-flouride (PVDF) stress gages at the front and rear surfaces of the powder. These experiments were performed using a single stage gas gun in the velocity range of 500 m/s to 1 km/s. The instrumented experiments allow the crush strength, densification history, and reaction threshold to be mapped at increasing pressure to correlate with reaction observed in the recovery experiments.

Deaggregation, Modification, and Developing Applications for Detonation Nanodiamond

NASA Astrophysics Data System (ADS)

Mochalin, Vadym

2017-06-01

Nanodiamond powder (ND) is one of the most promising materials for advanced composites and biomedical applications. It is also a commercial precursor for carbon nanoonions - material for high power micrometer size supercapacitors and potentially, Li-ion batteries. ND is produced by detonation of explosives with negative oxygen balance in a closed chamber, where extremely high pressures and temperatures develop during detonation. ND consists of diamond particles of 5 nm diameter, combining fully accessible large surface and rich and tailorable surface chemistry. ND has unique properties including optical, electrical, thermal, and mechanical, and is biocompatible and non-toxic. Due to numerous surface functional groups, ND has catalytic and electrochemical activity. Several techniques have been proposed for ND deaggregation based on milling with costly ceramic microbeads, leaving difficult to remove contaminations in the resulting ND suspension. We have recently discovered a novel, green technique for ND deaggregation using sonication in aqueous sodium chloride slurry. Upon completion of the process sodium chloride can be easily washed out with water leaving behind no contaminants and yielding stable single-digit ND colloids. Modification and development of applications for ND in composites, drug delivery, biomedical imaging, etc., will be also discussed.

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-04-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40M⊙ and initial rotation velocities of 0-450 kms-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-07-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40 M⊙ and initial rotation velocities of 0-450 km s-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

Can Plume-Forming Asteroid Airbursts Generate Meteotsunami in Deep Water?

NASA Astrophysics Data System (ADS)

Boslough, M.

2015-12-01

Hydrocode simulations suggest that the 1908 Tunguska explosion was a plume-forming airburst analogous to those caused by Comet Shoemaker-Levy 9 (SL9) collisions with Jupiter in 1994. A noctilucent cloud that appeared over Europe following the Tunguska event is similar to post-impact features on Jupiter, consistent with a collapsed plume containing condensation from the vaporized asteroid. Previous workers treated Tunguska as a point explosion and used seismic records, barograms, and extent of fallen trees to determine explosive yield. Estimates were based on scaling laws derived from nuclear weapons data, neglecting directionality, mass, and momentum of the asteroid. This point-source assumption, with other simplifications, led to a significant overestimate. Tunguska seismic data were consistent with ground motion from a vertical point impulse of 7×1018dyn sec caused by the downward blast wave of a 12.5-megaton nuclear explosion at an altitude of 8.5 km for an effective momentum multiplication factor (β) of ~80. However, simulations of a 3-megaton collisional airburst reveal that the upward-directed momentum contained in a ballistic plume can reach this level within the first minute after the explosion (β≈300). The reaction impulse from such an airburst is therefore similar to a much larger non-plume-forming nuclear explosion. Momentum is coupled through the atmosphere to the surface, generating disproportionately large seismic signatures. This result suggests that coupling from an over-water plume-forming airburst could be a more efficient tsunami source mechanism than a collapsing impact cavity or direct air blast because the characteristic time of the plume is closer to that of a long-period wave in deep water. As the plume accelerates upward, it creates a slowly-rising and sustained overpressure with a ramp wave that propagates outward at the speed of sound, generating a tsunami in deep ocean by the same mechanism that yields slower meteotsunami in shallow basins. This hypothesis is consistent with the observation of prominent internal waves observed propagating radially outward from several SL9 impacts, even though the waves were not in Proudman resonance. Because of slow compression, the SL9 waves grew with a Froude number of ~1.6, the same as that of the sound speed in air over ~4.6-km-deep water.

Steady-state shock-driven reactions in mixtures of nano-sized aluminum and dilute hydrogen peroxide

DOE PAGES

Schmitt, Matthew Mark; Bowden, Patrick Robert; Tappan, Bryce C.; ...

2017-09-21

Mixtures of nanoaluminum (nAl) and dilute hydrogen peroxide (HP) were studied to determine their potential to detonate when subjected to explosive shock. Results of explosively driven rate stick experiments revealed steady shock propagation for stoichiometric mixtures of nAl and 10 wt% HP. The critical diameter of this composition is estimated to be between 27.7 and 34.5 mm. Detonation velocities between 3.034 and 3.187 mm/μs were obtained, varying with charge diameter and density. Furthermore this represents the first measured shock-driven, self-sustained reaction in nAl and dilute HP mixtures.

Shock-to-detonation transition of RDX, HMX and NTO based composite high explosives: experiments and modelling

NASA Astrophysics Data System (ADS)

Baudin, G.; Roudot, M.; Genetier, M.; Mateille, P.; Lefrançois, A.

2014-05-01

HMX, RDX and NTO based cast-cured plastic bounded explosive (PBX) are widely used in insensitive ammunitions. Designing modern warheads needs robust and reliable models to compute shock ignition and detonation propagation inside PBX. Comparing to a pressed PBX, a cast-cured PBX is not porous and the hot-spots are mainly located at the grain-binder interface leading to a different burning behavior during shock-to-detonation transition. Here, we review the shock-to-detonation transition (SDT) and its modeling for cast-cured PBX containing HMX, RDX and NTO. Future direction is given in conclusion.

SUPERFUND TREATABILITY CLEARINGHOUSE: COMPOSITING OF EXPLOSIVES

EPA Science Inventory

This treatability study was conducted by Atlantic Research Corporation for the U.S. Army Toxic and Hazardous Material Agency. The objective of this bench-scale study was to determine the extent to which TNT and RDX concentrations were reduced by composting for a six week peri...

Quantum Dot and Polymer Composite Cross-Reactive Array for Chemical Vapor Detection.

PubMed

Bright, Collin J; Nallon, Eric C; Polcha, Michael P; Schnee, Vincent P

2015-12-15

A cross-reactive chemical sensing array was made from CdSe Quantum Dots (QDs) and five different organic polymers by inkjet printing to create segmented fluorescent composite regions on quartz substrates. The sensor array was challenged with exposures from two sets of analytes, including one set of 14 different functionalized benzenes and one set of 14 compounds related to security concerns, including the explosives trinitrotoluene (TNT) and ammonium nitrate. The array was broadly responsive to analytes with different chemical functionalities due to the multiple sensing mechanisms that altered the QDs' fluorescence. The sensor array displayed excellent discrimination between members within both sets. Classification accuracy of more than 93% was achieved, including the complete discrimination of very similar dinitrobenzene isomers and three halogenated, substituted benzene compounds. The simple fabrication, broad responsivity, and high discrimination capacity of this type of cross-reactive array are ideal qualities for the development of sensors with excellent sensitivity to chemical and explosive threats while maintaining low false alarm rates.

Synthesis and characterization of magnetic of Ni/ABS nanocomposites by electrical explosion of wire in liquid and solution blending methods

NASA Astrophysics Data System (ADS)

Thuyet-Nguyen, Minh; Hai-Nguyen, Hong; Kim, Won Joo; Kim, Ho Yoon; Kim, Jin-Chun

2017-03-01

Nanomaterials have attracted great attention from chemists, physicists and materials scientists because of their application benefits and special properties. Thermoplastics have been used in many applications such as molding of non-electrical components, conducting, magnetic field and 3D printing. Nanocomposites are known as a material which blends the best properties of components, a high performance material exhibits unusual property combinations and unique design possibilities. In this research, we focused to investigate and report primary results in the synthesis of magnetic nanocomposites based on acrylonitrile butadiene styrene (ABS), which are useful and important thermoplastics. Nickel nanopowder was prepared by electrical explosion of wire in a liquid were used as magnetic component. The composites were prepared by following steps, first the obtained Ni nanopowders were incorporated into the ABS matrix via a solution blending method (drop-casting), and then the solvent was evaporated. The characterizations of obtaining composites were analyzed by field emission scanning electron microscopy, X-Ray Diffraction analysis and vibrating sample magnetometer.

Vertically Integrated MEMS SOI Composite Porous Silicon-Crystalline Silicon Cantilever-Array Sensors: Concept for Continuous Sensing of Explosives and Warfare Agents

NASA Astrophysics Data System (ADS)

Stolyarova, Sara; Shemesh, Ariel; Aharon, Oren; Cohen, Omer; Gal, Lior; Eichen, Yoav; Nemirovsky, Yael

This study focuses on arrays of cantilevers made of crystalline silicon (c-Si), using SOI wafers as the starting material and using bulk micromachining. The arrays are subsequently transformed into composite porous silicon-crystalline silicon cantilevers, using a unique vapor phase process tailored for providing a thin surface layer of porous silicon on one side only. This results in asymmetric cantilever arrays, with one side providing nano-structured porous large surface, which can be further coated with polymers, thus providing additional sensing capabilities and enhanced sensing. The c-Si cantilevers are vertically integrated with a bottom silicon die with electrodes allowing electrostatic actuation. Flip Chip bonding is used for the vertical integration. The readout is provided by a sensitive Capacitance to Digital Converter. The fabrication, processing and characterization results are reported. The reported study is aimed towards achieving miniature cantilever chips with integrated readout for sensing explosives and chemical warfare agents in the field.

P sub n from the Nevada Test Site

DTIC Science & Technology

1988-12-15

reviewed and is approved for publication" JAMES0- t1IC Z--C J (TEX S C. BAkTIS CnLract Manager Acting Chief Solid Earth Geophysics Branch Solid Earth...high frequency Pn . The data base being used in the development consists of signals from explosions and earthquakes recorded on the western U.S. digital...measured quantitatively by correlating the average explosiorn ?n trace wiLh a data base of explosion and earthquake signals. The populations

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

Carmichael, Joshua D.; Hartse, Hans

Colocated explosive sources often produce correlated seismic waveforms. Multichannel correlation detectors identify these signals by scanning template waveforms recorded from known reference events against "target" data to find similar waveforms. This screening problem is challenged at thresholds required to monitor smaller explosions, often because non-target signals falsely trigger such detectors. Therefore, it is generally unclear what thresholds will reliably identify a target explosion while screening non-target background seismicity. Here, we estimate threshold magnitudes for hypothetical explosions located at the North Korean nuclear test site over six months of 2010, by processing International Monitoring System (IMS) array data with a multichannelmore » waveform correlation detector. Our method (1) accounts for low amplitude background seismicity that falsely triggers correlation detectors but is unidentifiable with conventional power beams, (2) adapts to diurnally variable noise levels and (3) uses source-receiver reciprocity concepts to estimate thresholds for explosions spatially separated from the template source. Furthermore, we find that underground explosions with body wave magnitudes m b = 1.66 are detectable at the IMS array USRK with probability 0.99, when using template waveforms consisting only of P -waves, without false alarms. We conservatively find that these thresholds also increase by up to a magnitude unit for sources located 4 km or more from the Feb.12, 2013 announced nuclear test.« less

The Synthesis of 44Ti and 56Ni in Massive Stars

NASA Astrophysics Data System (ADS)

Chieffi, Alessandro; Limongi, Marco

2017-02-01

We discuss the influence of rotation on the combined synthesis of {}44{Ti} and {}56{Ni} in massive stars. While {}56{Ni} is significantly produced by both complete and incomplete explosive Si burning, {}44{Ti} is mainly produced by complete explosive Si burning, with a minor contribution (in standard non-rotating models) from incomplete explosive Si burning and O burning (both explosive and hydrostatic). We find that, in most cases, the thickness of the region exposed to incomplete explosive Si burning increases in rotating models (initial velocity, v ini = 300 km s-1) and since {}56{Ni} is significantly produced in this zone, the fraction of mass coming from the complete explosive Si burning zone necessary to get the required amount of {}56{Ni} reduces. Therefore the amount of {}44{Ti} ejected for a given fixed amount of {}56{Ni} decreases in rotating models. However, some rotating models at [Fe/H] = -1 develop a very extended O convective shell in which a consistent amount of {}44{Ti} is formed, preserved, and ejected in the interstellar medium. Hence a better modeling of the thermal instabilities (convection) in the advanced burning phases together with a critical analysis of the cross sections of the nuclear reactions operating in O burning are relevant for the understanding of the synthesis of {}44{Ti}.

Sorbent Film-Coated Passive Samplers for Explosives Vapour Detection Part A: Materials Optimisation and Integration with Analytical Technologies.

PubMed

McEneff, Gillian L; Murphy, Bronagh; Webb, Tony; Wood, Dan; Irlam, Rachel; Mills, Jim; Green, David; Barron, Leon P

2018-04-11

A new thin-film passive sampler is presented as a low resource dependent and discrete continuous monitoring solution for explosives-related vapours. Using 15 mid-high vapour pressure explosives-related compounds as probes, combinations of four thermally stable substrates and six film-based sorbents were evaluated. Meta-aramid and phenylene oxide-based materials showed the best recoveries from small voids (~70%). Analysis was performed using liquid chromatography-high resolution accurate mass spectrometry which also enabled tentative identification of new targets from the acquired data. Preliminary uptake kinetics experiments revealed plateau concentrations on the device were reached between 3-5 days. Compounds used in improvised explosive devices, such as triacetone triperoxide, were detected within 1 hour and were stably retained by the sampler for up to 7 days. Sampler performance was consistent for 22 months after manufacture. Lastly, its direct integration with currently in-service explosives screening equipment including ion mobility spectrometry and thermal desorption mass spectrometry is presented. Following exposure to several open environments and targeted interferences, sampler performance was subsequently assessed and potential interferences identified. High-security building and area monitoring for concealed explosives using such cost-effective and discrete passive samplers can add extra assurance to search routines while minimising any additional burden on personnel or everyday site operation.

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

Chiappetta, R.F.

An explosive`s velocity of detonation (VOD), can be used to indicate a number of important characteristics regarding the product`s performance under specific field and test conditions. A number of new characteristic and transient VOD curves have been identified in the field, which can be used to evaluate explosive performance, control ground vibration amplitudes and frequencies, select the correct amount and type of stemming for use at the collar and in stem decks, eliminate explosive desensitization, evaluate primer performance, design air deck based blasts, evaluate contaminated explosives and to overcome post blast noxious fumes. Tests were conducted over a six yearmore » period in single and multi-hole blasts using laboratory and full scale blast environments. Explosives tested ranged from pure Emulsion to Anfo and various grades of Emulsion/Anfo blends. Field test parameters were; borehole diameter (1 1/2--30 inches), hole depths (10--120 feet), primer size (0.5--6.4 pounds) and the blast environment varied from soft, jelly-like tar sands to some of the hardest iron ore formations. Most tests were instrumented with an array of blast monitoring instrumentation systems consisting of continuous velocity of detonation recorders, high-speed 16 mm cameras, laser-surveying instrumentation and seismographs which were placed in the near and far fields.« less

Manipulating explosive sensitivity through structural modifications in a nitrate ester system

NASA Astrophysics Data System (ADS)

Manner, Virginia

2017-06-01

Understanding how condensed phase effects influence sensitivity is essential for developing next generation insensitive high explosives. However, the ability to predictably manipulate explosive sensitivity remains an elusive goal. Explosive sensitivity has been suggested to be governed by multiple factors, from intramolecular effects such as bond dissociation energy, oxygen balance, and the electrostatic potential of reactive functional groups, to larger scale effects, such as crystal structure and hot spot formation. We have developed derivatives of the explosive pentaerythritol tetranitrate (PETN) and examined them experimentally and theoretically, in order to better understand which properties influence sensitivity. With this molecular framework, we can evaluate how small changes to the structure of the molecule influence qualities such as oxygen balance, heat of formation, heat capacity, compressibility, crystal packing, and hydrogen bonding, through techniques such as differential scanning calorimetry, x-ray crystallography, and atomistic simulation. We have also used small-scale sensitivity testing as an initial tool to screen for large and consistent differences in handling sensitivity. We will discuss the many factors that contribute to sensitivity in this series of systematically-modified molecules as well as in existing well-studied explosive systems, such as triaminotrinitrobenzene (TATB) and nitroglycerin (NG). In collaboration with: Thomas Myers, Marc Cawkwell, Edward Kober, Bryce Tappan, Geoffrey Brown, Mary Sandstrom, LOS ALAMOS NATL LAB.

Seismic Imaging of the Source Physics Experiment Site with the Large-N Seismic Array

NASA Astrophysics Data System (ADS)

Chen, T.; Snelson, C. M.; Mellors, R. J.

2017-12-01

The Source Physics Experiment (SPE) consists of a series of chemical explosions at the Nevada National Security Site. The goal of SPE is to understand seismic wave generation and propagation from these explosions. To achieve this goal, we need an accurate geophysical model of the SPE site. A Large-N seismic array that was deployed at the SPE site during one of the chemical explosions (SPE-5) helps us construct high-resolution local geophysical model. The Large-N seismic array consists of 996 geophones, and covers an area of approximately 2 × 2.5 km. The array is located in the northern end of the Yucca Flat basin, at a transition from Climax Stock (granite) to Yucca Flat (alluvium). In addition to the SPE-5 explosion, the Large-N array also recorded 53 weight drops. Using the Large-N seismic array recordings, we perform body wave and surface wave velocity analysis, and obtain 3D seismic imaging of the SPE site for the top crust of approximately 1 km. The imaging results show clear variation of geophysical parameter with local geological structures, including heterogeneous weathering layer and various rock types. The results of this work are being incorporated in the larger 3D modeling effort of the SPE program to validate the predictive models developed for the site.

Proof Rules for Automated Compositional Verification through Learning

NASA Technical Reports Server (NTRS)

Barringer, Howard; Giannakopoulou, Dimitra; Pasareanu, Corina S.

2003-01-01

Compositional proof systems not only enable the stepwise development of concurrent processes but also provide a basis to alleviate the state explosion problem associated with model checking. An assume-guarantee style of specification and reasoning has long been advocated to achieve compositionality. However, this style of reasoning is often non-trivial, typically requiring human input to determine appropriate assumptions. In this paper, we present novel assume- guarantee rules in the setting of finite labelled transition systems with blocking communication. We show how these rules can be applied in an iterative and fully automated fashion within a framework based on learning.

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.

Molecular Outflows: Explosive versus Protostellar

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

Zapata, Luis A.; Rodríguez, Luis F.; Palau, Aina

2017-02-10

With the recent recognition of a second, distinctive class of molecular outflows, namely the explosive ones not directly connected to the accretion–ejection process in star formation, a juxtaposition of the morphological and kinematic properties of both classes is warranted. By applying the same method used in Zapata et al., and using {sup 12}CO( J = 2-1) archival data from the Submillimeter Array, we contrast two well-known explosive objects, Orion KL and DR21, to HH 211 and DG Tau B, two flows representative of classical low-mass protostellar outflows. At the moment, there are only two well-established cases of explosive outflows, butmore » with the full availability of ALMA we expect that more examples will be found in the near future. The main results are the largely different spatial distributions of the explosive flows, consisting of numerous narrow straight filament-like ejections with different orientations and in almost an isotropic configuration, the redshifted with respect to the blueshifted components of the flows (maximally separated in protostellar, largely overlapping in explosive outflows), the very-well-defined Hubble flow-like increase of velocity with distance from the origin in the explosive filaments versus the mostly non-organized CO velocity field in protostellar objects, and huge inequalities in mass, momentum, and energy of the two classes, at least for the case of low-mass flows. Finally, all the molecular filaments in the explosive outflows point back to approximately a central position (i.e., the place where its “exciting source” was located), contrary to the bulk of the molecular material within the protostellar outflows.« less

Micro-explosion of compound drops

NASA Astrophysics Data System (ADS)

Chen, Chun-Kuei; Lin, Ta-Hui

2014-08-01

Introducing water into spray combustion systems, by either water-in-oil emulsification or supplementary water injection, is one of the major techniques for combustion improvement and NOx reduction. Plentiful researches are available on combustion of water-in-oil emulsion fuel drops. The emulsified liquid is a heterogeneous mixture of immiscible liquids. One component forms the continuous phase and the other component forms the discrete phase. The discrete phase consists of globules of the one fluid that are suspended in the continuous phase fluid. Water-in-oil emulsions are commonly considered for combustion applications because emulsions can result in micro-explosion, thereby reducing the average drop diameter to enhance liquid vaporization, and suppressing the formation of soot and NOx. However, the water addition generally does not exceed about 20% for smooth engine operations[!, 21. The combustion characteristics and micro-explosion of emulsion drop were studied by many researchers. The micro-explosion of water in fuel emulsion drops was caused by very fast growth of superheated water vapor bubbles, its superheat limits must be lower than the boiling point temperature of the fuel. These bubbles were primarily governed by the pressure difference between the superheated vapor and the liquid, and by the inertia imparted to the liquid by the motion of the bubble surface[3 6 In this study, we used a coaxial nozzle to generation the multi-component drop. The different type of water-in-oil fuel drops called the compound drops. Unlike an emulsion drop, a compound drop consists of a water core and a fuel shell, which can originate from the phase separation of emulsion[7, 81 or a water drop colliding with a fuel drop[9, 101 Burning and micro-explosion of compound drops have been found to be distinct from those of emulsion drops[9-111 Wang et al.[9 , 101 studied the combustion characteristics of collision merged alkane-water drops. The merged drops appeared in adhesive and inserted manners. The drop ignition delay time increased with increasing water content. The average burning rate of alkane-water drops decreased with increasing water content. In the burning process, hexadecane-water drops exhibited flash vaporization or flame extinction. Heterogeneous explosion was occasionally observed in drops with trapped air bubbles. The air bubbles were assumed to be the nucleation points of the heterogeneous explosions. Chen and Lin[11 studied the characteristics of water-in-dodecane compound drop with different water content, diameter of drop and environmental oxygen concentration. The vaporization rate increased with increasing environmental oxygen concentration. The compound drops micro-exploded during the burning process in a random way. The number of micro-explosions was majorly influenced by drop diameter, followed by environmental oxygen concentration. Water content had a weaker effect on micro-explosion. As available literature and research results of compound drop burning are scarce, their combustion and micro-explosion behaviors are still poorly understood. In this regard, we changed the drop nature as compound drops to study their combustion characteristics and micro-explosion phenomena.

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

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

McClelland, M A; Maienschein, J L; Howard, W M

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

Very Deep inside the SN 1987A Core Ejecta: Molecular Structures Seen in 3D

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

Abellán, F. J.; Marcaide, J. M.; Indebetouw, R.

2017-06-20

Most massive stars end their lives in core-collapse supernova explosions and enrich the interstellar medium with explosively nucleosynthesized elements. Following core collapse, the explosion is subject to instabilities as the shock propagates outward through the progenitor star. Observations of the composition and structure of the innermost regions of a core-collapse supernova provide a direct probe of the instabilities and nucleosynthetic products. SN 1987A in the Large Magellanic Cloud is one of very few supernovae for which the inner ejecta can be spatially resolved but are not yet strongly affected by interaction with the surroundings. Our observations of SN 1987A withmore » the Atacama Large Millimeter/submillimeter Array are of the highest resolution to date and reveal the detailed morphology of cold molecular gas in the innermost regions of the remnant. The 3D distributions of carbon and silicon monoxide (CO and SiO) emission differ, but both have a central deficit, or torus-like distribution, possibly a result of radioactive heating during the first weeks (“nickel heating”). The size scales of the clumpy distribution are compared quantitatively to models, demonstrating how progenitor and explosion physics can be constrained.« less

A thermalized ion explosion model for high energy sputtering and track registration

NASA Technical Reports Server (NTRS)

Seiberling, L. E.; Griffith, J. E.; Tombrello, T. A.

1980-01-01

A velocity spectrum of neutral sputtered particles as well as a low resolution mass spectrum of sputtered molecular ions was measured for 4.74 MeV F-19(+2) incident of UF4. The velocity spectrum is dramatically different from spectra taken with low energy (keV) bombarding ions, and is shown to be consistent with a hot plasma of atoms in thermal equilibrium inside the target. A thermalized ion explosion model is proposed for high energy sputtering which is expected to describe track formation in dielectric materials. The model is shown to be consistent with the observed total sputtering yield and the dependence of the yield on the primary ionization rate of the incident ion.

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.

Preparation of 1,1'-dinitro-3,3'-azo-1,2,4-triazole

DOEpatents

Lee, Kien-Yin

1986-01-01

A new high density composition of matter, 1,1'-dinitro-3,3'-azo-1,2,4-triazole, has been synthesized using inexpensive, commonly available compounds. This compound has been found to be an explosive, and its use as a propellant is anticipated.

Polymer formulations for gettering hydrogen

DOEpatents

Shepodd, T.J.; Whinnery, L.L.

1998-11-17

A novel composition is described comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen. 1 fig.

Phreatic explosions during basaltic fissure eruptions: Kings Bowl lava field, Snake River Plain, USA

NASA Astrophysics Data System (ADS)

Hughes, Scott S.; Kobs Nawotniak, Shannon E.; Sears, Derek W. G.; Borg, Christian; Garry, William Brent; Christiansen, Eric H.; Haberle, Christopher W.; Lim, Darlene S. S.; Heldmann, Jennifer L.

2018-02-01

Physical and compositional measurements are made at the 7 km-long ( 2200 years B.P.) Kings Bowl basaltic fissure system and surrounding lava field in order to further understand the interaction of fissure-fed lavas with phreatic explosive events. These assessments are intended to elucidate the cause and potential for hazards associated with phreatic phases that occur during basaltic fissure eruptions. In the present paper we focus on a general understanding of the geological history of the site. We utilize geospatial analysis of lava surfaces, lithologic and geochemical signatures of lava flows and explosively ejected blocks, and surveys via ground observation and remote sensing. Lithologic and geochemical signatures readily distinguish between Kings Bowl and underlying pre-Kings Bowl lava flows, both of which comprise phreatic ejecta from the Kings Bowl fissure. These basalt types, as well as neighboring lava flows from the contemporaneous Wapi lava field and the older Inferno Chasm vent and outflow channel, fall compositionally within the framework of eastern Snake River Plain olivine tholeiites. Total volume of lava in the Kings Bowl field is estimated to be 0.0125 km3, compared to a previous estimate of 0.005 km3. The main (central) lava lake lost a total of 0.0018 km3 of magma by either drain-back into the fissure system or breakout flows from breached levees. Phreatic explosions along the Kings Bowl fissure system occurred after magma supply was cut off, leading to fissure evacuation, and were triggered by magma withdrawal. The fissure system produced multiple phreatic explosions and the main pit is accompanied by others that occur as subordinate pits and linear blast corridors along the fissure. The drop in magma supply and the concomitant influx of groundwater were necessary processes that led to the formation of Kings Bowl and other pits along the fissure. A conceptual model is presented that has relevance to the broader range of low-volume, monogenetic basaltic fissure eruptions on Earth, the Moon and other planetary bodies.

Response of two-phase droplets to intense electromagnetic radiation

NASA Technical Reports Server (NTRS)

Spann, James F.; Maloney, Daniel J.; Lawson, William F.; Casleton, Kent H.

1993-01-01

The response of two-phase droplets to intense radiant heating is studied to determine the incident power that is required for causing explosive boiling in the liquid phase. The droplets studied consist of strongly absorbing coal particles dispersed in a weakly absorbing water medium. Experiments are performed by confining droplets (radii of 37, 55, and 80 microns) electrodynamically and irradiating them from two sides with pulsed laser beams. Emphasis is placed on the transition region from accelerated droplet vaporization to droplet superheating and explosive boiling. The time scale observed for explosive boiling is more than 2 orders of magnitude longer than published values for pure liquids. The delayed response is the result of energy transfer limitations between the absorbing solid phase and the surrounding liquid.

Synthesis and Characterization of a New Co-Crystal Explosive with High Energy and Good Sensitivity

NASA Astrophysics Data System (ADS)

Gao, Han; Jiang, Wei; Liu, Jie; Hao, Gazi; Xiao, Lei; Ke, Xiang; Chen, Teng

2017-10-01

A new energetic co-crystal consisting of one of the most powerful explosive molecules 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the military explosive cyclotrimethylenetrinitramine (RDX) was prepared with a simple solvent evaporation method. Scanning electron microscopy (SEM) revealed the morphology of the bar-shaped product, which differed greatly from the morphology of the individual components. Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction spectrum (XRD), and differential scanning calorimetry (DSC) proved the formation of the co-crystal at the molecular level. The result of mechanical sensitivity test indicated the sensitivity was effectively reduced compared to raw CL-20. Finally, a possible crystallization mechanism was discussed.

Preliminary volcano-hazard assessment for Aniakchak Volcano, Alaska

USGS Publications Warehouse

Neal, Christina A.; McGimsey, Robert G.; Miller, Thomas P.; Riehle, James R.; Waythomas, Christopher F.

2000-01-01

Aniakchak is an active volcano located on the Alaska Peninsula 670 kilometers southwest of Anchorage. The volcano consists of a dramatic, 10-kilometer-diameter, 0.5 to 1.0-kilometer-deep caldera that formed during a catastrophic eruption 3,500 years ago. Since then, at least a dozen separate vents within the caldera have erupted, often explosively, to produce lava flows and widespread tephra (ash) deposits. The most recent eruption at Aniakchak occurred in 1931 and was one of the largest explosive eruptions in Alaska in the last 100 years. Although Aniakchak volcano presently shows no signs of unrest, explosive and nonexplosive eruptions will occur in the future. Awareness of the hazards posed by future eruptions is a key factor in minimizing impact.

Soviet test yields

NASA Astrophysics Data System (ADS)

Vergino, Eileen S.

Soviet seismologists have published descriptions of 96 nuclear explosions conducted from 1961 through 1972 at the Semipalatinsk test site, in Kazakhstan, central Asia [Bocharov et al., 1989]. With the exception of releasing news about some of their peaceful nuclear explosions (PNEs) the Soviets have never before published such a body of information.To estimate the seismic yield of a nuclear explosion it is necessary to obtain a calibrated magnitude-yield relationship based on events with known yields and with a consistent set of seismic magnitudes. U.S. estimation of Soviet test yields has been done through application of relationships to the Soviet sites based on the U.S. experience at the Nevada Test Site (NTS), making some correction for differences due to attenuation and near-source coupling of seismic waves.

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

Mattes, R.H.; Bacho, A.; Wade, L.V.

The Lake Lynn Laboratory is a multipurpose mining research laboratory operated by the Bureau of Mines and located in Fairchance, Pa. It consists of both surface and underground facilities. The initial focus of the facility, scheduled for full operation in fall 1982, will be on the problems of fires and explosions in mines. The initial experimental explosion was fired on March 3, 1982. The intent of this document is to provide the reader with detailed information on the physical capabilities of the Lake Lynn Laboratory. Subsequent publications will focus on the capabilities of Lake Lynn as compared with those ofmore » other similar facilities worldwide, and a comparison of initial explosion test results realized at Lake Lynn and comparable results from the Bruceton Experimental Mines.« less

NanoSIMS results from olivine-hosted melt embayments: Modeling ascent rate in explosive basaltic eruptions

NASA Astrophysics Data System (ADS)

Lloyd, A. S.; Plank, T.; Ruprecht, P.; Hauri, E. H.; Gonnermann, H. M.; Rose, W. I.

2012-12-01

A critical parameter governing the explosivity of volcanic eruptions is the rate at which magma ascends and degases, because this affects bubble nucleation, coalescence, and ultimately fragmentation. Although several methods have been used to determine magma ascent rates, it remains a poorly constrained parameter for most eruptions. One promising method employs diffusion modeling of H2O and CO2 concentration gradients in melt embayments/open melt inclusions [1,2]. Here we utilize the fine spatial resolution of the nanoSIMS to obtain concentration gradients for five volatile species, improving upon previous efforts that were more limited in spatial resolution (FTIR, [1]) and in number of volatile analytes (H2O only by BSE, [2]). Focusing on explosive basaltic eruptions, for which very little is known about ascent rates, we chose ash and lapilli samples from the Oct 1974 sub-plinian eruption of Volcán de Fuego. Glassy, olivine-hosted embayments with evidence of outlet bubbles were analyzed by nanoSIMS at a minimum distance between spots of 15 μm. Major element zonation in the embayments was investigated by EMP, and high resolution BSE images were captured to complement the nanoSIMS spot measurements for H2O (as in [2]). We report analyses for 5 embayments that vary in length from 100 to 350 μm. Low-solubility volatiles (CO2, H2O, S) decrease towards the embayment outlet, consistent with diffusive reequilibration with the more-degassed surrounding melt. High-solubility volatiles (Cl, F) increase towards the outlet, apparently behaving as magmaphile elements. Major elements exhibit constant concentrations along the embayment, except for a 20-50 μm wide zone near the embayment outlet, perhaps representing a boundary layer at the outlet bubble, where concentrations vary consistent with olivine and clinopyroxene microlite growth. BSE grayscale values are thus affected by both H2O diffusion and major element zonation at the embayment outlet, and cannot be used to estimate H2O concentration gradients [2]. Forward modeling of CO2 and H2O profiles takes into account temperature- and composition-dependent diffusivities and a closed-system degassing path for the exterior magma (as observed in melt inclusions from the same sample). Assuming a constant decompression rate from 200 MPa and an initial composition of 600 ppm CO2 and 4.3 wt% H2O at 1030°C, models yield preliminary results with very rapid ascent times (100 s, or 2 MPa/s). A two-stage model, however, allows slower decompression during CO2 exsolution (0.1 MPa/s) and faster ascent when H2O begins to exsolve (1.5 MPa/s), for total ascent times on the order of 10 to 20 minutes. This example highlights the additional constraints that come from measuring multiple diffusing species. [1] Liu et al, JGR, 2007 [2] Humphreys et al, EPSL, 2008.

Merging Infrasound and Electromagnetic Signals as a Means for Nuclear Explosion Detection

NASA Astrophysics Data System (ADS)

Ashkenazy, Joseph; Lipshtat, Azi; Kesar, Amit S.; Pistinner, Shlomo; Ben Horin, Yochai

2016-04-01

The infrasound monitoring network of the CTBT consists of 60 stations. These stations are capable of detecting atmospheric events, and may provide approximate location within time scale of a few hours. However, the nature of these events cannot be deduced from the infrasound signal. More than two decades ago it was proposed to use the electromagnetic pulse (EMP) as a means of discriminating nuclear explosion from other atmospheric events. An EMP is a unique signature of nuclear explosion and is not detected from chemical ones. Nevertheless, it was decided to exclude the EMP technology from the official CTBT verification regime, mainly because of the risk of high false alarm rate, due to lightning electromagnetic pulses [1]. Here we present a method of integrating the information retrieved from the infrasound system with the EMP signal which enables us to discriminate between lightning discharges and nuclear explosions. Furthermore, we show how spectral and other characteristics of the electromagnetic signal emitted from a nuclear explosion are distinguished from those of lightning discharge. We estimate the false alarm probability of detecting a lightning discharge from a given area of the infrasound event, and identifying it as a signature of a nuclear explosion. We show that this probability is very low and conclude that the combination of infrasound monitoring and EMP spectral analysis may produce a reliable method for identifying nuclear explosions. [1] R. Johnson, Unfinished Business: The Negotiation of the CTBT and the End of Nuclear Testing, United Nations Institute for Disarmament Research, 2009.

Ground Truth Collections for Explosions in Northern Fennoscandia and Russia

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

Harris, D B; Ringdal, F; Kremenetskaya, E

2003-07-28

This project is providing ground-truth information on explosions conducted at the principal mines within 500 kilometers of the ARCES station, and is assembling a seismic waveform database for these events from local and regional stations. The principal mines of interest are in northwest Russia (Khibiny Massif, Olenogorsk, Zapolyamy, and Kovdor groups) and Sweden (Malmberget, Kiruna). These mines form a natural laboratory for examining the variation of mining explosion observations with source type, since they include colocated surface and underground mines and mines conducting a variety of different shot types. In September 2002 we deployed two lines of temporary stations frommore » the Khibiny Massif through and to the north of the ARCES station. This deployment is producing data that will allow researchers to examine the variation of discriminants caused by varying source-receiver distance and the diversity of explosion types. To date, we have collected ground-truth information on 1,118 explosions in the Kola Peninsula, and have assembled waveform data for approximately 700 of these. The database includes waveforms from instruments temporarily deployed in the Khibiny Massif mines, from the Apatity network just outside of the Massif, from LVZ, KEV and ARCES, and from the stations deployed along the two lines into northern Norway. In this paper we present representative waveforms for several types of shots recorded at various regional distances. We have conducted a preliminary study of the variation of phase ratios as a function of source type. This study shows significant differences in Pd/Sn and Pd/Lg ratios for two types of mining explosions: surface ripple-fired explosions and compact underground explosions. Compact explosions are, typically, underground explosions of a few tons with only one or two short delays, and are the closest approximation to single, well-tamped explosions available in the Khibiny mines. The surface shots typically are much larger (ranging up to hundreds of tons), with many delays. The surface mine that we present results for typically also conducts several distinct shots across the mine nearly simultaneously (with a few seconds or tens of seconds). Measured phase ratios are more consistent for compact underground explosions. This consistency is an expected result given the smaller scope for shot variation in these smaller events. In addition, Pd/Lg ratios appear more stable than Pd/Sn ratios for both types of events. The most interesting result is that the compact underground explosions are richer in shear energy (i.e. having smaller P/S ratios) than their surface ripple-fired counterparts. We continue to work on an approach for identifying the principal mines to be targeted for screening at a particular station. Often, routine industrial blasts constitute a large proportion of events detected by monitoring stations close to major mining districts. Many mines may be present, and it may be a problem to determine which subset of mines is responsible for the majority of the events, and should be prime candidates for the deployment of ground-truth collection resources. Our solution to this problem entails several steps. The first is to find geographic clusters of events that may correspond to major groups of mines. For this step, we use event density maps generated from existing network catalogs. This year we examined some of the tradeoffs in generating event density maps: use of automated bulletins to produce maps vs. analyst-reviewed bulletins, and the amount of time required to produce stables maps which can be used to identify significant mines.« less

Time-resolved explosion of intense-laser-heated clusters.

PubMed

Kim, K Y; Alexeev, I; Parra, E; Milchberg, H M

2003-01-17

We investigate the femtosecond explosive dynamics of intense laser-heated argon clusters by measuring the cluster complex transient polarizability. The time evolution of the polarizability is characteristic of competition in the optical response between supercritical and subcritical density regions of the expanding cluster. The results are consistent with time-resolved Rayleigh scattering measurements, and bear out the predictions of a recent laser-cluster interaction model [H. M. Milchberg, S. J. McNaught, and E. Parra, Phys. Rev. E 64, 056402 (2001)

Exploratory Development on an Electronic Safing and Arming Device for Ordnance Fuzing

DTIC Science & Technology

1983-02-01

to the bridges. Two units were subjected to MIL-STD-331, Test 101, Jolt. The EBMs were placed in the S & A cavity of an M739 fuze body for this test...of the program was to explore a concept for a safe, reliable, general purpose, low cost, electronic, A ’ zsafing and arming ( S & A ) system for use in...breadboard model hardware of the electronic S & A device. The electronic S & A devicu consists of an explosive barrier moduls (EBM) explosive train

Estimation of Metal Acceleration by an SF5 Containing Explosive

DTIC Science & Technology

1991-06-30

cylinder wall acceleration, the wall energies for the baseline composition and for the composition CW2 were calculated by three different methods : KSM, 6...computaticno! method to calculate the cylinder energies needed for comparison with expermental data, it was decided to compare data from three known methods ...detonation pressure given for the GAB method in Reference 8. They are E(6mm) = 0.1272 (Isp X density)1 .5 - 0.021, and E(l9mm) = 0.1580 (Isp x density) 1 .5

Acute Inhalation Toxicity Effects of Explosively Disseminated - - XM82 Grenade - - Titanium Dioxide

DTIC Science & Technology

1992-06-01

Transfer lead ( PBXN -5) * Booster lead (Composition CH-6) * Burster (Composition A-S) (dispersed the TiO2 ) * TiO2 Detailed descriptions of XM82 grenade...Control 4.15 52.93 79.3 317 0.62 23.90 12.8 66 Fuse/Fuel 4.55 55.62 74.3 262 0.68 29.81 6.1 63 Low Cone 4.82 S0.68 64.9 342 0.52 23.45 9.8 106 Mid Cone

Survey of Hydrogen Combustion Properties

NASA Technical Reports Server (NTRS)

Drell, Isadore L; Belles, Frank E

1958-01-01

This literature digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.

Rays as weapons.

PubMed

Vogel, H

2007-08-01

Ionizing radiation is being regarded as life threatening. Therefore, accidents in nuclear power plants are considered equal threatening as nuclear bomb explosions, and attacks with dirty bombs are thought as dangerous as nuclear weapon explosions. However, there are differences between a nuclear bomb explosion, the largest imaginable accident in a nuclear power plant, and an attack with a dirty bomb. It is intended to point them out. The processes are described, which damage in a nuclear bomb explosion, in the largest imaginable accident in a nuclear power plant, and in an attack with a dirty bomb. Their effects are compared with each other, i.e. explosion, heat, shock wave (blast), ionizing radiation, and fallout. In the center of the explosion of a nuclear bomb, the temperature rises to 100Mio degrees C, this induces damaging heat radiation and shock wave. In the largest imaginable accident in a nuclear power plant and in the conventional explosion of a dirty bomb, the temperature may rise up to 3000 degrees C, heat radiation and blast are limited to a short distance. In nuclear power plants, explosions due to oxyhydrogen gas or steam may occur. In nuclear explosions the dispersed radioactive material (fall out) consists mainly of isotopes with short half-life, in nuclear power plants and in dirty bomb attacks with longer half-life. The amount of fall out is comparable in nuclear bomb explosions with that in the largest imaginable accident in a nuclear power plant, it is smaller in attacks with dirty bombs. An explosion in a nuclear power plant even in the largest imaginable accident is not a nuclear explosion. In Hiroshima and Nagasaki, there were 200,000 victims nearly all by heat and blast, some 300 died by ionizing radiation. In Chernobyl, there have been less than 100 victims due to ionizing radiation up till now. A dirty bomb kills possibly with the explosion of conventional explosive, the dispersed radioactive material may damage individuals. The incorporation of irradiating substances may kill and be difficult to detect (Litvinenko). A new form of (government supported) terrorism/crime appears possible. The differences are important between a nuclear weapon explosion, the largest imaginable accident in a nuclear power plant, and an attack with a dirty bomb. Nuclear weapons kill by heat and blast; in the largest imaginable accident in a nuclear power plant, they are less strong and limited to the plant; an attack with a dirty bomb is as life threatening as an ("ordinary") bomb attack, dispersed radiating material may be a risk for individuals.

Nucleosynthesis in Core-Collapse Supernovae

NASA Astrophysics Data System (ADS)

Stevenson, Taylor Shannon; Viktoria Ohstrom, Eva; Harris, James Austin; Hix, William R.

2018-01-01

The nucleosynthesis which occurs in core-collapse supernovae (CCSN) is one of the most important sources of elements in the universe. Elements from Oxygen through Iron come predominantly from supernovae, and contributions of heavier elements are also possible through processes like the weak r-process, the gamma process and the light element primary process. The composition of the ejecta depends on the mechanism of the explosion, thus simulations of high physical fidelity are needed to explore what elements and isotopes CCSN can contribute to Galactic Chemical Evolution. We will analyze the nucleosynthesis results from self-consistent CCSN simulations performed with CHIMERA, a multi-dimensional neutrino radiation-hydrodynamics code. Much of our understanding of CCSN nucleosynthesis comes from parameterized models, but unlike CHIMERA these fail to address essential physics, including turbulent flow/instability and neutrino-matter interaction. We will present nucleosynthesis predictions for the explosion of a 9.6 solar mass first generation star, relying both on results of the 160 species nuclear reaction network used in CHIMERA within this model and on post-processing with a more extensive network. The lowest mass iron core-collapse supernovae, like this model, are distinct from their more massive brethren, with their explosion mechanism and nucleosynthesis being more like electron capture supernovae resulting from Oxygen-Neon white dwarves. We will highlight the differences between the nucleosynthesis in this model and more massive supernovae. The inline 160 species network is a feature unique to CHIMERA, making this the most sophisticated model to date for a star of this type. We will discuss the need and mechanism to extrapolate the post-processing to times post-simulation and analyze the uncertainties this introduces for supernova nucleosynthesis. We will also compare the results from the inline 160 species network to the post-processing results to study further uncertainties introduced by post-processing. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, and the National Science Foundation Nuclear Theory Program (PHY-1516197).

Characteristics of acoustic wave from atmospheric nuclear explosions conducted at the USSR Test Sites

NASA Astrophysics Data System (ADS)

Sokolova, Inna

2015-04-01

Availability of the acoustic wave on the record of microbarograph is one of discriminate signs of atmospheric (surface layer of atmosphere) and contact explosions. Nowadays there is large number of air wave records from chemical explosions recorded by the IMS infrasound stations installed during recent decade. But there is small number of air wave records from nuclear explosions as air and contact nuclear explosions had been conducted since 1945 to 1962, before the Limited Test Ban Treaty was signed in 1963 (the treaty banning nuclear weapon tests in the atmosphere, in outer space and under water) by the Great Britain, USSR and USA. That time there was small number of installed microbarographs. First infrasound stations in the USSR appeared in 1954, and by the moment of the USSR collapse the network consisted of 25 infrasound stations, 3 of which were located on Kazakhstan territory - in Kurchatov (East Kazakhstan), in Borovoye Observatory (North Kazakhstan) and Talgar Observatory (Northern Tien Shan). The microbarograph of Talgar Observatory was installed in 1962 and recorded large number of air nuclear explosions conducted at Semipalatinsk Test Site and Novaya Zemlya Test Site. The epicentral distance to the STS was ~700 km, and to Novaya Zemlya Test Site ~3500 km. The historical analog records of the microbarograph were analyzed on the availability of the acoustic wave. The selected records were digitized, the database of acoustic signals from nuclear explosions was created. In addition, acoustic signals from atmospheric nuclear explosions conducted at the USSR Test Sites were recorded by analogue broadband seismic stations at wide range of epicentral distances, 300-3600 km. These signals coincide well by its form and spectral content with records of microbarographs and can be used for monitoring tasks and discrimination in places where infrasound observations are absent. Nuclear explosions which records contained acoustic wave were from 0.03 to 30 kt yield for the STS, and from 8.3 to 25 Mt yield for Novaya Zemlya Test Site region. The peculiarities of the wave pattern and spectral content of the acoustic wave records, and relation regularities of acoustic wave amplitude and periods with explosion yield and distance were investigated. The created database can be applied in different monitoring tasks, such as infrasound stations calibration, discrimination of nuclear explosions, precision of nuclear explosions parameters, determination of the explosion yield etc.

On-line image analysis of the stromboli volcanic activity recorded by the surveillance camera helps the forecasting of the major eruptive events.

NASA Astrophysics Data System (ADS)

Cristaldi, A.; Coltelli, M.; Mangiagli, S.; Pecora, E.

2003-04-01

The typical activity of Stromboli consists of intermittent mild explosions lasting a few seconds, which take place at different vents and at variable intervals, the most common time interval being 10-20 minutes. However, the routine activity can be interrupted by more violent, paroxysmal explosions, that eject m-sized scoriaceous bombs and lava blocks to a distance of several hundreds of meters from the craters, endangering the numerous tourists that watch the spectacular activity from the volcano's summit located about two hundreds meters from the active vents. On average, 1-2 paroxysmal explosions occurred per year over the past century, but this statistic may be underestimated in absence of continuous monitoring. For this reason from summer 1996 a remote surveillance camera works on Stromboli recording continuously the volcanic activity. It is located on Pizzo Sopra la Fossa, 100 metres above the crater terrace where are the active vents. Using image analysis we seeks to identify any change of the explosive activity trend that could precede a particular eruptive event, like paroxysmal explosions, fire fountains, lava flows. From the day of the camera installation up to present 12 paroxysmal events and lava flows occurred. The analysis include the counting of the explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetics energy. The plot of dissipated energy by each crater versus time shows a cyclic behavior with max and min of explosive activity ranging from a few days to a month. Often the craters show opposite trends so when the activity decreases in a crater, increases in the other. Before every paroxysmal explosions recorded, the crater that produced the event decreased and then stopped its activity from a few days to weeks before. The other crater tried to compensate increasing its activity and when it declined the paroxysmal explosion occurred suddenly at the former site. From September 2001 an on-line image analyzer called VAMOS (Volcanic Activity MOnitoring System) operates detection and classification of explosive events in quasi real-time. The system has automatically recorded and analyzed the change in the energetic trend that preceded the 20 October 2001 paroxysmal explosion that killed a woman and the strong explosive activity that preceded the onset of 28 December 2002 lava flow eruption.

The microbial composition and metabolic potential of the ovine rumen

USDA-ARS?s Scientific Manuscript database

The rumen is efficient at biotransforming nitroaromatic explosive compounds, such as TNT, RDX, and HMX, which have been used widely in US military munitions. These compounds are present in > 4,000 military items, from large bombs to very small igniters. However, their manufacturing processes have g...

Enhancing the microbial population within poultry

USDA-ARS?s Scientific Manuscript database

Recent research advances have led to an explosion in information on the composition and impact of the microbiome on health and productivity that is nothing short of revolutionary. The accelerating rate of discoveries is dizzying, and we see in a way that we never could before the importance of the ...

Reverberant Microwave Propagation

DTIC Science & Technology

2008-10-01

HERO Hazards of Electromagnetic Radiation to Ordnance HP Hewlett Packard HWD Half-Wave Dipole IEC International Electrotechnical Commission IEE...composite panels used in new ship design; Hazards of Electromagnetic Radiation to Ordnance ( HERO ) analyses; and digital wireless system performance...Electro-Explosive Device EMC Electromagnetic Compatibility ft Foot (feet) GHz Gigahertz HERO Hazards of Electromagnetic

Duke Ellington: The Man and His Music.

ERIC Educational Resources Information Center

George, Luvenia A.

1999-01-01

Provides a chronology of Edward Kennedy "Duke" Ellington's career divided into four periods (Sound and Style, Creative Explosion, Beyond Jazz, and The Last Decade). Offers a synopsis of his musical development, listing compositions written during each phase. Includes a list of resources and a sample lesson for "Koko" by Duke Ellington. (CMK)

Phase field model of the nanoscale evolution during the explosive crystallization phenomenon

NASA Astrophysics Data System (ADS)

Lombardo, S. F.; Boninelli, S.; Cristiano, F.; Deretzis, I.; Grimaldi, M. G.; Huet, K.; Napolitani, E.; La Magna, A.

2018-03-01

Explosive crystallization is a well known phenomenon occurring due to the thermodynamic instability of strongly under-cooled liquids, which is particularly relevant in pulsed laser annealing processes of amorphous semiconductor materials due to the globally exothermic amorphous-to-liquid-to-crystal transition pathway. In spite of the assessed understanding of this phenomenon, quantitative predictions of the material kinetics promoted by explosive crystallization are hardly achieved due to the lack of a consistent model able to simulate the concurrent kinetics of the amorphous-liquid and liquid-crystal interfaces. Here, we propose a multi-well phase-field model specifically suited for the simulation of explosive crystallization induced by pulsed laser irradiation in the nanosecond time scale. The numerical implementation of the model is robust despite the discontinuous jumps of the interface speed induced by the phenomenon. The predictive potential of the simulations is demonstrated by means of comparisons of the modelling predictions with experimental data in terms of in situ reflectivity measurements and ex-situ micro-structural and chemical characterization.

An outburst from a massive star 40 days before a supernova explosion.

PubMed

Ofek, E O; Sullivan, M; Cenko, S B; Kasliwal, M M; Gal-Yam, A; Kulkarni, S R; Arcavi, I; Bildsten, L; Bloom, J S; Horesh, A; Howell, D A; Filippenko, A V; Laher, R; Murray, D; Nakar, E; Nugent, P E; Silverman, J M; Shaviv, N J; Surace, J; Yaron, O

2013-02-07

Some observations suggest that very massive stars experience extreme mass-loss episodes shortly before they explode as supernovae, as do several models. Establishing a causal connection between these mass-loss episodes and the final explosion would provide a novel way to study pre-supernova massive-star evolution. Here we report observations of a mass-loss event detected 40 days before the explosion of the type IIn supernova SN 2010mc (also known as PTF 10tel). Our photometric and spectroscopic data suggest that this event is a result of an energetic outburst, radiating at least 6 × 10(47) erg of energy and releasing about 10(-2) solar masses of material at typical velocities of 2,000 km s(-1). The temporal proximity of the mass-loss outburst and the supernova explosion implies a causal connection between them. Moreover, we find that the outburst luminosity and velocity are consistent with the predictions of the wave-driven pulsation model, and disfavour alternative suggestions.

Development of a flyer design to perform plate impact shock-release-shock experiments on explosives

NASA Astrophysics Data System (ADS)

Finnegan, Simon; Ferguson, James; Millett, Jeremy; Goff, Michael

2017-06-01

A flyer design to generate a shock-release-shock loading history within a gas gun target was developed before being used to study the response of an HMX based explosive. The flyer consisted of two flyer plates separated by a vacuum gap. This created a rear free surface that, with correct material choice, allowed the target to release to close to ambient pressure between the initial shock and subsequent re-shock. The design was validated by impacting piezoelectric pin arrays to record the front flyer deformation. Shots were performed on PCTFE targets to record the shock states generated in an inert material prior to subjecting an HMX based explosive to the same loading. The response of the explosive to this loading history was recorded using magnetic particle velocity (PV) gauges embedded within the targets. The behavior during the run to detonation is compared with the response to sustained shocks at similar input pressures.

Increasing the selectivity and sensitivity of gas sensors for the detection of explosives

NASA Astrophysics Data System (ADS)

Mallin, Daniel

Over the past decade, the use of improvised explosive devices (IEDs) has increased, domestically and internationally, highlighting a growing need for a method to quickly and reliably detect explosive devices in both military and civilian environments before the explosive can cause damage. Conventional techniques have been successful in explosive detection, however they typically suffer from enormous costs in capital equipment and maintenance, costs in energy consumption, sampling, operational related expenses, and lack of continuous and real-time monitoring. The goal was thus to produce an inexpensive, portable sensor that continuously monitors the environment, quickly detects the presence of explosive compounds and alerts the user. In 2012, here at URI, a sensor design was proposed for the detection of triacetone triperoxide (TATP). The design entailed a thermodynamic gas sensor that measures the heat of decomposition between trace TATP vapor and a metal oxide catalyst film. The sensor was able to detect TATP vapor at the part per million level (ppm) and showed great promise for eventual commercial use, however, the sensor lacked selectivity. Thus, the specific objective of this work was to take the original sensor design proposed in 2012 and to make several key improvements to advance the sensor towards commercialization. It was demonstrated that a sensor can be engineered to detect TATP and ignore the effects of interferent H2O2 molecules by doping SnO2 films with varying amounts of Pd. Compared with a pure SnO2 catalyst, a SnO2, film doped with 8 wt. % Pd had the highest selectivity between TATP and H2O2. Also, at 12 wt. % Pd, the response to TATP and H2O2 was enhanced, indicating that sensitivity, not only selectivity, can be increased by modifying the composition of the catalyst. An orthogonal detection system was demonstrated. The platform consists of two independent sensing mechanisms, one thermodynamic and one conductometric, which take measurements from the same catalyst simultaneously and provide a redundancy in response for positive explosive identification. TATP, 2,6-DNT and ammonium nitrate were reliably detected. Each analyte displayed a unique conductometric signature and the results indicated a detection limit at the ppb level. A preconcentrator was designed to enhance the sensitivity of the sensor and was successfully demonstrated. The magnitude of the sensor response increased from by 50% and the preconcentrator could be operated semi-continuously, maintaining one of the most attractive features of this sensor platform: the capability to operate in real time. A method to filter out extraneous heat signals from sensor response using a dynamic control was also successfully demonstrated and will likely be a fixture in all sensor experimentation and design moving forward. Finally, two MEMS based sensor platforms were designed and fabricated. It was theoretically demonstrated that the newest iteration of the MEMS sensor consumes considerably less power due to thinner membranes, a smaller active surface area and an overall smaller thermal mass, allowing for the possibility of creating networks of sensor arrays, even in a portable device.

Characterizing the X-ray Emission in Small Magellanic Cloud Supernova Remnants

NASA Astrophysics Data System (ADS)

Man, Nicole; Auchettl, Katie; Lopez, Laura

2018-01-01

The Small Magellanic Cloud is a close, metal-poor galaxy with active star formation, and it has a diverse population of 24 supernova remnants (SNRs) that have been identified at several wavelengths. Past work has characterized the X-ray emission in these sources separately and aimed to constrain their explosive origins from observations with Chandra and XMM-Newton. Three SNRs have possible evidence for Type Ia explosions based on strong Fe-L emission in their X-ray spectra, although the environments and intermediate-mass element abundances are more consistent with those of core-collapse SNe. In this poster, we analyze the archival Chandra and XMM-Newton observations of the SMC SNR sample, and we model the sources' X-ray spectra in a systematic way to derive the plasma properties and to constrain the nature of the explosions. In one SNR, we note the presence of an X-ray binary near the source's geometric center, suggesting the compact object was produced in the SN explosion. As one of only three SNRs known in the Local Group to host a binary system, this source is worthy of follow-up investigations to probe explosions of massive stars in binary systems.

Gas chromatography/ion mobility spectrometry as a hyphenated technique for improved explosives detection and analysis

NASA Technical Reports Server (NTRS)

Mercado, AL; Marsden, Paul

1995-01-01

Ion Mobility Spectrometry (IMS) is currently being successfully applied to the problem of on-line trace detection of plastic and other explosives in airports and other facilities. The methods of sample retrieval primarily consist of batch sampling for particulate residue on a filter card for introduction into the IMS. The sample is desorbed into the IMS using air as the carrier and negative ions of the explosives are detected, some as an adduct with a reagent ion such as Cl(-). Based on studies and tests conducted by different airport authorities, this method seems to work well for low vapor pressure explosives such as RDX and PETN, as well as TNT that are highly adsorptive and can be found in nanogram quantities on contaminated surfaces. Recently, the changing terrorist threat and the adoption of new marking agents for plastic explosives has meant that the sample introduction and analysis capabilities of the IMS must be enhanced in order to keep up with other detector developments. The IMS has sufficient analytical resolution for a few threat compounds but the IMS Plasmogram becomes increasingly more difficult to interpret when the sample mixture gets more complex.

Type Ia Supernova Explosions from Hybrid Carbon-Oxygen-Neon White Dwarf Progenitors

NASA Astrophysics Data System (ADS)

Willcox, Donald E.; Townsley, Dean M.; Calder, Alan C.; Denissenkov, Pavel A.; Herwig, Falk

2016-11-01

Motivated by recent results in stellar evolution that predict the existence of hybrid white dwarf (WD) stars with a C-O core inside an O-Ne shell, we simulate thermonuclear (Type Ia) supernovae from these hybrid progenitors. We use the FLASH code to perform multidimensional simulations in the deflagration-to-detonation transition (DDT) explosion paradigm. Our hybrid progenitor models were produced with the MESA stellar evolution code and include the effects of the Urca process, and we map the progenitor model to the FLASH grid. We performed a suite of DDT simulations over a range of ignition conditions consistent with the progenitor’s thermal and convective structure assuming multiple ignition points. To compare the results from these hybrid WD stars to previous results from C-O WDs, we construct a set of C-O WD models with similar properties and similarly simulate a suite of explosions. We find that despite significant variability within each suite, trends distinguishing the explosions are apparent in their {}56{Ni} yields and the kinetic properties of the ejecta. We compare our results with other recent work that studies explosions from these hybrid progenitors.

MASTER OT J004207.99+405501.1/M31LRN 2015 luminous red nova in M31: discovery, light curve, hydrodynamics and evolution

NASA Astrophysics Data System (ADS)

Lipunov, V. M.; Blinnikov, S.; Gorbovskoy, E.; Tutukov, A.; Baklanov, P.; Krushinski, V.; Tiurina, N.; Balanutsa, P.; Kuznetsov, A.; Kornilov, V.; Gorbunov, I.; Shumkov, V.; Vladimirov, V.; Gress, O.; Budnev, N. M.; Ivanov, K.; Tlatov, A.; Gabovich, A.; Yurkov, V.; Sergienko, Yu.; Zalozhnykh, I.

2017-09-01

We report the discovery and multicolour (VRIW) photometry of the rare explosive star MASTER OT J004207.99+405501.1 - a luminous red nova - in the Andromeda galaxy M31N2015-01a. We use our original light curve acquired with identical MASTER Global Robotic Net telescopes in one photometric system: VRI during the first 30 d and W (unfiltered) during 70 d. Also, we added published multicolour photometry data to estimate the mass and energy of the ejected shell and we discuss the likely formation scenarios of outbursts of this type. We propose an interpretation of the explosion that is consistent with an evolutionary scenario where the merging of stellar components or the disruption of the common envelope of a close binary can explain some luminous red novae. Radiative hydrodynamic simulations of a luminous red nova were carried out in extended parameter space to fit its light curves. We find that the multicolour passband light curves of the luminous red nova are consistent with an initial common envelope radius of 10 R⊙, a merger mass of 3 M⊙ and an explosion energy of 3 × 1048 erg. As a result, the phenomenon of novae consists of two classes: classical nuclear novae and more rare events (red novae) connected with the loss of compact common envelopes.

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.

The May 18, 1998 Indian Nuclear Test Seismograms at station NIL

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

Walter, W R; Rodgers, A J; Bowers, D

2005-04-11

The last underground nuclear tests were conducted by India and Pakistan in May 1998. Although the Comprehensive Test Ban Treaty has not entered force, an International Monitoring System (IMS), established by the treaty is nearing completion. This system includes 170 seismic stations, a number of them originally established by IRIS. The station IRIS station NIL (Nilore, Pakistan) is close to a planned IMS primary station and recorded some very interesting seismograms from the May 18, 1998 Indian test. We carefully calibrated the path to NIL using a prior Mw 4.4 that occurred on April 4, 1995 about 110 km northmore » of the Indian test site. We used joint epicentral location techniques along with teleseismic P waves and regional surface waves to fix the epicenter, depth, mechanism and moment of this event. From these we obtained a velocity model for the path to NIL and created explosion synthetic seismograms to compare with the data. Interestingly the observed Rayleigh waves are reversed, consistent with an implosion rather than an explosion source. The preferred explanation is that the explosion released tectonic stress near the source region, which can be modeled as a thrust earthquake of approximate Mw 4.0 plus a pure explosion. This tectonic release is sufficient to completely dominate the Rayleigh waves and produce the observed signal (Walter et al. 2005). We also examined the explosion at high frequencies of 6 6-8 Hz where many studies have shown that relative P/S amplitudes can discriminate explosions from a background of earthquakes (Rodgers and Walter, 2002). Comparing with the April 4 1995 earthquake we see the classic difference of relatively large P/S values for the explosion compared to the earthquakes despite the complication of the large tectonic release during the explosion.« less

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

Keller, David C.; Fresquez, Philip R.; Hansen, Leslie A.

Breeding bird abundance, species richness, evenness, diversity, composition, productivity, and survivorship were determined near a high-explosive detonation site at Los Alamos National Laboratory, New Mexico, USA, during pre-operation (1997-1999) and operation (2000-2014) periods. The operation periods consisted of detonations (<23 kg in yield and <3 per breeding season) in open air (2000-2002), within foam containment (2003-2006) and within steel vessel containment (2007-2014) systems; the latter two were employed to reduce noise and dispersal of high-explosives residues. A total of 2952 bird captures, representing 80 species, was recorded during 18 years of mist net operations using the Monitoring Avian Productivity andmore » Survivorship protocol. Individuals captured were identified to species, aged, sexed, and banded during May through August of each year. There were no significant differences (p > 0.05) in mean avian abundance and species evenness in any of the operation periods as compared with the pre-operation period. Species richness and diversity were significantly higher (p < 0.05) during the vessel containment period (2007-2014) than the pre-operation period. The time period of this study coincided with a wildfire (2000), a bark beetle infestation (2002), and two periods of drought (Nov 1999-Mar 2004 and Dec 2005-Dec 2014) that affected the study area. Furthermore, analysis of aerial photos determined that the average percent canopy cover of mature ponderosa pines (Pinus ponderosa) within 100 feet of mist net sites declined from 12% to 3% between 1991 and 2014 and the percent cover of shrubs slightly increased.« less

Constraining the Single-degenerate Channel of Type Ia Supernovae with Stable Iron-group Elements in SNR 3C 397

NASA Astrophysics Data System (ADS)

Dave, Pranav; Kashyap, Rahul; Fisher, Robert; Timmes, Frank; Townsley, Dean; Byrohl, Chris

2017-05-01

Recent Suzaku X-ray spectra of supernova remnant (SNR) 3C 397 indicate enhanced stable iron group element abundances of Ni, Mn, Cr, and Fe. Seeking to address key questions about the progenitor and explosion mechanism of 3C 397, we compute nucleosynthetic yields from a suite of multidimensional hydrodynamics models in the near-Chandrasekhar-mass, single-degenerate paradigm for Type Ia supernovae (SNe Ia). Varying the progenitor white dwarf (WD) internal structure, composition, ignition, and explosion mechanism, we find that the best match to the observed iron peak elements of 3C 397 are dense (central density ≥6 × 109 g cm-3), low-carbon WDs that undergo a weak, centrally ignited deflagration, followed by a subsequent detonation. The amount of 56Ni produced is consistent with a normal or bright normal SNe Ia. A pure deflagration of a centrally ignited, low central density (≃2 × 109 g cm-3) progenitor WD, frequently considered in the literature, is also found to produce good agreement with 3C 397 nucleosynthetic yields, but leads to a subluminous SN Ia event, in conflict with X-ray line width data. Additionally, in contrast to prior work that suggested a large supersolar metallicity for the WD progenitor for SNR 3C 397, we find satisfactory agreement for solar- and subsolar-metallicity progenitors. We discuss a range of implications our results have for the single-degenerate channel.

Using amphiphilic pseudo amino acid composition to predict enzyme subfamily classes.

PubMed

Chou, Kuo-Chen

2005-01-01

With protein sequences entering into databanks at an explosive pace, the early determination of the family or subfamily class for a newly found enzyme molecule becomes important because this is directly related to the detailed information about which specific target it acts on, as well as to its catalytic process and biological function. Unfortunately, it is both time-consuming and costly to do so by experiments alone. In a previous study, the covariant-discriminant algorithm was introduced to identify the 16 subfamily classes of oxidoreductases. Although the results were quite encouraging, the entire prediction process was based on the amino acid composition alone without including any sequence-order information. Therefore, it is worthy of further investigation. To incorporate the sequence-order effects into the predictor, the 'amphiphilic pseudo amino acid composition' is introduced to represent the statistical sample of a protein. The novel representation contains 20 + 2lambda discrete numbers: the first 20 numbers are the components of the conventional amino acid composition; the next 2lambda numbers are a set of correlation factors that reflect different hydrophobicity and hydrophilicity distribution patterns along a protein chain. Based on such a concept and formulation scheme, a new predictor is developed. It is shown by the self-consistency test, jackknife test and independent dataset tests that the success rates obtained by the new predictor are all significantly higher than those by the previous predictors. The significant enhancement in success rates also implies that the distribution of hydrophobicity and hydrophilicity of the amino acid residues along a protein chain plays a very important role to its structure and function.

Ethylenediamine salt of 5-nitrotetrazole and preparation

DOEpatents

Lee, K.; Coburn, M.D.

1984-05-17

The ethylenediamine salt of 5-nitrotetrazole has been found to be useful as an explosive alone and in eutectic mixtures with ammonium nitrate and/or other explosive compounds. Its eutectic with ammonium nitrate has been demonstrated to behave in a similar manner to a monomolecular explosive such as TNT, and is less sensitive than the pure salt. Moreover, this eutectic mixture, which contains 87.8 mol% of ammonium nitrate, is close to the CO/sub 2/-balanced composition of 90 mol%, and has a relatively low melting point of 110.5 C making it readily castable. The ternary eutectic system containing the ethylenediamine salt of 5-nitrotetrazole, ammonium nitrate and ethylenediamine dinitrate has a eutectic temperature of 89.5 C and gives a measured detonation pressure of 24.8 GPa, which is 97.6% of the calculated value. Both the pure ethylenediamine salt and its known eutectic compounds behave in substantially ideal manner. Methods for the preparation of the salt are described.

Ethylenediamine salt of 5-nitrotetrazole and preparation

DOEpatents

Lee, Kien-yin; Coburn, Michael D.

1985-01-01

Ethylenediamine salt of 5-nitrotetrazole and preparation. This salt has been found to be useful as an explosive alone and in eutectic mixtures with ammonium nitrate and/or other explosive compounds. Its eutectic with ammonium nitrate has been demonstrated to behave in a similar manner to a monomolecular explosive such as TNT, and is less sensitive than the pure salt. Moreover, this eutectic mixture, which contains 87.8 mol % of ammonium nitrate, is close to the CO.sub.2 -balanced composition of 90 mol %, and has a relatively low melting point of 110.5 C. making it readily castable. The ternary eutectic system containing the ethylenediamine salt of 5-nitrotetrazole, ammonium nitrate and ethylenediamine dinitrate has a eutectic temperature of 89.5 C. and gives a measured detonation pressure of 24.8 GPa, which is 97.6% of the calculated value. Both the pure ethylenediamine salt and its known eutectic compounds behave in substantially ideal manner. Methods for the preparation of the salt are described.