Explosive Type Research Articles

Mechanism and characteristics of thermal action of HMX explosive mixture containing high-efficiency fuel

In this study, the thermal stability and detonation properties of three types of explosives were investigated. Results indicated that nanoaluminum powder improved the detonation properties of HMX by increasing the specific surface area of HMX, which substantially increased the explosion heat and power. The decomposition temperatures of the three explosives containing aluminum hydride, ammonia borane, and nanoaluminum powder during slow cook-off at heating rates of 1.5 and 10°C min–1 were measured as 246°C and 241°C, 256°C and 261°C, and 238°C and 264°C, respectively. The explosives containing hydrogen storage materials swelled; however, the nanoaluminum powder was only slightly peeled off at the edge of the grains during cook-off. Differential scanning calorimetry (DSC) curves of the explosives containing hydrogen storage materials exhibited endothermic and exothermic peaks before the major exothermic reaction peak during the cook-off tests. In contrast, only one weak peak was observed in the DSC curve of the explosive containing nanoaluminum powder before the major exothermic reaction. In addition, the additives and adhesives catalyzed the slow cook-off decomposition, which caused the transformation of HMX crystals and accelerated the thermal decomposition reaction of HMX. The addition of high-density hydrogen storage materials to HMX resulted in detonation heats and explosion powers much greater than cure HMX. This improved performance was attributed to the hydrogen storage materials in the explosives participating in a secondary reaction in the reaction zone at the instant of the explosion, effectively realizing complementary lossless energy and thus greatly improving the explosive power of the explosives.

Development of Pyro-Drive Jet Injector With Controllable Jet Pressure

Various jet injectors have been developed and used for the effective and efficient administration of drugs. Jet injections overcome the limitations of other drug delivery methods, such as ablation, iontophoresis, electroporation, sonophoresis, and microneedles, because jet injection is not limited by the diffusion rates of different drugs. However, controlling the jet pressure during drug delivery is difficult with most conventional jet injectors. Efficacy evaluation of such devices on laboratory animals is strongly required before initiating human clinical trials, but minimal research has been performed for the device developments. Therefore, we developed jet injector devices based on pyrotechnics using 2 types of explosives with different burning rates; we call these pyro-drive jet injectors. The liquid jet pressure profile suggests that the penetration depth and injection volume for soft materials and skin tissue are controllable. Here, we propose the pyro-drive jet injectors as another candidate well-controlled jet injector for laboratory animals in drug discovery testing as well as human clinical use.

A special type of explosion of basin boundary

We study a special type of explosion of a basin boundary set in an archetypal oscillator. A typical feature is that the basin boundaries change the number of basins separating at the same time. Before the explosion, a basin boundary contains some Wada points of ten basins. After the explosion, the basin boundary contains some Wada points of eighteen basins. The underlying mechanism for the explosion is investigated by the heteroclinic tangency and Lambda lemma. Basin entropy and boundary basin entropy are also used to describe the nature of basins of attraction and the basin boundary explosion.

New methodical approaches to justify selection explosive for destruction of solid rocks

The article developed a mathematical model to justify selection the type of explosive for destruction of solid rocks. The problem is solved using the analytical hierarchy method (AHM). In the process, many criteria, both quantitative and qualitative, were considered, their importance in selecting the type of explosives and their consistency with the opinions of experts. The following indicators were used as criteria: technological, economic, social, environmental, etc. According to the results, priority vectors were obtained for each hierarchy, which contributed to a reasonable approach to selection type of explosives. The established priorities made it possible to carry out a systematic approach to solve the problem, considering not only technological advantages, but also the costs of using various types of explosives. The factors characterizing the costs in the formation of well charges with various types of explosives are also considered. The results of mathematical modeling showed the adequacy of chosen model for selection of alternative types of explosives for the destruction of solid rocks of complex structure.

Особенности в распределениях вторичных частиц во взаимодействиях ядер

The paper presents the results of an analysis of the interactions of heavy lead nuclei 208Pb at energy of 158 AGeV and gold nuclei 197Au at energy of 10.7 AGeV with photoemulsion nuclei Em. The results were processed using the Hurst method. The total ensemble of events has been divided into two classes dependending on the Hurst index h, which are called events of explosive and cascade-evaporation types. In explosive events, interactions have been discovered in which secondary particles are emitted at large angles. The analysis of this effect depending on the energy of the projectile nucleus is presented. Gold and lead nuclei have approximately the same mass, but they differ in energy by almost 15 times. However, the relative number of explosive events is almost the same. In the Au + Em interactions 64.7% of explosive events are observed. Moreover, 8.1% of the interactions are events of complete destruction which have no fragments of the target nucleus.  There are 59.7% of explosive type events and 8.9% of complete destruction events in Pb + Em interactions. However, the number of events with large values ​​of the mean pseudorapidity distribution <h> differs significantly. In Au + Em interactions, 35.6% of the events are explosive events with large <h> values. There are only 8.4% of such events in Pb + Em.

Element analysis method of concealed explosive based on TNA

The detection technology of concealed bulk explosives is related to social security and national defense construction and has important research significance. In this paper, an element analysis method of concealed explosives based on thermal neutron analysis is proposed. This method could provide better reconstruction precision for hydrogen, carbon, and nitrogen ratios, making it possible to discriminate explosives from other compounds with the same elements but different proportions, as well as to identify the types of concealed bulk explosives. In this paper, the basic principles and mathematical model of this method are first introduced, and the calculation formula of the element number ratio (the ratio between the nucleus numbers of two different elements) of the concealed explosive is deduced. Second, a numerical simulation platform of this method was established based on the Monte Carlo JMCT code. By calibrating the absorption efficiencies of the explosive device to γ rays, the element number ratios of a concealed explosive model under the irradiation of thermal neutrons were reconstructed from the neutron capture prompt γ-ray spectrum. The reconstruction values were in good agreement with the actual values, which shows that this method has a high reconstruction precision of the element number ratio for concealed explosives. Lastly, it was demonstrated using the simulation study that this method can discriminate explosives, drugs, and common materials, with the capability of determining the existence of concealed bulk explosives and identifying explosive types.

BLAST RESISTANT DESIGN PARAMETERS AGAINST AN UNCONTROLLED DEMOLITION (IMPLOSION) IN AUSTRALIA

Because of the uncertainty that presently exists within the Australian community of a possibleimprovised explosive device (IED) or vehicle improvised explosive device (VIED) detonating at some time inthe not too distant future there is uncertainty as to what would happen if an Australian engineer was approachedby a civilian developer to either design a new commercial structure or design a retrofit an existing commercialstructure what explosive charge weights are to be designed for and what type of explosives will be used? Withno Australian Standard or Design Code yet available the engineer could look for overseas examples for designparameters. Three events were considered in this paper using CONWEP software. A 5kg IED detonated on atop deck of a London bus with zero detonation distance amongst travelers generating a peak pressure of32.69MPa, a 1020kg VIED was detonated 3m from a club generating a peak pressure of 10.29MPa and amassive 2990kg VIED was detonated 6m from a multi-storey RC building generating a peak pressure of 5.83MPa. Peak pressures in all three events meant all were well above lethality for people and that destruction ofassets they were detonated in or next to was inevitable. As explosive charge weights can’t be controlled theonly parameter a designer can dictate is range. So, any design must be such that it forces a terrorist to detonateas far away from the intended target as possible thus reducing blast overpressures that impact people or assets.

Detection and Identification of the Traces of Explosives with Using of Active Spectral Imaging

AbstractAn optical‐electronic laser complex for the standoff detection of traces of explosives was developed with using of the Active Spectral Imaging. The tuning and automatization of the developed complex were performed. Experimental researches in detection of traces of various types of explosives on different substrates were carried out. On average, the probability of detection was 89 % and the probability of identification was 91 %.

Heavy sterile neutrinos in stellar core-collapse

We perform spherically symmetric simulations of the core collapse of a single progenitor star of zero age main sequence mass $M_{\rm ZAMS} = 15 \, M_{\odot}$ with two models of heavy sterile neutrinos in the mass range of hundred MeV$/c^2$. According to both models, these hypothetical particles are copiously produced in the center, stream outwards a subsequently decay releasing energy into final states (including neutrinos) of the Standard Model. We find that they can lead to a successful explosion in otherwise non-exploding progenitors. Depending on their unknown parameters (e.g., mass and coupling constants with matter), we obtain either no explosion or an explosion of one of two types, i.e., through heating of gas downstream of the stalled shock wave, similarly to the standard scenario for supernova explosions or through heating of gas at higher radii that ejects matter from the outer core or the envelope while the center continues to accrete matter. In both cases, the explosion energies can be very high. We presume that this new type of explosion would produce an electromagnetic signal that significantly differs from common events because of the relative absence of heavy elements in the ejecta. The combination of core-collapse simulations and astrophysical observations may further constrain the parameters of the sterile neutrinos.

Systematic study of magnetar-powered hydrogen-rich supernovae

Context. It has been suggested that some supernovae (SNe) may be powered by a magnetar formed at the moment of the explosion. While this scenario has mostly been applied to hydrogen-free events, it may also be possible for hydrogen-rich objects. Aims. We aim to explore the effect of including a magnetar on the light curves of supernovae with H-rich progenitors. Methods. We have applied a version of our one-dimensional local thermodynamic equilibrium radiation hydrodynamics code that takes into account the relativistic motion of the ejecta caused by the extra energy provided by the magnetar. For a fixed red supergiant (RSG) progenitor, we have obtained a set of light curves that corresponds to different values of the magnetar initial rotation energy and the spin-down timescale. The model is applied to SN 2004em and OGLE-2014-SN-073, two peculiar Type II SNe with long-rising SN 1987A-like light curves, although with much larger luminosities. Results. The presence of a plateau phase in either normal or superluminous supernovae is one possible outcome, even if a magnetar is continuously injecting energy into the ejecta. In other cases, the light curve shows a peak but not a plateau. Also, there are intermediate events with a first peak followed by a slow decline and a late break of the declining slope. Our models show that bright and long rising morphologies are possible even assuming RSG structures. Conclusions. A large number of supernova discoveries per year reveal unexpected new types of explosions. According to our results, SLSNe II-P are to be expected, as well as a variety of light curve morphologies that can all be possible signs of a newly born magnetar.

Rock Damage and Seismic Radiation: A Case Study of the Chemical Explosions in New Hampshire

Research Article| October 30, 2018 Rock Damage and Seismic Radiation: A Case Study of the Chemical Explosions in New Hampshire Anastasia Stroujkova Anastasia Stroujkova aWeston Geophysical Corp., 181 Bedford Street, Suite 1, Lexington, Massachusetts 02420, ana@westongeo.com Search for other works by this author on: GSW Google Scholar Bulletin of the Seismological Society of America (2018) 108 (6): 3598–3611. https://doi.org/10.1785/0120180117 Article history first online: 30 Oct 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Anastasia Stroujkova; Rock Damage and Seismic Radiation: A Case Study of the Chemical Explosions in New Hampshire. Bulletin of the Seismological Society of America 2018;; 108 (6): 3598–3611. doi: https://doi.org/10.1785/0120180117 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract The effect of the medium damage on seismic waves generated by underground chemical explosions in hard rock is investigated. An explosion experiment conducted in New Hampshire in 2016 has demonstrated that the amount of explosive gas products released in the cavity improves seismic coupling, which is manifested in higher seismic amplitudes. It has also shown that detonating explosions in water‐filled boreholes has similar effects on the spectra as increasing the amount of the gaseous detonation products by changing the explosive type. A postexplosion well logging survey revealed that using explosives releasing higher amount of gaseous products results in an increase in length and aperture of the explosion generated macrofractures. Placing the charges into water‐filled rather than drained boreholes results in a similar increase in fracture dimensions. Thus, the extent and intensity of postexplosion macrofracturing correlates with improved seismic coupling expressed as P and Rg amplitude increase, particularly in the low‐frequency range.The radiation patterns of the P waves are different for the waveforms bandpassed in a low‐frequency range (1–15 Hz) and a high‐frequency range (15–100 Hz). The symmetry of the radiation patterns indicates the presence of nonzero terms associated with the off‐diagonal moment tensor terms (⁠Mxz and Myz⁠). The amplitude of the seismic component attributed to the off‐diagonal moment tensor elements is significant and can be as large as 15%–16% of the isotropic moment. The observed P‐wave radiation pattern is consistent with either sliding along the pre‐existing fractures and zones of weakness or shear failure along the high‐angle borehole parallel fractures during the explosions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Do not believe the hype: Using case studies and experimental evidence to show why the HSE is wrong about excluding deflagration‐to‐detonation transitions

A recent report by the UK's Health and Safety Executive postulated that severe explosions can propagate at subsonic speeds but generate overpressures of several bar in open areas and this “new” type of explosion is episodic in nature. The UK Health and Safety Executive (HSE) paper based their findings on a specific interpretation of historical data and “empirical evidence” from previous incidents and selected experimental data. They indicate that their results should guide plant design and risk assessment. The report fails to take account of key evidence from recent large‐scale experimental studies and incident investigations in proposing a hypothetical explosion mechanism over those that are known to occur and are well understood. This has the potential to misdirect efforts to manage such events.The first part of the article will review a number of incidents and demonstrate that each of these incidents can indeed be explained by fast deflagrations or transition to detonations, in complete contradiction to the HSE findings. The results found at the incident sites will be directly compared against results from recent DDT work and damage. The second part of the paper will present a novel technique for determining the DDT transition velocity from high‐speed video footage of experiments performed at large scales. © 2018 American Institute of Chemical Engineers Process Saf Prog 38: e11998, 2019

Breathing and Coughing: The Extraordinarily High Degassing of Popocatépetl Volcano Investigated With an SO2 Camera

How do lava domes release volcanic gases? Studying this problem is crucial to understand, and potentially anticipate, the generation of the sudden and dangerous explosive eruptions that frequently accompany dome extrusions. Since its awakening in 1994, Popocatepetl volcano has produced more than fifty lava domes and has been consistently among the strongest permanent emitters of volcanic gases. In this work, we have characterized the passive and explosive degassing between 2013 and 2016 at a high time resolution using an SO2 camera, to achieve a better understanding of the conduit processes. Our 4-year average SO2 flux is 45 kg/s, in line with the long-term average of the whole current eruptive period. We show that Popocatepetl volcano is essentially an open system and that passive degassing, i.e. degassing with no associated emission of lava or ash, dominates >95% of the time. This passive degassing is continuous and sustained, whether the crater contains a lava dome or not. It shows most of the time a strong periodic component, with a pseudo-period of ~5 minutes, and amplitudes of 30 to 60% of the average value. We could distinguish two types of explosions based on their SO2 flux patterns. The first type (E1) occurs in the middle of the normal passive degassing and is followed by a rapid return of the SO2 flux down to its pre-explosive level. The second type (E2), which corresponds to the strongest events, is anticipated by a rapid decrease of the SO2 flux to abnormally low values and is followed by a return to its normal values. The E2 explosions are probably caused by the accumulation of gas below a rapidly compacting permeable dome. We suggest that transient episodes of gravitational compaction of the usually permeable dome and the upper conduit is the only mechanism that is fast enough to explain the sharp decrease of the SO2 flux that anticipates the E2 explosions. Our model is potentially applicable to a large number of andesitic volcanoes that undergo passive degassing interspersed with short-lived explosions.

Design of a Novel Linear Shaped Charge and Factors Influencing its Penetration Performance

In this paper, a novel linear shaped charge (LSC), called a bi-apex-angle linear shaped charge (BLSC), has been designed to investigate the improvement of penetration performance. Compared with a traditional single-apex-angle LSC, a BLSC, which consists of a small-apex-angle liner and a large-apex-angle liner, has been investigated by depth-of-penetration (DOP) test. The results show that the penetration depth of BLSC is 29.72% better than that of an ordinary LSC. An Eulerian method is applied to simulate the entire process of jet formation, as well as penetration on a #45 steel target. The effectiveness of the Eulerian model is demonstrated by the good agreement of the computational results with experimental observations. Furthermore, the numerical simulation is developed to investigate the influence of liner thickness, explosive type, combination of small and large apex angle, ratio of small to all apex angle liner, and standoff distance on the penetration performance of BLSCs. The suggested work and results can provide a guide and reference for the structural design of BLSC.

Investigation of Seismograms of North Korean Nuclear Explosion of September 3, 2017 Recorded by the Sakarya University and Kandilli Observatory Seismic Stations

A nuclear test was done on September 3, 2017 in North Korea. This activity is regarded as a nuclear test based on both CTBTO analysis and the statement of the official North Korean news agency. The type of explosion was announced as a fusion based thermonuclear hydrogen bomb. Preliminary solution of CTBTO International Data Center (IDC) reported the origin time, epicenter coordinates and magnitude as 03:30:01 UTC, 41.3°N 129.1°E, and Mb 6.1. U.S. Geological Survey (USGS) determined these parameters as 41.343°N, 129.036 °E and body wave magnitude, Mb 6.3.In this study the seismograms of September 3, 2017 North Korean nuclear test recorded by the Sakarya University and Kandilli Observatory seismic stations will be investigated.

The problem of determining the one‐dimensional matrix kernel of the system of viscoelasticity equations

The integro‐differential system of viscoelasticity equations with a source of explosive type is considered. It is assumed that the coefficients of the equations depend only on one spatial variable. The problem of determining the matrix kernel included in the integral terms of the equations is studied. The solution of the problem is reduced to a series of inverse problems for scalar hyperbolic equations. For each case, the inverse problem is replaced by an equivalent system of integral equations for unknown functions. The principle of constricted mapping in the space of continuous functions with weighted norms to the latter is applied. The theorems of global unique solvability are proved, and the stability estimates of solution to the inverse problems are obtained.

Investigation of relationships between soil type and condition and crater size for shallow-buried explosive charges

The detonation of near-surface and shallow-buried explosives results in a ground crater that has a size and shape that is directly related to the charge size, charge position, and soil conditions. Several methods are currently available that attempt to predict crater size, that is, apparent depth and diameter of a ground crater, based on direct inputs of key factors such as the soil type, soil conditions, explosive type and mass, and depth of burial of the explosive. Current prediction methodologies are limited, primarily due to the lack of key cratering data in well-controlled and characterized soil backfills consisting of a full range of soil types, water contents, and density conditions. A new cratering database is currently being developed based on craters produced in well-characterized materials representing a significant number of soil types defined by the Unified Soil Classification System. This database is capturing key cratering measurements for charge depth of burials ranging from tangent below the ground surface to a scaled depth of approximately 1.0 ft/lb1/3. Data collected include water content and density measurements in the as-constructed backfills and measurements of the crater cross-sectional profiles, including the apparent depth and diameter, lip-to-lip diameter, and lip-to-bottom depth. Analyses were conducted on the test data to define key parameters affecting crater size. Based on the results of these analyses, the critical soil parameters affecting crater size were identified.

Decoupled explosion in an underground opening and dynamic responses of surrounding rock masses and structures and induced ground motions: A FEM-DEM numerical study

Underground explosion during, e.g., blasting excavation, could generate shock waves, which propagate in surrounding rock mass and might result in damage or destruction of surrounding underground and ground structures. Therefore, it is significant to evaluate dynamic response and stability of underground and ground structures during underground explosion. We aim to understand the explosion process, to investigate blast-induced shock wave propagation in jointed rock mass and soil cover, and to determine the dynamic response of surrounding structures and ground motions, with the FEM-DEM method. Effects of explosive parameters including loading density, explosive type and explosion location, the shape of explosion chamber, joint parameters including joint stiffness, orientation, spacing and crossing angle, and soil cover thickness and ground locations on dynamic responses, wave attenuation and ground motions were investigated with the verified FEM based code AUTODYN and DEM based code UDEC. Results showed that peak particle velocity (PPV) increases with increasing charge loading density and decreasing scaled distance. PPV on side walls of the adjacent underground opening, in particular, on the side wall close to the explosion, increases with increasing charge loading density and decreasing distance from the explosion chamber. The explosive type, explosion location and explosion chamber shape have great effects on the PPVs of surrounding rock masses, dynamic responses of the adjacent opening and disturbed zone distributions. Joint properties could significantly influence blast-induced wave propagation. PPV increases with increasing joint stiffness or decreasing crossing angle between two joint sets. With increasing joint dip angle, PPV slightly decreases before sharply increasing. With increasing joint spacing, PPV increases before keeping constant. The ground soil cover could greatly attenuate blasting-induced wave, in particular when its thickness exceeded a critical value. The findings in this paper could be significant for blasting design, protective engineering and underground supporting.

A Passive Method for the Detection of Explosives and Weapons-Grade Plutonium in Nuclear Warheads

Before a nuclear warhead is dismantled, the special nuclear material and explosives must be identified and authenticated. This paper proposes a passive method to detect and identify weapons-grade plutonium cores and explosives in nuclear warheads based on neutron analyses techniques. This paper first describes the principles of a passive detection method that calculates the element number ratio (namely the ratio between the nucleus numbers of two different elements) of the element of interest to identify a source and how this method could be applied to the detection of warhead explosives. Second, a simulation of weapons-grade plutonium using JMCT software is described. The simulation assumes the elemental components of the explosives are activated by the production and transport of neutrons from the weapons-grade plutonium core and counted the gamma ray emissions of from the resultant hydrogen, carbon, and nitrogen nuclides with a high-purity germanium detector (HPGe) array. After an hour of counting, the element number ratios of these elements in the simulation were reconstructed and accurately matched the values for the explosives in the warhead. These results suggest that the passive method can be used to identify the presence of weapons-grade plutonium in the warhead. In addition, the simulation showed that the passive method can also discriminate between the various types of explosives in warheads, providing important physical information for the verification process during dismantlement.

Numerical Modeling of Wave Processes in Rocks by the Grid-Characteristic Method

The aim of this work is to study the spatial dynamic of wave propagation in rock formations, taking into account ravines and caverns. The dynamics of the seismic and acoustic waves generated by explosions of different types is investigated using seismograms measured by several reception lines. The research uses the numerical experiments using the full-wave joint simulation of acoustic and seismic wave propagation in heterogeneous mixed acoustic and linear-elastic media. The grid-characteristic method is used to obtain the mathematically and physically correct description of spatial dynamic wave processes taking the boundary and contact surfaces, including the interfaces between the linearelastic and the acoustic environments, into consideration. The influence of the type of explosion on the spatial dynamic wave patterns and seismograms is analyzed for the cases of horizontal and vertical reception lines. The dependences of spatial dynamic wave patterns and seismograms recorded by the horizontal and vertical reception lines on the distance of the karst caverns from the ravine are studied. The basic types of waves that different types of explosions generate in the rock formations, ravines, and caverns are investigated. The basic laws that characterize the emerging wave patterns and their influence on seismograms are found.