Academic literature on the topic 'Explosion Phenomenon'
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Journal articles on the topic "Explosion Phenomenon"
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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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Mubarok, Muhammad Arif Husni, Aditya Rio Prabowo, Teguh Muttaqie, and Nurul Muhayat. "Dynamic Structural Assessment of Blast Wall Designs on Military-Based Vehicle Using Explicit Finite Element Approach." Mathematical Problems in Engineering 2022 (September 13, 2022): 1–22. http://dx.doi.org/10.1155/2022/5883404.
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Explosion load studies are an essential part of shield engineering design. This is especially true for explosion-proof plates, which are used in order to reduce the impact of explosions, which have the potential to cause substantial damage to structural elements. The purpose of this study is to detail the explosion phenomenon and the response of sandwich panel structures under explosive loading. The finite element method (FEM) is used to model the dynamic structural response to explosions. Explicit finite element modeling and analysis are performed using ABAQUS CAE software. An air explosion simulation code is used to determine the blast load on the lower skin plate of a test panel on a typical armored personnel vehicle. Structural analysis is carried out with respect to displacement, von-Mises stress, and internal kinetic energy. Three variations of explosive loads are considered in the simulation in order to better compare the responses of the structures. Three different design variants and materials are considered, including honeycomb, stiffener, and corrugated geometric models and mild steel, medium carbon steel, and alloy steel materials. The results provided by this study pave the way toward the development of guidelines for the design of lightweight structural reinforcement elements.
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Li, Dong, Shijie Dai, and Hongwei Zheng. "Investigation of the explosion characteristics of ethylene-air premixed gas in flameproof enclosures by using numerical simulations." Thermal Science, no. 00 (2022): 189. http://dx.doi.org/10.2298/tsci220905189l.
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Flameproof enclosures are widely installed as safety equipment at dangerous industrial sites to reduce ignition risks. However, electrical components typically installed in such flameproof enclosures for the production process can cause ignition and compromise the safety of the enclosures. Thus, in such cases, the explosive characteristics of the flameproof enclosures is severely affected. Accidental gas explosions in industrial sites rarely occur under standard operating conditions. Premixed gas explosions in flameproof shells are complex processes. A 560 mm ? 400 mm ? 280 mm flameproof enclosure commonly used in industrial sites was used to investigate the phenomenon. The explosion characteristics of ethylene-air premixed gas in the flameproof enclosure was simulated using Fluent software to investigate the influences of ignition source location, ignition source energy, ambient temperature, and obstacles on the maximum explosion pressure, maximum explosion pressure rise rate, and maximum explosion index of the flameproof enclosure. The results revealed that the surface area of heat exchange considerably influences the maximum explosion pressure of the flameproof enclosure. The larger the ignition energy is, the larger the maximum explosion pressure value, the maximum rate of explosion pressure rise, and the maximum explosion index of the flameproof enclosure are. With the increase in the ambient temperature, the maximum explosion pressure decreased, whereas the maximum rate of explosion pressure rise and the maximum explosion index exhibited limited change. The results of this study provide theoretical guidance for the design and suppression of flameproof enclosures.
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Hirai, Eiko, Joho Tokumine, Alan Kawarai Lefor, Shinobu Ogura, and Miwako Kawamata. "Bladder Explosion during Transurethral Resection of the Prostate with Nitrous Oxide Inhalation." Case Reports in Anesthesiology 2015 (2015): 1–3. http://dx.doi.org/10.1155/2015/464562.
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Bladder explosions are a rare complication of transurethral resection of the prostate. We report a patient who suffered a bladder rupture following transurethral resection of the prostate. Although explosive gases accumulate during the procedure, a high concentration of oxygen is needed to support an explosion. This rare phenomenon can be prevented by preventing the flow of room air into the bladder during the procedure to maintain a low concentration of oxygen inside the bladder.
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Antonov, Dmitrii V., Roman M. Fedorenko, and Pavel A. Strizhak. "Micro-Explosion Phenomenon: Conditions and Benefits." Energies 15, no. 20 (October 18, 2022): 7670. http://dx.doi.org/10.3390/en15207670.
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Adding water to fuel droplets is known to lead to puffing and micro-explosion. Puffing and micro-explosion lead to a rapid increase in the liquid fuel surface area. This, in turn, leads to an increase in the fuel evaporation rate and the formation of a homogeneous fuel vapor/air mixture. The latter is important for improving the efficiency of combustion technologies, including those used in internal combustion engines. The effects produced by puffing and micro-explosion lead to a reduction in fuel consumption, improved fuel/air mixing, and a reduction in harmful emissions. The contributions of puffing and micro-explosion to fire extinguishing have also been discussed in many papers. In this paper, we review the state of the art in the investigation of composite droplet micro-explosion and discuss the sufficient conditions for the start of puffing/micro-explosion as well as child droplet characteristics.
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Ogunfuye, Samuel, Hayri Sezer, Furkan Kodakoglu, Hamed Farmahini Farahani, Ali S. Rangwala, and V’yacheslav Akkerman. "Dynamics of Explosions in Cylindrical Vented Enclosures: Validation of a Computational Model by Experiments." Fire 4, no. 1 (February 15, 2021): 9. http://dx.doi.org/10.3390/fire4010009.
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Recent explosions with devastating consequences have re-emphasized the relevance of fire safety and explosion research. From earlier works, the severity of the explosion has been said to depend on various factors such as the ignition location, type of a combustible mixture, enclosure configuration, and equivalence ratio. Explosion venting has been proposed as a safety measure in curbing explosion impact, and the design of safety vent requires a deep understanding of the explosion phenomenon. To address this, the Explosion Venting Analyzer (EVA)—a mathematical model predicting the maximum overpressure and characterizing the explosion in an enclosure—has been recently developed and coded (Process Saf. Environ. Prot. 99 (2016) 167). The present work is devoted to methane explosions because the natural gas—a common fossil fuel used for various domestic, commercial, and industrial purposes—has methane as its major constituent. Specifically, the dynamics of methane-air explosion in vented cylindrical enclosures is scrutinized, computationally and experimentally, such that the accuracy of the EVA predictions is validated by the experiments, with the Cantera package integrated into the EVA to identify the flame speeds. The EVA results for the rear-ignited vented methane-air explosion show good agreement with the experimental results.
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Menčík, Matej, Richard Kuracina, Zuzana Szabová, and Karol Balog. "Determination of Fire and Explosion Characteristics of Dust." TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series 11, no. 2 (September 1, 2016): 36–42. http://dx.doi.org/10.1515/tvsbses-2016-0015.
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Abstract The aim of this paper is to approximate danger of dust clouds normally occur by determining their explosion characteristics. Nowadays, dusty environment is phenomenon in the industry. In general, about 70% of dust produced is explosive. Dust reduction in companies is the main purpose of the national and European legislative. Early identification and characterization of dust in companies may reduce the risk of explosion. It could be used to identify hazards in industrial production where an explosive dust is produced. For this purpose several standards for identification and characterization of explosion characteristics of industrial dust are being used.
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Stump, Brian W. "Constraints on explosive sources with spall from near-source waveforms." Bulletin of the Seismological Society of America 75, no. 2 (April 1, 1985): 361–77. http://dx.doi.org/10.1785/bssa0750020361.
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Abstract Spall, the tensile failure of a material due to high stress loading, has been observed in a number of contained and surface explosions. The phenomenon results in a repartition of the initial spherical explosion energy source, yielding a second energy source which is cylindrical and delayed in time. Recent spall models by Day et al. (1983) demanding conservation of momentum have shown the phenomenon to have little contribution to 20-sec surface waves. These models are extended to include the effect of the process on near-source seismograms. The spall model is constrained by observations within the nonlinear regime of the source which bound the mass, momentum, and timing of the process. Comparison of these forward models with the inverse vertical point force source inferred from seismic recordings of a bermed surface explosion yields excellent agreement. The spall model developed from the contained explosion, CHEAT, is used to create synthetic seismograms. Comparisons of these waveforms with those from a Mueller-Murphy contained explosion indicate that the waveform contribution from spall is similar in size to the spherical explosion waveform. The complete synthetic composed of the spall and explosion contribution compares favorably with observational data from the CHEAT experiment in both amplitude and energy distribution.
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Xiong, Ziming, Qinghua Zhang, Hao Lu, Shaoshuai Shi, Zewei You, Yuanpu Xia, and Lin Bu. "Evaluation and identification of dynamic strain on a blast door subjected to blast loading using fibre Bragg grating sensors." International Journal of Distributed Sensor Networks 14, no. 3 (March 2018): 155014771876686. http://dx.doi.org/10.1177/1550147718766860.
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Tunnels and subway blast doors are effective barriers to terrorist attacks and emergencies, and research into the mechanical properties of blast doors under explosive dynamic loads can improve and enhance the performance thereof. In this article, surface strain measurements on subway blast door models under dynamic load are carried out using quasi-distributed fibre Bragg grating sensors. The principle underpinning fibre Bragg grating sensing is introduced before the experiment. In the experiment, a model of an explosion-proof door was designed, and the experimental foundation pit was designed to be used to fix the explosion-proof door. Then, eight fibre Bragg grating sensors are placed at different positions on the surface of the explosion door to measure the strain at the time of explosion. Through the experiment we found that the optical fibre grating sensing system can be used under explosive loading surface strain: the strain distribution on the surface of the protective door is revealed under large dynamic strain. At the same time, the rebound effect of the protective door in the explosion was found through the strain phenomenon in double peak phenomenon. The strain distribution and rebound effect in the test results can provide a useful reference for the mechanical design of the blasting door and the strain monitoring of reinforced concrete structures under dynamic load.
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Sun, Wen Bin, Yang Jiang, and Wei Zhong He. "An Overview on the Blast Loading and Blast Effects on the RC Structures." Applied Mechanics and Materials 94-96 (September 2011): 77–80. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.77.
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An explosion is defined as a large-scale, rapid and sudden release of energy. Explosions, such as a bomb explosion within or immediately nearby a building and a gas-chemical explosion, can cause catastrophic damage on the building's frames, collapsing of walls, blowing out of large expanses of windows, and shutting down of critical life-safety systems. In fact, an explosion may result in large dynamic loads, greater than the original design loads, of many structures. Blast phenomenon and blast efforts have been made during the past several decades to develop methods of structural analysis and design to resist blast loads. The analysis and design of structures subjected to blast loads require a detailed understanding of blast phenomena and the dynamic response of various structural elements. This paper introduces different methods to estimate blast loads, also presents a comprehensive overview of the effects of explosion on RC structures.
Dissertations / Theses on the topic "Explosion Phenomenon"
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Duong, Giao ky. "Formation de singularités en temps fini pour les équations aux dérivées partielles non symétriques ou non variationnelles." Thesis, Sorbonne Paris Cité, 2019. http://www.theses.fr/2019USPCD058.
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Dans le cadre de cette thèse, nous nous intéresserons à la formation de singularités en temps fini pour les équations d’´évolution de type parabolique. En particulier, nous nous concentrons sur l’´étude des deux phénomènes principaux suivants : l’explosion et l’extinction en temps fini. Dans cette thèse, nous considérons les équations suivantes : [....] où Ω est un domaine borné de classe C² dans ℝᶰ et λ, Ƴ sont positifs.Ces modèles se rapportent `a plusieurs phénomènes naturels. En particulier, l’équation(3) modélise un système micro ´electro-mécanique (MEMS).Dans ce travail, nous avons construit des solutions explosives (pour (1) et des (2)) et des solutions avec extinction pour (3). En plus de ¸ça, nous décrivons le comportement asymptotique des solutions autour du point singulier.Comme cadre pour notre travail, nous utilisions celui des variables auto-similaires qui a ´et´e introduit par Giga et Kohn dans CPAM 1985. Nous obtenons les résultats en utilisant une réduction en dimension finie du problème et un argument topologique qui a´et´e notamment introduit par Bressan, Bricmont et Kupiainen ainsi que par Merle et Zaag. Clairement, notre travail n’est pas une simple adaptation des travaux cit´es ci-haut.En effet, nos modèles, par leur proximité avec les applications, sortent du cadre idéal considéré dans les travaux pionniers. En particulier, l’équation (1) n’est pas invariante par changement d’échelle, alors que (2) n’admet pas de structure variationnelle. Quant à (3), la présence du terme intégral (donc non-local) nous oblige `a une manipulation plus délicate.En fait, nous avons atteint nos objectifs grˆace `a quelques nouvelles idées. Plus précisément,pour (2), nous effectuons un contrôle délicat de la solution afin qu’elle reste dans un domaine où la non linéarité est définie sans ambiguïté. Pour (3), nous contrôlons l’oscillation du terme non-local afin qu’il reste assez petit et nous en déduisons sa convergenceIn the context of this thesis, we are interested in finite time singularity formation for non symmetric or non variational partial differential equations of parabolic type. In particular, we mainly focus on the following two phenomena : blowup and quenching (touch-down) infinite time. In this thesis, we aim at studying the following equations : [....] where Ω is a C² bounded domain in ℝᶰ and λ, Ƴ are positive constants.These models are closely related to many common phenomena in nature. In particular, equation (6) is a model for Micro Electro Mechanical Systems (MEMS). In this work, we construct blowup solutions to (4) and (5) and solutions with extinction to (6). In addition to that, we describe the asymptotic behavior of these solutions around the singular point. We use in this thesis the framework of similarity variables, introduced by Giga and Kohn in CPAM 1985. We finally derive the results by using a reduction to a finite dimensional problem and a topological argument which was introduced in particular by Bressan, Bricmont and Kupiainen, and also Merle and Zaag. Clearly, our work is not a simple adaptation of the works cited above. Indeed, our models, by their proximity to applications, are outside the ideal framework considered in pioneering works. In particular, equation (4) is not scaling-invariant, whereas (5) does not admit variational structure. As for (6), the presence of the integral term (non-local term) requires us to treat this term more delicately. In fact, we have achieved our goals thanks to some new ideas. More precisely, for (5), we carry out a delicate control of the solution so that it always stays in the domain where the non linearity is defined with no ambiguity. For (6), we control the oscillation of the non-local term to keep it small enough, and this allows us to deduce its convergence
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Roser, Markus. "Investigation of dust explosion phenomena in interconnected process vessels." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/11692.
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It is well known that where-ever combustible dusts are handled, or result as a waste product, unwanted ignitions and explosions can occur. Dust explosions present a high potential risk in the process industries. The past has shown that, in the European Union, more than 2,000 dust / air or gas / air explosions occur each year. In Germany alone the damage of dust explosions costs more than £ 16,000 per day. A lot of fundamental research work on dust explosion has been done for single vessels however, in reality, vessels are normally connected via pipes to other process vessels. To prevent secondary vessel explosions, and to protect interconnected vessels from the effects of explosions, further research into these complex phenomena is required. This research work concerns the investigation of dust explosion phenomena in interconnected vessels. Large scale tests were conducted in which I m' or 4.25 m' process vessels were connected via a pipe to a realistically filled 9.4 m' vessel. Pressure transducers were placed in the vessels and along the pipe, also photo diodes, positioned along the pipe, were used to measure the pressure development and the flame front velocity respectively. In further investigations the process vessels were connected to an open ended pipe. It was possible to estimate, with the aid of a CCD camera, the flame shape and flame length of the emerging flame jet dependent on the explosion course at the process vessel. The results have shown that, under different circumstances, dust explosion propagation from the primary process vessel through the connecting pipe which reaches the secondary silo as a flame jet, may ignite a dust / air mixture and thereby initiate a secondary dust explosion. The expected reduced explosion over-pressure of such a secondary dust explosion may be much higher than in case of a single vessel explosion. For the first time an empirical mathematical model for calculating the flame front propagation time inside a connecting pipe after a dust explosion in a connected explosion vessel has been developed. The model is validated for dust and gas explosions in different vessels, independently of whether the explosion vessels are vented or closed and for different diameters of the connecting pipe. A numerical simulation model for dust explosions in closed spherical vessels was written in a C comparable language which runs under Windows 3.11 and Windows 95 on a standard PC. The validation of this numerical model is in good accordance with measurement results of real dust explosions. The model shows good agreement with data from explosions in closed vessels for maize starch, aluminium and magnesium dusts and propane gas. In vented vessels in some cases for maize starch good agreement is also shown.
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Roach, Matthew Douglas. "Physically based simulation of explosions." Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/2409.
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This thesis describes a method for using physically based techniques to model an explosion and the resulting side effects. Explosions are some of the most visually exciting phenomena known to humankind and have become nearly ubiquitous in action films. A realistic computer simulation of this powerful event would be cheaper, quicker, and much less complicated than safely creating the real thing. The immense energy released by a detonation creates a discontinuous localized increase in pressure and temperature. Physicists and engineers have shown that the dissipation of this concentration of energy, which creates all the visible effects, adheres closely to the compressible Navier-Stokes equation. This program models the most noticeable of these results. In order to simulate the pressure and temperature changes in the environment, a three dimensional grid is placed throughout the area around the detonation and a discretized version of the Navier-Stokes equation is applied to the resulting voxels. Objects in the scene are represented as rigid bodies that are animated by the forces created by varying pressure on their hulls. Fireballs, perhaps the most awe-inspiring side effects of an explosion, are simulated using massless particles that flow out from the center of the blast and follow the currents created by the dissipating pressure. The results can then be brought into Maya for evaluation and tweaking.
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Dounia, Omar. "Numerical investigation of gas explosion phenomena in confined and obstructed channels." Phd thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/20584/1/DOUNIA_Omar.pdf.
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Mining, process and energy industries suffer from billions of dollars of worldwide losses every year due to Vapour Cloud Explosions (VCE). Moreover, explosion accidents are often tragic and lead to a high number of severe injuries and fatalities. The VCE scenario is complex and controlled by various mechanisms. The interplay among them is still not entirely understood. Understanding all these intricate processes is of vital importance and requires detailed experimental diagnostics. Coupling accurate numerical simulations to well documented experiments can allow an elaborate description of these phenomena. This thesis focuses on explosions occurring on configurations that are either semi-confined or confined. In such configurations, the explosion is generally initiated by a mild ignition and a subsonic flame front emerges from the ignition source. An important feature of self-propagating flames lies in their intrinsically unstable nature. When they propagate in an environment with high levels of confinement and congestion, which is the case in most industrial sites, a Flame Acceleration (FA) process is often observed that can give rise to very fast flames, known for their destructive potential. In some cases, the FA process can create the appropriate conditions for the initiation of detonations, which corresponds to a rapid escalation of the explosion hazard. To reproduce the confinement and congestion conditions that one can find in industrial sites, the university of Munich TUM equipped a confined chamber with a series of obstacles and analysed the influence of repeated obstructions on the propagation of hydrogen/air deflagrations. This experimental study showed a strong influence of the mixture composition on the acceleration process. A Deflagration to Detonation Transition (DDT) has also been observed for a certain range of equivalence ratio. This configuration is therefore ideal to study the mechanisms of flame acceleration as well as the intricate DDT process. A numerical study of both scenarios is performed in this thesis: -First for a lean premixed hydrogen/air mixture, a strong flame acceleration is observed experimentally without DDT. The characteristic features of the explosion are well reproduced numerically using a Large Eddy Simulation (LES) approach. The crucial importance of confinement and repeated flame-obstacle interactions in producing very fast deflagrations is highlighted. -DDT is observed experimentally for a stoichiometric hydrogen/air mixture. This thesis focuses on the instants surrounding the DDT event, using Direct Numerical Simulations (DNS). Particular attention is drawn to the impact of the chemistry modelling on the detonation scenario. The failure of preventive measures is often observed in many explosion accidents. To avoid a rapid escalation of the explosion scenario, mitigative procedures must be triggered when a gas leak or an ignition is detected. Metal salts (like potassium bicarbonate and sodium bicarbonate) have received considerable attention recently because well-controlled experiments showed their high efficiency in inhibiting fires. The last part of the thesis focused on the mechanism of flame inhibition by sodium bicarbonate particles. First, criteria based on the particle sizes are established to characterize the inhibition efficiency of the particles. Second, two dimensional numerical simulations of a planar flame propagating in a stratified layer of very fine sodium bicarbonate particles showed that under certain conditions these powders can act as combustion enhancers. These results echo a number of experimental observations on the possible counter-effects of the inhibitors.
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Socha, Jessica. "Graph-Based Fracture Models for Rigid Body Explosions." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1105.
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Explosions are one of the most powerful and devastating natural phenomena. The pressure front from the blast wave of an explosion can cause fracture of objects in its vicinity and create flying debris. In this thesis, I outline a previously proposed explosion model. An explosion is treated as a fluid with its behaviour governed by the Navier-Stokes equations and the gaseous products modeled using particles. Explosions are simulated as a means for initiating fracture of rigid bodies in the vicinity of an explosion. In contrast to fracture models that are based on physics, I propose a new approach to simulating fracture which treats fracturing the rigid body as a pre-processing step. A rigid body can be pre-fractured by treating it as graph and using one of the two proposed graph partitioning algorithms to divide the object into the desired number of pieces. By treating fracture as a pre-processing step, much less computation need be done during the simulation than models based on physics.
It is shown that the recursive breadth-first search graph partitioning algorithm produces physically realistic results for shattering windows that are consistent with observations of real broken windows. The curvature-driven spectral partitioning algorithm fractures objects into two pieces where the object is weakest, where weakest is defined by the area with largest curvature. Numerical simulations of explosions and fracture were conducted to produce data that was used by a ray tracer and volume renderer to create images which were assembled into animations.
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Ilieva, Ralitsa S. "Gamma-Ray spectroscopy studies of explosive stellar phenomena." Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/845495/.
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A handful of nuclear reactions have been identified as vital for our understanding of explosive stellar phenomena and the nucleosynthesis associated with these scenarios. The 22Ne(α, γ)26Mg reaction in massive stars is responsible for using the neon fuel required for the 22Ne(α, n) 25 Mg, which is a key source of neutrons in these environments. Cl(p, γ) 35 Ar reaction affects the final abundance of 34 S which could be used as an identifier of nova origin of presolar grains. The rate of these reactions is predicted to be dominated by a number of resonant states above the α- and proton-emission thresholds, respectively. Consequently, by determining the nuclear properties of such resonant states it is possible to estimate the 22 Ne(α, γ) 26 Mg and 34Cl(p, γ)35Arreaction rates. In this thesis work, the 11B(16O,p)26Mg and 9Be(28Si,2n)35Ar fusion-evaporation reactions were used to populate excited states in the 26Mg and 35Ar nuclei, respectively. The beams of 16O and 28Si were produced by the Argonne Tandem Linear Accelerator System and prompt electromagnetic radiation was detected using the GAMMASPHERE detector array, which, in the case of the 35Ar experiment, was used in coincidence with recoil selection provided by the Argonne Fragment Mass Analyzer. The two γ-ray spectroscopy studies performed in this work allowed a determination of the nuclear properties of astrophysically important γ-decaying states, which, in turn, were used to re-evaluate the 22 Ne(α, γ)26Mg and 34Cl(p,γ)35Ar stellar reaction rates.
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Ruiz, C. "Aspects of nuclear phenomena under explosive astrophysical conditions." Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/11338.
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Semeraro, Emanuele. "Experimental investigation on hydrodynamic phenomena associated with a sudden gas expansion in a narrow channel." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066516/document.
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La vaporisation rapide du sodium liquide surchauffé est supposée être à l’origine des arrêts automatiques pour réactivité négative du réacteur Phénix.Un dispositif expérimental a été mis en œuvre pour reproduire la détente d'un gaz pressurisé, repoussant un liquide dans un canal de section rectangulaire très allongée.L’interface qui sépare les deux fluides, initialement plate, ondule du fait d'instabilités de Rayleigh-Taylor dont le caractère 2D est garanti par le rapport d'aspect de la section du canal. L’aire interfaciale augmente d'un facteur 50.L’expansion du gaz peut être divisée en deux phases principales : une phase dite « de Rayleigh-Taylor » (linéaire et non-linéaire) et une phase dite « à multi-structures » (transitionnelle et chaotique). La première est caractérisée par la dynamique de l'interface et l’aire interfaciale qui en résulte est proportionnelle à l’amplitude des ondulations. La deuxième est influencée par le comportement des structures liquides, dispersées dans la matrice gazeuse et l’aire interfaciale est alors proportionnelle au nombre de structures.La distribution de fraction volumique suggère un modèle d’écoulement composé de trois régions : une région où la frontière des bulles est clairement définie et régulière, une région compartimentée par des membranes liquides issues des frontières des bulles, une région diphasique formée de la queue de ces structures. L’analyse de sensibilité à la tension superficielle confirme que plus la tension est faible, plus les interfaces sont instables. Les ondes sont plus prononcées et plus de structures sont produites, ce qui conduit à une majoration du taux de production de l’aire interfacialeThe sharp vaporization of superheated liquid sodium is investigated. It is suspected to be at the origin of the automatic shutdown for negative reactivity, occurred in the Phénix reactor at the end of the eighties.An experimental apparatus has been designed and operated to reproduce the expansion of overpressurized air, superposed to water in a narrow vertical rectangular section channel.When expansion begins, the initial flat interface separating the two fluids becomes corrugated under the development of two-dimensional Rayleigh-Taylor instabilities. The interface area increases significantly and becomes even 50 times larger than the initial value. Since the channel is very narrow, instabilities along the channel depth do not develop.The gas expansion in a narrow channel can be divided into two main phases: Rayleigh-Taylor (linear and non-linear) and multi-structures (transition and chaotic) phases. The former is characterized by the dynamic of corrugated profile and the interface area results proportional to the amplitude of corrugation The latter is influenced by the behavior of the liquid structures dispersed in gas matrix and the interface area is mainly proportional to the number of liquid structures.The distribution of volume fraction suggests a model of channel flow consisting of three regions: the regular profile of peaks, the spike region and the structures tails. The analysis of sensibility to surface tension confirms that, with a lower surface tension, the fluids configuration is more unstable. The interface corrugations are more pronounced and more structures are produced, leading to a higher increment of the interface area
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Guereca, Gloria Romera. "Explosive vaporization in microenclosures and boiling phenomena on submicron thin film strip heaters /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17032.
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Arumugham, Achari Ajith Kumar. "Numerical simulation of fluid dynamics and transport phenomena in electrostatically charged volatile sprays." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/277387.
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Els electrosprays estan constituïts de microgotes amb alta càrrega elèctrica i en moviment sota l'acció de forces electrostàtiques. Les gotes es generen com a resultat de la ruptura d'un doll de líquid sotmès a un camp elèctric prou fort. Les gotetes generades per tant, són transportats sota la influència combinada del gradient electrostàtic entre l'emissor i la contraplaca, la interacció amb la càrrega de les gotes del voltant i la força de la resistència aerodinàmica. La major part de les aplicacions de electrospray impliquen l'evaporació de les gotes com a part fonamental per aconseguir el resultat desitjat.
Quan un conjunt de partícules d'aerosol es mou amb una velocitat neta en relació amb el gas circumdant, les partícules exerceixen una força d'arrossegament sobre el gas que causa el moviment del gas. En electrosprays, aquest moviment del gas és induït per les microgotes altament carregades sota l'acció de forces electrostàtiques. Mentre que molts models numèrics no han considerat el flux de gas induït en les simulacions numèriques de electrosprays, l'evidència experimental mostra que aquesta velocitat del gas modifica el comportament del esprai a nivell local. Considerant la incidència que aquest moviment del gas pot tenir en l'evaporació de gotetes en electrosprays volàtils, es fa evident que és necessari disposar d'una metodologia per a la simulació de la dinàmica de electrosprays que inclogui aquest aspecte. A més, ja que el moviment de gas també influeix en el moviment de les gotes, la formulació ha de considerar que aquests moviments són completament acoblats (és a dir, acoblats en les dues direccions). Aquests models més complets han de ser capaços de dilucidar la influència del flux de gas induït en variables d'importància pràctica, com ara són el patró de flux de deposició a la contraplaca, l'eixamplament del plomall, la distribució de densitat de nombre de gotes, i també en la predicció de l'evaporació de les gotes.
En aquest treball s'ha desenvolupat un esquema numèric integral que acobla completament la dinàmica Lagrangiana de les gotes de l'electrospray amb els efectes del flux de gas induït, les explosions de Coulomb, i el transport de vapor de dissolvent, així com de la càrrega que deixen darrera les gotes que s'esvaeixen en els electrospray volàtils. S'han desenvolupat codis diferents per a simular cada fenomen per separat els quals s'han executat seqüencialment i de manera iterativa fins aconseguir la convergència de totes les variables.
Aquesta metodologia ha estat aplicada per comparar els efectes d'evaporació en tres sistemes d'electrospray amb dissolvents de diferent volatilitat: acetona, metanol i n-heptà. Les gotes es van injectar en els tres sistemes amb una distribució de diàmetres log-normal unimodal amb un valor mitjà de 8 μm, i un coeficient de variació del 10%. Explosions de Coulomb intenses s'han observat dins l'esprai en forma de bandes diagonals (en el domini 2D). El transport de vapor en aquests sistemes és predominantment per convecció forçada en lloc de pura difusió. La concentració més alta de vapor s'observa prop de la zona d'injecció per a tots els tres sistemes, concentració que decau ràpidament a partir de llavors, tant en sentit radial com axial. En els tres casos, cap o poques gotes arriben a la contraplaca situada 3 cm sota del broquet capil•lar, posant en evidencia la necessitat de tenir en compte l'evaporació en les simulacions d'aquests sistemes.Los electrosprays están constituidos de microgotas altamente cargadas i en movimiento bajo la acción de fuerzas electrostáticas. Las gotas se generan como resultado de la ruptura de un chorro de líquido sometido a un campo eléctrico suficientemente fuerte. Las gotas generadas por lo tanto, son transportadas bajo la influencia combinada del gradiente electrostático entre el emisor y contraplaca, la interacción con la carga de las gotas de los alrededores y la fuerza de la resistencia aerodinámica. La mayor parte de las aplicaciones de electrosprays implican la evaporación de gotitas como un aspecto fundamental para lograr el resultado deseado. Cuando un sistema de partículas de aerosol se mueve con una velocidad neta en relación con el gas circundante, las partículas ejercen una fuerza de arrastre sobre el gas que causa que el movimiento del gas. En electrosprays, este movimiento de gas es inducido por las microgotas altamente cargadas bajo la acción de fuerzas electrostáticas. Mientras que muchos modelos numéricos no han considerado el flujo de gas inducido en las simulaciones numéricas de electrosprays, la evidencia experimental muestra que la velocidad del gas modifica el comportamiento del spray a nivel local. Considerando la incidencia que puede tener en la evaporación de gotitas en electrosprays volátiles, es evidente la necesidad de una metodología general para la simulación de la dinámica de electrosprays que incluyan este aspecto. Adicionalmente, ya que el movimiento del gas también influye en el movimiento de las gotas, la formulación debe considerar que estos movimientos están completamente acoplados (es decir, acoplados en las dos direcciones). Estos modelos más completos deberían ser capaces de dilucidar la influencia del flujo de gas inducida en las variables de importancia práctica, tales como el patrón de flujo de deposición en la contraplaca, el ensanchamiento del penacho, la distribución de densidad de número de gotas, y también en la predicción de la evaporación de las gotas. En este trabajo se ha desarrollado un esquema numérico integral que acopla completamente la dinámica de gotas electrospray de Lagrange con los efectos del flujo de gas inducido, las explosiones de Coulomb, y el transporte de vapor de disolvente, así como de la carga que dejan detrás las gotas que se desvanecen en los electrosprays volátiles. Se han desarrollado códigos diferentes para simular cada fenómeno por separado y se han ejecutado secuencialmente y de manera iterativa hasta conseguir la convergencia de todas las variables. Esta metodología se ha aplicado para comparar los efectos de evaporación en tres sistemas de electrospray con disolventes de diferente volatilidad: acetona, metanol y n-heptano. Las gotas se inyectaron en los tres sistemas con una distribución de diámetros log-normal unimodal con un valor medio de 8 µm, y un coeficiente de variación de 10%. Intensas explosiones de Coulomb se han observado dentro del spray en forma de bandas diagonales (en el dominio 2D). El transporte de vapor en estos sistemas es predominantemente por convección forzada en lugar de pura difusión. La más alta concentración de vapor se observa cerca de la zona de inyección para todos los tres sistemas, concentración que decae rápidamente a partir de entonces, en sentido tanto radial como axial. En los tres casos, pocas o ninguna gota llega a la contraplaca situada 3 cm por debajo de la boquilla capilar, poniendo en evidencia la necesidad de tener en cuenta la evaporación en la simulación de estos sistemas.
Electrosprays are constituted of highly charged micro drops moving under the action of electrostatic forces. They are generated as a result of the breakup of a liquid jet subjected to a sufficiently strong electric field. The droplets hence generated are transported under the combined influence of the electrostatic gradient between the emitter and counterplate, the interaction with the spray charge and the aerodynamic drag force. Most of the electrospray applications involve droplet evaporation as a critical aspect in achieving their desired result. When a collection of aerosol particles move with a net velocity relative to the surrounding gas, it exerts a drag force on the gas which can cause the gas to flow. In electrosprays, this gas motion is induced by the highly charged micro-drops moving under the action of electrostatic forces. While many numerical models have neglected induced gas flow in the numerical simulations of electrosprays, experimental evidence shows that the gas speed can be significant locally. Also considering the importance it can have in droplet evaporation in volatile electrosprays, there is a need for a general methodology to include the induced gas flow caused by the droplets in current numerical models of electrospray dynamics. Furthermore, since the gas motion also influences the droplet motion, a formulation that can accurately describe these motions should be fully coupled (i.e., two-way coupled). Such improved models should be able to elucidate the influence of the induced gas flow on variables of practical importance such as the flux deposition pattern on the counterplate, plume spread, droplet number density distribution, and also in the prediction of droplet evaporation. We developed a comprehensive numerical scheme which fully couples the Lagrangian electrospray droplet dynamics with the effects of induced gasflow, Coulomb explosions, and the transport of solvent vapor as well as charge left over by vanishing droplets in volatile electrospray systems. Separate codes for the diverse phenomena were developed. These codes have been run sequentially and in an iterative way until convergence was attained for all variables. This methodology has been applied to compare the evaporation effects in three electrospray systems with solvents of different volatility: acetone, methanol and n-heptane. The droplets were injected into the three systems with unimodal and log-normal distributed diameters with a mean value of 8 μm, and a coefficient of variation of 10%. Regions of intense Coulomb explosion events in form of diagonal bands (in the 2D domain) within the spray are well captured. We observe that the vapor transport in these systems is predominantly by forced convection rather than diffusion. Highest vapor concentration is observed near the injection zone for all the three systems, which rapidly decays thereafter, both radially as well as axially. In all three cases, few or no droplets arrive at the counterplate located 3 cm down the capillary nozzle, highlighting the relevance of accounting for evaporation when simulating these systems.
Books on the topic "Explosion Phenomenon"
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International Colloquium on Dynamics of Explosions and Reactive Systems (12th 1989 Ann Arbor, Mich.). Dynamics of detonations and explosions--explosion phenomena. Washington, DC: American Institute of Aeronautics and Astronautics, 1991.
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The detonation phenomenon. Cambridge: Cambridge University Press, 2008.
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L, Kuhl A., ed. Dynamic aspects of explosion phenomena. Washington, DC: American Institute of Aeronautics and Astronautics, Inc., 1993.
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M, Hasan M., and United States. National Aeronautics and Space Administration., eds. Explosive boiling at very low heat fluxes: A microgravity phenomenon. [Washington, DC]: National Aeronautics and Space Administration, 1993.
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International Symposium on Explosion, Shock Wave & High-Energy Reaction Phenomena (3rd 2010 Seoul, Korea). Explosion, shock wave and high energy reaction phenomena: Selected, peer reviewed papers from International Symposium on Explosion, Shock wave & High-energy reaction Phenomena 2010 (3rd ESHP Symposium), 1-3 September 2010, Seoul National University, Seoul, Korea. Stafa-Zurich, Switzerland: Trans Tech Publications, 2011.
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International Symposium on Explosion, Shock Wave and Hypervelocity Phenomena (2nd 2007 Kumamoto, Japan). Explosion, shock wave and hypervelocity phenomena in materials II: Selected peer reviewed papers from the 2nd International Symposium on Explosion, Shock Wave and Hypervelocity Phenomena (ESHP-2), 6-9 March 2007, Kumamoto, Japan. Stafa-Zurich, Switzerland: Trans Tech Publications, 2008.
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Rubtsov, Nickolai, Mikhail Alymov, Alexander Kalinin, Alexey Vinogradov, Alexey Rodionov, and Kirill Troshin. Remote studies of combustion and explosion processes based on optoelectronic methods. au: AUS PUBLISHERS, 2022. http://dx.doi.org/10.26526/monography_62876066a124d8.04785158.
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The main objective of this book is to acquaint the reader with the main modern problems of
the multisensor data analysis and opportunities of the hyperspectral shooting being carried out in the
wide range of wavelengths from ultraviolet to the infrared range, visualization of the fast combustion
processes of flame propagation and flame acceleration, the limit phenomena at flame ignition and
propagation. The book can be useful to students of the high courses and scientists dealing with problems
of optical spectroscopy, vizualisation, digital recognizing images and gaseous combustion.
The main goal of this book is to bring to the attention of the reader the main modern
problems of multisensory data analysis and the possibilities of hyperspectral imaging, carried out
in a broad wave-length range from ultraviolet to infrared by methods of visualizing fast combustion
processes, propagation and flames acceleration, and limiting phenomena during ignition and flame
propagation. The book can be useful for students of higher courses and experimental scientists dealing
with problems of optical spectroscopy, visualization, pattern recognition and gas combustion.
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International Workshop on Shock Wave Focusing Phenomena in Combustible Mixtures: Ignition and Transition to Detonation of Reactive Media under Geometrical Constraints (1998 Aachen, Germany). Proceedings of the International Workshop on Shock Wave Focusing Phenomena in Combustible Mixtures: Ignition and Transition to Detonation of Reactive Media under Geometrical Constraints, December 15-16, 1998. Aachen: Shaker, 2000.
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History of shock waves, explosions and impact: A chronological and biographical reference. Berlin: Springer, 2009.
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Krehl, Peter O. K. History of shock waves, explosions and impact: A chronological and biographical reference. Berlin: Springer, 2009.
Find full textBook chapters on the topic "Explosion Phenomenon"
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Kimura, Satoshi, Hidehiro Hata, Tetsuyuki Hiroe, Kazuhito Fujiwara, and Hideaki Kusano. "Analysis of Explosion Combustion Phenomenon with Ammonium Nitrate." In Explosion, Shock Wave and Hypervelocity Phenomena, 213–18. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-465-0.213.
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Willis, David A. "Stress Generation in Laser-Material Interaction: Phase Explosion Phenomenon." In Encyclopedia of Thermal Stresses, 4599–607. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-007-2739-7_9.
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Korenevskaya, Maria, Oleg Zayats, Alexander Ilyashenko, and Vladimir Muliukha. "The Phenomenon of Secondary Flow Explosion in Retrial Priority Queueing System with Randomized Push-Out Mechanism." In Lecture Notes in Computer Science, 236–46. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-01168-0_22.
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Liu, Zhi Yue, and Muhamed Suceska. "Numerical Prediction on Cookoff Explosion of Explosive under Strong Confinement." In Explosion, Shock Wave and Hypervelocity Phenomena, 89–94. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-465-0.89.
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Takayama, Kazuyoshi. "Explosion in Gases." In Visualization of Shock Wave Phenomena, 479–517. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-19451-2_8.
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Doschek, G. A., S. K. Antiochos, E. Antonucci, C. C. Cheng, J. L. Culhane, G. H. Fisher, C. Jordan, et al. "Chromospheric Explosions." In Energetic Phenomena on the Sun, 303–75. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2331-7_4.
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Peng, Xiaofeng. "Explosive Boiling." In Micro Transport Phenomena During Boiling, 233–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-13454-8_9.
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Costanzo, Frederick A. "Underwater Explosion Phenomena and Shock Physics." In Structural Dynamics, Volume 3, 917–38. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-9834-7_82.
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Rolc, S., Vladislav Adamík, J. Buchar, and L. Severa. "Plate Response to Buried Charge Explosion." In Explosion, Shock Wave and Hypervelocity Phenomena, 83–88. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-465-0.83.
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Vasilev, Eugene I., Tov Elperin, and Gabi Ben-Dor. "Reconsideration of the So-Called von Neumann Paradox in the Reflection of a Shock Wave over a Wedge." In Explosion, Shock Wave and Hypervelocity Phenomena, 1–8. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-465-0.1.
Full textConference papers on the topic "Explosion Phenomenon"
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Jurca, Adrian Marius, Mihaela Paraian, Mirela Ancuta Radu, Mihai Catalin Popa, and Dan Gabor. "ANALYSE OF EXPLOSION CHARACTERISTICS OF WOOD DUST CLOUDS IN DEPENDENCE OF THE PARTICLE SIZE DISTRIBUTION." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/5.1/s20.002.
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Many processes involving dusts, suspended or accumulated, have the potential to lead to fire, explosion or decomposition in the presence of oxygen and an ignition source. The risk of dust explosions increases as more and more products take the form of dusts or require the use of dusts during manufacture. In spite of extensive research and development to prevent and mitigate dust explosions in the process industries, this phenomenon continues to represent a constant hazard to industries including manufacturing, using and handling of combustible dust material. The purpose of explosion preventing and protection measures is to prevent explosion occurrence, by eliminating or avoiding the conditions leading to explosions. The dust explosion and combustion characteristics are required to be known, in order to suitably choose and draw up the preventive and protection measures. Once known, the protection/prevention measures can be correlated with the safety characteristics. The aim of this paper is to analyze of explosion and combustion characteristics of wood dust clouds in dependence of the particle size distribution. The paper shows the importance of knowing the explosive characteristics of dusts and identifying the factors of influence in obtaining the results.
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Hu, Yang, Jinyang Zheng, and Li Ma. "Dynamic Fracture and Anti-Explosion Capacity Investigation of Composite Explosion Containment Vessel." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78496.
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Explosion containment vessels (ECVs) have been widely used as they can contain the shock wave and products from high explosions. Recently, there has been an increased interest in composite materials using in ECVs because of their advantages of high specific strength, reduced maintenance costs, and improved corrosion resistance. In this paper, an experiment was carried out using two e-glass/epoxy composite ECVs with an aluminum alloy inner layer to investigate the dynamic fracture and anti-explosion capacity of composite ECVs. The experiment contains two stages. In the first stage, two vessels were tested using 10g and 20g explosive charge, respectively. Dynamic circumferential and axial strain was measured. The vessel under the blast of 10g explosive was in good condition while the other one was failure as a through crack appeared. In the second stage, a large explosive charge of 30g was detonated at the center of vessel and the vessel was damaged seriously. The fracture characteristic is described in detail. The experimental results show that the range of the anti-explosion capacity ζ is between 1.43% and 2.87% which is much higher than that of single layer ECVs and also higher than that mentioned in other literature. A three-dimensional finite element analysis model is established using the ALE method based on ANSYS/LS-DYNA to simulate the experiment results of experimental vessel under the explosive loading. Good agreement between experimental and numerical results can be obtained by comparing the bulging phenomenon and hoop strain around the explosion center. The numerical results also show that the delamination appears and the delamination between the inner metal layer and adjacent composite layer is especially obvious.
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Huang, XiangXin, and GuiCheng Lu. "THE DISCOVERY OF "SLIGHT EXPLOSION" PHENOMENON AND STUDY OF ANTI-EXPLOSION ARCH IN STOKER FIRING." In Energy and Environment, 1995. Connecticut: Begellhouse, 2023. http://dx.doi.org/10.1615/1-56700-052-5.1000.
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Hagos, Ftwi Y., A. Rashid A. Aziz, and Isa M. Tan. "Water-in-diesel emulsion and its micro-explosion phenomenon-review." In 2011 IEEE 3rd International Conference on Communication Software and Networks (ICCSN). IEEE, 2011. http://dx.doi.org/10.1109/iccsn.2011.6014903.
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Pan Liu, Irene Tee, Soo Sien Seah, Chi Wen Soo, Ye Chen, and Zhi Qiang Mo. "Explosion phenomenon of high resistance via during TEM sample preparation using FIB." In 2010 IEEE International Reliability Physics Symposium. IEEE, 2010. http://dx.doi.org/10.1109/irps.2010.5488816.
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Balagansky, I., K. Hokamoto, P. Manikandan, A. Matrosov, I. Stadnichenko, H. Miyoshi, Mark Elert, et al. "PHENOMENON OF ENERGY FOCUSING IN EXPLOSION SYSTEMS WHICH INCLUDE HIGH MODULUS ELASTIC ELEMENTS." In SHOCK COMPRESSION OF CONDENSED MATTER 2009: Proceedings of the American Physical Society Topical Group on Shock Compression of Condensed Matter. AIP, 2009. http://dx.doi.org/10.1063/1.3295102.
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Liu, Zhenhui, and Ragnar Igland. "Numerical Simulation of a Subsea Pipeline Subjected to Near-Field Underwater Explosion Loads With the Coupled Eulerian-Lagrangian (CEL) Method." In ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-80657.
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Abstract An underwater unexploded ordnance (UXO) for example a mine filled with trinitrotoluene (also known as TNT), may present a potential threat to subsea structures. An explosion is a complicated physical phenomenon as it involves the interactions among water, seabed, the structure, and the explosive ordnance. The relevance of the paper is the need for removal of a large number of UXO on the Norwegian continental shelf during the installation of subsea pipelines. Numerical simulations have been used to calculate the effect of an explosion, but normally with an assumption of free explosion space. The seabed effects are simply considered by exaggerating the explosive weight with an empirical factor. This paper tries to include the real seabed effects in a near-field explosion underwater explosion events by using the Coupled Eulerian-Lagrangian (CEL) method. The effect of water, soil and the TNT are approached by using the Eulerian formulation with specified Equation of status (EOS). The Us-Up’s form of Mie-Gruneisen equation is used for the water and soil. The soil’s strength is described by linear Drucker-Prager yielding function. The Jones-Wilkins-Lee (JWL) equation of state is used for TNT. The steel is approached by shell elements in a Lagrangian scheme. The strain rate effects have been considered through the Cowper and Symonds equation. The coupling between Eulerian and Lagrangian formulation is done by the general contact features provided by Abaqus Explicit solver. The simulation results are discussed in details with respect to the water, soil and pipeline deformations respectively. Additionally, the axial force is also discussed. It is shown that the seabed plays an important role during the explosion and the empirical factor used to exaggerate the TNT mass is over-conservative. In the near-field explosion, the existence of soil may be beneficial to the pipeline’s damage. Global effects may be also triggered due to the large axial force generated during the explosion.
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Kim, Seung-Huyn, Yoon-Suk Chang, and Yong-Jin Cho. "Reactor Cavity Analysis Under Steam Explosive Conditions by TNT Model." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63224.
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Steam explosion may occur in nuclear power plants by fuel-coolant interactions when the external reactor vessel cooling strategy is failed. This phenomenon can cause shock wave that endangers surrounding reactor cavity wall due to resulting dynamic effects. Even though extensive researches have been performed to predict influences of the steam explosion, due to complexity of physical phenomena and thermal-hydraulic conditions, it is remained as one of possible hazards. The object of this study is to examine characteristics of reactor cavity and nuclear components under representative steam explosion conditions. In this context, an assembled finite element mesh was generated and evaluated by the trinitrotoluene model. As a result, stresses, strains and displacements of the reactor cavity and nuclear components were calculated. Subsequently, crack evaluation of reinforced concrete was performed and their results were discussed.
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Shubin, O. N., V. Z. Nechai, V. N. Nogin, D. V. Petrov, and V. A. Simonenko. "Nuclear Explosion Near Surface of Asteroids and Comets - II. General Description of the Phenomenon." In Fifth International Conference on Space. Reston, VA: American Society of Civil Engineers, 1996. http://dx.doi.org/10.1061/40177(207)11.
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Lebedev, Michael A. "Dissymmetrization of a powerful explosion: experiment and hypothesis on possible reasons for the phenomenon." In Twenty-Third International Congress on High-Speed Photography and Photonics, edited by Valentina P. Degtyareva, Mikhail A. Monastyrski, Mikhail Y. Schelev, and Alexander V. Smirnov. SPIE, 1999. http://dx.doi.org/10.1117/12.350503.
Full textReports on the topic "Explosion Phenomenon"
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Judge, K. J. Installation and use of a quantimet 720 image analyzer for particle characterization. Natural Resources Canada/CMSS/Information Management, 1989. http://dx.doi.org/10.4095/331777.
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The size and shape of particles, in a dust, can affect the explosion hazards posed by the dust. Dust explosion work at the Canadian Explosive Atmospheres Laboratory (CEAL) now involves the use of an image analyzer. The analyzer is being used to characterize the shape and size of grains involved in explosion tests at this laboratory. It is hoped that this information will indicate the relationships between these parameters and that a more comprehensive prediction of dust explosion phenomena will result. The system configuration, operating procedures and supporting hardware and software are detailed in this report.
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Richards, Paul G., Tatyana G. Rautian, Vitaly I. Khalturin, and W. Scott Phillips. Explosion Source Phenomena Using Soviet, Test-Era, Waveform Data. Office of Scientific and Technical Information (OSTI), April 2006. http://dx.doi.org/10.2172/881052.
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Snyder, Victor A., Dani Or, Amos Hadas, and S. Assouline. Characterization of Post-Tillage Soil Fragmentation and Rejoining Affecting Soil Pore Space Evolution and Transport Properties. United States Department of Agriculture, April 2002. http://dx.doi.org/10.32747/2002.7580670.bard.
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Tillage modifies soil structure, altering conditions for plant growth and transport processes through the soil. However, the resulting loose structure is unstable and susceptible to collapse due to aggregate fragmentation during wetting and drying cycles, and coalescense of moist aggregates by internal capillary forces and external compactive stresses. Presently, limited understanding of these complex processes often leads to consideration of the soil plow layer as a static porous medium. With the purpose of filling some of this knowledge gap, the objectives of this Project were to: 1) Identify and quantify the major factors causing breakdown of primary soil fragments produced by tillage into smaller secondary fragments; 2) Identify and quantify the. physical processes involved in the coalescence of primary and secondary fragments and surfaces of weakness; 3) Measure temporal changes in pore-size distributions and hydraulic properties of reconstructed aggregate beds as a function of specified initial conditions and wetting/drying events; and 4) Construct a process-based model of post-tillage changes in soil structural and hydraulic properties of the plow layer and validate it against field experiments. A dynamic theory of capillary-driven plastic deformation of adjoining aggregates was developed, where instantaneous rate of change in geometry of aggregates and inter-aggregate pores was related to current geometry of the solid-gas-liquid system and measured soil rheological functions. The theory and supporting data showed that consolidation of aggregate beds is largely an event-driven process, restricted to a fairly narrow range of soil water contents where capillary suction is great enough to generate coalescence but where soil mechanical strength is still low enough to allow plastic deforn1ation of aggregates. The theory was also used to explain effects of transient external loading on compaction of aggregate beds. A stochastic forInalism was developed for modeling soil pore space evolution, based on the Fokker Planck equation (FPE). Analytical solutions for the FPE were developed, with parameters which can be measured empirically or related to the mechanistic aggregate deformation model. Pre-existing results from field experiments were used to illustrate how the FPE formalism can be applied to field data. Fragmentation of soil clods after tillage was observed to be an event-driven (as opposed to continuous) process that occurred only during wetting, and only as clods approached the saturation point. The major mechanism of fragmentation of large aggregates seemed to be differential soil swelling behind the wetting front. Aggregate "explosion" due to air entrapment seemed limited to small aggregates wetted simultaneously over their entire surface. Breakdown of large aggregates from 11 clay soils during successive wetting and drying cycles produced fragment size distributions which differed primarily by a scale factor l (essentially equivalent to the Van Bavel mean weight diameter), so that evolution of fragment size distributions could be modeled in terms of changes in l. For a given number of wetting and drying cycles, l decreased systematically with increasing plasticity index. When air-dry soil clods were slightly weakened by a single wetting event, and then allowed to "age" for six weeks at constant high water content, drop-shatter resistance in aged relative to non-aged clods was found to increase in proportion to plasticity index. This seemed consistent with the rheological model, which predicts faster plastic coalescence around small voids and sharp cracks (with resulting soil strengthening) in soils with low resistance to plastic yield and flow. A new theory of crack growth in "idealized" elastoplastic materials was formulated, with potential application to soil fracture phenomena. The theory was preliminarily (and successfully) tested using carbon steel, a ductile material which closely approximates ideal elastoplastic behavior, and for which the necessary fracture data existed in the literature.
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Microbiology in the 21st Century: Where Are We and Where Are We Going? American Society for Microbiology, 2004. http://dx.doi.org/10.1128/aamcol.5sept.2003.
Full textAbstract:
The American Academy of Microbiology convened a colloquium September 5–7, 2003, in Charleston, South Carolina to discuss the central importance of microbes to life on earth, directions microbiology research will take in the 21st century, and ways to foster public literacy in this important field. Discussions centered on: the impact of microbes on the health of the planet and its inhabitants; the fundamental significance of microbiology to the study of all life forms; research challenges faced by microbiologists and the barriers to meeting those challenges; the need to integrate microbiology into school and university curricula; and public microbial literacy. This is an exciting time for microbiology. We are becoming increasingly aware that microbes are the basis of the biosphere. They are the ancestors of all living things and the support system for all other forms of life. Paradoxically, certain microbes pose a threat to human health and to the health of plants and animals. As the foundation of the biosphere and major determinants of human health, microbes claim a primary, fundamental role in life on earth. Hence, the study of microbes is pivotal to the study of all living things, and microbiology is essential for the study and understanding of all life on this planet. Microbiology research is changing rapidly. The field has been impacted by events that shape public perceptions of microbes, such as the emergence of globally significant diseases, threats of bioterrorism, increasing failure of formerly effective antibiotics and therapies to treat microbial diseases, and events that contaminate food on a large scale. Microbial research is taking advantage of the technological advancements that have opened new fields of inquiry, particularly in genomics. Basic areas of biological complexity, such as infectious diseases and the engineering of designer microbes for the benefit of society, are especially ripe areas for significant advancement. Overall, emphasis has increased in recent years on the evolution and ecology of microorganisms. Studies are focusing on the linkages between microbes and their phylogenetic origins and between microbes and their habitats. Increasingly, researchers are striving to join together the results of their work, moving to an integration of biological phenomena at all levels. While many areas of the microbiological sciences are ripe for exploration, microbiology must overcome a number of technological hurdles before it can fully accomplish its potential. We are at a unique time when the confluence of technological advances and the explosion of knowledge of microbial diversity will enable significant advances in microbiology, and in biology in general, over the next decade. To make the best progress, microbiology must reach across traditional departmental boundaries and integrate the expertise of scientists in other disciplines. Microbiologists are becoming increasingly aware of the need to harness the vast computing power available and apply it to better advantage in research. Current methods for curating research materials and data should be rethought and revamped. Finally, new facilities should be developed to house powerful research equipment and make it available, on a regional basis, to scientists who might otherwise lack access to the expensive tools of modern biology. It is not enough to accomplish cutting-edge research. We must also educate the children and college students of today, as they will be the researchers of tomorrow. Since microbiology provides exceptional teaching tools and is of pivotal importance to understanding biology, science education in schools should be refocused to include microbiology lessons and lab exercises. At the undergraduate level, a thorough knowledge of microbiology should be made a part of the core curriculum for life science majors. Since issues that deal with microbes have a direct bearing on the human condition, it is critical that the public-at-large become better grounded in the basics of microbiology. Public literacy campaigns must identify the issues to be conveyed and the best avenues for communicating those messages. Decision-makers at federal, state, local, and community levels should be made more aware of the ways that microbiology impacts human life and the ways school curricula could be improved to include valuable lessons in microbial science.