Journal articles on the topic 'Mass explosion'
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Filippov, Vladimir, Andrey Eremenko, and Igor Mokrousov. "GEOTECHNOLOGY IMPACT ON SEISMIC ACTIVITY OF THE AREA DURING MINING PROTECTIVE PILLAR IN CONDITIONS OF SHEREGESH DEPOSIT." Interexpo GEO-Siberia 2, no. 5 (2019): 75–80. http://dx.doi.org/10.33764/2618-981x-2019-2-5-75-80.
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Analysis of blasting works during reserves mining of protective pillar of level-and-room mining and sublevel mining with application of mobile machinery is carried out. It is established that high power explosions, carried out within border of protective pillar, longtime impact on rock solid (up to 2 days and more). Each explosion forms seismic active zone in which shocks occur on the distance up to 400v and more. Converse to technology of sublevel caving with application of mobile machinery has excepted carrying out explosions with large mass of explosive materials (10t and more). Through a month, 20-30 explosions are carried out with mass of explosive material from 800-900kg up to 3000-3500 kg. Increasing of explosion number causes to the explosions produce seismic active zone and Impact to solid condition and near workings. But reduction of mass of explosive materials has caused to low frequent event. Mainly seismic events of 1 and 2 class happen.
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Bjelovuk, Ivana D. "Estimation of the explosive mass based on the surface explosion crater on asphalt." Tehnicki vjesnik - Technical Gazette 22, no. 1 (2015): 227–32. http://dx.doi.org/10.17559/tv-20130928113332.
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Kukfisz, Bożena, and Robert Piec. "The Fire and Explosion Hazard of Coloured Powders Used during the Holi Festival." International Journal of Environmental Research and Public Health 18, no. 21 (October 21, 2021): 11090. http://dx.doi.org/10.3390/ijerph182111090.
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During the world-famous Holi festival, people throw and smear each other with a colored powder (Holi color, Holi powder, Gulal powder). Until now, adverse health and environmental effects (skin and eye irritation, air pollution, and respiratory problems) have been described in the available literature. However, the literature lacks data on the flammable and explosive properties of these powders during mass events, despite the fact that burns, fires, and explosions during the Holi festival have taken place many times. The aim of the article is to present the fire and explosion parameters of three currently used Holi dust and cornflour dust types as reference dust. The minimum ignition temperature of the dust layer and dust cloud, the maximum explosion pressure and its maximum rate of growth over time, the lower explosion limit, the limit of oxygen concentration, and the minimum ignition energy were determined. Tests confirmed that the currently available Holi powders should be classified as flammable dusts and low-explosive dusts. The likelihood of a fire or explosion during mass incidents involving a Holi dust-air mixture is high.
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Zotkin, D. A., M. A. Kislov, and K. N. Krupin. "Forensic injury characteristics in explosive trauma mass case." Bulletin of the Medical Institute "REAVIZ" (REHABILITATION, DOCTOR AND HEALTH), no. 1 (April 13, 2021): 17–20. http://dx.doi.org/10.20340/vmi-rvz.2021.1.morph.1.
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The use of improvised explosive devices for terrorist purposes in crowded areas forms explosive trauma as a form of violent peacetime trauma. The forensic aspect of such events is associated with the reconstruction of explosion circumstances, in which the structure of organs and tissues damage of the body is important, as morphological equivalents of damaging factors impact. Based on the archival material of forensic medical examinations, identical mass cases of explosive trauma are summarized, in the assessment of which the characteristics of explosion damaging factors and the damage to the body corresponding to their effects are given, which can be used in forensic practice to establish the conditions and circumstances of the explosion, as well as the reconstruction of these events.
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Wang, Chuan-hao, Shu-shan Wang, Jing-xiao Zhang, and Feng Ma. "Pressure Load Characteristics of Explosions in an Adjacent Chamber." Shock and Vibration 2021 (January 21, 2021): 1–9. http://dx.doi.org/10.1155/2021/3726306.
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To learn more about dynamite explosions in confined spaces, we focused on the chamber adjacent to the main chamber, the main chamber being the location of the explosion. We investigated the characteristics of two damaging pressure loads: first reflected shock wave and quasistatic pressure. In this work, we analyzed the characteristics of the first reflected shock wave and the quasistatic pressure formed by the explosion of the chamber charge. Simulated chamber explosion experiments were carried out, where high-frequency piezoelectric sensors were used to measure the first reflected shock wave, and low-frequency piezo-resistive sensors were used to measure the quasistatic pressure. Valid and reasonable experimental data were obtained, and the experimental values of the pressure load were compared with those calculated from the classical model. The results showed that when the main chamber was partially damaged by the explosion load, the adjacent chambers were not subjected to the shock wave load, and the quasistatic pressure load was less than that in the main chamber. The presence of adjacent chambers did not affect the shock wave load in the main chamber. Using the mass of the explosive and the blast distance as input parameters, the internal explosion shock wave load parameters, including those in adjacent chambers, can be calculated. The presence of the adjacent chamber did not affect the theoretically calculated quasistatic overpressure peak in the main chamber. Using the mass of the explosive and the spatial volume of the chamber as input parameters, the quasistatic pressure load parameters of the internal explosion can be calculated, including those in the adjacent chambers.
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Chevalier, R. A. "Supernovae and Stellar Mass Loss." Highlights of Astronomy 7 (1986): 599–609. http://dx.doi.org/10.1017/s1539299600007000.
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AbstractType I supernovae can be modeled as the carbon deflagration of white dwarfs and Type II supernovae as the explosions of massive stars with hydrogen envelopes. The massive stars at the ends of their lives are expected to be red supergiants, which are observed to have slow, dense winds. The interaction of the supernova kinetic energy and radiation with the circumstellar gas gives rise to observational phenomena at a range of wavelengths. Additional phenomena, such as a scattered light echo, are predicted. While the light from a Type II supernova near maximum light is probably from energy deposited in the initial explosion, there is now good evidence that the radioactive decay of 56Co powers the emission at late times. It was been noted that the explosions of massive stars without hydrogen envelopes would be quite unlike normal Type II supernovae. There is now good evidence for such explosions – SN1985f and the class of peculiar Type I supernovae. It is suggested that these supernovae be called Type III with the spectroscopic definition of a) no H lines and b) broad [01] lines at late times. That not all very massive star explosions are of this type is indicated by SN1961v, which was probably a very massive explosion, but in which hydrogen was present.
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Wang, Chuan-hao, Shu-shan Wang, and Jing-xiao Zhang. "Pressure Load Characteristics of Nonideal Explosives in a Simulation Cabin." Shock and Vibration 2019 (September 24, 2019): 1–8. http://dx.doi.org/10.1155/2019/6862134.
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In this study, an aluminum-containing charge was exploded in an enclosed simulation cabin to explore the characteristics of two types of damaging pressure loads formed by internal explosions: the first incident shock wave and the quasistatic pressure. A high-frequency piezoelectric sensor was used to measure the first incident shock wave and a low-frequency piezoresistive sensor was used to measure the quasistatic pressure. After obtaining effective experimental data, the experimental results were compared with the values obtained by the classical calculation model. The results show that the pressure loads generated by the internal explosions from the ideal explosive and the aluminum-containing explosive share similar load characteristics, given the same mass and benchmark explosive. The difference between the two explosives primarily lies in the amplitude of the load parameters. The aluminum-containing explosive has lower first incident shock wave and higher quasistatic pressure than that of the ideal explosive. For the peak overpressure of the first incident shock wave, the explosion shock wave load parameters of the aluminum-containing explosive, which are calculated based on the explosion heat theory, are higher than the measured values. The peak quasistatic overpressure is directly related to the total energy released by the explosion; however, they are hardly correlated with the reaction process. Therefore, the aerobic postcombustion reaction of the aluminum-containing explosive does not affect the analysis and calculation of the peak quasistatic overpressure. As a result, given the heat value of the explosive, the peak quasistatic overpressure of the explosive can accurately be obtained.
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Katanov, Igor. "The Change of the Spatial Parameters of the Destruction of the Rock mass by Borehole Charge with Low-Density Tamping." E3S Web of Conferences 41 (2018): 01018. http://dx.doi.org/10.1051/e3sconf/20184101018.
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Explosive destruction of the rock formation is substantiated by several theories developed by well-known scientists. The improvement of quality of preparation of rock mass to excavation, by an excavator without an increase in the value of specific consumption of explosives is important in the present time. Traditionally, to increase the impact time of detonation products on the rock hard tamping was used. The problem is in the rational redistribution of the explosion energy due to the use of a borehole charge, and in particular, in the tamping of low-density, porous materials. The more intensive attenuation of the mass velocity of particles in the material of such tamping in comparison with the mass velocity of the rock mass particles contributes to the well channel compression and increases the impact time of detonation products on the rock mass. As a result of redistribution of energy of detonation products, the specific impulse of explosion increases. The value of the radius of the controlled crushing zone increases by more than 1.6 times. The results of industrial explosions in coal mines have confirmed the theoretical reasoning.
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Lazarević, Miloš, Bogdan Nedić, Jovica Bogdanov, and Stefan Đurić. "Determination of the critical distance in the procedure of explosive welding." Vojnotehnicki glasnik 68, no. 4 (2020): 823–44. http://dx.doi.org/10.5937/vojtehg68-26683.
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Introduction/purpose: When performing the explosive welding procedure, for the safety of workers, it is necessary to take into account the minimum distance between the workers and the place of explosion at the time of explosion. Negligence can cause temporary hearing loss, rupture of the eardrum and in some cases even the death of workers. The aim of this paper is to determine the critical distance based on the mass of explosive charge required for explosive welding, provided that the limit pressure is 6.9 kPa in the case of temporary hearing loss and 35 kPa in the case of eardrum rupture. This paper does not take into account other effects of the explosion than those caused by the shock wave. Methods: Depending on the type of explosion, the equivalent explosive mass was calculated. Based on the equivalent explosive mass and the limit pressure, the minimum distances were calculated using the Sadovsky and Kingery-Bulmash equations. Results: The corresponding tables show the results of the calculation of the critical distance of workers from the place of the explosion when there may be temporary hearing loss or rupture of the eardrum. The calculated value of the critical explosion distance by the Kingery-Bulmash method, under the condition of the maximum pressure for temporary hearing loss, is 5.62% lower than the distance value obtained by the Sadovsky method while the value of the critical explosion distance calculated by the Kingery-Bulmash method, under the condition of the maximum pressure for eardrum rupture, is 7.83% lower than the value obtained by the Sadovsky method. Conclusion: The results of the calculation showed that the critical distance from the explosion can be successfully calculated and that the obtained values have small differences depending on the applied calculation method.
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Xie, Zui Wei, Xin Yue Wu, and Qiang Wan. "Relation between Actual Mass and Simulation Mass of Far-Field Underwater Explosion." Applied Mechanics and Materials 127 (October 2011): 350–54. http://dx.doi.org/10.4028/www.scientific.net/amm.127.350.
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The far-filed underwater explosive shock wave pressure and impulse is simulated by the FEM code LS-DYNA, and the simulation results are found having rapid decay characteristic through compared with the empirical results. Based on this phenomenon, the relations, whose validity is verified through a computation instance, between simulation mass and actual mass under given initial conditional is obtained by using curve fitting. Using those equations, the accuracy of LS-DYNA to simulate far-field underwater explosive can significantly be increased, thus the ability of this code to simulate far-field underwater explosion is enhanced.
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Gogilashvili, Mariam, Jeremiah W. Murphy, and Quintin Mabanta. "Explosion energies for core-collapse supernovae I: analytic, spherically symmetric solutions." Monthly Notices of the Royal Astronomical Society 500, no. 4 (November 13, 2020): 5393–407. http://dx.doi.org/10.1093/mnras/staa3546.
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ABSTRACT Recent multidimensional simulations of core-collapse supernovae are producing successful explosions and explosion-energy predictions. In general, the explosion-energy evolution is monotonic and relatively smooth, suggesting a possible analytic solution. We derive analytic solutions for the expansion of the gain region under the following assumptions: spherical symmetry, one-zone shell, and powered by neutrinos and α particle recombination. We consider two hypotheses: (I) explosion energy is powered by neutrinos and α recombination and (II) explosion energy is powered by neutrinos alone. Under these assumptions, we derive the fundamental dimensionless parameters and analytic scalings. For the neutrino-only hypothesis (II), the asymptotic explosion energy scales as $E_{\infty } \approx 1.5 M_\mathrm{ g}\nu _0^2 \eta ^{2/3}$, where Mg is the gain mass, $\nu _0$ is the free-fall velocity at the shock, and η is a ratio of the heating and dynamical time-scales. Including both neutrinos and recombination (hypothesis I), the asymptotic explosion energy is $E_{\infty } \approx M_g \nu _0^2 (1.5\eta ^{2/3} + \beta f(\rho _0))$, where β is the dimensionless recombination parameter. We use Bayesian inference to fit these analytic models to simulations. Both hypotheses fit the simulations of the lowest progenitor masses that tend to explode spherically. The fits do not prefer hypothesis I or II; however, prior investigations suggest that α recombination is important. As expected, neither hypothesis fits the higher mass simulations that exhibit aspherical explosions. In summary, this explosion energy theory is consistent with the spherical explosions of low progenitor masses; the inconsistency with higher progenitor-mass simulations suggests that a theory for them must include aspherical dynamics.
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Nykyforova, Valentyna, Ernest Yefremov, Ihor Kratkovskyi, and Volodymyr Kurinnyi. "Influence rocks mass and explosives properties on dissipative energy losses during blasting." E3S Web of Conferences 109 (2019): 00064. http://dx.doi.org/10.1051/e3sconf/201910900064.
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The factors affecting the energy explosion loss on rock crushing on con-tact with explosives have been established. This makes it possible to substantiate ways to increase low explosion efficiency. Theoretical estimates of the explosion energy losses during the rocks destruction have been carried out taking into account the explosives properties and heterogeneities in the rocks structure. It has been established that homogeneities in the form of mineral grains of various strengths determine the mechanism of their destruction and crushing during blusting. A thermodynamic loss has been estimated during the expansion of gaseous detonation products, on which the maximum explosion work depends. These losses characterize the theoretical possibility of the transfer of energy stored in an explosive into mechanical work. The explosion losses associated with the origination of shock waves in rocks are also have been determined.
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Aoki, Yusuke, Kazuhito Fujiwara, Tetsuyuki Hiroe, and Hidehiro Hata. "A Study on an Initiation Technique of Small Amount of Explosive." Materials Science Forum 673 (January 2011): 203–8. http://dx.doi.org/10.4028/www.scientific.net/msf.673.203.
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High explosives are useful material to generate great amount of energy in short time. Since controlling their releasing energy is hard, the use of explosive is limited to specific fields and industries. However, the reduction of the explosive powder mass uses at a time makes the handling safe. And use of explosives in a continuous producing process leads the new utility of the explosion. Based on this concept, we enclosed small mass explosives with a polyethylene sheet and initiate them by using metallic foil explosion. We have also developed the system that can generate small explosion continuously. Since it was not easy to initiate a small amount of explosive steady, we had initiated them by metallic foil explosion using a power-supply unit of capacitor bank with 2500J (20kV). In present study, we tested the initiation of a small amount of explosive using a comparatively small power-supply unit of capacitor bank with 4.5J (600V) and that of 2J (1kV) to apply to the general use. In this paper, result of experiments and the conclusions are shown. We observed the perfectness of explosion by using omnidirectional microphone. It is concluded that initiation of explosives enclosed with polyethylene sheet by small power supply unit at 2J (1kV) is possible, while the explosion was not perfect.
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Nakayama, Yoshio, Kunihiko Wakabayashi, Tomoharu Matsumura, and Mitsuaki Iida. "Blast Wave Effects from Internal Explosion of Subsurface Explosive Storage Facility." Applied Mechanics and Materials 82 (July 2011): 663–68. http://dx.doi.org/10.4028/www.scientific.net/amm.82.663.
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To reduce safe distance such as inhabited building distance (IBD), a new type magazine, which is referred to as a subsurface magazine, has been proposed and the explosion effects have been discussed. We have conducted explosive tests by using relatively large scale models (23 kg and 78 kg in mass) and examined mass effect (scale effect) of blast waves caused by explosion of high explosives. The magazines were composed of a arch-type explosive storage room with a line hinge along the top of the roof of the wall, a square passage way to ground which will release the blast wave. Explosion hazards from the explosion of subsurface magazines were collected to understand the characteristics of airblast, fragments, and ground shocks. Safety criteria for the subsurface magazine are discussed based on the experimental results.
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Song, Juan, and Shu Cai Li. "Study on Numerical Simulation of Explosion in Soil Based on Fluid-Solid Coupling Arithmetic." Applied Mechanics and Materials 580-583 (July 2014): 2916–19. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.2916.
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Numerical simulations play a significant role in explosion in a mass of soil due to an underground explosive. Common methods available in hydrocode for fluid-solid coupling process are contact algorithm, Lagrange algorithm, and Arbitrary Lagrange-Euler (ALE) algorithm. A numerical simulation of explosion process with concentrated charge in a mass of soil was carried out by using three methods in this paper. The dynamic response of soil medium, the formation and development law of explosion cavity and the explosion wave propagation law in soil were simulated. Merits and drawbacks of three different methods are analyzed in the aspect of modeling, simulation results and computing cost.
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Yan, Qiushi, Chen Liu, Jun Wu, Jun Wu, and Tieshuan Zhuang. "Experimental and Numerical Investigation of Reinforced Concrete Pile Subjected to Near-Field Non-Contact Underwater Explosion." International Journal of Structural Stability and Dynamics 20, no. 06 (May 30, 2020): 2040003. http://dx.doi.org/10.1142/s0219455420400039.
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High-pile wharf is an important port structure and may suffer from accidental explosions or terrorist bombing attack during the service life. The reinforced concrete (RC) pile is one of the popular vertical load-bearing piles of high-pile wharf structure. As a main load-bearing member of the high-pile wharf structure, the damage of RC pile due to underwater explosive may cause subsequently progressive collapse of the whole structure. In this paper, the dynamic response and failure mode of RC pile in high-pile wharf structure under the near-field non-contact underwater explosion are investigated using a combined experimental and numerical study. First, a typical RC pile was designed and tested for the near-field non-contact underwater explosion. The failure mode and damage of the RC pile specimen were obtained and analyzed. Second, the numerical model of the RC pile under near-field non-contact underwater explosion was established by adopting the commercial software AUTODYN, and then validated based on experimental results. It was shown that the results from numerical model and experimental test compared very well in terms of the damage pattern and lateral displacement. Furthermore, the full-scale numerical model of the RC pile for the near-field non-contact underwater explosion was developed based on the validated numerical model to investigate the damage pattern and failure mode of RC pile under varied underwater explosives. Lastly, the safety distance for the RC pile for the underwater explosion loading with consideration of different explosive mass, the explosive depth and the concrete strength was suggested. The outcome of this study presented reference for analysis, assessment and design of the type of RC pile for high-pile wharf structure subjected to near-field non-contact underwater explosion.
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Chen, Fei, Jinfeng Mao, Jin Zhou, Pumin Hou, Liyao Liu, and Shangyuan Chen. "Thermal Environment inside a Tunnel after Thermobaric Explosion." Shock and Vibration 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/5427485.
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The outstanding thermal damage effect of thermobaric explosive (TBX) is enhanced in closed or semiclosed spaces, which may pose a serious threat to the security of people sheltered in tunnels or other protective engineering. In order to investigate the thermal environment inside a tunnel after thermobaric explosion, we developed a damage evaluation method for the thermal radiation of explosion fireballs in tunnels; secondly, the air temperature distribution inside a tunnel shortly after explosion was theoretically analyzed; finally, the dynamic thermal environment after the explosion and the influences of TBXs mass and initial ground temperature on it in cases of open and blocked tunnels were numerically simulated with the FLUENT software. The results show that the fireball thermal radiation damage occurs mainly in the vicinity of the explosion source. The air temperature inside a tunnel shortly after the explosion decreases continuously with increasing distance from the explosion source and finally reaches the initial air temperature. The decay rate of air temperature inside a tunnel is slower in the blocked case, which increases the probability of causing a secondary fire disaster. The increase of explosive mass and the initial ground temperature favor the high-temperature performance of TBX, especially for the blocked tunnel.
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Lopez, R., J. Isern, J. Labay, and R. Canal. "Explosion of White Dwarfs." International Astronomical Union Colloquium 93 (1987): 413–17. http://dx.doi.org/10.1017/s0252921100105147.
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AbstractWe present models for Type I supernova light curves based on the explosion of partially solid white dwarfs in close binary systems. Studies of such explosions show that they leave bound remnants of different size. Our results reproduce quite well the maximun luminosities, the expansion velocities and the shape of the light curve. As the two basic papameters that govern the light curve, the ejected mass and the mass of 56Ni produced, are variable our models reproduce the slow and fast subclasses of “classical” Type I supernovae.
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Sim, Stuart A., Friedrich K. Röpke, Markus Kromer, Michael Fink, Ashley J. Ruiter, Ivo R. Seitenzahl, Rüdiger Pakmor, and Wolfgang Hillebrandt. "Type Ia Supernovae from Sub-Chandrasekhar Mass White Dwarfs." Proceedings of the International Astronomical Union 7, S281 (July 2011): 267–74. http://dx.doi.org/10.1017/s1743921312015189.
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AbstractWe argue that detonations of sub-Chandrasekhar mass white dwarfs can lead to bright explosions with light curves and spectra similar to those of observed Type Ia supernovae. Given that binary systems containing accreting sub-Chandrasekhar mass white dwarfs should be common, this suggests that a non-negligible fraction of the observed Type Ia supernova rate may arise from sub-Chandrasekhar mass explosions, if they can be ignited. We discuss aspects of how such explosions might be realized in nature and both merits and challenges associated with invoking sub-Chandrasekhar mass explosion models to account for observed Type Ia supernovae.
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Burrows, Adam, David Radice, David Vartanyan, Hiroki Nagakura, M. Aaron Skinner, and Joshua C. Dolence. "The overarching framework of core-collapse supernova explosions as revealed by 3D fornax simulations." Monthly Notices of the Royal Astronomical Society 491, no. 2 (November 28, 2019): 2715–35. http://dx.doi.org/10.1093/mnras/stz3223.
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ABSTRACT We have conducted 19 state-of-the-art 3D core-collapse supernova simulations spanning a broad range of progenitor masses. This is the largest collection of sophisticated 3D supernova simulations ever performed. We have found that while the majority of these models explode, not all do, and that even models in the middle of the available progenitor mass range may be less explodable. This does not mean that those models for which we did not witness explosion would not explode in Nature, but that they are less prone to explosion than others. One consequence is that the ‘compactness’ measure is not a metric for explodability. We find that lower-mass massive star progenitors likely experience lower-energy explosions, while the higher-mass massive stars likely experience higher-energy explosions. Moreover, most 3D explosions have a dominant dipole morphology, have a pinched, wasp-waist structure, and experience simultaneous accretion and explosion. We reproduce the general range of residual neutron-star masses inferred for the galactic neutron-star population. The most massive progenitor models, however, in particular vis à vis explosion energy, need to be continued for longer physical times to asymptote to their final states. We find that while the majority of the inner ejecta have Ye = 0.5, there is a substantial proton-rich tail. This result has important implications for the nucleosynthetic yields as a function of progenitor. Finally, we find that the non-exploding models eventually evolve into compact inner configurations that experience a quasi-periodic spiral SASI mode. We otherwise see little evidence of the SASI in the exploding models.
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Kutuev, Vyacheslav, Pavel Menshikov, and Sergey Zharikov. "Analysis of blasting seismic impact on underground mining workings under the conditions of the Magnezitovaya mine." E3S Web of Conferences 192 (2020): 01029. http://dx.doi.org/10.1051/e3sconf/202019201029.
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Seismic impact of technological explosions on underground mining workings of the Magnezitovaya mine was assessed. Seismic stability of rocks of the Magnezitovaya mine was determined and safe distances from technological explosions have been calculated by the admissible seismic effect for rocks. URAN and Minimate Plus seismic recorders with three-component seismic receivers were used to establish the dynamic impact on the mine workings. Based on comparison of calculated values and experimental measurements, the recommendations are given for explosive mass limitation at a slowing-down stage at a level of minimum dangerous values for technological explosions in underground mine. It is established that the blasting operations carried out at the Magnezitovaya mine of PAO Magnezit Combine with fan longhole stopping were performed with the seismic impact safety of underground technological explosion and will not lead to the loss of rock mass stability near the underground workings. Relevance of these studies is to ensure industrial safety of underground mining operations.
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Melson, Tobias, Hans-Thomas Janka, Alexander Summa, Robert Bollig, Andreas Marek, and Bernhard Müller. "Exploring the explosion mechanism of core-collapse supernovae in three dimensions." Proceedings of the International Astronomical Union 12, S329 (November 2016): 424. http://dx.doi.org/10.1017/s1743921317001181.
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AbstractWe present the first successful simulations of neutrino-driven supernova explosions in three dimensions (3D) using the Vertex-Prometheus code including sophisticated energy-dependent neutrino transport. The simulated models of 9.6 and 20 solar-mass iron-core stars demonstrate that successful explosions can be obtained in self-consistent 3D simulations, where previous models have failed. New insights into the supernova mechanism can be gained from these explosions. The first 3D model (Melson et al. 2015a) explodes at the same time but more energetically than its axially symmetric (2D) counterpart. Turbulent energy cascading reduces the kinetic energy dissipation in the cooling layer and therefore suppresses neutrino cooling. The consequent inward shift of the gain radius increases the gain layer mass, whose recombination energy provides the surplus for the explosion energy.The second explosion (Melson et al. 2015b) is obtained through a moderate reduction of the neutral-current neutrino opacity motivated by strange-quark contributions to the nucleon spin. A corresponding reference model without these corrections failed, which demonstrates how close current 3D models are to explosion. The strangeness adjustment is meant as a prototype for remaining neutrino opacity uncertainties.
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Ishchenko, Kostiantyn, Volodymyr Konoval, and Liudmyla Lohvyna. "An effective way to rock mass preparation on metallic and nonmetallic quarries Ukraine." E3S Web of Conferences 109 (2019): 00031. http://dx.doi.org/10.1051/e3sconf/201910900031.
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A method in experimental studies and industrial-polygon particular conditions justifying the choice of a rational design of an explosive charge. The comparative results of the evaluation of the stress wave’s amplitudes studies and the character of crushing hard media from the explosion of the charge explosives-variable and constant cross section. The dependences of the particle size distribution of various designs explosive charges destroyed by the explosion are constructed. In industrial conditions, the rationale for the explosive boreholes location according to the massif structure. Adjusted boreholes location grid on rational parameters blasting unit, determined using a novel method of breaking rock complex structure. A new design of a combined borehole charge of variable cross section has been proposed. Industrial tests performed and evaluation of the effectiveness of the proposed method blasting locally fractured rocks and ore deposits on non-metallic minerals. Recommendations on their use are given.
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Lawson, Thomas V., Marco Pignatari, Richard J. Stancliffe, Jacqueline den Hartogh, Sam Jones, Chris L. Fryer, Brad K. Gibson, and Maria Lugaro. "Radioactive nuclei in the early Solar system: analysis of the 15 isotopes produced by core-collapse supernovae." Monthly Notices of the Royal Astronomical Society 511, no. 1 (December 22, 2021): 886–902. http://dx.doi.org/10.1093/mnras/stab3684.
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ABSTRACT Short-lived radioactive isotopes (SLRs) with half-lives between 0.1 and 100 Myr can be used to probe the origin of the Solar system. In this work, we examine the core-collapse supernovae production of the 15 SLRs produced: 26Al, 36Cl, 41Ca, 53Mn, 60Fe, 92Nb, 97Tc, 98Tc, 107Pd, 126Sn, 129I, 135Cs, 146Sm, 182Hf, and 205Pb. We probe the impact of the uncertainties of the core-collapse explosion mechanism by examining a collection of 62 core-collapse models with initial masses of 15, 20, and 25 M⊙, explosion energies between 3.4 × 1050 and 1.8 × 1052 erg and compact remnant masses between 1.5 and 4.89 M⊙. We identify the impact of both explosion energy and remnant mass on the final yields of the SLRs. Isotopes produced within the innermost regions of the star, such as 92Nb and 97Tc, are the most affected by the remnant mass, 92Nb varying by five orders of magnitude. Isotopes synthesized primarily in explosive C-burning and explosive He-burning, such as 60Fe, are most affected by explosion energies. 60Fe increases by two orders of magnitude from the lowest to the highest explosion energy in the 15 M⊙ model. The final yield of each examined SLR is used to compare to literature models.
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Jankura, Richard, Zuzana Zvaková, and Martin Boroš. "ANALYSIS OF MATHEMATICAL RELATIONS FOR CALCULATION OF EXPLOSION WAVE OVERPRESSURE." Proceedings of CBU in Natural Sciences and ICT 1 (November 16, 2020): 21–27. http://dx.doi.org/10.12955/pns.v1.116.
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The explosion of an explosive system causes primary and secondary effects on people and objects near its site. The most devastating is the pressure effect of the explosion, especially the overpressure. Individual parameters of pressure wave (overpressure size, duration impulse) can be determined by mathematical or virtual modeling or can also be measured under real conditions.
The authors focused on the parameters of the positive phase of the shock wave propagating from the source of the explosion towards the object. The article covers the description and analysis of selected mathematical relations, which are used to determine the magnitude of the explosion overpressure. The results are based on selected formulas. The source of the explosion referred in the study is an explosive system containing a reference explosive trinitrotoluene (TNT). TNT is a military explosive that is used as a reference explosive in technical standards dedicated to the certification of explosion-proof elements, and at the same time, a TNT equivalent is known to allow the mass of an explosive charge to be recalculated.
The results obtained by mathematical modeling according to individual approaches have been compared and the possibilities of using computational models in the area of security management and education of security managers have been identified. The results of the study confirm that prediction of pressure wave parameters at different distances and weights can assist security managers in creating attack scenarios and designing a suitable object protection system.
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Martinez, Laureano, and Melina C. Bersten. "Mass discrepancy analysis for a select sample of Type II-Plateau supernovae." Astronomy & Astrophysics 629 (September 2019): A124. http://dx.doi.org/10.1051/0004-6361/201834818.
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The detailed study of supernovae (SNe) and their progenitors allows a better understanding of the evolution of massive stars and how these end their lives. Despite its importance, the range of physical parameters for the most common type of explosion, the type II supernovae (SNe II), is still unknown. In particular, previous studies of type II-Plateau supernovae (SNe II-P) showed a discrepancy between the progenitor masses inferred from hydrodynamic models and those determined from the analysis of direct detections in archival images. Our goal is to derive physical parameters (progenitor mass, radius, explosion energy and total mass of nickel) through hydrodynamical modelling of light curves and expansion velocity evolution for a select group of six SNe II-P (SN 2004A, SN 2004et, SN 2005cs, SN 2008bk, SN 2012aw, and SN 2012ec) that fulfilled the following three criteria: (1) enough photometric and spectroscopic monitoring is available to allow for a reliable hydrodynamical modelling; (2) a direct progenitor detection has been achieved; and (3) there exists confirmation of the progenitor identification via its disappearance in post-explosion images. We then compare the masses obtained by our hydrodynamic models with those obtained by direct detections of the progenitors to test the existence of such a discrepancy. As opposed to some previous works, we find good agreement between both methods. We obtain a wide range in the physical parameters for our SN sample. We infer presupernova masses between 10 and 23 M⊙, progenitor radii between 400 and 1250 R⊙, explosion energies between 0.2 and 1.4 foe, and 56Ni masses between 0.0015 and 0.085 M⊙. An analysis of possible correlations between different explosion parameters is presented. The clearest relation found is that between the mass and the explosion energy, in the sense that more-massive objects produce higher-energy explosions, in agreement with previous studies. Finally, we also compare our results with previous physical–observed parameter relations widely used in the literature. We find significant differences between both methods, which indicates that caution should be exercised when using these relations.
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Stockinger, G., H.-T. Janka, D. Kresse, T. Melson, T. Ertl, M. Gabler, A. Gessner, et al. "Three-dimensional models of core-collapse supernovae from low-mass progenitors with implications for Crab." Monthly Notices of the Royal Astronomical Society 496, no. 2 (June 15, 2020): 2039–84. http://dx.doi.org/10.1093/mnras/staa1691.
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ABSTRACT We present 3D full-sphere supernova simulations of non-rotating low-mass (∼9 M⊙) progenitors, covering the entire evolution from core collapse through bounce and shock revival, through shock breakout from the stellar surface, until fallback is completed several days later. We obtain low-energy explosions (∼0.5–1.0 × 1050 erg) of iron-core progenitors at the low-mass end of the core-collapse supernova (LMCCSN) domain and compare to a super-AGB (sAGB) progenitor with an oxygen–neon–magnesium core that collapses and explodes as electron-capture supernova (ECSN). The onset of the explosion in the LMCCSN models is modelled self-consistently using the vertex-prometheus code, whereas the ECSN explosion is modelled using parametric neutrino transport in the prometheus-HOTB code, choosing different explosion energies in the range of previous self-consistent models. The sAGB and LMCCSN progenitors that share structural similarities have almost spherical explosions with little metal mixing into the hydrogen envelope. A LMCCSN with less second dredge-up results in a highly asymmetric explosion. It shows efficient mixing and dramatic shock deceleration in the extended hydrogen envelope. Both properties allow fast nickel plumes to catch up with the shock, leading to extreme shock deformation and aspherical shock breakout. Fallback masses of $\mathord {\lesssim }\, 5\, \mathord {\times }\, 10^{-3}$ M⊙ have no significant effects on the neutron star (NS) masses and kicks. The anisotropic fallback carries considerable angular momentum, however, and determines the spin of the newly born NS. The LMCCSN model with less second dredge-up results in a hydrodynamic and neutrino-induced NS kick of >40 km s−1 and a NS spin period of ∼30 ms, both not largely different from those of the Crab pulsar at birth.
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Wang, Wan Peng, Chun Ming Wang, Xing Tao Ren, Yun Xiao Cui, and Ying Liang. "Experimental Research on the Character of Resist Explosion for Reinforced Concrete Structure of Sand Filling." Applied Mechanics and Materials 543-547 (March 2014): 4014–17. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.4014.
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Explosion containment structure (chamber) is used to protect personnel and experimental equipment during the destruction of explosion environmental for research blasting or disposal exploder. Reinforced concrete has advantiage of low cost and simple process in buliding ,so it was usually used of buliding the structure of resist explosion.This paper demonstrates reinforced concrete structures character of resist explosion under envirmonent of filling sand,the hoop strain of structure central cross section were measured loaded by different mass explosive charges,the safe criterion of reinforced concrete structure was obtained. Loaded by the explosion,the damage mechanics of reinforced concrete structure that diameter equal to height was analysed,and the method for avoiding the structure fail was suggest.
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Hernández, Jonay I. González, Rafael Rebolo, and Garik Israelian. "Chemical abundances of secondary stars in low mass X-ray binaries." Proceedings of the International Astronomical Union 2, S238 (August 2006): 43–48. http://dx.doi.org/10.1017/s1743921307004668.
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AbstractLow mass X-ray binaries (LMXBs) offer us an unique opportunity to study the formation processes of compact objects. Secondary stars orbiting around either a black hole or a neutron star could have captured a significant amount of the ejected matter in the supernova explosions that most likely originated the compact objects. The detailed chemical analysis of these companions can provide valuable information on the parameters involved in the supernova explosion such us the mass cut, the amount of fall-back matter, possible mixing processes, and the energy and the symmetry of the explosion. In addition, this analysis can help us to find out the birth place of the binary system. We have measured element abundances of secondary stars in the LMXBs A0620–00, Cen X-4, XTE J1118+480 and Nova Sco 94. We find solar or above solar metalicity for all these systems, what appears to be independent on their locations with respect to the Galactic plane. A comparison of the observed abundances with yields from different supernova explosion together with the kinematic properties of these systems suggest a supernova origin for the compact objects in all of them except for A0620–00, for which a direct collapse cannot be discarded.
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Remez, N., A. Dychko, Y. Besarabets, S. Kraychuk, N. Ostapchuk, and L. Yevtieieva. "Impact Modelling of Explosion of Mixture Explosive Charges on the Environment." Latvian Journal of Physics and Technical Sciences 56, no. 3 (June 1, 2019): 37–49. http://dx.doi.org/10.2478/lpts-2019-0018.
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Abstract The present paper provides the modelling of the explosion of the charges of the traditional (trotyl) and new blended explosive substances: polymix GR1/8 (74 %) + KRUK2 (26 %), compolite GS6, polymix GR4-T10. As a result of the research, it has been established that when using TNT a specific impulse is formed, which is by 40 % more than an explosion of new mixed explosives, and the safe distance from the source of the explosion of such explosives is increased by 25 %–50 %. On the basis of the established dependences of excess pressure, the specific impulse on the type and mass of charge, as well as the distance from the epicenter of the explosion, an engineering method has been developed for calculating dangerous parameters of the explosion impact on the environment.
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Han, Z., and X. Chen. "White dwarf accretion and type Ia supernovae." Proceedings of the International Astronomical Union 8, S290 (August 2012): 117–20. http://dx.doi.org/10.1017/s1743921312019333.
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AbstractType Ia supernovae (SNe Ia) are believed to be thermonuclear explosions of carbon-oxygen white dwarfs at a mass close to the Chandrasekhar limit. However, a white dwarf at birth has a significantly lower mass and needs to accrete mass to grow to the limit for the explosion. Various progenitor models have been proposed and those models play an important role in our understanding of SNe Ia and cosmology.
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Kim, Sang Ho, Seong-Wan Hong, and Rae-Joon Park. "Analysis of Steam Explosion under Conditions of Partially Flooded Cavity and Submerged Reactor Vessel." Science and Technology of Nuclear Installations 2018 (July 5, 2018): 1–12. http://dx.doi.org/10.1155/2018/3106039.
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A steam explosion in a reactor cavity makes a mechanical load of the pressure pulse, which can result in a failure of the containment isolation. To prove the integrity of the containment during the ex-vessel steam explosion, the effects of water conditions on a steam explosion have to be identified, and the impulse of a steam explosion has to be exactly assessed. In this study, the analyses for steam explosions were performed for the conditions of a partially flooded cavity and a submerged-vessel in a pressurized water reactor. The entry velocity of a corium jet for the scale of the test facility was varied to simulate the two plant conditions. The TEXAS-V code was used for simulating the phases of premixing and explosion, and the load of a steam explosion was estimated based on the pressure variation. The impulse of a steam explosion under the condition of a corium jet falling into water without a free-fall height is bigger than that under a free-fall height. The fragmented mass of corium in an explosion phase and the distribution of steam fraction are the main parameters for the total load of the steam explosion. This study is expected to contribute to analyses of a steam explosion for a severe accident management strategy.
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Chugai, Nikolai N., Robert J. Cumming, Sergei I. Blinnikov, Peter Lundqvist, Alexei V. Filippenko, Aaron J. Barth, Angela Bragaglia, Douglas C. Leonard, Thomas Matheson, and Jesper Sollerman. "SN 1994W: Evidence of Explosive Mass Ejection a Few Years Before Explosion." International Astronomical Union Colloquium 192 (2005): 111–15. http://dx.doi.org/10.1017/s0252921100009064.
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SummaryWe present and analyze spectra of the Type IIn supernova 1994W obtained between 18 and 202 days after explosion. During the first 100 days the line profiles are composed of three major components: (i) narrow P Cygni lines with absorption minima at −700 km s−1; (ii) broad emission lines with blue velocity at zero intensity ~ 4000 km s−1; (iii) broad, smooth, extended wings most apparent in Hα. These components are identified with the expanding circumstellar (CS) envelope [5], shocked cool gas in the forward postshock region, and multiple Thomson scattering in the CS envelope, respectively. The absence of broad P Cygni lines from the supernova (SN) is the result of the formation of an optically thick, cool, dense shell at the interface of the ejecta and the CS envelope. Models of the SN deceleration and Thomson scattering wings are used to recover the Thomson optical depth of the CS envelope, τT ≥ 2.5 during first month, its density (n ~ 109 cm-3) and radial extent, ~ (4 — 5) × 1015 cm. The plateau-like SN light curve, which we reproduce by a hydrodynamical model, is powered by a combination of internal energy leakage after the explosion of an extended presupernova (~ 1015 cm) and subsequent luminosity from circumstellar interaction. We recover the pre-explosion kinematics of the CS envelope and find it to be close to homologous expansion with outmost velocity ≈ 1100 km s-1 and a kinematic age of ~ 1.5 yr. The high mass (≈ 0.4 M⊙) and kinetic energy (≈ 2 × 1048 erg) of the CS envelope combined with small age strongly suggest that the CS envelope was explosively ejected only a few years before the SN explosion.
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Rolc, Stanislav, Vladislav Adamík, J. Buchar, and L. Severa. "Plate Response to Buried Charge Explosion." Materials Science Forum 566 (November 2007): 83–88. http://dx.doi.org/10.4028/www.scientific.net/msf.566.83.
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This paper deals with the dynamic response of clamped plate to the loading following from the detonation of buried explosive charge. The cylindrical explosive charges of 8 kg mass has been considered. The numerical analysis is carried out using the LS DYNA finite element code. Numerical results exhibit reasonable agreement with results of controlled explosion experiments. The study is oriented mainly on the effects of structure representations (solids or shells) and of computational mesh size on evaluation of the structure response.
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Zubek, Łukasz, and Mirosław Sobolewski. "The effect of selected inhibitors on the characteristics of wood dust explosion." MATEC Web of Conferences 247 (2018): 00056. http://dx.doi.org/10.1051/matecconf/201824700056.
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The mass concentration of four inhibitors which is required to suppress pine dust explosion were measured in laboratory-scale system. Measurements were conducted using four commercially available additives commonly used to decrease the fire and explosion hazards, three extinguishing powders: BC FOREX C, ABC Favorit X90, BC 101K and rock dust powder consisting calcium carbonate CaCO3 and magnesium carbonate MgCO3. The inhibition effect was investigated by measuring explosion pressure of various dust/powder mixtures using a 20 dm3 sphere by PN-EN 14034. On the basis of pressure-time curves the derivatives of pressure with respect to time (dp/dt), maximum explosion pressure pmax and maximum rate of explosion pressure rise (dp/dt)max were determined. It was found that inhibiting dust explosions with additives of various dry powders is a very effective way to decrease explosion effects. The experimental results have also shown that inhibiting effectiveness is strictly related to chemical composition of the powder. The order of effectiveness was monoammonium phosphate, sodium bicarbonate, potassium bicarbonate and rock dust.
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Glavšić, Milica, and Predrag Elek. "Numerical analysis of the mine blast action on an armored vehicle for different V-hull geometries." Scientific Technical Review 70, no. 1 (2020): 29–35. http://dx.doi.org/10.5937/str2001029g.
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The main objective of this research is to develop a numerical model of vehicle damage caused by an explosion of a mine, as well as to find the most favorable case of V-hull geometry and to point out a possible solution for mitigating the effects of mine explosion on an armored vehicle. Seven different V-hull geometries were considered and structure damage analysis was performed for all seven options. Also, the mass change for different geometries was analyzed. The effect of the mine explosion on the target structure was analyzed using the overpressure function according to the empirical CONWEP model, using Abaqus / Explicit software. An example of an explosion of 8 kg of Composition B acting on a vehicle with a total mass of 8000 kg was analyzed. The vehicle has two main parts - the cabin with mass of 6 t and a V-hull of mass of 2 t. The V-shaped hull in all the examples shown is made of 10 mm thick plates of Hardox 400 steel. The position of the explosive charge is the same for all geometry examples and is 0.6 m below the center of the vehicle. After analysis of the obtained results the most favorable V-hull geometry is determined. The guidelines for the further work and model improvement are suggested.
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Kimura, Satoshi, Hidehiro Hata, Tetsuyuki Hiroe, Kazuhito Fujiwara, and Hideaki Kusano. "Analysis of Explosion Combustion Phenomenon with Ammonium Nitrate." Materials Science Forum 566 (November 2007): 213–18. http://dx.doi.org/10.4028/www.scientific.net/msf.566.213.
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In this study, an explosion combustion phenomenon of ammonium nitrate (ρ=1.7kg/cm3) was used instead of the explosive PETN and the ultra-high-speed destruction phenomenon of aluminum cylinder was analyzed. The mix powder obtained by mixing aluminum powder (ρ=2.7kg/cm3) and ammonium nitrate was used instead of the explosive PETN, and an explosive combustion phenomenon was generated using copper wire explosion by high-voltage capacitor bank (40kV, 12.5 /F). Ammonium nitrate and aluminum powder are kneaded in a combination ratio of 5 : 1 in mass. An aluminum cylinder was destroyed by the phenomenon. The experiments were conducted using various diameters of ammonium nitrate particle and the photographs of the phenomenon were taken by the high-speed camera (IMACON468) and the high-speed video camera (HPV-1). The fragments of aluminum cylinder were collected and their dimensions were measured. The explosion phenomenon and fragments were compared with the result by explosive PETN. This paper presents these experiments and analysis result. And, hydro codes have been applied to simulate the deformation behavior of the aluminum cylinder.
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Tyupin, V. N. "Prediction of the Ground Vibration Rate during Large-scale Explosions in the Underground Conditions." Occupational Safety in Industry, no. 6 (June 2021): 41–45. http://dx.doi.org/10.24000/0409-2961-2021-6-41-45.
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At present, to ensure seismic safety in massive explosions, the analytical dependence of the determination of the vibration velocity of M.A. Sadovsky rock mass is mainly used. This dependence is widely used in the creation of seismic-safe technologies for mineral deposits open-pit and underground mining. However, scientific research and production experience showed that the rate of oscillation depends on the energy parameters of the explosive, the diameter and length of its charges, the number of simultaneously exploded charges, the number of deceleration stages, the deceleration interval, etc. The purpose of this article is to predict the speed fluctuations of the massif on the earth surface when conducting the underground explosions depending on the parameters of large-scale explosions and physical-technical properties of the rock masses in the areas of explosion of the protected object. The formulas for calculating the velocity of rock mass on the earth surface during large-scale explosions in the underground conditions are substantiated and presented. The formulas were used for calculating the vibration velocities of the rock mass on the earth surface in accordance with the parameters of drilling and blasting operations during large-scale explosions in the mines of GK VostGOK. Comparison of theoretical (calculated) data and the results of actual measurements indicates their convergence. By changing the controlled parameters in the calculation formulas, it is possible to quantitatively reduce the seismic effect of a large-scale explosions on the protected objects. Further research will be aimed at studying the influence of tectonic faults, artificial contour crevices, filling massif or mined-out space on the rate of seismic-explosive vibrations during blasting operations in the mines. The research results can be used in the preparation of rules for conducting large-scale explosions at the underground mining.
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Hashimoto, M., K. Nomoto, T. Tsujimoto, and F. K. Thielemann. "Supernova Nucleosynthesis in Massive Stars." International Astronomical Union Colloquium 145 (1996): 157–64. http://dx.doi.org/10.1017/s0252921100008022.
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Presupernova evolution and explosive nucleosynthesis in massive stars for main-sequence masses from 13 Mʘ to 70 Mʘ are calculated. We examine the dependence of the supernova yields on the stellar mass, 12C(α, γ)16O rate, and explosion energy. The supernova yields integrated over the initial mass function are compared with the solar abundances.
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Mkrtychev, Oleg, and Anton Savenkov. "MODELING OF BLAST EFFECTS ON UNDERGROUND STRUCTURE." International Journal for Computational Civil and Structural Engineering 15, no. 4 (December 29, 2019): 111–22. http://dx.doi.org/10.22337/2587-9618-2019-15-4-111-122.
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Modeling of the impact of a point explosion shock wave on a soil mass and an underground structure at different locations of the explosion epicenter from the ground surface was performed. The study of the stress- strain state of soils was carried out usi ng a nonlinear dynamic method and a fully coupled numerical model, including various models of materials. The result of numerical modeling showed the adequacy of the adopted numerical calculation methods. The findings showed that solving the problem in a nonlinear dynamic formulation allows obtaining the parameters of the shock wave at different depths from the explosion center, as well as obtaining a complete picture of the interaction of the shock wave with the underground structure in surface and underground explosions.
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Martinez, L., J. P. Anderson, M. C. Bersten, M. Hamuy, S. González-Gaitán, M. Orellana, M. Stritzinger, et al. "Type II supernovae from the Carnegie Supernova Project-I." Astronomy & Astrophysics 660 (April 2022): A42. http://dx.doi.org/10.1051/0004-6361/202142555.
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Type II supernovae (SNe II) show great photometric and spectroscopic diversity which is attributed to the varied physical characteristics of their progenitor and explosion properties. In this study, the third of a series of papers where we analyse a large sample of SNe II observed by the Carnegie Supernova Project-I, we present correlations between their observed and physical properties. Our analysis shows that explosion energy is the physical property that correlates with the highest number of parameters. We recover previously suggested relationships between the hydrogen-rich envelope mass and the plateau duration, and find that more luminous SNe II with higher expansion velocities, faster declining light curves, and higher 56Ni masses are consistent with higher energy explosions. In addition, faster declining SNe II (usually called SNe IIL) are also compatible with more concentrated 56Ni in the inner regions of the ejecta. Positive trends are found between the initial mass, explosion energy, and 56Ni mass. While the explosion energy spans the full range explored with our models, the initial mass generally arises from a relatively narrow range. Observable properties were measured from our grid of bolometric LC and photospheric velocity models to determine the effect of each physical parameter on the observed SN II diversity. We argue that explosion energy is the physical parameter causing the greatest impact on SN II diversity, that is, assuming the non-rotating solar-metallicity single-star evolution as in the models used in this study. The inclusion of pre-SN models assuming higher mass loss produces a significant increase in the strength of some correlations, particularly those between the progenitor hydrogen-rich envelope mass and the plateau and optically thick phase durations. These differences clearly show the impact of having different treatments of stellar evolution, implying that changes in the assumption of standard single-star evolution are necessary for a complete understanding of SN II diversity.
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Domínguez, Inma, Luciano Piersanti, Eduardo Bravo, Oscar Straniero, and Sergio Cristallo. "Type Ia SN progenitors: pre-explosion phase in nearly Chandrasekhar mass WDs." EPJ Web of Conferences 260 (2022): 06001. http://dx.doi.org/10.1051/epjconf/202226006001.
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Type Ia supernovae are used as distance indicators to measure the expansion rate of the Universe and to constrain the nature of dark energy. Current and upcoming surveys will allow to extend supernova Hubble diagrams to higher redshifts and to improve further their statistics. It is accepted that Type Ia supernovae are thermonuclear explosions of carbon-oxygen white dwarfs in binary systems. However, the identification of their progenitors, the evolutionary path leading to the explosion and the explosion mechanism itself have not been identified yet. This is critical, as we need to understand the potential evolution of their luminosity with cosmic time and, thus, with their stellar progenitors. We will review the current situation, considering observational hints. We will focus on our recent models, that follow the evolution of carbon-oxygen white dwarfs accreting mass up to thermonuclear runaway, and on their dependence with the initial metallicity of the white dwarf progenitors.
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Thivaharan, Yalini, and Indira Deepthi Gamage Kitulwatte. "Medico-Legal Opinion Based on Autopsy Findings of a Victim of an Explosion Involving Mass Fatality." Academic Forensic Pathology 10, no. 3-4 (December 2020): 158–65. http://dx.doi.org/10.1177/1925362120983669.
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Introduction: Investigation into explosions is one of the major areas in forensic medicine and pathology. Medico legal issues associated with these deaths are diverse and forensic experts are often expected to make clarifications. Assistance of a methodical scientific investigation of such a death in evaluation of unanswered medico legal issues, of an autopsy of one of the victims of Easter Sunday explosions is discussed. Case history: The deceased was a 15-year-old girl who was participating in the Easter mass at St. Sebastian’s Church - Kattuwapaitya, Negombo, Sri Lanka when a suicide bomber blew himself up. The mother of the deceased noticed the deceased being rushed to the hospital. However, she was pronounced dead on admission. Pre-autopsy radiology revealed spherical shrapnel in the temporal region. At autopsy, the fatal injury was found on the head and a detailed study revealed skull fractures associated with penetration by 3 shrapnels. There was a keyhole lesion among the penetrations. Internal examination revealed an extensive dural tear underlying the compound fracture. The brain was grossly edematous with lacerations on the frontal and parietal lobes associated with localized subarachnoid hemorrhage. There were multiple underlying contusions on bilateral frontal white matter. Small subarachnoid haemorrhage was noted on the basal aspect of the brain. Discussion: Careful evaluation of the autopsy findings assisted in formulating the opinion scientifically on event reconstruction including the proximity of the victim to the epicenter of explosion and nature of explosive device, period of survival, mechanism of causation of skull fractures and the mechanism of death in addition to the cause of death. Conclusion: A forensic pathologist following a meticulous autopsy examination, along with a team of ballistic experts and specially trained police personnel play a pivotal task in analyzing a scene of explosion and an autopsy of a victim, in concluding the case and in bringing justice to all the victims and survivors of the catastrophe.
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Gao, Rui, Bairong Wang, and Xia Luo. "Impact of explosive charge mass on reflected shock wave of high explosion." Journal of Physics: Conference Series 2010, no. 1 (September 1, 2021): 012086. http://dx.doi.org/10.1088/1742-6596/2010/1/012086.
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Cui, Yuanbo, Deren Kong, Jian Jiang, and Shang Gao. "Research on Electromagnetic Radiation Characteristics of Energetic Materials." Magnetochemistry 8, no. 5 (May 20, 2022): 57. http://dx.doi.org/10.3390/magnetochemistry8050057.
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During the explosion of energetic materials, electromagnetic interference is generated, which can affect the normal operation of surrounding electronic equipment. Therefore, an electromagnetic radiation measurement device based on a short-wave omnidirectional antenna and ultra-wideband omnidirectional antenna was designed to measure the electromagnetic radiation generated by the explosion of energetic materials of different masses, and the electromagnetic radiation characteristics were obtained through data processing. The results showed that the electromagnetic signal can still be collected hundreds of milliseconds after the explosive is detonated, and the electromagnetic radiation generated by the explosion is continuous and intermittent, which is a phenomenon that has not been found in this field at present. The mass of the energetic material had a significant effect on the time-domain characteristics of the electromagnetic radiation generated by the explosion: the higher the mass of the energetic material was, the shorter the delay response of the electromagnetic signal was, the longer the duration was, and the earlier the peak appeared. The frequency of electromagnetic radiation signals generated by the explosion of energetic materials was mainly concentrated below 100 MHz, and the energy was most concentrated in the frequency band of 0~50 MHz. The composition of energetic materials had the greatest influence on the spectral distribution, and the spectral distribution of electromagnetic radiation produced by the explosion of explosives with different compositions had obvious specificity. The electromagnetic radiation intensity generated by the explosion of energetic materials had a strong correlation with the distance from the explosion center, and it significantly decreased as the distance increased. The structure and detonation method of energetic materials changed the geometrical motion pattern during the explosion, resulting in the non-uniformity of electromagnetic radiation propagation.
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MOISEENKO, S. G., and G. S. BISNOVATYI-KOGAN. "OUTFLOWS FROM MAGNETOROTATIONAL SUPERNOVAE." International Journal of Modern Physics D 17, no. 09 (September 2008): 1411–17. http://dx.doi.org/10.1142/s021827180801298x.
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We discuss results of 2D simulations of magnetorotational (MR) mechanism of core collapse supernova explosions. Due to the nonuniform collapse, the collapsed core rotates differentially. In the presence of an initial poloidal magnetic field its toroidal component appears and grows with time. Increased magnetic pressure leads to the formation of a compression wave which moves outwards. It transforms into the fast MHD shock wave (supernova shock wave). The shape of the MR supernova explosion qualitatively depends on the configuration of the initial magnetic field. For a dipole-like initial magnetic field, the supernova explosion develops mainly along the rotational axis, forming a mildly collimated jet. A quadrupole-like initial magnetic field leads to the explosion developing mainly along the equatorial plane. The magnetorotational instability was found in our simulations. The supernova explosion energy grows with an increase of the initial core mass and rotational energy of the core, and corresponds to the observational data.
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THANG, Dam, Vladimir BELIN, and Tran DOANH. "STUDIES OF THE SHAPED CHARGES EFFECT WITH A HEMISPHERICAL ECCENTRIC SHAPE RECESS FOR THE ROCKS DESTRUCTION." Sustainable Development of Mountain Territories 13, no. 2 (June 30, 2021): 281–91. http://dx.doi.org/10.21177/1998-4502-2021-13-2-281-291.
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The method of outdoor installation of explosive charges is usually used in the destruction of rocks in conditions in which the method of drilling and blasting using borehole or borehole charges is difficult to apply due to objective conditions. The productivity of rock destruction by the outdoor installation of a concentrated charge is very low. This is due to the fact that such an explosion is characterized by a large loss of energy in the environment. The destruction of rocks by an explosion using shaped charges (CW) to destroy the rock is one solution to increase the useful energy of the destruction of the rock compared to charges placed outside. To achieve the optimal effect of destruction of the rock by cumulative charges, it is necessary to, so that for each type of rock, a specific type of shaped charges can be determined with the appropriate performance and efficiency of the use of explosives. The stronger the rock, the more efficient the short-circuit should be, and vice versa. Thus, for effective rock crushing, it is necessary to develop and produce a number of different types of shaped charges. The use of shaped explosive charges allows you to increase the utilization rate of the useful energy of the explosion and increase the destruction zone of the rock. At a fixed mass of the explosive, the destructive effect of the explosive charge placed on the surface of the rock, it depends on the shape of the charge and the geometric parameters of the charge. Shaped charges with an eccentric hemispherical shape have a coefficient of use of the useful energy of the explosion for the destruction of rock, more than 2.4 times compared to conventional concentrated charges of the same mass.
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Gilkis, Avishai, and Iair Arcavi. "How much hydrogen is in Type Ib and IIb supernova progenitors?" Monthly Notices of the Royal Astronomical Society 511, no. 1 (January 14, 2022): 691–712. http://dx.doi.org/10.1093/mnras/stac088.
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ABSTRACT Core-collapse supernovae showing little or no hydrogen (denoted by Type IIb and Ib, respectively) are the explosions of massive stars that have lost some or most of their outer envelopes. How they lose their mass is unclear, but it likely involves binary interaction. So far, seven progenitors of such supernovae have been identified in pre-explosion imaging (five for Type IIb events and two for Type Ib events). Here, we evolve detailed binary stellar evolution models in order to better understand the nature of these progenitors. We find that the amount of hydrogen left in the envelope at the time of explosion greatly depends on the post-interaction mass-loss rate. The leftover hydrogen, in turn, strongly affects progenitor properties, such as temperature and photospheric radius, in non-trivial ways. Together with extinction and distance uncertainties in progenitor data, it is difficult to deduce an accurate progenitor hydrogen mass from pre-explosion imaging. We quantify this uncertainty and find that available data are consistent with a proposed Type Ib–IIb hydrogen mass threshold of ${\approx}0.033\, \mathrm{M}_\odot$, implying that even Type Ib progenitors are not pure helium stars. These results alleviate the proposed tension between the Type Ib classification of SN 2019yvr and its candidate progenitor properties. We also estimate the brightness of a surviving 2019yvr progenitor companion, which might be detected in future observations.
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Pervikov, A. V., A. S. Lozhkomoev, O. V. Bakina, and M. I. Lerner. "Formation of phase composition of Ag-Cu bimetallic nanoparticles obtained by electrical explosion of wires." Izvestiya vysshikh uchebnykh zavedenii. Fizika, no. 9 (2020): 97–101. http://dx.doi.org/10.17223/00213411/63/9/97.
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In present work we observed structural phase state formation of Ag-Cu nanoparticles by electrical explosive of wires. We observed the formation of bimetallic nanoparticles with a number average size of 75 ... 82 nm by synchronous and nonsynchronous electric explosion of wires. The phase composition of the samples is represented by phases based on solid solutions of copper and silver. The results of the studies allow us to conclude that, using electric explosion of copper and silver wires, bimetallic Ag-Cu nanoparticles with different mass ratio of metals can be obtained.
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Boian, I., and J. H. Groh. "Catching a star before explosion: the luminous blue variable progenitor of SN 2015bh." Astronomy & Astrophysics 617 (September 2018): A115. http://dx.doi.org/10.1051/0004-6361/201731794.
Full textAbstract:
In this paper we analyse the pre-explosion spectrum of SN2015bh by performing radiative transfer simulations using the CMFGEN code. This object has attracted significant attention due to its remarkable similarity to SN2009ip in both its pre- and post-explosion behaviour. They seem to belong to a class of events for which the fate as a genuine core-collapse supernova or a non-terminal explosion is still under debate. Our CMFGEN models suggest that the progenitor of SN2015bh had an effective temperature between 8700 and 10 000 K, had a luminosity in the range ≃1.8−4.74 × 106 L⊙, contained at least 25% H in mass at the surface, and had half-solar Fe abundances. The results also show that the progenitor of SN2015bh generated an extended wind with a mass-loss rate of ≃6 × 10−4 to 1.5 × 10−3 M⊙ yr−1 and a velocity of 1000km s−1. We determined that the wind extended to at least 2.57 × 1014 cm and lasted for at least 30 days prior to the observations, releasing 5 × 10−5 M⊙ into the circumstellar medium. In analogy to 2009ip, we propose that this is the material that the explosive ejecta could interact at late epochs, perhaps producing observable signatures that can be probed with future observations. We conclude that the progenitor of SN2015bh was most likely a warm luminous blue variable of at least 35 M⊙ before the explosion. Considering the high wind velocity, we cannot exclude the possibility that the progenitor was a Wolf–Rayet (WR) star that inflated just before the 2013 eruption, similar to HD5980 during its 1994 episode. If the star survived, late-time spectroscopy may reveal either a similar luminous blue variable (LBV) or a WR star, depending on the mass of the H envelope before the explosion. If the star exploded as a genuine supernova (SN), 2015bh would be a remarkable case of a successful explosion after black hole formation in a star with a possible minimum mass 35 M⊙ at the pre-SN stage.