Explosives In Order Research Articles

A baseline approach for probabilistic blast risk analysis of building cladding under external explosions

The state of the practice in blast-resistant applications against explosions is to design the structural components for a prescribed combination of explosive mass and location, namely the design basis threat. In this context, the blast source is represented by specific scenarios, mostly associated with expert judgement, rating systems or code provisions. While offering a useful basis for practical applications, the level of detail can be significantly enhanced within a probabilistic framework for risk assessment. In research practice, plenty simplified probabilistic approaches have been proposed on external explosions in order to perform risk assessment. A rigorous methodology for such an assessment is presented herein, using tools and techniques derived from seismic risk-assessment applications. Specifically, the mean annual frequency of different explosive mass hazards is represented via a recurrence law, while the potential locations are modelled as a 2D spatial distribution, accounting for the various layers of defense that exist around the structure, i.e., perimeter protection, landscape, public or private spaces, etc. The methodology is finally substantiated with the case study of a typical building subjected to potential blast loadings from external aggressors.

Complex geometry of volcanic vents and asymmetric particle ejection: experimental insights

Explosive volcanic eruptions eject a gas-particle mixture into the atmosphere. The characteristics of this mixture in the near-vent region are a direct consequence of the underlying initial conditions at fragmentation and the geometry of the shallow plumbing system. Yet, it is not possible to observe directly the sub-surface parameters that drive such eruptions. Here, we use scaled shock-tube experiments mimicking volcanic explosions in order to elucidate the effects of a number of initial conditions. As volcanic vents can be expected to possess an irregular geometry, we utilise three vent designs, two “complex” vents and a vent with a “real” volcanic geometry. The defining geometry elements of the “complex” vents are a bilateral symmetry with a slanted top plane. The “real” geometry is based on a photogrammetric 3D model of an active volcanic vent with a steep and a diverging vent side. Particle size and density as well as experimental pressure are varied. Our results reveal a strong influence of the vent geometry, on both the direction and the magnitude of particle spreading and the velocity of particles. The overpressure at the vent herby controls the direction of the asymmetry of the gas-particle jet. These findings have implications for the distribution of volcanic ejecta and resulting areas at risk.

Technical solutions for the evaluation of the effect of explosion pressure when detoning various explosive loads in view of increasing the degree of societal security

The scientific article highlights the synthesis of the research results to assess the effect of explosive pressure on the detonation of various quantities of explosives in order to ensure a predictable level of societal security. The results of the experimental researches highlighted in the scientific papers were obtained following the tests with explosive materials performed on different specially configured experimental assemblies in order to analyze the propagation of the pressure wave on a mobile platform with specially configured pressure and gas sensors as well as on the explosion pressure measuring sensors within two modern Kistler systems. The visualization of air pressure waves for the experiments performed with these working montages was done by using a high-speed camera based on the BOS effect applied on fast video filming with adequate quality characteristics on the number of frames per second and the resolution obtained.

Działalność uznana za terrorystyczną w województwie pilskim w latach osiemdziesiątych XX wieku, w świetle sprawy obiektowej o kryptonimie „Przemoc”. Wybrane problemy

The object-related case, codenamed “Violence”, was conducted by the 3rd Department of the District Offi ce of Internal Aff airs in Piła during the years of 1984–1990. Its purpose was to identify, neutralize and eliminate acts bearing the hallmarks of terror, in particular; killings, beatings or deprivation of liberty for political reasons, explosions and arson of political objects and state institutions, collecting weapons and explosives in order to organize terrorist attacks, kidnapping people and planes, illegal political and nationalist organizations that use terror as a form of combat, as well as the operational control of channels to terrorist centres in capitalist countries.

Recent Advancements for the Recognization of Nitroaromatic Explosives Using Calixarene Based Fluorescent Probes.

In this era, explosives are easily available compared to the early days. Thus, more effective detection of explosives has become the main concern of homeland security. In the past decades, a large number of sensing materials have been developed for the detection of explosives in solid, vapor, and solution states through fluorescence methods. In recent years, great efforts have been devoted to developing new fluorescent materials with various sensing mechanisms for detecting explosives in order to achieve super-sensitivity, ultra-selectivity, as well as fast response time. Modified calixarenes have high potentials to detect nitroaromatic compounds (NACs) due to their favorable structural properties. It summarizes the detection of NACs by the modified calixarene system formed by the complex. Various methodologies responsible for complex formation and binding mechanisms (PET, FRET, EE, etc.) are the centerpiece of this review. Finally, conclusions and future outlook are presented and discussed.

Challenges and Strategies of Chemical Analysis of Drugs of Abuse and Explosives by Mass Spectrometry.

In analytical science, mass spectrometry (MS) is known as a “gold analytical tool” because of its unique character of providing the direct molecular structural information of the relevant analyte molecules. Therefore, MS technique has widely been used in all branches of chemistry along with in proteomics, metabolomics, genomics, lipidomics, environmental monitoring etc. Mass spectrometry-based methods are very much needed for fast and reliable detection and quantification of drugs of abuse and explosives in order to provide fingerprint information for criminal investigation as well as for public security and safety at public places, respectively. Most of the compounds exist as their neutral form in nature except proteins, peptides, nucleic acids that are in ionic forms intrinsically. In MS, ion source is the heart of the MS that is used for ionizing the electrically neutral molecules. Performance of MS in terms of sensitivity and selectivity depends mainly on the efficiency of the ionization source. Accordingly, much attention has been paid to develop efficient ion sources for a wide range of compounds. Unfortunately, none of the commercial ion sources can be used for ionization of different types of compounds. Moreover, in MS, analyte molecules must be released into the gaseous phase and then ionize by using a suitable ion source for detection/quantification. Under these circumstances, fabrication of new ambient ion source and ultrasonic cutter blade-based non-thermal and thermal desorption methods have been taken into account. In this paper, challenges and strategies of mass spectrometry analysis of the drugs of abuse and explosives through fabrication of ambient ionization sources and new desorption methods for non-volatile compounds have been described. We will focus the literature progress mostly in the last decade and present our views for the future study.

A DFT Treatment of Some Aluminized 1,3,3-Trinitroazetidine (TNAZ) Systems - A Deeper Look

1,3,3-Trinitroazetedine (TNAZ) is a powerful but insensitive energetic compound having C-NO2 and N-NO2 groups attached to a four-membered backbone. Aluminum powders are often added to explosives in order to have enhanced blast effect, etc. In the present study, aluminized TNAZ system is modeled for 1-3 Al atom(s) per TNAZ molecule within the restriction of density functional theory at the levels of UB3LYP/6-311++G(d,p) and UB3LYP/cc-PVDZ. Certain structural, physical and quantum chemical properties are obtained and discussed. The considered properties are found to be highly dependent on the multiplicity (thus the number of Al atoms present) of the composite systems considered. Also, calculated IR and UV-VIS spectra of the composites have been presented.

Fuel characteristics and explosiveness analysis of pulverized coal industrial boilers in China

Pulverized coal industrial boilers are widely used in China in recent years for high thermal efficiency and suitable for contract energy management, especially the in service amount is growing fast in regions like Shanxi, Gansu, Shandong, Tianjin, Liaoning, Hebei, etc. Considering the existing operational safety issues of pulverized coal fired industrial boiler, this article researched the relationship between fuel characteristics including calorific value, volatile, ash, moisture and powder explosion in order to explore and analysis in service pulverized coal industrial boilers explosiveness.

Effects of dry explosion pretreatment on physicochemical and fuel properties of hybrid pennisetum (Pennisetum americanum × P. purpureum)

Pretreatment of lignocellulose is a critical step in biomass exploitation. This paper proposed a dry explosion pretreatment based on steam explosion in order to improve energy efficiency and treatment effects. A laboratory simulation test bench was built. Hybrid pennisetum was selected as the experimental material. Dry explosion pretreatment under different conditions (temperature: 200, 225, 250, 275 °C, time: 10, 20 min) was conducted. The results showed that dry explosion had lower energy consumption level than steam explosion. Moreover, dry explosion enhanced fuel properties of biomass. The crystallinity of treated samples decreased greatly at high treatment severity. Multiple pyrolysis properties of samples increased first and then decreased with the increase of treatment severity, which was mainly due to dry explosion changing the proportion and nature of the components. These results showed that dry explosion pretreatment can effectively convert biomass into intermediate materials that are beneficial for thermochemical applications.

Investigating the Efficiency of Explosion Chemistry as a Source of Complex Organic Molecules in TMC-1

Abstract Many species of complex organic molecules (COMs) have been observed in several astrophysical environments but it is not clear how they are produced, particularly in cold, quiescent regions. One process that has been proposed as a means to enhance the chemical complexity of the gas phase in such regions is the explosion of the ice mantles of dust grains. In this process, a build up of chemical energy in the ice is released, sublimating the ices and producing a short lived phase of high density, high temperature gas. The gas–grain chemical code UCLCHEM has been modified to treat these explosions in order to model the observed abundances of COMs toward the TMC-1 region. It is found that, based on our current understanding of the explosion mechanism and chemical pathways, the inclusion of explosions in chemical models is not warranted at this time. Explosions are not shown to improve the model’s match to the observed abundances of simple species in TMC-1. Further, neither the inclusion of surface diffusion chemistry, nor explosions, results in the production of COMs with observationally inferred abundances.

Blankenship, Robert Suicide in East German Literature: Fiction, Rhetoric, and the Self-Destruction of Literary Heritage (review)

SEER, 96, 4, OCTOBER 2018 768 All of this was and continues to be a very thorny puzzle, indeed, and one can only wonder at the hidden irony pervading these events when an author’s free voice from a hermetically sealed society is assisted by a secret organization, with all its cloak and dagger modes of operation, while so many liberal-minded socialists, fighting for the liberation of the world, in their attempt to placate the Soviet Communist party, were intent on suppressing the novel’s publication. To clarify this unlikely scenario, Mancuso seeks to discover which of the six manuscripts that travelled to the West was used by the CIA, a question that leads to yet another mystery: the identity of the person, who, among the anxious guardians of the novel’s copies, agreed to give the manuscript to the CIA. In this perilous quest, Mancosu stays the course, and while not every question is answered, the overall chain of events is presented with a sure touch. Mancosu does this by collecting the very diverse material into eighteen chapters, each with a new protagonist. One of the early chapters is also devoted to the Soviet suppression of the Hungarian revolt in November 1956, which stunned the world on both sides of the Iron Curtain, undermined Feltrinelli’s allegiance to the Russian version of Communism, and emphasized the depth of danger faced by Pasternak. We also see the heavily redacted report of the CIA, explaining the process that led to their publication of the novel. And we also have a very useful Appendix that presents all the relevant correspondence, followed by a helpful index. Mancosu notes in passing that ‘Pasternak had sent Doctor Zhivago abroad hoping to pressure the Soviets to publish the novel at home’ (p. 113). This is the only conclusion I would question, for it is more probable that Pasternak realized very quickly, or even sensed this at the very beginning, that the explosive spirit of his work would never pass the censorship of a one-party system country. Apart from this, one cannot but admire the precision, scope and clarity of Mancosu’s exposition of this startling literary event of the twentieth century. Emory University Elena Glazov-Corrigan Blankenship, Robert. Suicide in East German Literature: Fiction, Rhetoric, and the Self-Destruction of Literary Heritage. Studies in German Literature, Linguistics, and Culture. Camden House, Rochester, NY. 2017. vii + 193 pp. Notes. Bibliography. Index. $90.00: £75.00. In this intellectually stimulating book, literary scholar Robert Blankenship imaginatively explores the narrative strategies of GDR authors dealing with self-destruction. Blankenship places special emphasis on intertextuality, subtly analysing how East German authors reworked classic texts to reveal REVIEWS 769 their complex literariness. Blankenship discusses the various ways in which East German writers, such as Ulrich Plenzdorf, Christa Wolf, Heiner Müller, Christoph Hein and Werner Heiduczek, transposed classical stories (among them, Shakespeare’s Hamlet, Goethe’s Werther and Kleist’s Penthesilea) from their original settings into the 1970s behind the Iron Curtain and, most notably, how these appropriations exposed the subversive dynamics within the restrictive cultural climate of the GDR. ScholarswhoconstruesuicideinGDRliteraturemainlyasrealisticdepictions of individual self-destruction see its subversive potential as deriving merely from the fact that these writings break a taboo, highlighting the repression and despair of life under Communist dictatorship. By contrast, Blankenship argues that it is its ‘rich literariness’ which makes East German literature on suicide ‘so subversive’ (p. 27). Seeking for the mechanisms at work in both novels and plays, he shows how East German authors used suicide as a metaphor and how they produced aesthetic effects such as transgression, fluidity, or even explosion in order to instigate counter-memory. Consequently, this study does not pay much attention to the problems of individual suicide, so that the fatal victim of this study is less the individual but more the literary canon of the GDR. Such an understanding of suicide cuts both ways. In places, it tempts the author to overstatement. Blankenship goes so far as to assert that official literary heritage guarded by cultural authorities ‘was itself suicidal’ (p. 139). This application of suicide as a metaphor to denote ‘the self-destructiveness inherent in any programmatic...

The effect of explosive percentage on underwater explosion energy release of hexanitrohexaazaisowurtzitane and octogen based aluminized explosives

To control the explosion energy output by optimizing explosive components is a key requirement in a number of different application areas. The effect of different Al/O Ratio on underwater explosion of aluminized explosives has been studied detailedly. However, the effect of explosive percentage in the same Al/O Ratio is rarely researched, especially for Hexanitrohexaazaisowurtzitane (CL-20) based aluminized explosives. In this study, we performed the underwater explosion experiments with 1.2-kilogram explosives in order to investigate the explosion energy released from CL-20 and Octogen (HMX) based aluminized explosives. The percentage of the explosive varied from 5% to 30% and it is shown that: the shockwave peak pressure (pm) grows gradually; shock wave energy (Es) continues increasing, bubble energy (Eb) increases then decreases peaking at 15% for both formulas, and the total energy (E) and energy release rate (η) peak at 20% for CL-20 and 15% for HMX. This paper outlines the physical mechanism of Eb change under the influence of an aluminium initial reaction temperature and reaction active detonation product percentage coupling. The result shows that CL-20 is superior as a new high explosive and has promising application prospects in the regulation of explosive energy output for underwater explosives.

Assessment of pre‐treatment technologies for bioethanol production from sugarcane bagasse considering economics and environmental impact

AbstractThis work involves the assessment of various pre‐treatment methods for the production of bioethanol in South Africa from sugarcane bagasse. The possibility of producing methane was also considered. The pre‐treatment methods that have been modelled are acid pre‐hydrolysis, steam explosion (acid‐catalysed and un‐catalysed), delignification with sodium hydroxide, acid hydrolysis and enzymatic hydrolysis. These pre‐treatment options were arranged in a superstructure, and optimization was performed by decomposing the superstructure into eight possible flowsheets. These flowsheets were then optimized in General Algebraic Modelling Systems by using economic and environmental objective functions sequentially. The solution space was used to evaluate the possible flowsheets in terms of both objectives. Steam explosion pre‐treatment would be recommended for the production of only methane. Acid hydrolysis can be added to steam explosion in order to produce glucose (for bioethanol production), and this increases profitability and reduces environmental impact of the steam explosion only flowsheet; however, the glucose flowrate from the steam explosion with acid hydrolysis flowsheet is low. The steam explosion with enzymatic hydrolysis flowsheet would be recommended to produce a higher glucose flowrate; however, the environmental impact of this flowsheet may be large if the electricity consumption of enzyme production is large. Copyright © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.

PR PHANTOM OF THE SYRIAN OPPOSITION

PR PHANTOM OF THE SYRIAN OPPOSITION

Constraining SN feedback: a tug of war between reionization and the Milky Way satellites

Theoretical models of galaxy formation based on the cold dark matter cosmogony typically require strong feedback from supernova (SN) explosions in order to reproduce the Milky Way satellite galaxy luminosity function and the faint end of the field galaxy luminosity function. However, too strong a SN feedback also leads to the universe reionizing too late, and the metallicities of Milky Way satellites being too low. The combination of these four observations therefore places tight constraints on SN feedback. We investigate these constraints using the semi-analytical galaxy formation model galform. We find that these observations favour a SN feedback model in which the feedback strength evolves with redshift. We find that, for our best fit model, half of the ionizing photons are emitted by galaxies with rest-frame far-UV absolute magnitudes $M_{\rm AB}(1500{\rm \AA})<-17.5$, which implies that already observed galaxy populations contribute about half of the photons responsible for reionization. The $z=0$ descendants of these galaxies are mainly galaxies with stellar mass $M_*>10^{10}\,{\rm M}_{\odot}$ and preferentially inhabit halos with mass $M_{\rm halo}>10^{13}\,{\rm M}_{\odot}$.

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

Small scale characterization experiments using only 1–5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, it is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.

Microstructure and Mechanical Properties After Shock Wave Loading of Cast CrMnNi TRIP Steel

The mechanical response of shock wave-prestrained high-alloy Cr16-Mn7-Ni6 TRIP steel was investigated under compressive and tensile loading at room temperature. Previous shock wave loading was carried out using a flyer-plate assembly with different amounts of explosives in order to achieve shock pressures of 0.3, 0.6, 0.9, and 1.2 Mbar. A significant increase in hardness and strength was observed as compared with the initial as-cast condition. In contrast, a slight decrease in strain hardening rates was measured together with a decrease in fracture elongation in the tensile test. Microstructural analyses of the shock-loaded samples were performed by light optical and scanning electron microscopy. The microstructure revealed a high density of deformation bands consisting of separated stacking faults, e-martensite, or twins. Significant amounts of deformation-induced α′-martensite were only present at the highest shock pressure of 1.2 Mbar. The thickness of the deformation bands and the number of martensite nuclei at their intersections increased with increasing shock pressure. In all shock-loaded specimens, pronounced phase transformation occurred during subsequent mechanical testing. Consequently, the amount of the deformation-induced α′-martensite in the shock-loaded specimens was higher than in the unshocked as-cast samples.

Maximum overpressure vs. H2 concentration non-monotonic behavior in vented deflagration. Experimental results

Explosion relief panels or doors are often used in industrial buildings to reduce damages caused by gas explosions. Decades of research have contributed to the understanding of the phenomena involved in gas explosions in order to establish an effective method to predict reliably the explosion overpressure. All the methods predict a monotonic increase of the overpressure with the concentration of the gas in the range from the lower explosion limit to the stoichiometric one. Nevertheless, in few cases, a non-monotonic behaviour of the maximum developed pressure as a function of hydrogen concentration was reported in the literature. The non-monotonic behaviour was also observed during experimental tests performed at the Scalbatraio laboratory at the University of Pisa, in a 25 m3 vented combustion test facility, with a vent area of 1,12 m2. This paper presents the results obtained during the tests and investigates the possible explanations of the phenomena.

Modelling Multi-Input-Single-Output (MISO) Production Process Using Transfer Function: A Case Study of a Brewery

Material requirement planning in production systems usually require product explosion in order to determine the raw materials required to produce a given quantity of product in a given horizon. Product explosion can easily be done in cases when the product is a discrete item but becomes impossible in flow production processes. In this situation an appropriate method of relating input to output of processes, such as transfer function, would be used as an alternative to product explosion in material requirement planning. In this study, transfer function is used to model the relationship between the input and output of a brewery. It involved taking the inputs and outputs to the brewery for three different periods and determining the transfer functions. The determined transfer functions were compared with an equivalent model obtained using regression analysis. The results show that transfer function models performed better than regression analysis. In addition the raw materials quality variability and product variability, a key characteristics of the process industry, was effectively modeled. Transfer function is therefore recommended as the preferred tool for material requirement planning for breweries.

Comprehensive Infrared Study of Tetryl, Dinitrotoluene, and Trinitrotoluene Compounds.

The present work describes an experimental and theoretical study of energetic materials used for detecting explosives in order to prevent terrorist actions, as well as for de-mining projects. Particular attention was devoted to examining the infrared absorption spectroscopy of classic explosives in order to create a useful mobile apparatus for on-field detection of explosives. This paper reports the vibrational absorption spectra of tetryl, dinitrotoluene, and trinitrotoluene molecules approached using two different spectroscopic techniques, Fourier transform infrared spectroscopy (FT-IR) and laser photoacoustic spectroscopy (LPAS). Diffuse reflectance Fourier transform infrared spectra of all samples were analyzed in a very wide spectral range (400-7500 cm(-1)) showing for the first time the existence of weak absorption bands attributable to overtones or combination bands, while laser photoacoustic spectroscopy spectra have been investigated in the fingerprint region of organic compounds that share the CO2 laser emission range (~920-1100 cm(-1)). The Fourier transform infrared spectra of both matrix isolated dinitrotoluenes have been also investigated. The theoretical treatment of tetryl is reported for the first time.